114 research outputs found

    Oxygen-deficient triple perovskites as highly active and durable bifunctional electrocatalysts for oxygen electrode reactions

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    Highly active and durable bifunctional oxygen electrocatalysts have been of pivotal importance for renewable energy conversion and storage devices, such as unitized regenerative fuel cells and metal-air batteries. Perovskite-based oxygen electrocatalysts have emerged as promising nonprecious metal bifunctional electrocatalysts, yet their catalytic activity and stability still remain to be improved. We report a high-performance oxygen electrocatalyst based on a triple perovskite, Nd1.5Ba1.5CoFeMnO9-delta (NBCFM), which shows superior activity and durability for oxygen electrode reactions to single and double perovskites. When hybridized with nitrogen-doped reduced graphene oxide (N-rGO), the resulting NBCFM/N-rGO catalyst shows further boosted bifunctional oxygen electrode activity (0.698 V), which surpasses that of Pt/C (0.801 V) and Ir/C (0.769 V) catalysts and which, among the perovskite-based electrocatalysts, is the best activity reported to date. The superior catalytic performances of NBCFM could be correlated to its oxygen defect rich structure, lower charge transfer resistance, and smaller hybridization strength between O 2p and Co 3d orbitals

    Pathogenicity of severe fever with thrombocytopenia syndrome virus in mice regulated in type I interferon signaling

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    Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic disease, which causes high fever, thrombocytopenia, and death in humans and animals in East Asian countries. The pathogenicity of SFTS virus (SFTSV) remains unclear. We intraperitoneally infected three groups of mice: wild-type (WT), mice treated with blocking anti-type I interferon (IFN)-α receptor antibody (IFNAR Ab), and IFNAR knockout (IFNAR−/−) mice, with four doses of SFTSV (KH1, 5 × 105 to 5 × 102 FAID50). The WT mice survived all SFTSV infective doses. The IFNAR Ab mice died within 7 days post-infection (dpi) with all doses of SFTSV except that the mice were infected with 5 × 102 FAID50 SFTSV. The IFNAR−/− mice died after infection with all doses of SFTSV within four dpi. No SFTSV infection caused hyperthermia in any mice, whereas all the dead mice showed hypothermia and weight loss. In the WT mice, SFTSV RNA was detected in the eyes, oral swabs, urine, and feces at 5 dpi. Similar patterns were observed in the IFNAR Ab and IFNAR−/− mice after 3 dpi, but not in feces. The IFNAR Ab mice showed viral shedding until 7 dpi. The SFTSV RNA loads were higher in organs of the IFNAR−/− mice compared to the other groups. Histopathologically, coagulation necrosis and mononuclear inflammatory cell infiltration in the liver and white pulp atrophy in the spleen were seen as the main lesions in the IFN signaling lacking mice. Immunohistochemically, SFTSV antigens were mainly detected in the marginal zone of the white pulp of the spleen in all groups of mice, but more viral antigens were observed in the spleen of the IFNAR−/− mice. Collectively, the IFN signaling-deficient mice were highly susceptible to SFTSV and more viral burden could be demonstrated in various excreta and organs of the mice when IFN signaling was inhibited.The research was supported by the Republic of Korea (Government-wide R&D Fund project for infectious disease research (GFID), HG18C0084)

    Development of New Ensemble Methods Based on the Performance Skills of Regional Climate Models over South Korea

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    In this paper, the prediction skills of five ensemble methods for temperature and precipitation are discussed by considering 20 yr of simulation results (from 1989 to 2008) for four regional climate models (RCMs) driven by NCEP-Department of Energy and ECMWF Interim Re-Analysis (ERA-Interim) boundary conditions. The simulation domain is the Coordinated Regional Downscaling Experiment (CORDEX) for East Asia. and the number of grid points is 197 x 233 with a 50-km horizontal resolution. Three new performance-based ensemble averaging (PEA) methods are developed in this study using 1) bias, root-mean-square errors (RMSEs) and absolute correlation (PEA_BRC). RMSE and absolute correlation (PEA RAC), and RMSE and original correlation (PEA_ROC). The other two ensemble methods are equal-weighted averaging (EWA) and multivariate linear regression (Mul_Reg). To derive the weighting coefficients and cross validate the prediction skills of the five ensemble methods. the authors considered 15-yr and 5-yr data, respectively, from the 20-yr simulation data. Among the five ensemble methods, the Mul_Reg (EWA) method shows the best (worst) skill during the training period. The PEA_RAC and PEA_ROC methods show skills that are similar to those of Mul_Reg during the training period. However, the skills and stabilities of Mul_Reg were drastically reduced when this method was applied to the prediction period. But, the skills and stabilities of PEA_RAC were only slightly reduced in this case. As a result. PEA RAC shows the best skill, irrespective of the seasons and variables, during the prediction period. This result confirms that the new ensemble method developed in this study. PEA_RAC. can be used for the prediction of regional climate.open7

    Whole-genome, transcriptome, and methylome analyses provide insights into the evolution of platycoside biosynthesis in Platycodon grandiflorus, a medicinal plant

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    Triterpenoid saponins (TSs) are common plant defense phytochemicals with potential pharmaceutical properties. Platycodon grandiflorus (Campanulaceae) has been traditionally used to treat bronchitis and asthma in East Asia. The oleanane-type TSs, platycosides, are a major component of the P. grandiflorus root extract. Recent studies show that platycosides exhibit anti-inflammatory, antiobesity, anticancer, antiviral, and antiallergy properties. However, the evolutionary history of platycoside biosynthesis genes remains unknown. In this study, we sequenced the genome of P. grandiflorus and investigated the genes involved in platycoside biosynthesis. The draft genome of P. grandiflorus is 680.1Mb long and contains 40,017 protein-coding genes. Genomic analysis revealed that the CYP716 family genes play a major role in platycoside oxidation. The CYP716 gene family of P. grandiflorus was much larger than that of other Asterid species. Orthologous gene annotation also revealed the expansion of beta -amyrin synthases (bASs) in P. grandiflorus, which was confirmed by tissue-specific gene expression. In these expanded gene families, we identified key genes showing preferential expression in roots and association with platycoside biosynthesis. In addition, whole-genome bisulfite sequencing showed that CYP716 and bAS genes are hypomethylated in P. grandiflorus, suggesting that epigenetic modification of these two gene families affects platycoside biosynthesis. Thus whole-genome, transcriptome, and methylome data of P. grandiflorus provide novel insights into the regulation of platycoside biosynthesis by CYP716 and bAS gene families

    Comparison of the Usefulness of CBCT and MRI in TMD Patients According to Clinical Symptoms and Age

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    Recently, the number of patients who visit the hospital with symptoms of temporomandibular joint disorders (TMD) has been gradually increasing, and the need for special imaging such as cone-beam computed tomography (CBCT) and magnetic resonance imaging (MRI) is increasing for accurate diagnosis and treatment. The purpose of this study was to help the image guideline by comparing the usefulness of CBCT and MRI according to the clinical symptoms of TMD patients and further examining whether the usefulness varies with age. A total of 473 temporomandibular joints (TMJs) with clinical symptoms of TMD who underwent both CBCT and MRI examinations were retrospectively reviewed. Clinical symptoms included pain, sound and limited mouth opening. The CBCT findings included sclerosis, flattening, erosion and osteophyte, while the MRI findings were defined as disc deformity, disc derangement or joint effusion. Joints were divided according to the presence of CBCT and MRI findings as follows: type I (neither CBCT nor MRI findings), type II (only CBCT findings), type III (only MRI findings) and type IV (both CBCT and MRI findings). We assessed the usefulness of the two imaging modalities by comparing the frequency of those four groups according to clinical symptoms and age. In TMD patients with the clinical symptoms, MRI and CBCT are complementary, but if it is difficult to choose the first of these two modalities, MRI is more recommended, and the younger the patient, the more the MRI is recommended

    Assessment of bone marrow fat fractions in the mandibular condyle head using the iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method.

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    The prevalence of temporomandibular joint disorder (TMD) is gradually increasing, and magnetic resonance imaging (MRI) is becoming increasingly common as a modality used to diagnose TMD. Edema and osteonecrosis in the bone marrow of the mandibular condyle have been considered to be precursors of osteoarthritis, but these changes are not evaluated accurately and quantitatively on routine MRI. The iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL-IQ) method, as a cutting-edge MRI technique, can separate fat and water using three asymmetric echo times and the three-point Dixon method. The purpose of this study was to analyze the quantitative fat fraction (FF) in the mandibular condyle head using the IDEAL-IQ method. Seventy-nine people who underwent MRI using IDEAL-IQ were investigated and divided into 1) the control group, without TMD symptoms, and 2) the TMD group, with unilateral temporomandibular joint (TMJ) pain. In both groups, the FF of the condyle head in the TMJ was analyzed by two oral and maxillofacial radiologists. In the TMD group, 29 people underwent cone-beam computed tomography (CBCT) and the presence or absence of bony changes in the condylar head was evaluated. The FF measurements of the condyle head using IDEAL-IQ showed excellent inter-observer and intra-observer agreement. The average FF of the TMD group was significantly lower than that of the control group (p < 0.05). In the TMD group, the average FF values of joints with pain and joints with bony changes were significantly lower than those of joints without pain or bony changes, respectively (p < 0.05). The FF using IDEAL-IQ in the TMJ can be helpful for the quantitative diagnosis of TMD

    Rebound phenomenon and its risk factors after hemiepiphysiodesis using tension band plate in children with coronal angular deformity

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    Background This study was performed to evaluate the rebound phenomenon after the correction of coronal angular deformity by hemiepiphysiodesis using tension band plate in children and to identify its risk factors. Methods We reviewed 50 children (mean age, 11.0 +/- 2.5 years) with 94 physes who had undergone hemiepiphysiodesis using tension band plate due to coronal angular deformity of the lower limb. Patients&apos; demographic data including sex, age at initial surgery and plate removal, affected bone (distal femur or proximal tibia), affected side, and body mass index were collected. The mechanical lateral distal femoral angle (mLDFA) and the mechanical medial proximal tibial angle (mMPTA) were measured from the teleradiogram, Physes were divided into rebound and non-rebound group, and rebound group was defined as the physes which had &gt;= 5 degrees of mLDFA or mMPTA returning to its original deformity. Generalized estimating equation based multivariable analysis was used to identify the risk factors for the rebound phenomenon after the deformity correction. Results A total of 41 physes classified into rebound group and 53 physes into non-rebound group. There were significant differences in the age at initial surgery (p = 0.004), the age at implant removal (p = 0.002), the amount of correction (p = 0.001), and the rate of correction (p &lt; 0.001) between two groups. The rate of correction was significantly associated with the rebound phenomenon (p = 0.044). The risk of rebound phenomenon was 1.2-fold higher as the rate of correction increased by 1 degrees per year. The cutoff values of the correction rate between the two groups were 6.9 degrees/year (p &lt; 0.001). Conclusions This study showed that the rebound group had younger age and faster correction rate than those in the non-rebound group. In addition, the correction rate for deformity was a significant risk factor for the rebound phenomenon after hemiepiphysiodesis using the tension band plate. Close monitoring after implant removal is required for children who have a rapid correction rate over 7 degrees/year.N

    Arctic Oscillation responses to greenhouse warming and role of synoptic eddy feedback

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    This study investigates possible changes in the leading mode over the Northern Hemisphere, representing the Arctic Oscillation (AO), in response to the projected increases in greenhouse gas concentrations. This is performed by comparing present-day and future patterns simulated by a relatively high-resolution atmospheric general circulation model. It is demonstrated that the dipole pattern associated with the AO distinctively shifts poleward in the future climate. The poleward shift is more pronounced over the Pacific region than over the Atlantic region. This change in the AO pattern is consistent with the change in the synoptic eddy feedback, estimated from the divergence of the eddy-vorticity flux, indicating a close linkage between the AO change and the change in the synoptic eddy feedback. Further analysis of changes in eddy feedback strength suggests a possible hypothesis that the poleward shift of the jet stream and storm tracks can make synoptic eddy feedback more effective over the higher latitudes, which in turn enhances the poleward shift of the AO mode.X1113sciescopu
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