检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

特发性左心室流出道心外膜侧室性心动过速

中华心律失常学杂志 2001年第6期5卷 339-341页

作者：王祖禄韩雅玲王守力王效增 warren m jackman 沈阳军区总医院心内科 110016 美国Oklahoma大学心电生理中心

目的报道９例经电生理检查证实的特发性左心室流出道心外膜侧室性心动过速（室速）的体表心电图及电生理检查特点。方法男性５例，女性４例，年龄１５－５８岁，６例为运动诱发的持续性室速，３例为运动诱发的非持续性室速。结果室... 详细信息

目的报道９例经电生理检查证实的特发性左心室流出道心外膜侧室性心动过速（室速）的体表心电图及电生理检查特点。方法男性５例，女性４例，年龄１５－５８岁，６例为运动诱发的持续性室速，３例为运动诱发的非持续性室速。结果室速时，９例体表心电图ＱＲＳ波全部呈现右束支阻滞图形（８例胸前导联Ｖ１－Ｖ６呈现高Ｒ波），Ⅱ、Ⅲ、ａＶＦ导联为高Ｒ波，Ｉ、ａＶＬ导联为ＱＳ波。电生理检查，右心室和左心室心内膜标测未发现最早心室激动点，在较早心室心内膜激动处的心内电图多呈现起始部低幅电位，提示远场电位。心室内起搏标测未发现与室速体表心电图１２导联ＱＲＳ波形态相同的起搏点。８例通过心脏静脉系统标测发现最早的心室激动点［体表心电图最早ＱＲＳ波前１５－５０ｍｓ，平均（３２ ± １２）ｍｓ］和完全或近乎完全的起搏标测位于心大静脉的远端１例、心前间隔静脉的近端７例。１例患者在左心室流出道消融成功，１例患者在心大静脉远端血管内消融成功。其他患者在右心室和／或左心室内消融失败。结论心脏静脉标测可以鉴别出特发性左心室流出道心外膜侧室速。

关键词：导管消融室性心动过速左心室流出道心外膜侧电生理 ILVT RVOT-VT

AC Impedance Behaviour of Black Diamond Films

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2005年第6期21卷 879-882页

作者： Olivier GAUDIN Richard B.jackman Electronic and Electrical Engineering University College London Torrington Place London WC1E 7JE UK

The first measurement of impedance on free-standing diamond films from 0.1 Hz to 10 mHz up to 300℃ were reported. A wide range of chemical vapour deposition （CVD） materials were investigated, but here we concentrate on ‘black＇ diamond grown by microwave plasma enhanced CVD （mWPECVD）. The Cole-Cole （Z′ via Z″） plots are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 mΩ at room temperature to 4 kΩ at 300℃, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 100 pF up to 300℃ suggesting that the diamond grain boundaries are dominating the conduction. At 400℃, the impedance at low frequencies shows a linear tail, which can be explained that the AC polarization of diamond/Au interface occurs.

关键词： Black diamond Impedance spectroscopy Activation energy

Population differentiation at a regional scale in spadefoot toads： contributions of distance and divergent selective environments

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2016年第2期62卷 193-206页

作者： Amber m. RICE michael A. mCQUILLAN Heidi A. SEEARS Joanna A. warren Department of Biological Sciences Lehigh University BethLehem PA 18015 USA

The causes of population differentiation can provide insight into the origins of early barriers to gene flow. Two key drivers of population differentiation are geographic distance and local adaptation to divergent selective environments. When reproductive isolation arises because some populations of a species are under selection to avoid hybridization while others are not, population differentiation and even speciation can result. Spadefoot toad populations Spea multiplicata that are sympatric with a congener have undergone reinforcement. This reinforcement has resulted not only in increased reproductive isolation from the congener, but also in the evolution of reproductive isolation from nearby and distant conspecific allopatric populations. We used multiple approaches to evaluate the contributions of geographic distance and divergent selective environments to population structure across this regional scale in S. multiplicata, based on genotypes from six nuclear microsatellite markers. We compared groups of populations varying in both geographic location and in the presence of a congener. Hierarchical F-statistics and results from cluster analyses and discriminant analyses of principal components all indicate that geographic distance is the stronger contributor to genetic differentiation among S. multiplicata populations at a regional scale. However, we found evidence that adaptation to divergent selective environments also contributes to population structure. Our findings highlight how variation in the balance of evolutionary forces acting across a species＇ range can lead to variation in the relative contributions of geographic distance and local adaptation to population differentiation across different spatial scales.

关键词： cascade reinforcement character displacement reproductive isolation spatial scale Spea multipficata speciation

Principles of Nanoparticle Delivery to Solid Tumors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical Engineering Frontiers 2023年第1期4卷 177-186页

作者： warren C.W.Chan Institute of Biomedical Engineering University of TorontoTorontoON M5S 3G9Canada.Terrence Donnelly Center for Cellular&Biomolecular ResearchUniversity of TorontoTorontoON M53E1Canada.Department of ChemistryUniversity of TorontoTorontoON M5S 3H6Canada

The effective treatment of patients with cancer hinges on the delivery of therapeutics to a tumor *** provide an essential transport *** present 5 principles to consider when designing nanoparticles for cancer targeting:(a)Nanoparticles acquire biological identity in vivo,(b)organs compete for nanoparticles in circulation,(c)nanoparticles must enter solid tumors to target tumor components,(d)nanoparticles must navigate the tumor microenvironment for cellular or organelle targeting,and(e)size,shape,surface chemistry,and other physicochemical properties of nanoparticles influence their transport process to the *** review article describes these principles and their application for engineering nanoparticle delivery systems to carry therapeutics to tumors or other disease targets.

关键词： organs cancer carry

Implications of a new, biostratigraphically well-controlled, radio-isotopic age for the lower Telychian Stage of the Llandovery Series （Lower Silurian, Sweden）

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Episodes 2008年第3期31卷 309-314页

作者： Stig m. Bergstrom Funda Ozlem Toprak warren D. Huff Roland mundil School of Earth Sciences Division of Geological Sciences The Ohio State University 155 S. Oval Mall Columbus Ohio 43210 USA. Department of Geoiogy University of Cincinnati Cincinnati Ohio 45221 USA Berkeley Geochronology Center 2455 Ridge Road Berkeley California 94709 USA.

Radio-isotopic analysis of single zircons from two early Telychian K-bentonites, one of which is among the most widespread Lower Paleozoic volcanic ash falls in north- ern Europe, yields overlapping weighted mean 206pb/238U ages of 438. 7± 1.0 ma and 437.8 ± 0.5 ma, respectively. The former age is from zircons of the Osmundsberg K-bentonite from the type locality at Osmundsberget in the Siljan area of central Sweden where it occurs in the lower part of the Spirograptus tur- riculatus Graptolite Zone and in the lower part of the Angochitina longicollis Chitinozoan Zone. Zircons giv- ing the latter age are from a bed previously identified as the Osmundsberg K-bentonite at the Kallholn Quarry in the same area. Based on new biostratigraphic data, the latter bed is now considered to be slightly younger than the Osmundsberg K-bentonite. The dated stratigraphic level of the ash layers is slightly younger than the base of the Telychian Stage and thus represents a minimum age for the Aeronian/Telychian Stage boundary. A U-Pb age of 〉 438 ma for the base of this stage, however, is older and in conflict with estimates in the most recent compilation of the Silurian time scale. In view of the fact that only three radio-isotopic dates from the entire Llan- dovery have been previously accepted, this new and biostratigraphically exceptionally well-controlled radio-isotopic date fills an important gap in the Lower Silurian geochronology.

关键词：无线电同位素蓝达夫里阶志留纪

Distribution of Protists in the Deep South China Sea Revealed by High-Throughput Sequencing

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 Ocean University of China 2020年第1期19卷 161-170页

作者： LI Xinran warren Alan JIAO Nianzhi XU Dapeng State Key Laboratory of marine Environmental Science Institute of Marine Microbes and EcospheresCollege of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Department of Life Sciences Natural History MuseumLondonSW75BDUK

Protists(microbial eukaryotes)are indispensable members of the marine microbial food *** recent years,organisms living in the deep sea(>1000 m water depth)have increasingly become the focus of research;however,studies on protistan assemblages are relatively scarce compared with their prokaryotic *** the present study,high-throughput sequencing of the hypervariable V9 region of the 18S rRNA gene was used to explore the community composition of protists in bathypelagic waters of the South China *** on the analysis of the alpha and beta diversities of 14 samples,we discovered:1、members belonging to Rhizaria,Alveolata,and Excavata were the dominant groups in terms of both relative sequence abundance and operational taxonomic unit(OTU)richness in all samples,although their relative contributions differed among different samples;2、cluster analysis showed that the distribution of protistan assemblages was related neither to the sampling location nor to the water depth,and other environmental factors might have caused the differences among the communities;3、phototrophs,including members of the Bacillariophyta,Bolidophyceae,Dictyochophyceae,Prasinophyceae,and Prymnesiophyceae,were detected in all samples,which indicated their contributions to the downward transportation via the biological pump and the potential presence of phagotrophy of these phototrophic cells in the deep ocean.

关键词： bathypelagic water diversity microbial eukaryotes SSU rRNA gene

Transitions of care across hospital settings in patients with inflammatory bowel disease

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2019年第17期25卷 2122-2132页

作者： Leigh R warren Jonathan m Clarke Sonal Arora mauricio Barahona Naila Arebi Ara Darzi Patient Safety Translational Research Centre Imperial College London Department of Surgery and Cancer Imperial College London Centre for Health Policy Imperial College London Centre for Mathematics of Precision HealthcareImperial College London Department of Biostatistics Harvard University Department of mathematics Imperial College London Department of Gastroenterology St.Marks Academic Institute

BACKGROUND Inflammatory bowel disease(IBD) is a chronic, inflammatory disorder characterised by both intestinal and extra-intestinal pathology. Patients may receive both emergency and elective care from several providers, often in different hospital settings. Poorly managed transitions of care between providers can lead to inefficiencies in care and patient safety issues. To ensure that the sharing of patient information between providers is appropriate, timely, accurate and secure, effective data-sharing infrastructure needs to be developed. To optimise inter-hospital data-sharing for IBD patients, we need to better understand patterns of hospital encounters in this *** To determine the type and location of hospital services accessed by IBD patients in *** was a retrospective observational study using Hospital Episode Statistics, a large administrative patient data set from the National Health Service in *** patients with a diagnosis of IBD following admission to hospital were followed over a 2-year period to determine the proportion of care accessed at the same hospital providing their outpatient IBD care, defined as their ‘home provider'. Secondary outcome measures included the geographic distribution of patient-sharing, regional and age-related differences in accessing services, and type and frequency of outpatient ***95055 patients accessed hospital services on 1760156 occasions over a 2-year follow-up period. The proportion of these encounters with their identified IBD‘home provider' was 73.3%, 87.8% and 83.1% for accident and emergency,inpatient and outpatient encounters respectively. Patients living in metropolitan centres and younger patients were less likely to attend their ‘home provider' for hospital services. The most commonly attended specialty services were gastroenterology, general surgery and *** Transitions of care between secondary care settings are common for patients with IBD. E

关键词： Inflammatory bowel disease Crohn's disease Ulcerative colitis Transitions of care Continuity of care Fragmentation multi-morbidity

Investigation of carbon dioxide photoreduction process in a laboratory-scale photoreactor by computational fluid dynamic and reaction kinetic modeling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2022年第7期16卷 1149-1163页

作者： Xuesong Lu Xiaojiao Luo warren A.Thompson Jeannie Z.Y.Tan mmercedes maroto-Valer Research Centre for Carbon Solutions School of Engineering and Physical SciencesHeriot-Watt UniversityEdinburgh EH144ASUK

The production of solar fuels via the photoreduction of carbon dioxide to methane by titanium oxide is a promising process to control greenhouse gas emissions and provide alternative renewable fuels. Although several reaction mechanisms have been proposed, the detailed steps are still ambiguous, and the limiting factors are not well defined. To improve our understanding of the mechanisms of carbon dioxide photoreduction, a multiphysics model was developed using COmSOL. The novelty of this work is the computational fluid dynamic model combined with the novel carbon dioxide photoreduction intrinsic reaction kinetic model, which was built based on three-steps, namely gas adsorption, surface reactions and desorption, while the ultraviolet light intensity distribution was simulated by the Gaussian distribution model and Beer-Lambert model. The carbon dioxide photoreduction process conducted in a laboratory-scale reactor under different carbon dioxide and water moisture partial pressures was then modeled based on the intrinsic kinetic model. It was found that the simulation results for methane, carbon monoxide and hydrogen yield match the experiments in the concentration range of 10^(−4) mol·m^(–3) at the low carbon dioxide and water moisture partial pressure. Finally, the factors of adsorption site concentration, adsorption equilibrium constant, ultraviolet light intensity and temperature were evaluated.

关键词： carbon dioxide photoreduction computational fluid dynamic simulation kinetic model Langmuir adsorption

ExaHDF5: Delivering Efficient Parallel I/O on Exascale Computing Systems

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2020年第1期35卷 145-160页

作者： Suren Byna m.Scot Breitenfeld Bin Dong Quincey Koziol Elena Pourmal Dana Robinson Jerome Soumagne Houjun Tang Venkatram Vishwanath Richard warren Lawrence Berkeley National Laboratory BerkeleyCA 94597U.S.A The HDF Group ChampaignIL 61820U.S.A Argonne National Laboratory LemontIL 60439U.S.A

Scientific applications at exascale generate and analyze massive amounts of data.A critical requirement of these applications is the capability to access and manage this data efficiently on exascale *** I/O,the key technology enables moving data between compute nodes and storage,faces monumental challenges from new applications,memory,and storage architectures considered in the designs of exascale *** the storage hierarchy is expanding to include node-local persistent memory,burst buffers,etc.,as well as disk-based storage,data movement among these layers must be *** I/O libraries of the future should be capable of handling file sizes of many terabytes and *** this paper,we describe new capabilities we have developed in Hierarchical Data Format version 5(HDF5),the most popular parallel I/O library for scientific ***5 is one of the most used libraries at the leadership computing facilities for performing parallel I/O on existing HPC *** state-of-the-art features we describe include:Virtual Object Layer(VOL),Data Elevator,asynchronous I/O,full-featured single-writer and multiple-reader(Full SWmR),and parallel *** this paper,we introduce these features,their implementations,and the performance and feature benefits to applications and other libraries.

关键词： parallel I/O Hierarchical Data Format version 5(HDF5) I/O performance virtual object layer HDF5 optimizations