3,557 research outputs found

    Human peritoneal mesothelial cell death induced by high-glucose hypertonic solution involves Ca2+ and Na+ ions and oxidative stress with the participation of PKC/NOX2 and PI3K/Akt pathways

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    Indexación: Web of Science; Scopus.Chronic peritoneal dialysis (PD) therapy is equally efficient as hemodialysis while providing greater patient comfort and mobility. Therefore, PD is the treatment of choice for several types of renal patients. During PD, a high-glucose hyperosmotic (HGH) solution is administered into the peritoneal cavity to generate an osmotic gradient that promotes water and solutes transport from peritoneal blood to the dialysis solution. Unfortunately, PD has been associated with a loss of peritoneal viability and function through the generation of a severe inflammatory state that induces human peritoneal mesothelial cell (HPMC) death. Despite this deleterious effect, the precise molecular mechanism of HPMC death as induced by HGH solutions is far from being understood. Therefore, the aim of this study was to explore the pathways involved in HGH solution-induced HPMC death. HGH-induced HPMC death included influxes of intracellular Ca2+ and Na+. Furthermore, HGH-induced HPMC death was inhibited by antioxidant and reducing agents. In line with this, HPMC death was induced solely by increased oxidative stress. In addition to this, the cPKC/NOX2 and PI3K/Akt intracellular signaling pathways also participated in HGH-induced HPMC death. The participation of PI3K/Akt intracellular is in agreement with previously shown in rat PMC apoptosis. These findings contribute toward fully elucidating the underlying molecular mechanism mediating peritoneal mesothelial cell death induced by high-glucose solutions during peritoneal dialysis.https://www.frontiersin.org/articles/10.3389/fphys.2017.00379/ful

    A Grammar Compression Algorithm based on Induced Suffix Sorting

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    We introduce GCIS, a grammar compression algorithm based on the induced suffix sorting algorithm SAIS, introduced by Nong et al. in 2009. Our solution builds on the factorization performed by SAIS during suffix sorting. We construct a context-free grammar on the input string which can be further reduced into a shorter string by substituting each substring by its correspondent factor. The resulting grammar is encoded by exploring some redundancies, such as common prefixes between suffix rules, which are sorted according to SAIS framework. When compared to well-known compression tools such as Re-Pair and 7-zip, our algorithm is competitive and very effective at handling repetitive string regarding compression ratio, compression and decompression running time

    Runaway Futures, Technology, and the Collapse of Understanding in Times of Unprecedented Change: An Interview with Zoltán Boldizsár Simon

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    Simon ZB, Narita FZ. Runaway Futures, Technology, and the Collapse of Understanding in Times of Unprecedented Change: An Interview with Zoltán Boldizsár Simon. Transições. 2020;1(1):26-38

    Re-designing Dynamic Content Delivery in the Light of a Virtualized Infrastructure

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    We explore the opportunities and design options enabled by novel SDN and NFV technologies, by re-designing a dynamic Content Delivery Network (CDN) service. Our system, named MOSTO, provides performance levels comparable to that of a regular CDN, but does not require the deployment of a large distributed infrastructure. In the process of designing the system, we identify relevant functions that could be integrated in the future Internet infrastructure. Such functions greatly simplify the design and effectiveness of services such as MOSTO. We demonstrate our system using a mixture of simulation, emulation, testbed experiments and by realizing a proof-of-concept deployment in a planet-wide commercial cloud system.Comment: Extended version of the paper accepted for publication in JSAC special issue on Emerging Technologies in Software-Driven Communication - November 201

    Desarrollo de un sistema de informacion y control para los accesos del

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    96 p.La presente investigación aborda los resultados del desarrollo de un proyecto informático con el fin de crear un sistema de información y control del acceso de público de un club deportivo profesional. Con tal fin se plantea una solución informática a un problema de gestión de los asistentes a un espectáculo deportivo y también se identifica la inversión requerida y los posibles beneficios, así como su contribución a la mejora del manejo del volumen de socios y la situación económica de la institución

    Multiplicity in Early Stellar Evolution

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    Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and fragmentation of cloud cores, despite the inhibiting influence of magnetic fields. Surveys of Class 0 protostars with mm interferometers have revealed a very high multiplicity frequency of about 2/3, even though there are observational difficulties in resolving close protobinaries, thus supporting the possibility that all stars could be born in multiple systems. Near-infrared adaptive optics observations of Class I protostars show a lower binary frequency relative to the Class 0 phase, a declining trend that continues through the Class II/III stages to the field population. This loss of companions is a natural consequence of dynamical interplay in small multiple systems, leading to ejection of members. We discuss observational consequences of this dynamical evolution, and its influence on circumstellar disks, and we review the evolution of circumbinary disks and their role in defining binary mass ratios. Special attention is paid to eclipsing PMS binaries, which allow for observational tests of evolutionary models of early stellar evolution. Many stars are born in clusters and small groups, and we discuss how interactions in dense stellar environments can significantly alter the distribution of binary separations through dissolution of wider binaries. The binaries and multiples we find in the field are the survivors of these internal and external destructive processes, and we provide a detailed overview of the multiplicity statistics of the field, which form a boundary condition for all models of binary evolution. Finally we discuss various formation mechanisms for massive binaries, and the properties of massive trapezia.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

    Effect of dipolar interactions on the phase behavior of the Gay–Berne liquid crystal model

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    A computer simulation study of the phase behavior of the dipolar Gay–Berne liquid crystal model is presented. The phase transitions are determined with isothermal–isobaric ~NPT! Monte Carlo simulations, utilizing the reaction field method. The electrostatic forces are found to have a considerable effect on the nature of the observed phases, but the density at which the isotropic fluid becomes unstable with respect to partially ordered phases is seen to be remarkably insensitive to the strength of the dipole. We pay particular attention to the structure of the mesophases, combining information from several singlet and pair distribution functions to build up an accurate picture of the molecular arrangement of the systems

    Oxidative Stress in Disease and Aging: Mechanisms and Therapies 2016

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    International audienceOxidative stress (OS) is an imbalance between the formation of reactive oxygen species (ROS) and antioxidant defense mechanisms. This phenomenon increases with age and affects the normal functioning of several tissues. Furthermore, numerous chronic diseases associated with older age, such as diabetes and cardiovascular, renal, pulmonary, and skeletal muscle disorders, are also directly related to OS. Considering this relationship, the aim of many ongoing studies is to elucidate the underlying mechanisms and role of OS in disease onset and development. In particular, there is considerable emphasis on finding new therapeutic strategies for decreasing OS

    Dust Traps in the Protoplanetary Disk MWC 758: Two Vortices Produced by Two Giant Planets?

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    Resolved ALMA and VLA observations indicate the existence of two dust traps in the protoplanetary disc MWC 758. By means of two-dimensional gas+dust hydrodynamical simulations post-processed with three-dimensional dust radiative transfer calculations, we show that the spirals in scattered light, the eccentric, asymmetric ring and the crescent-shaped structure in the (sub)millimetre can all be caused by two giant planets: a 1.5-Jupiter mass planet at 35 au (inside the spirals) and a 5-Jupiter mass planet at 140 au (outside the spirals). The outer planet forms a dust-trapping vortex at the inner edge of its gap (at ∼85 au), and the continuum emission of this dust trap reproduces the ALMA and VLA observations well. The outer planet triggers several spiral arms that are similar to those observed in polarized scattered light. The inner planet also forms a vortex at the outer edge of its gap (at ∼50 au), but it decays faster than the vortex induced by the outer planet, as a result of the disc’s turbulent viscosity. The vortex decay can explain the eccentric inner ring seen with ALMA as well as the low signal and larger azimuthal spread of this dust trap in VLA observations. Finding the thermal and kinematic signatures of both giant planets could verify the proposed scenario
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