• Journal of Environmental Health Sciences
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• v.48 no.2
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• pp.96-105
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• 2022

Background: Pyrethroid insecticides account for more than 30% of the global insecticide market and are frequently used in agricultural settings and residential and public pest control among the general population. While several animal studies have suggested that exposure to pyrethroids can alter glucose homeostasis, there is only limited evidence of the association between environmental pyrethroid exposure and diabetes in humans. Objectives: This study aimed to report environmental 3-phenoxybenzoic acid (3-PBA) concentrations in urine and evaluate its association with the risk of diabetes in Korean adults. Methods: We analyzed data from the Korean National Environmental Health Survey (KoNEHS) Cycle 2 (2012~2014) and Cycle 3 (2015~2017). A total of 10,123 participants aged ≥19 years were included. Multiple logistic regressions were used to calculate the odds ratios (ORs) for diabetes according to log-transformed urinary 3-PBA levels. We also evaluated age, sex, education, monthly income, marital status, alcohol drinking, physical activity, urinary cotinine, body mass index, and sampling season as potential effect modifiers of these associations. Results: After adjusting for all the covariates, we found significant dose-response relationships between urinary 3-PBA as quartile and the prevalence of diabetes in pooled data of KoNEHS Cycles 2 and 3. In subgroup analyses, the adverse effects of pyrethroid exposure on diabetes were significantly stronger among those aged 19~39 years (p-interaction<0.001) and those who consumed high levels of cotinine (p-interaction=0.020). Conclusions: Our findings highlight the potential diabetes risk of environmental exposure to pyrethroids and should be confirmed in large prospective studies in different populations in the future.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.561-570
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• 2023

This study was to evaluate the effect of different rinsing times and methods on the accuracy of temporary prostheses fabricated by 3D printing method. Sixty temporary prostheses were fabricated with LCD types of 3D printer(Halot-Sky, Creality, Shenzhen, China) and divided into six groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5 and 10 min using three methods-hand washed, ultrasonic cleaning, and automated washing. All specimens were polymerized for 3 minutes under the same conditions. The marginal and internal gaps of specimens were examined using a replica technique. The light-body silicone thickness was measured at 6 reference points(Absolute marginal discrepancy, Marginal, Chamfer, Axial, Angle, and Occlusal gap). All measurements were performed by a stereomicroscope. Reference point images were taken at 100× magnification and then measured using an image analysis program. Statistical analysis was performed using Two-way ANOVA, One-way ANOVA, and the Kruskal-Wallis test (p = .05). The marginal and internal gaps were statistically different according to the rinsing methods and rinsing times(p < .001). In the rinsing time, the temporary prosthesis rinsed for 5 minutes group showed higher accuracy than 10 minutes group. In the rinsing method, the hand washing group showed higher accuracy than the automated washing group.

• Computers and Concrete
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• v.31 no.5
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• pp.433-442
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• 2023

This study presents the visually observed behavior of fibers embedded in concrete samples that were subjected to a flexural bending test. Three types of fibers such as macro polypropylene, macro polyethylene, and the hybrid of steel and polyvinyl alcohol were mixed with cement by a designated mix ratio to prepare a total of nine specimens of each. The bending test was conducted by following ASTM C1609 with a net deflection of 2, 4, and 7 mm. The X-ray computed tomography (XCT) was carried out for 7 mm-deflection specimens. The original XCT images were post-processed to denoise the beam-hardening effect. Then, fiber, crack, and void were semi-manually segmented. The hybrid specimen showed the highest toughness compared to the other two types. Debonding based on 2D XCT sliced images was commonly observed for all three groups. The cement matrix near the crack surface often involved partially localized breakage in conjunction with debonding. The pullout was predominant for steel fibers that were partially slipped toward the crack. Crack bridging and rupture were not found presumably due to the image resolution and the level of energy dissipation for poly-fibers, while the XCT imaging was advantageous in evaluating the distribution and behavior of various fibers upon bending for fiber-reinforced concrete beam elements.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.30-36
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• 2002

This study was conducted to evaluate the effect of regular exercise and other relating factors on the activities of erythrocyte antioxidant enzymes and plasma total radical-trapping antioxidant potential (TRAP) in 61 healthy male college students. The study population were divided in two groups ; small amount of exerciser (exorcise time less than 30min/d) and moderate amount of exerciser (exorcise time more than 30min/d) according to their physical exercise habits measured by a questionnaire. Dietary intake of vitamin C and vitamin E, Plasma lipid Profiles, erythrocyte superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and catalase activities, as well as plasma TRAP levels were determined. Plasma TRAP level was significantly higher in moderate amount of exercisers than that in small amount of exercisers. No significant differences were observed in erythrocryte SOD, catalase and GSH-Px between the two groups. Mean exercise time was positively correlated with the plasma level of TRAP significantly, and amount of alcohol consumption was negatively correlated with the erythrocyte SOD activity, Dietary vitamin C and I intakes did not correlated with either erythrocyte enzyme activities or plasma TRAP levels. There were positive correlations between plasma HDL-cholesterol, and erythrocyte GSH-Px or plasma TRAP levels. Plasma vitamin C concentrations was negatively correlated with plasma TRAP levels and erythrocyte SOD activity, however plasma vitamin C concentration was positively correlated with erythrocyte GSH-Px activity, The results would suggest that regular moderate exercise, nonsmoking, high HDL-cholesterol and high plasma vitamin E concentration enhance antioxidant defences against reactive oxygen species and may increase the likelihood of a healthier life span.

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.173-177
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• 2007

EB irradiation method was used to prepare polyvinyl alcohol (PVA) capped silver nanoparticles under various conditions including PVA concentration, $AgNO_3$ concentration, IPA concentration, and EB dosage. The increase in the distribution of particles size was observed with an increase in the concentrations of PVA, $AgNO_3$, IPA, and EB dosage. $AgNO_3$ concentration, IPA concentration, and EB dosage were found to have a great effect on the amount of silver particles formed in PVA matrix by EB irradiation method. These results were confirmed by XRD, UV, and TEM. XRD (X-ray diffraction) technique confirmed the zero valent state of silver. Optical studies were done using UV-visible spectrophotometer to see the variation of silver particles formed in PVA matrix. Transmission Electron Microscopic (TEM) was employed to show the particle size and distribution of silver foamed in PVA matrix.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.659-665
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• 2015

Loading of hydrophobic ${\alpha}$-tocopherol into nanostructured lipid carrier (NLC) was performed for improving its oxidative stability. First, various NLCs with different constituents and mixing ratios were prepared and their characteristics were investigated. While the stable NLCs were made when cetyl palmitate (CP) or glyceryl monosterate (GMS) was used as a solid lipid, the phase separation occurred in the NLCs consisting of stearic acid. Particle sizes of the NLCs were several hundreds of nanometers and the size decreased with increasing the ratio of solvent to lipid. It was examined from DSC thermogram and anisotropy test that the degree of crystallinity of the lipid phase decreased and the lipid matrix became less ordered when octyldodecanol, a long chain fatty alcohol, was added into the solid lipid. The oxidative stability of ${\alpha}$-tocopherol in NLC was remarkably improved compared to that in solution or emulsion under high temperature ($45^{\circ}C$) and UV radiation, which was verified through DPPH test and peroxide value measurement.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.976-986
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• 1997

Coronary artery disease (CAD) such as angina pectoris and myocardial infarction(MI) have been considered the major cause of death for decaddes . THeir incidence and prevalence are still increasing . Numerous studies have been done on the risk factor analysis of CAD in Western countries. Since the diet in Western countries is different from that in Korea it is difficult to assume that the Korean diet has the same effects as its western counterpeart on the development of CAD . THus the gudidelines for the Western CAD patients can no totally be applied to Koreans. This study was conducted to investigate the relationship between diet and CAD in Koreans. Subjects were comprised of patients admitted to the hospital for chest pain with poxxilbe CAD (men 129, women 65) . They were divided into the following three groups according to angiographic results ; angiogrphically normal coronary artery group (control), single vessel disease group(SVD) and multiple vessel disease group (MVD) . Intakes of dietary fatty acids and other nutrients were assessed by the semiquantitative food frequency method. Blood was also obtained from subjects for serum lipid analysis. Serum lipid profiles of men were clearly different form those of women. For men, serum choesterol levels (or LDL or LDL/HDL) seemed to be higher in the MVD group compared to the control and SVD groups, while TG level was significantly higher in the MVD group for women. Both men and women showed significantly higher caloric , fiber and vitamins C and A intakes in the MVD group than in the other two groups. Higher caloric intakes was due to higher intakes of carbohydrate and protein rather than fat intake. In terms of fatty acids intake, there were no significant differences among the three groups . Smoking seemed to have great effect on eating patterns in CAD patients. Smokers and ex-smokers showed significantly higher intakes of most nutrients including individual fatty acids that non-smokers. The results of stepwise regression showed that moderate alcohol intake decreases LDL levels and increases HDL levels and smoking seems to lowe HDL levels in CAD patients.

• Journal of Pharmacopuncture
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• v.17 no.1
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• pp.59-69
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• 2014

Objectives: In homeopathy, it is claimed that more homeopathically-diluted potencies render more protective/curative effects against any disease condition. Potentized forms of Condurango are used successfully to treat digestive problems, as well as esophageal and stomach cancers. However, the comparative efficacies of Condurango 6C and 30C, one diluted below and one above Avogadro's limit (lacking original drug molecule), respectively, have not been critically analyzed for their cell-killing (apoptosis) efficacy against lung cancer cells in vitro, and signalling cascades have not been studied. Hence, the present study was undertaken. Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were conducted on H460-non-small-cell lung cancer (NSCLC) cells by using a succussed ethyl alcohol vehicle (placebo) as a control. Studies on cellular morphology, cell cycle regulation, generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential (MMP), and DNA-damage were made, and expressions of related signaling markers were studied. The observations were done in a "blinded" manner. Results: Both Condurango 6C and 30C induced apoptosis via cell cycle arrest at subG0/G1 and altered expressions of certain apoptotic markers significantly in H460 cells. The drugs induced oxidative stress through ROS elevation and MMP depolarization at 18-24 hours. These events presumably activated a caspase-3-mediated signalling cascade, as evidenced by reverse transcriptase-polymerase chain reaction (RT-PCR), western blot and immunofluorescence studies at a late phase (48 hours) in which cells were pushed towards apoptosis. Conclusion: Condurango 30C had greater apoptotic effect than Condurango 6C as claimed in the homeopathic doctrine.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.3-13
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• 1987

Infrared absorption spectra of alkyl alcohols in the OH stretching region were obtained from varying the concentrations of alcohols in $CCl_4$. The OH stretching bands were broadened and shifted to lower frequencies due to the hydrogen-bond formation. Three bands were obtained from the breakdown of these bands by the simplex method. Each band was assigned to various types of hydrogen-bonded OH groups. The electronic structures and interaction energies of dimeric and trimeric alcohols were calculated by semi-empirical MO(CNDO/2, INDO) methods. These results were in good agreement with those of deconvoluted ir spectra. The EDA(electron donor-acceptor) effect of alkyl group on hydrogen-bond formation was in the decreasing order of butyl > propyl > ethyl > methyl group. On the other hand, the experimental results were in the order : propyl > ethyl > butyl > methyl group. This seemed to be ascribed to the bulkiness of butyl alcohol.

• Membrane Journal
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• v.13 no.2
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• pp.101-109
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• 2003

In the present study, crosslinked poly(vinyl alcohol) (PVA) membranes were prepared at various crosslinking agent content using sulfosuccinic acid (SSA) containing sulfonic acid group ($SO_3H)$. To reduce methanol permeability, silica was introduced to the membrane using sol-gel process. The hybrid membranes were studied in relation to proton conductivity and methanol permeability. It was found that both these properties were very dependent on the effect of SSA content as a crosslinking agent and as a donor of hydrophilic $SO_3H)$ group. The proton conductivities of these PVA/SSA/Silica membranes are in the range from $10^{-3}\;to\;10^{-2}$S/cm and the methanol permeabilities are in the range from $10^{-8}\;to\;10^{-7}\;cm^2/sec$.