2,194 research outputs found

    Stress Axis Hormones Induce Triglyceride Filled Nodule Formation in Vascular Smooth Muscle Cells

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    Homeostatic stress, such as that which occurs in diabetes, is associated with increased risk for the development of atherosclerosis. Atherosclerotic plaques of the artery wall are associated with both lipid accumulation and fibrous and/or calcified tissue accumulation. Vascular smooth muscle cells (VSMC) are derived from mesenchymal stem cells (MSC) which are capable of differentiating into adipocytes, chondrocytes and osteoblasts. MSC of the bone marrow are pushed toward the chondrogenic and adipogenic phenotypes in the presence of the stress hormones glucocorticoid and adrenocorticotropin (ACTH). This led us to hypothesize that the proliferative VSMC of the Goto-Kakizaki (GK) diabetic rat, when exposed to stress hormones will present an adipocytic and/or chondrogenic-like phenotype. VSMC of the GK rat were cultured using conditions that favor the multi-potential differentiation of MSC and were either left untreated, were treated with ACTH, dexamethasone (DEXA) or both. Cells were stained for lipid using oil-red-o, proteoglycan matrix using alcian blue and cell density using methylene blue. DEXA increased lipid nodule formation above the untreated control but the combined ACTH and DEXA treatment led to a significant increase above DEXA alone (lipid nodule #’s per field, DEXA 2.56 ± 1.63 vs. A+D 6.67 ± 1.68). These data suggest that stress hormones may contribute to VSMC matrix accumulation and lipid production during atherosclerosis development in diabetes

    Spillover and diffraction sidelobe contamination in a double-shielded experiment for mapping Galactic synchrotron emission

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    We have analyzed observations from a radioastronomical experiment to survey the sky at decimetric wavelengths along with feed pattern measurements in order to account for the level of ground contamination entering the sidelobes. A major asset of the experiment is the use of a wire mesh fence around the rim-halo shielded antenna with the purpose of levelling out and reducing this source of stray radiation for zenith-centered 1-rpm circular scans. We investigate the shielding performance of the experiment by means of a geometric diffraction model in order to predict the level of the spillover and diffraction sidelobes in the direction of the ground. Using 408 MHz and 1465 MHz feed measurements, the model shows how a weakly-diffracting and unshielded antenna configuration becomes strongly-diffracting and double-shielded as far-field diffraction effects give way to near-field ones. Due to the asymmetric response of the feeds, the orientation of their radiation fields with respect to the secondary must be known a priori before comparing model predictions with observational data. By adjusting the attenuation coefficient of the wire mesh the model is able to reproduce the amount of differential ground pick-up observed during test measurements at 1465 MHz.Comment: 14 pages, 17 eps + 1 gif figures and 4 Tables. Accepted for publication in A&AS. Fig.7 available at full resolution from http://www.das.inpe.br/~tello/publications.ht

    Numerical and analytical study of an atherosclerosis inflammatory disease model

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    We study a reaction–diffusion mathematical model for the evolution of atherosclerosis as an inflammation process by combining analytical tools with computer-intensive numerical calculations. The computational work involved the calculation of more than sixty thousand solutions of the full reaction–diffusion system and lead to the complete characterisation of the ωω-limit for every initial condition. Qualitative properties of the solution are rigorously proved, some of them hinted at by the numerical stud

    Orientaciones de meta en las clases de educación física : un análisis centrado en la educación secundaria obligatoria

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    This paper explores the subject of motivation in educational environments, more specifically in physical education. The research study it describes is based on the concept of goal perspectives (Nicholls, 1984, Dweck and Legget, 1988, Ames, 1984, Duda, 1992), and the purpose of the study was to identify the (task or ego) goal orientations shown by secondary school students in physical education classes, together with any possible differences based either on gender or the academic stage in the students education. The sample was composed of 203 secondary school students who all answered the POSQ questionnaire. From the results that were obtained, both goal orientations were observed, with a task-basedorientation predominating. It was also shown that boys are more ego oriented than girls

    Software-Defined architecture for QoS-Aware IoT deployments in 5G systems

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    [EN] Internet of Things (IoT), a ubiquitous network of interconnected objects, harvests information from the environments, interacts with the physical world, and uses the existing Internet infrastructure to provide services for information transfer and emerging applications. However, the scalability and Internet access fundamentally challenge the realization of a wide range of IoT applications. Based on recent developments of 5G system architecture, namely SoftAir, this paper introduces a new software-defined platform that enables dynamic and flexible infrastructure for 5G IoT communication. A corresponding sum-rate analysis is also carried out via an optimization approach for efficient data transmissions. First, the SoftAir decouples control plane and data plane for a software-defined wireless architecture and enables effective coordination among remote radio heads (RRHs), equipped with millimeter-wave (mmWave) frontend, for IoT access. Next, by introducing an innovative design of software-defined gateways (SD-GWs) as local IoT controllers in SoftAir, the wide diversity of IoT applications and the heterogeneity of IoT devices are easily accommodated. These SD-GWs aggregate the traffic from heterogeneous IoT devices and perform protocol conversions between IoT networks and radio access networks. Moreover, a cross-domain optimization framework is proposed in this extended SoftAir architecture concerning both upstream and downstream communication, where the respective sum-rates are maximized and system-level constraints are guaranteed, including (i) quality-of-service requirements of IoT transmissions, (ii) total power limit of mmWave RRHs, and (iii) fronthaul network capacities. Simulation results validate the efficacy of our solutions, where the extended SoftAir solution surpasses existing IoT schemes in spectral efficiency and achieves optimal data rates for next-generation IoT communication. (C) 2019 Elsevier B.V. All rights reserved.This work was supported by the US National Science Foundation (NSF) under Grant No. 1547353. A part of this work was supported by the Harry C. Kelly Memorial Fund, AC21 Special Project Fund (SPF), NC State 2019-2020 Internationalization Seed Grants and 2019 Faculty Research and Professional Development (FRPD) Program. The work of V. Pla was supported by Grant PGC2018-094151-B-I00 (MCIU/AEI/FEDER, UE).Tello-Oquendo, L.; Lin, S.; Akyildiz, IF.; Pla, V. (2019). Software-Defined architecture for QoS-Aware IoT deployments in 5G systems. Ad Hoc Networks. 93:1-11. https://doi.org/10.1016/j.adhoc.2019.101911S1119

    Treating hummingbirds as feathered bees : a case of ethological cross-pollination

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    Hummingbirds feed from hundreds of flowers every day. The properties of these flowers provide these birds with a wealth of information about colour, space and time to guide how they forage. To understand how hummingbirds might use this information, researchers have adapted established laboratory paradigms for use in the field. In recent years, however, experimental inspiration has come less from other birds, and more from looking at other nectar-feeders, particularly honeybees and bumblebees, which have been models for foraging behaviour and cognition for over a century. In a world in which the cognitive abilities of bees regularly make the news, research on the influence of ecology and sensory systems on bee behaviour is leading to novel insights in hummingbird cognition. As methods designed to study insects in the laboratory are being applied to hummingbirds in the field, converging methods can help us identify and understand convergence in cognition, behaviour and ecology.PostprintPeer reviewe
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