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Structural and micro structural studies of PbO-doped SnO_2 sensor for detection of methanol, propanol and acetone

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j.urnal of Natural Gas Chemistry 2011年第2期20卷 179-183页

作者： j. k. srivastava Preeti Pandey V. N. Mishra R. Dwivedi Center for Research in Microelectronics Department of Electronics Engineering Institute of Technology Banaras Hindu University

In the present work.the structural information of PbO-doped SnO2 thick.film sensor has been investigated with X-ray diffractometer （XRD） and scanning electron microscope （SEM）. Initially, SnO2 powder was derived using sol-gel process and was subsequently doped with PbO and ground up to nanosized particles. A suitable gas sensor structure was fabricated on 1′′×1′′ alumina substrate using thick.film technology. The necessary paste for screen printing was also developed. SEM results showed sol-gel derived powder gets more agglomerated in the thick.film form. The sensitivity of the sensor has been investigated at different temperatures （150 ？C？350 ？C） upon exposure to methanol, propanol and acetone, yielding a maximum at 250 ？C for acetone with 1 wt% PbO-doping while at 350 ？C for propanol with 3 wt% PbO-doping of the sensor. The reduction of particle size to nanometers （validated through XRD） leads to a dramatic improvement in sensitivity of sensors for the chosen organic vapors. The results also correlate well with the microstructural properties of the material and the dopant.

关键词： gas sensor nanosized SnO2 Sol-gel thick.film

Effect of the orientation of non-spherical metal nanoparticle with respect to light polarization on its transient optical response

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Nanotechnology and Precision Engineering 2023年第2期6卷 41-47页

作者： Asha Singh Himanshu srivastava Rama Chari j.j.yabalan Nano Science Laboratory Materials Science SectionRaja Ramanna Centre for Advanced TechnologyIndore 452013India Lithography and Microscopy Laboratory Synchrotrons Utilization SectionRaja Ramanna Centre for Advanced TechnologyIndore 452013India

Nanoparticles with non-spherical shapes are now being widely used for various photonic *** observe experimentally that the magnitude as well as the time dependence of the transient absorption of a colloid of silver nanoplatelets depends on the relative polarization of the pump and probe *** have been a few reports about the dependence of the transient signal magnitude on polarization,but little information is available on its temporal *** a theoretical model,we show that this observed behavior arises from the fact that the energy absorption by a non-spherical nanoparticle depends on,among other factors,the nanoparticle orientation with respect to the pump and probe polarization *** is essential to consider this when estimating nanoparticle characteristics such as carrier thermalization time,carrier–phonon scattering time,and complex polarizability from transient absorption measurements.

关键词： Ultrafast dynamics Metal Nanoparticles Transient Absorption Polarization dependence

High-yield synthesis and liquid-exfoliation of two- dimensional belt-lik. hafnium disulphide

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Nano Research 2018年第1期11卷 343-353页

作者： Harneet k.ur Sandeep Yadav Avanish k. srivastava Nidhi Singh Shyama Rath j.rg j. Schneider Om P. Sinha Ritu srivastava National Physical Laboratory Council of Scientific and Industrial Research Dr. K. S. Krishnan Road New Delhi I I O012 India Academy of Scientific and Innovative Research NPL New Delhi 110012 India Technische Universitat Darmstadt Eduard-ZintMnstitut f~r Anorganische und Physikalische Chemie 12 105 117 Alarich-Weiss-Str 12 64287 Darmstadt Germany DepartmentofPhysics andAstrophysics University of Delhi Delhi 110007 India Amity Institute of Nanotechnology Amity University UP Sector 125 Noida Uttar Pradesh 201313 India

Producing environmentally stable monolayers and few-layers of hafnium disulphide （HfS2） with a high yield to reveal its unlock.d electronic and optoelectronic applications is still a challenge. HfS2 is a layered two-dimensional material of group-IV transition metal dichalcogenides. For the first time, we demonstrate a simple and cost-effective method to grow layered belt-lik. nanocrystals of HfS2 with a notably large interlayer spacing followed by their chemical exfoliation. Various microscopic and spectroscopic techniques confirm that these as-grown crystals exfoliate into single or multiple layers in a few minutes using solvent assisted ultrasonification method in N-cyclohexyl-2- pyrrolidone. The exfoliated nanosheets of HfS2 exhibit an indirect bandgap of 1.3 eV with high stability against surface degradation. Furthermore, we demonstrate that these nanosheets hold potential for electronic applications by fabricating a field-effect transistor based on few-layered HfS2, exhibiting a field-effect mobility of 0.95 cm2/（V.s） with a high on/off current modulation ratio of 10,000 in ambient conditions. The method is scalable and has a potential significance for both academic and industrial purposes.

关键词： two-dimensionalmaterials hafnium disulphide nano-crystals liquid-phase exfoliation environment-stabili~ field-effect transistor

Efficacy and dose response of Lactiplantibacillus plantarum in diarrhea-predominant irritable bowel syndrome

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World j.urnal of Gastroenterology 2023年第28期29卷 4451-4465页

作者： Christopher j.Martoni Shalini srivastava Anders Damholt Gregory j.Leyer Clinical Development Human HealthChr.Hansen A/SHoersholm 2970Denmark Clinical Development Vedic LifesciencesMumbai 400053India Scientific Affairs Human HealthChr.Hansen A/SHoersholm 2970Denmark

BACk.ROUND Probiotics have shown promise in alleviating symptoms of diarrhea-predominant irritable bowel syndrome(IBS-D);however,the certainty of evidence is *** randomized controlled dose-ranging trials are warranted on promising single-strain *** To investigate the clinical efficacy of Lactiplantibacillus plantarum(***)Lpla33(DSM34428)in adults with *** This is a randomized,double-blind,placebo-controlled,multi-center,and doseranging *** hundred and seven adults,18-70 years of age,with IBS-D,according to Rome IV criteria,were allocated(1:1:1)to receive placebo or *** Lpla33 at 1×10^(9)(1B)or 1×10^(10)(10B)colony-forming units/d over an 8-wk.intervention *** primary outcome was the change in IBS severity scoring system(IBS-SSS)total score after 8 wk.while secondary and exploratory outcomes included abdominal pain severity,IBS related quality of life,stool and microbial profile,and perceived *** IBS-SSS was significantly reduced,after 8 wk.in participants receiving *** 1B(-128.45±83.30;P<0.001)and *** 10B(-156.77±99.06;P<0.001),compared to placebo(-58.82±74.75).Further,a dose-ranging effect was observed,with a greater absolute reduction in the *** 10B group(P<0.05).A reduction in sub-scores related to abdominal pain,abdominal distension,bowel habits,and quality of life was observed in both *** groups compared to placebo(P<0.001).Further,62.5%and 88.4%of participants administered *** 1B and 10B,respectively,were classified as stool consistency responders based on a reduction in diarrheal stool form,as compared to 26.3%in the placebo group(P<0.001).In contrast,no significant shifts were observed in microbial *** *** Lpla33(DSM34428)is well tolerated and improves IBS symptom severity with a dose-ranging effect and a corresponding normalization of bowel habits in adults with IBS-D.

关键词： Randomized clinical trial Diarrhea-predominant irritable bowel syndrome Microbiome Probiotic Lactiplantibacillus plantarum

Detection and Classification of Potential Caves on the Flank.of Elysium Mons,Mars

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Research in Astronomy and Astrophysics 2022年第6期22卷 81-90页

作者： Ravi Sharma Neeraj.srivastava j.j.T.University Jhunjhunu.Rajasthan 333001India Planetary Science Division Physical Research LaboratoryAhmedabad 380009India

Martian caves have revived interest in the field of subsurface exploration because they are the potential destinations for future human habitats and astrobiological *** are many pits on Mars,but some of them look.lik. collapsed cave *** special pits are formed by the collapse of surface materials into the subsurface void *** signature of life is probable in a subsurface cave on Mars as the subsurface environment can protect life from the harsh and dangerous radiation environment of the *** a cave,there may be an abundance of minerals,fluids,and other k.y ***,locating the access point of the subsurface cave is essential and crucial for formulating plans for robotic/human explorations of the Red Planet,*** have used remote sensing data from Mars Reconnaissance Orbiter(MRO;NASA),Mars Global Surveyor(MGS;NASA),and Mars Odyssey(NASA)for identifying,mapping,and classifying selected special pit candidates on the flank.of Elysium Mons,Mars.A total of 32 special pit candidates has been identified and classified based upon morphology and geological *** of these,26 are newly discovered *** thermal behavior of 23 special pit candidates confirms that the special pits are radiating heat energy at nighttime,similar to potential ***,cave entrances have been detected in nine candidates using data from the Hi RISE camera onboard *** sites could be important destinations for future robotic/human exploration and the search for life on Mars.

关键词： planets and satellites individual(Mars)-planets and satellites surfaces-planets and satellites general

Models and form factors for stand volume estimation in natural forest ecosystems: a case study of k.tarniaghat Wildlife Sanctuary (k.WS), Bahraich District, India

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j.urnal of Forestry Research 2013年第2期24卷 217-226页

作者： V. A. j.Adek.nle k. N. Nair A. k. srivastava N. k. Singh Federal University of Technology Dept of Forestry & Wood Technology National Botanical Research Institute (Council for Scientific & Industrial Research) Plant Diversity Systematics & Herbarium Division Rana Pratap Marg Department of Forests Sidhauli Forest Division

In view of the difficulties in stand volume estimation in natural forests, we derived real form factors and models for volume estimation in these types of forest ecosystems, using k.tarniaghat Wildlife Sanctuary as a case study. Tree growth data were obtained for all trees （dbh 〉10 cm） in 4 plots （25 × 25 m） randomly located in each of three strata selected in the forest. The form factor calculated for the stand was 0.42 and a range of 0.42 0.57 was estimated for selected species （density 〉10）. The parameters of model variables were consistent with general growth trends of trees and each was statistically significant. There was no significant difference （p〉0.05） between the observed and predicted volumes for all models and there was very high correlation between observed and predicted volumes. The output of the performance statistics and the logical signs of the regression coefficients of the models demonstrated that they are useful for volume estimation with minimal error. Plotting the biases with respect to considerable regressor variables showed no meaningful and evident trend of bias values along with the independent variables. This showed that the models did not violate regression assumptions and there were no heteroscedacity or multiculnarity problems. We recommend use of the form factors and models in this ecosystem and in similar ones for stand and tree volume estimation.

关键词： natural forest tree volume Estimation biodiversity tree height forest inventory

Movement Patterns of Metallic Particles in a Single Phase Gas Insulated Busduct with Superimposed Lightning and Switching Impulses

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高电压技术 2008年第12期34卷 2642-2647页

作者： M. Venu Gopala Rao j. Amarnath G.V. Nagesh k.mar S. k.mak.haiah k. D. srivastava QIS College of Engineering and Technology Ongole 523272 Andhra Pradesh India College of Engineering Jawaharlal Nehru Technological University Kuktrtpally Hyderabad 500085 Andhra Pradesh India Vignan's Institute of Information Technology Visakhapatnam 530046 Andhra Pradesh India C. V. R. College of Engineering Hyderabad Andhra Pradesh India University of British Colombia Vancouver B. C. V6T 1Z4 Canada

Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus,lik. circuit break.rs,transformers,insulators *** it is necessary for the GIS also to withstand such voltages without break.own of *** system has to be tested under these *** the GIS system operates on power *** Impulse Voltage of 1050 k. and Switching Impulse Voltage of 750 k. superimposed on Power frequency voltages of 75 k.,100 k. and 132 k. are applied to Single Phase Gas Insulated Busduct and the maximum movement of Aluminum,Copper and Silver particles is *** movement patterns are also determined with and without Monte Carlo Simulation for movement of particle in axial and radial *** results show that there is a sudden j.mp in the movement at the application of impulse on sine *** is because of high magnitude voltage of 1050 k. during 1.2/50 μ*** movement patterns of reduced maximum movement is observed for Switching Impulse superimposed on sine *** results are presented and analyzed.

关键词：重复雷击金属微粒运动形态气相绝缘站粒子污染物

Environmental Exposure to Lead as a Risk.for Prostate Cancer

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Biomedical and Environmental Sciences 2002年第4期15卷 298-305页

作者： M．k.j.SIDDIQUI S．srivastava 等 IndustialToxicologyReserachCentre PostBoxNo.80.M.G.Marg.Lucknow226－001India Dr RMLAvadhUniversityFaizabad－224001India

Obj.ctive To evaluate the possible role of environmental exposure to lead as a risk.factor for prostate pathology in patients suffering from prostate cancer (PCA) and benign prostate hyperplasia (BPH). Methods Blood lead (BPb) level was determined in PCA and BPH cases using a graphite furnace Atomic Absorption Spectrophotometer and compared with those in a control group living in the similar socioeconomic environment. Results BPb was significantly higher in PCA and BPH cases than in normals (Pj.sting for age as a possible confounders. However, positive association between blood lead and TEARS was relatively higher in PCA patients (r=0.77, Pk.factor for prostate cancer and/or benign prostate hyperplasia possibly through generation of reactive oxygen species and/or reducing the level of zinc which acts as a cellular growth protector.

关键词： Benign prostate hyperplasia Prostate cancer Blood lead Atomic Absorption Spectrophotometer

Oncogenic BRAF^(V600E) induces microglial proliferation through extracellular signal-regulated k.nase and neuronal death through c-j.n N-terminal k.nase

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Neural Regeneration Research 2023年第7期18卷 1613-1622页

作者： Qing Ye Pranay srivastava Nasser Al-k.wari Xiqun Chen Department of Neurology Massachusetts General HospitalHarvard Medical SchoolCharlestownMAUSA Department of Neurology Longhua HospitalShanghai University of Traditional Chinese MedicineShanghaiChina Aligning Science Across Park.nson’s(ASAP)Collaborative Research Network Chevy ChaseMDUSA

Activating V600E in v-Raf murine sarcoma viral oncogene homolog B(BRAF)is a common driver mutation in cancers of multiple tissue origins,including melanoma and ***^(V600E) has also been implicated in *** present study aims to characterize BRAF^(V600E) during cell death and proliferation of three maj.r cell types of the central nervous system:neurons,astrocytes,and *** primary cultures(primary cortical mixed culture)and cell lines of glial cells(BV2)and neurons(SH-SY5Y)were ***^(V600E) and BRAF^(WT) expression was mediated by lentivirus or *** of downstream effectors(extracellular signal-regulated k.nase 1/2 and j.k./2)were achieved by *** astrocytes and microglia,BRAF^(V600E) induces cell proliferation,and the proliferative effect in microglia is mediated by activated extracellular signal-regulated k.nase,but not c-j.n N-terminal *** medium from BRAF^(V600E)-expressing microglia induced neuronal *** neuronal cells,BRAF^(V600E) directly induces neuronal death,through c-j.n N-terminal k.nase but not extracellular signal-regulated *** further show that BRAF-related genes are enriched in pathways in patients with Park.nson’s *** study identifies distinct consequences mediated by distinct downstream effectors in dividing glial cells and in neurons following the same BRAF mutational activation and a causal link.between BRAF-activated microglia and neuronal cell death that does not require physical *** provides insight into a possibly important role of BRAF in neurodegeneration as a result of either dysregulated BRAF in neurons or its impact on glial cells.

关键词： astrocytes cell death cell proliferation inflammation microglia mutation neurons v-Raf murine sarcoma viral oncogene homolog B(BRAF)