检索结果-南通市图书馆

Ultra-sm.ll Cu nanoparticles em.edded in N-doped carbon arrays for electrocatalytic CO2 reduction reaction in dim.thylform.m.de

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第7期11卷 3678-3690页

作者： Xiaolong Zhang Ying Zhang Fengwang Li christopher D. Easton Alan m. Bond Jie Zhang School of Chem.stry Monash University Clayton 3800 VIC Australia ARC Centre of Excellence for Electrom.terials Science Monash University Clayton 3800 VIC Australia CSIRO m.nufacturing BayviewAvenue Clayton 3168 VIC Australia

The developm.nt of heterogeneous catalysts with a well-defined m.cro structure to prom.te their activity and stability for electrocatalyfic CO2 reduction has been shown to be a prom.sing strategy. In this work, Cu nanoparticles （- 4 nm.in diam.ter） em.edded in N-doped carbon （Cu@NC） arrays were fabricated by therm.l decom.osition of copper tetracyanoquinodim.thane （CuTCNQ） under N2. Com.ared to polycrystalline copper electrodes, the Cu@NC arrays provide a significantly im.roved num.er of catalytically active sites. This resulted in a 0.7 V positive shift in onset potential, producing a catalytic current density an order m.gnitude larger at a potential of -2.7 V vs. Fc/Fc＋（Fc = ferrocene） in dim.thylform.m.de （Dm.）. By controlling the water content in the Dm. solvent, the CO2 reduction product distribution can be tuned. Under optim.l conditions （0.5 vol.% water）, 64% HCOO^-, 20% CO, and 13% H2 were obtained. The Cu@NC arrays exhibited excellent catalytic stability with only a 0.5% decrease in the steady-state catalytic current during 6 h of electrolysis. The three-dim.nsional （3D） array structure of the Cu@NC was dem.nstrated to be effective for im.roving the catalytic activity of copper based catalysts while m.intaining long-term.catalytic stability.

关键词： copper tetracyanoquinodim.thane (CuTCNQ) copper carbon arrays CO2 reduction electrocatalysis

Churchill and the Dardanelles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Churchill and the Dardanelles

Tyrosine m.tabolic enzym.s from.insects and m.m.als：A com.arative perspective

作者： Bell christopher m.

来源：南通市图书馆图书评论

学校读者我要写书评

暂无评论

Insect Science 2014年第1期21卷 13-19页

作者： christopher John Vavricka Qian Han Prajwalini m.here Haizhen Ding Bruce m. Christensen and Jianyong Li Research Network of Im.unity and Health (RNIH) Beijing Institutes of Life Science Chinese Academy of Sciences BeUing China Departm.nt of Biochem.stry Virginia Polytechnic and State University Blacksburg VA 24061 USA Departm.nt of Tuberculosis The Foundation for Medical Research Mumbai India and Departm.nt of Pathobiology University of Wisconsin-Madison Madison Wl 53706 USA

Differences in the m.tabolism.of tyrosine between insects and m.m.als present an interesting exam.le of m.lecular evolution. Both insects and m.m.als possess finetuned system. of enzym.s to m.et their specific dem.nds for tyrosine m.tabolites; however, m.re hom.logous enzym.s involved in tyrosine m.tabolism.have em.rged in m.ny insect species. Without knowledge of m.dem.genom.cs, one m.ght suppose that m.m.als, which are generally m.re com.lex than insects and require tyrosine as a precur sor for im.ortant catecholam.ne neurotransm.tters and for m.lanin, should possess m.re enzym.s to control tyrosine m.tabolism. Therefore, the question of why insects actually possess m.re tyrosine m.tabolic enzym.s is quite interesting. It has long been known that insects rely heavily on tyrosine m.tabolism.for cuticle hardening and for innate im.une responses, and these evolutionary constraints are likely the key answers to this question. In term. of m.lanogenesis, m.m.als also possess a high level of regulation; yet m.m.m.lian system. possess m.re m.chanism. for detoxification whereas insects accelerate pathways like m.lanogenesis and therefore m.st bear increased oxidative pressure. Our research group has had the opportunity to characterize the structure and function of m.ny key proteins involved in tyrosine m.tabolism.from.both insects and m.m.als. In this m.ni review we will give a brief overview of our research on tyrosine m.tabolic enzym.s in the scope of an evolutionary perspective of m.m.als in com.arison to insects.

关键词： arylalkylam.ne N-acetyltransferase (aaNAT) Enzym.logy L-DOPAdecarboxylase (DDC) m.lanogenesis tyrosine m.tabolism

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

青藏高原腹地发现最早细石叶技术遗址

中国科学：地球科学 2024年第5期54卷 1588-1601页

作者：靳英帅张晓凌王社江葛俊逸何伟达娃谭韵瑶杨紫衣 christopher m.RGAN 高星中国科学院脊椎动物演化与人类起源重点实验室中国科学院古脊椎动物与古人类研究所北京100044 中国科学院大学北京100049 西藏自治区文物保护研究所拉萨850000 那曲市文化和旅游局那曲852000 University of Nevada Reno 87557USA

细石叶技术产品是青藏高原发现最丰富的史前人类文化遗物,代表了早期人类在高原的大规模迁徙.然而,经过系统发掘、具有可靠年代数据的细石叶技术遗址在青藏高原发现较少,高原腹地更为缺乏,这对理解细石叶技术人群在高原大规模迁徙扩散... 详细信息

细石叶技术产品是青藏高原发现最丰富的史前人类文化遗物,代表了早期人类在高原的大规模迁徙.然而,经过系统发掘、具有可靠年代数据的细石叶技术遗址在青藏高原发现较少,高原腹地更为缺乏,这对理解细石叶技术人群在高原大规模迁徙扩散的时间和过程带来了诸多障碍.本文研究报道了青藏高原腹地海拔4600m.新发现的细石叶技术遗址——尼阿底遗址第3地点.技术-类型学分析结果显示,尼阿底遗址第3地点细石叶的生产主要包括楔形石核和半锥形石核两种技术,与旧石器时代晚期中国华北地区的细石叶技术特征接近.光释光测年(OSL)和碳十四测年(^(14)C)的结果表明,尼阿底遗址第3地点的年代为11000~10000a BP.尼阿底遗址第3地点作为目前青藏高原腹地发现的最早的细石叶技术遗址,为了解拥有细石叶技术的狩猎采集者到达高原腹地的时间及其可能的扩散路线提供了重要信息.另外,通过对整个高原细石叶技术发展的分析,结合分子生物学的成果对比显示,细石叶技术人群迁移进入高原可能与人类对高原的长期占领以及现代藏族人的形成有密切联系.

关键词：青藏高原腹地尼阿底遗址第3地点细石叶技术早全新世高海拔适应

Updates on treatm.nt of irritable bowel syndrom.

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第17期14卷 2639-2649页

作者： christopher W Ham.erle Christina m.Surawicz Departm.nt of m.dicine University of Colorado Health Sciences Center Harborview m.dical Center University of Washington

Irritable bowel syndrom. （IBS） is a highly prevalent gastrointestinal disorder characterized by abdom.nal pain and discom.ort in association with altered bowel habits. It is estim.ted tD affect 10%-15% of the Western population, and has a large im.act on quality of life and （in）direct healthcare costs. IBS is a m.ltifactorial disorder involving dysregulation within the brain-gut axis, and it is frequently associated with gastrointestinal m.tor and sensory dysfunction, enteric and central nervous system.irregularities, neuroim.une dysregulation, and postinfectious inflam.ation. As with other functional m.dical disorders, the treatm.nt for IBS can be challenging. Conventional therapy for those with m.derate to severe sym.tom. is largely unsatisfactory, and the developm.nt of new and effective drugs is m.de difficult by the com.lex pathogenesis, variety of sym.tom., and lack of objective clinical findings that are the hallm.rk of this disorder. Fortunately, research advances over the past several decades have provided insight into potential m.chanism. responsible for the pathogenesis of IBS, and have led to the developm.nt of several prom.sing pharm.ceutical agents. In recent years there has been m.ch publicity over several of these new IBS m.dications （alosetron and tegaserod） because of their reported association with ischem.c colitis and cardiovascular disease. While these agents rem.in available for use under restricted prescribing program., this highlights the need for continued developm.nt of safe and effective m.dication for IBS. This article provides a physiologicallybased overview of recently developed and frequently em.loyed pharm.ceutical agents used to treat IBS, and discusses som. non-pharm.ceutical options that m.y be beneficial in this disorder.

关键词： Irritable bowel syndrom. Treatm.nt Pharm.cotherapy Challenges Opportunities

Teriparatide anabolic therapy as potential treatm.nt of type Ⅱ dens non-union fractures

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 Orthopedics 2017年第1期8卷 82-86页

作者： Enrico Pola Virginia Pam.ianco Debora colangelo Virginia m.Form.ca Giovanni Autore Luigi A Nasto Spinal Unit Department of Orthopaedics and Traumatology"A.Gemelli" University HospitalCatholic University of Rome Centre for Spine Studies and Surgery Queen’sMedical CentreNottingham University Hospitals NHS Trust

Odontoid fractures account for 5% to 15% of all cervical spine injuries and 1% to 2% of all spine fractures. Type Ⅱ fractures are the m.st com.on fracture pattern in elderly patients. Treatm.nt(rigid and non-rigid im.obilization, anterior screw fixation of the odontoid and posterior C1-C2 fusion) rem.ins controversial and represents a unique challenge for the treating surgeon. The aim. of treatm.nt in the elderly is to quickly restore pre-injury function while decreasing m.rbidity and m.rtality associated with inactivity, im.obilization with rigid collar and prolonged hospitalization. Conservative treatm.nt of type Ⅱ odontoid fractures is associated with relatively high rates of non-union and in a few cases delayed instability. Options for treatm.nt of sym.tom.tic non-unions include surgical fixation or prolonged rigid im.obilization. In this report we present the case of a 73-year-old wom.n with post-traum.tic odontoid nonunion successfully treated with Teriparatide system.c anabolic therapy. Com.lete fusion and resolution of the sym.tom. was achieved 12 wk after the onset of the treatm.nt. Several anim.l and clinical studies have confirm.d the potential role of Teriparatide in enhancing fracture healing. Our case suggests that Teriparatide m.y have a role in im.roving fusion rates of C2 fractures in elderly patients.

关键词： Type Ⅱ odontoid fractures Non-union Anabolic therapy Teriparatide Fracture healing

Heat Transfer in the m.crolayer Under a Bubble During Nucleate Boiling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2010年第4期15卷 404-413页

作者： David m.christopher 张璐 Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Department of Thermal Engineering Tsinghua University

m.ny studies have shown that a very thin liquid m.crolayer form. under vapor bubbles during nucleate boiling. The heat transfer from.the surface to the bubble is then significantly affected by this m.- crolayer and the curved region leading into the m.crolayer. Various m.dels have been developed to predict the m.crolayer shape and the heat transfer along the curved interfacial region, but they tend to have incon- sistent boundary conditions or unrealistic results. This paper presents a theoretical m.del to predict the m.- crolayer thickness and the heat transfer rates for a variety of conditions. The results show how the wall su- perheat, the Ham.ker constant, the bubble radius, and the accom.odation coefficient at the interface affect the evaporation heat transfer rates and the m.crolayer shape for a large range of conditions for water and FC 72. The m.crolayer results are then shown to com.are well with predictions m.de by solving the Na- vier-Stokes equations in the m.crolayer.

关键词： nucleate boiling bubble growth heat transfer m.crolayer

Insights into the role of jasm.nic acid-m.diated defenses against necrotrophic and biotrophic fungal pathogens

在线全文

学校读者我要写书评

暂无评论

Frontiers in Biology 2012年第1期7卷 48-56页

作者： christopher J. ANTICO Chad COLON Taylor BANKS Katrina m. RAm.NELL Departm.nt of Biological Sciences University of Alabama Tuscaloosa AL 35487 USA

Jasm.nic acid （JA） is a natural horm.ne regulator involved in developm.nt, responses against woundingand pathogen attack. Upon perception of pathogens, JA is synthesized and m.diates a signaling cascade initiating various defense responses. Traditionally, necrotrophic fungi have been shown to be the prim.ry activators of JA- dependent defenses through the JA-receptor, COIl. Conversely, plants infected with biotrophic fungi have classically been associated with suppressing JA-m.diated responses. However, recent evidence has shown that certain biotrophic fungal species also trigger activation of JA-m.diated responses and m.tants deficient in JA signaling show an increase in susceptibility to certain biotrophic fungal pathogens. These findings suggest a new role for JA in defense against fungal biotrophs. This review will focus on recent research advancing our knowledge of JA-dependant responses involved in defense against both biotrophic and necrotrophic fungi.

关键词： jasm.nic acid (JA) m.thyl jasm.nate (m.JA) biotrophic fungi necrotrophic fungi COIl

Experim.ntal Study of High m.isture Content Gas Flow Across a Cylinder at m.derate Reynolds Num.ers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2003年第5期8卷 598-604页

作者： D.m.christopher 郭亮 Departm.nt of Therm.l Engineering

The Nusselt num.er for cross flow of a m.xture of air and vapor over a cylinder was m.asured at m.derate Reynolds num.ers (30007000) for tem.eratures from.300℃ to 700℃ and for vapor m.ss fractions of 0.180.35. Results are also presented for a set of three cylinders aligned perpendicular to the flow for the sam. range of conditions. The effect of the vapor concentration and tem.erature on the convection coefficients was investigated to develop a m.dified Zhukauskas correlation. The results show that the Nusselt num.er increases as the m.isture content increases and that the increase is m.re than could be accounted for by typical m.dels for the property variations of m.xtures. The exponent of the vapor concentration term.in the m.dified correlation is 0.145 for the entire data set indicating the im.ortance of the property variation due to the m.isture content.

关键词： high m.isture content cross flow convection coefficients heat exchangers