Structural and magnetic study of a dilute magnetic semiconductor: Fe doped CeO2 nanoparticles

This paper reports the effect of Fe doping on the structure and room temperature ferromagnetism of CeO2 nanoparticles. X-ray diffraction and selective area electron diffraction measurement reflects that Ce1-xFexO2 (x = 0.0 - 0.07) nanoparticles exhibit single phase nature with cubic structure and none of the sample showed the presence of any secondary phase. The mean particle size calculated by using a transmission electron microscopy measurement was found to increase with increase in Fe content. DC magnetization measurements performed at room temperature indicates that all the samples exhibit ferromagnetism. The saturation magnetic moment has been found to increase with an increase in the Fe content.Comment: 16 Pages, 5 figure, 1 Table, Accepted in JN

Room temperature ferromagnetism in chemically synthesized ZnO rods

We report structural and magnetic properties of pure ZnO rods using X-ray diffraction (XRD), magnetization hysteresis (M-H) loop and near edge x-ray fine structure spectroscopy (NEXAFS) study at O K edge. Sample of ZnO was prepared by co-precipitation method. XRD and selective area electron diffraction measurements infer that ZnO rods exhibit a single phase polycrystalline nature with wurtzite lattice. Field emission transmission electron microscopy, field emission scanning electron microscopy micrographs infers that ZnO have rod type microstructures with dimension 200 nm in diameter and 550 nm in length. M-H loop studies performed at room temperature display room temperature ferromagnetism in ZnO rods. NEXAFS study reflects absence of the oxygen vacancies in pure ZnO rods.Comment: 8 Pages, 3 Figure

Determination of Copper, Total Chromium and Silver in Impregnated Carbon

Carbon samples were impregnated with ammonical solutions of silver salt alone and in combination with Cu and Cr salts. The impregnated samples were characterised for Cu, total Cr and Ag. Copper was extracted as CuCl/sub 2/ using concentrated HCl and Cr with NaOH. Silver was extracted from impregnated carbon using HNO3 and sodium thiosulphate (Na/sub 2/S/sub 2/O/sub 3/-5H/sub 2/0) and ashed impregnated carbons using aqua regia. The extracted metals in their solutions were quantitatively determined by titrimetric method and atomic absorption spectroscopy. The results were within acceptable limits of error. Sodium thiosulphate is recommended for extraction of Ag, as it accomplishes complete leaching of Ag faster than the other extracting agents

Kinetics and kinematics of diabetic foot in type 2 diabetes mellitus with and without peripheral neuropathy: a systematic review and meta-analysis.

Diabetes mellitus patients are at increased risk of developing diabetic foot with peripheral neuropathy, vascular and musculoskeletal complications. Problems develop with a relatively high risk of infection, gangrene and amputation. In addition, altered plantar pressure distribution is an important etiopathogenic risk factor for the development of foot ulcers. The purpose of this systematic review is to understand the biomechanical changes involved through studies of foot kinematic and kinetic in type 2 diabetes mellitus. Scientific articles were identified using electronic databases including Science Direct, CINAHL, Springer Link, Medline, Web of Science, and Pubmed. The selection of articles to include in the systematic review was narrorwed after reading the full text, focusing on studies that used experimental designs relating to the biomechanics of diabetic foot. The meta-analysis report on gait velocity (neuropathy = 128 and non-diabetes = 131) showed that there was a significantly lower gait velocity in neuropathy participants compared to non-diabetes age-matched participants at a high effect level (-0.09, 95% CI -0.13 to 0.05; p < 0.0001). Regarding knee-joint flexion range, there was a significant difference between neuropathy and non-diabetes groups (4.75, 95% CI, -7.53 to 1.97, p = 0.0008). The systematic review found significant differences in kinematic and kinetic variables among diabetic with neuropathy, diabetic without neuropathy and non-diabetic individuals. The review also found that the sample sizes used in some studies were not statistically significant enough contribute reliably to the meta-analysis, so further studies with higher sample sizes are required

Superconformal Multi-Black Hole Moduli Spaces in Four Dimensions

Quantum mechanics on the moduli space of N supersymmetric Reissner-Nordstrom black holes is shown to admit 4 supersymmetries using an unconventional supermultiplet which contains 3N bosons and 4N fermions. A near-horizon limit is found in which the quantum mechanics of widely separated black holes decouples from that of strongly-interacting, near-coincident black holes. This near-horizon theory is shown to have an enhanced D(2,1;0) superconformal symmetry. The bosonic symmetries are SL(2,R) conformal symmetry and SU(2)xSU(2) R-symmetry arising from spatial rotations and the R-symmetry of N=2 supergravity.Comment: 23 pages, harvmac. v2: many typos fixe

Comparative evaluation of the therapeutic efficacy of rumen buffers and direct fed microbials (DFM) in sub-acute ruminal acidosis in dairy cows

Sub-acute ruminal acidosis (SARA) in dairy cattle is a disorder of ruminal fermentation caused by the ingestion of large amounts of concentrates with inadequate amounts of fibre. The condition is characterized by sustained and marked decrease in rumen liquor pH ≤5.5 for at least three hours of each day. Rumen buffers and direct fed microbials (DFM) are dietary supplements that had been used in the management of SARA. Rumen liquor samples of dairy cows from the organized farms and households of Wayanad district which were at the risk of SARA were collected by rumenocentesis for rumen pH estimation. Blood samples were collected from cows positive for SARA and subjected to haemato-biochemical evaluations. Three different therapeutic protocols involving oral administration of sodium bicarbonate, Lithothamnium calcareum extracts as rumen buffers and a mixture Saccharomyces cerevisiae and Aspergillus oryzae as direct fed microbial were compared in SARA positive cows for 14 days and the efficacy of the treatment was evaluated by the improvement in rumen liquor pH after the treatment period. Rumen buffer like sodium bicarbonate was found to be more efficient than Lithothamnium calcareum and DFMs like Saccharomyces cerevisiae and Aspergillus oryzae mixture in improving the rumen pH values in cattle positive for SARA

Nanophotothermolysis of Poly-(vinyl) Alcohol Capped Silver Particles

Laser-induced thermal fusion and fragmentation of poly-(vinyl) alcohol (PVA)-capped silver nanoparticles in aqueous medium have been reported. PVA-capped silver nanoparticles with an average size of 15 nm were prepared by chemical reduction technique. The laser-induced photo-fragmentation of these particles has been monitored by UV-visible spectroscopy and transmission electron microscopy. The morphological changes induced by thermal and photochemical effects were found to influence the optical properties of these nanoparticles

Properties of high-frequency wave power halos around active regions: an analysis of multi-height data from HMI and AIA onboard SDO

We study properties of waves of frequencies above the photospheric acoustic cut-off of $\approx$5.3 mHz, around four active regions, through spatial maps of their power estimated using data from Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). The wavelength channels 1600 {\AA} and 1700 {\AA} from AIA are now known to capture clear oscillation signals due to helioseismic p modes as well as waves propagating up through to the chromosphere. Here we study in detail, in comparison with HMI Doppler data, properties of the power maps, especially the so called 'acoustic halos' seen around active regions, as a function of wave frequencies, inclination and strength of magnetic field (derived from the vector field observations by HMI) and observation height. We infer possible signatures of (magneto-)acoustic wave refraction from the observation height dependent changes, and hence due to changing magnetic strength and geometry, in the dependences of power maps on the photospheric magnetic quantities. We discuss the implications for theories of p mode absorption and mode conversions by the magnetic field.Comment: 22 pages, 12 figures, Accepted by journal Solar Physic

Super D-branes from BRST Symmetry

Recently a new formalism has been developed for the covariant quantization of superstrings. We study properties of Dp-branes and p-branes in this new framework, focusing on two different topics: effective actions and boundary states for Dp-branes. We present a derivation of the Wess-Zumino terms for super (D)p-branes using BRST symmetry. To achieve this we derive the BRST symmetry for superbranes, starting from the approach with/without pure spinors, and completely characterize the WZ terms as elements of the BRST cohomology. We also develope the boundary state description of Dp-branes by analyzing the boundary conditions for open strings in the completely covariant (i.e., without pure spinors) BRST formulation.Comment: 31 pp; journal version, expended discussion of D-brane pure spinor constraints in Section 2.

A Simple Shell Model for Quantum Dots in a Tilted Magnetic Field

A model for quantum dots is proposed, in which the motion of a few electrons in a three-dimensional harmonic oscillator potential under the influence of a homogeneous magnetic field of arbitrary direction is studied. The spectrum and the wave functions are obtained by solving the classical problem. The ground state of the Fermi-system is obtained by minimizing the total energy with regard to the confining frequencies. From this a dependence of the equilibrium shape of the quantum dot on the electron number, the magnetic field parameters and the slab thickness is found.Comment: 15 pages (Latex), 3 epsi figures, to appear in PhysRev B, 55 Nr. 20 (1997