Youjin Cheong

Learn More
This paper presents a new analysis method for aortic and mitral insufficient murmurs using wavelet packet decomposition. We proposed four diagnostic features including the maximum peak frequency, the position index of the wavelet packet coefficient corresponding to the maximum peak frequency, and the ratios of the wavelet energy and entropy information to(More)
High success rates in clinical trials on keratoconic corneas suggest the possibility of efficient treatment against myopic progression. This study quantitatively investigated the in vitro ultrastructural effects of a photooxidative collagen cross-linking treatment with photosensitizer riboflavin and UVA light in human corneo-scleral collagen fibrils. A(More)
This study examined the surface nanostructures of three orbital implants: nonporous poly(methyl methacrylate) (PMMA), porous aluminum oxide and porous polyethylene. The morphological characteristics of the orbital implants surfaces were observed by atomic force microscopy (AFM). The AFM topography, phase shift and deflection images of the intact implant(More)
The aim of this study was to quantitatively investigate the morphologies (surface roughness) and biomechanical properties (Young's modulus) of human anterior lens capsules (ALCs) for noncataract and cataract groups using atomic force microscopy. Eight human ALCs obtained during phacoemulsification from patients with senile cataracts (72 ± 13 years) were(More)
This study investigated the inflammatory effect of cryotherapy application on collagen matrix network in human infant sclera. Donor scleral tissues taken from three infant patients divided into five groups: control group, sham-treated group, and three cryotreated groups. In the cryotherapy groups, the sclera was treated for 5 s, 10 s, and 20 s with -80°C(More)
This study investigated the inflammatory effect of intraoperative mitomycin C (MMC) on adhesion reformation in human rectus muscles. Ten consecutive patients who underwent medial rectus resection had their postoperative rectus muscles divided into two groups: control group (n = 10) and MMC group (n = 10). In the MMC group, the muscle was soaked for 2 min(More)
This study quantitatively examined the short and mid-long term effects of radiofrequency (RF) treatment on the normal dermal collagen fibrils of live rabbits. Effects were evaluated by histology and scanning probe microscopy analysis of dermal tissues treated using three RF energy levels (10, 20, and 30 W) and either a single- or multiple-pass procedure.(More)
This study examined the effects of an orthodontic treatment using a bicuspid extraction on the surface roughness and mechanical properties of stainless steel (SS) brackets adjacent to the extraction space. Four experimental groups were employed; groups 1 and 2 used the Archist(®) SS brackets before and after the extraction treatment, respectively, and(More)
This study quantitatively examined the effects of monopolar radiofrequency (RF) treatment on the progressive nanostructural changes in the inflammatory effect of in vivo rabbit dermal collagen fibrils during postoperative 7 days. Conventional histologic analysis and atomic force microscopy (AFM) were employed to assess the nanostructural dermal response in(More)
This study presents a method for non-invasive screening of progressive arthritic reactions in a representative rheumatoid arthritis (RA) animal model of Type II collagen-induced arthritis (CIA). Seventeen male DBA/1J mice (9 weeks old) were used for the control group (seven) and the CIA group (ten). The CIA model was induced by the injection of a Type II(More)