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Seongmin Kim,Hanseul Kim,Sung Wook Doo,Hee-Jae Jeon,In Hye Kim,Hyun-seung Kim,Youngjin Kim The Korean Electrochemical Society 2023 Journal of electrochemical science and technology Vol.14 No.3
The global energy storage markets have gravitated to high-energy-density and low cost of lithium-ion batteries (LIBs) as the predominant system for energy storage such as electric vehicles (EVs). High-Ni layered oxides are considered promising next-generation cathode materials for LIBs owing to their significant advantages in terms of high energy density. However, the practical application of high-Ni cathodes remains challenging, because of their structural and surface instability. Although extensive studies have been conducted to mitigate these inherent instabilities, a two-step process involving the synthesis of the cathode and a dry/wet coating is essential. This study evaluates a one-step β-Li<sub>2</sub>SnO<sub>3</sub> layer coating on the surface of LiNi<sub>0.8</sub>Co<sub>0.2</sub>O<sub>2</sub> (NC82) via the thermal segregation of Sn owing to the solubility limit with respect to the synthesis temperature. The doping, segregation, and phase transition of Sn were systematically revealed by structural analyses. Moreover, surface-engineered 5 mol% Sn-coated LiNi<sub>0.8</sub>Co<sub>0.2</sub>O<sub>2</sub> (NC82_Sn5%) exhibited superior capacity retention compared to bare NC82 owing to the stable surface coating layer. Thus, the developed one-step coating method is suitable for improving the properties of high-Ni layered oxide cathode materials for application in LIBs.
Kim, Jin,Kim, C-yoon,Oh, Hanseul,Ryu, Bokyeong,Kim, Ukjin,Lee, Ji Min,Jung, Cho-Rok,Park, Jae-Hak Elsevier 2019 The Science of the total environment Vol.653 No.-
<P><B>Abstract</B></P> <P>Trimethyltin chloride (TMT), one of the most widely used organotin compounds in industrial and agricultural fields, is widespread in soil, aquatic systems, foodstuffs and household items. TMT reportedly has toxic effects on the nervous system; however, there is limited information about its effects on eye development and no clear associated mechanisms have been identified. Therefore, in the present study, we investigated eye morphology, vison-related behavior, reactive oxygen species (ROS) production, apoptosis, histopathology, and gene expression to evaluate the toxicity of TMT during ocular development in zebrafish embryos. Exposure to TMT decreased the axial length and surface area of the eye and impaired the ability of zebrafish to recognize light. 2′,7′-dichlorofluorescein diacetate and acridine orange assays revealed dose-dependent increases in ROS formation and apoptosis in the eye. Furthermore, pyknosis of retinal cells was confirmed through histopathological analysis. Antioxidative enzyme-related genes were downregulated and apoptosis-inducing genes were upregulated in TMT-treated zebrafish compared to expression in controls. Retinal cell-specific gene expression was suppressed mainly in retinal ganglion cells, bipolar cells, and photoreceptor cells, whereas amacrine cell-, horizontal cell-, and Müller cell-specific gene expression was enhanced. Our results demonstrate for the first time the toxicity of TMT during eye development, which occurs through the induction of ROS-mediated apoptosis in retinal cells during ocular formation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TMT causes microphthalmia and impairs visual function in zebrafish embryo. </LI> <LI> TMT induces dose-dependent increases in ROS formation and apoptosis in the eye. </LI> <LI> TMT is toxic to specific retinal cells and leads histopathological abnormalities. </LI> <LI> TMT affected the expression of genes related to above changes. </LI> <LI> This is the first study to confirm the ocular developmental toxicity of TMT. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Hee Joong,Kim, Youngjin,Shim, Jimin,Jung, Kyung Hwa,Jung, Min Soo,Kim, Hanseul,Lee, Jong-Chan,Lee, Kyu Tae American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.4
<P>Na-ion batteries are attractive as an alternative to Li-ion batteries because of their lower cost. Organic compounds have been considered as promising electrode materials due to their environmental friendliness and molecular diversity. Herein, aluminum-coordinated poly(tetrahydroxybenzoquinone) (P(THBQ-Al)), one of the coordination polymers, is introduced for the first time as a promising cathode for Na-ion batteries. P(THBQ-Al) is synthesized through a facile coordination reaction between benzoquinonedihydroxydiolate (C6O6H22-) and Al3+ as ligands and complex metal ions, respectively. Tetrahydroxybenzoquinone is environmentally sustainable, because it can be obtained from natural resources such as orange peels. Benzoquinonedihydroxydiolate also contributes to delivering high reversible capacity, because each benzoquinonedihydroxydiolate unit is capable of two electron reactions through the sodiation of its conjugated carbonyl groups. Electrochemically inactive Al3+ improves the structural stability of P(THBQ-Al) during cycling because of a lack of a change in its oxidation state. Moreover, P(THBQ-Al) is thermally stable and insoluble in nonaqueous electrolytes. These result in excellent electrochemical performance including a high reversible capacity of 113 mA h g(-1) and stable cycle performance with negligible capacity fading over 100 cycles. Moreover, the reaction mechanism of P(THBQ-Al) is clarified through ex situ XPS and IR analyses, in which the reversible sodiation of C=O into C-O-Na is observed.</P>
( Hanseul Oh ),( C Yoon Kim ),( Chang Hwan Kim ),( Gyeung Haeng Hur ),( Jae Hak Park ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.9
Francisella tularensis is a highly virulent pathogen of humans and other mammals. Moreover, F. tularensis has been designated a category A biothreat agent, and there is growing interest in the development of a protective vaccine. In the present study, we determine the in vitro and in vivo immune responses of a subunit vaccine composed of recombinant peptides Tul4 and FopA from epitopes of the F. tularensis outer membrane proteins. The recombinant peptides with adjuvant CpG induced robust immunophenotypic change of dendritic cell (DC) maturation and secretion of inflammatory cytokines (IL-6, IL-12). In addition, the matured DCs enabled ex vivo proliferation of naive splenocytes in a mixed lymphocyte reaction. Lastly, we determined the in vivo immune response by assessment of antibody production in C57BL/ 6 mice. Total IgG levels were produced after immunization and peaked in 6 weeks, and moreover, Tul4-specific IgG was confirmed in the mice receiving peptides with or without CpG. Based on these results, we concluded that the recombinant peptides Tul4 and FopA have immunogenicity and could be a safe subunit vaccine candidate approach against F. tularensis.
Kim, Hanseul,Choi, Aram,Doo, Sung Wook,Lim, Jungwoo,Kim, YoungJin,Lee, Kyu Tae The Electrochemical Society 2018 Journal of the Electrochemical Society Vol.165 No.2
<P>LiNiO2 is a promising cathode material for lithium ion batteries because of its high specific capacity (approximately 220 mA h g(-1)). However, there are several challenging issues in the development of LiNiO2, including its poor cycle and rate performance because of its structural deterioration due to thermodynamically unstable Ni3+. This paper demonstrates the role of Na+ in the electrochemical performance and structural stability of [Li1-xNax]NiO2 (x = 0, 0.005, 0.01, 0.025, and 0.05). Charge disproportionation Ni3+. Ni2+ and Ni4+ in LiNiO2 increases the cation mixing of Li+ and Ni2+ during cycling, resulting in the poor cycle performance of LiNiO2. However, Na+ in [Li1-xNax]NiO2 mitigates the charge disproportionation because of the larger size of Na+ than Li+, leading to the improved structural stability of [Li1-xNax]NiO2. Consequently, Na+-doped LiNiO2 alleviates the increase in the cation mixing of Li+ and Ni2+ during cycling compared to bare LiNiO2. This results in the improved cycle performance of [Li1-xNax]NiO2 (x = 0.05), such as approximately 76% of capacity retention after 100 cycles. Moreover, the substitution of Li+ with Na+ in LiNiO2 improves the storage characteristics of [Li1-xNax]NiO2, leading to a negligible capacity loss even after long-term storage. (c) 2018 The Electrochemical Society.</P>
Kim, C-Yoon,Hwang, In-Kyu,Kang, Changhee,Chung, Eun-Bin,Jung, Cho-Rok,Oh, Hanseul,Jeong, Young-Hoon,Moon, Sung-Hwan,Kim, Jong Soo,Hong, Ki-Sung,Park, Jae-Hak,Chung, Hyung-Min Korean Society for Stem Cell Research 2018 International journal of stem cells Vol.11 No.2
<P>Human embryonic stem cells (hESCs) are pluripotent cells widely used in conventional and regenerative medicine due to their ability to self-renew, proliferate and differentiate. Recently, genetic modification of stem cells using genome editing is the most advanced technique for treating hereditary diseases. Nevertheless, the low transfection efficiency of hESCs using enzymatic methods is still limited in <I>in vitro</I> preclinical research. To overcome these limitations, we have developed transfection methods using non-enzymatic treatments on hESCs. In this study, hESCs were transfected following enzymatic (TrypLE and trypsin) and non-enzymatic treatment ethylenediaminetetraacetic acid (EDTA) to increase transfection efficiency. Flow cytometric analysis using an enhanced green fluorescent protein vector showed a significantly increased transfection efficiency of EDTA method compared to standard enzyme method. In addition, the EDTA approach maintained stable cell viability and recovery rate of hESCs after transfection. Also, metabolic activity by using Extracellular Flux Analyzer revealed that EDTA method maintained as similar levels of cell functionality as normal group comparing with enzymatic groups. These results suggest that transfection using EDTA is a more efficient and safe substitute for transfection than the use of standard enzymatic methods.</P>
Kim, Jin,Oh, Hanseul,Ryu, Bokyeong,Kim, Ukjin,Lee, Ji Min,Jung, Cho-Rok,Kim, C-yoon,Park, Jae-Hak Elsevier 2018 Environmental pollution Vol.236 No.-
<P><B>Abstract</B></P> <P>Triclosan (TCS) is an organic compound with a wide range of antibiotic activity and has been widely used in items ranging from hygiene products to cosmetics; however, recent studies suggest that it has several adverse effects. In particular, TCS can be passed to both fetus and infants, and while some evidence suggests <I>in vitro</I> neurotoxicity, there are currently few studies concerning the mechanisms of TCS-induced developmental neurotoxicity. Therefore, this study aimed to clarify the effect of TCS on neural development using zebrafish models, by analyzing the morphological changes, the alterations observed in fluorescence using HuC-GFP and Olig2-dsRED transgenic zebrafish models, and neurodevelopmental gene expression. TCS exposure decreased the body length, head size, and eye size in a concentration-dependent manner in zebrafish embryos. It increased apoptosis in the central nervous system (CNS) and particularly affected the structure of the CNS, resulting in decreased synaptic density and shortened axon length. In addition, it significantly up-regulated the expression of genes related to axon extension and synapse formation such as <I>α1-Tubulin</I> and <I>Gap43</I>, while decreasing <I>Gfap</I> and <I>Mbp</I> related to axon guidance, myelination and maintenance. Collectively, these changes indicate that exposure to TCS during neurodevelopment, especially during axonogenesis, is toxic. This is the first study to demonstrate the toxicity of TCS during neurogenesis, and suggests a possible mechanism underlying the neurotoxic effects of TCS in developing vertebrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TCS changes craniofacial morphology and neural structures in zebrafish embryos. </LI> <LI> TCS affects the expression of apoptosis and neurogenesis related genes. </LI> <LI> TCS is toxic to neurodevelopmental stages, especially in axonogenesis. </LI> <LI> This is the first study to confirm the developmental neurotoxicity of TCS. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>