13,922 research outputs found

    Design and in Vitro Evaluation of a New Nano-Microparticulate System for Enhanced Aqueous-Phase Solubility of Curcumin

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    Curcumin, a yellow polyphenol derived from the turmeric Curcuma longa, has been associated with a diverse therapeutic potential including anti-inflammatory, antioxidant, antiviral, and anticancer properties. However, the poor aqueous solubility and low bioavailability of curcumin have limited its potential when administrated orally. In this study, curcumin was encapsulated in a series of novel nano-microparticulate systems developed to improve its aqueous solubility and stability. The nano-microparticulate systems are based entirely on biocompatible, biodegradable, and edible polymers including chitosan, alginate, and carrageenan. The particles were synthesized via ionotropic gelation. Encapsulating the curcumin into the hydrogel nanoparticles yielded a homogenous curcumin dispersion in aqueous solution compared to the free form of curcumin. Also, the in vitro release profile showed up to 95% release of curcumin from the developed nano-microparticulate systems after 9 hours in PBS at pH 7.4 when freeze-dried particles were used.CONACYTCUPIAPharmac

    Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate

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    Helical spin textures in a 87^{87}Rb F=1 spinor Bose-Einstein condensate are found to decay spontaneously toward a spatially modulated structure of spin domains. This evolution is ascribed to magnetic dipolar interactions that energetically favor the short-wavelength domains over the long-wavelength spin helix. This is confirmed by eliminating the dipolar interactions by a sequence of rf pulses and observing a suppression of the formation of the short-range domains. This study confirms the significance of magnetic dipole interactions in degenerate 87^{87}Rb F=1 spinor gases

    Disk evaporation in a planetary nebula

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    We study the Galactic bulge planetary nebula M 2-29 (for which a 3-year eclipse event of the central star has been attributed to a dust disk) using HST imaging and VLT spectroscopy, both long-slit and integral field. The central cavity of M 2-29 is filled with a decreasing, slow wind. An inner high density core is detected, with radius less than 250 AU, interpreted as a rotating gas/dust disk with a bipolar disk wind. The evaporating disk is argued to be the source of the slow wind. The central star is a source of a very fast wind (1000 km/s). An outer, partial ring is seen in the equatorial plane, expanding at 12 km/s. The azimuthal asymmetry is attributed to mass-loss modulation by an eccentric binary. M 2-29 presents a crucial point in disk evolution, where ionization causes the gas to be lost, leaving a low-mass dust disk behind.Comment: 11 pages, accepted for publication in "Astronomy and Astrophysics

    INSTABILITY AND TRADE IN CURRENCY AREAS

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    We present a model of a currency area in which labor markets of country members are isolated but there is trade among these countries. When a country experiences a negative (resp. positive) shock, inflation goes down (up). This causes two effects. On the one hand the real interest rate of this country increases (decreases). On the other hand the goods produced in this country become more (less) competitive. We show that the stability of the system depends on several factors, including a large competitive effect, how inflation expectations are formed and fiscal policy. In general, stability requires a trade-off between the rationality of expectations and budget balance.

    Identification of Lead and Cadmium Levels in White Cabbage (Brassica Rapa L.), Soil, and Irrigation Water of Urban Agricultural Sites in the Philippines

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    Urban agriculture comprises a variety of farming systems, ranging from subsistence to fully commercialized agriculture. Pollution from automobile exhaust, industrial and commercialactivities may affect humans, crops, soil, and water in and around urban agriculture areas. The research aimed to investigate the level and distribution of lead (Pb) and cadmium (Cd) in white cabbage (Brassica rapa L.), soil, and irrigation water taken from urban sites. The research was conducted in Las Piñas and Parañaque, Metro Manila, Philippines. The field area was divided into three sections based on its distance from the main road (0, 25, and 50 m). Irrigation water was taken from canal (Las Piñas) and river (Parañaque). Pb and Cd contents of the extract were measured by Atomic Absorption Spectrophotometry. Combined analysis over locations was used. The relationship between distance from the main road and metal contents was measured by Pearson's correlation. Based on combined analyses, highly significant difference over locations was only showed on Cd content in white cabbage. Cd content in white cabbage grown in Parañaque was higher than that cultivated in Las Piñas, while Cd content in the soil between both sites was comparable.The average Pb content (1.09 µg g-1 dry weight) was highest in the white cabbage grown right beside the main road. A similar trend was also observed in the soil, with the highest concentration being recorded at 26 µg g-1 dry weight. There was a negative relationship between distance from the main road and Pb and Cd contents in white cabbage and the soil. Level of Pb in water taken from the canal and river was similar (0.12 mg l-1), whereaslevels of Cd were 0.0084 and 0.0095 mg l-1, respectively. In general, the concentrations of Pb and Cd in white cabbage and soil as well as irrigation water were still in the acceptable limits. In terms of environmental hazards and polluted city environment, it seems that big cities in Indonesia especially Jakarta and Surabaya have the same problem with the Philippines. Therefore, it is suggested that the study on heavy metal contaminationin several crops, especially those grown along the main road, should be conducted

    Are There Local Analogs of Lyman Break Galaxies?

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    To make direct comparisons in the rest-far-ultraviolet between LBGs at z~3 and more local star-forming galaxies, we use HST/STIS to image a set of 12 nearby (z<0.05) HII galaxies in the FUV and a set of 14 luminous compact blue galaxies (LCBGs) at moderate redshift (z~0.5) in the NUV, corresponding to the rest-FUV. We then subject both sets of galaxy images and those of LBGs at z~3 to the same morphological and structural analysis. We find many qualitative and quantitative similarities between the rest-FUV characteristics of distant LBGs and of the more nearby starburst samples, including general morphologies, sizes, asymmetries, and concentrations. Along with some kinematic similarities, this implies that nearby HII galaxies and LCBGs may be reasonable local analogs of distant Lyman break galaxies.Comment: 4 pages, 4 figures. To appear in "Starbursts: from 30 Doradus to Lyman Break Galaxies" 2005, eds. R. de Grijs and R. M. Gonzalez Delgado (Kluwer

    The Nature of Nearby Counterparts to Intermediate Redshift Luminous Compact Blue Galaxies II. CO Observations

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    We present the results of a single-dish beam-matched survey of the three lowest rotational transitions of CO in a sample of 20 local (D < 70 Mpc) Luminous Compact Blue Galaxies (LCBGs). These ~L*, blue, high surface brightness, starbursting galaxies were selected with the same criteria used to define LCBGs at higher redshifts. Our detection rate was 70%, with those galaxies having Lblue<7e9 Lsun no detected. We find the H2 masses of local LCBGs range from 6.6e6 to 2.7e9 Msun, assuming a Galactic CO-to-H2 conversion factor. Combining these results with our earlier HI survey of the same sample, we find that the ratio of molecular to atomic gas mass is low, typically 5-10%. Using a Large Velocity Gradient model, we find that the average gas conditions of the entire ISM in local LCBGs are similar to those found in the centers of star forming regions in our Galaxy, and nuclear regions of other galaxies. Star formation rates, determined from IRAS fluxes, are a few solar masses per year, much higher per unit dynamical mass than normal spirals. If this rate remains constant, the molecular hydrogen depletion time scales are short, 10-200 Myr.Comment: accepted for publication in the ApJ (vol 625
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