2,216 research outputs found

    Surface Sr segregation behaviors in a model thin film perovskite cathode for solid oxide fuel cells

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    Surface cation segregation, strontium (Sr) in particular, has been considered as one of crucial barriers to achieving a fast surface oxygen exchange rate of perovskite oxide electrodes for solid oxide fuel cells (SOFCs). However, the major driving force for the segregation phenomenon still remains unknown, and thus it is also unknown how to maximize the cathode performance. In this work, we fabricated epitaxial thin films of SrTi1-xFexO3-δ (STF) via pulsed laser deposition (PLD) and quantitatively characterized their microstructures, surface chemical compositions and oxygen exchange rates by a range of analysis tools, in this case HR-TEM, HR-XRD, angle resolved X-ray photoelectron spectroscopy (AR-XPS) and electrical conductivity relaxation (ECR). The use of well-defined epitaxial thin films not only guarantees high precision, reproducibility and reliability of the surface properties, but also enables us to control the degree of misfit strain by varying the choice of the substrate and the target composition. This, in combination with density functional theory (DTF) simulation, enabled to reveal a close relationship between the degree of surface Sr segregation and the misfit strain and thereby to identify the governing factors for the Sr segregation phenomenon

    Immunoglobulin G Subclass Deficiency is the Major Phenotype of Primary Immunodeficiency in a Korean Adult Cohort

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    Primary immunodeficiency disease (PID) is a rare disorder in adults. Most often, serious forms are detected during infancy or childhood. However, mild forms of PID may not be diagnosed until later in life, and some types of humoral immunodeficiency may occur in adulthood. The purpose of this study was to identify clinical features of PID in Korean adults. A retrospective study was performed on 55 adult patients who were diagnosed as PID between January 1998 and January 2009 at a single tertiary medical center in Korea. IgG subclass deficiency was the most common phenotype (67%, 37/55), followed by total IgG deficiency (20%, 11/55), IgM deficiency (7%, 4/55), common variable immunodeficiency (2%, 1/55), and X-linked agammaglobulinemia (2%, 1/55). IgG3 and IgG4 were the most affected subclasses. Upper and lower respiratory tract infections (76%) were the most frequently observed symptoms, followed by multiple site infection (11%), urinary tract infection, and colitis. Bronchial asthma, rhinitis, and several autoimmune diseases were common associated diseases. IgG and IgG subclass deficiency should be considered in adult patients presenting with recurrent upper and lower respiratory infections, particularly in those with respiratory allergies or autoimmune diseases

    Strengthening deep-learning models for intracranial hemorrhage detection: strongly annotated computed tomography images and model ensembles

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    Background and purposeMultiple attempts at intracranial hemorrhage (ICH) detection using deep-learning techniques have been plagued by clinical failures. We aimed to compare the performance of a deep-learning algorithm for ICH detection trained on strongly and weakly annotated datasets, and to assess whether a weighted ensemble model that integrates separate models trained using datasets with different ICH improves performance.MethodsWe used brain CT scans from the Radiological Society of North America (27,861 CT scans, 3,528 ICHs) and AI-Hub (53,045 CT scans, 7,013 ICHs) for training. DenseNet121, InceptionResNetV2, MobileNetV2, and VGG19 were trained on strongly and weakly annotated datasets and compared using independent external test datasets. We then developed a weighted ensemble model combining separate models trained on all ICH, subdural hemorrhage (SDH), subarachnoid hemorrhage (SAH), and small-lesion ICH cases. The final weighted ensemble model was compared to four well-known deep-learning models. After external testing, six neurologists reviewed 91 ICH cases difficult for AI and humans.ResultsInceptionResNetV2, MobileNetV2, and VGG19 models outperformed when trained on strongly annotated datasets. A weighted ensemble model combining models trained on SDH, SAH, and small-lesion ICH had a higher AUC, compared with a model trained on all ICH cases only. This model outperformed four deep-learning models (AUC [95% C.I.]: Ensemble model, 0.953[0.938–0.965]; InceptionResNetV2, 0.852[0.828–0.873]; DenseNet121, 0.875[0.852–0.895]; VGG19, 0.796[0.770–0.821]; MobileNetV2, 0.650[0.620–0.680]; p < 0.0001). In addition, the case review showed that a better understanding and management of difficult cases may facilitate clinical use of ICH detection algorithms.ConclusionWe propose a weighted ensemble model for ICH detection, trained on large-scale, strongly annotated CT scans, as no model can capture all aspects of complex tasks

    The spatial distribution and origin of the FUV excess in early-type galaxies

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    We present surface photometry of a sample of 52 galaxies from the GALEX and 2MASS data archives, these include 32 normal elliptical galaxies, 10 ellipticals with weak Liner or other nuclear activity, and 10 star forming ellipticals or early-type spirals. We examine the spatial distribution of the Far Ultra-Violet excess in these galaxies, and its correlation with dynamical and stellar population properties of the galaxies. From aperture photometry we find that all galaxies except for recent major remnants and galaxies with ongoing star formation show a positive gradient in the (FUV-NUV) colour determined from the GALEX images. The logarithmic gradient does not correlate with any stellar population parameter, but it does correlate with the central velocity dispersion. The strength of the excess on the other hand, correlates with both [alpha/Fe] and [Z/H], but more strongly with the former. We derive models of the underlying stellar population from the 2MASS H-band images, and the residual of the image from this model reveals a map of the centrally concentrated FUV excess. We examine a possible hypothesis for generating the FUV excess and the radial gradient in its strength, involving a helium abundance gradient set up early in the formation process of the galaxies. If this hypothesis is correct, the persistence of the gradients to the present day places a strong limit on the importance of dry mergers in the formation of ellipticals.Comment: 36 pages, accepted for publication in MNRAS. Appendices will appear in online journal only. This version has reduced resolution for the figure in Appendix B to comply with arXiv size limit

    Randomized Comparison of Four-Times-Daily versus Once-Daily Intravenous Busulfan in Conditioning Therapy for Hematopoietic Cell Transplantation

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    AbstractSixty patients were randomized to receive intravenous busulfan (iBU) either as 0.8 mg/kg, over 2 hours 4 times a day (BU4 arm) or 3.2 mg/kg, over 3 hours once a day (BU1 arm) in conditioning therapy for hematopoietic cell transplantation. The complete pharmacokinetic parameters for the first busulfan dose were obtained from all patients and were comparable between the 2 arms: for the BU4 and BU1 groups, elimination half-life (mean ± SD) was 2.75 ± 0.22 versus 2.83 ± 0.21 hours, estimated daily AUC was 6058.0 ± 1091.9 versus 6475.5 ± 1099.4 μM·min per day, and clearance was 2.05 ± 0.36 versus 1.91 ± 0.31 mL/min/kg, respectively. Times to engraftment after transplantation were similar between the 2 arms. No significant differences were evident in the occurrence of acute graft-versus-host disease (aGVHD) and hepatic veno-occlusion disease (VOD). Moreover, other toxicities observed within 100 days after transplantation were not significantly different between the 2 arms. The cumulative incidence of nonrelapse mortality was 20.8% in BU4 arm and 13.3% in BU1 arm. In conclusion, our randomized study demonstrates that the pharmacokinetic profiles and posttransplant complications are similar for once-daily iBU and traditional 4-times-daily iBU

    Tricuspid regurgitation: a hidden risk factor for atrial fibrillation related stroke?

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    Background and purposeTricuspid regurgitation (TR) is a common but overlooked valvular disease, and its association with the etiologic subtypes of ischemic stroke is unclear. We explored the relationship between TR and atrial fibrillation (AF) in patients with acute ischemic stroke.MethodsThis retrospective analysis of ongoing stroke registry assessed 6,886 consecutive acute ischemic stroke patients who underwent transthoracic echocardiography during their in-hospital care. Multivariable logistic regression models adjusted for age, sex, stroke characteristics, and echocardiographic indices were used to investigate the association between TR and total AF, and newly diagnosed AF during hospitalization and a 1-year follow-up period, respectively.ResultsTR was present in 877 (12.7%) patients (mild, 9.9%; moderate, 2.4%; severe, 0.5%). AF was identified in 24.1% (medical history, 11.1%; first detected in the emergency room, 6.6%; newly diagnosed after admission, 6.4%). TR was associated with AF [adjusted odds ratio (aOR) 4.87 (95% confidence interval (CI), 2.63–9.03)], compared with no/trivial TR. The association between TR and AF was consistent regardless of severity (aOR [95% CI], 4.57 [2.63–7.94] for mild and 7.05 [2.57–19.31] for moderate-to-severe TR) or subtype of TR (5.44 [2.91–10.14] for isolated and 3.81 [2.00–7.28] for non-isolated TR). Among the AF-naïve patients at admission, TR was associated with newly diagnosed AF during hospitalization and a 1-year follow-up period (aOR [95% CI], 2.68 [1.81–3.97]).ConclusionsTR is associated with AF in acute ischemic stroke patients regardless of severity and subtypes of TR. TR is also associated with newly diagnosed AF after stroke

    Progression of Prostate Cancer Despite an Extremely Low Serum Level of Prostate-Specific Antigen

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    A 61-year-old man who had been diagnosed with prostate cancer 9 years ago and had been treated with pelvic irradiation and intermittent androgen deprivation therapy visited the emergency room because of back pain and weakness in both legs. Spine magnetic resonance imaging showed a lumbar epidural mass and spine metastasis. The whole-body workup revealed multiple metastases to the lymph nodes, bone, liver, and lung. The serum prostate-specific antigen was 0.02 ng/ml. He underwent laminectomy, posterior fixation, and epidural mass excision, and metastatic adenocarcinoma from the prostate was diagnosed. The patient underwent 1 cycle of docetaxel-based chemotherapy. More chemotherapy could not be done because of his general weakness. The patient died one month later of multiple organ failure

    The genome sequence of Xanthomonas oryzae pathovar oryzae KACC10331, the bacterial blight pathogen of rice

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    The nucleotide sequence was determined for the genome of Xanthomonas oryzae pathovar oryzae (Xoo) KACC10331, a bacterium that causes bacterial blight in rice (Oryza sativa L.). The genome is comprised of a single, 4 941 439 bp, circular chromosome that is G + C rich (63.7%). The genome includes 4637 open reading frames (ORFs) of which 3340 (72.0%) could be assigned putative function. Orthologs for 80% of the predicted Xoo genes were found in the previously reported X.axonopodis pv. citri (Xac) and X.campestris pv. campestris (Xcc) genomes, but 245 genes apparently specific to Xoo were identified. Xoo genes likely to be associated with pathogenesis include eight with similarity to Xanthomonas avirulence (avr) genes, a set of hypersensitive reaction and pathogenicity (hrp) genes, genes for exopolysaccharide production, and genes encoding extracellular plant cell wall-degrading enzymes. The presence of these genes provides insights into the interactions of this pathogen with its gramineous host
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