• Progress in Medical Physics
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• v.13 no.3
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• pp.114-119
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• 2002

A immobilizing device that is essential for correct lung and lens shielding with homogenous dose distribution in fractionated total body irradiation was developed and it's efficiency was evaluated. The main frame was made of stainless steel bar (5 cm in diameter) to withstand up to 230 cm in height and 100 kg in weight to prevent any injury even in unconsciousness condition. The saddle was designed to adjust the body weight and hight of standing patients. Chest and back supporter were made of 1 cm acryl which could fix the lung block and cassette holder. Leather and sponge pedding were used for head rest to keep patients comfortable. The device was strongly fixed by specially designed bolts on the bottom panel which was made of 1 cm stainless steel and 10 cm thick wooden board. Precise manipulation ($\pm$2 mm) was possible by upper two pulleys and side handles. Average four minutes twenty five seconds were needed for exact setting in fractionated TBI. No significant difference of lung block location on repeated verification films was confirmed and relatively homogeneous dose distribution was measured in rando phantom experiments and patient treatments ($\pm$5%). This immobilizing device was very efficient to keep correct position of patients, which is essential for better result and less complication in fractionated TBI.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.319-334
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• 2006

Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline-hydrochloride(TC-HCI) on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and porous surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml TC-HCI solution for $\frac{1}{2}$ min., 1 min., $1\frac{1}{2}$ min., 2 min., and $2\frac{1}{2}$ min. respectively in the test group and with no treatment in the control group. Then, specimens were processed for scanning electron microscopic observation. 1. Both test and control group showed a few shallow grooves and ridges in pure titanium machined surface implants. There were not significant differences between two groups. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml TC-HCI solution, in general, test specimens were similar to control. 3. In the porous surfaces, the control specimen showed spherical particles of titanium alloy and its surface have a few shallow ridges. The roughness of surfaces conditioned with tetracycline-HCI was lessened and seen crater-like irregular surfaces relative to the application time. In conclusion, pure titanium machined surfaces and SLA surfaces weren't changed irrespective of the application time of tetracycline-HCI solution. But the porous surfaces conditioned with tetracycline-HCI solution began to be slightly changed from 2 min. This results are expected to be applied to the regenerative procedures for peri-implantitis treatment.

• Polymer(Korea)
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• v.36 no.4
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• pp.401-406
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• 2012

For bone regeneration from KUSA-A1 oesteoblast cells (KUSA), chitosan (CS) scaffolds possessing different surface properties, sponge-type (CSS) and nonwoven-type (CSNW), were manufactured. Surface area and pore size of CSNW were larger than those of CSS. On the other hand, the pore volume of CSNW was smaller than that of CSS. Cell attachment evaluation showed CSNW was more adequate then CSS, and this was attributed to the large surface area. For in vivo investigation, KUSA were seeded into CS scaffolds in wells followed by a week of cell culture. Obtained CS scaffolds with KUSA were implanted on the subcutaneous tissue of BALB/C nude mice. After surgery, implanted scaffolds were harvested and assayed by immunological staining. Network stability of CSS was better than that of CSNW, even if CSS scaffolds were destroyed between 4 and 6 weeks. Calcification was observed after 4 and 8 weeks for CSNW and CSS, respectively.

• Polymer(Korea)
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• v.32 no.3
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• pp.199-205
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• 2008

In this study, we fabricated poly (lactide-co-glycolide) (PLGA) scaffold modified with small intestinal submucosa (SIS) as a drug delivery matrix of bioactive molecules. SIS derived from the submucosa layer of porcine intestine has been widely used as biomaterial because of low immune response. PLGA scaffold was prepared by the method of solvent casting/salt leaching. Novel composite scaffolds of SIS/PLGA were manufactured by simple immersion method of PLGA scaffold in SIS solution under vacuum. SEM observation shows that PLGA and SIS/PLGA scaffolds have interconnective and open pores. Especially, SIS/PLGA scaffold showed that micro-sponge of SIS with interconnected pore structures were formed in the pores of PLGA scaffold. In order to assay release profile of proteins, we manufactured FITC conjugated BSA loaded PLGA and SIS/PLGA scaffold. And the release amount was identified by fluorescence intensity using the fluorescence spectrophotometer. The initial burst of BSA containing SIS/PLGA scaffolds was lower than that of PLGA scaffolds resulting in constant release. And release of BSA in SIS/PLGA scaffold was fast and incremental because of the increased content of BSA. In conclusion, we confirmed that penetrated SIS solution prevented the initial burst of BSA and PLGA modified with SIS scaffold is useful as protein carriers with controlled release pattern.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.249-260
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• 1990

Maximal cardiac output and oxygen uptake $(VO_{2max})$ were measured during treadmill exercise for seven top-class marathoners and nine non-athletes using impedance cardiograph developed by one of the authors (DW Kim). Results of this study are summarized as belows. 1) New shoes with sponge and silicon rubber attached to the soles were developed to reduce motion artifact during treadmill exercise. Ensemble everaging techneque with the developed shoes was also used to improve the measurement of stroke volume using impedance cardiography. 2) Maximal cardiac output of the athletes, 14.98 L/min, was significantly higher than that of the non-athletes, 13.46 L/min. As maximal heart rate of the marathoners is lower than that of non-athletes, stroke volume of the former is significantly larger than that of the latter. 3) $VO_{2max}$ of the marathoners, 59.38 ml/kg/min, was higher than that of the non-athletes, 40.22 ml/kg/min. At the anaerobic threshold. $VO_{2max}$ of the former was 62.3% of $VO_{2max}$ and this was significantly higher than that of the non-athletes, 57.2%, This results indicates that the marathoners have higher aerobic capacity than the non-athletes. 4) The marathoners showed larger $VO_2$ than the non-athletes at the same cardiac output, indicating that a-v $O_2$ of the former is higher than that of the latter. 5) Maximal systolic pressure of the marathoners was higher than that of the non-athletes, and so was maximal rate-pressure products. These results indicate that heart oxygen consumption rate $(hVO_2)$ of the marathoner is higher than that of the non-athletes is mainly due to higher stroke volume. And higher oxygen consumption of the marathoners is due to higher stroke volume. And higher oxygen consumption of the marathoners is due to their larger a-v $O_2$. The marathoners show both higher threshold and $VO_{2max}$. Especially, measurement of cardiac output during treadmill exercise by improved impedance cardiography is expected to contribute in study of cardiac function of athletes.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.2
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• pp.63-70
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• 2006

Natural product compounds are the source of numerous therapeutic agents. The marine environment produces natural products from a variety of structural classes exhibiting activity against numerous disease targets including anticancer agents. Among these, pectenotoxin-2 (PTX-2), which was first identified as a cytotoxic entity in marine sponges, which depolymerizes actin filaments, was found to be highly effective and more potent to activate an intrinsic pathway of apoptosis in p53-deficient tumor cells compared to those with functional p53 both in vitro and in vivo. However, the anti-proliferative mechanism of the compound at non-cytotoxic concentrations has not yet been explored. In the current study, we sought to investigate anti-proliferation and apoptosis of PTX-2 against U937 human leukemic cells and its underlying molecular mechanism. Exposure of U937 cells to PTX-2 resulted in growth inhibition and induction of apoptosis in dose- and time-dependent manner as measured by MTT assay, fluorescent microscopy and flow cytometric analysis. The anti-proliferative effect of PTX-2 was associated with a marked increase in the expression of cyclin-dependent kinase p21 (WAF1/CIP1) mRNA which was tumor suppressor p53-independent. The increase in apoptosis was connected with a time-dependent down-regulation of anti-apoptotic Bcl-XL and inhibitor of apoptosis proteins (IAPs) family such as XIAP and cIAP-2. Though additional studies are needed, these findings suggested that PTX-2-induced inhibition of U937 cells was associated with the induction of apoptotic cell death and the results provided important new insights into the possible molecular mechanisms of the anti-cancer activity of PTX-2.

• Membrane Journal
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• v.28 no.6
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• pp.424-431
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• 2018

The gas separation performance of a mixed membrane structure based on a mixture of polyethersulfone (PES) and cobalt tetraphenylporphyrin-benzylimidazole (CoTpp-BIm) as an oxygen carrier was investigated. The CoTpp-BIm mixed PES membrane had an asymmetric structure with a mixture of finger structure and sponge-like structure, and the upper surface was dense. The gas separation performance test was carried out using $94%\;N_2$ gas and $6%\;O_2$ mixed gas. Oxygen and nitrogen permeability coefficients were measured at ${\Delta}P$ ranging from 15 to 228 cmHg and the permeate side of the PES membrane was maintained at vacuum level. The oxygen permeability coefficient of CoTpp-BIm mixed PES membranes increased as supplied pressure was decreased. When the supply pressure was 15 cmHg, the gas permeability ($P_{O_2}$) was 6676 Barrer, the $O_2/N_2$ selectivity (${\alpha}$) was 6.1, and the promoting factor (F) was 2.39. Based on these results, it was confirmed that the addition of CoTpp-BIm to the PES film improved the oxygen separation characteristics.

• Food Engineering Progress
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• v.21 no.1
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• pp.64-71
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• 2017

This study investigated the effects of the mixing ratio of tofu paste and normal corn starch on the characteristics of gluten-free (GF) muffins. Soft wheat flour for wheat flour-based muffins (control) was replaced with the mixture of tofu paste and normal corn starch (NCS). The mixing ratios of tofu paste and NCS were 1:6.4 (S100), 1:5.1 (S80), 1:3.8 (S60), 1:2.6 (S40), 1:1.3 (S20), and 1:0 (S00), based on their total solid contents. GF muffins of S40-S100 developed the porous, sponge-like structure without crumb collapse. The weight and baking loss did not significantly differ in the control and GF muffins. By decreasing NCS in GF muffin batters, the moisture content, firmness, and crumb redness/yellowness of GF muffins increased, while their volume, specific volume, and crumb lightness decreased. Nevertheless, these characteristics (except for firmness) of S100 were much closer to those of the control. In the preference test, however, S60 (possessing lower attributes than S100 and S80) was most favored among GF muffins, and was very similar in all evaluations (except for appearance) to the control. Overall, the mixture of tofu paste and NCS would be a potential material to replace soft wheat flour in muffins.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.109-119
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• 2021

Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. Green roof improves the urban thermal environment and save the cooling energy in buildings. This study presented a green roof combined with a storage system that stores rain-water and supplies water through a wick and evaluated the temperature reduction effect as surface temperature and amount of evapotranspiration. For about a week, the surface temperature using a infrared thermal imager and the evapotranspiration by recording change of module weight were measured at intervals of 30 minutes from sunrise to sunset. The results show that the mean surface temperature of the green roof was 15.4 degrees lower than that of the non-green roof from 12:00 P.M. to 14:00 P.M. There was no significant difference between mean surface temperature of green roof with and without storage system immediately after rain, but more than a week after rain, there was a difference with average of 2.49 degrees and maximum of 4.72 degrees. The difference in daily amount of evapotranspiration was measured to be 1.66 times on average. As drought stress increased over time, the difference in daily amount of evapotranspiration and surface temperature between with/without storage system increased simultaneously. The results of the study show a more excellent cooling effect of green roof combined with the rainwater storage system.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.30-35
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• 2023

The glass bead surface was coated using a TiO₂ sol, after which dry-treated (TB) and calcined (TBc) samples were prepared. Photocatalytic degradation of methylene blue and toluene, as well as characterization of the TiO₂ thin films, were carried out. The TiO₂ thin film of the TB sample had the same shape as the sponge foam, according to FE-SEM, XPS, and FTIR analyses, and contained both amorphous and crystalline TiO₂. On the other hand, crystalline TiO₂ was mainly present in the TiO₂ thin film of the TBc sample, and needle-shaped particles and tiny ones were mixed. The adsorption capacity for methylene blue and the degradation rate of the TBc sample were less than 10 % compared with those of the TB sample, and the adsorption capacity and degradation rate of the TBc sample decreased similarly as the amount of TiO₂ coating increased. The amount of toluene adsorption for the TBc sample (46 mg/g) was smaller than that of the TB sample with the same coating amount, but the degradation rate was similar. In the case of the TB sample, the degradation rate for toluene decreased less than the adsorption capacity as the amount of TiO₂ coating increased. This result is considered to be because, in the non-calcined TB sample, the active site reduction of the crystalline particles occurred less and the specific surface area of the amorphous texture decreased as the amount of TiO₂ coating increased.