检索结果-南通市图书馆

Detailing the Structure of Liquid THF Based on an EPSR Study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computational Chemistry 2015年第1期3卷 1-7页

作者： Alexandre Borges joao M.M.Cordeiro Department of Physics and Chemistry Sao Paulo State UniversityIlha SolteiraBrazil

The structure of pure liquid tetrahydrofuran (THF) has been investigated via Monte Carlo simulations in the wake of a previous Empirical Potential Structure Refinement (EPSR) study on that liquid (Bowron, D.T.;Finney, J.L.;Soper, A.K. (2006) J. Am. Chem. Soc., 128, 5119). The molecules are allatoms rigid structures and the intermolecular potential used is described for the classical 6-12 Lennard-Jones plus Coulomb in the NPT ensemble at 1 atm and 25°C. THF is a poorly structured liquid. Typical preferred orientation of molecules has been explored and calculations shown different types of molecular pairs exist concurrently in the liquid. The geometry of those pairs was deeply investigated and its influence in the liquid structure discussed. The lack of molecular organization in the liquid is closely related to the existence of that diversity of molecular pairs. Its geometry changes from antiparallel up to T-like depending on the distance between the molecules in the pairs.

关键词： Monte Carlo Simulations Tetrahydrofuran Liquid Structure

Pesticides Exposure:The Case of Workers on Growing Grapes in San Francisco Valley,Petrolina/Brazil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2014年第10期5卷 805-812页

作者： Francisco Alves Pinheiro paulo Jose Adissi Department of Production Engineering Federal University of San Francisco ValleyJuazeiroBrazil Department of Production Engineering Federal University of ParaibaJoao PessoaBrazil

The objective of this work is to analyze the systems of application of pesticides used in harvesting grapes of the sub-medium San Francisco valley, in relation to the risks of occupational contamination. The manual, mechanized and semi mechanized systems of application, adopted by the grape growers of the city of Petrolina/PE, have been analyzed through a method of both quantitative and qualitative evaluation. In such a way, two production units were visited: a mid-sized company and another one from of the CODEVASF. Five simulations were carried out in four systems of pesticide application using the European entire body method. Pre-application processes, such as storage and dilution of pesticides, as well as post-application processes, including equipment maintenance, cleaning and storage of clothes used for the application process were also analyzed. The results show large differences in risk among the systems that were analyzed and better conditions offered by the agricultural company, which was seeking to obtain the certification process.

关键词： Agricultural Work Growing Grapes Chemical Risk Pesticides Exposure

Prevalence of Giardia duodenalis among dogs seized by the Center for Control of Zoonoses (CCZ) of the city of Lages, Santa Catarina, Brazil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Health 2013年第1期5卷 119-124页

作者： Rosileia Marinho Quadros paulo Henrique Exterckotter Weiss Geison Willian Ezequiel Renato Batista Tamanho Geanice Lepo Marcio Rodrigues da Silva Carlos Roberto joao da Silva Junior Flavio Antonio Pacheco de Araujo Luiz Claudio Miletti Universidade do Estado de Santa Catarina LagesBrazil

The knowledge of the epidemiology of parasitic infections in stray and domestic animals, especially of its incidence and prevalence, is fundamental to adopting effective prophylactic measures. Stray dogs play an important role in environmental contamination favoring the transmission cycle of zoonotic agents. Among the parasitic infections that affect humans, Giardia duodenalis is the most common intestinal protozoa and was designated as a re-emerging infectious disease. This study aimed to determine the prevalence of G. duodenalis in dogs siezed by the Center for Control of Zoonoses (CCZ) of the city of Lages, Santa Catarina, Brazil using two diagnostic techniques. In 357 stool samples analysed, the prevalence of G. duodenalis cysts was 5.3% (19/357) and 4.8% (17/357) detected by floatation and sedimentation techniques, respecttively. No correspondence between gender and age was found among the methods used for analyzing the infected dogs in this study. Our data suggested that two diagnostic techniques should be used in a complementary way to ensure that false negatives are not neglected.

关键词： Giardia Duodenalis Dogs Zoonoses Brazil

Bone marrow-derived mesenchymal stem cells versus adipose-derived mesenchymal stem cells for peripheral nerve regeneration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2018年第1期13卷 100-104页

作者： Marcela Fernandes Sandra Gomes Valente Rodrigo Guerra Sabongi joao Baptista Gomes dos Santos Vilnei Mattioli Leite Henning Ulrich Arthur Andrade Nery Maria José da Silva Fernandes Division of Hand and Upper Limb Surgery Department of Orthopedics and Traumatology Universidade Federal de Sao Paulo Sao Paulo Brazil Department of Biochemistry Institute of Chemistry Universidade de Sao Paulo Sao Paulo Brazil Division of Neurosciences Department of Neurology and Neurosurgery Universidade Federal de Sao Paulo Sao Paulo Brazil

Studies have confirmed that bone marrow-derived mesenchymal stem cells （MSCs） can be used for treatment of several nervous system diseases. However, isolation of bone marrow-derived MSCs （BMSCs） is an invasive and painful process and the yield is very low. Therefore, there is a need to search for other alterative stem cell sources. Adipose-derived MSCs （ADSCs） have phenotypic and gene expression profiles similar to those of BMSCs. The production of ADSCs is greater than that of BMSCs, and ADSCs proliferate faster than BMSCs. To compare the effects of venous grafts containing BMSCs or ADSCs on sciatic nerve injury, in this study, rats were randomly divided into four groups： sham （only sciatic nerve exposed）, Matrigel （MG; sciatic nerve injury ＋ intravenous transplantation of MG vehicle）, ADSCs （sciatic nerve injury ＋ intravenous MG containing ADSCs）, and BMSCs （sciatic nerve injury ＋ intravenous MG containing BMSCs） groups. Sciatic functional index was calculated to evaluate the function of injured sciatic nerve. Morphologic characteristics of nerves distal to the lesion were observed by toluidine blue staining. Spinal motor neurons labeled with Fluoro-Gold were quantitatively assessed. Compared with sham-operated rats, sciatic functional index was lower, the density of small-diameter fibers was significantly increased, and the number of motor neurons significantly decreased in rats with sciatic nerve injury. Neither ADSCs nor BMSCs significantly improved the sciatic nerve function of rats with sciatic nerve injury,increased fiber density, fiber diameters, axonal diameters, myelin sheath thickness, and G ratios （axonal diameter/fiber diameter ratios） in the sciatic nerve distal to the lesion site. There was no significant difference in the number of spinal motor neurons among ADSCs, BMSCs and MG groups. These results suggest that neither BMSCs nor ADSCs provide satisfactory results for peripheral nerve repair when using MG as the conductor for engraftment.

关键词： nerve regeneration mesenchymal stem cells adipose-derived mesenchmal stem cells sciatic nerve Matrigel sciatic functional index neural regeneration

Failure of Semi-infinite Beams of Variable Thickness and Curvature on Elastic Foundation under Contact Loading

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Civil Engineering and Architecture 2013年第2期7卷 174-184页

作者： joao Batista De Aguiar Jose Manoel De Aguiar Department of Engenharia AeroEspaeial Universidade Federal do ABC Santo Andre 09210-170 Brazil Department of Ensino Geral Faculdade de Teenologia de Sao Paulo Sao Paulo 01124-060 Brazil

In early winter it is usual, in cold regions, that ice features approach offshore structures, like offshore platforms, impacting them, in a slow process of constant deformation build up. Interaction follows, in many cases, up to the point where ice-failure caused by bending fracture takes place. This supposes very large contact forces that the structure has to resist. Therefore, quantification of these efforts is of vital importance to the structural design of platforms. In several designs, these platforms are constructed with inclined walls so as to cause ice to fail in a flex-compression mode. In such a case the ice feature is analyzed as a beam constituted of a linear elastic material in brittle state with constant ice thickness. The simplification renders the problem solvable in a close form. However, this hypothesis goes against field observations. Marine currents action, wind and the sequence of contacts among features lead to thickness variations. Here this factor is addressed in the construction of a model, for harmonic forms of variation of thickness profile, and the accompanying curvature variations, whose solution determines field variables used to address the failure question. Due to the deformation dependency of the loading, a numerical scheme for the two-point boundary value problem in the semi-infinite space is developed. Failure pressures are computed based on a Rankine locus of failure. Variations of the order of 20% in the failure loads, as compared to the uniform beam model, are observed.

关键词： Ice beams thickness variation elastic behavior frictional contact bending failure loads.

The Effect of Nano-Alumina Particles Generated in Situ in the Matrix of Ultralow and No Cement 85 wt%Al_(2)O_(3) Refractory Castables

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 Materials Science and Chemical Engineering 2019年第6期7卷 7-22页

作者： José Antonio Alves Júnior joao Baptista Baldo Department of Materials Engineering Federal University of Sao Carlos via Washington LuisSao CarlosSPBrazil

Advanced high alumina refractory castables of ultra-low and to cement types, are well-known because of their ability on developing similar and/or superior thermal and mechanical properties. Following the recent trend of including nanoparticles in refractory castables, in this work, it is presented a novel way to obtain the benefit effects on the thermal and mechanical properties, promoted by the development in situ, of alumina’s nanoparticles in the matrix of castable (85 wt% Al2O3). The alumina nanoparticles were originated in situ after firing, due to the pyrolysis and oxidation of an aqueous resin, produced by the Pechini process. The resin played a double role, one as mixing liquid vehicle and the other as the aluminum oxide nanoparticles precursor. The results indicate a strong increase in flexural strength and elastic modulus as well as leading to a higher residual strength after thermal shock.

关键词： Low Cement Refractory Castable Alumina Nanoparticles Elastic Modulus Impulse Excitation Technique

Characteristics of Steps and Analysis of the Technical Procedure of the Block in Middle Men’s Volleyball Players

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 Sports Science 2019年第4期7卷 123-133页

作者： Rui Pinto Susana Vale paulo Vicente joao Centre for Research and Innovation in Education(inED)of Escola Superior de Educacao of Politécnico do Porto Porto 4000Portugal Research Center for Sport Sciences Health and Human Development(CIDESD)University of Trás-os-Montes e Alto DouroVila Real 5000Portugal

In modern volleyball,the middle blocker is regarded as one of the most important players for the tactical organization,because he is frequently requested for both defensive and offensive *** the block action,the coach must always consider the characteristics of the middle blocker,and his intervention should contemplate the ball tempo and the zone where the opposing attack *** purpose of this study is to understand what the movements are that precede the action of the technical gesture of the *** sample consisted of n=4,895 actions representing 30 footages of games from the 1st male volleyball division in the Portuguese league from season 2013/*** have analyzed the movements that each middle blocker has performed during the pre-block *** have also recorded the ball tempo on the opposing setter and the zone where the opposing attack *** have established that there is a relationship between the movements performed and the attack zones(p≤0.001),as well as between the movements and the type of setting,in each attack zone(p≤0.001 in all of them).This way,we have determined that the Crossover Step is the most frequent movement,followed by the Drive Step.

关键词： Volleyball movements middle blocker block

Atlas of precipitation extremes for South America and Africa based on depth-duration-frequency relationships in a stochastic weather generator dataset

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 Soil and Water Conservation Research 2023年第4期11卷 726-742页

作者： Andrew Fullhart David C.Goodrich Menberu B.Meles paulo Tarso S.Oliveira Cristiano das Neves Almeida JoséC.de Araújo Shea Burns Southwest Watershed Research Center USDA-ARS 2000 E.Allen Rd.TucsonAZ85719United States Sustainable Agricultural Water Systems Unit USDA-ARS 239 Hopkins RoadDavisCA95616United States Faculty of Engineering Architecture and Urbanism and GeographyUniversidade Federal de Mato Grosso do SulCampo GrandeMS79070-900Brazil Water Resources and Environmental Engineering Laboratory Universidade Federal da ParaíbaJoao PessoaPB58051-900Brazil Department of Agricultural Engineering Campus do Pici Fortaleza Universidade Federal do CearáFortaleza60020-181Brazil

Information about extreme rainfall is lacking in regions of South America and *** study attempts to fill this scientific gap by use of a gridded parameterization for the stochastic weather generator,CLIGEN,to map depth-duration-frequency(DDF)*** of 500-year point-scale precipitation time series generated at each grid point allowed maps of return period precipitation to be produced for a se-lection of sixteen durations ranging from 10-min to 1-year and for nine return periods from 2 to 500 *** generalized extreme value(GEV)probability distribution was fitted for all durations,and given GEV quantiles,an interpolation method was applied to produce maps at 0.1° resolution that better resolve small-scale spatial climate *** addition to uncertainties related to GEV fitting,this study quantifies prediction intervals based on ground *** validation was important for identifying biases in CLIGEN,although uncertainties were not always satisfactorily defined due to sampling design and other *** daily/multi-day durations,100 stations with daily observations and ≥50-year records were selected for validation against the 0.1° CLIGEN map series,resulting in a median and average absolute error of 13%and 16%,*** sub-daily durations,prediction errors were larger *** analogy using available *** established the degree of bias in CUGEN for sub-daily durations,and three records in Brazil with high temporal resolutions were used to confirm that applied bias adjustments resulted in error ranges similar to the daily/multi-day *** atlas is freely available for study of extreme precipitation.

关键词： Africa Depth-duration-frequency Extreme precipitation South America

Sensory Profile of Fermented Arabica Coffee in the Perception of American Cupping Tasters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2019年第3期10卷 321-329页

作者： Lucas Louzada Pereira Rogério Carvalho Guarconi Tais Rizzo Moreira Dério Brioschi Jr. joao paulo Pereira Marcate Luiz Henrique Bozzi Pimenta de Sousa Aldemar Polonini Moreli Danieli Grancieri Debona Carla Schwengber Ten Caten Federal Institute of Education Science and Technology of Espírito Santo Venda Nova do Imigrante CampusFood Science and Technology ProgramRua Elizabeth Minete PerimVitóriaBrazil Capixaba Institute for Technical Assistance Research and ExtensionINCAPERDepartment of StatisticsDomingos MartinsBrazil Department of Forest Sciences and Wood Federal University of Espirito SantoCenter for Agrarian Sciences and EngineeringJeronimo MonteiroBrazil Department of Production and Transportation Engineering Federal University of Rio Grande do SulPorto AlegreBrazil

The consumption of specialty coffees has been growing year after year, indicating that several niches and market forms according to the sensorial orientation of the consumers, as well as the cupping tasters and agents are responsible for the composition of blends, and for the physical and sensory classification of the coffees in the industry. This study presented 5 methods of spontaneous and induced fermentation to different North American cupping tasters, in order to evaluate coffee quality potential, based on the Specialty Coffee Association (SCA) protocol. During the months of May to July of 2017, 150 coffee samples were evaluated. Initial results indicate that North American cupping tasters evaluated dry fermented coffees using yeast culture as superiors, in the sensorial aspect, than the more conventional methods in Brazil. Such indication opens new discussions on the acceptance of a determined product, followed by the potential for modification of the sensory route as of the fermentation that will affect the attributes.

关键词： Arabica Coffee Fermentation Acceptance Cupping Tasters