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Open Journal of Composite Materials 2013年第2期3卷 38-50页

作者： Dinesh Kumar shamsher bahadur singh Department of Civil Engineering Birla Institute of Technology and Science (BITS) Pilani India.

Cutouts are often provided in composite structural components for practical reasons. For instance, aircraft components such as wingspar, fuselage and ribs are provided with cutouts for access, inspection, fuel lines and electric lines or to reduce the overall weight. This paper addresses the effect of boundary condition on buckling and postbuckling responses, failure loads, and failure characteristics of composite laminate with various shaped cutouts (i.e., circular, square, diamond, elliptical-vertical and elliptical-horizontal) and having different lay-ups under in-plane shear (positive and negative) load, using finite-element method. The FEM formulation is based on the first order shear deformation theory in conjunction with geometric nonlinearity using von Karman’s assumptions. The 3-D Tsai-Hill criterion is used to predict the failure of a lamina while the onset of delamination is predicted by the interlaminar failure criterion. It is observed that the effect of boundary condition on buckling, first-ply failure and ultimate failure loads of a quasi-isotropic laminate with cutout is more for positive shear load than that for the negative shear load for almost all cutout shapes. It is also noted that under in-plane shear loads postbuckling stiffness of (0/90)4s laminate with circular cutout is maximum, while it is minimum for (45/—45)4s laminate with circular cutout, irrespective of boundary conditions.

关键词： Boundary Conditions Buckling Postbuckling Cutouts Composite Laminate FEM

Neuroprotective potential of Quercetin in combination with piperine against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity

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Neural Regeneration Research 2017年第7期12卷 1137-1144页

作者： shamsher singh Sumit Jamwal Puneet Kumar Department of Pharmacology I.S.F College of Pharmacy Ferozepur Road Moga Punjab India I.K. Gujral Punjab Technical University Jalandhar Punjab India

1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine（MPTP）is a neurotoxin that selectively damages dopaminergic neurons in the substantia nigra pars compacta and induces Parkinson＇s like symptoms in ***（QC）is a natural polyphenolic bioflavonoid with potent antioxidant and anti-inflammatory properties but lacks of clinical attraction due to low oral *** is a well established bioavailability enhancer used pre-clinically to improve the bioavailability of antioxidants（e.g.,Quercetin）.Therefore,the present study was designed to evaluate the neuroprotective potential of QC together with piperine against MPTP-induced neurotoxicity in ***（100μg/μL/rat,bilaterally）was injected intranigrally on days 1,4 and 7 using a digital stereotaxic ***（25 and 50 mg/kg,intragastrically）and QC（25 mg/kg,intragastrically）in combination with piperine（2.5 mg/kg,intragastrically）were administered daily for 14 days starting from day 8 after the 3^（rd） injection of *** day 22,animals were sacrificed and the striatum was isolated for oxidative stress parameter（thiobarbituric acid reactive substances,nitrite and glutathione）,neuroinflammatory cytokine（interleukin-1β,interleukin-6,and tumor necrosis factor-α）and neurotransmitter（dopamine,norepinephrine,serotonin,gamma-aminobutyric acid,glutamate,3,4-dihydroxyphenylacetic acid,homovanillic acid,and 5-hydroxyindoleacetic acid）*** infusion of MPTP into substantia nigra pars compacta led to significant motor deficits as evidenced by impairments in locomotor activity and rotarod performance in open field test and grip strength and narrow beam walk *** QC（25 and 50 mg/kg）and QC（25 mg/kg）in combination with piperine（2.5 mg/kg）,in particular the combination therapy,significantly improved MPTP-induced behavioral abnormalities in rats,reversed the abnormal alterations of neurotransmitters in the striatum,and alleviated oxidative stress and inflammatory response in the *** f

关键词： nerve regeneration 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine Quercetin Piperine Parkinson'sdisease excitotoxicity oxido-nitrosative stress neurotransmitters neural regeneration

Sericin alleviates pentylenetetrazole kindling epilepsy and associated comorbidities via modulation of GABA-T enzyme and mitochondrial activity

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Asian Pacific Journal of Tropical Biomedicine 2023年第10期13卷 431-442页

作者： Sania Grover Raj Kumar Narang shamsher singh I.K.Gujral Punjab Technical University JalandharPunjabIndia Department of Pharmaceutics ISF College of Pharmacy(An Autonomous College)Moga-142001PunjabIndia Neuroscience Division Department of PharmacologyISF College of Pharmacy(An Autonomous College)Moga-142001PunjabIndia

Objective:To assess the effect of sericin against pentylenetetrazole(PTZ)kindling epilepsy and its associated ***:Epilepsy was induced with PTZ at the dose of 30 mg/kg *** alternative days for 25 days in *** was administered orally at the doses of 250,500,and 1000 mg/kg for 35 *** behavioral activities were performed using an elevated plus maze,forced swim test,and Morris water maze test.A PTZ challenge test was conducted on day *** day 35,rats were sacrificed to perform oxidative stress,mitochondrial dysfunction,neuroinflammation,neurotransmitters,GABA-T activity,and histopathological ***:Sericin at 500 and 1000 mg/kg significantly reduced behavioral changes and neuroinflammatory cytokines,as well as improved oxidative stress,mitochondrial enzyme complex activity,neurotransmitter level,and GABA-T enzymatic activity(P<0.05).Moreover,sericin improved the neuronal survival altered by PTZ kindling in rat ***:Sericin mitigates epilepsy-associated secondary complications possibly by the modulation of mitochondrial enzyme complexes and GABA-T enzymatic activity.

关键词： Pentylenetetrazole Sericin GABA-T Epilepsy Anxiety Cognitive impairment

Suspended sediment dynamics in the meltwater of Chhota Shigri glacier, Chandra basin, Lahaul-Spiti valley, India

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Journal of Mountain Science 2018年第1期15卷 68-81页

作者： Virendra bahadur singh AL.RAMANATHAN School of Environmental Sciences Jawaharlal Nehru University

Present study shows suspended sediment dynamics in the meltwater of Chhota Shigri glacier,Himachal Pradesh,India for different melt seasons during the period *** suspended sediment concentration in the meltwater was found during the month of July 2011,2012 and 2014 constituting to 55.2%,48.3% and 46.9%,*** in 2013,maximum suspended sediment concentration was observed in August accounting for46.1% of the *** the other hand,maximum suspended sediment load was monitored in the month of July 2011,2012 and 2014 constituting 59.5%,63% and 55.7% of the total,*** in2013,maximum suspended sediment load was observed in the month of August accounting for 49.8% of the total suspended sediment *** distribution of suspended sediment concentration(SSC)and suspended sediment load(SSL)in the Chhota Shigri glacier shows higher value of SSC and SSL during the study period 2012 and 2013,which may be due to the presence of high glacial runoff and negative mass balance of the studied area during these time *** diurnal variation has been observed in the SSC of *** correlation was observed between SSC and SSL with *** the other hand,SSC and SSL also showed strong exponential correlation with air temperature of the studied *** yield from the catchment of Chhota Shigri glacier is high during the peak melt season(July and August)and low during the late melt season(September and October).The average value of erosion rate for Chhota Shigri glacier basin during the study period 2011-2014 was calculated to be 1.1mm/yr,which is lower than the average erosion rate of other Himalayan glaciers such as Rakiot,Chorabari and Gangotri glaciers,which may be caused by its geological setting containing high erosion resistant rocks such as granite,granite gneiss and porphyritic granite.

关键词： Suspended sediment concentration Hysteresis Sediment yield Erosion rate Western Himalaya Chhota Shigri glacier

Cryptotanshinone ameliorates cladribine-induced cognitive impairment in rats

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Asian Pacific Journal of Tropical Biomedicine 2023年第7期13卷 296-305页

作者： Khadga Raj Aran G.D.Gupta shamsher singh Neuroscience Division Department of PharmacologyISF College of Pharmacy(An Autonomous College)MogaPunjabIndia-142001 I.K.Gujral Punjab Technical University JalandharIndia Department of Pharmaceutics ISF College of PharmacyMogaPunjabIndia-142001

Objective:To evaluate the neuroprotective effect of cryptotanshinone against cladribine-induced cognitive impairment in ***:Rats were administered with cladribine(1 mg/kg,p.o.)and cryptotanshinone(10 and 20 mg/kg,i.p.)for four *** tests such as Morris water maze and elevated plus maze were conducted to check memory impairment caused by *** day 29,all rats were sacrificed,and the brains were separated for estimation of neuroinflammatory factors,biochemical parameters,neurotransmitters,Aβ(1-42),blood-brain barrier permeability,nuclear factor erythroid 2-related factor 2(Nrf2),and brain-derived neurotrophic factor(BDNF).Results:Treatment with cryptotanshinone dose-dependently enhanced spatial memory,improved the levels of neurotransmitter and antioxidant enzymes,and suppressed proinflammatory cytokine *** also decreased Aβ(1-42)accumulation and increased the levels of Nrf2 and BDNF in the ***,the histopathological results showed that cryptotanshinone reduced cladribine-induced neuronal death in the ***:Cryptotanshinone exhibits a promising neuroprotective effect against cladribine-induced cognitive impairment in preclinical studies,and may be a potential phytochemical for the treatment and management of cognitive impairment.

关键词： Alzheimer's disease Cladribine Cryptotanshinone Neurotransmitters Neuroprotective Proinflammatory cytokines Cognitive deficit

Rock excavation using surface miners: An overview of some design and operational aspects

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International Journal of Mining Science and Technology 2013年第1期23卷 33-40页

作者： Prakash Amar Murthy Vemavarapu Mallika Sita Ramachandra singh Kalendra bahadur Central Institute of Mining & Fuel Research Dhanbad 826015 India Indian School of Mines Dhanbad 826004 India

Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of surface miners are manufactured today based on cutting drum placement and design specifications. Selective mining without drilling and blasting, high production and small size products are some of the prominent attractive features obtained with these moving marvels. This machine can be used with good efficiency in soft to medium hard rock (100-120 MPa). This paper synthesizes the different applications, equipment models, features offered, operating methods, cutting performance assessment models as well as typical production performance of surface miner in coal and limestone mines of India. Engine hour metre reading, diesel and pick consumptions are linearly influenced by production. The emphasis for future research is also brought out.

关键词： Surface miner Cutting performance Compressive strength Operating methods

Seasonal variations and health risk assessment of trace elements in the Badigad River,lesser Himalayas,Nepal

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Acta Geochimica 2023年第4期42卷 689-703页

作者： Ramesh Raj Pant Kiran Bishwakarma Kshitiz Kandel Sudip Poudel Jharana Nepal Bhanu Bhakta Neupane Virendra bahadur singh Central Department of Environmental Science Institute of Science and TechnologyTribhuvan UniversityKathmanduNepal University of Chinese Academy of Sciences Beijing 100049China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China Central Department of Chemistry Institute of Science and TechnologyTribhuvan UniversityKathmanduNepal Department of Environmental Studies Ram Lal Anand CollegeUniversity of DelhiNew Delhi 110021India

The consumption of contaminated river water can have severe effects on human *** study aims to investigate the trace elements(TEs)content and their health risk assessment in the Badigad River Basin in the lesser Himalayas of *** total,44 water samples were collected from 22 different sites during the pre-monsoon and monsoon seasons,and 25 TEs were *** matrix and principal component analysis(PCA)were used to analyze the potential relationship between the measured TEs and their source ***,the water quality index(WQI),metal index(MI),and cancer index(CI)were *** TEs content in all samples were found to be within the WHO recommended guideline for drinking and domestic *** dominancy order of the TEs was observed as Sr>Ba>Li>Rb>Zn>Cr>Sc>Mn>Ti>Cu>As>Ni>Co>U>V>Pb>Cs>Ga>Y>Tl>Th>Zr>Bi>Cd>*** PCA analysis suggested that TEs could have natural,anthropogenic,and mixed *** WQI indicated that the river water is safe from a human health *** MI suggested that Badigad River can be considered safer for drinking purposes,and the cancer index(CI)showed that all the reported TEs are at low-risk *** findings of this study could be useful for government agencies in developing more sustainable water management policies in the ***,it is suggested that further investigations should be conducted in terms of other hydrogeochemical variables,including major ions,at spatiotemporal levels for the sustainability of the river basin.

关键词： Trace elements Water quality Health risk assessment Multivariate analysis Badigad River

Evolution of Weak Shock Waves in Perfectly Conducting Gases

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Applied Mathematics 2011年第5期2卷 653-660页

作者： Lal Pratap singh Dheerendra bahadur singh Subedar Ram 不详

This article aims at studying one dimensional unsteady planar and cylindrically symmetric flow involving shocks under the influence of magnetic field. The method of generalized wavefront expansion (GWE) is employed to derive a coupled system of nonlinear transport equations for the jump of field variables and of its spatial derivatives across the shock, which, in turn determine the evolution of wave amplitude and admit a solution that agrees with the classical decay laws of weak shocks. A closed form solution exhibiting the features of nonlinear steepening of the wave front. A general criterion for a compression wave to steepen into a shock is derived. An analytic expression elucidating how the shock formation distance is influenced by the magnetic field strength is obtained. Also, the effects of geometrical spreading and nonlinear convection on the distortion of the waveform are investigated in the presence of magnetic field.

关键词： Magnetogasdynamic Flow Weak Shock Induced Discontinuity Generalized Wavefrontexpansion (GWE)

One-Step One Chemical Synthesis Process of Graphene from Rice Husk for Energy Storage Applications

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Graphene 2017年第3期6卷 61-71页

作者： Pushpendra singh Jitendra bahadur Kaushik Pal Centre of Nanotechnology Indian Institute of Technology Roorkee India Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee India

Few layer graphene was synthesized using rice husk ash (RHA) and potassium hydroxide (KOH). This methodology demonstrates the utility of RHA as carbon source for graphene synthesis and as a protective barrier against oxidation of parent rice husk and KOH mixture. Oxidation may occur during synthesis process due to high temperature annealing of RHA and KOH mixture. Electrochemical characterization showed decent capacitance value 86 F·g-1 at 500 mV·s-1. XRD and Raman spectroscopy analysis confirmed the presence of graphitic structure. Transmission electron microscopy visually confirmed presence of few layer graphene. Novelty of this synthesis technique can be described as one-pot, one chemical synthesis technique. Use of natural precursor makes this technique highly cost effective for large scale production.

关键词： Rice Husk Graphene Silicon Dioxide Cyclic Voltammetry

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磁共振引导聚焦超声术治疗子宫肌瘤临床研究

磁共振引导聚焦超声术治疗子宫肌瘤临床研究

作者： ASHISH bahadur singh 吉林大学

学位级别：硕士

目的通过无灌注区体积来评估MR引导超声聚焦治疗子宫肌瘤的效果。材料本研究为单中心的子宫肌瘤治疗评估,已通过医院伦理审查委员会批准。病人通过MR引导超声聚焦治疗系统(3.0T GE healthcare Ex Ablate 2000 s系统)来进行子宫肌瘤治疗... 详细信息

目的通过无灌注区体积来评估MR引导超声聚焦治疗子宫肌瘤的效果。材料本研究为单中心的子宫肌瘤治疗评估,已通过医院伦理审查委员会批准。病人通过MR引导超声聚焦治疗系统(3.0T GE healthcare Ex Ablate 2000 s系统)来进行子宫肌瘤治疗,该系统2004年通过美国食品及药物管理局批准。所有患者均行盆腔MR扫描,包括术前及术后T1成像及T2成像,所有图像由两名医生独立评估。子宫肌瘤分级为低信号和高信号,如子宫肌层和腹直肌信号。子宫肌瘤是30岁以上的女性中最常见的良性女性生殖系统肿瘤,患病率在100%,近年来发病率呈逐年上升趋势。临床症状包括:月经量增多、经期延长,贫血,压迫症状,压迫膀胱:尿频、尿急;排尿不畅甚至尿潴留,压迫直肠:大便不畅、排便后不适感,压迫输尿管(阔韧带肌瘤):肾盂积水;下腹坠胀感、腰背酸痛;白带增多;不孕或流产:自然流产率高于正常人群。适应症包括:有症状的子宫肌瘤患者、有生育需求的子宫肌瘤患者。禁忌症包括:带蒂的浆膜下肌瘤、活动期盆腔炎或全身感染性疾病、有广泛的下腹部瘢痕、严重心肺肾功能不全、患者下腹存在金属置入物或宫内节育器、患者对核磁共振成像对比试剂过敏、严重的幽闭恐惧症。图像引导聚焦超声手术(FUS)是一个迅速发展的技术,利用聚焦超声(HIFU)与MR图像引导(MRg FUS)来达到治疗目的。该技术具有广泛的应用,可以实现良性和恶性肿瘤,疼痛等疾病的无创治疗。在治疗过程中,能够通过核磁共振进行指导,精确地观测肿瘤消融情况。MRg FUS可以实时地测量病灶在治疗过程中的温度,能够提供温度图。本技术最大的优点是MRg FUS完全无创、无辐射。MR引导HIFU的治疗方式提供了精确和动态评估的温度,通过动态温度分布来确定的热剂量传递到组织。在核磁实时的动态扫描情况下,同时进行实时的温度监测,通过超声波进行能量聚焦,穿过人体组织将能量聚焦到病灶,进一步将声能转化为热能,病灶温度快速升高,从而通过热消融的方法使病灶发生坏死。此外,由于病灶以外的组织并没有超声的聚焦,因此超声波所经过的路径的组织未发生热消融。2004,美国食品和药物管理局(FDA)批准的MRI引导聚焦超声(MRg FUS)是一种治疗子宫肌瘤的无创热消融方法。这种新技术使温度上升后足以引起凝固性坏死。结果P值小于0.05被认为有统计学显著差异。MR引导超声聚焦治疗子宫肌瘤的术前和术后的无灌注区体积具有显著性差异,p值<0.05(z=-2.803,p=0.005)。统计结果分析表明,治疗前均值为198.81±292.11 cm,治疗后均值为58.49±87.98cm,无灌注区体积比约为70.58%。症状严重程度评分(出血和压力)的统计结果也有统计学意义。出血症状(Z=-2.803,P=0.005)和压力症状(Z=-2.070,P=0.038)。结论MR引导超声聚焦治疗子宫肌瘤具有较好的前景。术后的无灌注区体积能够评估治疗效果。与常规的治疗方法相比较,超声的空化效应和热效应能够使病灶的焦点组织温度升高到60-100摄氏度的有效治疗范围,能够使病灶中的蛋白质发生凝固性坏死,从而达到治疗的目的。MRg FUS具有很多优点,如治疗时间较短、治疗后仅需短暂的观察,如果无异常并发症则可以当天离开医院,无需住院,比较适合当前快速的工作节奏;该技术是无创的治疗方法,治疗过程中,聚焦点界线清晰,有效的避免了超声经过的正常组织的损伤,治疗后不会发生重大的不良反应事件;此外该治疗方法具有可控性及可预测性,治疗过程中可以实时的监测温度,在此基础上调整参数来达到最佳的治疗效果。筛查注意事项包括:瘢痕较正常组织吸收更多超声能量。具有腹部瘢痕的患者满足以下条件时可进行治疗:瘢痕贴可完全覆盖瘢痕,通过调整靶点角度可避开瘢痕组织。在某些情况下,当瘢痕位于目标区域前方时,通常无法避开,当无法将重要结构(如瘢痕,皮肤皱褶或不规则结构)从声束路径上移开时,不要进行Ex Ablate治疗。肠道内可能存在吸收能量的粒子和空气(造成能量反射),超声传播路径上不能有肠道阻挡。目标肌瘤中心距离骨表面应大于4cm,超声远场能量可能引起骨骼温度升高,从而导致神经受热。治疗非常大的肌瘤需要相当长的治疗时间,并且可能部分肌瘤无法治疗到出于安全考虑,需与浆膜保持1cm安全距离,因此,非常小的浆膜下肌瘤(<2cm)无法安全的治疗。对于多发肌瘤,极有可能其中部分肌瘤无法治疗。增强图像上未强化的肌瘤本身不具活性、治疗这样的肌瘤无法提供额外的益处。治疗带蒂浆膜下肌瘤(与子宫连接处<肌瘤周长的50%)的安全性和有效性尚未明确。治疗上述肌瘤可能出现治疗后肌瘤从子宫脱落,并需借助外科手术将脱落的肌瘤从盆腔取出。该技术是通过超声聚焦,无X射线等其它辐射所造成的损坏,是安全和有效的无创技术,有望在临床推广应用。

关键词： MR引导超声聚焦治疗无灌注区体积子宫肌瘤