6,565 research outputs found

    ETHNOMEDICINAL, PHYTOCHEMICAL AND PHARMACOLOGICAL ASPECTS OF FLACOURTIA JANGOMAS: A REVIEW

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    Flacourtia jangomas (Lour.) Raeusch., a small tree of Willow family distributed throughout tropical regions of East Africa and Asia is well-known for its culinary and medicinal uses. The plant has received increasing interest due to its limonoid constituents. Phytochemical studies have led to the isolation and characterization of an array of bioactive compounds and pharmacological investigations have validated the traditional uses of the species as well as discovered some new bioefficacies. The aim of the review is to present an updated and comprehensive overview of traditional uses, ethnomedicinal significance, phytochemical and pharmacological aspects of F. jangomas to highlight its ethnopharmacological use and to explore its therapeutic potentials thereby providing a basis for future research. Relevant information and literature on F. jangomas from electronic databases such as Academic Journals, Google, Google Scholar, PubMed, Web of Science, and Science Direct were consulted and analyzed. Available literatures evidently demonstrate that F. jangomas possess a wide spectrum of pharmacological activities that could be explained by the presence of varied range of chemical constituents. Phytochemical and pharmacological investigations showed that extracts of different parts and major active components of F. jangomas had antimicrobial, analgesic, antidiabetic, antidiarrheal, antioxidant and cytotoxic activities. This emphasizes the need for further investigation to explore more bioactive chemical constituents and new bioefficacies of the plant and to establish a credible relationship between molecular structure and activity of compounds

    ANTIFUNGAL ACTIVITY OF NATURAL COLOURANT FROM MELIA COMPOSITA BARK AND ITS APPLICATION IN FUNCTIONAL TEXTILE FINISHING

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    Objective: The present study was aimed to evaluate the antifungal efficacy of natural dye obtained from Melia composita bark and its impact on the antimicrobial finishing of different types of textile fabrics.Methods: Antifungal activity of M. composita bark dye was assessed against standard strains of five fungi namely Aspergillus flavus, A. niger, A. parasiticus, Fusarium moniliforme and Penicillium canescens using agar-well diffusion method. The minimum inhibitory concentration (MIC) was determined by broth dilution method. The antifungal potency of dyed fabrics (silk, wool, and cotton) against the five test fungi was quantitatively evaluated by reported method.Results: Different treatment doses of natural dye exhibited a varying degree of antifungal activity against the five test fungi. The treatment dose of 100 mg/ml and above were considerably active. Growth inhibition impact of natural dye at 250 mg/ml dose was almost at par with positive control. Maximum growth inhibition in all the five test fungi was evident with 500 mg/ml dose followed by 250 and 100 mg/ml. MIC of the natural dye against test fungi were found in the range of 20.50-23.00 mg/ml. Dyed fabrics of silk, wool, and cotton also showed remarkable antifungal efficacy against all the test fungi. The highest growth reduction was observed in A. parasiticus whereas lowest in P. canescens with the three types of dyed fabrics. Dyed wool fabrics exhibited the maximum growth reduction followed by silk and cotton fabrics.Conclusion: The study revealed the remarkable antifungal activity of natural dye from barks of M. composita; therefore, the plant can be considered as a good source of natural dye with functional properties and can be used in commercial dyeing and protective finishing of different kinds of textile fabrics.Keywords: Melia composita, Bark, Natural Dye, Dyed Fabrics, Antifungal activityÂ

    Electroosmosis modulated peristaltic biorheological flow through an asymmetric microchannel : mathematical model

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    A theoretical study is presented of peristaltic hydrodynamics of an aqueous electrolytic nonNewtonian Jeffrey bio-rheological fluid through an asymmetric microchannel under an applied axial electric field. An analytical approach is adopted to obtain the closed form solution for velocity, volumetric flow, pressure difference and stream function. The analysis is also restricted under the low Reynolds number assumption and lubrication theory approximations. Debye-Hückel linearization (i.e. wall zeta potential ≤ 25mV) is also considered. Streamline plots are also presented for the different electro-osmotic parameter, varying magnitudes of the electric field (both aiding and opposing cases) and for different values of the ratio of relaxation to retardation time parameter. Comparisons are also included between the Newtonian and general non-Newtonian Jeffrey fluid cases. The results presented here may be of fundamental interest towards designing lab-on-a-chip devices for flow mixing, cell manipulation, micro-scale pumps etc. Trapping is shown to be more sensitive to an electric field (aiding, opposing and neutral) rather than the electro-osmotic parameter and viscoelastic relaxation to retardation ratio parameter. The results may also help towards the design of organ-on-a-chip like devices for better drug design

    Competition between normal and intruder states inside the "Island of Inversion"

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    The beta decay of the exotic 30Ne (N=20) is reported. For the first time, the low-energy level structure of the N=19, 30Na (Tz = 4), is obtained from beta-delayed gamma spectroscopy using fragment-beta-gamma-gamma coincidences. The level structure clearly displays "inversion", i.e., intruder states with mainly 2p2h configurations displacing the normal states to higher excitation energies. The good agreement in excitation energies and the weak and electromagnetic decay patterns with Monte Carlo Shell Model calculations with the SDPF-M interaction in the sdpf valence space illustrates the small d3/2 - f7/2 shell gap. The relative position of the "normal dominant" and "intruder dominant" excited states provides valuable information to understand better the N=20 shell gap.Comment: 4 pages, 5 figure

    SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications

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    Ground-based observations have insufficient spatial coverage to assess long-term human exposure to fine particulate matter (PM2.5) at the global scale. Satellite remote sensing offers a promising approach to provide information on both short-and long-term exposure to PM2.5 at local-to-global scales, but there are limitations and outstanding questions about the accuracy and precision with which ground-level aerosol mass concentrations can be inferred from satellite remote sensing alone. A key source of uncertainty is the global distribution of the relationship between annual average PM2.5 and discontinuous satellite observations of columnar aerosol optical depth (AOD). We have initiated a global network of ground-level monitoring stations designed to evaluate and enhance satellite remote sensing estimates for application in health-effects research and risk assessment. This Surface PARTiculate mAtter Network (SPARTAN) includes a global federation of ground-level monitors of hourly PM2.5 situated primarily in highly populated regions and collocated with existing ground-based sun photometers that measure AOD. The instruments, a three-wavelength nephelometer and impaction filter sampler for both PM2.5 and PM10, are highly autonomous. Hourly PM2.5 concentrations are inferred from the combination of weighed filters and nephelometer data. Data from existing networks were used to develop and evaluate network sampling characteristics. SPARTAN filters are analyzed for mass, black carbon, water-soluble ions, and metals. These measurements provide, in a variety of regions around the world, the key data required to evaluate and enhance satellite-based PM2.5 estimates used for assessing the health effects of aerosols. Mean PM2.5 concentrations across sites vary by more than 1 order of magnitude. Our initial measurements indicate that the ratio of AOD to ground-level PM2.5 is driven temporally and spatially by the vertical profile in aerosol scattering. Spatially this ratio is also strongly influenced by the mass scattering efficiency.Fil: Snider, G.. Dalhousie University Halifax; CanadáFil: Weagle, C. L.. Dalhousie University Halifax; CanadáFil: Martin, R. V.. Dalhousie University Halifax; Canadá. University of Cambridge; Reino UnidoFil: van Donkelaar, A.. Dalhousie University Halifax; CanadáFil: Conrad, K.. Dalhousie University Halifax; CanadáFil: Cunningham, D.. Dalhousie University Halifax; CanadáFil: Gordon, C.. Dalhousie University Halifax; CanadáFil: Zwicker, M.. Dalhousie University Halifax; CanadáFil: Akoshile, C.. University of Ilorin; NigeriaFil: Artaxo, P.. Governo Do Estado de Sao Paulo; BrasilFil: Anh, N. X.. Vietnam Academy of Science and Technology. Institute of Geophysics; VietnamFil: Brook, J.. University of Toronto; CanadáFil: Dong, J.. Tsinghua University; ChinaFil: Garland, R. M.. North-West University; SudáfricaFil: Greenwald, R.. Rollins School of Public Health; Estados UnidosFil: Griffith, D.. Council for Scientific and Industrial Research; SudáfricaFil: He, K.. Tsinghua University; ChinaFil: Holben, B. N.. NASA Goddard Space Flight Center; Estados UnidosFil: Kahn, R.. NASA Goddard Space Flight Center; Estados UnidosFil: Koren, I.. Weizmann Institute Of Science Israel; IsraelFil: Lagrosas, N.. Manila Observatory, Ateneo de Manila University campus; FilipinasFil: Lestari, P.. Institut Teknologi Bandung; IndonesiaFil: Ma, Z.. Rollins School of Public Health; Estados UnidosFil: Vanderlei Martins, J.. University of Maryland; Estados UnidosFil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rudich, Y.. Weizmann Institute Of Science Israel; IsraelFil: Salam, A.. University Of Dhaka; BangladeshFil: Tripathi, S. N.. Indian Institute Of Technology, Kanpur; IndiaFil: Yu, C.. Rollins School of Public Health; Estados UnidosFil: Zhang, Q.. Tsinghua University; ChinaFil: Zhang, Y.. Tsinghua University; ChinaFil: Brauer, M.. University of British Columbia; CanadáFil: Cohen, A.. Health Effects Institute; Estados UnidosFil: Gibson, M. D.. Dalhousie University Halifax; CanadáFil: Liu, Y.. Rollins School of Public Health; Estados Unido

    Observations of the BL Lac Object 3C 66A with STACEE

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    We present the analysis and results of recent high-energy gamma-ray observations of the BL Lac object 3C 66A conducted with the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE). During the 2003-2004 observing season, STACEE extensively observed 3C 66A as part of a multiwavelength campaign on the source. A total of 33.7 hours of data was taken on the source, plus an equivalent-duration background observation. After cleaning the data set a total of 16.3 hours of live time remained, and a net on-source excess of 1134 events was seen against a background of 231742 events. At a significance of 2.2 standard deviations this excess is insufficient to claim a detection of 3C 66A, but is used to establish flux upper limits for the source.Comment: Accepted for publication in the Astrophysical Journa

    Enhanced Room Temperature Coefficient of Resistance and Magneto-resistance of Ag-added La0.7Ca0.3-xBaxMnO3 Composites

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    In this paper we report an enhanced temperature coefficient of resistance (TCR) close to room temperature in La0.7Ca0.3-xBaxMnO3 + Agy (x = 0.10, 0.15 and y = 0.0 to 0.40) (LCBMO+Ag) composite manganites. The observed enhancement of TCR is attributed to the grain growth and opening of new conducting channels in the composites. Ag addition has also been found to enhance intra-granular magneto-resistance. Inter-granular MR, however, is seen to decrease with Ag addition. The enhanced TCR and MR at / near room temperature open up the possibility of the use of such materials as infrared bolometric and magnetic field sensors respectively.Comment: 22 pages of Text + Figs:comments/suggestions([email protected]

    High-harmonic generation from a subwavelength dielectric resonator

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    Higher-order optical harmonics entered the realm of nanostructured solids being observed recently in optical gratings and metasurfaces with a subwavelength thickness. Structuring materials at the subwavelength scale allows us toresonantly enhance the efficiency of nonlinear processes and reduce the size of high-harmonic sources. We report the observation of up to a seventh harmonic generated from a single subwavelength resonator made of AlGaAs material. This process is enabled by careful engineering of the resonator geometry for supporting an optical mode associated with a quasi-bound state in the continuum in the mid-infrared spectral range at around λ = 3.7 μm pump wavelength. The resonator volume measures ~0.1 λ3. The resonant modes are excited with an azimuthally polarized tightly focused beam. We evaluate the contributions of perturbative and nonperturbative nonlinearities to the harmonic generation process. Our work proves the possibility to miniaturize solid-state sources of high harmonics to the subwavelength volumes

    Long XMM observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809: rapid variability, high spin and a soft lag

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    Results are presented from a 500ks long XMM-Newton observation of the Narrow-Line Seyfert 1 galaxy IRAS13224-3809. The source is rapidly variable on timescales down to a few 100s. The spectrum shows strong broad Fe-K and L emission features which are interpreted as arising from reflection from the inner parts of an accretion disc around a rapidly spinning black hole. Assuming a power-law emissivity for the reflected flux and that the innermost radius corresponds to the innermost stable circular orbit, the black hole spin is measured to be 0.988 with a statistical precision better than one per cent. Systematic uncertainties are discussed. A soft X-ray lag of 100s confirms this scenario. The bulk of the power-law continuum source is located at a radius of 2-3 gravitational radii.Comment: 7 pages, 14 figures, submitted to MNRA
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