3,184 research outputs found

    Evaluation of 2.1µm DFB lasers for space applications

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    This paper presents the results obtained in the frame of an ESA-funded project called “Screening and Preevaluation of Shortwave Infrared Laser Diode for Space Application” with the objective of verifying the maturity of state of the art SWIR DFB lasers at 2.1µm to be used for space applications (mainly based on the occultation measurement principle and spectroscopy). The paper focus on the functional and environmental evaluation test plan. It includes high precision characterization, mechanical test (vibration and SRS shocks), thermal cycling, gamma and proton radiation tests, life test and some details of the Destructive Physical Analysis performed. The electro-optical characterization includes measurements of the tuning capabilities of the laser both by current and by temperature, the wavelength stability and the optical power versus laser current

    From voice to knowledge: A proposal for a voice annotation system to support collaborative engineering design processes

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    This paper describes a novel voice interaction mechanism for capturing and managing design knowledge within a collaborative Computer-Aided Design (CAD) environment. We present a software module for speech recognition that integrates with a CAD application to allow the automatic creation of textual annotations in a 3D model directly from voice data. Audio is transcribed automatically, resulting in a textual note that is searchable and available to other users via a Product Data Management (PDM) system, providing an intuitive mechanism to document modeling processes and design knowledge. The system consists of three functional blocks: (1) audio recording, (2) speech recognition, and (3) query management against a cloud-based service. In this paper, we justify the need for our system from a human-computer interaction standpoint and discuss the rationale of its design and implementation in the context of collaborative design communication. Finally, we discuss some application spaces that demonstrate the capability of voice annotations for capturing knowledge

    1.3 mm Polarized emission in the circumstellar disk of a massive protostar

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    We present the first resolved observations of the 1.3 mm polarized emission from the disk-like structure surrounding the high-mass protostar Cepheus A HW2. These CARMA data partially resolve the dust polarization, suggesting a uniform morphology of polarization vectors with an average position angle of 57° ± 6° and an average polarization fraction of 2.0% ± 0.4%. The distribution of the polarization vectors can be attributed to (1) the direct emission of magnetically aligned grains of dust by a uniform magnetic field, or (2) the pattern produced by the scattering of an inclined disk. We show that both models can explain the observations, and perhaps a combination of the two mechanisms produces the polarized emission. A third model including a toroidal magnetic field does not match the observations. Assuming scattering is the polarization mechanism, these observations suggest that during the first few 104 years of high-mass star formation, grain sizes can grow from1 mm to several 10s μm.Fil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; ArgentinaFil: Stephens, I. W.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos. Boston University; Estados Unidos. University of Illinois; Estados UnidosFil: Girart, J. M.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos. Institut de Ciències de l’Espai; EspañaFil: Looney, L.. University of Illinois; Estados UnidosFil: Curiel, S.. Universidad Nacional Autónoma de México; MéxicoFil: Segura Cox, D.. University of Illinois; Estados UnidosFil: Eswaraiah, C.. National Tsing Hua University; República de ChinaFil: Lai, S. P.. National Tsing Hua University; República de Chin

    Characterization of HIV-1 RNA forms in the plasma of patients undergoing successful HAART

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    An assay to characterize plasma human immunodeficiency virus 1 (HIV-1) sequences for patients with low viral loads was developed by combining the selective binding of anti-CD44 MicroBeads with a nested RT-PCR targeting the env C2V4 region. Sequences were obtained from 10 of 20 HIV+ patients who had viral loads below 48 copies/ml. Sequences derived from plasma were compared to those from CD14+ CD16 +monocytes and CD4+ T cells. The plasma sequences were most closely related to those amplified from monocytes, suggesting that during successful antiretroviral therapy, the predominant plasma virus originates from myeloid cells. By characterizing HIV-1 RNA sequences from 8 ml of plasma while avoiding multiple steps, which can lead to contamination and deterioration, this method can help elucidate the viral forms in patients with therapeutically suppressed HIV-1. Understanding the source of residual viremia is crucial in developing approaches for viral eradication

    Neuronal and epithelial cell rescue resolves chronic systemic inflammation in the lipid storage disorder Niemann-Pick C

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    Chronic systemic inflammation is thought to be a major contributor to metabolic and neurodegenerative diseases. Since inflammatory components are shared among different disorders, targeting inflammation is an attractive option for mitigating disease. To test the significance of inflammation in the lipid storage disorder (LSD) Niemann-Pick C (NPC), we deleted the macrophage inflammatory gene Mip1a/Ccl3 from NPC diseased mice. Deletion of Ccl3 had been reported to delay neuronal loss in Sandhoff LSD mice by inhibiting macrophage infiltration. For NPC mice, in contrast, deleting Ccl3 did not retard neurodegeneration and worsened the clinical outcome. Depletion of visceral tissue macrophages also did not alter central nervous system (CNS) pathology and instead increased liver injury, suggesting a limited macrophage infiltration response into the CNS and a beneficial role of macrophage activity in visceral tissue. Prevention of neuron loss or liver injury, even at late stages in the disease, was achieved through specific rescue of NPC disease in neurons or in liver epithelial cells, respectively. Local epithelial cell correction was also sufficient to reduce the macrophage-associated pathology in lung tissue. These results demonstrate that elevated inflammation and macrophage activity does not necessarily contribute to neurodegeneration and tissue injury, and LSD defects in immune cells may not preclude an appropriate inflammatory response. We conclude that inflammation remains secondary to neuronal and epithelial cell dysfunction and does not irreversibly contribute to the pathogenic cascade in NPC disease. Without further exploration of possible beneficial roles of inflammatory mediators, targeting inflammation may not be therapeutically effective at ameliorating disease severity

    Relatively low-temperature processing and its impact on device performance and reliability

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    Non-silicon, large-area/flexible electronics for the internet of things (IoT) has acquired substantial attention in recent years. Key electron devices to enable this technology include metal-oxide-semiconductor field effect transistors (MOSFETs), where ultra-thin and/or low-dimensional (i.e., 2D to a few layers) semiconductor materials may be required, like those found in thin-film transistors (TFTs) and transition metal dichalcogenide (TMD) FETs [1,2]. Whether TFT or TMDFET, a relatively low-temperature process commensurate with large-area/flex applications to enable large (i.e., greater than 300 mm) and/or flexible substrate fabrication is required. Furthermore, TMD materials may be implemented as the channel semiconductor to function as an ultra-thin body to mitigate short channel effects and extend further scaling as the future progresses in CMOS scaling. In addition, the gate dielectric insulator is another vital component of any MOSFET that requires investigation as part of the MOS stack in these types of transistors. Lastly, semiconductor materials mentioned herein do not have a universally accepted way to introduce dopants to form sources and drains. Thus, metal-semiconductor contacts are employed where the interface region of the contact plays a critical role in determining the conductivity/resistivity of the contact. Moreover, how the metal-semiconductor interface are formed also impacts the quality of the contact. Therefore, exploration of low-temperature processing, interfaces, and their impact on device performance and reliability will be critical to eventual implementation in future technologies. To ascertain the impact of low-temperature fabrication and critical interfaces, several process approaches and electrical characterization methods were employed [1-6]. In one case, for a TMD FET contact study, an oxygen plasma exposure in the contact region on MoS2 (a TMD material) is done prior to titanium deposition. The results demonstrate that contaminants and photoresist residue that still reside after development can noticeably impact electrical performance (Fig. 1). The O2 plasma removes the residue present at the surface of MoS2 without the use of a high temperature anneal, and subsequently improves the device performance significantly (Fig. 1) [1]. In another case, for a MOS-based TFT study, an investigation of low-temperature (\u3e 115°C) deposited zinc-based semiconductors was executed (Fig. 2). For ZnO and IGZO, saturation mobilities of 14.4 and 8.4 cm2/V-s, along with threshold voltages of 2.2 V and 2.0 V were obtained, respectively, demonstrating robust devices that also have an on/off ratio \u3e 108, with IOFF lower than 10-12 A. Furthermore, a hot carrier stress methodology demonstrated threshold voltage (VTH) shifts of 0.4 V and 1.8 V for ZnO and IGZO, respectively, after stress (Fig. 2) [2]. Continued research is required to ascertain the electrically active defects responsible for the VTH shift. Please click Additional Files below to see the full abstract

    IFE Plant Technology Overview and contribution to HiPER proposal

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    HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here

    Associations of sNfL with clinico-radiological measures in a large MS population

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    Esclerosi múltiple; Cadena lleugera de neurofilaments sèricsEsclerosis múltiple; Cadena ligera de neurofilamentos séricosMultiple sclerosis; Serum neurofilament light chainObjective Evaluation of serum neurofilament light chain (sNfL), measured using high-throughput assays on widely accessible platforms in large, real-world MS populations, is a critical step for sNfL to be utilized in clinical practice. Methods Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) is a network of healthcare institutions in the United States and Europe collecting standardized clinical/imaging data and biospecimens during routine clinic visits. sNfL was measured in 6974 MS and 201 healthy control (HC) participants, using a high-throughput, scalable immunoassay. Results Elevated sNfL levels for age (sNfL-E) were found in 1238 MS participants (17.8%). Factors associated with sNfL-E included male sex, younger age, progressive disease subtype, diabetes mellitus, impaired renal function, and active smoking. Higher body mass index (BMI) was associated with lower odds of elevated sNfL. Active treatment with disease-modifying therapy was associated with lower odds of sNfL-E. MS participants with sNfL-E exhibited worse neurological function (patient-reported disability, walking speed, manual dexterity, and cognitive processing speed), lower brain parenchymal fraction, and higher T2 lesion volume. Longitudinal analyses revealed accelerated short-term rates of whole brain atrophy in sNfL-E participants and higher odds of new T2 lesion development, although both MS participants with or without sNfL-E exhibited faster rates of whole brain atrophy compared to HC. Findings were consistent in analyses examining age-normative sNfL Z-scores as a continuous variable. Interpretation Elevated sNfL is associated with clinical disability, inflammatory disease activity, and whole brain atrophy in MS, but interpretation needs to account for comorbidities including impaired renal function, diabetes, and smoking.Study funding was provided from the National Institutes of Health (K23NS117883 to E.S.S.; K01MH121582 to K.C.F.; U01NS111678 to P.A.C.), National Multiple Sclerosis Society (RG-1904-33834 to E.S.S.; RG-1904-33800 to P.A.C.), and Biogen
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