Universal multiplicity hypothesis of QCD: Bounds on quark gluon coupling,quark mass and confinement region

Assuming the validity of the universal multiplicity hypothesis of quantum chromodynamics, we estimate bounds on quark gluon coupling (α_S) and quark mass (m) from the experimental data on charged hadron multiplicities. We obtain 0.3 < α_S < 0.5 and m ≈ 100 MeV. Our analysis also suggests the universal quark confinement region to be ≈ O (m_π^?1). Comparison with experiment is made for both the hadronic and leptonic induced reactions.     

Effect of orientation,anisotropy, and water on the relaxation behavior of nylon 6 from 4.2 to 300°K

The relaxation behavior of nylon 6 from 4.2 to 300°K was investigated as a function of orientation, anisotropy and moisture content by using an inverted free-oscillating torsion pendulum. Three new relaxations, δ at 53°K, ? below 4.2°K, and ζ at 20°K, were discovered. The characteristics of these new relaxations strongly depend on the orientation anisotropy, and concentration of adsorbed water in the specimens. The results suggest that the mechanism of the γ process is associated with the motions of both the polar and methylene units. The mechanism of the β relaxation is postulated to originate with motions of both non-hydrogen-bonded polar groups and polymer—water complex units. The behavior of the α peak is consistent with the hypothesis that it originates with the rupture of interchain hydrogen bonding due to the motions of long-chain segments in the amorphous regions. Finally, the data strongly support the proposition that two types of water, tightly bound and loosely bound, exist in nylon 6.     

Hydroxy(tosyloxy)iodo]benzene mediated alpha-azidation of ketones

Reaction of various ketones with [hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment of the alpha-tosyloxy ketones thus generated in situ with NaN3 offers a one-pot procedure for the synthesis of alpha-azido ketones. The HTIB used in this conversion may also be generated in situ by using iodosobenzene in combination with p-toluene-sulphonic acid.     

Comparative study of p‐amino benzhydrazide and m‐amino benzhydrazide by free radicals and free electron transfer

The bimolecular electron transfer from p‐amino benzhydrazide (PABH) and its meta‐derivative (m‐amino benzhydrazide (MABH)) to specific one‐electron oxidant results in the formation of anilino radical. In case of PABH, reaction with ^?OH radicals results in the synchronous formation of adduct as well as anilino radical. The interesting observation is that the yield of the anilino radical increases with increase in pH. The effect of substitution also has a significant effect on the formation of adduct. In case of MABH, significant yield of anilino radical gets form on reaction with ^?OH radical. The free radical electron transfer from PABH and MABH to parent radical cation of non‐polar solvent also results in the formation of anilino radical only suggesting that the radical cation of PABH and MABH has short life time. The above results were supported by quantum chemical calculations. Copyright © 2013 John Wiley & Sons, Ltd.     

Exact solution of the Schrödinger equation for a particle in a regular N-simplex

We present the exact solution for the Schrödinger equation for a particle inside an N-dimensional regular simplex shaped enclosure. This result extends and unifies the earlier results for equilateral triangle and K-tetrahedron billiards.     

Discrete π Stack of a Tweezer-Shaped Naphthalenediimide–Anthracene Conjugate

The design and synthesis of a tweezer-shaped naphthalenediimide (NDI)–anthracene conjugate ( 2NDI ) are reported. In the structure of the closed form (π_NDI ⋅⋅⋅ π_NDI stack) of 2NDI , which was elucidated by single-crystal XRD, the existence of C−H ⋅⋅⋅ O hydrogen bonding involving the nearest carbonyl oxygen atom of an NDI unit was suggested. The tunability of π_NDI ⋅⋅⋅ π_NDI interactions was studied by means of UV/Vis absorption, fluorescence and NMR spectroscopy and molecular modelling. This revealed that the π_NDI ⋅⋅⋅ π_NDI interactions in 2NDI affect the absorption and emission properties depending on the temperature. Furthermore, in polar solvents, 2NDI prefers the stronger π_NDI ⋅⋅⋅ π_NDI stack, whereas the π_NDI ⋅⋅⋅ π_NDI interaction is diminished in nonpolar solvents. Importantly, the conformational variations of 2NDI can be reversibly switched by variation in temperature, and this suggests potential application for fluorogenic molecular switches upon temperature changes.     

Methods and approaches for determination and enantioseparation of (RS)‐propranolol

Propranolol, a β‐adrenergic receptor antagonist, is a chiral compound that is marketed as a racemate, but only the (S)‐(?)‐enantiomer is responsible for the β‐adrenoceptor blocking activity. Different chromatographic methods have been applied for separation and determination of enantiomers of (RS)‐propranolol. In this article a review is presented on different liquid chromatographic methods used for enantioseparation of (RS)‐propranolol, using both HPLC and TLC. In addition, some aspects of enantioseparation under achiral phases of liquid chromatography have been briefly mentioned.     

CPMD/GULP QM/MM interface for modeling periodic solids: Implementation and its application in the study of Y‐zeolite supported Rhn clusters

We report here the development of hybrid quantum mechanics/molecular mechanics (QM/MM) interface between the plane‐wave density functional theory based CPMD code and the empirical force‐field based GULP code for modeling periodic solids and surfaces. The hybrid QM/MM interface is based on the electrostatic coupling between QM and MM regions. The interface is designed for carrying out full relaxation of all the QM and MM atoms during geometry optimizations and molecular dynamics simulations, including the boundary atoms. Both Born–Oppenheimer and Car–Parrinello molecular dynamics schemes are enabled for the QM part during the QM/MM calculations. This interface has the advantage of parallelization of both the programs such that the QM and MM force evaluations can be carried out in parallel to model large systems. The interface program is first validated for total energy conservation and parallel scaling performance is benchmarked. Oxygen vacancy in α‐cristobalite is then studied in detail and the results are compared with a fully QM calculation and experimental data. Subsequently, we use our implementation to investigate the structure of rhodium cluster (Rh_n; n = 2 to 6) formed from Rh(C₂H₄)₂ complex adsorbed within a cavity of Y‐zeolite in a reducible atmosphere of H₂ gas. © 2016 Wiley Periodicals, Inc.