Temperature and pressure variation of the recoilless fraction for119Sn:Pd Mössbauer system

The variation of the recoilless fraction ‘f’ as a function of temperature and pressure of¹¹⁹Sn embedded as a dilute impurity in palladium (Pd) host has been calculated after incorporating the changes in the force constant and mass at the impurity site using Debye model and phonon frequency spectrum (pfs). The comparison of the results have been made with the available experimental values.     

LC–UV Assay for Simultaneous Estimation of Aromatic Turmerone, α/β-Turmerone and Curlone: Major Bisabolane Sesquiterpenes of Turmeric Oil in Rabbit Plasma for Application to Pharmacokinetic Studies

The herbal medicament derived from the lipid soluble fraction obtained from Curcuma longa L. (Zingiberaceae) has shown potential neuroprotective activity in disorders like stroke. HM has been standardized with three biomarkers: ar-turmerone, α/β-turmerone and curlone, major bisabolane sesquiterpenes of turmeric oil. Development of a biaonalytical method for these sesquiterpenes was initiated to characterize its preclinical pharmacokinetics in rabbits to accelerate its development as a potential candidate for vascular complications. Since, the compounds are structurally and chemically very similar, gradient elution was utilized on a C-18 reversed phase column with a mobile phase comprising of acetonitrile and deionised water. The UV detector was set at wavelengths 240 and 270 nm. The sample clean-up was performed by protein precipitation with acetonitrile. The method was reasonably sensitive with limits of quantitation (LOQ) of 0.098 μg mL^?1 in plasma for all the analytes. Accuracy and precision were within the acceptable limits, as indicated by relative standard deviation (% RSD) varying from 1.3 to 13.6% and bias values ranging from ?5.5 to 10.3%, respectively. Moreover, the analytes were stable in plasma even after three freeze-thaw cycles. The method was applied to generate preliminary pharmacokinetics of turmeric oil in rabbits after intravenous administration.     

Inference on superimposed subcritical Galton-Watson processes with immigration

Summary In this paper we consider the superimposed processZ generated by two independent subcritical Galton-Watson processesX ₁ andX ₂, with immigration, by the relationZ=X ₁ +X ₂. The seemingly second order autoregressive relation, that is identified inZ, is exploted towards proposing CAN estimators for the parameters ofZ,X ₁ andX ₂, based on only a partial realisation ofZ, using time series techniques. The results of this paper are motivated by a time series approach for studying specific branching processes due to Venkataraman (1982,Adv. Appl. Prob.,14, 1–20).     

Synthesis and electrochemical studies of charge-transfer complexes of thiazolidine-2,4-dione with σ and π acceptors

In the present work, we report the synthesis and characterization of novel charge-transfer complexes of thiazolidine-2,4-dione (TZD) with sigma acceptor (iodine) and pi acceptors (chloranil, dichlorodicyanoquinone, picric acid and duraquinone). We also evaluated their thermal and electrochemical properties and we conclude that these complexes are frequency dependent. Charge-transfer complex between thiazolidine-2,4-dione and iodine give best conductivity. In conclusion, complex with sigma acceptors are more conducting than with pi acceptors.     

Kinetics of hydrogen abstraction reaction between trifluoromethyl formate and OH radical: A theoretical investigation

Kinetics and mechanism of the hydrogen abstraction reaction between trifluoromethyl formate, CF₃OCHO, and OH radical have been investigated by using ab initio molecular orbital theory up to G2(MP2) level. The hydrogen abstraction rate constant has been calculated for the first time over a temperature range of 250–450 K by using standard transition state theory including the tunneling correction. Arrhenius parameters of the reaction have been estimated from the temperature dependence of the calculated rate constant. The calculated value for the rate constant (2.0 × 10^?14 cm³ molecule^?1 s^?1) at 298 K is found to be in very good agreement with the recent experimental results. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 500–507, 2002     

Theorie der Peptisation und Schutzwirkung von Kolloiden und Nichtelektrolyten

Ohne Zusammenfassung Deutsch von Johannes Albrecht (Leipzig). Herrn Prof. N. R. Dhar bin ich zu bestem Dank verpflichtet.     

Ultra high vacuum electron spectrometer for ‘DSCEMS’

Depth Selective Conversion Electron Mössbauer Spectroscopy (DSCEMS) has become a very important surface science technique during the last one decade and attracted world wide interest specially because it gives more detailed knowledge of the properties and structure of the solid surfaces. The design and details of an ultra high vacuum cylindrical mirror analyser (CMA) for DSCEMS are described and illustrated.     

ChemInform Abstract: Study of Phase Transformation in BaTe2O6 by in situ High‐Pressure X‐Ray Diffraction,Raman Spectroscopy,and First‐Principles Calculations.

The title compound is synthesized by solid state reaction of a stoichiometric mixture of BaCO₃ and TeO₂ (air, 550 °C for 6 h, and 650 °C for 12 h).     

Analysis and Modeling of the Turbulent Diffusion of Turbulent Kinetic Energy in Natural Convection

Buoyant flows often contain regions with unstable and stable thermal stratification from which counter gradient turbulent fluxes are resulting, e.g. fluxes of heat or of any turbulence quantity. Basing on investigations in meteorology an improvement in the standard gradient-diffusion model for turbulent diffusion of turbulent kinetic energy is discussed. The two closure terms of the turbulent diffusion, the velocity-fluctuation triple correlation and the velocity-pressure fluctuation correlation, are investigated based on Direct Numerical Simulation (DNS) data for an internally heated fluid layer and for Rayleigh–Bénard convection. As a result it is decided to extend the standard gradient-diffusion model for the turbulent energy diffusion by modeling its closure terms separately. Coupling of two models leads to an extended RANS model for the turbulent energy diffusion. The involved closure term, the turbulent diffusion of heat flux, is studied based on its transport equation. This results in a buoyancy-extended version of the Daly and Harlow model. The models for all closure terms and for the turbulent energy diffusion are validated with the help of DNS data for internally heated fluid layers with Prandtl number Pr = 7 and for Rayleigh–Bénard convection with Pr = 0.71. It is found that the buoyancy-extended diffusion model which involves also a transport equation for the variance of the vertical velocity fluctuation gives improved turbulent energy diffusion data for the combined case with local stable and unstable stratification and that it allows for the required counter gradient energy flux.