271 research outputs found

    Bulk superconductivity in Pb-substituted BiS2_{\bf 2}-based compounds studied by hard-x-ray spectroscopy

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    In this study, we investigate the bulk electronic structure of Pb-substituted LaO0.5_{0.5}F0.5_{0.5}BiS2_2 single crystals, using two types of hard-x-ray spectroscopy. High-energy-resolution fluorescence-detected x-ray absorption spectroscopy revealed a spectral change at low temperatures. Using density functional theory (DFT) simulations, we find that the temperature-induced change originates from a structural phase transition, similar to the pressure-induced transition in LaO0.5_{0.5}F0.5_{0.5}BiS2_2. This finding suggests that the mechanism of bulk superconductivity induced by Pb substitution is the same as that under high pressure. Furthermore, a novel low-valence state with a mixture of divalent and trivalent Bi ions is discovered using hard x-ray photoemission spectroscopy with the aid of DFT calculations.Comment: 8 pages, 6 figures, 1 tabl

    Основи маркетингу (для студентів)

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    Серія навчально-методичних посібників містить розширені матеріали, що необхідні для розуміння та ведення підприємницької діяльності, розуміння механізмів пошуку та ідентифікації можливостей для бізнесу, визначенні питань управління підприємницькою діяльністю, правових основ підприємництва, соціальної відповідальності бізнесу та його маркетингової діяльності. Призначено для студентів ВНЗ І-II рівня акредитації економічних, управлінських та інженерних спеціальностей, підприємців початківців та фахівців практиків

    Perinatal Asphyxia Affects Rat Auditory Processing: Implications for Auditory Perceptual Impairments in Neurodevelopmental Disorders

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    Perinatal asphyxia, a naturally and commonly occurring risk factor in birthing, represents one of the major causes of neonatal encephalopathy with long term consequences for infants. Here, degraded spectral and temporal responses to sounds were recorded from neurons in the primary auditory cortex (A1) of adult rats exposed to asphyxia at birth. Response onset latencies and durations were increased. Response amplitudes were reduced. Tuning curves were broader. Degraded successive-stimulus masking inhibitory mechanisms were associated with a reduced capability of neurons to follow higher-rate repetitive stimuli. The architecture of peripheral inner ear sensory epithelium was preserved, suggesting that recorded abnormalities can be of central origin. Some implications of these findings for the genesis of language perception deficits or for impaired language expression recorded in developmental disorders, such as autism spectrum disorders, contributed to by perinatal asphyxia, are discussed

    Symptomatic asymmetry in the first six months of life: differential diagnosis

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    Asymmetry in infancy is a clinical condition with a wide variation in appearances (shape, posture, and movement), etiology, localization, and severity. The prevalence of an asymmetric positional preference is 12% of all newborns during the first six months of life. The asymmetry is either idiopathic or symptomatic. Pediatricians and physiotherapists have to distinguish symptomatic asymmetry (SA) from idiopathic asymmetry (IA) when examining young infants with a positional preference to determine the prognosis and the intervention strategy. The majority of cases will be idiopathic, but the initial presentation of a positional preference might be a symptom of a more serious underlying disorder. The purpose of this review is to synthesize the current information on the incidence of SA, as well as the possible causes and the accompanying signs that differentiate SA from IA. This review presents an overview of the nine most prevalent disorders in infants in their first six months of life leading to SA. We have discovered that the literature does not provide a comprehensive analysis of the incidence, characteristics, signs, and symptoms of SA. Knowledge of the presented clues is important in the clinical decision making with regard to young infants with asymmetry. We recommend to design a valid and useful screening instrument

    Q344ter Mutation Causes Mislocalization of Rhodopsin Molecules That Are Catalytically Active: A Mouse Model of Q344ter-Induced Retinal Degeneration

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    Q344ter is a naturally occurring rhodopsin mutation in humans that causes autosomal dominant retinal degeneration through mechanisms that are not fully understood, but are thought to involve an early termination that removed the trafficking signal, QVAPA, leading to its mislocalization in the rod photoreceptor cell. To better understand the disease mechanism(s), transgenic mice that express Q344ter were generated and crossed with rhodopsin knockout mice. Dark-reared Q344terrho+/− mice exhibited retinal degeneration, demonstrating that rhodopsin mislocalization caused photoreceptor cell death. This degeneration is exacerbated by light-exposure and is correlated with the activation of transducin as well as other G-protein signaling pathways. We observed numerous sub-micrometer sized vesicles in the inter-photoreceptor space of Q344terrho+/− and Q344terrho−/− retinas, similar to that seen in another rhodopsin mutant, P347S. Whereas light microscopy failed to reveal outer segment structures in Q344terrho−/− rods, shortened and disorganized rod outer segment structures were visible using electron microscopy. Thus, some Q344ter molecules trafficked to the outer segment and formed disc structures, albeit inefficiently, in the absence of full length wildtype rhodopsin. These findings helped to establish the in vivo role of the QVAPA domain as well as the pathways leading to Q344ter-induced retinal degeneration

    Outline of the New Construction Project over the Kelani River

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    Abstract: This project is to construct part of urban expressway in the most congested area in Colombo, Sri Lanka. It is featured by a long-span prestressed concrete extradosed bridge and elevated steel box girders supported by steel portal frame piers. This paper presents outline of the project by focusing on the advancement of technologies employed in this design, construction method and long-term durability
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