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51.
A simple and rapid LC method was developed and validated for simultaneous estimation of nebivolol and amlodipine in a bi-layer tablet formulation. Efficient chromatographic separation was achieved on (USP L10) Hypersil BDS cyano, 5 μm, 250 mm × 4.6 mm column with simple mobile phase composition delivered in isocratic mode. The method had requisite accuracy, selectivity, sensitivity, robustness and precision to assay nebivolol and amlodipine in pharmaceutical dosage form. Degradation products resulting from the stress studies did not interfere with the detection of nebivolol and amlodipine, these peaks remained pure and thus proved to be stability indicating. The mass balance of the stressed sample was in the range 99.0–100.2% for amlodipine and 99.3–100.3% for nebivolol. 相似文献
52.
Capillary electrophoresis affords a simple, automated approach for the measurement of pKa values in the range 2-11 at a throughput of less than 1 h per sample per instrument. Agreement with literature values is usually within 0.20 log units with a precision better than 0.07 log units. The attractive features of capillary electrophoresis for pKa measurements are: (1) conventional instrumentation with a high level of automation are suitable for all measurements; (2) because it is a separation method samples need not be of high purity; (3) samples of low water solubility with suitable chromophores are easily handled (detection limits in the microM range); (4) sample consumption per measurement is in the microgram range; and (5) since only mobilities are measured, exact knowledge of concentrations is not needed. The general approach can be extended to pKa measurements in aqueous-organic solvent mixtures and non-aqueous solvents with suitable calibration. The widespread use of absorbance detection in capillary electrophoresis means that the sample must have a suitable chromophore for detection. The main source of controllable error is the accuracy of buffer standardization and their stability in use, and uncontrollable error, the retentive interactions of the sample with the column wall. The latter seems to be a rare problem in practice for typical operating conditions. 相似文献
53.
Sneha Samal Martin Stuchlík Iva Petrikova 《Journal of Thermal Analysis and Calorimetry》2018,131(2):1035-1040
Natural fabric such as flax and jute was considered in biaxial plain reinforcement in matrix of acrylic resin, and the composite is prepared in hand layup techniques. Fabric mass fraction of 7% was used in the matrix of composite. The samples were treated at r.t and 60 °C for the final fabrication. Scanning electron microscopy was carried out to support the microstructure effect of composite in terms of thermal change. Thermogravimetric and differential thermogravimetric analysis and residual compositional analysis with FTIR were carried out for the composite and matrix samples. The mechanical and viscoelastic properties, as well as the influence of frequency and fibers types, were evaluated, in flexural mode, by means of dynamical mechanical analysis. Glass transition (T g) and initial decomposition (T i) temperatures increase with incorporation of fibers into the matrix. While T i of flax and jute composite was similar, T g in case of flax improves than jute fabric-reinforced composite. This type of composites can be used in the automotive sector, in exterior and exterior components. 相似文献
54.
Ibrahim Ahmed Shaikh Uday M. Muddapur Zabin K. Bagewadi Sneha Chiniwal Mohammed M. Ghoneim Mater H. Mahnashi Fahad Alsaikhan Deepak Yaraguppi Francois N. Niyonzima Sunil S. More Basheerahmed Abdulaziz Mannasaheb Amer Al Ali Abdulaziz Asiri Aejaz Abdullatif Khan S. M. Shakeel Iqubal 《Molecules (Basel, Switzerland)》2022,27(9)
The applications of bioactive compounds from medicinal plants as therapeutic drugs are largely increasing. The present study selected the bioactive compounds from Acacia concinna (A. concinna) and Citrus limon (C. limon) to assess their phytochemicals, proteins, and biological activity. The plant material was collected, and extraction performed as per the standard procedure. Qualitative analysis was undertaken, and identification of functional organic groups was performed by FTIR and HPLC. Antibacterial, anticancer, antioxidant, antihyperglycemic, antihyperlipidemic, and inhibition kinetics studies for enzymes were performed to assess the different biological activities. Flavonoids and phenols were present in a significant amount in both the selected plants. A. concinna showed significant antimicrobial activity against Z. mobilis, E. coli, and S. aureus, with minimum inhibition zones (MIZ) of 24, 22, and 20 mm, respectively. C. limon strongly inhibited all the tested pathogenic bacteria with maximum and minimum MIZ of 32 and 17 mm. A. concinna silver nanoparticles also exhibited potent antimicrobial activity. Both extracts showed substantial antioxidant, antihyperlipidemic, antidiabetic, anticancer (MCF-7), and anti-urease (antiulcer) properties. To conclude, these plants can be used to treat hyperlipidemia, diabetes, cancer, and gastrointestinal ulcers. They can also serve as antimicrobial and antioxidant agents. Thus, the studied plants must be exploited cost-effectively to generate therapeutic drugs for various diseases. 相似文献
55.
Direct Observation of Molecular‐Level Template Action Leading to Self‐Assembly of a Porous Framework
Sneha R. Bajpe Christine E. A. Kirschhock Prof. Alexander Aerts Dr. Eric Breynaert Dr. Gregory Absillis Tatjana N. Parac‐Vogt Prof. Lars Giebeler Dr. Johan A. Martens Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(13):3926-3932
The molecular steps involved in the self‐assembly of Cu3(BTC)2 (BTC=1,3,5‐benzenetricarboxylic acid) metal–organic frameworks that enclose Keggin‐type H3PW12O40 heteropolyacid molecules were unraveled by using solution 17O, 31P, and 183W NMR spectroscopy, small‐angle X‐ray scattering, near‐IR spectroscopy, and dynamic light scattering. In aqueous solution, complexation of Cu2+ ions with Keggin‐type heteropolyacids was observed. Cu2+ ions are arranged around the Keggin structure so that linking through benzenetricarboxylate groups results in the formation of the Cu3(BTC)2 MOF structure HKUST‐1. This is a unique instance in which a templating mechanism that relies on specific molecular‐level matching and leads to explicit nanoscale building units can be observed in situ during formation of the synthetic nanoporous material. 相似文献
56.
Gunjan Pandey Tasneem Fatma Sneha Sudha Komath 《Photochemistry and photobiology》2009,85(5):1126-1133
In a recent study, we found that jacalin, a T-antigen specific lectin could interact with phycocyanin (PC) in a carbohydrate-independent manner. We show here that concanavalin A and peanut agglutinin too can interact with PC, although the nature of the interaction is distinctly different from that for jacalin. The legume lectins bind PC weaker in the presence of their specific carbohydrate ligands. Like jacalin, the legume lectins too interact with PC via two distinct sites. Higher ionic strengths resulted in a weakening of the interaction at site 1 and did not affect the interaction at site 2 , clearly indicating that the interactions involve charged residues at the former and hydrophobic interactions at the latter site. The implications for the use of these lectin–PC complexes in photodynamic therapy and other clinical applications are discussed. 相似文献
57.
X-ray photoelectron spectroscopy was used to study the effect of atomic oxygen on Ru(0 0 0 1), and the effect of dissociated ammonia on RuO2/Ru(0 0 0 1), in UHV conditions at ambient temperature. The Ru(0 0 0 1) surface was exposed, at ambient temperature, to a mixed flux of atomic and molecular oxygen generated by dissociation of O2 in a thermal catalytic cracker, with 45% dissociation efficiency. The detailed study of the XPS spectra shows the formation of a disordered multilayer oxide (RuO2). No formation of higher oxides of Ru was observed. The formation of RuO2 proceeded without saturation for total oxygen exposures of up to 105 Langmuir, at which point an average oxide thickness of 68 Å was observed. RuO2 formed by the reaction with atomic oxygen was exposed to a flux of NHx (x = 1, 2) + H generated by the cracker. The reduction of RuO2 to Ru metal was observed by XPS. An exposure of 3.6 × 102 L of NHx + H, resulted in the observation of adsorbed H2O and OH, but no evidence of lattice oxide. The chemisorbed species were removed by additional NHx + H exposure. No nitrogen adsorption was observed. 相似文献
58.
Chandan L. Gupta Tapas C. Nag Kumar Abhiram Jha Poorti Kathpalia Meenakshi Maurya Pankaj Kumar Sneha Gupta Tara S. Roy 《Photochemistry and photobiology》2020,96(5):1061-1073
Light insult causes photoreceptor death. Few studies reported that continuous exposure to light affects horizontal, Müller and ganglion cells. We aimed to see the effect of constant light exposure on bipolar and amacrine cells. Adult Sprague-Dawley rats were exposed to 300 or 3000 lux for 7 days in 12-h light: 12-h dark cycles (12L:12D). The latter group was then exposed to 24L:0D for 48 h to induce significant damage. The same animals were reverted to 300 lux and reared for 15 days in 12L:12D cycles. They were sacrificed on different days to find the degree of retinal recovery, if any, from light injury. Besides photoreceptor death, continuous light for 48 h resulted in downregulation of parvalbumin in amacrine cells and recoverin in cone bipolar cells (CBC). Rod bipolar cells (RBC) maintained an unaltered pattern of PKC-α expression. Upon reversal, there were increased expressions of parvalbumin in amacrine cells and recoverin in CBC, while RBC showed an increasing trend of PKC-α expression. The data show that damage in bipolar and amacrine cells after exposure to intense, continuous light can be ameliorated upon reversal to normal LD cycles to which the animals were initially acclimated to. 相似文献
59.
Sreekumar Sneha Xavier Soumya Govindan Avudaiappan Thampikannu Raihamol Erattammottil Vellayan Kannan González Beatriz 《Research on Chemical Intermediates》2020,46(10):4529-4542
An active Pd catalyst was prepared by the modification of montmorillonite clay. The catalyst was found to be effective for the synthesis of ethylenedioxy thiophene-based π-conjugated molecules. The reaction proceeded through clay-supported Pd-catalysed direct C–H bond activation (arylation) mechanism. Preparation, characterization and application of the catalysts are reported. The products were analysed with LCMS, and comparison with reported spectral data (FT-IR, 1H NMR). Reusability of clay-supported palladium catalyst towards direct arylation reaction was tested for three reaction cycles without a significant loss of catalytic activity.
相似文献60.
Development of injectable high molecular weight hyaluronic acid hydrogels for cartilage regeneration
Shraddha Mondal Neena Haridas S. Sneha Letha V. Vijith G. Rajmohan 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(8):507-514
The study focuses on developing hyaluronic acid (1200 kilo Dalton) hydrogels for cartilage regeneration. In spite of being highly biocompatible; a large amount of water absorption and easily degrading nature restricts the use of hyaluronic acid in the field of tissue regeneration. This can be rectified by crosslinking hyaluronic acid with a crosslinking agent such as divinyl sulfone; which results in a biocompatible hydrogel with superior rheological properties. Different amounts of divinyl sulfone have been used for crosslinking hyaluronic acid to get three types of hydrogels with differing properties. Swelling studies, rheology analysis, enzymatic degradation and scanning electron microscopic analysis were conducted on all the different types of hydrogels prepared. Viscoelastic properties of the hydrogel were analyzed so that a hydrogel with better elastic property and stability is obtained. Scanning electron microscopy was used to study the morphology of the HA hydrogels. The cytotoxicity testing was conducted to prove the non-toxic nature of the hydrogels and cell culture studies using adipose mesenchymal stem cells showed better adhesion and proliferation properties in all the three hydrogels. Thus hyaluronic acid hydrogel makes a promising material for cartilage regeneration. 相似文献