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© 1996 American Institute of Physics One of the authors (P.S.D.) would like to thank CSIR (India) for the award of a senior research fellowship. U.P. gratefully acknowledges MEC (Spain) for the postdoctoral fellowship. This work was partially supported by the Universidad Autonoma de Madrid, Spain, through a visiting scientist fellowship and by DGICYT Project Nos. PB93-1256 and ESP95-014, Passivation of point and extended defects in GaSb has been observed as a result of hydrogenated amorphous silicon (a-Si:H) treatment by the glow discharge technique. Cathodoluminescence (CL) images recorded at various depths in the samples clearly show passivation of defects on the surface as well as in the bulk region. The passivation of various recombination centers in the bulk is attributed to the formation of hydrogen-impurity complexes by diffusion of hydrogen ions from the plasma a-Si:H acts as a protective cap layer and prevents surface degradation which is usually encountered by bare exposure to hydrogen plasma. An enhancement in luminescence intensity up to 20 times is seen due to the passivation of nonradiative recombination centers. The passivation efficiency is found to improve with an increase in a-Si:H deposition temperature. The relative passivation efficiency of donors and acceptors by hydrogen in undoped and Te-compensated p-GaSb has been evaluated by CL and by the temperature dependence of photoluminescence intensities. Most notably, effective passivation of minority dopants in tellurium compensated p-GaSb is evidenced for the first time., Universidad Autonoma de Madrid, Spain, DGICYT, Depto. de Física de Materiales, Fac. de Ciencias Físicas, TRUE, pub

Mangiferin is the one of the major active constituents in the tubers of the Salacia species, which is one of the valuable species in Ayurveda with antidiabetic, antihypertensive, hepatoprotective, anticaries and anticancer potentials. A simple and rapid liquid chromatography coupled mass spectrometry analysis was developed for the quantification of Mangiferin in two species of Salacia and also in polyherbal formulation. This method allowed the direct coupling of an electron spray mass selective detector for the LC system with photo diode array detector, Phenomenex C18 column, acetonitrile and aqueous formic acid (0.5%) as mobile phase. Under these conditions, Mangiferin was well separated from the mixture of components present in the extract and detected with mass spectrometry (mass selective detector).Liquid chromatography coupled with electron spray mass was used in positive ion mode and detected at m/z 423(M+1)+. The proposed method is more accurate and sensitive can be used for the routine quantification of the Mangiferin in the herbal extracts as well as polyherbal formulations.

Mangiferin is the one of the major active constituents in the tubers of the Salacia species, which is one of the valuable species in Ayurveda with antidiabetic, antihypertensive, hepatoprotective, anticaries and anticancer potentials. A simple and rapid liquid chromatography coupled mass spectrometry analysis was developed for the quantification of Mangiferin in two species of Salacia and also in polyherbal formulation. This method allowed the direct coupling of an electron spray mass selective detector for the LC system with photo diode array detector, Phenomenex C18 column, acetonitrile and aqueous formic acid (0.5%) as mobile phase. Under these conditions, Mangiferin was well separated from the mixture of components present in the extract and detected with mass spectrometry (mass selective detector).Liquid chromatography coupled with electron spray mass was used in positive ion mode and detected at m/z 423(M+1)+. The proposed method is more accurate and sensitive can be used for the routine quantification of the Mangiferin in the herbal extracts as well as polyherbal formulations.

Mangiferin is the one of the major active constituents in the tubers of the Salacia species, which is one of the valuable species in Ayurveda with antidiabetic, antihypertensive, hepatoprotective, anticaries and anticancer potentials. A simple and rapid liquid chromatography coupled mass spectrometry analysis was developed for the quantification of Mangiferin in two species of Salacia and also in polyherbal formulation. This method allowed the direct coupling of an electron spray mass selective detector for the LC system with photo diode array detector, Phenomenex C18 column, acetonitrile and aqueous formic acid (0.5%) as mobile phase. Under these conditions, Mangiferin was well separated from the mixture of components present in the extract and detected with mass spectrometry (mass selective detector).Liquid chromatography coupled with electron spray mass was used in positive ion mode and detected at m/z 423(M+1)+. The proposed method is more accurate and sensitive can be used for the routine quantification of the Mangiferin in the herbal extracts as well as polyherbal formulations.

Mangiferin is the one of the major active constituents in the tubers of the Salacia species, which is one of the valuable species in Ayurveda with antidiabetic, antihypertensive, hepatoprotective, anticaries and anticancer potentials. A simple and rapid liquid chromatography coupled mass spectrometry analysis was developed for the quantification of Mangiferin in two species of Salacia and also in polyherbal formulation. This method allowed the direct coupling of an electron spray mass selective detector for the LC system with photo diode array detector, Phenomenex C18 column, acetonitrile and aqueous formic acid (0.5%) as mobile phase. Under these conditions, Mangiferin was well separated from the mixture of components present in the extract and detected with mass spectrometry (mass selective detector).Liquid chromatography coupled with electron spray mass was used in positive ion mode and detected at m/z 423(M+1)+. The proposed method is more accurate and sensitive can be used for the routine quantification of the Mangiferin in the herbal extracts as well as polyherbal formulations.

Cellulose has been the extracted from rice husk by chemical treatment with aqueous solution of sodium hydroxide. The physical properties of derived cellulose (water uptake and swelling behavior) has been investigated with view of different applications. The morphology and chemical structure were investigated by Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Thermogravimetry (TG) techniques. The results revealed the formation of homogeneous porous (micro size) membrane. Further, the UV-vis spectra of cellulose in different pH shows its responsiveness towards hydronium ion, which is suitable for drug delivery. Further, obtained cellulose was used for drug delivery under optimized pH.

Cellulose has been the extracted from rice husk by chemical treatment with aqueous solution of sodium hydroxide. The physical properties of derived cellulose (water uptake and swelling behavior) has been investigated with view of different applications. The morphology and chemical structure were investigated by Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Thermogravimetry (TG) techniques. The results revealed the formation of homogeneous porous (micro size) membrane. Further, the UV-vis spectra of cellulose in different pH shows its responsiveness towards hydronium ion, which is suitable for drug delivery. Further, obtained cellulose was used for drug delivery under optimized pH.

Thin films of titanium dioxide in anatase form have been prepared using isobutyl titanate as precursor. The resulting TiO2 was coated on an U-shaped pyrex glass rod to sense the humidity of a controlled humid environment using optical fiber approach. The humidity sensing characteristics and the sensing mechanism have been investigated by measuring the output power of the sensor at different humidity. The developed humidity sensor was responded in the humidity ranging from 10 to 95% of relative humidity and exhibited the sensitivity of 0.78, response time 36s and recovery time 73s.

Objective: To study the beneficial role of Seabuckthorn (Hippophae rhamnoides) in the maintenance of cardiovascular homeostasis following cold stress. Materials and Methods: The effect of the alcoholic extract of Seabuckthorn in the daily oral dose of 500 mg was studied on various electrophysiological and neurochemical parameters following cold stress among the positive cold stress responders (human subjects) continuously for 3 months. Results: The average differences in cardiovascular responses like systolic and diastolic blood pressure, and pulse rate that were found to be raised following cold pressor test, minimized following three months oral administration of Seabuckthorn. Further, the psychophysiological parameters like occipito frontalis EMG and galvanic skin resistance also regulated under drug treatment. The serotonin and plasma cortisol levels were also modified following oral administration of Seabuckthorn. Conclusion: Seabuckthorn exhibited beneficial effects to reduce the cardiovascular reactivity following cold stress and thus it enhances the stress tolerance capacity as well as better adaptation towards stress.