13,140 research outputs found

    A Multifrequency Analysis of the Polarized Diffuse Galactic Radio Emission at Degree Scales

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    The polarized diffuse Galactic radio emission, mainly synchrotron emission, is expected to be one of the most relevant source of astrophysical contamination at low and moderate multipoles in cosmic microwave background polarization anisotropy experiments at frequencies lower then 50 to 100 GHz. We present here preliminary results based on a recent analysis of the Leiden surveys covering about 50% of the sky at low as well as at middle and high Galactic latitudes. By implementing specific interpolation methods to deal with these data, which show a large variation of the sampling across the sky, we produce maps of the polarized diffuse Galactic synchrotron component at frequencies between 408 and 1411 MHz with pixel sizes larger or equal to about 0.92 degrees. We derive the angular power spectrum of this component for the whole covered region and for three patches in the sky significantly oversampled with respect to the average and at different Galactic latitudes. We find multipole spectral indices typically ranging between about -3 and about -1, according to the considered frequency and sky region. At frequencies higher or equal to 610 MHz, the frequency spectral indices observed in the considered sky regions are about -3.5, compatible with an intrinsic frequency spectral index of about -5.8 and a depolarization due to Faraday rotation with a rotation measure RM of about 15 radians per square meter. This implies that the observed angular power spectrum of the polarized signal is about 85% or 20% of the intrinsic one at 1411 MHz or 820 MHz respectively.Comment: 6 pages, 5 figures. to appear in S.Cecchini et al., Astrophysical Polarized Backgrounds, AIP Conf. Proceeding

    Protein accumulation in the endoplasmic reticulum as a non-equilibrium phase transition

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    Several neurological disorders are associated with the aggregation of aberrant proteins, often localized in intracellular organelles such as the endoplasmic reticulum. Here we study protein aggregation kinetics by mean-field reactions and three dimensional Monte carlo simulations of diffusion-limited aggregation of linear polymers in a confined space, representing the endoplasmic reticulum. By tuning the rates of protein production and degradation, we show that the system undergoes a non-equilibrium phase transition from a physiological phase with little or no polymer accumulation to a pathological phase characterized by persistent polymerization. A combination of external factors accumulating during the lifetime of a patient can thus slightly modify the phase transition control parameters, tipping the balance from a long symptomless lag phase to an accelerated pathological development. The model can be successfully used to interpret experimental data on amyloid-\b{eta} clearance from the central nervous system

    The forward kinematics of doubly-planar Gough-Stewart platforms and the position analysis of strips of tetrahedra

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    The final publication is available at link.springer.comA strip of tetrahedra is a tetrahedron-tetrahedron truss where any tetrahedron has two neighbors except those in the extremes which have only one. The problem of finding all the possible lengths for an edge in the strip compatible with a given distance imposed between the strip end-points has been revealed of relevance due to the large number of possible applications. In this paper, this is applied to solve the forward kinematics of 6-6 Gough-Stewart platforms with planar base and moving platform, a problem which is known to have up to 40 solutions (20 if we do not consider mirror configurations with respect to the base as different solutions).Peer ReviewedPostprint (author's final draft

    Protein Crosslinks Influence Food Digestion

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    Enzymatic crosslinking is increasingly applied to confer specific properties to different proteins and, consequently, to food products of which they are components. Among the most investigated enzymes, transglutaminases (in particular the microbial isoform, mTG) and various oxidative biocatalysts are having special attention by food biotechnology researchers. mTG catalyzes isopeptide bond formation among protein molecules, leading to inter-molecular crosslinks and being able to produce both homo- and hetero-polymers. Its peculiar properties, such as the calcium independency, the broad substrate specificity, the stability over a wide range of temperatures and pH values, make such enzyme an effective tool to modify the characteristics of many protein-based foods

    Legal determinants of external finance revisited : the inverse relationship between investor protection and societal well-being

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    This paper investigates relationships between corporate governance traditions and quality of life as measured by a number of widely reported indicators. It provides an empirical analysis of indicators of societal health in developed economies using a classification based on legal traditions. Arguably the most widely cited work in the corporate governance literature has been the collection of papers by La Porta et al. which has shown, inter alia, statistically significant relationships between legal traditions and various proxies for investor protection. We show statistically significant relationships between legal traditions and various proxies for societal health. Our comparative evidence suggests that the interests of investors may not be congruent with the interests of wider society, and that the criteria for judging the effectiveness of approaches to corporate governance should not be restricted to financial metrics

    Transaminases persistentemente elevadas - o que fazer?

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    The persistent hypertransaminasemia requires detailed clinical analyses with history, physical examination and laboratory tests for liver evaluation and differential diagnosis. The purpose of this article is to assist the pediatrician in the management of these cases to optimize the invetigation and diagnosis of these patients. The values of these enzymes can vary according to age group and may be the first manifestation of a liver disease, or metabolic, genetic or extrahepatic disease

    Beyond ras and braf: Her2, a new actionable oncotarget in advanced colorectal cancer

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    The human epidermal growth factor receptor 2 (HER2) is a well-established oncogenic driver and a successful therapeutic target in several malignancies, such as breast and gastric cancers. HER2 alterations, including amplification and somatic mutations, have also been detected in a small but not negligible subset of patients affected by advanced colorectal cancer (aCRC). However, to date, there are no available oncotargets in this malignancy beyond RAS and BRAF that are available. Here we present an overview on the present predictive and prognostic role of HER2 expression in aCRC, as well as on its consequent potential therapeutic implications from preclinical investigations towards ongoing trials testing anti-HER2 agents in aCRC. While HER2â€Č s role as a molecular predictive biomarker for anti-EGFR therapies in CRC is recognized, HER2 prognostic value remains controversial. Moreover, thanks to the impressive and growing body of clinical evidence, HER2 is strongly emerging as a new potential actionable oncotarget in aCRC. In conclusion, in the foreseeable future, HER2-targeted therapeutic strategies may integrate the algorithm of aCRC treatment towards an increasingly tailored therapeutic approach to this disease

    Effects of creatine treatment on Jejunal phenotypes in a rat model of acidosis

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    We investigated the effects of creatine treatment on jejunal phenotypes in a rat model of oxidative stress induced by acidosis. In particular, the activities of some antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase), the level of lipid peroxidation, the expression of heat shock proteins (HSP70), and the expression of the major carriers of the cells (Na+/K+-ATPase, sodium-glucose Transporter 1\u2014SGLT1, and glucose transporter 2\u2014GLUT2) were measured under control and chronic acidosis conditions. Creatine did not affect the activity of antioxidant enzymes in either the control or acidosis groups, except for catalase, for which the activity was reduced in both conditions. Creatine did not change the lipid peroxidation level or HSP70 expression. Finally, creatine stimulated (Na+/K+)-ATPase expression under both control and chronic acidosis conditions. Chronic acidosis caused reductions in the expression levels of GLUT2 and SGLT1. GLUT2 reduction was abolished by creatine, while the presence of creatine did not induce any strengthening effect on the expression of SGLT1 in either the control or chronic acidosis groups. These results indicate that creatine has antioxidant properties that are realized through direct interaction of the molecule with reactive oxygen species. Moreover, the administration of creatine seems to determine a functional strengthening of the tissue, making it more resistant to acidosis

    IndicaçÔes e contra-indicaçÔes no transplante hepåtico pediåtrico

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    Advances in cirurgical techniques and immunessupressores result in better prognosis of patients elected to pediatric liver transplant. Many questions still arise as the transplant indications. Notes that in childhood the liver failure can occur faster than in adults. The main symptons are: progressive cholestasis, encephalopathy, ascites, bleeding of esophageal varices, Hepatopulmonary syndrome, malnutrition, recurrent infections, liver dysfunction, disabling itching and delayed growth and development
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