163559 research outputs found
Sort by
Green Electrolytes for Aqueous Ion Batteries: Towards High-Energy and Low-Temperature Applications
No full textAqueous battery systems are increasingly recognized for their potential as environmentally friendly next-generation energy storage solutions. However, their commercialization faces challenges due to the need for electrolytes that can operate stably at high voltages and in low-temperatures. Traditional approaches to address these issues often involve materials that compromise the green nature. This review highlights the importance of developing environmentally friendly materials to improve the performance of aqueous electrolytes under high voltage in different types of aqueous electrolytes such as water-in-salt, molecular crowding electrolytes, eutectic electrolytes and cosolvents. In addition, we review advances in different types of aqueous electrolytes focused on using sustainable materials to achieve stable electrolytes at low-temperature by suppressing water crystallization and lowering the freezing point. By integrating these innovations, we envision a future where aqueous batteries offer both high performance and eco-friendliness, contributing significantly to the development of sustainable energy systems.N
Compound weather and climate extremes in the Asian region: science-informed recommendations for policy
No full textAnthropogenic climate change has led to rapid and widespread changes in the atmosphere, land, ocean, cryosphere, and biosphere, leading to more pronounced weather and climate extremes globally. Recent IPCC reports have highlighted that the probability of compound extreme events, which can amplify risk, has risen in multiple regions. However, significant gaps remain in our understanding of the drivers and mechanisms behind these events. This concept paper discusses compound events in the Asian region in the context of its unique and diverse geographical settings, and regional climatic features including the seasonal monsoons. Notably, Asia is the worlds most disaster-affected region due to weather, climate, and water-related hazards. Therefore, an integrated understanding of how climate change will impact compound events in this region is essential for effective forewarning and risk mitigation. This paper analyzes three typologies of compound events in the Asian region, illustrating their regional complexity and potential linkages to climate change. The first typology pertains to compound floods, for example, the devastating floods in the Indus River Basin and adjoining Western Himalayas during 2022 caused by the combined effects of heavy monsoon rainfall, intense pre-monsoon heatwaves, glacier melt, and modes of climate variability. The second typology relates to compound heatwave-drought events that have prominently manifested in East and South Asia, and are linked to large-scale drivers of the land-atmosphere–ocean coupled system and local feedbacks. The third typology relates to marine extremes involving the compounding effects of ocean warming, sea-level rise, marine heatwaves, and intensifying tropical cyclones. We identify key knowledge gaps in understanding and predicting compound events over the Asian region and discuss advances required in science and technology to address these gaps. We also provide recommendations for the effective utilization of climate information towards improving early warning systems and disaster risk reduction.Y
A Study on Adjective Collocational Competence of Chinese EFL Learners: Focusing on Big, Large and Great
No full textPolymer electrolyte membrane fuel cell durability test using ship operation profile: A comparative study with durability test protocols
No full textIn this study, we introduce and evaluate a novel accelerated durability test (ADT) protocol tailored for hydrogen fuel cells used in marine applications. Small research vessel (SRV) protocol, designed to mimic real vessel operations, is compared with the existing United States Department of Energy (DOE) and Swiss-based International Electrotechnical Commission (IEC) protocols over a 300-h period. The performance degradation of membrane-electrode assembly (MEA) is assessed through electrochemical analysis. Results indicate that the protocol based on the SRV profile offers a more realistic and balanced evaluation of fuel cell durability, being harsher than the DOE protocol but less severe than the IEC protocol. This study emphasizes the need for maritime-specific ADT protocols to ensure the long-term viability of hydrogen fuel cells in marine environments.N
Explainable vision transformer for automatic visual sleep staging on multimodal PSG signals
No full textPolysomnography (PSG) is crucial for diagnosing sleep disorders, but manual scoring of PSG is time-consuming and subjective, leading to high variability. While machine-learning models have improved PSG scoring, their clinical use is hindered by the 'black-box' nature. In this study, we present SleepXViT, an automatic sleep staging system using Vision Transformer (ViT) that provides intuitive, consistent explanations by mimicking human 'visual scoring'. Tested on KISS-a PSG image dataset from 7745 patients across four hospitals-SleepXViT achieved a Macro F1 score of 81.94%, outperforming baseline models and showing robust performances on public datasets SHHS1 and SHHS2. Furthermore, SleepXViT offers well-calibrated confidence scores, enabling expert review for low-confidence predictions, alongside high-resolution heatmaps highlighting essential features and relevance scores for adjacent epochs' influence on sleep stage predictions. Together, these explanations reinforce the scoring consistency of SleepXViT, making it both reliable and interpretable, thereby facilitating the synergy between the AI model and human scorers in clinical settings.Y
Surface-sensitive magneto-optical detection of nonequilibrium spins and orbitals
No full textThe magneto-optical effect provides a direct probing tool for angular momentum in materials and has been used to detect ferromagnetic orders. Notably, owing to its surface sensitivity, the magneto-optical Kerr effect has been extended to detect nonequilibrium spin and orbital accumulations in initially nonmagnetic materials. The spatial distribution and temporal dynamics of spins and orbitals provide key aspects of the generation, transport, and relaxation mechanisms. With an accurate determination of the magneto-optic constant for spin and orbital, a distinctive evaluation of the magnitude of the spin and orbital accumulation is possible. The magneto-optical Kerr effect also allows for the investigation of spin-orbit torque (SOT) in bilayers of nonmagnet and ferromagnet. The SOT enables a quantitative analysis of the generation and transport of spins and orbitals, and the orbital-to-spin conversion process. In this article, we review recent studies on magneto-optical detection of nonequilibrium spin and orbital accumulations in single layers of semiconductors and metals and SOT in bilayers including heavy metals, where spin generation is dominant, and light metals, where orbital generation is dominant.N
Dietary isoflavone intake among breast cancer survivors and cancer-free women
No full textBACKGROUND/OBJECTIVES: Isoflavones are estrogen-like compounds found in plants and their health effects remain equivocal. We investigated dietary isoflavone intake and its associated factors in Korean breast cancer survivors, with a comparison to cancer-free women. SUBJECTS/METHODS: The usual dietary intake of breast cancer survivors (n = 981, mean age 52 yrs) in 9 hospitals between 2012 and 2019 was assessed using 3-day food records or food frequency questionnaires (FFQs). They were age-matched to 2,943 cancer-free women who completed FFQs as part of a nationwide study conducted between 2012 and 2016. We used the flavonoid database of common Korean foods and the Phenol-Explorer database to estimate isoflavone intake. The contribution of each food or food group to the total isoflavone intake was calculated. The adjusted least-squares means of dietary isoflavone intake according to lifestyle and clinical factors were calculated using generalized linear models. RESULTS: Breast cancer survivors had a higher mean dietary isoflavone intake (23.59 mg/day) than cancer-free women (17.81 mg/day). Major food sources, including tofu, soybeans, and doenjang, contributed to over 70% of the isoflavone intake in both groups. When we estimated dietary isoflavone intake according to lifestyle characteristics, isoflavone intake increased with higher scores of adherence to the American Cancer Society dietary guidelines but decreased with increasing body mass index in both groups. Among cancer-free women, dietary isoflavone intake was higher among those who had never smoked and among dietary supplement users. Among breast cancer survivors, dietary isoflavone intakes did not vary with clinical characteristics, including time since surgery and estrogen receptor status. CONCLUSION: Breast cancer survivors were more likely to consume isoflavones than age- matched cancer-free women. Dietary isoflavone intake was associated with healthy lifestyle characteristics in women both with and without breast cancer. Further research is needed to understand the role of the higher isoflavone intake among breast cancer survivors compared to cancer-free women on their prognosis.Y
Structural insights into the role of reduced cysteine residues in SOD1 amyloid filament formation
No full textThe formation of superoxide dismutase 1 (SOD1) filaments has been implicated in amyotrophic lateral sclerosis (ALS). Although the disulfide bond formed between Cys57 and Cys146 in the active state has been well studied, the role of the reduced cysteine residues, Cys6 and Cys111, in SOD1 filament formation remains unclear. In this study, we investigated the role of reduced cysteine residues by determining and comparing cryoelectron microscopy (cryo-EM) structures of wild-type (WT) and C6A/C111A SOD1 filaments under thiol-based reducing and metal-depriving conditions, starting with protein samples possessing enzymatic activity. The C6A/ C111A mutant SOD1 formed filaments more rapidly than the WT protein. The mutant structure had a unique paired-protofilament arrangement, with a smaller filament core than that of the single-protofilament structure observed in WT SOD1. Although the single-protofilament form developed more slowly, cross-seeding experiments demonstrated the predominance of single-protofilament morphology over paired protofilaments, regardless of the presence of the Cys6 and Cys111 mutations. These findings highlight the importance of the number of amino acid residues within the filament core in determining the energy requirements for assembly. Our study provides insights into ALS pathogenesis by elucidating the initiation and propagation of filament formation, which potentially leads to deleterious amyloid filaments.Y
Clinical Significance of Incident Osteoporotic Fractures After Kidney Transplantation: A National Korean Cohort Study
No full textRationale & Objective: Recipients of kidney allografts are at risk of osteoporotic fractures (OF), but the association of OF with transplant patient outcomes remains uncertain due to common coexisting risks and complex medical conditions. This study sought to assess whether the overall incidences of OF among recipients of kidney allografts compared to that of patients receiving maintenance dialysis for kidney failure. Study Design: A national retrospective cohort study. Setting & Participants: 145,090 Korean patients newly diagnosed with kidney failure between 2009 and 2019. Exposure: Kidney transplantation versus dialysis resulting in OF, and OF increasing risk of death. Outcome: Incident OF overall and by site (hip, spine, forearm, and humerus); death. Analytical Approach: Comparison of patients receiving maintenance dialysis with recipients of kidney allografts matched by age, sex, year of new index date, duration of dialysis, and presence of hypertension and diabetes mellitus. Cause-specific Cox proportional hazards regression models estimated the association between modality of kidney replacement therapy and OF. Cox models incorporating OF as a time-updated covariate were used to estimate the association of OF and mortality. Results: A total of 11,413 pairs were matched. Over the entire study period, 541 (4.7%) OFs in allograft recipients and 657 (5.8%) in matched dialysis comparators occurred, respectively. After 5.5 years of follow-up evaluation, the risk of incident OF was lower in kidney transplant recipients compared with matched dialysis comparators (adjusted hazard ratio[AHR], 0.73 [95% CI, 0.64-0.84], P < 0.001). The differences in fracture rates were primarily driven by differences in hip fractures. Incident OF was associated with increased mortality risk (AHR, 2.18 [95% CI, 1.57-3.02], P < 0.001) and death-censored allograft failure (AHR, 1.42 [95% CI, 1.02-1.97], P = 0.040). Limitations: Use of claims data, and no data on bone mineral density or hyperparathyroidism; the definition of OF that was used encompassed traumatic fractures. Conclusions: Kidney allograft recipients have a lower rate of incident OF compared with dialysis patients, but when OF occurs it is associated with a higher rate of death and allograft loss.N
Laser-assisted synthesis and modification of 2D materials
No full textTwo-dimensional (2D) materials with unique physical, electronic, and optical properties have been intensively studied to be utilized for the next-generation electronic and optical devices, and the use of laser energy in the synthesis and modification of 2D materials is advantageous due to its convenient and fast fabrication processes as well as selective, controllable, and cost-effective characteristics allowing the precise control in materials properties. This paper summarizes the recent progress in utilizations of laser technology in synthesizing, doping, etching, transfer and strain engineering of 2D materials, which is expected to provide an insight for the future applications across diverse research areas.N