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- Author or Editor: S. C. Sharma x
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The reversed-phase thin-layer chromatographic behavior of 3d metal ions has been studied on silica gel GF254 layers impregnated with silicone fluid DC200, tri-aryl phosphate, and tri-n-butyl phosphate; mixtures of DMSO and HNO3 were used as mobile phases. The effect of silicone fluid DC200 and of the tri-aryl phosphate ion on the R F values of the metal ions is discussed. Mobile phases prepared from DMSO and 1 M HNO3 are most effective when the concentration of acid in the mixed mobile phase is between 0.10 and 0.70 M. The mechanism of migration is explained in terms of adsorption and complex formation. The effect of solvent composition on the migration behavior of the metal ions was also studied. Some binary and ternary separations were achieved.
Present investigation reports the variability in phenolics and activities of some enzymes involved in their metabolism in pericarp tissue of ‘Calcuttia’ and ‘Seedless’ cultivars harvested at one week interval after fruit set. Total phenolics, flavonols, and phenolic acid contents in litchi fruit pericarp increased after 49 days following fruit set (DAFS), while proanthocyanins showed a small increment initially and then decreased significantly up to maturity. Polyphenol oxidase, phenylalanine ammonia lyase, and cinnamate-4-hydroxylase activities followed the similar trend as observed in phenolic content at respective developmental stages, while peroxidase activity in pericarp was low at initial stages and increased gradually with fruit development. Higher phenolic content with low polyphenol oxidase activity in pericarp during initial stages of fruit development in ‘Seedless’ as compared to ‘Calcuttia’ cultivar suggests the slow ripening. A negative correlation between anthocyanin content and anthocyanase activity was recorded. Total phenolic constituents, ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity showed positive correlation with higher values of these parameters in ‘Seedless’ as compared to ‘Calcuttia’ cultivar. Knowing the phenolic profiles, antioxidant activity, and activity of related enzymes during fruit development gives the insights into its potential application to reduce the post-harvest browning of litchi.
Abstract
A number of silicon-based inorganic ion exchangers were synthesized under different conditions of preparation. The original and regenerated ion exchange capacities (IECs) were determined. Thermal stability of these materials was investigated in the temperature range of 40–800 °C. The gain/loss of IEC was studied as a function of temperature. These exchangers show a higher IEC and its retention to a considerable extent at elevated temperatures when compared to that of corresponding ion exchangers which do not contain silica. The thermogravimetric curve shows greater percent mass loss in H+ form of the exchanger than in K+ form. Dehydration studies seem to throw some light on the state of water molecules present in various samples. The empirical formula and the tentative structure for stannic arseno silicate have also been proposed.
Thermal stability and crystallization kinetics of Se–Te–Sn alloys using differential scanning calorimetry
DSC study of Se92Te8−x Sn x (x = 0, 1, 2, 3, 4, 5) chalcogenide glasses
Abstract
The present article deals with the differential scanning calorimetric (DSC) study of Se–Te glasses containing Sn. DSC runs are taken at four different heating rates (10, 15, 20 and 25 K min−1). The crystallization data are examined in terms of modified Kissinger, Matusita equations, Mahadevan method and Augis and Bennett approximation for the non-isothermal crystallization. The activation energy for crystallization (E c) is evaluated from the data obtained at different heating rates. Activation energy of glass transition is calculated by Kissinger's relation and Moynihan theory. The glass forming tendency is also calculated for each composition. The glass transition temperature and peak crystallization temperature increases with the increase in Sn % as well as with the heating rate.
Thermal behaviour of aryloxides of titanium(IV) of composition TiCln(OAr)4−n (wheren=0→3 and OAr=OC6But-4, OC6H4OMe-4 and OC6H2-Bu2 t-2,6−Me-4) has been studied by DTA and TG analysis. Multiple decomposition steps have been indicated by thermal weight losses which are both exothermic and endothermic as shown by DTA curves. Based upon the total % loss in weight; during entire decomposition titanium dioxide has been found to be the final residue in each case.
Summary
In this paper we describe a sensitive and reproducible reversed-phase high-performance liquid chromatography (HPLC) method with photodiode-array detection for isolation and quantification of the bioactive hydrophilic constituent 7-(1-O-β-d-galacturonide-4′-(1-O-β-d-glucopyranosyl)-3′,4′,5,7-tetrahydroxyflavone, 1, from the seeds of Cuminum cyminum. Compound 1 was separated isocratically on a C18 preparative column, in high purity, after removal of solvents. The purity and identity of the compound were established by use of LC-mass spectrometry and by spectroscopic techniques (1H and 13C NMR). The purity of 1 was also confirmed by HPTLC.
Nitrogen use efficiency, more specifically physiological nitrogen use efficiency depends primarily on management of N, one of the major essential nutrients. It is required in increased agricultural production and may possibly cause soil toxicity if fed in excess. Rate of N fertilizer application in fertile agricultural field and improved productivity in sterile soils require the improvement of NUE. A field experiment was therefore conducted to evaluate the effect of different N levels (N0, N50, N100 and N200) on rice genotypes. Vegetative plant growth was found to be reduced under N0 while improved at N200 level. Among the genotypes, highest PNUE (34.94) and correspondingly higher yield (7.15 ton ha−1) was observed for Krishna Hamsa. The other traits viz. plant height, no. of productive tillers and LAI exhibited higher values for Krishna Hamsa as well. Hence these can be utilized as physiological markers for the selection of rice genotypes efficient in N use.
Distribution of K027, a hydrophilic, positively charged compound is monitored in the body of pregnant mice using high-performance liquid chromatography (HPLC). Intraperitoneal injection was done on the 18th day of pregnancy; the plasma and brains of the mother mice, placentae and the fetuses’ brains were dissected following 5, 15, 30, 60, and 120 min of treatment. Significant incorporation of K027 was found in the placentae and in fetuses’ brains relative to its levels in the mothers’ plasma and brains. This incorporation warns of a possible adjustment of dose of pyridinium aldoxime antidotes in case of pregnancy. Further studies with different gestational periods and animal models are warranted.
The present paper reports that significant genetic variability was evident in Fe, Zn, β-carotene, and phytic acid (phytate, PA) contents in a set of 39 diverse maize genotypes collected from maize breeding programme of hill agriculture, India. The Fe, Zn, β-carotene, and PA concentrations were found to be in the range 19.31–50.64 mg kg−1, 12.60–37.18 mg kg−1, 0.17–8.27 µg g−1, and 6.59–7.13 g kg−1, respectively. The genotypes V335, V420, V393, V416, V414, V372, and V351 were identified to have higher concentration of β-carotene, Fe, and Zn but lower amount of PA. Possible availability of the minerals Fe and Zn was determined using molar ratio between PA as inhibitor and β-carotene as promoter for their absorption. The micronutrient molar ratio showed that Fe and Zn traits could be dependent of each other. Low R2 value revealed relation between β-carotene and kernel colour. The selected genotypes could be considered as potential sources of favourable genes for further breeding programs to develop micronutrient enriched maize cultivars.
Summary
A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of aripiprazole in human plasma. The analyte and propranolol as internal standard (IS) were extracted from 200 μL of human plasma via liquid-liquid extraction using methyl tert-butyl ether under alkaline conditions. The best chromatographic separation was achieved on an Aquasil C18 (100 × 2.1 mm, 5 μm) column using methanol-deionized water containing 2 mM ammonium trifluoroacetate and 0.02% formic acid (65:35, v/v) as the mobile phase under isocratic conditions. Detection of analyte and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The method was fully validated for its selectivity, interference check, sensitivity, carryover check, linearity, precision and accuracy, reinjection reproducibility, recovery, matrix effect, ion suppression/enhancement, stability, ruggedness, and dilution integrity. The assay was linear over the concentration range of 0.10–100 ng mL−1 for aripiprazole. The intra-batch and inter-batch precision (%CV) was ≤4.8%, while the mean extraction recovery was >96% for aripiprazole across quality control levels. The method was successfully applied to a bioequivalence study of 10 mg aripiprazole orally disintegrating tablet formulation in 27 healthy Indian subjects under fasting and fed condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 260 incurred samples.
