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Ramaboli MC, Ocvirk S, Khan Mirzaei M, Eberhart BL, Valdivia-Garcia M, Metwaly A, Neuhaus K, Barker G, Ru J, Nesengani LT, Mahdi-Joest D, Wilson AS, Joni SK, Layman DC, Zheng J, Mandal R, Chen Q, Perez MR, Fortuin S, Gaunt B, Wishart D, Methé B, Haller D, Li JV, Deng L, Swart R, O'Keefe SJD. Diet changes due to urbanization in South Africa are linked to microbiome and metabolome signatures of Westernization and colorectal cancer. Nat Commun 2024; 15:3379. [PMID: 38643180 PMCID: PMC11032404 DOI: 10.1038/s41467-024-46265-0] [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: 07/13/2023] [Accepted: 02/15/2024] [Indexed: 04/22/2024] Open
Abstract
Transition from traditional high-fiber to Western diets in urbanizing communities of Sub-Saharan Africa is associated with increased risk of non-communicable diseases (NCD), exemplified by colorectal cancer (CRC) risk. To investigate how urbanization gives rise to microbial patterns that may be amenable by dietary intervention, we analyzed diet intake, fecal 16 S bacteriome, virome, and metabolome in a cross-sectional study in healthy rural and urban Xhosa people (South Africa). Urban Xhosa individuals had higher intakes of energy (urban: 3,578 ± 455; rural: 2,185 ± 179 kcal/d), fat and animal protein. This was associated with lower fecal bacteriome diversity and a shift from genera favoring degradation of complex carbohydrates (e.g., Prevotella) to taxa previously shown to be associated with bile acid metabolism and CRC. Urban Xhosa individuals had higher fecal levels of deoxycholic acid, shown to be associated with higher CRC risk, but similar short-chain fatty acid concentrations compared with rural individuals. Fecal virome composition was associated with distinct gut bacterial communities across urbanization, characterized by different dominant host bacteria (urban: Bacteriodota; rural: unassigned taxa) and variable correlation with fecal metabolites and dietary nutrients. Food and skin microbiota samples showed compositional differences along the urbanization gradient. Rural-urban dietary transition in South Africa is linked to major changes in the gut microbiome and metabolome. Further studies are needed to prove cause and identify whether restoration of specific components of the traditional diet will arrest the accelerating rise in NCDs in Sub-Saharan Africa.
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Affiliation(s)
- M C Ramaboli
- African Microbiome Institute, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - S Ocvirk
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Intestinal Microbiology Research Group, German Institute of Human Nutrition, Potsdam, Germany
- ZIEL - Institute for Food and Health, Technical University of Munich, Freising, Germany
| | - M Khan Mirzaei
- Institute of Virology, Helmholtz Centre Munich - German Research Centre for Environmental Health, Neuherberg, Germany
- Chair of Microbial Disease Prevention, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - B L Eberhart
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Valdivia-Garcia
- Section of Nutrition, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
| | - A Metwaly
- Chair of Nutrition and Immunology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - K Neuhaus
- Core Facility Microbiome, ZIEL - Institute for Food and Health, Technical University of Munich, Freising, Germany
| | - G Barker
- Section of Nutrition, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
| | - J Ru
- Institute of Virology, Helmholtz Centre Munich - German Research Centre for Environmental Health, Neuherberg, Germany
- Chair of Microbial Disease Prevention, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - L T Nesengani
- Department of Agriculture and Animal Health, University of South Africa, Pretoria, South Africa
| | - D Mahdi-Joest
- Intestinal Microbiology Research Group, German Institute of Human Nutrition, Potsdam, Germany
| | - A S Wilson
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - S K Joni
- Department of Nutrition and Dietetics, School of Public Health, University of the Western Cape, Cape Town, South Africa
| | - D C Layman
- Department of Nutrition and Dietetics, School of Public Health, University of the Western Cape, Cape Town, South Africa
| | - J Zheng
- The Metabolomics Innovation Centre & Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - R Mandal
- The Metabolomics Innovation Centre & Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Q Chen
- Section of Nutrition, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
| | - M R Perez
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - S Fortuin
- African Microbiome Institute, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - B Gaunt
- Zithulele Hospital, Mqanduli District, Mqanduli, Eastern Cape Province, South Africa
| | - D Wishart
- The Metabolomics Innovation Centre & Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - B Methé
- Center for Medicine and the Microbiome, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - D Haller
- ZIEL - Institute for Food and Health, Technical University of Munich, Freising, Germany
- Chair of Nutrition and Immunology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - J V Li
- Section of Nutrition, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, UK
| | - L Deng
- Institute of Virology, Helmholtz Centre Munich - German Research Centre for Environmental Health, Neuherberg, Germany
- Chair of Microbial Disease Prevention, School of Life Sciences, Technical University of Munich, Freising, Germany
| | - R Swart
- Department of Nutrition and Dietetics, School of Public Health, University of the Western Cape, Cape Town, South Africa
| | - S J D O'Keefe
- African Microbiome Institute, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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Bista SS, Li DB, Awni RA, Song Z, Subedi KK, Shrestha N, Rijal S, Neupane S, Grice CR, Phillips AB, Ellingson RJ, Heben M, Li JV, Yan Y. Effects of Cu Precursor on the Performance of Efficient CdTe Solar Cells. ACS Appl Mater Interfaces 2021; 13:38432-38440. [PMID: 34347421 DOI: 10.1021/acsami.1c11784] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Copper (Cu) incorporation is a key process for fabricating efficient CdTe-based thin-film solar cells and has been used in CdTe-based solar cell module manufacturing. Here, we investigate the effects of different Cu precursors on the performance of CdTe-based thin-film solar cells by incorporating Cu using a metallic Cu source (evaporated Cu) and ionic Cu sources (solution-processed cuprous chloride (CuCl) and copper chloride (CuCl2)). We find that ionic Cu precursors offer much better control in Cu diffusion than the metallic Cu precursor, producing better front junction quality, lower back-barrier heights, and better bulk defect property. Finally, outperforming power conversion efficiencies of 17.2 and 17.5% are obtained for devices with cadmium sulfide and zinc magnesium oxide as the front window layers, respectively, which are among the highest reported CdTe solar cells efficiencies. Our results suggest that an ionic Cu precursor is preferred as the dopant to fabricate efficient CdTe thin-film solar cells and modules.
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Affiliation(s)
- Sandip S Bista
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Deng-Bing Li
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Rasha A Awni
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Zhaoning Song
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Kamala K Subedi
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Niraj Shrestha
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Suman Rijal
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Sabin Neupane
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Corey R Grice
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Adam B Phillips
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Randy J Ellingson
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Michael Heben
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
| | - Jian V Li
- Department of Aeronautics and Astronautics, National Cheng Kung University, 70101 Tainan, Taiwan
| | - Yanfa Yan
- Department of Physics and Astronomy, and Wright Center for Photovoltaics Innovation and Commercialization (PVIC), University of Toledo, Toledo, Ohio 43606, United States
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Li JV. Defect characterization by differential capacitance spectroscopy without the Arrhenius plot. Rev Sci Instrum 2021; 92:043903. [PMID: 34243409 DOI: 10.1063/5.0047128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/20/2021] [Indexed: 06/13/2023]
Abstract
A new method of Arrhenius transformation and matching is developed in this study based on the rate-temperature duality of the admittance spectroscopy measurement to extract the activation energy Ea and the attempt-to-escape frequency ν0 of a defect in GaAsN from differential capacitance spectroscopy without the Arrhenius plot and without identifying the fdC/df spectra peaks. The method consists of a set of variations that transform the iso-rate scan and/or the isothermal scan to a virtual space-activation energy, attempt-to-escape frequency, temperature, or rate. The transformed scans must be matched prior to extracting Ea and ν0 local to a fixed point in the two-dimensional temperature-rate experimental space.
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Affiliation(s)
- Jian V Li
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan
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4
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Li JV. Deep level transient spectroscopy characterization without the Arrhenius plot. Rev Sci Instrum 2021; 92:023902. [PMID: 33648155 DOI: 10.1063/5.0039555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
Defect characterization by deep level transient spectroscopy (DLTS) requires the extraction of two key quantities of the carrier emission rate from the defects-activation energy (Ea) and pre-exponential factor (ν0)-the latter is related to the carrier capture cross section. This task, ubiquitous to thermally activated processes besides defect-carrier interaction, is traditionally accomplished by constructing an Arrhenius plot with DLTS peak locations and fitting it with a line. We present a transformation method based on the Arrhenius equation that extracts Ea and ν0without constructing or line-fitting the Arrhenius plot and bypasses peak identification. This method is developed on the basis of the fundamental temperature-rate duality relationship and extracts Ea and ν0 by matching the curvatures the Arrhenius-transformed spectra of the iso-thermal and iso-rate DLTS scans in the 2D temperature-rate plane. The extraction can be conducted with data in a small temperature range and is, therefore, capable of unambiguously resolving Ea and ν0 at any temperature point and their temperature dependence, if any.
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Affiliation(s)
- Jian V Li
- Department of Aeronautics and Astronautics, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
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5
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Neal AT, Mou S, Lopez R, Li JV, Thomson DB, Chabak KD, Jessen GH. Incomplete Ionization of a 110 meV Unintentional Donor in β-Ga 2O 3 and its Effect on Power Devices. Sci Rep 2017; 7:13218. [PMID: 29038456 PMCID: PMC5643349 DOI: 10.1038/s41598-017-13656-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/13/2017] [Indexed: 11/20/2022] Open
Abstract
Understanding the origin of unintentional doping in Ga2O3 is key to increasing breakdown voltages of Ga2O3 based power devices. Therefore, transport and capacitance spectroscopy studies have been performed to better understand the origin of unintentional doping in Ga2O3. Previously unobserved unintentional donors in commercially available \documentclass[12pt]{minimal}
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\begin{document}$$(\bar{2}01)$$\end{document}(2¯01) Ga2O3 substrates have been electrically characterized via temperature dependent Hall effect measurements up to 1000 K and found to have a donor energy of 110 meV. The existence of the unintentional donor is confirmed by temperature dependent admittance spectroscopy, with an activation energy of 131 meV determined via that technique, in agreement with Hall effect measurements. With the concentration of this donor determined to be in the mid to high 1016 cm−3 range, elimination of this donor from the drift layer of Ga2O3 power electronics devices will be key to pushing the limits of device performance. Indeed, analytical assessment of the specific on-resistance (Ronsp) and breakdown voltage of Schottky diodes containing the 110 meV donor indicates that incomplete ionization increases Ronsp and decreases breakdown voltage as compared to Ga2O3 Schottky diodes containing only the shallow donor. The reduced performance due to incomplete ionization occurs in addition to the usual tradeoff between Ronsp and breakdown voltage.
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Affiliation(s)
- Adam T Neal
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright Patterson AFB, OH, USA. .,Universal Technology Corporation, Dayton, OH, USA.
| | - Shin Mou
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright Patterson AFB, OH, USA.
| | - Roberto Lopez
- Texas State University, Department of Physics, San Marco, TX, USA
| | - Jian V Li
- Texas State University, Department of Physics, San Marco, TX, USA
| | - Darren B Thomson
- Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, OH, USA
| | - Kelson D Chabak
- Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, OH, USA
| | - Gregg H Jessen
- Air Force Research Laboratory, Sensors Directorate, Wright Patterson AFB, OH, USA
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6
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Landy J, Walker AW, Li JV, Al-Hassi HO, Ronde E, English NR, Mann ER, Bernardo D, McLaughlin SD, Parkhill J, Ciclitira PJ, Clark SK, Knight SC, Hart AL. Variable alterations of the microbiota, without metabolic or immunological change, following faecal microbiota transplantation in patients with chronic pouchitis. Sci Rep 2015; 5:12955. [PMID: 26264409 PMCID: PMC4532993 DOI: 10.1038/srep12955] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 07/06/2015] [Indexed: 12/17/2022] Open
Abstract
Faecal microbiota transplantation (FMT) is effective in the treatment of Clostridium difficile infection, where efficacy correlates with changes in microbiota diversity and composition. The effects of FMT on recipient microbiota in inflammatory bowel diseases (IBD) remain unclear. We assessed the effects of FMT on microbiota composition and function, mucosal immune response, and clinical outcome in patients with chronic pouchitis. Eight patients with chronic pouchitis (current PDAI ≥7) were treated with FMT via nasogastric administration. Clinical activity was assessed before and four weeks following FMT. Faecal coliform antibiotic sensitivities were analysed, and changes in pouch faecal and mucosal microbiota assessed by 16S rRNA gene pyrosequencing and (1)H NMR spectroscopy. Lamina propria dendritic cell phenotype and cytokine profiles were assessed by flow cytometric analysis and multiplex assay. Following FMT, there were variable shifts in faecal and mucosal microbiota composition and, in some patients, changes in proportional abundance of species suggestive of a "healthier" pouch microbiota. However, there were no significant FMT-induced metabolic or immunological changes, or beneficial clinical response. Given the lack of clinical response following FMT via a single nasogastric administration our results suggest that FMT/bacteriotherapy for pouchitis patients requires further optimisation.
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Affiliation(s)
- J Landy
- 1] IBD Unit, Gastroenterology Dept. St Mark's Hospital, Harrow, London, UK [2] Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - A W Walker
- 1] Pathogen Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK [2] Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Greenburn Road, Aberdeen, UK
| | - J V Li
- Centre for Digestive and Gut Health &Division of Computational and Systems Medicine, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK
| | - H O Al-Hassi
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - E Ronde
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - N R English
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - E R Mann
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - D Bernardo
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - S D McLaughlin
- School of Health and Social Care, Bournemouth University, Bournemouth, UK
| | - J Parkhill
- Pathogen Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - P J Ciclitira
- Department of Gastroenterology, The Rayne Institute, St Thomas' Hospital, London, UK
| | - S K Clark
- Department of Surgery, St Mark's Hospital, Harrow, London, UK
| | - S C Knight
- Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
| | - A L Hart
- 1] IBD Unit, Gastroenterology Dept. St Mark's Hospital, Harrow, London, UK [2] Antigen Presentation Research Group, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, UK
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7
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Wu Q, Li JV, Seyfried F, le Roux CW, Ashrafian H, Athanasiou T, Fenske W, Darzi A, Nicholson JK, Holmes E, Gooderham NJ. Metabolic phenotype-microRNA data fusion analysis of the systemic consequences of Roux-en-Y gastric bypass surgery. Int J Obes (Lond) 2015; 39:1126-34. [PMID: 25783038 PMCID: PMC4766927 DOI: 10.1038/ijo.2015.33] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/22/2015] [Indexed: 01/21/2023]
Abstract
Background/Objectives: Bariatric surgery offers sustained marked weight loss and often remission of type 2 diabetes, yet the mechanisms of establishment of these health benefits are not clear. Subjects/Methods: We mapped the coordinated systemic responses of gut hormones, the circulating miRNAome and the metabolome in a rat model of Roux-en-Y gastric bypass (RYGB) surgery. Results: The response of circulating microRNAs (miRNAs) to RYGB was striking and selective. Analysis of 14 significantly altered circulating miRNAs within a pathway context was suggestive of modulation of signaling pathways including G protein signaling, neurodegeneration, inflammation, and growth and apoptosis responses. Concomitant alterations in the metabolome indicated increased glucose transport, accelerated glycolysis and inhibited gluconeogenesis in the liver. Of particular significance, we show significantly decreased circulating miRNA-122 levels and a more modest decline in hepatic levels, following surgery. In mechanistic studies, manipulation of miRNA-122 levels in a cell model induced changes in the activity of key enzymes involved in hepatic energy metabolism, glucose transport, glycolysis, tricarboxylic acid cycle, pentose phosphate shunt, fatty-acid oxidation and gluconeogenesis, consistent with the findings of the in vivo surgery-mediated responses, indicating the powerful homeostatic activity of the miRNAs. Conclusions: The close association between energy metabolism, neuronal signaling and gut microbial metabolites derived from the circulating miRNA, plasma, urine and liver metabolite and gut hormone correlations further supports an enhanced gut-brain signaling, which we suggest is hormonally mediated by both traditional gut hormones and miRNAs. This transomic approach to map the crosstalk between the circulating miRNAome and metabolome offers opportunities to understand complex systems biology within a disease and interventional treatment setting.
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Affiliation(s)
- Q Wu
- Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK
| | - J V Li
- 1] Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK [2] Center for Digestive and Gut Health, Institute of Global Health Innovation, Imperial College London, London, UK
| | - F Seyfried
- Department of General and Visceral, Vascular and Pediatric Surgery, University Hospital of Würzburg, Würzburg, Germany
| | - C W le Roux
- 1] Diabetes Complications Research Centre, Pathology, Conway Institute, School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland [2] Investigative Science, Imperial College London, London, UK
| | - H Ashrafian
- Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK
| | - T Athanasiou
- Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK
| | - W Fenske
- Department of General and Visceral, Vascular and Pediatric Surgery, University Hospital of Würzburg, Würzburg, Germany
| | - A Darzi
- Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK
| | - J K Nicholson
- 1] Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK [2] Center for Digestive and Gut Health, Institute of Global Health Innovation, Imperial College London, London, UK
| | - E Holmes
- 1] Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK [2] Center for Digestive and Gut Health, Institute of Global Health Innovation, Imperial College London, London, UK
| | - N J Gooderham
- Division of Computational and Systems Medicine, Department of Surgery and Cancer Imperial College London, South Kensington, London, UK
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8
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Steirer KX, Garris RL, Li JV, Dzara MJ, Ndione PF, Ramanathan K, Repins I, Teeter G, Perkins CL. Co-solvent enhanced zinc oxysulfide buffer layers in Kesterite copper zinc tin selenide solar cells. Phys Chem Chem Phys 2015; 17:15355-64. [DOI: 10.1039/c5cp01607j] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Performance deficiencies from the too large conduction band offset between Cu2ZnSnSe4/ZnOS heterojunctions are abated by the inclusion of a co-solvent during aqueous growth of the buffer layer.
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Affiliation(s)
- K. Xerxes Steirer
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Rebekah L. Garris
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Jian V. Li
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Michael J. Dzara
- Rochester Institute of Technology
- Chemical Engineering Department
- Rochester
- USA
| | - Paul F. Ndione
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Kannan Ramanathan
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Ingrid Repins
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Glenn Teeter
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
| | - Craig L. Perkins
- National Renewable Energy Laboratory
- Chemical and Materials Science
- Golden
- USA
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9
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Lee YS, Chua D, Brandt RE, Siah SC, Li JV, Mailoa JP, Lee SW, Gordon RG, Buonassisi T. Atomic layer deposited gallium oxide buffer layer enables 1.2 V open-circuit voltage in cuprous oxide solar cells. Adv Mater 2014; 26:4704-4710. [PMID: 24862543 DOI: 10.1002/adma.201401054] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/10/2014] [Indexed: 06/03/2023]
Abstract
The power conversion efficiency of solar cells based on copper (I) oxide (Cu2 O) is enhanced by atomic layer deposition of a thin gallium oxide (Ga2 O3 ) layer. By improving band-alignment and passivating interface defects, the device exhibits an open-circuit voltage of 1.20 V and an efficiency of 3.97%, showing potential of over 7% efficiency.
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Affiliation(s)
- Yun Seog Lee
- Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
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10
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Ma J, Kuciauskas D, Albin D, Bhattacharya R, Reese M, Barnes T, Li JV, Gessert T, Wei SH. Dependence of the minority-carrier lifetime on the stoichiometry of CdTe using time-resolved photoluminescence and first-principles calculations. Phys Rev Lett 2013; 111:067402. [PMID: 23971610 DOI: 10.1103/physrevlett.111.067402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Indexed: 05/25/2023]
Abstract
CdTe is one of the most promising materials for thin-film solar cells. However, further improvement of its performance is hindered by its relatively short minority-carrier lifetime. Combining theoretical calculations and experimental measurements, we find that for both intrinsic CdTe and CdTe solar cell devices, longer minority-carrier lifetimes can be achieved under Cd-rich conditions, in contrast to the previous belief that Te-rich conditions are more beneficial. First-principles calculations suggest that the dominant recombination centers limiting the minority-carrier lifetime are the Te antisite and Te interstitial. Therefore, we propose that to optimize the solar cell performance, extrinsic p-type doping (e.g., N, P, or As substitution on Te sites) in CdTe under Cd-rich conditions should be a good approach to simultaneously increase both the minority-carrier lifetime and hole concentration.
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Affiliation(s)
- Jie Ma
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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Ashrafian H, Athanasiou T, Li JV, Bueter M, Ahmed K, Nagpal K, Holmes E, Darzi A, Bloom SR. Diabetes resolution and hyperinsulinaemia after metabolic Roux-en-Y gastric bypass. Obes Rev 2011; 12:e257-72. [PMID: 20880129 DOI: 10.1111/j.1467-789x.2010.00802.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The global prevalence of type 2 diabetes mellitus and impaired glucose metabolism continues to rise in conjunction with the pandemic of obesity. The metabolic Roux-en-Y gastric bypass operation offers the successful resolution of diabetes in addition to sustained weight loss and excellent long-term outcomes in morbidly obese individuals. The procedure consists of the physiological BRAVE effects: (i) Bile flow alteration; (ii) Reduction of gastric size; (iii) Anatomical gut rearrangement and altered flow of nutrients; (iv) Vagal manipulation and (v) Enteric gut hormone modulation. This operation provides anti-diabetic effects through decreasing insulin resistance and increasing the efficiency of insulin secretion. These metabolic outcomes are achieved through weight-independent and weight-dependent mechanisms. These include the foregut, midgut and hindgut mechanisms, decreased inflammation, fat, adipokine and bile metabolism, metabolic modulation, shifts in gut microbial composition and intestinal gluconeogenesis. In a small minority of patients, gastric bypass results in hyperinsulinaemic hypoglycaemia that may lead to nesidioblastosis (pancreatic beta-cell hypertrophy with islet hyperplasia). Elucidating the precise metabolic mechanisms of diabetes resolution and hyperinsulinaemia after surgery can lead to improved operations and disease-specific procedures including 'diabetes surgery'. It can also improve our understanding of diabetes pathogenesis that may provide novel strategies for the management of metabolic syndrome and impaired glucose metabolism.
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Affiliation(s)
- H Ashrafian
- The Department of Surgery and Cancer, Imperial College London, London, UK.
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Ashrafian H, Athanasiou T, Li JV, Bueter M, Ahmed K, Nagpal K, Holmes E, Darzi A, Bloom SR. Diabetes resolution and hyperinsulinaemia after metabolic Roux-en-Y gastric bypass. Obes Rev 2010. [PMID: 20880129 DOI: 10.1111/j.1467–789x.2010.00802.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The global prevalence of type 2 diabetes mellitus and impaired glucose metabolism continues to rise in conjunction with the pandemic of obesity. The metabolic Roux-en-Y gastric bypass operation offers the successful resolution of diabetes in addition to sustained weight loss and excellent long-term outcomes in morbidly obese individuals. The procedure consists of the physiological BRAVE effects: (i) Bile flow alteration; (ii) Reduction of gastric size; (iii) Anatomical gut rearrangement and altered flow of nutrients; (iv) Vagal manipulation and (v) Enteric gut hormone modulation. This operation provides anti-diabetic effects through decreasing insulin resistance and increasing the efficiency of insulin secretion. These metabolic outcomes are achieved through weight-independent and weight-dependent mechanisms. These include the foregut, midgut and hindgut mechanisms, decreased inflammation, fat, adipokine and bile metabolism, metabolic modulation, shifts in gut microbial composition and intestinal gluconeogenesis. In a small minority of patients, gastric bypass results in hyperinsulinaemic hypoglycaemia that may lead to nesidioblastosis (pancreatic beta-cell hypertrophy with islet hyperplasia). Elucidating the precise metabolic mechanisms of diabetes resolution and hyperinsulinaemia after surgery can lead to improved operations and disease-specific procedures including 'diabetes surgery'. It can also improve our understanding of diabetes pathogenesis that may provide novel strategies for the management of metabolic syndrome and impaired glucose metabolism.
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Affiliation(s)
- H Ashrafian
- The Department of Surgery and Cancer, Imperial College London, London, UK.
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Garcia-Perez I, Couto Alves A, Angulo S, Li JV, Utzinger J, Ebbels TMD, Legido-Quigley C, Nicholson JK, Holmes E, Barbas C. Bidirectional correlation of NMR and capillary electrophoresis fingerprints: a new approach to investigating Schistosoma mansoni infection in a mouse model. Anal Chem 2010; 82:203-10. [PMID: 19961175 DOI: 10.1021/ac901728w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We demonstrate the statistical integration of nuclear magnetic resonance (NMR) spectroscopy and capillary electrophoresis (CE) data in order to describe a pathological state caused by Schistosoma mansoni infection in a mouse model based on urinary metabolite profiles. Urine samples from mice 53 days post infection with S. mansoni and matched controls were analyzed via NMR spectroscopy and CE. The two sets of metabolic profiles were first processed and analyzed independently and were subsequently integrated using statistical correlation methods in order to facilitate cross assignment of metabolites. Using this approach, metabolites such as 3-ureidopropionate, p-cresol glucuronide, phenylacetylglycine, indoxyl sulfate, isocitrate, and trimethylamine were identified as differentiating between infected and control animals. These correlation analyses facilitated structural elucidation using the identification power of one technique to enhance and validate the other, but also highlighted the enhanced ability to detect functional correlations between metabolites, thereby providing potential for achieving deeper mechanistic insight into the biological process.
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Affiliation(s)
- I Garcia-Perez
- Faculty of Pharmacy, San Pablo-CEU, Campus Monteprincipe, Boadilla del Monte, 28668 Madrid, Spain
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Li JV, Johnston SW, Yan Y, Levi DH. Measuring temperature-dependent activation energy in thermally activated processes: a 2D Arrhenius plot method. Rev Sci Instrum 2010; 81:033910. [PMID: 20370195 DOI: 10.1063/1.3361130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Thermally activated processes are characterized by two key quantities, activation energy (E(a)) and pre-exponential factor (nu(0)), which may be temperature dependent. The accurate measurement of E(a), nu(0), and their temperature dependence is critical for understanding the thermal activation mechanisms of non-Arrhenius processes. However, the classic 1D Arrhenius plot-based methods cannot unambiguously measure E(a), nu(0), and their temperature dependence due to the mathematical impossibility of resolving two unknown 1D arrays from one 1D experimental data array. Here, we propose a 2D Arrhenius plot method to solve this fundamental problem. Our approach measures E(a) at any temperature from matching the first and second moments of the data calculated with respect to temperature and rate in the 2D temperature-rate plane, and therefore is able to unambiguously solve E(a), nu(0), and their temperature dependence. The case study of deep level emission in a Cu(In,Ga)Se(2) solar cell using the 2D Arrhenius plot method reveals clear temperature dependent behavior of E(a) and nu(0), which has not been observable by its 1D predecessors.
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Affiliation(s)
- Jian V Li
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA.
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