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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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36
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- 작성일2023-01-16
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34
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- 작성일2023-01-16
- 615
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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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- 작성일2023-01-16
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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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- 작성일2023-01-16
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Enhancing the oxidation resistance of nanocrystalline high-entropy AlCuCrFeMn alloys by the addition of tungsten by Sheetal Kumar Dewangan;Devesh Kumar; Ashutosh Sharma;Byungmin Ahn;Vinod Kumar Journal of Materials Research and Technology-JMR&T 2022, 21(0); https://doi.org/10.1016/j.jmrt.2022.11.078 Abstract The isothermal oxidation behavior of multi-component high entropy alloys (HEAs), namely AlCuCrFeMn, AlCuCrFeMnW0.05, AlCuCrFeMnW0.1, and AlCuCrFeMnW0.5, was investigated and the behavior of the oxide layer was analyzed. All four HEAs were synthesized via mechanical alloying (MA) and consolidated by spark plasma sintering (SPS). The samples were oxidized in the air atmosphere at a temperature of 500 °C for 50 h. Based on the thermogravimetric result, the oxidation rate of the materials decreased with the increase of W content, and the values of parabolic constants were on a level similar to those observed in Ni–Al superalloys. However, higher content of W improves the continuity and internal position of the WO3 scale, which leads to increased oxidation resistance. Throughout the oxidation process, the composition of the phases of all materials changed significantly. The triple-thick oxide layer formed of Al2O3, Cr2O3, and WO3, developed in HEAs, has been carefully studied using the XPS technique. Keywords: High-entropy alloyOxide resistanceNanocrystallinePowder metallurgy
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- 작성일2023-01-16
- 623
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- 작성일2023-01-16
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Quasiresonant diffusion of wave packets in one-dimensional disordered mosaic lattices by Ba Phi Nguyen;Duy Khuong Phung;Kihong Kim Physical Review B 2022, 106(13); https://doi.org/10.1103/PhysRevB.106.134204 Abstract We investigate numerically the time evolution of wave packets incident on one-dimensional semi-infinite lattices with mosaic modulated random on-site potentials, which are characterized by the integer-valued modulation period κ and the disorder strength W. For Gaussian wave packets with the central energy E0 and a small spectral width, we perform extensive numerical calculations of the disorder-averaged time-dependent reflectance, 〈R(t)〉, for various values of E0, κ, and W. We find that the long-time behavior of 〈R(t)〉 obeys a power law of the form t−γ in all cases. In the presence of the mosaic modulation, γ is equal to 2 for almost all values of E0, implying the onset of the Anderson localization, while at a finite number of discrete values of E0 dependent on κ, γ approaches 3/2, implying the onset of the classical diffusion. This phenomenon is independent of the disorder strength and arises in a quasiresonant manner such that γ varies rapidly from 3/2 to 2 in a narrow energy range as E0 varies away from the quasiresonance values. We deduce a simple analytical formula for the quasiresonance energies and provide an explanation of the delocalization phenomenon based on the interplay between randomness and band structure and the node structure of the wave functions. We explore the nature of the states at the quasiresonance energies using a finite-size scaling analysis of the average participation ratio and find that the states are neither extended nor exponentially localized, but critical states.
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- 작성일2023-01-16
- 664
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Development of the adaptive pattern synthesis method for accurate structured illumination by InYoung Park;Jonghee Yoon Optics and Lasers in Engineering 2022, 161(0); https://doi.org/10.1016/j.optlaseng.2022.107342 Abstract Structured illumination, which projects a predefined spatially varying intensity pattern, has been widely used in a variety of applications, including 3D shape estimation, optical property estimation, and super-resolution imaging. The precision of the structured illumination method is determined by the accuracy of the illumination pattern captured by the detector; however, acquiring images of the precise pattern is difficult due to distortion and nonlinear response in the imaging system. We proposed an adaptive pattern synthesis method that could overcome projecting system distortion and the system's nonlinear response. The proposed method consists of four steps: estimation of the geometric transformation matrix between the structured illumination unit and detector, estimation of the detector's intensity lookup table, and synthesis of the corrected patterns. Furthermore, by measuring the 3D printed target and tissue-mimicking phantom, the proposed method demonstrated its ability to improve the accuracy of phase shift profilometry and spatial frequency domain imaging. It does not require fine alignment or optical system details because all procedure is performed by projecting digital patterns and its measurement without calibration targets. The proposed method could be applied to any optical technique that uses structured illumination to improve accuracy and performance, making it useful in both academic and industrial applications. Keywords Structured illuminationSpatial frequency domain imagingPhase shift profilometryAdaptive opticsPattern correction
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- 작성일2023-01-16
- 624
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Surface activated zinc-glutarate for the copolymerization of CO2 and epoxides by Yongmoon Yang;Jong Doo Lee;Yeong Hyun Seo;Ju-Hyung Chae;Sohee Bang;Yeon-Joo Cheong;Bun Yeoul Lee;In-Hwan Lee;Seung Uk Son;Hye-Young Jang Dalton Transactions 2022, 51(0); https://doi.org/10.1039/D2DT03007A Abstract Zinc-glutarate (ZnGA) is a promising catalyst that can form polymers from CO2 and epoxides, thereby contributing to the development of CO2 utilization technologies and future sustainability. One of the obstacles to commercializing ZnGA in polymer industries is its low catalytic activity. In this study, we introduced activated two-dimensional (2D) ZnGA to improve its catalytic activity in polymerization. The morphology-controlled 2D ZnGA was treated with H3Co(CN)6, and a porous granular-type Co-modified ZnGA (Co-ZnGA) was prepared. The morphology of 2D ZnGA is a prerequisite for the activation by H3Co(CN)6. The catalytic properties of Co-ZnGA were evaluated by copolymerization of various epoxides and CO2, and exhibited catalytic activity of 855, 1540, 1190, and 148 g g-cat−1 with propylene oxide, 1,2-epoxyhexane, 1,2-epoxybutane, and styrene oxide, respectively. This study provided a new strategy using 2D ZnGA instead of conventional ZnGA for increasing the catalytic activity in CO2 polymerization.
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- 작성일2023-01-16
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Recent defect passivation drifts and role of additive engineering in perovskite photovoltaics by Ali Hassan;Zhijie Wang, Yeong Hwan Ahn;Muhammad Azam;Abbas Ahmad Khan;Umar Farooq;Muhammad Zubair;Yu Cao Nano Energy 2022, 101(0); https://doi.org/10.1016/j.nanoen.2022.107579 Abstract Rapid progress in the efficiency of hybrid lead halide perovskite photovoltaics surpassed the semiconductor thin-film solar cells such as CdTe (cadmium telluride), CZTS (copper zinc tin sulfide), and CIGS (copper indium gallium selenide) within a decade. Furthermore, low-cost solution processibility demonstrated the immense potential of perovskite solar cells (PSCs) as an alternative to commercially available light-harvesting materials. Despite the fast-track development in perovskite photovoltaic technology, several drawbacks are mainly linked with defects, including undercoordinated ions, band offsets, grain boundaries, photocurrent hysteresis, and environmental instability: restraint the industrialization of perovskite photovoltaics. Herein, we present the comprehensive knowledge of the source, nature, correlation with photophysical properties, and overlapping effects of these defects. The defects are categorized based on their energy levels within the conduction and valence bands, such as deep or shallow level defects, and their dimensionality (e.g., point defects such as vacancies, dislocation, grain boundaries, and cracks are regarded as zero-, one-, two-, and three-dimensional defects). Furthermore, we developed the fundamental understanding of defect-mediated, nonradiative recombination, ion migration, carrier trapping, and their cross-link with device performance and photocurrent hysteresis. Besides, an overview of topical defect passivation strategies on perovskite absorber, materials interface, charge transport layers, surface passivation, contact passivation, and additive engineering has been spotlighted. Finally, based on past and present defect healing drifts, we have summarized and recommended suggestions for next-generation PSCs, which will pave the way for swift industrialization. Keywords Perovskite solar cellsEnergy harvestingAdditive engineeringDefect passivationPhotovoltaics
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[논문] 이창한 - A Method to Study α-Synuclein Toxicity and Aggregation Using a Humanized Yeast Model 위치 확인