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101.
Anti-ulcer activities of xyloccensin-E and xyloccensin-I were investigated in various ulcer models in Sprague-Dawley rats. The effects and the mechanism of action of both compounds for anti-secretory and cytoprotective activities were also studied. Both these active molecules improved the depleted levels of mucin and consequently inhibited the formation of erosions in a pyloric ligated ulcer model. Furthermore, xyloccensin-E and xyloccensin-I inhibited H+K+-ATPase activity in vitro confirming their anti-secretory activity. In conclusion, xyloccensin-E and xyloccensin-I were found to possess anti-ulcerogenic activity which might be due to their anti-secretory activity and subsequent strengthening of the defensive mechanism. 相似文献
102.
Garima Agarwal Vaibhav Kulshrestha Renu Dhunna D. Kabiraj Shikha Verma I. P. Jain 《Applied Physics A: Materials Science & Processing》2010,99(4):879-888
Swift heavy ion (SHI) beam induced irradiation is an established technique for investigating structural modifications in thin films depending
on the S
e sensitivity of material. Intermixing due to 120 MeV Au ion irradiation at different fluences from 1012 to 1014 ions/cm2 has been reported as a function of ion fluence in a-Si/Zr/a-Si thin films on Si substrate. The samples are characterized
before (pristine) and after irradiation using Grazing Incident X-ray Diffraction (GIXRD) and Rutherford Backscattering Spectroscopy
(RBS), which confirm the formation of ZrSi at thin film interface. It is suggested that mixing is mainly due to electronic
energy loss since the energy transferred from high energy ions seems to create a transient molten zone along the ion track.
It is found that the interface mixing increases linearly with the increase in ion fluence. The mixing effect explained in
the framework of Thermal spike model. The irradiation effect on the surface roughness of the system is measured using Atomic
Force Microscopy (AFM) technique. The current conduction mechanism and Schottky barrier height are also calculated by taking
I–V curves across the Metal/Si junction. 相似文献
103.
O. P. Somani T. S. Sunil Kumar B. M. Kukreti B. K. Bhaumik R. A. Gorikhan 《Indian Journal of Physics》2009,83(6):879-885
Gross gamma radiation survey was carried out using Nal(Tl) scintillator based portable gamma ray spectrometer (PGRS) around
areas of Gaonri, Dholera, Pachnota and Meghot in Mahendragarh district, Haryana. Geologically the area forms part of north
Delhi fold belt comprising calc-silicate, quartz biotite schist, impure marble, quartzite and pegmatite rocks. Equivalent
uranium (eU3O8) concentration in ppm was estimated in situ on a regular grid pattern of 500 m (E-W) × 1000 m (N-S) and grab samples were
collected at grid locations for analyzing in the laboratory for estimating the contents of eU3Os Raeq, ThO2 and %K. A comparison with the laboratory analysed grab samples for eU308 data and in situ radiation measurements shows a good match of the two sets of data. The in situ measurements indicate higher
concentration of eU3O8 in Chapra Bibipur in northeastern most corners, Maghot area in central part, Gaonri in western part and Pachnota in southwestern
part of the study area.
As index to uranium favorability, U(Raeq)-Th contour map (prepared using Surfer software with Krieging interpolation method for this grid size) based on the data
on grab samples was generated which show three major clusters of relatively high U-Th ratio. The blocks delineated are enriched
in sodic mineral albite which support albite hosted uranium mineralization potential in metamorphic rocks in Haryana.
相似文献
104.
Vaibhav N. Khose Marina E. John Anita D. Pandey Anil V. Karnik 《Tetrahedron: Asymmetry》2017,28(10):1233-1289
Chiral aspects of benzimidazoles have been over-shadowed for a long time due to the large number of reports on benzimidazoles in the medical field in numerous categories of therapeutic agents. The vigorous research activity in chiral applications of benzimidazole derivatives started after bifunctional benzimidazoles made their appearance especially in the last 2–3 decades. Thus, chiral benzimidazoles form a comparatively young branch of chiral chemistry. The presence of pyridine and pyrrole type of nitrogens along with the fused benzene ring confer on this class of molecules, special properties including useful nucleophilicity, hydrogen bonding ability and a rigid backbone, all of which play decisive roles in proven chiral applications. The present review aims to cover the synthetic routes to access chiral benzimidazoles and their applications in a plethora of chiral fields including enantioselective organocatalysis, metal-based catalysis, asymmetric transformations involving benzimidazole-N-heterocyclic carbenes, kinetic resolution, benzimidazole-based macrocyclic hosts in chiral supramolecular chemistry and other miscellaneous chiral applications. 相似文献
105.
106.
107.
Vaibhav P. Mehta Jos‐Antonio García‐Lpez Michael F. Greaney 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(6):1555-1559
Three orthogonal cascade C H functionalization processes are described, based on ruthenium‐catalyzed C H alkenylation. 1‐Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p‐cymene)Cl2}2] and stoichiometric Cu(OAc)2. Each transformation uses C H functionalization methods to form C C bonds sequentially, with the indeno furanone synthesis featuring a C O bond formation as the terminating step. This work demonstrates the power of ruthenium‐catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple C H functionalization steps taking place in a single operation to access novel carbocyclic structures. 相似文献
108.
Fekadu Mosisa Wako Ali Shemshedin Reshad Vaibhav V. Goud 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2157-2165
Thermal cracking of waste cooking oil (WCO) for production of liquid fuel has gained special interest due to the growing demand of renewable fuel, depleting fossil fuel reserves and environmental issues. In the present work, thermal cracking of WCO to produce liquid hydrocarbon fuels without any preprocessing has been studied. Moreover, non-isothermal kinetics of WCO using thermogravimetric analysis (TGA) has been studied under an inert atmosphere at various heating rates. According to TGA result, active thermal decomposition of WCO was found to be between 318 and 500 °C. Furthermore, the temperature at which the maximum mass loss rate attained was shifted to higher values as the heating rates increased from 10 to 50 °C min?1 and the values were found to be approximately similar to that of R 50. Besides, model-free iso-conversion kinetic methods such as Friedman (FM), Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) were used to determine the activation energies of WCO degradation. The average activation energy for the thermal degradation of WCO was found to be 243.7, 211.23 and 222 kJ mol?1 for FM, KAS and FWO kinetic methods, respectively. Additionally, the cracking of WCO was studied in a semi-batch reactor under an inert atmosphere and the influences of cracking temperature, time and heating rates on product distribution were investigated. From the reaction, an optimum yield of 72 mass% was obtained at a temperature of 475 °C, time of 180 min and a heating rate of 10 °C min?1. The physicochemical properties studied were in accordance with ASTM standards. 相似文献
109.
Priya Fuke Vaibhav V. Gujar Anshuman A. Khardenavis 《Applied biochemistry and biotechnology》2018,184(3):970-986
Stabilization and utilization of poultry waste demand efficient biodegradation either by mixture of enzymes or by microbial system that can produce different types of protein-hydrolyzing enzymes. For utilization of this keratinous biomass, in the present study, genome was sequenced and annotated for a bacterium having multiple enzymatic options for hydrolysis of different soluble and insoluble protein fractions of poultry waste. Among the soluble protein substrates, optimum production of enzyme and soluble protein was observed in case of casein, whereas among the insoluble protein substrates, maximum production of enzyme was achieved when broken nails were used. Conditions for enhanced enzyme activity with concurrent degradation of keratin-rich poultry feather waste to protein-rich hydrolysate were optimized for different growth parameters. The bacterium grew well and highest protease production occurred in 144 h at mesophilic temperature (30 °C) and alkaline condition (pH 8–10) with enzyme activities of 134 and 168 U/mL, respectively. 相似文献
110.
Vaibhav S. Khire April M. Kloxin Charles L. Couch Kristi S. Anseth Christopher N. Bowman 《Journal of polymer science. Part A, Polymer chemistry》2008,46(20):6896-6906
This study investigates the formation of linear polymer grafts using thiol‐acrylate conjugate addition reactions on nanoparticle surfaces. Silica nanoparticles were first modified with an amine functionality, followed by the attachment of a photocleavable acrylate. Dithiol‐diacrylate films were attached to the particles through the surface acrylate groups at various stoichiometric ratios of thiol to acrylate by conducting amine‐catalyzed conjugate addition polymerizations. The particles were then exposed to UV light to release the grafted polymer by photocleavage. The cleaved, grafted polymers were analyzed using infrared spectroscopy and gel permeation chromatography and compared to polymers formed in the bulk, which remained unattached to the particles. The measured number and weight average molecular weights were similar for both polymer types within experimental error and increased from 2000 to 5000 g/mol and 4000 to 10,000 g/mol, respectively, as the ratio of limiting to excess functionality increased from 0.8 to 1. Both number and weight average molecular weights followed the trend of step growth polymers with the highest molecular weight achieved for stoichiometric monomeric mixtures. Surface coverage of the nanoparticles was estimated using the molecular weight and thermogravimetric data and was found to be uniform (~0.15 chains/nm2) irrespective of the stoichiometry of the reacting monomers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6896–6906, 2008 相似文献