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141.
The aggregation behavior of cetylpyridinium chloride (CPyCl) in N,N-dimethylformamide (DMF)-water mixed solvents was investigated using electrical conductivity and spectroscopic techniques. Micellar and thermodynamic parameters (DeltaG(m)(0), DeltaH(m)(0), DeltaS(m)(0) and Delta(m)C(p)(0)) were obtained from the temperature dependence of critical micelle concentrations in various aqueous mixtures of DMF. The differences in the Gibbs energies of micellization of CPyCl between water and binary solvents were determined to evaluate the influence of the cosolvent. The effect of cosolvent on the Krafft temperature (K(T)) and on the aggregation number was also analyzed. Micellar micropolarity was examined spectrophotometrically using two different probes, methyl orange (MO) and methylene blue (MB), and was found to increase with DMF addition, accompanied by an enhanced solvation. The mechanism of docking of surfactant and the probe molecules in the system were obtained by using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. 相似文献
142.
One Pot Regioselective Synthesis and Antimicrobial Studies of Some Novel Indazolyl–Thiazole Derivatives
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2‐Benzylidene‐1‐tetralones, obtained via Claisen condensation of 1‐tetralones with aromatic aldehydes, in one pot condensation with thiosemicarbazide/semicarbazide and α‐haloketones in the presence of trifluoroethanol and conc. HCl gives rise to a series of new substituted‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazol‐2yl‐thiazoles. The condensation was also carried out in two steps, and the intermediates 3‐substituted‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamides/carboxamides, obtained in the first step by the reaction of 2‐bezylidene‐1‐tetralones with thiosemicarbazide/semicarbazide, on reaction with α‐haloketones gives rise to indazolyl–thiazoles. A detailed X‐ray diffractometry of intermediate (3aR)‐3‐phenyl‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamide were carried out to establish its crystal structure. Further, density functional theory studies on (3aR)‐3‐phenyl‐3,3a,4,5‐tetrahydro‐2H‐benzo[g]indazole‐2‐carbothioamide and its regioisomer were carried out. There is good correlation between the theoretical and experimental spectral data. The antibacterial and antifungal activities of the selected compounds were examined, and some are found to exhibit excellent activities. 相似文献
143.
Razi MT Asad MH Khan T Chaudhary MZ Ansari MT Arshad MA Saqib QN 《Natural product research》2011,25(20):1902-1907
Plants have been extensively used as a remedy for the treatment of snake bites. The aim of this study was to determine the antivenom potentials of methanolic extract from the aerial parts (leaves and twigs) of Fagonia cretica L. on a haemorrhage induced by venom from Naja naja karachiensis. The haemorrhagic response of venom was dose dependent from 0.1 to 4.0?μg per 1.5?μL phosphate buffer saline (PBS) on vitelline veins of fertilised hens' eggs in their shells. The extract effectively eliminated and neutralised, in a dose-dependent manner, the haemorrhagic activity of snake venom. The minimum effective neutralising dose of F. cretica extract was found to be 15?μg per 1.5?μL PBS. The extract possesses potentials as haemorrhagic inhibitor against snake venom compared to the standard antiserum and various plants reported in the literature. This study also provides a scientific base for the use of F. cretica in traditional medicine for the treatment of snake bite. 相似文献
144.
Yadav VK Kumar V Chhikara N Kumar S Manral P Kashav T Saini S Srinivasan A Singh S Singh TP Yadav S 《Journal of separation science》2011,34(9):1076-1083
The seminal plasma comprises secretions from various accessory sex glands. During fertilization spermatozoa undergo complex sequences of precisely timed events that are regulated by the activation of different intracellular signaling pathways. The precision and efficacy of these pathways are often influenced by the assembly and interactions of multiprotein complexes, thereby directing the flow of regulatory information. Our knowledge about these protein complexes present in human seminal plasma (HuSP) is limited. Here we report the identification and characterization of a native high molecular weight zinc-binding multiprotein complex from HuSP by utilizing 2-DE followed by MS. Twenty-six proteins representing isoforms and/or fragments of 11 different proteins were found to be assembled in this complex. Prostate-specific antigen, zinc α2-glycoprotein, prostatic acid phosphatase, and prolactin inducible protein were the major proteins of this complex. Dynamic light scattering experiments revealed changes in aggregation pattern accompanied with deviation from physiological pH and in presence of SDS. However, no significant changes were observed in the presence of physiological ligands such as zinc and fructose. The present study will be useful and contribute to guide the future studies performed for elucidation of biological significance of this native complex in HuSP. 相似文献
145.
Archana Chaudhary Namita Sharma Veena Dhayal Arpita Saxena Meena Nagar Rakesh Bohra 《应用有机金属化学》2011,25(3):198-206
Some bis(cyclopentadienyl)titanium(IV) complexes of the type [Cp2TiCl2?n{L}n] {where, n = 1 or 2; L = ONC(R)Ar; R = H or CH3 and Ar = C5H4N‐2, C4H3O‐2 or C4H3S‐2} have been synthesized by the metathetical reactions of Cp2TiCl2 with the sodium salt of internally functionalized oximes in 1:1 and 1:2 stoichiometry in anhydrous THF. All these red to brown colored solid derivatives have been characterized by elemental analyses, FT‐IR and NMR (1H and 13C{1H}) spectral studies. The FAB mass spectra of some representative derivatives indicate their monomeric nature. Oximato ligands in all the complexes appear to bind the titanium via N and O in a dihapto ( ‐N, O) manner in the solid state. Thermogravimetric curves of [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] suggest the formation of hybrid materials CpTiO(Cl) and Cp2TiO, respectively, as the final products at 900 °C under nitrogen atmosphere. Sol–gel transformations of Cp2TiCl2, [Cp2TiCl{ONC(CH3)C5H4N‐2}] and [Cp2Ti{ONC(CH3)C5H4N‐2}2] yielded titania a–c, respectively, at low sintering temperature (600 °C). The powder XRD patterns, IR as well as Raman spectra of all these oxides indicate the formation of nano‐sized anatase phase. The SEM images of titania a–c indicate agglomers like surface morphologies. The absorption spectra of a–c exhibit an energy band gap in the range of 3.47–3.71 eV. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
146.
S.K. Rakshit S.C. Parida Ziley Singh Chaudhary 《Journal of solid state chemistry》2011,184(5):1186-1194
Thermodynamic studies on ternary oxides of Li-Fe-O systems were carried out using differential scanning calorimetry, Knudsen effusion mass spectrometry, and solid-state electrochemical technique based on fluoride electrolyte. Heat capacities of LiFe5O8(s) and LiFeO2(s) were determined in the temperature range 127-861 K using differential scanning calorimetry. Gibbs energies of formation of LiFe5O8(s) and LiFeO2(s) were determined using Knudsen effusion mass spectrometry and solid-state galvanic cell technique. The combined least squares fits can be represented as
ΔfGmo(LiFe5O8,s,T)/kJ mol−1 (±6)=−2341+0.6764(T/K) (588≤T/K≤971) 相似文献
147.
Subhabrata Sen Siva R. KammaVenkata R. Potti Y.L.N. Murthy Avinash B. Chaudhary 《Tetrahedron letters》2011,52(43):5585-5588
We report a facile diversity oriented synthesis of α- and β-amino acids, by utilizing the pluripotent α-methylene group in a chiral bicyclic lactam as our key point of transformation. 相似文献
148.
Kwak IH Shin YH Kim M Cha HY Nam HJ Lee BS Chaudhary SC Pai KS Lee JH 《Experimental & molecular medicine》2011,43(2):111-120
Aberrant activation of hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, Met, is involved in the development and progression of many human cancers. In the cell-based screening assay, (-)epigallocatechin-3-gallate (EGCG) inhibited HGF/SF-Met signaling as indicated by its inhibitory activity on HGF/SF-induced cell scattering and uPA activation (IC50=15.8 microgram/ml). Further analysis revealed that EGCG at low doses specifically inhibited HGF/SF-induced tyrosine phosphorylation of Met but not epidermal growth factor (EGF)-induced phosphorylation of EGF receptor (EGFR). On the other hand, high-dose EGCG decreased both Met and EGFR proteins. We also found that EGCG did not act on the intracellular portion of Met receptor tyrosine kinase, i.e., it inhibited InlB-dependent activation of Met but not NGF-induced activation of Trk-Met hybrid receptor. This inhibition decreased HGF-induced migration and invasion by parental or HGF/SF-transfected B16F10 melanoma cells in vitro in either a paracrine or autocrine manner. Furthermore, EGCG inhibited the invasion/metastasis of HGF/SF-transfected B16F10 melanoma cells in mice. Our data suggest the possible use of EGCG in human cancers associated with dysregulated paracrine or autocrine HGF/SF-Met signaling. 相似文献
149.
Yokraj Katre Savita Nayak D. N. Sharma Ajaya K. Singh 《Research on Chemical Intermediates》2012,38(1):179-193
The kinetics of micellar catalyzed oxidation of galactose by N-bromophthalimide was studied in the presence of acidic medium at 308?K. The oxidation reaction exhibits first-order kinetics with respect to oxidant (N-bromophthalimide), fractional order with respect to substrate (galactose) and positive fractional order with respect to HClO4 on the rate of reaction. The rate of the reaction increased with decreasing the dielectric constant of the medium. With a progressive increase in the concentration of CTAB, the rate of reaction increased and after reaching peak k obs, decreased at higher concentrations of CTAB. There catalytic roles are best explained by Berezin??s model. The influence of salts on the reaction rate was also studied. The various activation parameters have been calculated. The rate constant and binding constant with the surfactant have also been evaluated. A suitable mechanism consistent with the experimental findings has been proposed. 相似文献
150.
Ruby Chauhan Ashavani Kumar Ram Pal Chaudhary 《Journal of Sol-Gel Science and Technology》2012,61(3):585-591
Undoped and zinc-doped TiO2 nanoparticles (Ti1−xZnxO2 where x = 0.00–0.10) were synthesized by a sol–gel method. The synthesized products were characterized by X-ray diffraction
(XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and UV–VIS spectrometer. XRD pattern confirmed
the tetragonal structure of synthesized samples. Average grain size was determined from X-ray line broadening using the Debye–Scherrer
relation. The crystallite size was varied from 10 to 40 nm as the calcination temperature was increased from 350 to 800 °C.
The incorporation of 3–5 mol% Zn2+ in place of the Ti4+ provoked a slight decrease in the size of nanocrystals as compared to undoped TiO2. The SEM and TEM micrographs revealed the agglomerated spherical-like morphology with a diameter of about 10–30 nm and length
of several nanometers, which is in agreement with XRD results. Optical absorption measurements indicated a blue shift in the
absorption band edge upon 3–5 mol% zinc doping. Direct allowed band gap of undoped and Zn-doped TiO2 nanoparticles measured by UV–VIS spectrometer were 2.95 and 3.00 eV at 550 °C, respectively. 相似文献