Anti-reflective nano- and micro-structures on 4H-SiC for photodiodes

In this study, nano-scale honeycomb-shaped structures with anti-reflection properties were successfully formed on SiC. The surface of 4H-SiC wafer after a conventional photolithography process was etched by inductively coupled plasma. We demonstrate that the reflection characteristic of the fabricated photodiodes has significantly reduced by 55% compared with the reference devices. As a result, the optical response Iillumination/Idark of the 4H-SiC photodiodes were enhanced up to 178%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing

High-quality thin-film passivation by catalyzer-enhanced chemical vapor deposition for organic light-emitting diodes

The thin-film passivation of organic light-emitting diodes (OLEDs) by a SiNx film grown by catalyzer-enhanced chemical vapor deposition was investigated. Using a tungsten catalyzer connected in series, a high-density SiNx passivation layer was deposited on OLEDs and bare polycarbonate (PC) substrates at a substrate temperature of 50 °C. Despite the low substrate temperature, the single SiNx passivation layer, grown on the PC substrate, exhibited a low water vapor transmission rate of (2–6)×10−2 g/m2/day and a high transmittance of 87%. In addition, current-voltage-luminescence results of an OLED passivated with a 150-nm-thick SiNx film compared to nonpassivated sample were identical indicating that the performance of an OLED is not critically affected by radiation from tungsten catalyzer during the SiNx deposition. Moreover, the lifetime to half initial luminance of an OLED passivated with the single 150-nm-thick SiNx layer was 2.5 times longer than that of a nonpassivated sample.This work was supported by Korea Research Foundation Grant funded by Korea Government (MOEHRD: Basic Research Promotion Fund)(KRF-2006-331-D00243) and Ministry of Commerce, Industry and Energy. Experiments at PLS were supported in part by MOST and POSTECH

Enhancement of hole injection using ozone treated Ag nanodots dispersed on indium tin oxide anode for organic light emitting diodes

The authors report the enhancement of hole injection using an indium tin oxide (ITO) anode covered with ultraviolet (UV) ozone-treated Ag nanodots for fac tris (2-phenylpyridine) iridium Ir(ppy)3-doped phosphorescent organic light-emitting diodes (OLEDs). X-ray photoelectron spectroscopy and UV-visible spectrometer analysis exhibit that UV-ozone treatment of the Ag nanodots dispersed on the ITO anode leads to formation of Ag2O nanodots with high work function and high transparency. Phosphorescent OLEDs fabricated on the Ag2O nanodot-dispersed ITO anode showed a lower turn-on voltage and higher luminescence than those of OLEDs prepared with a commercial ITO anode. It was thought that, as Ag nanodots changed to Ag2O nanodots by UV-ozone treatment, the decrease of the energy barrier height led to the enhancement of hole injection in the phosphorescent OLEDs.This work was supported by Korea Research Foundation grant funded by Korean Government (MOEHRD: Basic Research Promotion Fund)(KRF-2006-003-D00243) and Ministry of Commerce, Industry, and Energy

Tat peptide-admixed elastic liposomal formulation of hirsutenone for the treatment of atopic dermatitis in NC/Nga mice

Myung Joo Kang1, Jae Yoon Eum1, Mi Sook Jeong2, Sang Han Park1, Ki Young Moon1, Mean Hyung Kang1, Min Soo Kim1, Sun Eun Choi1, Min Won Lee1, Do Ik Lee1, Hyoweon Bang2, Chung Soo Lee2, Seong Soo Joo3, Kapsok Li2, Mi-Kyung Lee2, Seong Jun Seo2, Young Wook Choi11College of Pharmacy, ChungAng University, Heuksuk-dong, Dongjak-gu, Seoul, 2College of Medicine, Chung-Ang University, Heuksukdong, Dongjak-gu, Seoul, 3Division of Marine Molecular Biotechnology, Gangneung-Wonju National University, Gangneung, South KoreaBackground: The aim of the present study was to enhance a topical delivery of hirsutenone (HST), a naturally occuring immunomodulator, employing Tat peptide-admixed elastic liposomes (EL/T).Methods: HST-loaded EL, consisting of phosphatidylcholine and Tween 80 (85:15 w/w%), were prepared using thin film hydration method. By adding Tat peptide to EL (0.16 w/w%), EL/T were formulated. The in vitro skin permeation of HST was examined using a Franz diffusion cell mounted with depilated mouse skin. Lesions for atopic dermatitis (AD) were induced by a topical application of diphenylcyclopropenone to NC/Nga mice. Therapeutic improvements of AD were evaluated by clinical skin severity scores. Immunological analyses on inducible nitric oxide synthase and cyclooxygenase-2 levels in the skin and interleukin (IL)-4, IL-13, immunoglobulin E, and eosinophil levels in the blood were also performed.Results: EL systems were superior to conventional cream, revealing greater flux values in a permeation study. The addition of Tat peptide further increased the skin permeation of HST. In an efficacy study with AD-induced NC/Nga mice, an HST-containing EL/T formulation brought a significant improvement in both skin severity score and immune-related responses for the levels of nitric oxide synthase, cyclooxygenase-2, IL-4, IL-13, immunoglobulin E, and eosinophils.Conclusion: A novel EL/T formulation was successfully developed for topical delivery of HST to treat AD.Keywords: hirsutenone, elastic liposomes, atopic dermatitis, NC/Nga mice, Tat peptid

Adenocarcinoma Arising in a Duplication of the Cecum

Intestinal duplications are rare developmental abnormalities that may occur anywhere in the gastrointestinal tract. The possibility of a malignant change occurring in these duplications is very low. We present a case of adenocarcinoma arising in a duplication of the cecum. A 41-year-old male patient was admitted because of a palpable abdominal mass. Abdominal computed tomography revealed a 6-cm, peripheral wall-enhanced, round, cystic mass in the cecal area. Excision of the mesenteric mass and a right hemicolectomy was performed. Upon histologic examination, the patient was diagnosed with adenocarcinoma arising in a duplication of the cecum