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Sharma AK, Nair GB, Dhoble SJ, Kroon RE, Terblans JJ, Swart HC. Luminescence Thermometry Based on the Upconversion Luminescence from the Stark Sublevels of BaY 2F 8:Yb 3+, Tm 3+ Phosphor. J Fluoresc 2024; 34:1039-1048. [PMID: 37450083 PMCID: PMC11062960 DOI: 10.1007/s10895-023-03295-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023]
Abstract
Visible and near-infrared (NIR) upconversion luminescence (UCL) emissions originating from the BaY2F8: Yb3+, Tm3+ systems were investigated under a laser excitation at 980 nm. The BaY2F8:20 mol% Yb3+, x mol% Tm3+ and BaY2F8: y mol% Yb3+, 0.5 mol% Tm3+ phosphors showed prominent UCL at 800 and 810 nm. The optimized doping concentrations of Yb3+ and Tm3+ in the BaY2F8 host matrix were evaluated, their spectroscopic properties were determined, and studies on their temperature-dependent behaviour were carried out. The temperature-sensing properties were studied by generating the fluorescence intensity ratio (FIR) of the UCL peaks originating from the thermally-coupled energy levels of the Tm3+ ions. The Stark sublevels of 1G4 level of Tm3+ ions were utilized to estimate the temperature-sensing abilities of the phosphor.
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Affiliation(s)
- Ashwini K Sharma
- Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa.
- Department of Physics, University, Dr. Shyama Prasad Mukherjee University, Ranchi, 834008, India.
| | - Govind B Nair
- Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa.
| | - S J Dhoble
- Department of Physics, RTM Nagpur University, Nagpur, 440033, India
| | - Robin E Kroon
- Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
| | - J J Terblans
- Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
| | - H C Swart
- Department of Physics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa.
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2
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Salemane K, Coetzee LZ, Pocock G, Genthe B, Taylor MB, Mans J. Water-Based Epidemiological Investigation of Hepatitis E Virus in South Africa. Food Environ Virol 2024:10.1007/s12560-024-09596-1. [PMID: 38613652 DOI: 10.1007/s12560-024-09596-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 03/08/2024] [Indexed: 04/15/2024]
Abstract
Hepatitis E virus (HEV) is an emerging zoonotic pathogen that exhibits great host diversity. The primary means of transmission of the virus in low- and middle-income countries is contaminated water, often due to a lack of access to proper sanitation, which leads to faecal contamination of water sources. Environmental surveillance is an important tool that can be used to monitor virus circulation and as an early warning system for outbreaks. This study was conducted to determine the prevalence and genetic diversity of HEV in wastewater, surface water (rivers and standpipe/ablution water), and effluent from a piggery in South Africa. A total of 536 water samples were screened for HEV using real-time reverse transcription-polymerase chain reaction. Overall, 21.8% (117/536) of the wastewater, river, and ablution water samples tested positive for HEV, whereas 74.4% (29/39) of the samples from the piggery tested positive. Genotyping revealed sequences belonging to HEV genotypes 3 (98%, 53/54) and 4 (2%, 1/54), with subtypes 3c, 3f, and 4b being identified.
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Affiliation(s)
- Karabo Salemane
- Department of Medical Virology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Gezina, Pretoria, 0031, South Africa
| | - Leanne Z Coetzee
- , Waterlab, Techno Park, 23B De Havilland Cres, Persequor, Pretoria, 0020, South Africa
| | - Gina Pocock
- , Waterlab, Techno Park, 23B De Havilland Cres, Persequor, Pretoria, 0020, South Africa
| | - Bettina Genthe
- Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa
| | - Maureen B Taylor
- Department of Medical Virology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Gezina, Pretoria, 0031, South Africa
| | - Janet Mans
- Department of Medical Virology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Private Bag X323, Gezina, Pretoria, 0031, South Africa.
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3
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Vale GA, Hargrove JW, Hope A, Torr SJ. Modelled impact of Tiny Targets on the distribution and abundance of riverine tsetse. PLoS Negl Trop Dis 2024; 18:e0011578. [PMID: 38626189 PMCID: PMC11051647 DOI: 10.1371/journal.pntd.0011578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 04/26/2024] [Accepted: 04/01/2024] [Indexed: 04/18/2024] Open
Abstract
BACKGROUND The insecticide-treated baits known as Tiny Targets are one of the cheapest means of controlling riverine species of tsetse flies, the vectors of the trypanosomes that cause sleeping sickness in humans. Models of the efficacy of these targets deployed near rivers are potentially useful in planning control campaigns and highlighting the principles involved. METHODS AND PRINCIPAL FINDINGS To evaluate the potential of models, we produced a simple non-seasonal model of the births, deaths, mobility and aging of tsetse, and we programmed it to simulate the impact of seven years of target use against the tsetse, Glossina fuscipes fuscipes, in the riverine habitats of NW Uganda. Particular attention was given to demonstrating that the model could explain three matters of interest: (i) good control can be achieved despite the degradation of targets, (ii) local elimination of tsetse is impossible if invasion sources are not tackled, and (iii) with invasion and target degradation it is difficult to detect any effect of control on the age structure of the tsetse population. CONCLUSIONS Despite its simplifications, the model can assist planning and teaching, but allowance should be made for any complications due to seasonality and management challenges associated with greater scale.
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Affiliation(s)
- Glyn A. Vale
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
- Natural Resources Institute, University of Greenwich, Chatham, United Kingdom
| | - John W. Hargrove
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
| | - Andrew Hope
- Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Steve J. Torr
- Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
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4
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Mngwengwe L, Lugongolo MY, Ombinda-Lemboumba S, Ismail Y, Mthunzi-Kufa P. The effects of low-level laser therapy on severe acute respiratory syndrome coronavirus 2 infection in HEK293/ACE2 cells. J Biophotonics 2024; 17:e202300334. [PMID: 38041552 DOI: 10.1002/jbio.202300334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/01/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023]
Abstract
SARS-CoV-2 is a threat to public health due to its ability to undergo crucial mutations, increasing its infectivity and decreasing the vaccine's effectiveness. There is a need to find and introduce alternative and effective methods of controlling SARS-CoV-2. LLLT treats diseases by exposing cells or tissues to low levels of red and near-infrared light. The study aims to investigate for the first time the impact of LLLT on SARS-CoV-2 infected HEK293/ACE2 cells and compare them to uninfected ones. Cells were irradiated at 640 nm, at different fluences. Subsequently, the effects of laser irradiation on the virus and cells were assessed using biological assays. Irradiated uninfected cells showed no changes in cell viability and cytotoxicity, while there were changes in irradiated infected cells. Furthermore, uninfected irradiated cells showed no luciferase activity while laser irradiation reduced luciferase activity in infected cells. Under SEM, there was a clear difference between the infected and uninfected cells.
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Affiliation(s)
- Luleka Mngwengwe
- Council of Scientific and Industrial Research, National Laser Centre, Pretoria, South Africa
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, University Road Westville, Durban, South Africa
| | | | | | - Yaseera Ismail
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, University Road Westville, Durban, South Africa
| | - Patience Mthunzi-Kufa
- Council of Scientific and Industrial Research, National Laser Centre, Pretoria, South Africa
- School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, University Road Westville, Durban, South Africa
- Biomedical Engineering Research Centre, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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5
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Alison J, Payne S, Alexander JM, Bjorkman AD, Clark VR, Gwate O, Huntsaar M, Iseli E, Lenoir J, Mann HMR, Steenhuisen SL, Høye TT. Deep learning to extract the meteorological by-catch of wildlife cameras. Glob Chang Biol 2024; 30:e17078. [PMID: 38273582 DOI: 10.1111/gcb.17078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/09/2023] [Accepted: 11/12/2023] [Indexed: 01/27/2024]
Abstract
Microclimate-proximal climatic variation at scales of metres and minutes-can exacerbate or mitigate the impacts of climate change on biodiversity. However, most microclimate studies are temperature centric, and do not consider meteorological factors such as sunshine, hail and snow. Meanwhile, remote cameras have become a primary tool to monitor wild plants and animals, even at micro-scales, and deep learning tools rapidly convert images into ecological data. However, deep learning applications for wildlife imagery have focused exclusively on living subjects. Here, we identify an overlooked opportunity to extract latent, ecologically relevant meteorological information. We produce an annotated image dataset of micrometeorological conditions across 49 wildlife cameras in South Africa's Maloti-Drakensberg and the Swiss Alps. We train ensemble deep learning models to classify conditions as overcast, sunshine, hail or snow. We achieve 91.7% accuracy on test cameras not seen during training. Furthermore, we show how effective accuracy is raised to 96% by disregarding 14.1% of classifications where ensemble member models did not reach a consensus. For two-class weather classification (overcast vs. sunshine) in a novel location in Svalbard, Norway, we achieve 79.3% accuracy (93.9% consensus accuracy), outperforming a benchmark model from the computer vision literature (75.5% accuracy). Our model rapidly classifies sunshine, snow and hail in almost 2 million unlabelled images. Resulting micrometeorological data illustrated common seasonal patterns of summer hailstorms and autumn snowfalls across mountains in the northern and southern hemispheres. However, daily patterns of sunshine and shade diverged between sites, impacting daily temperature cycles. Crucially, we leverage micrometeorological data to demonstrate that (1) experimental warming using open-top chambers shortens early snow events in autumn, and (2) image-derived sunshine marginally outperforms sensor-derived temperature when predicting bumblebee foraging. These methods generate novel micrometeorological variables in synchrony with biological recordings, enabling new insights from an increasingly global network of wildlife cameras.
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Affiliation(s)
- Jamie Alison
- Department of Ecoscience, Aarhus University, Aarhus, Denmark
| | - Stephanie Payne
- Afromontane Research Unit and Department of Plant Sciences, University of the Free State, Bloemfontein, South Africa
| | - Jake M Alexander
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Anne D Bjorkman
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
| | - Vincent Ralph Clark
- Afromontane Research Unit and Department of Geography, University of the Free State, Bloemfontein, South Africa
| | - Onalenna Gwate
- Afromontane Research Unit and Department of Geography, University of the Free State, Bloemfontein, South Africa
| | - Maria Huntsaar
- Arctic Biology Department, The University Centre in Svalbard (UNIS), Longyearbyen, Norway
- Department of Arctic and Marine Biology, The Arctic University of Norway (UiT), Tromsø, Norway
| | - Evelin Iseli
- Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Jonathan Lenoir
- UMR CNRS 7058 "Ecologie et Dynamique des Systèmes Anthropisés" (EDYSAN), Université de Picardie Jules Verne, Amiens, France
| | - Hjalte Mads Rosenstand Mann
- Department of Ecoscience, Aarhus University, Aarhus, Denmark
- Arctic Research Centre, Aarhus University, Aarhus, Denmark
| | - Sandy-Lynn Steenhuisen
- Afromontane Research Unit and Department of Plant Sciences, University of the Free State, Bloemfontein, South Africa
| | - Toke Thomas Høye
- Department of Ecoscience, Aarhus University, Aarhus, Denmark
- Arctic Research Centre, Aarhus University, Aarhus, Denmark
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6
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van Heerden A, Turon G, Duran-Frigola M, Pillay N, Birkholtz LM. Machine Learning Approaches Identify Chemical Features for Stage-Specific Antimalarial Compounds. ACS Omega 2023; 8:43813-43826. [PMID: 38027377 PMCID: PMC10666252 DOI: 10.1021/acsomega.3c05664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023]
Abstract
Efficacy data from diverse chemical libraries, screened against the various stages of the malaria parasite Plasmodium falciparum, including asexual blood stage (ABS) parasites and transmissible gametocytes, serve as a valuable reservoir of information on the chemical space of compounds that are either active (or not) against the parasite. We postulated that this data can be mined to define chemical features associated with the sole ABS activity and/or those that provide additional life cycle activity profiles like gametocytocidal activity. Additionally, this information could provide chemical features associated with inactive compounds, which could eliminate any future unnecessary screening of similar chemical analogs. Therefore, we aimed to use machine learning to identify the chemical space associated with stage-specific antimalarial activity. We collected data from various chemical libraries that were screened against the asexual (126 374 compounds) and sexual (gametocyte) stages of the parasite (93 941 compounds), calculated the compounds' molecular fingerprints, and trained machine learning models to recognize stage-specific active and inactive compounds. We were able to build several models that predict compound activity against ABS and dual activity against ABS and gametocytes, with Support Vector Machines (SVM) showing superior abilities with high recall (90 and 66%) and low false-positive predictions (15 and 1%). This allowed the identification of chemical features enriched in active and inactive populations, an important outcome that could be mined for essential chemical features to streamline hit-to-lead optimization strategies of antimalarial candidates. The predictive capabilities of the models held true in diverse chemical spaces, indicating that the ML models are therefore robust and can serve as a prioritization tool to drive and guide phenotypic screening and medicinal chemistry programs.
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Affiliation(s)
- Ashleigh van Heerden
- Department
of Biochemistry, Genetics and Microbiology, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Gemma Turon
- Ersilia
Open Source Initiative, 28 Belgrave Road, Cambridge CB1 3DE, U.K.
| | | | - Nelishia Pillay
- Department
of Computer Science, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Lyn-Marié Birkholtz
- Department
of Biochemistry, Genetics and Microbiology, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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7
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Moyo-Gwete T, Richardson SI, Keeton R, Hermanus T, Spencer H, Manamela NP, Ayres F, Makhado Z, Motlou T, Tincho MB, Benede N, Ngomti A, Baguma R, Chauke MV, Mennen M, Adriaanse M, Skelem S, Goga A, Garrett N, Bekker LG, Gray G, Ntusi NAB, Riou C, Burgers WA, Moore PL. Homologous Ad26.COV2.S vaccination results in reduced boosting of humoral responses in hybrid immunity, but elicits antibodies of similar magnitude regardless of prior infection. PLoS Pathog 2023; 19:e1011772. [PMID: 37943890 PMCID: PMC10684107 DOI: 10.1371/journal.ppat.1011772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 11/28/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
The impact of previous SARS-CoV-2 infection on the durability of Ad26.COV2.S vaccine-elicited responses, and the effect of homologous boosting has not been well explored. We followed a cohort of healthcare workers for 6 months after receiving the Ad26.COV2.S vaccine and a further one month after they received an Ad26.COV2.S booster dose. We assessed longitudinal spike-specific antibody and T cell responses in individuals who had never had SARS-CoV-2 infection, compared to those who were infected with either the D614G or Beta variants prior to vaccination. Antibody and T cell responses elicited by the primary dose were durable against several variants of concern over the 6 month follow-up period, regardless of infection history. However, at 6 months after first vaccination, antibody binding, neutralization and ADCC were as much as 59-fold higher in individuals with hybrid immunity compared to those with no prior infection. Antibody cross-reactivity profiles of the previously infected groups were similar at 6 months, unlike at earlier time points, suggesting that the effect of immune imprinting diminishes by 6 months. Importantly, an Ad26.COV2.S booster dose increased the magnitude of the antibody response in individuals with no prior infection to similar levels as those with previous infection. The magnitude of spike T cell responses and proportion of T cell responders remained stable after homologous boosting, concomitant with a significant increase in long-lived early differentiated CD4 memory T cells. Thus, these data highlight that multiple antigen exposures, whether through infection and vaccination or vaccination alone, result in similar boosts after Ad26.COV2.S vaccination.
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Affiliation(s)
- Thandeka Moyo-Gwete
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Simone I. Richardson
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Roanne Keeton
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Tandile Hermanus
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Holly Spencer
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Nelia P. Manamela
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Frances Ayres
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Zanele Makhado
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Thopisang Motlou
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
| | - Marius B. Tincho
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Ntombi Benede
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Amkele Ngomti
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Richard Baguma
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Masego V. Chauke
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
| | - Mathilda Mennen
- Department of Medicine, University of Cape Town and Groote Schuur Hospital; Observatory, South Africa
- Cape Heart Institute, Faculty of Health Sciences, University of Cape Town; Observatory, South Africa
- South African Medical Research Council Extramural Unit on Intersection of Non-communicable Diseases and Infectious Diseases, University of Cape Town, Cape Town, South Africa
| | - Marguerite Adriaanse
- Department of Medicine, University of Cape Town and Groote Schuur Hospital; Observatory, South Africa
- Cape Heart Institute, Faculty of Health Sciences, University of Cape Town; Observatory, South Africa
- South African Medical Research Council Extramural Unit on Intersection of Non-communicable Diseases and Infectious Diseases, University of Cape Town, Cape Town, South Africa
| | - Sango Skelem
- Department of Medicine, University of Cape Town and Groote Schuur Hospital; Observatory, South Africa
- Cape Heart Institute, Faculty of Health Sciences, University of Cape Town; Observatory, South Africa
- South African Medical Research Council Extramural Unit on Intersection of Non-communicable Diseases and Infectious Diseases, University of Cape Town, Cape Town, South Africa
| | - Ameena Goga
- South African Medical Research Council, Cape Town, South Africa
| | - Nigel Garrett
- Centre for the AIDS Programme of Research in South Africa, Durban, South Africa
- Discipline of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Linda-Gail Bekker
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Desmond Tutu HIV Centre, Cape Town, South Africa
| | - Glenda Gray
- South African Medical Research Council, Cape Town, South Africa
| | - Ntobeko A. B. Ntusi
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Department of Medicine, University of Cape Town and Groote Schuur Hospital; Observatory, South Africa
- Cape Heart Institute, Faculty of Health Sciences, University of Cape Town; Observatory, South Africa
- South African Medical Research Council Extramural Unit on Intersection of Non-communicable Diseases and Infectious Diseases, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape Town, Observatory, South Africa
| | - Catherine Riou
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape Town, Observatory, South Africa
| | - Wendy A. Burgers
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Division of Medical Virology, Department of Pathology; University of Cape Town; Observatory, South Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape Town, Observatory, South Africa
| | - Penny L. Moore
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Services, Johannesburg, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Centre for the AIDS Programme of Research in South Africa, Durban, South Africa
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8
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Wilson AM, Coetzee MPA, Wingfield MJ, Wingfield BD. Needles in fungal haystacks: Discovery of a putative a-factor pheromone and a unique mating strategy in the Leotiomycetes. PLoS One 2023; 18:e0292619. [PMID: 37824487 PMCID: PMC10569646 DOI: 10.1371/journal.pone.0292619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/25/2023] [Indexed: 10/14/2023] Open
Abstract
The Leotiomycetes is a hugely diverse group of fungi, accommodating a wide variety of important plant and animal pathogens, ericoid mycorrhizal fungi, as well as producers of antibiotics. Despite their importance, the genetics of these fungi remain relatively understudied, particularly as they don't include model taxa. For example, sexual reproduction and the genetic mechanisms that underly this process are poorly understood in the Leotiomycetes. We exploited publicly available genomic and transcriptomic resources to identify genes of the mating-type locus and pheromone response pathway in an effort to characterize the mating strategies and behaviors of 124 Leotiomycete species. Our analyses identified a putative a-factor mating pheromone in these species. This significant finding represents the first identification of this gene in Pezizomycotina species outside of the Sordariomycetes. A unique mating strategy was also discovered in Lachnellula species that appear to have lost the need for the primary MAT1-1-1 protein. Ancestral state reconstruction enabled the identification of numerous transitions between homothallism and heterothallism in the Leotiomycetes and suggests a heterothallic ancestor for this group. This comprehensive catalog of mating-related genes from such a large group of fungi provides a rich resource from which in-depth, functional studies can be conducted in these economically and ecologically important species.
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Affiliation(s)
- Andi M. Wilson
- Department of Biochemistry, Genetics & Microbiology, Forestry & Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Martin P. A. Coetzee
- Department of Biochemistry, Genetics & Microbiology, Forestry & Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Michael J. Wingfield
- Department of Biochemistry, Genetics & Microbiology, Forestry & Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Brenda D. Wingfield
- Department of Biochemistry, Genetics & Microbiology, Forestry & Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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9
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Mphahlele K, Matjie RH, Bunt JR. Catalytic Effect of Reactive Extraneous Mineral Composites on Char and Tar Distribution during Pyrolysis of Highveld Partially Oxidized Fine-Coal Reject and Its Beneficiated Residues. ACS Omega 2023; 8:36479-36492. [PMID: 37810690 PMCID: PMC10552492 DOI: 10.1021/acsomega.3c05462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023]
Abstract
In this study, the South African partially oxidized fine-coal reject (FCR), which is associated with human health and environmental problems and sustains high disposal expenses, was subjected to density-separation, chemical fractionation, and demineralization experiments to isolate and evaluate the mode of occurrence of mineral-matter (MM) effects on the FCR pyrolysis. A unique composite of two reactive oxides (i.e., MgO and Fe2O3) and a hydrated oxide [i.e., Ca(OH)2] representing major extraneous coal-minerals were blended with either FCR, demineralized FCR, and its beneficiated samples to evaluate the yields of pyrolytic products and activation energy following a novel procedure. The properties of FCR samples and their pyrolytic products were determined by different analyses. Results indicate that the reactive oxides and a hydrated oxide composite addition increased the average activation energy (332.0-476.5 kJ/mol) for FCR due to the initial Ca(OH)2 decomposition and Fe2O3 reduction that took place under pyrolysis conditions. The FCR mineral-rich sink fractions achieved the highest carbon conversion (char yield = 78.8% and tar yield = 5.1%) compared to those of other samples (e.g., <1.9 g/cm3 float char yield = 87.3% and tar yield = 2.3%) evaluated due to higher proportions of calcite/dolomite/pyrite cleats and nonmineral inorganics (Ca, Mg, Na, and Fe) which catalyzed the pyrolysis reactions. On the other hand, CaCO3, CaMg(CO3)2, and metakaolinite formations in the char derived from a blend of reactive oxides and a hydrated oxide composite and FCR interfere with the pyrolysis reactions. Also, deoxygenation reactions were impeded by oxygen present in the reactive oxides and a hydrated oxide composite. The potent catalytic effects of cleat minerals and the extraneous minerals associated with cracking of heavy tars to lighter fractions open opportunities to further understand the mode of occurrence of MM present in FCR during utilization in global pyrolysis. This may reduce waste disposal costs, health-hazards, air-pollution, and FCR volumes and augments feed-coals.
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Affiliation(s)
- Katlego Mphahlele
- Centre of Excellence in Carbon-Based
Fuels, School of Chemical and Mineral Engineering, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520, South Africa
| | - Ratale Henry Matjie
- Centre of Excellence in Carbon-Based
Fuels, School of Chemical and Mineral Engineering, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520, South Africa
| | - John Reginald Bunt
- Centre of Excellence in Carbon-Based
Fuels, School of Chemical and Mineral Engineering, North-West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520, South Africa
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10
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Alade J, Bada SO. Wind-Sifting Separation: A Review. ACS Omega 2023; 8:34196-34205. [PMID: 37780006 PMCID: PMC10536854 DOI: 10.1021/acsomega.3c01087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/12/2023] [Indexed: 10/03/2023]
Abstract
Dry particle classification is a viable alternative to wet classification, both financially and environmentally, and has been used for decades with several approaches and techniques. One of these techniques, the wind-sifting principle, has been observed to be very effective for particle separation. Its separation mode is based on the use of the physical properties of these particles such as size, shape, and density to carry out separation. The principle of wind-sifting has been used to design multiple separators with various configurations for diverse kinds of applications, including recycling, agriculture, furniture, food and beverages, municipal and electronic waste sorting, and even mineral-processing industries. Although the wind-sifting principle has been implemented for various applications, research of this principle is ongoing owing to minimal literature. This Review seeks to provide some literature on wind-sifters as it delves into the three main types, their generic design features, and operational principles.
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Affiliation(s)
| | - Samson Oluwaseyi Bada
- DSI-NRF SARChI Clean Coal Technology
Research Group, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Wits 2050, Johannesburg, South Africa
- University of the Witwatersrand, Wits 2050, Johannesburg, South Africa
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11
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Houle B, Clark SJ, Kabudula CW, Gómez-Olivé FX, Angotti N, Schatz E, Tilstra AM, Mojola SA, Menken J. The effects of HIV and systolic blood pressure on mortality risk in rural South Africa, 2010-2019: a data note. BMC Res Notes 2023; 16:213. [PMID: 37700363 PMCID: PMC10498573 DOI: 10.1186/s13104-023-06478-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 08/29/2023] [Indexed: 09/14/2023] Open
Abstract
OBJECTIVES South Africa is experiencing both HIV and hypertension epidemics. Data were compiled for a study to identify effects of HIV and high systolic blood pressure on mortality risk among people aged 40-plus in a rural South African area experiencing high prevalence of both conditions. We aim to release the replication data set for this study. DATA DESCRIPTION The research data comes from the 2010-11 Ha Nakekela (We Care) population-based survey nested in the Agincourt Health and socio-Demographic Surveillance System (AHDSS) located in the northeast region of South Africa. An age-sex-stratified probability sample was drawn from the AHDSS. The public data set includes information on individual socioeconomic characteristics and measures of HIV status and blood pressure for participants aged 40-plus by 2019. The AHDSS, through its annual surveillance, provided mortality data for nine years subsequent to the survey. These data were converted to person-year observations and linked to the individual-level survey data using participants' AHDSS census identifier. The data can be used to replicate Houle et al. (2022) - which used discrete-time event history models stratified by sex to assess differential mortality risks according to Ha Nakekela measures of HIV-infection, HIV-1 RNA viral load, and systolic blood pressure.
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Affiliation(s)
- Brian Houle
- School of Demography, The Australian National University, Canberra, Australia.
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
| | - Samuel J Clark
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
- Department of Sociology, The Ohio State University, Columbus, OH, USA
| | - Chodziwadziwa W Kabudula
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - F Xavier Gómez-Olivé
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
| | - Nicole Angotti
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
- Department of Sociology, American University, Washington, D.C, USA
| | - Enid Schatz
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
- Department of Public Health, University of Missouri, Columbia, MO, USA
| | - Andrea M Tilstra
- Leverhulme Centre for Demographic Science, Nuffield Department of Population Health, and Nuffield College, University of Oxford, Oxford, UK
| | - Sanyu A Mojola
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), Faculty of Health Sciences, School of Public Health, University of the Witwatersrand, Johannesburg, South Africa
- Department of Sociology, School of Public and International Affairs, and Office of Population Research, Princeton University, Princeton, NJ, USA
| | - Jane Menken
- Institute of Behavioral Science, University of Colorado Boulder, Boulder, CO, USA
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12
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Filiatreau LM, Edwards JK, Masilela N, Gómez-Olivé FX, Haberland N, Pence BW, Maselko J, Muessig KE, Kabudula CW, Dufour MSK, Lippman SA, Kahn K, Pettifor A. Understanding the effects of universal test and treat on longitudinal HIV care outcomes among South African youth: a retrospective cohort study. BMC Public Health 2023; 23:1724. [PMID: 37670262 PMCID: PMC10478421 DOI: 10.1186/s12889-023-16353-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 07/20/2023] [Indexed: 09/07/2023] Open
Abstract
INTRODUCTION Little is known about the effects of universal test and treat (UTT) policies on HIV care outcomes among youth living with HIV (YLHIV). Moreover, there is a paucity of information regarding when YLHIV are most susceptible to disengagement from care under the newest treatment guidelines. The longitudinal HIV care continuum is an underutilized tool that can provide a holistic understanding of population-level HIV care trajectories and be used to compare treatment outcomes across groups. We aimed to explore effects of the UTT policy on longitudinal outcomes among South African YLHIV and identify temporally precise opportunities for re-engaging this priority population in the UTT era. METHODS Using medical record data, we conducted a retrospective cohort study among youth aged 18-24 diagnosed with HIV from August 2015-December 2018 in nine health care facilities in South Africa. We used Fine and Gray sub-distribution proportional hazards models to characterize longitudinal care continuum outcomes in the population overall and stratified by treatment era of diagnosis. We estimated the proportion of individuals in each stage of the continuum over time and the restricted mean time spent in each stage in the first year following diagnosis. Sub-group estimates were compared using differences. RESULTS A total of 420 YLHIV were included. By day 365 following diagnosis, just 23% of individuals had no 90-or-more-day lapse in care and were virally suppressed. Those diagnosed in the UTT era spent less time as ART-naïve (mean difference=-19.3 days; 95% CI: -27.7, -10.9) and more time virally suppressed (mean difference = 17.7; 95% CI: 1.0, 34.4) compared to those diagnosed pre-UTT. Most individuals who were diagnosed in the UTT era and experienced a 90-or-more-day lapse in care disengaged between diagnosis and linkage to care or ART initiation and viral suppression. CONCLUSIONS Implementation of UTT yielded modest improvements in time spent on ART and virally suppressed among South African YLHIV- however, meeting UNAIDS' 95-95-95 targets remains a challenge. Retention in care and re-engagement interventions that can be implemented between diagnosis and linkage to care and between ART initiation and viral suppression (e.g., longitudinal counseling) may be particularly important to improving care outcomes among South African YLHIV in the UTT era.
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Affiliation(s)
- Lindsey M Filiatreau
- Division of Infectious Diseases, School of Medicine, Washington University in St. Louis, St. Louis, USA.
| | - Jessie K Edwards
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nkosinathi Masilela
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - F Xavier Gómez-Olivé
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Brian W Pence
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joanna Maselko
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | - Chodziwadziwa Whiteson Kabudula
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mi-Suk Kang Dufour
- Biostatistics Division, School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Sheri A Lippman
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Division of Prevention Science, Department of Medicine, University of California, San Francisco, CA, USA
| | - Kathleen Kahn
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Audrey Pettifor
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Carolina Population Center, Chapel Hill, NC, USA
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13
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Ghosh A, Orasugh JT, Ray SS, Chattopadhyay D. Integration of 3D Printing-Coelectrospinning: Concept Shifting in Biomedical Applications. ACS Omega 2023; 8:28002-28025. [PMID: 37576662 PMCID: PMC10413848 DOI: 10.1021/acsomega.3c03920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 07/06/2023] [Indexed: 08/15/2023]
Abstract
Porous structures with sizes between the submicrometer and nanometer scales can be produced using efficient and adaptable electrospinning technology. However, to approximate desirable structures, the construction lacks mechanical sophistication and conformance and requires three-dimensional solitary or multifunctional structures. The diversity of high-performance polymers and blends has enabled the creation of several porous structural conformations for applications in advanced materials science, particularly in biomedicine. Two promising technologies can be combined, such as electrospinning with 3D printing or additive manufacturing, thereby providing a straightforward yet flexible technique for digitally controlled shape-morphing fabrication. The hierarchical integration of configurations is used to imprint complex shapes and patterns onto mesostructured, stimulus-responsive electrospun fabrics. This technique controls the internal stresses caused by the swelling/contraction mismatch in the in-plane and interlayer regions, which, in turn, controls the morphological characteristics of the electrospun membranes. Major innovations in 3D printing, along with additive manufacturing, have led to the production of materials and scaffold systems for tactile and wearable sensors, filtration structures, sensors for structural health monitoring, tissue engineering, biomedical scaffolds, and optical patterning. This review discusses the synergy between 3D printing and electrospinning as a constituent of specific microfabrication methods for quick structural prototypes that are expected to advance into next-generation constructs. Furthermore, individual techniques, their process parameters, and how the fabricated novel structures are applied holistically in the biomedical field have never been discussed in the literature. In summary, this review offers novel insights into the use of electrospinning and 3D printing as well as their integration for cutting-edge applications in the biomedical field.
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Affiliation(s)
- Adrija Ghosh
- Department
of Polymer Science and Technology, University
of Calcutta, Kolkata 700009, India
| | - Jonathan Tersur Orasugh
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa
| | - Suprakas Sinha Ray
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa
| | - Dipankar Chattopadhyay
- Department
of Polymer Science and Technology, University
of Calcutta, Kolkata 700009, India
- Center
for Research in Nanoscience and Nanotechnology, Acharya Prafulla Chandra
Roy Sikhsha Prangan, University of Calcutta, JD-2, Sector-III, Saltlake City, Kolkata 700098, India
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14
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Banerjee R, Ray SS. Role of Rheology in Morphology Development and Advanced Processing of Thermoplastic Polymer Materials: A Review. ACS Omega 2023; 8:27969-28001. [PMID: 37576638 PMCID: PMC10413379 DOI: 10.1021/acsomega.3c03310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/10/2023] [Indexed: 08/15/2023]
Abstract
This review presents fundamental knowledge and recent advances pertaining to research on the role of rheology in polymer processing, highlights the knowledge gap between the function of rheology in various processing operations and the importance of rheology in the development, characterization, and assessment of the morphologies of polymeric materials, and offers ideas for enhancing the processabilities of polymeric materials in advanced processing operations. Rheology plays a crucial role in the morphological evolution of polymer blends and composites, influencing the type of morphology in the case of blends and the quality of dispersion in the cases of both blends and composites. The rheological characteristics of multiphase polymeric materials provide valuable information on the morphologies of these materials, thereby rendering rheology an important tool for morphological assessment. Although rheology extensively affects the processabilities of polymeric materials in all processing operations, this review focuses on the roles of rheology in film blowing, electrospinning, centrifugal jet spinning, and the three-dimensional printing of polymeric materials, which are advanced processing operations that have gained significant research interest. This review offers a comprehensive overview of the fundamentals of morphology development and the aforementioned processing techniques; moreover, it covers all vital aspects related to the tailoring of the rheological characteristics of polymeric materials for achieving superior morphologies and high processabilities of these materials in advanced processing operations. Thus, this article provides a direction for future advancements in polymer processing. Furthermore, the superiority of elongational flow over shear flow in enhancing the quality of dispersion in multiphase polymeric materials and the role of extensional rheology in the advanced processing operations of these materials, which have rarely been discussed in previous reviews, have been critically analyzed in this review. In summary, this article offers new insights into the use of rheology in material and product development during advanced polymer-processing operations.
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Affiliation(s)
- Ritima Banerjee
- Department
of Chemical Engineering, Calcutta Institute
of Technology, Banitabla, Uluberia, Howrah, 711316 West Bengal, India
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
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15
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Samsunder N, Lustig G, Ngubane S, Maseko TG, Rambaran S, Ngcapu S, Magini SN, Lewis L, Cawood C, Kharsany ABM, Karim QA, Karim SA, Naidoo K, Sivro A. Field evaluations of four SARS-CoV-2 rapid antigen tests during SARS-CoV-2 Delta variant wave in South Africa. Diagn Progn Res 2023; 7:14. [PMID: 37491317 PMCID: PMC10369830 DOI: 10.1186/s41512-023-00151-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 07/11/2023] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND Rapid antigen tests detecting SARS-CoV-2 were shown to be a useful tool in managing the COVID-19 pandemic. Here, we report on the results of a prospective diagnostic accuracy study of four SARS-CoV-2 rapid antigen tests in a South African setting. METHODS Rapid antigen test evaluations were performed through drive-through testing centres in Durban, South Africa, from July to December 2021. Two evaluation studies were performed: nasal Panbio COVID-19 Ag Rapid Test Device (Abbott) was evaluated in parallel with the nasopharyngeal Espline SARS-CoV-2 Ag test (Fujirebio), followed by the evaluation of nasal RightSign COVID-19 Antigen Rapid test Cassette (Hangzhou Biotest Biotech) in parallel with the nasopharyngeal STANDARD Q COVID-19 Ag test (SD Biosensor). The Abbott RealTime SARS-CoV-2 assay was used as a reference test. RESULTS Evaluation of Panbio and Espline Ag tests was performed on 494 samples (31% positivity), while the evaluation of Standard Q and RightTest Ag tests was performed on 539 samples (13.17% positivity). The overall sensitivity for all four tests ranged between 60 and 72% with excellent specificity values (> 98%). Sensitivity increased to > 80% in all tests in samples with cycle number value < 20. All four tests performed best in samples from patients presenting within the first week of symptom onset. CONCLUSIONS All four evaluated tests detected a majority of the cases within the first week of symptom onset with high viral load.
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Affiliation(s)
- Natasha Samsunder
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Gila Lustig
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Slindile Ngubane
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Thando Glory Maseko
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Santhuri Rambaran
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Sinaye Ngcapu
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa
| | - Stanley Nzuzo Magini
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Lara Lewis
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Cherie Cawood
- Epicentre AIDS Risk Management (Pty) Limited, Durban, South Africa
| | - Ayesha B M Kharsany
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa
| | - Quarraisha Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Department of Epidemiology, Columbia University, New York City, USA
| | - Salim Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Department of Epidemiology, Columbia University, New York City, USA
| | - Kogieleum Naidoo
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- South African Medical Research Council (SAMRC), CAPRISA-TB-HIV Pathogenesis and Treatment Research Unit, University of KwaZulu-Natal Nelson R. Mandela School of Medicine, Durban, South Africa
| | - Aida Sivro
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa.
- Department of Medical Microbiology, University of KwaZulu-Natal, Durban, South Africa.
- South African Medical Research Council (SAMRC), CAPRISA-TB-HIV Pathogenesis and Treatment Research Unit, University of KwaZulu-Natal Nelson R. Mandela School of Medicine, Durban, South Africa.
- JC Wilt Infectious Disease Research Centre, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada.
- Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg, MB, Canada.
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Enebe MC, Erasmus M. Susceptibility and plant immune control-a case of mycorrhizal strategy for plant colonization, symbiosis, and plant immune suppression. Front Microbiol 2023; 14:1178258. [PMID: 37476663 PMCID: PMC10355322 DOI: 10.3389/fmicb.2023.1178258] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/15/2023] [Indexed: 07/22/2023] Open
Abstract
Plants and microbes (mycorrhizal fungi to be precise) have evolved together over the past millions of years into an association that is mutualist. The plants supply the fungi with photosynthates and shelter, while the fungi reciprocate by enhancing nutrient and water uptake by the plants as well as, in some cases, control of soil-borne pathogens, but this fungi-plant association is not always beneficial. We argue that mycorrhizal fungi, despite contributing to plant nutrition, equally increase plant susceptibility to pathogens and herbivorous pests' infestation. Understanding of mycorrhizal fungi strategies for suppressing plant immunity, the phytohormones involved and the signaling pathways that aid them will enable the harnessing of tripartite (consisting of three biological systems)-plant-mycorrhizal fungi-microbe interactions for promoting sustainable production of crops.
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Affiliation(s)
- Matthew Chekwube Enebe
- Centre for Mineral Biogeochemistry, University of the Free State, Bloemfontein, South Africa
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17
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Ghosh A, Orasugh JT, Ray SS, Chattopadhyay D. Prospects of 2D graphdiynes and their applications in desalination and wastewater remediation. RSC Adv 2023; 13:18568-18604. [PMID: 37346946 PMCID: PMC10281012 DOI: 10.1039/d3ra01370g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
Water is an indispensable part of human life that affects health and food intake. Water pollution caused by rapid industrialization, agriculture, and other human activities affects humanity. Therefore, researchers are prudent and cautious regarding the use of novel materials and technologies for wastewater remediation. Graphdiyne (GDY), an emerging 2D nanomaterial, shows promise in this direction. Graphdiyne has a highly symmetrical π-conjugated structure consisting of uniformly distributed pores; hence, it is favorable for applications such as oil-water separation and organic-pollutant removal. The acetylenic linkage in GDY can strongly interact with metal ions, rendering GDY applicable to heavy-metal adsorption. In addition, GDY membranes that exhibit 100% salt rejection at certain pressures are potential candidates for wastewater treatment and water reuse via desalination. This review provides deep insights into the structure, properties, and synthesis methods of GDY, owing to which it is a unique, promising material. In the latter half of the article, various applications of GDY in desalination and wastewater treatment have been detailed. Finally, the prospects of these materials have been discussed succinctly.
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Affiliation(s)
- Adrija Ghosh
- Department of Polymer Science and Technology, University of Calcutta Kolkata-700009 India
| | - Jonathan Tersur Orasugh
- Department of Chemical Sciences, University of Johannesburg Doorfontein Johannesburg 2028 South Africa
- Centre for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific and Industrial Research Pretoria 0001 South Africa
| | - Suprakas Sinha Ray
- Department of Chemical Sciences, University of Johannesburg Doorfontein Johannesburg 2028 South Africa
- Centre for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific and Industrial Research Pretoria 0001 South Africa
| | - Dipankar Chattopadhyay
- Department of Polymer Science and Technology, University of Calcutta Kolkata-700009 India
- Center for Research in Nanoscience and Nanotechnology, Acharya Prafulla Chandra Roy Sikhsha Prangan, University of Calcutta JD-2, Sector-III, Saltlake City Kolkata-700098 WB India
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Manrakhan A, Daneel JH, Serfontein L, Mauda E, Sutton GF, Hattingh V. Efficacy of an existing Ceratitis capitata (Diptera: Tephritidae) cold disinfestation treatment schedule for Ceratitis cosyra. J Econ Entomol 2023; 116:779-789. [PMID: 37030002 DOI: 10.1093/jee/toad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/10/2023] [Accepted: 03/18/2023] [Indexed: 06/14/2023]
Abstract
The efficacy of an existing cold disinfestation postharvest treatment targeting Ceratitis capitata (Wiedemann) in citrus was determined for the marula fly, Ceratitis cosyra (Walker). The cold tolerances of C. capitata and C. cosyra were first quantified in artificial diet at 3.5 °C at different exposure periods for up to 18 days. Ceratitis capitata was found to be more cold tolerant than C. cosyra. At 3.5 °C, the duration to achieve 99.9968% mortality was calculated to be 11.57 days for C. capitata and 9.10 days for C. cosyra. Under an existing C. capitata cold treatment schedule at 1 °C for 14 days, the conditions required for complete mortality of the third larval stage of C. cosyra in orange, Citrus sinensis (L.) Osbeck cv. Valencia, were then determined. No survivors of C. cosyra in oranges were recorded beyond 11 days of cold treatment at 1 °C. The efficacy of this C. capitata treatment for disinfestation of C. cosyra was thereafter confirmed in large scale trials in Valencia oranges. In the large-scale trial at the lowest mean temperature of 1.19 °C for 14 days, there were no survivors from a total of 85 490 treated C. cosyra third instars in oranges. Since C. capitata was shown to be more cold tolerant than C. cosyra and a large scale test demonstrated at least 99.9965% efficacy after 14 days at 1.19 °C, compared with the established effective C. capitata cold treatment of 14 days at 1.11 °C, cold disinfestation treatments for C. capitata should be at least equally effective against C. cosyra.
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Affiliation(s)
- Aruna Manrakhan
- Citrus Research International, PO Box 28, Mbombela 1200, South Africa
- Department of Conservation Ecology and Entomology, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa
| | - John-Henry Daneel
- Citrus Research International, PO Box 28, Mbombela 1200, South Africa
| | - Leani Serfontein
- Citrus Research International, PO Box 28, Mbombela 1200, South Africa
| | - Evans Mauda
- Citrus Research International, PO Box 28, Mbombela 1200, South Africa
| | - Guy F Sutton
- Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, PO Box 94, Makhanda 6140, South Africa
| | - Vaughan Hattingh
- Citrus Research International, PO Box 28, Mbombela 1200, South Africa
- Department of Horticultural Science, Stellenbosch University, Stellenbosch, South Africa
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19
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Kgaphola MJ, Ramoelo A, Odindi J, Mwenge Kahinda JM, Seetal AR, Musvoto C. Impact of land use and land cover change on land degradation in rural semi-arid South Africa: case of the Greater Sekhukhune District Municipality. Environ Monit Assess 2023; 195:710. [PMID: 37219691 PMCID: PMC10205882 DOI: 10.1007/s10661-023-11104-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 03/09/2023] [Indexed: 05/24/2023]
Abstract
In semi-arid regions, interactions between biophysical and socio-economic variables are complex. Such interactions and their respective variables significantly alter land use and land cover, degrade landscape's structure, and impede the efficacy of the adopted land management interventions. This scenario is particularly prevalent in communal land tenure system or areas managed by a hybrid of traditional and state led institutions. Hence, this study sought to investigate the impacts of land use and land cover changes (LULCCs) on land degradation (LD) under communal rural districts, and the key drivers of habitat fragmentation in the Greater Sekhukhune District Municipality (GSDM), South Africa. The study used the wet and dry season multi-temporal remotely sensed image data, key-informant interviews, and workshop with tribal council to determine the major drivers of LULCC and LD. Results revealed that mines and quarries, subsistence and commercial cultivation, and thicket/dense bush LULCs declined significantly during the study period. These LULCs mostly declined in wet season, with loss in vegetation cover highly prevalent. Specifically, the highest conversions were from shrub/grassland to bare soil, thicket/dense bush to shrub/grassland, and shrub/grassland to residential, respectively. Generally, LULCC affected vegetation productivity within the study area, with increased negative NDVI values observed during the dry season. The findings from key informants and the tribal council workshop emphasized that soil erosion, abandonment of cropland, and injudicious land use (i.e. overgrazing and consequent bush encroachment) have severely degraded the land. The study also established that the degrading land can be attributed to the weakening local communal land management system, particularly the weakening tribal councils. The study recommends an urgent need for collaborative (i.e. government, tribal authorities, and land users) land management through designing relevant multi-stakeholder LD mitigation measures.
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Affiliation(s)
- M J Kgaphola
- CSIR, P.O. Box 395, Pretoria, 0001, South Africa.
- School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, 3209, South Africa.
| | - A Ramoelo
- Centre for Environmental Studies, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa
| | - J Odindi
- School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, 3209, South Africa
| | | | - A R Seetal
- CSIR, P.O. Box 395, Pretoria, 0001, South Africa
| | - C Musvoto
- CSIR, P.O. Box 395, Pretoria, 0001, South Africa
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20
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Abrahams-Gessel S, Gómez-Olivé FX, Tollman S, Wade AN, Du Toit JD, Ferro EG, Kabudula CW, Gaziano TA. Improvements in Hypertension Control in the Rural Longitudinal HAALSI Cohort of South African Adults Aged 40 and Older, From 2014 to 2019. Am J Hypertens 2023; 36:324-332. [PMID: 36857463 PMCID: PMC10200554 DOI: 10.1093/ajh/hpad018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/26/2023] [Accepted: 02/28/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Over half of the South African adults aged 45 years and older have hypertension but its effective management along the treatment cascade (awareness, treatment, and control) remains poorly understood. METHODS We compared the prevalence of all stages of the hypertension treatment cascade in the rural HAALSI cohort of older adults at baseline and after four years of follow-up using household surveys and blood pressure data. Hypertension was a mean systolic blood pressure >140 mm Hg or diastolic pressure >90 mm Hg, or current use of anti-hypertension medication. Control was a mean blood pressure <140/90 mm Hg. The effects of sex and age on the treatment cascade at follow-up were assessed. Multivariate Poisson regression models were used to estimate prevalence ratios along the treatment cascade at follow-up. RESULTS Prevalence along the treatment cascade increased from baseline (B) to follow-up (F): awareness (64.4% vs. 83.6%), treatment (49.7% vs. 73.9%), and control (22.8% vs. 41.3%). At both time points, women had higher levels of awareness (B: 70.5% vs. 56.3%; F: 88.1% vs. 76.7%), treatment (B: 55.9% vs. 41.55; F: 79.9% vs. 64.7%), and control (B: 26.5% vs. 17.9%; F: 44.8% vs. 35.7%). Prevalence along the cascade increased linearly with age for everyone. Predictors of awareness included being female, elderly, or visiting a primary health clinic three times in the previous 3 months, and the latter two also predicted hypertension control. CONCLUSIONS There were significant improvements in awareness, treatment, and control of hypertension from baseline to follow-up and women fared better at all stages, at both time points.
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Affiliation(s)
- Shafika Abrahams-Gessel
- Center for Health Decision Science, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - F Xavier Gómez-Olivé
- Harvard Center for Population and Development Studies, Harvard University, Cambridge, Massachusetts, USA
- Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), University of the Witwatersrand, Johannesburg, South Africa
- Africa Wits-INDEPTH Partnership for Genomic Studies, University of the Witwatersrand, Johannesburg, South Africa
| | - Stephen Tollman
- Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), University of the Witwatersrand, Johannesburg, South Africa
- Africa Wits-INDEPTH Partnership for Genomic Studies, University of the Witwatersrand, Johannesburg, South Africa
- Department of Epidemiology and Global Health, Umeå University, Umeå, Sweden
| | - Alisha N Wade
- Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), University of the Witwatersrand, Johannesburg, South Africa
- Africa Wits-INDEPTH Partnership for Genomic Studies, University of the Witwatersrand, Johannesburg, South Africa
| | - Jacques D Du Toit
- Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), University of the Witwatersrand, Johannesburg, South Africa
| | - Enrico G Ferro
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Chodziwadziwa W Kabudula
- Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), University of the Witwatersrand, Johannesburg, South Africa
- Africa Wits-INDEPTH Partnership for Genomic Studies, University of the Witwatersrand, Johannesburg, South Africa
| | - Thomas A Gaziano
- Center for Health Decision Science, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
- Harvard Center for Population and Development Studies, Harvard University, Cambridge, Massachusetts, USA
- Cardiovascular Medicine Division, Brigham & Women’s Hospital, Boston, Massachusetts, USA
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21
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Wilson AM, Wingfield MJ, Wingfield BD. Structure and number of mating pheromone genes is closely linked to sexual reproductive strategy in Huntiella. BMC Genomics 2023; 24:261. [PMID: 37179314 PMCID: PMC10182648 DOI: 10.1186/s12864-023-09355-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 05/05/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Huntiella resides in the Ceratocystidaceae, a family of fungi that accommodates important plant pathogens and insect-associated saprotrophs. Species in the genus have either heterothallic or unisexual (a form of homothallism) mating systems, providing an opportunity to investigate the genetic mechanisms that enable transitions between reproductive strategies in related species. Two newly sequenced Huntiella genomes are introduced in this study and comparative genomics and transcriptomics tools are used to investigate the differences between heterothallism and unisexuality across the genus. RESULTS Heterothallic species harbored up to seven copies of the a-factor pheromone, each of which possessed numerous mature peptide repeats. In comparison, unisexual Huntiella species had only two or three copies of this gene, each with fewer repeats. Similarly, while the heterothallic species expressed up to 12 copies of the mature α-factor pheromone, unisexual species had up to six copies. These significant differences imply that unisexual Huntiella species do not rely on a mating partner recognition system in the same way that heterothallic fungi do. CONCLUSION While it is suspected that mating type-independent pheromone expression is the mechanism allowing for unisexual reproduction in Huntiella species, our results suggest that the transition to unisexuality may also have been associated with changes in the genes governing the pheromone pathway. While these results are specifically related to Huntiella, they provide clues leading to a better understanding of sexual reproduction and the fluidity of mating strategies in fungi more broadly.
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Affiliation(s)
- Andi M Wilson
- Forestry and Agricultural Biotechnology Institute (FABI), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0028, South Africa.
| | - Michael J Wingfield
- Forestry and Agricultural Biotechnology Institute (FABI), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0028, South Africa
| | - Brenda D Wingfield
- Forestry and Agricultural Biotechnology Institute (FABI), Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0028, South Africa
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22
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Roy A, de Beer M, Pillai SK, Ray SS. Application of Layered Double Hydroxides as a Slow-Release Phosphate Source: A Comparison of Hydroponic and Soil Systems. ACS Omega 2023; 8:15017-15030. [PMID: 37151558 PMCID: PMC10157694 DOI: 10.1021/acsomega.2c07862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/14/2023] [Indexed: 05/09/2023]
Abstract
The utilization of slow-release fertilizer materials capable of responding to their environment and releasing nutrient ions efficiently over a prolonged period is an emerging research area in agricultural materials sciences. In this study, two-dimensional layered materials were prepared to release phosphor ions (P) slowly into the soil as well as in the hydroponic system. Various P-intercalated layered double hydroxides (LDHs) (Mg/Al, Zn/Al, and Mg-Zn/Al-LDHs) with a molar ratio of 2:1 were synthesized using an ion-exchange method from corresponding LDHs containing NO3 - ions within the layers. Sodium alginate (SA) was used to encapsulate P-intercalated Mg/Al-LDH to produce bionanocomposite beads (LB) to check the effect of the biopolymer matrix on the release characteristics. The prepared materials were characterized by XRD and FTIR to confirm the incorporation of P in LDHs. TGA, SEM, and elemental analysis were also performed to study the thermal decomposition pattern, surface morphology, and chemical composition of synthesized materials. The P-release experiments were conducted in a soil solution. The performance of the prepared materials was investigated in soil as well as in a hydroponic system for tomato plants under a controlled atmosphere of humidity, temperature, and light. The fertilization ability of the prepared materials was compared with that of a soluble P source (KH2PO4), commercial hydroponic fertilizer (Nutrifeed), and a commercial soil slow-release fertilizer (Wonder plant starter). The prepared materials demonstrated a slow release of P in the soil solution. P-intercalated LDHs were not very effective under hydroponic conditions; however, the LDHs were more effective in the soil system in terms of dry matter production and P content in dry matter. Furthermore, LDHs were able to increase the soil pH value over time.
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Affiliation(s)
- Abhinandan
Singha Roy
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Marinda de Beer
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Sreejarani Kesavan Pillai
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- ;
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23
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Samanta S, Kumar S, Aratikatla EK, Ghorpade SR, Singh V. Recent developments of imidazo[1,2- a]pyridine analogues as antituberculosis agents. RSC Med Chem 2023; 14:644-657. [PMID: 37122538 PMCID: PMC10131611 DOI: 10.1039/d3md00019b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
Over the past 2000 years, tuberculosis (TB) has killed more people than any other infectious disease. In 2021, TB claimed 1.6 million lives worldwide, making it the second leading cause of death from an infectious disease after COVID-19. Unfortunately, TB drug discovery research was neglected in the last few decades of the twentieth century. Recently, the World Health Organization has taken the initiative to develop new TB drugs. Imidazopyridine, an important fused bicyclic 5,6 heterocycle has been recognized as a "drug prejudice" scaffold for its wide range of applications in medicinal chemistry. A few examples of imidazo[1,2-a]pyridine exhibit significant activity against multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Here, we critically review anti-TB compounds of the imidazo[1,2-a]pyridine class by discussing their development based on the structure-activity relationship, mode-of-action, and various scaffold hopping strategies over the last decade, which is identified as a renaissance era of TB drug discovery research.
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Affiliation(s)
- Sauvik Samanta
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Sumit Kumar
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Eswar K Aratikatla
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Sandeep R Ghorpade
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
| | - Vinayak Singh
- Holistic Drug Discovery and Development (H3D) Centre, University of Cape Town Rondebosch 7701 South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Institute of Infectious Disease and Molecular Medicine, University of Cape Town Rondebosch 7701 South Africa
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24
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Pillay S, San JE, Tshiabuila D, Naidoo Y, Pillay Y, Maharaj A, Anyaneji UJ, Wilkinson E, Tegally H, Lessells RJ, Baxter C, de Oliveira T, Giandhari J. Evaluation of miniaturized Illumina DNA preparation protocols for SARS-CoV-2 whole genome sequencing. PLoS One 2023; 18:e0283219. [PMID: 37099540 PMCID: PMC10132692 DOI: 10.1371/journal.pone.0283219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/03/2023] [Indexed: 04/27/2023] Open
Abstract
The global pandemic caused by SARS-CoV-2 has increased the demand for scalable sequencing and diagnostic methods, especially for genomic surveillance. Although next-generation sequencing has enabled large-scale genomic surveillance, the ability to sequence SARS-CoV-2 in some settings has been limited by the cost of sequencing kits and the time-consuming preparations of sequencing libraries. We compared the sequencing outcomes, cost and turn-around times obtained using the standard Illumina DNA Prep kit protocol to three modified protocols with fewer clean-up steps and different reagent volumes (full volume, half volume, one-tenth volume). We processed a single run of 47 samples under each protocol and compared the yield and mean sequence coverage. The sequencing success rate and quality for the four different reactions were as follows: the full reaction was 98.2%, the one-tenth reaction was 98.0%, the full rapid reaction was 97.5% and the half-reaction, was 97.1%. As a result, uniformity of sequence quality indicated that libraries were not affected by the change in protocol. The cost of sequencing was reduced approximately seven-fold and the time taken to prepare the library was reduced from 6.5 hours to 3 hours. The sequencing results obtained using the miniaturised volumes showed comparability to the results obtained using full volumes as described by the manufacturer. The adaptation of the protocol represents a lower-cost, streamlined approach for SARS-CoV-2 sequencing, which can be used to produce genomic data quickly and more affordably, especially in resource-constrained settings.
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Affiliation(s)
- Sureshnee Pillay
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - James Emmanuel San
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Derek Tshiabuila
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Yeshnee Naidoo
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Yusasha Pillay
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Akhil Maharaj
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Ugochukwu J. Anyaneji
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Eduan Wilkinson
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Houriiyah Tegally
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Richard J. Lessells
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Center for AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Cheryl Baxter
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
- Center for AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Tulio de Oliveira
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- Centre for Epidemic Response and Innovation (CERI), School of Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
- Center for AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
- Department of Global Health, University of Washington, Seattle, WA, United States of America
| | - Jennifer Giandhari
- KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP), Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
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25
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Silal SP, Pulliam JRC, Meyer-Rath G, Jamieson L, Nichols BE, Norman J, Hounsell R, Mayet S, Kagoro F, Moultrie H. The National COVID-19 Epi Model (NCEM): Estimating cases, admissions and deaths for the first wave of COVID-19 in South Africa. PLOS Glob Public Health 2023; 3:e0001070. [PMID: 37093784 PMCID: PMC10124849 DOI: 10.1371/journal.pgph.0001070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 03/27/2023] [Indexed: 04/25/2023]
Abstract
In March 2020 the South African COVID-19 Modelling Consortium was formed to support government planning for COVID-19 cases and related healthcare. Models were developed jointly by local disease modelling groups to estimate cases, resource needs and deaths due to COVID-19. The National COVID-19 Epi Model (NCEM) while initially developed as a deterministic compartmental model of SARS-Cov-2 transmission in the nine provinces of South Africa, was adapted several times over the course of the first wave of infection in response to emerging local data and changing needs of government. By the end of the first wave, the NCEM had developed into a stochastic, spatially-explicit compartmental transmission model to estimate the total and reported incidence of COVID-19 across the 52 districts of South Africa. The model adopted a generalised Susceptible-Exposed-Infectious-Removed structure that accounted for the clinical profile of SARS-COV-2 (asymptomatic, mild, severe and critical cases) and avenues of treatment access (outpatient, and hospitalisation in non-ICU and ICU wards). Between end-March and early September 2020, the model was updated 11 times with four key releases to generate new sets of projections and scenario analyses to be shared with planners in the national and provincial Departments of Health, the National Treasury and other partners. Updates to model structure included finer spatial granularity, limited access to treatment, and the inclusion of behavioural heterogeneity in relation to the adoption of Public Health and Social Measures. These updates were made in response to local data and knowledge and the changing needs of the planners. The NCEM attempted to incorporate a high level of local data to contextualise the model appropriately to address South Africa's population and health system characteristics that played a vital role in producing and updating estimates of resource needs, demonstrating the importance of harnessing and developing local modelling capacity.
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Affiliation(s)
- Sheetal Prakash Silal
- Department of Statistical Sciences, Modelling and Simulation Hub, Africa (MASHA), University of Cape Town, Cape Town, South Africa
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Juliet R. C. Pulliam
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Gesine Meyer-Rath
- Department of Internal Medicine, Health Economics and Epidemiology Research Office, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Global Health, School of Public Health, Boston University, Boston, MA, United States of America
| | - Lise Jamieson
- Department of Internal Medicine, Health Economics and Epidemiology Research Office, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Brooke E. Nichols
- Department of Internal Medicine, Health Economics and Epidemiology Research Office, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Global Health, School of Public Health, Boston University, Boston, MA, United States of America
- Department of Medical Microbiology, Amsterdam University Medical Center, Amsterdam, the Netherlands
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | - Jared Norman
- Department of Statistical Sciences, Modelling and Simulation Hub, Africa (MASHA), University of Cape Town, Cape Town, South Africa
| | - Rachel Hounsell
- Department of Statistical Sciences, Modelling and Simulation Hub, Africa (MASHA), University of Cape Town, Cape Town, South Africa
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Saadiyah Mayet
- Department of Statistical Sciences, Modelling and Simulation Hub, Africa (MASHA), University of Cape Town, Cape Town, South Africa
| | - Frank Kagoro
- Division of Clinical Pharmacology, Department of Medicine, Collaborating Centre for Optimising Antimalarial Therapy, University of Cape Town, Cape Town, South Africa
| | - Harry Moultrie
- National Institute for Communicable Diseases (NICD), a Division of the National Health Laboratory Service, Johannesburg, South Africa
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26
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Micklesfield LK, Munthali R, Agongo G, Asiki G, Boua P, Choma SS, Crowther NJ, Fabian J, Gómez-Olivé FX, Kabudula C, Maimela E, Mohamed SF, Nonterah EA, Raal FJ, Sorgho H, Tluway FD, Wade AN, Norris SA, Ramsay M. Identifying the prevalence and correlates of multimorbidity in middle-aged men and women: a cross-sectional population-based study in four African countries. BMJ Open 2023; 13:e067788. [PMID: 36918238 PMCID: PMC10016250 DOI: 10.1136/bmjopen-2022-067788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
OBJECTIVES To determine the prevalence of multimorbidity, to identify which chronic conditions cluster together and to identify factors associated with a greater risk for multimorbidity in sub-Saharan Africa (SSA). DESIGN Cross-sectional, multicentre, population-based study. SETTING Six urban and rural communities in four sub-Saharan African countries. PARTICIPANTS Men (n=4808) and women (n=5892) between the ages of 40 and 60 years from the AWI-Gen study. MEASURES Sociodemographic and anthropometric data, and multimorbidity as defined by the presence of two or more of the following conditions: HIV infection, cardiovascular disease, chronic kidney disease, asthma, diabetes, dyslipidaemia, hypertension. RESULTS Multimorbidity prevalence was higher in women compared with men (47.2% vs 35%), and higher in South African men and women compared with their East and West African counterparts. The most common disease combination at all sites was dyslipidaemia and hypertension, with this combination being more prevalent in South African women than any single disease (25% vs 21.6%). Age and body mass index were associated with a higher risk of multimorbidity in men and women; however, lifestyle correlates such as smoking and physical activity were different between the sexes. CONCLUSIONS The high prevalence of multimorbidity in middle-aged adults in SSA is of concern, with women currently at higher risk. This prevalence is expected to increase in men, as well as in the East and West African region with the ongoing epidemiological transition. Identifying common disease clusters and correlates of multimorbidity is critical to providing effective interventions.
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Affiliation(s)
- Lisa K Micklesfield
- SAMRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Richard Munthali
- SAMRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Godfred Agongo
- Department of Biochemistry and Forensic Sciences, School of Chemical and Biochemical Sciences, C.K. Tedam University of Technology and Applied Sciences, Navrongo, Ghana
- Navrongo Health Research Centre, Ghana Health Service, Accra, Ghana
| | - Gershim Asiki
- African Population and Health Research Center, Nairobi, Kenya
| | - Palwende Boua
- Clinical Research Unit of Nanoro, Institut de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso
- Sydney Brenner Institute of Molecular Bioscience, University of the Witwatersrand, Johannesburg, South Africa
| | - Solomon Sr Choma
- Department of Public Health, University of Limpopo, Sovenga, South Africa
| | - Nigel J Crowther
- Department of Chemical Pathology, National Health Laboratory Service, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - June Fabian
- Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa
| | - Francesc Xavier Gómez-Olivé
- South African Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Chodziwadziwa Kabudula
- South African Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Eric Maimela
- Department of Public Health, University of Limpopo, Sovenga, South Africa
| | - Shukri F Mohamed
- Health and Systems for Health, African Population and Health Research Center, Nairobi, Kenya
| | - Engelbert A Nonterah
- Navrongo Health Research Centre, Ghana Health Service, Accra, Ghana
- Julius Global Health, Julius Centre for Health Sciences and Primary Care, Utrecht University, Utrecht, The Netherlands
| | - Frederick J Raal
- Department of Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Hermann Sorgho
- Institut de Recherche en Sciences de la Santé, Ouagadougou, Burkina Faso
| | - Furahini D Tluway
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Alisha N Wade
- South African Medical Research Council/Wits Rural Public Health and Health Transitions Research Unit, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Shane A Norris
- SAMRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Development and Health, University of Southampton, Southampton, UK
| | - Michele Ramsay
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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27
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Matebese F, Moutloali RM. Integrating Ultrafiltration Membranes with Flocculation and Activated Carbon Pretreatment Processes for Membrane Fouling Mitigation and Metal Ion Removal from Wastewater. ACS Omega 2023; 8:9074-9085. [PMID: 36936310 PMCID: PMC10018693 DOI: 10.1021/acsomega.2c03524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/29/2022] [Indexed: 06/18/2023]
Abstract
The presence of metal ions in an aqueous medium is an ongoing challenge throughout the world. Processes employed for metal ion removal are developed continuously with the integration of these processes taking center stage. Herein, an integrated system consisting of flocculation, activated carbon (AC), and an ultrafiltration (UF) membrane was assessed for the removal of multiple metal ions contained in wastewater generated from a university chemistry research laboratory. The quality of the wastewater was established before and further determined after treatment with inductively coupled plasma optical emission spectrometry (ICP-OES) for metal content, total dissolved solids (TDS), turbidity, electrical conductivity (EC), and pH. Assessing the spent AC indicated minimal structural changes, indicating a potential for further reuse; for instance, the BET for both the pristine and spent AC exhibited type I isotherms with a mesoporous structure, indicating no major structural changes due to metal complexation. The relative performance of the integrated system indicated that the use of flocculation improved the water quality of metal-laden wastewater for safe disposal. The integrated treatment systems exhibited high removal efficiencies between 80 and 99.99% for all the metal ions except for Mn (<0.008 mg L-1) and Cr (<0.016 mg L-1) both at ca. 70%, indicative of the positive influence of the polyelectrolyte in the treatment process. The fabricated UiO-66-NH2@GO membranes (Z4 and Z5) exhibited high fouling resistance and reusability potential as well as relatively high pure water flux. Consequently, the integrated process employed for the treatment of laboratory metal-containing wastewater is promising as a generic approach to improving the quality of metal-containing wastewater to meet the standards of discharging limits in South Africa.
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Affiliation(s)
- Funeka Matebese
- Department
of Chemical Sciences, Faculty of Science, University of Johannesburg, P.O. Box 17011, Doornfontein, 2028Johannesburg, South Africa
- DSI/Mintek
Nanotechnology Innovation Center−UJ Water Research Node, University of Johannesburg, P.O. Box 17011, Doornfontein, 2028Johannesburg, South Africa
| | - Richard M. Moutloali
- Institute
for Nanotechnology and Water Sustainability, College of Science, Engineering
and Technology, University of South Africa, Florida, 1709Johannesburg, South Africa
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28
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Orasugh JT, Ray SS. Functional and Structural Facts of Effective Electromagnetic Interference Shielding Materials: A Review. ACS Omega 2023; 8:8134-8158. [PMID: 36910979 PMCID: PMC9996633 DOI: 10.1021/acsomega.2c05815] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/16/2023] [Indexed: 06/18/2023]
Abstract
Electromagnetic interference (EMI) shielding effectiveness (SE) systems have received immense attention from researchers owing to the rapid development in electronics and telecommunications, which is an alarming matter in our modern society. This radiation can damage the performance of EM devices and may harmfully affect animal/human health. The harmonious utilization of magnetic alloys and conducting but nonmagnetic materials (such as carbon/graphene) is a practical approach toward EMI SE. This review is not exhaustive, although it is comprehensive and aimed at all materials for EMI SE especially graphene-based polymeric composites. It encompasses multifunctional and functional structural EMI shields. These materials comprise polymers, carbons, ceramics, metals, cement composites/nanocomposites, and hybrids. The accessibility of abundant categories of carbon-based materials in their microscale, nanoscale, and quantum forms as EMI shields as polymer-carbon, cement-carbon, ceramic-carbon, metal-carbon, and their hybrids, makes them receive much attention, as a result of their unique amalgamation of electrical, magnetic, dielectric, thermal, and/or mechanical properties. Herewith, we have discussed the principles of EMI shields along with their design and state of the art basis and material architecture along with the drawbacks in research on EMI shields.
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Affiliation(s)
- Jonathan Tersur Orasugh
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, 2028Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, 2028Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria0001, South Africa
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29
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Singha Roy A, Kesavan Pillai S, Ray SS. A Comparison of Nitrate Release from Zn/Al-, Mg/Al-, and Mg-Zn/Al Layered Double Hydroxides and Composite Beads: Utilization as Slow-Release Fertilizers. ACS Omega 2023; 8:8427-8440. [PMID: 36910931 PMCID: PMC9996809 DOI: 10.1021/acsomega.2c07395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Nitrate-loaded Zn/Al, Mg/Al, and Mg-Zn/Al layered double hydroxides (LDHs) were synthesized using the coprecipitation method. The slow-release properties of LDHs were measured in powder form at various pH conditions. Sodium alginate was used to encapsulate Mg/Al LDH to produce composite beads (LB) to further slow down the release of nitrate ions. The prepared LDH samples and LB were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and inductively coupled plasma optical emission spectroscopy. The surface morphologies of LDHs and LB were obtained from scanning electron microscopy analysis. The slow-release properties of the materials were evaluated using a kinetic study of nitrate release in tap water, soil solution, as well as plant growth experiments using coriander (Coriandrum sativum). The nitrate release ability of LDHs and LB was compared with a soluble nitrate source. The plant growth experiments showed that all three LDHs were able to supply an adequate amount of nitrate to the plant similar to the soluble fertilizer while maintaining the availability of nitrate over extended periods. The ability of LDHs to increase soil pH was also demonstrated.
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Affiliation(s)
- Abhinandan Singha Roy
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein 2028, Johannesburg, South
Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Sreejarani Kesavan Pillai
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein 2028, Johannesburg, South
Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
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30
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Abdulsalam J, Otun K, Gardee N, Patel B, Leswifi T, Mathe MK. Activated Biocarbon from Paper Mill Sludge as Electrode Material for Supercapacitors: Comparative Performance Evaluation in Two Aqueous Electrolytes. ACS Omega 2023; 8:5285-5299. [PMID: 36816683 PMCID: PMC9933106 DOI: 10.1021/acsomega.2c05887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 12/16/2022] [Indexed: 06/18/2023]
Abstract
The valorization of a South African paper mill waste sludge into an activated biocarbon electrode material for energy storage application is reported. The valorization method is a two-step synthesis that comprises hydrothermal carbonization and NaOH activation of paper mill waste at 700 °C to produce activated biocarbon. The development of high porosity carbon material with a surface area of 1139 m2/g was observed. The synthesized biocarbon electrode exhibited good specific capacitance (C sp) values of 206 and 157 Fg-1, from a three-electrode cell in neutral (1 M Na2SO4) and alkali (3 M KOH) electrolytes, respectively. The electrolyte concentration purportedly has a considerable effect on specific capacitance. In both electrolytes, symmetric triangular curves in galvanostatic charge-discharge point to a quick charge-discharge process. Synthesized material testing with a two-electrode cell in 3 M KOH and 1 M Na2SO4 electrolytes, respectively, delivered specific capacitances of 125 and 152 Fg-1, with the corresponding energy densities of 17.4 and 21.1 Wh kg-1. The material had capacity retention efficiencies of 83 and 92% after 5000 cycles in 3 M KOH and 1 M Na2SO4 electrolytes, respectively. The electrode material performance of the activated biocarbon from paper sludge clearly shows its potential for electrochemical energy storage. The reported results present an exciting potential contribution of the pulp and paper industry toward the transition to green energy.
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Affiliation(s)
- Jibril Abdulsalam
- Department
of Chemical Engineering, University of South
Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
| | - Kabir Otun
- Institute
for the Development of Energy for African Sustainability, University of South Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
| | - Nasreen Gardee
- Department
of Chemical Engineering, University of South
Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
| | - Bilal Patel
- Department
of Chemical Engineering, University of South
Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
| | - Taile Leswifi
- Department
of Chemical Engineering, University of South
Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
| | - Mahlanyane Kenneth Mathe
- Department
of Chemistry, University of South Africa, Florida Park, Roodepoort, Johannesburg1709, South Africa
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31
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Vale GA, Hargrove JW, Torr SJ. Identification of the area sampled by traps: A modelling study with tsetse. PLoS Negl Trop Dis 2023; 17:e0010902. [PMID: 36706150 PMCID: PMC9910695 DOI: 10.1371/journal.pntd.0010902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 02/09/2023] [Accepted: 01/06/2023] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Sampling with traps provides the most common means of investigating the abundance, composition and condition of tsetse populations. It is thus important to know the size of the area from which the samples originate, but that topic is poorly understood. METHODS AND PRINCIPAL FINDINGS The topic was clarified with the aid of a simple deterministic model of the mobility, births and deaths of tsetse. The model assessed how the sampled area changed according to variations in the numbers, arrangement and catching efficiency of traps deployed for different periods in a large block of homogeneous habitat subject to different levels of fly mortality. The greatest impacts on the size of the sampled area are produced by the flies' mean daily step length and the duration of trapping. There is little effect of trap type. The daily death rate of adult flies is unimportant unless tsetse control measures increase the mortality several times above the low natural rates. CONCLUSIONS Formulae for predicting the probability that any given captured fly originated from various areas around the trap are produced. Using a mean daily step length (d) of 395m, typical of a savannah species of tsetse, any fly caught by a single trap in a 5-day trapping period could be regarded, with roughly 95% confidence, as originating from within a distance of 1.3km of the trap that is from an area of 5.3km2.
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Affiliation(s)
- Glyn A. Vale
- DSI-NRF Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
- Natural Resources Institute, University of Greenwich, Chatham, United Kingdom
- * E-mail: (GAV); (SJT)
| | - John W. Hargrove
- DSI-NRF Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
| | - Steve J. Torr
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail: (GAV); (SJT)
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32
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Moffett BD, Pozuelo JR, van Heerden A, O'Mahen HA, Craske M, Sodi T, Lund C, Orkin K, Kilford EJ, Blakemore SJ, Mahmud M, Musenge E, Davis M, Makhanya Z, Baloyi T, Mahlangu D, Chierchia G, Fielmann SL, Gómez-Olivé FX, Valodia I, Tollman S, Kahn K, Stein A. Digital delivery of behavioural activation therapy to overcome depression and facilitate social and economic transitions of adolescents in South Africa (the DoBAt study): protocol for a pilot randomised controlled trial. BMJ Open 2022; 12:e065977. [PMID: 36585150 PMCID: PMC9809228 DOI: 10.1136/bmjopen-2022-065977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Scalable psychological treatments to address depression among adolescents are urgently needed. This is particularly relevant to low-income and middle-income countries where 90% of the world's adolescents live. While digital delivery of behavioural activation (BA) presents a promising solution, its feasibility, acceptability and effectiveness among adolescents in an African context remain to be shown. METHODS AND ANALYSIS This study is a two-arm single-blind individual-level randomised controlled pilot trial to assess the feasibility, acceptability and initial efficacy of digitally delivered BA therapy among adolescents with depression. The intervention has been coproduced with adolescents at the study site. The study is based in the rural northeast of South Africa in the Bushbuckridge subdistrict of Mpumalanga province. A total of 200 adolescents with symptoms of mild to moderately severe depression on the Patient Health Questionnaire Adolescent Version will be recruited (1:1 allocation ratio). The treatment group will receive BA therapy via a smartphone application (the Kuamsha app) supported by trained peer mentors. The control group will receive an enhanced standard of care. The feasibility and acceptability of the intervention will be evaluated using a mixed methods design, and signals of the initial efficacy of the intervention in reducing symptoms of depression will be determined on an intention-to-treat basis. Secondary objectives are to pilot a range of cognitive, mental health, risky behaviour and socioeconomic measures; and to collect descriptive data on the feasibility of trial procedures to inform the development of a further larger trial. ETHICS AND DISSEMINATION This study has been approved by the University of the Witwatersrand Human Research Ethics Committee (MED20-05-011) and the Oxford Tropical Research Ethics Committee (OxTREC 34-20). Study findings will be published in scientific open access peer-reviewed journals, presented at scientific conferences and communicated to participants, their caregivers, public sector officials and other relevant stakeholders. TRIAL REGISTRATION NUMBERS This trial was registered on 19 November 2020 with the South African National Clinical Trials Registry (DOH-27-112020-5741) and the Pan African Clinical Trials Registry (PACTR202206574814636).
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Affiliation(s)
- Bianca D Moffett
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Julia R Pozuelo
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Alastair van Heerden
- Center for Community Based Research, Human Sciences Research Council, Pietermaritzburg, South Africa
- MRC/Wits Developmental Pathways for Health Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Heather A O'Mahen
- Mood Disorders Centre, Department of Psychology, University of Exeter, Exeter, Devon, UK
| | - Michelle Craske
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles (UCLA), Los Angeles, California, USA
- Department of Psychology, University of California Los Angeles (UCLA), Los Angeles, California, USA
| | - Tholene Sodi
- Psychology, University of Limpopo, Sovenga, Limpopo, South Africa
| | - Crick Lund
- Alan J Flisher Centre for Public Mental Health, Department of Psychiatry and Mental Health, University of Cape Town, Rondebosch, South Africa
- Centre for Global Mental Health, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Kate Orkin
- Blavatnik School of Government, University of Oxford, Oxford, UK
| | - Emma J Kilford
- Department of Clinical, Educational and Health Psychology, University College London, London, UK
| | - Sarah-Jayne Blakemore
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - Mahreen Mahmud
- Department of Economics, University of Exeter, Exeter, UK
| | - Eustasius Musenge
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Meghan Davis
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Zamakhanya Makhanya
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tlangelani Baloyi
- Department of Psychology, University of Limpopo, Polokwane, South Africa
| | - Daniel Mahlangu
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | - F Xavier Gómez-Olivé
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Imraan Valodia
- Southern Centre for Inequality Studies, University of the Witwatersrand, Johannesburg, South Africa
| | - Stephen Tollman
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Umeå Centre for Global Health Research, Division of Epidemiology and Global Health, Department of Public Health and Clinical Medicine, Umeå Universitet, Umea, Sweden
| | - Kathleen Kahn
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Umeå Centre for Global Health Research, Division of Epidemiology and Global Health, Department of Public Health and Clinical Medicine, Umeå Universitet, Umea, Sweden
| | - Alan Stein
- MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Psychiatry, University of Oxford, Oxford, UK
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33
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Iroegbu AC, Ray SS. Nanocellulosics in Transient Technology. ACS Omega 2022; 7:47547-47566. [PMID: 36591168 PMCID: PMC9798511 DOI: 10.1021/acsomega.2c05848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/01/2022] [Indexed: 06/17/2023]
Abstract
Envisage a world where discarded electrical/electronic devices and single-use consumables can dematerialize and lapse into the environment after the end-of-useful life without constituting health and environmental burdens. As available resources are consumed and human activities build up wastes, there is an urgency for the consolidation of efforts and strategies in meeting current materials needs while assuaging the concomitant negative impacts of conventional materials exploration, usage, and disposal. Hence, the emerging field of transient technology (Green Technology), rooted in eco-design and closing the material loop toward a friendlier and sustainable materials system, holds enormous possibilities for assuaging current challenges in materials usage and disposability. The core requirements for transient materials are anchored on meeting multicomponent functionality, low-cost production, simplicity in disposability, flexibility in materials fabrication and design, biodegradability, biocompatibility, and environmental benignity. In this regard, biorenewables such as cellulose-based materials have demonstrated capacity as promising platforms to fabricate scalable, renewable, greener, and efficient materials and devices such as membranes, sensors, display units (for example, OLEDs), and so on. This work critically reviews the recent progress of nanocellulosic materials in transient technologies toward mitigating current environmental challenges resulting from traditional material exploration, usage, and disposal. While spotlighting important fundamental properties and functions in the material selection toward practicability and identifying current difficulties, we propose crucial research directions in advancing transient technology and cellulose-based materials in closing the loop for conventional materials and sustainability.
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Affiliation(s)
- Austine
Ofondu Chinomso Iroegbu
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
& Industrial Research, CSIR, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
& Industrial Research, CSIR, Pretoria 0001, South Africa
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34
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Adekoya G, Adekoya OC, Sadiku RE, Hamam Y, Ray SS. Numerical Investigation and Response Surface Optimization of the Effective Modulus and Electrical and Thermal Conductivities of the Borophene Nanoplatelet-Reinforced PEDOT:PSS Nanocomposite for Energy Storage Application. ACS Omega 2022; 7:48447-48466. [PMID: 36619495 PMCID: PMC9811987 DOI: 10.1021/acsomega.2c06716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Conductive organic nanocomposites have been widely employed to achieve a variety of purposes, particularly for energy storage applications, making it necessary to investigate transport properties such as electron and heat transport qualities based on geometric shapes and component materials. Due to the solid B-B bonds, unique atomic structure, and energy storage potential, borophene has received significant attention due to its reported ultrahigh mechanical modulus and metallic conduction. Herein, we investigated the effect and interaction of content materials (volume fraction) and geometric parameters such as the aspect ratio and orientation of borophene nanoplatelet (BNP) inclusions on the mechanical integrity and transport features (electrical and thermal conductivities) of a poly(3,4-ethylene dioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) electrode. The boundary condition is crucial in developing the predictive models for the optimized mechanical and transport properties of the composites. The effective modulus, electrical conductivity, and thermal conductivity of the BNP-reinforced PEDOT:PSS-based nanocomposite are evaluated using the periodic boundary condition, the representative volume element-based finite element homogenization, and statistical analysis response surface techniques. The optimal parameters for the PEDOT:PSS/BNP nanocomposite for energy storage application are predicted based on the desirability function to have a 13.96% volume fraction of BNPs, having an aspect ratio of 0.04 at 45° inclination. The desirability value achieved for the material hinges was 0.78 with a predicted Young's modulus of 6.73 GPa, the electrical conductivity was 633.85 S/cm, and the thermal conductivity was 1.96 W/m K at a generally high predictive performance of <0.03 error. The effective thermal conductivity of the nanocomposite was determined by considering Kapitsa nanoeffects, which exhibit an interfacial thermal resistance of 2.42 × 10-9 m2 K/W. Based on these improved findings, the enhanced PEDOT:PSS/BNP nanocomposite electrode would be a promising material for metal-ion batteries.
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Affiliation(s)
- Gbolahan
Joseph Adekoya
- Institute
of NanoEngineering Research (INER) & Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria0183, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, CSIR, Pretoria0001, South Africa
| | - Oluwasegun Chijioke Adekoya
- Institute
of NanoEngineering Research (INER) & Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria0183, South Africa
| | - Rotimi Emmanuel Sadiku
- Institute
of NanoEngineering Research (INER) & Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria0183, South Africa
| | - Yskandar Hamam
- Department
of Electrical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria0183, South Africa
- École
Supérieure d’Ingénieurs en Électrotechnique
et Électronique, Cité Descartes, 2 Boulevard Blaise Pascal, Noisy-le-Grand, Paris93160, France
| | - Suprakas Sinha Ray
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, CSIR, Pretoria0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doornforntein2028, Johannesburg, South Africa
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Ipadeola AK, Eid K, Abdullah AM, Al-Hajri RS, Ozoemena KI. Correction: Pd/Ni-metal-organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range. Nanoscale Adv 2022; 5:300. [PMID: 36605815 PMCID: PMC9765424 DOI: 10.1039/d2na90092k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 06/17/2023]
Abstract
[This corrects the article DOI: 10.1039/D2NA00455K.].
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Affiliation(s)
| | - Kamel Eid
- Gas Processing Center (GPC), College of Engineering, Qatar University Doha 2713 Qatar
| | | | - Rashid S Al-Hajri
- Petroleum and Chemical Engineering Department, Sultan Qaboos University Muscat Oman
| | - Kenneth I Ozoemena
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand Private Bag 3, PO Wits Johannesburg 2050 South Africa
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36
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Mkhonto PP, Ngoepe PE. Reconstruction of Cooperite (PtS) Surfaces: A DFT-D+U Study. ACS Omega 2022; 7:43390-43410. [PMID: 36506214 PMCID: PMC9730779 DOI: 10.1021/acsomega.2c02867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/08/2022] [Indexed: 06/17/2023]
Abstract
Cooperite (PtS) is one of the main sources of platinum in the world and has not been given much attention, in particular from the computational aspect. Besides, the surface stability of cooperite is not fully understood, in particular the preferred surface cleavage. In the current study, we employed computer modeling methods within the plane-wave framework of density functional theory with dispersion correction and the U parameter to correctly predict the bulk and surface properties. We reconstructed and calculated the geometries and surface energies of (001), (100), (101), (112), (110), (111), and (211) cooperite surfaces of stoichiometric planes. The Pt d-orbitals with U = 4.5 eV and S p-orbitals with U = 5.5 eV were found optimum to correctly predict a band gap of 1.408 eV for the bulk cooperite model, which agreed with an experimental value of 1.41 eV. The PtS-, Pt-, and S-terminated surfaces were investigated. The structural and electronic properties of the reconstructed surfaces were discussed in detail. We observed one major mechanism of relaxation of cooperite surface reconstructions that emerged from this study, which was the formation of Pt-Pt bonds. It emanated that the (110) and (111) cooperite surfaces underwent significant reconstruction in which the Pt2+ cation relaxed into the surface, forming new Pt-Pt (Pt2 2+) bonds. Similar behavior was perceived for (101) and (211) surfaces, where the Pt2+ cation relaxed inward and sideways on the surface, forming new Pt-Pt (Pt2 2+) bonds. The surface stability decreased in the order (101) > (100) ≈ (112) > (211) > (111) > (110) > (001), indicating that the (101) surface was the most stable, leading to an octahedron cooperite crystal morphology with truncated corners under equilibrium conditions. However, the electronic structures indicated that the chemical reactivity stability of the surfaces would be determined by band gaps. It was found that the (112) surface had a larger band gap than the other surfaces and thus was a chemical stability competitor to the (101) surface. In addition, it was established that the surfaces had different reactivities, which largely depended on the atomic coordination and charge state based on population atomic charges. This study has shown that cooperite has many planes/surface cleavages as determined by the computed crystal morphology, which is in agreement with experimental X-ray diffraction (XRD) pattern findings and the formation of irregular morphology shapes.
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Ipadeola AK, Eid K, Abdullah AM, Al-Hajri RS, Ozoemena KI. Pd/Ni-metal-organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range. Nanoscale Adv 2022; 4:5044-5055. [PMID: 36504739 PMCID: PMC9680948 DOI: 10.1039/d2na00455k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/04/2022] [Indexed: 05/26/2023]
Abstract
Metal nanocrystal ornamented metal-organic frameworks (MOFs) are of particular interest in multidisciplinary applications; however, their electrocatalytic CO oxidation performance over wide pH ranges is not yet reported. Herein, Ni-MOF-derived hierarchical porous carbon nanosheets (Ni-MOF/PC) with abundant Ni-N x sites decorated with Pd nanocrystals (Pd/Ni-MOF/PC) were synthesized by microwave-irradiation (MW-I) followed by annealing at 900 °C and subsequent etching of Ni-MOF/C prior to Pd deposition. The fabrication mechanism comprises the generation of self-reduced reducing gases from triethylamine during the annealing and selective chemical etching of Ni, thereby facilitating the reduction of Ni-anchored MOF and Pd nanocrystal deposition with the aid of ethylene glycol and MW-I to yield Pd/Ni-N x enriched MOF/PC. The synthetic strategies endear the Pd/Ni-MOF/PC with unique physicochemical merits: abundant defects, interconnected pores, high electrical conductivity, high surface area, Ni-deficient but more active sites for Pd/Ni-N x in porous carbon nanosheets, and synergism. These merits endowed the CO oxidation activity and stability on Pd/Ni-MOF/PC substantially than those of Pd/Ni-MOF/C and Pd/C catalysts in wide pH conditions (i.e., KOH, HClO4, and NaHCO3). The CO oxidation activity study reveals the utilization of MOF/PC with metal nanocrystals (Pd/Ni) in CO oxidation catalysis.
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Affiliation(s)
| | - Kamel Eid
- Gas Processing Center (GPC), College of Engineering, Qatar University Doha 2713 Qatar
| | | | - Rashid S Al-Hajri
- Petroleum and Chemical Engineering Department, Sultan Qaboos University Muscat Oman
| | - Kenneth I Ozoemena
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand Private Bag 3, PO Wits Johannesburg 2050 South Africa
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38
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Singh V, Grzegorzewicz AE, Fienberg S, Müller R, Khonde LP, Sanz O, Alfonso S, Urones B, Drewes G, Bantscheff M, Ghidelli-Disse S, Ioerger TR, Angala B, Liu J, Lee RE, Sacchettini JC, Krieger IV, Jackson M, Chibale K, Ghorpade SR. 1,3-Diarylpyrazolyl-acylsulfonamides Target HadAB/BC Complex in Mycobacterium tuberculosis. ACS Infect Dis 2022; 8:2315-2326. [PMID: 36325756 PMCID: PMC9673142 DOI: 10.1021/acsinfecdis.2c00392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Indexed: 11/05/2022]
Abstract
Alternative mode-of-inhibition of clinically validated targets is an effective strategy for circumventing existing clinical drug resistance. Herein, we report 1,3-diarylpyrazolyl-acylsulfonamides as potent inhibitors of HadAB/BC, a 3-hydroxyl-ACP dehydratase complex required to iteratively elongate the meromycolate chain of mycolic acids in Mycobacterium tuberculosis (Mtb). Mutations in compound 1-resistant Mtb mutants mapped to HadC (Rv0637; K157R), while chemoproteomics confirmed the compound's binding to HadA (Rv0635), HadB (Rv0636), and HadC. The compounds effectively inhibited the HadAB and HadBC enzyme activities and affected mycolic acid biosynthesis in Mtb, in a concentration-dependent manner. Unlike known 3-hydroxyl-ACP dehydratase complex inhibitors of clinical significance, isoxyl and thioacetazone, 1,3-diarylpyrazolyl-acylsulfonamides did not require activation by EthA and thus are not liable to EthA-mediated resistance. Further, the crystal structure of a key compound in a complex with Mtb HadAB revealed unique binding interactions within the active site of HadAB, providing a useful tool for further structure-based optimization of the series.
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Affiliation(s)
- Vinayak Singh
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, Department of Chemistry and Institute of Infectious Disease
and Molecular Medicine, University of Cape
Town, Rondebosch7701, South Africa
| | - Anna E. Grzegorzewicz
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado80523-1682, United States
| | - Stephen Fienberg
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
| | - Rudolf Müller
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
| | - Lutete Peguy Khonde
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
| | - Olalla Sanz
- Global
Health Pharma Research Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid28760, Spain
| | - Salvatore Alfonso
- Global
Health Pharma Research Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid28760, Spain
| | - Beatriz Urones
- Global
Health Pharma Research Unit, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid28760, Spain
| | - Gerard Drewes
- Cellzome
GmbH · A GSK Company, Meyerhofstrasse 1, Heidelberg69117, Germany
| | - Marcus Bantscheff
- Cellzome
GmbH · A GSK Company, Meyerhofstrasse 1, Heidelberg69117, Germany
| | | | - Thomas R. Ioerger
- Department
of Computer Science and Engineering, Texas
A&M University, College
Station, Texas77843, United States
| | - Bhanupriya Angala
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado80523-1682, United States
| | - Jiuyu Liu
- Department
of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee38105, United States
| | - Richard E. Lee
- Department
of Chemical Biology & Therapeutics, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee38105, United States
| | - James C. Sacchettini
- Texas A&M
University, Department of Biochemistry and
Biophysics, ILSB 2138,
301 Old Main Dr, College Station, Texas77843-3474, United States
| | - Inna V. Krieger
- Texas A&M
University, Department of Biochemistry and
Biophysics, ILSB 2138,
301 Old Main Dr, College Station, Texas77843-3474, United States
| | - Mary Jackson
- Mycobacteria
Research Laboratories, Department of Microbiology, Immunology and
Pathology, Colorado State University, Fort Collins, Colorado80523-1682, United States
| | - Kelly Chibale
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, Department of Chemistry and Institute of Infectious Disease
and Molecular Medicine, University of Cape
Town, Rondebosch7701, South Africa
| | - Sandeep R. Ghorpade
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch7701, South Africa
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Adekoya G, Adekoya OC, Sadiku RE, Hamam Y, Ray SS. Applications of MXene-Containing Polypyrrole Nanocomposites in Electrochemical Energy Storage and Conversion. ACS Omega 2022; 7:39498-39519. [PMID: 36385802 PMCID: PMC9648120 DOI: 10.1021/acsomega.2c02706] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
The atomically thick two-dimensional (2D) materials are at the forefront of revolutionary technologies for energy storage devices. Due to their fascinating physical and chemical features, these materials have gotten a lot of attention. They are particularly appealing for a wide range of applications, including electrochemical storage systems, due to their simplicity of property tuning. The MXene is a type of 2D material that is widely recognized for its exceptional electrochemical characteristics. The use of these materials in conjunction with conducting polymers, notably polypyrrole (PPy), has opened new possibilities for lightweight, flexible, and portable electrodes. Therefore, herein we report a comprehensive review of recent achievements in the production of MXene/PPy nanocomposites. The structural-property relationship of this class of nanocomposites was taken into consideration with an elaborate discussion of the various characterizations employed. As a result, this research gives a narrative explanation of how PPy interacts with distinct MXenes to produce desirable high-performance nanocomposites. The effects of MXene incorporation on the thermal, electrical, and electrochemical characteristics of the resultant nanocomposites were discussed. Finally, it is critically reviewed and presented as an advanced composite material in electrochemical storage devices, energy conversion, electrochemical sensors, and electromagnetic interference shielding.
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Affiliation(s)
- Gbolahan
Joseph Adekoya
- Institute
of Nanoengineering Research (INER) and Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, CSIR, Pretoria 0001, South Africa
| | - Oluwasegun Chijioke Adekoya
- Institute
of Nanoengineering Research (INER) and Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Rotimi Emmanuel Sadiku
- Institute
of Nanoengineering Research (INER) and Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Yskandar Hamam
- Department
of Electrical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
- École
Supérieure d’Ingénieurs en Électrotechnique
et Électronique, Cité Descartes, 2 Boulevard Blaise Pascal, 93160 Noisy-le-Grand, Paris, France
| | - Suprakas Sinha Ray
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, CSIR, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doornforntein, Johannesburg 2028, South Africa
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40
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Orasugh J, Ray SS. Graphene-Based Electrospun Fibrous Materials with Enhanced EMI Shielding: Recent Developments and Future Perspectives. ACS Omega 2022; 7:33699-33718. [PMID: 36188266 PMCID: PMC9520699 DOI: 10.1021/acsomega.2c03579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/19/2022] [Indexed: 06/16/2023]
Abstract
As a result of advancements in electronics/telecommunications, electromagnetic interference (EMI) pollution has gotten worse. Hence, fabrication/investigation of EMI shields having outstanding EMI shielding performance is necessary. Electrospinning (ES) has recently been established in several niches where 1D nanofibers (NFs) fabricated by ES can provide the shielding of EM waves, owing to their exceptional benefits. This review presents the basic correlations of ES technology and EMI shielding. Diverse graphene (GP)-based fibrous materials directly spun via ES as EMI shields are discussed. Electrospun EMI shields as composites through diverse post-treatments are reviewed, and then different factors influencing their EMI shielding characteristics are critically summarized. Finally, deductions and forthcoming outlooks are given. This review provides up to date knowledge on the advancement of the application of graphene-based electrospun fibers/composite materials as EMI shields and the outlook for high-performance electrospun fibers/composite-based EMI shielding materials.
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Affiliation(s)
- Jonathan
Tersur Orasugh
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
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41
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Adekoya O, Adekoya GJ, Sadiku RE, Hamam Y, Ray SS. Density Functional Theory Interaction Study of a Polyethylene Glycol-Based Nanocomposite with Cephalexin Drug for the Elimination of Wound Infection. ACS Omega 2022; 7:33808-33820. [PMID: 36188269 PMCID: PMC9520710 DOI: 10.1021/acsomega.2c02347] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/26/2022] [Indexed: 05/13/2023]
Abstract
In this paper, density functional theory (DFT) simulations are used to evaluate the possible use of a graphene oxide-based poly(ethylene glycol) (GO/PEG) nanocomposite as a drug delivery substrate for cephalexin (CEX), an antibiotic drug employed to treat wound infection. First, the stable configuration of the PEGylated system was generated with a binding energy of -25.67 kcal/mol at 1.62 Å through Monte Carlo simulation and DFT calculation for a favorable adsorption site. The most stable configuration shows that PEG interacts with GO through hydrogen bonding of the oxygen atom on the hydroxyl group of PEG with the hydrogen atom of the carboxylic group on GO. Similarly, for the interaction of the CEX drug with the GO/PEG nanocomposite excipient system, the adsorption energies are computed after determining the optimal and thermodynamically favorable configuration. The nitrogen atom from the amine group of the drug binds with a hydrogen atom from the carboxylic group of the GO/PEG nanocomposite at 1.75 Å, with an adsorption energy of -36.17 kcal/mol, in the most stable drug-excipient system. Drug release for tissue regeneration at the predicted target cell is more rapid in moist conditions than in the gas phase. The solubility of the suggested drug in the aqueous media around the open wound is shown by the magnitude of the predicted solvation energy. The findings from this study theoretically validate the potential use of a GO/PEG nanocomposite for wound treatment application as a drug carrier for sustained release of the CEX drug.
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Affiliation(s)
- Oluwasegun
Chijioke Adekoya
- Institute
of Nanoengineering Research (INER), Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Gbolahan Joseph Adekoya
- Institute
of Nanoengineering Research (INER), Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Rotimi Emmanuel Sadiku
- Institute
of Nanoengineering Research (INER), Department of Chemical, Metallurgical
and Materials Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Yskandar Hamam
- Department
of Electrical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Pretoria 001, South Africa
- École
Supérieure d’Ingénieurs en Électrotechnique
et Électronique, Cité Descartes, 2 Boulevard Blaise Pascal, Noisy-le-Grand, Paris 93160, France
| | - Suprakas Sinha Ray
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doornforntein, Johannesburg 2028, South
Africa
- , ,
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42
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Scheepers C, Kgagudi P, Mzindle N, Gray ES, Moyo-Gwete T, Lambson BE, Oosthuysen B, Mabvakure B, Garrett NJ, Abdool Karim SS, Morris L, Moore PL. Dependence on a variable residue limits the breadth of an HIV MPER neutralizing antibody, despite convergent evolution with broadly neutralizing antibodies. PLoS Pathog 2022; 18:e1010450. [PMID: 36054228 PMCID: PMC9477419 DOI: 10.1371/journal.ppat.1010450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 09/15/2022] [Accepted: 08/14/2022] [Indexed: 11/18/2022] Open
Abstract
Broadly neutralizing antibodies (bNAbs) that target the membrane-proximal external region (MPER) of HIV gp41 envelope, such as 4E10, VRC42.01 and PGZL1, can neutralize >80% of viruses. These three MPER-directed monoclonal antibodies share germline antibody genes (IGHV1-69 and IGKV3-20) and form a bNAb epitope class. Furthermore, convergent evolution within these two lineages towards a 111.2GW111.3 motif in the CDRH3 is known to enhance neutralization potency. We have previously isolated an MPER neutralizing antibody, CAP206-CH12, that uses these same germline heavy and light chain genes but lacks breadth (neutralizing only 6% of heterologous viruses). Longitudinal sequencing of the CAP206-CH12 lineage over three years revealed similar convergent evolution towards 111.2GW111.3 among some lineage members. Mutagenesis of CAP206-CH12 from 111.2GL111.3 to 111.2GW111.3 and the introduction of the double GWGW motif into CAP206-CH12 modestly improved neutralization potency (2.5–3-fold) but did not reach the levels of potency of VRC42.01, 4E10 or PGZL1. To explore the lack of potency/breadth, viral mutagenesis was performed to map the CAP206-CH12 epitope. This indicated that CAP206-CH12 is dependent on D674, a highly variable residue at the solvent-exposed elbow of MPER. In contrast, VRC42.01, PGZL1 and 4E10 were dependent on highly conserved residues (W672, F673, T676, and W680) facing the hydrophobic patch of the MPER. Therefore, while CAP206-CH12, VRC42.01, PGZL1 and 4E10 share germline genes and show some evidence of convergent evolution, their dependence on different amino acids, which impacts orientation of binding to the MPER, result in differences in breadth and potency. These data have implications for the design of HIV vaccines directed at the MPER epitope. Germline-targeting immunogens are a promising HIV vaccine design strategy. This approach is reliant on the identification of broadly neutralizing antibody (bNAb) classes, which use the same germline antibody genes to target the same viral epitopes. Here, we compare four HIV Envelope MPER-directed antibodies (4E10, VRC42.01, PGZL1 and CAP206-CH12) that despite having shared antibody genes, show distinct neutralization profiles. We show that CAP206-CH12 is dependent on a highly variable residue in the MPER, which results in low neutralization breadth. In contrast, the 4E10, PGZL1 and VRC42.01 mAbs are dependent on highly conserved residues in the MPER, resulting in exceptional neutralization breadth. Our data suggest that while shared germline genes within bNAb epitope classes are required, in some cases these are not sufficient to produce neutralization breadth, and MPER immunogens will need to trigger responses to conserved sites.
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Affiliation(s)
- Cathrine Scheepers
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Prudence Kgagudi
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Nonkululeko Mzindle
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Elin S. Gray
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Thandeka Moyo-Gwete
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Bronwen E. Lambson
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Brent Oosthuysen
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Batsirai Mabvakure
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Nigel J. Garrett
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), KwaZulu-Natal, South Africa
| | - Salim S. Abdool Karim
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), KwaZulu-Natal, South Africa
- Department of Epidemiology, Columbia University, New York City, New York, United States of America
| | - Lynn Morris
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), KwaZulu-Natal, South Africa
- * E-mail: (LM); (PLM)
| | - Penny L. Moore
- Centre for HIV and STIs, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- SA MRC Antibody Immunity Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), KwaZulu-Natal, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- * E-mail: (LM); (PLM)
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Perofsky AC, Tempia S, Bingham J, Maslo C, Toubkin M, Laubscher A, Walaza S, Pulliam JRC, Viboud C, Cohen C. Direct and Indirect Effects of the Coronavirus Disease 2019 Pandemic on Private Healthcare Utilization in South Africa, March 2020-September 2021. Clin Infect Dis 2022; 75:e1000-e1010. [PMID: 35084450 PMCID: PMC8807275 DOI: 10.1093/cid/ciac055] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic caused severe disruptions to healthcare in many areas of the world, but data remain scarce for sub-Saharan Africa. METHODS We evaluated trends in hospital admissions and outpatient emergency department (ED) and general practitioner (GP) visits to South Africa's largest private healthcare system during 2016-2021. We fit time series models to historical data and, for March 2020-September 2021, quantified changes in encounters relative to baseline. RESULTS The nationwide lockdown on 27 March 2020 led to sharp reductions in care-seeking behavior that persisted for 18 months after initial declines. For example, total admissions dropped 59.6% (95% confidence interval [CI], 52.4-66.8) during home confinement and were 33.2% (95% CI, 29-37.4) below baseline in September 2021. We identified 3 waves of all-cause respiratory encounters consistent with COVID-19 activity. Intestinal infections and non-COVID-19 respiratory illnesses experienced the most pronounced declines, with some diagnoses reduced 80%, even as nonpharmaceutical interventions (NPIs) relaxed. Non-respiratory hospitalizations, including injuries and acute illnesses, were 20%-60% below baseline throughout the pandemic and exhibited strong temporal associations with NPIs and mobility. ED attendances exhibited trends similar to those for hospitalizations, while GP visits were less impacted and have returned to pre-pandemic levels. CONCLUSIONS We found substantially reduced use of health services during the pandemic for a range of conditions unrelated to COVID-19. Persistent declines in hospitalizations and ED visits indicate that high-risk patients are still delaying seeking care, which could lead to morbidity or mortality increases in the future.
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Affiliation(s)
- Amanda C Perofsky
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States
| | - Stefano Tempia
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy Bingham
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa
| | - Caroline Maslo
- Clinical Division, Netcare Limited, Johannesburg, South Africa
| | - Mande Toubkin
- Emergency and Trauma Department, Netcare Limited, Johannesburg, South Africa
| | | | - Sibongile Walaza
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Juliet R C Pulliam
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa
| | - Cécile Viboud
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States
| | - Cheryl Cohen
- Centre for Respiratory Diseases and Meningitis, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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44
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Maenetja KP, Ngoepe PE. Unravelling the Catalytic Activity of MnO 2, TiO 2, and VO 2 (110) Surfaces by Oxygen Coadsorption on Sodium-Adsorbed MO 2 {M = Mn, Ti, V}. ACS Omega 2022; 7:25991-25998. [PMID: 35936399 PMCID: PMC9352334 DOI: 10.1021/acsomega.1c05990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metal-air batteries have attracted extensive research interest owing to their high theoretical energy density. However, most of the previous studies have been limited by applying pure oxygen in the cathode, without taking into consideration the effect of the catalyst, which plays a significant role in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Adsorption of oxygen on (110) Na-MO2 is investigated, using density functional theory (DFT) calculations, which is important in the discharging and charging of Na-air batteries. Adsorption of oxygen on Na/MO2 was investigated, and it was observed that the catalysts encourage the formation of the discharge product reported in the literature, i.e., NaO2. The surface NaO2 appears to have bond lengths comparable to those reported for monomer NaO2.
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45
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Mabuea B, Swart HC, Erasmus E. Photocatalytic Decomposition of an Azo Dye Using Transition-Metal-Doped Tungsten and Molybdenum Carbides. ACS Omega 2022; 7:23401-23411. [PMID: 35847302 PMCID: PMC9280970 DOI: 10.1021/acsomega.2c01727] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The preparation, characterization, and photocatalytic application of tungsten or molybdenum carbides (Ni-WC, 1, Co-WC, 2, Ni-MoC, 3, Co-MoC, 4, NiCo-WC, 5, NiCo-MoC, 6, NiFe-WC, 7, and NiFe-MoC, 8) doped with transition metals (Fe, Co, and Ni) are reported. These transition-metal carbide (TMC) particles show that the submicrometer globular particles agglomerated to form larger particles, with smaller crystallites present on the surface of the large particles. These crystallite sizes range between 4 and 34 nm (as calculated from X-ray diffraction data) depending on the metal dopant and type of carbide. Oxidation of the metal carbides is evident from the two sets of photoelectron lines present in the X-ray photoelectron spectroscopy (XPS) of the W 4f area. The Mo 3d spectra reveal four sets of photoelectron lines associated with oxidized MoO2 and MoO3 as well as Mo2+ and Mo3+ associated with MoC1-x . The XPS of the dopant metals Ni, Co, and Fe also show partial oxidation. The photocatalytic decomposition of Congo red (an azo dye) is used as a model reaction to determine the photocatalytic activities of the transition-metal carbides, which is related to the TMCs' optical band gap energies.
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Affiliation(s)
- Busisiwe
Petunia Mabuea
- Department
of Physics, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa
| | | | - Elizabeth Erasmus
- Department
of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa
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46
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Singha Roy A, Kesavan Pillai S, Ray SS. Layered Double Hydroxides for Sustainable Agriculture and Environment: An Overview. ACS Omega 2022; 7:20428-20440. [PMID: 35935291 PMCID: PMC9347968 DOI: 10.1021/acsomega.2c01405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/13/2022] [Indexed: 05/24/2023]
Abstract
Agricultural practices in modern society have a detrimental impact on the health of the ecosystem, environment, and consumers. The significantly high usage rate of chemicals causes serious harm, and the sector demands the development of innovative materials that can foster improved food production and lessen ecological impacts. The majority of layered double hydroxides (LDH) are synthetic. At the same time, some of them occur in the form of natural minerals (hydrotalcite), which have recently emerged as favorable materials and provided advanced and ingenious frontiers in various fields of agriculture through practical application possibilities that can replace conventional agricultural systems. LDH can exchange anions intercalated between the layers in the interlayer structure, and there is evidence that atmospheric carbon dioxide and moisture can completely break down LDH over time. Due to certain unique properties such as tunable structure, specific intercalation chemistry, pH-dependent stability, as well as retention of the guest molecules within interlayers and their subsequent controlled release, LDHs are increasingly investigated as materials to enhance yield, quality of crops, and soil in recent times. This review aims to present the current research progress in the design and development of LDH-based materials as nanoscale agrochemicals to illustrate its relevance in making agro-practices more sustainable and efficient. Specific emphasis is given to the functionality of these materials as effective materials for the slow release of fertilizers and plant growth factors as well as adsorption of toxic agrochemical residues and contaminants. Relevant research efforts have been briefly reviewed, and the potential of LDH as new generation green materials to provide solutions to agricultural problems for improving food productivity and security has been summarized.
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Affiliation(s)
- Abhinandan Singha Roy
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
| | - Sreejarani Kesavan Pillai
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein 2028, Johannesburg, South Africa
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47
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Pulliam JRC, van Schalkwyk C, Govender N, von Gottberg A, Cohen C, Groome MJ, Dushoff J, Mlisana K, Moultrie H. Increased risk of SARS-CoV-2 reinfection associated with emergence of Omicron in South Africa. Science 2022; 376:eabn4947. [PMID: 35289632 PMCID: PMC8995029 DOI: 10.1126/science.abn4947] [Citation(s) in RCA: 448] [Impact Index Per Article: 224.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/09/2022] [Indexed: 12/12/2022]
Abstract
We provide two methods for monitoring reinfection trends in routine surveillance data to identify signatures of changes in reinfection risk and apply these approaches to data from South Africa's severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic to date. Although we found no evidence of increased reinfection risk associated with circulation of the Beta (B.1.351) or Delta (B.1.617.2) variants, we did find clear, population-level evidence to suggest immune evasion by the Omicron (B.1.1.529) variant in previously infected individuals in South Africa. Reinfections occurring between 1 November 2021 and 31 January 2022 were detected in individuals infected in all three previous waves, and there has been an increase in the risk of having a third infection since mid-November 2021.
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Affiliation(s)
- Juliet R. C. Pulliam
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Cari van Schalkwyk
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
| | - Nevashan Govender
- National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
| | - Anne von Gottberg
- National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Cheryl Cohen
- National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Michelle J. Groome
- National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jonathan Dushoff
- South African DSI-NRF Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa
- McMaster University, Hamilton, Ontario, Canada
| | - Koleka Mlisana
- National Health Laboratory Service, Johannesburg, South Africa
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - Harry Moultrie
- National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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48
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Chinomso Iroegbu A, Ray SS. Lignin and Keratin-Based Materials in Transient Devices and Disposables: Recent Advances Toward Materials and Environmental Sustainability. ACS Omega 2022; 7:10854-10863. [PMID: 35415330 PMCID: PMC8991899 DOI: 10.1021/acsomega.1c07372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/07/2022] [Indexed: 05/08/2023]
Abstract
Rising concerns and the associated negative implications of pollution from e-waste and delayed decomposition and mineralization of component materials (e.g., plastics) are significant environmental challenges. Hence, concerted pursuit of accurate and efficient control of the life cycle of materials and subsequent dematerialization in target environments has become essential in recent times. The emerging field of transient technology will play a significant role in this regard to help overcome current environmental challenges by enabling the use of novel approaches and new materials with unique functionalities to produce devices and materials such as disposable diagnostic devices, flexible solar panels, and foldable displays that are more ecologically benign, low-cost, and sustainable. The prerequisites for materials employed in transient devices and disposables include biodegradability, biocompatibility, and the inherent ability to mineralize or dissipate in target environments (e.g., body fluids) in a short lifetime with net-zero impact. Biomaterials such as lignin and keratin are well-known to be among the most promising environmentally benign, functional, sustainable, and industrially applicable resources for transient devices and disposables. Consequently, considering the current environmental concerns, this work focuses on the advances in applying lignin and keratin-based materials in short-life electronics and single-use consumables, current limitations, future research outlook toward materials, and environmental sustainability.
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Affiliation(s)
- Austine
Ofondu Chinomso Iroegbu
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific
& Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doornfontein 2028, Johannesburg, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology Innovation Centre, Council for Scientific
& Industrial Research, Pretoria 0001, South Africa
- ,
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49
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Carter JG, Pfukwa R, Riley L, Tucker JHR, Rodger A, Dafforn TR, Klumperman B. Linear Dichroism Activity of Chiral Poly( p-Aryltriazole) Foldamers. ACS Omega 2021; 6:33231-33237. [PMID: 34901675 PMCID: PMC8656205 DOI: 10.1021/acsomega.1c06139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 05/04/2023]
Abstract
Controllable higher-order assembly is a central aim of macromolecular chemistry. An essential challenge to developing these molecules is improving our understanding of the structures they adopt under different conditions. Here, we demonstrate how flow linear dichroism (LD) spectroscopy is used to provide insights into the solution structure of a chiral, self-assembled fibrillar foldamer. Poly(para-aryltriazole)s fold into different structures depending on the monomer geometry and variables such as solvent and ionic strength. LD spectroscopy provides a simple route to determine chromophore alignment in solution and is generally used on natural molecules or molecular assemblies such as DNA and M13 bacteriophage. In this contribution, we show that LD spectroscopy is a powerful tool in the observation of self-assembly processes of synthetic foldamers when complemented by circular dichroism, absorbance spectroscopy, and microscopy. To that end, poly(para-aryltriazole)s were aligned in a flow field under different solvent conditions. The extended aromatic structures in the foldamer give rise to a strong LD signal that changes in sign and in intensity with varying solvent conditions. A key advantage of LD is that it only detects the large assemblies, thus removing background due to monomers and small oligomers.
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Affiliation(s)
- Jake G. Carter
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
- School
of Biosciences, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
| | - Rueben Pfukwa
- Department
of Chemistry and Polymer Sciences, Stellenbosch
University, Private Bag X1, Matieland 7602, South Africa
| | - Liam Riley
- School
of Biosciences, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
- School
of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.
| | - James H. R. Tucker
- School
of Chemistry, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
| | - Alison Rodger
- Department
of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Timothy R. Dafforn
- School
of Biosciences, University of Birmingham, Edgbaston, Birmingham, West Midlands B15 2TT, U.K.
| | - Bert Klumperman
- Department
of Chemistry and Polymer Sciences, Stellenbosch
University, Private Bag X1, Matieland 7602, South Africa
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50
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Muzata T, Gebrekrstos A, Ray SS. Recent Progress in Modified Polymer-Based PPE in Fight Against COVID-19 and Beyond. ACS Omega 2021; 6:28463-28470. [PMID: 34723042 PMCID: PMC8547166 DOI: 10.1021/acsomega.1c04754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
The increasing concerns about human-health-related microbial infections and the need for the development of personal protective equipment (PPE) is becoming a major challenge. Because of their light weight and ease of processing, polymeric materials are widely used in designing and fabricating PPE that are being used by healthcare workers and the general population. Among the available PPEs, face masks have been widely developed from polymeric materials such as polypropylene, polycarbonate, and poly(ethylene terephthalate). However, currently, many of the face masks are not antimicrobial, which can pose a great risk for cross-infection as discarded masks can be a dangerous source of microbes. To prevent the spread of microbes, researchers have prompted the development of self-sterilizing masks that are capable of inactivating microbes via different mechanisms. Hence, this review provides a brief overview of the currently available antimicrobial-modified polymer-based PPE, and it mainly focuses on the different types of nanoparticles and other materials that have been embedded in different polymeric materials. The possibility of inhaling microplastics from wearing a face mask is also outlined, and the effects of various modifications on the health of face mask users are also explored. Furthermore, the effects of the disposed masks on the environment are underlined.
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Affiliation(s)
- Tanyaradzwa
S. Muzata
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Amanuel Gebrekrstos
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
| | - Suprakas Sinha Ray
- Department
of Chemical Sciences, University of Johannesburg, Doorfontein, Johannesburg 2028, South Africa
- Centre
for Nanostructures and Advanced Materials, DSI-CSIR Nanotechnology
Innovation Centre, Council for Scientific
and Industrial Research, Pretoria 0001, South Africa
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