• Analytical Science and Technology
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• v.16 no.3
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• pp.191-197
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• 2003

Two methods, IDMS (Isotope Dilution Mass Spectrometry) and controlled potential coulometry are compared by the determination of Pu for the NBL, CRM No.122, $PuO_2$. The recovery of Pu was found to be $1.002176{\pm}0.000452$ within the relative standard deviation of 0.045% (95% conf. level) although a small size of sample ($0.9{\mu}g$-Pu) was used in IDMS. The recovery using controlled potential coulometry were obtained in the range of 0.9923~0.9960. The analytical results of IDMS and controlled potential coulometry were good agreement within 0.6~1%. Base on these experiment results, The plutonium in HANARO irradiated fuel rod that separated portion of top, middle, and bottom were determined. The measured values of Pu are 1.155 mg, 2.483 mg and 1.920 mg in one gram of sample(fuel+clad), respectively.

• Journal of Adhesion and Interface
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• v.13 no.4
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• pp.163-170
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• 2012

Although ${\beta}$-cyclodextrin (${\beta}$-CD) has been used as medicine, agrichemical, food, cosmetic, antioxidant, anti-volatile agent, anti-hygroscopic agent, fading-protecting agent, and emulsifier due to its ability to form inclusion complex by enclosing another molecule (guest molecule), it has been restricted in practical application because of its low solubility in water and organic solvent. In this study, ${\beta}$-CD derivative as a new polyol with inclusion characteristics against Bisphenol A and cyclopropane, foaming agent for polyurethane (PU), and with improved solubility was synthesized, characterized and used to formulate rigid PU foam with better thermal conductivity and compressive strength compared to that from commercial polyols.

• Journal of Fashion Business
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• v.23 no.2
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• pp.1-17
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• 2019

The objective of this study was to investigate electrical conductivity of fabrics from polyester (PET) and Nylon (N) containing polyurethane (PU), with silver paste patterns screen-stenciled in three directions. The PET/PU and N/PU fabrics knitted or woven were uniaxially strain-recovered up to 22.5% in three times when each change in electrical resistance was simultaneously measured. This study established four variables that complexly affected electrical conductivity of these specimens; fabric structures, components, cover factors, and the percolation of silver particles. The woven or knitted fabric structures did not distinctively cause the changes in electrical resistance, however, the woven fabrics with the diagonal patterns showed their relatively high electrical resistance. The PET/PU fabrics with increasing the PET proportion generally presented the opposite propensity to its electrical conductivity. The changes in electric resistance of the PET/PU 85/15 2/1 twill and double plain fabrics instantaneously responded to the rate of elongation. The PET/PU group exhibited a reverse correlation between its cover factor and electrical resistivity. The highest electrical conductivity of the PET/PU 95/5 interlock fabric, with very few fluctuations, was attributed to the deep percolation of the silver particles that bridged the gaps between one loop and another. On the other hand, the occurrence of the silver cracks along with the elongated direction led to the immeasurably high change in electrical resistance as the strain increased.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.63-72
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• 2003

Although a variety of synthetic vascular grafts are available in modern vascular surgery, no ideal prosthesis ha,4 yet been developed. Small-caliber vascular grafts with low flow, as used in the lower extremity, continue to become thrombosed at unacceptable rates. We have developed and evaluated the new antithrombogenic blood contacting surfaces in canine model. Material and Method: Two now antithrombogenic blood contacting surfaces(Polyvinylalcohol -Polyurethane(PVA-PU) blend and natural Graphite-polyurethane(G-PU) blend) have been developed and evaluated in canine model, using vascular grafts and patches. The luminal surfaces of the test vascular grafts(5 mm ID) were fabricated by dipping a glass rod in PVA-PU blend solution(50 % PVA) using phase separation method. Mongrel dogs of either sex weighing 18-22 kg were anesthetized by endotracheal intubation using halothane and their lungs were ventilated with a volume-cycled ventilator, Maintenance anesthesia with 0.5-1.0% halothane and supplemental oxygen was used. Two pairs were used for comparison in the bilateral femoral arteries for both vascular grafts(PVA-PU vs. PU) and vascular patches(G-PU vs. PU). Bilateral groin incisions were made and the arteries were exposed and clamped. After an excision of 1 cm of the artery between clamps, a grail of 2.5 cm in length was implanted end-to-end using 6-0 polypropylene suture. The vascular patch was implanted as a form of on-lay patch. Animals were sacrificed at 1, 2, 4, 6, 8 and 16 weeks for vascular grafts and 1, 2. 4 and 6 weeks for vascular patches. Result The vascular grafts of PVA-PU blends showed patent lumina in the 2 and 16 weeks animals, while those of PU showed a patent lumen in 2 weeks animal. PVA-PU graft of 16 weeks showed a fairly clean luminal surface. A light microscopic finding of this graft demonstrated good tissue infiltration through porosity, The animals with vascular patches showed patent arteries in both groups except 2 weeks animal. Scanning electron microscopy of the luminal surfaces of G-PU patches in 4 and 6 weeks animals showed endothelial cell covering with microvilli. PU patches showed qualitatively less endothelial cell covering. Conclusion: In conclusion, PVA-PU and G-PU blends can be a promising blood contacting surfaces for application in a synthetic vascualr graft. However, further animal study is needed to determine the real long-term effects of these methods of surface modifications.

• The Journal of Internal Korean Medicine
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• v.35 no.1
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• pp.24-36
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• 2014

Objectives : This study was performed to evaluate the effects of moxibustion on cerebral blood flow, peripheral blood flow and blood pressure. Methods : We designed a randomized, cross-over study that included 20 healthy, male volunteers who were randomly assigned to one of two groups (the moxibustion group or the control group). The initial trial was followed by a washout period of one week before the groups were switched and the trial repeated. The cerebral blood flow and peripheral blood flow of the volunteers in both groups were measured by mean velocity (Vm), peak systolic velocity (Vs), pulsatility index (PI), perfusion units (PU) and mean blood pressure (BP) before the intervention (baseline), 30 minutes after the intervention, and again 60 minutes after the intervention. Results : 1. The Vm increased significantly in the moxibustion group. The Vs also constantly increased in moxibustion group, but there was no significant difference. 2. The PI decreased significantly in the control group at 0-30 minutes and in the moxibustion group at 30-60 minutes. 3. The PU constantly decreased in moxibustion group. In control group, the PU decreased at 30 minutes and increased slightly at 60 minutes. 4. The mean blood pressure did not show any significant difference between the two groups. Conclusions : This study shows that moxibustion at CV12 increased the cerebral blood flow. Based on this result, we can suggest that moxibustion at CV12 might be helpful in improving the functional recovery of stroke patients. However, further research needs to be conducted on a larger numbers of subjects in order to confirm these effects.

• The Journal of Internal Korean Medicine
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• v.35 no.2
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• pp.175-183
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• 2014

Objectives : We tried to uncover the anti-lipogenic effect and underlying mechanism of Laminaria japonica on an experimental cellular model of non-alcoholic fatty liver disease. Methods : Ethanol extract of Laminaria japonica (LJ) was prepared. Intracellular lipid content of palmitate-treated HepG2 cells was evaluated with or without LJ treatment. We measured the effects of LJ on liver X receptor ${\alpha}$ ($LXR{\alpha}$) and sterol regulatory element-binding transcription factor-1c (SREBP-1c) expression, transcription level of lipogenic genes, including acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), and nuclear factor erythroid 2-related factor 2 (Nrf2) activation in HepG2 cells. Results : LJ markedly attenuated palmitate-induced intracellular lipid accumulation in HepG2 cells. LJ suppressed $LXR{\alpha}$-dependent SREBP-1c activation, and SREBP-1c mediated induction of ACC, FAS, and SCD-1. Furthermore, LJ activated Nrf2, which plays an important cytoprotective role in non-alcoholic fatty liver disease. Conclusions : Our study suggests that LJ has the potential to alleviate hepatic lipid accumulation, and this effect was mediated by inhibiting the $LXR{\alpha}$-SREBP-1c pathway that leads to hepatic steatosis. In addition, the anti-lipogenic potential may, at least in part, be associated with activation of Nrf2.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.102-109
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• 2011

Antioxidant and antibacterial activities of Phlomis umbrosa Turcz. (PU) ethanol extracts were investigated in vitro. Total polyphenols, flavonoids and FRAP values of PU extracts were $57.32{\pm}2.30{\mu}g$/mg, $21.44{\pm}2.52{\mu}g$/mg and 0.26 mmol $Fe^{2+}$/g, respectively. The PU extracts also showed strong DPPH scavenging activity and antibacterial effects against Staphylococcus aureus. In addition, the DPPH scavenging effect of the seasoning sauces was increased by the addition of PU extracts. This study was also conducted to evaluate the quality characteristics of seasoned pork treated with PU extracts during storage at $4^{\circ}C$ for 21 days. Seasoned pork was produced containing 0, 0.5, and 1% PU extracts and 0.1% BHA. The total bacteria and TBARS values of seasoned pork added with PU were decreased compared to the control, whereas coliform bacteria were not detected after longer storage periods. With regards to sensory evaluation, seasoned pork treated with 0.5% PU had higher juiciness, flavor and overall acceptability compared to seasoned fork. These results suggest the possibility of manufacturing seasoned pork with PU extracts for the improvement of shelf-life and quality.

• Journal of Radiation Protection and Research
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• v.44 no.3
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• pp.118-126
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• 2019

Background: Government conducts environmental radioactivity surveillance for verification purpose around nuclear facilities based on the Nuclear Safety Law and issues a surveillance report every year. This study aims to evaluate the short and the long-term fluctuation of radionuclides detected above MDC and their origins using concentration ratios between these radionuclides. Materials and Methods: Sample media for verification surveillance are air, rainwater, groundwater, soil, and milk for terrestrial samples, and seawater, marine sediment, fish, and seaweed for marine samples. Gamma-emitting radionuclides including $^{137}Cs$, $^{90}Sr$, Pu, $^3H$, and $^{14}C$ are evaluated in these samples. Results and Discussion: According to the result of the environmental radioactivity verification surveillance in the vicinity of nuclear power facilities in 2017, the anthropogenic radionuclides were not detected in most of the environmental samples except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples. Radioactivity concentration ratios between the anthropogenic radionuclides ($^{137}Cs/^{90}Sr$, $^{137}Cs/^{239+240}Pu$, $^{90}Sr/^{239+240}Pu$) were similar to those reported in the environmental samples, which were affected by the global fallout of the past nuclear weapon test, and Pu atomic ratios ($^{240}Pu/^{239}Pu$) in the terrestrial sample and marine sample showed significant differences due to the different input pathway and the Pu source. Radioactive iodine ($^{131}I$) was detected at the range of < $5.6-190mBq{\cdot}kg-fresh^{-1}$ in the gulfweed and sea trumpet collected from the area of Kori and Wolsong intake and discharge. A high level of $^3H$ was observed in the air (Sangbong: $0.688{\pm}0.841Bq{\cdot}m^{-3}$) and the precipitation (Meteorology Post: $199{\pm}126Bq{\cdot}L^{-1}$) samples of the Wolsong nuclear power plant (NPP). $^3H$ concentration in the precipitation and pine needle samples showed typical variation pattern with the distance and the wind direction from the stack due to the gaseous release of $^3H$ in Wolsong NPP. Conclusion: Except for the detection of a trace level of $^{137}Cs$, $^{90}Sr$, Pu, and $^{131}I$ in some samples, anthropogenic radionuclides were below MDC in most of the environmental samples. Overall, no unusual radionuclides and abnormal concentration were detected in the 2017's surveillance result for verification. This research will be available in the assessment of environment around nuclear facilities in the event of radioactive material release.

• Nuclear Engineering and Technology
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• v.20 no.3
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• pp.165-169
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• 1988

As a part of tandem fuel cycle feasibility study, the residual U and Pu nuclide contents of PWR spent fuels are computed using ORICEN2 code for each Korea Nuclear Unit and batch to investigate the potential of utilizing them as CANDU fuels. The annual and accumulated discharged amounts of U and Pu nuclides are computed for the PWRs from KNU 1 through KNU 10. The results of computation show that the spent fuels having 0.7-0.8 w/o U-235 are dominant and considerable amounts of fissile Pu are produced. The enrichment of U-235 is less than the expected 0.8-0.9 w/o U-235 since the burnups offered by KEPCO are higher than those of other PWRs.

• Fibers and Polymers
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• v.5 no.3
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• pp.239-244
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• 2004

Solution-cast films of polymethylmethacrylate (PMMA) and polyurethane (PU) containing polymeric styryl dye up to 5 % by weight were prepared to investigate their acid-sensitivity and mechanical and thermal properties. Original red samples due to styryl dye turned out yellow very rapidly as they were exposed to acid vapor of hydrochloric acid or p-toluenesulfonic acid. According to UV/VIS spectroscopic measurements, characteristic peak intensities near 430 nm and 520 nm increased or decreased relatively with exposed amounts of acid, respectively. Both PMMA and PU samples showed uniform color distribution due to a good miscibility between polymer and dye which can be evidenced by measurements of glass transition temperature. No significant difference in acid-sensitivity was found between PU and PMMA except relative absorbance. However, dependence of their mechanical properties on dye content was somewhat different with PU or PMMA. In case of PMMA, modulus and breaking stress increased up to about 50 % with increasing dye content, whereas those of PU samples showed only slight increase. It was ascribed to whether the matrix polymer was in the glassy or rubbery state.