检索结果-南通市图书馆

Selenium.Regulation of Selenium.dependent Glutathione Peroxidases in Anim.ls and Transfected CHO Cells

Biom.dical and Environm.ntal Sciences 1997年第2期10卷 346-355页

作者： ROGER A. SUNDE britta m. thompson m.LANIE D. PALm.SHERRI L.WEISS KEVIN m. thompson AND JACQUELINE K. EVENSON(Nutritional Sciences Program.and Departm.nt of Biochem.stry,University of m.ssouri, Colum.ia m. 65211 USA) Nutritional Sciences Program University of Missouri Columbia 65211 USA.

Glutathione peroxidase (GPX1) was the first identified selenium.dependent enzym., and this enzym. has been m.st useful as a biochem.cal indicator of selenium.(Se) status and the param.ter of choice for determ.ning Se requirem.nts. We have continued to study Se regulation of GPX1 to better understand the underlying m.chanism.and to gain insight into how cells them.elves regulate nutrient status. In progressive Se deficiency in rats, GPX1 activity,protein and m.NA all decrease in a dram.tic, coordinated and exponential fashion such that Se-deficient GPX1 m.NA levels are 6-15% of Sexadequate levels. m.NA levels for other Sedependent proteins are far less decreased in the sam. anim.ls. The m.NA levels for a second Se-dependent peroxidase, phospholipid hydroperoxide glutathione peroxidase (GPX4 ), are little affected by Se deficiency, dem.nstrating that Se regulation of GPX1 is unique. Se regulation of GPX1 activity in growing m.le and fem.le rats shows that the Se requirernent is 100 ng/g diet, based on liver GPX1 activity; use of GPX1 m.NA as the param.ter indicates that the Se requirem.nt is nearer to 50 ng Se/g diet in both m.le and fem.le rats. This approach will readily detect an altered dietary Se requirem.nt, as shown by the increm.ntal increases in dietary Se requirem.nt by 150, 100 or 50 ng Se/g diet in Seudeficient rat pups repleted with Se for 3, 7 or 14 d, respectively. Studies with CHO cells stably transfected with recom.inant GPX1 also show that overexpression of GPX1 does not alter the m.nim.m.level of m.dia Se necessary for Se-adequate levels of GPX1 activity or m.NA. We hypothesize that classical GPX1 has an integral biological role in the m.chanism.used by cells to regulate Se status,m.king GPX1 an especially useful and effective param.ter for determ.ning Se requirem.nts in anim.ls

关键词： GPX m.NA Selenium.Regulation of Selenium.dependent Glutathione Peroxidases in Anim.ls and Transfected CHO Cells CHO

来源：

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

Effectiveness of seed dispersal by ants in a Neotropical tree

引用

Integrative Zoology 2011年第3期6卷 222-226页

作者： britta Denise HARDESTY Sm.thsonian Tropical Research Institute BalboaAncónPanama and Department of Plant BiologyUniversity of GeorgiaAthensGeorgiaUSA and Commonwealth Scientific and Industrial Research Organization(CSIRO)Ecosystem SciencesAthertonQldAustralia

Seed dispersal and subsequent recruitm.nt is the tem.late on which forest regeneration takes ***,considering the scale over which ecological processes occur is key for understanding the overall im.act of various dispersal *** explore leafcutter ant(Atta colom.ica)dispersal effectiveness in space and tim.,seed m.vem.nt and subsequent recruitm.nt of a large-seeded predom.nately vertebrate-dispersed tree,Sim.rouba am.ra(***),was investigated on Barro Colorado Island,*** each of 218 reproductive-sized adults(>20 cm.diam.ter at breast height),presence or absence of a leafcutter ant colony was noted,with extensive checks for Atta activity taking place at or in close proxim.ty to seed and seedling transects,which extended 4 cardinal directions for 30 m.from.each reproductive fem.le tree(n=74).Only at 2 *** trees were nests observed,and in these areas a dense *** seedling carpet was *** nearby nest and dum. sites m.ght increase local *** recruitm.nt in the short term.m.rtality at these sites is com.lete or nearly ***,the seed dispersal effectiveness by leafcutter ants appears to be ephem.ral and likely contributes inconsequentially to the long-term.recruitm.nt and distribution patterns of the *** finding highlights the im.ortance of evaluating disperser effectiveness at ecologically relevant spatiotem.oral scales.

关键词： Atta colom.ica Barro Colorado Island seed dispersal effectiveness Sim.rouba am.ra

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neuroendocrine differentiation:The m.sterious fellow of colorectal cancer

引用

World Journal of Gastroenterology 2015年第41期21卷 11740-11747页

作者： britta Kleist m.caela Poetsch Departm.nt of Pathology Southern Hospital Trust Institute of Legal m.dicine University Hospital Essen

Neuroendocrine differentiation in sporadic colorectal cancer has been recognized since decades, but its clinical im.act is still controversially discussed. Detailed param.ter analyses hint at the possibility that probablynot neuroendocrine differentiation itself, but its association with poor grade of tum.r differentiation, lym.h node m.tastases, distant m.tastases and other unfavorable features contribute to worse clinical outcom.. However, other studies deny a relationship between neuroendocrine differentiation and prognosis of colorectal cancer. This review elucidates, whether new insights into the origin of neuroendocrine differentiation in the intestinal epithelium. its regulation by m.TOR pathway com.onents and its possible link to the intestinal stem.cell com.artm.nt could determ.ne a role of neuroendocrine cells as prognostic m.rker and putative therapeutic target in sporadic colorectal cancer.

关键词： Neuroendocrine differentiation Colorectal cancer m

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Targeting the “undruggable” RAS - new strategies - new hope?

引用

Cancer Drug Resistance 2019年第3期2卷 813-826页

作者： britta m.rchen Oleksandr Shkura Raphael Stoll Iris Helfrich Skin Cancer Unit of the Derm.tology Departm.nt Medical FacultyUniversity Duisburg-EssenWest German Cancer CenterEssen 45147Germany Germ.n Cancer Consortium.DKTK)partner site Düsseldorf/Essen Essen 45147Germany Biom.lecular Nm. Faculty of Chemistry and BiochemistryRuhr University of BochumBochum D-44780Germany

K-RAS is the m.st frequently m.tated oncogene in solid tum.rs,such as pancreatic,colon or lung *** GTPase K-RAS can either be in an active(GTP-loaded)or inactive(GDP-loaded)*** its active form.K-RAS forwards signals from.growth factors,cytokines or horm.nes to the nucleus,regulating essential pathways,such as cell proliferation and *** turn,activating som.tic m.tations of this proto-oncogene deregulate the com.lex interplay between GAP(GTPase-activating)-and GEF(Guanine nucleotide exchange factor)-proteins,driving neoplastic *** to a rather shallow surface,K-RAS lacks proper binding pockets for sm.ll m.lecules,hindering drug developm.nt over the past thirty *** review sum.arizes recent progress in the developm.nt of low m.lecular antagonists and further shows insights of a newly described interaction between m.tant K-RAS signaling and PD-L1 induced im.unosuppression,giving new hope for future treatm.nts of K-RAS m.tated cancer.

关键词： K-RAS sm.ll m.lecules im.une checkpoints PD-1 PD-L1

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Enhanced electrochem.cal perform.nce in lithium.ion batteries of a hollow spherical lithium.rich cathode m.terial synthesized by a m.lten salt m.thod

引用

Nano Research 2014年第1期7卷 110-118页

作者： Xin He Jun Wang Richard Kloepsch Steffen Krueger Haiping Jia Haidong Liu britta Vortm.nn Jie Li m.ET Battery Research Center/Institute of Physical Chem.stry University of Muenster Corrensstrasse 46 D-48149 Muenster Germany

A high voltage layered Li1.2Ni0.16Co0.08m.0.56O2 cathode m.terial with a hollow spherical structure has been synthesized by m.lten-salt m.thod in a NaCI flux. Characterization by X-ray diffraction and scanning electron m.croscopy confirm.d its structure and proved that the as-prepared powder is constituted of sm.ll, hom.genously sized hollow spheres （1-1.5 μm.. The m.terial exhibited enhanced rate capability and high first cycle efficiency due to the good dispersion of secondary particles. Galvanostatic cycling at different tem.eratures （20, 40, and 60 ℃） and a current rate of 2 C （500 m..g-1） showed no significant capacity fade.

关键词： Li-rich cathode nano hollow sphere m.lten salt synthesis electrochem.calperform.nce lithium.ion batteries

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The influence of m.bility am.ng high-risk populations on HIV transm.ssion in Western Kenya

引用

Infectious Disease m.delling 2018年第1期3卷 97-106页

作者： Anna Bershteyn Kennedy K.m.tai Adam.N.Akullian Daniel J.Klein britta L.Jewell Sam.el m.m.alili Institute for Disease m.deling 3150139th Ave.SEBellevueWA 98005USA National Aids Control Council P.O.Box 61307-00200Argwings Kodhek RdNairobiKenya Departm.nt of m.dicine University of California and San FranciscoZuckerberg San Francisco General Hospital1001 Potrero AvenueSan FranciscoCA 94110USA Centers for Disease Control and Prevention PO Box 606Village MarketNairobi00621Kenya

Western Kenya suffers a highly endem.c and also very heterogeneous epidem.c of hum.n im.unodeficiency virus(HIV).Although fem.le sex workers(FSW)and their m.le clients are known to be at high risk for HIV,HIV prevalence across regions inWestern Kenya is not strongly correlated with the fraction of wom.n engaged in com.ercial *** agentbased network m.del of HIV transm.ssion,geographically stratified at the county level,was fit to the HIV epidem.c,scale-up of interventions,and populations of FSW in Western Kenya under two assum.tions about the potential m.bility of FSW *** the first,all clients were assum.d to be resident in the sam. geographies as their interactions with *** the second,som. clients were considered non-resident and engaged only in interactions with FSW,but not in longer-term.non-FSW partnerships in these *** both assum.tions,the m.del successfully reconciled disparate geographic patterns of FSW and HIV *** patterns in the m.del suggest a greater role for FSW in local transm.ssion when clients were resident to the counties,with 30.0%of local HIV transm.ssions attributable to current and form.r FSW and clients,com.ared to 21.9%when m.bility of clients was ***,the overall epidem.c drivers rem.ined sim.lar,with risky behavior in the general population dom.nating transm.ssion in highprevalence *** m.deling suggests that co-location of high-risk populations and generalized epidem.cs can further am.lify the spread of HIV,but that large num.ers of form.l FSW and clients are not required to observe or m.chanistically explain high HIV prevalence in the general population.

关键词： prevalence client stratified

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

m.them.tical m.deling of the biphasic dopam.nergic response to glucose

引用

Journal of Biom.dical Science and Engineering 2011年第2期4卷 136-145页

作者： m.tthias Chung britta Gobel Achim.Peters Kerstin m.Oltm.nns Andreas m.ser Departm.nt of m.them.tics Texas State UniversitySan MarcosUSA Institute of m.them.tics and Im.ge Com.uting Graduate School for Computing in Medicine and Life SciencesUniversity of LubeckLubeckGermany m.dical Clinic I University of LubeckLubeckGermany Departm.nt of Psychiatry and Psychotherapy University of LubeckLubeckGermany Departm.nt of Neurology University of LubeckLubeckGermany

In this work, we specify potential elem.nts of the brain to sense and regulate the energy m.tabolism.of the organism. Our num.rical investigations base on neurochem.cal experim.nts dem.nstrating a biphasic association between brain glucose level and neuronal activity. The dynam.cs of high and low affine KATP channels are m.st likely to play a decisive role in neuronal activity. We develop a coupled Hodgkin-Huxley m.del describing the interactive behavior of inhibitory GABAergic and excitatory dopam.nergic neurons projecting into the caudate nucleus. The novelty in our approach is that we include the synaptic coupling of GABAergic and dopam.nergic neurons as well as the interaction of high and low affine KATP channels. Both are crucial m.chanism. described by kinetic m.dels. Sim.lations dem.nstrate that our new m.del is coherent with neurochem.cal in vitro experim.nts. Even experim.ntal interventions with glibenclam.de and glucosam.ne are reproduced by our new m.del. Our results show that the considered dynam.cs of high and low affine KATP channels m.y be a driving force in energy sensing and global regulation of the energy m.tabolism. which supports central aspects of the new Selfish Brain Theory. m.reover, our sim.lations suggest that firing frequencies and patterns of GABAergic and dopam.nergic neurons are correlated to their neurochem.cal outflow.

关键词： Neuronal m.del Coupled Neurons Dopam.ne GABA K-ATP Channels Biphasic Glibenclam.de Glucosam.ne

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Size and tim. dependent internalization of label-free nano-graphene oxide in hum.n m.crophages

引用

Nano Research 2017年第6期10卷 1980-1995页

作者： Rafael G. m.ndes Angelo m.ndarino britta Koch Anne K. m.yer Alicja Bachm.tiuk Cordula Hirsch Thom.s Gem.ing Oliver G. Schm.dt Zhongfan Liu m.rk H. Rum.eli College of Physics Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou 215006 China IFW Dresden Institute for Solid State and Materials Research P.O. Box D-01171 Dresden Germany Centre of Polym.r and Carbon m.terials Polish Academy of Sciences M. Curie-Sklodowskiej 34 Zabrze 41-819 Poland Em.A - Swiss Federal Laboratories for m.terials Science and Technology Lerchenfeldstrasse 5 9014 St. Gallen Switzerland m.terial System. for Nanoelectronics Chemnitz University of Technology Reichenhainer Sir. 70 09107 Chemnitz Germany ing National Laboratory for m.lecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

Graphene oxide shows great prom.se as a m.terial for biom.dical applications, e.g., as a m.lti-drug delivery platform. With this in view, reports of studies on the interaction between nanosized graphene oxide flakes and biological cells are beginning to em.rge. However, the num.er of studies rem.ins lim.ted, and m.st used labeled graphene oxide sam.les to track the m.terial upon endocytosis. Unfortunately, the labeling process alters the surface functionality of the graphene oxide, and this additional funcfionalization has been shown to alter the cellular response. Hence, in this work we used label-free graphene oxide. We carefully tracked the uptake of three different nanoscale graphene oxide flake size distributions using scanning/transm.ssion electron m.croscopy. Uptake was investigated in undifferentiated hum.n m.nocyte cells （THP-1） and differentiated m.crophage cells. The data show clear size dependence for uptake, such that larger graphene oxide flakes （and clusters） are m.re easily taken up by the cells com.ared to sm.ller flakes. m.reover, uptake is shown to occur very rapidly, within two m.n of incubation with THP-1 cells. The data highlights a crucial need for cellular incubation studies with nanoparticles, to be conducted for short incubation periods as certain dependencies （e.g., size and concentration） are lost with longer incubation periods.

关键词： graphene oxide THP-1 cells label-free uptake size dependence

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Groundwater Geochem.stry 2005

引用

2005年

作者： Broder J. m.rkel britta Planer-Friedrich Darrell K. Nordstrom

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Highly efficient THz four-wave m.xing in doped silicon

引用

Light(Science & Applications) 2021年第5期10卷 806-811页

作者： Nils Dessm.nn Nguyen H.Le Viktoria Eless Steven Chick Kam.ar Saeedi Alberto Perez-Delgado Sergey G.Pavlov Alexander F.G.van der m.er Konstantin L.Litvinenko Ian Galbraith Nikolay V.Abrosim.v Helge Riem.nn Carl R.Pidgeon Gabriel Aeppli britta Redlich Benedict N.m.rdin Radboud University Institute for Molecules and MaterialsHFML-FELIXNijmegenThe Netherlands Advanced Technology Institute and Departm.nt of Physics University of SurreyGuildford GU27XHUK Institute of Optical Sensor System. German Aerospace CenterBerinGermany Institute of Photonics and Quantum.Sciences SUPAHeriot-Watt UniversityEdinburghUK Leibniz-Institut fur Kristallzuchtung(IKZ) BerlinGermany Laboratory for Solid State Physics ETH Zurich8093 ZurichSwitzerland Institut de Physique EPFL1015 LausanneSwitzerland Paul Scherrer Institute 5232 VlligenSwitzerland

Third-order non-linearities are im.ortant because they allow control over light pulses in ubiquitous high-quality centro-sym.etric m.terials like silicon and *** four-wave m.xing provides a direct m.asure of the third-order non-linear sheet susceptibility x^(3)(where L represents the m.terial thickness)as well as technological possibilities such as optically gated detection and em.ssion of *** picosecond pulses from.a free electron laser,we show that silicon doped with P or Bi has a value of x^(3)Lin the THz dom.in that is higher than that reported for any other m.terial in any wavelength *** im.ediate im.lication of our results is the efficient generation of intense coherent THz light via upconversion(also a x^(3)process),and they open the door to exploitation of nondegenerate m.xing and optical nonlinearities beyond the perturbative regim..

关键词： m.xing wave Highly

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：