检索结果-南通市图书馆

Effect of Polishing Procedure on the Roughness and Bacterial Adhesion of Provisional Restorative Materials

Microscopy Research 2018年第2期6卷 9-18页

作者： néstor usiel lara-jara Gabriel Fernando Romo-Ramírez María del Pilar Goldaracena-Azuara Antonio Aragón-Pi&ntilde a Claudia Butrón-Téllez Girón María Verónica Méndez-González Ana María González-Amaro Faculty of Stomatology Autonomous University of San Luis Potosí San Luis Potosí City México Faculty of Engineering Institute of Metallurgy Autonomous University of San Luis Potosí San Luis Potosí City México Laboratory of Biochemistry Microbiology and Pathology Faculty of Stomatology Autonomous University of San Luis Potosí San Luis Potosí City México

Provisional prosthetic restoration materials are exposed to oral cavity producing on the surface biofilm where different factors such as surface roughness and porosity can condition their formation and organization and can create stagnation areas that promote the bonding of organic particles, thus facilitating the formation and maturation of the biofilm. The purpose of this study was to compare surface roughness of two provisional prosthetic restorations materials and their bacterial susceptibility. In this study, two provisional restoration materials were used in two groups, A polymethyl methacrylate acrylic (nicTone MDC DEnTAL) and B bis-acryl resin (Protemp 4 ESPE 3M). A total of 80 samples (40 samples of each material) were in thick plates of 10 × 10 mm and 2 mm high. 20 samples of each material were polished, while 20 were left unpolished. Subsequently, the samples were observed by Atomic Force Microscopy for their evaluation of surface roughness. The values were analyzed with t-test, Mann-Whitney U test and Kruskal Wallis test. The samples were microbiologically inoculated with the strains obtained and identified from a provisional polymethyl methacrylate acrylic restoration in a patient, in order to observe bacterial adhesion using a Scanning Electron Microscope. Two strains, Enterococcus faecalis and Pseudomona luteola, were identified. The presence of the microorganisms was observed on the surface of both materials, either polished or unpolished, with a lower level of microorganism adhesion found on the bis-acrylic resin. There was a significant difference about surface roughness in the groups A and B with p -8). We found that the polished bis-acrylic resin showed lower surface roughness and bacterial adhesion in comparison with the polymethyl methacrylate.

关键词： Surface Analysis Bacterial Adhesion Provisional Fixed Restoration

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The pitfalls in electrocatalytic nitrogen reduction for ammonia synthesis

引用

Journal of Energy Chemistry 2021年第10期30卷 149-154,I0005页

作者： Huimin Liu néstor Guijarro Jingshan Luo Institute of Photoelectronic Thin Film Devices and Technology Solar Energy Research CenterKey Laboratory of Photoelectronic Thin Film Devices and Technology of TianjinMinistry of Education Engineering Research Center of Thin Film Photoelectronic TechnologyRenewable Energy Conversion and Storage CenterNankai UniversityTianjin 300350China Institute of Electrochemistry University of AlicanteAlicante E-03080Spain

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(EC-nRR)has gained momentum in recent years fueled by its potential to operate at ambient conditions,unlike the highly energyintensive yet long-standing Haber-Bosch ***,the large disparity of the yields and Faradic efficiencies reported for EC-nRR raises serious concerns about the reliability of the experimental *** this perspective,we elaborate on the potential sources of error when assessing EC-nRR and update the testing protocols to circumvent them,and more importantly,we pose a general call for consensus on ammonia production analysis and reporting to lay the solid foundations that this burgeoning field requires to thrive.

关键词： Electrocatalytic nitrogen reduction Ammonia synthesis Pitfalls Standard protocols

来源：

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

Glacier reconstruction of La Covacha Massif in Sierra de Gredos(central Spain) during the Last Glacial Maximum

引用

Journal of Mountain Science 2019年第6期16卷 1336-1352页

作者： néstor CAMPOS David PALACIOS Luis M.TAnARRO Department of Geography Complutense University of Madrid

A paleoglacier reconstruction during the Last Glacial Maximum(LGM) is presented for a high mountain area of La Covacha massif in Sierra de Gredos(Iberian Central System) in central Spain. The moraines that, according with the previous literature, had formed during the global LGM, were mapped through photo interpretation of digital aerial photographs and 3D images and detailed field surveys. The topography of the paleoglaciers was estimated using a simple steady-state model that assumed a perfectly plastic ice rheology, reconstructing the theoretical ice profiles and obtaining the ice thickness of the glaciers during the LGM. The reconstruction of the glaciers was carried out using automated and semi-automated physically-based models, obtaining more realistic results with semi-automated models. According to our study, the paleoglaciers in the study area covered an area of 34.79 km^2 during the global LGM, with a maximum ice thickness of 366 meters in La Vega gorge, a total volume of 34.25 × 108 m^3 and a mean paleoELA of 1932 meters. Most of the ice(~82%) was in paleoglaciers facing north, and the rest was in paleoglaciers with other orientations. This emphasizes the importance of orientation in relation to glacier dynamics and ice accumulation. The results obtained in the calculation of paleoELAs during the global LGM in Gredos are average compared to the Iberian mountains of the northwest where the values were much lower, and with respect to those of the Southwest, much higher. This demonstrates the importance of the exposure of Mediterranean mountains to the humidity sources coming from the nW during the global LGM, as is the case at present.

关键词： Glacier reconstruction Paleoglacier Ice thickness Equilibrium line altitude Iberian Central System

来源：

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

Sol–gel La2O3–ZrO2 mixed oxide catalysts for biodiesel production

引用

Journal of Energy Chemistry 2018年第2期27卷 565-572页

作者： Daniela Salinas Catherine Sepúlveda néstor Escalona J.L.GFierro Gina Pecchi Departamento de Fisicoquimica. Facultad de Ciencias Quimicas Universidad de Concepcion Post Office 160-C Concepcion Chile Departamento de Quimica Facultad de Ciencias Universidad del Biobio Post Office 5-C Concepcion Chile Departamento Ingenieria Quimica y Bioprocesos Escuela de lngenieria Pontificia Universidad Catolica de Chile Avda. Vicuria Mackenna 4870 Maeul Santiago 7820436 Chile Centro de Investigacion en nanotecnolagia y Materiales Avanzados (CIEn-UC) Pontificia Universidad Catolica de Chile Post Office 306 Santiago Chile Departamento de Quimica Fisica Facultad de Quimica Pontificia Universidad Catolica de Chile Post Offce 306 Santiago Chile Instituto de Catalisis y Petroleoquimica CSIC 28049 Madrid. Espana

Different La2O3 contents（0, 1, 2, 3, and 5 wt%） were used to prepared La2O3-ZrO2 mixed oxides calcined at 600 ℃ by the sol-gel method. The catalytic activity was measured as biodiesel production from canola oil through a transesterification reaction. The characterization results indicate that the La2O3 monolayer formation and extent of basicity of m-ZrO2 have a large influence on biodiesel *** biodiesel conversion（56% at 4 h） was obtained with the 3% La2O3-ZrO2 catalyst in the presence of basic sites and the formation of a monolayer of La2O3. The decrease in the catalytic activity for 5% La2O3-ZrO2 resulted from the loss of active sites on the catalyst because of agglomeration, which was suggested by XPS and the isoelectric point. The kinetic data fit to a pseudo-first order constant, and the largest kinetic constant corresponds to 3% La2O3-ZrO2, currently the largest heterogeneous non-alkaline metal catalyst reported for a transesterification reaction.

关键词： La2O3 -ZrO2 Sol-gel Biodiesel Canola oil Transesterification

来源：

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

Relict glacial landscape in the Sierra Baguales Mountain Range(50°-51°S):evidence of glaciation dynamics and types in the eastern foothills of the southern Patagonian Andes

引用

Journal of Mountain Science 2017年第2期14卷 282-295页

作者： ARAOS.JoséMiguel LE ROUX.Jacobus Philiphus GUTIERREZ.néstor Mauricio Department of Geology FCFMUniversidad de ChilePlaza Ercilla#803SantiagoChile Department of Geography Faculty of Social Sciences.Universidad Alberto HurtadoUienfuegos#41SantiagoChile Department of Geology FCFMUniversidad de Chile.Andean Geothermal Centre of ExcellencePlaza Ereilla#803SantiagoChile

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range(SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field(SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift,which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum(LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower *** can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26m Equilibrium Line Altitude(ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio(AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.

关键词： Glacial morphology Sierra Baguales Ice sheet glaciations Alpine glaciations Middle Holocene

来源：

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

Analysis of Operating Variables in the Catalytic Purification of Butene-1 in a Trickle Bed

引用

Chinese Journal of Chemical Engineering 1998年第2期6卷 13-25页

作者： Sergio P.Bressa néstor O.Ardiaca Osvaldo M.Martinez Guillermo F.Barreto Depto.de Ing.Qca. Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-Argentina

A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this *** analysis of typical operating conditions,only the relevant phenomena are finally retained in the model *** model is then employed to analyze the effect of operating variables and catalyst selectivity in *** particular,the search for the minimum hydrogen flow rate necessary to fulfil butene-1 purityspecifications is undertaken.

关键词： selective hydrogenation butene-1 1 3-butadiene trickle bed reactor

来源：

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

A Value for Games Defined on Graphs

引用

Applied Mathematics 2024年第5期15卷 331-348页

作者： néstor Bravo Departamento de Matemá ticas Universidad de Guanajuato Guanajuato Mexico

Given a graph g=( V,A ) , we define a space of subgraphs M with the binary operation of union and the unique decomposition property into blocks. This space allows us to discuss a notion of minimal subgraphs (minimal coalitions) that are of interest for the game. Additionally, a partition of the game is defined in terms of the gain of each block, and subsequently, a solution to the game is defined based on distributing to each player (node and edge) present in each block a payment proportional to their contribution to the coalition.

关键词： Graph Theory Values for Graphs Cooperation Games Potential Function

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China's Solution to Global Governance Crisis

引用

Contemporary World 2022年第3期 35-38页

作者： néstor Restivo Working Group on China at Argentine Council for International Relations

In today’s highly globalized world, countries and regions are ever more closely intertwined with more complex relations. As COVID-19 pandemic changes international order in a profound way, the challenges facing global governance system have intensified. There is an urgent call for change. In this context, China offers a new solution to improving global governance by proposing the vision of building a community with a shared future for mankind.

关键词： intensified today profound

来源：

维普期刊数据库博看期刊

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

Monitoring hepatitis C virus treatment rates in an Opioid Treatment Program:A longitudinal study

引用

World Journal of Gastroenterology 2020年第38期26卷 5874-5883页

作者： Arantza Sanvisens Inmaculada Rivas Eva Faure néstor Espinach Anna Hernandez-Rubio Xavier Majó Joan Colom Robert Muga Department of Internal Medicine Hospital Universitari Germans Trias i PujolBadalona 08916Spain Mental Health and Addiction Service Badalona Serveis Assistencials-BSABadalona 08911Spain Department of Internal Medicine Hospital Universitari Germans Trias i PujolUniversitat Autònoma de BarcelonaBadalona 08916Spain Program on HIV STIs and Viral Hepatitis-PCAVIHV Public Health Agency of CataloniaGeneralitat de CatalunyaBarcelona 08005Spain

BACKGROUnD Direct-acting antivirals(DAAs)are recommended for the treatment of hepatitis C virus(HCV)infection in patients treated with methadone or *** To assess HCV treatment rates in an Opioid Treatment Program(OTP).METHODS This longitudinal study included 501 patients(81.4%men,median age:45 years;interquartile range:39-50 years)enrolled in an OTP between October 2015 and September *** were followed until September *** on sociodemographics,substance use,HCV infection,human immunodeficiency virus(HIV)infection and laboratory parameters were collected at *** analyzed medical records to evaluate HCV ***-Meier methods and Cox regression models were used to analyze the DAA treatment uptake and to identify treatment *** Prevalence of HCV and HIV infection was 70%and 34%,*** anti-HCV-positive(n=336)patients,47.2%,41.3%,and 31.9%used alcohol,cannabis,and cocaine,***-RnA tests were positive in 233(69.3%)*** patients(8.3%)cleared the infection,and 59/308(19.1%)had received interferon-based treatment regimens before *** 249 patients eligible,111(44.6%)received *** rates significantly increased over time from 7.8/100 person-years(p-y)(95%CI:5.0-12.3)in 2015 to 18.9/100 p-y(95%CI:11.7-30.3)in *** a multivariate analysis,patients with HIV co-infection were twice as likely to receive DAAs(HR=1.94,95%CI:1.21-3.12)than patients with HCV *** drug use was an independent risk factor for not receiving treatment against infection(HR=0.48,95%CI:0.29-0.80).COnCLUSIOn HCV treatment is evolving in patients with HCV-HIV *** drug use while in an OTP might negatively impact the readiness to treat infection.

关键词： Direct-acting antiviral agents Opioid Treatment Program Opioid agonist therapy Hepatitis C virus infection Human immunodeficiency virus infection Drug use

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effectiveness of a home-environmental intervention package and an early child development intervention on child health and development in high-altitude rural communities in the Peruvian Andes: a cluster-randomised controlled trial

引用

Infectious Diseases of Poverty 2022年第3期11卷 95-96页

作者： néstor nuño Daniel Mäusezahl Jan Hattendorf Hector Verastegui Mariela Ortiz Stella M.Hartinger Department of Public Health and Epidemiology Swiss Tropical and Public Health InstituteKreuzstrasse 2CH-4123AllschwilSwitzerland 不详

Background: Unsafe drinking water,poor sanitation and hygiene,exposure to household air pollution and low cognitive and socio-emotional stimulation are risk factors affecting children in low-and middle-income *** implemented an integrated home-environmental intervention package(IHIP),comprising a kitchen sink,hygiene education and a certified improved biomass cookstove,and an early child development(ECD)programme to improve children´s health and developmental outcomes in the rural high-altitude Andes of ***: We conducted a one-year cluster-randomised controlled trial among 317 childrennths divided into 4 arms(IHIP+ECD,IHIP,ECD,and Control)and 40 clusters(10 clusters per arm).ECD status(socio-emotional,fine and gross motor,communication,cognitive skills,and an overall performance)measured with the Peruvian Infant Development Scale and the occurrence of self-reported child diarrhoea from caretakers were primary *** outcomes included the occurrence of acute respiratory infections and the presence of thermo-tolerant faecal bacteria in drinking *** trial was powered to compare each intervention against its control arm but it did not allow pairwise comparisons among the four *** analysis followed the intention-to-treat *** the statistical analysis,we employed generalised estimating equation models with robust standard errors and an independent correlation ***: We obtained ECD information from 101 children who received the ECD intervention(individually and combined with IHIP)and 102 *** who received the ECD intervention performed better in all the domains compared to *** found differences in the overall performance(64 vs.39%,odd ratio(OR):2.8;95%confidence interval(CI):1.6–4.9)and the cognitive domain(62 vs 46%,OR:1.9;95%CI:1.1–3.5).Data analysis of child morbidity included 154 children who received the IHIP intervention(individually and combined with ECD)and 156 ***

关键词： Child development Clinical trial Diarrhoea Improved biomass cookstoves Peru WASH

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：