检索结果-南通市图书馆

Bone morphogenetic protein-4 affects both trophobl.st and non-trophobl.st l.neage-associated gene expression in human embryonic stem cel.s

引用

Stem Cel. Discovery 2012年第4期2卷 163-175页

作者： Margaret l. Shirl.y Al.son Venabl. Raj R. Rao Nol.n l. Boyd steven l. Stice David Puett Prema Narayan Cardiovascul.r Innovation Institute University of Louisville Louisville USA Department of Biochemistry and Mol.cul.r Biol.gy University of Georgia Athens USA Department of Chemical.and l.fe Science Engineering School of Engineering Virginia Commonwealth University Richmond USA Department of Physiol.gy Southern Illinois University School of Medicine Carbondale USA

Human embryonic stem cel.s (hESC) can be induced to differentiate to trophobl.st by bone morphogenetic proteins (BMPs) and by aggregation to form embryoid bodies (EB), but there are many differences and controversies regarding the nature of the differentiated cel.s. Our goal. herein were to determine if BG02 cel.s form trophobl.st-l.ke cel.s (a) in the presence of BMP4-pl.s-basic fibrobl.st growth factor (FGF-2) and (b) upon EB formation, and (c) whether the BMP4 antagonist noggin el.cits direct effects on gene expression and hormone production in the cel.s. Transcriptome profil.ng of hESC incubated with BMP4/FGF-2 showed a down-regul.tion of pl.ripotency-associated genes, an up-regul.tion of trophobl.st-associated genes, and either a down-regul.tion or no change in gene expression for many markers of the three embryonic germ l.yers. Yet, there was up-regul.tion of several.genes associated with mesoderm, ectoderm, and endoderm, strongl. suggesting that differentiation to trophobl.st-l.ke cel.s under the conditions used does not yiel. a homogeneous cel. type. Several.genes, heretofore unreported, were identified that are al.ered in hESC in response to BMP4-mediated differentiation. The production of human chorionic gonadotropin (hCG), progesterone, and estradiol.in the differentiated cel.s confirmed that trophobl.st-l.ke cel.s were obtained. Gene expression by EB was characterized by an up-regul.tion of a number of genes associated with trophobl.st, ectoderm, endoderm, and mesoderm, and the production of hCG and progesterone confirmed that trophobl.st-l.ke cel.s were formed. These resul.s suggest that, in the presence of FGF-2, BG02 cel.s respond to BMP4 to yiel. trophobl.st-l.ke cel.s, which are al.o obtained upon EB formation. Thus, BMP4-mediated differentiation of hESC represents a viabl. cel. system for studying earl. devel.pmental.events post-impl.ntation;however, up-regul.tion of non-trophobl.st genes suggests a somewhat diverse response to BMP4/FGF-2. Noggin a

关键词： Human Embryonic Stem Cel.s Trophobl.sts Bone Morphogenetic Protein-4 Embryoid Bodies Noggin

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

Chinese Ageing in Minority Cul.ures： The Rol. of Social.Functioning

引用

Fudan Journal.of the Humanities and Social.Sciences 2011年第1期4卷 88-107页

作者： Chen Hong--l.n steven M. Shardl.w Tina l. Rochel.e

The increasing proportions of ol.er peopl. in the popul.tions of many societies and the patterns of increasing gl.bal.mobil.ty make social.services with ageing ethnic minorities of ever greater importance to social.work practitioners. The paper reviews current knowl.dge and understanding of factors that contribute to social.functioning within and outside the famil. among one migrant group： ol.er ethnic Chinese in Western countries. The findings show that the capacity to maintain a functional.social.rol. varies across different groups of Chinese ethnic el.ers： some are marginal.zed and excl.ded from mainstream social.engagement on a number of different l.vel.. Some have difl.icul.y in accessing publ.c services; some are in a disadvantageous position with regard to wider social.connections; and others are empowered in l.ter l.fe in terms of income, social.engagement, autonomy and being in a col.ective, reciprocal.rel.tionship. The impact of these factors is compl.cated by the mixture of the ol.er peopl.＇s cul.ural.heritage, degree of accul.uration, socioeconomic status, educational.achievements, patterns and history of immigration, refigious bel.efs, and famil. dynamics. Simil.rl. these factors must be understood by social.service professional. for providing services to match the needs of ethnic Chinese ol.er peopl..

关键词： ageing Chinese ethnic minorities social.functioning

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

Pharmacol.gic inhibition of mTORC1 mimics dietary protein restriction in a mouse model.of l.ctation

引用

Journal.of Animal.Science and Biotechnol.gy 2021年第2期12卷 729-738页

作者： Virginia l.Pszczol.owski steven J.Hal.erson Emma J.Meyer Amy l.n Sebastian I.Arriol. Apel. Department of Animal.and Dairy Sciences University of Wisconsin-MadisonMadisonWIUSA Endocrinol.gy and Reproductive Physiol.gy Graduate Training Program University of Wisconsin-MadisonMadisonWIUSA

Background:Understanding the mechanisms of N util.zation for l.ctation can l.ad to improved requirement estimates and increased efficiency,which modern dairy diets currentl. fail.to *** mechanistic target of rapamycin compl.x 1(mTORC1)is a central.hub of transl.tion regul.tion,processing extra-and intra-cel.ul.r signal. of nutrient avail.bil.ty and physiol.gical.state,such as amino acids and *** hypothesized that dietary amino acids regul.te l.ctation through mTORC1,such that inhibition of mTORC1 wil. l.ad to decreased l.ctation performance when amino acids are not *** objectives were to assess l.ctation performance in l.ctating mice undergoing dietary and pharmacol.gic interventions designed to al.er mTORC1 ***:First l.ctation mice(N=18;n=6/treatment)were fed an adequate protein diet(18%crude protein),or an isocal.ric protein-restricted diet(9%crude protein)from the day after parturition until.l.ctation day 13.A third group of mice was fed an adequate protein diet and treated with the mTORC1 inhibitor rapamycin(4 mg/kg every other day)intraperitoneal.y,with the first two groups treated with vehicl. as *** and pups were weighed dail.,and feed intake was recorded every other *** production was measured every other day beginning on l.ctation day 4 by the weigh-suckl.-weigh *** were col.ected after fasting and ***:Mil. production and pup weight were simil.rl. decreased by both protein restriction and rapamycin treatment,with final.production at 50%of control.P=0.008)and final.pup weight at 85%of control.Pl.tion of mTORC1’s downstream targets were decreased by protein restriction and rapamycin treatment(Pl. very l.ttl. effect was observed in the l.ver of rapamycin treated mice,and none by protein ***:Overal.,sufficient suppl. of dietary amino acids was unabl. to maintain l.ctation performance status in mice with pharmacol.gical.y reduced mam

关键词： Amino acids l.ctation Mammary Mouse model mTORC1 Rapamycin

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

Compact and robust supercontinuum generation and post-compression using mul.ipl. thin pl.tes

引用

High Power l.ser Science and Engineering 2021年第4期9卷 234-241页

作者： Xinhua Xie Yunpei Deng steven l.Johnson Swiss FEl Paul Scherrer Institute5232 Villi genSwitzerland Institute for Quantum El.ctronics Physics DepartmentETH ZurichETH Zurich8093 ZurichSwitzerland

We report on compact and robust supercontinuum generation and post-compression using transmission of l.ght through mul.ipl. thin sol.d pl.tes at the Swiss FEl.X-ray free-el.ctron l.ser facil.ty.A singl. stage consisting of three thin pl.tes fol.owed by a chirped mirror compressor achieves compression of initial.y 30-fs pul.es with 800-nm center wavel.ngth to sub-10-fs *** al.o demonstrate a two-stage impl.mentation to compress the pul.es further to sub-5-fs *** the two-stage setup,the generated supercontinuum incl.des wavel.ngths ranging from 500 to 1100 *** mul.ipl.te setup is compact,robust,and stabl.,which makes it ideal.for appl.cations at free-el.ctron l.ser facil.ties such as pump-probe experiments and l.ser-arrival.timing tool..

关键词： post-compression sel.-phase modul.tion supercontinuum generation

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

Inferring the Structure of the Pre-Protostel.ar Core l.498

引用

International.Journal.of Astronomy and Astrophysics 2014年第3期4卷 519-529页

作者： Sandra l. Doty steven D. Doty Matthew J. Perkett Department of Physics and Astronomy Denison University Granville USA Department of Physics Ohio University Lancaster Lancaster USA

We present a study of the pre-protostel.ar core (PPC) l.498. A series of sel.-consistent, three-dimensional.continuum radiative transfer model. are constructed. The outputs of these model. are convol.ed with appropriate tel.scope beam responses, incl.ding the effect of beam chopping to simul.te SCUBA observations. The simul.ted observations are compared with existing observational.data. An automated search is conducted in the mul.i-dimensional.parameter space to identify the best-fit model. Grids of model. are constructed in the vicinity of the best fit in order to understand the sensitivity/uncertainty of the resul.s. We find that the source is wel. fit by a prol.te spheroid of cutoff (and thus approximatel. outer) radius rcut = 0.073 ± 0.005 pc, axis ratio q = 2.0 ± 0.2, a central.l.minosity l. -3 l.un, and an optical.depth in the visibl. of τv = 20 ± 5. We find that the PPC is il.uminated by two external.radiation fiel.s: a uniform ISRF of strength sISRF= 0.5 ± 0.25 and a l.cal.pl.ne-paral.el.radiation fiel. sPPRF = 1.0 ± 0.5. Both of these radiation fiel.s are l.cal.y attenuated, with τISRF = 1.0 ± 0.25, and τPPRF = 1.25 ± 0.75, consistent with the fact that l.498 is embedded in a l.rger cl.ud. Most interestingl., the density fal.-off at the outer edge is extremel. steep, having a power l.w of m > 10. This is effectivel. a “sharp edge” to the PPC, and together with the constant density interior, is interpreted as potential.signs of a pressure-confined core.

关键词： Stars: Formation ISM: Cl.uds ISM: l.498 Submil.meter: Stars ISM: Structure Infrared: Stars

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

UNUSUAl.NANOMETER-SIZED NSUTITE FROM BASIC SYSTEMS

UNUSUAL NANOMETER-SIZED NSUTITE FROM BASIC SYSTEMS

引用

第二届中日化工学术研讨会

作者： SUIB steven l. THOMSON Mary BOWDEN Wil.iam Department of Chemistry Institute of Material. Science University of Connecticut Starrs Connecticut 06269-4060 North Atl.ntic Group Duracell Company 37 A Street Needham Massachusetts 02194-2875

Nanometer-sized manganese oxides material. are one of the focuses for scientists in this fiel. and novel.properties may be found, due to quantum confinement effects. The most widel. used cathode material. in primary al.al.ne batteries nsutite (γ-MnO2) is often described as an intergrowth of pyrol.site and ramsdel.ite tunnel.structures. Our research concerns the preparation, structures, and properties of nanometer-sized nsutite with the l.ngest diameter sizes of about 30-40 nm from basic systems, instead of traditional.nsutite synthesized in the acidic environments. Fl.t perfect crystal.surfaces of nanometer-sized nsutite characterized by FESEM show that there are pure and fewer cation vacancies et al.defects on the surface of the frameworks, further proved by IR, TG, and BET methods. CV experiment resul.s showed that the currents at -240 mV, corresponding to the homogeneous reduction from Mn4+ to Mn3+ , were twice of traditional.sampl.s from acidic environments, due to the smal. particl. size, fewer cation vacancies, and l.rger numbers of Mn4+ ions on the surfaces.

关键词： nanometer-sized nsutite basic systems defects

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Anatomy of Free Fl.p Fail.res: Dissection of a Series

引用

Modern Pl.stic Surgery 2013年第3期3卷 89-95页

作者： steven P. Davison Mark W. Cl.mens Andrew l. Kochuba Department of Pl.stic Surgery Georgetown University Hospital Washington DC USA

Introduction: Free fl.p success rates have remained stabl. in recent years ranging 93% to 98%. Historical.y, the causes of free fl.p fail.res were attributed to the surgeon’s inexperience and technique. However, there are factors beyond the surgical.anastomosis that contribute to fl.p fail.re. The purpose of this study is to review each case of total.fl.p l.ss in detail.to devel.p a better understanding of compl.cations. Methods: A retrospective study was performed over el.ven years in a singl. surgeon’s practice, a predominantl. head and neck reconstructive practice. Al. charts were independentl. reviewed. In patients who sustained total.fl.p l.ss, a review was conducted of patient comorbidites, anesthesia records, perioperative and fol.ow-up notes. Resul.s: A total.of 514 free fl.ps were performed. 76% (392) of these fl.ps were for head and neck reconstruction. There were 22 total.fl.p l.sses (4%) and 26 partial.fl.p l.sses (5%). Of the 22 total.fl.p l.sses, four fl.ps were avul.ed, five fl.ps were in patients l.ter found to have coagul.tion disorders (homozygous mutations of the MTHFR gene and factor V l.iden), four patients were exposed to neosynephrine, two patients remained hypotensive perioperativel., and four del.yed fl.p l.sses were attributed to pseudomonal.infection. Five l.sses were technical.or rel.ted to fl.p inexperience. Several.representative case scenarios are il.ustrated. Concl.sion: Careful.review of free fl.p fail.res indicates that a thorough workup (particul.rl. coagul.tion disorders), fl.p sel.ction, surgeon to anesthesia communication, proper securing of the fl.p, and postoperative patient bl.od pressure and infection control.have a greater part to pl.y in this new era of anastomotic success.

关键词： Free Fl.ps Fl.p l.ss Head and Neck Reconstruction Coagul.pathy MTHFR Factor V l.iden

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

Design Guidel.nes for Buried Profil.-Wal. Pipe

引用

Journal.of Civil.Engineering and Architecture 2012年第1期6卷 26-43页

作者： Rex P. Burgon steven l. Fol.man A. P. Moser Mechanical.and Aerospace Engineering Department Utah State University

The overal. objective of this study was to provide guidance for proper design of profil.-wal.ed pipe. Data from buried pipe tests on HDPE pipes with thirteen different profil.s were incl.ded in the study. These tests were run in the soil.cel. at Utah State University. Al.o, paral.el.pl.te tests were al.o compl.ted on the pipe sampl.s. Data from 39 buried pipe tests were anal.zed. The buried tests were at 75, 85 and 95 percent of standard Proctor density. This paper summarizes the resul.s of that study and focuses on the tests buried in 85 percent dense soil. In addition to the experimental.data, a portion of this paper focuses on finite el.ment anal.sis resul.s to confirm and extend the resul.s from the physical.tests. Design l.mits are recommended for several.dimensionl.ss parameters that describe profil. geometry. One of the significant concl.sions of this study was that pipes with profil.s that perform wel. when buried in soil.al.o perform wel. in a paral.el.pl.te tests. The identities of the pipe manufacturers are not discl.sed, and pipes are onl. described in terms of basic parameters such as cross-sectional.area and area moments of inertia.

关键词： Pipe buried profil.-wal. guidel.nes.

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

Pl.usibl. combinations: An improved method to eval.ate the covariate structure of Cormack-Jol.y-Seber mark-recapture model.

引用

Open Journal.of Ecol.gy 2013年第1期3卷 11-22页

作者： Jeffrey F. Bromaghin Trent l. McDonal. steven C. Amstrup Pol.r Bears International Bozeman USA US Geol.gical.Survey Alaska Science Center Anchorage USA Western Ecosystems Technol.gy Inc. Cheyenne USA

Mark-recapture model. are extensivel. used in quantitative popul.tion ecol.gy, providing estimates of popul.tion vital.rates, such as survival. that are difficul. to obtain using other methods. Vital.rates are commonl. model.d as functions of expl.natory covariates, adding considerabl. fl.xibil.ty to mark-recapture model., but al.o increasing the subjectivity and compl.xity of the model.ng process. Consequentl., model.sel.ction and the eval.ation of covariate structure remain critical.aspects of mark-recapture model.ng. The difficul.ies invol.ed in model.sel.ction are compounded in Cormack-Jol.y-Seber model. because they are composed of separate sub-model. for survival.and recapture probabil.ties, which are conceptual.zed independentl. even though their parameters are not statistical.y independent. The construction of model. as combinations of sub-model., together with mul.ipl. potential.covariates, can l.ad to a l.rge model.set. Al.hough desirabl., estimation of the parameters of al. model. may not be feasibl.. Strategies to search a model.space and base inference on a subset of al. model. exist and enjoy widespread use. However, even though the methods used to search a model.space can be expected to infl.ence parameter estimation, the assessment of covariate importance, and therefore the ecol.gical.interpretation of the model.ng resul.s, the performance of these strategies has received l.mited investigation. We present a new strategy for searching the space of a candidate set of Cormack-Jol.y-Seber model. and expl.re its performance rel.tive to existing strategies using computer simul.tion. The new strategy provides an improved assessment of the importance of covariates and covariate combinations used to model.survival.and recapture probabil.ties, whil. requiring onl. a modest increase in the number of model. on which inference is based in comparison to existing techniques.

关键词： Capture-Recapture Survival Model Buil.ing Model Sel.ction Model Averaging Mul.i-Model Inference Covariates Covariate Weights CJS Akaike’s Information Criterion AIC AICC

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

An investigation of the l.shel. x-ray conversion efficiency for l.ser-irradiated tin foil.

引用

Pl.sma Science and Technol.gy 2020年第4期22卷 48-54页

作者： David BAIl.E Cormac HYl.ND Raj l.SINGH steven WHITE Gianl.ca SARRI Francis P KEENAN David RIl.Y steven J ROSE Edward G HIl. Feil. WANG Dawei YUAN Gang ZHAO Huigang WEI Bo HAN Baoqiang ZHU Jianqiang ZHU Pengqian YANG Centre for Pl.sma Physics School of Mathematics and PhysicsQueen's University BelfastBelfastBT7 INNUnited Kingdom Astrophysics Research Centre School of Mathematics and PhysicsQueen's University BelfastBelfastBT7 INNUnited Kingdom Pl.sma Physics Group Blackett LaboratoryPrince Consort RoadLondonSW72AZUnited Kingdom Key l.boratory of Optical.Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012People's Republic of China Department of Astronomy Beijing Normal UniversityBeijing 100875People's Republic of China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences.Shanghai 201800People's Republic of China

We have used the ShenguangⅡl.ser in third harmonic(351 nm)to investigate the emission of l.shel. radiation in the 3.3–4.4 ke V range generated using thin foil. of Sn coated onto a paryl.ne substrate with irradiation of order 1015 W cm-2 and nanosecond pul.e *** our experiment,we have concentrated on assessing the emission on the non-l.ser irradiated side as this al.ows an experimental.geometry rel.vant to experiments on photo-ionised pl.smas where a secondary target must be pl.ced cl.se to the source,to achieve x-ray fl.xes appropriate to astrophysical.*** l.shel. conversion efficiencies are estimated to be of order 1%,with l.ttl. dependence on Sn thickness between 400 and 800 nm.

关键词： conversion efficiency l.ser pl.sma x-ray sources l.boratory astrophysics

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

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：