• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.31-37
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• 2017

Recently, there has been substantial interest in flexible and wearable devices whose properties and performances are close to conventional devices on hard substrates. Despite the advancement on flexible devices with organic semiconductors or carbon nanotube films, their performances are limited by the carrier scattering at the molecular to molecular or nanotube-to-nanotube junctions. Here in this study, we demonstrate on the vertical semiconductor crystal array embedded in flexible polymer matrix. Such structures can relieve the strain effectively, thereby accommodating large flexural deformation. To achieve such structure, we first established a low-temperature solution-phase synthesis of single crystalline 3D architectures consisting of epitaxially grown ZnO constituent crystals by position and growth direction controlled growth strategy. The ZnO vertical crystal array was integrated into a piece of polydimethylsiloxane (PDMS) substrate, which was then mechanically detached from the hard substrate to achieve the freestanding ZnO-polymer composite. In addition, the characteristics of transferred ZnO were confirmed by additional structural and photoluminescent measurements. The ZnO vertical crystal array embedded in PDMS was further employed as pressure sensor that exhibited an active response to the external pressure, by piezoelectric effect of ZnO crystal.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.161-166
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• 2016

This study was designed to investigate whether or not onion peel extract can lower blood lipid levels in rats exposed to cigarette smoke (CS) extract with a high-fat diet. Initially, male Sprague-Dawley rats were housed individually in a stainless steel, wire-bottomed cage with free access to AIN-93G diet. Rats were weight-matched and assigned to the following five groups: 1) control rats (CT) fed standard AIN-93G diet alone, 2) control rats exposed to CS extract (CT+CS), 3) high-fat group (HF) fed standard AIN-93 diet supplemented with 3% lard and 0.2% cholesterol, 4) high-fat group exposed to CS extract (HF+CS) fed standard AIN-93 diet supplemented with 3% lard and 0.2% cholesterol plus CS extract, and 5) high-fat plus onion peel (OP) extract group exposed to CS extract (HF+CS+OP) fed standard AIN-93 diet supplemented with 3% lard, 0.2% cholesterol, and onion peel extract (20 mg/17 g diet) plus CS extract. Using this feeding protocol, all animals completely consumed their respective diets throughout the 6 week duration. Blood was collected via the orbital sinus at weeks 0, 3, and 6, following overnight food deprivation. OP extract feeding resulted in significant reductions in blood triglyceride, total cholesterol, and non-HDL-cholesterol. Further, serum activities of aspartate transaminase and alanine transaminase were significantly reduced by OP extract at 6 weeks. These results provide clear evidence that onion peel extract has a profound inhibitory effect on blood lipids in rats exposed to CS extract. These findings suggest that OP extract can be used as an effective means in alleviating the serum lipid concentration after CS exposure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.104-108
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• 2002

Numerous studies have suggested the involvement of oxidative processes in the pathogenesis of atherosclerosis and especially of oxidized low density lipoproteins (LDL). We studied the effect of Korean wheat on the oxidizability of LDL and the development of experimental atherosclerosis in rabbits on cholesterol diet. For the approach of the aim, antioxidative activity of wheat extracts against oxidation of LDL was investigated. The antiatherogenic effect of wheat was studied against Newzealand whithe (NZW) rabbits fed containing the wheat powder for 12 weeks. PBS extracts of Korean and imported wheats decreased LDL oxidation induced by copper ion by 62.3%, 52.6% respectively in comparison with control. Liver thiobarbituric acid reactive substance (TBARS ) levels of rabbits were significantly lowered in Korean wheat fed group (0.397$\pm$ 0.029 nmol MDA/mg protein, p<0.05) compared to control (0.496$\pm$0.021 nmol MDA/mg protein) and imported wheat group (0.478$\pm$0.019 nmol MDA/mg protein). TBARS levels of kidney showed no significant difference among treatment groups. The aorta of cholesterol-fed rabbits showed typical atherosclerotic lesions when compared with the controls, but the microscopic differences between groups was not clear. The present study suggests that Korean wheat may have higher antioxidative capacity than imported wheat and have more beneficial effects for the treatment of disease by inhibiting the oxidation of LDL.

• Journal of Environmental Policy
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• v.12 no.1
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• pp.75-100
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• 2013

Health damages such as pneumoconiosis and kidney damage, caused by environmental hazardous factors are being reported in health impact assessment conducted on environmentally vulnerable areas, including cement factories and refineries. Current legal system for relieving the environmental victims is not effective enough because the environmental health act does not specify the environmental hazardous factors to be considered for the relief. The aim of this study is to examine the problems of the existing system by making empirical analysis on health damages and afflicted people as well as on cases when afflicted people were able to be covered by remedy system. The results show that, insufficiencies of the relief system are due to the following reasons: First, current Environmental Health Act does not act well as a remedy system. Second, due to its unique nature of environmental health damage, it is hard to identify and prove the cause of health damage and unlawful actions of violators in the process of environmental dispute conciliation and lawsuits against polluters. This paper suggests following solutions on above mentioned problems. First, in defining the range and definition of environmental diseases, negative system should be used alongside with the current positive system. Second, we suggest adding the nature of public law to relief system, in order to ease the legal burden of proof. Third, in case when it is hard to identify the polluters and one cannot expect reliefs for their damage, it is possible to elevate the effectiveness of the relief measure by expanding scope of the search for possible environmental hazardous factors that caused the health damage. It is urgent to improve the relief system so as to secure the environmental rights of Koreans.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.222-227
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• 2017

Red ginseng prepared from fresh 6-year-old ginseng treated with colloidal gold nanoparticles was extracted using hot water to evaluate its total phenolic and flavonoid contents, antioxidant capacity, and neuroprotective effects. Water extract of red ginseng treated with gold nanoparticles (WERGGN) had total phenolic and total flavonoid contents of 212.2 mg gallic acid equivalents/$^{\circ}Bx$ and 3.5 mg catechin equivalents/$^{\circ}Bx$, respectively. The antioxidant capacities of WERGGN measured using ABTS, DPPH, and ORAC assays were 272.3, 141.2, and 868.4 mg vitamin C equivalents/$^{\circ}Bx$, respectively. The WERGGN showed protective effects on the viability of neuron-like PC-12 cells against oxidative stress induced by hydrogen peroxide in a dose-dependent manner, partly because of a reduction in intracellular oxidative stress. Acetylcholinesterase and butyrylcholinesterase, which degrade the neurotransmitter acetylcholine to terminate neurotransmission, were inhibited by treatment with WERGGN. These results suggest that WERGGN is useful as a functional material to decrease oxidative stress and neuronal damage.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.3
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• pp.183-190
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• 2000

The purpose of this study is to evaluate the magnetic property change of the nuclear reactor vessel steel irradiated by fast neutrons using $M{\ddot{o}}ssbauer$ spectroscopy, and the effects of the defects produced by neutron irradiation on the changes using X-ray diffraction. The specimens, fabricated with the dimension of $23mm{\times}18mm{\times}70{\mu}m$, were irradiated by neutron fluence from $10^{12}n/cm^2\;to\;10^{18}n/cm^2$ at 343K. Throughout the experiments, it is understood that (1) the X-ray diffraction measurement shows that the change of crystal nature is started at the irradiation of $10^{16}n/cm^2$ and a crystal structure has been severely damaged at the irradiation over $10^{17}n/cm^2$, (2) the analysis of the $M{\ddot{o}}ssbauer$ spectra has shown that magnetic transition phenomena occur at the irradiation over $10^{17}n/cm^2$ and (3) both methods can be utilized as nondestructive test methods for the embrittlement evaluation of materials irradiated by fast neutrons.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.83-91
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• 2012

Quorum sensing (QS) is a cell-to-cell communication system, which is used by many bacteria to regulate diverse gene expression in response to changes in population density. Bacteria recognize the differences in cell density by sensing the concentration of signal molecules such as N-acyl-homoserine lactones (AHL) and autoinducer-2 (AI-2). In particular, QS plays a key role in biofilm formation, which is a specific bacterial group behavior. Biofilms are dense aggregates of packed microbial communities that grow on surfaces, and are embedded in a self-produced matrix of extracellular polymeric substances (EPS). QS regulates biofilm dispersal as well as the production of EPS. In some bacteria, biofilm formations are regulated by c-di-GMP-mediated signaling as well as QS, thus the two signaling systems are mutually connected. Biofilms are one of the major virulence factors in pathogenic bacteria. In addition, they cause numerous problems in industrial fields, such as the biofouling of pipes, tanks and membrane bioreactors (MBR). Therefore, the interference of QS, referred to as quorum quenching (QQ) has received a great deal of attention. To inhibit biofilm formation, several strategies to disrupt bacterial QS have been reported, and many enzymes which can degrade or modify the signal molecule AHL have been studied. QQ enzymes, such as AHL-lactonase, AHL-acylase, and oxidoreductases may offer great potential for the effective control of biofilm formation and membrane biofouling in the future. This review describes the process of bacterial QS, biofilm formation, and the close relationship between them. Finally, QQ enzymes and their applications for the reduction of biofouling are also discussed.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.3 no.1
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• pp.21-25
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• 2010

Purpose: To evaluate efficacy of ultrasound guided prolotherapy in patients with persistant symptoms after rotator cuff repair. Materials and Methods: Between January and December of 2008, 90 patients who had persistant pain and shoulder adhesion 4 weeks after rotator cuff repair were treated with ultrasound guided prolotherapy. The mean age was 55.2 years. Visual analogue scale (VAS) and range of motion (ROM) before and after the procedure, complications related to the procedure were analyzed. Results: The average VAS score at 4 weeks follow up decreased to $2.5{\pm}2.304$ from $6.3{\pm}1.25$ before prolotherapy and forward flexion range at 4 weeks follow up increased to $143{\pm}26.63$ from $106{\pm}21.64.$ Four weeks after the ultrasound guided prolotherapy, 74 cases(82%) reported of improved pain and ROM, 13 cases(14%) reported of improvement after 2~5 days of the procedure and 3 cases(4%) had no improved in pain and ROM. No complications were encountered. Conclusion: The authors believe that ultrasound guided prolotherapy in repaired rotator cuff tear patients theoretically increased possibilities of healing and with relieving the pain of the patients results in increased possibility of rehabilitation effect.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.4
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• pp.327-338
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• 2012

Liquiritigenin and isoliquiritigenin are the major flavonoids present in licorice. These flavonoid compounds were prepared by submerged culture of Grifola frondosa (G. frondosa) HB0071 mycelia producing ${\beta}$-glucosidase in the aqueous extract of licorice. The contents of liquiritigenin and isoliquiritigenin were increased during the fermentation. This fungus produced a high ${\beta}$-glucosidase (activity of 91.5 mU/mL), thereby achieving high amounts of liquiritigenin and isoliquiritigenin ($568.5{\mu}g/mL$ and $89.6{\mu}g/mL$), respectively at 96 h. A reversed- phase high-performance liquid chromatography method was established for simultaneous determination of liquiritigenin and isoliquiritigenin in fermented licorice extract (FLEx). The anti-inflammatory activities were investigated by licorice extract (LEx) before and after fermentation with G. frondosa HB0071. The treatment of UVB-irradiated HaCaT keratinocytes with FLEx resulted in a dose-dependent decrease in the expression level of cyclooxygenase-2 (COX-2) mRNA. Furthermore, FLEx dose-dependently decreased mRNA of the pro-inflammatory cytokines of IL-$1{\beta}$ and IL-6 in UVB-irradiated HaCaT cells. These results suggest that FLEx may mitigate the effects of skin inflammation by reducing UVB-induced adverse skin reactions.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.19-28
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• 2011

This study developed a solar radiation reflection pavement, so called a cool pavement, to lessen the urban heat island effect by coating a pavement surface with acrylic resins mixed with light-colored pigments. From a laboratory test, simulating solar heating process in pavements, the cool pavement reduced more than $12^{\circ}C$ of pavement temperature at $60^{\circ}C$ compared to a control porous pavement. With the increase of the mixing ratio of the pigments to acrylic resins, the temperature reduction effect increased, but its workability became worse due to higher viscosity. As a result, an appropriate mixing ratio was determined as 15%. The cool pavement had better durability than the control pavement: One quarter of Catabro loss and twofold dynamic stability. Its adhesion was also higher enough not to be debonded under traffic loading. In-situ noise and friction tests conducted in two field sites showed that the cool pavement reduced its noise level by 3.7dB in average and increased its friction level by 30% compared to the control pavement. The permeability of the cool pavement was little lower than the control pavement, but higher enough to satisfy the minimum requirement for porous pavements.