• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.281-295
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• 2021

In this study, the direct amination of ethanol was performed over impregnated Ni on SiO2-Al2O3 mixed oxide catalysts prepared by varying Si/(Si + Al) molar ratio to 30 mol%. To characterize the physico-chemical properties of the catalysts used, X-ray diffraction (XRD), N2-physisorption, temperature-programmed desorption of iso-propyl alcohol (IPA-TPD), temperature-programmed desorption of ethanol (EtOH-TPD), temperature-programmed reduction with H2 (H2-TPR), H2-chemisorption and transmission electron microscopy (TEM) were used. The acidic property was continuously increased until Si/(Si + Al) = 30 mol% in SiO2-Al2O3 mixed oxides used. The dispersion of Ni metal and surface area, acid characteristics of the supported Ni catalyst have a complex effect on the catalytic reaction activity. The low reduction temperature of nickel oxide and acidic properties were beneficial to the formation of acetonitrile. In terms of conversion of ethanol, Ni/SiO2-Al2O3 catalyst with a molar ratio of 10 mol% Si/(Si+Al) showed the highest activity and a volcanic curve based on it. The tendency of results were consistent in the metal dispersion and catalytic activity.

• Journal of Conservation Science
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• v.35 no.2
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• pp.159-168
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• 2019

Plasticizers, which are added to plastics, can cause exudation, which means that the plasticizer comes out from surface of the plastics. This causes the surface of plastic artworks to become sticky, and this allows dust and pollutants to become attached to the surface. Therefore, in this study, the degradation characteristics and chemical cleaning methods of each type of plasticizer are evaluated using PVC specimens. To evaluate the degradation characteristics and chemical cleaning methods, microscopic observation, chromaticity and weight measurement, and FT-IR spectroscopy were performed. The results showed that PVCs containing different plasticizers have different degradation patterns. Especially, the PVC containing TOTM showed discoloration and exudation. In the evaluation of the chemical cleaning methods, ethyl alcohol and KOH solution showed good effects, but their stability was not good. Surfactant was found to have a good cleaning effect and stability as a cleaner for exudated plasticizers.

• Journal of radiological science and technology
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• v.35 no.1
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• pp.9-15
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• 2012

The purpose of this study is to provide preliminary data for bone disease prevention by examining the correlation between bone mineral density, and lifestyle and nutritional status of female shift workers, at general hospitals with an irregular life cycle. The subjects for this study were 232 female shift workers, over 30 years old, who worked at a general hospital more than 5 years. From the subjects, who understood the purpose of this study and decided to be participated, we measured serum albumin, total brotein, total cholesterol, hematocrit, hemoglobin, calcium, phosphorus from blood test, and obtained bone mineral density. To analyze the effectiveness of the variables for explanation power, we established the studied values as independent variables, bone minral density as a dependent variable. Exercise, the number of drinking, calcium, and phosphorus were selected as significant variables and the explanation power was 10.2%. The bone mineral density were significantly higher at the subjects who had exercise, higher calcium and phosphorus possession, and drank alcohol than the opposite cases. Regular exercise, and 1:1 intake of calcium and phosphorous were important to prevent osteoporosis for the subjects who were working three shifts which cause irregular lifestyle.

• KSBB Journal
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• v.4 no.1
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• pp.40-47
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• 1989

Changes of principal components of crude green tea were determined after 30 min. of heat treatment at 10$0^{\circ}C$, l15$^{\circ}C$, 14$0^{\circ}C$, 16$0^{\circ}C$. Four kinds of free sugars(sucrose, fructose, glucose, raffinose) and an unidentified sugar compound were separated in green tea by using High Performance LiQuid Chromatography (H.P.L.C.). 26-34 peaks were isolated as aroma compounds of green tea by means of Gas Liquid Chromatography(G.L.C). The typical aroma component of green tea such as linalool, furfural, benzyl alcohol and 13 other substances were identified. Contents of most compounds were decreased by heat treatment. Especially contents of free amino acids, free sugars, vitamin C and tannins were decreased remarkably, while those of total nitrogen and soluble nitrogen were hardly changed. The effect of heat treatment on organoleptic quality of tea extracts were examined by sensory evaluation of which result indicated the most favorable tea was produced at 115$^{\circ}C$. The Percentages of loss in contents of total sugars, reducing sugars, vitamin C, free amino acids and tannins at 115$^{\circ}C$ were 17%, 16%, 36%, 12% and 15% respectively, while those were 38%, 53%, 55%, 74% and 23% at 16$0^{\circ}C$.

• Journal of Yeungnam Medical Science
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• v.13 no.2
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• pp.261-271
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• 1996

Introduction: Osteoporosis, the most common metabolic bone disorder, is a condition of reduced bone density and increased susceptibility to fractures. Osteoporosis is a major public health problem and a significant cause of morbidity in postmenopausal women. Therefore family physicians as primary care physicians are in a key position for preventing and treating this disorder. So we studied the factors affecting to bone mineral density in postmenopausal women. Materials and Methods: A total of 136 spontaneous postmenopausal women were participated in the study. They have measured spinal bone mineral density by dual energy x-ray absorptiometry from January 1992 to June 1995 at Yeungnam University Hospital. Age, height, weight, age at menarche and menopause, number of child and breast feeding child, history of oral pill ingestion, family history of osteoporosis, amount of milk and coffee ingestion, consumption of tobacco and alcohol and physical activity were assessed by qustionnaire and medical records. Results: The mean age is 55.2 and mean age at menopause is 47.9. Height, weight and physical activity were significantly positive correlated to bone mineral density. But age, duration after menopause and number of child were significantly negative correlated. Also age, height, weight, physical activity and duration after menopause were significantly correlated to % age-matched bone mineral density. In multiple regression analysis, which dependent variable is bone mineral density, duration after menopause, physical activity and weight were significant contributors. Duration after menopause is most the largest contributor. In multiple regression analysis, which dependent variable is % age-matched bone mineral density to adjust the age effect, physical activity and weight were significant contributors. Physical activity is most the largest contributor. Conclusions: Among factors affecting to BMD in postmenopausal women, physical activity and weight were more important factors. Therefore continuous physical activity is significant factor to prevent osteoporosis in postmenopausal women.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.131-135
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• 2008

Purpose: To measure and quantify the factors of intraocular pressure (IOP) variation for normal Korean youth. Methods: The IOP of normal youth 805 persons (male: 367, female: 438) were measured as a function of time and quantity for fixation, reclining posture, hard blinking, drinking water, drinking hard liquor, tobacco and coffee by using non-contact tonometer (AT555, Reichert Co.). In the case of fixation, reclining posture and hard blinking, the intraocular pressure of right and left eye were measured for 6 males and 6 females every 10 minutes during 30 minute. In the case of water, liquor, tobacco and coffee, the measurement for 4 or 5 groups (6 persons/ group) having similar IOP were done for the IOP variation of right eye. Results: The mean IOP was 15.2 mmHg for males and 15.8 mmHg for females (slightly higher than male's), respectively and the 99% of those were in the range of the normal IOP. The measured IOP was increased by fixation, reclining posture and hard blinking with males and females. The gradient of increasing slope was 0.15/0.13/0.07/0.08, 0.09/0.08/0.08/0.08 and 0.19/0.08/0.26/0.31, respectively. The IOP variation was elevated by drinking water (especially in the case of 1000 ml) and lowered in proportion to the amount of drinking by hard liquor. Cigarette smoking was associated with rise in intra ocular pressure, but was not shown a definite relation. And coffee had virtually no effect. Conclusions: Fixation, reclining posture, hard blinking and Tobacco caused a transient increase in IOP, but alcohol elicited a slight reduction in IOP overall.

• Journal of dental hygiene science
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• v.15 no.4
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• pp.413-418
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• 2015

Recent cross-sectional studies indicate that obesity is a risk factor for periodontal disease. This study was aimed to investigate whether the four-week weight control program including caloric restriction and exercise training could have an effect on periodontal health. Forty-one obese (body mass index [BMI] ${\geq}25.0$) and five overweight ($23.0{\leq}BMI<25.0$) students participated in the weight control program. Anthropometric data and oral examination data were collected at the baseline and at the 27th day. BMI, waist hip ratio (WHR), and percent of body fat (PBF) of the subjects decreased significantly, but gingival index, sites with bleeding on probing (BOP), and sites with shallow pocket depth didn't show the significant changes in paired t-test. There was no difference in the outcomes according to smoking, drinking alcohol, and sex. Nevertheless, PBF and sites with BOP (r=0.777) and WHR and sites with shallow pocket depth (r=0.444) showed positive correlations. PBF accounted for 58.9% of the variance in sites of BOP in regression analysis. We suggested that obesity might relate with periodontal health, although it was not clear whether weight control could influence on periodontal health directly.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1208-1213
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• 2016

Advanced glycation end product (AGE) formation and reactive oxygen species are potential therapeutic targets for the prevention of diabetic nephropathy and other pathogenic complications. Activity-guided isolation of an ethylacetate-soluble portion of 80% methanolic extract from fruits of Sorbus commixta of the Ulleung Island origin using AGE formation inhibition assay led to the isolation and identification of three caffeoylquinic acid derivatives of a previously known structure, 3-O-caffeoylquinic acid (neochlorogenic acid; 1), 4-O-caffeoylquinic acid (cryptochlorogenic acid; 2), and 5-O-caffeoylquinic acid (chlorogenic acid; 3). The structures of these compounds were confirmed by interpretation of nuclear magnetic resonance and mass spectrometry data. Among the isolates, the major metabolite, neochlorogenic acid (1) showed the most potent inhibitory effect against AGE formation with an $IC_{50}$ value of $167.5{\pm}3.5{\mu}M$. Furthermore, all isolated chlorogenic acid isomers were evaluated for their radical scavenging activity against peroxynitrite, and structurally related isomers 1, 2, and 3 exhibited potent inhibitory effects in this radical scavenging assay. This result suggests that the monocaffeoyl quinic acid derivatives isolated from S. commixta might be beneficial for the regulation of diabetic complications and related diseases.

• Polymer(Korea)
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• v.24 no.1
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• pp.82-89
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• 2000

The blood compatibilities of PU/PVA polymer blends with different mixing ratios were evaluated using various methods, such as fibrinogen adsorption, plasma recalcification time, platelet adhesion, whole blood clotting time, and complement activation. In addition, PVA on the surface of the polymer blends was crosslinked by glutaraldehyde to restrain the mobility of PVA molecules for characterizing the effect of PVA in the polymer blends on blood compatibility. The fibrinogen adsorption on the polymer blends decreased with the increase of PVA amount in the polymer blends. The plasma recalcification times of the polymer blends with 10-50 wt% PVA were longer than those of PU, PVA, and polymer blends with higher amount of PVA. The morphological changes and adhesion of platelets on the polymer blends with 30-50 wt% PVA were less than those on the other materials. The blood clotting times and complement activation on the polymer blends with 30-50 wt% PVA were reduced, compared to the other materials. On the other hand, the blood compatibility of the crosslinked polymer blends was relatively decreased, compared to the non-crosslinked ones. According to these experimental results, the blood compatibility of the polymer blends with 30-50 wt% PVA was better than that of the other materials and such a blood compatibility of the polymer blends might be related to the mobility of PVA molecules on the surface.

• Clean Technology
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• v.17 no.4
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• pp.336-345
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• 2011

The total area of forest land in Korea is 64.2%, and significant forest resources can continuously be produced. However our country didn't separate the recyclable waste wood and was illegal landfill or incinerated. In this study, waste-wood and rice husk of biomass and low-grade-anthracite made refuse derived fuel by mixing and compressing. In addition, the binding effect of binders and additives were analyzed. Physical and chemical characteristics of manufactured refuse derived fuel were analyzed and evaluated suitability by compared with quality standards. A result of change with compressed and relaxed density, added 20% anthracite and 10% rice husk is optimal density change and average density increased large range when 20 wt.% P.V.A., guargum, molasses and 10 wt.% starch were added. All fuel samples be distributed over 3,500 kcal/kg LHV and grade of No. 3~4 fuels appeared. A result of the characteristics of physical and chemical compressed biomass refuse derived fuel with addictive, 12.9% of durability improvement appeared when is mixing asphalt and 5.8% of durability improvement appeared when is mixing rice bran by pretreatment of NaOH 5%.