Imidazole derivatives as the organic precursor of ZnO nano particle

N₁-Hydroxy-2,4,5-trisubstituted imidazoles were synthesized starting from 1,2-diketones. The crystal structure of 4,5-dimethyl-2-(3-nitrophenyl)-1H-imidazol-1-ol has been determined. An unusual intermolecular hydrogen bonding through the association of water molecule has been reported. These imidazole derivatives can be thought of as the organic precursor for the synthesis of zinc oxide nano particles.     

The link between neutrino masses and proton decay in supersymmetric unification

Following recent joint works with K. Babu and F. Wilczek, I stress here that supersymmetric unification, based on symmetries like SO(10) or a string-derived G(224)=SU(2) _L ×SU(2) _R ×SU(4) ^C possesses some crucial features that are intimately linked to each other. They are (a) gauge-coupling unification; (b) the masses and mixings of all fermions, including especially the neutrinos; and last but not least (c) proton decay. In this context, it is noted that the value of $m_{v_L^\tau } \sim 1/20{\text{ }}eV$ , suggested by the Super-Kamiokande result, goes extremely well with the unification-hypothesis, based on the ideas of (i) SU(4)-color, (ii) left-right symmetry, and (iii) supersymmetry. A concrete proposal is presented within an economical SO(10)-framework that makes five successful predictions for the masses and mixings of the quarks and the charged leptons. The same framework explains why the ν_π?ν_τ oscillation angle is so large $(\sin ^2 2\theta _{\nu _\mu \nu _\tau }^{osc} \approx 0.82 - 0.96)$ and yet V _bc is so small (≈0.04), both in accord with observation. The influence of the masses of the neutrinos and of the charged fermions on proton decay is discussed concretely, within this framework. The $\bar \nu K^ + $ mode is expected to be dominant for SUSY SO(10) as well as SU(5). A distinctive feature of the SO(10) model, however, is the likely prominence of the μ⁺ K ⁰ mode, which, for SU(5), is highly suppressed. Our study shows that while current limits on the rate of proton decaying into $\bar \nu K^ + $ are compatible with theoretical expectations, improvements in these limits by a factor of 5–10 should either turn up events, or else the SO(10)-framework described here, which is otherwise so successful, will be in jeopardy. Prominence of theμ⁺ K ⁰ mode, if observed, will be most significant in that it will reveal the intriguing link that exists between neutrino masses and proton decay in the context of supersymmetric unification.     

New solutions for charged spheres in general relativity

Exact solutions of the Einstein-Maxwell field equations are obtained for the case of static and spherically symmetric distribution of charged matter. The solutions are obtained through the extension of a method originally used for neutral configurations and are conveniently matched to the Reissner-Nordstrom exterior metric. The physical plausability of the solutions is discussed and it is shown that some of them reduce in appropriate limits to known neutral or charged solutions.     

Effect of seasonal variation on dust samples of a winter fog affected urban environment of India,South East Asia

Physical and chemical characteristics of leaf dust (LD) samples, collected between 2011 and 2013, of a severely winter fog affected and polluted urban environment (Allahabad, India) of Indo-Gangetic plain are presented in this study. The weather changes in the study area are grouped into three effective annual seasonal periods – winter fog, pre-monsoon and post-monsoon. The pronounced impact of seasonal variations is observed in LD characteristics, as ~46% of the winter fog period samples ranges in size between 2.5 and 20 µm with high magnetic susceptibility (up to 938.22 × 10^?8 m³ kg^?1). In comparison, 35% of the LD from pre-monsoon period occurs in the size range of 100–300 µm with low magnetic susceptibility (up to 43.29 × 10^?8 m³ kg^?1). The fractal analysis involving submicroscopic clast dimension of LD also reveals a seasonal influence. The toxic metals (Pb, Zn, Cd, Cr and Ni) in LD belonging to winter fog and post-monsoon periods increase in comparison to samples from pre-monsoon time. Multivariate statistical analysis of trace element data suggests that the LD collected from winter fog and post-monsoon periods originate predominantly from anthropogenic source, whereas those collected during pre-monsoon owe their origin to crustal and anthropogenic sources, mainly. The present study has demonstrated the role of seasonal variation in controlling the physical and chemical properties of particulate matter based on multiple parameter analyses, and the derivation of the dust load from a mixed source (upper continental crust, anthropogenic and vehicular) for the study area for the first time.     

Exchange interaction at the interface of Fe-NiOnanocomposites

Fe-NiO nanocomposites with Fe to NiO ratio 20:80, 30:70 and 50:50 were prepared by a chemical route. X-ray diffraction and TEM measurements showed the presence of α-Fe and NiO phases in the prepared nanocomposites having an average crystallite size 17 nm. HRTEM image showed a structurally disordered phase at the Fe-NiO interface. Mössbauer spectra of the nanocomposites consist of a doublet along with a sextet corresponding to relaxed and blocked α-Fe phases, respectively. The dc magnetization measurements in field-cooled condition show a shift of hysteresis loop and an enhancement of coercive field at low temperature confirming the presence of exchange bias at Fe-NiO interfaces. The irreversibility observed in the FC and ZFC magnetization measurements also points to exchange bias effect.     

Synthesis of spiroheterocycles derived from benzo[f]chromanone

The syntheses of an important class of hitherto unreported spiro derivatives containing benzo[f]chromanone moiety involving very simple cyclocondensation reactions are described. Installation of pharmacologically active moieties like thiazolidine and thiazolidinone is achieved by taking simple reagents like ethylchloroacetate, 1, 2‐dibromo ethane and thioglycollic acid. J. Heterocyclic Chem., (2011).     

Synthesis of 3-Aryl-5-C-Glycosylisoxazoles from Several Aldehydo-Sugar Derivatives

ABSTRACT

The synthesis of several 3-aryl-5-glycosylisoxazole derivatives has been achieved. By condensation of the protected aldehydo-sugars 2,3-O-isopropylidene-D-glyceraldehyde (1), 2,3:4,5-di-O-isopropylidene-aldehydo-D-arabinose (2) and D-xylose (3), and 2,5-anhydro-3,4,5-tri-O-benzoyl-D-mannose (4) with benzoylmethylenetriphenylphosphorane, enulose derivatives were formed, which were later converted into a,ß-unsaturated ketoximes. These ketoximes were oxidatively cyclized with iodine and, after removal of the hydroxyl protecting groups, 3-phenyl-5-glycosylisoxazoles were formed.     

On Vertex Connectivity and Absolute Algebraic Connectivity for Graphs

Let G be a graph on n vertices with vertex connectivity v with 1 ≤ v ≤ n -2. We produce an attainable upper bound on the absolute algebraic connectivity of G in terms of n and v .