检索结果-南通市图书馆

Characterization of optical transitions of Eu^(3+) in lanthanum oxychloride nanophosphor

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2011年第4期29卷 345-348页

作者： A. Choubey S. Som m. Biswas S.K. sharma Department of Applied Physics Indian School of Mines Dhanbad 826004 India

This paper presented the studies on the optical properties and calculation of spectral parameters of europium doped lanthanum oxychloride nanophosphor for their possible applications in optoelectronic devices. The compound was doped with 0.1 mol% Eu3＋ ions. The X-ray diffraction study of prepared sample suggested the tetragonal structure with particle size in the range of 18–21 nm. The photoluminescence （PL） emission spectra showed the bright emission in orange-red region from 580 to 630 nm. The most intense emission peak at 621 nm was due to transition 5D0→7F2 in energy levels of Eu3＋ ions. The spectral parameters were calculated from the absorption and emission spectra using Judd-Ofelt intensity parameters. The calculated values of the oscillator strength corresponding to the three transitions 7F1→5D1, 7F1→5D2 and 7F0→5D2 observed at 535, 472 and 465 nm in absorption spectra were 0.30×10–6, 1.36×10–6 and 0.63×10–6, respectively. The value of transi- tion probability （A）, stimulated emission cross-section （） and radiative lifetime （τrad） corresponding to 621 nm emission peak （transition 5D0→7F2） were 308 s–1, 1.22×10–21 cm2 and 3.24×10–3 s, respectively.

关键词： X-ray diffraction optical absorption photoluminescence spectral parameters rare earths

Transfusion-transmitted virus in association with hepatitis A-E viral infections in various forms of liver diseases in India

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第15期12卷 2432-2436页

作者： m Irshad Y sharma I Dhar J Singh YK Joshi Clinical Biochemistry Division Department of Laboratory medicine All India Institute of Medical SciencesAnsari NagarNew Delhi 110029India Department of Gastroenterology & Human Nutrition Unit All India Institute of medical Sciences Ansari NagarNew Delhi-110029India

AIm： To describe the prevalence of transfusiontransmitted virus （TTV） infection in association with hepatitis A-E viral infections in different forms of liver diseases in North India. mETHODS： Sera from a total number of 137 patients, including 37 patients with acute viral hepatitis （AVH）, 37 patients with chronic viral hepatitis （CVH）, 31 patients with cirrhosis of liver and 32 patients with fulminant hepatic failure （FHF）, were analyzed both for TTV-DNA and hepatitis A-E viral markers. Presence of hepatitis B virus （HBV）, hepatitis C virus （HCV） and hepatitis E virus （HEV） infections was detected in different proportions in different groups. moreover, rrV-DNA was simultaneously tested in 100 healthy blood donors also. RESULTS： None of the patients had hepatitis A virus （HAV） and hepatitis D virus （HDV） infections. Overall prevalence of TTV-DNA was detected in 27.1% cases with AVH, 18.9% cases with CVH, 48.4% cases with cirrhosis and 9.4% cases with FHF. TTV-DNA simultaneously tested in 100 healthy blood donors showed 27% positivity. On establishing a relation between TTV infection with other hepatitis viral infections, TTV demonstrated co-infection with HBV, HCV and HEV in these disease groups. Correlation of TTV with ALT level in sera did not demonstrate high ALT level in TTV-infected patients, suggesting that TI-V does not cause severe liver damage. CONCLUSION： TTV infection is prevalent both in patients and healthy individuals in India. However, it does not have any significant correlation with other hepatitis viral infections, nor does it produce an evidence of severe liver damage in patients with liver diseases.

关键词： Transfusion-transmitted virus HCV hepatitis AVH

Thermal-Based Free Vibration and Buckling Behavior of Bio-inspired Cross-and Double-Helicoidal/Bouligand Laminated Composite Plates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta mechanica Solida Sinica 2023年第6期36卷 933-942页

作者： Sagar Paruthi Neha sharma Reeta Gulia Lokesh Choudhary Anshu sharma m.O.Belarbi Aman Garg Li Li H.D.Chalak Department of Civil Engineering DPG Institute of Technology and ManagementGurugramHaryana 122004India Department of multidisciplinary Engineering The NorthCap UniversityGurugramHaryana 122017India Department of Chemical Engineering Kangwon National UniversityChuncheon Campus1 GangwondaehakgilChuncheon-SIGangwon-Do 24341Republic of Korea Laboratoire de Recherche en Génie Civil(LRGC) Universitéde BiskraB.P.145R.P.07000 BiskraAlgeria State Key Laboratory of Digital manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Department of Civil Engineering National Institute of Technology KurukshetraHaryana 133019India

Inspired by living organisms,helicoidal structures are becoming increasingly important in replacing the conventional lamination scheme to enhance the toughness,strength,and stiffness of *** helicoidal laminated composites,each layer is rotated by a specific angle with respect to the previous *** the present study,an attempt has been carried out to compare the free vibration and buckling behavior of the double-helicoidal and cross-helicoidal bio-inspired laminated composite plates under thermal *** influence of lamination scheme,aspect ratio,end conditions,thermal conditions,sideto-thickness ratio,and skew angle on the free vibration and buckling behavior of the plate is *** performance of helicoidal laminated composite plates is compared with that of cross-ply and quasi-isotropic *** study reveals that the helicoidal composites outperform the cross-ply and quasi-isotropic *** most cases studied,the cross-helicoidal plate exhibits stiff behavior.

关键词： Double-helicoidal plate Single-helicoidal plate Free vibration Buckling Bio-inspired plate

Effect of intermittent treatment with tamoxifen on reproduction in male rats

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2001年第2期3卷 115-119页

作者： m.K.Gill-sharma N.Balasinor P.Parte Department of Neuroendocrinology Institute for Research in Reproduction(ICMR) Parel Mumbai 400012 IndiaDepartment of Neuroendocrinology Institute for Research in Reproduction(ICMR) Parel Mumbai 400012 IndiaDepartment of Neuroendocrinology Institute for Research in Reproduction(ICMR) Parel Mumbai 400012 India

Aim: To identify the antifertility effect of intermittent oral administration of tamoxifen in male rat. methods:Tamoxifen was administered orally at a dose of 0.4 mg·kg^(-1)·d^(-1) with an intermittent regime for 120 days. Treatedand control rats were mated with cycling female rats on days 60, 90 and 120 of treatment. The mated males were sacri-ficed and the weights of reproductive organs were recorded, and the serum levels of LH, FSH, testosterone and estradi-ol estimated by radioimmunoassay. In the female rats, the numbers of implantation sites, corpora lutea, and numbersof normal and resorbed foetuses were recorded on d 21 of gestation. The potency, fecundity, fertility index, litter sizeand post-implantation loss were then calculated. Results; The fecundity of male rats was completely suppressed bytamoxifen while the potency was maintained at the control level. The fertility index was significantly decreased. No vi-able litters were sired. Post implantation loss, indicative of non-viable embryos, was observed but was not significantlyincreased above the control level. The weights of the testes, epididymides, ventral prostate and seminal vesicles weresignificantly reduced. The blood LH and testosterone levels were significantly decreased, but not FSH and ***; Intermittent oral tamoxifen administration completely suppressed the fecundity of adult male rats withreserved potency.

关键词： tamoxifen estrogen intermittent treatment fertility

3D biofabrication of vascular networks for tissue regeneration:A report on recent advances

在线全文

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2018年第5期8卷 277-296页

作者： m.D.Sarker Saman Naghieh N.K.sharma Xiongbiao Chen Division of Biomedical Engineering College of Engineering University of Saskatchewan Department of mechanical Engineering College of Engineering University of Saskatchewan

Rapid progress in tissue engineering research in past decades has opened up vast possibilities to tackle the challenges of generating tissues or organs that mimic native structures. The success of tissue engineered constructs largely depends on the incorporation of a stable vascular network that eventually anastomoses with the host vasculature to support the various biological functions of embedded cells. In recent years, significant progress has been achieved with respect to extrusion, laser, micro-molding, and electrospinning-based techniques that allow the fabrication of any geometry in a layer-by-layer fashion. moreover, decellularized matrix, self-assembled structures, and cell sheets have been explored to replace the biopolymers needed for scaffold fabrication. While the techniques have evolved to create specific tissues or organs with outstanding geometric precision, formation of interconnected, functional, and perfused vascular networks remains a challenge. This article briefly reviews recent progress in 3D fabrication approaches used to fabricate vascular networks with incorporated cells, angiogenic factors, proteins, and/or peptides. The influence of the fabricated network on blood vessel formation, and the various features, merits, and shortcomings of the various fabrication techniques are discussed and summarized.

关键词： 3D bioprinting Tissue engineering Vascularization Extrusion Laser-based printing Co-axial printing

A Novel Hybrid Clustering Based Transmission Protocol for Wireless Body Area Networks

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2021年第11期69卷 2459-2473页

作者： Neelam.sharma Harshita Chadha Karan Singh B.m.Singh Nitish Pathak Research Scholar Computer Science and EngineeringUttarakhand Technical University(UTU)DehradunIndia Computer Science and Engineering Maharaja Agrasen Institute of TechnologyNew DelhiIndia School of Computer&Systems Sciences Jawaharlal Nehru University(JNU)DelhiIndia College of Engineering Roorkee UTUDehradunIndia Department of Information Technology KIET Group of InstitutionsGhaziabadIndia

Wireless sensor networks are a collection of intelligent sensor devices that are connected to one another and have the capability to exchange information packets amongst *** recent years,this field of research has become increasingly popular due to the host of useful applications it can potentially serve.A deep analysis of the concepts associated with this domain reveals that the two main problems that are to be tackled here are throughput enhancement and network security *** present article takes on one of these two issues namely the throughput *** the purpose of improving network productivity,a hybrid clustering based packet propagation protocol has been *** protocol makes use of not only clustering mechanisms of machine learning but also utilizes the traditional forwarding function approach to arrive at an optimum *** result of the simulation is a novel transmission protocol which significantly enhances network productivity and increases throughput value.

关键词： Forwarding function wireless sensor networks WSNs WBANs energy characteristics clustering hybrid mechanism dissipated energy network stability

High-pressure investigations on Piplia Kalan eucrite meteorite using in-situ X-ray diffraction and ^(57)Fe mssbauer spectroscopic technique up to 16 GPa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2016年第2期7卷 265-271页

作者： Usha Chandra K.K. Pandey G. Parthasarathy Surinder m. sharma Department of Physics University of Rajasthan Jaipur 302 004 India High Pressure & Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai 400 085 India CSIR-National Geophysical Research Institute Uppal Road Hyderabad 500 007 India

We report here high-pressure investigations on Piplia Kalan eucrite-a member of HED （Howardite -Eucrite-Diogenite） family from asteroid 4-Vesta based on synchrotron X-ray diffraction （up to 16 GPa） and ^57Fe mossbauer spectroscopy （up to 8 GPa）. Dominant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining amorphous character at 16 GPa. These phase transitions of individual components could be explained simultaneously through variations in high-pressure XRD patterns and the mossbauer parameters. most prominent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in mossbauer parameters and population inversion of Fe^2＋ in m1 and m2 sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of - 12 GPa implied residual stress experienced due to shock impact. The presence of high pressure （monoclinic） phase of pigeonite and ferrosilite at ambient condition in this eucrite sample confirmed earlier suggestions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences amongst HED members.

关键词： meteorites High pressure X-ray diffraction mossbauer spectroscopy Eucrites synchrotron radiation Ferrosilite

Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2011年第7期17卷 867-897页

作者： Chakshu sharma Karim m Eltawil Paul D Renfrew mark J Walsh michele molinari Department of Surgery Queen Eliz-abeth Ⅱ Health Sciences Center Dalhousie University

Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic.

关键词： Diagnosis Epidemiology Palliation Pancreatic cancer Therapy

Ecological Consequences of Land Use Change: Forest Structure and Regeneration across the Forest-grassland Ecotone in mountain Pastures in Nepal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of mountain Science 2014年第4期11卷 838-849页

作者： Lila Nath sharma Ole Reidar VETAAS Ram Prasad CHAUDHARY Inger Elisabeth mREN Department of Geography University of Bergen Bergen 5020 Norway Research Centre for Applied Science and Technology and Central Department of Botany Tribhuvan UniversityKathmandu 977 Nepal

The ecotone, the spatial transition zone between two vegetation communities, is claimed to have more species than the adjoining communities. However, empirical studies do not always confirm higher richness at the ecotone. The ecotone position and structure are dynamic over time and space and it is driven by the changes in climate, land use or their interaction. In this context, we assessed the forest- grassland ecotone of temperate mountains in central Nepal by i） comparing species composition and richness across the ecotone, ii） analyzing if the forestgrassland ecotone is shifting towards the grassland center by colonizing them with trees, and iii） discussing the consequence of changed disturbance regime in the dynamics of this ecotone and the surrounding grasslands. We analyzed vegetation data sampled from belt transects laid across the forest- grassland ecotone in semi-natural grassland patches. Vegetation data consisting of species richness and composition, and size structure and regeneration of the two most dominant tree species, namely Rhododendron arboreum and Abies spectabilis, from the transects, were used to analyze the trend of the forest-grassland ecotone. Forest and grasslands were different in terms of floristic composition and diversity. Vascular plant speciesrichness linearly increased while moving from forest interior to grassland center. Spatial pattern of tree size structure and regeneration infers that forest boundary is advancing towards the grasslands at the expense of the grassland area, and tree establishment in the grasslands is part of a suceessional process. Temporally, tree establishment in grasslands started following the gradual decline in disturbance. We argue that local processes in terms of changed land use may best explain the phenomenon of ecotone shift and consequent forest expansion in these grasslands. We underpin the need for further research on the mechanism, rate and spatial extent of ecotone shift by using advaneed tools to

关键词： Ecotone shift Grasslands Forest Landuse change Rhododendron