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Numerical modeling of the transmission dynamics of drug-sensitive and drug-resistant HSV-2

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Communications in Nonlinear Science and Numerical Simulation 2001年第1期6卷 23-27页

作者： A. B. GUMEL(Department of Mathematics, University of Manitoba, Winnipeg, Manitoba, R3t 2N2, Canada ) Department of Mathematics University of Manitoba Winnipeg Manitoba R3T 2N2 Canada

A competitive finite-difference method will be constructed and used to solve a modified deterministic model for the spread of herpes simplex virus type-2 (HSV-2) within a given population. the model monitors the transmission dynamics and control of drug-sensitive and drug-resistant HSV-2. Unlike the fourth-order Runge-Kutta method (RK4), which fails when the discretization parameters exceed certain values, the novel numerical method to be developed in this paper gives convergent results for all parameter values.

关键词： HSV-2 finite-difference initial-value problem numerical instabilities positivity

Study on soils under shifting cultivation and other land use categories in Chittagong Hill tracts, Bangladesh

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Journal of Forestry Research 2012年第2期23卷 261-265页

作者： Alake Biswas M.Alamgir S.M.S.Haque K.t.Osman Department of soil science University of ChittagongChittagong-4331Bangladesh Institute of Forestry and Environmental Sciences University of ChittagongChittagong-4331Bangladesh

Soil samples were collected and analyzed from 25 sites of three hilly regions （Rangamati, Banderban and Khagrachari） for an understanding of the impact of denudation and land use on soils in Chittagong Hill tracts, Bangladesh. there were natural forests, bushy land, slashed sites, slashed and burnt sites, and the sites prepared for shifting cultivation, one year after shifting cultivation and two years after shifting cultivation. the soils were generally yellowish brown to reddish brown, sandy to sandy clay loam, strongly acid, and well to excessively drained on steep slopes with considerable variation among the sites and land use categories. Bulk density was the highest in sites of one year after shifting cultivation （1.52 g·cm^-3） and the lowest in forested sites （1.38 g·cm^-3）. Water holding capacities were, however, statistically similar in all sites. Organic carbon varied from 0.54% （slashed and burnt sites） to 1.55% （forested sites） and total N ranged from 0.05% （shifting cultivation for one year） to 0.13% （forested sites）. Available phosphorus （Bray ＆ Kurtz-2 P） was the maximum in forested sites （12.32 mg·kg^-l）, and it did not differ significantly in other sites. Contents of available Ca, Mg and K were also higher in the bushy lands and forested sites than cleared and shifting cultivated sites.

关键词： Chittagong Hill tracts Bangladesh denudation shifting cultivation soil degradation

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景观与区域生态学的一般原理

生态学杂志 1996年第3期15卷 73-79页

作者： Richard t.t.Forman 李秀珍肖笃宁 Harvard University Graduate School of Design Cambridge MA 02138 USA

1 引言本文的目的是提出关于土地镶嵌体生态学的一些基本原理,作者希望以此引出一些讨论、改进(refinement),替换、补充、假设、探究及更深一步的理解,并帮助阐明它们在多方面应用的基础。景观与区域的生态学为当今社会提供了解决所有... 详细信息

1 引言本文的目的是提出关于土地镶嵌体生态学的一些基本原理,作者希望以此引出一些讨论、改进(refinement),替换、补充、假设、探究及更深一步的理解,并帮助阐明它们在多方面应用的基础。景观与区域的生态学为当今社会提供了解决所有土地利用问题的空间途径。景观生态学的概念开始出现于半个世纪之前(troll,1939,1968;Schreiber,1990)。但因其集理论与应用于一体,近十年来兼收并蓄,取得了蓬勃发展。有关的原理以前也曾经提出过一些。Risser等(1984)与1983年Allerton公园研讨会的同仁们就生态学与景观学融合的几个方面进行了讨论,主要有:①空间格局与生态过程;

关键词：景观生态学区域生态学

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Photo-thermal Model of MALDI Mass Spectrometry and Its Applications and Improvements

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Photo-Thermal Model of MALDI Mass Spectrometry and Its Appli...

An Evaluation of the Adverse Events Following Voluntary Medical Male Circumcision Surveillance System in Zvimba District, Zimbabwe, 2020

中国化学会第27届学术年会

作者： S.t.tsai Y.t.Lee Genomics Research Center Academia Sinica Institute of Atomic and Molecular Sciences Academia Sinica

＜正＞A photo-thermal model of matrix-assisted laser desorption/ionization （MALDI） mass spectrometry was developed. Based on experimental observations, the primary ions are assumed to be produced by proton disproportionation reaction on the substrate. the analyte is protonated via the proton transfer reaction. the heat generated by a laser not only promotes chemical reactions, but also desorbs both neutral molecules and ions. the transition state theory was employed to predict the rate of the desorption process. this model was applied to MALDI experiments with a matrix of 2,4,6-trihydroxyacetophenone and tryptophan as the analyte. the laser fluence dependence of neutral matrix molecules, protonated matrix ions, and protonated analyte ions can be reproduced by the photo-thermal model. Furthermore, MALDI temperatures were also evaluated by the photo-thermal model. the commonly used fluence range of 100-200 corresponds to the temperature of 1844-3388 Kelvin.

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World Journal of AIDS 2022年第1期12卷 1-19页

作者： tendai Hlabangana Owen Mugurungi Emmanuel Govha tsitsi P. Juru Notion t. Gombe Addmore Chadambuka Maurice Omondi Mufuta tshimanga Department of Family Medicine Global and Public Health Unit University of Zimbabwe Harare Zimbabwe AIDS and tB Programmes Directorate Harare Zimbabwe African Field Epidemiology Network Harare Zimbabwe African Field Epidemiology Network Nairobi Kenya

Background: the Adverse Events following Voluntary Medical Male Circumcision Surveillance System (VMMC AESS) serves to identify adverse events (AEs) for safe provision of VMMC. In 2019, Zvimba District reported two adverse events out of 542 circumcisions translating to a 0.4% AE rate against an acceptable threshold of 2% and this is suggestive of underreporting. We evaluated the system to verify existence of underreporting of AEs, assess the surveillance system attributes and evaluate data quality. Methods: A descriptive cross-sectional study was conducted using the updated Center for Disease Control (CDC) guidelines for surveillance system evaluation. We proportionately sampled VMMC client intake records and purposively selected health workers involved in the VMMC programme into the study. An interviewer-administered questionnaire was used to collect data from 14 - 30 December 2020 on knowledge of the VMMC AESS among health care workers and surveillance system attributes. We used a checklist to check for data quality. Data were analysed using Epi Info 7 statistical software. Results: Of the 31 health workers that participated in the study, 21 (68%) had fair knowledge of the surveillance system. Out of 384 records reviewed, 104 had missing data on AE monitoring days 7 and 42. Sixteen (52%) of participants regarded filling AE reporting forms as difficult and the process as time-consuming. the surveillance system was not representative as only two out of eight facilities were conducting outreaches in hard-to-reach areas. Conclusion: there was possible underreporting of adverse events as about a quarter of reviewed records had missing data on AE monitoring days and the system’s performance was threatened by poor data quality and unavailability of reporting forms. the system was rendered acceptable though unstable, not representative and not simple and the health workers were not making use of the surveillance system. We recommended retraining on the surveillance system

关键词： Surveillance Adverse Events System Circumcision Evaluation

Acoustofluidic separation enables early diagnosis of traumatic brain injury based on circulating exosomes

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Microsystems & Nanoengineering 2021年第2期7卷 59-69页

作者： Zeyu Wang Haichen Wang Ryan Becker Joseph Rufo Shujie Yang Brian E.Mace Mengxi Wu Jun Zou Daniel t.Laskowitz tony Jun Huang Department of Mechanical Engineering and Materials Science Duke UniversityDurhamNC27708USA Department of Neurology Duke UniversityDurhamNC27708USA Department of Biomedical Engineering Duke UniversityDurhamNC27708USA Department of Geriatrics Duke UniversityDurhamNC27708USA Department of Electrical&Computer Engineering Texas A&M UniversityCollege StationTX77840USA

traumatic brain injury(tBI)is a global cause of morbidity and *** management and risk stratification of patients with tBI is made difficult by the relative insensitivity of screening radiographic studies as well as by the absence of a widely available,noninvasive diagnostic *** particular,a blood-based biomarker assay could provide a quick and minimally invasive process to stratify risk and guide early management strategies in patients with mild tBI(mtBI).Analysis of circulating exosomes allows the potential for rapid and specific identification of tissue *** applying acoustofluidic exosome separation—which uses a combination of microfluidics and acoustics to separate bioparticles based on differences in size and acoustic properties—we successfully isolated exosomes from plasma samples obtained from mice after *** isolation eliminated interference from other blood components,making it possible to detect exosomal biomarkers for tBI via flow *** cytometry analysis indicated that exosomal biomarkers for tBI increase in the first 24 h following head trauma,indicating the potential of using circulating exosomes for the rapid diagnosis of *** levels of tBI biomarkers were only detected in the samples separated via acoustofluidics;no changes were observed in the analysis of the raw plasma *** finding demonstrated the necessity of sample purification prior to exosomal biomarker *** acoustofluidic exosome separation can easily be integrated with downstream analysis methods,it shows great potential for improving early diagnosis and treatment decisions associated with tBI.

关键词： diagnosis separation injury

Isolation of Picocyanobacteria (Order Synechococcales) and Occurrence of the Cyanotoxin Anatoxin-A in a Shallow Mesotrophic Pond

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Journal of Water Resource and Protection 2023年第9期15卷 299-314页

作者： Nancy J. Leland Kimberley Crocker Pearson Marty K. Burke Jeffrey t. Miller Alison Watts James F. Haney Department of Biological Sciences University of New Hampshire Center for Freshwater Biology and Ecotoxicology Durham New Hampshire USA Lim-tex North Andover Massachusetts USA Brewster Natural Resources Advisory Commission Brewster Massachusetts USA Brewster Ponds Coalition Brewster Massachusetts USA Department of Civil and Environmental Engineering University of New Hampshire College of Engineering and Physical Sciences Durham New Hampshire USA

We have verified the use of a serial filtration method to isolate picocyanobacteria for analysis. We used eDNA metabarcoding to confirm the picocyanobacteria as members of the Order Synechococcales, Genus Cyanobium, specifically Cyanobium 6307. Fluorometric analysis using accessory pigments phycocyanin and phycoerythrin described periods of excess biomass, where the net growth rate model confirmed these conditions. the total anatoxin-a concentrations in the picocyanobacterial sample ranged from 0.0074 - 6.41 μg·L-1 representing a 40-fold difference over the entire sampling season. Sampling frequency of every three days appeared to be an important factor in capturing these changes in anatoxin-a concentration. During a period of excess biomass, we were able to establish a linear correlation between cyanobacterial biomass and Anatoxin-a concentrations.

关键词： Picocyanobacteria Anatoxin-a eDNA Phycocyanin Phycoerythrin

Memristive SRAM cell of seven transistors and one memristor

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Journal of Semiconductors 2016年第10期37卷 56-59页

作者： Patrick W.C.Ho Haider Abbas F.Almurib t.Nandha Kumar Department of Electrical & Electronic Engineering University of Nottingham Malaysia Campus

In this work, a novel memristive SRAM cell is designed using seven transistors and one memristor（7t1M）. In this 7t1 M SRAM cell, the non-volatile functionality is achieved by adding a single memristor and a transistor to the design of a volatile SRAM cell. the designing of the 7t1 M SRAM cell also introduces VCtRL which allows bidirectional current flowing through the memristor, instead of relying on complementary input sources which would require more design components. In this article, memristive SRAM cells available from the literature are simulated using the same simulation environment for a fair comparison. Simulations show that the7t1 M SRAM cell has the least power consumption against other memristive SRAM cells in the literature. the7t1 M SRAM cell operates with an average switching speed of 176.21 ns and an average power consumption of2.9665μW. the 7t1 M SRAM cell has an energy-delay-area product value of 1.61, which is the lowest among the memristive SRAM cells available in the literature.

关键词： memristor memristive SRAM cell EDAP non-volatile memory cell

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Effect of Adsorbent/Adsorbate Couple on the Performance of Adsorption Solar Refrigerator

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Engineering（科研） 2022年第3期14卷 95-112页

作者： Guy Christian tubreoumya Eloi Salmwendé tiendrebeogo Oumar Bailou téré Dabilgou Belkacem Zeghmati Alfa Oumar Dissa Jean Koulidiati Antoine Bere Laboratoire de Physique et de Chimie de l’Environnement (LPCE) Université Joseph Ki Zerbo Ouagadougou Burkina Faso LAboratoire de Mathématiques et Physique (LA.M.P.S) Université de Perpignan Via Domitia (UPVD) Perpignan France

this work presents a contribution to the study of the process of cold production by adsorption from solar energy. In this paper, we discuss a comparative study of the operation of a solar adsorption refrigerator using the silica gel-water couple and the zeolite-water couple through dynamic modeling and simulation. the mathematical model representing the evolution of heat and mass transfer at each component of the adsorption solar refrigerator has been developed. It appears from this study that the evolution of the temperature of the two adsorbents (zeolite and silica gel) is quasi-similar throughout the operating cycle. However, the maximum mass of water vapor adsorbed by the silicagel (0.24 kg/kg) is higher than that adsorbed by the zeolite (0.201 kg/kg). In the same way, the mass of water vapor cycled, obtained with the silicagel-water couple which is 0.14 kg/kg, is higher than that obtained with the zeolite-water couple which is 0.081 kg/kg. therefore, the amount of cold produced 9.178 MJ and the solar coefficient of performance 0.378 obtained with the solar refrigerator using the silica gel-water couple, are better.

关键词： Solar Cooling Adsorption Zeolite Silica Gel Water Heat and Mass transfer