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Deciphering the role of microRNA 21 in cancer stem cells(CSCs)

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Genes & Diseases 2016年第4期3卷 277-281页

作者： Durairaj Sekar Ramalingam Krishnan Mani Panagal Pethanen sivakumar Vincent Gopinath Venugopal Basam Narayana Medical College and Hospital ChinthareddypalemNellore 524002India Stem Cell Division Cryovault Biotech India Pvt LtdBangalore 560018India Department of Biotechnology Annai College of Arts and ScienceKumbakonamTamil NaduIndia Department of Zoology Arumugam Pillai Seethai Ammal CollegeTiruppatturTamil NaduIndia

Irrespective of positive developments of cancer treatment,the mortality due to various cancers remains high and the mechanisms of cancer initiation and the development also remains *** we know that microRNAs are considered to be a short noncoding RNA molecules consisting of 21e25 nucleotides(nt)in length and they silence their target genes by inhibiting mRNA translation or degrading the mRNA molecules by binding to their 30-untranslated(UTR)region and play a very important role in cancer *** evidences indicate that miR-21 is over expressed in cancer stem cells and plays a vital role in cell proliferation,apoptosis,and *** though an increased expression level of miR-21 has been observed in cancer stem cells,studies related to the role of miR-21 in cancer stem cells are *** main aim of this mini review is to explain the potency of miR-21 in various cancer stem cells(CSCs)and as a new target for therapeutic interventions of cancer progression.

关键词： CSCs Cancer stem cells miR-21 miRNAs RNAs UTR

Development of Non-Shrinking Soft Ferrite Composition Useful for Microinductors Applications

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World Journal of Condensed Matter Physics 2011年第3期1卷 105-119页

作者： N Varalaxmi K sivakumar 不详

NiCuZn Ferrites are widely employed for many electronic applications, but can be replaced by MgCuZn ferrites owing to their superior properties like high initial permeability, high resistivity, low magnetostriction, environmental stability and low cost. Three series of NiMgCuZn ferrites were prepared by conventional sintering process. The formation of single phase in these ferrites was confirmed by x-ray diffraction. Initial permeability measurements on these samples were carried out in the temperature range of 30-400℃. The effect of the external applied stress on the open magnetic circuit type coil with these ferrites was studied by applying uniaxial compressive stress parallel to magnetizing direction and the change in the inductance was measured. The variation of ratio of inductance (ΔL/L)% increases upto certain applied compressive stress and there after it decreases, showing different stress sensitivities for different compositions of ferrites studied in the present work. With a view to develop stress insensitive NiMgCuZn ferrite, a low stress sensitivity composition among all the ferrites studied was chosen and different amounts of SiO2 were added to it and a series of ferrite compositions were prepared. The variation of ratio of inductance (ΔL/L)% with external applied compressive stress was examined. These results show that, in a particular composition of 0.05 wt% SiO2added Ni0.3Mg0.3Cu0.1Zn0.3Fe2O4 ferrite exhibited stress insensitivity. It was noticed that addition of SiO2 was found to be effective in reducing the stress sensitivity. This was confirmed from the elastic behaviour studies at room temperature on these ferrite samples. These studies were carried out to develop a ferrite composition for its use as core material for microinductor applications.

关键词： X-ray diffraction Ferrite composites Initial permeability Microinductors Stress Insensitivity SEM photographs

Production and mechanical properties of nano SiC particle reinforced Ti-6Al-4V matrix composite

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Transactions of Nonferrous Metals Society of China 2017年第1期27卷 82-90页

作者： G.sivakumar V.ANANTHI S.RAMANATHAN CISL Department of PhysicsAnnamalai UniversityTamilnadu 608002India Physics Section FEATAnnamalai UniversityTamilnadu 608002India Manufacturing Engineering Department Annamalai UniversityTamilnadu 608002India

Different mass fractions （0, 5%, 10%, and 15%） of the synthesized nano SiC particles reinforced Ti-6Al-4V （Ti64） alloy metal matrix composites （MMCs） were successfully fabricated by the powder metallurgy method. The effects of addition of SiC particle on the mechanical properties of the composites such as hardness and compressive strength were investigated. The optimum density （93.33%） was obtained at the compaction pressure of 6.035 MPa. Scanning electron microscopic （SEM） observations of the microstructures revealed that the wettability and the bonding force were improved in Ti64 alloy/5% nano SiCp composites. The effect of nano SiCp content in Ti64 alloy/SiCp matrix composite on phase formation was investigated by X-ray diffraction. The correlation between mechanical parameter and phase formation was analyzed. The new phase of brittle interfaced reaction formed in the 10% and 15% SiCp composite specimens and resulted in no beneficial effect on the strength and hardness. The compressive strength and hardness of Ti64 alloy/5% nano SiCp MMCs showed higher values. Hence, 5% SiCp can be considered to be the optimal replacement content for the composite.

关键词： titanium alloy nano SiC particle powder metallurgy hardness compressive strength

Parametric Tolerance Analysis of Mechanical Assembly Using FEA and Cost Competent Tolerance Synthesis Using Neural Network

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Journal of Software Engineering and Applications 2010年第12期3卷 1148-1154页

作者： Govindarajalu Jayaprakash Karuppan sivakumar 不详

Tolerance design plays an important role in the modern design process by introducing quality improvements and limiting manufacturing costs. Tolerance synthesis is a procedure that distributes assembly tolerances between components or distributes final part design tolerances between related tolerances. Traditional tolerance design assumes that all objects have rigid geometry, overlooking the role of inertia effects on flexible components of assembly. The variance is increasingly stacked up as components are assembled without considering deformation due to inertia effects. This study deals with the optimal tolerance design for an assembly simultaneously considering manufacturing cost, quality loss and deformation due to inertia effect. An application problem (motor assembly) is used to investigate the effectiveness and efficiency of the proposed methodology.

关键词： Compliant Assembly Inertia Effects Quality Loss Function FEA

Virus-Induced Gene Silencing Offers a Functional Genomics Platform for Studying Plant Cell Wall Formation

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Molecular Plant 2010年第5期3卷 818-833页

作者： Xiaohong Zhu sivakumar Pattathil Koushik Mazumder Amanda Brehm Michael G. Hahn S.P. Dinesh-Kumar Chandrashekhar P. Joshi Biotechnology Research Center School of Forest Resources and Environmental Science Michigan Technological University Houghton MI 49931 USA BioEnergy Science Center Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA Department of Plant Biology University of Georgia Athens GA 30602 USA Section of Plant Biology and Genome Center University of California Davis CA 95616 USA Department of Bioenergy Science and Technology Chonnam National University Gwangju 500-757 Korea

Virus-induced gene silencing （VIGS） is a powerful genetic tool for rapid assessment of plant gene functions in the post-genomic era. Here, we successfully implemented a Tobacco Rattle Virus （TRV）-based VlGS system to study functions of genes involved in either primary or secondary cell wall formation in Nicotiana benthamiana plants. A 3-week post- VIGS time frame is sufficient to observe phenotypic alterations in the anatomical structure of stems and chemical composition of the primary and secondary cell walls. We used cell wall glycan-directed monoclonal antibodies to demonstrate that alteration of cell wall polymer synthesis during the secondary growth phase of VIGS plants has profound effects on the extractability of components from woody stem cell walls. Therefore, TRV-based VlGS together with cell wall component profiling methods provide a high-throughput gene discovery platform for studying plant cell wall formation from a bioenergy perspective.

关键词： Plant cell wall VIGS cellulose xylan lignin Nicotiana.

Field and Laboratory Observations on Predation and Prey Selectivity of the Scyphomedusa Chrysaora *** in Southeast Indian Waters

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Journal of Ocean University of China 2011年第1期10卷 47-54页

作者： Govindan Kanagaraj Pazhaniyappan Ezhilarasan Pitchai Sampathkumar André C.Morandini Velayudhan pillai sivakumar Southeastern Institute of Marine Biology Thomas Nagar Department of Zoology V.O.Chidambaram College Centre of Advanced Study in Marine Biology Departamento de Zoologia Instituto de BiociênciasUniversidade de So Paulo

Chrysaora ***,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of *** ability of Chrysaora *** to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches,at least for a short *** study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water *** ingestion rate of the average-sized medusae Chrysaora *** is well balanced in nature,which in turn implies that this jellyfish is tuned for optimal utilization of available prey *** with earlier research indicates that prey escape speed is one important factor governing which prey will be captured.A full understanding of predation mechanics awaits further investigation of both predator and prey ***,because of the scarcity of long-term quantitative population data most insights have to be made ***,low abun-dance of Chrysaora *** in the water column during summer (May 2007) and the overall annual abundance seem not to con-siderably affect the zooplankton population,especially *** present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters,which is especially crucial for understanding the process of ecological recovery of coastal water environment.

关键词： predation prey selectivity jellyfish Bay of Bengal copepods

纳米贵金属插入的粘土用于催化选择性加氢反应(英文)

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催化学报 2010年第10期31卷 1200-1208页

作者： Manikandan DHANAGOPAL DURAISWAMI Divakar Rupa A.VALENTINE Mangalaraja RAMALINGA VISWANATHAN sivakumar THIRIPURANTHAGAN Catalysis Laboratory Department of Chemical Engineering A.C. College of Technology Anna University Advanced Ceramic and Nanotechnology Laboratory Department of Materials Engineering Faculty of Engineering University of Concepcion Department of Chemical Engineering Faculty of Science and Technology University of Basque Country

The use of clay minerals in the synthesis of nanosized noble metal particles to give increased catalytic activity was investigated. Nanosized platinum and ruthenium catalysts intercalated in clay (montmorillonite/hectorite) were synthesised and their catalytic activity was evaluated for the selective hydrogenation of three different α,β-unsaturated aldehydes, namely, crotonaldehyde, cinnamaldehyde, and citral, in a gas phase microreactor. The metal nano-sol was prepared by the chemical reduction of its precursor by the micellar technique in the presence of cetyl trimethyl ammonium bromide (CTAB), and the micelle stabilized metal particles were intercalated in the clay mineral by ion exchange. TEM micrographs of the catalyst particles showed that the metal particles were in the nanometre range. The average diameters of the particles were 1-25 nm. The effects of temperature, metal loading, and hydrogen flow rate on the catalytic activity and selectivity for α,β- unsaturated alcohol were studied. The results were correlated with the structural properties of the catalysts. The products formed in each reaction over the different catalysts showed that the catalysts were very active for hydrogenation, and the selectivity for the desired product, namely, α,β-unsaturated alcohol, was good. The metal catalysts intercalated in montmorillonite showed better selectivity than that in hectorite because of its higher acidity. Increased selectivity for α,β-unsaturated alcohol was observed with increased flow rate of hydrogen.

关键词： selective hydrogenation nano-particle platinum ruthenium intercalated montmorillonite or hectorite vapor phase reaction

Reduction of THD in Thirteen-Level Hybrid PV Inverter with Less Number of Switches

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Circuits and Systems 2016年第10期7卷 3403-3414页

作者： Natesan sivakumar S. Sumathi Department of EEE Jayalakshmi institute of technology Thoppur India Department of ECE Adhiyamaan College of Engineering Hosur India

Multilevel inverter (MLI) is one of the most efficient power converters which are especially suited for high power applications with reduced harmonics. MLI not only achieves high output power and is also used in renewable energy sources such as photovoltaic, wind and fuel cells. Among various topologies of MLI, this paper mainly focuses on cascaded MLI with three unequal DC sources called asymmetric cascaded MLI which reduces the number of power switches. Various modulation techniques are also reviewed in literature [1]. In this paper we focus on sinusoidal (or) multicarrier pulse width modulation (SPWM) which improves the output voltage at lower modulation index for obtaining lower Total Harmonic Distortion (THD) level. The gating signal for the 13-level hybrid inverter using SPWM technique is generated using Field Programmable Gate Array (FPGA) processor. The proposed modulation technique results in reduced percentage of THD, but lower order harmonics are not eliminated. So a new technique called Selective Harmonic Elimination (SHE) is also implemented in order to reduce the lower order harmonics. The optimum switching angles are determined for obtaining minimum THD. The performance evaluation of the proposed PWM inverter is verified using an experimental model of 13-level cascaded hybrid MLI and compared with MATLAB/SIMULINK model.

关键词： Asymmetric Cascaded Multi Level Inverter (ACMLI) Total Harmonic Distortion (THD) Sinusoidal Pulse Width Modulation (SPWM) Field Programmable Gate Array (FPGA) Selective Harmonic Elimination (SHE)

Synthesis and characterization of β-Ag_2Se andβ-AgCuSe nanoparticles via facile precipitation route

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Transactions of Nonferrous Metals Society of China 2015年第7期25卷 2241-2246页

作者： P.PRATHIBA JEYA HELAN K.MOHANRAJ G.sivakumar Department of Physics Manonmaniam Sundaranar University CISL Department of PhysicsAnnamalai University

β-Ag2 Se and β-AgCuSe nanoparticles were synthesized using AgCl precursor instead of conventional AgNO3 by simple precipitation *** was found that orthorhombic structures were obtained for both β-AgzSe and β-AgCuSe *** result shows Ag2 S as impurity while increasing the concentration of ***,the microstructural images show polyhedraland pebble-like *** band gap energy is increased for β-AgzSe owing to small crystallite *** AgC1 precursor can effectively produce pure ***,it is interesting in terms of identification of potential precursor for synthesizingβ-Ag2 Se and β-AgCuSe nanoparticles.

关键词： β-Ag2Se β-AgCuSe nanoparticle AgCl precursor precipitation method