检索结果-南通市图书馆

Clinical Isolates of Staphylococcus aureus Show Variation in β-Lactamase Production and Are More Susceptib.e to Antib.otics Conjugated with β-Lactamase Inhib.tors

引用

Open Journal of Medical Microb.ology 2016年第4期6卷 143-149页

作者： Uzal Umar Umar Ahmed Faruk Damoroem M. Tanko mohammed b. yerima Department for b.ological Sciences Abubakar Tafawa Balewa University Bauchi Nigeria Department of Microb.ology Federal University Dutse Dutse Nigeria

β-Lactam antib.otics are a cornerstone in the treatment of b.cterial infections on account of its high therapeutic index and selective toxicity—they act b. inhib.ting the b.osynthesis of peptidoglycan, a key component in b.cterial cell wall. Ninety (90) clinical specimens ob.ained from the microb.ology unit Specialist Hospital b.uchi were screened for S. aureus, positive isolates were examined for β-Lactamase expression b. using two Penicillin G concentrations (5000 IU/ml and 25,000 IU/ml) in acidometric agar technique with phenol red as indicator, and the susceptib.lity pattern of the isolates to β-Lactam antib.otics was also determined. S. aureus prevalence of 31% (28/90) was ob.ained, of which 96% (27/28) of strains were β-Lactamase positive in the standard test, while 63% (17/27) were ab.e to hydrolyze penicillin G concentration of 25,000 IU/ml (5X the concentration in the standard test), and a strain was found to b. β-Lactamase negative. The resistance to five β-Lactams, ampicillin, cephalexin, amoxicillin, cloxacillin and flucloxaillin, were 100%, 96%, 89%, 74% and 56% respectively. When ampicillin and amoxicillin were conjugated to β-Lactamase inhib.tors sulb.ctam and clavulanic acid respectively the resistance to ampicillin decreased to 21% and to amoxicillin to 15%. The antib.otic susceptib.lity profile revealed β-Lactamase elab.ration to b. the major mechanism of resistance to the β-Lactams. β-Lactam utilization as therapeutic option would thus require the search for sensitive irreversib.e β-Lactamase inhib.tors for the β-Lactamase enzymes or agents to b.ock the release of β-Lactamase b. strains.

关键词： β-Lactamase Peptidoglycan Transpeptidation Haemolysis Resistance Antib.otics

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

Quartz dissolution in a single phase-high pH b.rea sandstone via alkaline injection

引用

Energy Geoscience 2021年第3期2卷 181-188页

作者： Ab.ullah Musa Ali mohammed yerima Kwaya Ab.b.kar Mijinyawa Department of Geology Bayero University Kano(BUK)KanoNigeria

A common assertion is that alkaline solution aids oil mob.lization b. generating in situ soap,or b. lowering interfacial tension(IFT)to ultra-low values in synergy with *** study takes a different approach that involves the alkaline dissolution of detrital quartz grains of sandstone reservoirs to create pathways for oil migration and *** dissolution via alkaline injection will result in changes in permeab.lity and *** study performed high-pH core flooding on b.rea sandstones using core displacement *** molyb.ate spectrophotometry was applied to measure the amount of dissolved *** and confining pressure variations were also *** molar concentration of NaOH varied at 0.5 M and 1.0 *** results show higher initial silica dissolution for 0.5 M NaOH(˃200mg/L)compared to 1.0 M NaOH(20 mg/L),which can b. attrib.ted to the presence of pre-existing dissolved silica and precipitates in the system prior to the first injection ***,a steady quartz dissolution rate of 0.4 mg/L/hr for 20 h was only achieved at 1.0 ***,an ab.upt drop in quartz dissolution to b.low 0 mg/L was recorded for 0.5 M NaOH after 3 h of *** higher molar concentration of injected alkaline solution,b.th confining and inlet pressures increased from 8 and 5 b.rs to 12 and 11 b.rs as a result of the increased secondary phase of(hydr)oxides or precipitates in the ***,it can b. inferred that the effect of alkaline solution on quartz dissolution is strongly dependent on molar concentration.

关键词： Alkaline injection Core flooding Dissolved silica Quartz Petroleum recovery

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

Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel comb.stion method

引用

Journal of Advanced Ceramics 2020年第2期9卷 162-172页

作者： M.A.mohammed M.b.UDAY S.IZMAN School of Mechanical Engineering Faculty of EngineeringUniversiti Teknologi Malaysia(UTM)UTM Skudai 81310JohorMalaysia Centre for Advanced Composite Materials(CACM) Institute for Vehicle Systems and EngineeringUniversiti Teknologi MalaysiaUTM Skudai 81310JohorMalaysia Department of Materials Engineering College of EngineeringUniversity of BasrahBasrahIraq

Ca3Co4O9 is a p-type semiconducting material that is well-known for its thermoelectric(TE),magnetic,electronic,and electro-optic *** this study,sol–gel autoignition was used to prepare Ca3Co4O9 at different calcination temperatures(773,873,973,and 1073 K)and time(4,6,8,10,12,and 14 h)using starch as a *** phase and microstructure of the prepared Ca3Co4O9 powder were ***–differential thermal analysis(TGA)confirms that the final weight loss occurred at 1073 K to form Ca3Co4O9 stab.e *** variab.e-pressure scanning electron microscopy(VP-SEM)images show that the size of powder particles increases from 1.15 to 1.47μm as calcination time increases from 4 to 12 h,and the size remains almost constant thereafter.A similar pattern is also ob.erved on the increment of the crystallite size and percentage of crystallinity with X-ray diffraction(XRD)*** highest crystallinity is found ab.ut 92.9%when the powder was calcinated at 1073 K for 12 and 14 h with 458 and 460Åcrystallite size,*** dispersive X-ray spectroscopy(EDS)analysis demonstrates that the calcinated powder has a high intensity of Ca,Co,and O with uniform ***-resolution transmission electron microscopy(HRTEM)images prove that there is no distinct lattice distortion defect on the crystal structure.

关键词： calcium cob.lt oxide sol-gel starch comb.stion method crystallite size crystallinity

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

Evaluation of the microstructure,thermal and mechanical properties of Cu/SiC nanocomposites fab.icated b. mechanical alloying

引用

International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 475-486页

作者： Essam b.Moustafa mohammed A.Taha Mechanical Engineering Departments Faculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia Solid State Physics Department National Research CentreEl Buhouth St.Dokki12622 GizaEgypt

Nano-sized silicon carb.de(SiC:0wt%,1wt%,2wt%,4wt%,and 8wt%)reinforced copper(Cu)matrix nanocomposites were manufactured,pressed,and sintered at 775 and 875℃in an argon atmosphere.X-ray diffraction(XRD)and scanning electron microscopy were performed to characterize the microstructural *** density,thermal expansion,mechanical,and electrical properties were *** analyses showed that with increasing SiC content,the microstrain and dislocation density increased,while the crystal size *** coefficient of thermal expansion(CTE)of the nanocomposites was less than that of the Cu *** improvement in the CTE with increasing sintering temperature may b. b.cause of densification of the ***,the mechanical properties of these nanocomposites showed noticeab.e enhancements with the addition of SiC and sintering temperatures,where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt%SiC and sintered at 875℃were 958.7 MPa and 1.07 vol%^(−1),*** electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering *** prepared Cu/SiC nanocomposites possessed good electrical conductivity,high thermal stab.lity,and excellent mechanical properties.

关键词： copper matrix nanocomposites silicon carb.de coefficient of thermal expansion elastic moduli electrical conductivity mechanical alloying

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

Geothermal Gradient and Heat Flow in the Nigeria Sector of the Chad b.sin, Nigeria

引用

Computational Water, Energy, and Environmental Engineering 2016年第2期5卷 70-78页

作者： mohammed yerima Kwaya Ewa Kurowska Ab.ullahi Suleiman Arab. Department of Geology Usmanu Danfodiyo University Sokoto Nigeria Department of Fundamental Geology University of Silesia Katowice Poland Center for Energy Research and Training Ahmadu Bello University Zaria Nigeria

Information on geothermal gradient and heat flow within the sub.urface is critical in the quest for geothermal energy exploration. In a b.d to ascertain the thermal potential of Nigeria sector of the Chad b.sin for energy generation, sub.urface temperature information from 19 oil wells, 24 water b.reholes drilled to depths b.yond 100 metres and atmospheric temperature from the Chad b.sin were utilized in calculating geothermal gradient of the area. Selected ditch cuttings from the wells were sub.ected to thermal conductivity test using Thermal Conductivity Scanner (TCS) at the Polish Geological Institute Lab.ratory in Warsaw. The terrestrial heat flow was calculated according to the Fourier’s law as a simple product of the geothermal gradient and the mean thermal conductivity. Results ob.ained indicated geothermal gradient range of 2.81 °C/100 m to 5.88 °C/100 m with an average of 3.71 °C/100 m. The thermal conductivity values from the different representative samples range from 0.58 W/m*K to 4.207 W/m*K with an average of 1.626 W/m*K. The work presented a heat flow value ranging from 45 mW/m2 to ab.ut 90 mW/m2 in the Nigerian sector of the Chad b.sin.

关键词： Geothermal Gradient Heat Flow Chad b.sin Thermal Conductivity

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

Fractographic analysis of the overload effect on fatigue crack growth in 2024-T3 and 7075-T6 Al alloys

引用

International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 83-90页

作者： A.Alb.dah b.b.chir b.uiadjra S.M.A.K.mohammed F.b.nyahia Mechanical Engineering Department College of EngineeringKing Saud UniversityP.O.Box 800Riyadh 11421Saudi Arabia LMPM Department of Mechanical EngineeringUniversity of Sidi Bel AbbesBP 89CitéBen M’hidiSidi Bel Abbes 22000Algeria Department of Mechanical and Industrial Engineering Ryerson UniversityTorontoOntario M5B 2K3Canada

The effect of single overload on the fatigue crack growth in 2024-T3 and 7075-T6 Al alloys was *** tests under constantamplitude loading with overload peak were carried out on V-notched *** analysis was used as a principal approach to explain the crack growth retardation due to the *** electron microscopy(SEM)analyses were conducted on the fractured surface of failed specimens to study the retardation *** ob.ained results show that the overload application generates a plastic zone in b.th aluminum *** generated plastic zone is three times larger in the case of 2024-T3 compared to 7075-T6,and thus,a significant crack retardation was induced for *** retardation effect due to the overload for 2024-T3 and 7075-T6 lasted for ab.ut 10 mm and 1 mm,respectively,from the point of overload application.

关键词： fatigue crack growth overload retardation fractography crack tip plasticity

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

Non-alcoholic fatty liver disease:Immunological mechanisms and current treatments

引用

World Journal of Gastroenterology 2023年第32期29卷 4831-4850页

作者： Lucy Petagine mohammed Gulrez Zariwala Vinood b.Patel Centre for Nutraceuticals School of Life SciencesUniversity of WestminsterLondon W1W6UWUnited Kingdom

Non-alcoholic fatty liver disease(NAFLD)causes significant glob.l disease b.rden and is a leading cause of *** induces a myriad of ab.rrant changes in hepatocytes at b.th the cellular and molecular *** the disease spectrum of NAFLD is widely recognised,the precise triggers for disease progression are still to b. fully ***,the propagation to cirrhosis is poorly *** some progress in terms of treatment options have b.en explored,an incomplete understanding of the hepatic cellular and molecular alterations limits their clinical *** have therefore reviewed some of the key pathways responsib.e for the pathogenesis of NAFLD such as innate and adaptative immunity,lipotoxicity and fib.ogenesis,and highlighted current trials and treatment options for NAFLD patients.

关键词： Liver Fat Inflammation Mitochondria Immune system

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

Utilization of low quality water of mountain reservoirs: a case study from Al Jab.l Al Akhdar, Oman

引用

Journal of Mountain Science 2016年第8期13卷 1423-1430页

作者： Mushtaque AHMED Reginald VICTOR mohammed JASHOUL b.S. CHOUDRI Department of Soils Water and Agricultural Engineering College of Agricultural and Marine SciencesSultan Qaboos University Department of b.ology College of ScienceSultan Qaboos University Salalah Free Zone Sultanate of Oman Center for Environmental Studies and Research Sultan Qaboos University

Al Jab.l al Akhdar(Green Mountain) in arid northern Oman has freshwater resources that had supported small communities for hundreds of years. Jab.l Akhdar receives more rainfall(300-400 mm) when compared to the desert plains. In the last few years, this region had undergone enormous changes due to rapid development. The resident and transient populations have increased and their activities exert severe stress on the water resources. There are 24 retention reservoirs in the area, b.t most are eutrophic and the nutrient loading is due to input of animal fecal matter via surface run-off. As expected, these waters contaminated with coliform b.cteria and some have pathogenic Escherichia coli. Drinking water needs of all the villages met b. groundwater extraction. b.cause of poor quality, the surface water in the reservoirs is under-utilized. A low-cost lowmaintenance treatment system designed, constructed and operated in one village to clean the reservoir water for non-drinking human use. The treatment unit improved the water quality parameters. A survey among the adult male population of the village showed their eagerness to adopt this system and use the treated reservoir water for uses other than agriculture. Estab.ishment of these treatment units in other villages should reduce the pressures on groundwater extraction.

关键词： Jab.l Akhdar Oman Reservoir Eutrophication Treatment Society

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

Entropy and Entanglement in Master Equation of Effective Hamiltonian for Jaynes-Cummings Model

引用

Communications in Theoretical Physics 2009年第4期51卷 723-728页

作者： H.A.Hessian F.A.mohammed A.-b.A.Mohamed Faculty of Science Assiut University

In this paper, we analytically solve the master equation for Jaynes-Cummings model in the dispersive regime including phase damping and the field is assumed to b. initially in a superposition of coherent states. Using an estab.ished entanglement measure b.sed on the negativity of the eigenvalues of the partially transposed density matrix we find a very strong sensitivity of the maximally generated entanglement to the amount of phase damping. Qualitatively this b.havior is also reflected in alternative entanglement measures, b.t the quantitative agreement b.tween different measures depends on the chosen noise model The phase decoherence for this model results in monotonic increase in the total entropy while the atomic sub.entropy keeps its periodic b.haviour without any effect.

关键词： entanglement phase damping master equation superposition state

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

Formab.lity of Materials with Small Tools in Incremental Forming

引用

Chinese Journal of Mechanical Engineering 2020年第4期33卷 150-158页

作者： Hongyu Wei G.Hussain X.Shi b.b.L Isidore mohammed Alkahtani Mustufa Haider Ab.di College Mechanical&Electrical Engineering Nanjing University of Aeronautics&AstronauticsNanjingPeople’s Republic of China Faculty of Mechanical Engineering GIK Institute of Engineering Sciences&TechnologyTopi 23460Pakistan College of Mechanical Engineering Shanghai University of Engineering ScienceShanghaiPeople’s Republic of China b.adenb.rg University of Technology CottbusGermany Industrial Engineering Department College of EngineeringKing Saud UniversityRiyadh 11421Saudi Arabia Advanced Manufacturing Institute King Saud UniversityRiyadh 11421Saudi Arabia

Single point incremental forming(SPIF)is an innovative sheet forming process with a high economic *** formab.lity in this process can b. maximized b. executing forming with a tool of specific small radius,regarded as threshold critical *** value has b.en reported as 2.2 mm for 1 mm thick sheet ***,with a change in the forming conditions specifically in the sheet thickness and step size,the critical radius is likely to alter due to a change in the b.nding *** main aim of the present study is to undertake this point into account and develop a relatively generic *** study is composed of experimental and numerical *** maximum wall angle(θmax)without sheet fracturing is regarded as sheet formab.lity.A numb.r of sheet materials are formed to fracture and the trends correlating formab.lity with normalized radius(i.e.,R/To where R is the tool-radius and To is the sheet thickness)are *** trends confirm that there is a critical tool-radius(Rc)that maximizes the formab.lity in ***,it is found that the critical radius is not fixed rather it shows dependence on the sheet thickness such that Rc=βTo,whereβvaries from 2.2 to 3.3 as the thickness increases from 1 mm to 3 *** critical radius,however,remains insensitive to variation in step size ranging from 0.3 mm to 0.7 *** is also ob.erved that the selection of tool with Rb.lity window not only on the higher side b.t also on the lower *** higher limit,as revealed b. the experimental and FEA results,diminishes due to excessive shearing b.cause of in-plane b.axial compression,and the lower limit reduces due to pillowing in the b.ttom of *** new tool-radius condition proposed herein study would b. helpful in maximizing the formab.lity of materials in SPIF without performing experimental trials.

关键词： Incremental forming Critical tool-radius Formab.lity curve Finite element analysis

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

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：