905 resultados para Sun shadow


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The sun mushroom is the popular name for the Agaricus blazei Murill fungus, a mushroom native to south-eastern Brazil, which has been frequently used in popular medicine mainly in the form of tea to treat various ailments (stress, diabetes, etc.). In the present study, the genotoxic and/or anti-genotoxic effects ofA. blazei on mammalian cells in culture was assessed by checking the increase or reduction of micronucleus (MN) frequency and comets. The sun mushroom (lineage 99/26) was used as aqueous extracts prepared (2.5%) at three different temperatures (60, 25 and 4°C). The in vitro micronucleus (MN) test in binucleated cells and comet assay were used in V79 cells cultivated in HAM-F10+DMEM medium (1:1), supplemented with 10% of fetal bovine serum. The experiments were divided into four treatment types: 1. Negative control; 2. Positive control with MMS; 3. Treatments with the three forms of extracts (60, 25 and 4°C); and 4. Treatments with the extracts in different associations (simultaneous, pre-treatment, post-treatment and simultaneous after pre-incubation for 1 h) with MMS. None of the A. blazei extracts show genotoxic activity. In the comet assay no protecting effect was found. The results obtained in the MN test showed that the three forms of extracts used had protective activity, suggesting that the compound or active ingredients of A. blazei are always present in these extracts. The greater protective efficiency of the simultaneous treatment and simultaneous treatment with pre-incubation mixture with MMS suggests that the extracts have an antimutagenic action of the desmutagenic type. © 2002 Elsevier Science Ltd. All rights reserved.

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Includes bibliography

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Includes bibliography

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Includes bibliography

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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A new concept for in vitro visual evaluation of sun protection factor (SPF) of cosmetic formulations based on a supramolecular ultraviolet (UV) dosimeter was clearly demonstrated. The method closely parallels the method validated for in vivo evaluation and relies on the determination of the slightest perceptible bleaching of an iron-complex dye/nanocrystallinetitanium dioxide interface (UV dosimeter) in combination with an artificial skin substrate simulating the actual human skin in the presence and absence of a cosmetic formulation. The successful evaluation of SPF was ensured by the similarity of the erythema response of our dosimeter and human skin to UV light irradiation. A good linear correlation of in vitro and in vivo data up to SPF 40 confirmed the effectiveness of such a simple, cheap, and fast method. In short, here we unravel a convenient and accessible visual FPS evaluation method that can help improving the control on cosmetic products contributing to the reduction of skin cancer, one of the critical public health issues nowadays. (C) 2011 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 101:726732, 2012

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This research presents a study of roof thermal efficiency in individual housing for calves exposed to sun and shade through infrared thermography, internal temperature and thermal comfort indexes. Four different individual housing for calves covered with asbestos-free fiber-cement corrugated sheets were evaluated. Three of them were directly exposed to the sun: (i) corrugated sheets painted white in the external surface, (ii) corrugated sheets without painting and (iii) with screen shade fabric installed 0.10m under de internal surface of the corrugated sheet. The fourth individual housing was installed in the shade area and covered with unpainted corrugated fiber-cement sheets. The analysis was taken for 21 days at 11h00min, 14h00min and 17h00min. The results indicate significant variations in the roofing surface temperature and thermal comfort indexes among the treatments exposed to the sun and shade, for all the evaluations during the day. The infrared thermography images were effective for better understanding the heat transfer processes from the roof to the internal environment of the housing.

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Solar infrared colors provide powerful constraints on the stellar effective temperature scale, but they must be measured with both accuracy and precision in order to do so. We fulfill this requirement by using line-depth ratios to derive in a model-independent way the infrared colors of the Sun, and we use the latter to test the zero point of the Casagrande et al. effective temperature scale, confirming its accuracy. Solar colors in the widely used Two Micron All Sky Survey (2MASS) JHK(s) and WISE W1-4 systems are provided: (V - J)(circle dot) = 1.198, (V - H)(circle dot) = 1.484, (V - K-s)(circle dot) = 1.560, (J - H)(circle dot) = 0.286, (J - K-s)(circle dot) = 0.362, (H - K-s)(circle dot) = 0.076, (V - W1)(circle dot) = 1.608, (V - W2)(circle dot) = 1.563, (V - W3)(circle dot) = 1.552, and (V - W4)(circle dot) = 1.604. A cross-check of the effective temperatures derived implementing 2MASS or WISE magnitudes in the infrared flux method confirms that the absolute calibration of the two systems agrees within the errors, possibly suggesting a 1% offset between the two, thus validating extant near-and mid-infrared absolute calibrations. While 2MASS magnitudes are usually well suited to derive T-eff, we find that a number of bright, solar-like stars exhibit anomalous WISE colors. In most cases, this effect is spurious and can be attributed to lower-quality measurements, although for a couple of objects (3%+/- 2% of the total sample) it might be real, and may hint at the presence of warm/hot debris disks.

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The magnetic field in the local interstellar medium (ISM) provides a key indicator of the galactic environment of the Sun and influences the shape of the heliosphere. We have studied the interstellar magnetic field (ISMF) in the solar vicinity using polarized starlight for stars within 40 pc of the Sun and 90 degrees of the heliosphere nose. In Frisch et al. (Paper I), we developed a method for determining the local ISMF direction by finding the best match to a group of interstellar polarization position angles obtained toward nearby stars, based on the assumption that the polarization is parallel to the ISMF. In this paper, we extend the analysis by utilizing weighted fits to the position angles and by including new observations acquired for this study. We find that the local ISMF is pointed toward the galactic coordinates l, b = 47 degrees +/- 20 degrees, 25 degrees +/- 20 degrees. This direction is close to the direction of the ISMF that shapes the heliosphere, l, b = 33 degrees +/- 4 degrees, 55 degrees +/- 4 degrees, as traced by the center of the "Ribbon" of energetic neutral atoms discovered by the Interstellar Boundary Explorer (IBEX) mission. Both the magnetic field direction and the kinematics of the local ISM are consistent with a scenario where the local ISM is a fragment of the Loop I superbubble. A nearby ordered component of the local ISMF has been identified in the region l approximate to 0 degrees -> 80 degrees and b approximate to 0 degrees -> 30 degrees, where PlanetPol data show a distance-dependent increase of polarization strength. The ordered component extends to within 8 pc of the Sun and implies a weak curvature in the nearby ISMF of +/- 0 degrees.25 pc(-1). This conclusion is conditioned on the small sample of stars available for defining this rotation. Variations from the ordered component suggest a turbulent component of +/- 23 degrees. The ordered component and standard relations between polarization, color excess, and H-o column density predict a reasonable increase of N(H) with distance in the local ISM. The similarity of the ISMF directions traced by the polarizations, the IBEX Ribbon, and pulsars inside the Local Bubble in the third galactic quadrant suggest that the ISMF is relatively uniform over spatial scales of 8-200 pc and is more similar to interarm than spiral-arm magnetic fields. The ISMF direction from the polarization data is also consistent with small-scale spatial asymmetries detected in GeV-TeV cosmic rays with a galactic origin. The peculiar geometrical relation found earlier between the cosmic microwave background dipole moment, the heliosphere nose, and the ISMF direction is supported by this study. The interstellar radiation field at +/- 975 angstrom does not appear to play a role in grain alignment for the low-density ISM studied here.