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578 results on '"Yoon, Dae Sung"'

22. High-Porosity Sieve-Type Neural Electrodes for Motor Function Recovery and Nerve Signal Acquisition.

Author

Choi, Wonsuk, Park, HyungDal, Oh, Seonghwan, Seok, Seonho, Yoon, Dae Sung, and Kim, Jinseok

Subjects
ELECTRODE performance, ELECTRIC impedance, BRAIN-computer interfaces, SCIATIC nerve, IMMUNOHISTOCHEMISTRY, NERVOUS system regeneration
Abstract

In this study, the effects of electrode porosity on nerve regeneration and functional recovery after sciatic nerve transection in rats was investigated. A sieve-type neural electrode with 70% porosity was designed and compared with an electrode with 30% porosity. Electrodes were fabricated from photosensitive polyimide and implanted into the transected sciatic nerves. Motor function recovery was evaluated using the Sciatic Function Index. The number of active channels and their signal quality were recorded and analyzed to assess the sensory neural signal acquisition. Electrical impedance spectroscopy was used to evaluate the electrode performance. The group implanted with the 70% porosity electrode demonstrated significantly enhanced nerve regeneration and motor function recovery, approaching control group levels by the fifth week. In contrast, the group with the 30% porosity electrode exhibited limited improvement. Immunohistochemical analysis confirmed extensive nerve fiber growth within the 70% porous structure. Moreover, the 70% porosity electrode consistently acquired neural signals from more channels compared to the 30% porosity electrode, demonstrating its superior performance in sensory signal detection. These findings emphasize the importance of optimizing electrode porosity in the development of advanced neural interfaces, with the potential to enhance clinical outcomes in peripheral nerve repair and neuroprosthetic applications. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Single-incision versus conventional multiport laparoscopic cholecystectomy in acute cholecystitis according to disease severity: single center retrospective study in Korea

Author

Lee, Seung Jae, primary, Moon, Ju Ik, additional, Lee, Sang Eok, additional, Sung, Nak Song, additional, Kwon, Seong Uk, additional, Bae, In Eui, additional, Rho, Seung Jae, additional, Kim, Sung Gon, additional, Kim, Min Kyu, additional, Yoon, Dae Sung, additional, Choi, Won Jun, additional, and Choi, In Seok, additional

Published
2023
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31. Nanomechanical Resonators and Their Applications in Biological/Chemical Detection: Nanomechanics Principles

Author

Eom, Kilho, Park, Harold S., Yoon, Dae Sung, and Kwon, Taeyun

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Recent advances in nanotechnology have led to the development of nano-electro-mechanical systems (NEMS) such as nanomechanical resonators, which have recently received significant attention from the scientific community. This has not only been for their capability for the label-free detection of bio/chemical-molecules at single-molecule (or atomic) resolution for future applications such as the early diagnostics of diseases such as cancer, but also for their unprecedented ability to detect physical quantities such as molecular weight, elastic stiffness, surface stress, and surface elastic stiffness for adsorbed molecules on the surface. Most experimental works on resonator-based molecular detection have been based on the principle that molecular adsorption onto a resonator surface increases the effective mass, and consequently decreases the resonant frequencies of the nanomechanical resonator. However, this principle is insufficient to provide fundamental insights into resonator-based molecular detection at the nanoscale; this is due to recently proposed novel nanoscale detection principles including various effects such as surface effects, nonlinear oscillations, coupled resonance, and stiffness effects. Therefore, our objective in this review is to overview the current attempts to understand the underlying mechanisms in nanoresonator-based detection using physical models coupled to computational simulations and/or experiments. Specifically, we will focus on issues of special relevance to the dynamic behavior of nanoresonators and their applications in biological/chemical detection. We additionally provide extensive discussion regarding potentially fruitful future research directions coupling experiments and simulations in order to develop a fundamental understanding of the basic physical principles that govern NEMS and NEMS-based sensing applications.

Published
2011
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33. Dynamical Response of Nanomechanical Resonators to Biomolecular Interactions

Author

Eom, Kilho, Kwon, Tae Yun, Yoon, Dae Sung, Lee, Hong Lim, and Kim, Tae Song

Subjects
Condensed Matter - Soft Condensed Matter, Quantitative Biology - Quantitative Methods
Abstract

We studied the dynamical response of a nanomechanical resonator to biomolecular (e.g. DNA) adsorptions on a resonator's surface by using a theoretical model, which considers the Hamiltonian H such that the potential energy consists of elastic bending energy of a resonator and the potential energy for biomolecular interactions. It was shown that the resonant frequency shift of a resonator due to biomolecular adsorption depends on not only the mass of adsorbed biomolecules but also the biomolecular interactions. Specifically, for dsDNA adsorption on a resonator's surface, the resonant frequency shift is also dependent on the ionic strength of a solvent, implying the role of molecular interactions on the dynamic behavior of a resonator. This indicates that nanomechanical resonators may enable one to quantify the biomolecular mass, implying the enumeration of biomolecules, as well as gain insight into intermolecular interactions between adsorbed biomolecules on the surface., Comment: 17 page, 4 figures, accepted for publication at PRB. Physical Review B, accepted

Published
2007
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41. Biomimetically Engineered Amyloid-Shelled Gold Nanocomplexes for Discovering α-Synuclein Oligomer-Degrading Drugs

Author

Lee, Dongtak, primary, Jung, Hyo Gi, additional, Park, Dongsung, additional, Bang, Junho, additional, Hong, Ji Hye, additional, Lee, Sang Won, additional, Roh, Seokbeom, additional, Jang, Jae Won, additional, Kim, Yonghwan, additional, Hwang, Kyo Seon, additional, Lee, Young-Sun, additional, Park, Jae-Yong, additional, Jung, In Duk, additional, Lee, Jeong Hoon, additional, Lee, Gyudo, additional, and Yoon, Dae Sung, additional

Published
2022
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46. Interface‐Controlled Biomimetic Intrafibrillar Mineralization of Collagen: Effect of Ca2+/[PO4]3− Concentration Ratio.

Author

Amornkitbamrung, Urasawadee, In, Yongjae, Lee, Jung Heon, Wang, Zhen, Oh, Sang Ho, Shin, Heungsoo, Yoon, Dae Sung, and Shin, Hyunjung

Subjects
MINERALIZATION, COLLAGEN, PHASE transitions, CALCIUM phosphate, BODY fluids, CRYSTALLIZATION kinetics, HYDROXYAPATITE
Abstract

Mineralized fibrils are important building blocks in bone tissue, formed by the hierarchical assembly of collagen molecules and crystalline hydroxyapatite (HAp). The mineralization pathway of HAp is reported as a nonclassical‐crystallization, but the nanoconfined crystallization in collagen fibrils remains poorly understood. The mechanism of intrafibrillar mineralization of collagen‐PDA fibrils in modified‐simulated body fluid (m‐SBF) solution is studied. Collagen‐amorphous calcium phosphate (ACP) fibrils are obtained by assembling collagen‐PDA fibrils with polyaspartic acid (pAsp) as a stabilizer. The ACP undergoes a phase transformation to HAp within the fibrils upon adjusting the phosphate concentration. It is found that the phase transformation of ACP to HAp in collagen fibrils can be accelerated with a 12 h incubation with 1/10 ratio of Ca2+ to [PO4]3−. A lower ratio of 1/1 and 1/5 results in a much slower phase transformation. This finding suggests that an elevated concentration of [PO4]3− is crucial for faster phase transformation. The relationship between the crystallization rate of HAp in the fibrils and the degree of mineralization is found to be linear in all cases, indicating an interface‐controlled process. This gives a better understanding of the mechanism of HAp mineralization in collagen fibrils, providing an effective approach to material design. [ABSTRACT FROM AUTHOR]

Published
2023
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49. Melanoma Detection by AFM Indentation of Histological Specimens

Author

Jeon, Byoungjun, primary, Jung, Hyo Gi, additional, Lee, Sang Won, additional, Lee, Gyudo, additional, Shim, Jung Hee, additional, Kim, Mi Ok, additional, Kim, Byung Jun, additional, Kim, Sang-Hyon, additional, Lee, Hyungbeen, additional, Lee, Sang Woo, additional, Yoon, Dae Sung, additional, Jo, Seong Jin, additional, Choi, Tae Hyun, additional, and Lee, Wonseok, additional

Published
2022
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