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- Author or Editor: K. Das x
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Abstract
Liquid-liquid extractions of zirconium(IV) from aqueous HCl solutions by mixtures of Aliquat 336 or Alamine 336 and diocytl sulfoxide (DOSO) in the diluent benzene has been found to be always higher than that by any single extractant. While the cationic extractants extract Zr(IV) above 6M HCl, DOSO extracts from 4M onwards. Synergism has been observed in all cases. With any of these extractants extraction becomes almost quantitative at and above 10M HCl, but with mixtures of the cationic and neutral extractants, extraction is quantitative in the range 8–9M HCl. Although the extracted species with DOSO alone seems to be ZrCl4·DOSO, with the mixture of extractants, however, the extracted species appear to be Q2ZrCl6·DOSO where Q is R3 +NH (for Alamine 336) and R3 +N(CH3) (for Aliquat 336). Studies on separation of95Zr–95Nb pair from aqueous HCl media by Alamine 336 or DOSO and their mixtures in benzene exhibit preferential extraction of95Nb leaving behind95Zr in the aqueous phase, and extractions have been found to depend both upon the extractant and HCl concentrations.
Abstract
Two single doses of X-ray radiation, i.e., 75 cGy and 4.0 Gy were applied on male Swiss albino mice. Quantitative changes in concentrations of trace metals like copper, zinc, cadmium and chromium in the whole body irradiated mice skin at several post-irradiated time intervals were studied in comparison to that of control animals. Observations indicate that irradiation induce redistribution of trace metals studied in skin at different post-irradiation time intervals.
Abstract
Presence of thiocyanate ions results in appreciable extraction of Zr(IV) by Aliquat 336 from low aqueous HCl acidities, i.e., 0.1 to 4.5M. The variation of concentrations of HCl, thiocyanate and Aliquat 336 greatly influences the extent of extraction. Mixtures of Aliquat 336 and TOPO result in synergistic extraction of Zr and Hf from acidic thiocyanate media, the extracted species being the disolvate with TOPO. By controlled adjustment of HCl, SCN– and Aliquat 336 concentrations, separation of Zr, Nb and Hf is possible. A maximum separation factor (DNb/DZr) of 3675 has been achieved under certain conditions.
Abstract
In the study, four potent Lactobacillus cultures of L. rhamnosus K4E, L. plantarum RD7, L. fermentum K7, and L. fermentum K16 were considered for the production of B-vitamins, organic acids and biotransformation of soy isoflavones. L. plantarum RD7 showed the highest B2 production (0.84 μg mL−1) after 36 h, while L. fermentum K16 exhibited maximum B12 production (0.084 μg mL−1) after 12 h. L. rhamnosus K4E produced 0.24 μg mL−1 of folate after 12 h. Highest production of lactate (16.43 μg mL−1) and acetate (5.86 μg mL−1) was reported by L. rhamnosus K4E. L. plantarum RD7 showed maximum butyrate (0.253 μg mL−1) production compared to the other cultures. The highest bioconversion of soy aglycones was reported by L. rhamnosus K4E with 55.43% for daidzein and 72.30% for genistein, during soymilk fermentation. These potent cultures have a potential to be used as functional starter cultures for the production of functional fermented soy foods.
Abstract
The beach placer deposit at Chhatrapur coast of Orissa state, southeastern coast of India, has a significant concentration of radiogenic heavy minerals. The average activity concentrations of radioactive elements such as 232Th, 238U and 40K were measured by gamma ray spectrometry using a HPGe detector, and found to be 2650±50, 400±30 and 120±30 Bq/kg, respectively, for the bulk sand samples. The activity concentrations in monazite and zircon sands are found to be 305,000±2000 and 2000±150 Bq/kg for the 232Th and 21,500±300 and 3450±250 Bq/kg for the 238U. Electron probe microanalysis results of monazite sands show the average ThO2 and UO3 concentrations to be 10.42 wt.%, and 0.32 wt.%, respectively. The major contributors for the enhanced level of radioactivity are monazite and zircon sands. These heavy mineral sands were derived from the nearby source areas such as Eastern Ghats Group of rocks.
Abstract
Chitosan tripolyphosphate (CTPP) beads were prepared at two different cross-linking densities and adsorption of Cr(III) onto it were studied as a function of different operational parameters such as solution pH, equilibration time and initial Cr(III) ion concentration. Higher cross-linked beads were found to have more adsorption capacity at all the experimental pH employed (pH = 3–5), whereas adsorption capacity is found to increase with increase in pH. Adsorption data were analyzed using Langmuir and Freundlich isotherm models. Langmuir model is found be more suitable to explain the experimental results with a monolayer adsorption capacity of 469.5 mg/g. Among the kinetic models used, pseudo-second order kinetic model could best describe the adsorption process. Competition experiments done in presence of Na(I), Mg(II), Ca(II), Al(III) and Fe(III) revealed that, except in the case of Al(III), adsorption of Cr(III) is not significantly affected by the presence of foreign cations. NaCl is found to be a suitable leaching agent for the desorption of adsorbed Cr(III) from CTPP beads. FTIR spectroscopic investigations confirmed that phosphate groups are the principal binding site responsible for the sorption of Cr(III) onto CTPP beads.
Calcium plays an important role in the regulation of different functions of keratinocytes. In the present work we studied the effect of different extracellular calcium concentrations (0.01 mM-2.0 mM) on the proliferation and differentiation of human keratinocytes in normal human and non-lesional psoriatic skin. Using explant culture model, the proliferative and differentiated subsets of keratinocytes were detected by specific antibodies related to cell proliferation [beta-1 integrin (CD29), proliferating cell antigen (Ki67), proliferating cell nuclear antigen (PCNA)] and differentiation [differentiated cell cytokeratins (K1/K10) and differentiating cell antigen (lectin Ulex europaius agglutinin, UEA-1)]. After 4 days of culturing at high Ca2+ (2.0 mM) we observed marked hyperproliferation among the normally quiescent keratinocytes of non-lesional psoriatic skin. In normal uncultured and cultured skin and in uncultured and two-day-cultured non-lesional psoriatic skin both at normal (1.2 mM) and at high (2.0 mM) Ca2+ concentration only one layer of basal CD29+/Ki67+/K1/K10-/UEA-1- cell was observed. In sections from non-lesional psoriatic skin cultured for 4 days in the presence of high Ca2+ (2.0 mM) this cell population has expanded from at least three layers above the basement membrane. This expanded cell population of the 4-day high Ca2+ cultured non-lesional skin showed clear PCNA positive staining on frozen sections with the strongest positivity among the most basal localized cells. These data suggest that (i) extracellular Ca2+ concentration can influence the proliferation of basal ("stem") keratinocytes, (ii) the proliferative response to high Ca2+ concentration of psoriatic non-lesional basal keratinocytes differs from that of normal basal keratinocytes, (iv) changes in the extracellular Ca2+ milieu might play a role in the induction of the hyperproliferative psoriatic lesion.
Present study demonstrated the isolation of most promising β-galactosidase producing bacterial strain SB from soil. Morphological, biochemical, and 16s rRNA sequence analysis identified the bacterial strain as Arthrobacter oxydans. Several chemicals, including SDS, Triton X-100, Tween 20, isoamyl alcohol, and toluene-acetone mixture, were applied for extraction of intracellular β-galactosidase from the bacterial strain Arthrobacter oxydans. Among these, Tween 20 was recorded to be most effective. Role of pH, temperature, and shaker speed on production of β-galactosidase was evaluated using Box-Behnken design of response surface methodology. According to Box-Behnken analysis, optimum production of β-galactosidase (21.38 U (mg–1 protein)) is predicted at pH 6.76, temperature 36.1 °C, and shaker speed 121.37 r.p.m. The parameters are validated with the nearest value.
Abstract
A new CrIII–Schiff base complex of N,N′-ethylene-bis-salicylamide (Salm), supported on acidic alumina, was characterized by chemical and spectral (UV–Vis-DRS and FT-IR) analyses. The comparative catalytic activity of the neat and supported metal complex was evaluated using H2O2 decomposition as the model reaction at varying H2O2 concentration and amount of catalyst which showed a higher activity for the supported metal complex. A preliminary study showed that the supported CrIII(Salm) was also active for the oxidation of phenol using H2O2 as oxidant leading to catechol (selectivity ∼62%) and hydroquinone (selectivity ∼32%) as the major products.
Abstract
Ion-chromatography (IC) as well as high performance liquid chromatography (HPLC) techniques have been used as analytical tools for the separation and estimation of some of the relevant metal ions present in the high level liquid waste (HLLW). IC was applied for the estimation of alkali and alkali earth metal ions, viz. Na, Cs, Ba and Sr using methane sulphonic acid as the eluent on a cation exchange column. On the other hand, dynamically modified (with sodium salt of n-octane sulphonic acid) reverse phase HPLC was followed for the estimation of lanthanides viz. La, Pr, Nd and Sm using α-hydroxy isobutyric acid as the eluent on a C-18 column. Sample acidity of 0.01 M HNO3 was optimized for best analytical results. The interferences of one group of metal ions on the quantification of the other group of metal ions were studied. The solvent extraction data (distribution coefficient data) of Na, Cs, Sr, Ba, La, Pr, Nd and Sm from their mixture was obtained by analyses of the aqueous samples before and after extraction with extractants used for actinide partitioning, viz., octyl(phenyl)N,N-diisobutyl carbamoyl methylene phosphine oxide (CMPO), N,N′-dimethyl-N,N′-dibutyl tetradecyl malonamide (DMDBTDMA) and N,N,N′,N′-tetraoctyl diglycolamide (TODGA). The solvent extraction data obtained by IC/HPLC techniques was compared with those obtained by ICP-AES technique. A good agreement between the results of the two techniques validated the present analytical method.
