Functional electrolytes to improve electrochemical properties of cathodes and anodes in Na ion batteries

Department of Energy Engineering(Battery Science and Technology)As increasing importance of environment and demand of energy resources, energy devices have attracted a great deal of attention as facilitating smart grid system in society. Especially, large-scale electric energy storage (EES) which can store the electricity during times of excess production and release the electrical energy to the grid is reasonable way to save the energy resources. The Li-ion batteries which are one of successful energy devices show the possibility to application. However, the cost in large-scale ESS is the key issue for application because the cost of Li materials continuously increased. Recently, Na-ion batteries have been introduced as a promising candidate for next-generation battery systems because the natural abundance of Na resources. The Na materials have high benefit of the cost and it seem to suitable for large-scale ESS. Moreover, Na ion can easily apply Li-battery system due to the similarities with Li. Although Na-ion battery has many advantages for ESS, the large ionic size of sodium make it difficult to application. In this work, I demonstrate key aspects of the electrolyte formulation and additives to afford high electrochemical performances of Na4Fe3(PO4)2(P2O7) cathode and Sn4P3 anodes for Na-ion batteries. In the case of cathode, electrolytes are usually decomposed on electrode due to the high voltage and directly affect the electrochemical performance of cathode. However, I proposed that EC/PC-based electrolyte not only endure electrochemical decomposition in high voltage but also stable against the highly reactive Na metal. In case of anode, severe volume changes of the metallic anode by Na insertion and extraction cause cracking of the anode particles and lead to a continuous solid electrolyte interphase (SEI)-filming process on the exposed active surface of the anode. In Sn4P3, my investigation revealed that the FEC additive makes a resistive NaF-based SEI controlling the formation of Na15Sn4 phase with severe volume expansion and the TMSP additive effectively eliminated HF from the FEC decomposition to mitigate the formation of a large fraction of NaF and build up more stable and robust SEI layers. Furthermore, I demonstrate the surface chemistry of cathode and anode by using various analyses. This research can contribute to understand the interfacial characteristics and electrochemical reactions for Na-ion batteries.ope

Multi-functionalities of natural polysaccharide for enhancing electrochemical performance of macroporous Si anodes

Highly porous electrodes composed of natural polysaccharide act as a microporous binder and a carbon-coating source of micron-sized macroporous Si active materials was achieved. This highly porous Si-based anodes exhibit significantly improved electrochemical properties which show a high specific capacity (2010 mA h g-1) after 80 cycles.close1

Tissue expression and antibacterial activity of host defense peptides in chicken

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Host defence peptides are a diverse group of small, cationic peptides and are important elements of the first line of defense against pathogens in animals. Expression and functional analysis of host defense peptides has been evaluated in chicken but there are no direct, comprehensive comparisons with all gene family and individual genes. Results We examined the expression patterns of all known cathelicidins, β-defensins and NK-lysin in multiple selected tissues from chickens. CATH1 through 3 were predominantly expressed in the bone marrow, whereas CATHB1 was predominant in bursa of Fabricius. The tissue specific pattern of β-defensins generally fell into two groups. β-defensin1-7 expression was predominantly in bone marrow, whereas β-defensin8-10 and β-defensin13 were highly expressed in liver. NK-lysin expression was highest in spleen. We synthesized peptide products of these gene families and analysed their antibacterial efficacy. Most of the host defense peptides showed antibacterial activity against E.coli with dose-dependent efficacy. β-defensin4 and CATH3 displayed the strongest antibacterial activity among all tested chicken HDPs. Microscopic analyses revealed the killing of bacterium by disrupting membranes with peptide treatment. Conclusions These results demonstrate dose-dependent antimicrobial effects of chicken HDPs mediated by membrane damage and demonstrate the differential tissue expression pattern of bioactive HDPs in chicken and the relative antimicrobial potency of the peptides they encode

Recent Progress on Polymeric Binders for Silicon Anodes in Lithium-Ion Batteries

Advanced polymeric binders with unique functions such as improvements in the electronic conduction network, mechanical adhesion, and mechanical durability during cycling have recently gained an increasing amount of attention as a promising means of creating high-performance silicon (Si) anodes in lithium-ion batteries with high energy density levels. In this review, we describe the key challenges of Si anodes, particularly highlighting the recent progress in the area of polymeric binders for Si anodes in cellsopen

Comparison and analysis of the prevalence of hepatitis C virus infection by region in the Republic of Korea during 2005-2012

Background/AimsThis study compared the prevalence of hepatitis C virus (HCV) infection in the Republic of Korea and estimated the high-risk regions and towns.MethodsNational Health Insurance Service data for 8 years from 2005 to 2012 were used. The subjects of the study had visited medical facilities and been diagnosed with or received treatment for acute or chronic HCV as a primary or secondary disease according to ICD-10 codes of B17.1 or B18.2, respectively. Any patient who received treatment for the same disease multiple times during 1 year was counted as one patient in that year. To correct for the effect of the age structure of the population by year and region, the age-adjusted prevalence was calculated using the direct method based on the registered population in 2010.ResultsThe overall prevalence of HCV infection among Korean adults (>20 years old) increased from 0.14% in 2005 to 0.18% in 2012. The sex-, age-, and region-adjusted prevalence in 2012 was 0.18%. The prevalence was highest in Busan, Jeonnam, and Gyeongnam, and there were towns with noticeably higher prevalences within these regions: Jindo (0.97%) in Jeonnam, Namhae (0.90%) in Gyeongnam, and Seo-gu (0.86%) in Busan.ConclusionsThe prevalence of HCV infection differs by regions as well as towns in the Republic of Korea, and is highest in Busan, Jeonnam, and Gyeongnam. The reasons for the high prevalence in these specific regions should be identified, since this could help prevent HCV infections in the future. In addition, active surveillance and treatment policies should be introduced to stop any further spread of infection in these high-prevalence regions

Visuospatial memory impairment as a potential neurocognitive marker to predict tau pathology in Alzheimers continuum

Background Given that tau accumulation, not amyloid-β (Aβ) burden, is more closely connected with cognitive impairment in Alzheimers disease (AD), a detailed understanding of the tau-related characteristics of cognitive function is critical in both clinical and research settings. We investigated the association between phosphorylated tau (p-Tau) level and cognitive impairment across the AD continuum and the mediating role of medial temporal lobe (MTL) atrophy. We also developed a prediction model for abnormal tau accumulation. Methods We included participants from the Gwangju Alzheimers Disease and Related Dementia Cohort in Korea, who completed cerebrospinal fluid analysis and clinical evaluation, and corresponded to one of three groups according to the biomarkers of A and T profiles based on the National Institute on Aging and Alzheimers Association research framework. Multiple linear and logistic regression analyses were performed to examine the association between p-Tau and cognition and to develop prediction models. Receiver operating characteristic curve analysis was performed to examine the discrimination ability of the models. Results Among 185 participants, 93 were classified as A-T-, 23 as A+T-, and 69 as A+T+. There was an association between decreased visuospatial delayed memory performance and p-Tau level (B = − 0.754, β = − 0.363, p < 0.001), independent of other relevant variables (e.g., Aβ). MTL neurodegeneration was found to mediate the association between the two. Prediction models with visuospatial delayed memory alone (area under the curve [AUC] = 0.872) and visuospatial delayed memory and entorhinal thickness (AUC = 0.921) for abnormal tau accumulation were suggested and they were validated in an independent sample (AUC = 0.879 and 0.891, respectively). Conclusion It is crucial to identify sensitive cognitive measures that capture subtle cognitive impairment associated with underlying pathological changes. Preliminary findings from the current study might suggest that abnormal tau accumulation underlies episodic memory impairment, particularly visuospatial modality, in the AD continuum. Suggested models are potentially useful in predicting tau pathology, and might be utilized practically in the field.This study was supported by KBRI basic research program through Korea Brain Research Institute funded by Ministry of Science and ICT (21-BR-03-05), the Original Technology Research Program for Brain Science of the National Research Foundation (NRF) funded by the Korean government, MSIT (NRF-2014M3C7A1046041 and NRF-2016M3C7A1905469), the Brain Convergence Research Pro‑ gram of the NRF funded by the Ministry of Science and ICT (NRF2020M3E5D2A01084721) and a Basic Science Research Program through the NRF of Korea (NRF-2020R1F1A1052932

Early countermeasures to COVID-19 at long-term care facilities in Gwangju Metropolitan City, Republic of Korea

Objectives The coronavirus disease 2019 (COVID-19) pandemic has continued since its first detection in the Republic of Korea on January 20, 2020. This study describes the early countermeasures used to minimize the risk of COVID-19 outbreaks during cohort quarantine and compares the epidemiological characteristics of 2 outbreaks in long-term care facilities (LTCFs) in Gwangju Metropolitan City in summer 2020. Methods An epidemiological investigation was conducted via direct visits. We investigated epidemiological characteristics, including incidence, morbidity, and mortality rates, for all residents and staff members. Demographic characteristics were analyzed using a statistical program. Additionally, the method of managing infection in LTCFs is described. Results Residents and caregivers had high incidence rates in LTCF-A and LTCF-B, respectively. LTCF-B had a longer quarantine period than LTCF-A. The attack rate was 20.02% in LTCF-A and 27.9% in LTCF-B. The mortality rate was 2.3% (1/43) in LTCF-B, the only facility in which a COVID-19 death occurred. Conclusion Extensive management requires contact minimization, which involves testing all contacts to mitigate further transmission in the early stages of LTCF outbreaks. The findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks, particularly for early control in vulnerable facilities

A logical network-based drug-screening platform for Alzheimer’s disease representing pathological features of human brain organoids

Developing effective drugs for Alzheimer’s disease (AD), the most common cause of dementia, has been difficult because of complicated pathogenesis. Here, we report an efficient, network-based drug-screening platform developed by integrating mathematical modeling and the pathological features of AD with human iPSC-derived cerebral organoids (iCOs), including CRISPR-Cas9-edited isogenic lines. We use 1300 organoids from 11 participants to build a high-content screening (HCS) system and test blood–brain barrier-permeable FDA-approved drugs. Our study provides a strategy for precision medicine through the convergence of mathematical modeling and a miniature pathological brain model using iCOs. © 2021, The Author(s).1