Jai Singh

Genome-Wide Linkage Scan to Identify Loci Associated with Type 2 Diabetes and Blood Lipid Phenotypes in the Sikh Diabetes Study

In this investigation, we have carried out an autosomal genome-wide linkage analysis to map genes associated with type 2 diabetes (T2D) and five quantitative traits of blood lipids including total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, and triglycerides in a unique family-based cohort from the Sikh Diabetes Study (SDS). A total of 870 individuals (526 male/344 female) from 321 families were successfully genotyped using 398 polymorphic microsatellite markers with an average spacing of 9.26 cM on the autosomes. Results of non-parametric multipoint linkage analysis using Sall statistics (implemented in Merlin) did not reveal any chromosomal region to be significantly associated with T2D in this Sikh cohort. However, linkage analysis for lipid traits using QTL-ALL analysis revealed promising linkage signals with p≤0.005 for total cholesterol, LDL cholesterol, and HDL cholesterol at chromosomes 5p15, 9q21, 10p11, 10q21, and 22q13. The most significant signal (pu200a=u200a0.0011) occurred at 10q21.2 for HDL cholesterol. We also observed linkage signals for total cholesterol at 22q13.32 (pu200a=u200a0.0016) and 5p15.33 (pu200a=u200a0.0031) and for LDL cholesterol at 10p11.23 (pu200a=u200a0.0045). Interestingly, some of linkage regions identified in this Sikh population coincide with plausible candidate genes reported in recent genome-wide association and meta-analysis studies for lipid traits. Our study provides the first evidence of linkage for loci associated with quantitative lipid traits at four chromosomal regions in this Asian Indian population from Punjab. More detailed examination of these regions with more informative genotyping, sequencing, and functional studies should lead to rapid detection of novel targets of therapeutic importance.

Biosynthesis of silver nanoparticles using Carissa carandas berries and its potential antibacterial activities

AbstractMetal nanoparticles synthesis using the biological material offers a simple, biocompatible, cost-effective and nontoxic in character. A number of plant materials have been utilized as resource material for the most favorable biosynthesis of active nanomaterials. This study involves the synthesis of active silver nanoparticles (Ag NPs) using the Carissa carandas (Karonda) berry water extract at room temperature. The nanoparticles characterized at several parameters including shape, size, mass and charge with help of electron microscopy (TEM), Fourier transforms IR (FTIR), UV-VIS spectroscopy and Raman spectroscopy which proved the efficient silver nanoparticles to be useful in several practical applications. The UV-visible spectra showed the surface plasmon resonance peak at ~440u2009nm, which is weel recognized attribute peak in case of silver nanoparticles. Avarage size of the biogenic silver nanoparticles ranged from ~10–60u2009nm, predominantly spherical in shape. The suggested possible mechanisms for the synthesis of silver nanoparticles relies on reduction of AgNO3 due to occurrence of carinol (and related resonant compounds) in the berry extract with inductive effect of the proton of methoxy and allyl groups, present at ortho and para positions of the compounds. The biologically synthesized Ag NPs also showed efficient antibacterial activity against different pathogenic and non-pathogenic bacteria at par with the generic antibiotics.n HighlightsFirst report of efficient silver nanoparticles (Ag NPs) synthesis using the Karonda berry water extract.The size of the Ag NPs were found to be homogeneous in nature as evident from the TEM and FTIR analysis.The resultant Ag NPs showed enhanced antibacterial activity as compared to the Karonda berry water extract.

Structural and magnetic study of undoped and cobalt doped TiO2 nanoparticles

The present study investigates the influence of cobalt doping on the structural and magnetic properties of TiO2 nanoparticles prepared by a simple wet chemical method. The single phase anatase structure of Co-doped TiO2 nanoparticles was confirmed by X-ray powder diffraction. A morphological study using scanning electron microscopy and transmission electron microscopy indicates the formation of TiO2 nanoparticles of sizes 6–10 nm. The high resolution TEM image shows clear lattice fringes indicating the highly crystalline nature of the nanoparticles which was further analysed by selected area electron diffraction pattern which indicates a polycrystalline nature of anatase TiO2. The shifting and broadening of the most intense Eg (1) mode in micro-Raman study of Co-doped TiO2 nanoparticles and XPS spectra indicate the incorporation of Co in TiO2. Magnetic measurement shows ferromagnetic behavior at room temperature in undoped TiO2 which has originated due to the presence of oxygen vacancies which are intrinsic in nature. But the M–H curve of Co-doped TiO2 shows the coexistence of ferromagnetic and paramagnetic phases with enhanced magnetization. The enhancement in magnetization has arisen due to Co doping and the paramagnetism may be due to the presence of some undetected clusters of oxides of cobalt.

Study of structural, optical and magnetic properties of cobalt doped ZnO nanorods

Cobalt doped zinc oxide nanoparticles (NPs) and nanorods (NRs) were synthesized by a simple chemical method. An increase in the formation of nanorods with an increase in cobalt doping is found to occur from scanning electron microscopy and transmission electron microscopy studies. Powder X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction confirm the formation of a wurtzite crystal structure of ZnO. Shifting and broadening of the bands at 437xa0cm−1 and 579 cm−1 in the micro-Raman study of Co-doped ZnO nanostructures indicates the incorporation of Co in ZnO. Shifting of the absorption edge to lower wavelength and blue shift of the band gap is observed in UV-visible spectra of Co-doped ZnO samples. Field-dependent magnetization measurements exhibit diamagnetic behavior down to 2 K in the case of ZnO whereas Co-doped ZnO samples show coexistence of superparamagnetic and ferromagnetic behavior at room temperature and at 2 K. The observed ferromagnetism may have originated due to the exchange interaction between the localized d electrons in Co2+ atoms and free carriers generated due to Co-doping as well as due to cobalt clustering in the Co-doped samples.

Effect of precursors ratio on crystallinity and thermal stability of CH3NH3PbI3

CH3NH3PbI3 is a newly developed organic inorganic perovskite light harvesting (OIPLH) material which is using for different electronic applications. In this work, we have synthesized CH3NH3PbI3 with different ratio of precursor CH3NH3I and PbI2. We have tried to explain how the ratio of precursors affected the crystallinity and thermal stability of OIPLH material. XRD study of material shows that, crystallinity of material losses on increasing the precursor ratio and simultaneous thermal analysis (TGA/DTA) indicates the more thermal decomposition with increasing precursor ratio due to excess amount of CH3NH3I.

Structural and thermodynamic aspects of organic-inorganic mixed halide (CH3NH3PbI3-xBrx) perovskite

Mixed Bromine and iodine lead halide perovskite CH3NH3PbI3-xBrx have been synthesized by solution phase method using CH3NH3I and PbBr2 precursors in ambient conditions. X-ray diffraction indicates the formation of cubic perovskite at room temperature with space group of Pm3m. The mixed perovskite improved crystallanity and grain contour which may significant improve photovoltaic performance of perovskite devices. Thermodynamic behavior of such type of material also indicates energy absorption nature of materials.Mixed Bromine and iodine lead halide perovskite CH3NH3PbI3-xBrx have been synthesized by solution phase method using CH3NH3I and PbBr2 precursors in ambient conditions. X-ray diffraction indicates the formation of cubic perovskite at room temperature with space group of Pm3m. The mixed perovskite improved crystallanity and grain contour which may significant improve photovoltaic performance of perovskite devices. Thermodynamic behavior of such type of material also indicates energy absorption nature of materials.

Study of morphological changes in scattering and optically anisotropic medium through correlation images

Correlation images are very useful in determining the morphological changes. We have investigated the correlation image analysis on depolarization and retardance matrices of polystyrene and gelatine samples respectively. We observed that that correlation images have a potential to show a significant variation with change in the concentration of samples (polystyrene and gelatine). For polystyrene microspheres the correlation value decreases with increasing scattering coefficient. In gelatine samples the correlation also decreases with sample concentration. This variation in correlation for retardance shows the change in a birefringence property of gelatine solution.Correlation images are very useful in determining the morphological changes. We have investigated the correlation image analysis on depolarization and retardance matrices of polystyrene and gelatine samples respectively. We observed that that correlation images have a potential to show a significant variation with change in the concentration of samples (polystyrene and gelatine). For polystyrene microspheres the correlation value decreases with increasing scattering coefficient. In gelatine samples the correlation also decreases with sample concentration. This variation in correlation for retardance shows the change in a birefringence property of gelatine solution.

Color tunable emission through energy transfer from Yb3+ co-doped SrSnO3: Ho3+ perovskite nano-phosphor

First time color tunable lighting observed from Ho3+ and Yb3+ co-doped SrSnO3 perovskite. Down-conversion and up-conversion (UC) photoluminescence emission spectra were recorded to understand the whole mechanism of energy migration between Ho3+ and Yb3+ ions. The intensity of green and red emission varies with Yb3+ doping which causes multicolour emissions from nano-phosphor. The intensity of UC red emission (654xa0nm) obtained from 1xa0at.% Ho3+ and 3xa0at.% Yb3+ co-doped nano-phosphor is nine times higher than from 1xa0at.% Ho3+ doped SrSnO3 nano-phosphor. Enhanced brightness of 654xa0nm in UC process belongs in biological transparency window so that it might be a promising phosphor in the bio-medical field. Moreover, for the other Yb3+ co-doped nano-phosphor, Commission Internationale de l’Éclairage chromaticity co-ordinates were found near the white region and their CCT values lie in the range 4900–5100xa0K indicating cool white. Decay time was measured for 545xa0nm emission of Ho3+ ion found in 7.652 and 8.734xa0µs at 355xa0nm excitation. The variation in lifetime was observed in ascending order with increasing Yb3+ concentration which supports PL emission spectra observation that with increasing Yb3+ concentration, rate of transition has changed. These studies reveal that Ho3+ and Yb3+ co-doped phosphor is useful for fabrication of white LEDs.

Role of organic and inorganic cations on thermal behavior of lead iodide perovskites

Recently, organic-inorganic perovskite materials have attracted much attention due to their enormous potential for use in future of new sustainable energy sources. However, fabrication of environmental friendly perovskite and achieving better stability is a major concern towards the commercialization. Here we study the role of cations in the perovskite powder and their influence upon thermodynamic stability. In this study we find, inorganic (cesium, Cs+) cation is shown to be more efficient in the thermal stabilization of the perovskite material than organic (methylamine, CH3NH2+) cation. This study reviles that stability of perovskite can be improved by incorporation of inorganic cation.