R-Charged Black Hole and Neutrino Oscillation

In this paper we consider neutrino oscillation in general curved space-times. Then we calculate neutrino oscillation length in the R-charged black hole background, which is a five dimensional space-time, and compare it with the results of various backgrounds. We obtain effect of the electrical charge corresponding to the chemical potential on the oscillation length.     

Efficient synthesis,reactions, and biological activities of new thieno and furopyrazolo[3,4-b]pyrazines and their related heterocycles

In the present investigation, a simple and straightforward methodology for the preparation of novel bifunctional thienopyrazolopyrazines 4a–d has been reported. Synthesis of thieno or furopyrazolopyrazines 5a , b , e , f was achieved by the reaction of o-amino-esters 4a , b , e , f with 2,5-dimethoxytetrahydrofuran. The latter pyrrolyl derivatives 5a , b , e , f were used as starting intermediates for the synthesis of new pyrimido, pyrido, and pyrazino heterocycles fused to the thieno or furopyrazolopyrazine moiety. Furthermore, alkaline hydrolysis of the o-amino-ester 4a followed by acidification afforded the corresponding o-amino carboxylic acid 15 , which was used as a versatile precursor for the synthesis of other heterocyclic compounds fused to the thienopyrazolopyrazine ring system, namely: pyrimidine, oxazine, oxazepine, and pyridine derivatives 16–23 . The chemical structures of the synthesized compounds were confirmed on the basis of elemental and spectral analyses (Fourier-transform infrared spectroscopy [FT-IR], ¹H nuclear magnetic resonance [NMR], and mass spectroscopy [MS] in addition to ¹³C NMR for some of them). Moreover, from the biological screening, we found that most of the tested compounds exhibited promising antifungal, antibacterial, and anti-inflammatory activities compared with the corresponding reference drugs.     

Flotation-separation of aluminum from some water samples using powdered marble waste and oleic acid.

Bench-scale experiments were conducted in the laboratory, aiming to remove aluminum from water. They were based on the use of powdered marble wastes (PMW), which are inexpensive and produced in large quantity, and thus potentially cause environmental problems, as an effective inorganic sorbent and oleic acid (HOL) as surfactant. The main parameters (solution pHs, sorbent, surfactant and aluminum concentrations, shaking time, ionic strength and the presence of foreign ions) that influence the sorptive-flotation process were examined. Good results were obtained under the optimum conditions, for which nearly 100% of aluminum at pH 7 and at room temperature (approximately 25 degrees C) was removed. The procedure was successfully applied to the recovery of aluminum spiked to some natural water samples. Moreover, a sorption and flotation mechanism is suggested.     

BSA Interaction,Molecular Docking,and Antibacterial Activity of Zinc(II) Complexes Containing the Sterically Demanding Biomimetic N3S2 Ligand: The Effect of Structure Flexibility

Two zinc(II) complexes, DBZ and DBZH₄, that have (ZnN₃S₂) cores and differ in the bridging mode of the ligating backbone, effectively bind to BSA. The binding affinity varies as DBZ > DBZH₄ and depends on the ligand structure. At low concentrations, both complexes exhibit dynamic quenching, whereas at higher concentrations they exhibit mixed (static and dynamic) quenching. The energy transfer mechanism from the BSA singlet excited state to DBZ and DBZH₄, is highly likely according to steady-state fluorescence and time-correlated singlet photon counting. Molecular docking was used to support the mode of interaction of the complexes with BSA and showed that DBZ had more energy for binding. Furthermore, antibacterial testing revealed that both complexes were active but to a lesser extent than chloramphenicol. In comparison to DBZH₄, DBZ has higher antibacterial activity, which is consistent with the binding constants, molecular docking, and particle size of adducts. These findings may have an impact on biomedicine.     

Sorption-desorption of radiocesium on various sorbents in presence of humic acid

In general, the amount of radiocesium sorbed by the five sorbents with 0.01 mol·dm^–3 NaCl was in order zeolite > NiFeCN–SiO₂ > montmorillonite > aerogel > silica gel. Addition of humic acid solution to the sorbents depressed the sorption of cesium by all sorbents, except for NiFeCN–SiO₂ was not seen, with the greatest effect showing to the aerogel. The presence of humic acid resulted in an enhanced desorption of cesium from zeolite, NiFeCN–SiO₂ and to a lesser extent from montmorillonite and silica gel. The order of cesium retention following desorption for both sorbent and sorbent/humic-acid mixtures was zeolit > NiFeCN–SiO₂ > montmorillonite > silica gel. The presence of humic acid resulted in decreasing of distribution coefficient values for both sorption and desorption processes.     

Simulation of Rate Dependent Plasticity of Polymers

Polycarbonate is an amorphous polymer which exhibits nonlinear deformation before failure. It shows a pronounced strength-differential effect between compression and tension. Strain rate influences the mechanical response of the polycarbonate. In particular, the yield stress is increased with increasing strain rate. The concept of stress mode dependent weighting function is used in the proposed model to simulate the asymmetric effects for different loading speeds. In this concept, an additive decomposition of the flow rule is assumed into a sum of weighted stress mode related quantities. The characterization of the stress modes is obtained in the octahedral plane of the deviatoric stress space in terms of the mode angle, such that stress mode dependent scalar weighting functions can be constructed. The resulting evolution equations are updated using a backward Euler scheme and the algorithmic tangent operator is derived for the finite element equilibrium iteration. The numerical implementation of the resulting set of constitutive equations is used in a finite element program for parameter identification. The proposed model is verified by showing a good agreement with the experimental data. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)