Sung-Youl Cho

Sunlight-induced self-healing of a microcapsule-type protective coating.

Photopolymerization behavior of a methacryloxypropyl-terminated polydimethylsiloxane (MAT-PDMS) healing agent was investigated in the presence of benzoin isobutyl ether (BIE) photoinitiator by Fourier transform infrared (FT-IR) spectroscopy. MAT-PDMS and BIE were microencapsulated with urea-formaldehyde polymer. The surface and shell morphology of the microcapsules was investigated by scanning electron microscopy (SEM). Mean diameter and size distribution of the microcapsules could be controlled by agitation rate. A coating matrix formulation was prepared by sol-gel reaction of tetraethyl orthosilicate (TEOS) in the presence of a polysiloxane and by subsequent addition of an adhesion promoter. The formulation and microcapsules were mixed to give a self-healing coating formulation, which was then sprayed to surface of cellulose-fiber-reinforced-cement (CRC) board or mortar. Contact angle measurements showed that both the polymerized MAT-PDMS and the prepared coating matrix are hydrophobic, and the coating matrix has good wettability with MAT-PDMS. It was confirmed by optical microscopy and SEM that, when the self-healing coating is damaged, the healing agent is released from ruptured microcapsules and fills the damaged region. The self-healing coating was evaluated as protective coating for mortar, and it was demonstrated by water permeability and chloride ion penetration tests that our system has sunlight-induced self-healing capability. Our self-healing coating is the first example of capsule-type photoinduced self-healing system, and offers the advantages of catalyst-free, environmentally friendly, inexpensive, practical healing.

Non-ablative 1550-nm erbium-glass and ablative 10 600-nm carbon dioxide fractional lasers for acne scars: a randomized split-face study with blinded response evaluation

Background  Non‐ablative 1550‐nm erbium‐doped fractional photothermolysis systems (FPS) and 10 600‐nm carbon dioxide fractional laser systems (CO2 FS) have been effectively used to treat scars.

Fluorescence sensing of microcracks based on cycloreversion of a dimeric anthracene moiety

Novel fluorescent crack sensors have been developed based on dimeric anthracene moiety-containing polymers. Two anthracene derivatives, 9-anthraldehyde (AA) and 9-anthracenecarboxylic acid (AC), were photodimerized to obtain cyclooctane-type dimers. Crack-sensing polymers (Poly-AA and Poly-AC) were prepared by crosslinking of poly(vinyl alcohol) by using the dimers as crosslinkers. The polymers afforded transparent, hard coatings. Upon cracking, the polymers exhibited strong optical absorption and fluorescence emission while the uncracked original polymers did not. This was explained by regeneration of the anthracene moiety by mechanochemical cycloreversion of the cyclooctane dimer structure. It was found that the crack planes emitted fluorescence having emission maxima in the range of 500–600 nm when excited with 330–385 nm UV light. Absolute fluorescence quantum yield measurements indicated that the polymers could have good capability of fluorescence crack sensing. Preliminary evaluation of the crack-sensing ability of Poly-AA and Poly-AC was performed with the polymer films, and fluorescence emission was clearly observed along the crack planes upon excitation with 330–385 nm UV light. Poly-AA and Poly-AC are promising as fluorescent crack sensors because the anthracene moiety regenerated upon cracking has relatively long excitation and emission wavelengths as well as strong fluorescence.

The treatment of burn scar–induced contracture with the pinhole method and collagen induction therapy: a case report

Editor We would like to report a case of burn scar treated by a combination of the pinhole method using a carbon dioxide laser and collagen induction therapy (CIT) using a micro-needle therapy system (Dermaroller®, Horst Liebel, Germany). A 50-year-old Korean woman presented with a burn scar on the right side of her lower chin. The burn scar was made at the age of 1 year, and it pulled down the right side of the patient’s lower lip (figs 1a and 2a). She had no specific medical diseases and no treatment history for the scar except for the emergency treatment immediately after the burn injury. The irregularly surfaced burn scar extended from her right earlobe to her chin and was approximately 3 cm × 15 cm in size. After local anaesthesia with 1% lidocaine, multiple pinholes were made at intervals of 5 mm using a carbon dioxide laser. Soon after, a Dermaroller® was rolled thrice over the entire surface of the burn scar with appropriate overlap. After five sessions of a combined treatment of the pinhole method and CIT at 4-week intervals, the lesion showed a relaxation of the contracture and an

Efficacy and safety of 1064‐nm Q‐switched Nd:YAG laser with low fluence for keloids and hypertrophic scars

Background  Several treatment modalities using laser devices have been used for the treatment of keloids and hypertrophic scars with various therapeutic outcomes.

Vitiligo in children and adolescents: association with thyroid dysfunction

Background  The clinical characteristics of vitiligo in children and adolescents with an emphasis on thyroid dysfunction have only been reported in a few studies.

Immunochemical and biological analysis of allergenicity with excretory-secretory products of Anisakis simplex third stage larva

Background:Anisakis simplex third stage larvae (L3) are parasites that frequently give rise to allergic responses. The larvae molt into fourth stage larvae (L4), and at each stage they produce L3-excretory-secretory products (L3-ESP) and L4-ESP, respectively, which are different in their main protein constituents. Although the allergenicity of L4-ESP has been investigated by several research groups, research on the allergenicity of L3-ESP has not been carried out by any researcher. In this investigation, the allergenicity and antigenicity of L3-ESP were investigated in comparison with L4-ESP, using rat sera. Methods: Rat sera were produced by L3 oral infection two times with a 9-week interval. Larvae ESP prepared by culture were concentrated and fractioned using lyophilizer and a centrifugal filter device, respectively. Immunochemical analysis was performed using both indirect ELISA and immunoblot. Biological allergenicity was analyzed by RBL-2H3 exocytosis. Results: With the indirect ELISA, the optical density (OD) value of the nonfractioned (NF)-L3ESP was only one third of that of the NF-L4ESP in both specific IgM and IgG. On measuring specific IgE, the OD of NF-L3ESP was less than one tenth of that of NF-L4ESP. In addition, neither antigen nor allergen was shown in NF-L3ESP, but it was shown in NF-L4ESP with immunoblot. However, the biological allergenicity of NF-L3ESP was comparable to that of NF-L4ESP. To demonstrate the presence of any allergen, L3-ESP was fractioned and found to carry twelve visualized allergen bands from 10 to 186 kDa by immunoblot. Conclusions: These results indicate that L3-ESP may include the important allergens necessary to induce the allergy by L3 oral infection, as compared to L4-ESP.

Changing clinical expression of Behçet disease in Korea during three decades (1983–2012): chronological analysis of 3674 hospital‐based patients

Behçet disease (BD) is a chronic multisystemic vasculitis affecting blood vessels of any calibre or type. Recent evidence suggests that the clinical expression of BD is lessening.

Enhancing effect of pretreatment with topical niacin in the treatment of rosacea‐associated erythema by 585‐nm pulsed dye laser in Koreans: a randomized, prospective, split‐face trial

Background  Rosacea is a chronic dermatosis that is usually confined to the face. A pulsed dye laser (PDL) system has been proven to be effective in treating rosacea‐associated erythema and telangiectasias. Niacin is a cutaneous vasodilator that can increase the chromophore through increased blood flow.

Preparation and characterization of nanoporous polyimide films from triblock copolyimides

Nanoporous polyimide films were prepared from triblock copolyimides. A thermally labile polymer, poly(propylene glycol), was incorporated into polyimides based on 4,4-(hexafluoroisopropylidene)diphthalic anhydride to obtain triblock copolyimides. Nanofoams were formed by thermolysis of the labile block. The thermal properties of the copolymers were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The nanopores were characterized by scanning electron microscopy (SEM).