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11.
An environment friendly method for the synthesis of 2-oxo/thioxooctahydroquinazolin-5-one derivatives has been devised using Ceric ammonium nitrate (CAN) as catalyst and polyethylene glycol (PEG) as solvent. The cytotoxic effect of these compounds was studied on U87 human glioma cells, compounds 4c, 4d and 4e are found to exhibit excellent activity at a concentration as low as 0.06 μg/ml. 相似文献
12.
Bhattacharya M Jain N Bhasne K Kumari V Mukhopadhyay S 《Journal of fluorescence》2011,21(3):1083-1090
Serum albumins are multi-domain all α-helical proteins that are present in the circulatory system and aid in the transport
of a variety of metabolites, endogenous ligands, drugs etc. Earlier observations have indicated that serum albumins adopt
a range of reversible conformational isomers depending on the pH of the solution. Herein, we report the concurrent changes
in the protein conformation and size that are inherent to the pH-induced conformational isomers of bovine serum albumin (BSA).
We have investigated the fluorescence properties of both intrinsic (tryptophan) and extrinsic (ANS, pyrene) fluorophores to
shed light into the structural features of the pH-dependent conformers. We have been able to identify a number of conformational
isomers using multiple fluorescence observables as a function of pH titration. Our results indicate that at pH 3, a partially-folded,
‘molten-globule-like’ state is populated. Moreover, equilibrium unfolding studies indicated that the ‘molten-globule-like’
state unfolds in a non-cooperative fashion and is thermodynamically less stable than the native state. The fluorescence-based
approach described in the present work has implications in the study of pH-induced conformational plasticity of other physiologically
relevant proteins. 相似文献
13.
Thermoluminescence (TL) and electron spin resonance (ESR) studies of γ-ray and pile-irradiated natural barite have led to the identification of centres which act as electron or hole traps. Intense pile irradiation seems to help the formation of the S2O3-radical. The presence of cation vacancies, as indicated by TL glow curves, makes pile-irradiated (>1018 n cm-2 samples “immune” to further γ-irradiations as far as TL and ESR are concerned. 相似文献
14.
D.?P.?SinghEmail author Ramesh?Kumar Vandna?Malik Parikshit?Tyagi 《Transition Metal Chemistry》2007,32(8):1051-1055
A new series of complexes is synthesized by template condensation of glyoxal and oxalyldihydrazide in methanolic medium in
the presence of divalent cobalt, nickel, copper, zinc and cadmium salts forming complexes of the type: [M(C8H8N8O4)X2] where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl−1, Br−1, NO
3
−1
, OAc−1. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility
measurements, electronic, n.m.r., infrared and far infrared spectral studies. On the basis of these studies, a six coordinate
octahedral geometry for these complexes has been proposed. The biological activities of the metal complexes have been tested
in vitro against a number of pathogenic bacteria to assess their inhibiting potential. Most of the compounds have been found to exhibit
remarkable antibacterial activities. 相似文献
15.
Teare H Robins EG Arstad E Luthra SK Gouverneur V 《Chemical communications (Cambridge, England)》2007,(23):2330-2332
A novel [18F]NF reagent and two novel radiochemical transformations have been developed: [18F]NFSi has been prepared from sodium dibenzenesulfonimide and reacted in the presence of silyl enol ethers and allylsilanes to deliver labelled fluorinated ketones and allylic fluorides respectively; the radiosynthesis of the fluorinated A ring of vitamin D3 has also been completed with success. 相似文献
16.
Anupama Sachdeva Mahesh Kumar Vandna Luthra R. P. Tandon 《Applied Physics A: Materials Science & Processing》2011,104(1):103-108
We report here the formation of single phase lead zirconate titanate (PZT) nanopowder with composition Pb(Zr0.52Ti0.48)O3 and average crystallite size 12?C20?nm, synthesized by sol?Cgel process. The phase evolution of PZT gel powder, heat treated at temperatures 550, 650 and 800°C was monitored by X-ray diffraction (XRD) and X-ray photo-electron spectroscopy (XPS). The high resolution XPS spectra of Pb4f, Zr3d, Ti2p and O1s show that PZT with pure perovskite structure is obtained at 800°C while at lower temperatures pyrochlore phase co-exists with perovskite phase. The XRD results also support this analysis. We have also identified the pyrochlore phase using XPS by analyzing the corresponding variations in the FWHM values, peak positions and the separation between the spin doublets of Pb, Zr and Ti associated with it. The composition of the final powder obtained with pure perovskite structure is calculated and is close to the designed value. 相似文献
17.
Thermoluminescence, TL emission spectra, ESR and optically excited luminescence of BaSO4:Sm and BaSO4:Eu were investigated. The optically excited luminescence studies showed that samarium ions were stabilized in the trivalent state in doped samples, and a fraction of these ions was reduced to the divalent state on γ-irradiation. These reduced ions were reoxidized on thermal annealing. Europium was found to be stabilized in the divalent form in BaSO4:Eu phosphor, both before and after γ-irradiation. These results were further confirmed from the emission spectra of different glow peaks from BaSO4:Sm and BaSO4:Eu samples. The ESR spectra of these samples, recorded after γ-irradiation and various post-irradiation thermal annealings, revealed that anion radicals (such as SO4?, SO3?, SO2+ and O3?) are formed on γ-irradiation and get annihilated at temperatures which corresponds to some of the glow peaks. An attempt is made to explain the results by a mechanism, suggested earlier for other impurity-doped BaSO4 phosphors, in which holes released on thermal activation from anion radicals recombine with the electrons trapped at certain defect centres and the energy thus released is non-radiatively transferred to the impurity ions, which give their characteristic emission. 相似文献
18.
L.K. Misra S.R. Kasturi S.K. Kundu Y. Harati C.F. Hazlewood M.G. Luthra W.S. Yamanashi R.P. Munjaal S.R. Amtey 《Magnetic resonance imaging》1982,1(2):75-79
Nuclear magnetic resonance (NMR) techniques were applied to study the muscular dystrophy in chicks. The water proton spin-lattice relaxation times (T1) of fast, slow, and mixed muscles and plasma were measured. The T1 values of dystrophic pectoralis major and posterior latissimus dorsi (PLD) were significantly higher than those of the normal pectoralis and PLD muscles. The present results establish a direct relationship between the differences in T1 values and the severity of muscle degeneration. Consistent with this conclusion, it was also found that the T1 values of muscles unaffected in muscular dystrophy, namely, the gastrocnemius, and anterior latissimus dorsi (ALD), were not different between the normal and dystrophic chicks. Although the affected muscles of dystrophic chicks contained higher percent water and fat than those of normal chicks, the results show that the higher T1 values is dystrophic muscles were not solely due to variations in their water content. The increase in the T1 values is principally a result of altered interaction between cellular water and macromolecules in the diseased muscles. These data also point out the potential use of NMR imaging in evaluating muscle degeneration. 相似文献
19.
Rapid Aqueous Late‐Stage Radiolabelling of [GaF3(BnMe2‐tacn)] by 18F/19F Isotopic Exchange: Towards New PET Imaging Probes
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Francesco M. Monzittu Imtiaz Khan Prof. William Levason Dr. Sajinder K. Luthra Dr. Graeme McRobbie Prof. Gillian Reid 《Angewandte Chemie (International ed. in English)》2018,57(22):6658-6661
A simple and rapid method for 18F radiolabelling of [GaF3(BnMe2‐tacn)] by 18F/19F isotopic exchange is described. The use of MeCN/H2O or EtOH/H2O (75:25) and aqueous [18F]F? (up to 200 MBq) with heating (80 °C, 10 min) gave 66±4 % 18F incorporation at a concentration of 268 nm , and 37±5 % 18F incorporation at even lower concentration (27 nm ), without the need for a Lewis acid promoter. A solid‐phase extraction method was established to give [Ga18F19F2(BnMe2‐tacn)] in 99 % radiochemical purity in an EtOH/H2O mixture. 相似文献
20.
Kumar Rajesh Kumari Ruchi Khan Lubina Sankhyan Anurag Parray Hilal Ahmad Tiwari Ashutosh Wig Naveet Sinha Subrata Luthra Kalpana 《Applied biochemistry and biotechnology》2019,187(3):1011-1027
Applied Biochemistry and Biotechnology - Recently conducted human phase- I trials showed protective effect of anti-HIV-1 broadly neutralizing antibodies (bnAbs). The V3 region of the HIV-1 envelope... 相似文献