Konkuk University

About: Konkuk University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Apoptosis. The organization has 13405 authors who have published 27027 publications receiving 506313 citations.

A nationwide survey on the prevalence of dementia and mild cognitive impairment in South Korea.

Abstract: We investigated the prevalence of dementia and mild cognitive impairment (MCI) and the factors associate with risk of dementia from a representative nationwide sample of Korean elders. 8,199 randomly-sampled Koreans aged 65 years or older were invited to participate in the Phase I screening assessment using Mini-Mental State Examination by door-to-door home visit, and 6,141 subjects (response rate = 74.9%) responded. Among them, 2,336 subjects were invited to participate in the Phase II diagnostic assessment for dementia and MCI, and 1,673 subjects responded (response rate = 71.6%). Diagnostic assessments were administered using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K) Clinical Assessment Battery. The CERAD-K Neuropsychological Assessment Battery was used for diagnosing MCI. Age-, gender-, education-, and urbanicity-standardized prevalence of dementia was estimated to be 8.1% (95% CI = 6.9-9.2) for overall dementia and 24.1% (95% CI = 21.0-27.2) for MCI. Alzheimer's disease (AD) was the most prevalent type (5.7%) followed by vascular dementia (2.0%). Amnestic subtype (20.1%) was much more prevalent than nonamnestic subtype in MCI (4.0%). Older age, being male, lower education level, illiteracy, smoking, and histories of head trauma or depression were associated with increased dementia risk, and alcohol use and moderately intense exercise were associated with decreased dementia risk. We expect numbers of dementia patients to double every 20 years until 2050 in Korea and expect AD to account for progressively more dementia cases in the future.

Novel chemical route for atomic layer deposition of MoS2 thin film on SiO2/Si substrate

Abstract: Recently MoS2 with a two-dimensional layered structure has attracted great attention as an emerging material for electronics and catalysis applications. Although atomic layer deposition (ALD) is well-known as a special modification of chemical vapor deposition in order to grow a thin film in a manner of layer-by-layer, there is little literature on ALD of MoS2 due to a lack of suitable chemistry. Here we report MoS2 growth by ALD using molybdenum hexacarbonyl and dimethyldisulfide as Mo and S precursors, respectively. MoS2 can be directly grown on a SiO2/Si substrate at 100 °C via the novel chemical route. Although the as-grown films are shown to be amorphous in X-ray diffraction analysis, they clearly show characteristic Raman modes (E12g and A1g) of 2H-MoS2 with a trigonal prismatic arrangement of S–Mo–S units. After annealing at 900 °C for 5 min under Ar atmosphere, the film is crystallized for MoS2 layers to be aligned with its basal plane parallel to the substrate.

Multidimensional effects of biologically synthesized silver nanoparticles in Helicobacter pylori , Helicobacter felis , and human lung (L132) and lung carcinoma A549 cells

Abstract: Silver nanoparticles (AgNPs) are prominent group of nanomaterials and are recognized for their diverse applications in various health sectors. This study aimed to synthesize the AgNPs using the leaf extract of Artemisia princeps as a bio-reductant. Furthermore, we evaluated the multidimensional effect of the biologically synthesized AgNPs in Helicobacter pylori, Helicobacter felis, and human lung (L132) and lung carcinoma (A549) cells. UV-visible (UV–vis) spectroscopy confirmed the synthesis of AgNPs. X-ray diffraction (XRD) indicated that the AgNPs are specifically indexed to a crystal structure. The results from Fourier transform infrared spectroscopy (FTIR) indicate that biomolecules are involved in the synthesis and stabilization of AgNPs. Dynamic light scattering (DLS) studies showed the average size distribution of the particle between 10 and 40 nm, and transmission electron microscopy (TEM) confirmed that the AgNPs were significantly well separated and spherical with an average size of 20 nm. AgNPs caused dose-dependent decrease in cell viability and biofilm formation and increase in reactive oxygen species (ROS) generation and DNA fragmentation in H. pylori and H. felis. Furthermore, AgNPs induced mitochondrial-mediated apoptosis in A549 cells; conversely, AgNPs had no significant effects on L132 cells. The results from this study suggest that AgNPs could cause cell-specific apoptosis in mammalian cells. Our findings demonstrate that this environmentally friendly method for the synthesis of AgNPs and that the prepared AgNPs have multidimensional effects such as anti-bacterial and anti-biofilm activity against H. pylori and H. felis and also cytotoxic effects against human cancer cells. This report describes comprehensively the effects of AgNPs on bacteria and mammalian cells. We believe that biologically synthesized AgNPs will open a new avenue towards various biotechnological and biomedical applications in the near future.