779 research outputs found

    Deep Submicron III-V on Si-Based Esaki Diode

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    Esaki tunneling diodes are reemerging as a viable technology option in helping to improve speed and performance of many high speed device applications. The revival of this technology may be linked to the development of new substrates available to research that allows for the fabrication of a device comparable to current silicon technology. Using a 111-V on Silicon Substrate, it was demonstrated that it is possible to create working Esaki Tunneling Diodes

    Susceptibilidad de Anopheles albimanus a los insecticidas en cuatro localidades de Tumbes

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    El control de los vectores de importancia médica ha sido parte vital en la estrategia global para el control de los mosquitos involucrados en la transmisión de enfermedades, y la aplicación de insecticidas representa la medida de intervención práctica más importante y utilizada para reducir las enfermedades transmitidas por estos insectos vectores (Casabé et al.,1988). Sin embargo, en la actualidad, el incremento considerable de las enfermedades transmitidas por mosquitos ha originado un grave problema de salud pública, debido en parte al desarrollo de resistencia a los insecticidas en las poblaciones de mosquitos (Hemingway et al., 2004; Liu et al., 2004) y de resistencia de los parásitos a los medicamentos antipalúdicos (Phillips, 2001; Hemingway et al., 2002). La Organización Mundial de la Salud (OMS) define la resistencia como una característica heredada que otorga una mayor tolerancia a un plaguicida o grupo de plaguicida, de tal modo que los individuos resistentes sobreviven a una concentración del compuesto (o compuestos) que normalmente sería mortal para la especie (OMS,1992)

    Sonar-induced pressure fields in a post-mortem common dolphin

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    Author Posting. © Acoustical Society of America, 2012. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 131 (2012): 1595-1604, doi:10.1121/1.3675005.Potential physical effects of sonar transmissions on marine mammals were investigated by measuring pressure fields induced in a 119-kg, 211-cm-long, young adult male common dolphin (Delphinus delphis) cadaver. The specimen was instrumented with tourmaline acoustic pressure gauges used as receiving sensors. Gauge implantation near critical tissues was guided by intraoperative, high-resolution, computerized tomography (CT) scanning. Instrumented structures included the melon, nares, ear, thoracic wall, lungs, epaxial muscle, and lower abdomen. The specimen was suspended from a frame equipped with a standard 50.8-mm-diameter spherical transducer used as the acoustic source and additional receiving sensors to monitor the transmitted and external, scattered field. Following immersion, the transducer transmitted pulsed sinusoidal signals at 5, 7, and 10 kHz. Quantitative internal pressure fields are reported for all cases except those in which the gauge failed or no received signal was detected. A full necropsy was performed immediately after the experiment to examine instrumented areas and all major organs. No lesions attributable to acoustic transmissions were found, consistent with the low source level and source-receiver distances.Work supported by NOPP through ONR Grant No. N000140710992. Work at CSI additionally supported by ONR Grant No. N000140811231

    Determination of the pharmacokinetics and oral bioavailability of salicylamine, a potent γ-ketoaldehyde scavenger, by LC/MS/MS

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    Levels of reactive γ-ketoaldehydes derived from arachidonate increase in diseases associated with inflammation and oxidative injury. To assess the biological importance of these γ-ketoaldehydes, we previously identified salicylamine as an effective γ-ketoaldehyde scavenger in vitro and in cells. To determine if salicylamine could be administered in vivo, we developed an LC/MS/MS assay to measure salicylamine in plasma and tissues. In mice, half-life (t1/2) was 62 minutes. Drinking water supplementation (1-10 g/L) generated tissue concentrations (10-500 μM) within the range previously shown to inhibit γ-ketoaldehydes in cells. Therefore, oral administration of salicylamine can be used to assess the contribution of γ-ketoaldehydes in animal models of disease. © 2010 by the authors licensee Molecular Diversity Preservation International, Basel, Switzerland

    Sensing Molecules with Metal–Organic Framework Functionalized Graphene Transistors

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    Graphene is inherently sensitive to vicinal dielectrics and local charge distributions, a property that can be probed by the position of the Dirac point in graphene field-effect transistors. Exploiting this as a useful sensing principle requires selectivity; however, graphene itself exhibits no molecule-specific interaction. Complementarily, metal–organic frameworks can be tailored to selective adsorption of specific molecular species. Here, a selective ethanol sensor is demonstrated by growing a surface-mounted metal–organic framework (SURMOF) directly onto graphene field-effect transistors (GFETs). Unprecedented shifts of the Dirac point, as large as 15 V, are observed when the SURMOF/GFET is exposed to ethanol, while a vanishingly small response is observed for isopropanol, methanol, and other constituents of the air, including water. The synthesis and conditioning of the hybrid materials sensor with its functional characteristics are described and a model is proposed to explain the origin, magnitude, and direction of the Dirac point voltage shift. Tailoring multiple SURMOFs to adsorb specific gases on an array of such devices thus generates a versatile, selective, and highly sensitive platform for sensing applications

    An eHealth-Care Driven Perspective on 5G Networks and Infrastructure

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    This work describes the advancements that next generation mobile networks can bring to emergency services on the basis of a fully 5G enabled medical emergency response scenario. An ambulance service combining autonomous driving, advanced on-board patient monitoring, remote diagnosis and remote control from the hospital is introduced, allowing increased levels of care during patient transport and improved early diagnosis, thus enhancing patient survival rates. Furthermore, it is shown that such an ambulance service requires a variety of different traffic types that can only be supported concurrently and with guaranteed quality of service by a high-performance network fulfilling all 5G key performance indicators. The scenario described combines a multitude of aspects and applications enabled by 5G mobile communications, including autonomous driving, ultra-high definition video streaming, tactile remote interaction and continuous sensing, into a compelling showcase for a 5G enabled future. A centralized radio access 5G network with space division multiplexed optical fronthaul using analog radio-over-fiber and optical beamforming is analyzed, fully supporting SDN and NFV for advanced network slicing and quality of service guarantee.</p

    Party system closure and openness: conceptualization, operationalization and validation

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    The degree of closure of the governmental arena is a central aspect of the stabilization of party systems, and yet little systematic effort has been devoted to its operationalization. The article proposes a new index, examines its reliability and validity, and reports the ranking of 60 party systems. By redefining the units of measurement we suggest new indicators that are uniform and transparent in their logic of construction, can be applied both to specific government-changes and to time periods, and are sensitive to the degree of change. The article finds a hierarchy among the components of party system closure, dominated by coalition formula. While new and established democracies can both produced closed patterns, the analysis of inter-war European party systems shows that closed systems are less prone to authoritarian takeover. The article demonstrates the power of inertia: the completely closed configurations stand out as the most durable ones

    Efficient differentiation of Corynebacterium striatum, Corynebacterium amycolatum and Corynebacterium xerosis clinical isolates by multiplex PCR using novel species-specific primers

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    A multiplex-PCR (mPCR) assay was designed with species-specific primers which generate amplicons of 226 bp, 434 bp and 106 bp for differentiating the species C. striatum, C. amycolatum, and C. xerosis, respectively. mPCR results were 100% in agreement with identifications achieved by 16S rRNA and rpoB gene sequencing and by VITEK-MS.This work was supported by grants from FAPESB (JCB0031/2013) and CAPES (PROCAD 071/2013)

    Trans-endocytosis of CD80 and CD86:a molecular basis for the cell-extrinsic function of CTLA-4

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    Cytotoxic T lymphocyte antigen 4 (CTLA-4) is an essential negative regulator of T cell immune responses whose mechanism of action is the subject of debate. CTLA-4 shares two ligands (CD80 and CD86) with a stimulatory receptor, CD28. Here, we show that CTLA-4 can capture its ligands from opposing cells by a process of trans-endocytosis. After removal, these costimulatory ligands are degraded inside CTLA-4-expressing cells, resulting in impaired costimulation via CD28. Acquisition of CD86 from antigen-presenting cells is stimulated by T cell receptor engagement and observed in vitro and in vivo. These data reveal a mechanism of immune regulation in which CTLA-4 acts as an effector molecule to inhibit CD28 costimulation by the cell-extrinsic depletion of ligands, accounting for many of the known features of the CD28-CTLA-4 system
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