• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.6
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• pp.250-255
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• 2006

The synthesis and characterization of silver colloidal nanoparticles by chemical reduction of silver ions in aqueous $AgNO_3$ using sodium borohydride $(NaBH_4)$ as the reducing agent are described. The experimental conditions for aggregation and paricle size of nanosilver particles in water is investigated in terms of concentration of $NaBH_4$, reaction temperature, dropping rate of $AgNO_3$ and concentration of laponite. Stable nanosilver sol is obtained at three molar ratio of $NaBH_4/AgNO_3$ in conditions of without laponite. The size of nanosilver particles is increased as the reaction temperature is increased. The large size of nanosilver sol is obseved as the dropping rate of $AgNO_3$ is increased due to the aggregation of initial high local concentration of nanosilver particles. Stable nanosilver sol at high temperature $(>\;100^{\circ}C)$ can be prepared when laponite is used as protective colloid.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.57-63
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• 2007

Soil aggregation has been considered as an important factor not only for increasing soil productivity and soil quality but also improving nutrient use availability and water use efficiency. However, the relationship between soil aggregation and soil properties hasn't well reported for Korean soils. Objective of this research was to identify the relationship among soil water-stable aggregate (WSA), soil properties and soil dispersion ratio. Soil samples were analyzed for water-stable aggregate, Middleton's dispersion ratio, and soil physical and chemical properties. Water-stable aggregate was significantly correlated to soil textural properties, soil organic matter, and exchangeable cations. Middleton's dispersion ratio was significantly correlated with water-stable aggregate ($r=-0.76^{***}$). Regression equation for water-stable aggregate was estimated by Middleton's dispersion ratio (Y=-0.79X + 96.49; $r^2=0.58^{**}$). In this research, we conclude that water-stable aggregate was significantly correlated with some soil properties and was able to be estimated by rapid and easily measurable Middleton's dispersion ratio.

• Journal of Nutrition and Health
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• v.27 no.4
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• pp.323-335
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• 1994

The present study was carried out in normocholesterolemic New Zealand white(NZW) rabbit, to evaluate the effect of dietary supplementation with Korean pinenut oil, on plasma lipids, plasma lipoproteins, liver lipids and platelet aggregation. NZW rabbits were fed for 80 days on a commercial chow diet supplemented with 5% of energy as fats(soybean oil or pinenut oil) or 10% of energy as fats(soybean oil or pinenut oil). A control group was fed a commercial stock diet. There were no significant effects of pinenut oil on plasma free cholesterol, HDL-cholesterol, triglycerides, glucose and lecithin-cholesterol acyltransferase, as compared with those obtained from rabbits fed the soybean oil diet. After 80 days, the concentration of plasma free fatty acid in only the pinenut oil group was significantly decreased by about 50% relative to the control diet. At the end of the dietary treatment, liver triglycerides and phospholipids were significantly decreased in the pinenut oil group, compared to the how diet, whereas the soybean oil-consuming rabbits had only significantly decreased phospholipid levels. Cholesterol contents of liver were unaffected by type of dietary fat. At the end of 80 days, a diet containing pinenut oil resulted in a decrease in apolipoprotein B and the apo B/apo AI ratio as compared with the stock diet or soybean oil diet. Platelet aggregation induced by collagen or arachidonic acid was depressed significantily in pinenut oil diet.

• Journal of Adhesion and Interface
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• v.12 no.1
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• pp.1-10
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• 2011

An automated reaction calorimeter was used to directly monitor the rate of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) (PVAs) having different degrees of blockiness. By using this technique in conjunction with other off-line measurements of the evolution of particle size distributions, important details of the process were observed. No constant graft rate period was observed for both low and high initial monomer-water ratios. The gel effect was observed for the low monomer-water ratio recipe. The particle size distributions were broad (particle diameter 40~100 nm) and bimodal. Continuous nucleation was observed to be accompanied by 'limited aggregation' and flocculation during the particle growth stages. It was speculated to be due to the occurrence of the extensive 'limited aggregation' and chain transfer to PVA leading to grafting.

• ETRI Journal
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• v.45 no.1
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• pp.45-59
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• 2023

In this paper, to optimize the average delay and power allocation (PA) for system users, we propose a resource scheduling scheme for wireless networks based on Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) according to the first fifth-generation standards. For delay minimization, we solve a throughput maximization problem that considers CPOFDM systems with carrier aggregation (CA). Regarding PA, we consider an approach that involves maximizing goodput using an effective signal-to-noise ratio. An algorithm for jointly solving delay minimization through computation of required user rates and optimizing the power allocated to users is proposed to compose the resource allocation approach. In wireless network simulations, we consider a scenario with the following capabilities: CA, 256-Quadrature Amplitude Modulation, millimeter waves above 6 GHz, and a radio frame structure with 120 KHz spacing between the subcarriers. The performance of the proposed resource allocation algorithm is evaluated and compared with those of other algorithms from the literature using computational simulations in terms of various Quality of Service parameters, such as the throughput, delay, fairness index, and loss rate.

• Nutrition Research and Practice
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• v.1 no.4
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• pp.298-304
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• 2007

This study was conducted to investigate the hypocholesterolemic effect of simvastatin (30 mg/kg BW) and antioxidant effect of coenzyme Q10 (CoQ10, 15 mg/kg BW) or green tea (5%) on erythrocyte Na leak, platelet aggregation and TBARS production in hypercholesterolemic rats treated with statin. Food efficiency ratio (FER, ADG/ADFI) was decreased in statin group and increased in green tea group, and the difference between these two groups was significant (p<0.05). Plasma total cholesterol was somewhat increased in all groups with statin compared with control. Plasma triglyceride was decreased in statin group and increased in groups of CoQ10 and green tea, and the difference between groups of statin and green tea was significant (p<0.05). Liver total cholesterol was not different between the control and statin group, but was significantly decreased in the group with green tea compared with other groups (p<0.05). Liver triglyceride was decreased in groups of statin and green tea compared with the control, and the difference between groups of the control and green tea was significant (p<0.05). Platelet aggregation of both the initial slope and the maximum was not significantly different, but the group with green tea tended to be higher in initial slope and lower in the maximum. Intracellular Na of group with green tea was significantly higher than the control or statin group (p<0.05). Na leak in intact cells was significantly decreased in the statin group compared with the control (p<0.05). Na leak in AAPH treated cells was also significantly reduced in the statin group compared with groups of the control and CoQ10 (p<0.05). TBARS production in platelet rich plasma was significantly decreased in the groups with CoQ10 and green tea compared with the control and statin groups (p<0.05). TBARS of liver was significantly decreased in the group with green tea compared with the statin group (p<0.05). In the present study, even a high dose of statin did not show a cholesterol lowering effect, therefore depletion of CoQ10 following statin treatment in rats is not clear. More clinical studies are needed for therapeutic use of CoQ10 as an antioxidant in prevention of degenerative diseases independent of statin therapy.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.488-494
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• 2010

Under W/O emulsion method using a homogenizer, ${\alpha}$-alumina powder was prepared to evaluate the effects of experimental conditions on its properties, such as particle shape, extent of aggregation, average particle size and distribution. The experimental parameters were the change of type, quantity and composition of emulsifiers as well as the change of O : W volumetric ratio and agitation rate. As results, in the case of the use of single surfactant of SP80, sphere-like particles could be prepared and the average particle size was hardly affected by the agitation speed more than 16000 rpm regardless of SP80 quantity used. When the extent of aggregation among sphere-like particles prepared using $HLB_m$ = 5 of [SP80 & TW80] was compared with that prepared using SP80 at the same vol% surfactant and agitation speed, the former showed more or less low aggregation phenomena and average particle size was slightly reduced. In addition, the fraction of nano-sized particles with low aggregation was increased by the use of 0.1 vol% n-butanol, as a co-surfactant, with $HLB_m$ = 5 of [SP80 & TW80].

• Translational and Clinical Pharmacology
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• v.26 no.4
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• pp.160-165
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• 2018

Indobufen ($Ibustrin^{(R)}$), a reversible inhibitor of platelet aggregation, exists in two enantiomeric forms in 1:1 ratio. Here, we characterized the anti-platelet effect of S- and R-indobufen using response surface modeling using $NONMEM^{(R)}$ and predicted the therapeutic doses exerting the maximal efficacy of each enantioselective S- and R-indobufen formulation. S- and R-indobufen were added individually or together to 24 plasma samples from drug-naïve healthy subjects, generating 892 samples containing randomly selected concentrations of the drugs of 0-128 mg/L. Collagen-induced platelet aggregation in platelet-rich plasma was determined using a Chrono-log Lumi-Aggregometer. Inhibitory sigmoid $I_{max}$ model adequately described the anti-platelet effect. The S-form was more potent, whereas the R-form showed less inter-individual variation. No significant interaction was observed between the two enantiomers. The anti-platelet effect of multiple treatments with 200 mg indobufen twice daily doses was predicted in the simulation study, and the effect of S- or R-indobufen alone at various doses was predicted to define optimal dosing regimen for each enantiomer. Simulation study predicted that 200 mg twice daily administration of S-indobufen alone will produce more treatment effect than S-and R-mixture formulation. S-indobufen produced treatment effect at lower concentration than R-indobufen. However, inter-individual variation of the pharmacodynamic response was smaller in R-indobufen. The present study suggests the optimal doses of R-and S-enantioselective indobufen formulations in terms of treatment efficacy for patients with thromboembolic problems. The proposed methodology in this study can be applied to the develop novel enantio-selective drugs more efficiently.

• Journal of Nutrition and Health
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• v.41 no.5
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• pp.381-390
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• 2008

Present study was conducted to investigate the effects of exercise and cholesterol diet on plasma and liver lipids, platelet aggregation, erythrocyte Na efflux and liver index such as GOT and GPT using Sprague Dawley rats. Forty rats were divided into four groups and fed control or 0.5% cholesterol diet with and without treadmill for six weeks. The final body weight of group fed cholesterol diet with exercise was somewhat decreased compared with group fed cholesterol diet without exercise. L.W/B.W ratio was significantly increased in groups fed cholesterol diet (p < 0.01), but exercise tended to decrease this ratio. Plasma total cholesterol was significantly increased and HDL-cholesterol was decreased in groups fed cholesterol diet (p < 0.01). Plasma triglyceride was significantly decreased in groups fed cholesterol diet compared with groups fed control diet (p < 0.01). Plasma triglyceride of groups with exercise was significantly decreased compared with their non exercising counterparts regardless diet (p < 0.05). Liver total cholesterol and triglyceride was significantly increased in groups fed cholesterol diet (p < 0.01), but exercise did not affect on these levels. Na-K ATPase was somewhat decreased in groups fed cholesterol diet, and exercise tended to recover the reduced Na-K ATPase. Na passive transport was significantly decreased in group fed control diet without exercise and significantly increased in group fed cholesterol diet with exercise, there were significant differences between groups (p < 0.05). There were no differences in total Na efflux and intracellular Na among groups, and total Na efflux was not correlated with intracellular Na. Hematocrit was significantly lower (p < 0.05) in group fed cholesterol diet without exercise compared with other groups. Platelet aggregation in the initial slope and the maximum was increased in groups fed cholesterol diet, but not statistically significant. Exercise especially increased the initial slope of aggregation. Plasma GOT and GPT was significantly increased in groups fed cholesterol diet (p < 0.01), and exercise in group fed cholesterol diet significantly decreased both GOT and GPT compared with the non exercising counterpart (p < 0.01). This study showed that cholesterol diet increases plasma and liver lipids and GOT and GPT, and exercise improves plasma and liver lipid profile and liver index of GOT and GPT preventing fatty liver.

• Journal of Preventive Medicine and Public Health
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• v.19 no.1 s.19
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• pp.91-99
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• 1986

To determine relationships of supposed risk factors to positives for HBsAg and Anti-HBs and also relationships of subjective symptoms to positives for HBsAg and Anti-HBs, study of 658 people working in the hospital, university, bank and other office was performed. Positive rate for HBsAg was about 7.9% and positive rate for Anti-HBs was about 20.0%. Odds ratio of HBsAg was high and significant in individuals who are married and who have previous hepatitis B(P<0.001), medical personnel in family, more than 4 people in a room(0.01