2,438 research outputs found

    Atomic Layer Deposition of Ternary Indium/Tin/Aluminum Oxide Thin Films, their characterization and Transistor Performance under Illumination.

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    Multilayered heterostructures comprising of In 2 O 3, SnO 2, and Al 2 O 3 were studied for their application in thin-film transistors (TFT). The compositional influence of tin oxide on the properties of the thin-film, as well as on the TFT characteristics is investigated. The heterostructures are fabricated by atomic layer deposition (ALD) at 200°C, employing trimethylindium (TMI), tetrakis(dimethylamino)tin (TDMASn), trimethylaluminum (TMA), and water as precursors. After post-deposition annealing at 400°C the thin-films are found to be amorphous, however, they show a discrete layer structure of the individual oxides of uniform film thickness and high optical transparency in the visible region. Incorporation of only two monolayers of Al 2 O 3 in the active semiconducting layer the formation of oxygen vacancies can be effectively suppressed, resulting in an improved semiconducting and switching behavior. The heterostacks comprising of In 2 O 3 /SnO 2 /Al 2 O 3 are incorporated into TFT devices, exhibiting a saturation field-effect mobility (µ sat ) of 2.0 cm 2 ·V -1 s -1, a threshold-voltage (V th ) of 8.6 V, a high current on/off ratio (I On /I Off ) of 1.0·10 7, and a subthreshold swing (SS) of 485 mV·dec -1. The stability of the TFT under illumination is also altered to a significant extent. A change in the transfer characteristic towards conductive behavior is evident when illuminated with light of an energy of 3.1 eV (400 nm)

    Computational methods for metabolomic data analysis of ion mobility spectrometry data-reviewing the state of the art

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    Ion mobility spectrometry combined with multi-capillary columns (MCC/IMS) is a well known technology for detecting volatile organic compounds (VOCs). We may utilize MCC/IMS for scanning human exhaled air, bacterial colonies or cell lines, for example. Thereby we gain information about the human health status or infection threats. We may further study the metabolic response of living cells to external perturbations. The instrument is comparably cheap, robust and easy to use in every day practice. However, the potential of the MCC/IMS methodology depends on the successful application of computational approaches for analyzing the huge amount of emerging data sets. Here, we will review the state of the art and highlight existing challenges. First, we address methods for raw data handling, data storage and visualization. Afterwards we will introduce de-noising, peak picking and other pre-processing approaches. We will discuss statistical methods for analyzing correlations between peaks and diseases or medical treatment. Finally, we study up-to-date machine learning techniques for identifying robust biomarker molecules that allow classifying patients into healthy and diseased groups. We conclude that MCC/IMS coupled with sophisticated computational methods has the potential to successfully address a broad range of biomedical questions. While we can solve most of the data pre-processing steps satisfactorily, some computational challenges with statistical learning and model validation remain

    Lethal and Sublethal Effects of Methoxyfenozide on the Development, Survival and Reproduction on of the Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae)

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    The lethal and sublethal effects of the ecdysone agonist methoxyfenozide on the fall armyworm, Spodoptera frugiperda (J. E. Smith), were investigated by feeding a methoxyfenozide-treated diet to fifth instars until pupation in doses corresponding to the LC10 and LC25 for the compound. Larval mortality reached 8% and 26% in the low and high concentration groups, respectively, on the seventh day of the experiment. A progressive larval mortality of 12% for the LC10 and 60% for the LC25 was observed before pupation. Treated larvae exhibited lower pupal weights, higher pupal mortality, presence of deformed pupae, and more deformed adults than untreated larvae. The incorporation of methoxyfenozide into the diet had a significant effect on the timing of larval development. The development period for males and females was about seven days longer than the controls for both concentrations tested. In contrast, the compound affected neither pupae nor adult longevity. Finally, S. frugiperda adults that resulted from fifth instars treated with methoxyfenozide were not affected in their mean cumulative number of eggs laid per female (fecundity), nor percentages of eggs hatched (fertility), or the sex ratio. Our results suggest that the combination of lethal and sublethal effects of methoxyfenozide may have important implications for the population dynamics of the fall armyworm

    HVEM, a cosignaling molecular switch, and its interactions with BTLA, CD160 and LIGHT

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    [EN] Temporal and spatial expression of cosignaling receptors and their ligands regulates the early stages of T-cell activation (signal 1, T-cell receptor (TCR) signaling and signal 2, costimulation/ coinhibition), clonal expansion and T-cell survival during their differentiation towards effector T cells. Once the inflammatory stimulus is eliminated, effector T cells return to homeostasis after undergoing a contraction phase by activation-induced cell death and the intervention of ligands for coinhibitory receptors, leaving a population of long-term memory T cells. The expression of ligands for coinhibitory receptors on hematopoietic cells and, more importantly, on non-hematopoietic cells of peripheral tissues is a key process in tuning the functional activity of effector T cells to prevent excess tissue inflammation that may lead to immunopathology and subsequent tissue dysfunctionS

    Spin Seebeck insulator

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    Thermoelectric generation is an essential function of future energy-saving technologies. However, this generation has been an exclusive feature of electric conductors, a situation which inflicts a heavy toll on its application; a conduction electron often becomes a nuisance in thermal design of devices. Here we report electric-voltage generation from heat flowing in an insulator. We reveal that, despite the absence of conduction electrons, a magnetic insulator LaY2Fe5O12 converts a heat flow into spin voltage. Attached Pt films transform this spin voltage into electric voltage by the inverse spin Hall effect. The experimental results require us to introduce thermally activated interface spin exchange between LaY2Fe5O12 and Pt. Our findings extend the range of potential materials for thermoelectric applications and provide a crucial piece of information for understanding the physics of the spin Seebeck effect.Comment: 19 pages, 5 figures (including supplementary information

    Chiari’s Network as a Cause of Fetal and Neonatal Pathology

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    Chiari’s network is a remnant of the eustachian valve located in the right atrium. Incomplete involution of the fetal sinus venosus valves results in “redundant” Chiari’s network, which may compromise cardiovascular function. This report describes a case with the novel finding of prenatal compromise due to redundant Chiari’s network and an uncommon case with significant postnatal symptoms. In both cases, the symptoms (fetal hydrops and postnatal cyanosis) resolved spontaneously. The variety of cardiovascular pathologies described in the literature is believed to be associated with persistence of a Chiari network. Knowledge about this not always harmless structure is important for perinatologists, pediatricians, and pediatric cardiologists alike. The clinical importance of this rare pathology is that prenatal counseling may anticipate a generally positive outcome and that surgical intervention generally should be avoided

    Endocardial Fibroelastosis in a 57-Year-Old Transplant Recipient

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    Endocardial fibroelastosis (EFE) is characterized by deposition of collagen and elastin leading to ventricular hypertrophy and diffuse endocardial thickening. Here we report (for the first time in Korea) the case of a EFE presenting with heart failure. The patient was a 57-year-old woman who had complained of dyspnea on exertion {New York Heart Association (NYHA) functional class 3} and abdominal distension at the time of hospital admission. Echocardiography showed severe diastolic dysfunction with normal systolic function. On MRI, the contrast-enhanced delayed myocardial image demonstrated hyperenhancement in the endocardium. Owing to progressive heart failure, the patient was transplanted. Histological examination of the explanted heart showed irregularly thickened endocardium with fibrosis and elastosis in the both ventricles, compatible with the diagnosis of EFE

    Migraine aura: retracting particle-like waves in weakly susceptible cortex

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    Cortical spreading depression (SD) has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD and aura symptoms on the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value [sigma]=1 at the instability point. We predict that human cortex is only weakly susceptible to SD ([sigma]<1), and support this prediction by directly matching visual aura symptoms with anatomical landmarks using fMRI retinotopic mapping. We discuss the increased dynamical repertoire of cortical tissue close to [sigma]=1, in particular, the resulting implications on migraine pharmacology that is hitherto tested in the regime ([sigma]>>1), and potentially silent aura occurring below a second bifurcation point at [sigma]=0 on the susceptible scale

    Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years.

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    Asian summer monsoon (ASM) variability and its long-term ecological and societal impacts extending back to Neolithic times are poorly understood due to a lack of high-resolution climate proxy data. Here, we present a precisely dated and well-calibrated tree-ring stable isotope chronology from the Tibetan Plateau with 1- to 5-y resolution that reflects high- to low-frequency ASM variability from 4680 BCE to 2011 CE. Superimposed on a persistent drying trend since the mid-Holocene, a rapid decrease in moisture availability between ∼2000 and ∼1500 BCE caused a dry hydroclimatic regime from ∼1675 to ∼1185 BCE, with mean precipitation estimated at 42 ± 4% and 5 ± 2% lower than during the mid-Holocene and the instrumental period, respectively. This second-millennium-BCE megadrought marks the mid-to late Holocene transition, during which regional forests declined and enhanced aeolian activity affected northern Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE contributed to the shift of Neolithic cultures in northern China and likely triggered human migration and societal transformation
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