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Seoul, South Korea

Sungkyunkwan University is a private research university with campuses in Seoul and Suwon. Originally, it was founded in 1398 by the Joseon Dynasty located in the heart of central Seoul. It was authorized as Sungkyunkwan, the foremost educational institution of Joseon, by the great code of the state administration pertaining to the royal assent.Today, the university has two campuses: the Humanities and Social science Campus in Seoul, and the Natural science Campus in Suwon. Eighteen schools and three colleges offer degrees at the bachelor's level, and twelve graduate schools confer various degrees at both the masters and doctoral levels. SKKU offers Korea’s first fully English-taught Global MBA program, which has gained tremendous international recognition. SKKU also has one of the best medical schools in South Korea, which is affiliated with the world-famous Samsung Medical Center. Samsung partnered with SKKU in the period of 1965-1977 and took up its partnership in 1996. Recent years have seen a trend of SKKU rising in university rankings, consistently placing in the top 5 nationally. Wikipedia.

Park N.-G.,Sungkyunkwan University
Materials Today | Year: 2015

Perovskite solar cells based on organometal halides represent an emerging photovoltaic technology. Perovskite solar cells stem from dye-sensitized solar cells. In a liquid-based dye-sensitized solar cell structure, the adsorption of methylammonium lead halide perovskite on a nanocrystalline TiO2 surface produces a photocurrent with a power conversion efficiency (PCE) of around 3-4%, as first discovered in 2009. The PCE was doubled after 2 years by optimizing the perovskite coating conditions. However, the liquid-based perovskite solar cell receives little attention because of its stability issues, including instant dissolution of the perovskite in a liquid electrolyte. A long-term, stable, and high efficiency (∼10%) perovskite solar cell was developed in 2012 by substituting the solid hole conductor with a liquid electrolyte. Efficiencies have quickly risen to 18% in just 2 years. Since PCE values over 20% are realistically anticipated with the use of cheap organometal halide perovskite materials, perovskite solar cells are a promising photovoltaic technology. In this review, the opto-electronic properties of perovskite materials and recent progresses in perovskite solar cells are described. In addition, comments on the issues to current and future challenges are mentioned. © 2014 Elsevier Ltd. All rights reserved.

Jung S.M.,Sungkyunkwan University
Nature communications | Year: 2013

Transforming growth factor (TGF)-β, a pivotal cytokine involved in a variety of cellular functions, transmits signals through Smad-dependent canonical and Smad-independent noncanonical pathways. In contrast to the canonical TGF-β pathway, it is unknown how noncanonical TGF-β pathways are negatively regulated. Here we demonstrate that the inhibitory Smad Smad6, but not Smad7, negatively regulates TGF-β1-induced activation of the TRAF6-TAK1-p38 MAPK/JNK pathway, a noncanonical TGF-β pathway. TGF-β1-induced Smad6 abolishes K63-linked polyubiquitination of TRAF6 by recruiting the A20 deubiquitinating enzyme in AML-12 mouse liver cells and primary hepatocytes. In addition, the knockdown of Smad6 or A20 in an animal model or cell culture system maintains TAK1 and p38 MAPK/JNK phosphorylation and increases apoptosis, emphasizing the crucial role of the Smad6-A20 axis in negative regulation of the TGF-β1-TRAF6-TAK1-p38 MAPK/JNK pathway. Therefore, our findings provide insight into the molecular mechanisms underlying negative regulation of noncanonical TGF-β pathways.

BACKGROUND: It is generally stated that oral antiviral therapy in patients with chronic hepatitis B (CHB) decreases the risk of developing hepatocellular carcinoma (HCC). Although oral nucleos(t)ide analogues (NUCs) may induce a state similar to inactive stage CHB, the long-term risk for HCC in patients treated with NUCs compared with inactive CHB is unclear.METHODS: A total of 1378 patients who were treatment naïve and started NUC therapy and 1014 patients with inactive stage CHB who were HBeAg-negative and continuously had hepatitis B DNA <2000 IU/mL during follow-up were enrolled. The NUC group was divided into two groups by continuous viral suppression: NUC complete responder (CR) group and NUC incomplete responder (IR) group. Cumulative HCC incidence rates were compared between the groups.RESULTS: The risk of developing HCC was significantly higher in the NUC CR group compared with the inactive CHB group, regardless of the presence of baseline liver cirrhosis (p<0.001). Risk factors associated with the development of HCC were treatment groups (p<0.001), age (p<0.001), sex (p<0.001) and the presence of liver cirrhosis at baseline (p=0.005). Of the NUC group, the cumulative incidence of HCC in the NUC IR group was significantly higher compared with the NUC CR group (p=0.028).CONCLUSIONS: The use of potent oral antiviral therapy can effectively suppress HBV replication in patients with CHB. However, the risk of HCC development in patients treated with oral antiviral agent is still significantly higher than patients with inactive stage CHB. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Kim M.H.,Sungkyunkwan University
Investigative ophthalmology & visual science | Year: 2013

To estimate the heritabilities of myopia and ocular biometrics among different family types among a Korean population. We studied 1508 adults in the Healthy Twin Study. Spherical equivalent, axial length, anterior chamber depth, and corneal astigmatism were measured by refraction, corneal topography, and A-scan ultrasonography. To see the degree of resemblance among different types of family relationships, intraclass correlation coefficients (ICC) were calculated. Variance-component methods were applied to estimate the genetic contributions to eye phenotypes as heritability based on the maximum likelihood estimation. Narrow sense heritability was calculated as the proportion of the total phenotypic variance explained by additive genetic effects, and linear and nonlinear effects of age, sex, and interactions between age and sex were adjusted. A total of 240 monozygotic twin pairs, 45 dizygotic twin pairs, and 938 singleton adult family members who were first-degree relatives of twins in 345 families were included in the study. ICCs for spherical equivalent from monozygotic twins, pooled first-degree pairs, and spouse pairs were 0.83, 0.34, and 0.20, respectively. The ICCs of other ocular biometrics were also significantly higher in monozygotic twins compared with other relative pairs, with greater consistency and conformity. The estimated narrow sense heritability (95% confidence interval) was 0.78 (0.71-0.84) for spherical equivalent; 0.86 (0.82-0.90) for axial length; 0.83 (0.76-0.91) for anterior chamber depth; and 0.70 (0.63-0.77) for corneal astigmatism. The estimated heritability of spherical equivalent and ocular biometrics in the Korean population suggests the compelling evidence that all traits are highly heritable.

Park N.-G.,Sungkyunkwan University
Journal of Physical Chemistry Letters | Year: 2013

Recently, perovskite CH3NH3PbI3 sensitizer has attracted great attention due to its superb light-harvesting characteristics. Organometallic or organic materials were mostly used as sensitizers for solid-state dye-sensitized solar cells at early stages. Inorganic nanocrystals have lately received attention as light harvesters due to their high light-absorbing properties. Metal chalcogenides have been investigated with solid-state dye-sensitized solar cells; however, the best power conversion efficiency was reported to be around 6%. CH3NH 3PbX3 (X = Cl, Br, or I) perovskite sensitizer made a breakthrough in solid-state mescoscopic solar cells, where the first record efficiency of around 10% was reported in 2012 using submicrometer-thick TiO 2 film sensitized with CH3NH3PbI3. A rapid increase in efficiency approaching 14% followed shortly. In this Perspective, recent progress in perovskite-sensitized solid-state mesoscopic solar cells is reviewed. On the basis of the recent achievements, a power conversion efficiency as high as 20% is expected based on optimized perovskite-based solid-state solar cells. © 2013 American Chemical Society.

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