Chung-Ang University

About: Chung-Ang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Thin film. The organization has 13381 authors who have published 26978 publications receiving 416735 citations. The organization is also known as: CAU & Chung.

Force-dependent hopping rates of RNA hairpins can be estimated from accurate measurement of the folding landscapes

Abstract: The sequence-dependent folding landscapes of nucleic acid hairpins reflect much of the complexity of biomolecular folding. Folding trajectories, generated by using single-molecule force-clamp experiments by attaching semiflexible polymers to the ends of hairpins, have been used to infer their folding landscapes. Using simulations and theory, we study the effect of the dynamics of the attached handles on the handle-free RNA free-energy profile Foeq(zm), where zm is the molecular extension of the hairpin. Accurate measurements of Foeq(zm) requires stiff polymers with small L/lp, where L is the contour length of the handle, and lp is the persistence length. Paradoxically, reliable estimates of the hopping rates can only be made by using flexible handles. Nevertheless, we show that the equilibrium free-energy profile Foeq(zm) at an external tension fm, the force (f) at which the folded and unfolded states are equally populated, in conjunction with Kramers' theory, can provide accurate estimates of the force-dependent hopping rates in the absence of handles at arbitrary values of f. Our theoretical framework shows that zm is a good reaction coordinate for nucleic acid hairpins under tension.

Two-dimensional transition metal dichalcogenide nanomaterials for solar water splitting

Abstract: Recently, 2-dimensional (2D) transition metal dichalcogenides (TMDs) have received great attention for solar water splitting and electrocatalysis. In addition to their wide variety of electronic and microstructural properties, their promising catalytic activities for hydrogen production make 2D TMDs as earth-abundant and inexpensive catalysts that can replace noble metals. This paper reviews the electronic, structural, and optical properties of 2D TMDs. We highlight the various synthetic methods for 2D TMDs and their applications in hydrogen evolution based on photoelectrochemical and electrocatalytic cells. We also discuss perspectives and challenges of 2D TMDs for hydrogen production and artificial photosynthesis. Open image in new window

Effects of extremely low frequency magnetic field on the antioxidant defense system in mouse brain: a chemiluminescence study.

Abstract: Among the putative mechanisms, by which extremely low frequency (ELF) magnetic field (MF) may affect biological systems is that of increasing free radical life span in organisms. To test this hypothesis, we investigated whether ELF (60 Hz) MF can modulate antioxidant system in mouse brain by detecting chemiluminescence and measuring superoxide dismutase (SOD) activity in homogenates of the organ. Compared to sham exposed control group, lucigenin-initiated chemiluminescence in exposed group was not significantly increased. However, lucigenin-amplified t-butyl hydroperoxide (TBHP)-initiated brain homogenates chemiluminescence, was significantly increased in mouse exposed to 60 Hz, MF, 12 G for 3 h compared to sham exposed group. We also measured SOD activity, that plays a critical role of the antioxidant defensive system in brain. In the group exposed to 60 Hz, MF, 12 G for 3 h, brain SOD activity was significantly increased. These results suggest that 60 Hz, MF could deteriorate antioxidant defensive system by reactive oxygen species (ROS), other than superoxide radicals. Further studies are needed to identify the kind of ROS generated by the exposure to 60 Hz, MF and elucidate how MF can affect biological system in connection with oxidative stress.

Mortality after vertebral fracture in Korea

Abstract: The present study evaluates the incidence and mortality of vertebral fractures in Korea, using data from the Health Insurance Review Assessment Service, which includes nationwide information entrusted by Korean government. A vertebral compression fracture is a serious complication associated with osteoporosis of the spine. We evaluated the incidence of vertebral fracture and subsequent mortality in South Korea, using nationwide data from the Health Insurance Review and Assessment Service (HIRA). All new visits or admissions to clinics or hospitals for fractures were recorded in nationwide cohort by the Korean HIRA using International Classification of Disease, tenth Revision (ICD-10) code. The incidence of vertebral fracture and excess mortality associated with vertebral fracture were evaluated, in men and women aged 50 years or more between 2005 and 2008. Standardized mortality ratio (SMR) was calculated to determine excess mortality associated with vertebral fracture. The crude overall incidence of vertebral fractures was 984 per 100,000 person years from 2005 to 2008. The overall mortality rate at 3 months, 6 months, 1 year, and 2 years after vertebral fracture in men (5.56%, 9.41%, 14.6%, and 20.61%, respectively) were higher than that in women (2.41%, 4.36%, 7.16%, and 10.48%, respectively). In both genders, the age-specific mortality rates were more than those of the general population. The SMR was highest during the first 3 months and gradually declined to 2.53 in men and 1.86 in women at the 2-year period. The incidence of vertebral fracture in South Korea was comparable with other countries such as Switzerland, and the mortality after vertebral fracture is higher than that of normal populations. The incidence of osteoporotic vertebral fracture and following high mortality are likely to become serious socioeconomic problems.