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Friction 2021年第1期9卷 41-60页

作者： Deepak.k.PRAJAPATI Mayank.tiwari Department of Mechanical Engineering Indian Institute of TechnologyPatna 801103India

Dry wear experiments provide an insight detail on how severely contacting surfaces change under unlubricated sliding condition. The theory of dry sliding wear is used for understanding mixed-lubrication regime in which asperity interactions play a significant role in controlling of the friction coefficient(f). The purpose of this work.is to study the tribological behavior of AISI 304 steel in contact with AISI 52100 steel during wear. Both materials are used in rolling element bearings commanly. Experiments are carried out using a pin-on-disc tribometer under dry friction condition. The areal(three dimensional, 3D) topography parameters are measured using a 3D white light interferometer(WLI) with a 10× objective. After wear tests, wear mechanisms are analyzed utilizing scanning electron microscope(SEM). Factorial design with custom response surface design(C-RSD) is used to study the mutual effect of load and speed on response variables such as f and topography parameters. It is observed that the root mean square roughness(S_(q)) decreases with an increase in sliding time. Within the range of sliding time, S_(q) decreases with an increase in the normal load. Within the range of sliding speed and normal load, it is found that S_(q), mean summit curvature(S_(sc)), and root mean square slope(S_(dq)) are positively correlated with f. Whereas, negative correlation is found between f and correlation length(Sal), mean summit radius(R), and core roughness depth(S_(k.).

关键词： friction coefficient(f) areal topography parameters factorial design non-contact optical profiler scanning electron microscope(SEM)

Overexpression of P-glycoprotein induces acquired resistance to imatinib in chronic myelogenous leuk.mia cells

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Chinese Journal of Cancer 2012年第2期31卷 110-118页

作者： Amit k.tiwari Hsiang-Chun Wu Department of Pharmacology and Systems Therapeutics Mount Sinai School of MedicineNew YorkNY 10029USA Department of Pharmaceutical Sciences College of Pharmacy and Allied Health ProfessionsSt.John's UniversityQueensNY 11439USA

Imatinib,a break.oint cluster region(BCR)-Abelson murine leuk.mia(ABL) tyrosine k.nase inhibitor(Tk.),has revolutionized the treatment of chronic myelogenous leuk.mia(CML).However,development of multidrug resistance(MDR) limits the use of imatinib.In the present study,we aimed to investigate the mechanisms of cellular resistance to imatinib in CML.Therefore,we established an imatinib-resistant human CML cell line(k.62-imatinib) through a stepwise selection process.While characterizing the phenotype of these cells,we found that k.62-imatinib cells were 124.6-fold more resistant to imatinib than parental k.62 cells.In addition,these cells were cross-resistant to second-and third-generation BCR-ABL Tk.s.Western blot analysis and reverse transcription-polymerase chain reaction(RT-PCR) demonstrated that P-glycoprotein(P-gp) and MDR1 mRNA levels were increased in k.62-imatinib cells.In addition,accumulation of [14C]6-mercaptopurine(6-MP) was decreased,whereas the ATP-dependent efflux of [14C]6-MP and [3H]methotrexate transport were increased in k.62-imatinib cells.These data suggest that the overexpression of P-gp may play a crucial role in acquired resistance to imatinib in CML k.62-imatinib cells.

关键词：慢性粒细胞白血病白血病细胞 P-糖蛋白多药耐药过度表达 k.62细胞酪氨酸激酶抑制剂诱导

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Journal of Ocean Engineering and Science 2023年第2期8卷 111-123页

作者： Raj k.mar Ravi Shank.r Verma Atul k.mar tiwari Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur222003India Department of Mathematics Motihari College of EngineeringMotihari845401BiharIndia

This work.is devoted to get a new family of analytical solutions of the(2+1)-coupled dispersive long wave equations propagating in an infinitely long channel with constant depth,and can be observed in an open sea or in wide channels.The solutions are obtained by using the invariance property of the similarity transformations method via one-parameter Lie group theory.The repeated use of the similarity transformations method can transform the system of PDEs into system of ODEs.Under adequate restrictions,the reduced system of ODEs is solved.Numerical simulation is performed to describe the solutions in a physically meaningful way.The profiles of the solutions are simulated by tak.ng an appropriate choice of functions and constants involved therein.In each animation,a frame for dominated behavior is captured.They exhibit elastic multisolitons,single soliton,doubly solitons,stationary,k.nk.and parabolic nature.The results are significant since these have confirmed some of the established results of S.k.mar et al.(2020)and k.Sharma et al.(2020).Some of their solutions can be deduced from the results derived in this work.Other results in the existing literature are different from those in this work.

关键词： Dispersive long wave equations Solitons Invariants Lie-group Similarity solutions

High thermoelectric properties with low thermal conductivity due to the porous structure induced by the dendritic branching in n-type PbS

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Nano Research 2022年第5期15卷 4739-4746页

作者： Zhenyu Zhu Janak.tiwari Tianli Feng Zhan Shi Yue Lou Biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Department of Mechanical Engineering The University of UtahSalt Lake CityUT 84112USA State k.y Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China State k.y Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210000China

PbS-based thermoelectric materials have attracted extensive attention in recent years for the advantages of earth abundancy and low cost,which is considered to be a substitute for traditional PbTe material.However,their high thermal conductivity restricts its development.Hence,in order to improve their thermoelectric performance from reducing the thermal conductivity,a k.nd of dendritic PbS with controlled crystal grain and morphology are obtained by solution synthesis.By adjusting the amount of surfactant(CTAB),the specific formation process of dendrites is regulated.After sintering,the dendritic PbS nanoparticles are easy to form porous structure due to the overlapping and staggered arrangement of dendritic branches.For comparison,we also prepare a k.nd of regular octahedral PbS and a dense pack.ng arrangement is formed because of the integrity of the octahedral structure.DFT-based Boltzmann transport equation is used to prove the crucial role of porous structure in scattering phonon.Finally,a maximum zT=1.0 at 773 k.in n-type PbS is obtained,which still k.ep a high-speed growth and is expected to get higher zT value in a higher temperature region.Our work.may shed light to other thermoelectric materials from the formation of porous structure to reduce the thermal conductivity.

关键词： thermoelectric materials lead sulfide solution synthesis porous structure

IoT & AI Enabled Three-Phase Secure and Non-Invasive COVID 19 Diagnosis System

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Computers, Materials & Continua 2022年第4期71卷 423-438页

作者： Anurag Jain k.sum Yadav Hadeel Fahad Alharbi Shamik.tiwari Virtualization Department School of Computer ScienceUniversity of Petroleum and Energy StudiesDehradun248007UttarakhandIndia College of Computer Science and Engineering University of Ha’ilHa’ilKingdom of Saudi Arabia

Corona is a viral disease that has tak.n the form of an epidemic and is causing havoc worldwide after its first appearance in the Wuhan state of China in December 2019.Due to the similarity in initial symptoms with viral fever,it is challenging to identify this virus initially.Non-detection of this virus at the early stage results in the death of the patient.Developing and densely populated countries face a scarcity of resources lik. hospitals,ventilators,oxygen,and healthcare work.rs.Technologies lik. the Internet of Things(IoT)and artificial intelligence can play a vital role in diagnosing the COVID-19 virus at an early stage.To minimize the spread of the pandemic,IoT-enabled devices can be used to collect patient’s data remotely in a secure manner.Collected data can be analyzed through a deep learning model to detect the presence of the COVID-19 virus.In this work.the authors have proposed a three-phase model to diagnose covid-19 by incorporating a chatbot,IoT,and deep learning technology.In phase one,an artificially assisted chatbot can guide an individual by ask.ng about some common symptoms.In case of detection of even a single sign,the second phase of diagnosis can be considered,consisting of using a thermal scanner and pulse oximeter.In case of high temperature and low oxygen saturation levels,the third phase of diagnosis will be recommended,where chest radiography images can be analyzed through an AI-based model to diagnose the presence of the COVID-19 virus in the human body.The proposed model reduces human intervention through chatbot-based initial screening,sensor-based IoT devices,and deep learning-based X-ray analysis.It also helps in reducing the mortality rate by detecting the presence of the COVID-19 virus at an early stage.

关键词： COVID-19 internet of things deep learning chatbot X-ray capsule network convolutional neural network

Decadal trends in precipitable water vapor over the Indus River Basin using ERA5 reanalysis data

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Journal of Mountain Science 2023年第10期20卷 2928-2945页

作者： Seema RANI Jyotsna SINGH Subhash SINGH Purushottam tiwari Suraj MAL Department of Geography Institute of ScienceBanaras Hindu UniversityUttar Pradesh 221005India Department of Geography Shaheed Bhagat Singh CollegeUniversity of DelhiNew Delhi 110017India Center for the Study of Regional Development Jawaharlal Nehru UniversityNew DelhiDelhi 11oo6zIndia

Precipitable Water Vapor(PWV)constitutes a pivotal parameter within the domains of atmospheric science,and remote sensing due to its profound influence on Earth’s climate dynamics and weather patterns.It exerts a significant impact on atmospheric stability absorption and emission of radiation,thus engendering alterations in the Earth’s radiative equilibrium.As such,precise quantification of PWV holds the potential to enhance weather prognostication and fortify preparedness against severe meteorological phenomena.This study aimed to elucidate the spatial and temporal changes in seasonal and annual PWV across the Indus River Basin and its sub-basins using ERA5 reanalysis datasets.The present study used ERA5 PWV(entire atmospheric column),air temperature at 2 m(t2m)and 500 hPa(T_500hPa),evapotranspiration,and total cloud cover data from 1960 to 2021.Theil Sen slope estimator and Mann-k.ndall test were used for trend analysis.Correlation and multiple regression methods were used to understand the association of PWV with other factors.The findings have unveiled the highest increase in mean PWV during the monsoon(0.40 mm/decade),followed by premonsoon(0.37 mm/decade),post-monsoon(0.27 mm/decade),and winter(0.19 mm/decade)throughout the study period.Additionally,the mean PWV exhibited the most pronounced positive trend in the sub-basin Lower Indus(LI),followed by Panjnad(P),k.bul(k.,and Upper Indus(UI)across all seasons,except winter.Annual PWV has also risen in the Indus basin and its sub-basins over the last six decades.PWV exhibits a consistent upward trend up to an elevation of 3500 m within the basin which is most pronounced during the monsoon season,followed by the pre-monsoon.The escalating PWV within the basin is reasonably ascribed to increasing air temperatures,augmented evapotranspiration,and heightened cloud cover.These findings hold potential utility for pertinent authorities engaged in water resource management and planning.

关键词： Himalaya Precipitable Water Vapor Indus River Basin Atmosphere Climate Change ERA5 Reanalysis data

Efficacy and safety of pharmacotherapeutic interventions used in visceral leishmaniasis clinical trials:A systematic review and network.meta-analysis

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Asian Pacific Journal of Tropical Medicine 2022年第8期15卷 343-353,I0001-I0010页

作者： Aamir Bashir Gautam Sahu Ishfaq Rashid Pramil tiwari Department of Pharmacy Practice National Institute of Pharmaceutical Education and ResearchS.A.S.Nagar Mohali160062PunjabIndia

Objective:To compare the efficacy and safety outcomes of different antileishmanial agents used in visceral leishmaniasis clinical trials.Methods:A systematic literature search in PubMed/MEDLINE,EMBASE,Cochrane,and Google Scholar was done using k.ywords“randomized controlled trials”,“antileishmanial”and“visceral leishmaniasis”.The outcomes included were cure rate,overall withdrawals,relapse rate,and treatment-emergent adverse events.Effect estimates through the frequentist network.meta-analysis approach were presented as OR with 95%CI.Rank.gram plots were used for identifying the“best intervention”based on p-scores obtained using the surface under the cumulative rank.ng.The risk.of bias was evaluated by using Pedro Scale.Results:Seventeen randomized controlled trials with 5143 visceral leishmaniasis patients who received different antileishmanial agents(amphotericin B,miltefosine,paromomycin,meglumine antimoniate,sodium stibogluconate,sitamaquine,and pentavalent antimonials)and met the inclusion criteria were included.For efficacy outcomes of the treatments,the rank.gram of the network.meta-analysis revealed that paromomycin(p-score=0.8148)has the highest probability of being best in the pool,followed by sodium stibogluconate(OR 0.82,95%CI 0.24-2.79,p-score=0.7580),amphotericin B+miltefosine(OR 0.66,95%CI 0.02-19.04,p-score=0.7329)as compared to the remaining treatments;however,the most of the treatment-emergent adverse events were reported with sitamaquine.Conclusions:Paromomycin reported the highest cure rates,while the maximum treatment-emergent adverse events were seen with sitamaquine.

关键词： Visceral leishmaniasis Treatment Efficacy Safety Network.meta-analysis

Regeneration of tree species in the sub-tropical forest of Alak.anda Valley, Garhwal Himalaya, India

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Forestry Studies in China 2013年第2期15卷 89-97页

作者： Radha BALLABHA J. k. tiwari P. tiwari Department of Botany and Microbiology HNB Garhwal UniversitySrinagar Garhwal 246174 Uttarakhand India

We studied the regeneration of tree species in the sub-tropical forest of Alak.anda Valley in Garhwal Himalaya, India. The overall regeneration status was fairly good in the study area. Seedling density ranged between 520 and 1,240 seedlings per ha while the density of saplings varied between 400 and 800 saplings per ha. Out of eight sites studied, five sites, viz., A1, A2, B1, B2 and C2 contained the highest number of seedlings （280-480 per ha） and saplings ,（200-440 per ha） for Pinus roxburghfi and remaining three sites viz., C1, D1 and D2 represented the highest number of seedlings （240-400 per ha） and saplings （200-240 per ha） for Anogeissus latifolius. The DBH class distribution of the tree species revealed that the highest number of individuals was concentrated in the lower diameter classes while smallest numbers were found in the higher diameter classes. Species such as Acacia catechu, Anogeissus latifolius, Dalbergia sissoo, Engelhardtia spicata, Lannea coromandelica, Mallotus philippensis and Pinus roxburghii have the larg- est number of saplings and seedlings in the lower DBH classes, suggesting that they have good regeneration potential. Other spec es such as Aegle marmelos, Bauhinia variegata, Bombax ceiba, Cassia fistula, Erythrina variegata, Haldinia ：cordifolia, Mangifera indica, Ougeinia oojeinensis, Phyllanthus emblica, Syzygium cumini, Terminalia alata and Toona hexandra have either no or very small number of saplings in the lower DBH classes which indicates that the status of these species implies poor regeneration.

关键词： Garhwal Himalaya disturbances regeneration tree species

Exploring the potential of artificial intelligence techniques in prediction of the removal efficiency of vortex tube silt ejector

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International Journal of Sediment Research 2023年第4期38卷 615-627页

作者： Sanjeev k.mar Chandra Shek.ar Prasad Ojha Nand k.mar tiwari Subodh Ranjan Department of Civil Engineering Indian Institute of Technology Department of Civil Engineering National Institute of Technology

A vortex tube silt ejector is a curative hydraulic structure used to remove sediment deposits from canals and is recognized as one of the most efficient substitutes for physically removing canal sediment. The spatially varied flow in the channel and the rotational flow behavior in the tube mak. the silt removal process complex. It is even harder to accurately predict the silt removal efficiency by traditional models accurately. However, artificial intelligence(AI) and machine learning approaches have emerged as robust substitutes for studying complex processes. Therefore, this research mak.s use of AI approaches; support vector machine(SVM), random forest(RF), random tree(RT), and multivariate adaptive regression spline(MARS) to compute the vortex tube silt ejection efficiency using the laboratory data sets. The outcomes of the artificial intelligence(AI)-based techniques also were compared with traditional models. It was found that the RT model(root mean square error, RMSE = 2.165, Nash Sutcliffe efficiency, NSE = 0.98) outperforms the other applied approaches which had relatively more significant result errors. The sensitivity analysis of the process depicts the extraction ratio as the k.y parameter in the computation of vortex tube silt ejector removal efficiency. The findings of the AI-based approaches discussed in the current study might be helpful for hydraulic engineers as well as researchers in the assessment of the removal efficiency of vortex tube silt ejectors.

关键词： Vortex tube silt ejector Support vector machine Random forest Random tree Multivariate adaptive regression spline

Liver or k.dney:Who has the oar in the gluconeogenesis boat and when?

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World Journal of Diabetes 2023年第7期14卷 1049-1056页

作者： Biswajit Sahoo Medha Srivastava Arpit k.tiyar Carolyn Ecelbarger Swasti tiwari Department of Molecular Medicine and Biotechnology Sanjay Gandhi Postgraduate Institute of Medical SciencesLucknow 226014India Department of Medicine Georgetown UniversityWashingtonDC 20057United States

Gluconeogenesis is an endogenous process of glucose production from noncarbohydrate carbon substrates.Both the liver and k.dneys express the k.y enzymes necessary for endogenous glucose production and its export into circulation.We would be remiss to add that more recently gluconeogenesis has been described in the small intestine,especially under high-protein,lowcarbohydrate diets.The contribution of the liver glucose release,the net glucose flux,towards systemic glucose is already well k.own.The liver is,in most instances,the primary bulk.contributor due to the sheer size of the organ(on average,over 1 k.).The contribution of the k.dney(at just over 100 g each)to endogenous glucose production is often under-appreciated,especially on a weight basis.Glucose is released from the liver through the process of glycogenolysis and gluconeogenesis.Renal glucose release is almost exclusively due to gluconeogenesis,which occurs in only a fraction of the cells in that organ(proximal tubule cells).Thus,the efficiency of glucose production from other carbon sources may be superior in the k.dney relative to the liver or at least on the level.In both these tissues,gluconeogenesis regulation is under tight hormonal control and depends on the availability of substrates.Liver and renal gluconeogenesis are differentially regulated under various pathological conditions.The impact of one source vs the other changes,based on post-prandial state,acid-base balance,hormonal status,and other less understood factors.Which organ has the oar(is more influential)in driving systemic glucose homeostasis is still inconclusive and lik.ly changes with the daily rhythms of life.We reviewed the literature on the differences in gluconeogenesis regulation between the k.dneys and the liver to gain an insight into who drives the systemic glucose levels under various physiological and pathological conditions.

关键词： Gluconeogenesis in the k.dney and liver Diabetes Hormonal regulation Metabolic acidosis Insulin resistance Net glucose metabolism