Interferómetro en 408 Mc/s

e enumeran datos obtenidos hasta el presente en la estación Las Acacias, con dos antenas. Interferómetro de diez antenas con el uso de cable coaxil con aire como dieléctrico. Instalación del sistema en el Parque Pereyra.Asociación Argentina de Astronomí

Cambios de la polarización de radiobursts en la región MCMATH 13403

La región activa Mc Math 13403 dió lugar a un gran incremento de la actividad solar en el 28-6-74 y el 10-7-74. La observación de la polarización de radiobursts en 408 MHz ha mostrado cambios del sentido de polarización dentro del minuto. Estas evidencias observacionales son explicables considerando que emiten zonas distintas de la misma región activa. Se haca una asociación con fulguraciones y observaciones de radio en otras frecuencias.Asociación Argentina de Astronomí

Fotómetro fotoeléctrico Piloto

Se presenta el sistema electrónico total de un fotómetro fotoeléctrico piloto, dando las principales características de cada uno de los elementos que lo componen. Para una mejor interpretación sobre el funcionamiento del equipo se presentan diagramas de bloques y detalles del equipo contador de cuatro canales, interfase e impresor. El instrumento permite ser controlado por una micro-computadora y puede entregar los valores medidos a la barra de datos de ésta. Los detalles sobre la utilización de este instrumento, sumamente versátil, son dados con el objeto de que la comunidad astronómica pueda proyectar futuras observaciones en función de que será parte permanente del telescopio de 75 cm de El Leóncito.Asociación Argentina de Astronomí

Interferómetro en 408 Mc/s

e enumeran datos obtenidos hasta el presente en la estación Las Acacias, con dos antenas. Interferómetro de diez antenas con el uso de cable coaxil con aire como dieléctrico. Instalación del sistema en el Parque Pereyra.Asociación Argentina de Astronomí

Interferómetro en 408 Mc/s

e enumeran datos obtenidos hasta el presente en la estación Las Acacias, con dos antenas. Interferómetro de diez antenas con el uso de cable coaxil con aire como dieléctrico. Instalación del sistema en el Parque Pereyra.Asociación Argentina de Astronomí

Morfología de bursts en 400 MHz y sus relaciones físicas

Se asocia la morfología del radioburst en 408 MHz con eventos ópticos, de radio y rayos X, bursts homólogos.Asociación Argentina de Astronomí

El polarímetro digital rotatorio del OALP

Se ha concluido el proyecto y se está encarando al construcción de un polarímetro estelar que funcionará como una modificación del fotómetro UBVRI actualmente en uso sin cambiar su capacidad actual. La posición del analizador deriva la salida de la fotomultiplicadora a cuatro contadores independientes. Los resultados de los conteos se traducen fácilmente a los parámetros de Stokes normalizados y q. Se espera eliminar el centelleo como fuente de error trabajando en la cercanía de 100 Hz.Asociación Argentina de Astronomí

Thymol and Thymus vulgaris extract protects human keratinocyte cell line (HaCaT) from UVA and UVB damage

Objective: The aims of our study were to characterize ultraviolet (UV)A- and UVB-induced damages in a keratinocytes cell line (HaCaT), and to evaluate the protective capacities two plant-derivative compounds, namely Thymus vulgaris L leaf extract and thymol, its major component. A polyphenol rich diet has gained wide attention and it is now considered to be a protective agent for human skin, which can be over-exposed to environmental factors and in particular UV light. Methods: Cells were pretreated for 1 h, in serum-free medium, with thymol (1 \u3bcg/ml) or Thymus vulgaris L (1.82 \u3bcg/ml) then exposed to different UVA (8-24 J/cm2) or UVB doses (0.016-0.72 J/cm2). Immediately after the UV exposure the intracellular redox status was evaluated by reactive oxygen species quantification and apoptotic events. Genotoxic aspects were evaluated 24 h after the end of irradiations using the alkaline comet assay and the immunostaining of phosphorylated H2AX histone protein (detected 1 h after the end of UV exposure). Results: The pre-treatment of our experimental model with the two substances confirmed an antioxidant action and anti-apoptotic effect by reducing the cells percentage (sub-G1 phase). Furthermore, thymol and extract of Thymus vulgaris L were able to reduce genotoxic damage. The alkaline comet assay showed that the two substances were capable to decrease DNA damage. Also in this case, Thymus vulgaris L extract is more effective than thymol in decreasing genotoxicity markers. Conclusions: Our results confirmed the more oxidant UVA and more genotoxic UVB effects. Regarding the protective effect of thymol and Thymus vulgaris L extract, data obtained proved their antioxidant and free-radical scavenging ability as known for phenolic (which our compounds belong to) and polyphenolic compounds. Thymol and mainly Thymus vulgaris L extract were also able to reduce the direct genotoxic damage

Effects of UV rays and natural compound repairs using an ex-vivo human skin model: morphological and genotoxicological analysis

Among the key factors in skin disorders such as wrinkling, dryness and photo-aging, the exposure to solar ultraviolet (UV) radiation plays a central role (1). Recently, compounds rich in polyphenols such as Thymus Vulgaris Leaf (TVL) extract and its major component Thymol (T) have been proposed in the prevention of UV-induced skin damages (2). Experiments were carried out in a human ex-vivo skin model, in which biopsies were obtained from aesthetic surgery of healthy 20-40 year-old women (n=6) after written informed consent (3). After 24 h, samples were pre-treated for 1 h with comparable concentrations of two compounds (TVL: 1.82 \ub5g/mL and T: 1 \ub5g/mL) before being irradiated with different UVB doses (0.24 J/cm2 to 0.72 J/cm2) or UVA radiation (8 J/cm2 to 32 J/cm2). Samples were harvested 24 h after irradiation and were processed both for light and transmission electron microscopy.Cell proliferation, Lactate Dehydrogenase assay, alkaline comet test, and histone H2AX phosphorylationwere evaluated. Both UVB and UVA induced an early inhibition of cell proliferation and DNA damage compared with respective controls. In particular, UVB rays were always more cytotoxic and genotoxic than UVA. The T-pretreatment showed a reduction of UVB-induced structural/ultrastructural and genotoxic damages. These results suggest that polyphenol fraction of tested substances may be useful for skin photoprotection after UV radiation damage in an ex-vivo human skin model. The present study suggests that this experimental setting can be a reliable approach for safety evaluation of UV skin exposure

Comparative antioxidant activity of cultivated and wild Vaccinium species investigated by EPR, human neutrophil burst and COMET assay

objectives: The Vaccinium (V.) spp. berries are considered a source of antioxidants, mainly belonging to polyphenols, specifically flavonoids and anthocyanins. Wild genotypes generally contain more antioxidants than cultivated counterparts. So, seven different antioxidants assays on extracts from cultivated and wild Vaccinium berries were performed, to evaluate their difference in terms of bioactivity on oxidative protection and minimum dosage to have a significant action. Materials and Methods: Four cell-free antioxidant assays (ABTS radical scavenging and electronic paramagnetic resonance using Fremy's salt, superoxide anion and hydroxyl radical), and three assays on human cells (two luminol amplified chemiluminescence, LACL, one on DNA damage, COMET) were used to measure the effects of cultivated blueberry (V. corymbosum) and wild bilberry (V. myrtillus) on the differently induced oxidative stress. Concentrations vs activity patterns were obtained by successive dilutions of extracts in order to identify both EC50 and minimum significant activity (MSA). Results: All the assays (except for the hydroxyl radical scavenging) showed a good relationship mainly with anthocyanin and polyphenol content and the significant greater activity of wild Vaccinium extracts. In fact, LACL data gave an EC50 of 11.8 and an MSA of 5.2 g were calculated as fresh weight dosage in cultivated berries, compared with lower doses in wild berries, EC50 of 5.7 g and MSA of 3.4 g. Conclusions: Wild Vaccinium extracts averaged 3.04 and 2.40 fold more activity than cultivated extracts by EC50 and MSA, respectively. COMET assay confirmed the stronger action on DNA protection in wild samples