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81.
Chirag K. Vyas Pranav M. Joshirao H. Bagla Vijay K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):1643-1650
An attempt has been made in the present work to investigate the role of anion for the uptake of Am(III)/Eu(III)/U(VI) by extraction chromatography (EXC) resin incorporating tetra-n-octyl-3-oxapentanediamide, commonly referred to as tetra-octyl diglycolamide (TODGA). In contrast to the nitric acid, perchloric acid medium favors extraction of trivalent metal ions even at low acidity (pH 2) and is almost insensitive to the acidity up to 5 M. Exceptionally large distribution coefficients (105–106) in the wide range of perchlorate concentration (10?2–5 M) is quite unusual and is by far the largest reported in the literature for Am(III)/Eu(III). Thermodynamic data suggests the possibility of inner sphere/cation exchange mechanism involving TODGA aggregates at higher acidity but outer sphere/cation exchange mechanism at low acidity for Eu(III). There is a possibility of employing TODGA based EXC resin for the remediation of liquid waste (contaminated with long lived transuranics like 241/243Am and 245Cm) in the wide range of acidity. 相似文献
82.
Some novel adsorbents were prepared by rice husk (RH). The esterified rice husk (RHS) was prepared by treating RH with anhydride of succinic acid to introduce carboxylic function to rice husk. This RHS was used to anchor various polyamines, viz., ethylenediamine (ED) and diethylenetriamine (DT) to prepare new adsorbents. These adsorbents were used to separate Pt(IV) from synthetic as well as industrial wastewaters. Adsorbents were characterized by Fourier transform infrared spectra, elemental analysis, scanning electron microscopy, and energy dispersive x-ray spectrometry. The selectivity order for Pt(IV) removal found was: RHS-DT > RHS-ED > RH > RHS. The Freundlich isotherm provided the high correlation (0.9750–0.9938) for the adsorption with low SSE (0.00215–0.00785) value of Pt(IV) for all the adsorbents. Among the kinetic models, pseudo-second order kinetic model was found to best fit with high correlation for all the adsorbents. The results of thermodynamic parameters suggest that the Pt(IV) adsorption was spontaneous and endothermic in nature. The maximum percentage of desorption of Pt(IV) metal ion was obtained when the reagent HCl–thiourea mixture was used as desorbing agent. 相似文献
83.
Chirag K. Vyas Pranav M. Joshirao Vijay K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(1):445-450
The distribution coefficient measurements on Y(III) and Sr(II) were performed using ditertiarybutyl dicyclohexano 18-crown-6 (Sr-selective resin) and N,N,N′,N′-tetraoctyldiglycolamide (Y-selective resin) in HNO3, HCl and HClO4 media. Separation factors (90Y/90Sr) based on distribution coefficient data suggested that perchloric acid is distinctly better medium as compared to nitric acid/hydrochloric acid. The mechanism of extraction changes with the nature and concentration of acid and is responsible for the high selectivity in perchloric acid medium. Sequential column studies were carried out on tracers (radioactive/stable) employing Sr-selective/Y-selective extraction chromatographic resins as stationary phases. The final elution of 90Y was done in 0.01 M EDTA at pH 4.0 which can be used for clinical applications after radiochemical processing. 相似文献
84.
We present diverse reconfigurable complex 3D twister vortex superlattice structures in a large area embedded with tunable vortex spirals as well as dark rings, threaded by vortex helices. We demonstrate these tunable complex chiral vortex superlattices by the superposition of relatively phase engineered plane waves. The generated complex 3D twister lattice vortex structures are computationally as well as experimentally analyzed using various tools to verify the presence of phase singularities. Our observation indicates the application-specific flexibility of our approach to tailor the transverse superlattice spatial irradiance profile of these longitudinally whirling vortex-cluster units and dark rings. 相似文献
85.
Charmaine Arderne Kyle Fraser Batchelor Bhawna Uprety Rahul Chandran Heidi Abrahamse 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(7):663-672
The reactivity of the cobalt(III) complexes dichlorido[tris(2‐aminoethyl)amine]cobalt(III) chloride, [CoCl2(tren)]Cl, and dichlorido(triethylenetetramine)cobalt(III) chloride, [CoCl2(trien)]Cl, towards different amino acids (l ‐proline, l ‐asparagine, l ‐histidine and l ‐aspartic acid) was explored in detail. This study presents the crystal structures of three amino acidate cobalt(III) complexes, namely, (l ‐prolinato‐κ2N,O)[tris(2‐aminoethyl)amine‐κ4N,N′,N′′,N′′′]cobalt(III) diiodide monohydrate, [Co(C5H8NO2)(C6H18N4)]I2·H2O, I , (l ‐asparaginato‐κ2N,O)[tris(2‐aminoethyl)amine‐κ4N,N′,N′′,N′′′]cobalt(III) chloride perchlorate, [Co(C4H7N2O3)(C6H18N4)](Cl)(ClO4), II , and (l ‐prolinato‐κ2N,O)(triethylenetetramine‐κ4N,N′,N′′,N′′′)cobalt(III) chloride perchlorate, [Co(C4H7N2O3)(C6H18N4)](Cl)(ClO4), V . The syntheses of the complexes were followed by characterization using UV–Vis spectroscopy of the reaction mixtures and the initial rates of reaction were obtained by calculating the slopes of absorbance versus time plots. The initial rates suggest a stronger reactivity and hence greater affinity of the cobalt(III) complexes towards basic amino acids. The biocompatibility of the complexes was also assessed by evaluating the cytotoxicity of the complexes on cultured normal human fibroblast cells (WS1) in vitro. The compounds were found to be nontoxic after 24 h of incubation at concentrations up to 25 mM. 相似文献
86.
In this study we designed novel substituted benzimidazole derivatives and predicted their absorption, distribution, metabolism, excretion and toxicity (ADMET) properties, based on a predictive 3D QSAR study on 132 substituted benzimidazoles as AngII–AT1 receptor antagonists. The two best predicted compounds were synthesized and evaluated for AngII–AT1 receptor antagonism. Three different alignment tools for comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were used. The best 3D QSAR models were obtained using the rigid body (Distill) alignment method. CoMFA and CoMSIA models were found to be statistically significant with leave-one-out correlation coefficients (q2) of 0.630 and 0.623, respectively, cross-validated coefficients (r2cv) of 0.651 and 0.630, respectively, and conventional coefficients of determination (r2) of 0.848 and 0.843, respectively. 3D QSAR models were validated using a test set of 24 compounds, giving satisfactory predicted results (r2pred) of 0.727 and 0.689 for the CoMFA and CoMSIA models, respectively. We have identified some key features in substituted benzimidazole derivatives, such as lipophilicity and H-bonding at the 2- and 5-positions of the benzimidazole nucleus, respectively, for AT1 receptor antagonistic activity. We designed 20 novel substituted benzimidazole derivatives and predicted their activity. In silico ADMET properties were also predicted for these designed molecules. Finally, the compounds with best predicted activity were synthesized and evaluated for in vitro angiotensin II–AT1 receptor antagonism. 相似文献
87.
H. O. Jethva P. M. Vyas K. P. Tank M. J. Joshi 《Journal of Thermal Analysis and Calorimetry》2014,117(2):589-594
Metal tartrate compounds find various applications. Lead tartrate is added in gasoline to prevent knocking in motors, and cadmium tartrate crystals possess piezoelectric nature. In the present study, lead–cadmium-mixed levo tartrate crystals were grown using silica hydro gel as growth medium. Long and dendrite-type white crystals were obtained. The crystals were characterized by EDAX, powder XRD, FTIR spectroscopy, TG, DTA, and DSC. The composition of the crystals was determined by EDAX. The FTIR spectra revealed the presence of water molecules, O–H, C–H, C–O, C–C, and C=O functional groups. TG curves suggested that the crystals were thermally unstable and decomposed into oxide through three stages. DTA curves showed endothermic and exothermic reactions. 相似文献
88.
Vashistha Vinod Kumar Kumar Anuj Das Dipak Kumar Alwera Shiv Vyas Renu Sharma Vivek Sethi Sonika Pullabhotla Rajasekhar Nagar Hariom 《平面色谱法杂志一现代薄层色谱法》2021,34(3):211-215
JPC – Journal of Planar Chromatography – Modern TLC - This work reports the enantioresolution of (RS)-acebutolol (ACB) by a thin-layer chromatographic method involving colistin sulfate... 相似文献
89.
Recently we discovered several new Erdélyi type integrals. In the present paper, it is shown how the q-extensions of all those integrals involving and representing certain q-hypergeometric functions can be developed. The well-known special cases and applications of these q-integrals are also pointed out. 相似文献
90.
Rashmi Tyagi G. Srinivas Deepak Vyas Ashok Kumar H. D. Kumar 《Photochemistry and photobiology》1992,55(3):401-407
The impact of UV-B radiation on growth, pigmentation and certain physiological processes has been studied in a N2-fixing chromatically adapting cyanobacterium, Nostoc spongiaeforme. A brownish form (phycoerythrin rich) was found to be more tolerant to UV-B than the blue-green (phycocyanin rich) form of N. spongiaeforme. Continuous exposure to UV-B (5.5 W m-2) for 90 min caused complete killing of the blue-green strain whereas the brown strain showed complete loss of survival after 180 min. Pigment content was more strongly inhibited in the blue-green strain than in the brown. Nitrogenase activity was completely abolished in both strains within 35 min of UV-B treatment. Restoration of nitrogenase occurred upon transfer to fluorescent or incandescent light after a lag of 5-6 h, suggesting fresh synthesis of nitrogenase. Unlike the above processes, in vivo nitrate reductase activity was stimulated by UV-B treatment, the degree of enhancement being significantly higher in the blue-green strain. Like the effect of UV-B on nitrogenase, 14CO2 uptake was also completely abolished by UV-B treatment in both strains. Our findings suggest that UV-B may produce a deleterious effect on several metabolic activities of cyanobacteria, especially in cells lacking phycoerythrin. Strains containing phycoerythrin appear to be more tolerant to UV-B, probably because of their inherent property of adapting to a variety of light qualities. 相似文献