187 research outputs found

    Space Qualification Issues in Acousto-optic and Electro-optic Devices

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    Satellite and space-based applications of photonic devices and systems require operational reliability in the harsh environment of space for extended periods of time. This in turn requires every component of the systems and their packaging to meet space qualifications. Acousto- and electro-optical devices form the major components of many current space based optical systems, which is the focus of this paper. The major space qualification issues are related to: mechanical stability, thermal effects and operation of the devices in the naturally occurring space radiation environment. This paper will discuss acousto- and electro-optic materials and devices with respect to their stability against mechanical vibrations, thermal cycling in operating and non-operating conditions and device responses to space ionizing and displacement radiation effects. Selection of suitable materials and packaging to meet space qualification criteria will also be discussed. Finally, a general roadmap for production and testing of acousto- and electro-optic devices will be discussed

    Polymer-based paclitaxel-eluting stents reduce in-stent neointimal tissue proliferation A serial volumetric intravascular ultrasound analysis from the TAXUS-IV trial

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    ObjectivesThe aim of this study was to use serial volumetric intravascular ultrasound (IVUS) to evaluate the effects of polymer-based, paclitaxel-eluting stents on in-stent neointima formation and late incomplete stent apposition.BackgroundThe TAXUS-IV trial demonstrated that the slow-release, polymer-based, paclitaxel-eluting stent reduces angiographic restenosis and the need for repeat revascularization procedures. Serial IVUS studies reveal details of the pattern of vascular responses provoked by stent implantation that provide insight into device safety and efficacy.MethodsIn the TAXUS-IV trial, patients were randomized to the slow-release, polymer-based, paclitaxel-eluting TAXUS stent or a bare-metal EXPRESS stent (Boston Scientific Corp., Natick, Massachusetts). As part of a formal substudy, complete volumetric IVUS data were available in 170 patients, including 88 TAXUS patients and 82 controls, at implantation and at nine-month follow-up.ResultsNo baseline differences were present in the clinical characteristics or IVUS parameters between the control and TAXUS groups. At nine-month follow-up, IVUS lumen volumes were larger in the TAXUS group (123 ± 43 mm3vs. 104 ± 44 mm3, p = 0.005), due to a reduction in neointimal volume (18 ± 18 mm3vs. 41 ± 23 mm3, p < 0.001). Millimeter-by-millimeter analysis within the stent demonstrated uniform suppression of neointimal growth along the entire stent length. Late lumen loss was similar at the proximal edge of the stent between the two groups, and reduced with the TAXUS stent at the distal edge (p = 0.004). Incomplete stent apposition at nine months was observed in only 3.0% of control and 4.0% of TAXUS stents (p = 0.12).ConclusionsPolymer-based, paclitaxel-eluting TAXUS stents are effective in inhibiting neointimal tissue proliferation, and do not result in late incomplete stent apposition

    The Concussion Recognition Tool 5th Edition (CRT5): Background and rationale

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    The Concussion Recognition Tool 5 (CRT5) is the most recent revision of the Pocket Sport Concussion Assessment Tool 2 that was initially introduced by the Concussion in Sport Group in 2005. The CRT5 is designed to assist non-medically trained individuals to recognise the signs and symptoms of possible sport-related concussion and provides guidance for removing an athlete from play/sport and to seek medical attention. This paper presents the development of the CRT5 and highlights the differences between the CRT5 and prior versions of the instrument

    Diversidade de resultados no estudo do transtorno de déficit de atenção e hiperatividade

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    Com este artigo pretende-se abordar a problemática da diversidade de dados na investigação do Transtorno de Déficit de Atenção e Hiperatividade (TDAH). Apresenta-se uma revisão da literatura centrada na heterogeneidade de conclusões relativas à caracterização do transtorno, à distinção dos subtipos, aos contextos de informação, às diferenças de gênero e à comorbidade. Na tentativa de compreender a disparidade de conclusões, salientam-se potenciais fatores explicativos, nomeadamente a heterogeneidade das amostras, a diversidade de metodologias e de procedimentos de investigação, entre outros.With this paper we aimed at addressing the problem of data diversity in Attention-Deficit Hyperactivity Disorder (ADHD) research. We present a literature review based on the heterogeneity of findings about the characterization of the disorder, subtypes differentiation, sources of information, sex differences and comorbidities. In an effort to understand the variety of findings, we underline potential explanations, such as the sample’s heterogeneity or the multiplicity of methods and procedures, among others.(undefined
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