Dae-Won Lee

Sex differences in the association between socio- economic status and type 2 diabetes: data from the 2005 Korean National Health and Nutritional Examination Survey (KNHANES)

OBJECTIVESnWhile socio-economic status (SES) is considered a key social-environment factor affecting health outcomes, sex differences in the association between SES and the risk of type 2 diabetes remain unclear. The aims of this study were: (1) to identify risk factors associated with type 2 diabetes in a representative sample of Korean adults with a focus on socio-economic determinants; and (2) to examine how the association between SES and type 2 diabetes is affected by sex.nnnSTUDY DESIGNnCross-sectional study.nnnMETHODSnThis study used data obtained from 3870 Korean adults (age ≥35 years) who participated in the 2005 Korean National Health and Nutritional Examination Survey (KNHANES III). The risk of type 2 diabetes in relation to SES was calculated, after controlling for other risk factors such as medical characteristics (hypertension, family history, body mass index, triglyceride, total cholesterol, high-density lipoprotein cholesterol), lifestyle factors (body mass index, smoking, alcohol intake, exercise) and perceived stress. Odds ratios (ORs) were calculated separately for Korean men and women using multivariate logistic regression.nnnRESULTSnCompared with individuals with ≥13 years of education, those with ≤6 years of education or 7-12 years of education had higher ORs for the risk of type 2 diabetes - 2.10 (95% confidence interval (CI) 1.27-3.48) and 1.62 (95% CI 1.04-2.52), respectively - after adjusting for age, sex, medical characteristics, lifestyle factors and stress level. The OR for women with ≤6 years of education was particularly high (OR 10.16, 95% CI 2.08-49.53), even after adjusting for the study covariates. However, this increasing trend in the OR was not observed for men.nnnCONCLUSIONSnSES significantly influences the risk of type 2 diabetes in Korean adults, and there are interactions with sex. Korean women with a low level of education represent a particularly high-risk group for type 2 diabetes. Future interventions should incorporate more targeted diabetes prevention efforts for women with a low level of education.

Preparation of Silica Coated Magnetic Nanoparticles for Bioseparation

Magnetic nanoparticles have been intensively developed and applied in several biomedical applications such as targeted delivery, drug therapy, hyperthermia, magnetic resonance imaging and bioseparation etc. This work describes a simple and convenient method to synthesize silica coated Fe3O4 nanoparticles which have the potential to be used in the bioseparation of fetuin from fetal bovine serum and albumin from the egg. In this work, uniform Fe3O4 particles were prepared through the one-pot solvothermal process at 200 °C for 12 h using a sole iron precursor (FeCl3 · 6H2O) and then were coated with SiO2 to prepare silica coated Fe3O4 nanoparticles by hydrolysis and condensation of tetraethyl orthosilicate in ethanol and H2O medium. We further characterized the synthesized Fe3O4 and Fe3O4@SiO2 using XRD, SEM, TEM, FT-IR and VSM to study phase purity, morphology, size, functionality and magnetic properties.

Preface: International symposium on catalytic conversion of energy and resources, 2016

An international symposium on catalytic conversion of energy and resources (ISCCER) was held in Seoul, Republic of Korea, from June 30 to July 2, 2016, as the satellite conference of the 16th international congress on catalysis (ICC). The symposium provided an encounter among the catalyst researchers with interest in the state-of-the-art scientific trends of the latest catalytic conversion processes of energy and resources to build the sustainable future. The symposium was attended by 228 participants from 11 nations. The program included 2 plenary lectures (Prof. Kazunari Domen and Prof. Alexis T. Bell), 6 keynote lectures, 5 invited lectures and 37 general oral presentations. Especially, the symposium was organized to comemorate the retirement of Professor Seong Ihl Woo from KAIST (Korea Advanced Institute of Science and Technology). Since Professor Woo obtained his MS degree at KAIST in 1975, for the last 40 years, he has investigated the structure of catalysts, reaction mechanisms, surface chemistry, reactor design, and reaction kinetics related to olefin polymerization, semiconductor materials and processing, environment protection and energy conversion. High-throughput screening (HTS) methodology augmented by artificial

Shape-controlled synthesis of magnetic Fe3O4 nanoparticles with different iron precursors and capping agents

This paper describes a modified method to prepare monodisperse Fe3O4 magnetic nanoparticles with different shapes (cube, octahedron, and sphere). The shape of the magnetic nanoparticles could be conveniently controlled by changing the types of precursor/capping agent and concentration of capping agent. The prepared samples were characterized using scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry. Cubes and octahedra were formed using ferrous sulfate heptahydrate as an iron source, ethylene glycol as a solvent and potassium hydroxide (KOH) as a capping agent while spheres were formed by using ferric chloride hexahydrate as an iron source, ethylene glycol as a solvent and ammonium acetate as a capping agent. By varying KOH concentration (0.5xa0M, 1 M, 1.5 M, and 5 M), the shape was transformed from cubes to octahedra because octahedra are developed dominantly at higher concentration of KOH within the reaction mixture. The magnetic studies show superparamagnetic behavior for all samples at room temperature. The Fe3O4 nanoparticles show the magnetic saturation values of 87 emu g−1, 85 emu g−1, and 82 emu g−1 for spheres, cubes, and octahedrons, respectively.

Analysis on Fluid Dynamics in the Cooling Tube for Manufacture of Liquid Hydrogen

We present a study of hydrogen liquefaction using the CFD (Computational Fluid Dynamics) program. Liquid hydrogen has been evaluated as the best storage method because of high energy per unit mass than gas hydrogen, but efficient hydrogen liquefaction and storage are needed in order to apply actual industrial. In this study, we use the CFD program that apply navier-stokes equation. A hydrogen is cooled by heat transfer with the while passing gas hydrogen through Cu tube. We change diameter and flow rate and observe a change of the temperature and flow rate of gas hydrogen passing through Cu tube. As a result of, less flow rate and larger diameter are confirmed that liquefaction is more well. Ultimately, When we simulate the hydrogen liquefaction by using CFD program, and find optimum results, it is expected to contribute to the more effective and economical aspects such as time and cost.