Isolation of a New Microsporidian sp. (NIK-5hm) forming Spores within the Haemocytes of Silkworm, B. mori L.

Selvakumar T.,Nataraju B.,Chandrasekharan K.,Sharma S. D.,Balavenkatasubbaiah M.,Sudhakara Rao P.,Thiagarajan V.,Dandin S. B. Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.11 No.1

While observing silkworm larval samples received from field, microsporidian spores formed within the haemocytes of silkworm haemolymph were observed. The spores of microsporidian sp. were purified and characterized for morphological characters viz., size, shape as well as serological affinity with different Nosema spp. (M$_{11}$ and M$_{12}$). The infectivity of the isolated spores to silkworm was also studied. The microsporidian sp. was found to be highly pathogenic to silkworm, B. mori. The isolated microsporidian sp. was designated as NIK-5hm, which formed ovocylindrical spore in the haemocytes of silkworm and differed in spore size (length, 4.55 $\mu$m & width, 2.10 $\mu$m) and shape from Nosema bombycis (NIK-ls), NIK-2r (Nosema sp. Mysore [3.6 & 2.8 $\mu$m]), NIK-3h (Nosema sp. M$_{11}$ [3.8 & 1.8 $\mu$m]), NIK-4m (Nosema sp. M$_{12}$ [5.0 & 2.1 $\mu$m]) and Lb$_{ms}$ (Nosema sp. in Lamerine breed of silkworm [4.36 & 2.14]). In immonological test (Latex agglutination test), the isolated microsporidian spores did not react with antibody sensitized latex particles of N. bombycis, M$_{11}$, M$_{12}$ and Lb$_{ms}$ and thus are different type of microsporidian sp., parasitic to silkworm, Bombyx mori L.

Investigation on the local electronic/atomic structure properties using XANES/EXAFS and photocatalyst application of Zr_1-xCu_xO₂ (0 @? x @? 0.2)

Sharma, A.,Varshney, M.,Chae, K.H.,Shin, H.J.,Won, S.O. Elsevier 2016 Current Applied Physics Vol.16 No.10

<P>We investigated local electronic/atomic structure properties by using X-ray absorption spectroscopy and demonstrated the photocatalyst application of Zr1-xCuxO2 (0 <= x <= 0.2) samples. X ray diffraction (XRD) results revealed the amorphous nature of the samples; however, transmission electron microscopy (TEM) depicted the formation of < 2 nm sized particles in all of the samples. Local electronic structure was investigated by X-ray absorption near edge structure (XANES) at O K-edge, Zr K-edge and Cu K-edge. The O K-edge XANES suggested strong hybridization of s-p-d orbitals upon Cu doping. The Cu K-edge XANES confirmed +1 valence state of Cu (Cu+1) in all of the Cu doped ZrO2 samples. Extended X-ray absorption fine structure (EXAFS) analysis at the Zr K-edge nullifies the formation of trivial phases and confirms the local monoclinic structure in all of the samples. Photocatalyst properties of the samples were investigated by monitoring the net degradation in the methyl orange dye aqueous solution under the UV light irradiation. The Cu doped ZrO2 samples exhibited superior photo-catalyst properties over the undoped ZrO2. (C) 2016 Elsevier B.V. All rights reserved.</P>

Comparative study of finite element analysis and generalized beam theory in prediction of lateral torsional buckling

Sharma, Shashi Kant,Kumar, K.V. Praveen,Akbar, M. Abdul,Rambabu, Dadi Techno-Press 2022 Advances in materials research Vol.11 No.1

In the construction industry, thin-walled frame elements with very slender open cross-sections and low torsional stiffness are often subjected to a complex loading condition where axial, bending, shear and torsional stresses are present simultaneously. Hence, these often fail in instability even before the yield capacity is reached. One of the most common instability conditions associated with thin-walled structures is Lateral Torsional Buckling (LTB). In this study, a first order Generalized Beam Theory (GBT) formulation and numerical analysis of cold-formed steel lipped channel beams (C80×40×10×1, C90×40×10×1, C100×40×10×1, C80×40×10×1.6, C90×40×10×1.6 and C100×40×10×1.6) subjected to uniform moment is carried out to predict pure Lateral Torsional Buckling (LTB). These results are compared with the Finite Element Analysis of the beams modelled with shell elements using ABAQUS and analytical results based on Euler's buckling formula. The mode wise deformed shape and modal participation factors are obtained for comparison of the responses along with the effect of varying the length of the beam from 2.5 m to 10 m. The deformed shapes of the beam for different modes and GBTUL plots are analyzed for comparative conclusions.

X-ray absorption spectroscopy study and photocatalyst application of CuO and Cu_0.9Ti_0.1O nanoparticles

Sharma, A.,Varshney, M.,Ha, T.K.,Chae, K.H.,Shin, H.J. Elsevier 2015 Current Applied Physics Vol.15 No.10

We report detailed investigations on the electronic structure and photocatalyst application of CuO and Cu<SUB>0.9</SUB>Ti<SUB>0.1</SUB>O nanoparticles (NPs). The NPs were prepared by co-precipitation method and subsequent annealing. Crystal structure and morphology of the NPs were investigated by synchrotron X-ray diffraction and high resolution transmission electron microscope, respectively. The local atomic structure around the Cu atoms was investigated by the extended X-ray absorption fine structure (EXAFS) at the Cu K-edge. Electronic structure determination was done using near edge X-ray absorption fine structure (NEXAFS) at the O K-edge, Cu L-edge, Cu K-edge and Ti L-edge. From the structural and electronic structure investigations, it is inferred that the Ti substitutes the Cu in CuO lattice without forming any secondary phases and the valence state of Cu is not affected by the Ti substitution; however the Cu - O bond length is found to be shorten in the Ti doped sample. As prepared NPs exhibit excellent photocatalyst application toward the degradation of methyl orange (MO) and potassium dichromate (PD) pollutant dyes under the visible light irradiation. The mechanism of the photodegradation of MO and PD pollutants, by the smaller sized CuO and larger sized Cu<SUB>0.9</SUB>Ti<SUB>0.1</SUB>O NPs, is briefly discussed.

X-ray absorption spectroscopy investigations on electronic structure and luminescence properties of Eu:SnO₂-SnO nanocomposites

Sharma, A.,Varshney, M.,Shin, H.J.,Chae, K.H.,Won, S.O. Elsevier 2016 CURRENT APPLIED PHYSICS Vol.16 No.10

<P>Tin oxide nanostructures are nontoxic in nature and biocompatible. However, they exhibit weak emission characteristics that limit their applications in cellular and biology fields. Therefore, it is important to enhance luminescence properties in this oxide and establish a relationship between the local electronic structure and emission characteristics. In this report, we demonstrate significant advancement in the photoluminescence (PL) properties in the Eu incorporated SnO2-SnO nanocomposites. Eu: SnO2-SnO nanocomposites were synthesized by chemical precipitation method. X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and PL measurements were performed to investigate the structural, electronic structure and emission properties of the samples. Eu3+ ions, as confirmed by the Eu M-5,M-4-edge XANES studies, lead to defect formation and local electronic structural perturbation in the nanocomposites. The O K-edge and Sn M-5,M-4-edge XANES studies confirm a net decrease in the hybridization of O 2p and Sn 5s/5p states and formation of Sn defects, upon Eu doping. Significant enhancement in the Eu3+ related interband transitions (D-5(0)-F-7(J); J = 0,1,2,3,4) is achieved upon increasing the Eu concentrations, indicating synthesis of emission characteristic rich SnO2-SnO nanocomposites. (C) 2016 Elsevier B.V. All rights reserved.</P>

MDP Feature Extraction Technique for Offline Handwritten Gurmukhi Character Recognition

Munish Kumar,M. K. Jindal,R. K. Sharma 한국산학기술학회 2013 SmartCR Vol.3 No.6

Character recognition is intricate work because of the various writing styles of different individuals. Most of the published work on handwritten character recognition problems deals with statistical features, and a few works deal with structural features, in general, and Gurmukhi script, in particular. In the present work, we propose a methodology for offline handwritten Gurmukhi character recognition by using a modified division points (MDP) feature extraction technique. We also compare this technique with other recently used feature extraction techniques, namely zoning features, diagonal features, directional features, intersection and open end points features, and transition features. To select a representative set of features is the most significant task for a character recognition system. After feature extraction, the classification stage makes use of the features extracted in the previous stage to recognize the character. In this work, we used linear-support vector machines (linear-SVM), k-nearest neighbor (k-NN), and multilayer perceptron (MLP) classifiers for recognition. For experimental analysis, we used 10,500 samples of the isolated, offline, handwritten, basic 35 akhars of Gurmukhi script. The proposed system achieved a maximum recognition accuracy of 84.57%, 85.85% and 89.20% with linear-SVM, MLP and k-NN classifiers, respectively, with a five-fold cross validation technique.

PCA-based Offline Handwritten Character Recognition System

Munish Kumar,M. K. Jindal,R. K. Sharma 한국산학기술학회 2013 SmartCR Vol.3 No.5

Principal component analysis (PCA) has been used widely in pattern recognition to reduce the extent of the data. In this paper, we explore using this technique to recognize offline handwritten Gurmukhi characters, and a system for offline handwritten Gurmukhi character recognition using PCA is proposed. The system first prepares a skeleton of the character so that meaningful feature information about the character can be extracted. For classification, we used k-nearest neighbor, Linear-SVM, polynomial-SVM and RBF-SVM based approaches and combinations of these approaches. In this work, we collected 16,800 samples of isolated offline handwritten Gurmukhi characters. These samples were divided into three categories. In category 1 (5600 samples), each Gurmukhi character was written 100 times by a single writer. In category 2 (5600 samples), each Gurmukhi character was written 10 times by 10 different writers, and in category 3 (5600 samples), each Gurmukhi character was written by 100 different writers. The set of the basic 35 akhars of Gurmukhi has been considered here. A partitioning strategy for selecting the training and testing patterns is also explored in this work. We used zoning, diagonal, directional, transition, intersection and open end point, parabola curve fitting?based and power curve fitting?based feature extraction in order to find the feature set for a given character. The proposed system achieves a recognition accuracy of 99.06% in category 1, 98.73% in category 2 and 78.30% in category 3.

Isolation of a New Microsporidian sp. (NIK-5hm) forming Spores within the Haemocytes of Silkworm, B. mori L.

( T. Selvakumar ),( B. Nataraju ),( K. Chandrasekharan ),( S. D. Sharma ),( M. Balavenkatasubbaiah ),( P. Sudhakara Rao ),( V. Thiagarajan ),( S. B. Dandin ) 한국잠사학회 2005 International Journal of Industrial Entomology Vol.11 No.1

While observing silkworm larval samples received from field, microsporidian spores formed within the haemocytes of silkworm haemolymph were observed. The spores of microsporidian sp. were purified and characterized for morphological characters viz., size, shape as well as serological affinity with different Nosema spp. (M11 and M12). The infectivity of the isolated spores to silkworm was also studied. The microsporidian sp. was found to be highly pathogenic to silkworm, B. mori. The isolated microsporidian sp. was designated as NIK-5hm, which formed ovocylindrical spore in the haemocytes of silkworm and differed in spore size (length, 4.55 μm & width, 2.10 μm) and shape from Nosema bombycis (NIK-1s), NIK-2r (Nosema sp. Mysore [3.6 & 2.8 μm]), NIK-3h (Nosema sp. M11 [3.8 & 1.8 μm]), NIK-4m (Nosema sp. M12 [5.0 & 2.1 μm]) and Lb㎳ (Nosema sp. in Lamerine breed of silkworm [4.36 & 2.14]). In immonological test (Latex agglutination test), the isolated microsporidian spores did not react with antibody sensitized latex particles of N. bombycis, M11, M12 and Lb㎳ and thus are different type of microsporidian sp., parasitic to silkworm, Bombyx mori L.

Mechanistic insights into the interaction between energetic oxygen ions and nanosized ZnFe₂O₄: XAS-XMCD investigations

Singh, Jitendra Pal,Kaur, Baljeet,Sharma, Aditya,Kim, So Hee,Gautam, Sanjeev,Srivastava, Ramesh Chandra,Goyal, Navdeep,Lim, Weol Cheol,Lin, H.-J.,Chen, J. M.,Asokan, K.,Kanjilal, D.,Won, Sung Ok,Lee, The Royal Society of Chemistry 2018 Physical Chemistry Chemical Physics Vol.20 No.17

<P>The interactions of energetic ions with multi-cation compounds and their consequences in terms of changes in the local electronic structure, which may facilitate intriguing hybridization between O 2p and metal d orbitals and magnetic ordering, are the subject of debate and require a deep understanding of energy transfer processes and magnetic exchange mechanisms. In this study, nanocrystals of ZnFe2O4 were exposed to O<SUP>7+</SUP> ions with an energy of 100 MeV to understand, qualitatively and quantitatively, the metal-ligand field interactions, cation migration and magnetic exchange interactions by employing X-ray absorption fine structure measurements and X-ray magnetic circular dichroism to get deeper mechanistic insights. Nanosized zinc ferrite nanoparticles (NPs) with a size of ∼16 nm synthesized in the cubic spinel phase exhibited deterioration of the crystalline phase when 100 MeV O<SUP>7+</SUP> ions passed through them. However, the size of these NPs remained almost the same. The behaviour of crystal deterioration is associated with the confinement of heat in this interaction. The energy confined inside the nanoparticles promotes cation redistribution as well as the modification of the local electronic structure. Prior to this interaction, almost 42% of Zn<SUP>2+</SUP> ions occupied AO4 tetrahedra; however, this value increased to 63% after the interaction. An inverse effect was observed for metal ion occupancies in BO6 octahedra. The L-edge spectra of Fe and Zn reveal that the spin and valence states of the metal ions were not affected by this interaction. This effect is also supported by K-edge measurements for Fe and Zn. The t2g/eg intensity ratio in the O K-edge spectra decreased after this interaction, which is associated with detachment of Zn<SUP>2+</SUP> ions from the lattice. The extent of hybridization, as estimated from the ratio of the post-edge to the pre-edge region of the O K-edge spectra, decreased after this interaction. The metal-oxygen and metal-metal bond lengths were modified as a result of this interaction, as determined from extended X-ray absorption fine structure measurements. These measurements further support the observation of cation migration from AO4 tetrahedra to AO6 octahedra and <I>vice versa</I>. The Fe L-edge magnetic circular dichroism spectra indicate that Fe<SUP>3+</SUP> ions occupying sites in AO4 tetrahedra and BO6 octahedra exhibited antiferromagnetic-like ordering prior to this interaction. The NPs that interacted with energetic O ions displayed a different kind of magnetic ordering.</P>

Structural and magnetic properties of chemically synthesized Fe doped ZnO

Kumar, Shalendra,Kim, Y. J.,Koo, B. H.,Sharma, S. K.,Vargas, J. M.,Knobel, M.,Gautam, S.,Chae, K. H.,Kim, D. K.,Kim, Y. K.,Lee, C. G. American Institute of Physics 2009 JOURNAL OF APPLIED PHYSICS - Vol.105 No.7

<P>We report on the synthesis of Fe-doped ZnO with nominal composition of Zn0.99Fe0.01O by using a coprecipitation method. X-ray diffraction and selective area electron diffraction studies reveal a single phase wurtzite crystal structure without any secondary phase. Field emission transmission electron microscopy measurements infer that Zn0.99Fe0.01O have nanorod-type microstructures. Magnetic hysteresis measurement performed at different temperatures show that Zn0.99Fe0.01O exhibits a weak ferromagnetic behavior at room temperature. A detailed investigation of the electronic and local structure using O K-, Fe L-3,L-2 near edge x-ray absorption fine structure suggests that Fe is substituting Zn in ZnO matrix and is in Fe3+ state. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3073933]</P>