Cooperativity in multiple unusual weak bonds

This review covers two aspects concerning cooperativity in multiple weak bonds: a summary of literature results and a theoretical study of a complete series of model complexes. All the 15 combination of five weak bonds were explored: hydrogen bonds, hydric bonds, dihydrogen bonds, halogen bonds and ion–π interactions. Since in several cases there were no examples reported, a systematic exploration has been carried out on simple models at the MP2/aug-cc-pVTZ level. The results thus obtained have been analyzed using the atoms in molecules methodology.     

Mixed micellization of anionic–nonionic surfactants in aqueous media: a physicochemical study with theoretical consideration

Mixed micellization of binary and ternary mixtures of anionic and nonionic surfactants, such as lithium dodecyl sulfate, polyoxyethylene(23)laurylether, and polyoxyethylene-tert-octylphenylether, is studied in aqueous solution using tensiometric, conductometric, and spectrophotometric methods. Although tensiometry and conductometry complement each other closely, the spectroscopic critical micellar concentration (cmc) is far from agreement with tensiometric study. Several parameters, e.g., cmc, degree of counterion binding, free energies of micellization, and interfacial adsorption, have been evaluated. Established theories of Clint, Rosen, Rubingh, Motomura, Georgiev, Maeda, and Blankschtein were applied to evaluate the mole fraction of different components in the self-aggregated phase, the interaction parameter, free energy contributions, and expected cmc.     

Theory of Weak Modified Electron Acoustic Double Layers and Solitary Waves in Presence of Negative Ions

We have studied the analytic solutions for modified electron acoustic double layers and solitary waves in a four component plasma system viz. two electrons and two ions, one positive and the other negative. It has been shown that DL solution does not exist when the temperatures of the free and the trapped particles are considered to be same for all the free species. On the other hand, DL solutions are found to exist when the effects of the reflected electrons (hot) are considered. The velocity and thickness of the DL have been valculated.     

MyD88-dependent and independent pathways of Toll-Like Receptors are engaged in biological activity of Triptolide in ligand-stimulated macrophages

Background  

Triptolide is a diterpene triepoxide from the Chinese medicinal plant Tripterygium wilfordii Hook F., with known anti-inflammatory, immunosuppressive and anti-cancer properties.     

Quantum dynamics of molecules in 4He nano-droplets: Microscopic superfluidity

High resolution spectroscopy of doped molecules in ⁴He nano-droplets and clusters gives a signature of superfluidity in microscopic system, termed as microscopic superfluidity. Ro-vibrational spectrum of ⁴He_N-M clusters is studied with the help of some important observations, revealed from experiments (viz., localised and orderly arrangement of ⁴He atoms, although, being free to move in the order of their locations; individual ⁴He atoms can not be tagged as normal/ superfluid, etc.) and other factors (e.g., consideration that the ⁴He atoms which happen to fall in the plane of rotation of a molecule, render a equipotential ring and thus, do not take part in rotation; etc.) which effect the rotational and vibrational spectrum of the system. This helps us in successfully explaining the experimental findings which state that the rotational spectrum of clusters have sharp peaks (indicating that the molecule rotates like a free rotor) and moment of inertia and vibrational frequency shift have a non-trivial dependence on N.     

Electroluminescence of colloidal ZnSe quantum dots

The article reports a green chemical synthesis of colloidal ZnSe quantum dots at a moderate temperature. The prepared colloid sample is characterised by UV-vis absorption spectroscopy and transmission electron microscopy. UV-vis spectroscopy reveals as-expected blue-shift with strong absorption edge at 400 nm and micrographs show a non-uniform size distribution of ZnSe quantum dots in the range 1-4 nm. Further, photoluminescence and electroluminescence spectroscopies are carried out to study optical emission. Each of the spectroscopies reveals two emission peaks, indicating band-to-band transition and defect related transition. From the luminescence studies, it can be inferred that the recombination of electrons and holes resulting from interband transition causes violet emission and the recombination of a photon generated hole with a charged state of Zn-vacancy gives blue emission. Meanwhile electroluminescence study suggests the application of ZnSe quantum dots as an efficient light emitting device with the advantage of colour tuning (violet-blue-violet).     

QCD phase transitions from relativistic hadron models

The models of translationally invariant infinite nuclear matter in the relativistic mean field models are very interesting and simple, since the nucleon can connect only to a constant vector and scalar meson field. Can one connect these to the complicated phase transitions of QCD? For an affirmative answer to this question, one must consider models where the coupling contstants to the scalar and vector fields depend on density in a nonlinear way, since as such the models are not explicitly chirally invariant. Once this is ensured, indeed one can derive a quark condensate indirectly from the energy density of nuclear matter which goes to zero at large density and temperature. The change to zero condensate indicates a smooth phase transition.     

Effect of harmonic confinement on correlation studies of a spin-polarized s-wave superconductor

We study different correlation functions for a spin imbalanced and harmonically trapped Fermi gas in two dimensions described by an attractive Hubbard model. Eigensolutions obtained via numerically solving Bogoliubov de Gennes equations are used to compute the local pairing amplitudes which show significantly different behaviour for the trapped case where the profile is radially modulated in contrast with a spatial modulation extending throughout the lattice geometry when trap effects are switched off. Further, different experimentally accessible quantities, such as pair–pair, density–density correlations and local density fluctuations show characteristic fluctuations for the spin polarized phase, which however wash away as the trapping effects are turned on. A contrasting scenario is presented corresponding to the case when the spin polarization effects are turned off.     

Electron-spin motion: a new tool to study ferromagnetic films and surfaces

When electrons are interacting with a ferromagnetic material, their spin-polarization vector is expected to move. This spin motion, comprising an azimuthal precession and a polar rotation about the magnetization direction of the ferromagnet, has been studied in spin-polarized electron scattering experiments both in transmission and reflection geometry. In this review we show that electron-spin motion can be considered as a new tool to study ferromagnetic films and surfaces and we discuss its application to a number of different problems: (a) the transmission of spin-polarized electrons across ferromagnetic films, (b) the influence of spin-dependent gaps in the electronic band structure on the spin motion in reflection geometry, (c) interference experiments with spin-polarized electrons and (d) the influence of lattice relaxations in ferromagnetic films on the spin motion.