检索结果-南通市图书馆

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

直接甲醇燃料电池中碳基载体材料的研究进展

精细化工 2024年第2期41卷 269-276页

作者：季东安欣郭鹏王首登达虎李红伟兰州理工大学石油化工学院甘肃兰州730050 甘肃省计算中心甘肃兰州730030

甲醇氧化电催化剂是决定直接甲醇燃料电池(DMFCs)性能、寿命与成本的关键。为获得高功率密度和低生产成本的DMFCs,设计合成组成、结构、形貌可控的阳极催化剂备受关注。阳极催化剂的颗粒尺寸、粒径分布、形貌结构、稳定性、分散性以及... 详细信息

甲醇氧化电催化剂是决定直接甲醇燃料电池(DMFCs)性能、寿命与成本的关键。为获得高功率密度和低生产成本的DMFCs,设计合成组成、结构、形貌可控的阳极催化剂备受关注。阳极催化剂的颗粒尺寸、粒径分布、形貌结构、稳定性、分散性以及催化活性都与载体息息相关,而碳基载体材料由于其优异的性能已广泛应用于DMFCs中。首先,介绍了酸性环境和碱性环境中甲醇氧化反应的机理;然后,对不同形式的碳基载体材料,如炭黑、介孔碳、碳纳米材料、氧功能化碳、杂原子掺杂碳以及金属氧化物改性碳作为催化剂载体在DMFCs中的应用进行了综述;最后,对DMFCs的发展趋势进行了展望。

关键词：电化学直接甲醇燃料电池阳极催化剂碳基载体材料机理

维普期刊数据库博看期刊

Anti-osteoarthritis effect of a combination treatment with human adipose tissue-derived mesenchymal stem cells and thrombospondin 2 in rabbits

在线全文

学校读者我要写书评

暂无评论

World Journal of Stem Cells 2019年第12期11卷 1115-1129页

作者： Kyungha Shin Yeseul Cha Young-Hwan Ban da Woom Seo Ehn-Kyoung Choi Dongsun Park Sung Keun Kang Jeong Chan ra Yun-Bae Kim College of Veterinary Medicine Chungbuk National UniversityCheongju 28644ChungbukSouth Korea Department of Biology Education Korea National University of EducationCheongju 28173ChungbukSouth Korea Biostar Stem Cell Research Institute R-BIO Co.Ltd.Seoul 07238South Korea

BACKGROUND Osteoarthritis(OA),a chronic age-related disease characterized by the slowly progressive destruction of articular cartilage,is one of the leading causes of *** a new strategy for treatment of OA,mesenchymal stem cells(MSCs)have the potential for articular cartilage ***,thrombospondin 2(TSP2)promotes the chondrogenic differentiation of *** To investigate whether TSP2 induces chondrogenic differentiation of human adipose-derived MSCs(hADMSCs)and potentiates the therapeutic effects of hADMSCs in OA *** We investigated the chondrogenic potential of TSP2 in hADMSCs by analyzing the expression of chondrogenic markers as well as NOTCH signaling genes in normal and TSP2 small interfering RNA(siRNA)-treated stem *** cruciate ligament transection surgery was performed in male New Zealand white rabbits,and 8 wk later,hADMSCs(1.7×10^6 or 1.7×10^7 cells)were injected into the injured knees alone or in combination with intra-articular injection of TSP2(100 ng/knee)at 2-d *** progression was monitored by gross,radiological,and histological *** In hADMSC culture,treatment with TSP2 increased the expression of chondrogenic markers(SOX9 and collagen Ⅱ)as well as NOTCH signaling genes(JAGGED1 and NOTCH3),which were inhibited by TSP2 siRNA *** vivo,Oa.ra.bits treated with hADMSCs or TSP2 alone exhibited lower degree of cartilage degeneration,osteophyte formation,and extracellular matrix loss 8 wk after cell ***,such cartilage damage was further alleviated by the combination of hADMSCs and *** addition,synovial inflammatory cytokines,especially tumor-necrosis factor-α,markedly decreased following the combination *** The results indicate that TSP2 enhances chondrogenic differentiation of hADMSCs via JAGGED1/NOTCH3 signaling,and that combination therapy with hADMSCs and TSP2 exerts synergistic effects in the cartilage regeneration of OA joints.

关键词： Osteoarthritis Anterior cruciate ligament transection Human adipose tissuederived mesenchymal stem cell Thrombospondin 2 Notch signaling Cartilage regeneration

Epidemiological and Diagnostic Profile of Patients with Chronic Hepatitis B Virus from 2017 to 2021 in Parakou, Republic of Benin

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Infectious Diseases 2024年第1期14卷 147-161页

作者： Khadidjatou Saké Cossi Angelo Attinsounon Aboudou raϊmi Kpossou Morayo Omm Ani Salami Astrid Alexandrine Hountondji Kofi-Mensa Savi de Tovè Rhonel Ahanhanzo-Glèlè Kpémahoun René Kèkè Sossa Edmond Gbédo Jean Sehonou Nicolas Kodjoh Department of Medicine and Medical Specialties Faculty of Medicine University of Parakou Parakou Benin Department of Medicine and Medical Specialties Faculty of Health Sciences University of Abomey-Calavi Cotonou Benin Health Program to Fight AIDS Cotonou Benin National Program for the Control of Hepatitis Cotonou Benin

Introduction: Viral hepatitis B is a public health problem worldwide. The objective of this study was to determine the epidemiological and diagnostic profile of chronic carriers of hepatitis B virus seen for gastroenterology consultations in Parakou, Republic of Benin. Patients and Methods: This was a cross-sectional and descriptive study with retrospective data collection. Patients seen for gastroenterology consultations from January 1, 2017 to June 30, 2021 at the Regional Teaching Hospital of Borgou/Alibori (CHUD-B/A) and having been diagnosed as chronic carriers of hepatitis B virus were included. A minimum initial assessment was required to be included. The minimum sample size was calculated with Schwartz formula. The variable of interest was the detection of HBsAg twice and at least 6 months apart. The other variables studied were sociodemographic, clinical and paraclinical data. The data collected were analyzed using SPSS 17 software. Results: A total of 2786 patients were seen for gastroenterology consultations, including 1126 (40.4%) HBsAg-positive patients. Among them, 417 patients met the inclusion criteria and were the subject of the present study. The average age of the patients was 34.8 ± 10.5 years. Two hundred and forty-seven patients (65.7%) were male, representing a sex ratio of 1.9. The discovery of positive HBsAg status was made during systematic screening in 231 patients (55.4%). Scarifications were noted in 373 patients (89.4%). Asthenia was reported in 184 patients (44.1%). Co-infections with human immunodeficiency virus, hepatitis C and D viruses were 0% (0 in 92), 2.8% (4 in 146) and 14.3% (2 in 146), respectively. During the initial assessment, 274 patients (65.7%) were sero-negative for chronic HBeAg infection, 21 (5%) had clinically significant fibrosis including 16 (3.8%) at the stage of cirrhosis and 7 patients (5.4%) had hepatocellular carcinoma. Conclusion: In Parakou, chronic hepatitis B virus infection is common and affects young pe

关键词： Chronic Infection HBV Epidemiology Diagnosis Parakou

Emphysematous Cystitis: Report of Two Cases and Review of the Literature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Health 2024年第4期16卷 309-318页

作者： Roland Bertile Banga-Mouss Nestor Ghislain Andzouana Mbamognoua Yanick Dimi Nyanga Armel Melvin Atipo Ondongo Steve Aristid Ondziel-Opara.ra.ssa laure Mayanda Ohouanda Nick Arnaud Monabeka Evariste Bouenizabila Anani Séverin Wences Odzébé Prosper Alain Bouya Urology Department University Hospital of Brazzaville Brazzaville Republic of the Congo Faculty of Health Sciences Marien Ngouabi University Brazzaville Republic of the Congo Department of Metabolic and Endocrine Diseases University Hospital of Brazzaville Brazzaville Republic of the Congo

Emphysematous cystitis is a.ra.e complication of lower urinary tract infection whose prognosis is conditioned by the delay in treatment. The predisposition of diabetic patients to urinary infections caused by gas-producing bacteria is considered one of the most common factors in the occurrence of emphysematous cystitis. The currently recommended diagnostic test is CT scanning, which has definite value in assessing gas accumulation in the bladder wall and lumen. The authors report the observations of two patients aged 68 and 80 who were treated for emphysematous cystitis complicating diabetes mellitus. The evolution was favorable under treatment with antibiotic therapy, insulin therapy and bladder drainage.

关键词： Emphysematous Cystitis Computed Tomography Lower Urinary Tract Infection Diabetes Mellitus

Variations in productivity and wood properties of Amazonian tachi-branco trees planted at diff erent spacings for bioenergy purposes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2021年第1期32卷 211-224页

作者： Marilene Olga dos Santos Silva Marcela Gomes da Silva Lina Bufalino Ma.ra.Reis de Assis Delman de Almeida Goncalves Paulo Fernando Trugilho Thiago de Paula Protásio Rural Federal University of Amazonia/UFra Perimetral Ave.Terra FirmeBelémPA 66077-830Brazil Federal University of La.ra./UFla Francisco Sales St.CentroLavrasMG 37200-000Brazil Brazilian Agricultural Research Corporation/Eastern Amazonia Embrapa Dr.Enéas Pinheiro BySt.MarcoBelémPA 66095-903Brazil Rural Federal University of Amazonia/UFra PA-275 Rd.Zona RuralParauapebasPA 68515-000Brazil

Marilene Olga dos Santos Silva 1·Marcela Gomes da Silva 1·LTachi-branco(Tachigali vulgaris,*** da Silva&***)is a leguminous tree species native to the Amazon rainforest that has drawn attention for its remarkably fast growth,a required trait for biomass/bioenergy *** evaluations of biomass production and wood properties of *** planted in homogeneous plantations at diff erent spacings in the Amazonian state of Pará,Brazil,biomass of 7-year-old trees was quantifi ed for individual trees and the entire *** was also sampled to assess properties relevant to bioenergy *** choice for spacing dimension for planting nonclonal *** should consider whether the priority is greater productivity per tree,achieved with greater spacings(9.0 m 2 and 12.0 m 2),or productivity per area,achieved with closerina Bufalino 1·Ma.ra.Reis de Assis 2·Delman de Almeida Goncalves 3·Paulo Fernando Trugilho 2·Thiago de Paula Protásio 4 spacings(6.0 m 2 and 7.5 m 2).Genetic variability of the *** seed stand and/or high heritability of wood traits overcame the eff ect of diff erent spacing on all morphological,physical,chemical and energetic properties of *** *** species has moderate basic density when cultivated at spacings larger than 6 m 2 and net heating value above 7.95 MJ/kg,which is suitable for bioenergy *** high variation in wood properties within tree spacing is strongly indicative of great potential for genetic *** fast growth and the suitable moderate wood basic density confi rm the outstanding potential of homogeneous plantations of *** for providing wood for bioenergy.

关键词： Basic density Heating value Planting density Tachigali vulgaris

维普期刊数据库

Soil quality assessment for desertification based on multi-indicators with the best-worst method in a semi-arid ecosystem

在线全文

学校读者我要写书评

暂无评论

Journal of Arid land 2023年第7期15卷 779-796页

作者： Orhan DENGİZ İnci DEMİraĞTUraN Department of Soil Science and Plant Nutrition Faculty of AgricultureOndokuz Mayıs UniversitySamsun-55139Turkey Department of Geography Faculty of EconomicAdministrative and Social SciencesSamsun UniversitySamsun-55030Turkey

Since there are some signs of land degradation and desertification showing how soil sustainability is threatened, it is crucial to create a soil quality index(SQI) model in the semi-arid ?orum Basin, situated between the Black Sea and Anatolia Region, Central Turkey. The primary aims of the study are:(1) to determine SQI values of the micro-basin in terms of land degradation and ***, the best-worst method(BWM) was used to determine the weighting score for each parameter;(2) to produce the soils' spatial distribution by utilizing different geostatistical models and GIS(geographic information system) techniques;and(3) to validate the obtained SQI values with biomass reflectance values. Therefore, the relationship of RE-OSAVI(red-edge optimized soil-adjusted vegetation index) and NDVI(normalized difference vegetation index) generated from Sentinel-2A satellite images at different time series with soil quality was examined. Results showed that SQI values were high in the areas that had almost a flat and slight slope. Moreover, the areas with high clay content and thick soil depth did not have salinity problems, and were generally distributed in the middle parts of the basin. However, the areas with a high slope, poor vegetation, high sand content, and low water holding capacity had low SQI ***, a statistically high positive correlation of RE-OSAVI and NDVI indices with soil quality was found, and NDVI had the highest correlative value for June(R~2=0.802) compared with RE-OSAVI.

关键词： soil quality land degradation desertification best-worst method remote sensing

维普期刊数据库

ROBUST HIGH ORDER CONVERGENCE OF AN OVERlaPPING SCHWARZ METHOD FOR SINGUlaRLY PERTURBED SEMILINEAR REACTION-DIFFUSION PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2013年第5期31卷 509-521页

作者： S. Chandra Sekhara.ra. Sunil Kumar Department of Mathematics Indian Institute of Technology Delhi Hauz khas New Delhi-110016 India

In this article we propose an overlapping Schwarz domain decomposition method for solving a singularly perturbed semilinear reaction-diffusion problem. The solution to this problem exhibits boundary layers of width O（√ε ln（1/√ε）） at both ends of the domain due to the presence of singular perturbation parameter ε. The method splits the domain into three overlapping subdomains, and uses the Numerov or Hermite scheme with a uniform mesh on two boundary layer subdomains and a hybrid scheme with a uniform mesh on the interior subdomain. The numerical approximations obtained from this method are proved to be almost fourth order uniformly convergent （in the maximum norm） with respect to the singular perturbation parameter. Furthermore, it is proved that, for small ε, one iteration is sufficient to achieve almost fourth order uniform convergence. Numerical experiments are given to illustrate the theoretical order of convergence established for the method.

关键词： Singular perturbation Semilinear reaction-diffusion Overlapping Schwarzmethod Robust convergence Numerov scheme.

Periodic Solutions of Evolution Variational Inequalities—a Method of Guiding Functions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2009年第3期30卷 261-272页

作者： Samir ADLY daniel GOELEVEN Michel THra Département de Math'ematiques et Informatique Laboratoire XLIM(Unité Mixte 6172 du CNRS)Université de Limoges123 Avenue A.Thomas87060 Limoges CedexFrance. laboratoire d' Informatique et de Mathématiques Université de La Réunion97400 Saint-DenisFrance.

This paper focuses on a part of the presentation given by the third author at the Shanghai Forum on Industrial and Applied Mathematics(Shanghai 2006).It is related to the existence of a periodic solution of evolution ... 详细信息

关键词： Variational inequality Differential inclusion Topological degree Guiding function Periodic solution

维普期刊数据库

Future prospectives for the management of chronic hepatitis B

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2007年第18期13卷 2554-2567页

作者： WF Leemans Hla Janssen ra de Man Department of Gastroenterology & Hepatology Erasmus MC University Medical Center Rotterdam The Netherlands

Chronic hepatitis B virus infection affects about 400 million people around the globe and causes approximately a million deaths a year. Since the discovery of interferon-α as a therapeutic option the treatment of hepatitis B has evolved fast and management has become increasingly complicated. The amount of viral replication reflected in the viral load （HBV-DNA） plays an important role in the development of cirrhosis and hepatocellular carcinoma. The current treatment modalities for chronic hepatitis B are immunomodulatory （interferons） and antiviral suppressants （nucleoside and nucleotide analogues） all with their own advantages and limitations. An overview of the treatment efficacy for both immunomodulatory as antiviral compounds is provided in order to provide the clinician insight into the factors influencing treatment outcome. With nucleoside or nucleotide analogues suppression of viral replication by 5-7 log10 is feasible, but not all patients respond to therapy. Known factors influencing treatment outcome are viral load, ALT levels and compliance. Many other factors which might influence treatment are scarcely investigated. Identifying the factors associated with response might result in stopping rules, so treatment could be adapted in an early stage to provide adequate treatment and avoid the development of resistance. The efficacy of compounds for the treatment of mutant virus and the cross-resistance is largely unknown. However, genotypic and phenotypic testing as well as small clinical trials provided some data on efficacy in this population. Discontinuation of nucleoside or nucleotide analogues frequently results in viral relapse; however, some patients have a sustained response. data on the risk factors for relapse are necessary in order to determine when treatment can be discontinued safely. In conclusion： chronic hepatitis B has become a treatable disease; however, much research is needed to tailor therapy to an individual patient, to predict the susta

关键词： Hepatitis B virus Cirrhosis Treatment Interferon Nucleoside analogues Nucleotide analogues lamivudine Adefovir Entecavir Telbivudine Tenofovir Resistance Genotype