206 research outputs found

    A Proposal for a Standardized Fault Description Format to Study Active Intraplate Tectonics in the Korean Peninsula

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    Intraplate faulting and the resultant earthquakes are not well understood because of their complex distribution, long period of seismic recurrence, and poor exposure of surface rupture. Pre-existing weaknesses should be studied to understand intraplate faulting and earthquakes. We are developing a long-term project to understand Korean-type intraplate fault behavior and recurrence intervals. As the first step, we will establish an integrated system for production, analysis, and management of fault data related to active crustal deformation. Here we propose a new format for fault data description and management

    Perovskite-polymer composite cross-linker approach for highly-stable and efficient perovskite solar cells.

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    Manipulation of grain boundaries in polycrystalline perovskite is an essential consideration for both the optoelectronic properties and environmental stability of solar cells as the solution-processing of perovskite films inevitably introduces many defects at grain boundaries. Though small molecule-based additives have proven to be effective defect passivating agents, their high volatility and diffusivity cannot render perovskite films robust enough against harsh environments. Here we suggest design rules for effective molecules by considering their molecular structure. From these, we introduce a strategy to form macromolecular intermediate phases using long chain polymers, which leads to the formation of a polymer-perovskite composite cross-linker. The cross-linker functions to bridge the perovskite grains, minimizing grain-to-grain electrical decoupling and yielding excellent environmental stability against moisture, light, and heat, which has not been attainable with small molecule defect passivating agents. Consequently, all photovoltaic parameters are significantly enhanced in the solar cells and the devices also show excellent stability

    Fabrication of pyramidal probes with various periodic patterns and a single nanopore

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    The nanometer-scale patterned pyramidal probe with an electron beam-induced nanopore on the pyramid apex is an excellent candidate for an optical biosensor. The nanoapertures surrounded with various periodic groove patterns on the pyramid sides were fabricated using a focused ion beam technique, where the optical characteristics of the fabricated apertures with rectangular, circular, and elliptical groove patterns were investigated. The elliptical groove patterns on the pyramid were designed to maintain an identical distance between the grooves and the apex for the surface waves and, among the three patterns, the authors observed the highest optical transmission from the elliptically patterned pyramidal probe. A 103-fold increase of the transmitted optical intensity was observed after patterning with elliptical grooves, even without an aperture on the pyramid apex. The nanopore on the apex of the pyramid was fabricated using electron beam irradiation and was optically characterized

    Highly active and stable stepped Cu surface for enhanced electrochemical CO₂ reduction to C₂H₄

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    Electrochemical CO₂ reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO₂ emissions from human activity. Copper represents an effective catalyst in reducing CO₂ to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Here we report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for C₂H₄ that can be maintained for over 200 hours. Computational studies reveal that these steps are thermodynamically favoured compared with Cu(100) surface under the operating conditions and the stepped surface favours C₂ products by suppressing the C₁ pathway and hydrogen production

    Highly active and stable stepped Cu surface for enhanced electrochemical CO₂ reduction to C₂H₄

    Get PDF
    Electrochemical CO₂ reduction to value-added chemical feedstocks is of considerable interest for renewable energy storage and renewable source generation while mitigating CO₂ emissions from human activity. Copper represents an effective catalyst in reducing CO₂ to hydrocarbons or oxygenates, but it is often plagued by a low product selectivity and limited long-term stability. Here we report that copper nanowires with rich surface steps exhibit a remarkably high Faradaic efficiency for C₂H₄ that can be maintained for over 200 hours. Computational studies reveal that these steps are thermodynamically favoured compared with Cu(100) surface under the operating conditions and the stepped surface favours C₂ products by suppressing the C₁ pathway and hydrogen production

    Correction: triple-negative, basal-like, and quintuple-negative breast cancers: better prediction model for survival

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    After the publication of this work [1], we found that there were some mistakes in calculating the percentage of composition in Table 1(1). Clinicopathologic characteristics of breast cancer subtypes. We are therefore providing the revised Table 1, with the updated data for rows Mucinous carcinoma, Metaplastic carcinoma and Others. In the sub-content of Table 1, Histological type, the total number of Others was corrected from 18 to 16, and the composition of Others type was slightly changed according to breast cancer subtypes. For IHC-Her2 subtype, the number of Others was changed from 4 to 3, and 6 cases which were previously unidentified were assigned to corresponding subtypes. One case to IHC-BLBC, 2 cases to IHC-QNBC/5NP and 3 cases to IHC-TNCB. There was no effect on statistical analysis with the correction.

    Correction: triple-negative, basal-like, and quintuple-negative breast cancers: better prediction model for survival

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    After the publication of this work [1], we found that there were some mistakes in calculating the percentage of composition in Table 1(1). Clinicopathologic characteristics of breast cancer subtypes. We are therefore providing the revised Table 1, with the updated data for rows Mucinous carcinoma, Metaplastic carcinoma and Others. In the sub-content of Table 1, Histological type, the total number of Others was corrected from 18 to 16, and the composition of Others type was slightly changed according to breast cancer subtypes. For IHC-Her2 subtype, the number of Others was changed from 4 to 3, and 6 cases which were previously unidentified were assigned to corresponding subtypes. One case to IHC-BLBC, 2 cases to IHC-QNBC/5NP and 3 cases to IHC-TNCB. There was no effect on statistical analysis with the correction.

    Design of chimeric GLP-1A using oligomeric bile acids to utilize transporter-mediated endocytosis for oral delivery

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    Background Despite the effectiveness of glucagon-like peptide-1 agonist (GLP-1A) in the treatment of diabetes, its large molecular weight and high hydrophilicity result in poor cellular permeability, thus limiting its oral bioavailability. To address this, we developed a chimeric GLP-1A that targets transporter-mediated endocytosis to enhance cellular permeability to GLP-1A by utilizing the transporters available in the intestine, particularly the apical sodium-dependent bile acid transporter (ASBT). Methods In silico molecular docking and molecular dynamics simulations were used to investigate the binding interactions of mono-, bis-, and tetra-deoxycholic acid (DOCA) (monoDOCA, bisDOCA, and tetraDOCA) with ASBT. After synthesizing the chimeric GLP-1A-conjugated oligomeric DOCAs (mD-G1A, bD-G1A, and tD-G1A) using a maleimide reaction, in vitro cellular permeability and insulinotropic effects were assessed. Furthermore, in vivo oral absorption in rats and hypoglycemic effect on diabetic db/db mice model were evaluated. Results In silico results showed that tetraDOCA had the lowest interaction energy, indicating high binding affinity to ASBT. Insulinotropic effects of GLP-1A-conjugated oligomeric DOCAs were not different from those of GLP-1A-Cys or exenatide. Moreover, bD-G1A and tD-G1A exhibited improved in vitro Caco-2 cellular permeability and showed higher in vivo bioavailability (7.58% and 8.63%) after oral administration. Regarding hypoglycemic effects on db/db mice, tD-G1A (50 μg/kg) lowered the glucose level more than bD-G1A (50 μg/kg) compared with the control (35.5% vs. 26.4%). Conclusion GLP-1A was conjugated with oligomeric DOCAs, and the resulting chimeric compound showed the potential not only for glucagon-like peptide-1 receptor agonist activity but also for oral delivery. These findings suggest that oligomeric DOCAs can be used as effective carriers for oral delivery of GLP-1A, offering a promising solution for enhancing its oral bioavailability and improving diabetes treatment.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (grant nos. 2020R1A2C1102831, 2022R1A5A8033794, 2022R1A4A3034038). This study was also supported by Regional Innovation Strategy (RIS) through the NRF funded by the Ministry of Education (MOE) (2021RIS-001

    Neuronal Apoptosis Inhibitory Protein is Overexpressed in Patients with Unfavorable Prognostic Factors in Breast Cancer

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    Neuronal apoptosis inhibitory protein (NAIP) is a recently identified inhibitor of apoptosis protein. However, the clinical relevance of NAIP expression is not completely understood. In an attempt to determine the clinical relevance of NAIP expression in breast cancer, the levels of NAIP and survivin expression were measured in 117 breast cancer samples and 10 normal breast tissues using quantitative reverse-transcriptase-polymerase chain reaction. While there was no evidence of NAIP expression in the normal breast tissue, NAIP was expressed in all breast cancer samples. The level of NAIP expression in breast cancer was significantly higher (257 times) than in the universal tumor control. There was a strong correlation between the level of NAIP expression and the level of survivin expression (p=0.001). The level of NAIP expression in patients with a large tumor (≥T2) and patients with an unfavorable histology (nuclear grade III) was significantly higher than in those patients with a small tumor (T1) and patients with a favorable histology (nuclear grade I, II) (p=0.026 and p=0.050, respectively). Although the level of NAIP expression was higher in patients with other unfavorable prognostic factors, it was not significant. The three-year relapse-free survival rate was not significantly the patients showing high NAIP expression and patients showing low NAIP expression (86.47±4.79% vs. 78.74±6.57%). Further studies should include the expressions of NAIP in a larger number of patients and for a longer period of follow-up to evaluate correlation with metastasis and treatment outcome. In conclusion, NAIP is overexpressed in breast cancer patients with unfavorable clinical features such as stage and tumor size, suggesting that NAIP would play a role in the disease manifestation

    Favorable response to doxorubicin combination chemotherapy does not yield good clinical outcome in patients with metastatic breast cancer with triple-negative phenotype

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    <p>Abstract</p> <p>Background</p> <p>We analyzed the responses to first line treatment and clinical outcomes of metastatic breast cancer patients treated with palliative doxorubicin/cyclophosphamide (AC) according to molecular cancer subtype.</p> <p>Methods</p> <p>A retrospective analysis was performed for 110 metastatic breast cancer patients selected on the basis of palliative AC treatment and the availability of immunohistochemical data for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2/neu) status.</p> <p>Results</p> <p>Of the 110 patients analyzed, 71 (64.5%) were hormone receptor positive (HR+), 14 (12.7%) were HER2+, and 25 (22.7%) were triple negative (TN). There were no differences in age, stage at diagnosis, total number of cycles of palliative chemotherapy, incidence of visceral metastasis, and metastatic sites with the exception of liver among breast cancer subtypes. The overall response rates to AC were 55.9% for the HR+ subgroup, 42.9% for the HER2+ subgroup, and 56.5% for the TN subgroup. The progression-free survival (PFS) in patients with HER2+ and TN were significantly shorter than in the HR+ (median PFS, 9.1 <it>vs </it>8.1 <it>vs </it>11.5 months, respectively; p = 0.0002). The overall survival (OS) was 25.4 months in the TN subgroup and 27.3 months in HER2+ subgroup. The median OS for these two groups was significantly shorter than for patients in the HR+ subgroup (median, 38.5 months; 95% CI, 30.1-46.9 months; p < 0.0001).</p> <p>Conclusions</p> <p>The response to palliative AC chemotherapy did not differ among breast cancer subtypes. Despite chemosensitivity for palliative AC, the TN subtype has a shorter overall survival than non-TN subtypes. Innovative treatment strategies should be developed to slow the course of disease.</p
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