Electronic structure, magnetic and structural properties of Ni doped ZnO nanoparticles

Kumar, S.,Vats, P.,Gautam, S.,Gupta, V.P.,Verma, K.D.,Chae, K.H.,Hashim, Mohd.,Choi, H.K. Pergamon Press 2014 Materials research bulletin Vol.59 No.-

We report structural, magnetic and electronic structural properties of Ni doped ZnO nanoparticles prepared by auto-combustion method. The prepared nanoparticles were characterized by using X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, and dc magnetization measurements. The XRD and HR-TEM results indicate that Ni doped ZnO nanoparticles have single phase nature with wurtzite lattice and exclude the presence of secondary phase. NEXAFS measurements performed at Ni L<SUB>3,2</SUB>-edges indicates that Ni ions are in +2 valence state and exclude the presence of Ni metal clusters. O K-edge NEXAFS spectra indicate an increase in oxygen vacancies with Ni-doping, while Zn L<SUB>3,2</SUB>-edge show the absence of Zn-vacancies. The magnetization measurements performed at room temperature shows that pure and Ni doped ZnO exhibits ferromagnetic behavior.

SEM Studies on the Leaf Surface of Promising Mulberry(Morus spp.) Genotypes

Singhal, B. K.,Kumar, V.,Rajan, M. V. 한국식물학회 1999 Journal of Plant Biology Vol.42 No.1

Mulberry (Morus spp.) leaf quality has a great role in silkworm rearing which in turn affects the overall silk yield. In the recent past, many varieties of mulberry have been evolved considering the morphological characters, growth, yield, and quality parameters based on bioassay. The present investigation was carried out on ten promising mulberry genotypes viz. Tr-10, K-2, S-36, S-54, S-1, V-1, Mysore local, S-13, S-34, and RFS-135 to characterize stomatal size and frequency, trichomes and idioblasts using SEM. These new parameters will provide useful information for cultivars identification as well as for selecting mulberry genotypes adapted to different eco-climatic conditions and assessing the feeding quality of leaf for silkworm rearing.

Reply to ''Comment on ''Facile chemical bath deposition of CuS nano peas like structure as a high efficient counter electrode for quantum-dot-sensitized solar cells'' by H.-J. Kim, J.-H. Kim, CH. S. S. Pavan Kumar, D. Punnoose, S.-K. Kim, C. V. V. M. Gop

Kim, H.J.,Kim, J.H.,Pavan Kumar, C.H.S.S.,Punnoose, D.,Kim, S.K.,Gopi, C.V.V.M.,Rao, S.S. Elsevier Sequoia 2015 Journal of Electroanalytical Chemistry Vol.756 No.-

Brine shrimp lethality and cytotoxicity assay of Araucaria bidwillii Hook in human carcinoma cell lines

Ahamed, KFH Nazeer,Kumar, V,Manikandan, L,Wahile, Atul M,Mukherjee, Kakali,Saha, BP,Mukherjee, Pulok K Kyung Hee Oriental Medicine Research Center 2005 Oriental pharmacy and experimental medicine Vol.5 No.1

The leaf extracts of Araucaria bidwillii Hook. (Araucariaceae) were evaluated for their cytotoxic effect in various human cancer cell lines. Preliminary investigation by brine shrimp lethality assay indicated that $LC_{50}$ value of various successive extracts were found to be less than $1000\;{\mu}g/ml$, where the ethyl acetate extract showed maximum activity of less than $100\;{\mu}g/ml$. Further cytotoxic evaluation of various leaf extracts of Araucaria bidwilli Hook was carried out in four different human cancer cell lines-acute myeloblastic leukemia (HL-60), chronic myelogenic leukemia (K-562), breast adenocarcinoma (MCF-7) and cervical epithelial carcinoma (HeLa). Cytotoxicity was assessed by trypan blue dye exclusion method and 3-(4,5-dimethyl thiazole-2yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay. From the present investigation it was found that the ethyl acetate and methanol extract of Araucaria bidwilli Hook was found to be more effective in leukemic cell lines and was less effective in MCF-7 and HeLa. The $IC_{50}$ value of the ethyl acetate extract in leukemic cell lines was found to be $28.18\;and\;34.64\;{\mu}g/ml$ and methanol extract was found to be $33.11\;&\;39.81\;{\mu}g/ml$. It can be concluded that various extract from the leaves of Araucaria bidwillii Hook. posses cytotoxic activity tested in brine shrimps and various human carcinoma cell lines.

A New Privacy Approach using Graph-EMD

CH.M.H.Saibaba,V. Uday Kumar,K. Praveenkumar,Debnath Bhattacharyya 보안공학연구지원센터 2016 International Journal of Software Engineering and Vol.10 No.7

Privacy is the word which can listen everywhere in the data mining for data preserving. It should be provided the security to the data in many ways. Privacy should be provided to the sensitive data and micro data. Hence more number of existing techniques has been introduced to provide sensitive data. Many third party service providers are showing interest to release the data which is collected for research purpose. Existing systems like k-anonymity, l-diversity and t-closeness are already existed but they can’t provide better privacy measures. Each existing method carries different types of problems. The t-closeness is the more flexible privacy model called (n,t)-closeness will provide the better privacy and usage. Proposed Closeness measures require Probability distribution that is assessed using Earth Mover’s Distance (EMD) measurement. In this paper, the graph based algorithm graph-EMD. Compare with tree-EMD, graph EMD performs more flexible. The number of unknown variables is reduced to O (N) from O (N2) of the original EMD. In this paper, with Graph-EMD is implemented and show the performance and efficiency.

Improved Thermal Stability of Green InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes with an AlGaN/GaN Short-Superlattice-Inserted Structure

Y. S. Lee,M. Senthil Kumar,T. V. Cuong,J. Y. Park,J. H. Ryu,S. J. Chung,E.-K. Suh,C.-H. Hong 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

We report an amelioration of the electrical, thermal and optical performances of green InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with AlGaN/GaN short- superlattice (SSL)-inserted structure grown using metal-organic chemical vapor deposition. Ac- cording to an atomic force microscopic study, the GaN template with the SSL-inserted structure shows a signicant reduction in pit density compared to the conventionally-grown template. The insertion of the SSL is also found to alleviate the eect of threading dislocations on the degradation of the electrical performance and promotes the stability of the K-factor and a low thermal resis- tance under a long-term acceleration test. A relatively higher optical output power is obtained for SSL-inserted InGaN/GaN green LEDs at high injection currents. We report an amelioration of the electrical, thermal and optical performances of green InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with AlGaN/GaN short- superlattice (SSL)-inserted structure grown using metal-organic chemical vapor deposition. Ac- cording to an atomic force microscopic study, the GaN template with the SSL-inserted structure shows a signicant reduction in pit density compared to the conventionally-grown template. The insertion of the SSL is also found to alleviate the eect of threading dislocations on the degradation of the electrical performance and promotes the stability of the K-factor and a low thermal resis- tance under a long-term acceleration test. A relatively higher optical output power is obtained for SSL-inserted InGaN/GaN green LEDs at high injection currents.

Natural history of relapsed myeloma, refractory to immunomodulatory drugs and proteasome inhibitors: a multicenter IMWG study

Kumar, S K,Dimopoulos, M A,Kastritis, E,Terpos, E,Nahi, H,Goldschmidt, H,Hillengass, J,Leleu, X,Beksac, M,Alsina, M,Oriol, A,Cavo, M,Ocio, E M,Mateos, M V,O'Donnell, E K,Vij, R,Lokhorst, H M,van de Do Macmillan Publishers Limited, part of Springer Nat 2017 Leukemia Vol.31 No.11

<P>Introduction of new myeloma therapies offers new options for patients refractory to immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs). In this multicenter study, patients with relapsed multiple myeloma, who have received at least three prior lines of therapy, are refractory to both an IMiD (lenalidomide or pomalidomide) and a PI (bortezomib or carfilzomib), and have been exposed to an alkylating agent were identified. The time patients met the above criteria was defined as time zero (T-0). Five hundred and forty-three patients diagnosed between 2006 and 2014 were enrolled in this study. Median age at T-0 was 62 years (range 31-87); 61% were males. The median duration between diagnosis and T-0 was 3.1 years. The median number of lines of therapy before T-0 was 4 (range 3-13). The median overall survival (OS) from T-0 for the entire cohort was 13 (95% confidence interval (CI) 11, 15) months. At least one regimen recorded after T-0 in 462 (85%) patients, with a median (95% CI) progression-free survival and OS from T-0 of 5 (4, 6), and 15.2 (13, 17) months, respectively. The study provides the expected outcome of relapsed multiple myeloma that is refractory to a PI and an IMiD, a benchmark for comparison of new therapies being evaluated.</P>

Protective effect of Asystasia gangetica reduced oxidative damage in the small intestine of streptozotocin-induced diabetic rats

Kumar, K. Asok,Umamaheswari, M.,Sivashanmugam, A.T.,Subhadradevi, V.,Somanathan, S.S.,Ravi, T.K. Kyung Hee Oriental Medicine Research Center 2009 Oriental pharmacy and experimental medicine Vol.9 No.4

Oxidative stress plays an important role in the pathogenesis of various diabetic complications and small intestine is vulnerable to damage resulting in morphological and functional changes. In this study, the effects of Asystasia gangetica leaf extract (AGLE) on oxidative stress status in small intestine of diabetic rats were examined. The leaves of Asystasia gangetica was extracted with 70% ethanol. Oral administration of AGLE once daily (100 mg/kg and 200 mg/kg b.w.) for 28 days to diabetic rats significantly (P < 0.05) increased antioxidant levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione, GSSH, carbohydrate metabolizing enzyme, glucose-6-phosphate dehydrogenase. The increased levels of protein carbonyl content, lipid peroxidation and xanthine oxidase/xanthine dehydrogenase in diabetic rats were reverted back to near normal levels on treatment with AGLE. Both doses of AGLE offered significant activity (P < 0.01) against oxidative damage and were comparable with standard, glibenclamide. The results revealed the occurrence of oxidative stress in small intestine during diabetes and suggest the potential of AGLE as an antioxidant in protecting the tissue defense system against oxidative damage in streptozotocin-induced diabetes.

Transmission Security Enhancement under (N−1) Contingency Conditions with Optimal Unifed Power Flow Controller and Renewable Energy Sources Generation

K. V. Kumar Kavuturu,P. V. R. L. Narasimham 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

Introduction Transmission system security management under (N−1) line contingency is one of the typical and essential tasks in power system operation and control. This paper examines the impact of the optimal unifed power fow controller (OUPFC) and renewable energy sources (RES) on the severity of (n−1) line contingency on transmission system security. Materials and methods To test the performance of OUPFC device under single line contingency conditions, an optimal power fow (OPF) based multi-objective function is formulated using real power loss and line collapse proximity indicator (LCPI). Primarily, the optimal location of the OUPFC is determined using LCPI index and then (n−1) contingency analysis is performed by considering OUPFC device at diferent RES generation levels. Here, the control variables of OUPFC, tapchangers, VAr injections, output power of conventional energy sources (CES), bus voltages and bus angles are optimized with two diferent variants of the cuckoo search algorithm (CSA) namely (1) dynamically increasing switching parameter in power of three (CSA1) and (2) exponentially increasing switching parameter (CSA2). Conclusion The simulation results of various case studies on a standard IEEE-30 bus test system have shown the superiority of CSA2 in solving the multi-objective, non–linear complex optimization problem over CSA1 and time-varying acceleration coefcient-particle swarm optimization (TVAC-PSO). Also, the ability of OUPFC for managing the impact of (n−1) line contingency and variable RES generation is shown in terms of decreased real power loss, improved voltage profle and enhanced security margin.

Dazzling red emission from TiO₂ nanoparticles impregnated co-doped Gd³⁺+Eu³⁺: PVA polymer nanocomposites for photonic applications

Kumar, K.N.,R., P.,L., V.,Kang, M. Korean Society of Industrial and Engineering Chemi 2017 Journal of industrial and engineering chemistry Vol.45 No.-

<P>Red emission was obtained from rare earth doped polymer nanocomposites, namely, composites of polyvinyl-alcohol (PVA) co-doped with Gd3+ and Eu3+ and embedded with TiO2 nanoparticles (TiO2NP), under ultraviolet (UV) excitation. We successfully synthesized Eu3+: PVA, Gd3+: PVA, (Gd3+ + Eu3+): PVA, and (Gd3++ Eu3+ +TiO2NP): PVA films by solution casting method. From X-ray diffraction patterns and Fourier-transform infrared spectral profiles, the structural details of the films and the ion-polymer interaction mechanism responsible for their formation were systematically analyzed. The thermal stability and decomposition dynamics of the prepared samples were evaluated by thermogravimetry and differential thermal analysis. Pertinent optical absorption bands related to Eu3+ and Gd3+ ions in the polymer composites were observed and assigned to the corresponding electronic transitions. The PVA film containing different concentrations of the Eu3+ dopant displayed red emission at 618 nm (D-5(0) -> F-7(2)) under UV excitation at 396 nm (F-7(0) -> L-5(6)). Upon co-doping with Gd3+ to form the (Gd3+ + Eu3+): PVA film, it exhibited red emission that was stronger than that from the singly doped Eu3+: PVA film under 270 nm excitation because of the energy transfer from Gd3+ to Eu3+ ions. After the TiO2 nanoparticles were evenly dispersed in the co-doped (Gd3+ + Eu3+): PVA films, the photoluminescence properties were remarkably enhanced and prominent red emission was observed under 274 nm excitation. The red emission of Eu3+ was significantly enhanced through an efficient energy-transfer process from the Gd3+ ions to Eu3+ ions and from the TiO2 nanoparticles to Eu3+ ions. A possible energy-transfer mechanism was clearly demonstrated by several fluorescent methods and lifetime decay dynamics. Based on the above results, these polymer composite films are promising candidates for red luminescent photonic devices. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>