Young-Ho Cho

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Free radicals and reactive oxygen species (ROS), which are generated by UV irradiation, may cause serious injury to skin cell membranes, DNA and functional proteins. In addition, these agents stimulate the expressions of matrix metalloproteinases (MMPs), which can degrade most components of the extracellular matrix (ECM), including collagen. In order to(More)
BACKGROUND The purpose of the current study was to investigate the incidence of preoperative deep vein thrombosis (DVT) after hip fractures in Korea. METHODS In this prospective study, we enrolled 152 Korean geriatric patients who had suffered hip fractures due to a simple fall and were hospitalized between January 2013 and December 2013. There were 52(More)
Frequency tunable comb resonators have been successfully designed and demonstrated based on a closed-form approach of a curved comb finger contour. Experimentally, the resonant frequency of a laterally driven comb resonator with 186 pairs of curved finger contour has been reduced by 55% from the initial frequency of 19 kHz under a bias voltage of 150 V. The(More)
The purpose of the present investigation was to develop and evaluate a self-microemulsifying drug delivery system (SMEDDS) for improving the oral absorption of a pranlukast hemihydrate (PLH), a very poorly water-soluble drug. An efficient self-microemulsifying vehicle for PLH was selected and optimized using solubility testing and phase diagram(More)
This paper presents a multicellular spheroid chip capable of forming and extracting three-dimensional (3D) spheroids using removable cell trapping barriers. Compared to the conventional macro-scale spheroid formation methods, including spinning, hanging-drop, and liquid-overlay methods, the recent micro-scale spheroid chips have the advantage of forming(More)
This paper presents a spheroid chip in which three-dimensional (3D) tumor spheroids are not only formed by gravity-driven cell aggregation but also cultured at the perfusion rates controlled by balanced droplet dispensing without fluidic pumps. The previous spheroid chips require additional off-chip processes of spheroid formation and extraction as well as(More)
We present passive flow-rate regulators using an autonomous deflection of parallel membrane valves, capable to maintain a constant flow-rate at varying inlet pressure supplied from micropumps. The previous passive flow-rate regulators are difficult to integrate with micropumps, not only because of the complex multi-layer structures, but also because of the(More)
We present a three-dimensional (3D) particle focusing channel using the positive dielectrophoresis (pDEP) guided by a dielectric structure between two planar electrodes. The dielectric structure between two planar electrodes induces the maximum electric field at the center of the microchannel and particles are focused to the center of the microchannel by(More)
This paper presents tapered-slit membrane filters for high-throughput viable circulating tumor cell (CTC) isolation. The membrane filter with a 2D array of vertical tapered slits with a gap that is wide at the entrance and gradually decreases with depth, provide minimal cell stress and reduce 82.14% of the stress generated in conventional straight-hole(More)
This paper presents a pumpless cell culture chip, where a constant-rate medium perfusion is achieved by balanced droplet dispensing. Previous pumpless cell culture chips, where the gravity-driven flow is induced by gradually decreasing the hydraulic-head difference, Δh, between source and drain reservoirs, result in a decreasing perfusion-rate. However, the(More)