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Liquid metal arene complex for next-generation batteriesby Ji-Su Woo;Hyun-Wook Lee;Ji-Hee Lee;Seung-Hun Han;Won-Jin KwakMaterials Today Energy 2023, 30, 101156; https://doi.org/10.1016/j.mtener.2022.101156 AbstractLithium metal batteries have received attention as next-generation systems owing to their high energy density compared to that of commercial lithium-ion batteries. However, low stability and cycle life with dendrite growth hinder the practical application of metal anodes. To conquer these limitations, studies utilizing dendrite-free liquid-phase anodes, such as liquid metal and liquid metal arene complexes (LMACs), have been conducted. LMAC is more controllable and stable than liquid metal; therefore, the use of LMAC has been recently investigated in various systems. Herein, a detailed overview of LMAC including the principle and characteristics has been provided. Additionally, based on recent research utilizing LMAC as an anode or a lithiation source, obstacles limiting the practical application of LMAC along with future research directions are discussed. Keywords: Next-generation batteriesLiquid electrodesLiquid metal arene complexesLithiationRecycling
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Delocalization and re-entrant localization of flat-band states in non-Hermitian disordered lattice models with flat bands by Sangbum Kim;Kihong Kim Progress of Theoretical and Experimental Physics 2023 2023(1); https://doi.org/10.1093/ptep/ptac162 Abstract We present a numerical study of Anderson localization in disordered non-Hermitian lattice models with flat bands. Specifically, we consider 1D stub and 2D kagome lattices that have a random scalar potential and a uniform imaginary vector potential and calculate the spectra of the complex energy, the participation ratio, and the winding number as a function of the strength of the imaginary vector potential, h. The flat-band states are found to show a double transition from localized to delocalized and back to localized states with h, in contrast to the dispersive-band states going through a single delocalization transition. When h is sufficiently small, all flat-band states are localized. As h increases above a certain critical value h1, some pairs of flat-band states become delocalized. The participation ratio associated with them increases substantially and their winding numbers become nonzero. As h increases further, more and more flat-band states get delocalized until the fraction of the delocalized states reaches a maximum. For larger h values, a re-entrant localization takes place and, at another critical value h2, all flat-band states return to compact localized states with very small participation ratios and zero winding numbers. This re-entrant localization transition, which is due to the interplay among disorder, non-hermiticity, and the flat band, is a phenomenon occurring in many models having an imaginary vector potential and a flat band simultaneously. We explore the spatial characteristics of the flat-band states by calculating the local density distribution.
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Giant overreflection of magnetohydrodynamic waves from inhomogeneous plasmas with nonuniform shear flows by Seulong Kim;Kihong Kim Physics of Fluids 2022, 34(12); https://doi.org/10.1063/5.0127265 Abstract We theoretically study mode conversion and resonant overreflection of magnetohydrodynamic waves in an inhomogeneous plane-stratified plasma in the presence of a nonuniform shear flow using precise numerical calculations of the reflection and transmission coefficients and the field distributions based on the invariant imbedding method. Cases where the flow velocity and the external magnetic field are directed perpendicularly to the inhomogeneity direction and both the flow velocity and the plasma density vary arbitrarily along it are considered. When there is a shear flow, the wave frequency is modulated locally by the Doppler shift, and resonant amplification and overreflection occur where the modulated frequency is negative and its absolute value matches the local Alfvén or slow frequency. For many different types of the density and flow velocity profiles, we find that, especially when the parameters are such that the incident waves are totally reflected, there arises a giant overreflection where the reflectance is much larger than 10 in a fairly broad range of the incident angles, the frequency, and the plasma β, and its maximum attains values larger than 105. In a finite β plasma, both incident fast and slow magnetosonic waves are found to cause strong overreflection and there appear multiple positions exhibiting both Alfvén and slow resonances inside the plasma. We explain the mechanism of overreflection in terms of the formation of inhomogeneous and open cavities close to the resonances and the strong enhancement of the wave energy due to the occurrence of semi-bound states there. We discuss the observational consequences in magnetized terrestrial and solar plasmas.
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Two-Photon Fluorescent Probes for Quantitative Bio-Imaging Analysis in Live Tissues by Vinayak Juvekar;Hyo Won Lee;Dong Joon Lee;Hwan Myung Kim TRAC-TRENDS IN ANALYTICAL CHEMISTRY 2022, 157(0); https://doi.org/10.1016/j.trac.2022.116787 Abstract Two-photon (TP) microscopy (TPM) is an indispensable visualization tool for deep-tissue imaging. TPM uses the low energy light of the near-infrared window as an excitation source of fluorophores which reduces autofluorescence, photodamage, and light scattering, resulting in high resolution fluorescence images potentially beyond several millimeter depths in living systems. Due to the continuous development of the microscope and advances in optical output algorithms, it is crucial to develop innovative strategies for the quantitative analysis of biomedically relevant target analytes in living systems using TP fluorescence probes. In this review, we have highlighted ratiometric TP probe design strategies with representative ratiometric TP sensors in the last decade. We have also summarized the recent progress in the development of TP probes published between 2017 and 2022 for quantitatively detecting analytes such as enzymes, reactive species, bio-thiols, pH, neutral molecules, and metal ions in live cells and tissues. Keywords: Bio-imagingQuantitative analysisTwo-photon probesTissue imagingTwo-photon microscopy
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Cytoplasmic molecular chaperones in Pseudomonas species. by Hyunhee Kim;Seongjoon Moon;Soojeong Ham;Kihyun Lee;Ute Römling;Changhan Lee Journal of Microbiology 2022, 60(0); https://doi.org/10.1007/s12275-022-2425-0 Abstract Pseudomonas is widespread in various environmental and host niches. To promote rejuvenation, cellular protein homeostasis must be finely tuned in response to diverse stresses, such as extremely high and low temperatures, oxidative stress, and desiccation, which can result in protein homeostasis imbalance. Molecular chaperones function as key components that aid protein folding and prevent protein denaturation. Pseudomonas, an ecologically important bacterial genus, includes human and plant pathogens as well as growth-promoting symbionts and species useful for bioremediation. In this review, we focus on protein quality control systems, particularly molecular chaperones, in ecologically diverse species of Pseudomonas, including the opportunistic human pathogen Pseudomonas aeruginosa, the plant pathogen Pseudomonas syringae, the soil species Pseudomonas putida, and the psychrophilic Pseudomonas antarctica.
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A Method to Study α-Synuclein Toxicity and Aggregation Using a Humanized Yeast Model by Hyunhee Kim;Juwon Jeong;Changhan Lee Journal of Visualized Experiments 2022, 189(0); https://doi.org/10.3791/64418 Abstract Parkinson's disease is the second most common neurodegenerative disorder and is characterized by progressive cell death caused by the formation of Lewy bodies containing misfolded and aggregated α-synuclein. α-synuclein is an abundant presynaptic protein that regulates synaptic vesicle trafficking, but the accumulation of its proteinaceous inclusions results in neurotoxicity. Recent studies have revealed that various genetic factors, including bacterial chaperones, could reduce the formation of α-synuclein aggregates in vitro. However, it is also important to monitor the anti-aggregation effect in the cell to apply this as a potential treatment for the patients. It would be ideal to use neuronal cells, but these cells are difficult to handle and take a long time to exhibit the anti-aggregation phenotype. Therefore, a quick and effective in vivo tool is required for the further evaluation of in vivo anti-aggregation activity. The method described here was used to monitor and analyze the anti-aggregation phenotype in the humanized yeast Saccharomyces cerevisiae, which expressed human α-synuclein. This protocol demonstrates in vivo tools that could be used for monitoring α-synuclein-induced cellular toxicity, as well as the formation of α-synuclein aggregates in cells. ,
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Advances in Small Molecule Two-Photon Fluorescent Trackers for Lipid Droplets in Live Sample Imaging by Dong Joon Lee;Eun Seo Kim;Hyo Won Lee;Hwan Myung Kim Frontiers in Chemistry 2022, 10(0); https://doi.org/10.3389/fchem.2022.1072143 Abstract Two-photon fluorescent trackers for monitoring of lipid droplets (LDs) would be highly effective for illustrating the critical roles of LDs in live cells or tissues. Although a number of one-photon fluorescent trackers for labeling LDs have been developed, their usability remains constrained in live sample imaging due to photo damage, shallow imaging depth, and auto-fluorescence. Recently, some two-photon fluorescent trackers for LDs have been developed to overcome these limitations. In this mini-review article, the advances in two-photon fluorescent trackers for monitoring of LDs are summarized. We summarize the chemical structures, two-photon properties, live sample imaging, and biomedical applications of the most recent representative two-photon fluorescent trackers for LDs. Additionally, the current challenges and future research trends for the two-photon fluorescent trackers of LDs are discussed.
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Recent Advances in Biosensor Technologies for Point-of-Care Urinalysis by Chuljin Hwang;Won-June Lee;Su Dong Kim;Sungjun Park;Joo Hee Kim Biosensors 2022, 12(11); https://doi.org/10.3390/bios12111020 Abstract Human urine samples are non-invasive, readily available, and contain several components that can provide useful indicators of the health status of patients. Hence, urine is a desirable and important template to aid in the diagnosis of common clinical conditions. Conventional methods such as dipstick tests, urine culture, and urine microscopy are commonly used for urinalysis. Among them, the dipstick test is undoubtedly the most popular owing to its ease of use, low cost, and quick response. Despite these advantages, the dipstick test has limitations in terms of sensitivity, selectivity, reusability, and quantitative evaluation of diseases. Various biosensor technologies give it the potential for being developed into point-of-care (POC) applications by overcoming these limitations of the dipstick test. Here, we present a review of the biosensor technologies available to identify urine-based biomarkers that are typically detected by the dipstick test and discuss the present limitations and challenges that future development for their translation into POC applications for urinalysis. Keywords: urine sensor; point-of-care urinalysis; clinical application for urinalysis; dipstick test; biosensors
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[논문] 김상범, 김기홍 - Delocalization and re-entrant localization of flat-band states in non-Hermitian disordered lattice model 위치 확인