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991.
Demirkiran O Topcu G Hussain J Ahmad VU Choudhary MI 《Magnetic resonance in chemistry : MRC》2011,49(10):673-677
Two new unusual monoterpene glycosides, (Z)-3,6-dimethyl-3-(β-D-O-glucosylmethylene)cyclohept-4-ene-1-one (1) and 3,6-dimethyl-3-(β-D-O-glucosylmethylene)cycloheptanone (2) have been isolated along with five known compounds, 3-hydroxy-4-methoxybenzoic acid, 6,7-dihydroxycoumarin, luteolin, apigenin 5-O-αl-L-rhamnoside, and pinocembrin-7-O-rutinoside from ethyl acetate extract of Euphorbia decipiens. The structures of the isolated compounds were elucidated by extensive 1D- and 2D-NMR, and mass spectroscopic analyses. 相似文献
992.
An isocratic reversed-phase high-performance liquid chromatographic method for the estimation of permethrin in raw materials and pharmaceutical topical preparations has been devised and validated. The chromatographic analysis was performed on a 5 μm particle C-18 Nucleosil (Macherey-Nagel, Germany) column (250 × 4.6 mm). Mobile phase consisted of methanol and 0.025 mM Phosphoric acid (85:15 v/v) at a flow rate of 1.5 mL/min. UV detection was performed at 272 nm and peaks were identified with retention times as compared with standards. The limit of detection was 1.782 μg/mL, while limit of quantitation was 48.0 μg/mL. The calibration was linear in a concentration range of 48.0-5000 μg/mL with correlation coefficient of 0.999978. Regression equation was absorbance =2833.23 × concentration(μg/mL) + 19.1045 with variance of the response variable, S(yx)(2), calculated to be 1.75328 (six degrees of freedom). The method was validated as per ICH guidelines and USP requirements and found advantageous for the routine analysis of the drug in pharmaceutical formulations and in pharmaceutical investigations involving permethrin. 相似文献
993.
Symmetrical 2,5-disubstituted thiophene derivatives containing 1,3,4-oxadiazole moiety bearing different aromatic substitutions
were synthesized by employing convenient and simple synthetic protocols using thiophene-2,5,dicarboxylic acid as a starting
material. The structures of these target molecules were established by their analytical and spectral data. The photophysical
and electrochemical studies were carried out on these compounds and found that they exhibit good fluorescent properties with
high quantum yield. 相似文献
994.
Peerzada R. Hussain Raghuveer S. Meena Mohd A. Dar Ali M. Wani 《Radiation Physics and Chemistry》2011,80(7):817-827
The study is aimed at the optimization of gamma irradiation treatment of sun-dried apricots for quality maintenance and quarantine purposes. Sun-dried apricots pre-treated with potassium meta-bisulphite (KMS) at 2.5% w/v were procured from progressive apricot grower of district Kargil, Ladakh region of Jammu and Kashmir state. The sun-dried apricots were packed in 250 gauge polyethylene packs and gamma irradiated in the dose range 1.0–3.0 kGy. The gamma irradiated fruit including control was stored under ambient (15±2–25±2 °C, RH 70–80%) conditions and periodically evaluated for physico-chemical, sensory and microbial quality parameters. Radiation treatment at dose levels of 2.5 and 3.0 kGy proved significantly (p≤0.05) beneficial in retention of higher levels of β-carotene, ascorbic acid, total sugars and color values without impairing the taste as perceived by the sensory panel analysists. The above optimized doses retained the β-carotene content of sun-dried apricots to the extent of 71.2% and 72.6% compared to 63.9% in control samples after 18 months of storage. Irradiation treatment facilitated the release of residual sulfur dioxide in KMS pre-treated sun-dried apricots significantly (p≤0.05) below the prescribed limit for dried products. During storage, two-fold decrease in sulfur dioxide content was recorded in irradiated samples (3.0 kGy) as compared to 16.9% in control. The above optimized doses besides maintaining the higher overall acceptability of sun-dried apricots resulted in 5 log reductions in microbial load just after irradiation and 1.0 and 1.3 log reductions in yeast and mold and bacterial count after 18 months of ambient storage. 相似文献
995.
Highly diastereoselective 1,2-dichlorination of glycals has been achieved at room temperature conditions in good to excellent yields using a milder, more convenient, less hazardous reagent combination NCS/PPh3 giving only one major product out of four possible diastereomers [either α-gluco (2) or α-manno (4)] depending upon the substituents. The diastereoselectivity is maximum (100% α/β-selectivity as well as cis/trans selectivity) for d-galactal and l-rhamnal derivatives. Detailed studies showed that solvent and substituent effects play a significant role in determining the product distribution. 相似文献
996.
Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-Hz pulse DC discharge technique
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U.Ikhlaq R.Ahmad M.Shafiq S.Saleem M.S.Shah T.Hussain I.A.Khan K.Abbas M.S.Abbas 《中国物理 B》2014,(10):353-360
Molybdenum is nitrided by a 100-Hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry(XRD), scanning electron microscopy(SEM), and atomic force microscopy(AFM) are used for the structural and morphological analysis of the nitrided layers. Vickers’ microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar(1 bar = 105Pa). A considerable increase in surface microhardness(approximately by a factor of 2) is observed for longer duration(10 h) and 2-mbar pressure. Longer duration(10 h) and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen. 相似文献
997.
Mohamed T. Ghoneim Jhonathan P. Rojas Aftab M. Hussain Muhammad M. Hussain 《固体物理学:研究快报》2014,8(2):163-166
We report the inherent increase in capacitance per unit planar area of state‐of‐the art high‐κ integrated metal/insulator/metal capacitors (MIMCAPs) fabricated on flexible silicon fabric with release‐first process. We methodically study and show that our approach to transform bulk silicon (100) into a flexible fabric adds an inherent advantage of enabling higher integration density dynamic random access memory (DRAM) on the same chip area. Our approach is to release an ultra‐thin silicon (100) fabric (25 µm thick) from the bulk silicon wafer, then build MIMCAPs using sputtered aluminium electrodes and successive atomic layer depositions (ALD) without break‐ing the vacuum of a high‐κ aluminium oxide sandwiched between two tantalum nitride layers. This result shows that we can obtain flexible electronics on silicon without sacrificing the high density integration aspects and also utilize the non‐planar geometry associated with fabrication process to obtain a higher integration density compared to bulk silicon integration due to an increased normalized capacitance per unit planar area. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
998.
Active pharmaceutical intermediates (API) in waste waters have adverse effects on aquatic life and environment. The API have high COD value and low BOD3 and hence difficult to treat biologically. In this study, advanced oxidation processes (AOPs) utilizing the H2O2/Fe+2, Fenton reactions were investigated in lab-scale experiments for the degradation of Atenolol containing waste water streams. The experimental results showed that the Fenton process using H2O2/Fe+2 was the most effective treatment process. With Fenton processes, COD reduction of wastewater can be achieved successfully. It is suggested that Fenton processes are viable techniques for the degradation of Atenolol from the waste water stream with relatively low toxic by-products in the effluent which can be easily biodegraded in the activated sludge process. Hence, the Fenton process with H2O2/Fe+2 is considered a suitable pretreatment method to degrade the active pharmaceutical molecules and to improve the biodegradability of waste water. 相似文献
999.
S. Naz S. K. Durrani A. H. Qureshi M. A. Hussain N. Hussain 《Journal of Thermal Analysis and Calorimetry》2013,114(2):719-723
Bismuth titanate (Bi4Ti3O12) was developed by means of titanium oxide (TiO2) suspension in auto-combustion process at 220 °C to get nanosized (20 ± 5 nm) bismuth titanate (Bi4Ti3O12) powder. Complete piezoelectric phase (tetragonal) was obtained after calcination at 700 °C. Dilatometery of compacts was performed to find out sintering temperature. On the basis of shrinkage results, compacts were sintered at 750, 800, and 850 °C for 2 h. After sintering single phase was obtained with orthorhombic structure analyzed by X-ray diffraction and also investigated by Rietveld method. High-resolution scanning electron microscopy revealed that fine plate-like structure which is a characteristic of BIT powder can be obtained at 850 °C. Sintering results indicate that density and average grain size increase with the increasing temperature. A maximum of about 90 % of the theoretical density was achieved for the sintered product at 850 °C. 相似文献
1000.
Umakanta Tripathy Maxime Giguère-Bisson Mohammad Hussain Sangji Marie-Josée Bellemare D. Scott Bohle Elias Georges Paul W. Wiseman 《Analytical and bioanalytical chemistry》2013,405(16):5431-5440
The pigment hemozoin is a natural by-product of the metabolism of hemoglobin by the parasites which cause malaria. Previously, hemozoin was demonstrated to have a very high nonlinear optical response enabling third harmonic generation (THG) imaging. In this study, we present a complete characterization of the nonlinear THG response of natural hemozoin in malaria-infected red blood cells, as well as in pure isostructural synthesized hematin anhydride, in order to determine optimal imaging parameters for detection. Our study demonstrates the wavelength range for optimal pulsed femtosecond laser excitation of THG from hemozoin crystals. In addition, we show the hemozoin crystal detection as a function of crystal size, incident laser power, and the emission response of the hemozoin crystals to different incident laser polarization states. Our systematic measurements of the nonlinear optical response from hemozoin establish detection limits, which are essential for the optimal design of malaria detection technologies that exploit the THG response of hemozoin. Figure
Combined overlay image of THG (bright crystals in blue, one scan per frame) and TP autofluorescence (oval cells in red, average of 15 sequential frame scans) of natural hemozoin crystals and red blood cells (infected with FCR-3 Plasmodium falciparum), respectively, collected at the laser excitation wavelength of 1170 nm with 100 mW average incident power and pixel dwell time of 5 μs 相似文献