연구성과 게시판목록 | 기초과학 자율운영 중점연구소

Total 177건, 17/18

17
[논문] 유영동 - Enhanced Optical Third-Harmonic Generation in Phase-Engineered MoTe2 Thin Films 위치 확인

Enhanced Optical Third-Harmonic Generation in Phase-Engineered MoTe2 Thin Films by Seongju Ha;Hyeonkyeong Kim;Hyunjun Nam;Jungseok Choi;Kwanbyung Chae;Jae-Ung Lee;Ji-Yong Park;Youngdong Yoo;Dong-Il Yeom ACS Photonics, 2022 https://doi.org/10.1021/acsphotonics.2c00222 Abstract Molybdenum ditelluride (MoTe2) is a relatively unexplored layered transition metal dichalcogenide in nonlinear optics. Several recent studies have shown that MoTe2 has strong second-order optical nonlinearities originating from tellurium atoms. However, the third-order optical nonlinearities of MoTe2 have not been explored yet, except for the nonparametric saturable absorption process. Here we report the enhanced optical third-harmonic generation in phase-engineered MoTe2 thin films. MoTe2 films, including 2H and 1T′ phases simultaneously, are synthesized by the flux-controlled phase-engineering method, and their nonlinear response is characterized. We observe that the 2H-MoTe2 film exhibits up to a 15-fold stronger nonlinear signal than that of the 1T′-phase film. The estimated third-order effective nonlinear susceptibility of 2H-MoTe2 is 9.3 × 10–19 m2 V–2 maximum, which is larger than highly nonlinear layered materials such as molybdenum disulfide. Our MoTe2 film synthesized with the desired phase over a large area will be a potential building block for ultrathin nonlinear photonics.
- 16
- 작성자박은영
- 작성일2023-01-13
- 595
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
15
[논문] 안영환 - Terahertz thermal curve analysis for label-free identification of pathogens 위치 확인

Terahertz thermal curve analysis for label-free identification of pathogens by S. W. Jun;Y. H. Ahn Nature Communications, 2022 https://doi.org/10.1038/s41467-022-31137-2 Abstract In this study, we perform a thermal curve analysis with terahertz (THz) metamaterials to develop a label-free identification tool for pathogens such as bacteria and yeasts. The resonant frequency of the metasensor coated with a bacterial layer changes as a function of temperature; this provides a unique fingerprint specific to the individual microbial species without the use of fluorescent dyes and antibodies. Differential thermal curves obtained from the temperature-dependent resonance exhibit the peaks consistent with bacterial phases, such as growth, thermal inactivation, DNA denaturation, and cell wall destruction. In addition, we can distinguish gram-negative bacteria from gram-positive bacteria which show strong peaks in the temperature range of cell wall destruction. Finally, we perform THz melting curve analysis on the mixture of bacterial species in which the pathogenic bacteria are successfully distinguished from each other, which is essential for practical clinical and environmental applications such as in blood culture.
- 14
- 작성자박은영
- 작성일2023-01-13
- 586
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
13
[논문] 김유권 - WS2/p-Si-based photocathodes with high activity originated from the unique vertical geometry of the 2D WS2 위치 확인

WS2/p-Si-based photocathodes with high activity originated from the unique vertical geometry of the 2D WS2 nanoplatelets by Malkeshkumar Patel;Thanh Tai Nguyen;Jina Kim;Joondong Kim;Yu Kwon Kim FlatChem, 2022 https://doi.org/10.1016/j.flatc.2022.100361 Abstract Earth-abundant two-dimensional (2D) materials-based photocathodes for solar hydrogen production may replace conventional noble metal-based ones when they can be grown with a proper orientation and dimension for efficient charge transfer and catalytic reactions. Here, we show that WS2 films can be grown as wafer-scale films with unique vertically aligned 2H-WS2 nanoplatelets using a single-step vacuum deposition process directly on substrates such as Si wafer and F-doped tin oxide (FTO)/glass. The as-grown WS2/p-Si shows enhanced photocathode performances that are attributed to the unique vertical WS2 nanoplatelet structure, which endows excellent antireflection properties (reflectance as low as ∼ 4%) for enhanced absorption, high photocurrent density (ca. 37 mA cm−2) at low overpotential optimized by controlled vertical length, and catalytically active WS2 edge-sites exposed to the surface for excellent catalytic hydrogen evolution reaction (HER). The results suggest that the nanostructured WS2/p-Si heterostructures are promising multi-functional photocathodes for solar hydrogen production with excellent stability for long-term operation in ambient condition.
- 12
- 작성자박은영
- 작성일2023-01-13
- 615
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
11
[논문] 안수현 - Percutaneous radiofrequency ablation of hepatocellular carcinoma in a recent cohort of a tertiary cancer cent 위치 확인

Percutaneous radiofrequency ablation of hepatocellular carcinoma in a recent cohort of a tertiary cancer center: Incidence and factors associated with major complications and unexpected hospitalization events by Min Geun Jo;Min Woo Lee;Soohyun Ahn;Tae Wook Kang;Kyoung Doo Song;Dong Ik Cha;Ji Hye Min;Hyunchul Rhim ultrasonography, 2022 https://doi.org/10.14366/usg.22041 Abstract Purpose This study aimed to assess the incidence of and factors associated with major complications, delayed discharge, and emergency room (ER) visits or readmission after percutaneous radiofrequency ablation (RFA) for single hepatocellular carcinoma (HCC) Methods A total of 188 patients with treatment-naïve single HCCs Results Major complications occurred in 3.2% (6/188) of the patients. The longest diameter of the ablation zone was significantly larger in patients with major complications (P=0.023). Delayed discharge occurred in 5.8% (9/188) of the patients, for which albumin-bilirubin grade 3 was identified as an important determinant. No variables other than major complications were significantly associated with ER visits or readmission, which occurred in 7.0% (13/188) of the patients. Major complications, delayed discharge, and ER visits or readmission were not substantially related to the post-treatment outcomes of LTP and overall survival. Conclusion This study confirmed RFA as a highly safe procedure for single HCCs Keywords: Hepatocellular carcinoma; Radiofrequency ablation; Complications
- 10
- 작성자박은영
- 작성일2023-01-13
- 630
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
9
[논문] 장혜영 - Sustainable Catalytic Synthesis of 2,5-Diformylfuran from Various Carbohydrates 위치 확인

Sustainable Catalytic Synthesis of 2,5-Diformylfuran from Various Carbohydrates by Si Ae Kim;Kihyuk Sung;June Young Jang;Sohee Bang;Seung Uk Son;Hye-Young Jang Catalysts, 2022 https://doi.org/10.3390/catal12040360 Abstract Versatile homogeneous and heterogeneous catalysts that convert carbohydrates to 2,5-diformylfuran (DFF) are essential for the development of sustainable processes for producing high-value chemicals from biomass-derived carbohydrates. An efficient catalytic system consisting of Br−, disulfide, and dimethylsulfoxide (DMSO) promoted the sustainable and selective synthesis of DFF in modest-to-good yields from various carbohydrates, such as fructose, glucose, mannose, galactose, and sucrose. Heterogeneous catalysts containing Br− also facilitated this reaction with recyclable high yields. Keywords: biomass; carbohydrates; 2,5-diformylfuran; fructose; glucose
- 8
- 작성자박은영
- 작성일2023-01-13
- 578
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
7
[논문] 이효원 - Highly Sensitive Two-Photon Lipid Droplet Tracker for In Vivo Screening of Drug Induced Liver Injury 위치 확인

Highly Sensitive Two-Photon Lipid Droplet Tracker for In Vivo Screening of Drug Induced Liver Injury by Hyo Won Lee;In-Jeong Lee;Soo-Jin Lee;Yu Rim Kim;Hwan Myung Kim ACS Sensors, 2022 https://doi.org/10.1021/acssensors.1c02679 Abstract Lipid droplets (LDs) are lipid-abundant organelles found in most cell lines and primarily consist of neutral lipids. They serve as a repository of various lipids and are associated with many cellular metabolic processes, including energy storage, membrane synthesis, and protein homeostasis. LDs are prominent in a variety of diseases related to lipid regulation, including obesity, fatty liver disease, diabetes, and atherosclerosis. To monitor LD dynamics in live samples, we developed a highly selective two-photon fluorescent tracker for LDs (LD1). It exhibited outstanding sensitivity with a remarkable two-photon-action cross section (Φδmax > 600 GM), photostability, and low cytotoxicity. In human hepatocytes and in vivo mouse liver tissue imaging, LD1 showed very bright fluorescence with high LD selectivity and minimized background signal to evaluate the stages of nonalcoholic fatty liver disease. Interestingly, we demonstrated that the liver sinusoid morphology became narrower with increasing LD size and visualized the dynamics including fusion of the LDs in vivo. Moreover, real-time and dual-color TPM imaging with LD1 and a two-photon lysosome tracker could be a useful predictive screening tool in the drug development process to monitor impending drug-induced liver injury inducing drug candidates. KEYWORDS: lipid droplets fatty liver disease steatosis phospholipidosis in vivo imaging
- 6
- 작성자박은영
- 작성일2023-01-13
- 624
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
5
[논문] 박대찬 - ESubstrate-binding loop interactions with pseudouridine trigger conformational changes that promote catalytic 위치 확인

Substrate-binding loop interactions with pseudouridine trigger conformational changes that promote catalytic efficiency of pseudouridine kinase PUKI by Sang-HoonKim;Minjeong Kim;Daechan Park;Sujeong Byun;Sangkee Rhee Journal of Biological Chemistry, 2022 https://doi.org/10.1016/j.jbc.2022.101869 Abstract Pseudouridine, one major RNA modification, is catabolized into uracil and ribose-5′-phosphate by two sequential enzymatic reactions. In the first step, pseudouridine kinase (PUKI) phosphorylates pseudouridine to pseudouridine 5′-monophosphate. High-fidelity catalysis of pseudouridine by PUKI prevents possible disturbance of in vivo pyrimidine homeostasis. However, the molecular basis of how PUKI selectively phosphorylates pseudouridine over uridine with >100-fold greater efficiency despite minor differences in their Km values has not been elucidated. To investigate this selectivity, in this study we determined the structures of PUKI from Escherichia coli strain B (EcPUKI) in various ligation states. The structure of EcPUKI was determined to be similar to PUKI from Arabidopsis thaliana, including an α/β core domain and β-stranded small domain, with dimerization occurring via the β-stranded small domain. In a binary complex, we show that Ser30 in the substrate-binding loop of the small domain mediates interactions with the hallmark N1 atom of pseudouridine nucleobase, causing conformational changes in its quaternary structure. Kinetic and fluorescence spectroscopic analyses also showed that the Ser30-mediated interaction is a prerequisite for conformational changes and subsequent catalysis by EcPUKI. Furthermore, S30A mutation or EcPUKI complexed with other nucleosides homologous to pseudouridine but lacking the pseudouridine-specific N1 atom did not induce such conformational changes, demonstrating the catalytic significance of the proposed Ser30-mediated interaction. These analyses provide structural and functional evidence for a pseudouridine-dependent conformational change of EcPUKI and its functional linkage to catalysis.
- 4
- 작성자박은영
- 작성일2023-01-13
- 669
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
3
[논문] 김유권, 김승주 - Effect of the Plasma Gas Type on the Surface Characteristics of 3Y-TZP Ceramic 위치 확인

Effect of the Plasma Gas Type on the Surface Characteristics of 3Y-TZP Ceramic by Sung-Un Kang;Chul-Ho Kim;Hee-Kyung Kim;Ye-Won Yoon;Yu-Kwon Kim;Seung-Joo Kim International Journal of Molecular Sciences, 2022 https://doi.org/10.3390/ijms23063007 Abstract Plasma surface treatment can be an attractive strategy for modifying the chemically inert nature of zirconia to improve its clinical performance. This study aimed to clarify the effect of plasma gas compositions on the physicochemical surface modifications of 3 mol% yttria-stabilized zirconia (3Y-TZP). The cold, atmospheric plasma discharges were carried out by using four different plasma gases, which are He/O2, N2/Ar, N2, and Ar from an application distance of 10 mm for 60 s. Static contact angles were measured to define the surface free energy. Changes in elemental composition, surface crystallinity, and surface topography were assessed with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM), respectively. A significant decrease in water contact angle was observed in all plasma groups with the lowest value of 69° in the N2/Ar group. CLSM and SEM investigations exhibited no morphological changes in all plasma groups. XPS revealed that a reduction in the surface C content along with an increase in O content was pronounced in the case of N2/Ar compared to others, which was responsible for high hydrophilicity of the surface. XRD showed that the changes in crystallite size and microstrain due to oxygen atom displacements were observed in the N2/Ar group. The N2/Ar plasma treatment may contribute to enhancing the bioactivity as well as the bonding performance of 3Y-TZP by controlling the plasma-generated nitrogen functionalities. Keywords: plasma gases; zirconium oxide; surface properties; nitrogen; wettability
- 2
- 작성자박은영
- 작성일2023-01-13
- 615
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
1
[논문] 김기홍, 김슬옹 - Mode conversion and resonant absorption in inhomogeneous materials with flat bands 위치 확인

Mode conversion and resonant absorption in inhomogeneous materials with flat bands by Kihong Kim;Seulong Kim Physical Review b, 2022 https://doi.org/10.1103/PhysRevB.105.045136 Abstract Mode conversion of transverse electromagnetic waves into longitudinal oscillations and the associated resonant absorption of wave energy in inhomogeneous plasmas is a phenomenon that has been studied extensively in plasma physics. We show that precisely analogous phenomena occur generically in electronic and photonic systems where dispersionless flat bands and dispersive bands coexist in the presence of an inhomogeneous potential or medium parameter. We demonstrate that the systems described by the pseudospin-1 Dirac equation with two dispersive bands and one flat band display mode conversion and resonant absorption in a very similar manner to p-polarized electromagnetic waves in an unmagnetized plasma by calculating the mode conversion coefficient explicitly using the invariant imbedding method. We also show that a similar mode conversion process takes place in many other systems with a flat band such as pseudospin-2 Dirac systems, continuum models obtained for one-dimensional stub and sawtooth lattices, and two-dimensional electron systems with a quadratic band and a nearly flat band. We discuss some experimental implications of mode conversion in flat-band materials and metamaterials.
- 0
- 작성자박은영
- 작성일2023-01-13
- 609
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910
-1
[논문] 이창한 - ATP-Independent Chaperones 위치 확인

ATP-Independent Chaperones by Rishav Mitra;Kevin Wu;Changhan Lee;James C A Bardwell Annual Review of Biophysics, 2022 https://doi.org/10.1146/annurev-biophys-090121-082906 Abstract The folding of proteins into their native structure is crucial for the functioning of all biological processes. Molecular chaperones are guardians of the proteome that assist in protein folding and prevent the accumulation of aberrant protein conformations that can lead to proteotoxicity. ATP-independent chaperones do not require ATP to regulate their functional cycle. Although these chaperones have been traditionally regarded as passive holdases that merely prevent aggregation, recent work has shown that they can directly affect the folding energy landscape by tuning their affinity to various folding states of the client. This review focuses on emerging paradigms in the mechanism of action of ATP-independent chaperones and on the various modes of regulating client binding and release. Keywords protein folding, Spy, trigger factor, SurA, small heat shock proteins, holdase
- -2
- 작성자박은영
- 작성일2023-01-13
- 613
- 동영상동영상
E-House 301동 기숙사식당

02-3277-5910