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Eco-Friendly Phyto-Synthesis of Silver Nanoparticles Using Jatropha Seedcake Extract

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Chinese Physics Letters 2013年第12期30卷 165-169页

作者： Anjali Bose Haresh Keharia m.P.Deshpande BRD School of Biosciences Sardar Patel MaidanVadtal RoadP.O.Box 39Satellite CampusSardar Patel UniversityVallabh Vidyanagar 388120GujaratIndia Department of Physics Sardar Patel UniversityVallabh Vidyanagar 388120GujaratIndia

Phytosynthesis of metal nanoparticles is gaining importance due to their biocompatibility,low toxicity and eco-friendly *** the present study,an aqueous extract of Jatropha seedcake(JSC)is assessed as a reducing and stabilizing agent for the synthesis of silver nanoparticles(AgNPs).The maximum reduction of silver ions occur when 1 mm AgNO_(3) solution is treated with 0.1 volume fraction of JSC extract in boiling water bath for 10 *** synthesis of AgNPs is monitored by the excitation of surface plasmon resonance using UV-vis *** AgNPs are found to be mono-dispersed,spherical with average particle size of 10.48±74 nm when analyzed by transmission electron *** selected area electron diffraction(SAED)ring pattern indicated the polycrystalline nature of the *** x-ray diffraction data further confirm the presence of characteristic(111),(200),(220),(311)and(222)diffraction planes of face centered cubic structure,and the calculated lattice parameter comes out to be 4.083Å.FTIR analysis reveals the involvement of proteins and phenols in reduction and stabilization of *** synthesized AgNPs have significant antibacterial action on both the Gram positive and negative bacteria.

关键词： silver synthesis stabilization

Dynamic Recrystallization of a Cr-Ni-mo-Cu-Ti-V Precipitation Hardenable Stainless Steel

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Journal of materials Science & Technology 2007年第6期23卷 775-778页

作者： A.momeni A.Shokuhfar S.m.Abbasi Advanced materials Research Lab Mechanical DepartmentKNT University of TechnologyTehranIran

In this research, the dynamic recrystallization （DRX） behavior of an as-cast precipitation hardenable （PH） stainless steel was investigated by conducting hot compression tests at temperatures between 950-1150℃ and under strain rates of 0.001-1 s^-1. The flow stress curves show that the DRX is responsible for flow softening during hot compression. The effects of temperature and strain rate on the strain and stress corresponding to peak point （εp and σp） of flow curve were analyzed individually. It is realized that, they increase with strain rate and decrease with temperature. The relationship between Zener-Hollomon parameter （Z） and εp was investigated and the equation of εp=4.3×10^-4^0.14 was proposed. The strain for the maximum rate of DRX （εmax） was determined under different deformation conditions. Therefore, it is realized that it increases with Z parameter and vise versa. On the basis of obtained results, the equation of εmax=9.5 × 10^-4Z0.12 was proposed.

关键词： Dynamic recrystallization Hot compression Precipitation hardening stainless steel

magnetic Properties of Nd-Fe-B Sintered magnet Powders Recovered by Yb metal Vapor Sorption

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Journal of Rare Earths 2004年第1期22卷 152-156页

作者： Horikawa T Itoh m Suzuki Shunji machida K Collaborative Research Center for Advanced Science and Technology Collaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and TechnologyCollaborative Research Center for Advanced Science and Technology Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan Osaka University Osaka 565-0871 Japan

Fine ground powders of Nd-Fe-B sintered magnet bulks (particle size=46～125 μm in diameter) were coated and alloyed with Yb metal by sorbing them. A significant recovery of the decreased magnetic properties of the ground powders (remanence B r=～0.95 T, coercivity H cj =～227 kA·m -1 and maximum energy product (BH) max=～48 8 kJ·m -3) was observed in accordance with increasing temperature up to 800 ℃. The sorbing temperature and time for Yb metal vapor were optimized and after heating at 800 ℃ for 90 min and annealing subsequently at 610 ℃ for 60 min, the B r, H cj and (BH) max values were increased to be 0.98 T, 712 kA·m -1 and 173 kJ·m -3, respectively. From the microstructural characterizations of resulting samples by using X-ray diffraction (XRD), scanning electron microscopy (SEm), and electron probe X-ray microanalyzer (EPmA), it is found that the sorbed Yb metal uniformly covers the surface and diffuses to the Nd-rich grain boundary of fine ground powders of Nd-Fe-B sintered magnet bulks forming a (Nd,Yb)Fe 2 phase.

关键词： metal materials Nd 2Fe 14B sintered magnets metal vapor sorption magnetic properties recovery rare earths

Electron Acceleration by microwave Radiation Inside a Rectangular Waveguide

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Plasma Science and Technology 2011年第3期13卷 357-361页

作者： B. F. mOHAmED A.m. GOUDA Plasma Physics Department N.R.C. Atomic Energy Authority Cairo Egypt

Electron dynamics in the fields associated with a transverse magnetic （Tm） wave propagating inside a rectangular waveguide is analytically studied. The relativistic momentum and energy equations for an electron are solved, which was injected initially along the propagation direction of the microwave. Expressions of the acceleration gradient and deflection angle are obtained. In principle, it is shown that the electron can be accelerated in this condition and there is no deflection when the electron is injected from the centre of the waveguide front. However, it is found that the acceleration gradient and deflection angle depend strongly on the parameters of the microwave （intensity, frequency, etc.） and the dimensions of the waveguide.

关键词： waveguide electron acceleration polarized microwave

DSC study on temperature memory effect of NiTi shape memory alloy

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中国有色金属学会会刊：英文版 2006年第B01期16卷 37-41页

作者： N. LIU W. m. HUANG School of mechanical and Aerospace Engineering Nanyang Technological University Singapore 639798

A systematic study on the temperature memory effect (TmE) in a polycrystalline NiTi shape memory alloy was presented. The investigation was carried out through a series of differential scanning calorimeter (DSC) tests. Two types of tests were conducted, namely single-step test and multi-step test. The influence of the step temperature on the peak/trough temperatures in the subsequent heating process and the associated energy absorption/release in the phase transformations was investigated. Using a simple theoretical model, the exact mechanism behind TmE was studied.

关键词：镍钛合金形状记忆合金温度记忆效应相转变差分扫描量热计

HIV protease:late action to prevent immune detection

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Signal Transduction and Targeted Therapy 2021年第5期6卷 1408-1409页

作者： Konstantin m.J.Sparrer Frank Kirchhoff Institute of molecular Virology Ulm University Medical CenterUlmGermany

A recent study published in Science by Wang and colleagues shows that premature activation of the HIV-1 protease leads to caspase activation and recruitment domain 8(CARD8)inflammasome-mediated pyroptosis of infected macrophages and CD4+T cells(Fig.1).These findings might help to improve approaches aiming to eliminate the latent viral reservoirs upon HIV-1 *** invading viral pathogens trigger the innate immune system and are usually rapidly controlled and eventually *** sense viral intruders via so-called pattern recognition receptors(PRRs)capable of detecting pathogen-associated molecular patterns(PAmPs)allowing discrimination between self and *** many cases,these patterns are viral nucleic acids that show pathogen-specific structures or emerge at the wrong localization in the ***,activation of PRRs by their respective ligands leads to the induction of various anti-viral signaling cascades,among them the inflammasome.

关键词： eventually action eliminate

Laboratory Generation of Solitary Waves:An Inversion Technique to Improve Available methods

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China Ocean Engineering 2014年第1期28卷 57-66页

作者： A.Romano m.Guerrini G.Bellotti 琚烈红 University of Roma Tre Via Vito Volterra 62Rome 00146Italy Nanjing Hydraulic Research Institute

Solitary waves are often used in laboratory experiments to study tsunamis propagation and interaction with coasts. However, the experimental shape of the waves may differ from the theoretical one. In this paper, a correction technique aiming at minimizing the discrepancies between the two profiles is presented. Laboratory experiments reveal their effectiveness in correcting the experimental shape of solitary waves, mainly for low nonlinearities.

关键词： tsunamis solitary waves correction technique laboratory generation

Evaluation of reliability of Coats-Redfern method for kinetic analysis of non-isothermal TGA

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中国有色金属学会会刊：英文版 2008年第1期18卷 217-221页

作者： R.Ebrahimi-Kahrizsangi m.H.Abbasi Department of Engineering Islamic Azad UniversityNajafabad branch Department of materials Engineering Isfahan University of Technology

A critical examination was made on the reliability of kinetic parameters of nonisothermal thermoanalytical rate measurement by the widely applied Coats-Redfern(CR)*** this purpose,simulated TGA curves were made for reactions with different kinetic models,including chemical,diffusion(Janders)and mixed mechanism at different heating *** results show that,for reactions controlled kinetically by one mechanism,all solid state reaction models show linear trends by use of CR method and this method can not distinct the correct reaction *** reactions with mixed mechanism,the CR method shows nonlinear trends and the reaction models and kinetic parameters can not be extracted from CR *** overall conclusion from this comparative appraisal of the characteristics of the CR approach to kinetic analysis of TGA data is that the CR approach is generally unsuitable for determination of kinetic parameters.

关键词：动态分析可靠性分析等温线金属学

Antibiotic Resistance Profile of Enterococcus faecalis and Enterococcus faecium Isolates from Urine and Pleural Fluid in Two Hospitals of Cameroon

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Open Journal of medical microbiology 2024年第1期14卷 39-49页

作者： Cécile Ingrid Djuikoue Farid Wega Grace Yemina Kombeu Cedric Seugnou Nana Christiane Possi Kiyang Lussabella Pohoko medzam Erica megane Noubissi makougoum Nellie mbianga Nkuigoua Herman Koyouo Tagne mérimé Joël Tchinda Talokou Yvonne Valérie Yolande mavoungou Ashu michel Agbor microbiology Department of the Faculty of Health Sciences of the Université des montagnes Bangangté Cameroon Faculty of medicine and Pharmaceutical Sciences University of Douala Douala Cameroon microbiology Department of the Faculty of Health Sciences of Institut Universitaire du Golf de Guinée Douala Cameroon Centre Hospitalier Dominicain St martin de Porres Yaoundé Cameroun Faculté des Sciences de la Santé Université Marien Ngouabi Brazzaville République du Congo

Enterococcus faecalis and Enterococcus faecium rank among the leading causes of nosocomial bacteremia and urinary tract infections. They often persist on hospital surfaces due to their ability to withstand adverse environmental conditions (low or high temperatures, high pH, and high salinity). The global Enterococcus faecalis-Enterococcus faecium ratio is currently shifting towards Enterococcus faecium. Enterococci present variable levels of resistance to certain families of antibiotics. This is the case for aminoglycosides, beta-lactams and cephalosporins. In 2017, WHO ranked Enterococci among priority pathogens for research and development of new antibiotics. The objective of our study was to determine the antibiotic resistance profile of Enterococcus faecalis and Enterococcus faecium isolates from urine and pleural fluid in two hospitals in Cameroon. This cross-sectional and analytic study was carried out between June to August 2023 on hospitalized and day patients in which a cytobacteriological test of urine and pleural fluid was done. The samples were inoculated on CLED Agar for urine and on Chocolate + polyvitex and blood agar (prepared from Columbia agar) for pleural fluid samples and incubated at 37℃ for 18 to 24 hours. Identification of isolates was carried out using the API 20 STREP micro gallery (Biomerieux, France) and tested for antimicrobial susceptibility. The data on socio-demographical and potential risk factors were recorded using self-administered questionnaires and data from laboratory analyses of the specimen were collected in a data capture sheet. Potential risk factors associated with the presence of Enterococci, were evaluated using the logistic regression in univariate and multivariate analysis. P value minantly females. Enterococcus spp were isolated in 27.79% of our samples with Enterococcus faecalis mostly encountered. Enterococcus spp showed a high

关键词： Enterococcus faecalis Enterococcus faecium Healthcare-Associated Infections Antimicrobial Resistance Cameroon