• 한국패류학회지
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• 제32권1호
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• pp.37-43
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• 2016

This study was carried out to determine the optimal water temperature for the embryonic development and laboratory culture of larvae of an intertidal mud snail, Nassarius festivus. The embryos and hatched veliger larvae of N. festivus were incubated at six different temperatures (5, 10, 15, 20, 25 and $30^{\circ}C$). Developmental time for each stage decreased as water temperature increased. The elapsed time to develop to the veliger larva at 15, 20, 25 and $30^{\circ}C$ was 559, 155, 131 and 103 hrs, respectively. At 5 and $10^{\circ}C$, embryo developed to veliger larvae but failed to hatch out of the egg capsule. In contrast, all embryos successfully hatched in the temperature range from 15 to $30^{\circ}C$. The biological minimum temperature during the embryonic development of N. festivus was estimated to be $9.5{\pm}0.4^{\circ}C$. The cumulative water temperatures for blastula, gastrula and veliger stages were calculated as $111{\pm}84$, $486{\pm}185$, $1,164{\pm}72^{\circ}C$, respectively. Temperature also affected the larval survival. Five days after hatching, more than 84% of larvae survived at all experimental temperatures. However, survival began to decrease after 6 days. It was 0% at $30^{\circ}C$. Survival of larvae incubated for 8 days was higher at 15 and $20^{\circ}C$ than other experimental temperatures. We therefore suggest that the optimal range of temperature for embryonic development and larval survival of N. festivus is $15-20^{\circ}C$.

• 한국미생물·생명공학회지
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• 제27권2호
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• pp.129-135
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• 1999

EH-1 was highest at 9 days of incubation. This regrowth and enzymatic activity of Haloarcular sp. EH-1 was highest at 9 days of incubation. This amylase was purified by acetone fractionation, DEAG-Cellulose column chromatography, 1st Sephadex G-75 gel filtration, CM-Cellulose column chromatography and 2nd Sephadex G-75 gel filtration. The amylase was purified about 98.64 fold with a yield of 11.75%. The molecular weight of amylase was estimated to be about 43,000and 40,000 by gel filtration and SDS-polyacrylamide gel electrophoresis, respectively, suggesting that the enzyme was a monomer. Amylase had an optimal temperature of 4$0^{\circ}C$, and an optimum pH of 7.0, and the thermal stability was observed the above 50% at 10$0^{\circ}C$ after 1 hour, and the stable range of pH was 6.0 to 8.0. The enzymatic activity was increased in the presence of 10 mM 2-mercaptoethanol, slightly by 10 mM SnCl2.2H2O.FeCl2.4H2O.CuCl2.2H2O.HgCl2.6H2O and SDS. End products from soluble starch were glucose, maltose and maltotriose, and Km value for soluble starch was 2.5mg/ml.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.463-467
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• 2004

폐광산 지역내 사문암, 석회암 및 호온펠스와 지하수의 수질과의 상호관계를 비교 연구하였다. 암상별로 지하수를 채수하여 산화환원전위(Eh)와 수소이온농도(pH)를 측정하였다. Eh-pH 다이어그램을 작성한 결과 pH는 중성에서 약알칼리성으로 나타났으며, Eh는 -316.5～202.1 mV의 범위로 나타났다. 암상별 지하수의 파이퍼 다이어그램 분석 결과, 사문암 지/ 역에서는 $Mg^{2+}$-SO$_{4}$$^{2-}$ 형, 석회암 지역에서는 $Ca^{2+}$-HCO$_{3}$$^{-}$형이 우세하게 나타났다. 또한 호온펠스 지역에서는 $Na^{+}$＋K＋와 CO$_{3}$$^{2-}$ ＋HCO$_{3}$$^{-}$ 성분의 비가 다른 지역보다 높게 나타났다. 국부적인 폐광산 지역에서도 지하수내 주이온성분이 암상별 광물의 특징을 잘 반영하는 것으로 나타났다.

• Earthquakes and Structures
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• 제12권2호
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• pp.177-189
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• 2017

For energy-based seismic design, a simplified normalized cumulative hysteretic energy spectrum proposed for obtaining hysteretic energy as energy demand is the main objective in this paper. The dimensionless parameter, ${\beta}_{Eh}$, is presented to express hysteretic energy indirectly. The ${\beta}_{Eh}$ spectrum is constructed directly through subtracting the hysteretic energy of single degree-of-freedom (SDOF) system energy equation. The simplified ${\beta}_{Eh}$ spectral formulation as well as pseudo-acceleration spectrum of modern seismic provisions is developed based on the regression analysis of the large number of seismic responses of SDOF system subjected to earthquake excitations, which considers the influence of earthquake event, soil type, damping ratio, and ductility factor. The relationship between PGV and PGA is established according to the statistical analysis relied on a total of 422 ground motion records. The combination of ${\beta}_{Eh}$ spectrum and PGV/PGA equation allows determining the cumulative hysteretic energy as a main aseismic design indicator.

• 한국산업보건학회지
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• 제26권4호
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• pp.396-403
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• 2016

Objectives: The study is to evaluate biological monitoring and risk assessment for epichlorohydrin-bisphenol A resin exposed from waterproofing or finishing work in the apartment building construction. Methods: Subjected workers were working on spray-painting and waterproofing work for 8 hours per day every 20 days. The urine samples were collected at the end of 20 days working period. For urinary bisphenol A as metabolite from epichlorohydrin-bisphenol A exposure, urine samples were analyzed with liquid chromatography mass-mass spectrometry(HPLC-MS/MS). Results: Geometric means of urinary bisphenol A(BPA) with no hydrolysis and with enzymic hydrolysis(BPA-EH) in the workers were $1.10{\mu}g/L$ and $2.90{\mu}g/L$. BPA-EH was 4 times higher than that of control group. The factors for working period and ages did not affect the variation of BPA and BPA-EH. The levels for BPA and BPA-EH were not higher than 95th percentile for exposure on human-life environment. Conclusions: The BPA and BPA-EH were therefore effective biological markers for epichlorohydrin-bisphenol A exposure workers, but not seem to hazardous exposure level. Waterproofing work in construction workshop is required to measuring work environment and health care management for the workers.

• 미생물학회지
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• 제29권1호
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• pp.56-62
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• 1991

Extremely halophilic bacteria isolated from salterns at Mado, Kyunggido, Korea, were identified and investigated on their salt requirements. The results have shown that six strains were identified to be belonged to the genus Halobacterium and three strains identified as the fenus Halococcus. Among them, the optimal NaCl concentration for growth of Halobacterium sp. EH10 was at 4.2M and no growth occurs below 2.0M NaCl. The strain, EH10, is nonmotile and showed acid production from glucose, fructose and maltose while H. salinarum is motile and does not produce acid from any carbohydrates. On the other hand, the strain EH10 does not utilize readily glucose while a number of sugars are readily utilized for growth with acid production by H. saccharovorum. Thus, the isolate, EH10, was classified into the genus Halobacterium and could be a novel species of the genus by its main morphological and physiological features including G+C content. The optimal temperature for growth of the isolate, EH10, was 50.deg.C. But this strain did not grow when NaCl was replaced with KCl.

• The Journal of Advanced Prosthodontics
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• 제8권1호
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• pp.62-69
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• 2016

PURPOSE. The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. MATERIALS AND METHODS. Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. RESULTS. The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). CONCLUSION. Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

• Journal of Plant Biotechnology
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• 제49권1호
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• pp.90-98
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• 2022

This study was performed to determine the optimal ratio for preparing an extract comprising the Ecklonia cava and Hizikia fusiformis complex as a therapeutic material for alleviating inflammatory respiratory diseases. First, to examine the optimal ratio for preparing the complex (SD-EH), Ecklonia cava and Hizikia fusiformis extracts were used; four extracts with different mixing ratios were prepared. The effects of the SD-EH extract on MUC5AC mRNA expression in PMA-treated NCI-H292 cells were analyzed; it was confirmed that the MUC5AC expression was significantly reduced after treatment with the SD-EHA-001 (E(100) : H(0)), SD-EHB-001 (E(90) : H(10)), SD-EHC-001 (E(80) : H(20)), and SD-EHD-001 (E(70) : H(30)) extracts. Western blotting was used to determine whether the SD-EH extract affects the expression levels of COX-2 and MMP-9 in PMA-treated A549 cells. The protein expression levels of COX-2 and MMP-9 were significantly lower (p < 0.001) in the cells treated with the SD-EHC-001 (E(80):H(20)), SD-EHD-001 (E(70) : H(30)), and SD-EHE-001 (E(60) : H(40) extracts than in the cells treated with PMA alone. The SD-EHC-001 (E(80) : H(20)) extract markedly downregulated the expression levels of MUC5AC, COX-2, and MMP-9. Therefore, the SE-EH extract may serve as a potential therapeutic agent for treating inflammatory respiratory diseases.

• Natural Product Sciences
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• 제21권1호
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• pp.34-41
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• 2015

The objective of this study is to characterize a toxicity of Epimedii Herba (EH) in F344 rats and to find a dose levels for the 13 weeks toxicity study. EH is well known as medicinal herb in many Asian countries for traditional medicines of antibacterial and antiviral effects, estrogenic and antiestrogenic effects, and for treatment of osteoporosis, hypotensives, fatigue, kidney disorders, and related complications. However, the indispensable and basic information of toxicological evaluation of EH extract is insufficient to support its safe use. Therefore, we conducted toxicological evaluation of this drug in compliance with OECD and MFDS guideline in this study. The extract of EH was administered orally to F344 rats at dose levels of 0, 500, 1000, 2000, 3500, and 5000 mg/kg/day for 2 weeks. Each group was composed of 5 male and female rats. In this study, there were no treatment of EH-related adverse changes in clinical observations, mortality, body weights, food consumption, urinalysis, gross finding at necropsy, and organ weight examination. Total red blood cell count, hematocrit, mean corpuscular hemoglobin concentration, total cholesterol, and phospholipid were decreased in males and females at 5000 mg/kg/day compared to the control animals. Mean corpuscular volume and reticulocyte counts were increased in males and females at 5000 mg/kg/day compared to control animals. Therefore, we recommend that dose level of 5000 mg/kg/day is a highest treatment group in 13-week EH extract exposure study for further toxicity assessment.

• 지질공학
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• 제12권4호
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• pp.439-457
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• 2002

금정산-백양산 일원에 분포하는 50개소의 용천수와 6개소의 지하수에 대하여 9개 물리화학적 성분(온도, pH, Eh, EC, TDS, DO, 염분농도, 알칼리도, 용출량)을 측정하였다. 용천수의 pH는 5.06~8.38, 알칼리도는 7.93~102.21mg/1, EC는 $9.5~270\mu\textrm{s}/cm$, Eh는 64.2~685.9mV, DO는 4.57~12.13mg/l, 용출량은 4.26~182.2ml/s이다. 물리화학적 성분들의 통계적인 특성을 알기 위하여 일반통계분석을 실시하였으며 물리화학적 성분들간의 상관성을 분석하였다. 또한 용천수와 지하수의 물리화학적 성분을 비교하였다. DO, pH, Eh, EC, 알칼리도, 용출량의 공간적인 분포 특성을 알기 위하여 크리깅이 수행되었으며, 계산된 값을 성분들간의 공간적인 분포 비교를 위하여 표준화시켰다. 표준화된 값을 이용한 물리화학적 성분의 등치선도를 작성하여 각각의 성분의 이상대를 파악하였으며 서로 다른 성분들의 이상대를 비교 검토하였다.