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금융데이터분석
No full text2024년 2학기 서울대학교 데이터사이언스대학원에서 강의한 금융데이터분석 (Financial Data Analysis) 과목의 강의 슬라이드를 모아서 출간한 것 (DATAlyLab Lecture Note Series
Mechanical-Stress-Induced Lithiation and Structural Evolution Driven by Excess Lithium Predisposing Short Circuits at the Surface of Garnet Solid Electrolytes
No full textCubic-garnet solid electrolyte has garnered significant attention in all-solid-state batteries (ASSBs) due to its ionic conductivity and chemical robustness against Li metal. However, the short-circuit formation at low current density poses a significant obstacle with the main cause remaining ambiguous. Here, the lithium-penetration mode originating from phase transformation is unveiled at the sintered pellet surface via mechanically induced lithiation. Mechanical stress applied during polishing under excess lithium content induces lithiation into the cubic-garnet structure, leading to partial structural evolution into the tetragonal phase. This surface alteration induces current constriction, hindered by sluggish interfacial Li-ion transport from the tetragonal phase, which exhibits low ionic conductivity, causing short circuits. By reducing mechanical stress, mitigating surface strain, and restoring the cubic phase, stable operation is ensured without short-circuit formation in both Li symmetric and hybrid-full cells. This insights illuminate the origin of lithium penetration related to phase transition at the surface of cubic-garnet and pave the way for enhancements in ASSB development.N
A phase III trial of adjuvant ribociclib plus endocrine therapy versus endocrine therapy alone in patients with HR-positive/HER2-negative early breast cancer: final invasive disease-free survival results from the NATALEE trial
No full textBackground: NATALEE assessed efficacy and tolerability of 3 years of adjuvant ribociclib plus a nonsteroidal aromatase inhibitor (NSAI) compared with an NSAI alone in a broad population of patients with hormone receptor (HR)-positive/human epidermal growth factor 2 (HER2)-negative early breast cancer, including a select group without nodal involvement. This is the final preplanned analysis of invasive disease-free survival (iDFS). Patients and methods: Premenopausal/postmenopausal women and men were randomized 1 : 1 to ribociclib (n = 2549; 400 mg/day, 3 weeks on/1 week off for 36 months) plus NSAI (letrozole 2.5 mg/day or anastrozole 1 mg/day for 60 months) or NSAI alone (n = 2552). Men and premenopausal women also received goserelin (3.6 mg once every 28 days). Patients had anatomical stage IIA (N0 with additional risk factors or N1), IIB, or III disease. The primary endpoint was iDFS. Secondary efficacy endpoints were recurrence-free survival (RFS), distant DFS, and overall survival. This final iDFS analysis was planned after ∼500 events. Results: At data cut-off (21 July 2023), ribociclib was stopped for 1996 patients (78.3%); 1091 (42.8%) completed 3 years of ribociclib, and ribociclib treatment was ongoing for 528 (20.7%). Median follow-up for iDFS was 33.3 months. Overall, 226 and 283 iDFS events occurred with ribociclib plus NSAI versus NSAI alone, respectively. Ribociclib plus NSAI demonstrated significant iDFS benefit over NSAI alone [hazard ratio 0.749, 95% confidence interval (CI) 0.628-0.892; P = 0.0012]. The 3-year iDFS rates were 90.7% (95% CI 89.3% to 91.8%) versus 87.6% (95% CI 86.1% to 88.9%). A consistent benefit was observed across prespecified subgroups, including stage (II/III) and nodal status (positive/negative). Distant DFS and RFS favored ribociclib plus NSAI. Overall survival data were immature. No new safety signals were observed. Conclusions: With longer follow-up and most patients off ribociclib, NATALEE continues to demonstrate iDFS benefit with ribociclib plus NSAI over NSAI alone in the overall population and across key subgroups. Observed adverse events remained stable.Y
Formononetin ameliorates DSS-induced colitis by inhibiting the MAPK/PPAR-γ/NF-κB/ROS signaling pathways
No full textBackground and aim: Formononetin (FMN) is a compound isolated from Astragalus membranaceus, that exhibits a range of pharmacological activities, including antitumor, anti-inflammatory, hypolipidemic, and antioxidant effects. Although preliminary study suggests that FMN have a therapeutic role in Inflammatory Bowel Disease (IBD), its specific mechanism of action requires further investigation. This study aimed to investigate the mechanism by which FMN treats DSS-induced colitis in mice. Methods: RAW264.7 and Bone marrow-derived macrophages (BMDMs) were treated with LPS to establish an inflammatory cell model. Biochemical parameters and morphological characteristics were assessed in the present or absent of FMN. 4 % solution of DSS was administered to C57BL/6 mice to induce IBD, which served as an animal model for investigating the pharmacodynamics of FMN. Results: FMN significantly reduced colitis-associated injury, as evidenced by a decrease in the disease activity index (DAI), weight gain, and restoration of colon length. Furthermore, FMN inhibits protein expression of NLRP3 inflammasome, suppressed the nuclear translocation of NF-κB/p65, and prevented mitochondrial damage, this process results in a reduction in the accumulation of reactive oxygen species (ROS). Additionally, FMN inhibited the mitogen-activated protein kinase (MAPK) signaling pathway, upregulated peroxisome proliferator-activated receptor gamma (PPAR-γ) in the nucleus, and decreased the release of inflammatory factors, thereby exerting anti-inflammatory effects. Conclusion: By inhibiting mitochondrial damage, activating the MAPK/PPAR-γ/ROS signaling pathway, reducing the nuclear translocation of NF-κB, and suppressing the expression of NLRP3 inflammasome-associated proteins, FMN exerts anti-inflammatory effects.N
Amplification of Northern Hemisphere winter stationary waves in a warming world
No full textThis study leverages the Global/Regional Integrated Model system (GRIMs) version 4.0 climate model to examine the mechanisms behind the recent intensification of winter stationary waves over western North America. Prescribed sea surface temperature warming forces a strengthening of westerly winds, amplifying the ridge that characterizes the stationary waves in western North America. The streamfunction budget analysis reveals relative vorticity advection is mainly associated with this process. We further show that ocean warming is the primary driver of changes in westerly winds and stationary waves in the Northern Hemisphere. Sea ice losses exert a considerable effect through a different mechanism, complementing the dominant influence of ocean warming on these atmospheric changes. Our results thus reveal the crucial role tropical oceans play in modulating global warming's effect on the stationary waves in the Northern Hemisphere and add a more quantitative perspective to the previously reported influence of Arctic amplification.N
Investigation of membrane-electrode assembly parameters for double-layer anion-exchange membrane-unitized regenerative fuel cell
No full textIn this study, we investigate various membrane-electrode assembly (MEA) parameters in the oxygen and hydrogen electrodes for high-efficiency anion-exchange membrane-unitized regenerative fuel cell (AEM_URFC). The effects of catalyst loadings, types of porous transport layer (PTL), and oxygen and hydrogen catalysts were optimized to improve the efficiency of the AEM_URFC. The PTL results indicated that the PTL suitable for fuel cell (FC) exhibited high round-trip efficiency (RTE). Additionally, the types of hydrogen electrode (Pt/C and PtRu/C) were examined. Additionally, AEM_URFCs with different oxygen reduction reaction (ORR) catalyst types (Pt/C and Pt black), and ORR and oxygen evolution reaction catalyst loadings were evaluated. Through our investigations, we developed a high-efficiency AEM_URFC with an RTE of 65.9 % at 20 mA cm−2 (0.871 and 1.572 V (FC and WE modes, respectively)). Moreover, the performance of this AEM_URFC is superior to that of other AEM_URFCs reported in the literature, which is attributed to the reduced ohmic resistance loss caused by the electrical conductivity and hydrophobicity of carbon PTL. Moreover, the AEM_URFC was durable for 5 cycles, indicating that it is cyclable under URFC operation.N
Pembrolizumab and chemotherapy in high-risk, early-stage, ER<SUP>+</SUP>/HER2<SUP>-</SUP> breast cancer: a randomized phase 3 trial
No full textAddition of pembrolizumab to neoadjuvant chemotherapy followed by adjuvant pembrolizumab improved outcomes in patients with high-risk, early-stage, triple-negative breast cancer. However, whether the addition of neoadjuvant pembrolizumab to chemotherapy would improve outcomes in high-risk, early-stage, estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer remains unclear. We conducted a double-blind, placebo-controlled phase 3 study (KEYNOTE-756) in which patients with previously untreated ER+/HER2- grade 3 high-risk invasive breast cancer (T1c-2 (>= 2 cm), cN1-2 or T3-4, cN0-2) were randomly assigned (1:1) to neoadjuvant pembrolizumab 200 mg or placebo Q3W given with paclitaxel QW for 12 weeks, followed by four cycles of doxorubicin or epirubicin plus cyclophosphamide Q2W or Q3W. After surgery (with/without adjuvant radiation therapy), patients received adjuvant pembrolizumab or placebo for nine cycles plus adjuvant endocrine therapy. Dual primary endpoints were pathological complete response and event-free survival in the intention-to-treat population. In total, 635 patients were assigned to the pembrolizumab-chemotherapy arm and 643 to the placebo-chemotherapy arm. At the study's prespecified first interim analysis, the pathological complete response rate was 24.3% (95% confidence interval (CI), 21.0-27.8%) in the pembrolizumab-chemotherapy arm and 15.6% (95% CI, 12.8-18.6%) in the placebo-chemotherapy arm (estimated treatment difference, 8.5 percentage points; 95% CI, 4.2-12.8; P = 0.00005). Event-free survival was not mature in this analysis. During the neoadjuvant phase, treatment-related adverse events of grade >= 3 were reported in 52.5% and 46.4% of patients in the pembrolizumab-chemotherapy and placebo-chemotherapy arms, respectively. In summary, the addition of pembrolizumab to neoadjuvant chemotherapy significantly improved the pathological complete response rate in patients with high-risk, early-stage ER+/HER2- breast cancer. Safety was consistent with the known profiles of each study treatment. Follow-up continues for event-free survival. ClinicalTrials.gov identifier: NCT03725059.Y
Volcanically forced Madden-Julian oscillation triggers the immediate onset of El Niño
No full textA process-level understanding of the volcanically forced climate response is an urgent challenge due to its similarities to the potential effects of geoengineering techniques. Although the influence of volcanic forcing on El Ni & ntilde;o events has been studied extensively, the mechanisms driving the volcanically-induced immediate onset of El Ni & ntilde;o remain uncertain, with many climate models producing a delayed El Ni & ntilde;o response compared to observations. In this study, using large ensemble simulations that allow us to isolate the impacts of volcanic forcing on the El Ni & ntilde;o response, we demonstrate a mechanism that highlights the central triggering role of the Madden-Julian oscillation (MJO), which has been overlooked in existing literature. Because the land areas surrounding the Indo-Pacific warm pool dry more quickly after a volcanic eruption, the background moisture distribution becomes more favorable for the MJO to propagate eastward from the Indian Ocean into the Pacific. This increases the likelihood of ensemble members having stronger MJO activity in the western Pacific by about 35% compared to non-volcanic years, which subsequently increases the frequency of westerly wind bursts by about 76%, ultimately enhancing the probability of the onset of an El Ni & ntilde;o by about 98% following major volcanic eruptions.Y
신재생발전기 송전계통연계 기술기준에 따른 무효전력 보상량 산정에 관한 연구
No full textAs interest in renewable energy grows due to the climate crisis, large-scale offshore wind farms are emerging as a key solution for achieving carbon neutrality. These farms can overcome the spatial and noise limitations of onshore wind; however, their intermittent nature and integration into high-voltage grids pose challenges to grid stability due to power output fluctuations. Therefore, an analysis is required for the grid connection of offshore wind farms. This paper examines reactive power compensation in accordance with the technical standards for the grid integration of offshore wind farms and calculates the required capacities for reactors and STATCOM based on the reactive power compensation strategy. Using PSS/E simulations, an offshore wind farm model was developed, and the necessary reactive power compensation was calculated.N
