| 1. |
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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 3. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 4. |
- Campbell, PJ, et al.
(författare)
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Pan-cancer analysis of whole genomes
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
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Tidskriftsartikel (refereegranskat)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
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| 5. |
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| 6. |
- Jin, Ying-Hui, et al.
(författare)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
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Ingår i: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 7. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 8. |
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| 9. |
- Schuettpelz, Eric, et al.
(författare)
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A community-derived classification for extant lycophytes and ferns
- 2016
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Ingår i: Journal of Systematics and Evolution. - : Wiley. - 1674-4918 .- 1759-6831. ; 54:6, s. 563-603
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Tidskriftsartikel (refereegranskat)abstract
- Phylogeny has long informed pteridophyte classification. As our ability to infer evolutionary trees has improved, classifications aimed at recognizing natural groups have become increasingly predictive and stable. Here, we provide a modern, comprehensive classification for lycophytes and ferns, down to the genus level, utilizing a community-based approach. We use monophyly as the primary criterion for the recognition of taxa, but also aim to preserve existing taxa and circumscriptions that are both widely accepted and consistent with our understanding of pteridophyte phylogeny. In total, this classification treats an estimated 11 916 species in 337 genera, 51 families, 14 orders, and two classes. This classification is not intended as the final word on lycophyte and fern taxonomy, but rather a summary statement of current hypotheses, derived from the best available data and shaped by those most familiar with the plants in question. We hope that it will serve as a resource for those wanting references to the recent literature on pteridophyte phylogeny and classification, a framework for guiding future investigations, and a stimulus to further discourse.
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| 10. |
- Aalto, Daniel, et al.
(författare)
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John-Nirenberg lemmas for a doubling measure
- 2011
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Ingår i: Studia Mathematica. - : Institute of Mathematics, Polish Academy of Sciences. - 0039-3223 .- 1730-6337. ; 204:1, s. 21-37
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Tidskriftsartikel (refereegranskat)abstract
- We study, in the context of doubling metric measure spaces, a class of BMO type functions defined by John and Nirenberg. In particular, we present a new version of the Calderon-Zygmund decomposition in metric spaces and use it to prove the corresponding John Nirenberg inequality.
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| 11. |
- Abolfathi, Bela, et al.
(författare)
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The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment
- 2018
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Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2
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Tidskriftsartikel (refereegranskat)abstract
- The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
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| 12. |
- Chen, Zhi, et al.
(författare)
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Large-Area Crystalline Zeolitic Imidazolate Framework Thin Films
- 2021
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:25, s. 14124-14130
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Tidskriftsartikel (refereegranskat)abstract
- We report that continuous MOF films with highly controlled thickness (from 44 to 5100 nm) can be deposited over length scales greater than 80 centimeters by a facile, fast, and cost-effective spray-coating method. Such success relies on our discovery of unprecedented perfectly dispersed colloidal solutions consisting of amorphous MOF nanoparticles, which we adopted as precursors that readily converted to the crystalline films upon low-temperature in situ heating. The colloidal solutions allow for the fabrication of compact and uniform MOF films on a great deal of substrates such as fluorine-doped tin oxide, glass, SiO2, Al2O3, Si, Cu, and even flexible polycarbonate, widening their technological applications where substrates are essential. Despite the present work focuses on the fabrication of uniform cobalt-(2-methylimidazole)2 and zinc-(2-methylimidazole)2 films, our findings mark a great possibility in producing other high-quality MOF thin films on a large scale.
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| 13. |
- Fan, Ke, et al.
(författare)
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Direct Observation of Structural Evolution of Metal Chalcogenide in Electrocatalytic Water Oxidation
- 2018
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:12, s. 12369-12379
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Tidskriftsartikel (refereegranskat)abstract
- As one of the most remarkable oxygen evolution reaction (OER) electrocatalysts, metal chalcogenides have been intensively reported during the past few decades because of their high OER activities. It has been reported that electron-chemical conversion of metal OER chalcogenides into oxides/hydroxides would take place after the OER. However, the transition mechanism of such unstable structures, as well as the real active sites and catalytic activity during the OER for these electrocatalysts, has not been understood yet; therefore a direct observation for the electrocatalytic water oxidation process, especially at nano or even angstrom scale, is urgently needed. In this research, by employing advanced Cs-corrected transmission electron microscopy (TEM), a step by step oxidational evolution of amorphous electrocatalyst CoSx into crystallized CoOOH in the OER has been in situ captured: irreversible conversion of CoSx to crystallized CoOOH is initiated on the surface of the electrocatalysts with a morphology change via Co(OH)(2) intermediate during the OER measurement, where CoOOH is confirmed as the real active species. Besides, this transition process has also been confirmed by multiple applications of X-ray photoelectron spectroscopy (XPS), in situ Fourier-transform infrared spectroscopy (FTIR), and other ex situ technologies. Moreover, on the basis of this discovery, a high-efficiency electrocatalyst of a nitrogen-doped graphene foam (NGF) coated by CoSx has been explored through a thorough structure transformation of CoOOH. We believe this in situ and in-depth observation of structural evolution in the OER measurement can provide insights into the fundamental understanding of the mechanism for the OER catalysts, thus enabling the more rational design of low-cost and high-efficient electrocatalysts for water splitting.
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| 14. |
- Fang, Ruisen, et al.
(författare)
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Late Ediacaran cavity-dwelling filamentous microorganisms accommodated in a valve-like organism from the uppermost Dengying Formation in eastern Yunnan of South China
- 2022
-
Ingår i: Precambrian Research. - : Elsevier. - 0301-9268 .- 1872-7433. ; 379
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Tidskriftsartikel (refereegranskat)abstract
- The Ediacaran–Cambrian transition, one of the major turning points in Earth’s history, is characterized by an epoch-making change in biosphere. In South China, the late Ediacaran Dengying Formation (ca. 551–538 Ma) is an important stratigraphic unit yielding trace fossils, tubular skeletal fossils and some complex forms that represent possible bilateral animals. The fossil-bearing Ediacaran strata of eastern Yunnan is hitherto known from the Jiucheng Member containing the Jiangchuan Biota, together with the enigmatic cosmopolitan taxon Shaanxilithes. Here, we present for the first time cavity-dwelling filamentous microorganisms accommodated within a valve-like fossil from the upper Baiyanshao Member of the Dengying Formation at the Sujiawa Section in Huize County, eastern Yunnan of China. SEM scanning and Micro-CT reconstruction indicate that the well-preserved filaments were characterized by mycelial network structures with abundant branching pattern. Preservation of filamentous microorganisms might result from the decay process of soft parts that were originally accommodated and enclosed within the valve-like organism, and subsequently preserved by early diagenetic phosphatization, which obscures their original organic identity and chemical composition. This paper potentially presents the first fossil evidence of a saprophytic relationship between microorganisms as decomposers and a valve-like organism prior to the eve of the Cambrian Explosion of metazoan animals.
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| 15. |
- Gao, Yaqing, et al.
(författare)
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Housing environment and early childhood development in sub-Saharan Africa: A cross-sectional analysis.
- 2021
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Ingår i: PLoS medicine. - : Public Library of Science (PLoS). - 1549-1676 .- 1549-1277. ; 18:4
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Forskningsöversikt (refereegranskat)abstract
- The influence of the safety and security of environments on early childhood development (ECD) has been under-explored. Although housing might be linked to ECD by affecting a child's health and a parent's ability to provide adequate care, only a few studies have examined this factor. We hypothesized that housing environment is associated with ECD in sub-Saharan Africa (SSA).From 92,433 children aged 36 to 59 months who participated in Multiple Indicator Cluster Survey (MICS) in 20 SSA countries, 88,271 were tested for cognitive and social-emotional development using the Early Childhood Development Index (ECDI) questionnaire and were thus included in this cross-sectional analysis. Children's mean age was 47.2 months, and 49.8% were girls. Children were considered developmentally on track in a certain domain if they failed no more than 1 ECDI item in that domain. In each country, we used conditional logistic regression models to estimate the association between improved housing (housing with finished building materials, improved drinking water, improved sanitation facilities, and sufficient living area) and children's cognitive and social-emotional development, accounting for contextual effects and socioeconomic factors. Estimates from each country were pooled using random-effects meta-analyses. Subgroup analyses were conducted by the child's gender, maternal education, and household wealth quintiles. On-track cognitive development was associated with improved housing (odds ratio [OR] = 1.15, 95% CI 1.06 to 1.24, p < 0.001), improved drinking water (OR = 1.07, 95% CI 1.00 to 1.14, p = 0.046), improved sanitation facilities (OR = 1.15, 95% CI 1.03 to 1.28, p = 0.014), and sufficient living area (OR = 1.06, 95% CI 1.01 to 1.10, p = 0.018). On-track social-emotional development was associated with improved housing only in girls (OR = 1.14, 95% CI 1.04 to 1.25, p = 0.006). The main limitations of this study included the cross-sectional nature of the datasets and the use of the ECDI, which lacks sensitivity to measure ECD outcomes.In this study, we observed that improved housing was associated with on-track cognitive development and with on-track social-emotional development in girls. These findings suggest that housing improvement in SSA may be associated not only with benefits for children's physical health but also with broader aspects of healthy child development.
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| 16. |
- Gao, Yaqing, et al.
(författare)
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Inequality in measles vaccination coverage in the "big six" countries of the WHO South-East Asia region.
- 2020
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Ingår i: Human vaccines & immunotherapeutics. - : Informa UK Limited. - 2164-554X .- 2164-5515. ; 16:7, s. 1485-1497
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Tidskriftsartikel (refereegranskat)abstract
- The "big six" countries (Bangladesh, India, Indonesia, Myanmar, Nepal, and Thailand) in the World Health Organization South-East Asia Region (WHO SEAR) are currently facing severe challenges in measles elimination and consequent childhood mortality reduction, with inadequacies and inequalities in the coverage of the measles-containing-vaccine first-dose (MCV1) being major obstacles. However, these issues of inequality in MCV1 coverage have not yet been systematically examined. We used data from the latest Demographic and Health Surveys and Multiple Indicator Cluster Surveys. To provide a comprehensive picture of existing MCV1 coverage gaps, data were disaggregated by geographic location, as well as by socioeconomic and nutritional dimensions. National MCV1 coverage ranged from 77% in Myanmar to 92% in Thailand. Only nine of the 104 sub-national districts had achieved the 95% MCV1 coverage goal as set by the WHO. Geographic inequalities were more pronounced in countries with lower coverage levels. Areas in clusters with poor MCV1 coverage performances as well as disadvantaged socioeconomic profiles require increased attention. Inequalities were evident in all countries, except Thailand, and were more pronounced in the sectors of wealth, education, antenatal care (ANC) status, and vitamin A supplementation (VAS) when compared against the areas of gender and urban/rural residence. Wealth-related inequality in Bangladesh, education-related inequality in Indonesia, ANC-related inequalities in Myanmar and Nepal, and VAS-related inequalities in Indonesia and Myanmar were all noteworthy. Equity-oriented changes in policies focusing on health promotion and integrated interventions among disadvantaged populations need to be implemented in order to increase MCV1 coverage and reduce childhood mortality.
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| 17. |
- Ge, Yue, et al.
(författare)
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Environmental OMICS: Current Status and Future Directions
- 2013
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Ingår i: JOURNAL OF INTEGRATED OMICS. - : Proteomass Scientific Society. - 2182-0287. ; 3:2, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Applications of OMICS to high throughput studies of changes of genes, RNAs, proteins, metabolites, and their associated functionsin cells or organisms exposed to environmental chemicals has led to the emergence of a very active research field: environmental OMICS.This developing field holds an important key for improving the scientific basis for understanding the potential impacts of environmentalchemicals on both health and the environment. Here we describe the state of environmental OMICS with an emphasis on its recent accomplishmentsand its problems and potential solutions to facilitate the incorporation of OMICS into mainstream environmental and healthresearch.Data sources: We reviewed relevant and recently published studies on the applicability and usefulness of OMICS technologies to the identificationof toxicity pathways, mechanisms, and biomarkers of environmental chemicals for environmental and health risk monitoring andassessment, including recent presentations and discussions on these issues at The First International Conference on Environmental OMICS(ICEO), held in Guangzhou, China during November 8-12, 2011. This paper summarizes our review.Synthesis: Environmental OMICS aims to take advantage of powerful genomics, transcriptomics, proteomics, and metabolomics tools toidentify novel toxicity pathways/signatures/biomarkers so as to better understand toxicity mechanisms/modes of action, to identify/categorize/prioritize/screen environmental chemicals, and to monitor and predict the risks associated with exposure to environmental chemicalson human health and the environment. To improve the field, some lessons learned from previous studies need to be summarized, aresearch agenda and guidelines for future studies need to be established, and a focus for the field needs to be developed.Conclusions: OMICS technologies for identification of RNA, protein, and metabolic profiles and endpoints have already significantly improvedour understanding of how environmental chemicals affect our ecosystem and human health. OMICS breakthroughs are empoweringthe fields of environmental toxicology, chemical toxicity characterization, and health risk assessment. However, environmental OMICS is stillin the data generation and collection stage. Important data gaps in linking and/or integrating toxicity data with OMICS endpoints/profilesneed to be filled to enable understanding of the potential impacts of chemicals on human health and the environment. It is expected thatfuture environmental OMICS will focus more on real environmental issues and challenges such as the characterization of chemical mixturetoxicity, the identification of environmental and health biomarkers, and the development of innovative environmental OMICS approachesand assays. These innovative approaches and assays will inform chemical toxicity testing and prediction, ecological and health risk monitoringand assessment, and natural resource utilization in ways that maintain human health and protects the environment in a sustainable manner.
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| 18. |
- Guo, Peng Fei, et al.
(författare)
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Iron-chelated thermoresponsive polymer brushes on bismuth titanate nanosheets for metal affinity separation of phosphoproteins
- 2020
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Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765. ; 196
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Tidskriftsartikel (refereegranskat)abstract
- Separation of phosphoproteins plays an important role for identification of biomarkers in life science. In this work, bismuth titanate supported, iron-chelated thermoresponsive polymer brushes were prepared for selective separation of phosphoproteins. The iron-chelated thermoresponsive polymer brushes were synthesized by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and glycidyl methacrylate, followed by a ring opening reaction of epoxy group, and chelation of the obtained cis-diols with Fe3+ ions. The composite material was characterized to determine the size and thickness, the content of the organic polymer and the metal loading. The bismuth titanate supported, iron-chelated thermoresponsive polymer brushes showed selective binding for phosphoproteins in the presence of abundant interfering proteins, and a high binding capacity for phosphoproteins by virtue of the metal affinity between the metal ions on the polymer brushes and the phosphate groups in the phosphoproteins (664 mg β-Casein per g sorbent). The thermoresponsive property of the polymer brushes made it possible to adjust phosphoprotein binding by changing temperature. Finally, separation of phosphoproteins from a complex biological sample (i.e. milk) was demonstrated using the nanosheet-supported thermoresponsive polymer brushes.
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| 19. |
- Han, Xin-Bao, et al.
(författare)
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Ultrasmall Abundant Metal-Based Clusters as Oxygen-Evolving Catalysts
- 2019
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 141:1, s. 232-239
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen evolution reaction is a crucial step in water electrolysis to develop clean and renewable energy. Although noble metal-based catalysts have demonstrated high activity for the oxygen evolution reaction, their application is limited by their high cost and low availability. Here we report the use of a molecule-to-cluster strategy for preparing ultrasmall trimetallic clusters by using the polyoxometalate molecule as a precursor. Ultrafine (0.8 nm) transition-metal clusters with controllable chemical composition are obtained. The transition-metal clusters enable highly efficient oxygen evolution through water electrolysis in alkaline media, manifested by an overpotential of 192 mV at 10 mA cm–2, a low Tafel slope of 36 mV dec–1, and long-term stability for 30 h of electrolysis. We note, however, that besides the excellent performance as an oxygen evolution catalyst, our molecule-to-cluster strategy provides a means to achieve well-defined transition-metal clusters in the subnanometer regime, which potentially can have an impact on several other applications.
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| 20. |
- He, Li, et al.
(författare)
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Evolutionary origin and establishment of a dioecious diploid-tetraploid complex
- 2023
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Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 32:11, s. 2732-2749
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Tidskriftsartikel (refereegranskat)abstract
- Polyploids recurrently emerge in angiosperms, but most polyploids are likely to go extinct before establishment due to minority cytotype exclusion, which may be specifically a constraint for dioecious plants. Here we test the hypothesis that a stable sex-determination system and spatial/ecological isolation facilitate the establishment of dioecious polyploids. We determined the ploidy levels of 351 individuals from 28 populations of the dioecious species Salix polyclona, and resequenced 190 individuals of S. polyclona and related taxa for genomic diversity analyses. The ploidy survey revealed a frequency 52% of tetraploids in S. polyclona, and genomic k-mer spectra analyses suggested an autopolyploid origin for them. Comparisons of diploid male and female genomes identified a female heterogametic sex-determining factor on chromosome 15, which probably also acts in the dioecious tetraploids. Phylogenetic analyses revealed two diploid clades and a separate clade/grade of tetraploids with a distinct geographic distribution confined to western and central China, where complex mountain systems create higher levels of environmental heterogeneity. Fossil-calibrated phylogenies showed that the polyploids emerged during 7.6–2.3 million years ago, and population demographic histories largely matched the geological and climatic history of the region. Our results suggest that inheritance of the sex-determining system from the diploid progenitor as intrinsic factor and spatial isolation as extrinsic factor may have facilitated the preservation and establishment of polyploid dioecious populations.
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| 21. |
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| 22. |
- Hong, Yue, et al.
(författare)
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Damping Effect Coupled with the Internal Translator Mass of Linear Generator-Based Wave Energy Converters
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 13:17
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Tidskriftsartikel (refereegranskat)abstract
- The damping effect, induced inside the linear generator, is a vital factor to improve the conversion efficiency of wave energy converters (WEC). As part of the mechanical design, the translator mass affects the damping force and eventually affects the performance of the WEC by converting wave energy into electricity. This paper proposes research on the damping effect coupled with translator mass regarding the generated power from WEC. Complicated influences from ocean wave climates along the west coast of Sweden are also included. This paper first compares three cases of translator mass with varied damping effects. A further investigation on coupling effects is performed using annual energy absorption under a series of sea states. Results suggest that a heavier translator may promote the damping effect and therefore improve the power production. However, the hinder effect is also observed and analyzed in specific cases. In this paper, the variations in the optimal damping coefficient are observed and discussed along with different cases.
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| 23. |
- Hong, Yue, et al.
(författare)
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Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates
- 2021
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC's annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC's energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC's maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC's annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.
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| 24. |
- Hong, Yue, et al.
(författare)
-
Impact of Generator Stroke Length on Energy Production for a Direct Drive Wave Energy Converter
- 2016
-
Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 9:9
-
Tidskriftsartikel (refereegranskat)abstract
- The Lysekil wave energy converter (WEC), developed by the wave energy research group of Uppsala University, has evolved through a variety of mechanical designs since the first prototype was installed in 2006. The hundreds of engineering decisions made throughout the design processes have been based on a combination of theory, know-how from previous experiments, and educated guesses. One key parameter in the design of the WECs linear generator is the stroke length. A long stroke requires a taller WEC with associated economical and mechanical challenges, but a short stroke limits the power production. The 2-m stroke of the current WECs has been an educated guess for the Swedish wave climate, though the consequences of this choice on energy absorption have not been studied. When the WEC technology is considered for international waters, with larger waves and challenges of energy absorption and survivability, the subject of stroke length becomes even more relevant. This paper studies the impact of generator stroke length on energy absorption for three sites off the coasts of Sweden, Chile and Scotland. 2-m, 4-m, and unlimited stroke are considered. Power matrices for the studied WEC prototype are presented for each of the studied stroke lengths. Presented results quantify the losses incurred by a limited stroke. The results indicate that a 2-m stroke length is likely to be a good choice for Sweden, but 4-m is likely to be necessary in more energetic international waters.
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| 25. |
- Hong, Yue, et al.
(författare)
-
Linear generator-based wave energy converter model with experimental verification and three loading strategies
- 2016
-
Ingår i: IET Renewable Power Generation. - : Institution of Engineering and Technology (IET). - 1752-1416 .- 1752-1424. ; 10:3, s. 349-359
-
Tidskriftsartikel (refereegranskat)abstract
- Within the Lysekil wave energy research project at the Swedish west coast, more than ten Wave Energy Converters (WECs) prototypes have been developed and installed in an ocean based test site. Since 2006 various experiments have been conducted and the generated electricity was delivered to shore at a nearby island. While experiments are essential for the development of wave energy converters, theoretical studies and simulations are an important complement – not only in the search for advanced designs with higher efficiency, but also for improving the economic viability of the studied concepts. In this paper a WEC model is presented. The model consists of three subsystems: i) the hydrodynamic source, ii) the linear generator model, and iii) the electrical conversion system. After the validation with the experimental results at the research site, the generator model is connected to three passive load strategies – linear resistive load, passive rectification and resonance circuit. The paper focuses on analysing the operation of the model coupled with three load cases. The results prove that the WEC model correctly simulates the linear generator developed in the Lysekil Project. Moreover, the comparison among different load cases is made and discussed. The results gives an indication of the efficiency of energy production as well as the force ripples and resulting mechanical loads on the wave energy converters.
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| 26. |
- Hong, Yue, 1986-
(författare)
-
Numerical Modelling and Mechanical Studies on a Point Absorber Type Wave Energy Converter
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oceans cover two thirds of the Earth’s surface and the energy potential of ocean waves as a renewable energy source is huge. It would therefore be a tremendous achievement if the vast mechanical energy in waves was converted into a form of energy that could be used successfully by society. For years, scientists and engineers have endeavored to exploit this renewable energy by inventing various generators designed to transform wave energy into electrical energy. Generally, this sort of generator is called a Wave Energy Converter (WEC).In this thesis, the research is based on the WEC developed in the Lysekil Project. The Lysekil Project is led by a research group at Uppsala University and has a test site located on the west coast of Sweden. The project started in 2002. So far, more than ten prototypes of the WEC have been deployed and relevant experiments have been carried out at the test site. The WEC developed at Uppsala University can be categorized as a point absorber. It consists of a direct-drive linear generator connected to a floating buoy. The linear generator is deployed on the seabed and driven by a floating buoy to extract wave energy. The absorbed energy is converted to electricity and transmitted to a measuring station on land.The work presented in this thesis focuses on building a linear generator model which is able to predict the performance of the Lysekil WEC. Studies are also carried out on the damping behavior of the WEC under the impact of different sea climates. The purpose is to optimize the energy absorption with a specific optimal damping coefficient. The obtained results indicate an optimal damping for the Lysekil WEC which can be used for optimizing the damping control.Additionally, the impact two central engineering design features (the translator weight and the stroke length) are investigated. The aim is to find a reasonable structural design for the generator which balances the cost and the energy production.
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| 27. |
- Hong, Yue, et al.
(författare)
-
Review on electrical control strategies for wave energy converting systems
- 2014
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 31, s. 329-342
-
Forskningsöversikt (refereegranskat)abstract
- Renewable energy techniques are now gaining more and more attention as the years pass by, not only because of the threat of climate change but also, e.g. due to serious pollution problems in some countries and because the renewable energy technologies have matured and can be depended upon an increasing degree. The energy from ocean waves bares tremendous potential as a source of renewable energy, and the related technologies have continually been improved during the last decades. In this paper, different types of wave energy converters are classified by their mechanical structure and how they absorb energy from ocean waves. The paper presents a review of strategies for electrical control of wave energy converters as well as energy storage techniques. Strategies of electrical control are used to achieve a higher energy absorption, and they are also of interest because of the large variety among different strategies. Furthermore, the control strategies strongly affect the complexity of both the mechanical and the electrical system, thus not only impacting energy absorption but also robustness, survivability, maintenance requirements and thus in the end the cost of electricity from ocean waves.
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| 28. |
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| 29. |
- Huang, Yue, et al.
(författare)
-
Association Between Violent Discipline at Home and Risk of Illness and Injury in Children: Findings From a Cross-sectional Study in Rural Western China.
- 2022
-
Ingår i: Journal of interpersonal violence. - : SAGE Publications. - 1552-6518 .- 0886-2605. ; 37:13-14, s. NP11413-NP11435
-
Tidskriftsartikel (refereegranskat)abstract
- To estimate the prevalence of violent discipline at home against young children, and to explore the potential association between violent discipline at home and multifaceted health risks in children. A community-based cross-sectional survey was conducted in twenty rural counties of weight provinces in western China. The information about child neglect and socio-demographic factors, exposure to different forms of violent discipline at home and four health outcomes was collected by face-to-face interview. Before analysis, the included interviews were weighted by the double-weighted comprehensive weighting. The proportion of children reported by primary caregivers to have experienced different forms of violent discipline by gender were calculated. To adjust the clustering effect of the survey design, two-level univariate and multivariate logistic regression models were constructed to evaluate the potential association between a child's exposure to violent discipline at home and risk of suffering from diarrhea, fever, cough and injury. A total of 3,682 weighted interviews were finally included in the analysis. The prevalence of any violent discipline, psychological aggression, any physical punishment and severe physical punishment were 76.4%, 57.5%, 68.3% and 14.1%, respectively. In multivariate analysis, after adjusting for clustering, there was still a positive association between a child's exposure to psychological aggression and risk of diarrhea (adjusted OR: 1.47, 95%CI: 1.14-1.90) and injury (adjusted OR: 1.95, 95%CI: 1.36-2.80); a child's exposure to any physical punishment and risk of diarrhea (adjusted OR: 1.36, 95%CI: 1.04-1.77), cough (adjusted OR: 1.37, 95%CI: 1.14-1.66), and injury (adjusted OR: 2.05, 95%CI: 1.37-3.06); and a child's exposure to severe physical punishment and risk of injury (adjusted OR: 2.07, 95%CI: 1.41-3.05). Considering that using violent discipline at home is prevalent in rural western China, and it could threaten young children's health, effective measures to prevent young children from violent discipline are urgently needed.
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| 30. |
- Huang, Yue, et al.
(författare)
-
Memory Effect of Metal-Oxide-Silicon Capacitors with Self-Assembly Double-Layer Au Nanocrystals Embedded in Atomic-Layer-Deposited HfO2 Dielectric
- 2009
-
Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 26:10
-
Tidskriftsartikel (refereegranskat)abstract
- We report the chemical self-assembly growth of Au nanocrystals on atomic-layer-deposited HfO2 films aminosilanized by (3-Aminopropyl)-trimethoxysilane aforehand for memory applications. The resulting Au nanocrystals show a density of about 4 x 10(11) cm(-2) and a diameter range of 5-8 nm. The metal-oxide-silicon capacitor with double-layer Au nanocrystals embedded in HfO2 dielectric exhibits a large C - V hysteresis window of 11.9 V for +/- 11 V gate voltage sweeps at 1 MHz, a flat-band voltage shift of 1.5 V after the electrical stress under 7 V for 1 ms, a leakage current density of 2.9 x 10(-8) A/cm(-2) at 9 V and room temperature. Compared to single-layer Au nanocrystals, the double-layer Au nanocrystals increase the hysteresis window significantly, and the underlying mechanism is thus discussed.
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| 31. |
- Jiang, Zhiping, et al.
(författare)
-
Fine tuning the hydrophobicity of counter-anions to tailor pore size in porous all-poly(ionic liquid) membranes
- 2019
-
Ingår i: Polymer international. - : Wiley. - 0959-8103 .- 1097-0126. ; 68:9, s. 1566-1569
-
Tidskriftsartikel (refereegranskat)abstract
- Charged porous polymer membranes (CPMs) emerging as a multifunctional platform for diverse applications in chemistry, materials science and biomedicine have been attracting widespread attention. Fabrication of CPMs in a controllable manner is of particular significance for optimizing their function and maximizing practical values. Herein, we report the fabrication of CPMs exclusively from poly(ionic liquid)s (PILs), and their pore size and wettability were precisely tailored by rational choice of counter-anions. Specifically, a stepwise subtle increase in hydrophobicity of the counter-anions by extending the length of fluorinated alkyl substituents, i.e. from bis(trifluoromethane sulfonyl)imide to bis(pentafluoroethane sulfonyl)imide and bis(heptafluoropropane sulfonyl)imide, decreased the average pore size gradually from 1546 to 157 and 77 nm, respectively. Meanwhile, the corresponding water contact angles increased from 90 degrees to 102 degrees and 120 degrees. The sensitive control over the porous architectures and surface wettability of CPMs by systematic variation of anion hydrophobicity provides solid proof of the impact of PIL anions on CPM structure.
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| 32. |
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| 33. |
- Li, Wenlong, et al.
(författare)
-
Enantiospecific photoresponse of sterically hindered diarylethenes for chiroptical switches and photomemories
- 2015
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Light-driven transcription, replication and enzyme catalysis are critically dependent upon a delicate transfer between molecular and supramolecular chirality. Chemists have well realized the impressive stereospecificity over many thermally accessible cycloaddition with chiral catalysts, but making light work in the enantiomer control of diarylethene photocyclization has proved to be more challenging. Here, we report a unique sterically hindered diarylethene (BBTE) system with absolute enantiospecific photocyclization and cycloreversion. Moreover, we have fully separated all the five thermally stable isomers, consisting of one achiral parallel conformer, one pair of anti-parallel ring-open enantiomers, and another pair of ring-closed enantiomers, whose absolute chiral configurations are entirely elucidated by single X-ray crystallographic analyses. The photo-responsive feature exhibits a reversible, complete enantio-control transformation without racemism, offering an unrivaled unimolecular enantiospecific platform for potential applications as bistable chiroptical switches and all-photonic photomemories with optical rotation as non-destructive readout.
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| 34. |
- Liao, Zhong-Wei, et al.
(författare)
-
Robust Low Voltage Program-Erasable Cobalt-Nanocrystal Memory Capacitors with Multistacked Al2O3/HfO2/Al2O3 Tunnel Barrier
- 2009
-
Ingår i: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 26:8, s. 087303-
-
Tidskriftsartikel (refereegranskat)abstract
- An atomic-layer-deposited Al2O3/HfO2/Al2O3 (A/H/A) tunnel barrier is investigated for Co nanocrystal memory capacitors. Compared to a single Al2O3 tunnel barrier, the A/H/A barrier can significantly increase the hysteresis window, i. e., an increase by 9V for +/- 12V sweep range. This is attributed to a marked decrease in the energy barriers of charge injections for the A/H/A tunnel barrier. Further, the Co-nanocrystal memory capacitor with the A/H/A tunnel barrier exhibits a memory window as large as 4.1V for 100 mu s program/erase at a low voltage of +/- 7V, which is due to fast charge injection rates, i. e., about 2.4 x 10(16) cm(-2) s(-1) for electrons and 1.9 x 10(16) cm(-2) s(-1) for holes.
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| 35. |
- Liu, Hong, et al.
(författare)
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Variant selection of primary–secondary extension twin pairs in magnesium : An analytical calculation study
- 2021
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 219, s. 1-19
-
Tidskriftsartikel (refereegranskat)abstract
- Twining is an important deformation mode in magnesium. In a deformed magnesium sample, an extension twin crystal, i.e., {101¯2} twin, can form inside a {101¯2} primary twin, which is named {101¯2}–{101¯2} secondary twin. These secondary twins often appear at the intersection of two primary twins, and form primary–secondary twin pairs. Experimental observations show that the most frequently observed primary–secondary twin pairs have a unique misorientation, i.e., twin variant selection exists. Such variant selection of the primary–secondary twin pairs is studied in this work. The crystallographic analysis reveals that the twin planes of the primary and secondary twins that form a twin pair have coincident intersection lines with the boundary where the twin pair adjoins. An analytical calculation method based on Eshelby's inclusion theory is developed, and the calculation results show that only for this unique misorientation, the stress fields concentrated at the rims of the primary and the secondary twins are mutually favoured. The analysis is further extended to the incoming–outgoing twin pairs across ordinary grain boundaries, and compared with the commonly used geometrical compatibility factor m′. It is found that m′ only gives good prediction for twin transmission when the shear stress component on the twin plane along the twin shear direction of the incoming twin is the major contributor to the resolved shear stress of the outgoing twin. When other stress components play a dominant role, m′ becomes ineffective in prediction, which is the case for the primary–secondary twin pairs.
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| 36. |
- Masselot, Pierre, et al.
(författare)
-
Differential mortality risks associated with PM2.5 components : a multi-country, multi-city study
- 2022
-
Ingår i: Epidemiology. - : Wolters Kluwer. - 1044-3983 .- 1531-5487. ; 33:2, s. 167-175
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The association between fine particulate matter (PM2.5) and mortality widely differs between as well as within countries. Differences in PM2.5 composition can play a role in modifying the effect estimates, but there is little evidence about which components have higher impacts on mortality.METHODS: We applied a two-stage analysis on data collected from 210 locations in 16 countries. In the first stage, we estimated location-specific relative risks (RR) for mortality associated with daily total PM2.5 through time series regression analysis. We then pooled these estimates in a meta-regression model that included city-specific logratio-transformed proportions of seven PM2.5 components as well as meta-predictors derived from city-specific socio-economic and environmental indicators.RESULTS: We found associations between RR and several PM2.5 components. Increasing the ammonium (NH4+) proportion from 1% to 22%, while keeping a relative average proportion of other components, increased the RR from 1.0063 (95%CI: 1.0030-1.0097) to 1.0102 (95%CI:1.0070-1.0135). Conversely, an increase in nitrate (NO3-) from 1% to 71% resulted in a reduced RR, from 1.0100 (95%CI: 1.0067-1.0133) to 1.0037 (95%CI: 0.9998- 1.0077). Differences in composition explained a substantial part of the heterogeneity in PM2.5 risk.CONCLUSIONS: These findings contribute to the identification of more hazardous emission sources. Further work is needed to understand the health impacts of PM2.5 components and sources given the overlapping sources and correlations among many components.
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| 37. |
- Niu, Hong, et al.
(författare)
-
Artificial Noise Elimination : From the Perspective of Eavesdroppers
- 2022
-
Ingår i: IEEE Transactions on Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 0090-6778 .- 1558-0857. ; 70:7, s. 4745-4754
-
Tidskriftsartikel (refereegranskat)abstract
- Artificial noise (AN), aiming to disturb the eavesdropper while avoiding the influence on the legitimate receiver, has arisen as an excellent technology for improving the physical-layer security of wireless communications. In order to challenge AN, zero-forcing elimination (ZFE) has been introduced as a possible countermeasure to mitigate the AN for the eavesdropper at the cost of more available receive antennas. In this contribution, from the perspective of eavesdroppers, we further conceive a class of efficient null-space elimination (NSE) schemes in order to reduce the number of receive antennas while enhancing the detection quality compared to original ZFE. Furthermore, the performance of secrecy rate as well as bit-error rate (BER) is quantified for both ZFE and NSE schemes through theoretical derivation, while the influence of imperfect channel state information (CSI) is also evaluated. The performance comparison of the above-mentioned schemes illustrates that NSE can provide more robust performance for eavesdroppers over ZFE, with lower hardware requirements as well as moderate complexity increase.
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| 38. |
- Niu, Hong, et al.
(författare)
-
On the Efficient Design of RIS-Assisted MIMO Transmission
- 2022
-
Ingår i: 2022 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 2346-2351
-
Konferensbidrag (refereegranskat)abstract
- Recently, reconfigurable intelligent surface (RIS) has arisen as an excellent technology for assisting wireless communications. In order to handle the intractable non-convex problem for jointly optimizing beamforming and PSs in multiple-input multipleoutput (MIMO) transmission, we propose a novel alternating direction (AD) method by maximizing the achievable rate (AR) at the receiver. Specifically, the initial problem is divided into the following two processes: i) optimizing the beamforming vector with fixed PSs, ii) determining a specific PS based on a closedform solution when the other PSs and beamforming are fixed. Simulation results corroborate that the proposed AD method provides robust attainable performance with reduced computational complexity compared to its traditional counterparts.
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| 39. |
- Niu, Hong, et al.
(författare)
-
On the Efficient Design of RIS-Assisted Secure MISO Transmission
- 2022
-
Ingår i: IEEE Wireless Communications Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 2162-2337 .- 2162-2345. ; 11:8, s. 1664-1668
-
Tidskriftsartikel (refereegranskat)abstract
- For the sake of improving the physical-layer security, reconfigurable intelligent surface (RIS) has been suggested to assist artificial noise (AN) to bridge both their advantages in multiple-input single-output (MISO) systems. Specifically, for achieving the trade-off between the reliability and security of transmission, the phase shifts (PSs) and beamforming are jointly designed based on the oblique manifold (OM) algorithm (Wang et al., 2020) without eavesdropper's channel state information (CSI). In order to alleviate the computational complexity, a novel alternating direction (AD) algorithm is proposed in this contribution. Specifically, the initial problem is transformed into several subproblems, each of which determines a specific RIS unit via a closed-form solution when the other configurations are fixed. Furthermore, the AD algorithm is investigated to exhibit the low-complexity advantage in contrast to OM. Simulation results illustrate that AD can converge faster and more stably compared to OM with the same performance.
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| 40. |
- Niu, Hong, et al.
(författare)
-
When the CSI from Alice to Bob is Unavailable : What Can Eve Do to Eliminate the Artificial Noise?
- 2022
-
Ingår i: 2022 IEEE 96TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2022-FALL). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- Artificial noise elimination (ANE) has arisen as a possible countermeasure for mitigating the influence of artificial noise (AN) at the eavesdropper (Eve). However, conventional ANE schemes require the attainable channel state information (CSI) between the transmitter (Alice) and legitimate receiver (Bob), which reduces the feasibility of this proposal. In this paper, we investigate the issue of ANE without the CSI of Alice-Bob link by minimizing the artificial-noise-to-signal ratio (ANSR). Moreover, the detailed minor component analysis (MCA) algorithm is presented, and the computational complexity is quantified. Simulation results demonstrate that MCA can effectively degrade the influence of AN without the knowledge of CSI.
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| 41. |
- Parwal, Arvind, et al.
(författare)
-
Wave Energy Research at Uppsala University and The Lysekil Research Site, Sweden : A Status Update
- 2015
-
Konferensbidrag (refereegranskat)abstract
- This paper provides a summarized status update ofthe Lysekil wave power project. The Lysekil project is coordinatedby the Div. of Electricity, Uppsala University since 2002, with theobjective to develop full-scale wave power converters (WEC). Theconcept is based on a linear synchronous generator (anchored tothe seabed) driven by a heaving point absorber. This WEC has nogearbox or other mechanical or hydraulic conversion systems,resulting in a simpler and robust power plant. Since 2006, 12 suchWECs have been build and tested at the research site located atthe west coast of Sweden. The last update includes a new andextended project permit, deployment of a new marine substation,tests of several concepts of heaving buoys, grid connection,improved measuring station, improved modelling of wave powerfarms, implementation of remote operated vehicles forunderwater cable connection, and comprehensive environmentalmonitoring studies.
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| 42. |
- Qu, Xueqi, et al.
(författare)
-
Socio-emotional challenges and development of children left behind by migrant mothers.
- 2020
-
Ingår i: Journal of global health. - : International Global Health Society. - 2047-2986 .- 2047-2978. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- With great economic development and rapid urbanization in China, left-behind children whose parents migrate to big cities for job has become a large special population which requires more attention. The present study aims to explore the specific influence of migrant mothers on early child development, especially on social-emotional problems.The data of this study was obtained from a cross-sectional study in 8 counties of central and western rural China. Development status of 1880 children aged <60 months were assessed by Ages & Stages Questionnaire-Chinese Edition (ASQ) and the Ages and Stages Questionnaire: Social Emotional-Chinese Edition (ASQ: SE). Multivariate logistic regressions were used to analyze the association between being left behand by migrant mothers and developmental problems in various domains, while adjusting socio-demographic, socio-economic and perinatal co-variates, and effect modification analysis were conducted to explore the effect of age, gender and birth order.Children left behind by migrant mothers were more likely to have overall suspected developmental delay (odds ratio (OR) = 1.24, 95% confidence interval (CI) = 1.13-1.35), developmental delay in personal social domain (OR = 1.55, 95% CI = 1.17-2.04) and socio-emotional delay compared with those living with their own mothers (OR = 1.49, 95% CI = 1.11-2.00) after adjusting for potential confounders. Additionally, girls increased the odds of social-emotional problems among children being left behind by migrating mother (P for interaction = 0.037).The study concluded that children left behind by migrant mothers were more likely to have suspected developmental delay compared with their peers living with mothers, especially on social emotional development. Future intervention is needed for this special population and should pay more attention to girls.
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| 43. |
- Ren, Hong, et al.
(författare)
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Measurement report: Vertical distribution of biogenic and anthropogenic secondary organic aerosols in the urban boundary layer over Beijing during late summer
- 2021
-
Ingår i: ATMOSPHERIC CHEMISTRY AND PHYSICS. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:17, s. 12949-12963
-
Tidskriftsartikel (refereegranskat)abstract
- Secondary organic aerosol (SOA) plays a significant role in atmospheric chemistry. However, little is known about the vertical profiles of SOA in the urban boundary layer (UBL). This knowledge gap constrains the SOA simulation in chemical transport models. Here, the aerosol samples were synchronously collected at 8, 120, and 260m based on a 325m meteorological tower in Beijing from 15 August to 10 September 2015. Strict emission controls were implemented during this period for the 2015 China Victory Day parade. Here, we observed that the total concentration of biogenic SOA tracers increased with height. The fraction of SOA from isoprene oxidation increased with height, whereas the fractions of SOA from monoterpenes and sesquiterpenes decreased, and 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a tracer of anthropogenic SOA from toluene oxidation, also increased with height. The complicated vertical profiles of SOA tracers highlighted the need to characterize SOA within the UBL. The mass concentration of estimated secondary organic carbon (SOC) ranged from 341 to 673 ngC m(-3). The increase in the estimated SOC fractions from isoprene and toluene with height was found to be more related to regional transport, whereas the decrease in the estimated SOC from monoterpenes and sesquiterpene with height was more subject to local emissions. Emission controls during the parade reduced SOC by 4 %-35 %, with toluene SOC decreasing more than the other SOC. This study demonstrates that vertical distributions of SOA within the UBL are complex, and the vertical profiles of SOA concentrations and sources should be considered in field and modeling studies in the future.
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| 44. |
- Shao, Yue, et al.
(författare)
-
All-Poly(ionic liquid) Membrane-Derived Porous Carbon Membranes : Scalable Synthesis and Application for Photothermal Conversion in Seawater Desalination
- 2018
-
Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 12:11, s. 11704-11710
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, we introduce a straightforward, scalable, and technologically relevant strategy to manufacture charged porous polymer membranes (CPMs) in a controllable manner. The pore sizes and porous architectures of CPMs are well-controlled by rational choice of anions in poly(ionic liquid)s (PILs). Continuously, heteroatom-doped hierarchically porous carbon membrane (HCMs) can be readily fabricated via morphology-maintaining carbonization of as-prepared CPMs. These HCMs, as photothermal membranes, exhibited excellent performance for solar seawater desalination, representing a promising strategy to construct advanced functional nanomaterials for portable water production technologies.
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| 45. |
- Shao, Yue, et al.
(författare)
-
Crosslinking of a Single Poly(ionic liquid) by Water into Porous Supramolecular Membranes
- 2020
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 59:39, s. 17187-17191
-
Tidskriftsartikel (refereegranskat)abstract
- Reversible regulation of membrane microstructures via non-covalent interactions is of considerable interest yet remains a challenge. Herein, we discover a general one-step approach to fabricate supramolecular porous polyelectrolyte membranes (SPPMs) from a single poly(ionic liquid) (PIL). The experimental results and theoretical simulation suggested that SPPMs were formed by a hydrogen-bond-induced phase separation of a PIL between its polar and apolar domains, which were linked together by water molecules. This unique feature was capable of modulating microscopic porous architectures and thus the global mechanical property of SPPMs by a rational design of the molecular structure of PILs. Such SPPMs could switch porosity upon thermal stimuli, as exemplified by dynamically adaptive transparency to thermal fluctuation. This finding provides fascinating opportunities for creating multifunctional SPPMs.
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| 46. |
-
The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
-
Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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| 47. |
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| 48. |
- Wang, Hong, et al.
(författare)
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Ambient Electrosynthesis of Ammonia : Electrode Porosity and Composition Engineering
- 2018
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 57:38, s. 12360-12364
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia, a key precursor for fertilizer production, convenient hydrogen carrier, and emerging clean fuel, plays a pivotal role in sustaining life on Earth. Currently, the main route for NH3 synthesis is by the heterogeneous catalytic Haber-Bosch process (N-2+ 3H(2) -> 2NH(3)), which proceeds under extreme conditions of temperature and pressure with a very large carbon footprint. Herein we report that a pristine nitrogen-doped nanoporous graphitic carbon membrane (NCM) can electrochemically convert N-2 into NH3 in an acidic aqueous solution under ambient conditions. The Faradaic efficiency and rate of production of NH3 on the NCM electrode reach 5.2% and 0.08 gm(-2) h(-1), respectively. Functionalization of the NCM with Au nanoparticles dramatically enhances these performance metrics to 22% and 0.36 gm(-2) h(-1), respectively. As this system offers the potential to be scaled to industrial levels it is highly likely that it might displace the century-old Haber-Bosch process.
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| 49. |
- Wang, Hong, et al.
(författare)
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Polymer-Derived Heteroatom-Doped Porous Carbon Materials
- 2020
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 120:17, s. 9363-9419
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Forskningsöversikt (refereegranskat)abstract
- Heteroatom-doped porous carbon materials (HPCMs) have found extensive applications in adsorption/separation, organic catalysis, sensing, and energy conversion/storage. The judicious choice of carbon precursors is crucial for the manufacture of HPCMs with specific usages and maximization of their functions. In this regard, polymers as precursors have demonstrated great promise because of their versatile molecular and nanoscale structures, modulatable chemical composition, and rich processing techniques to generate textures that, in combination with proper solid-state chemistry, can be maintained throughout carbonization. This Review comprehensively surveys the progress in polymer-derived functional HPCMs in terms of how to produce and control their porosities, heteroatom doping effects, and morphologies and their related use. First, we summarize and discuss synthetic approaches, including hard and soft templating methods as well as direct synthesis strategies employing polymers to control the pores and/or heteroatoms in HPCMs. Second, we summarize the heteroatom doping effects on the thermal stability, electronic and optical properties, and surface chemistry of HPCMs. Specifically, the heteroatom doping effect, which involves both single-type heteroatom doping and codoping of two or more types of heteroatoms into the carbon network, is discussed. Considering the significance of the morphologies of HPCMs in their application spectrum, potential choices of suitable polymeric precursors and strategies to precisely regulate the morphologies of HPCMs are presented. Finally, we provide our perspective on how to predefine the structures of HPCMs by using polymers to realize their potential applications in the current fields of energy generation/conversion and environmental remediation. We believe that these analyses and deductions are valuable for a systematic understanding of polymer-derived carbon materials and will serve as a source of inspiration for the design of future HPCMs.
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| 50. |
- Wang, Tongzhou, et al.
(författare)
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Atomically Dispersed Semi-Metallic Selenium on Porous Carbon Membrane as an Electrode for Hydrazine Fuel Cells
- 2019
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 58:38, s. 13466-13471
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemically functional porous membranes of low cost are appealing in various electrochemical devices used in modern environmental and energy technologies. Herein we describe a scalable strategy to construct electrochemically active, hierarchically porous carbon membranes containing atomically dispersed semi-metallic Se, denoted SeNCM. The isolated Se atoms were stabilized by carbon atoms in the form of a hexatomic ring structure, in which the Se atoms were located at the edges of graphitic domains in SeNCM. This configuration is different from that of previously reported transition/noble metal single atom catalysts. The positively charged Se, enlarged graphitic layers, robust electrochemical nature of SeNCM endow them with excellent catalytic activity that is superior to state-of-the-art commercial Pt/C catalyst. It also has long-term operational stability for hydrazine oxidation reaction in practical hydrazine fuel cell.
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