26 research outputs found

    Secondary crystalline phases identification in Cu2ZnSnSe4 thin films: contributions from Raman scattering and photoluminescence

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    In this work, we present the Raman peak positions of the quaternary pure selenide compound Cu2ZnSnSe4 (CZTSe) and related secondary phases that were grown and studied under the same conditions. A vast discussion about the position of the X-ray diffraction (XRD) reflections of these compounds is presented. It is known that by using XRD only, CZTSe can be identified but nothing can be said about the presence of some secondary phases. Thin films of CZTSe, Cu2SnSe3, ZnSe, SnSe, SnSe2, MoSe2 and a-Se were grown, which allowed their investigation by Raman spectroscopy (RS). Here we present all the Raman spectra of these phases and discuss the similarities with the spectra of CZTSe. The effective analysis depth for the common back-scattering geometry commonly used in RS measurements, as well as the laser penetration depth for photoluminescence (PL) were estimated for different wavelength values. The observed asymmetric PL band on a CZTSe film is compatible with the presence of CZTSe single-phase and is discussed in the scope of the fluctuating potentials’ model. The estimated bandgap energy is close to the values obtained from absorption measurements. In general, the phase identification of CZTSe benefits from the contributions of RS and PL along with the XRD discussion.info:eu-repo/semantics/publishedVersio

    Overview of the medium and high frequency telescopes of the LiteBIRD space mission

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    LiteBIRD is a JAXA-led Strategic Large-Class mission designed to search for the existence of the primordial gravitational waves produced during the inflationary phase of the Universe, through the measurements of their imprint onto the polarization of the cosmic microwave background (CMB). These measurements, requiring unprecedented sensitivity, will be performed over the full sky, at large angular scales, and over 15 frequency bands from 34 GHz to 448 GHz. The LiteBIRD instruments consist of three telescopes, namely the Low-, Medium-and High-Frequency Telescope (respectively LFT, MFT and HFT). We present in this paper an overview of the design of the Medium-Frequency Telescope (89{224 GHz) and the High-Frequency Telescope (166{448 GHz), the so-called MHFT, under European responsibility, which are two cryogenic refractive telescopes cooled down to 5 K. They include a continuous rotating half-wave plate as the first optical element, two high-density polyethylene (HDPE) lenses and more than three thousand transition-edge sensor (TES) detectors cooled to 100 mK. We provide an overview of the concept design and the remaining specific challenges that we have to face in order to achieve the scientific goals of LiteBIRD

    LiteBIRD satellite: JAXA's new strategic L-class mission for all-sky surveys of cosmic microwave background polarization

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    LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. LiteBIRD plans to map the cosmic microwave background (CMB) polarization over the full sky with unprecedented precision. Its main scientific objective is to carry out a definitive search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with an insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. To this end, LiteBIRD will perform full-sky surveys for three years at the Sun-Earth Lagrangian point L2 for 15 frequency bands between 34 and 448 GHz with three telescopes, to achieve a total sensitivity of 2.16 ΌK-arcmin with a typical angular resolution of 0.5° at 100 GHz. We provide an overview of the LiteBIRD project, including scientific objectives, mission requirements, top-level system requirements, operation concept, and expected scientific outcomes

    A molecular epidemiological study of respiratory viruses detected in Japanese children with acute wheezing illness

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    <p>Abstract</p> <p>Background</p> <p>Recent studies strongly suggest that some respiratory viruses are associated with the induction of acute wheezing and/or exacerbation of bronchial asthma. However, molecular epidemiology of these viruses is not exactly known.</p> <p>Methods</p> <p>Using PCR technology, we attempted to detect various respiratory viruses from 115 Japanese children. Furthermore, the detected viruses were subjected to homology, pairwise distance, and phylogenetic analysis.</p> <p>Results</p> <p>Viruses were detected from 99 (86.1%) patients. Respiratory syncytial virus (RSV) alone and human rhinovirus (HRV) alone were detected in 47 (40.9%) and 36 (31.3%) patients, respectively. Both RSV and HRV were detected in 14 (12.2%) patients. Human metapneumovirus (HMPV) alone and human parainfluenza virus (HPIV) alone were detected in 1 (0.9%) patient each, respectively. Homology and phylogenetic analyses showed that the RSV and HRV strains were classified into genetically diverse species or subgroups. In addition, RSV was the dominant virus detected in patients with no history of wheezing, whereas HRV was dominant in patients with a history of wheezing.</p> <p>Conclusions</p> <p>The results suggested that these genetically diverse respiratory viruses, especially RSV and HRV, might be associated with wheezing in Japanese children.</p

    Cost and utilization of blood transfusion associated with spinal surgeries in the United States

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    The purpose of this study was to examine factors associated with the utilization and cost of blood transfusion during and post-spinal fusion surgery. A retrospective, observational study of 42,029 inpatients undergoing spinal fusion surgery in United States hospitals participating in the PerspectiveTM Comparative Database for inpatient use was conducted. Descriptive analysis, logistic regression, and ordinary least squares (OLS) regression were used to describe the factors associated with the use and cost of allogeneic blood transfusion (ABT). Hospitalization costs were 18,690(SD=14,159)perpatient,erythropoietincostswere18,690 (SD=14,159) per patient, erythropoietin costs were 85.25 (SD=3,691.66) per patient, and topical sealant costs were 414.34(SD=1,020.06)perpatient.Sub−analysisofABTrestrictedtousersrevealedABTcostsrangedfrom414.34 (SD=1,020.06) per patient. Sub-analysis of ABT restricted to users revealed ABT costs ranged from 312.24 (SD=543.35) per patient with whole blood to $2,520 (SD=3,033.49) per patient with fresh frozen plasma. Patients that received hypotensive anesthesia (OR,1.61; 95% CI, 1.47–1.77), a volume expander (OR,1.95; 95% CI, 1.75–2.18), autologous blood (OR, 2.04; 95% CI, 1.71–2.42), or an erythropoietic agent (OR=1.64; 95% CI, 1.27–2.12) had a higher risk of ABT. Patients that received cell salvage had a lower risk of transfusion (OR=0.40; 95% CI, 0.32–0.50). Most blood avoidance techniques have low utilization or do not reduce the burden of transfusion associated with spinal fusion
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