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Development of Cu-Exfoliated Graphite Nanoplatelets (xGnP) Metal Matrix Composite by Powder Metallurgy Route

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Graphene 2015年第4期4卷 91-111页

作者： Syed Nasimul Alam Lailesh Kumar nidhi Sharma Metallurgical and Materials Engineering Department National Institute of Technology Rourkela Rourkela India

In the present investigation the possibility of using exfoliated graphite nanoplatelets (xGnP) as reinforcement in order to enhance the mechanical properties of Cu-based metal matrix composites is explored. Cu-based metal matrix composites reinforced with different amounts of xGnP were fabricated by powder metallurgy route. The microstructure, sliding wear behaviour and mechanical properties of the Cu-xGnP composites were investigated. xGnP has been synthesized from the graphite intercalation compounds (GIC) through rapid evaporation of the intercalant at an elevated temperature. The thermally exfoliated graphite was later sonicated for a period of 5 h in acetone in order to achieve further exfoliation. The xGnP synthesized was characterized using SEM, HRTEM, X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy. The Cu and xGnP powder mixtures were consolidated under a load of 565 MPa followed by sintering at 850°C for 2 h in inert atmosphere. Cu-1, 2, 3 and 5 wt% xGnP composites were developed. Results of the wear test show that there is a significant improvement in the wear resistance of the composites up to addition of 2 wt% of xGnP. Hardness, tensile strength and strain at failure of the various Cu-xGnP composites also show improvement upto the addition of 2 wt% xGnP beyond which there is a decrease in these properties. The density of the composites decreases with the addition of higher wt% of xGnP although addition of higher wt% of xGnP leads to higher sinterability and densification of the composites, resulting in higher relative density values. The nature of fracture in the pure Cu as well as the various Cu-xGnP composites was found to be ductile. Nanoplatelets of graphite were found firmly embedded in the Cu matrix in case of Cu-xGnP composites containing low wt% of xGnP.

关键词： Powder Metallurgy Exfoliated Graphite Nanoplatelets (xGnP) Cu-Based Metal Matrix Composite Sliding Wear

Delineating the role of phytocompounds against anti-bacterial drug resistance–An update

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BIOCELL 2021年第6期45卷 1465-1477页

作者： REKHA GAHTORI MOSLEH MOHAMMAD ABOMUGHAID nidhi NEGI SARAVANAN KRISHNAN SUGAPRIYA DHANASEKARAN SOUMYA PANDIT KANU PRIYA DILLIP KUMAR BISHI RAM PRASAD PIYUSH KUMAR GUPTA Department of Biotechnology Sir J.C.Bose Technical CampusKumaun UniversityNainitalIndia Department of Medical Laboratory Sciences University of BishaBishaSaudi Arabia Department of Chemistry Kumaun UniversityNainitalIndia Dhanvantari Nano Ayushadi Pvt. Ltd.ChennaiIndia Department of Medical Laboratory Sciences(Pathology) College of Applied Medical SciencesPrince Sattam Bin Abdulaziz UniversityRiyadhSaudi Arabia Department of Life Sciences School of Basic Sciences and ResearchSharda UniversityGreater NoidaIndia Department of Biotechnology Rama Devi Women’s UniversityBhubaneswarIndia Department of Botany Mahatma Gandhi Central UniversityMotihariIndia

Antibacterial resistance developed by bacteria due to the unlimited use of antibiotics has posed a challenge for human *** kind of problem is not limited to India only,but it is a global ***,many treatments and medicines for bacterial diseases have been ***,they possess some ***,the alternative medicine has been used to target the drug resistant mechanisms and such medicines have less side effects which is becoming *** products have traditionally or historically been of importance for the development of antibacterial agents and are also known to overcome bacterial drug resistance by directly targeting the drug resistance mechanisms in *** recent years,researchers have also focused on new drug discovery from plant-based *** have looked on various phytocompounds as antibacterial *** the current review,we report various classes of secondary metabolites such as phenolic compounds,flavonoids,alkaloids,saponins,terpenes,quinones,and some essential oils that have been used as an antibacterial *** addition,we also discuss several mechanisms behind bacterial multi-drug resistance that are used during bacterial pathogenesis.

关键词： Drug-resistance Phytocompounds Antibacterial Mechanisms Medicinal plants Natural products

Amperometric Determination of Serum Cholesterol with Pencil Graphite Rod

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American Journal of Analytical Chemistry 2010年第2期1卷 41-46页

作者： nidhi Chauhan Jagriti Narang Chandra S. Pundir 不详

A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?

关键词： Cholesterol Cholesterol Oxidase Pencil Graphite Enzyme Electrode Serum Amperometric Biosensor

Application of Single Scan Differential Scanning Calorimetry Technique for Determination of Kinetic Parameters of Crystallisation in Se-Sb-Ag

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Journal of Crystallization Process and Technology 2019年第1期9卷 1-11页

作者： nidhi Yaduvanshi Deepak Kumar Nikhil Rastogi Ashok Kumar Department of Physics JSS Academy of Technical Education Noida India Department of Physics IFTM University Moradabad India Department of Physics Harcourt Butler Technical University Kanpur India

A single scan has been performed in Differential Scanning Calorimetry (DSC) at a heating rate of 15oC/min under non-isothermal conditions to investigate the crystallization kinetics of glassy Se90Sb10-xAgx alloys (where x = 2, 4, 6, 8). For this purpose, Handerson’s theory based on non-isothermal method for thermal analysis of single-scan DSC data has been used. The activation energy of crystallization and order parameter has been determined and composition dependence of these parameters has been discussed.

关键词： Differential Scanning Calorimetry Crystallization Order Parameter

Study of Bacterial Diversity of Mangroves Rhizosphere

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Open Journal of Marine Science 2016年第1期6卷 23-31页

作者： nidhi Sakhia Sunil Prajapati Vikram Shetty Shreyas Bhatt Anasuya Bhadalkar Marine Bio Resource Centre (MBRC) Jamnagar India Department of Life Sciences Hemchandracharya North Gujarat University Patan Nepal

Microbial diversity has been an important facet of scientific research, since microbes promise a plethora of biomolecules which are otherwise not found in nature. Microbes are subjected to high level of competition for survival in the environment, and hence develop mechanisms of defense. The biomolecules produced by these microbes as part of their defense or survival mechanism, are of importance for human and animal drugs and many other industrial and environmental applications. The marine counterparts of these terrestrial microbes have yet higher potential, since the marine environment has higher biotic and abiotic stresses, leading to new molecule discovery. In the current study, a bacterial diversity study of the culturable bacteria of the mangrove rhizosphere of Avicennia marina has been undertaken, to understand the flora diversity. Mangroves are unique ecosystems which are under a combination of marine and terrestrial influence. Mangroves are seaward, inland and also found in creek areas. This diversity in their habitat, leads them to produce variable root exudates, which support the growth of different types of organisms. This study has revealed that certain species are dominant in these ecosystems irrespective of the biotic and abiotic stresses, whereas certain species appear only at neutral pH. The study will help select organisms for further biomolecule discovery programs, based on their environment of isolation and other growth parameters.

关键词： Rhizosphere Mangroves Bacteria Microbial Diversity 16S rRNA Sequencing

Evaluation of intratesticular chlorhexidine gluconate for chemical contraception in dogs

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Asian pacific Journal of Reproduction 2022年第5期11卷 231-235页

作者： Aeknath Virendra Om Prakash Shrivastava Satya nidhi Shukla Manish Kumar Shukla Nitin Kumar Bajaj Afroza Khanam Firdous Ahmad Khan Department of Animal Reproduction Gynecology and ObstetricsNanaji Deshmukh Veterinary Science UniversityJabalpur482001Madhya PradeshIndia Department of Animal Reproduction Gynecology and ObstetricsSardar Vallabhbhai Patel UniversityMeerut250110Uttar PradeshIndia Department of Large Animal Medicine and Surgery School of Veterinary MedicineSt.George’s UniversityTrue BlueGrenadaWest Indies

Objective:To investigate the contraceptive effect of intratesticular injection of chlorhexidine gluconate in dogs and compare it with that of zinc gluconate neutralized with ***:Twenty-four sexually mature male mongrel dogs were randomly divided by replicate into four groups(n=6 per group).GroupⅡreceived intra-testicular injection of 2 mL zinc gluconate(10 mg/mL)neutralized with ***Ⅱreceived intratesticular injection of 2 mL chlorhexidine gluconate(5%w/v).GroupⅢreceived intratesticular injection of 2 mL chlorhexidine gluconate(4%w/v).GroupⅣdid not receive any treatment and served as the control *** morphometry was conducted on day 0,7,15 and 30 after *** was collected and evaluated on day 0 and *** were analyzed using repeated measures analysis of ***:There was no difference in the mean values of various parameters between dogs treated with zinc gluconate and those treated with chlorhexidine gluconate at any of the time *** dogs treated with zinc gluconate or chlorhexidine gluconate,there was a significant increase in the testicular morphometric parameters on day 7 followed by a significant reduction thereafter(day 15 and 30).In contrast,there was no change in any of the parameters in the control untreated dogs during the course of the *** to the pre-treatment values,the mean scrotal circumference and the mean paired testicular volume and testicular weight on day 30 were significantly lower in the treated *** samples collected on day 30 from treated dogs were found to be azoospermic,whereas no change in semen quality was observed in the control untreated ***:Intratesticular injection of chlorhexidine gluconate(5%w/v and 4%w/v)is equally as effective as zinc gluconate neutralized with arginine for chemical contraception in dogs.

关键词： Canine Contraception Zinc gluconate Chlorhexidine gluconate Morphometry

Outbreak of Salmonella Typhi enteric fever in sub-urban area of North India:A public health perspective

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Asian Pacific Journal of Tropical Medicine 2013年第2期6卷 167-168页

作者： nidhi Singla Neha Bansal Varsha Gupta Jagdish Chander Department of Microbiology Government Medical College HospitalChandigarh160030India

Outbreaks of enteric fever are a major health concern not only due to significant human morbidity and mortality but also fear of spread of multidrug resistant *** report an outbreak of enteric fever caused by Salmonella enterica serotype Typhi in a suburban area,in city Chandigarh of North ***-seven strains of *** were isolated from blood cultures over a period of two weeks with 18 of these 27 patients residing in the same *** cases were in the age group 5-14 years(10 patients,55.5%) while 4(22.2%) cases were children under 5 *** the strains showed similar resistogram being resistant to ampicillin and nalidixic acid,intermediate to ciprofloxacin and sensitive to chloramphenicol,ceftriaxone,cefotaxime,cotrimoxazole and azithromycin on disc diffusion *** inhibitory concentration of ciprofloxacin was determined by agar dilution method and was found to be raised(≥2μg/mL).This nalidixic acid resistant *** outbreak report warrants the necessity of implementing stringent sanitation practices in public health interest.

关键词： Enteric fever Fluoroquinolones Outbreak Salmonella

Co-positivity of anti-dengue virus and anti-Japanese encephalitis virus IgM in endemic area:co-infection or cross reactivity?

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Asian Pacific Journal of Tropical Medicine 2014年第2期7卷 124-129页

作者： Kaleshwar Prasad Singh Gitika Mishra Parul Jain nidhi Pandey Rachna Nagar Shikha Gupta Shantanu Prakash Om Prakash Danish Nasar Khan Sakshi Shrivastav Desh Deepak Singh Amita Jain Department of Microbiology K.G.Medical University

Objective:To report high co-positivity of anti-dengue virus(DV)and anti-Japanese encephalitis virus(JEV)IgM in an area endemic for both the viruses and to discuss the possibilities of ***:Serum samples from the patients who presented with fever,suspected central nervous system infection and thrombocytopenia,were tested for anti-DV IgM and antiJEV IgM *** reverse transcriptase polymerase chain reaction was done for detection of DV RNA and JEV ***:Of 1 410 patient sera tested for anti-DV and antiJEV antibodies,129(9.14%)were co-positive for *** co-positivity was observed only in those months when anli-JEV IgM positivily was *** of both anli-DV IgM and anti-JEV IgM were high in most of the co-positive *** these 129 co-positive cases,76 were lesled by conventional reverse Iranscriplase polymerase chain reaction for both flaviviruses,of which eight cases were co-positive for DV and ***:Co-infection with more than one fluvivirus species can occur in hyperendemic areas.

关键词： Co-infection Co-circulation Dengue virus IgM Japanese encephalitis virus Reverse transcriptase polymerase chain reaction

The Effect of Compositional Variation on Physical Properties of Te9Se72Ge19-XSbx(X = 8, 9, 10, 11, 12) Glassy Material

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New Journal of Glass and Ceramics 2013年第3期3卷 91-98页

作者： Anant Vidya nidhi Vivek Modgil V. S. Rangra Department of Physics Centre of Excellence Government Degree College Sanjauli Shimla India Department of Physics Himachal Pradesh University Shimla India

The quaternary chalcogenide glass Te9Se72Ge19-xSbx (x = 8, 9, 10, 11, 12) has been prepared by the melt quench technique. The material fragility increases due to decrease in degree of cross linking in glass matrix as the Sb content increases. The heat of atomization decreases due to lower value of heat of atomization of antimony. The glass transition temperature is calculated by Tichy-Ticha and Lankhorst approaches. The glass seems to have high value of glass transition temperature as per theoretical calculations and is monotonically decreasing with increasing Sb content because increasing concentration of Sb reduces the cohesive energy and mean bond energy of the material.

关键词： Quaternary Chalcogenide Glass Heat of Atomization Mean Bond Energy Glass Transition Temperature