检索结果-南通市图书馆

2-d eddy resolving simulations of flow past a circular array of cylindrical plant stems

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2018年第2期30卷 317-335页

作者： Kyoungsik Chang george Constantinescu Sanghyun Park School of Mechanical Engineering Ulsan University Ulsan Korea Civil and Environmental Engineering department IIHR-Hydroscience and Engineering Stanley Hydraulics Laboratory The University of Iowa Iowa City USA Korea Aerospace Research Institute Daejeon Korea

In the present study, 2-d large eddy simulations（LES） are conducted for flow past a porous circular array with a solid volume fraction（SVF） of 8.8%, 15.4% and 21.5%. Such simulations are relevant to understanding flow in natural streams and channels containing patches of emerged vegetation. In the simulations discussed in the paper, the porous cylinder of diameter d contains a variable number of identical solid circular cylinders（rigid plant stems） of diameter d= 0.048 d. Most of the simulations are conducted at a Reynolds number of 2 100 based on the diameter d and the velocity of the steady uniform incoming flow. Though in all cases wake billows are shed in the regions where the separated shear layers（SSLs） forming on the sides of the porous cylinder interact, the effect of these wake billows on the mean drag is different. While in the high SVF case（21.5%）, the total drag force oscillates quasi-regularly in time, similar to the canonical case of a large solid cylinder, in the cases with a lower SVF the shedding of the wake billows takes place sufficiently far from the cylinder such that the unsteady component of the total drag force is negligible. The mean amplitude of the oscillations of the drag force on the individual cylinders is the largest in a streamwise band centered around the center of the porous cylinder, where the wake to wake interactions are the strongest. In all cases the maximum drag force on the individual cylinders is the largest for the cylinders directly exposed to the flow, but this force is always smaller than the one induced on a small isolated cylinder and the average magnitude of the force on the cylinders directly exposed to the flow decreases monotonically with the increase in the SVF. Predictions of the global drag coefficients, Strouhal numbers associated with the wake vortex shedding and individual forces on the cylinders in the array from the present LES are in very good agreement with those of 2-d direct numerical simulations conduc

关键词： Vegetation eddy resolving simulation solid volume fraction porous cylinder bleeding flow

The effectiveness of the department of defense's field manual 3-11 in detecting,deterring and degrading the breach of a combat base by a human-borne with bioagent(HBBA):perceptions of security personnel

在线全文

学校读者我要写书评

暂无评论

Journal of Medical Colleges of PLA(China) 2016年第2期31卷 66-72页

作者： george Edafese Alakpa John W.Collins jr department of Professional Security Studies New Jersey City University

Background: The department of defense's field manual(FM) 3-11 is among the military's field manuals for preparing for, reacting to and recovering from chemical, biological, radiological and nuclear attacks. Since post 9-11, U.S. military service members have been deployed in the global war on terrorism. This study attempted to determine the effectiveness of the FM 3-11 in detecting, deterring or preventing a human-borne with bioagent(HBBA) terrorist breach at an entry control point(ECP).Methods: This time-specific, cross-sectional study disseminated a validated survey tool with Cronbach's α>0.82 to respondents who have had antiterrorism training and combat ECP experience. The return rate was greater than 75.0%; however, many of the respondents failed to meet the inclusion criteria. Consequently, only 26 questionnaires were included in the ***: The results revealed that while over 60.0% of the respondents either strongly agreed or agreed that biointelligence, the deployment of biodetectors and the use of biowarning systems could be effective in preventing an ECP breach by a terrorist with a bioagent, the use of protective equipment and immunization to decontaminate service members or other tactics, techniques and procedures(TTPs) would never prevent a breach. A large percentage of respondents claimed that soldiers at the ECP lacked the devices or the knowledge to detect an HBBA at an ECP, and 72.0% suggested modifying current ECP TTPs to include education, training and equipment for security personnel at military base ***: If obtained from appropriate sources and communicated to the personnel at the ECP in an effective or timely manner, the possible effectiveness of certain TTPs in the FM 3-11, specifically FM 3-11.86(intelligence), might increase.

关键词： do d FM 3-11 Bioterrorism Breach of Combat ECP HBBA terrorist Security personnel Perception

Effects of a regenerating matrix on the survival of birds in tropical forest fragments

在线全文

学校读者我要写书评

暂无评论

Avian Research 2020年第1期11卷 16-24页

作者： Jared d.Wolfe Philip C.Stouffer Richard O.Bierregaard jr david A.Luther Thomas E.Lovejoy College of Forest Resources and Environmental Science Michigan Technological UniversityHoughtonMI 49931USA Biological dynamics of Forest Fragments Project Instituto Nacional de Pesquisas da AmazoiaManaus 69011Brazil College of Renewable Natural Resources Louisiana State University AgCenterLouisiana State UniversityBaton RougeLA 70803USA Biology department George Mason University4400 University Drive MS3EFairfaxVA 22030USA

Background: Vast areas of lowland neotropical forest have regenerated after initially being cleared for agricultural purposes. The ecological value of regenerating second growth to forest-dwelling birds may largely depend on the age of the forest, associated vegetative structure, and when it is capable of sustaining avian demographics similar to those found in pristine ***: To determine the influence of second growth age on bird demography, we estimated the annual survival of six central Amazonian bird species residing in pristine forest, a single 100 and a single 10 ha forest fragment, taking into consideration age of the surrounding matrix(i.e. regenerating forest adjacent to each fragment) as an explanatory ***: Study species exhibited three responses: arboreal, flocking and ant-following insectivores(Willisornis poecilinotus, Thamnomanes ardesiacus and Pithys albifrons) showed declines in survival associated with fragmentation followed by an increase in survival after 5 years of matrix regeneration. Conversely, Percnostola rufifrons, a gap-specialist, showed elevated survival in response to fragmentation followed by a decline after 5 years of regeneration. Lastly, facultative flocking and frugivore species(Glyphorynchus spirurus and dixiphia pipra, respectively) showed no response to adjacent clearing and subsequent ***: Our results in association with previous studies confirm that the value of regenerating forest surrounding habitat patches is dependent on two factors: ecological guild of the species in question and second growth age. Given the rapid increase in survival following succession, we suggest that the ecological value of young tropical forest should not be based solely on a contemporary snapshot, but rather, on the future value of mature second growth as well.

关键词： Amazon fragmentation Brazil Matrix Second growth Survival Tropical bird

Identifying survival protective factors for chronic dialysis patients with surgically confirmed acute mesenteric ischemia

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2022年第8期14卷 809-820页

作者： Shuh-Kuan Liau george Kuo Chao-Yu Chen Yueh-An Lu Yu-jr Lin Cheng-Chia Lee Cheng-Chieh Hung Ya-Chung Tian Hsiang-Hao Hsu department of Nephrology Kidney Research CenterChang Gung Memorial HospitalLinkou BranchCollege of MedicineChang Gung UniversityTaoyuan 333Taiwan Research Services Center for Health Information Chang Gung UniversityTaoyuan 333Taiwan

BACKGROUNd Mesenteric ischemia is significantly more common in end-stage kidney disease patients undergoing chronic dialysis than in the general population and is associated with high morbidity and mortality. However, reports on prognostic factors in this population are *** To elucidate the in-hospital outcomes of acute mesenteric ischemia in chronic dialysis patients and to analyze protective factors for *** The case data of 426 chronic dialysis patients who were hospitalized in a tertiary medical center for acute mesenteric ischemia over a 14-year period were retrospectively reviewed. Of these cases, 103 were surgically confirmed, and the patients were enrolled in this study. A Cox regression analysis was used to evaluate the protective factors for *** The in-hospital mortality rate among the 103 enrolled patients was 46.6%.Univariate analysis was performed to compare factors in survivors and nonsurvivors, with better in-hospital outcomes associated with a surgery delay(defined as the time from onset of signs and symptoms to operation) d, no shock, a higher potassium level on day 1 of hospitalization, no resection of the colon, and a total bowel resection length d cell count and neutrophil counts, higher lymphocyte counts, and lower C-reactive protein levels had better in-hospital outcomes. Following multivariate adjustment, a higher potassium level on day 1 of hospitalization(HR 1.71, 95%CI 1.19 to 2.46;P = 0.004), a lower neutrophil count(HR 0.91, 95%CI 0.84 to 0.99;P = 0.037) at 1 wk after admission, resection not involving the colon(HR 2.70, 95%CI 1.05 to 7.14;P = 0.039), and a total bowel resection length d with *** A surgery delay d, no shock, no resection of the colon, and a total bowel resection length dicted better outcomes in chronic dial

关键词： Mesenteric ischemia Chronic dialysis End-stage kidney disease Surgery Protective factors Survival

Comparison of TRMM and Water district Rain Rates over New Mexico

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2006年第1期23卷 1-13页

作者： Long S. CHIU Zhong LIU Jearanai VONGSAARd stanley MORAIN Amy BUdGE Paul NEVILLE Chandra BALES NASA/Goddard Space Flight Center Distributed Active Archive Center Greenbelt Maryland 20771 USA Center for Earth Observing and Space Research School of Computational Sciences George Mason University Fairfax Virginia 22030-4444 USA Earth data Analysis Center University of New Mexico Albuquerque New Mexico 87131 USA Thai Royal Military Academy Bangkok Thailand

This paper compares monthly and seasonal rain rates derived from the Version 5 （V5） and Version 6 （V6） TRMM Precipitation Radar （TPR, TSdIS reference 2A25）, TRMM Microwave Imager （TMI, 2A12）, TRMM Combined Instrument （TCI, 2B31）, TRMM calibrated IR rain estimates （3B42） and TRMM merged gauge and satellite analysis （3B43） algorithms over New Mexico （NM） with rain gauge analyses provided by the New Mexico water districts （Wd）. The average rain rates over the NM region for 1998- 2002 are 0.91 mm d^-1 for Wd and 0.75, 1.38, 1.49, 1.27, and 1.07 mm d^-1 for V5 3B43, 3B42, TMI, PR and TCA; and 0.74, 1.38, 0.87 and 0.97 mm d^-1 for V6 3B43, TMI, TPR and TCA, respectively. Comparison of V5 3B43 with Wd rain rates and the daily TRMM mission index （TPR and TMI） suggests that the low bias of V5 3B43 for the wet months （summer to early fall） may be due to the non-inclusion of some rain events in the operational gauge analyses that. are used in the production of V5 3B43. Correlation analyses show that the Wd rain rates vary in phase, with higher correlation between neighboring Wds. High temporal correlations （〉0.8） exist between Wd and the combined algorithms （3B42, 3B43 and TCA for both V5 and V6） while satellite instrument algorithms （PR, TMI and TCI） are correlated best among themselves at the monthly scale. Paired t-tests of the monthly time series show that V5 3B42 and TMI are statistically different from the Wd rain rates while no significant difference exists between Wd and the other products. The agreements between the TRMM satellite and Wd gauge estimates are best for the spring and fall and worst for winter and summer. The reduction in V6 TMI （-7.4%） and TPR （-31%） rain rates （compared to V5） results in better agreement between Wd estimates and TMI in winter and TPR during summer.

关键词： satellite precipitation TRMM Water district New Mexico surface rain

Molecular docking Studies on Anticonvulsant Enaminones Inhibiting Voltage-Gated Sodium Channels

在线全文

学校读者我要写书评

暂无评论

Open Journal of Physical Chemistry 2019年第4期9卷 241-257页

作者： Yayin Fang Jamiya Kirkland Isis J. Amaye Patrice Jackson-Ayotunde Matthew george jr. department of Biochemistry and Molecular Biology College of Medicine Howard University Washington DC USA department of Pharmaceutical Sciences School of Pharmacy and Health Professions University of Maryland Eastern Shore Princess Anne MD USA

Epilepsy is described as the most common chronic brain disorder. A typical symptom of epilepsy results in uncontrolled convulsions caused by temporary excessive neuronal discharges. Although several new anticon-vulsants have been introduced, some types of seizures have still not been adequately controlled with these new and current therapies. There is an urgent need to develop new anticonvulsant drugs to control the many different types of seizures. Many studies have shown that the epilepsies involve more than one mechanism and therefore may be responsible for the various types of observed seizures. Recently reported studies have shown that a group of newly synthesized 6 Hz active anticonvulsant fluorinated N-benzamide enaminones exhibited selective inhibitions of voltage-gated sodium (Nav) channels. Nav channels are responsible for the initial inward currents during the depolarization phases of the action potential in excitable cells. The activation and opening of Nav channels result in the initial phases of action potentials. We hypothesize that there is an essential pharmacophore model for the interactions between these enaminones and the active sites of Nav channels. The research reported here is focused on molecular docking studies of the interactions that occur between the fluorinated N-benzamide enaminones and the Nav channels. These studies may open an avenue for designing anticonvulsant drugs by inhibiting Nav channels.

关键词： Anticonvulsant Enaminones Voltage-Gated Sodium Channels Structure-Based drug design Molecular docking 3d QSAR

Subclinical atherosclerosis in northern and southern China： the Chinese paradox

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 Geriatric Cardiology 2011年第2期8卷 72-77页

作者： Jie Huang Yang-Feng Wu Xiao-Qing Liu ding ding Lian-Cheng Zhao Bin Lu Xian Li Nathan d Wong Laurie d dustin stanley P Azen Robert C detrano Clinical Research Institute and Key Lab of Health Technology Assessment of Ministry of Health School of Public Health Fudan University Shanghai 200032 China Peking University School of Public Health and the george Institute for Global Health Beijing 100083 China Guangdong Provincial People＇s Hospital Guangzhou 510030 Guangdong Province China Hua Shan Hospital Fudan University Shanghai 200040 China Cardiovascular Institute and Fuwai Hospital Beijing 100004 China division of Cardiology University of California Irvine CA 92697 USA department of Preventive Medicine Keck School of Medicine University of Southern California Los Angeles CA 90089-0080 USA department of Radiology School of Medicine University of California Irvine CA 92697 USA

Background The incidence of coronary heart disease （CHd） is higher in Northern than that in Southern China, however differences in traditional CHd risk factors do not fully explain this. No study has examined the differences in subclinical atherosclerosis that may help explain the differences in incidence. This study examined these differences in subclinical atherosclerosis using coronary computed tomography （CT） for calcification between the Northern and Southern China. Methods We selected a random sample of participants in a large multi-center ongoing epidemiologic study for coronary calcium scanning in one northern city （North）（Beijing, n = 49） and in two southern cities （South）（Shanghai, n = 50, and Guangzhou, n = 50）. Participants from the three field centers （mean age 67 years） underwent coronary risk factor evaluation and cardiac CT scanning for coronary calcium measurement using the Multi-Ethnic Study of Atherosclerosis scanning protocol. Results Adjusted log-transformed coronary artery calcium score in North China （Beijing） was 3.1 ±0.4 and in South China （Shanghai and Guangzhou） was 2.2 ＋_ 0.3 （P = 0.04）. Mean calcium score for the northern city of Beijing was three times higher than that of the southern city of Guangzhou （P = 0.01） and 2.5 times higher than for the southern city of Shanghai （P = 0.03）. Conclusions The extent of subclinical atherosclerosis is significantly higher in the northern city of Beijing than that in the two southern cities of Guangzhou and Shanghai, even after adjusting for standard cardiac risk factors. This finding suggests that standard risk factors do not fully explain north south differences in clinical CHd incidence.

关键词： coronary calcium CT scanning atherosclerosis epidemiology China

Molecular docking Studies on Streptomycin Antileishmanial Activity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Physical Chemistry 2024年第2期14卷 36-48页

作者： Todd A. Young Matthew george jr. Ayele Gugssa William M. Southerland Yayin Fang Clarence M. Lee department of Biology Howard University Washington DC United States department of Biochemistry and Molecular Biology Howard University Washington DC United States

Resistance to pentavalent antimonial drugs and the lack of vaccines make it urgent to find novel therapeutic options to treat Leishmaniasis, a tropical disease caused by the Leishmania protozoan parasite. The study reported here is to investigate if Streptomycin, an aminoglycoside, and Amphotericin B, the second-line treatment drug, exhibit antileishmanial activity through a similar mechanism. By using MOE (Molecular Operating Environment), we performed molecular docking studies on these drugs binding to a range of targets including ribosome targets in Leishmania and H. sapiens. Our study shows that the two drugs do not bind to the same pockets in Leishmania targets but to the same pockets in the human ribosome, with some differences in interactions. Moreover, our 2d maps indicated that Amphotericin B binds to the A-site in the human cytoplasmic ribosome, whereas streptomycin does not.

关键词： Leishmaniasis Streptomycin Amphotericin B Molecular docking Aminoglycosides Antileishmanial

discovery of a non-adenylating acyl-CoA ligase and restoring its adenylation activity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Discovery of a non-adenylating acyl-CoA ligase and restoring...