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101.
Pulaganti Vijaya Prasad Medi Shanker Avudoddi Venkanna Marapala Kumara Swamy K. Gopichand 《合成通讯》2018,48(9):1040-1044
A facile and efficient synthesis of pyrrole and pyrrole-fused heterocyclic compounds has been demonstrated. The current protocol involves the in situ generation of azomethine ylides which undergoes intermolecular cycloaddition reaction and subsequent treatment with DDQ provides the pyrrole and fused heterocyclic compounds in good yields. 相似文献
102.
Uma Shanker Vidhisha Jassal Manviri Rani Balbir Singh Kaith 《International journal of environmental analytical chemistry》2016,96(9):801-835
Current advancements in green synthesis of materials especially nanoparticles have led to conservation of natural and non-renewable resources along with reduction in environmental pollution. Development of cost-effective, simple and eco-friendly routes for the synthesis of nanoparticles is very important. All over the world, a wide variety of biogenic sources have been put to trial as a source of green agents to facilitate synthesis process. In addition to this, environmentally benign solvents are also being used these days in order to promote green synthesis. In this review, an attempt has been made to familiarise the readers with the different green routes for the synthesis of nanoparticles. 相似文献
103.
104.
Vadde Ravinder Sigala Ashok M. Satish Varma C. V. Raghunath Babu Kanne Shanker Gubba Balaswamy 《Chromatographia》2009,70(1-2):229-232
A rapid isocratic chiral LC method has been developed for the separation of (S)-cinacalcet from (R)-cinacalcet. Good resolution with R S > 3 was obtained using a Chiralpak-IA column (250 × 4.6 mm, particle size 5 μm) and n-hexane, ethanol and trifluoroacetic acid as the mobile phase (95:5:0.1, v/v) at ambient temperature. Flow rate was kept at 1.0 mL min–1 and elution was monitored by UV detection at 223 nm. This method was further used to determine the presence of (S)-cinacalcet in enantiopure pharmaceutical formulations containing (R)-cinacalcet. This method allowed for the detection and quantitation of (S)-cinacalcet of levels at 0.04 and 0.16 μg mL–1, respectively. The method was validated following ICH guidelines. 相似文献
105.
Bhupendra Singh Rathore Mulayam Singh Gaur Kripa Shanker Singh 《Journal of Thermal Analysis and Calorimetry》2012,107(2):675-680
The thermally stimulated charge relaxation properties of polycarbonate (PC) filled with SiO2 nanofiller were studied by means of thermally stimulated discharge current (TSDC). The nanocomposite samples were further
characterized by UV–vis spectroscopy, scanning electron microscopy, energy dispersive X-ray spectra, and differential scanning
calorimetry (DSC) techniques to investigate the dispersion of nanofillers in polymer matrix and glass transition temperature.
All pristine and nanocomposites samples of thickness about 25 μm were prepared using solution mixing method. The suitable
weight percentage of SiO2 nanofillers has been chosen to prevent the nonuniform dispersion. TSDC measurement of PC (Pristine) and PC+ (7% SiO2) shows the single peak, while TSDC characteristic of other nanocomposites are showing two peaks. The higher temperature TSDC
peak of pristine and nanocomposites samples is originated due to the charge relaxation from shallower and deeper trapping
sites, however, low temperature peak is caused by dipolar relaxation of charge carriers. Since the position of higher temperature
TSDC peak is generally an analysis of glass transition temperature of polymer/polymer nanocomposites. The authors have observed
that the temperature of this peak is almost same as the T
g measured by DSC with 0 to ±5% variation. This article presents the deeper understanding of charge relaxation mechanism caused
by SiO2 nanofillers in polycarbonate. 相似文献
106.
We present new experimental data on thick target bremsstrahlung spectra generated from the interaction of energetic electrons
with bulk matter. The ‘photon yields’ in terms of double differential cross-sections (DDCS) are measured for pure elements
of thick targets: Ti (Z = 22), Ag (Z = 47), W (Z = 74) and Pt (Z = 78) under the impact of 10 keV electrons. Comparison of DDCS obtained from the experimental data is made with those predicted
by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the experimental data and the MC calculations
is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung
photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty
of about 10% and they are compared with MC calculations. A satisfactory agreement is found between the experiment and the
calculations within some normalizing factors. The variations of DDCS as a function of Z and of photon energy are also studied which show that the DDCS vary closely with Z; however, some deviations are observed for ‘tip’ photons emitted from high Z targets. 相似文献
107.
108.
Chitosan acetate-ammonium nitrate (NH4NO3) films have been prepared by the solution-cast technique. Fourier transform infrared spectroscopy (FTIR) showed that complexation has occurred. FTIR exhibited shifts in amine and carbonyl bands from 1553 to 1520 cm−1 and 1636 to 1617 cm−1. A new peak was also observed at 1746 cm−1. XRD shows that all complexes are amorphous. The highest conductivity at room temperature is 2.53×10−5 S cm−1 for the film containing 45 wt% NH4NO3. The conductivity of the samples is dependent on the number of mobile ions and mobility. 相似文献
109.
Mohd Anis Ganaie Agbaje Lateef Uma Shanker Gupta 《Applied biochemistry and biotechnology》2014,172(4):2143-2159
Fructooligosaccharides are influential prebiotics that affect various physiological functions in such a way that they promote positive impact to health. They occur naturally in many fruits and vegetables in trace amounts. However, they are mainly produced commercially by the reaction of microbial enzymes with di- or polysaccharides, such as sucrose or inulin as a substrate. For maximum production of fructooligosaccharides on an industrial level, development of more enzymes with high activity and stability is required. This has attracted the attention of biotechnologists and microbiologists worldwide. This study aims to discuss the new trends in the production of fructooligosaccharide and its effect on numerous health qualities through which it creates great demand in the sugar market. 相似文献
110.
Channabasaveshwar V. Yelamaggad Rashmi Prabhu Govindaswamy Shanker 《Liquid crystals》2013,40(3):247-255
The synthesis, molecular structural characterisation and mesomorphic behaviour of lanthanidomesogens with the formula [LnL(LH)2 ][X]2 are reported. These mesogens were derived from ligands (LH- n ) formed by covalently linking the pro-mesogenic cholesterol segment with the N-(n-decyl)salicylaldimine core through either an even-parity (4-oxybutanoyloxy/6-oxyhexanoyloxy/8-oxyoctanoyloxy) or an odd-parity (5-oxypentano-yloxy) spacer. These ligands were designed based on the recently conceived concept of decoupling the anisometric segment from the metal-coordinating site by a flexible spacer to account for the stabilisation of nematic and/or smectic phases at lower temperatures. The even parity spacer ligands are polymesomorphic whereas the odd parity analogue exhibits only the chiral nematic phase. In contrast, the complexes display solely the smectic A phase indicating that the variation in the nature of lanthanide has no influence on the general phase behaviour of the complexes. The clearing temperatures of both the ligands and the complexes display an odd-even effect; the even members show relatively higher transition temperatures. 相似文献