• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.158-173
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• 2012

The objectives of this study were to analyze the longitudinal gradient and temporal variations of water quality in Daecheong Reservoir in relation to the major inflowing streams from the watershed, during 2001~2010. For the study, we selected 7 main-stream sites of the reservoir along the main axis of the reservoir, from the headwater to the dam and 8 tributary streams. In-reservoir nutrients of TN and TP showed longitudinal declines from the headwater to the dam, which results in a distinct zonation of the riverine ($R_z$, M1~M3), transition ($T_z$, M4~M6), and lacustrine zone ($L_z$, M7) in water quality, as shown in other foreign reservoirs. Chlorophyll-a (CHL) and BOD as an indicator of organic matter, were maximum in the $T_z$. Concentration of total phosphorus (TP) was the highest (8.52 $mg\;L^{-1}$) on March in the $R_z$, and was the highest (165 ${\mu}g\;L^{-1}$) in the $L_z$ on July. Values of TN was the maximum (377 ${\mu}g\;L^{-1}$) on August in the $R_z$, and was the highest (3.76 $mg\;L^{-1}$) in the $L_z$ on August. Ionic dilution was evident during September~October, after the monsoon rain. The mean ratios of TN : TP, as an indicator of limiting factor, were 88, which indicates that nitrogen is a surplus for phytoplankton growth in this system. Nutrient analysis of inflowing streams showed that major nutrient sources were headwater streams of T1~T2 and Ockcheon-Stream of T5, and the most influential inflowing stream to the reservoir was T5, which is located in the mid-reservoir, and is directly influenced by the waste-water treatment plants. The key parameters, influenced by the monsoon rain, were TP and suspended solids (SS). Empirical models of trophic variables indicated that variations of CHL in the $R_z$ ($R^2$=0.044, p=0.264) and $T_z$ ($R^2$=0.126, p=0.054) were not accounted by TN, but were significant (p=0.032) in the $L_z$. The variation of the log-transformed $I_r$-CHL was not accounted ($R^2$=0.258, p=0.110) by $I_w$-TN of inflowing streams, but was determined ($R^2$=0.567, p=0.005) by $I_w$-TP of inflowing streams. In other words, TP inputs from the inflowing streams were the major determinants on the in-reservoir phytoplankton growth. Regression analysis of TN : TP suggested that the ratio was determined by P, rather than N. Overall, our data suggest that TP and suspended solids, during the summer flood period, should be reduced from the eutrophication control and P-input from Ockcheon-Stream should be controlled for water quality improvement.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.93-98
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• 1994

This study aims to find the theoretical consideration of the basic simularity rule between scale model experiment and real building as a results ; 1. In the case of room acoustics, $f_m=n\cdot{f_r}\;T_m=T_r/n\; \alpha_m(f_m)=\alpha_r(f_r)$ 2. That of sound Insulation : $TL_m(f_m)=TL_r(f_r)$

• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1045-1052
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• 2002

Hyperhomocysteinemia, resulted from an interaction between the mutation of MTHFR gene and B vitamin deficiency, is suggested as a possible cause for complications and adverse outcomes of pregnancy. The purpose of the present study was to investigate the relationship between the intakes of B vitamins and serum homocysteine concentrations with the C677T mutation in the MTHFR genotypes in 135 normal pregnant women of 24-28 weeks of gestation. Dietary intake of B vitamins did not differ among the three genotypes, but the negative correlation between dietary folate intake and the serum homocysteine level was the strongest in the T/T type (r ＝ -0.249) than in other genotypes (C/T: r＝ -0.040, C/C:r＝ 0.126, p＜0.05). Among the subject with the T/T type, the pregnant women who consumed folate less than 50% of the RDA had higher serum homocysteine levels than those who consumed folate greater than 125% of the RDA (10.4$\pm$5.9 vs 7.0$\pm$1.5 $\mu$mol/L, p＜0.05). Serum homocysteine levels were higher in the women with micronutrient supplements than those with no supplements in the T/T type, but such relation was not present in the C/C or the C/T type. In conclusion, serum homocysteine concentrations were influenced by the interrelationship between the MTHFR polymorphisms and dietary folate intake or micronutrient supplementation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.107-107
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• 1993

결과 및 고찰: 이 약의 흰쥐에서의 체내동태는 혈중농도로 볼 때 2-exponential pharmacokinetics에 따르고, HPLC법으로 정량한 경우의 $T_1$/$_2$$\alpha$, $T_1$/$_2$$\beta$, AUC, C $L_{T}$, C $L_{R}$, V $D_{SS}$ 는 각각 1.90min, 21.89min, 1899.36$\mu\textrm{g}$ㆍmin/ml, 10.66ml/min/kg, 7.48ml/min/kg, 0.28l/kg으로 bioassay법과는 약간의 차이를 보였다. 분포특성은 간장과 신장에 많이 이행하였으며, 폐로의 이행도 적지만 관찰되었다. 이 약의 단백결합률은 그 농도가 31.3$\mu$M일 때 42.3%였고 water/n-octanol계에서의 유상으로의 분배는 거의 일어나지 않았다. 이 약의 분포용적이 작은 것은 단백결합 때문이라기보다는 높은 극성때문으로 추정되었다. 이 약의 C $L_{R}$은 GFR의 문헌치보다 컸으며 C $L_{T}$의 약 2/3을 차지하므로 약물소실에 있어서 신장의 기여도가 크고 신배설 과정에 신분비가 관여하고 있음을 알 수 있었다. 이런 사실은 CAZ나 CTX등의 기존 세파계 항생제들과 유사했으며, 추후 다회투여시와 용량의존적 체내동태에 관해 더 많은 연구가 필요하리라 생각되었다.되었다.

• Journal of Life Science
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• v.7 no.4
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• pp.377-383
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• 1997

The acute toxicity effect of triorganotin of trioganotin on the growth of microalgae and shellfish was investigated through flask culture. The value of 120 hr-LC$_{50}$ that is the median lethal concentration of TBTO on the shellfish (R. philipinarum) was found to be 6 $\mu$g/L. The acute toxicity effect of TBTO on T. suecica was obviously shown even at the concentration of 0.5 $\mu$g/L, and the effect diminished as the initial cell density increased. The effect also diminished less in the experiment done under aeration than in that done under non-aeration. To design a chemostat system for the test of chronic toxicity, the culture of T. suecica was executed in photobioreactor. In batch culture, the profiles of chlorophyII a and D.C.W. showed the growth of T. suecica very well, and the maximum specific growth rate was estimated to be 0.54 d$^{-1}$. with this value, as a dilution rate in contimuous culture, pH was nicely maintained between 7 and 9 when air was supplied with 3% CO$_{2}$. From all results and the natural environment of clam, a novel chemostat system was invented. Through this system, we can observe each independent toxicity effect of TBTO and plankton and combined toxicity effect as well.

• Bulletin of the Korean Chemical Society
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• v.15 no.1
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• pp.79-83
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• 1994

The organometallic chemical vapor deposition of single precursors, $[Me_2Al({\mu}-NHR)]_2\;(R=^iPr,\;^tBu)$, for alumininum nitride thin films has been investigated to evaluate their poroperties as potential precursors. In chemical vapor deposition processes the gas phase products scattered from a Ni(100) substrate were analyzed by mass spectrometry and the deposited films were characterized by X-ray photoelectron spectroscopy (XPS). The optimum temperatures for the formation of AlN films have been found to be between 700 K and 800 K. Carbon contamination of the films seems to be attributed mainly to the methyl groups bonded to the aluminum atoms. It is apparent that $^tBu$ group is better than $^iPr$ group as a substituent on the nitrogen atom of the single precursors for the AlN thin film formation.

• Proceedings of the Korean Society of Toxicology Conference
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• 1998.10a
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• pp.36-36
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• 1998

Tumorigenicity of benzo(a)pyrene (BP) and benzo(a)pyrene diol epoxides ((+)BPDE-1, (-)BPDE-1) was investigated in transgenic TG-AC mice carrying v-Ha-ras oncogene fused to the promoter of the mouse embryonic a-like, z-globin gene. Animals were topically treated twice per week for 25weeks with BPDE (10$\mu$g/mouse) and BP (10, 20, 40$\mu$g/mouse). In addition, animals were treated with BPDE or BP (initiated) followed by TPA (2$\times$2.5$\mu$g/week, for 4 weeks) for promotion study. In the continuous treatment of BPDE or BP, animals treated with 40$\mu$g BP showed $100\%$ tumor response after 20 weeks, $40\%$ of mice for 20$\mu$g BP, and $20\%$ for (+)BPDE-1, but (-)BPDE-1 and 10$\mu$g BP did not show any tumor response. After 25 weeks, most tumors turned out to be carcinomas in animals treated with 40$\mu$g BP. In BPDE or BP/TPA Initiation-promotion study, papilloma response occurred earlier (6 weeks after TPA treatment) than in continuously treated animals with BPDE or BP. RT-PCR assay for transgene expression showed that BP or BPOE was not transgene dependent in its tumorigenicity, but TPA was. Several Cytokine genes(TGF-a, TNF-a) and c-myc gene expressions were monitored in skin tissues during BP carcinogenesis. In early stage of BP treatment, the gene expressions were elevated(c-myc,TGF-a) or unchanged(TNF-a) compared to control, but the levels were gradually decreased during both middle and late stages of cacinogenesis, Gene expression levels of skin papillomas in acetone initiated-TPA promoted animals were close to those of middle stage or between middle and late stages. i-NOS was also highly expressed in carcinoma and papilloma, These data suggest that transgene expressions of TG-AC mice were not dependent on BP carcinogenesis and that TG-AC mice were more sensitive to TPA regardless of types of initiators. In addition, genes(TGF-a, c-myc, TNF-a, i-NOS) were modulated in the skin during BP cacinogenesis or TPA promotion.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.150-156
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• 2010

The separation performance of a low-pressure hydrocyclone (LPH) was evaluated for suspended-solids removal in a recirculating aquaculture system (RAS). The dimensions of the LPH were 335 mm cylinder diameter, 575 mm cylinder height, 60 mm overflow diameter, 50 mm underflow diameter, and $68^{\circ}$ cone angle. The inflow rate varied (400, 600, 800, and 1,000 mL $s^{-1}$) with 25%, 25%, 20%, and 10% of bypass ($R_f$), respectively. The maximum total separation efficiency (Et) and reduced separation efficiency (E't) for suspended solids from the effluent of the second settlement tank (before biofiltration) were 58.9% and 45.2%, respectively, at an inflow rate of 600 mL $s^{-1}$ and 25% of $R_f$. The maximum Et and E't for suspended solids from the water supply channel (after biofiltration) were 24.4% and 16%, respectively, at an inflow rate of 1,000 mL $s^{-1}$ and 10% of $R_f$. The maximum grade efficiency (Ei) was 51.6% for a 300 ${\mu}m$ particle size at an inflow rate of 600 mL $s^{-1}$ with 23% of $R_f$. The maximum reduced grade efficiency (E'i) was 37.6% for a 300 ${\mu}m$ particle size at an inflow rate of 1,000 mL $s^{-1}$ with 11% of $R_f$. The results indicate that the separation performance of the LPH for suspended solids removal was size selective and that maximum removal occurred at particle sizes ranging from 300 to 500 ${\mu}m$.

• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.452-460
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• 2018

This study was conducted to investigate the physiological activities of Houttuynia cordata extracts and fractions. H. cordata extracts were extracted with 50% ethanol and the ethyl acetate fractions were obtained from the extracts. Minimum inhibitory concentration (MIC) values of the ethyl acetate fraction for S. aureus and B. subtilis were $78{\mu}g/mL$ and $312{\mu}g/mL$, respectively, indicating the high activity against gram-positive bacteria. The free radical scavenging activity ($FSC_{50}$) for 1,1-diphenyl-2-picrylhydrazyl (DPPH) was higher in the ethyl acetate fraction with $12.00{\mu}g/mL$ compared to that of $27.15{\mu}g/mL$ for 50% ethanol extract. The total antioxidant activity ($OSC_{50}$) values for reactive oxygen species (ROS) produced in $Fe^{3+}-EDTA/H_2O_2$ system by a luminol-dependent chemiluminescence method were 2.91 and $0.983{\mu}g/ml$ for the 50% ethanol extract and ethyl acetate fraction, respectively. To investigate cellular protective effects on the HaCaT cell, the intracellular ROS scavenging activity was measured after UVB irradiation and the ethyl acetate fraction of H. cordata showed the activity in a concentration-dependent from $1.6{\mu}g/mL$ and a reduction rate of 54.3% at a maximum concentration of $12.5{\mu}g/mL$. Also, HaCaT cell protective effect against $H_2O_2$-mediated decreased the cell viability of the ethyl acetate fraction of H. cordata which significantly increased the cell viability from $0.8{\mu}g/mL$ and the maximum cell viability showed 86.9%. The ethyl acetate fraction of the H. cordata extracts was analyzed by TLC and HPLC. As a result, quercitrin, isoquercitrin, hyperoside, chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, rutin and afzelin were identified. From the above results, it was suggested that the extracts and fractions of H. cordata have a potential to be applied in the field of cosmetics as a natural antioxidant/preservative capable of protecting the cell membrane from the oxidative stress by eliminating ROS and exhibiting the antimicrobial effect.

• Archives of Pharmacal Research
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• v.17 no.3
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• pp.194-198
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• 1994

The antitumor effects of the 2E4 and anti--Tac, monoclonal antibodies directed to Il-2 receptor (IL-2R) conjugated with .alpha.-particle emitting radionuclide bismuth-212., were compared. The $^{212}Bi-2E4$ demonstratedspecific cytotocicity to EL4J3, 4, a I$L-2R^+$ cell line, than to EL4J, a $IL-2R^-$ cell line in thymidine incorporation assy. TEX>$^{212}Bi-2E4$ exerted the maximal antitumor effect in that % T/C in C57BL/6 mice implanted with EL4J3.4 ascitic tumor was 331% at the concentration of $50{\;}{\mu}Ci$, while that of $^{212}Bi-anti-Tac$ was 258% at $100{\;}{\mu}Ci$.