Antibody longevity and waning following COVID-19 vaccination in a 1-year longitudinal cohort in Bangladesh

COVID-19 vaccines have been effective in preventing severe illness, hospitalization and death, however, the effectiveness diminishes with time. Here, we evaluated the longevity of antibodies generated by COIVD-19 vaccines and the risk of (re)infection in Bangladeshi population. Adults receiving two doses of AstraZeneca, Pfizer, Moderna or Sinopharm vaccines were enrolled at 2-4 weeks after second dosing and followed-up at 4-monthly interval for 1 year. Data on COVID-like symptoms, confirmed COVID-19 infection, co-morbidities, and receipt of booster dose were collected; blood was collected for measuring spike (S)- and nucleocapsid (N)-specific antibodies. S-specific antibody titers reduced by ~ 50% at 1st follow-up visit and continued to decline unless re-stimulated by booster vaccine dose or (re)infection. Individuals infected between follow-up visits showed significantly lower S-antibody titers at preceding visits compared to the uninfected individuals. Pre-enrolment infection between primary vaccination dosing exhibited 60% and 50% protection against reinfection at 5 and 9 months, respectively. mRNA vaccines provided highest odds of protection from (re)infection up to 5 months (Odds Ratio (OR) = 0.08), however, protection persisted for 9 months in AstraZeneca vaccine recipients (OR = 0.06). In conclusion, vaccine-mediated protection from (re)infection is partially linked to elevated levels of S-specific antibodies. AstraZeneca vaccine provided the longest protection.

Assessing the choice of smoke-free policies for multiunit housing and its associated determinants in Bangladesh: a cross-sectional study

OBJECTIVES

This study aimed to assess the desire for smoke-free housing, determine the choice of smoke-free policies for multiunit housing (MUH), and identify the factors associated with policy choice among MUH residents in Bangladesh.

DESIGN

We conducted a cross-sectional study from April to November 2019 using a semi-structured survey questionnaire.

SETTING

This study was conducted in seven divisional cities of Bangladesh: Dhaka, Chattogram, Rajshahi, Khulna, Sylhet, Barishal, and Rangpur.

PARTICIPANTS

A total of 616 adult individuals living in MUH for at least 2 years participated in the study.

PRIMARY OUTCOME MEASURE

Multinomial logistic regression was used to identify the determinants of the choice of smoke-free policies for MUH.

RESULTS

Overall, 94.8% of the respondents wanted smoke-free housing. Among those who wanted smoke-free housing, 44.9% preferred a smoke-free building policy, 28.3% preferred a smoke-free common area policy, 20.2% favoured a smoke-free unit policy, and 6.7% did not know what policy they should choose. Three factors were found to be significantly associated with the choice of a smoke-free building policy: staying at home for more than 12 hours (adjusted OR (aOR): 2.6; 95% CI 1.035 to 6.493), being a non-smoker (aOR: 3.2; 95% CI 1.317 to 7.582), and having at least one family member who smoked (aOR: 3.0; 95% CI 1.058 to 8.422). Results also showed that residents having at least one child under 15 in the family (aOR: 0.3; 95% CI 0.152 to 0.778) were less likely to choose a smoke-free common area policy and that women (aOR: 3.7; 95% CI 1.024 to 13.188) were more likely to choose a smoke-free unit policy.

CONCLUSIONS

MUH residents in urban Bangladesh highly demanded smoke-free housing. Most residents favoured a smoke-free building policy for MUH. Those who stayed at home for a longer time, were non-smokers, and had smoking family members were more likely to choose this policy.

Partial Thermal Condensation Mediated Synthesis of High-Density Nickel Single Atom Sites on Carbon Nitride for Selective Photooxidation of Methane into Methanol

Direct selective transformation of greenhouse methane (CH4) to liquid oxygenates (methanol) can substitute energy-intensive two-step (reforming/Fischer-Tropsch) synthesis while creating environmental benefits. The development of inexpensive, selective, and robust catalysts that enable room temperature conversion will decide the future of this technology. Single-atom catalysts (SACs) with isolated active centers embedded in support have displayed significant promises in catalysis to drive challenging reactions. Herein, high-density Ni single atoms are developed and stabilized on carbon nitride (NiCN) via thermal condensation of preorganized Ni-coordinated melem units. The physicochemical characterization of NiCN with various analytical techniques including HAADF-STEM and X-ray absorption fine structure (XAFS) validate the successful formation of Ni single atoms coordinated to the heptazine-constituted CN network. The presence of uniform catalytic sites improved visible absorption and carrier separation in densely populated NiCN SAC resulting in 100% selective photoconversion of (CH4) to methanol using H2O2 as an oxidant. The superior catalytic activity can be attributed to the generation of high oxidation (NiIII═O) sites and selective C─H bond cleavage to generate •CH3 radicals on Ni centers, which can combine with •OH radicals to generate CH3OH.

Did the COVID-19 pandemic affect levels of burnout, anxiety and depression among doctors and nurses in Bangladesh? A cross-sectional survey study

INTRODUCTION

COVID-19 has caused severe disruption to clinical services in Bangladesh but the extent of this, and the impact on healthcare professionals is unclear. We aimed to assess the perceived levels of anxiety, depression and burnout among doctors and nurses during COVID-19 pandemic.

METHODS

We undertook an online survey using RedCap, directed at doctors and nurses across four institutions in Bangladesh (The Sheikh Russel Gastro Liver Institute & Hospital (SRNGIH), Dhaka Medical College Hospital (DMCH), Mugda Medical College Hospital (MMCH) and M Abdur Rahim Medical College (MARMC) Hospital). We collected information on demographics, awareness of well-being services, COVID-19-related workload, as well as anxiety, depression and burnout using two validated questionnaires: the Hospital Anxiety and Depression Scale (HADS) and the Maslach Burnout Inventory (MBI).

RESULTS

Of the 3000 participants approached, we received responses from 2705 (90.2%). There was a statistically significant difference in anxiety, depression and burnout scores across institutions (p<0.01). Anxiety, depression and burnout scores were statistically worse in COVID-19 active staff compared with those not working on COVID-19 activities (p<0.01 for HADS anxiety and depression and MBI emotional exhaustion (EE), depersonalisation (DP) and personal accomplishment (PA)). Over half of the participants exhibited some level of anxiety (SRNGIH: 52.2%; DMCH: 53.9%; MMCH: 61.3%; MARMC: 68%) with a high proportion experiencing depression (SRNGIH: 39.5%; DMCH: 38.7%; MMCH: 53.7%; MARMC: 41.1%). Although mean burnout scores were within the normal range for each institution, a high proportion of staff (almost 20% in some instances) were shown to be classified as experiencing burnout by their EE, DP and PA scores.

CONCLUSION

We identified a high prevalence of perceived anxiety, depression and burnout among doctors and nurses during the COVID-19 pandemic. This was worse in staff engaged in COVID-19-related activities. These findings could help healthcare organisations to plan for future similar events.

Modulating Cation and Water Transports for Enhanced CO Electrolysis via Ionomer Coating

Electrification of the chemical industry has been considered an enabler for energy transition on a massive scale. In this context, carbon monoxide electroreduction (COR) to produce multi-carbon (C2+ ) products is considered one of the forefront emerging technologies. The key challenge in COR comes from the excessive cation crossover to the cathode via electromigration and water diffusion, which limits CO availability and impedes product selectivity. Commercial anion exchange membrane (AEM) suppresses the electromigration of cations, however, suffers from water diffusion which facilitates cation crossover. Here, we tackled these problems emerging from cation crossover and water diffusion by directly depositing an ultrathin Nafion ionomer on the cathode (sputtered Cu) surface. Our approach enables full-cell energy efficiency of 21 % for converting CO into ethylene (C2 H4 ) at 100 mA/cm2 with over 200 hours of stable operation. We also exhibited record high energy efficiency for ethanol (C2 H5 OH) production with CO-to-C2 H5 OH electrolysis efficiency of 17 %. This approach to directly depositing ultrathin ionomer on the cathode to enhance system performance may benefit other electrochemical systems to overcome challenges associated with scalability, stability, and efficiency to produce high-value chemicals.

Frequency of Post Endoscopic Retrograde Cholangiopancreatography Acute Pancreatitis in an Academic Hospital of Bangladesh

Post-ERCP acute pancreatitis (PEP) is a common and serious complication with high morbidity and mortality rates. There is a paucity of data on the frequency of PEP in a resource constraint setting like Bangladesh. Hence we have conducted a prospective study to determine the frequency of PEP and the factors associated with its occurrence. This prospective, observational study was carried out in Gastroenterology Department of Dhaka Medical College & Hospital, Dhaka, Bangladesh from April 2018 to December 2018 on the consecutive patients who underwent ERCP. PEP and its severity were diagnosed according to consensus definition. Serum lipase was done in all patients before procedure and 24 hours after procedure or if patient develops abdominal pain after the procedure which became earlier. Total 168 patients were included (mean age 46.97±14.35 years; male 72(43.0%). The most common indication of ERCP was choledocholithiasis 97(58.0%) followed by malignant biliary obstruction 45(27.0%), recurrent pyogenic cholangitis 8(5.0%), chronic pancreatitis 4(2.3%), biliary ascariasis 4(2.3%) and others 10(6.0%). Overall post ERCP complication rate was 46(27.3%) including cholangitis 29(17.3%), pancreatitis 16(9.5%), bleeding 12(7.1%), aspiration pneumonia 4(2.4%) and death 3(1.8%). Regarding the severity of PEP, 50.0%, 43.7% and 6.3% patients developed mild, moderate and severe pancreatitis respectively. Number of cannulation attempts >5 times [22(48%) vs. 17(14%); p=0.001], cannulation attempts duration more than 10 minutes [25(55%) vs. 27(22%); p=0.001], unintentional passage of guide wire into the pancreatic duct [8(17%) vs. 18(15%); p=0.001], pancreatic duct contrast injection [12(26%) vs. 2(1.6%); p=0.001] and pre-cut sphincterotomy [16(35%) vs. 6(4.9%); p=0.001] were significantly different between the patients who developed PEP compared to those who did not. In multiple logistic regressions analysis, pancreatic duct contrast injection was significantly associated with PEP [OR 25.523 with 95% CI (4.049- 100.0%)]. Around ten percent patients had developed PEP. Regarding the severity half of them were mild, 44.0% patients had moderate and 6.0% patient had severe type of pancreatitis. Difficult cannulation, unintentional passage of guide wire into the pancreas, pancreatic duct contrast injection and pre-cut sphincterotomy were associated with PEP. Among them pancreatic duct contrast injection had independent significance in the causation of PEP.

Antibody-mediated SARS-CoV-2 entry in cultured cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells by first engaging its cellular receptor angiotensin converting enzyme 2 (ACE2) to induce conformational changes in the virus-encoded spike protein and fusion between the viral and target cell membranes. Here, we report that certain monoclonal neutralizing antibodies against distinct epitopic regions of the receptor-binding domain of the spike can replace ACE2 to serve as a receptor and efficiently support membrane fusion and viral infectivity in vitro. These receptor-like antibodies can function in the form of a complex of their soluble immunoglobulin G with Fc-gamma receptor I, a chimera of their antigen-binding fragment with the transmembrane domain of ACE2 or a membrane-bound B cell receptor, indicating that ACE2 and its specific interaction with the spike protein are dispensable for SARS-CoV-2 entry. These results suggest that antibody responses against SARS-CoV-2 may help expand the viral tropism to otherwise nonpermissive cell types with potential implications for viral transmission and pathogenesis.

A facile synthesis process of GCN/ZnO-Cu nanocomposite and the evaluation of the performance for the photocatalytic degradation of organic pollutants and the disinfection of wastewater under visible light

In this research, graphitic carbon nitride/zinc oxide-copper denoted as GCN/ZnO-Cu nanocomposite photocatalysts were synthesized using a novel facile synthesis process, the co-exfoliation method involving ultrasonic exfoliation of the mixture of GCN and ZnO-Cu in ethanol and then thermal exfoliation. Different characterization techniques such as X-ray diffraction (XRD), mean crystallite size (MCS), BET surface area, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), particle size distribution (PSD), Fourier transform-infrared spectroscopy (FT-IR), photoluminescence (PL) spectra, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were conducted to study the crystallinity, morphology, elemental composition, chemical structure, and optoelectronic properties. The band gap was estimated using the UV-Vis DRS results and Tauc plots. The photocatalytic activity of the GCN/ZnO-Cu3% nanocomposites was evaluated in the degradation of 4-chlorophenol (4-CP), and the disinfection of wastewater primary influent under a narrowband visible light source, royal blue LED (λ = 450 nm). GCN/0.1ZnO-Cu3% nanocomposite showed the best performance in the degradation of 4-CP and the disinfection of municipal wastewater primary influent. For 4-CP degradation, GCN/0.1ZnO-Cu3% was 2.2 times better than GCN, 9.4 times better than ZnO-Cu3%, and 1.8 times better than the sum of the individual GCN and ZnO-Cu3%. A 5.5 log reduction was achieved for the disinfection of total coliforms in wastewater primary influent in 360 min. This enhanced photocatalytic activity of GCN/ZnO-Cu3% nanocomposite can be attributed to the synergistic of GCN and the ZnO-Cu3%, resulting in a large surface area and improved bandgap.

Evaluating the ergonomic deficiencies in computer workstations and investigating their correlation with reported musculoskeletal disorders and visual symptoms among computer users in Bangladeshi university

Nowadays, computer users are facing musculoskeletal disorders (MSDs) and visual symptoms. Prolonged sitting in inappropriate, awkward, and static postures on the computer workstation may cause musculoskeletal disorders (MSDs). Similarly, inappropriate placement of monitors, illumination, and other factors such as prolonged usage of computers are related to visual symptoms.

OBJECTIVE

This study aims to evaluate the ergonomic deficiencies of computer workstations and their correlation with MSDs and visual symptoms.

METHODS

This study involved 271 university employees from a Bangladeshi engineering university. Ergonomic deficiencies were evaluated through direct observations and Occupational Safety and Health Administration checklists. In addition, the Nordic Musculoskeletal Questionnaire was used to assess the prevalence of MSDs and visual discomforts. Binary Logistic Regression (BLR) analysis was also used to examine the correlation between musculoskeletal symptoms and ergonomic deficiencies.

RESULTS

Results showed serious deficiencies in workstation setup, seating arrangement, monitor orientations, keyboard orientations, other input device orientations, and accessory setup. Employees reported that the MSDs in different body regions during the last 12 months including lower back (62 %), upper back (53 %), shoulders (47 %), and neck (25 %). Moreover, itchy eyes (69 %), tired eyes (83 %), and unclear vision (56.83 %) were the most common visual discomforts or visual symptoms among the participants. Results also revealed that monitor ergonomics and its orientation deficits were significantly associated with visual discomforts. Gender, job type, age, BMI, work experience, duration of computer work, and beak taking after 2 h were the independent variables reliably predicting the MSDs and visual symptoms.

CONCLUSION

It is evident that MSDs and visual symptoms were associated with computer workstation deficiencies and other work-related factors.

Towards green economy and sustainable development in Bangladesh: assessing the role of social and environmental indicators

The evolution towards a green economy integrating social, economic, and environmental concerns has opened a new window to pursue the sustainable development goals (SDGs), especially for emerging nations. Nonetheless, despite being a pressing concern on a global scale, empirical research into the potential for green economy development in the context of Bangladesh has remained notably inadequate. To fill this void, this study is an attempt to evaluate the connection among economic growth, carbon dioxide (CO2) emissions, education, life expectancy, and technology to conclude the ecological and socio-economic repercussions of a green economy in Bangladesh's framework of achieving SDGs. Considering the statistical features of the annual data from 1990 to 2019, the autoregressive distributed lag (ARDL) method has been employed to analyze the connections between the chosen variables. The empirical outcomes show that an upsurge in CO2 is accompanied by a 3.66% increase in GDP over the long term, suggesting a positive and statistically significant relationship between the two variables. In addition, GDP increases by about 4.2% for every 1% increase in life expectancy. However, the relationship between technological innovation and education found an insignificant positive linkage with GDP. The most important takeaway from these findings is that the growth of Bangladesh's economy is occurring at the expense of the environment. Hence, this research recommends that, as a developing nation, Bangladesh should concentrate on environment-friendly alternatives, which can be done through the introduction of a green economy to achieve a sustainably developed economy.

Multifunctional carbon nitride nanoarchitectures for catalysis

Catalysis is at the heart of modern-day chemical and pharmaceutical industries, and there is an urgent demand to develop metal-free, high surface area, and efficient catalysts in a scalable, reproducible and economic manner. Amongst the ever-expanding two-dimensional materials family, carbon nitride (CN) has emerged as the most researched material for catalytic applications due to its unique molecular structure with tunable visible range band gap, surface defects, basic sites, and nitrogen functionalities. These properties also endow it with anchoring capability with a large number of catalytically active sites and provide opportunities for doping, hybridization, sensitization, etc. To make considerable progress in the use of CN as a highly effective catalyst for various applications, it is critical to have an in-depth understanding of its synthesis, structure and surface sites. The present review provides an overview of the recent advances in synthetic approaches of CN, its physicochemical properties, and band gap engineering, with a focus on its exclusive usage in a variety of catalytic reactions, including hydrogen evolution reactions, overall water splitting, water oxidation, CO2 reduction, nitrogen reduction reactions, pollutant degradation, and organocatalysis. While the structural design and band gap engineering of catalysts are elaborated, the surface chemistry is dealt with in detail to demonstrate efficient catalytic performances. Burning challenges in catalytic design and future outlook are elucidated.

Biophysical and biochemical nature of amorphous protein oligomers determines the strength of immune response and the generation of T-cell memory

Here, we used domain 3 of dengue virus serotype 3 envelope protein (D3ED3), a natively folded globular low-immunogenicity protein, to ask whether the biophysical nature of amorphous oligomers can affect immunogenicity. We prepared nearly identical 30 ~ 50 nm-sized amorphous oligomers in five distinct ways and looked at any correlation between their biophysical properties and immunogenicity. One oligomer type was produced using our SCP tag (solubility controlling peptide) made of 5 isoleucines (C5I). The others were prepared by miss-shuffling the SS bonds (Ms), heating (Ht), stirring (St) and freeze-thaw (FT). Dynamic light scattering showed that all five formulations contained oligomers of approximately identical sizes with hydrodynamic radii (Rh) between 30 and 55 nm. Circular dichroism (cd) indicated that the secondary structure content of oligomers formed by stirring and freeze-thaw was essentially identical to that of the native monomeric D3ED3. The secondary structure content of the Ms showed moderate changes, whereas the C5I and heat-induced (Ht) oligomers exhibited a significant change. The Ms contained D3ED3 with intermolecular SS bonds as assessed by nonreducing size exclusion chromatography (SEC). Immunization in JcL:ICR mice showed that both C5I and Ms significantly increased the anti-D3ED3 IgG titre. Ht, St and FT were only mildly immunogenic, similar to the monomeric D3ED3. Cell surface CD marker analysis by flow cytometry confirmed that immunization with Ms generated a strong central and effector T-cell memory. Our observations indeed suggest that controlled oligomerization can provide a new, adjuvant-free method for increasing a protein's immunogenicity, yielding a potentially powerful platform for protein-based (subunit) vaccines.

Cooperative Copper Single-Atom Catalyst in 2D Carbon Nitride for Enhanced CO2 Electrolysis to Methane

Renewable-electricity-powered carbon dioxide (CO2 ) reduction (eCO2 R) to high-value fuels like methane (CH4 ) holds the potential to close the carbon cycle at meaningful scales. However, this kinetically staggered 8-electron multistep reduction suffers from inadequate catalytic efficiency and current density. Atomic Cu-structures can boost eCO2 R-to-CH4 selectivity due to enhanced intermediate binding energies (BEs) resulting from favorably shifted d-band centers. In this work, 2D carbon nitride (CN) matrices, viz. Na-polyheptazine (PHI) and Li-polytriazine imides (PTI), are exploited to host Cu-N2 type single-atom sites with high density (≈1.5 at%), via a facile metal-ion exchange process. Optimized Cu loading in nanocrystalline Cu-PTI maximizes eCO2 R-to-CH4 performance with Faradaic efficiency (FECH4 ) of ≈68% and a high partial current density of 348 mA cm-2 at -0.84 V vs reversible hydrogen electrode (RHE), surpassing the state-of-the-art catalysts. Multi-Cu substituted N-appended nanopores in the CN frameworks yield thermodynamically stable quasi-dual/triple sites with large interatomic distances dictated by the pore dimensions. First-principles calculations elucidate the relative Cu-CN cooperative effects between the matrices and how the Cu local environment dictates the adsorbate BEs, density of states, and CO2 -to-CH4 energy profile landscape. The 9N pores in Cu-PTI yield cooperative Cu-Cu sites that synergistically enhance the kinetics of the rate-limiting steps in the eCO2 R-to-CH4 pathway.

Bifunctional Gas Diffusion Electrode Enables In Situ Separation and Conversion of CO2 to Ethylene from Dilute Stream

The requirement of concentrated carbon dioxide (CO₂ ) feedstock significantly limits the economic feasibility of electrochemical CO₂ reduction (eCO₂ R) which often involves multiple intermediate processes, including CO₂ capture, energy-intensive regeneration, compression, and transportation. Herein, a bifunctional gas diffusion electrode (BGDE) for separation and eCO₂ R from a low-concentration CO₂ stream is reported. The BGDE is demonstrated for the selective production of ethylene (C₂ H₄ ) by combining high-density-polyethylene-derived porous carbon (HPC) as a physisorbent with polycrystalline copper as a conversion catalyst. The BGDE shows substantial tolerance to 10 vol% CO₂ exhibiting a Faradaic efficiency of ≈45% toward C₂ H₄ at a current density of 80 mA cm^-2 , outperforming previous reports that utilized such partial pressure (P_CO2 = 0.1 atm and above) and unaltered polycrystalline copper. Molecular dynamics simulation and mixed gas permeability assessment reveal that such selective performance is ensured by high CO₂ uptake of the microporous HPC as well as continuous desorption owing to the molecular diffusion and concentration gradient created by the binary flow of CO₂ and nitrogen (CO₂ |N₂ ) within the sorbent boundary. Based on detailed techno-economic analysis, it is concluded that this in situ process can be economically compelling by precluding the C₂ H₄ production cost associated with the energy-intensive intermediate steps of the conventional decoupled process.

Lignocellulosic biomass valorization via bio-photo/electro hybrid catalytic systems

Lignocellulosic biomass valorization is regarded as a promising approach to alleviate energy crisis and achieve carbon neutrality. Bioactive enzymes have attracted great attention and been commonly applied for biomass valorization owing to their high selectivity and catalytic efficiency under environmentally benign reaction conditions. Same as biocatalysis, photo-/electro-catalysis also happens at mild conditions (i.e., near ambient temperature and pressure). Therefore, the combination of these different catalytic approaches to benefit from their resulting synergy is appealing. In such hybrid systems, harness of renewable energy from the photo-/electro-catalytic compartment can be combined with the unique selectivity of biocatalysts, therefore providing a more sustainable and greener approach to obtain fuels and value-added chemicals from biomass. In this review, we firstly introduce the pros/cons, classifications, and the applications of photo-/electro-enzyme coupled systems. Then we focus on the fundamentals and comprehensive applications of the most representative biomass-active enzymes including lytic polysaccharide monooxygenases (LPMOs), glucose oxidase (GOD)/dehydrogenase (GDH) and lignin peroxidase (LiP), together with other biomass-active enzymes in the photo-/electro- enzyme coupled systems. Finally, we propose current deficiencies and future perspectives of biomass-active enzymes to be applied in the hybrid catalytic systems for global biomass valorization.

High-Density Cobalt Single-Atom Catalysts for Enhanced Oxygen Evolution Reaction

Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metal-support interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of ∼186 m² g^-1) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (η₁₀ at 351 mV; mass activity of 2209 mA mg_Co^-1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.

One-pot sequential cascade reaction for selective gluconic acid production from cellulose photobiorefining

We demonstrate the feasibility of cellulose photobiocatalytic conversion with >75% cellulose conversion and >75% gluconic acid selectivity from converted glucose. This process is realized via a one-pot sequential cascade reaction by cellulase enzymes and a carbon nitride photocatalyst that can realize selective glucose photoreforming into gluconic acid. Cellulase enzymes breakdown cellulose into glucose, which will subsequently be converted into gluconic acid by essential oxidative species (˙O₂^- and ˙OH) via a selective photocatalysis process with simultaneous H₂O₂ formation. This work demonstrates a good example to realize direct cellulose photobiorefining into value-added chemicals via the photo-bio hybrid system.

Ecological footprint in Bangladesh: Identifying the intensity of economic complexity and natural resources

Recent years have seen a spike in the number of academics utilizing the ecological footprint as a stand-in for environmental depletion because of its extensive nature and its ability to capture the worsening of the ecosystem. Thus, this article brings a new effort to analyze the effect of Bangladesh's economic complexity and natural resources on its ecological footprint over a long period, from 1995 to 2018. Using a nonlinear autoregressive distributed lag (NARDL) model, this paper suggests that a more complex economy has a significantly positive effect on ecological footprint over the long term. If the economy is simplified, it has less impact on the environment. For Bangladesh, an increase in economic complexity of 1 unit leads to an ecological footprint increase of 0.13 units, while a drop in economic complexity of 1% causes an ecological footprint decrease of 0.41%. Results also demonstrate that both positive and negative changes in natural resources contribute to rises in environmental quality in Bangladesh, which negatively influences the country's ecological footprint. Quantitatively, a 1% increase in natural resources reduces the ecological footprint by 0.14%, whereas a 1% decrease in resources has the opposite effect, reducing it by 0.59%. In addition, an asymmetric Granger causality test confirms the existence of a unidirectional causal link from ecological footprint to a positive partial sum of natural resources and from a negative partial sum of natural resources to ecological footprint. Finally, the findings point to a two-way causal relationship between the size of an economy's ecological footprint and the complexity of its economy. Policymakers should boost technological advances and lessen operational costs by adopting an innovative Research and development framework and devoting more cash to natural resource policies that promote an adaptable ecological footprint.

Sustainable valorization of asphaltenes via flash joule heating

The refining process of petroleum crude oil generates asphaltenes, which poses complicated problems during the production of cleaner fuels. Following refining, asphaltenes are typically combusted for reuse as fuel or discarded into tailing ponds and landfills, leading to economic and environmental disruption. Here, we show that low-value asphaltenes can be converted into a high-value carbon allotrope, asphaltene-derived flash graphene (AFG), via the flash joule heating (FJH) process. After successful conversion, we develop nanocomposites by dispersing AFG into a polymer effectively, which have superior mechanical, thermal, and corrosion-resistant properties compared to the bare polymer. In addition, the life cycle and technoeconomic analysis show that the FJH process leads to reduced environmental impact compared to the traditional processing of asphaltene and lower production cost compared to other FJH precursors. Thus, our work suggests an alternative pathway to the existing asphaltene processing that directs toward a higher value stream while sequestering downstream emissions from the processing.

Catalyst Regeneration via Chemical Oxidation Enables Long-Term Electrochemical Carbon Dioxide Reduction

Electrochemical CO₂ reduction (ECR) with industrially relevant current densities, high product selectivity, and long-term stability has been a long-sought goal. Unfortunately, copper (Cu) catalysts for producing valuable multicarbon (C₂₊) products undergo structural and morphological changes under ECR conditions, especially at high current densities, resulting in a rapid decrease in product selectivity. Herein, we report a catalyst regeneration strategy, one that employs an electrolysis method comprising alternating "on" and "off" operating regimes, to increase the operating stability of a Cu catalyst. We find that it increases operating lifetime many times, maintaining ethylene selectivity ≥40% for at least 200 h of electrolysis in neutral pH media at a current density of 150 mA cm^-2 using a flow cell. We also demonstrate ECR to ethylene at a current density of 1 A cm^-2 with ethylene selectivity ≥40% using a three-dimensional Cu gas diffusion electrode, finding that this system under these conditions is rendered stable for greater than 36 h. This work illustrates that Cu-based catalysts, once they have entered into the state conventionally considered to possess degraded catalytic activity, may be recovered to deliver high C₂₊ selectivity. We present evidence that the combination of short periods of electrolysis, which minimizes the morphological changes during "on" segments, with the progressive chemical oxidation of Cu atoms on the catalyst surface during "off" segments, united with the added effects of washing the accumulated salt and decreasing the catholyte temperature prolong together the catalyst's operating lifetime.

Single Atom Catalysts for Selective Methane Oxidation to Oxygenates

Direct conversion of methane (CH₄) to C_1-2 liquid oxygenates is a captivating approach to lock carbons in transportable value-added chemicals, while reducing global warming. Existing approaches utilizing the transformation of CH₄ to liquid fuel via tandemized steam methane reforming and the Fischer-Tropsch synthesis are energy and capital intensive. Chemocatalytic partial oxidation of methane remains challenging due to the negligible electron affinity, poor C-H bond polarizability, and high activation energy barrier. Transition-metal and stoichiometric catalysts utilizing harsh oxidants and reaction conditions perform poorly with randomized product distribution. Paradoxically, the catalysts which are active enough to break C-H also promote overoxidation, resulting in CO₂ generation and reduced carbon balance. Developing catalysts which can break C-H bonds of methane to selectively make useful chemicals at mild conditions is vital to commercialization. Single atom catalysts (SACs) with specifically coordinated metal centers on active support have displayed intrigued reactivity and selectivity for methane oxidation. SACs can significantly reduce the activation energy due to induced electrostatic polarization of the C-H bond to facilitate the accelerated reaction rate at the low reaction temperature. The distinct metal-support interaction can stabilize the intermediate and prevent the overoxidation of the reaction products. The present review accounts for recent progress in the field of SACs for the selective oxidation of CH₄ to C_1-2 oxygenates. The chemical nature of catalytic sites, effects of metal-support interaction, and stabilization of intermediate species on catalysts to minimize overoxidation are thoroughly discussed with a forward-looking perspective to improve the catalytic performance.

Post-infection functional gastrointestinal disorders following coronavirus disease-19: A case-control study

BACKGROUND AND AIM

Because acute infectious gastroenteritis may cause post-infection irritable bowel syndrome and functional dyspepsia and the severe acute respiratory syndrome coronavirus-2 affects gastrointestinal (GI) tract, coronavirus disease-19 (COVID-19) may cause post-infection-functional GI disorders (FGIDs). We prospectively studied the frequency and spectrum of post-infection-FGIDs among COVID-19 and historical healthy controls and the risk factors for its development.

METHODS

Two hundred eighty patients with COVID-19 and 264 historical healthy controls were followed up at 1 and 3 months using translated validated Rome Questionnaires for the development of chronic bowel dysfunction (CBD), dyspeptic symptoms, and their overlap and at 6-month for IBS, uninvestigated dyspepsia (UD) and their overlap. Psychological comorbidity was studied using Rome III Psychosocial Alarm Questionnaire.

RESULTS

At 1 and 3 months, 16 (5.7%), 16 (5.7%), 11 (3.9%), and 24 (8.6%), 6 (2.1%), 9 (3.2%) of COVID-19 patients developed CBD, dyspeptic symptoms, and their overlap, respectively; among healthy controls, none developed dyspeptic symptoms and one developed CBD at 3 months (P < 0.05). At 6 months, 15 (5.3%), 6 (2.1%), and 5 (1.8%) of the 280 COVID-19 patients developed IBS, UD, and IBS-UD overlap, respectively, and one healthy control developed IBS at 6 months (P < 0.05 for all except IBS-UD overlap). The risk factors for post-COVID-19 FGIDs at 6 months included symptoms (particularly GI), anosmia, ageusia, and presence of CBD, dyspeptic symptoms, or their overlap at 1 and 3 months and the psychological comorbidity.

CONCLUSIONS

This is the first study showing COVID-19 led to post-COVID-19 FGIDs. Post-COVID-19 FGIDs may pose a significant economic, social, and healthcare burden to the world.

Environmental downfall in Bangladesh: revealing the asymmetric effectiveness of remittance inflow in the presence of foreign aid

Even though remittance inflow in Bangladesh is a significant earning source for recipient individuals and one of the vital factors to the development model, its environmental impacts have been ignored in the empirical investigation. To fill this research gap, this article aims to elucidate the asymmetric effectiveness of remittance inflow on environmental degradation in Bangladesh by addressing foreign aid as an additional multiplier in a carbon dioxide (CO₂) emissions model, a first for this country. This paper, in doing so, utilizes the newly advanced nonlinear autoregressive distributive lag (NARDL) approach. Data examined are yearly observations throughout 1980-2016, and empirically, the results of the NARDL bound test confirm a long-run cointegrated causality between remittance and CO₂ emissions via approving the theoretical linkage. The asymmetric findings interpret that the intensity of CO₂ emissions raises in the long run relative to the positive shock in remittance, while the elasticity of CO₂ emissions is significant and negative due to the negative shock in remittance. The estimation also reveals the presence of a long-run asymmetric association between the variables. In addition, foreign aid is favorable to ameliorate the quality of the environment over a long period. Focusing on the findings, this paper recommends that the government should concentrate on environment favorable projects and also take measures of tax incentives to remittance investors.

Corrosion Resistance of Sulfur-Selenium Alloy Coatings

Despite decades of research, metallic corrosion remains a long-standing challenge in many engineering applications. Specifically, designing a material that can resist corrosion both in abiotic as well as biotic environments remains elusive. Here a lightweight sulfur-selenium (S-Se) alloy is designed with high stiffness and ductility that can serve as an excellent corrosion-resistant coating with protection efficiency of ≈99.9% for steel in a wide range of diverse environments. S-Se coated mild steel shows a corrosion rate that is 6-7 orders of magnitude lower than bare metal in abiotic (simulated seawater and sodium sulfate solution) and biotic (sulfate-reducing bacterial medium) environments. The coating is strongly adhesive, mechanically robust, and demonstrates excellent damage/deformation recovery properties, which provide the added advantage of significantly reducing the probability of a defect being generated and sustained in the coating, thus improving its longevity. The high corrosion resistance of the alloy is attributed in diverse environments to its semicrystalline, nonporous, antimicrobial, and viscoelastic nature with superior mechanical performance, enabling it to successfully block a variety of diffusing species.

Psychometric Properties of the Bengali Version Brief Questionnaire on Smoking Urges (QSU-Brief)

The study aimed to investigate the factorial structure, reliability, and validity of the Bengali version of the brief Questionnaire on Smoking Urges (QSU-Brief) tool in a sample of Bangladeshi smokers. The Bengali version QSU-Brief scale’s reliability and validity were assessed on the basis of the data provided by 460 Bangladeshi smokers. To substantiate the data reliability, internal consistency and test-retest reliability were measured. Exploratory factor analysis (EFA), followed by confirmatory factor analysis (CFA), was conducted to validate the psychometric properties of the 10-item-QSU-Brief tool. The questionnaire showed good internal consistency (Cronbach’s α = 0.94; Intraclass correlation coefficient = 0.91; p<0.001). The EFA and CFA confirmed that a two-factor solution explained 75.1% of the total variance and considered the best item structure of the Bengali version of QSU-Brief across the current study setting. The first factor reflected a strong desire to smoke, which comprised items 1, 2, 3, 5, 6, 9, and 10. While the second factor displayed expectation of relief from the negative implications, which contained items 4, 7, and 8. The study findings showed that the Bengali QSU-Brief had good reliability, validity, and factorial structure. Therefore, this tool could be an excellent candidate to evaluate smoking urges in Bangladeshi settings.

Bioinformatics and system biology approaches to identify pathophysiological impact of COVID-19 to the progression and severity of neurological diseases

The Coronavirus Disease 2019 (COVID-19) still tends to propagate and increase the occurrence of COVID-19 across the globe. The clinical and epidemiological analyses indicate the link between COVID-19 and Neurological Diseases (NDs) that drive the progression and severity of NDs. Elucidating why some patients with COVID-19 influence the progression of NDs and patients with NDs who are diagnosed with COVID-19 are becoming increasingly sick, although others are not is unclear. In this research, we investigated how COVID-19 and ND interact and the impact of COVID-19 on the severity of NDs by performing transcriptomic analyses of COVID-19 and NDs samples by developing the pipeline of bioinformatics and network-based approaches. The transcriptomic study identified the contributing genes which are then filtered with cell signaling pathway, gene ontology, protein-protein interactions, transcription factor, and microRNA analysis. Identifying hub-proteins using protein-protein interactions leads to the identification of a therapeutic strategy. Additionally, the incorporation of comorbidity interactions score enhances the identification beyond simply detecting novel biological mechanisms involved in the pathophysiology of COVID-19 and its NDs comorbidities. By computing the semantic similarity between COVID-19 and each of the ND, we have found gene-based maximum semantic score between COVID-19 and Parkinson's disease, the minimum semantic score between COVID-19 and Multiple sclerosis. Similarly, we have found gene ontology-based maximum semantic score between COVID-19 and Huntington disease, minimum semantic score between COVID-19 and Epilepsy disease. Finally, we validated our findings using gold-standard databases and literature searches to determine which genes and pathways had previously been associated with COVID-19 and NDs.

Frequency of Eosinophilic Esophagitis among Patients with Gastroesophageal Reflux Symptoms in an Academic Hospital of Bangladesh: A Cross Sectional Study

Eosinophilic esophagitis (EoE) is a disease of modern era. It was first described 40 years back. Since then it has drawn an immense interest among the clinicians. It is diagnosed by the presence of eosinophils count ≥15/HPF on esophageal biopsied mucosa in patients with symptoms of esopohageal dysfunction. It is more prevalent among patients with gastroesophageal reflux disease. As its symptoms overlap with that of gastroesophageal reflux disease (GERD), it is frequently overlooked & misdiagnosed which increases patients' sufferings. No data is available in Bangladesh. The objective of the study was to find out the frequency of eosinophilic esophagitis among patients with gastroesophageal reflux symptoms. The study was conducted at the Outpatient department of the department of Gastroenterology of Dhaka Medical College Hospital, Dhaka, Bangladesh from September 2018 to April 2019. One hundred and thirty three (133) consecutive patients with symptoms suggestive of gastroesophageal reflux disease based on validated questionnaire underwent upper GI endoscopy. Biopsies were taken from proximal and distal esophagus as well as any other endoscopically abnormal esophageal mucosal lesion. Among 133 patients with gastroesophageal reflux symptoms, 7 patients (5.3%) were found to be positive for eosinophilic esophagitis. Mean age at diagnosis was 37.28±13.38 years. It was more common in younger age group. Female patients (56%) were more than male patients (44%). Heart burn was the major symptom followed by acid regurgitation. Nocturnal cough showed statistically significant relationship with eosinophilic esophagitis. Although the frequency is low, it may be considered as a differential diagnosis among patients with GERD.

Solubility Controlling Peptide Tags of Opposite Charges Generate a Bivalent Immune Response Against Dengue ED3 Serotypes 3 and 4

We previously demonstrated that a protein’s immunogenicity could be substantially increased by attaching a hydrophobic solubility controlling peptide tag (SCP-tag) producing small sub-visible aggregates. Here, we report the oligomerization of Dengue envelop protein domain 3 (ED3), and consequently, its immunogenicity increase by mixing ED3s attached with SCP-tags of opposite charges at equimolar concentration. We used ED3 of serotype 3 (D3ED3) and serotype 4 (D4ED3), which are, respectively, moderately and poorly immunogenic, and their SCP tagged variants constructed by attaching either a C-termini 5-Aspartic acid (C5D) or a 5-Lysine (C5K) tag. Light scattering indicated that the isolated tagged ED3s remained monomeric, but mixing the C5D and C5K tagged ED3s at equimolar concentration generated sub-visible aggregates or oligomers of ~500 nm through electrostatic interaction. In addition, the oligomerized ED3s remained in a native-like state, as assessed by fluorescence spectroscopy and circular dichroism. The in vivo immunogenicity of the D3ED3 and D4ED3 oligomers generated by the charged tags increased by 5 and 16 fold, respectively. Furthermore, injection of heterotypic ED3 oligomers (D3C5D+D4C5K) induced an immune response against both D3ED3 and D4ED3 in 3 of 4 responsive mice, and the IgG titer of the bivalent anti-D3C5D-D4C5K sera was over 100 times higher than that generated by co-injecting the untagged D3ED3 and D4ED3 (D3+D4). Altogether, these observations suggest that SCP-tags could be used as a platform for producing a long-sought tetravalent dengue vaccine.

EGFR extracellular domain III expressed in Escherichia coli with SEP tag shows improved biophysical and functional properties and generate anti-sera inhibiting cancer cell growth

The epidermal growth factor receptor extracellular domain III (EGFR-ECDIII) protein is a promising target of anti-cancer research, and its production in Escherichia coli would thus represent significant benefits. However, despite its moderate size (19 kDa), the expression of EGFR-ECDIII in E.coli is hampered by the presence of multiple cysteines producing misfolded proteins with incorrect S-S bonds. In our study, we show that a short 12-residue solubility enhancing peptide (SEP) tag containing nine arginines (C9R) attached at the C-terminus of EGFR-ECDIII reduces the inclusion body formation and increases the final yield by six times (20 mg/L). EGFR-ECDIII-C9R purified from the soluble fraction eluted as a sharp single RP-HPLC peak, suggesting a single S-S bond pairing. Biophysical characterization using circular dichroism, fluorescence, and light scattering confirmed its native-like properties together with reversible thermal denaturation. The binding activity of EGFR-ECDIII-C9R to anti-EGFR-VHH7D12, a single-domain antibody with specific binding to the ECDIII, was assessed by sandwich ELISA. Further, we produced anti-EGFR-ECDIII-C9R antisera in mouse models and anti-sera inhibited A431 cancer cells' growth. These results demonstrate that the SEP tag enables the rapid production of the multiple disulfide-bonded EGFR-ECDIII in E. coli having native-like biophysical properties and producing neutralizing antibodies.

Immune response with long-term memory triggered by amorphous aggregates of misfolded anti-EGFR VHH-7D12 is directed against the native VHH-7D12 as well as the framework of the analogous VHH-9G8

We previously demonstrated that amorphous aggregates of misfolded V_HH-7D12 antibodies (V_HH-Mis), a potential anti-EGFR drug, can generate a robust serum IgG response. Here we investigate the immunogenic nature, especially the specificity of the immune response induced by V_HH-Mis. To this end, we used two natively folded and 77% identical anti-EGFR V_HHs (V_HH-7D12 and V_HH-9G8) that possess a common framework but distinct complementarity determining regions (CDRs). In 60% of mice immunized with V_HH-Mis, the anti-V_HH-7D12 IgG titer was stronger than the anti-V_HH-9G8 titer (Group-1). In the remaining mice (40%; Group-2), the anti-V_HH-7D12 and anti-V_HH-9G8 titer were almost identical. We rationalized these results by hypothesizing that mice in Group-1 produced IgG mostly against the V_HH-7D12's CDRs, whereas in Group-2 mice, they targeted the V_HH's framework. The IgG specificity against V_HH-7D12 and V_HH-9G8 was essentially unchanged over 17 weeks in both groups. Further, in all mice (Group-1&2) re-immunized with native V_HH-7D12, the IgG titer against V_HH-7D12 increased sharply but not against V_HH-9G8. On the other hand, none of the three Group-1 mice re-immunized with native V_HH-9G8 showed immunogenicity against V_HH-7D12 nor V_HH-9G8. Whereas, in Group-2 mice (three/three) re-immunized with V_HH-9G8, the IgG titers against both V_HHs increased but slowly. Flow-cytometric studies showed that V_HH-Mis immunized mice generated a higher number of effector and central memory T-cells. Overall, these observations indicate that amorphous aggregates made of a misfolded V_HH can induce serum IgG against its natively folded self and analogous V_HHs having a similar framework but distinct CDRs. Furthermore, a robust long-term immune response with memory was established against its natively folded self but with a nil-to-moderate immune response against natively folded V_HH analogs.

The Role of National Specialist Societies in Influencing Transformational Change in Low-Middle Income Countries - Reflections on the Model of Implementation for a National Endoscopy Training Programme in Bangladesh

The British Society of Gastroenterology (BSG) and the Bangladesh Gastroenterology Society (BGS) have collaborated on an endoscopy training programme, which has grown up over the past decade from a small scheme borne out of the ideas of consultant gastroenterologists in Swansea, South Wales (United Kingdom) to improve gastroenterology services in Bangladesh to become a formalised training programme with broad reach. In this article, we document the socioeconomic and historical problems that beset Bangladesh, the current training needs of doctors and how the BSG-BGS collaboration has made inroads into changing outcomes both for gastroenterologists in Bangladesh, but also for the populations they serve.

Coproduction of hydrogen and lactic acid from glucose photocatalysis on band-engineered Zn1-xCdxS homojunction

Photocatalytic transformation of biomass into value-added chemicals coupled with co-production of hydrogen provides an explicit route to trap sunlight into the chemical bonds. Here, we demonstrate a rational design of Zn_1-xCd_xS solid solution homojunction photocatalyst with a pseudo-periodic cubic zinc blende (ZB) and hexagonal wurtzite (WZ) structure for efficient glucose conversion to simultaneously produce hydrogen and lactic acid. The optimized Zn_0.6Cd_0.4S catalyst consists of a twinning superlattice, has a tuned bandgap, and displays excellent efficiency with respect to hydrogen generation (690 ± 27.6 μmol·h⁻¹·g_cat.⁻¹), glucose conversion (~90%), and lactic acid selectivity (~87%) without any co-catalyst under visible light irradiation. The periodic WZ/ZB phase in twinning superlattice facilitates better charge separation, while superoxide radical (⋅O₂^-) and photogenerated holes drive the glucose transformation and water oxidation reactions, respectively. This work demonstrates that rational photocatalyst design could realize an efficient and concomitant production of hydrogen and value-added chemicals from glucose photocatalysis.

•

Zn_1-xCd_xS ZB-WZ homojunction was designed to improve charge separation efficiency

•

Bandgap engineering improved the hydrogen production from glucose photoreforming

•

Optimized Zn_0.6Cd_0.4S ZB-WZ exhibited high lactic acid yield and selectivity

•

Rational photocatalyst design realizes biomass valorization and H₂ coproduction

Electropolymerized metal-protoporphyrin electrodes for selective electrochemical reduction of CO2

Developing catalysts that exhibit high efficiencies for the electrochemical CO₂ reduction reaction (CO₂RR) in aqueous media is vital both for a healthier environment and practical implementation to produce value-added fuels from energy waste.

Prevalence, risk factors and metabolic profile of the non-obese and obese non-alcoholic fatty liver disease in a rural community of South Asia

Introduction

Since there is a paucity of data on the epidemiology of the non-alcoholic fatty liver disease (NAFLD), particularly in rural areas in Asia, we undertook such a study among the population of a rural community in Bangladesh with the aims to (1) determine the prevalence of non-obese and obese NAFLD, (2) compare the sociodemographic clinical and metabolic characteristics between non-obese and obese NAFLD subjects, and (3) determine the risk factors of NAFLD and no-nobese NAFLD.

Methods

In this door-to-door survey, clinical examination, anthropometric measurements, biochemical tests and ultrasonography were performed on the adult population (≥18 years) of three villages in Bangladesh.

Results

Of 1682, 1353 (80.44%) responded. After the exclusion of 48 subjects for alcohol consumption, HBsAg or anti-hepatitis C virus positivity, 1305 ((mean age 41.28±15.10 years, female 908 (69.6%)) were included in the final analysis. On ultrasonography, among the study population, 57 (4.4%) non-obese, 185 (14.2%) obese and, overall, 242 (18.5 %, (male 23.40%, female 16.4%, p=0. 003)) participants had NAFLD. NAFLD was detected in 57/804 (7.1%) of non-obese and 185/501 (36.93%) obese participants. Among the lean subjects, 24/592 (4.1%) had NAFLD. Among NAFLD subjects, 57 (23.55%) were non-obese, and 53 (22%) had raised alanine aminotransferase. On multivariate analysis, age >40 years, male gender, metabolic syndrome (MS), diabetes mellitus (DM), abdominal obesity, hypertension, dyslipidaemia and obesity were found as the risk factors for NAFLD. There were no differences in sociodemographic characteristics, DM, MS, abdominal obesity, hypertension and dyslipidaemia between non-obese and obese NAFLD (all p>0.05).

Conclusion

In this community study in Bangladesh, NAFLD was present in 18.5% participants, one-quarter of whom were non-obese. Apart from body mass index, the metabolic profile was comparable between obese and non-obese NAFLD. Public health measures are needed to control and prevent NAFLD and MS and their adverse health consequences.

n-p Heterojunction of TiO2-NiO core-shell structure for efficient hydrogen generation and lignin photoreforming

Hydrogen evolution from biomass photoreforming has been widely recognized as a promising strategy for relieving the pressure from energy crisis and environmental pollution, as it could generate sustainable H₂ and value-added bioproducts simultaneously. Combining p-type semiconductors with n-type semiconductors to form n-p heterojunction is an effective strategy to improve the photocatalytic quantum efficiency by enhancing the separation of photogenerated electrons and holes, which could greatly facilitate the realization of such biomass photorefinery concept. However, the incompact contact between the n-type and p-type semiconductors often induces the aggregation of photogenerated electrons and holes. In this work, we design and synthesize an ultrafine n-p heterojunction TiO₂-NiO core-shell structure to overcome the incompact contact in the n-p interface. When the n-p heterojunction photocatalysts are evaluated for photocatalytic water splitting and biomass lignin photoreforming respectively, the as-fabricated TiO₂-NiO nanocomposite with 3.25% NiO demonstrates the highest hydrogen generation of 23.5 mmol h^-1 g^-1 from water splitting and H₂ (0.45 mmol h^-1 g^-1) and CH₄ (0.03 mmol h^-1 g^-1) cogeneration with reasonable amount of fatty acids (palmitic acid and stearic acid) production from lignin photoreforming. The excellent photocatalytic activity is ascribed to the synergistic effects of high crystallinity of TiO₂ ultrafine nanoparticles, core-shell structure and n-p heterojunction with NiO nanoclusters. This present work demonstrates a simple and efficient method to fabricate ultrafine n-p heterojunction core-shell structure for noble-metal free catalyst for both water splitting and biomass photoreforming.

Reversible Oligomerization and Reverse Hydrophobic Effect Induced by Isoleucine Tags Attached at the C-Terminus of a Simplified BPTI Variant

Protein amorphous aggregation has become the focus of great attention, as it can impair the ability of cells to function properly. Here, we evaluated the effects of three peptide tags, consisting of one, three, and five consecutive isoleucines attached at the C-terminus end of a simplified bovine pancreatic trypsin inhibitor (BPTI) variant, BPTI-19A, on the thermal stability and oligomerization by circular dichroism spectrometry and differential scanning calorimetry in detail. All of the BPTI-19A variants exhibited a reversible and apparently two-state thermal transition like BPTI-19A at pH 4.7. The thermal transition of the five-isoleucine-tagged variant showed clear protein-concentration dependence, where the apparent denaturation temperature decreased as the protein concentration increased. Quantitative analysis indicated that this phenomenon originated from the presence of reversibly oligomerized (RO) states at high temperatures. The results also illustrated that the thermodynamic stability difference between the native and the monomeric denatured state in all the proteins was destabilized by the hydrophobic tags and was well explained by the reverse hydrophobic effect due to the tags. The existence of the RO states was confirmed by both analytical ultracentrifugation and dynamic light scattering. This indicated that the five-isoleucine hydrophobic tag is strong enough to induce intermolecular hydrophobic contact among the denatured molecules leading to oligomerization, and even one- or three-isoleucine tags are effective enough to generate intramolecular hydrophobic contact, thus provoking denaturation through the reverse hydrophobic effect.

A systematic mutational analysis identifies a 5-residue proline tag that enhances the in vivo immunogenicity of a non-immunogenic model protein

Poor immunogenicity of small proteins is a major hurdle in developing vaccines or producing antibodies for biopharmaceutical usage. Here, we systematically analyzed the effects of 10 solubility controlling peptide tags (SCP‐tags) on the immunogenicity of a non‐immunogenic model protein, bovine pancreatic trypsin inhibitor (BPTI‐19A; 6 kDa). CD, fluorescence, DLS, SLS, and AUC measurements indicated that the SCP‐tags did not change the secondary structure content nor the tertiary structures of the protein nor its monomeric state. ELISA results indicated that the 5‐proline (C5P) and 5‐arginine (C5R) tags unexpectedly increased the IgG level of BPTI‐19A by 240‐ and 73‐fold, respectively, suggesting that non‐oligomerizing SCP‐tags may provide a novel method for increasing the immunogenicity of a protein in a highly specific manner.

The immunogenicity of an anti-EGFR single domain antibody (VHH) is enhanced by misfolded amorphous aggregation but not by heat-induced aggregation

Amorphous aggregates of therapeutic proteins can provoke an unwanted immune response (anti-drug antibodies; ADAs), but counter-examples have led to some controversy. Amorphous aggregates can possess unique biophysical and biochemical attributes depending on both the way they are generated and the protein's biophysical/biochemical properties. Here, we examine the immunogenicity of an anti-EGFR single domain antibody (V_HH) in four types of amorphous aggregates: two heat-aggregated V_HH incubated at 65 °C (V_HH-65) and 95 °C (V_HH-95), a misfolded V_HH isolated from the insoluble fraction of the E. coli lysate (V_HH-Ins), and a low solubility misfolded V_HH produced by miss-shuffling the SS bonds of the native V_HH (V_HH-Mis). Biophysical and biochemical measurements indicated that V_HH was indeed natively folded, monomeric, and β-sheeted; that V_HH-65 was partially unfolded and formed aggregates with a Z-average (Zave) of 771 nm; whereas V_HH-95 was unfolded and formed aggregates of 1722 nm; and that both V_HH-Ins and V_HH-Mis were misfolded with non-native intermolecular SS bonds and formed aggregates with a Zave of 1846 nm and 1951 nm, respectively. The IgG level generated in Jcl:ICR mice determined by ELISA showed that the native V_HH was barely immunogenic, V_HH-95 was not immunogenic, while V_HH-65 was mildly immunogenic. By contrast, the misfolded aggregates, V_HH-Ins and V_HH-Mis, having a Zave and an aggregation propensity similar to that of V_HH-95, were highly immunogenic. These findings indicate the critical role of the biochemical and biophysical attributes of the amorphous aggregates in generating an immune response against a protein, rather than just their sizes.

Maternal profiles and social determinants of severe acute malnutrition among children under-five years of age: A case-control study in Nepal

Background

Addressing the determinants of severe acute malnutrition (SAM) among children remains a challenge in Nepal. This study investigated the effect of maternal and social determinants of SAM among under-five children of Nepal.

Methods

We conducted a hospital-based unmatched case-control study with 256 under-five children (128 cases and 128 controls). The children aged 6–59 months were taken, and the cases and controls were defined based on mid-upper arm circumference (MUAC).

Results

Backward Stepwise logistic regression analysis of 6–59 months children showed that the odds of SAM were lower among male children (AOR = 0.50, 95% CI = 0.27–0.92), mothers from high socioeconomic status (AOR = 0.469, 95% CI = 0.26–0.83), breastfeeding 6–12 months (AOR = 0.21, 95% CI = 0.05–0.68), breastfeeding ≥13 months (AOR = 0.18, 95% CI = 0.05–0.54) and optimal complementary feeding (AOR = 0.40, 95% CI = 0.22–0.70). SAM was significantly higher among children of the age group 6–24 months (AOR = 2.57, 95% CI = 1.30–5.22) and children with a history of diarrhea (AOR = 1.75, 95% CI = 0.92–3.39).

Conclusions

In order to reduce the children's SAM, it is necessary to scale up services to improve the socioeconomic status which includes the education, occupation, and monthly income of the mother. Girls of age group 6–24 months were more likely to develop SAM. Two contributing factors to decrease SAM are the importance of exclusive breastfeeding practices and the availability and usage of soap in hand washing, which are ideal for low cost interventions. To reduce SAM in Nepal, a focus on enhancing complementary feeding through increased affordability of nutritious foods is also needed.

Low Rank and Sparse Decomposition of Ultrasound Color Flow Images for Suppressing Clutter in Real-Time

In this work, a novel technique for real-time clutter rejection in ultrasound Color Flow Imaging (CFI) is proposed. Suppressing undesired clutter signal is important because clutter prohibits an unambiguous view of the vascular network. Although conventional eigen-based filters are potentially efficient in suppressing clutter signal, their performance is highly dependent on proper selection of a clutter to blood boundary which is done manually. Herein, we resolve this limitation by formulating the clutter suppression problem as a foreground-background separation problem to extract the moving blood component. To that end, we adapt the fast Robust Matrix Completion (fRMC) algorithm, and utilize the in-face extended Frank-Wolfe method to minimize the rank of the matrix of ultrasound frames. Our method automates the clutter suppression process, which is critical for clinical use. We name the method RAPID (Robust mAtrix decomPosition for suppressIng clutter in ultrasounD) since the automation step can substantially streamline clutter suppression. The technique is validated with simulation, flow phantom and two sets of in-vivo data. RAPID code as well as most of the data in this paper can be downloaded from RAPID.sonography.ai.

Metal-free photocatalysts for hydrogen evolution

This article provides a comprehensive review of the latest progress, challenges and recommended future research related to metal-free photocatalysts for hydrogen productionviawater-splitting.

Electrochemical CO2 Reduction into Chemical Feedstocks: From Mechanistic Electrocatalysis Models to System Design

The electrochemical reduction of CO₂ is a promising route to convert intermittent renewable energy to storable fuels and valuable chemical feedstocks. To scale this technology for industrial implementation, a deepened understanding of how the CO₂ reduction reaction (CO₂ RR) proceeds will help converge on optimal operating parameters. Here, a techno-economic analysis is presented with the goal of identifying maximally profitable products and the performance targets that must be met to ensure economic viability-metrics that include current density, Faradaic efficiency, energy efficiency, and stability. The latest computational understanding of the CO₂ RR is discussed along with how this can contribute to the rational design of efficient, selective, and stable electrocatalysts. Catalyst materials are classified according to their selectivity for products of interest and their potential to achieve performance targets is assessed. The recent progress and opportunities in system design for CO₂ electroreduction are described. To conclude, the remaining technological challenges are highlighted, suggesting full-cell energy efficiency as a guiding performance metric for industrial impact.

Does open-beach ship-breaking affect the mineralogical composition of soil more adversely than typical industrial activities?

In Bangladesh, India, and Pakistan the ship breaking (SB) sector dismantles end-of-life ships on open beaches, exposing the environment to the resulting pollution, especially the soil and water. Because SB occurs in the vicinity of other poorly-regulated activities in industrial zones (IZ) in these countries, there is some ambiguity concerning the relative roles played by SB and IZ in the accumulation of hazardous materials in the soil. In the absence of comparative studies, this study investigated the relative levels of soil contamination due to SB or IZ in the same geographic region by taking soil samples from SB and unrelated IZs in Chittagong, Bangladesh. The technogenic input of sixty-four chemical elements into the soil at the SB or IZ were compared with off-site reference values or the natural content of these elements in the Earth's crust and surface. The magnitude of soil contamination by ecotoxic elements, the corresponding bioavailability, and the ecological risks were assessed based on the regulatory reference values (RRVs) and with other approaches using data aggregation. Among the different potentially toxic elements, Cr, Cu, Ni, Pb, and Zn were found to be above the maximum allowable concentration (p < 0.05) in both SB and IZ. Moderate-to-high soil contamination from SB and moderate-to-considerable soil contamination in the IZ were observed. However, the element-bioavailability as ascertained via solid-phase speciation or weak-acid induced leaching, and the evaluation of associated ecological risk both indicated a low hazard quotient for soils from both SB and IZ. The outcome of the current research marked both SB and IZ soils as contaminated but not polluted, yet remediation is suggested. The level of contamination in SB soils was relatively higher than that of IZ. The comparative results presented in this study for the first time will hopefully be useful as a reference for future ecological and geochemical studies concerning the environmental contamination associated with both ship recycling on open beaches and other typical industrial activities.