Modulation of Intramolecular Charge Transfer Emission Inside Micelles: A Fluorescence Probe for Studying Microenvironment of Micellar Assemblies

Modulation of intramolecular charge transfer reaction of ethyl ester of N,N-Dimethylaminonaphthyl-(acrylic)-acid (EDMANA) in anionic sodium dodecyl sulfate (SDS), cationic cetyltrimethylammonium bromide (CTAB) and non-ionic p-tert-octylphenoxy polyoxyethanol (Triton-X 100, TX-100) micelles has been addressed using steady state and time resolved spectroscopy. The interaction of the CT probe EDMANA with micelles and its location inside the micelles have been investigated by the study of fluorescence spectral band position of EDMANA in micelle, the effective polarity of micelle-water interface and cetyl pyridinium chloride induced fluorescence quenching measurement. The effects of urea on the properties of the micelles such as Critical Micelle Concentration and the interaction between EDMANA and micelles have been explored using EDMANA as emission probe.     

Minimal length in quantum mechanics and non-Hermitian Hamiltonian systems

Deformations of the canonical commutation relations lead to non-Hermitian momentum and position operators and therefore almost inevitably to non-Hermitian Hamiltonians. We demonstrate that such type of deformed quantum mechanical systems may be treated in a similar framework as quasi/pseudo and/or -symmetric systems, which have recently attracted much attention. For a newly proposed deformation of exponential type we compute the minimal uncertainty and minimal length, which are essential in almost all approaches to quantum gravity.     

Solidified floating organic drop microextraction combined with high performance liquid chromatography for the determination of carbamazepine in human plasma and urine samples

Solidified floating organic drop microextraction (SFODME) in combination with high performance liquid chromatography was used for separation/preconcentration and determination of carbamazepine (CBZ) in human plasma and urine samples. Parameters that affect the extraction efficiency such as the type and volume of extraction solvent, ionic strength, sodium hydroxide concentration, stirring rate, sample volume and extraction time, were investigated and optimized. Under the optimum conditions (extraction solvent, 40 μL of 1-undecanol; sodium hydroxide concentration, 1 mol/L; temperature, 50 ℃; stirring speed, 400 r/min; sample volume, 8 mL; sodium chloride concentration, 3% (w/v) and extraction time, 60 min) the calibration curve was found to be linear in the mass concentration range of 0.4-700.0 μg/L. The limit of detection (LOD) was 0.1 μg/L and the relative standard deviation (RSD) for six replicate extraction and determination of carbamazepine at 100 μg/L level was found to be 4.1%. The method was successfully applied to the determination of CBZ in human plasma and urine samples.     

Bianchi Type-I Model with Cosmic String in the Presence of a Magnetic Field: Spinor Description

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmic string is investigated. A nonlinear spinor field is used to simulate the cosmological cloud of strings. It is shown that the spinor field simulation offer the possibility to solve the system of Einstein’s equation without any additional assumptions. It is pointed out that the present model is nonsingular at the end of the evolution and does not allow the anisotropic Universe to turn into an isotropic one.     

Smart photoactive soft materials for environmental cleaning and energy production through incorporation of nanophotocatalyst on polymers and textiles

Energy and environment are key issues for the sustainable development of human beings and are also the current and long‐term focuses of scientific research. New energy and environmental technologies in combination with polymer and textile science work to create many additional functions for conventional polymers and fabrics. Therefore, some novel technical polymers and textiles, such as photovoltaic and photocatalytic polymers and textiles, have begun to emerge. Generally, light‐activated chemicals, materials, or processes that are produced or enabled by light and the agent absorbing light starting a photochemical alteration in the system is nominated as photocatalyst. This review firstly introduces the different photoactive materials, their classifications, and degradation mechanism. Then, inorganic semiconductor nanoparticles were selected as the best candidate for the application in soft materials. Finally, a detailed study was provided on both preparations of photoactive soft materials using metal oxide semiconductors and their advantages and applications. This paper will be more helpful for the scientists working in the field of photoactive soft materials.     

Polaron assisted charge transfer in model biological systems

We use a tight binding Hamiltonian to simulate the electron transfer from an initialcharge-separating exciton to a final target state through a two-arm transfer model. Thestructure is copied from the model frequently used to describe electron harvesting inphotosynthesis (photosystems I). We use this network to provide proof of principle fordynamics, in quantum system/bath networks, especially those involving interferencepathways, and use these results to make predictions on artificially realizable systems.Each site is coupled to the phonon bath via several electron-phonon couplings. The assumedlarge energy gaps and weak tunneling integrals linking the last 3 sites give rise to“StarkWannier like” quantum localization; electron transfer to the target cluster becomesimpossible without bath coupling. As a result of the electron-phonon coupling, localelectronic energies relax when the site is occupied, and transient polaronic states areformed as photo-generated electrons traverse the system. For a symmetric constructivelyinterfering two pathway network, the population is shared equally between two sets ofequivalent sites and therefore the polaron energy shift is smaller. The smaller energyshift however makes the tunnel transfer to the last site slower or blocks it altogether.Slight disorder (or thermal noise) can break the symmetry, permitting essentially a “onepath”, and correspondingly more efficient transfer.     

Complex turbulent compressible flow computation using a two-layer approach

A two-layer approach is proposed to compute complex flows including separations. For high- and low-Reynolds-number regions we use a two-equation k-? model and a one-equation k-L model respectively. A robust algorithm is proposed for the treatment of the convective part of the turbulence equations. Several complex configurations including separations are computed.     

Dynamics of an Optically Switched Bistable Semiconductor Laser

The switching time of an optically switched laser diode between a locked mode and free oscillation mode is studied. By starting with linear stability analysis, analytical expressions are developed to predict the switching time. It is shown that the switching of optical output between the locked and unlocked modes is governed by two relaxation processes with different time constants, and the change in the first relaxation process, dependent on the carrier density in the initial state, gives a strong effect on the total switching time, in contrast to the dynamic behavior of the carrier density dominated by a single relaxation process. Our analytical results show that larger detuning and power of optical input are effective in shortening the switching time and are believed useful to estimate the switching time of an optically switched bistable laser diode.     

A model for the reaction mechanism of the transglutaminase 3 enzyme

Transglutaminase enzymes (TGases) catalyze the calcium dependent formation of an isopeptide bond between protein-bound glutamine and lysine substrates. Previously we have shown that activated TGase 3 acquires two additional calcium ions at site two and three. The calcium ion at site three results in the opening of a channel. At this site, the channel opening and closing could modulate, depending on which metal is bound. Here we propose that the front of the channel could be used by the two substrates for enzyme reaction. We propose that the glutamine substrate is directed from Trp236 into the enzyme, shown by molecular docking. Then a lysine substrate approaches the opened active site to engage Trp327, leading to formation of the isopeptide bond. Further, direct comparisons of the structures of TGase 3 with other TGases have allowed us to identify several residues that might potentially be involved in generic and specific recognition of the glutamine and lysine substrates.     

Viscosities of Some Tetraalkylammonium and Alkali-Metal Salts in N,N-Dimethylacetamide at 25°C

The viscosities of solutions of tetrapropylammonium bromide (Pr₄NBr), tetrabutylammonium bromide (Bu₄NBr), tetrapentylammonium bromide (Pen₄NBr), tetrahexylammonium bromide (Hex₄NBr), tetraheptylammonium bromide (Hep₄NBr), tetraoctylammonium bromide (Oct₄NBr), tetrabutylammonium tetraphenylborate (Bu₄NBPh₄), sodium tetraphenylborate (NaBPh₄), and potassium tetraphenylborate (KBPh₄) in N,N-dimethylacetamide are reported at 25^°C. The viscosity data havebeen analyzed by the Jones-Dole equation for associated electrolytes to evaluate the viscosity B coefficients of the electrolytes. These data have also been analyzed by the transition-state theory to obtain the contribution of the solutes to the free energy of activation for viscous flow of the solution. The ionic contribution to the viscosity B coefficient and the free energy of activation for viscous flow have been estimated using of the reference electrolyte Bu₄NBPh₄. The bromide, tetraphenylborate, and tetraalkylammonium ions are found to be weakly solvated in N,N-dimethylacetamide, whereas significant solvation has been detected for sodium and potassium ions. The viscosity of the solvent is greatly modified by the presence of all the ions investigated here with the exception of the bromide ion.