Physicochemistry of mixed micellization: Binary and ternary mixtures of cationic surfactants in aqueous medium

The importance of studying mixed micellization lies in tuning the performance of an amphiphile to bend through variation of stoichiometry of the blend. In this study, the binary and ternary mixed systems of cetylpyridinium chloride (CPC), tetradecyltrimethylammonium bromide, and dodecylpyridinium chloride (DPC) have been studied at 30°C using tensiometry and conductometry. In most cases, the cmc observed from either method is in close proximity whereas in CPC/DPC mixtures, tensometric cmc precedes conductometric cmc which may arise from a lowering in degree of counterion binding on micellar interface in the mixed system with lower stoichiometric mole fraction of CPC. Various existing theories have been used and the results were compared with the experimental observations.     

A novel route for in-situ H2O2 generation from selective reduction of O2 by hydrazine using heterogeneous Pd catalyst in an aqueous medium

Hydrogen peroxide in high yields can be generated with high efficiency at mild conditions (25 degrees C and atmospheric pressure) with the formation of only environment-friendly by-products (N2 and H2O) by a reduction of O2 by hydrazine from its hydrate/salt with its complete conversion in a short reaction period (相似文献   

MREI‐model calculations of Raman‐active modes in layered mixed crystals TiS2−xSex(0≤x≤2)

A modified random‐element isodisplacement model has been developed and used to calculate the concentration dependence of the wavenumbers of Raman‐active modes in mixed crystal system, TiS_2−xSe_x(0≤x≤2). Earlier theoretical work, based on the Jaswal model, predicted a phase transition in this system on cooling up to 125 K temperature for the composition x ≥ 1.2. But recently reported resistivity measurements did not find the existence of any phase transition for a composition x < 1.4 on cooling. Our calculations show these findings and give remarkably better fitting to Raman data. The estimated values of the force constants are found to lie generally in the range 10⁵–10⁶ amu cm⁻². Copyright © 2007 John Wiley & Sons, Ltd.     

Structure imaging and vanadium substitution in cubic TiCr2 Laves phase

Properties of Laves phase compounds can be tailored by alloying and microstructural engineering. V-substituted cubic TiCr₂ Laves phase has been studied to understand the location of V atoms in the lattice, by structural imaging and first-principle computations. Even though Ti, V and Cr appear next to each other in the periodic table, V preferentially replaces the Ti lattice producing anti-site defects. The defect formation energy for V substitution in Ti and in Cr lattice is 0.29 and 0.40 eV, respectively. V replacement in the Ti lattice generates atomic scale strain. Atomic numbers of V, Ti and Cr being very close, this phase is not quite suitable for incoherent imaging for understanding the structure and the chemistry. Instead, difference in channelling behaviour of electron waves along the Ti columns and along the Cr columns could be exploited to preferentially image the individual atom columns. Nature of the exit phase wave, phase and amplitude has been used to understand the contrast qualitatively. The intensity distribution of any particular atom column that is disturbed by the presence of foreign atom has been used to detect the position of V atoms. This method could be extended to study other Laves phases and complex intermetallic structures to understand their structure, defects and interfaces.     

Characterizations based on length-biased weighted measure of inaccuracy for truncated random variables

In survival studies and life testing, the data are generally truncated. Recently, authors have studied a weighted version of Kerridge inaccuracy measure for truncated distributions. In the present paper we consider weighted residual and weighted past inaccuracy measure and study various aspects of their bounds. Characterizations of several important continuous distributions are provided based on weighted residual (past) inaccuracy measure.     

Adsorption of Chromium on Composite Microspheres of Chitosan and Nano Iron Oxide

The batch removal of Cr(VI) ions from aqueous solution using binary composite microspheres of chitosan and nanoparticles of iron oxide under different conditions has been investigated in this study. The influences of initial chromium concentration, contact time, pH, temperature, and solid-liquid ratio have been reported. The adsorption data was fitted well in the Langmuir and Freundlich models and various static parameters were calculated. The mechanism of adsorption was studied by Fourier Transform Infrared spectroscopy (FTIR).     

Spectroscopic assessment of biomolecular changes in Helicobacter pylori and Epstein–Barr virus co-infected gastric epithelial cells

Helicobacter pylori and Epstein–Barr Virus (EBV) are Group 1 carcinogens that can enhance gastric cancer progression. Bioactive substances extracted from plants can be effective therapeutic agents in cancer treatment. For example, Withania somnifera extract-WSE reduces the Gankyrin oncoprotein, which is upregulated in the presence of H. pylori and EBV. The various biochemical and metabolic changes upon 24 hrs post-infection followed by W. somnifera extract (WSE) treatment on gastric epithelial cells (AGS) can be studied using spectroscopic techniques. In the biomedical sciences, Raman and NMR spectroscopy have been extensively employed to interpret cellular alterations contributing to the onset of infection and the severity of gastric cancer. More specifically, alterations in cellular biochemical homeostasis are linked to the moieties of cholesterol, collagen, choline, carbohydrate, lipids, tyrosine, and phenylalanine. Further, we have found significantly elevated FWHM for carbohydrates, tumor associated protein, collagen, cholesterol, and cholesterol ester in the co-infection model. We also looked into the potential correlation between these molecules using molecular network analysis and found several related factors that can be modulated through biomolecular levels. These molecules are crucial in several physiological functions, including cell division, cell proliferation, apoptosis, necrosis, cell migration, and lipid transport. Our study paves the pathway to study H. pylori and EBV co-infection in human gastric epithelial cells and the therapeutic interventions of WSE in this scenario and highlights specific biomolecular alterations, which can be focused for further mechanistic investigations.