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11.
H. B. Desai P. K. Padmanabhan Ch. Venkateswarlu 《Journal of Radioanalytical and Nuclear Chemistry》1976,31(2):525-527
Copper in distilled water is collected on Zeokarb 226(NH
4
+
) and irradiated with thermal neutrons. By comparison of the induced activity of 0.51 MeV photopeak of64Cu with that of a standard, irradiated under comparable conditions, copper at ppb levels is easily determined. 相似文献
12.
The ring-closing metathesis reactions (RCM) of six standard diene substrates leading to five-, six-, or seven-membered carbo- or heterocycles were investigated under controlled microwave irradiation. RCM protocols were performed with standard Grubbs type II and a cationic ruthenium allenylidene catalyst in neat and ionic liquid-doped methylene chloride under sealed vessel conditions. Very rapid conversions (15 s) were achieved utilizing 0.5 mol % Grubbs II catalyst under microwave conditions. Careful comparison studies indicate that the observed rate enhancements are not the result of a nonthermal microwave effect. 相似文献
13.
Nguyen Van Suc H. B. Desai R. Parthasarathy S. Gangadhaŕan 《Journal of Radioanalytical and Nuclear Chemistry》1992,164(5):321-325
Individual rare earth impurities in high purity La2O3 (99.9%) have been determined by NAA after pre-separation of the matrix (La). The separation is carried out on an anion exchanger (Dowex 1×8) using different mixtures of methanol/nitric acid as eluants. The rare earth elements from Dy to Lu are eluted quantitatively using a 10% 1M HNO3-90% methanol mixture, while the light rare earths from Ce to Gd are eluted quantitatively using a 10% 0.05M HNO3-90% methanol mixture. La, which is retained on the column, is eluted using 0.1M HNO3. The recoveries of the various rare earth elements have been checked using radiotracers and also by spiking the sample with known amount of elements, and the recoveries are found to be quantitative. Results obtained on a typical high purity lanthanum oxide are reported here. 相似文献
14.
We consider a binary fluid mixture made up of a monatomic species and a two level molecular species and investigate the decay of correlations in the hydrodynamic variables. By restricting our considerations to the translationally hydrodynamic situations, we deduce a set of generalised hydrodynamic equations in which the frequency, ω, and wavenumber, k, dependent memory arises solely from the internal molecular relaxation. From these generalised hydrodynamic equations, we identify various (k, ω) dependent transport coefficients and the relaxation time which depends on k. We also compute the spectrum of (polarised) light scattered from such a binary mixture. We illustrate the dependence on k, ω and concentration in the problem by a numerical calculation of the generalised transport coefficients, the Rayleigh-Brillouin spectrum and the dispersion of various modes in this spectrum for the case of thermal relaxation in a parahydrogen-helium mixture. 相似文献
15.
16.
Kuo-yuan Hung Renata Kowalczyk Ami Desai Margaret A. Brimble John F. Marshall Paul W. R. Harris 《Molecules (Basel, Switzerland)》2022,27(14)
A20FMDV2 is a 20-mer peptide that exhibits high selectivity and affinity for the tumour-related αvβ6 integrin that can compete with extracellular ligands for the crucial RGD binding site, playing a role as a promising αvβ6-specific inhibitor for anti-cancer therapies. Unfortunately, the clinical value of A20FMDV2 is limited by its poor half-life in blood caused by rapid renal excretion and its reported high susceptibility to serum proteases. The incorporation of poly (ethylene glycol) chains, coined PEGylation, is a well-established approach to improve the pharmacokinetic properties of drug molecules. Here, we report a systematic study on the incorporation of a varying number of ethylene glycol units (1–20) into the A20FMDV2 peptide to establish the effects of PEGylation size on the peptide stability in both rat serum and human plasma. In addition, the effect of acetyl and propionyl PEGylation handles on peptide stability is also described. Selected peptide analogues were assessed for integrin-αvβ6-targeted binding, showing good specificity and activity in vitro. Stability studies in rat serum established that all of the PEGylated peptides displayed good stability, and an A20FMDV2 peptide containing twenty ethylene glycol units (PEG20) was the most stable. Surprisingly, the stability testing in human plasma identified shorter PEGs (PEG2 and PEG5) as more resistant to degradation than longer PEGs, a trend which was also observed with affinity binding to integrin αvβ6. 相似文献
17.
C. P. Bhasin J. P. Patel M. L. Desai 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2509-2524
Dialkyldithiophosphate derivatives of macrocyclic complexes of Pb(II), having N2S2 potential donors, of the general formula, [Pb(L)S2P(OR)2] (where L = macrocyclic ligands L1, L2, L3, L4 & L5 and R = CH3-, C3H7 n- & C3H7 i-) have been Synthesized from the reactions of [Pb(L)X2] (where X = Cl, NO3, or CH3COO) with sodium dialkyl dithiophosphates in 1:2 molar ratios in THF. Fifteen new derivatives have been synthesized by the combination of five macrocyclic complexes of 14–20 member rings with three different types of dialkyldithiophosphate. These compounds have been characterized by elemental analysis, molar conductance, molecular weight determination, IR, 1H NMR, 13C, and 31P NMR. Molecular weight determinations of these complexes indicate their monomeric nature. An octahedral structure is proposed. 相似文献
18.
Abstract The films of poly(4,4′-cyclohexylidene diphenylene-m-benzene disulfonate) (PSBB, 0.610 mm thick) and poly(4,4′-cyclohexylidene diphenylene-toluene-2,4-disulfonate) (PSBT, 0.537 mm thick) showed 8.23 ± 0.25 and 9.6 ± 0.245 kV, respectively, as the dielectric breakdown voltage (ac) in air at room temperature. The same films have 8.8 × 1011 and 7.2 × 1014 ω°Cm volume resistivity. PSBB (40 μm thick) and PSBT (50 μm thick) films have tensile strengths of 1971 and 1677 kg/cm2 and percent elongations of 1.3 and 1.2, respectively. The static hardnesses of PSBB (0.178 mm thick) and PSBT (0.190 mm thick) at three different loads (15–60 g) are 12.8–15.5 and 14.5–16.5 kg/mm2, respectively. PSBB and PSBT are thermally stable up to about 355°C in an N2 atmosphere and involve two-step degradation. DSC and DTA showed T g at about 125–127 and 138–142°C, respectively, for PSBB and PSBT in N2. PSBB and PSBT have comparable breakdown voltages and volume resistivity with some useful plastics whereas they have superior T g and thermal stability with retention of excellent solubility in common solvents over polysulfonates without a cardo group. Thus, the cardo (cyclo-hexyl) group has enhanced thermal and mechanical properties with excellent solubility and easy processing. 相似文献
19.
Solid–liquid phase‐transfer conditions were employed for the first time in the Thorpe reaction to synthesize 4‐amino‐1‐aryl‐3,5‐substituted‐1H‐pyrazoles 3. Aryl amines were diazotized and coupled with various active methylene compounds such as cyano acetamide, cyanoacetophenone, malononitrile, and ethyl cyanoacetate, resulting into α‐arylhydrazononitriles 1. Cyclization of 1 using α‐bromo ketones or esters resulted in compounds 3. 相似文献
20.
Desai Nisheeth C. Vaja Darshita V. Joshi Surbhi B. Khedkar Vijay M. 《Research on Chemical Intermediates》2021,47(2):573-587
Research on Chemical Intermediates - We have developed a simple synthetic protocol for the preparation of novel 3-(3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl)-5-arylisoxazoles. The structure of... 相似文献