Two short mass-loss events that unveil the binary heart of Minkowski's Butterfly Nebula

Studying the appearance and properties of bipolar winds is critical to understand the stellar evolution from the AGB to the planetary nebula (PN) phase. Many uncertainties exist regarding the presence and role of binary stellar systems, mainly due to the deficit of conclusive observational evidences. We investigate the extended equatorial distribution around the early bipolar planetary nebula M 2-9 ("Minkowski's Butterfly Nebula") to gather new information on the mechanism of the axial ejections. Interferometric millimeter observations of molecular emission provide the most comprehensive view of the equatorial mass distribution and kinematics in early PNe. Here we present subarcsecond angular-resolution observations of the 12CO J=2-1 line and continuum emission with the Plateau de Bure interferometer. The data reveal two ring-shaped and eccentric structures at the equatorial basis of the two coaxial optical lobes. The two rings were formed during short mass-loss episodes (~ 40 yr), separated by ~ 500 yr. Their positional and dynamical imprints provide evidence of the presence of a binary stellar system at the center, which yields critical information on its orbital characteristics, including a mass estimate for the secondary of ~< 0.2 \ms. The presence of a stellar system with a modest-mass companion at the center of such an elongated bipolar PN strongly supports the binary-based models, because these are more easily able to explain the frequent axisymmetric ejections in PNe.Comment: 8 page

Acute hepatic and renal toxicity assessment of Euphorbia huanchahana (Klotzsch & Garcke) Boissier (Huachangana) in Holtzman rats

Background: Euphorbia huachahana (Klotzch & Garcke) Boissier (Huachangana) (EhKGBh) has been used for over a century for medicinal purposes in the Peruvian population; however, its safety and possible toxic effects of use have not been reported. The purpose of this study was to determine the acute hepatic and renal toxicity of EhKGBh in Holtzman rats. Methods: Analytical and experimental study. The population consisted of 52 rats of both sexes weighing between 300 and 350 g divided into four groups: G1 and G2 EhKGBh groups (26 rats each) and two control groups (10 rats each). The experimental group was administered EhKGBh at a single dose of 2000 mg/kg P.O. to demonstrate toxicity during the 14-day follow-up. A daily assessment of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), and conjugated bilirubin (CBIL) was performed. Results: Evaluation of the liver tissue showed mild changes in inflammation, predominantly vascular, with small clots. Kidney tissue did not show inflammatory or necrotic changes. However, we showed differences in the weight of the rats between both groups (p < 0.004) and significant increases in TBIL (0.98–1.07 mg/dL), CBIL (0.43–0.45 mg/dL), AST (126.4–141.8 U/L), and ALP (254–298 U/L) but not ALT (39.7–41.1 U/L) (p < 0.05). Conclusion: The single dose of EhKGBh extract at 2000 mg/kg has no toxicity, and there is no change in tissue toxicity during the 14-day follow-up.Campus Lima Centr

Casimir-like tunneling-induced electronic forces

We study the quantum forces that act between two nearby conductors due to electronic tunneling. We derive an expression for these forces by calculating the flux of momentum arising from the overlap of evanescent electronic fields. Our result is written in terms of the electronic reflection amplitudes of the conductors and it has the same structure as Lifshitz's formula for the electromagnetically mediated Casimir forces. We evaluate the tunneling force between two semiinfinite conductors and between two thin films separated by an insulating gap. We discuss some applications of our results.Comment: 8 pages, 3 figs, submitted to Proc. of QFEXT'05, to be published in J. Phys.

Copper: Synthesis Techniques in Nanoscale and Powerful Application as an Antimicrobial Agent

Nanosized metal particles show specific physical and chemical properties that allow the creation of new composites materials, which are important for multiple applications in biology and medicine such as infections control. Metal nanoparticles, mainly copper, exhibit excellent inhibitory effect on Gram-positive and Gram-negative bacteria; therefore the exploration about the efficient, economical, and friendly environmental technics to synthesize inorganic nanoparticles is imperative. In this work a brief overview of the several methods is made including the comparison of the methods, mainly between sonochemical, microwave, and chemical routes. It allows determining the optimal parameters and technical conditions to synthesize copper nanoparticles with physical and chemical properties suitable for the oral bacterial inhibition

INTEGRAL-ISGRI observations of the CygOB2 region: earching for hard X-ray point sources in a region containing several non-thermal emitting massive stars

Aims: We analyze INTEGRAL-ISGRI data in order to probe the hard X-ray emission (above 20 keV) from point sources in the Cyg OB2 region and to investigate the putative non-thermal high-energy emission from early-type stars (Wolf-Rayet and O-type stars). Among the targets located in the field of view, we focus on the still unidentified EGRET source 3EG 2033+4118 that may be related to massive stars known to produce non-thermal emission in the radio domain, and on the wide colliding-wind binary WR 140. Methods: Using a large set of data obtained with the IBIS-ISGRI imager onboard INTEGRAL, we run the OSA software package in order to find point sources in the fully coded field of view of the instrument. Results: Our data do not allow the detection of a lower-energy counterpart of 3EG J2033+4118 nor of any other new point sources in the field of view, and we derive upper limits on the high-energy flux for a few targets: 3EG J2033+4118, TeV J2032+4130, WR140, WR146 and WR147. The results are discussed in the context of the multiwavelength investigation of these objects. Conclusions: The upper limits derived are valuable constraints for models aimed at understanding the acceleration of particles in non-thermal emitting massive stars, and of the still unidentified very-high gamma-ray source TeV J2032+4130.Comment: 6 page, 2 figures including one figure in GIF format, accepted for publication by A&

Can the gamma-ray source 3EG J2033+4118 be produced by the stellar system Cyg OB2 No.5?

We discuss the possibility that the stellar system Cyg OB2 No.5 can be a gamma-ray source in the light of recent EGRET and radio data. This system is formed by an O7 Ia + Ofpe/WN9 contact binary. A third star, probably a B0 V star also associated with the system, is located at $\sim 1700$ AU from the primary. We estimate the expected gamma-ray luminosity from the colliding winds region, the terminal shock of the wind, and the unstable zone at the base of the wind, and conclude that, under very reasonable assumptions, Cyg OB2 No.5 can generate about a half of the gamma-ray flux detected from the positionally coincident source 3EG J2033+4118. We suggest, then, that other O stars belonging to the association, also placed within the 95 % probability EGRET location contour, could contribute to the observed gamma-ray flux.Comment: Accepted for publication in Astronomy and Astrophysic

New molecular approaches in adipogenesis regulation: The connexin 43 role

Indexación: Scopus; Redalyc.La prevalencia de la obesidad a nivel mundial se ha incrementado rápidamente durante los últimos años debido principalmente a los cambios en el estilo de vida de la población con un aumento significativo en el consumo de energía y disminución de los niveles de actividad física. Es por esto que la comunidad científica está interesada en comprender de forma más profunda los mecanismos que regulan la fisiopatología de la obesidad. Dentro de los diferentes blancos de estudio se encuentra la adipogénesis, cuyo entendimiento es fundamental para comprender el desarrollo de la obesidad y las patologías asociadas a esta. Recientemente ha surgido importantes evidencias que involucran a la proteína de canales de “Gap Junction” conexina 43 (Cx43) en la regulación de los procesos relacionados con adipogénesis, cuyo papel es básicamente anti-adipogénico, sin embargo, nuevas funciones de Cx43 en la regulación de la formación del tejido adiposo siguen descubriéndose.The global prevalence of obesity has been increased rapidly over the past few years mainly due to changes in the lifestyle of the population with a significant increase in energy consumption and decreased levels of physical activity. As a result, the scientific community is interested in a deeper understanding of the mechanisms that regulate the pathophysiology of obesity. In this context, adipogenesis process is an important target of study to understand the obesity and associated pathologies. Recently has been emerged important evidence that involve gap junction channel protein connexin 43 (Cx43) in the regulation of processes related to adipogenesis, whose role is fundamentally anti-adipogenic. However, new functions of Cx43 in the regulation of adipose tissue function also continued to emerge.http://www.redalyc.org/articulo.oa?id=5594990800

The Carnegie Supernova Project. I. Third Photometry Data Release of Low-redshift Type Ia Supernovae and Other White Dwarf Explosions

We present final natural-system optical (ugriBV) and near-infrared (YJH) photometry of 134 supernovae (SNe) with probable white dwarf progenitors that were observed in 2004-2009 as part of the first stage of the Carnegie Supernova Project (CSP-I). The sample consists of 123 Type Ia SNe, 5 Type Iax SNe, 2 super-Chandrasekhar SN candidates, 2 Type Ia SNe interacting with circumstellar matter, and 2 SN 2006bt-like events. The redshifts of the objects range from to 0.0835; the median redshift is 0.0241. For 120 (90%) of these SNe, near-infrared photometry was obtained. Average optical extinction coefficients and color terms are derived and demonstrated to be stable during the five CSP-I observing campaigns. Measurements of the CSP-I near-infrared bandpasses are also described, and near-infrared color terms are estimated through synthetic photometry of stellar atmosphere models. Optical and near-infrared magnitudes of local sequences of tertiary standard stars for each supernova are given, and a new calibration of Y-band magnitudes of the Persson et al. standards in the CSP-I natural system is presented.Fil: Krisciunas, Kevin. Texas A&M University; Estados UnidosFil: Contreras, Carlos. University Aarhus; Dinamarca. Las Campanas Observatory; ChileFil: Burns, Christopher R.. Las Campanas Observatory; ChileFil: Phillips, M. M.. Las Campanas Observatory; ChileFil: Stritzinger, Maximilian D.. Las Campanas Observatory; Chile. University Aarhus; DinamarcaFil: Morrell, Nidia Irene. Las Campanas Observatory; ChileFil: Hamuy, Mario. Universidad de Chile; ChileFil: Anais, Jorge. Las Campanas Observatory; ChileFil: Boldt, Luis. Las Campanas Observatory; ChileFil: Busta, Luis. Las Campanas Observatory; ChileFil: Campillay, Abdo. Las Campanas Observatory; ChileFil: Castellón, Sergio. Las Campanas Observatory; ChileFil: Folatelli, Gaston. Las Campanas Observatory; Chile. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Freedman, Wendy L.. University of Chicago; Estados UnidosFil: González, Consuelo. Las Campanas Observatory; ChileFil: Hsiao, Eric Y.. Florida State University; Estados Unidos. University Aarhus; Dinamarca. Las Campanas Observatory; ChileFil: Krzeminski, Wojtek. Las Campanas Observatory; ChileFil: Persson, Sven Eric. Carnegie Observatories;Fil: Roth, Miguel. Gmto Corporation; Chile. Las Campanas Observatory; ChileFil: Salgado, Francisco. Leiden Observatory Research Institute; . Las Campanas Observatory; ChileFil: Serón, Jacqueline. Las Campanas Observatory; Chile. Cerro Tololo Inter American Observatory; ChileFil: Suntzeff, Nicholas B.. Texas A&M University; Estados UnidosFil: Torres, Simón. Soar Telescope; Chile. Las Campanas Observatory; ChileFil: Filippenko, Alexei V.. University of California at Berkeley; Estados UnidosFil: Li, Weidong. University of California at Berkeley; Estados UnidosFil: Madore, Barry F.. Jet Propulsion Laboratory, California Institute Of Technology; . Las Campanas Observatory; ChileFil: DePoy, D.L.. Texas A&M University; Estados UnidosFil: Marshall, Jennifer L.. Texas A&M University; Estados UnidosFil: Rheault, Jean Philippe. Texas A&M University; Estados UnidosFil: Villanueva, Steven. Texas A&M University; Estados Unidos. Ohio State University; Estados Unido

The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae

The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper.Comment: Updated a couple of small error