检索结果-南通市图书馆

Endangered species and nature conservation: science issues and challenges

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2008年第2期3卷 75-82页

作者： robert C.SZARO US Geological Survey Biological Resources DisciplineRestonVirginiaUSA

The issues and challenges facing us in ensuring the survival of as many species and ecosystems as possible call fora renewed research focus to address how to improve management strategies and policy making now and into thefuture. The key issues to be addressed by activities of the International Union of Forest Research Organization’s(IUFRO) Task Force on Endangered Species and Nature Conservation include such issues as: (i) preventing speciesfrom being listed by maintaining species populations at sufficient levels that they do not require listing;(ii) recoveringthreatened and endangered species;(iii) developing management practices and strategies;(iv) balancingactions affecting suites of threatened or endangered species;(v) developing conservation strategies for specieswithout definitive taxonomic treatments;(vi) dealing with global change;(vii) dealing with invasive species;and(viii) restoring critical habitats.

关键词： endangered species management practices nature conservation restoration science issues

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

可再生燃料的光催化和光电催化合成专栏

Chinese Journal of Catalysis 2022年第9期43卷 2271-2272页

作者：唐军旺 Lianzhou Wang robert Godin Roland Marschall Academia Europaea European Academy of Sciences Royal Society of Chemistry Materials Chemistry and Engineering University College London UK Department of Chemical Engineering University College London Nanomaterials Centre Australian Institute for Bioengineering and Nanotechnology and School of Chemical Engineering The University of Queensland Brisbane Qld 4072 Australia Department of Chemistry Irving K.Barber Faculty of Science The University of British Columbia Okanagan Campus 3247 University Way KelownaBCV1V 1V7Canada Department of Chemistry University of Bayreuth 95440 Bayreuth Germany

A renewable energy supply is an integral part of a sustainable *** most abundant and widespread renewable energy source available on the earth,i.e.,sunlight,is intermittent and has a low energy *** makes an economical and efficient technology to convert and store the solar energy necessary in order to utilise it on our path towards a low carbon *** and photo‐electrocatalysis can in principle store renewable solar energy into chemical bonds by diverse chemical processes,including water splitting to H_(2),nitrogen reduction to ammonia,CO_(2) reduction to chemicals and *** chemical processes physically involve charge generation,charge separation and transfer,chemically include two half reactions and generally share the very sluggish water oxidation half *** persistent kinetic challenges of these complex photophysical and photochemical processes have kept solar to fuel conversion efficiency as very moderate.

关键词： reaction. density. synthesis

Epididymosomes are involved in the acquisition of new sperm proteins during epididymal transit

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2007年第4期9卷 483-491页

作者： robert Sullivan Gilles Frenette Julie Girouard Centre de Recherche en Biologie de la Reproduction and Departement d＇Obstetrique-Gynecologie Faculte de Medeeine Universite Laval Quebec G1 V 4G2 Canada

During epididymal transit, spermatozoa acquire new proteins. Some of these newly acquired proteins behave as integral membrane proteins, including glycosylphosphatidylinositol （GPI）-anchored proteins. This suggests that the secreted epididymal proteins are transferred to spermatozoa by an unusual mechanism. Within the epididymal lumen, spermatozoa interact with small membranous vesicles named epididymosomes. Many proteins are associated with epididymosomes and the protein composition of these vesicles varies along the excurrent duct and differs from soluble intraluminal proteins. Some epididymosome-associated proteins have been identified and their functions in sperm maturation hypothesized. These include P25b, a zona pellucida binding protein, macrophage migration inhibitory factor, enzymes of the polyol pathway, HE5/CD52, type 5 glutathione peroxidase, and SPAM 1 or PH-20. The electrophoretic patterns of proteins associated to epididymosomes are complex and some of these proteins are transferred to defined surface domains of epididymal spermatozoa. Epididymosomes collected from different epididymal segments interact differently with spermatozoa. This protein transfer from epididymosomes to spermatozoa is timedependent, temperature-dependent and pH-dependent, and is more efficient in the presence of zinc. Some proteins are segregated to lipid raft domains of epididymosomes and are selectively transferred to raft domains of the sperm plasma membrane. Some evidence is presented showing that epididymosomes are secreted in an apocrine manner by the epididymal epithelial cells. In conclusion, epididymosomes are small membranous vesicles secreted in an apocrine manner in the intraluminal compartment of the epididymis and play a major role in the acquisition of new proteins by the maturing spermatozoa. （Asian J Androl 2007 July; 9： 483-491）

关键词： apocrine secretion epididymis epididymosomes spermatozoa sperm maturation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

喷流对飞机尾流涡影响的试验研究

航空学报 2010年第5期31卷 899-908页

作者：黄烁桥申功忻 robert Konrath Carl F.v. Carmer Kompenhans Jurgen 北京航空航天大学航空科学与工程学院北京100191 德国宇航院气动与流动技术研究所哥廷根37073

飞机产生的尾流涡,特别是大尺度的翼尖涡,对尾随其后的飞行器是非常有害的,本文旨在探索利用飞机发动机产生的喷流加速尾流涡消亡的方法。试验采用简化的飞机模型(有尾翼),建立了包含一对翼尖涡及一对反向旋转的尾翼涡(通过以负迎角安... 详细信息

飞机产生的尾流涡,特别是大尺度的翼尖涡,对尾随其后的飞行器是非常有害的,本文旨在探索利用飞机发动机产生的喷流加速尾流涡消亡的方法。试验采用简化的飞机模型(有尾翼),建立了包含一对翼尖涡及一对反向旋转的尾翼涡(通过以负迎角安装尾翼得到)的4涡尾流系统。在无外来扰动的情况下,不同的尾翼设置下得到的尾翼涡对翼尖涡的作用效果不同,有的能导致翼尖涡提前消亡,有的则不能。考察了不同强度的喷流对不同4涡尾流系统的影响,且作为对比,对无尾翼(2涡系统)及无喷流下的各种情况也分别作了观测。试验在拖曳水槽中进行,运用体视粒子图像测速(SPIv)技术,观测了与模型拖曳方向垂直的、从机翼后缘到下游约45翼展间均布的一系列切面。结果表明:当喷流直接作用于涡时,其效果主要取决于两者之间的初始距离及相对强度;而当喷流作用于整个4涡尾流系统时,其引入的扰动对不同的系统均能起到一定程度的改善作用,这种作用的关键在于利用喷流优化对翼尖涡进行扰动的机制,而不仅仅取决于喷流的强度。

关键词：流体力学飞机尾流喷流体视粒子图像测速

Persistence of Healthcare-Associated (Nosocomial) Infections Due to Inadequate Hand Hygiene: Part 1—Biological and Treatment Factors

在线全文

学校读者我要写书评

暂无评论

Pharmacology & Pharmacy 2018年第8期9卷 293-309页

作者： robert B. Raffa Joseph v. Pergolizzi robert Taylor Sanjib Choudhuri robert Rodenbeck University of Arizona College of Pharmacy Tucson AZ USA Professor Emeritus Temple University School of Pharmacy Philadelphia PA USA Neumentum Inc. Palo Alto CA USA NEMA Research Inc. Naples FL USA Delta Faucet Co. Indianapolis IN USA

The most frequent adverse event in the healthcare delivery system is acquisition of an infection within a healthcare facility. Since infection control measures are known, simple, and low-cost, we examine why the problem of healthcare-associated infections persists. Hundreds of millions of patients each year are affected by a healthcare-associated infection, with negative medical outcome and financial cost. It is a major public health problem even in countries with advanced healthcare systems. This is a bit perplexing, given that hygienic practices have been known and actively promoted. The objective is to address the question: doesn’t the use of disinfection, sterilization, handwashing, and alcohol rubs prevent the spread of pathogenic organisms? We conclude that the persistent high prevalence of nosocomial infections despite known hygienic practices is attributable to two categories of factors: biological and inherent shortcomings of some practices (considered in Part 1), and human factors (considered in Part 2). A new approach is presented in Part 3.

关键词： Infection Nosocomial Hospital Healthcare-Associated Hygiene Handwashing

Kernel Density Estimation of Tropical Cyclone Frequencies in the North Atlantic Basin

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Geosciences 2010年第3期1卷 121-129页

作者： Timothy A. Joyner robert v. Rohli 不详

Previous research has identified specific areas of frequent tropical cyclone activity in the North Atlantic basin. This study examines long-term and decadal spatio-temporal patterns of Atlantic tropical cyclone frequencies from 1944 to 2009, and analyzes categorical and decadal centroid patterns using kernel density estimation (KDE) and centrographic statistics. Results corroborate previous research which has suggested that the Bermuda-Azores anticyclone plays an integral role in the direction of tropical cyclone tracks. Other teleconnections such as the North Atlantic Oscillation (NAO) may also have an impact on tropical cyclone tracks, but at a different temporal resolution. Results expand on existing knowledge of the spatial trends of tropical cyclones based on storm category and time through the use of spatial statistics. Overall, location of peak frequency varies by tropical cyclone category, with stronger storms being more concentrated in narrow regions of the southern Caribbean Sea and Gulf of Mexico, while weaker storms occur in a much larger area that encompasses much of the Caribbean Sea, Gulf of Mexico, and Atlantic Ocean off of the east coast of the United States. Additionally, the decadal centroids of tropical cyclone tracks have oscillated over a large area of the Atlantic Ocean for much of recorded history. Data collected since 1944 can be analyzed confidently to reveal these patterns.

关键词： Atlantic Tropical Cyclone Frequencies Decadal Centroid Patterns Kernel Density Estimation (KDE) Centrographic Statistics Bermuda-Azores Anticyclone Teleconnections

Galectin-1-mediated biochemical controls of melanoma and glioma aggressive behavior

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 Biological Chemistry 2011年第9期2卷 193-201页

作者： Florence Lefranc véronique Mathieu robert Kiss Laboratory of Toxicology Faculty of PharmacyUniversité Libre de Bruxelles Department of Neurosurgery Erasme Academic Hospital

Gliomas and melanomas are associated with dismal prognosis because of their marked intrinsic resistance to proapoptotic stimuli,such as conventional chemotherapy and radiotherapy,as well as their ability to escape immune cell *** addition,gliomas and melanomas display pronounced ***-1 is a hypoxia-sensitive protein,which is abundantly secreted by glioma and melanoma cells,which displays marked proangiogenic *** also provides immune tolerogenic environments to melanoma and glioma cells through the killing of activated T cells that attack these tumor ***-1 protects glioma and melanoma cells against cytotoxic insults(including chemotherapy and radiotherapy) through a direct role in the unfolded protein ***,these facts clearly point to galectin-1 as an important target to be combated in gliomas and melanomas in order to:(1) weaken the defenses of these two types of cancers against radiotherapy,chemotherapy and immunotherapy/vaccine therapy;and(2) reinforce antiangiogenic *** the present article,we review the biochemical and molecular biology-related pathways controlled by galectin-1,which are actually beneficial for melanoma and glioma cells,and therefore detrimental for melanoma and glioma patients.

关键词： Galectin-1 Glioma Melanoma Biochemical pathways

Outcomes of central hepatectomy versus extended hepatectomy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2019年第3期18卷 249-254页

作者： Jenny Chan Luke Bradshaw Nezor Houli Laurence Weinberg Marcos v Perini Michael Fink vijayaragavan Muralidharan Graham Starkey robert Jones Bao Zhong Wang Christopher Christophi Mehrdad Nikfarjam Department of Surgery University of Melbourne Austin Health Heidelberg Melbourne Victoria Australia Department of Surgery University of Melbourne Northern Health Epping Victoria Australia Department of Anaesthesia University of Melbourne Austin Health Heidelberg Melbourne Victoria Australia

Background: Central hepatectomy(CH) is more difficult than extended hepatectomy(EH) and is associated with greater morbidity. In this modern era of liver management with aims to prevent posthepatectomy liver failure(PHLF), there is a need to assess outcomes of CH as a parenchyma-sparing procedure for centrally located liver tumors. Methods: A total of 178 major liver resections performed by specialist surgeons from two Australian tertiary institutions between June 2009 and March 2017 were reviewed. Eleven patients had CH and 24 had EH over this study period. Indications and perioperative outcomes were compared between the groups. Results: The main indication for performing CH was colorectal liver metastases. There was no perioperative mortality in the CH group and four(16.7%) in the EH group( P = 0.285). No group differences were found in median operative time [CH vs. EH: 450 min(290–840) vs. 523 min(310–860), P = 0.328], intraoperative blood loss [850 mL(40 0–150 0) vs. 650 mL(10 0–20 0 0), P = 0.746] or patients requiring intraoperative blood transfusion [1(9.1%) vs. 7(30.4%), P = 0.227]. There was a trend towards fewer hepatectomyspecific complications in the CH group [3(27.3%) vs. 13(54.2%), P = 0.167], including PHLF(CH vs. EH: 0 vs. 29.2%, P = 0.072). Median length of stay was similar between groups [CH vs. EH: 9 days(5–23) vs. 12 days(4–85), P = 0.244]. Conclusions: CH has equivalent postoperative outcomes to EH. There is a trend towards fewer hepatectomy-specific complications, including PHLF. In appropriate patients, CH may be considered as a safe parenchyma-sparing alternative to EH.

关键词： Central hepatectomy Mesohepatectomy Central bisectionectomy Central bisegmentectomy Extended hepatectomy

Predicting the inhibition efficiencies of magnesium dissolution modulators using sparse machine learning models

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1783-1791页

作者： Elisabeth J.Schiessler Tim Würger Sviatlana v.Lamaka robert H.Meißner Christian J.Cyron Mikhail L.Zheludkevich Christian Feiler Roland C.Aydin Institute of Material Systems Modeling Helmholtz-Zentrum HereonGeesthachtGermany Institute of Surface Science Helmholtz-Zentrum HereonGeesthachtGermany Institute of Polymers and Composites Hamburg University of TechnologyHamburgGermany Institute for Continuum and Material Mechanics Hamburg University of TechnologyHamburgGermany Institute for Materials Science Faculty of EngineeringKiel UniversityKielGermany

The degradation behaviour of magnesium and its alloys can be tuned by small organic ***,an automatic identification of effective organic additives within the vast chemical space of potential compounds needs sophisticated ***,we propose two systematic approaches of sparse feature selection for identifying molecular descriptors that are most relevant for the corrosion inhibition efficiency of chemical *** is based on the classical statistical tool of analysis of variance,the other one based on random *** demonstrate how both can—when combined with deep neural networks—help to predict the corrosion inhibition efficiencies of chemical compounds for the magnesium alloy *** particular,we demonstrate that this framework outperforms predictions relying on a random selection of molecular ***,we point out how autoencoders could be used in the future to enable even more accurate automated predictions of corrosion inhibition efficiencies.

关键词： corrosion alloy magnesium