• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.183-192
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• 2016

Silver nanomaterials have been intensively applied in consumer products of diverse industrial sectors because of their strong biocidal properties and reported to be hazardous to aquatic organisms once released in the environment. Nanomaterials including sliver, are known to be different in toxicity according to their physicochemical characteristics such as size, shape, length etc. However studies comparing toxicity among silver nanomaterials with different physicochemical characteristics are very limited. Here, toxicities of silver nanomaterials with different size (50, 100, 150 nm), length (10, $20{\mu}m$), shape (wire, sphere), and coating material (polyvinylpyrrolidone, citrate) using OECD test guidelines were evaluated in aquatic species (zebrafish, daphnia, algae) and compared. On a size property, the smaller of silver nanomaterials, the more toxic to tested organisms. Sphered type of silver nanomaterials was less toxic to organisms than wired type, and shorter nanowires were less toxic than longer ones. Meanwhile the toxic effects of materials coated on silver nanomaterials were slightly different in each tested species, but not statistically significant. To the best of our knowledge, it is first investigation to evaluate and compare ecotoxicity of silver nanomaterials having different physicochemical characteristics using same test species and test guidelines. This study can provide valuable information for human and environmental risk assessment of silver nanomaterials and guide material manufacturers to synthesize silver nanomaterials more safely to human and environment.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.247-250
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• 2014

A lipid-soluble extract in ginseng marc was prepared by n-hexane extraction to evaluate its antioxidant and anticancer potential. A hexane extract of ginseng marc (HEGM) possessed a 2,2-diphenyl-1-picryl-hydrazyl free radical scavenging activity which was related to the amount of total phenolics. Also, HEGM showed a potent inhibitory activity on human non-small cell lung cancer (A549, $GI_{50}=34.0{\mu}g/mL$) and colon cancer (SNU-C4, $GI_{50}=45.2{\mu}g/mL$) cells proliferation in vitro in a concentration-dependent manner as did the hexane extract of ginseng with $GI_{50}$ values of $20.0{\mu}g/mL$ in A549 and $37.0{\mu}g/mL$ in SNU-C4. These results imply that HEGM can be utilized as an antioxidant and anticancer substance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1121-1127
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• 2013

This study deals with experimental studies on electromyogram (EMG) measurements and functional electrical stimulation (FES) for the rehabilitation of a shoulder-joint. Based on the structure, motion, and main functions of the musculoskeletal system in a shoulder-joint, the muscles playing a major role for the motion in the sagittal plane were selected for the experiment. First, the surface electromyogram of the main muscles was measured according to the joint angle. The results showed that the change in the surface EMG was linearly proportional to the change in the joint angle. Second, the joint angle was measured during FES at shoulder muscles. The results showed that the joint angle increased as the FES current increased in a certain range of FES. It was confirmed that the willingness of muscles to move could be detected by measuring EMG and that the generation of muscle tension could be assisted by FES for active rehabilitation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.358-369
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• 1997

Hypercholesterolemia is a main risk factor to develop cardiovascular disease, a major cause of death in Korea currently. Dietary factors which shows hypocholesterolemic effect have been reported, which includes plant proteins, unsaturated fatty acids, milk, calcium, flavonoids. Numerous animal and human studies confirmed the pronounced hypocholesterolemic effects of soluble dietary fiber, such as psyllium husk, pectin, sodium alginate, guar gum. Several hypotheses have been proposed to explain the hypocholesterolemic effect of dietary fiber, including binding of bile acids by fiber, interference of lipid absorption and reduced hepatic cholesterol synthesis by propionate, a product of soluble dietary fiber fermentation. Several other hypotheses have been proposed, and these hypotheses are not mutually exclusive.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.91-100
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• 1990

The benzylacycoluridines (BAU and BBAU) are potent and specific inhibitors of uridine phosphorylase (UrdPase). In contrast to the report that benzylacyclouridines potentiated 5-fluoro-2'-deoxyuridine (FdUrd) cytotoxicity against human solid tumor cells (Cancer Res., 44:1852, 1984), continuous exposure of mouse lymphoma L5178Y cells, to FdURd, 5-fluorouridine (FUrd), 5'-deoxy-5-fluorouridine (5'-dFUrd), or 5-fluorouracil (FUra) showed no potentiation of cytotoxicity by benzylacyclouridines. In fact, under the conditions employed, benzylacycoluridines protected the cells from the cytotoxicity of FdUrd, FUrd, or 5'-dFUrd, but not FUra in a dose dependent manner. Intraperitoneal coadministration of BAU or BBAU and a 5-fluorinated pyrimidine (i.e., FdUrd, FUrd, or FUra), to mice bearing L5178Y cells also did not significantly increase the life span compared to those treated with the antimetabolites alone. Anabolism of these nucleosides through the sequential action of UrdPase and orotate phosphoribosyltransferase (OPRTase), inhibition of nucleoside transport by benzylacyclouridines, or both could be responsible for the ineffectiveness of UrdPase inhibitors to potentiate the antineoplastic activity of fluoropvrimidines in L5178Y cells.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.539-544
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• 1989

Campylobacter jejuni, bacterial agent causing human diarrhea, were studied for their disinfection effects with chlorine and monochloramine. The cells treated with the chemical agents were observed by scanning electron microscopy to know their morphological and structural changes. The proteins and DNA in the chemical-treated cells were also examined by gel electrophoresis for structural changes. When C. jejuni were chlorinated at concentrations of 0.5 and 1.0 mg/l for 15 minutes, the organisms were disinfected by 4 and 6 log, respectively. Those disinfection effects were higher at acidic pH, while lowered at neutral and alkaline values of pH. The effects of monochloramine were lower than those of chlorine at the game concentration for the same period of reaction time. The shapes of C. jejuni cells treated with the agents appeared to be deformed from spiral rod into spherical forms, showing some destruction in surface structure of the cells. Some of the proteins and DNA of the chlorinated cells did not appear in the gel electrophoresis when the chlorination was at concentration of 10 mg/l or higher.

• Food Industry And Nutrition
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• v.12 no.2
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• pp.51-57
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• 2007

한국산 복령과 후박의 이용성 확대를 위하여 각각 추출물의 ABTS와 DPPH라디칼의 소거능, 환원력의 항산화능 효과 및 인체암 세포주의 항암활성에 대하여 조사하였다. 복령과 후박을 버섯균사체로 발효시킨 한약 추출액의 항산화활성(ABTS와 DPPH 라디칼소거, 환원력)은 시료 추출물의 농도가 증가할수록 비례적으로 증가하였으며, DPPH 라디칼 소거활성은 ABTS보다 비교적 높게 나타났고, 원료후박 추출물($21.16{\sim}24.68%$)은 원료복령 추출물($45.46{\sim}49.63%$)에 비하여 약 2배 이상 높았다. 복령 시료 추출물의 농도별에 따른 환원력은 원료 복령($0.55{\sim}0.63$)에 비하여 동충하초, 팽이버섯 및 큰 느타리 균사체로 발효시킨 시료($0.50{\sim}0.62$)의 흡광도로 서로 비슷한 증가를 나타내었고, 후박 시료 추출물의 농도별에 따른 환원력은 원료 후박 추출물($0.98{\sim}1.06$)이 3가지의 버섯 균사체 발효후박 추출물($0.76{\sim}1.01$)에 비하여 약간 높았다. 자궁경부암세포(HeLa)와 대장암세포(HT-29)는 원료복령과 후박의 추출물이 각각의 발효한약에 비하여 저해활성이 높았다. 간암세포(HepG2)는 $200{\mu}g/assay$ 농도에서 팽이버섯 균사체 발효복령의 추출물이 가장 높았는데, 원료복령과 동충하초 및 큰 느타리에 비하여 각각 1.79, 1.35, 1.03배 높은 저해활성을 나타내었다. 그리고 팽이버섯과 동충하초 균사체를 배양한 발효후박에서 각각 $11.39{\sim}53.92%$, $10.71{\sim}50.21%$ 범위였으며, 원료후박에 비하여 $200{\mu}g/assay$ 농도에서 각각 2.21배, 2.05배 높은 저해활성을 나타내었다. 유방암세포(MCF-7)는 발효복령 추출물의 저해활성이 팽이버섯 균사체($58.35{\sim}72.87%$)에서 가장 높았으며, 큰 느타리버섯($61.04{\sim}67.66%$)과 동충하초($39.74{\sim}66.40%$) 및 원료복령($50.32{\sim}69.24%$)은 서로 비슷하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.726-731
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• 2000

This study was performed to evaluate the antitumor activities of water and ethanol (EtOH) extract of Salvia miltiorrhiza in vitro and in vivo. The proliferation of the human hepatoma (HepG2), rectum cancer (HRT-18) and colon cancer (HT-29) cells was inhibited by administration of extracts in a dose-dependent manner. Particularly, EtOH extract inhibited proliferation of the cells more effectively than water extract did. The morphology of cells induced by EtOH extract was characterized by reduction of cell size and deformatin. Oral administration of the EtOH extract (3 mg/head) to tumor-bearing mice inhibited the tumor (sarcoma-180) growth by 35% and prolonged their survival rate by 61%. The EtOH extract was shown to be nontoxic at 37.5% mg/head/day on the acute toxicity test. These studies suggest that the EtOH extract of Salvia miltiorrhiza may have antitumor activity in vitro and in vivo.

• Journal of Biomedical Engineering Research
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• v.23 no.6
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• pp.419-430
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• 2002

In this paper. we propose an efficient method for implementing hi-directional pixel-based focusing(BiPBF) based on a sparse array imaging technique. The proposed method can improve spatial resolution and frame rate of ultrasound imaging with reduced hardware complexity by synthesizing transmit apertures with a small number of sparsely distributed subapertures. As the distance between adjacent subapertures increases, however. the image resolution tends to decrease due to the elevation of grating lobes. Such grating lobes can be eliminated in conventional synthetic aperture imaging techniques. On the contrary, grating lobes arisen from employing sparse synthetic transmit apertures can not be eliminated, which has been shown analytically in this paper. We also propose the condition and method for suppressing the grating lobes below -40dB, which is generally required in practical imaging. by placing the transmit focal depth at a near depth and properly selecting the subaperture distance in Proportion to receive aperture size. The results of both the Phantom and in vivo experiments show that the proposed method implements two-wav dynamic focusing using a smaller number of subapertures, resulting in reduced system complexity and increased frame rate.

• Fire Science and Engineering
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• v.26 no.3
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• pp.40-48
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• 2012

Fire patterns have been used to determine the origin and cause of fires in every setting imaginable. However, it is very difficult to identify fire patterns and causes from the fire-damaged remains of a devastated structure. If someone was killed by the fire, it is possible to identify fire patterns by analyzing the Hb-CO concentration in charred bodies of deceased as well as the pace of the fire. For example, a low level of Hb-CO concentration in the charred bodies indicate a rapid fire with accelerants and the death was caused by severe heat and thick toxic fumes. However, a high level of Hb-CO concentration in the charred bodies demonstrates that the fire was slow and/or there was a flameless form of combustion. Thus, it is possible to identify fire patterns through analyzing the level of Hb-CO concentration on the dead from the fire. In this study, the Hb-CO concentration in the charred bodies was from 3 % at the case of gas burning oneself to death to 93 % at the death caused by smoldering fire.