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71.
Smithia conferta Sm. (Leguminasae), is a commonly used plant in Indian traditional medicine. In the current study anti-ulcer activity of its petroleum ether, alcohol and aqueous extracts of leaves were investigated using different animal models. All extracts were also subjected to phytochemical analysis and their toxic potential. Petroleum ether extract was found to contain steroids; alcohol extract revealed the presence of isoflavonoids, alkaloids and carbohydrates; while aqueous extract was found to contain amino acids, carbohydrates and flavonoids. S. conferta aqueous and alcoholic extracts were found to be non-toxic up to 5000 mg/kg dose level while petroleum ether extract was safe only up to a dose of 2000 mg/kg after single dose administration of the extracts.During confirmation of the claimed anti-ulcer activity, treatment with aqueous and alcoholic extracts showed significant reduction in ulcer index, free acidity as well as total acidity in pylorus ligated rats. However, petroleum ether extract showed relatively less profound reduction in all these indices. The anti-ulcer activity observed in aqueous extract treatment group was nearly equivalent to the standard group. 相似文献
72.
The objective of present investigation was to improve the solubility of Eugenol by preparing the inclusion complex of Eugenol with hydroxypropyl-β-cyclodextrin (Hp-β-CD) and characterize the prepared complex by using NMR and differential pulse voltammetry (DPV). Phase solubility curve was plotted using Hp-β-CD in ranging from 0-40 mM of Hp-β-CD and found to be linear. Therefore, inclusion complex was prepared in equimolar ratio of Eugenol and Hp-β-CD by lyophilization method. Fourier transform infrared spectroscopy (FT-IR), (1)H-NMR and DPV were performed for Eugenol, Hp-β-CD and prepared inclusion complex of Eugenol. 2D (two dimensional) NMR was also performed for prepared inclusion complex. The proton of phenol moiety of Eugenol experienced a pronounced chemical shift variation in (1)H-NMR. The positive sign of the variation for proton in (1)H-NMR indicated that the proton was located near to an oxygen atom in the Hp-β-CD cavity and its magnitude showed a strong interaction between -OH proton of Eugenol and Hp-β-CD. 2D NMR confirms the interaction between phenolic group and hydrogen atoms of Hp-β-CD. A well defined anodic peak current corresponding to oxidation of Eugenol in non-encapsulated and Hp-β-CD-Eugenol inclusion complex in phosphate buffer (pH 6.8) was obtained at about 0.35 V and 0.40 V, respectively. The positive shift in oxidation potential indicated the formation of complex via hydrophobic interactions. The oxidant power of Eugenol was retained in complex form as indicated by DPV results. Thus, its oxidation dependent pharmacological property such as antimicrobial activity is not affected after complexation with Hp-β-CD. Thus, (1)H-NMR, 2D-NMR and DPV techniques can be used as valuable tools to determine the mechanism of complexation and state of electrochemical active drug in inclusion complex. 相似文献
73.
The thermal conductivity of disordered silicon-germanium alloys is computed from density-functional perturbation theory and with relaxation times that include both harmonic and anharmonic scattering terms. We show that this approach yields an excellent agreement at all compositions with experimental results and provides clear design rules for the engineering of nanostructured thermoelectrics. For Si(x)Ge(1-x), more than 50% of the heat is carried at room temperature by phonons of mean free path greater than 1 μm, and an addition of as little as 12% Ge is sufficient to reduce the thermal conductivity to the minimum value achievable through alloying. Intriguingly, mass disorder is found to increase the anharmonic scattering of phonons through a modification of their vibration eigenmodes, resulting in an increase of 15% in thermal resistivity. 相似文献
74.
In this paper, the various Optical Burst Switching (OBS) reservation schemes have been examined in order to reduce data loss caused by either channel scheduling or resources. A novel multi-service OBS edge node with synchronized bandwidth reservation mechanism (SRM) has been proposed, which enables high-speed network transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of NS-2 simulation. The results show that the packet delay is kept within the constraint for each traffic flow and the performance metrics such as burst loss rate, throughput and fairness are remarkably improved. 相似文献
75.
Shashaank Gupta Shuvrajyoti Bhattacharjee Dhananjai Pandey Vipul Bansal Suresh K. Bhargava Ju Lin Peng Ashish Garg 《Applied Physics A: Materials Science & Processing》2011,104(1):395-400
We report an unusual behavior observed in (BiFeO3)1−x
–(PbTiO3)
x
(BF–xPT) thin films prepared using a multilayer chemical solution deposition method. Films of different compositions were grown
by depositing several bilayers of BF and PT precursors of varying BF and PT layer thicknesses followed by heat treatment in
air. X-ray diffraction showed that samples of all compositions show mixing of two compounds resulting in a single-phase mixture,
also confirmed by transmission electron microscopy. In contrast to bulk compositions, samples show a monoclinic (MA-type) structure suggesting disappearance of the morphotropic phase boundary (MPB) at x=0.30 as observed in the bulk. This is accompanied by the lack of any enhancement of the remanent polarization at the MPB,
as shown by the ferroelectric measurements. Magnetic measurements showed an increase in the magnetization of the samples with
increasing BF content. Significant magnetization in the samples indicates melting of spin spirals in the BF–xPT films, arising from a random distribution of iron atoms. Absence of Fe2+ ions was corroborated by X-ray photoelectron spectroscopy measurements. The results illustrate that thin film processing
methodology significantly changes the structural evolution, in contrast to predictions from the equilibrium phase diagram,
besides modifying the functional characteristics of the BP-xPT system dramatically. 相似文献
76.
Sally McClean Jennifer Gillespie Lalit Garg Maria Barton Bryan Scotney Ken Kullerton 《European Journal of Operational Research》2014
Stroke disease places a heavy burden on society, incurring long periods of time in hospital and community care, and associated costs. Also stroke is a highly complex disease with diverse outcomes and multiple strategies for therapy and care. Previously a modeling framework has been developed which clusters patients into classes with respect to their length of stay (LOS) in hospital. Phase-type models were then used to describe patient flows for each cluster. Also multiple outcomes, such as discharge to normal residence, nursing home, or death can be permitted. We here add costs to this model and obtain the Moment Generating Function for the total cost of a system consisting of multiple transient phase-type classes with multiple absorbing states. This system represents different classes of patients in different hospital and community services states. Based on stroke patients’ data from the Belfast City Hospital, various scenarios are explored with a focus on comparing the cost of thrombolysis treatment under different regimes. The overall modeling framework characterizes the behavior of stroke patient populations, with a focus on integrated system-wide costing and planning, encompassing hospital and community services. Within this general framework we have developed models which take account of patient heterogeneity and multiple care options. Such complex strategies depend crucially on developing a deep engagement with the health care professionals and underpinning the models with detailed patient-specific data. 相似文献
77.
78.
In the present paper, we solve three boundary value problems related to the temperature field in oil strata — the fractional
extensions of the incomplete lumped formulation and lumped formulation in the linear case and the fractional generalization
of the incomplete lumped formulation in the radial case. By using the Caputo differintegral operator and the Laplace transform,
the solutions are obtained in integral forms where the integrand is expressed in terms of the convolution of some auxiliary
functions of Wright function type. A generalization of the Laplace transform convolution theorem, known as Efros’ theorem
is widely used. 相似文献
79.
80.
P. C. Morais A. C. Oliveira V. K. Garg M. L. Silva E. F. C. Alcântara F. Q. Soares D. Rabelo 《Hyperfine Interactions》2007,177(1-3):51-56
We have used time-differential perturbed angular correlation (PAC) spectroscopy with 181Ta-probes to study the electric field gradient at Zr-sites in synthetic zircon and hafnon between room temperature and 1,200°C. PAC spectra are similar to those obtained from naturally occurring zircons. In particular, a change in slope of the quadrupole coupling vs. temperature is observed in the synthetic zircon at the same temperature as seen in natural zircons from the Mud Tank carbonatite (Australia). The synthetic hafnon data also shows this feature but at somewhat higher temperature. Low-temperature PAC spectra of both synthetic zircon and hafnon have a clearly reduced anisotropy. We believe that the cause for this is a electronic defect, possibly created during the β-decay of the probe parent nucleus. 相似文献