检索结果-南通市图书馆

腐植酸 2010年第3期 26-34页

作者： sheela g. agrawal Ryan L. Fimmen Yuping Chin 胡顺利方莉俄亥俄州立大学地球科学学院门登霍尔实验室哥伦布43210 大连理工大学环境与生命学院大连116024 中国腐植酸工业协会北京100120

考查了缺氧条件下Fe(Ⅱ)-有机质(DOM)的络合物将Cr(Ⅵ)还原为Cr(Ⅲ)的还原能力。研究发现在没有或有萨旺尼河黄腐酸(SRFA)和波尼湖黄腐酸(PLFA)存在的情况下,Fe(Ⅱ)都能够将Cr(Ⅵ)快速地还原(几分钟)。Fe(Ⅱ)-DOM溶液不一定比仅含有Fe(... 详细信息

考查了缺氧条件下Fe(Ⅱ)-有机质(DOM)的络合物将Cr(Ⅵ)还原为Cr(Ⅲ)的还原能力。研究发现在没有或有萨旺尼河黄腐酸(SRFA)和波尼湖黄腐酸(PLFA)存在的情况下,Fe(Ⅱ)都能够将Cr(Ⅵ)快速地还原(几分钟)。Fe(Ⅱ)-DOM溶液不一定比仅含有Fe(Ⅱ)单一的体系具有更强的还原力。DOM的组成也影响了Cr(Ⅲ)的还原机制,湿地(俄亥俄州老妇人河河口区)沉积物进行缺氧萃取得到的沉积物孔隙水能够将Cr(Ⅵ)更快地还原。这些研究数据表明自然界中富含Fe(Ⅱ)和DOM的缺氧孔隙水对Cr(Ⅵ)的非生物还原反应速率远大于生物还原反应速率,并且这一非生物还原反应是自然环境中Cr(Ⅵ)被还原的主要途径。

关键词： Fe(Ⅱ) Cr(Ⅳ) 还原溶解性有机质黄腐酸

Efficient Packet Scheduling Technique for Data Merging in Wireless Sensor Networks

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

China Communications 2017年第4期14卷 35-46页

作者： V.Akila T.sheela g.Adiline Macriga Computer Science and Engineering Bharath University Chennai India Information Technology Sri Sai Ram Engineering College Chennai India

Wireless Sensor Networks(WSNs) has become a popular research topic due to its resource constraints. Energy consumption and transmission delay is crucial requirement to be handled to enhance the popularity of WSNs. In order to overcome these issues, we have proposed an Efficient Packet Scheduling Technique for Data Merging in WSNs. Packet scheduling is done by using three levels of priority queue and to reduce the transmission delay. Real-time data packets are placed in high priority queue and Non real-time data packets based on local or remote data are placed on other queues. In this paper, we have used Time Division Multiple Access(TDMA) scheme to efficiently determine the priority of the packet at each level and transmit the data packets from lower level to higher level through intermediate nodes. To reduce the number of transmission, efficient data merge technique is used to merge the data packet in intermediate nodes which has same destination node. Data merge utilize the maximum packet size by appending the merged packets with received packets till the maximum packet size or maximum waiting time is reached. Real-time data packets are directly forwarded to the next node without applying data merge. The performance is evaluated under various metrics like packet delivery ratio, packet drop, energy consumption and delay based on changing the number of nodes and transmission rate. Our results show significant reduction in various performance metrics.

关键词： wireless sensor networks data aggregation packet scheduling time division multiple access

In vitro evaluation of anti-acetylcholinesterase and free radical scavenging potential of leaf extracts of some selected medicinal plants

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2019年第2期9卷 60-65页

作者： Annie Jessica Toppo sheela Chandra Dhruv Jha Papiya Mitra Mazumder Department of Bio-Engineering Birla Institute of Technology Department of Pharmaceutical Sciences and Technology Birla Institute of Technology

Objective: To evaluate the phytochemical present in various solvent extracts from leaves of Ocimum sanctum(L.), Swertia chirayita(L.), Butea monosperma(Lam.) and Stevia rebaudiana(Bert.) as well as antioxidant and anticholinergic activities employing different in vitro models. Methods: Total phenol content of diethyl ether, chloroform and methanolic extracts obtained from leaves of different medicinal plants was determined by Folin-Ciocalteau's spectrophotometric method. Moreover, antioxidant and anticholinergic studies were conducted by four different in vitro methods which included diphenyl picrylhydrazyl radical scavenging, 2,2-azinobis(3-ethylbezoline-6-sulphonic acid), reducing activity by ferrous reduced antioxidant power and anti-acetylcholinesterase assay, in order to ensure pharmacological potential of the plants. Results: The methanolic leaf extract of Ocimum sanctum showed the highest total phenol content which was(21.13±1.04) gAE/g DW and antioxidant activities compared to other plants with the IC50 value of 40.43 μg/mL in diphenyl picrylhydrazyl radical scavenging assay and 53.5 μg/mL in 2,2-azinobis(3-ethylbezoline-6-sulphonic acid) assay as well as metal ion reduced by(78.22±0.38) TE/g DW in ferrous reduced antioxidant power assay. The inhibition percentage of the anti-acetylcholinesterase assay was(94.22±0.26)%. Conclusions: The results of our current study show that Ocimum sanctum leaf is the most significant source of phytochemicals that possesses antioxidant and anticholinergic properties. However, further investigation on isolation and characterization of active compound which is responsible for the pharmacological potential is needed.

关键词： DPPH assay Antioxidant Free radical Anti-acetylcholinesterase Phenolics content

Synthesis and characterization of multifunctional ZnBr_(2)/PVA polymer dielectrics

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 Advanced Dielectrics 2016年第4期6卷 22-30页

作者： Jagadish Naik R.F.Bhajantri Sunil g.Rathod T.sheela V.Ravindrachary Department of Physics Mangalore University Mangalagangotri-574199KarnatakaIndia Department of Physics Karnatak University Pavate NagarDharwad-580003KarnatakaIndia

Different weight percentage of ZnBr_(2) doped poly(vinyl alcohol)(PVA)free standing composite films were prepared using solution casting *** films were characterized for analyzing structural,dielectric,electrochemical *** paper mainly focused to understand the contribution of physical phenomenon on conductivity in terms of dielectric *** spectrum confirms the interaction between ZnBr_(2) and ***-capacitive behavior observed from cyclic *** properties of the composites follow non-Debye type *** conducting phenomenon occurs due to hopping of ions between coordination sites present in the composite and the segmental relaxation of polymer chain.

关键词： Poly(vinyl alcohol) polymer electrolytes cyclic voltametry dielectrics zinc bromide.

Attenuation of MET-mediated migration and invasion in hepatocellular carcinoma cells by SOCS1

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of gastroenterology 2017年第36期23卷 6639-6649页

作者： Yirui gui Md gulam Musawwir Khan Diwakar Bobbala Claire Dubois sheela Ramanathan Caroline Saucier Subburaj Ilangumaran Department of Pediatrics Immunology DivisionFaculty of Medicine and Health SciencesUniversity of Sherbrooke Department of Anatomy and Cell Biology Faculty of Medicine and Health SciencesUniversitéde Sherbrooke

AIM To investigate the role of suppressor of cytokine signaling 1(SOCS1)in regulating MET-mediated invasive potential of hepatocellular carcinoma(HCC)*** derivatives of mouse(Hepa1-6)and human(hep3B,Hep g2)HCC cell lines expressing SOCS1or control vector were evaluated for their ability to migrate towards hepatocyte growth factor(HgF)in the transwell migration assay,invade extracellular matrix in response to HgF stimulation in a 3-D invasion assay by confocal microscopy,and to undergo anchorageindependent proliferation in semisolid *** intravenous and intrasplenic inoculation into *** mice,the ability of Hepa cells to form othotopic tumors was *** HgF stimulation of Hepa and Hep3B cells,expression of proteins implicated in epithelial-to-mesenchymal transition was evaluated by western blot and qR *** SOCS1 expression in mouse and human HCC cells inhibited HgF-induced migration through *** the 3-D invasion assay,HgF stimulation induced invasion of HCC cells across type-Ⅰcollagen matrix,and SOCS1expression significantly reduced the depth of ***1 expression also reduced the number and size of colonies formed by anchorage-independent growth in semisolid *** intravenous inoculation,control Hepa cell formed large tumor nodules that obliterated the liver whereas the SOCS1-expressing Hepa cells formed significantly smaller *** formed by SOCS1-expressing cells showed reduced phosphorylation of STAT3 and ERK that was accompanied by reduced levels of MET protein *** stimulated Hepa cells expressing SOCS1 showed increased expression of E-cadherin and decreased expression of EgR1,SNAI1and *** results were obtained with Hep3B ***1 expressing HCC cells also showed reduced levels of EgR1 and SNAI1 *** Our findings indicate that loss of SOCS1-dependent control over epithelial-to-mesenchymal transition may contribute to MET-mediated m

关键词： Migration Invasion MET Hepatocellular carcinoma Suppressor of cytokine signaling 1

A pilot study of the association between genetic polymorphisms involved in estrogen signaling and infant male genital phenotypes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2012年第5期14卷 766-772页

作者： sheela Sathyanarayana Shanna H Swan Federico M Farin Hui-Wen Wilkerson Michael Bamshad Richard grady Chuan Zhou Stephen M Schwartzy Department of Pediatrics University of WashingtonSeattleWA 98195USA Center for Child Health Behaviorand DevelopmentSeattle Children's Research InstituteSeattleWA 98105USA Department of Preventive Medicine Mount Sinai School of MedicineNew YorkNY 10029USA Department of Environmental and Occupational Health Sciences University of WashingtonSeattleWA 98195USA Department of genome Sciences University of WashingtonSeattleWA 98195USA Division of Pediatric Urology Seattle Children's HospitalSeattleWA 98105USA Department of Epidemiology University of WashingtonSeattleWA 98195USA Epidemiology Program Fred Hutchinson Cancer Research CenterSeattleWA 98109USA

Single nucleotide polymorphisms （SNPs） in genes that influence development of the male reproductive tract have been associated with male genitourinary abnormalities. However, no studies have tested the relationship between SNPs and intermediate phenotypes such as anogenital distance （AgD）, anoscrotal distance （ASD） and penile width （PW）. We tested whether 24 common SNPs in eight genes that influence male genital development were associated with intermediate phenotypes in 106 healthy male infants from the Study for Future Families. We used DNA from buccal smears and linear regression models to assess the relationship between anogenital measurements and SNP genotypes with adjustment for covariates. We found that the rs2077647 g allele, located in the coding region of estrogen receptor alpha （ESR1）, was associated with a shorter AgD （P=0.02; -7.3 mm, 95% confidence interval （CI）： -11.6 to -3.1）, and the rs10475 T allele, located in the 3＇ untranslated region of activating transcription factor 3 （ATF3）, was associated with a shorter ASD （-4.3 mm, 95% Ch -7.2 to -1.4）, although this result was not significant （P=0.07） after controlling for multiple comparisons. We observed no association between PW and the SNPs tested. Minor alleles for two SNPs in genes that regulate estrogen signaling during male genital development were associated with AgD and ASD, although the significance of the association was marginal. Our findings suggest that AgD and ASD are influenced by heritable factors in genes known to be associated with frank male genital abnormalities such as hvpospadias and crvotorchidism.

关键词： gene hypospadias male phenotype polymorphism reproductive

Ionic conductivity and dielectric studies of LiClO_(4)doped poly(vinylalcohol)(PVA)/chitosan(CS)composites

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 Advanced Dielectrics 2014年第4期4卷 50-56页

作者： Sunil g.Rathod R.F.Bhajantri V.Ravindrachary P.K.Pujari T.sheela Department of Physics Mangalore University Mangalagangotri 574199KarnatakaIndia Department of Physics Karnatak UniversityPavate Nagar Dharwad 580003KarnatakaIndia Radiochemistry Division Bhabha Atomic Research Centre TrombayMumbai 400085MaharastraIndia

This paper focuses on the dielectric constant("0),dielectric loss factor("00)and frequency dependent conductivity(ac)properties of newly prepared poly(vinylalcohol)(PVA)chitosan(CS)composite films incorporated with different concentrations of LiClO_(4).The composite films were prepared using solution casting *** complexation between salt and polymer host is confirmed by FT Raman and UV-Vis *** sample containing 20 wt.%LiClO_(4)exhibits a highest ionic conductivity of 3106 S/cm at room *** dielectric properties of the composites follow non-Debye behavior.

关键词： Poly(vinylalcohol) chitosan dielectric properties conductivity

母亲颗粒物空气污染暴露与足月出生体重:效应与异质性的多国评估

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

环境与职业医学 2013年第6期30卷 470-470页

作者： Payam Dadvand Jennifer Parker Michelle L. Bell Matteo Bonzini Michael Brauer Lyndsey A. Darrow Ulrike gehring Svetlana V. glinianaia Nelson gouveia Eun-hee Ha Jong Han Leem Edith H. van den Hooven Bin Jalaludin Bill M. Jesdale Johanna Lepeule Rachel Morello-Frosch geoffrey g. Morgan Angela Cecilia Pesatori Frank H. Pierik Tanja Pless-Mulloli David Q. Rich sheela Sathyanarayana Juhee Seo Rémy Slama Matthew Strickland Lillian Tamburic Daniel Wartenberg Mark J. Nieuwenhuijsen Tracey J. Woodruff

[背景]越来越多的证据显示,母亲空气污染暴露与对胎儿生长的不良影响之间存在关联;但是,现有的文献并不一致。[目的]研究9个国家14个中心的数据,量化母亲颗粒物空气污染暴露与足月出生体重和低出生体重(LBW)之间的关联,并探讨此关联中... 详细信息

[背景]越来越多的证据显示,母亲空气污染暴露与对胎儿生长的不良影响之间存在关联;但是,现有的文献并不一致。[目的]研究9个国家14个中心的数据,量化母亲颗粒物空气污染暴露与足月出生体重和低出生体重(LBW)之间的关联,并探讨此关联中地点特征和暴露评估方法对中心之间异质性的影响。[方法]空气污染与妊娠结局国际合作(ICAPPO)的各中心采用共同的分析方案,对PM10和PM2.5(颗粒物≤10和2.5μm)与足月LBW和连续出生体重进行效应评估。采用meta分析将各个中心(~300万例出生)的效应评估结合起来,并采用meta回归分析在报告的效应评估中,中心特征和暴露评估方法对中心之间异质性的影响。[结果]随机效应meta分析显示,调整母亲的社会经济地位后,在整个妊娠期间,足月LBW与PM10[比值比(OR)=1.03;95%CI:1.01~1.05]和PM2.5[OR=1.10;95%CI:1.03~1.18]每增加10μg/m3呈正相关。在充分调整随机效应的meta分析中,作为一个连续性的结果,PM10暴露每增加10μg/m3与足月出生体重呈负相关(-8.9g;95%CI:-13.2^-4.6 g)。meta回归分析显示,具有较高平均PM2.5水平和PM2.5∶PM10比率的中心,以及采用时间暴露评估(与时空相比)的中心,所报告的关联更强。[结论]在研究人群中,母亲颗粒物污染暴露与足月LBW相关联。有3个地点特征和暴露评估方法学方面的不同导致各个中心报告的关联的差异。

关键词：空气污染胎儿生长异质性 ICAPPO 低出生体重 meta分析 meta回归多中心研究颗粒物妊娠