• 한국환경과학회지
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• 제23권7호
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• pp.1253-1268
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• 2014

This study was investigated twenty two hazardous chemicals compounds for effluents of nine sewage treatment plants (STPs) and one waste water treatment plant (WWTP) in the Nakdong Ri-ver Basin. They are eleven phthalates(DMP, DEP, DIBP, DBP, BEEP, DNPP, DHP, DCP, DEHP, DNOP, Dinonyl phthalate, seven aliphatic hydrocarbons(n-Tridecane, n-Tetradecane, n-Pentadecan-e, n-Hexadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline, 2-Chloropyridine, 2-N-itrophenol, and Benzophenone. The twenty two compounds were analyzed by gas chromatograp-hy mass spectrometry (GC/MS) with liquid-liquid extraction (LLE). Twenteen of twenty two subs-tances were detected. They were DMP, DEP, DIBP, DBP, DEHP, n-Tetradecane, n-Pentadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline and Benzophenone. Among these, DEHP, DEP and Benzophenone were most frequently observed. They were obtained as $ND{\sim}36.881{\mu}g/L$, $ND{\sim}0.950{\mu}g/L$, $ND{\sim}2.019{\mu}g/L$, respectively. When the substances were calculated the average concentration at 10 points, the maximum average detection concentration was investigated at the Dalseocheon STP.

• 대한지역사회영양학회지
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• 제9권4호
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• pp.483-490
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• 2004

Elevated maternal plasma homocysteine concentrations have been associated with adverse pregnancy outcomes, including birth defects, low birth weight, preeclampsia, spontaneous abortion, placental abruption, and other maternal or fetal complications. The purpose of this study was to assess the maternal plasma homocysteine level during pregnancy and to investigate the relationship between the plasma homocysteine concentrations and pregnancy outcomes. Venous blood samples were drawn from 82 pregnant women who were grouped with gestational age, 1st trimester (n = 26), 2nd trimester (n = 27) and 3rd trimester (n = 29). The concentration of plasma homocysteine was analyzed by HPLC, and pregnancy outcomes including gestational length, maternal weight gain, infant birth weight, and Apgar score were collected with the medical records of the pregnant women. The levels of plasma homocysteine of the pregnant women at the 1st, 2nd, and 3rd trimester were 5.7 $$\pm$ 3.7\mu㏖/L,\;5.6 \pm4.1\mu㏖/L\; and\; 7.0\pm 4.5\mu㏖/L$, respectively, which had not showed any significant difference. The result of this study showed that in case of the pregnant women at the 1st trimester, the maternal plasma homocysteine level of the pregnant women whose gestational length was less than 38 weeks was significantly high (p < 0.01) compared to that of the pregnants whose gestational length was more than 38 weeks. And also, the level of homocysteine of the pregnant women at the 2nd trimester was significantly low when the maternal weight gain was high (p < 0.05). These findings suggest that maternal plasma homocysteine level at early stage of gestation will be a predicter of gestational length and maternal weight gain.

• Journal of Microbiology
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• 제45권4호
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• pp.291-296
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• 2007

Insoluble glucans synthesized by Streptococcus mutans enhance the pathogenicity of oral biofilm by promoting the adherence and accumulation of cariogenic bacteria on the surface of the tooth. The objective of this study was to investigate the effect of Leuconostoc spp. on the in vitro formation of S. mutans biofilm. Three strains, Leuconostoc gelidum A TCC 49366, Leuconostoc mesenteroides ssp. cremoris A TCC 19254 and Leuconostoc mesenteroides ssp. mesenteroides ATCC 8293, were used in this study. They exhibited profound inhibitory effects on the formation of S. mutans biofilm and on the proliferation of S. mutans. The water-soluble polymers produced from sucrose were most strongly produced by L. gelidum, followed by L. mesenteroides ssp. cremoris and L. mesenteroides ssp. mesenteroides. The mean wet weights of the artificial biofilm of S. mutans were also significantly reduced as a result of the addition of the water-soluble polymers obtained from Leuconostoc cultures. According to the results of thin-layer chromatographic analysis, the hydrolysates of the water-soluble polymers produced by Leuconostoc were identical to those of dextran T-2000, forming predominately ${\alpha}-(1-6)$ glucose linkages. These results indicate that dextran-producing Leuconostoc strains are able to inhibit the formation of S. mutans biofilm in vitro.

• 생약학회지
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• 제37권1호통권144호
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• pp.42-47
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• 2006

The contents of quercetin glyciside in Saururus chinensis Baill was higher in the 2nd year, 1st year and 3rd year in leaves, and in the 1st year, 3rd year and 2nd year in stems in that orders. Content of lignans in the rhizome was not significantly different cultivated years. The total phenolics, quercetin glycoside and EDA of plant parts were higher in order of flower, leaf and chopping sample. The total phenolics and EDA of stem were much lower than parts and quercetin glycoside was not detected.

• 한국환경과학회지
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• 제32권9호
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• pp.671-674
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• 2023

This study was conducted to evaluate the effects of using Hermetia illucens larvae as environmental purification insects on ammonia and Hanwoo manure for 15 days in the Hanwoo farms. H.illucens larvae were allocated into four treatment groups and three replicates using a randomized block design. The treatments were as follows: control, normal 1000 g of Hanwoo manure, T1, 1000 g of Hanwoo manure + 100 g of 2nd instar H.illucens L. larvae, T2, 1000 g of Hanwoo manure + 100 g of 3rd instar H.illucens L. larvae, and T3, 1000 g of Hanwoo manure + 100 g of 4th instar H.illucens L. larvae. After 0 days, ammonia fluxes did not occur in the 2nd, 3rd, and 4th instar H.illucens larvae treatments (p<0.05). Among the characteristics of Hanwoo manure, the pH and nitrogen content increased for each larvae instar of H.illucens, whereas ADF and NDF content decreased (p<0.05). In particular, nitrogen contents were found to be highest in the 3rd instar larvae of H.illucens owing to their greater ability to decompose Hanwoo manure than larvae at other growth stages.

• 한국가정과학회지
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• 제4권1호
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• pp.36-45
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• 2001

This study was performed to determine the changes of maternal iron status during pregnancy cross sectionally, and to evaluate the appropriateness of the cut-off points of hemoglobin (Hb). hematocrit (Hct), serum transferrin receptor (sTfR) and sTfR : ferritin ratio for assessing iron deficiency status based on serum ferritin level (< 12${\mu}g$/L). Serum Hb concentrations in the first trimester were significantly higher (p < 0.05) than those in the second and third trimester. Serum levels of iron and ferritin in the third trimester were significantly lower (p < 0.05) than those in the first and second trimester. On the other hand, sTfR:ferritin ratios in the third trimester were significantly higher (p < 0.05) than those in the first and second trimester. sTfR concentrations did not change significantly during pregnancy. The appropriate cut-off points of Hb were 11.5g/dL for whole period of pregnancy. 12.0g/dL for 1st trimester. and 11.5g/dL for both 2nd and 3rd trimester. The good cut-off points of Hct were 34% for whole period of pregnancy. 36% for 1st trimester. and 34% for both 2nd and 3rd trimester The suitable cut-off points of TIBC were 400${\mu}g$/dL for whole period of pregnancy. 360${\mu}g$/dL for 1st trimester, and 400${\mu}g$/dL for both 2nd and 3rd trimester. Any cut-off point of sTfR could not be selected because of its low sensitivity and specificity. The proper cut-off point of sTfR : ferritin ratio was 600 or 650 for all the periods determined except the first trimester. In conclusion, there were no reliable cut-off levels of sTfR and those of sTfR : ferritin ratio showed low specificity. The cut-off values of Hb and Hct for assessing iron deficiency were slightly higher than the values used to evaluate anemia. Thus, if appropriate cut-off levels were applied, Hb. Hct, or TIBC might be useful indices for evaluating iron deficiency as well as anemia.

• 한국재료학회지
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• 제10권7호
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• pp.478-481
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• 2000

$Pb(Mg_{1/3}Nb_{2/3})O_3$의 $Pb_{2+}$ 자리에 치환되어 전자주게 역할을 하는 $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$ 등이 10mol% 첨가된 단일상의 $Pb(Mg_{1/3}Nb_{2/3})O_3$ 소결체를 합성하여 이들의 B자리 양이온 질서배열구조를 XRD와 TEM을 이용하여 분석하였다. 전자 주게가 첨가되지 않았을 때에는 XRD패턴에서 공간군 Pm3m에 해당하는 기본 회절선(fundamental reflection) 만 검출되었으나 전자 주게가 첨가된 경우에는 $Mg_{2+}$와 $Nb_{5+}$의 1:1 질서배열로 인하여 단위포의 체적이 8배가 되어(h/2 k/2 l/2)(h,k,l 모두 홀수) 조격자 회절선(superlattice reflection)이 검출되었다. TEM 제한시야회절패턴(selected area diffraction pattern)에서는 전자 주게의 첨가 여부에 관계없이 초격자 회절점이 검출되었으나 전자 주게가 첨가된 경우에 기본 회절점에 대한 초격자 반사점의 상대적인 강도가 현저히 증가하였다. TEM 암시양상(dark field image)에서는 전자 주게가 첨가되었을 때에만 반상경계(antiphase boundary)가 관찰되었다. 이로부터 전자 주게인 $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$등이 $Pb_{2+}$를 치환함에 따라 $Pb(Mg_{1/3}Nb_{2/3})O_3$의 B자리 양이온 1:1 질서배열이 강화됨을 실험적으로 증명하였다. 얻어진 결과는 전하보상기구에 근거하여 해석하였다.

• 한국세라믹학회지
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• 제39권1호
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• pp.26-32
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• 2002

유전율(${\varepsilon}_r$) 126, $Q{\cdot}f_{0}(GHz)$값은 2240, 공진주파수의 온도계수(${\tau}_f$) $+68\;ppm/^{\circ}C$의 특성을 갖는 $0.3CaTiO_3-0.7(Li_{1/2}Nd_{1/2})TiO_3에\;Nd_2O_3$를 첨가하였을 때의 마이크로파 유전특성의 변화에 대해 고찰하였다. 유전율(${\varepsilon}_r$)은 5wt% $Nd_2O_3$ 첨가시 131로 가장높은 값을 나타내었으며, 이후 첨가량이 증가함에 따라 유전율은 감소함을 보였다. $Q{\cdot}f_{0}(GHz)$값은 9wt% $Nd_2O_3$ 첨가시까지 입계의 치밀화 등에 의해 3533까지 증가하다가 이후 l8wt% $Nd_2O_3$첨가시까지는 비정상적 입계성장의 영향으로 감소함을 보이고, 25 wt% 이상 첨가시에는 제2상인 $Nd_2Ti_2O_7$상의 영향으로 다시 증가함을 보였다. 공진주파수의 온도계수($({\tau}_f$)는 $Nd_2O_3$첨가에 따라 최초의 $+68\;ppm/^{\circ}C$에서 30wt% $Nd_2O_3$ 첨가시 $-46\;ppm/^{\circ}C$까지 변화함을 알 수 있었다. $0.3CaTiO_3-0.7(Li_{1/2}Nd_{1/2})TiO_3에\;Nd_2O_3$를 9wt% 첨가하여 $1425^{\circ}C$에서 3시간동안 소결한 시편에서 유전율(${\varepsilon}_r$)은 108, $Q{\cdot}f_{0}(GHz)$값은 3533, 공진주파수의 온도계수(${\varepsilon}_f$)가 $+6\;ppm/^{\circ}C$인 우수한 마이크로파 유전특성을 얻을 수 있었다.

• Macromolecular Research
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• 제8권1호
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• pp.12-18
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• 2000

Six aromatic polyesters with ether-linkages were prepared from 4,4'-oxybis(benzoic acid) and naphthalenediol (ND) isomers which were 1,4-, 1,5-, 1,6-, 2,3-, 2,6- and 2,7-derivatives. The solution viscosity numbers ranged from 0.23 to 0.65 dL/g. The glass transition temperatures ranged from 142 to 179$\^{C}$. The initial decomposition temperatures were all above 400$\^{C}$, and the residue weights at 600$\^{C}$ were in the range of 50-64%. Only the polyesters derived from 1,5- and 2,6-NDs, which have a linear linking mode, were found to be semicrystalline and could form thermotropically nematic phase. Multiple melting phenomena and annealing of the polyester derived from 1,5-ND and related polymers are described. The experimental results show that the polyester derived from 1,4-ND of linear shape was amorphous and non-liquid crystalline. Particularly, the polyester derived from 2,3-ND could form a smectic mesophase as banana-shaped molecules, and this is ascribed to the C/sub_2v/ symmetry where highly kinked molecules are packed in the same direction.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1345-1348
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• 2008

Titanium dioxide ($TiO_2$) shows antibacterial effects when exposed to near ultra violet (UV) light. In this study, $TiO_2$ photocatalytic continuous reactor was designed and applied to food-borne pathogens such as Vibrio parahaemolyticus ATCC 17802, Salmonella choleraesuis ATCC 14028, and Listeria monocytogenes ATCC 15313. $TiO_2$ films were prepared by conventional sol-gel dip-coating method using titanium tetra iso-propoxide (TTIP). The antibacterial activity of photocatalytic reactor with various flow rates and UV-A illumination time showed effective bactericidal activity. As the UV-A illumination time increased, survival rates of those bacteria decreased. After 60 min of UV-A illumination, the survival rates of V. parahaemolyticus and S. choleraesuis were less than 0.1%. However, that of L. monocytogenes was about 5% at that time point. These results present an effective way to exclude pathogenic bacteria from aqueous foods.