• 한국대기환경학회지
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• 제15권4호
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• pp.393-402
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• 1999

Precipitation samples were collected by the wet-only sampling method in Iksan in the northwest of Chonbuk from March 1995 to February 1997. These samples were analyzed for the concentration of ion components, in addition to pH and electrical conductivity. The annual mean pH of precipitation was 4.8 and the seasonal trend of pH was shown to be low in Fall and Winter(4.5), middle-ranged in Spring(4.7) and high in Summer(5.0). The frequency of pH below 5.6 was about 71%. The seasonal pattern of pH frequency was found to be different in each season. In the case of the pH less than 5.0, the frequency was higher in Spring, Fall and Winter than in Summer, especially higher in Fall than in other seasons. The concentrations of analysed ions showed a pronounced seasonal pattern. However, major ion species for all seasons were $NH^+_4,;Ca^{2+};and;Na^+$ among cations and $SO^{2-}_4,;Cl^-;and;NO^-_3$ among anions. The major acidifying species appeared to be $nss-SO^{2-}_4;and;NO^-_3$, and the main bases responsible for the neutralization of precipitation acidity were $nss-Ca^{2+};and;NH^+_4$. The potential acidity of precipitation, pAi, was found to be between 3.0 and 5.0 for total samples, while the measured pH was approximately between 3.9 and 7.8. The seasonal trend of pAi showed a decreasing order: Summer (4.3), Winter(4.0), Spring and Fall(3.8). During the Fall, both pAi and pH were especially very low, which indicated that during this period the potential acidity of precipitation was high but the neutralizing capacity was low. For Spring, pAi was very low but pH was slightly high. This was likely due to the large amount of $CaCO_3$ in the soil particles transported over a long range from the Chinese continent that were incorporated into the precipitation, and then neutralized the acidifying species with its high concentraton.

• 폴리머
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• 제35권5호
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• pp.375-377
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• 2011

두 단계 스핀 코팅 방법을 사용하여 세라믹 체적 분율 0.10과 0.13의 $PbTiO_3$/P(VDF/TrFE) 0~3형 복합재료를 제작하고 분석하였다. 0~3형 $PbTiO_3$/P(VDF/TrFE) 복합재료를 SEM 전자현미경 사진으로 성공적으로 확인할 수 있었다. 이러한 전자현미경 사진을 통하여 복합재료의 0~3형 구조를 재확인하였다. 0~3형 $PbTiO_3$/P(VDF/TrFE) 복합재료는 P(VDF/TrFE) 공중합체보다 센서용 전기적 특성이 우수함을 나타내었다. 그러므로 이러한 낮은 유전상수와 높은 초전계수를 나타내는 0~3형 $PbTiO_3$/P(VDF/TrFE) 복합재료는 더 높은 성능을 나타낼 수 있는 새로운 초전형 센서 재료로 사용될 수 있다.

• 한국대기환경학회지
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• 제23권1호
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• pp.14-28
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• 2007

This study presented the selection of ozone ($O_3$) potential factors and designed and assessed its potential prediction model using multiple-linear regression equations in Ulsan area during the springtime from April to June, $2000{\sim}2004$. $O_3$ potential factors were selected by analyzing the relationship between meterological parameters and surface $O_3$ concentrations. In addition, cluster analysis (e.g., average linkage and K-means clustering techniques) was performed to identify three major synoptic patterns (e.g., $P1{\sim}P3$) for an $O_3$ potential prediction model. P1 is characterized by a presence of a low-pressure system over northeastern Korea, the Ulsan was influenced by the northwesterly synoptic flow leading to a retarded sea breeze development. P2 is characterized by a weakening high-pressure system over Korea, and P3 is clearly associated with a migratory anticyclone. The stepwise linear regression was performed to develop models for prediction of the highest 1-h $O_3$ occurring in the Ulsan. The results of the models were rather satisfactory, and the high $O_3$ simulation accuracy for $P1{\sim}P3$ synoptic patterns was found to be 79, 85, and 95%, respectively ($2000{\sim}2004$). The $O_3$ potential prediction model for $P1{\sim}P3$ using the predicted meteorological data in 2005 showed good high $O_3$ prediction performance with 78, 75, and 70%, respectively. Therefore the regression models can be a useful tool for forecasting of local $O_3$ concentration.

• Asian-Australasian Journal of Animal Sciences
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• 제22권9호
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• pp.1248-1255
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• 2009

This study was carried out to evaluate the fatty acid composition in Nellore cows supplemented with either linseed (n-3) or canola grains (n-6 and n-9). Fifteen Nellore cows, aged five years and bodyweight 550 kg${\pm}$48 kg, were randomly distributed to the following treatments: CON (control), LIN (linseed) and CAN (canola grains). The cows were fed for 80 days. The concentrations of C18:0, C18:2 n-6 and C20:3 n-6 fatty acid were higher (p<0.10) in CON blood plasma in comparison to follicular liquid. Likewise, PUFA, n-6 contents, PUFA:SFA and n-6:n-3 ratios were higher (p<0.10) in blood plasma. On the other hand, C18:1 n-9, C22:5 n-3, MUFA and n-3 contents were lower (p<0.10) in blood plasma. C18:0, C18:2 n-6, C18:3 n-3, C22:5 n-3, PUFA, n-6, n-3 contents and PUFA:SFA ratio were higher (p<0.10) in LIN blood plasma than in the follicular liquid. Nevertheless, C14:0, C16:0, C16:1 n-7, PUFA, C16:0, C18:1 n-9 and MUFA contents were lower (p<0.10) in LIN blood plasma. On treatment CAN, the C18:0 and SFA contents, and n-6:n-3 ratios were higher (p<0.10) in blood plasma. However, C20:3 n-6, C22:5 n-3, PUFA and n-3 contents were lower (p<0.10) in blood plasma. C16:0, C18:0, PUFA, SFA contents and PUFA:SFA ratio did not differ (p>0.10) among the treatments. C14:0, C16:1 n-7, C18:2 n-6 and n-6 contents were higher (p<0.10) for CON and CAN than LIN. C17:1 n-7, C20:4 n-6 and C 22:0 contents were higher (p<0.10) for CAN than CON and LIN. C18:1 n-9, C18:3 n-3, MUFA and n-3 contents were higher (p<0.10) for LIN and CAN than CON. C20:3 n-6 content and n-6:n-3 ratio were higher (p<0.10) for CON than LIN and CAN. C22:5 n-3 content were higher (p<0.10) for CON and LIN than CAN. The concentrations of fatty acids in blood plasma and follicular liquid were not correlated for any fatty acid, independent of the treatment studied. Canola grain added to the diet of Nellore cows resulted in increased concentrations of fatty acids n-6 and n-3 in follicular liquid.

• 한국미생물·생명공학회지
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• 제24권1호
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• pp.92-100
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• 1996

For the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(3HB-co-3HV)) from butyric acid and valeric acid, 10 strains of bacteria capable of producing P(3HB-co-3HV) were isolated from soil. Among them, the strain HJ-067 showed the best ability of producing P(3HB-co-3HV), and was indentified as a Azotobacter sp. For the production of P(3HB-co-3HV), the optimum concentrations of butyric and valeric acid were 3.0g/l, respectively. The most effective nitrogen source was $(NH_4)_{2}SO_4$ at an optimum concentration of 0.75g/l, which was equivalent to 21.36 in C/N ratio. Deficiency of the cationic metal ions ($Zn^{2+},\;Co^{2+},\;Mn^{2+}$) in the proguction medium had stimulating effect on P(3HB-co-3HV) accumulation, especially in the manganese. deficient medium. The optimum temperature for P(3HB-co-3HV) production was 27$^{\circ}C$ and the optimum initial pH was 7.0. Under the optimum conditions, 1.82g/l of P(3HB-co-3HV) and 3.00g/l of dry biomass were produced after 36 hour cultivation, and the P(3HB-co-3HV) yield and HV% were 60.60% (w/w), 15.92%, respectively.

• Molecules and Cells
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• 제42권11호
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• pp.773-782
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• 2019

Cellular senescence is an irreversible form of cell cycle arrest. Senescent cells have a unique gene expression profile that is frequently accompanied by senescence-associated heterochromatic foci (SAHFs). Protein kinase CK2 (CK2) downregulation can induce trimethylation of histone H3 Lys 9 (H3K9me3) and SAHFs formation by activating SUV39h1. Here, we present evidence that the PI3K-AKT-mTOR-reactive oxygen species-p53 pathway is necessary for CK2 downregulation-mediated H3K9me3 and SAHFs formation. CK2 downregulation promotes SUV39h1 stability by inhibiting its proteasomal degradation in a p53-dependent manner. Moreover, the dephosphorylation status of Ser 392 on p53, a possible CK2 target site, enhances the nuclear import and subsequent stabilization of SUV39h1 by inhibiting the interactions between p53, MDM2, and SUV39h1. Furthermore, $p21^{Cip1/WAF1}$ is required for CK2 downregulation-mediated H3K9me3, and dephosphorylation of Ser 392 on p53 is important for efficient transcription of $p21^{Cip1/WAF}$. Taken together, these results suggest that CK2 downregulation induces dephosphorylation of Ser 392 on p53, which subsequently increases the stability of SUV39h1 and the expression of $p21^{Cip1/WAF1}$, leading to H3K9me3 and SAHFs formation.

• Animal cells and systems
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• 제16권3호
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• pp.173-182
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• 2012

The p53 protein plays a pivotal role in tumor suppression. The cellular level of p53 is normally kept low by proteasome-mediated degradation, allowing cell cycle progression and cell proliferation. Under stress conditions, such as DNA damage, p53 is stabilized and activated through various post-translational modifications of itself as well as of its regulatory proteins for induction of the downstream genes responsible for cell cycle arrest, DNA repair, and apoptosis. Therefore, the level of p53 should be tightly regulated for normal cell growth and for prevention of the accumulation of mutations in DNA under stress conditions, which otherwise would lead to tumorigenesis. Since the discovery of Mdm2, a critical ubiquitin E3 ligase that destabilizes p53 in mammalian cells, nearly 20 different E3 ligases have been identified and shown to function in the control of stability, nuclear export, translocation to chromatin or nuclear foci, and oligomerization of p53. So far, a large number of excellent reviews have been published on the control of p53 function in various aspects. Therefore, this review will focus only on mammalian ubiquitin E3 ligases that mediate proteasome-dependent degradation of p53.

• 미생물학회지
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• 제52권4호
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• pp.455-462
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• 2016

Pseudomonas aeruginosa P-5 균주는 홀수개의 탄소수를 갖는 지방산으로부터 3-hydroxyvalerate (3HV)와 medium-chain-length (MCL) 3-hydroxyalkanoates (3HAs) 단위체로 구성된 popolyhydroxyalkanoate (PHA) 공중합체를 생산하는 특이한 성질을 갖고 있다. 이 균주가 갖고 있는 2개의 MCL-PHA synthases ($PhaC1_{P-5}$와 $PhaC2_{P-5}$)의 탄소길이에 따른 기질특이성을 비교하기 위하여 각각의 유전자를 PHA 생합성능이 결여된 돌연변이주 Pseudomonas putida GPp104에 도입하고 발현시킨 결과, $PhaC2_{P-5}$는 3HV와 MCL 3HAs로 이루어진 공중합체를 생산하지만 $PhaC1_{P-5}$는 단지 MCL 3HAs로 구성된 공중합체를 생산하였다. 이는 $PhaC2_{P-5}$가 $PhaC1_{P-5}$과는 달리 보다 짧은 탄소길이의 3-hydroxyvaleryl Co-A를 기질로 인지하여 합성반응에 이용할 수 있음을 보여주는 것이다. 또한 $PhaC2_{P-5}$의 효소활성 및 기질특이성의 변화를 유도하기 위하여 위치지정 돌연변이생성을 수행하고 P. putida GPp104과 다른 PHA 생합성능 결여 돌연변이주인 Ralstonia eutropha $PHB^-4$에서 발현시킨 결과, $PhaC2_{P-5}$ 내 두 개 아미노산의 치환(Ser326Thr과 Gln482Lys)이 공중합체의 3HV 함량을 크게 증진시키는 효과를 보였다. 두 개 아미노산이 모두 치환된 $PhaC2_{P-5}$ 유전자($phaC2_{P-5}QKST$)를 갖는 P. putida GPp104를 nonanoic acid가 탄소원으로 함유된 배지에서 배양하였을 때, 모균주에 비해 공중합체 함량과 공중합체 내 3HV 함량이 각각 2.5배 및 3.5배 증가하였다. 따라서 $phaC2_{P-5}QKST$를 포함하는 재조합 균주는 개량된 물성의 신규PHAs 생산에 유용할 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제26권5호
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• pp.795-801
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• 2005

New PPV derivatives which contain electron-withdrawing trifluoromethyl ($CF_3$) group, poly[2-(2-ethylhexyloxy)-5-(4-trifluoro methylphenyl)-1,4-phenylenevinylene] (EH$CF_3$P-PPV), and poly[2-(2-ethylhexyloxy)-5-(3,5-bis(trifluoromethyl)-phenyl)-1,4-phenylenevinylene] (EHB$CF_3$P-PPV), have been synthesized by GILCH polymerization. As the result of the introduction of the electron-withdrawing $CF_3$ group to the phenyl substituent, the LUMO and HOMO energy levels of EH$CF_3$P-PPV (2.8, 5.1 eV) and EHB$CF_3$P-PPV (3.0, 5.3 eV) were lower than those of known poly[2-(2-ethylhexyloxy)-5-phenyl-1,4-phenylenevinylene] (EHP-PPV) (2.6, 4.9 eV). These polymers have been used as the electroluminescent (EL) layers in double layer lightemitting diodes (LEDs) (ITO/PEDOT/polymer/Al). EH$CF_3$P-PPV, and EHB$CF_3$P-PPV show maximum photoluminescence (PL) peaks at ${\lambda}_{max}$ = 550, 539 nm, and maximum EL peak at ${\lambda}_{max}$ = 545, 540 nm, respectively. The current-voltage-luminance (I-V-L) characteristics of the polymers show that turn-on voltages of EH$CF_3$P-PPV and EHB$CF_3$P-PPV are around 4.0 and 3.5 V, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1440-1443
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• 2001

Forty eight $Duroc{\times}Yorkshire{\times}Landrace$ pigs ($15.2{\pm}0.3kg$ average initial BW) were used conducted to evaluate the effects dietary phytase (Phytezyme, WOOJIN, Co. Ltd) supplementation on the growth performance and nutrient digestibility in growing pigs. There were three pigs per pen and four pens per treatment. Treatments were 1) Con (corn-wheat-SBM), 2) PE0.1 (low-P iet+0.1% Phytezyme), 3) PE0.2 (Iow-P diet+0.2% Phytezyme), 4) PE0.3 (low-P diet+0.3% Phytezyme). During d 0 to 28, average daily gain was not significantly different among the treatments. Pigs fed PE0.3 diet significantly decreased (p<0.05) their average daily feed intake compared to pigs fed Con diet. Also, gain/feed in pigs fed PE0.1 and PE0.3 diet was improved (p<0.05) compared to pigs fed Con and PE0.2 diet (p<0.05). For d 28 to 56, pigs fed PE0.2 diet grew significantly faster (p<0.05) than pigs fed Con and PE0.1 diet. Gain/feed was greater (p<0.05) for PE0.2 and PE0.3 treatments than for Con. For overall period, average daily gain was increased (P<0.05) by the addition of 0.2% Phytezyme compared with Con. Gain/feed was significantly improved (p<0.05) by supplementation of PE0.3. Pigs fed PE0.2 showed increased DM and N digestibilities compared to pigs fed other treatments. Supplemented diets PE0.2 and PE0.3 improved (p<0.05) the apparent digestibility of Ca and P compared to other treatments. In conclusion, the results obtained from these feeding trials suggest that the Phytezyme supplementation of diets for growing-finishing pigs had improved growth performance and nutrient availability.