Strong elevational trends in soil bacterial community composition on Mt. Halla, South Korea

Singh, D.,Lee-Cruz, L.,Kim, W.S.,Kerfahi, D.,Chun, J.H.,Adams, J.M. Pergamon Press ; Elsevier Science Ltd 2014 Soil biology & biochemistry Vol.68 No.-

Elevational trends in the ecology of macroorganisms have been studied extensively; by contrast very little is known of such trends in microbial diversity. Previous studies on soil bacteria have found either a diversity decline, a 'peak' in mid altitudes, or no trend with increasing elevation. Here we studied bacterial diversity and community composition in relation to elevation on Mt. Halla, Jeju Island, South Korea, a massive shield volcano. Samples were taken along two transects, from 100 m.a.s.l. to the summit at 1950 m.a.s.l., at elevational intervals of 200 m. PCR-amplified soil DNA for the bacterial 16S rRNA gene targeting V1 to V3 region was 454-pyrosequenced, and taxonomically classified against EzTaxon-e database. Elevation was the best predictor of variation in bacterial community composition along the two transects, even when considering other soil parameters. Elevation was itself highly correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), suggesting that soil bacterial community composition on Mt. Halla is more strongly affected by climate than by geochemical or soil textural factors. The two transects showed certain consistent differences in bacterial phyla composition, with one transect having significantly higher abundance of Planctomycetes and Gemmatimonadetes than the other. Certain other phyla (e.g. Acidobacteria) also showed striking trends in abundance with elevation, but the trends differed between the two transects. Bacterial diversity and richness were also most strongly correlated with elevation, MAT and MAP, although soil pH explained a part of the variation. Moreover, vegetation cover type, irrespective of elevation, had an effect on soil bacterial diversity and richness. We found a 'dip' in diversity at lower mid elevations (700-1300 m) in both transects; a trend which has not been found before. Our results, when compared with other studies, emphasize that no simple rule can be applied to mountain systems in general, but that climate itself is a major influence on community composition.

Synthesis, magnetic and Mossbauer spectroscopic studies of Cr doped lithium ferrite nanoparticles

Srivastava, M.,Layek, S.,Singh, J.,Das, A.K.,Verma, H.C.,Ojha, A.K.,Kim, N.H.,Lee, J.H. Elsevier Sequoia 2014 JOURNAL OF ALLOYS AND COMPOUNDS Vol.591 No.-

Lithium-based ferrites are promising and potential magnetic materials for microwave applications. They possess a spinel (AB<SUB>2</SUB>O<SUB>4</SUB>) type crystal structure, where the distributions of metal cations over the tetrahedral (A) and octahedral (B) voids play a crucial role for exhibiting different physical properties. Among various parameter of synthesis, pH is an important factor that influences the cation distribution over A and B voids, overall growth of the nanoparticles and different physical properties. In the present work single phase Cr substituted lithium ferrite nanoparticles have been synthesized by the sol-gel method at different pH. The phase identification and crystallite size have been probed by X-ray diffraction studies. The crystallite size changes by 44.2-48.8nm upon varying the pH from 3.5 to 11.5. In order to investigate the cations distribution at A/B sites, Mossbauer spectroscopic measurements were done. The values of magnetic hyperfine field obtained from the Mossbauer data for the A and B sites are ~49.5T and 51T, respectively. Moreover, it is observed that the area ratio of B site to A site increases with increasing the pH. This observation further suggests that the B site is more preferable for Fe<SUP>3+</SUP> cations at higher pH than the A site. The magnetic parameter such as saturation magnetization (M<SUB>s</SUB>), remanent magnetization (M<SUB>r</SUB>), coercive field (H<SUB>C</SUB>) and squareness (S) are determined by vibrating sample magnetometer (VSM) measurements, which show a consistent increase with increasing pH. The reason for the variation in magnetic properties has been explained on the basis of increased Fe<SUP>3+</SUP> cation occupancies at the B site and size effect, which is well supported by Mossbauer spectroscopic and XRD studies.

2, 4-Thiazolidindion Induced Plasticity of Myoblast (C2C12) and Satellite Cells (Porcine) - A Comparative Study

Singh, N.K.,Chae, H.S.,Hwang, I.H.,Yoo, Y.M.,Ahn, C.N.,Lee, H.J.,Park, H.J.,Chung, H.Y. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.7

This study was conducted to determine the difference between satellite cells (porcine) and myoblasts (C2C12) in their differentiation under the influence of 2, 4-thiazolidindion. C2C12 myoblast cells and porcine satellite cells (isolated from 10 d old $Landrace{\times}Duroc$ piglets) were grown to absolute confluency. Post confluent cells (day 0) were further exposed to adipogenic induction medium along with 2, 4-thiazolidindion ($8{\mu}M$) for 2 d. Thereafter, cells were exposed to 2, 4-thiazolidindion alone every 2 d till day 10 and analysed. The control was cultured in differentiation medium without any treatment. Increased (p<0.05) expression of transcriptional factors i.e. C/EBP-${\alpha}$ and PPAR-${\gamma}$ and transition of cells to adipocyte morphology was noticed from 2 d and 4 d onwards in satellite cells (Porcine) and myoblasts (C2C12) respectively. Myogenesis was observed to be suppressed completely in case of satellite cells compared to myoblasts in response to 2, 4-thiazolidindion. Pax-7 (transcriptional factor) appeared as a sole entity to satellite cells only, as it was not identified in case of myoblasts. Although both the cells were converting to adipoblasts, the degree of their conversion was different in response to 2, 4-thiazolidindion. Therefore, the hypothesis that satellite cells contribute various domains to the growing myoblasts appeared obscured and found to be dependent on the proliferative energy/or degree of fusion. However, it revealed satellite cells as currency to myoblasts/muscle.

Optical characterization, absorption and upconversion luminescence in Er³⁺and Er³⁺/Yb³⁺doped In₂O₃ phosphor

Singh, Vijay,Seshadri, M.,Singh, N.,Pathak, M.S.,Kumaran, R. Senthil,Choi, Yong-Keun,Singh, Pramod K.,Dhoble, S.J.,Srivastava, Anoop K. Elsevier 2016 Journal of luminescence Vol.176 No.-

<P><B>Abstract</B></P> <P>Combustion derived In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>, co-doped with Yb<SUP>3+</SUP>phosphor powders have been prepared. Powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and Fourier transform infrared spectroscopy methods are used to characterize the prepared phosphor powders. The intensity parameters (<I>Ω<SUB>λ</SUB> </I>, <I>λ</I>=2, 4 and 6), radiative transition probabilities (<I>A<SUB>R</SUB> </I>), radiative lifetime (<I>τ<SUB>R</SUB> </I>) and branching ratios (<I>β</I>) of certain emission transition of Er<SUP>3+</SUP>ions for In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>and In<SUB>2</SUB>O<SUB>3</SUB>:Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>phosphors have been estimated in the framework of the model given by Judd–Ofelt. Upon excitation at 978nm, upconversion luminescence properties of Er<SUP>3+</SUP>and Er<SUP>3+</SUP>/Yb<SUP>3+</SUP>doped In<SUB>2</SUB>O<SUB>3</SUB> phosphors are investigated. The results obtained from optical study confirm the existence of an effective Yb<SUP>3+</SUP>to Er<SUP>3+</SUP>energy transfer process and it also predict possible mechanisms to populate the <SUP>4</SUP>S<SUB>3/2</SUB> and <SUP>4</SUP>F<SUB>9/2</SUB> levels. The possible upconversion mechanisms are discussed for Er<SUP>3+</SUP>and Yb<SUP>3+</SUP>ions with energy level diagram.</P>

Investigation of ultraviolet emitting Gd doped Sr₂MgSi₂O₇ phosphors

Singh, Vijay,Sivaramaiah, G.,Singh, N.,Pathak, M.S.,Rao, J.L.,Jirimali, H.D.,Natarajan, V. Elsevier 2018 Optik Vol.169 No.-

<P><B>Abstract</B></P> <P>This article deals with the ultraviolet (UV)-emitting gadolinium (Gd)-doped strontium magnesium disilicate (Sr<SUB>2</SUB>MgSi<SUB>2</SUB>O<SUB>7</SUB>) phosphors. A series of the Gd-doped Sr<SUB>2</SUB>MgSi<SUB>2</SUB>O<SUB>7</SUB> phosphors were prepared using a sol-gel method. The powders were well characterized using the X-ray powder diffraction (XRPD) and scanning electron microscope (SEM) techniques. The emission measurements upon a specific UV-light excitation (273 nm) showed the emission characteristics of the Gd<SUP>3+</SUP> that are due to the <SUP>6</SUP>P<SUB>J/2</SUB> → <SUP>8</SUP>S<SUB>7/2</SUB> transition. EPR spectra of the prepared samples indicated the presence of Gd<SUP>3+</SUP> ions in low symmetry sites in this sample.</P>

^[C][W]Rice Mitogen-Activated Protein Kinase Interactome Analysis Using the Yeast Two-Hybrid System

Singh, R.,Lee, M.-O.,Lee, J.-E.,Choi, J.,Park, J.H.,Kim, E.H.,Yoo, R.H.,Cho, J.-I.,Jeon, J.-S.,Rakwal, R. AMERICAN SOCIETY OF PLANT BIOLOGISTS 2012 PLANT PHYSIOLOGY - Vol.160 No.1

Correlation between the dielectric properties and local electronic structure of copper doped calcium titanate

Singh, J.P.,Gautam, S.,Kumar, P.,Tripathi, A.,Chen, J.M.,Chae, K.H.,Asokan, K. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.572 No.-

Copper-doped calcium titanate (Cu<SUB>x</SUB>Ca<SUB>1-x</SUB>TiO<SUB>3</SUB>, x=0.0, 0.01, 0.02 and 0.03) ceramic system was synthesized using solid state reaction method. X-ray diffraction and Raman spectroscopic studies reveal the presence of Pbnm space group in the samples. The particle size estimated from scanning electron micrograph changes from 235nm to 6.5μm with copper doping, however crystallite size remain almost constant within experimental error. The dielectric study performed on these samples indicates an increase in the value of dielectric constant with Cu doping. The drastic change in the value of dielectric constant of the samples has been attributed to the change in microstructure. Local electronic structure deduced from X-ray absorption near edge structure reveals no distortion at TiO<SUB>6</SUB> octahedra and reduction in O(2p) and Ca(4sp) hybridized states with increase of Cu<SUP>2+</SUP> doping.

Gadolinium-Activated CaZr4O9 Ultraviolet-B-Emitting Phosphor: A Luminescence and EPR Study

Singh, V.,Singh, N.,Watanabe, S.,Gundu Rao, T. K.,Pathak, M. S.,Srivastava, A. K.,Singh, P. K.,Dhoble, S. J. Springer Science + Business Media 2017 Journal of electronic materials Vol.46 No.4

EPR and optical properties of green emitting Mn-doped BaMgAl10O17 nano-phosphors prepared by a combustion reaction

Singh, V.,Mohapatra, M.,Sivaramaiah, G.,Rao, J. L.,Singh, N.,Gao, H.,Li, J.,Srivastava, A. K.,Jirimali, H. D.,Dhoble, S. J. Springer Science + Business Media 2016 Journal of materials science Materials in electron Vol.27 No.4

<P>Manganese doped BaMgAl10O17 nano-phosphors were synthesized by a low-temperature initiated, gas producing solution combustion process. Phase purity of the prepared phosphors was determined using X-ray diffraction technique. Dynamic light scattering technique was used to estimate the average particle size of the synthesized products. Scanning electron microscopy technique was used to study the morphology of the prepared samples. Fourier transform infrared spectroscopy was used to ascertain the formation of the aluminate host. UV-visible absorption spectroscopy showed band maxima at around 260 nm and intense band maxima at around 216 nm. Electron paramagnetic resonance experiments for the system were carried out to understand the site occupancy of the Mn ions. The photoluminescence excitation and emission spectra suggested the stabilisation of Mn ions in Td geometry. From the colour characterisation of the system it was found out that the system can be effective as a green phosphor material with wide range of applications.</P>

3',5-dihydroxy-3,4',7-trimethoxyflavone-induces ER-stress-associated HCT-116 programmed cell death via redox signaling

Singh, M.P.,Han, J.,Kang, S.C. Masson Pub. USA, Inc 2017 BIOMEDICINE AND PHARMACOTHERAPY Vol.88 No.-

<P>Quercetin, a well cognized bioactive flavone possessing great medicinal value, has limited usage. The rapid gastrointestinal digestion of quercetin is also a major obstacle for its clinical implementation due to low bioavailability and poor aqueous solubility. 30,5-dihydroxy-3,40,7-trimethoxyflavone (DTMF), a novel semi-synthetic derivative of quercetin, is known to modulate several biological activities. Therefore, in the present study we examined the cytotoxic mechanism of DTMF in concentration-dependent manner (25, 50, and 100 mu M; 24 h) against HCT-116 human colon carcinoma cells. The cytotoxic potential of DTMF was characterized based on deformed cell morphology, increased ROS accumulation, loss of mitochondrial membrane potential (Delta psi m), increased mitochondrial mass, chromatin condensation, and typical DNA-fragmentation in HCT-116 cells. The results showed that DTMF-induced enhanced ROS production at higher concentration (100 mu M) as evidenced by upregulated expression of ER stress and apoptotic proteins with concomitant increase in PERK, CHOP, and JNK levels, when compared to N-acetyl cysteine (NAC, ROS inhibitor) treated HCT-116 cells, which depicts that DTMF might act as a crucial mediator of apoptosis signaling. Collectively, our results suggest that DTMF stimulates ROS-mediated oxidative stress, which in turn induces PERK-CHOP and JNK pathway of apoptosis to promote HCT-116 cell death. (C) 2017 Elsevier Masson SAS. All rights reserved.</P>