Orbital and Physical Properties of the σ Ori Aa, Ab, B Triple System

We provide a complete characterization of the astrophysical properties of the σ Ori Aa, Ab, B hierarchical triple system and an improved set of orbital parameters for the highly eccentric σ Ori Aa, Ab spectroscopic binary. We compiled a spectroscopic data set comprising 90 high-resolution spectra covering a total time span of 1963 days. We applied the Lehman-Filhés method for a detailed orbital analysis of the radial velocity curves and performed a combined quantitative spectroscopic analysis of the σ Ori Aa, Ab, B system by means of the stellar atmosphere code FASTWIND. We used our own plus other available information on photometry and distance to the system for measuring the radii, luminosities, and spectroscopic masses of the three components. We also inferred evolutionary masses and stellar ages using the Bayesian code BONNSAI. The orbital analysis of the new radial velocity curves led to a very accurate orbital solution of the σ Ori Aa, Ab pair. We provided indirect arguments indicating that σ Ori B is a fast-rotating early B dwarf. The FASTWIND+BONNSAI analysis showed that the Aa, Ab pair contains the hottest and most massive components of the triple system while σ Ori B is a bit cooler and less massive. The derived stellar ages of the inner pair are intriguingly younger than the one widely accepted for the σ Orionis cluster, at 3 ± 1 Ma. The outcome of this study will be of key importance for a precise determination of the distance to the σ Orionis cluster, the interpretation of the strong X-ray emission detected for σ Ori Aa, Ab, B, and the investigation of the formation and evolution of multiple massive stellar systems and substellar objects.

CIE L*a*b*: comparison of digital images obtained photographically by manual and automatic modes

The aim of this study was to analyze the color alterations performed by the CIE L*a*b* system in the digital imaging of shade guide tabs, which were obtained photographically according to the automatic and manual modes. This study also sought to examine the observers' agreement in quantifying the coordinates. Four Vita Lumin Vaccum shade guide tabs were used: A3.5, B1, B3 and C4. An EOS Canon digital camera was used to record the digital images of the shade tabs, and the images were processed using Adobe Photoshop software. A total of 80 observations (five replicates of each shade according to two observers in two modes, specifically, automatic and manual) were obtained, leading to color values of L*, a* and b*. The color difference (AE) between the modes was calculated and classified as either clinically acceptable or unacceptable. The results indicated that there was agreement between the two observers in obtaining the L*, a* and b* values related to all guides. However, the B1, B3, and C4 shade tabs had AE values classified as clinically acceptable (Delta E = 0.44, Delta E = 2.04 and Delta E = 2.69, respectively). The A3.5 shade tab had a AE value classified as clinically unacceptable (Delta E = 4.17), as it presented higher values for luminosity in the automatic mode (L* = 54.0) than in the manual mode (L* = 50.6). It was concluded that the B1, B3 and C4 shade tabs can be used at any of the modes in digital camera (manual or automatic), which was a different finding from that observed for the A3.5 shade tab.

Physicochemical analysis of Ti-Si-B powder aalloys

Titanium alloys of Ti-Si-B system were manufactured by blended elemental powder method using Ti, Si and B powders as starting materials. It was found that uniaxial and isostatic pressing followed by hot pressing at around 1000°C, for 20 minutes, provided good densification of such alloys. The physicochemical studies were performed by means of scanning electron microscopy, X-ray diffraction, atomic force microscopy and microindentation/wear tests. The investigations revealed a multiphase microstructure formed mainly by α-titanium, Ti6Si2B, Ti5Si3, TiB and Ti3Si phases. The phase transformations after pressureless sintering at 1200°C was also studied by X-ray diffraction for the Ti-18Si-6B composition. As stated in some other researches, these intermetallics in the α-titanium matrix provide high wear resistance and hardness, with the best wear rate of 0.2 mm3/N.m and the highest hardness of around 1300 HV. © (2012) Trans Tech Publications, Switzerland.

NF-κB activation mediates crystal translocation and interstitial inflammation in adenine overload nephropathy

Adenine overload promotes intratubular crystal precipitation and interstitial nephritis. We showed recently that these abnormalities are strongly attenuated in mice knockout for Toll-like receptors-2, -4, MyD88, ASC, or caspase-1. We now investigated whether NF-κB activation also plays a pathogenic role in this model. Adult male Munich-Wistar rats were distributed among three groups: C (n = 17), receiving standard chow; ADE (n = 17), given adenine in the chow at 0.7% for 1 wk and 0.5% for 2 wk; and ADE + pyrrolidine dithiocarbamate (PDTC; n = 14), receiving adenine as above and the NF-κB inhibitor PDTC (120 mg•kg-1•day-1 in the drinking water). After 3 wk, widespread crystal deposition was seen in tubular lumina and in the renal interstitium, along with granuloma formation, collagen accumulation, intense tubulointerstitial proliferation, and increased interstitial expression of inflammatory mediators. Part of the crystals were segregated from tubular lumina by a newly formed cell layer and, at more advanced stages, appeared to be extruded to the interstitium. p65 nuclear translocation and IKK-α increased abundance indicated activation of the NF-κB system. PDTC treatment prevented p65 migration and normalized IKK-α, limited crystal shift to the interstitium, and strongly attenuated interstitial fibrosis/inflammation. These findings indicate that the complex inflammatory phenomena associated with this model depend, at least in part, on NF-κB activation, and suggest that the NF-κB system may become a therapeutic target in the treatment of chronic kidney disease.

BIOCHEMICAL PROPERTIES OF GABA (B) RECEPTORS (BACLOFEN, ADENYLATE CYCLASE, CYCLIC-AMP, PHOSPHOLIPASE, PROTEIN KINASE C)

(gamma)-Aminobutyric acid (GABA), a neurotransmitter in the mammalian central nervous system, influences neuronal activity by interacting with at least two pharmacologically and functionally distinct receptors. GABA(,A) receptors are sensitive to blockade by bicuculline, are associated with benzodiazepine and barbiturate binding sites, and mediate chloride flux. The biochemical and pharmacolocal properties of GABA(,B) receptors, which are stereoselectively activated by (beta)-p-chlorophenyl GABA (baclofen), are less well understood. The aim of this study was to define these features of GABA(,B) receptors, with particular emphasis on their possible relationship to the adenylate cyclase system in brain.^ By themselves, GABA agonists have no effect on cAMP accumulation in rat brain slices. However, some GABA agonists markedly enhance the cAMP accumulation that results from exposure to norepinephrine, adenosine, VIP, and cholera toxin. Evidence that this response is mediated by the GABA(,B) system is provided by the finding that it is bicuculline-insensitive, and by the fact that only those agents that interact with GABA(,B) binding sites are active in this regard. GABA(,B) agonists are able to enhance neurotransmitter-stimulated cAMP accumulation in only certain brain regions, and the response is not influenced by phosphodiesterase inhibitors, although is totally dependent on the availability of extracellular calcium. Furthermore, data suggest that inhibition of phospholipase A(,2), a calcium-dependent enzyme, decreases the augmenting response to baclofen, although inhibitors of arachidonic acid metabolism are without effect. These findings indicate that either arachidonic acid or lysophospholipid, products of PLA(,2)-mediated degradation of phospholipids, mediates the augmentation. Moreover, phorbol esters, compounds which directly activate protein kinase C, were also found to enhance neurotransmitter-stimulated cAMP accumulation in rat brain slices. Since this enzyme is known to be stimulated by unsaturated fatty acids such as arachidonate, it is proposed that GABA(,B) agonists enhance cAMP accumulation by fostering the production of arachidonic acid which stimulates protein kinase C, leading to the phosphorylation of some component of the adenylate cyclase system. Thus, GABA, through an interaction with GABA(,B) receptors, modulates neurotransmitter receptor responsiveness in brain. The pharmocological manipulation of this response could lead to the development of therapeutic agents having a more subtle influence than current drugs on central nervous system function. ^

Desarrollo de software de control y medida para goniofotómetro de tipo B

El proyecto trata del desarrollo de un software para realizar el control de la medida de la distribución de intensidad luminosa en luminarias LED. En el trascurso del proyecto se expondrán fundamentos teóricos sobre fotometría básica, de los cuales se extraen las condiciones básicas para realizar dicha medida. Además se realiza una breve descripción del hardware utilizado en el desarrollo de la máquina, el cual se basa en una placa de desarrollo Arduino Mega 2560, que, gracias al paquete de Labview “LIFA” (Labview Interface For Arduino”), será posible utilizarla como tarjeta de adquisición de datos mediante la cual poder manejar tanto sensores como actuadores, para las tareas de control. El instrumento de medida utilizado en este proyecto es el BTS256 de la casa GigaHerzt-Optik, del cual se dispone de un kit de desarrollo tanto en lenguaje C++ como en Labview, haciendo posible programar aplicaciones basadas en este software para realizar cualquier tipo de adaptación a las necesidades del proyecto. El software está desarrollado en la plataforma Labview 2013, esto es gracias a que se dispone del kit de desarrollo del instrumento de medida, y del paquete LIFA. El objetivo global del proyecto es realizar la caracterización de luminarias LED, de forma que se obtengan medidas suficientes de la distribución de intensidad luminosa. Los datos se recogerán en un archivo fotométrico específico, siguiendo la normativa IESNA 2002 sobre formato de archivos fotométricos, que posteriormente será utilizado en la simulación y estudio de instalaciones reales de la luminaria. El sistema propuesto en este proyecto, es un sistema basado en fotometría tipo B, utilizando coordenadas VH, desarrollando un algoritmo de medida que la luminaria describa un ángulo de 180º en ambos ejes, con una resolución de 5º para el eje Vertical y 22.5º para el eje Horizontal, almacenando los datos en un array que será escrito en el formato exigido por la normativa. Una vez obtenidos los datos con el instrumento desarrollado, el fichero generado por la medida, es simulado con el software DIALux, obteniendo unas medidas de iluminación en la simulación que serán comparadas con las medidas reales, intentando reproducir en la simulación las condiciones reales de medida. ABSTRACT. The project involves the development of software for controlling the measurement of light intensity distribution in LEDs. In the course of the project theoretical foundations on basic photometry, of which the basic conditions for such action are extracted will be presented. Besides a brief description of the hardware used in the development of the machine, which is based on a Mega Arduino plate 2560 is made, that through the package Labview "LIFA" (Interface For Arduino Labview "), it is possible to use as data acquisition card by which to handle both sensors and actuators for control tasks. The instrument used in this project is the BTS256 of GigaHerzt-Optik house, which is available a development kit in both C ++ language as LabView, making it possible to program based on this software applications for any kind of adaptation to project needs. The software is developed in Labview 2013 platform, this is thanks to the availability of the SDK of the measuring instrument and the LIFA package. The overall objective of the project is the characterization of LED lights, so that sufficient measures the light intensity distribution are obtained. Data will be collected on a specific photometric file, following the rules IESNA 2002 on photometric format files, which will then be used in the simulation and study of actual installations of the luminaire. The proposed in this project is a system based on photometry type B system using VH coordinates, developing an algorithm as the fixture describe an angle of 180 ° in both axes, with a resolution of 5 ° to the vertical axis and 22.5º for the Horizontal axis, storing data in an array to be written in the format required by the regulations. After obtaining the data with the instrument developed, the file generated by the measure, is simulated with DIALux software, obtaining measures of lighting in the simulation will be compared with the actual measurements, trying to play in the simulation the actual measurement conditions .

Comparison of aggregation behaviors between branched and linear block polyethers: MesoDyn simulation study

The comparison of aggregation behaviors between the branched block polyether T1107 (polyether A) and linear polyether (EO)(60)(PO)(40)(EO)(60) (polyether B) in aqueous solution are investigated by the MesoDyn simulation. Polyether A forms micelles at lower concentration and has a smaller aggregation number than B. Both the polyethers show the time-dependent micellar growth behaviors. The spherical micelles appear and then change to rod-like micelles with time evolution in the 10 vol% solution of polyether A. The micellar cluster appears and changes to pseudo-spherical micelles with time evolution in the 20 vol% solution of polyether A. However, the spherical micelles appear and change to micellar cluster with time evolution in the 20 vol% polyether B solution. The shear can induce the micellar transition of both block polyethers. When the shear rate is 1x10(5) s(-1), the shear can induce the sphere-to-rod transition of both polyethers at the concentration of 10 and 20 vol%. When the shear rate is lower than 1x10(5) s(-1), the huge micelles and micellar clusters can be formed in the 10 and 20 vol% polyether A systems under the shear, while the huge micelles are formed and then disaggregated with the time evolution in the 20 vol% polyether B system.