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41.
Probes based on anthra[1,2-d]imidazole-6,11-dione were designed and synthesized for selective ion sensing. Each probe acted as strong colorimetric sensors for fluoride and cyanide ions and exhibited intramolecular charge transfer (ICT) band, which showed significant red-shifts after addition of either the F(-) or CN(-) ion. One of the probes (2) showed selective colorimetric sensing for both cyanide and fluoride ions. In organic medium, 2 showed selective color change with fluoride and cyanide, whereas in aqueous organic medium it showed a ratiometric response selectively for cyanide ion. 相似文献
42.
A reversible ‘turn-on’ sensor has been designed for ‘naked-eye’ detection of oxalate at nanomolar concentration (~12.5?nM) at pH 7.4. The sensory system shows a highly specific response towards oxalate among a wide range of antinutrients and biologically relevant anionic species. Mechanistic investigations indicate that oxalate can turn the pink-colored solution colorless by dissociating the preformed metal complex. Additionally, high specificity and good accuracy with recovery values ranging from 93.3 to 105.0% were obtained during oxalate estimation in spiked water and human urine samples, confirming the suitability of the present method in estimating trace-level of oxalate in complex matrices. With these results, quantitative estimations of endogenous oxalate were achieved in more than twenty-five different agricultural crops. Finally, low-cost, portable paper strips were developed for on-site detection of oxalate. 相似文献
43.
Namita Soni J. P. Barthwal A. K. Saxena K. P. Bhargava S. S. Parmar 《Journal of heterocyclic chemistry》1982,19(1):29-32
Fifteen new 3-arylaminomethyl-5-(2-hydroxy-3,5-dibromophenyl)-1,3,4-oxadiazole-2-thiones were synthesized and characterized by their sharp melting points, elemental analyses and ir spectra. These substituted oxadiazolylthiones were evaluated for their enzyme inhibitory activity. All compounds inhibited in vitro monoamine oxidase and succinate dehydrogenase activity of rat brain homogenates. The degree of monoamine oxidase inhibition ranged from 59-93% at a final concentration of 1 × 10?4 M whereas the inhibition of succinate dehydrogenase was 49-100% at a final concentration of 5 × 10?5 M. 相似文献
44.
P. K. DAS A. J. MULLER† G. W. GRIFFIN† I. R. GOULD† C.-H. TUNG† N. J. TURRO† § 《Photochemistry and photobiology》1984,39(3):281-285
Abstract— N, N, N' N' -Tetramethylbenzidine (NTMB) photosensitizes the cis-trans isomerization of stilbene oxiranes (SO) and the extrusion of SO2 from dibenzyl sulfone (DBS). In acetonitrile solution it is found that in the absence of SO or DBS, singlet NTMB undergoes three processes: intersystem crossing to triplet NTMB (φISC = 0.63, k ISC = 6.3 × 107 s-1 ), fluorescence (φf = 0.30, k f = 3 × 107 s-1 ), and formation of a cation by electron ejection (φion = 0.09). Both singlet and triplet sensitization are observed. A charge transfer or reversible electron transfer mechanism is proposed to explain the results. 相似文献
45.
UTTAM K MAZUMDER ANOCK SOMADDER ENAMUL HOQUE YASMEEN HAQUE SUSANTA K DAS H M SEN GUPTA 《Pramana》2016,86(6):1275-1286
Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the 40Ca(6Li, d) 44Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of 44Ti by using the normal optical, Michel and molecular potentials. The extracted spectroscopic factors for the three optical potentials are compared with those of some previous studies of zero-range (ZR) calculations of the 40Ca(6Li, d) 44Ti reaction using the normal optical potential. The χ2 values of all the levels are obtained for the three optical potentials to estimate the quality of the fits. Molecular and Michel potentials have been used for the first time to analyse the four-nucleon transfer reaction and it seems that the molecular potential fits the experimental data more satisfactorily for some of the states than the normal optical and Michel potentials. 相似文献
46.
Shelat KJ Dutta NK Choudhury NR 《Langmuir : the ACS journal of surfaces and colloids》2008,24(10):5464-5473
In a blend, the interfacial interaction between the component phases can be effectively utilized to bring about homogeneous mixing and unique performances. While in conventional blends, preserving the morphology of the melt mixed state is unfeasible because of the strong thermodynamic tendency of the components to phase separate, herein, we report the intermolecular interaction of two hydrogen bonded polymers such as a barrier polymer poly(ethylene-co-vinyl alcohol) (EVOH) with an ionic polymer in their blends, which work symbiotically to achieve the desirable characteristics. We demonstrate the creation of a unique ellipsoid microfibrilliar morphology and melt exfoliation of one polymer in the blends through intermolecular interaction and achieve high oxygen barrier characteristics. Scanning thermal microscopy and scanning electron microscopy investigations confirm the presence of such unique morphology. The interfacial interaction and formation of interphase was evident from the local thermal analysis results combined with photoacoustic Fourier transform infrared spectroscopy (PA-FTIR). PA-FTIR confirms the chemical nature of the interaction, while the differential scanning calorimetry results indicate modification of the EVOH phase by the ionomer. The shift of Tg and broadening of the tan delta curve is evident from dynamic mechanical analysis confirming the interaction of the blend components. The blend B(60) with microfibrillar morphology shows fourfold drop in oxygen permeability indicating the role of interfacial interaction and desired morphology. 相似文献
47.
48.
J. I. S. Khattar D. P. Singh Namita Jindal N. Kaur Y. Singh P. Rahi A. Gulati 《Applied biochemistry and biotechnology》2010,162(5):1327-1338
Limnothrix redekei PUPCCC 116, a filamentous cyanobacterium, has been identified through 16S rRNA gene sequencing. Exopolysaccharides (EPS)
of this organism have been isolated and characterized chemically, and its rheological properties were compared with commercial
xanthan. The organism produced 304 μg EPS/ml culture in 21 days. The rate of EPS production was maximum (313 μg EPS/mg protein/day)
during the initial days of growth, and it decreased to 140 μg EPS/mg protein/day during 18-21 days of growth. Chemical analysis
of EPS revealed the presence of glucose/mannose, ribose, rhamnose, and uronic acid. Fourier transformed infrared spectrum
of EPS further revealed the presence of methyl and carboxyl groups besides C–N groups indicating the presence of peptidyl
moieties. Elemental analysis of EPS showed the presence of 4.97% N. The organism under continuous light produced 102% more
EPS compared to when grown under a light/dark cycle of 14/10 h. The rheological properties of EPS were comparable with commercial
xanthan gum. 相似文献
49.
Yuhua Huang Vinay Girijavallabhan Tze-Ming Chan Mary Senior Namita Bansal Malcolm MacCoss 《Tetrahedron letters》2010,51(21):2800-2802
A general synthetic approach to 4,6-substituted thiazole[4,5-c]pyridines, involving a novel one-pot thiol deprotection-cyclization key step, is described. 相似文献
50.
Upadhyay HC Jaiswal N Tamrakar AK Srivastava AK Gupta N Srivastava SK 《Natural product communications》2012,7(7):899-900
The serial chromatographic separation of chloroform and n-butanol fractions of Ammannia multiflora resulted in the isolation and characterization of 4-hydroxy-alpha-tetralone (1) and 3,3'-(2R,5R)-tetrahydrofuran-2,5-diyldiphenol (ammaniol, 2). Compound 1 was chemically modified into six semi-synthetic acyl and aryl derivatives (1A - 1F). The isolated compounds 1 and 2 along with semi-synthetic derivatives 1A - 1F were evaluated for in vitro antihyperglycemic activity employing 2-deoxyglucose uptake by L-6 rat muscle cell lines. The results indicated that both the isolates, as well as derivatives (1A - 1F), have the property to stimulate glucose uptake. Ammaniol (2) increased glucose uptake significantly (64.8%), while one of the aryl derivatives of 1, 4-O-(3,4,5-trimethoxybenzoyl)-alpha-tetralone (1D), showed potent antihyperglycemic activity and increased glucose uptake by 94.6%, even more than rosiglitazone (88.8%). Further, since 1D possesses better antihyperglycemic activity than rosiglitazone (standard), this might be a new safer antidiabetic drug of herbal origin. 相似文献