382 research outputs found
Interpreting the photometry and spectroscopy of directly imaged planets: a new atmospheric model applied to beta Pictoris b and SPHERE observations
We aim to interpret future photometric and spectral measurements from these
instruments, in terms of physical parameters of the planets, with an
atmospheric model using a minimal number of assumptions and parameters.
We developed Exoplanet Radiative-convective Equilibrium Model (Exo-REM) to
analyze the photometric and spectro- scopic data of directly imaged planets.
The input parameters are a planet's surface gravity (g), effective temperature
(Teff ), and elemental composition. The model predicts the equilibrium
temperature profile and mixing ratio profiles of the most important gases.
Opacity sources include the H2-He collision-induced absorption and molecular
lines from eight compounds (including CH4 updated with the Exomol line list).
Absorption by iron and silicate cloud particles is added above the expected
condensation levels with a fixed scale height and a given optical depth at some
reference wavelength. Scattering was not included at this stage.
We applied Exo-REM to photometric and spectral observations of the planet
beta Pictoris b obtained in a series of near-IR filters. We derived Teff = 1550
+- 150 K, log(g) = 3.5 +- 1, and radius R = 1.76 +- 0.24 RJup (2-{\sigma} error
bars from photometric measurements). These values are comparable to those found
in the literature, although with more conservative error bars, consistent with
the model accuracy. We were able to reproduce, within error bars, the J- and
H-band spectra of beta Pictoris b. We finally investigated the precision to
which the above parameterComment: 15 pages, 14 figures, accepted by A&
Deletion of periostin reduces muscular dystrophy and fibrosis in mice by modulating the transforming growth factor-β pathway
The muscular dystrophies are broadly classified as muscle wasting diseases with myofiber dropout due to cellular necrosis, inflammation, alterations in extracellular matrix composition, and fatty cell replacement. These events transpire and progress despite ongoing myofiber regeneration from endogenous satellite cells. The degeneration/regeneration response to muscle injury/disease is modulated by the proinflammatory cytokine transforming growth factor-β (TGF-β), which can also profoundly influence extracellular matrix composition through increased secretion of profibrotic proteins, such as the matricellular protein periostin. Here we show that up-regulation and secretion of periostin is pathological and enhances disease in the δ-sarcoglycan null (Sgcd(−/−)) mouse model of muscular dystrophy (MD). Indeed, MD mice lacking the Postn gene showed dramatic improvement in skeletal muscle structure and function. Mechanistically, Postn gene deletion altered TGF-β signaling so that it now enhanced tissue regeneration with reduced levels of fibrosis. Systemic antagonism of TGF-β with a neutralizing monoclonal antibody mitigated the beneficial effects of Postn deletion in vivo. These data suggest that periostin functions as a disease determinant in MD by promoting/allowing the pathological effects of TGF-β, suggesting that inhibition of periostin could represent a unique treatment approach
Granular components of cement: Influence of mixture composition
Raw granular materials used in cement manufacturing are limestone grains displaying a broad size distribution, ranging from microns to a couple of inches. They are stored as pyramidal heaps and, although empirical homogenization techniques are used with good results, there are important factors like segregation and grinding conditions that produce mixtures with different poorly controlled size. For this reason, the stability of the heaps strongly depends on these factors and it is important to study the influence of the respective amounts of particles of different sizes on the properties of the mixture. In this work, we report experiments analyzing the relationship between the characteristic angles of equilibrium of the heaps and the geometry, size and chemical composition of the grains. We also look for correlations between the values of the characteristic angles and the relative amounts of grains of different sizes that make up the materials. We demonstrate that the chemical composition is correlated with the geometry of the grains and that their aspect ratio does not influence the critical angles. We also show that the critical angles mostly depend on the relative amount of fine grains in the granular mixture and on the dispersion of the sizes. The results obtained allow one to draw conclusions that may be relevant to the treatment and storage of raw materials in the cement industry.Fil: Vidales, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Ippolito, Irene Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Grupo de Medios Porosos; ArgentinaFil: Benegas, Oscar Armando. Universidad Nacional de San Luis; ArgentinaFil: Aguirre, F.. Universidad Nacional de San Luis; ArgentinaFil: Nocera, O. C.. Universidad Nacional de San Luis; ArgentinaFil: Baudino, M. R.. Universidad Nacional de San Luis; Argentin
Optimized Antibacterial Effects in a Designed Mixture of Essential Oils of Myrtus communis, Artemisia herba-alba and Thymus serpyllum for Wide Range of Applications
Nowadays, the combination of molecules influences their biological effects, and interesting outcomes can be obtained from different component interactions. Using a mixture design method, this research seeks to simulate the efficacy of essential oil combinations against various bacteria and forecast the ideal combination. The chemical compositions of Myrtus communis, Artemisia herba-alba and Thymus serpyllum essential oils were analyzed using CG/MS. Then, the combined antibacterial effects were evaluated by testing mixture design formulations using the microdilution bioassay. The main compounds detected for M. communis essential oil were myrtenyl acetate (33.67%), linalool (19.77%) and 1,8-cineole (10.65%). A. herba-alba had piperitone as a chemotype, representing 85%. By contrast, the T. serpyllum oil contained thymol (17.29%), γ-terpinene (18.31%) and p-cymene (36.15%). The antibacterial effect of the essential oils studied, and the optimum mixtures obtained were target strain-dependent. T. serpyllum alone ensured the optimal inhibition against S. aureus and E. coli, while a ternary mixture consisting of 17.1%, 39.6% and 43.1% of M. communis, A. herba-alba and T. serpyllum respectively, was associated with optimal inhibitory activity against B. subtilis. The outcome of this research supports the idea of the boosting effect of essential oil combinations toward better activities, giving better understanding of the usefulness of mixture designs for food, cosmetics, and pharmaceutical applications
Optimized Antibacterial Effects in a Designed Mixture of Essential Oils of Myrtus communis, Artemisia herba-alba and Thymus serpyllum for Wide Range of Applications
Nowadays, the combination of molecules influences their biological effects, and interesting outcomes can be obtained from different component interactions. Using a mixture design method, this research seeks to simulate the efficacy of essential oil combinations against various bacteria and forecast the ideal combination. The chemical compositions of Myrtus communis, Artemisia herba-alba and Thymus serpyllum essential oils were analyzed using CG/MS. Then, the combined antibacterial effects were evaluated by testing mixture design formulations using the microdilution bioassay. The main compounds detected for M. communis essential oil were myrtenyl acetate (33.67%), linalool (19.77%) and 1,8-cineole (10.65%). A. herba-alba had piperitone as a chemotype, representing 85%. By contrast, the T. serpyllum oil contained thymol (17.29%), gamma-terpinene (18.31%) and p-cymene (36.15%). The antibacterial effect of the essential oils studied, and the optimum mixtures obtained were target strain-dependent. T. serpyllum alone ensured the optimal inhibition against S. aureus and E. coli, while a ternary mixture consisting of 17.1%, 39.6% and 43.1% of M. communis, A. herba-alba and T. serpyllum respectively, was associated with optimal inhibitory activity against B. subtilis. The outcome of this research supports the idea of the boosting effect of essential oil combinations toward better activities, giving better understanding of the usefulness of mixture designs for food, cosmetics, and pharmaceutical applications.Peer reviewe
Las intervenciones del investigador durante la entrevista clínica grupal : un análisis metodológico
Ponencia presentada en el X Encontro Nacional de Pesquisa em Educação em Ciências – X ENPEC
Águas de Lindóia, SP – 24 a 27 de Novembro de 2015.Las entrevistas grupales son una de las formas más usuales de indagación aceptadas en la comunidad de investigadores en Educación en Física. Las intervenciones del entrevistador no son azarosas sino que están ligadas a la agenda de investigación y constituyen además, una habilidad que el entrevistador desarrolla en sucesivas instancias de entrevista. En este estudio, analizamos las intervenciones de un entrevistador durante una tarea de resolución de problemas llevada a cabo por tres estudiantes. El objetivo es entender mejor cómo son las intervenciones del entrevistador y cómo, al mismo tiempo, logra que los estudiantes mantengan una actitud de indagación a la vez que progresa en su agenda de investigación. Los resultados muestran cómo dos tipos diferenciados de intervenciones, neutrales y perturbativas, se presentan a lo largo de la entrevista y cómo estos tipos de intervenciones se articulan con los procesos de aprendizaje conceptual, que son los que el entrevistador desea indagarGroup interviews are a very common practice within the Physics Education Research community. Although designed a priori, as they take place, the interviewer intervenes to probe some of the students’ lines of reasoning in a certain way. These interventions are not random, but rather guided by the research agenda at hand, and they represent the researcher’s expertise as such. In this study we analyze an interviewer’s interventions during a problem solving interview in which a group of students approach a problem solving task. The aim of our analysis is to better understand those interventions and how they are aligned with the need to keep students’ attitude as one of doing science, while progressing on the research agenda of the interviewer. Results show two distinct types of interventions: neutral an perturbative, and their analysis show how these articulate with the research agenda: that of obtaining data on students’ learning at a conceptual level.publishedVersionFil: Coleoni, Enrique A. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Coleoni, Enrique A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Buteler, Laura M. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Buteler, Laura M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Baudino Quiroga, Nicolás. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Baudino Quiroga, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Otras Ciencias de la Educació
Triglyceride-Rich Lipoproteins Modulate the Distribution and Extravasation of Ly6C/Gr1low Monocytes
Monocytes are heterogeneous effector cells involved in the maintenance and restoration of tissue integrity. However, their response to hyperlipidemia remains poorly understood. Here, we report that in the presence of elevated levels of triglyceride-rich lipoproteins, induced by administration of poloxamer 407, the blood numbers of non-classical Ly6C/Gr1(low) monocytes drop, while the number of bone marrow progenitors remains similar. We observed an increased crawling and retention of the Gr1(low) monocytes at the endothelial interface and a marked accumulation of CD68(+) macrophages in several organs. Hypertriglyceridemia was accompanied by an increased expression of tissue, and plasma CCL4 and blood Gr1(low) monocyte depletion involved a pertussis-toxin-sensitive receptor axis. Collectively, these findings demonstrate that a triglyceride-rich environment can alter blood monocyte distribution, promoting the extravasation of Gr1(low) cells. The behavior of these cells in response to dyslipidemia highlights the significant impact that high levels of triglyceride-rich lipoproteins may have on innate immune cells
Optimized Antibacterial Effects in a Designed Mixture of Essential Oils of Myrtus communis, Artemisia herba-alba and Thymus serpyllum for Wide Range of Applications
Nowadays, the combination of molecules influences their biological effects, and interesting outcomes can be obtained from different component interactions. Using a mixture design method, this research seeks to simulate the efficacy of essential oil combinations against various bacteria and forecast the ideal combination. The chemical compositions of Myrtus communis, Artemisia herba-alba and Thymus serpyllum essential oils were analyzed using CG/MS. Then, the combined antibacterial effects were evaluated by testing mixture design formulations using the microdilution bioassay. The main compounds detected for M. communis essential oil were myrtenyl acetate (33.67%), linalool (19.77%) and 1,8-cineole (10.65%). A. herba-alba had piperitone as a chemotype, representing 85%. By contrast, the T. serpyllum oil contained thymol (17.29%), γ-terpinene (18.31%) and p-cymene (36.15%). The antibacterial effect of the essential oils studied, and the optimum mixtures obtained were target strain-dependent. T. serpyllum alone ensured the optimal inhibition against S. aureus and E. coli, while a ternary mixture consisting of 17.1%, 39.6% and 43.1% of M. communis, A. herba-alba and T. serpyllum respectively, was associated with optimal inhibitory activity against B. subtilis. The outcome of this research supports the idea of the boosting effect of essential oil combinations toward better activities, giving better understanding of the usefulness of mixture designs for food, cosmetics, and pharmaceutical applications
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