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腰骨藤的植物化学和药理学研究进展(英文)

中国天然药物 2012年第4期10卷 241-246页

作者： narendra kumar singh V. P. singh Department of Medicinal Chemistry Faculty of Ayurveda Institute of Medical Sciences Banaras Hindu University Varanasi-221005 India

Ichnocarpus frutescens R. Br. (Apocynaceae), is a woody climbing shrub, found almost in all parts of India. In India, tribes used this plant as a substitute of Indian Sarsaparilla (Hemidesmus indicus) for the treatment of atrophy, convulsions, cough, delirium, dysentery, measles, splenomegaly, tuberculosis, tumor, diabetes as a lactogogue, antipyretic, demulcent, diaphoretic and in skin diseases. Phytochemical investigations indicate that 28 compounds reported from the plant belong to various chemical category viz. phytosterol, triterpenes, flavonoids and various other phenolic compounds. Pharmacological activities of different parts of the plant reported include antiurolithiatic, hepatoprotective, antioxidant, analgesic, antipyretic, anti-inflammatory, antidiabetic, antihyperlipi-demic and antitumor activity. In the present review the literature data on the phytochemical and biological investigations on the I. frutescens are summarized up to March 2011.

关键词： Ichnocarpus frutescens Antitumor Anti-inflammatory Hepatoprotective

Dielectric Relaxation in Complex Perovskite Oxide Sr(Gd0.5Nb0.5)O3

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Materials Sciences and Applications 2012年第6期3卷 369-376页

作者： Pritam kumar Ajay kumar Sharma Bhrigunandan Prasad singh Tripurari Prasad Sinha narendra kumar singh Department of Physics Bose Institute Kolkata India University Department of Physics T. M. Bhagalpur University Bhagalpur India University Department of Physics V. K. S. University Ara India

The complex perovskite oxide a strontium gadolinium niobate (SGN) synthesized by solid-state reaction technique has single phase with tetragonal structure. X-ray diffraction (XRD) technique and scanning electron microscopy (SEM) were used to study the structural and microstructural properties of the ceramics, respectively. The XRD patterns of SGN at room temperature show a tetragonal structure. Studies of the dielectric constant and dielectric loss of compound as a function of frequency (50 Hz to 1 MHz) at room temperature, and as a function of temperature (60°C to 420°C) indicate polydispersive nature of the material. The logarithmic angular frequency dependence of the loss peak is found to obey the Arrhenius law with activation energy ~0.18 eV. The small value of activation energy of the compound (~0.18 eV) can be explained by mixed ionic-polaronic conductivity mechanism. The grain size of the pellet sample was found to be 1.92 μm. The frequency-dependant electrical data are analyzed in the framework of conductivity and electric modulus formalisms. The complex plane impedance plot shows the grain boundary contribution for higher value of dielectric constant in the law frequency region.

关键词： Dielectrics Perovskite Oxides X-Ray Diffraction Scanning Electron Micrograph

Structural and Electrical Characteristics of Ba(Fe0.5Nb0.5)O3-SrTiO3Ceramic System

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Materials Sciences and Applications 2011年第11期2卷 1593-1600页

作者： narendra kumar singh Pritam kumar Ajay kumar Sharma Ram Naresh Prasad Choudhary 不详

A complex structure of barium iron niobate, Ba(Fe0.5Nb0.5)O3 (BFN) and strontium titanate SrTiO3 (ST) was fabricated by a solid-state reaction method. The phase formation of Ba(Fe0.5Nb0.5)O3-SrTiO3 was checked using X-ray diffraction (XRD) technique. The X-ray structural analysis of BFN and BFN-ST ceramics, showed the formation of single-phase compound in the monoclinic system, which is a distorted structure of an ideal cubic perovskite. Careful examination of microstructures of the individual compounds of the system was done by the scanning electron micrograph (SEM), and confirms the polycrystalline nature of the systems. Detailed studies of dielectric and electrical impedance properties of the systems in a wide range of frequency (100Hz - 5MHz) and different temperatures (30°C-285°C) showed that these properties are strongly dependent on temperature and frequency.

关键词： Dielectrics Perovskite Oxides X-Ray Diffraction Scanning Electron Micrograph

Ameliorative Effects of Paclobutrazol via Physio-Biochemical and Molecular Manifestation in Rice under Water Deficit Stress

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Rice science 2024年第5期31卷 603-616,I0065页

作者： Chirag MAHESHWARI Nitin kumar GARG Archana singh Aruna TYAGI Indian Council of Agricultural Research-Indian Agricultural Research Institute New Delhi 110012India Sri Karan narendra Agricultural University JobnerRajasthan 303329India

To comprehensively explore the physio-biochemical and molecular changes of paclobutrazol(PBZ) at the ideal dose under water deficit stress(WDS) conditions, we investigated the effects of 100 mg/kg PBZ applied via drenching on various physio-biochemical and molecular parameters in three rice varieties(N22, IR64, and IR64 DTY1.1) under both mild [75%-80% relative water content(RWC)] and severe(60%-65% RWC) WDS conditions. The results showed that PBZ treatment positively influenced the physio-biochemical parameters, significantly increasing dry matter(16.27%-61.91%), RWC(6.48%-16.34%), membrane stability index(4.37%-10.35%), and total chlorophyll content(8.97%-29.09%) in the rice varieties under both mild and severe WDS. Moreover, PBZ treatment reduced drought susceptibility(0.83-0.95) and enhanced drought tolerance efficiency(60.92%-86.78%), indicating its potential as a stress-mitigating agent. Global methylation analysis revealed changes in DNA methylation patterns, indicating the regulatory influence of PBZ on gene expression. The expression analysis of genes involved in the diversification of geranylgeranyl pyrophosphate towards the biosynthesis of abscisic acid, gibberellin acid, and chlorophyll showed alterations in their expression levels, suggesting the involvement of PBZ in the isoprenoid pathway. Overall, this study provides valuable insights into the potential mechanisms by which PBZ modulates physiological and molecular responses in rice plants under WDS. The findings highlight the importance of PBZ as a promising agent for enhancing drought tolerance in rice and offer valuable information for future research in crop stress management.

关键词： rice paclobutrazol drought stress abscisic acid gibberellic acid

Study of Structural, Optical, Electrical and Dielectric Properties of Gd-Doped ZnO Composites Synthesized by Solid State Reaction Method

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Open Journal of Composite Materials 2024年第2期14卷 91-108页

作者： Santosh kumar Kundara Kanhaiya Chawla Dinesh kumar Yadav Chhagan Lal Balram Tripathi narendra Jakhar Department of Physics University of Rajasthan Jaipur India Sw. P.N.K.S. Government PG College Dausa India Government PG College Pratapgarh India S.S. Jain Subodh PG (Autonomous) College Jaipur India

In this manuscript, we are reporting structural, bonding, optical, dielectric, and electrical properties of Gd-doped ZnO composite samples (Zn1−xGdxO, x = 0, 0.05, 0.10) prepared by solid-state reaction method. XRD spectra confirm the wurtzite hexagonal phase with a grain size distribution of 42 - 47 nm. The FT-IR spectra confirm bonding behavior like Zn-O, O=C=O, and O-H stretching modes. FESEM micrographs show that the grains of crystallites possess nearly spherical morphology. Optical absorption spectra confirm that the optical band gap decreases systematically from 3.19 eV to 3.15 eV for x = 0.0 to x = 0.10 samples. For all samples, PL spectra exhibited near-band emission, blue emission, and green emission peaks. The dielectric constant decreases as the applied frequency increases. Hall effect results show that with increasing doping concentration of Gd, mobility and resistivity increase while bulk concentration decreases. Current-Voltage study shows that current increases when temperature is increased. Rare earth-doped ZnO is potential material used for optoelectronics and spintronics device applications. Properties of Gd-doped ZnO are studied by various research groups, but dielectric studies are limitedly reported. Therefore, the present research work aims to study the change of electrical, optical, and dielectric properties of Gd-doped ZnO for device applications.

关键词： ZnO:Gd Composites Optical Band Gap Green Emission Dielectric Constant

DNA computing over the ring Z4[v]/(v^2-v)

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International Journal of Biomathematics 2018年第7期11卷 149-166页

作者： narendra kumar Abhay kumar singh Department of Applied Mathematics Indian Institute of Technology (ISM) Dhanbad Jharkhand 826004India

In this paper,we discuss the DNA construction of general length over the finite ring =Z4+vZ4,with v2=v,which plays a very significant role in DNA *** discuss the GC weight of DNA codes over *** examples of reversible ... 详细信息

关键词： Cyclic codes DNA codes GC weight

Assessing the role of forest resources in improving rural livelihoods in West Bengal of India

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Regional Sustainability 2024年第2期5卷 75-88页

作者： Soumen BISUI Pravat kumar SHIT Research Center for Natural and Applied Science Raja Narendra Lal Khan Women’s College(Autonomous)Vidyasagar UniversityMidnapore721102India Postgraduate Department of Geography Raja Narendra Lal Khan Women’s College(Autonomous)Vidyasagar UniversityMidnapore721102India

Forest resources play a vital role in supporting the livelihoods of rural communities residing in forest-rich *** India,a forest-rich country,a significant proportion of non-timber forest products(NTFPs)is consumed locally,supporting numerous rural communities relying on forests for essential resources,such as firewood,timber,and *** study focuses on two forest-dominant districts in West Bengal of India,namely,Jhargram District and Paschim Medinipur ***,this study aims to enhance the understanding of forest-dependent communities by comparing the standard of living among different village ***,we categorized villages into three classes based on the distance from home to forests,including inner villages,fringe villages,and outer *** focus group discussions and household surveys,we explored the sources of local economy,income sources of household,and reasons for economic diversification in different village *** study findings confirm that substantial variations existed in the income sources and the standard of living in these *** income varied dramatically among the three village classes,with inner villages having greater forest income than fringe villages and outer ***,households in outer villages depended on forests and engaged in diverse economic activities for their *** with inner and fringe villages,households in outer villages derived a significant portion of their income from *** discrepancy can be attributed to challenges,such as inadequate transportation,communication,and underdeveloped market chains in inner ***,these findings emphasize the need to develop sustainable forest management practices,create alternative income-generation opportunities,and improve infrastructure and market access in inner villages,as well as promote economic diversification in outer *** targeted policy measures,these forest-rich regions can achi

关键词： Non-timber forest products(NTFPs) Forest resources Standard of living index Livelihood dependency index Income sources India

Spatio-temporal variation and propagation direction of coal fire in Jharia Coalfield,India by satellite-based multi-temporal night-time land surface temperature imaging

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International Journal of Mining Science and Technology 2021年第5期31卷 765-778页

作者： narendra singh R.S.Chatterjee Dheeraj kumar D.C.Panigrahi Department of Mining Engineering Indian Institute of Technology(Indian School of Mines)Dhanbad 826004India Geosciences Department Indian Institute of Remote SensingDehradun 248001India

In this paper,the spatio-temporal variation and propagation direction of coal fire were studied in the Jharia Coalfield(JCF),India during 2006–2015 through satellite-based night-time land surface temperature(LST)*** LST was retrieved from Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)night-time thermal-infrared data by a robust split-window algorithm based on scene-specific regression coefficients,band-specific hybrid emissivity,and night-time atmospheric *** LST-profile-based coal fire detection algorithm was formulated through statistical analysis of the LST values along multiple transects across diverse coal fire locations in the JCF in order to compute date-specific threshold temperatures for separating thermally-anomalous and background *** algorithm efficiently separates surface fire,subsurface fire,and thermally-anomalous transitional *** the observation period,it was noticed that the coal fire area increased significantly,which resulted from new coal fire at many places owing to extensive opencast-mining *** was observed that the fire propagation occurred primarily along the dip direction of the coal *** places,lateral-propagation of limited spatial extent was also observed along the strike direction possibly due to spatial continuity of the coal seams along ***,the opencast-mining activities carried out during 2009–2015 and the structurally weak planes facilitated the fire propagation.

关键词： Satellite-based night-time imaging Land surface temperature Coal fire Spatio-temporal variation Propagation direction Jharia Coalfield

Achievements and prospects of grass pea(Lathyrus sativus L.) improvement for sustainable food production

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The Crop Journal 2016年第5期4卷 407-416页

作者： Girish Prasad Dixit Ashok kumar Parihar Abhishek Bohra narendra Pratap singh ICAR-Indian Institute of Pulses Research (IIPR)

Grass pea offers an attractive choice for sustainable food production, owing to its intrinsic properties including limited water requirement and drought tolerance. However, low productivity and the presence of a neurotoxin(ODAP) have posed major obstacles to its genetic improvement. Also, biotechnological investments remain limited and the genome is complex and not well understood. Strategies that allow identification of genotypes with reduced ODAP content, coupling of low ODAP content with enhanced yield, and effective seed detoxification methods merit immediate attention. Breeder-friendly genomic tools are being increasingly made available to improve the efficiency of breeding protocols. To this end, the application of next-generation sequencing has provided a means of leveraging the repertoire of genomic resources for this somewhat neglected crop. In this review, we describe progress achieved in Lathyrus genetic improvement. We also explore potential opportunities in Lathyrus research and identify urgent research needs.

关键词： Grass pea Genetic resource Genetic improvement Molecular marker Molecular breeding Toxin