• Macromolecular Research
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• v.12 no.1
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• pp.63-70
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• 2004

We have synthesized various types of poly(ethylene glycol) (PEG)-ibuprofen conjugates by the nucleophilic substitution of bromo-terminated PEG with ibuprofen-Cs salt; PN (Pluronic) was also used in place of PEG. All the bromo-terminated PEGs and PN were obtained in high yield. Conversions of the terminal hydroxyl groups to bromo-termini were quantitative, as were the drug conjugation processes. The Ι$_1$/Ι$_3$values obtained from solutions of the ibuprofen-conjugated prodrugs are summarized in relation to those of ibuprofen in water and in aqueous solutions of the original PEG, PN, and several ordinary surfactants. We believe that the fully hydrophilic PEG is completely hydrated and forms no hydrophobic pocket by segment aggregation. These results indicate that the probe environment is significantly hydrophobic, particularly in the solution of prodrug PN, for which the ratio is similar to that obtained from typical micelles of surfactants. The results suggest, therefore, that the present synthetic method is very useful for preparing PEG-based prodrugs from pharmaceuticals having carboxyl functionalities.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.15-23
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• 2002

Gender differences in the effects of gonadectomy and high cholesterol diet on body weight and body cholesterol were investigated by using Sprague Dawley rats. Body weight, plasma and liver levels of cholesterol and triglyceride and platelet aggregation were examined in ovariectomized(OVX) or orchidectomized(ODX) rats with their intacts after feeding diet with or without 0.5% cholesterol. Body weight was significantly increased(p < 0.01) in OVX rats and significantly decreased(p < 0.01) in ODX rats compared to their respective intact rats, and cholesterol diet significantly(p < 0.05) decreased body weight in gonadectomized rats. Liver lobes from rats fed cholesterol diet were opaque and larger than those from rats find control dict, resulting in a significant increase(p < 0.01) in LW/BW ratio. Plasma and liver levels of total cholesterol were significantly increased (p < 0.01) in female rats regardless ovariectomy when find 0.5% cholesterol diet, but those levels in male rats were increased only when they were orchidectomized(p < 0.0l). Plasma HDL-cholesterol was significantly decreased(p < 0.05) in both sexes when find cholesterol diet. HDL-cholesterol were higher in female than male rats regardless treatments(p < 0.05). Liver triglyceride was significantly increased(p < 0.05) in both sexes when find cholesterol dict. Plasma level of triglyceride was not different among groups except significant decrease(p < 0.05) in cholesterol find ODX rats. Maximum platelet aggregation in female rats was significantly lower(p < 0.05) than male, but ovariectomy and cholesterol diet caused an increase te the level of male rats. Microscopic examination showed cholesterol diet caused a lipid accumulation in liver. Results indicate that intact female rats have higher response to hypercholestcrolemic diet than intact male rats and orchidectomy causes male rats more responsive to hypercholesterolemic diet. However, ovariectomy causes an increase female food efficiency ratio to the level of male rats, significantly increasing body weight.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.131-137
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• 2005

Seasonal occurrence of the egg parasitoid of bugs, Ooencyrtus nezarae (Hymenoptera: Encyrtidae), was monitored at soybean fields and university campus using traps baited with aggregation pheromone of bean bug, Riptortus clavatus, in Jinju, Gyeongnam province, Korea. The female O. nezarae captured at university campus in 2003 and 2004 was 317.5 and 103.4 times as many as males, respectively, and it was 12.6 times at soybean field in 2004. The female began to occur from late August, showing its peak around September 20 at soybean field in 2004. At university campus in 2003 and 2004, the female began to occur from mid or late August, and showed its peak early or mid September. At the two monitoring sites the catches of female sharply declined after October The E2HZ3H only showed attractiveness to O. nezarae, among three components of the aggregation pheromone of bean bug, (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and myristyl isobutyrate (MI). A mixture in a ratio of 20:20:10 or 16.7:16.7:16.7 of E2HZ3H:E2HE2H:MI attracted significantly more females than the mixture of 7:36:7 ratio did. This higher attractiveness of the former two blends may be attributed to the higher amounts of E2HZ3H in the blends.

• Korean journal of applied entomology
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• v.51 no.4
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• pp.411-419
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• 2012

The lure-distance of Riptortus pedestris aggregation pheromone was elucidated and the damage mitigation effect by mass trapping of R. pedestris was examined in commercial soybean fields. The recaptured ratio showed that 76.1% of total recaptured individuals were lured within 40 m and 89.0% of total recaptured adults were arrested in the lower 80 m. There is not much difference in the number of recaptured individuals according to the location of installed traps in the experiment. There was linear correlation between the total installed number of traps and the total number of trapped individuals in commercial soybean fields. and the highest yield (261.8 g/10 stems) was investigated in the field that had installed a pheromone trap per $770m^2$. No relationship wasf found between the covered areas of a pheromone trap for mass trapping and yield loss. The ratio of type A seed (healthy) was higher in the field that installed a trap per $385m^2$ and $770m^2$ (around 62%) and type B seed (showing distinct injury marks) was lower in the same fields (around 27%). From this result, we could reduce slightly the damage of soybean seeds by the mass trapping of Riptortus pedestris adults with an aggregation pheromone trap per $385{\sim}770m^2$ area range.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.73-76
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• 2005

This study aims to suggest a simple and convenient design for a mix proportion method for high performance concrete by determining the optimum fine aggregate ratio and minimum binder content based on the maximum density theory. The mix design method introduced in this study adopted the optimum fine aggregate ratio with a minimum void and binder content higher than the minimum binder content level. The research results reveal that the method helps to reduce trial and error in the mixing process and is a convenient way of producing high performance concrete with self filler ability. In an experiment based on the mix proportion method, when aggregate with the fine aggregation ratio of 41$\%$ was used, the minimum binder content of high performance concrete was 470kg/$m^{3}$ and maximum aggregate capacity was $0.657m^{3}/m^{3}$. In addition, in mixing high performance concrete, the optimal slump flow to meet filler ability was 65$\pm$5cm, V load flow speed ranged from 0.5 to 1.5.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.48-48
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• 2002

Glutathione (GSH) is most prevalent reducing thiols in eukaryotic cells and known that participates in many cellular processes. It was found that total amount of glutathione and the ratio of reduced to oxidized glutathione during development of Dictyostelium discoideum increase at the initial stage of the aggregation of amoeba.(omitted)

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1555-1559
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• 2005

High-performance fluorescent probes which exhibit either on/off or dual color fluorescence switching in response to the presence of organic vapors with a rapid response, a high sensitivity and a high-contrast on/off signaling ratio were demonstrated on the basis of the vapor-controlled AIEE phenomenon.

• Tuberculosis and Respiratory Diseases
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• v.40 no.2
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• pp.147-152
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• 1993

Background: There is evidence that platelet is activated in chronic obstructive pulmonary disease and activated platelet with injured endothelium contribute to the pathogenesis of pulmonary hypertension, prognostic factor of chronic obstructive pulmonary disease. So, we have investigated platelet function further in chronic obstructive pulmonary disease and effect of platelet activation on pulmonary hypertension. Method: We studied platelet aggregation ratio and alpha-granule products such as platelet factor 4(PF4) and beta-thromboglobulin (${\beta}$-TG) in control subjects and COPD without and with pulmonary hypertension subjects. Result: 1) The platelet aggregation ratio (PAR) was $0.99{\pm}0.04$ in control subjects, $0.98{\pm}0.05$ in COPD without pulmonary hypertension subjects and $0.89{\pm}0.08$ in COPD with pulmonary hypertension subjects. The platelet aggregation ratio of COPD subjects was tend to decrease than that of control subjects and the ratio of COPD with pulmonary hypertension subjects was significantly lower than that of control subjects. 2) The platelet factor 4 (PF4, IU/ml) was $4.7{\pm}1.2$ in control subjects, $18.6{\pm}4.9$ in COPD without pulmonary hypertension subjects and $57.2{\pm}12.7$ in COPD with pulmonary hypertension subjects. The level of COPD subjects was significantly higher than that of control subjects and the level of COPD with pulmonary hypertension subjects was significantly higher than that of COPD without pulmonary hypertension subjects. 3) The beta-thromboglobulin (${\beta}$-TG, IU/ml) was $34.4{\pm}5.8$ in control subjects, $80.4{\pm}18.1$ in COPD without pulmonary hypertension subjects and $93.0{\pm}14.0$ in COPD with pulmonary hypertension subjects. The level of COPD subjects was significantly higher than that of conrtrol subjects and the level of COPD with pulmonary hypertension subjects was tend to increase than that of COPD without pulmonary hypertension subjects. 4) There was no correlation between the clinical parameters and PAR, PF4 and ${\beta}$-TG but there was significant correlation among PAR, PF4 and ${\beta}$-TG. Conclusion: The platelet is activated in chronic obstructive pulmonary disease and the platelet of COPD with pulmonary hypertension is tend to be activated more than that of COPD without pulmonary hypertension. So, activated platelet may involve in the pathogenesis and maintenance of pulmonary hypertension in COPD subjects and modulation of platelet activity that might reduce pulmonary hypertension needs to be determined.

• Korea-Australia Rheology Journal
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• v.20 no.3
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• pp.109-116
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• 2008

The effect of intermolecular aggregation induced by hydrophobic and electrostatic interactions on shear and elongational flow properties of aqueous acrylic thickener solutions is discussed. Complex shear modulus is determined at frequencies up to $10^4$ rad/s employing oscillatory squeeze flow. Extensional flow behavior is characterized using Capillary Break-up Extensional Rheometry. Aqueous solutions of poly(acrylic acid)(PAA)/poly(vinylpyrrolidone-co-vinylimidazole) (PVP-VI) mixtures exhibit unusual rheological properties described here for the first time. Zero-shear viscosity of the mixtures increases with decreasing pH and can exceed that of the pure polymers in solution by more than two orders of magnitude. This is attributed to the formation of complexes induced by electrostatic interactions in the pH range, where both polymers are oppositely charged. PAA/PVP-VI mixtures are compared to the commercial thickener Sterocoll FD (BASF SE), which is a statistical co-polymer including (meth) acrylic acid and ethylacrylate (EA) forming aggregates in solution due to "sticky" contacts among hydrophobic EA-sequences. PAA/PVP-VI complexes are less compact and more deformable than the hydrophobic Sterocoll FD aggregates. Solutions of PAA/PVP-VI exhibit a higher zero-shear viscosity even at lower molecular weight of the aggregates, but are strongly shear-thinning in contrast to the weakly shear-thinning solutions of Sterocoll FD. The higher ratio of characteristic relaxation times in shear and elongation determined for PAA/PVP-VI compared to Sterocoll FD solutions reflects, that the charge-induced complexes provide a much stronger resistance to extensional flow than the aggregates formed by hydrophobic interactions. This is most likely due to a break-up of the latter in extensional flow, while there is no evidence for a break-up of complexes for PAA/PVP-VI mixtures. These flexible aggregates are more suitable for the stabilization of thin filaments in extensional flows.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.343-354
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• 2006

There has been much research efforts trying to integrate mobile IP that has been proposed to guarantee the mobility of mobile nodes on MANET (Mobile Ad Hoc Networks) and wired integrated networks. To support the mobility service of nodes in MIPMANET, this paper proposes MAAM(Mobility Agent Advertisement Mechanism) and AMAAM protocols. In MAAM, the mobility agent of the mobile IP can maintain the information of ad hoc networks by broadcasting advertisement messages periodically. AMAAM(Aggregation based Mobility Agent Advertisement Mechanism) is an enhancement of MAAM for reducing the number of transmission of advertisement messages by aggregating them. The proposed schemes are applied in MIPMANET for agent advertisement mechanism. For the performance evaluation of both protocols, we simulated them by NS2. We evaluate the protocols by ns2 with such performance metrics as packet delivery ratio, transmission throughput, and energy consumption.