• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.19-24
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• 1995

The effect of several inhibitors such as ascorbic acid on the lipoxygenase in soybeans known to catalyze reaction resulting in racid off-flavors was examined in the soybean homogenates by the oxygen electrode method. Among 8 compounds added at homogenizing process, 10 mM ascorbic acid inhibited lipoxygenase-1 and lipoxygenase-2/3 activities to 41.7 and 49.8%, respectively. Inactivation of lipoxygenase-2/3 was highly accelerated by homogenization for 15 min at room temperature, so the activity was inhibited 70.8% comparing with the homogenization of 3 min. When soybean homogenates with 10 mM ascorbic acid was stored at $25^{\circ}C$ for 72 hrs, lipoxygenase-2/3 activities lowered to 52.8% whereas L-1 activities lowered to 15.8%. Since it is reported that lipoxygenase-2 is responsible for the off-flavor of soybean products, the inhibitory effect of ascorbic acid among several inhibitors investigated might be useful in soybean processing.

• Journal of the Korean Geotechnical Society
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• v.31 no.3
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• pp.51-62
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• 2015

Shear behavior obtained by direct shear tests is dependent on shear box and boundary condition. The objective of this study is to analyze problems of conventional direct shear test (type-A) and provide the reliable results by developing type-C direct shear apparatus. Experimental tests are carried out for Ulleung sand by using type-A and -C direct shear devices. The soil specimens, which are prepared at the relative density of 60%, and are applied to vertical confining stresses of 50, 100, 200, 300, and 400 kPa, are sheared at a constant shear strain rate of 0.5 mm/min. By comparing the results obtained by type-A and -C direct shear apparatus under constant normal load (CNL) condition, the performance of new one is verified. In addition, two constrained conditions including constant normal load (CNL) and constant pressure (CP) are applied to type-C one. Experimental results show that type-A direct shear apparatus has some problems such as rotating of loading plate and upper shear box, and the frictional forces between soil and inner wall of upper shear box. Thus, the shear strengths obtained by type-A device are overestimated or underestimated depending on shear box and boundary condition. On the other hand, type-C device produces clear and consistent test results regardless of constrained conditions. This study represents that type-C direct shear apparatus not only can solve the problems of type-A direct shear apparatus but provide the reliable results.

• KSBB Journal
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• v.29 no.1
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• pp.58-66
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• 2014

Demand for in vitro pharmacological evaluation and toxicity test using human hepatocytes has been increasing. In USA and Europe, human hepatocytes obtained from donated whole liver unsuitable for transplantation were distributed to researchers and deposited in cell bank facility as cryopreserved vial. In Korea, however, incidence of transplantation- inappropriate whole liver has been quite low and the whole livers almost have so severe liver disease such as fatty or fibrotic liver that cannot meet the demand. In this study we aimed to isolate human hepatocytes from liver resection surgery-originated partial liver, and assure the isolated human hepatocytes and its cryopreserved hepatocytes to be qualified for the in vitro pharmacological evaluation and drug toxicity tests. We compared those with commercially available human hepatocyte, BD $GenTest^{TM}$ by cell morphology, hepatic gene expression, urea synthesis, albumin secretion, ammonia removal, and cytochrome P450 induction activities. Changes in hepatotoxic gene expression after cryopreservation are evaluated with a typical hepatotoxic drug, acetaminophen. Consequently, the fresh hepatocytes from the partial liver and its cryopreserved hepatocytes expressed their intrinsic hepatic functions well and showed equal hepatotoxicity gene expression trend regardless to cryopreservation. Therefore, liver resection surgery-originated partial liver can be used as a useful source of human hepatocytes for various pharmacological and hepatotoxicity test.

• Journal of the Korean GEO-environmental Society
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• v.14 no.1
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• pp.5-13
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• 2013

Soils around a pile are highly constrained when the vertical load is applied to the pile. However, the conventional direct shear test cannot evaluate the shear strength of the soils under the normal confinement condition. The goal of this study is to evaluate the shear behaviors according to the normal displacement confinement condition including free normal displacement (FND) and constrained normal displacement (CND) during direct shearing. Jumunjin sands were prepared at the different relative densities and loaded at the different normal stresses. The specimens were sheared according to the normal confinement conditions. Experimental results show that shear strengths obtained by the CND tests are higher than those obtained by the FND tests. In addition, for the constrained normal displacement condition, the increment of shear strength increases with the increase of relative density, while the increment of shear strength decreases with the initial normal stress. This study suggests that the effect of confinement condition on the shear strength should be considered when the stability of constrained soils is analyzed.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.285-291
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• 2008

Background: We conducted a case-control study to evaluate the potential association between SERPINA1 genotypes ($M1_{Val}$, $M1_{Ala}$, S, and Z) and the risk COPD. Methods: The study population consisted of 93 patients with COPD and 112 healthy controls. The polymerase chain reaction and restriction fragment length polymorphism for detecting the SERPINA1 variants. Results: The M2 allele of the SERPINA1 gene was significantly associated with the risk of COPD in Koreans. The effect of the M2 allele on the risk of COPD was more pronounced in the subgroup<64 years. Conclusion: These results suggest that SERPINA1 polymorphisms may contribute to a genetic predisposition for COPD. However, additional studies with larger sample sizes are required to confirm our findings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1225-1232
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• 2008

In this paper, we describe a compensation method of diurnal effect which is one of the factors giving large effect on the performance when using ground-wave signals like Loran-C for a backup and substitute navigation system of global satellite navigation system such as GPS, and currently many researches of the topics are doing in USA and in Europe. In order to compensate diurnal effect, we find periodic frequency components by using the Least Square Spectral Analysis (LSSA) method at first and then compensate the effect by subtracting the estimated compensation signal, obtained by using the estimated amplitude and phase of the individual frequency component, from the original signal. In this paper, we propose a simple compensation algorithm and analysis the performance through simulations. From the results, it is observed that the amplitude and phase can be estimated with under 5 % and 0.17 % in a somewhat poor receiving situation with 0 dB Signal to Noise Ratio (SNR). Also, we analyze the obtainable performance improvement after compensation by using the measured Loran-C data. From the results, it is observed that we can get about 22 % performance improvement when a moving average with 5 minutes interval is employed.

• The Korean Journal of Mycology
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• v.40 no.3
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• pp.164-173
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• 2012

For development of new high-value Korean traditional fermented food by using bioactive fungi and bacteria, Nuruk, Makgeolli and Cheonggukjang were prepared by mold, yeasts and bacteria from Korean traditional fermented foods and their physiological functionalities were investigated. Aspergillus oryzae N152-1 Nuruk showed the highest antihypertensive angiotensin I-converting enzyme inhibitory activity(57.2%), and Makgeolli made by Saccharomyces cerevisiae Y111-5 and commercial JS Ipguk (solid cultures of saccharifying enzyme-producing mold) was showed 42.0% of anti-obesity ${\alpha}$-glucosidase inhibitory activity. Among various Cheonggukjang, No 463 Cheonggukjang made by Brevibacterium iodinum NCDO 613(T) was showed the highest fibrinolytic activity (size of clear zone: 28 mm) and good anti-obesity ${\alpha}$-glucosidase inhibitory activity.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.35-40
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• 2013

In this study, the influence on the surface passivation properties of crystalline silicon according to silicon wafer thickness, and the correlation with a-Si:H/c-Si heterojunction solar cell performances were investigated. The wafers passivated by p(n)-doped a-Si:H layers show poor passivation properties because of the doping elements, such as boron(B) and phosphorous(P), which result in a low minority carrier lifetime (MCLT). A decrease in open circuit voltage ($V_{oc}$) was observed when the wafer thickness was thinned from $170{\mu}m$ to $50{\mu}m$. On the other hand, wafers incorporating intrinsic (i) a-Si:H as a passivation layer showed high quality passivation of a-Si:H/c-Si. The implied $V_{oc}$ of the ITO/p a-Si:H/i a-Si:H/n c-Si wafer/i a-Si:H/n a-Si:H/ITO stacked layers was 0.715 V for $50{\mu}m$ c-Si substrate, and 0.704 V for $170{\mu}m$ c-Si. The $V_{oc}$ in the heterojunction solar cells increased with decreases in the substrate thickness. The high quality passivation property on the c-Si led to an increasing of $V_{oc}$ in the thinner wafer. Short circuit current decreased as the substrate became thinner because of the low optical absorption for long wavelength light. In this paper, we show that high quality passivation of c-Si plays a role in heterojunction solar cells and is important in the development of thinner wafer technology.

• Elastomers and Composites
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• v.46 no.3
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• pp.211-217
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• 2011

Wood Polymer Composite (WPC) has attracted a great deal of attention in environmental industries due to renewable resources, processability, excellent physical properties and logging regulations for application to housing units and engineering construction materials. In this study, commercial WPCs were prepared by using a modular intermeshing co-rotating twin screw extruder. The effect of three main factors such as wood flour contents, coupling agent concentrations and pre-treatment of wood flour on the properties of WPCs was extensively investigated. It was found that tensile strength and thermal stability were decreased with increasing wood flour contents whereas the water absorption was increased. Addition of maleic anhydride grafted polypropylene (PP-g-MA) into WPC exhibited better physical properties. On the contrary, the water absorption was slightly decreased with PP-g-MA. Finally the sample, which was prepared with pre-treated wood flour, represented the highest tensile strength. However, the water absorption of the sample was increased due to the transition of crystalline structure of cellulose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1258-1264
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• 2017

The effects of two cooking methods (grilling and boiling) on fat content, fatty acid composition, vitamin A, and vitamin E levels of chicken (breast, wing, thigh, and leg) were investigated. Cooking loss was in the range of 19.09~41.17%, and grilled chicken showed higher cooking loss than boiled chicken in all parts except the thigh. All treatments enhanced fat content except boiled chicken breast. Fatty acid contents of chicken significantly increased or decreased after heat treatments (P<0.05). Grilled wing showed the highest levels of saturated (SFA) and unsaturated fatty acids (UFA), and the highest UFA/SFA ratio was detected in boiled thigh. The highest content of trans fatty acids was detected in boiled wing (137.67 mg/100 g), although no significant difference with grilled wing (P>0.05), and trans fatty acids in breast was not detected. The content of vitamin A tended to decrease with heating in all chicken parts, whereas the content of vitamin E varied depending on the part and cooking method. In other words, vitamin E content of wing decreased after cooking, whereas contents of thigh and leg significantly increased after cooking (P<0.05). These results are helpful for choosing the best cooking method according to the part of the chicken for proper consumption of fats and vitamins.