• 대한수학회보
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• 제56권1호
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• pp.57-71
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• 2019

Let R be an associative ring with identity, M a t.u.p. monoid with only one unit and ${\omega}:M{\rightarrow}End(R)$ a monoid homomorphism. Let R be a reversible, M-compatible ring and ${\alpha}=a_1g_1+{\cdots}+a_ng_n$ a non-zero element in skew monoid ring $R{\ast}M$. It is proved that if there exists a non-zero element ${\beta}=b_1h_1+{\cdots}+b_mh_m$ in $R{\ast}M$ with ${\alpha}{\beta}=c$ is a constant, then there exist $1{\leq}i_0{\leq}n$, $1{\leq}j_0{\leq}m$ such that $g_{i_0}=e=h_{j_0}$ and $a_{i_0}b_{j_0}=c$ and there exist elements a, $0{\neq}r$ in R with ${\alpha}r=ca$. As a consequence, it is proved that ${\alpha}{\in}R*M$ is unit if and only if there exists $1{\leq}i_0{\leq}n$ such that $g_{i_0}=e$, $a_{i_0}$ is unit and aj is nilpotent for each $j{\neq}i_0$, where R is a reversible or right duo ring. Furthermore, we determine the relation between clean and nil clean elements of R and those elements in skew monoid ring $R{\ast}M$, where R is a reversible or right duo ring.

• 한국환경성돌연변이발암원학회지
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• 제22권3호
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• pp.169-174
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• 2002

Resveratrol is known to have potent cancer chemopreventive activity against tumorigenesis caused by 7,12-dimetylbenz［$\alpha$］anthracene(DMBA) which is known to be oxidized to reactive products by cytochrome P450 1B1 (CYP1B1). The effects of resveratrol on the activity of recombinant human P450 1 family enzymes, expressed in Escherichia coli membranes with human NADPH-P450 reductase, were determined by measuring alkoxyresorufin O-dealkylation activity, e.g., ethoxyresorufin O-deethylation (EROD) CYP1A1, methoxyresorufin O-demethylation (MROD), CYP1A2, benzyloxyresorufin-O-debenzylation (BROD), CTP1B1. Resveratrol inhibited CYP1B1 and CYP1A1 activities in a dose-dependent manner with $IC_{50}$/ values of 59 and 10$\mu$M for EROD activity and 1.8 and 30$\mu$M for BROD activity, respectively. Resveratrol had only weak inhibitory effect on CYP1A2 activity ($IC_{50}$/ values of 0.44 mM for EROD and ＞2 mM for MROD). Furthermore, resveratrol did not affect NADPH-P450 reductase activity significantly. Resveratrol inhibited the CYP1B1-dependent EROD activity with a $K_{i}$ of 28 $\mu$M in a non-competitive type manner. these results suggest that resveratrol-derived inhibited of CYP1B1 and CYP1A1 activities may contribute to the suppression of DMBA inducible tumorigenesis observed in extrahepatic tissues.s.

• BMB Reports
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• 제32권3호
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• pp.226-231
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• 1999

In vitro effects of acetone on cytochrome P450 (P450)-dependent benzo(a)pyrene (B(a)P) hydroxylation supported by cumene hydroperoxide (CuOOH) or NADPH/$O_2 $ systems were studied using 3-methylcholanthrene-pretreated rat liver microsomes. The maximal rate of B(a)P hydroxylation at constant concentration ($80\;{\mu}M)$ of the substrate was observed in the presence of $30\;{\mu}M$ CuOOH. However, at concentrations higher than $30\;{\mu}M$ CuOOH the hydroxylation rates were rapidly decreased. In contrast to CuOOH, at a concentration of $200\;{\mu}M$ NADPH, B(a)P hydroxylation rate reached a plateau. At concentrations higher than $200\;{\mu}M$ NADPH, the rates of substrate hydroxylation were maintained at the maximal rate with no inhibition. Acetone at 1% (v/v) enhanced both CuOOH- and NADPH/$O_2$-supported B(a)P hydroxylation at the optimal concentrations of the cofactors. At concentrations higher than 1% (v/v) acetone, substrate hydroxylation was sterero specific under the support of these two cofactors; it was strongly enhanced with $30\;{\mu}M$ CuOOH, but rather inhibited in the $200\;{\mu}M$> NADPH/$0_2 $ system. The lipid peroxidation rate induced during CuOOH-supported P450-dependent B(a)P hydroxylation was increased as CuOOH concentrations were increased. Acetone in the concentration range of 2.5~7.5%(v/v) inhibited lipid peroxidation during CuOOH supported B(a)P hydroxylation. The finding that CuOOH-supported B(a)P hydroxylation is greatly enhanced by acetone suggests that acetone may contribute more to the activation of oxygen (for the insertion of oxygen into the substrate) in the presence of CuOOH than with NADPH/$O_2$. Acetone may also contribute to the partial inhibition of destruction of microsomal membranes by lipid peroxidation.

• 한국식품조리과학회지
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• 제27권1호
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• pp.55-62
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• 2011

The aim of this study was to investigate the effects of UV-B irradiation on the physicochemical characteristics of oyster mushrooms (Pleurotus ostreatus). Vitamin $D_2$ concentration, weight loss rate, color value, total plate counts and consumer acceptability of irradiated oyster mushrooms were measured. UV-B irradiation at doses of $0\;kj/m^2$, $20\;kj/m^2$ and $40\;kj/m^2$, significantly increased the vitamin $D_2$ concentrations from $0\;{\mu}g/g$ dry weight (control) to $85.87\;{\mu}g/g$ dw and $116.28\;{\mu}g/g$ dw, respectively, at 5% level. Rate of weight loss was also significantly increased from 0% (control) to 2.21% and 4.31% at $20\;kj/m^2$ and $40\;kj/m^2$ UV-B irradiation, respectively, at 5% level. Although there was no significant difference between the UV-B irradiated groups, total plate counts were significantly decreased from $1.0{\times}10^5$ (control) to $9.4{\times}10^3$ and $1.9{\times}10^3$at $20\;kj/m^2$ and $40\;kj/m^2$ of UV-B irradiation, respectively, at 5% level. There was no significant difference in L values and consumer acceptability between the groups. Therefore, UV-B irradiated oyster mushrooms could be used as health promoting ingredients for many foods.

• 생명과학회지
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• 제25권9호
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• pp.1043-1050
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• 2015

신경과흥분은 신경세포의 수지돌기 말단부에 있는 흥분성 수용체에 대한 과도한 자극에 의해서 신경세포가 손상을 받는 현상으로 transcription factor의 발현을 유도하여 통증을 유발하는 자극, 학습, 발작, 흥분, 신경변성, 저산소성 국소빈혈, 뇌신경손상, 신경절제, 약제내성 등의 원인이 된다. 신경과흥분은 정상농도 이상의 NMDA에 의해서도 유발되는데 본 논문에서는 mouse의 복강으로 과량의 NMDA를 투여하여 소뇌에서 RT-PCR 방법으로 Inducible transcription factors (Egr-1, c-jun, JunB, FosB) mRNAs의 상대적 발현량을 비교하였다. NMDA를 투여한 군에서 inducible transcription factors (Egr-1, C-Jun, JunB, FosB)가 투여량과 시간의 경과에 따라 다양한 발현의 변화를 보였으며, NMDA투여 후 일정한 시간에서 투여한 양에 대한 변화는 체중 g 당 5 μg의 NMDA투여한 경우에 현저한 변화가 나타났다. 조사한 transcription factor 중에서 JunB의 발현 변화가 다른 transcription factor보다 두드러지게 나타났다. NMDA 투여량이 일정할 때 투여 후 경과 시간에 따른 발현양상은 투여 후 24시간이 경과한 후에 발현의 변화가 두드러지게 증가하는 경향을 나타내었고 대부분 이 48시간 경과 후 발현이 최고치에 도달하였다. 이러한 결과는 과흥분이 유도된 소뇌에서의 유전자 발현의 변화를 2D-gel 또는 microarray와 같은 방법을 이용하여 세포 내의 전체 단백질 혹은 유전자의 변화를 관찰함으로써 NMDA 수용체의 과흥분에 의한 뇌세포의 사멸에 관련된 기전을 밝힐 수 있는 좋은 자료가 될 수 있을 것으로 기대된다.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.362-367
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• 2009

In recombinant strains, many proteins and enzymes are expressed as inactive and insoluble inclusion bodies. For soluble expression of an active form of StyB, an NADH-flavin oxidoreductase, several recombinant Escherichia coli strains were developed and tested. Among them, strain BL21(DE3)pLysS effectively produced an active and soluble form of StyB as about 9% of the total protein content, when cultivated at $20^{\circ}C$ with 0.5 mM IPTG. The solubly expressed StyB has the highest oxidoreductase activity at pH 6.5-7.5 and $37^{\circ}C$. Substrate dependence profiles of the StyB-catalyzed reaction showed that the maximum specific activity($V_m$) and half saturation constant($K_m$) were $1,867{\pm}148\;U/mg$ protein and $51.6{\pm}11{\mu}M$ for NADH, and $1,274{\pm}34\;U/mg$ protein and $8.2{\pm}1.2{\mu}M$ for FAD, respectively. This indicates that solubly produced StyB has 6- to 9-fold higher oxidoreductase activities than the in vitro refolded StyB from inclusion bodies.

• 한국통신학회논문지
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• 제39C권2호
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• pp.151-163
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• 2014

위치기반 서비스, 상황인지 서비스 등 다양한 응용 서비스들은 최근 개발되고 있는 웨어러블 디바이스와의 상호작용을 통해 착용자에게 다양한 서비스를 제공한다. 하지만 기존의 웨어러블 디바이스의 경우 서비스 사용을 위한 사용자의 의도적인 조작이 필요한 한계가 있어 단말 조작이 서툰 사용자들의 경우 서비스를 이용하는데 제약이 있다. 따라서 착용자가 누구든지 간에 응용 서비스를 이용할 수 있도록 사용자의 의도적인 설정과정 없이 이웃하는 단말들 간의 자율적인 통신이 필요하다. 본 논문에서는 블루투스 저에너지(BLE) 프로토콜 기반의 이동 단말의 실내 위치인지를 위한 B-LIDx 프로토콜과 이웃하는 단말들 간의 무설정 기회기반 직접 사물통신을 지원하는 B-PniP을 제안한다. 또한 실제 환경에서 이동 단말의 위치를 인지하는데 걸리는 시간과 B-PniP 서비스 사례별 서비스 소요 시간 측정을 통해 제안 프로토콜의 성능을 평가하였다.

• 한국식품과학회지
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• 제29권3호
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• pp.571-575
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• 1997

본 연구에서는 당근을 원료로 하여 Bifidobacterium을 배양하여 발효하며 Bifidobacterium의 배양특성을 살펴보았다. Bifidobacterium의 다양한 균주를 $10^6\;CFU/mL$ 수준으로 접종하여 배양하였을 때 B. longum, B. adolescentis, B. infantis 균주들은 $10^8\;CFU/mL$ 이상으로 자랐고 B. bifidum 균주들은 약간 성장이 저조하여 $10^8\;CFU/mL$ 이하 수준으로 자랐다. 당근 이외의 다른 원료로서 포도, 사과, 오렌지, 복숭아, 배추, 오이 등에 배양하였을 때 복숭아, 오렌지 등에서는 배양이 양호하였으나 포도에서는 Bifidobacterium의 성장이 일어나지 않았다. L. acidophilus와 혼합 배양시 Bifidobacterium 단독 배양시보다 균의 증식이 저하되었고 배양 24시간 후부터 Bifidobacterium의 사멸이 현저하게 일어났다. Bifidobacterium 배양에 의하여 당근의 산미가 증가되며 관능성이 개선되는 것으로 나타났다. 따라서 Bifidobacterium을 이용한 당근 발효식품 개발은 Bifidobacterium균주의 증식에 의한 기능성 증가와 당근의 관능성 개선에 도움이 될 것으로 생각된다.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2498-2504
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• 2009

본 논문에서는 8.2MHz 대역의 국내 미약 전계 강도 무선기기의 출력 제한치를 다른 외국의 기준치와 비교하였다. 이를 통해 국내의 규정이 미국이나 유럽에 비해 낮음을 대략 10-20dB 정도 낮음을 확인하였고, 이를 검증하기 위해 8.2MHz EAS 시스템의 출력을 측정하였다. 측정 결과, 전계 강도값이 각각 $70.6dB{\mu}V/m$와 $68.3dB{\mu}V/m$로 측정되었는데, 이러한 값은 국내의 현재기준인 $59.8dB{\mu}V/m$를 초과하는 값임을 확인하였다. 따라서 8.2MHz 대역의 국내기준의 사향 검토가 필요하다 사료된다.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.812-821
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• 2007

The ecosystems of certain abandoned mines contain arsenic-resistant bacteria capable of performing detoxification when an ars gene is present in the bacterial genome. The ars gene has already been isolated from Pseudomonas putida and identified as a member of the membrane transport regulatory deoxyribonucleic acid family. The arsenite-oxidizing bacterial strains isolated in the present study were found to grow in the presence of 66.7 mM sodium arsenate($V;\;Na_2HAsO_4{\cdot}7H_2O$), yet experienced inhibited growth when the sodium arsenite($III;\;NaAsO_2$) concentration was higher than 26 mM. Batch experiment results showed that Pseudomonas putida strain OS-5 completely oxidized 1 mM of As(III) to As(V) within 35 h. An arsB gene encoding a membrane transport regulatory protein was observed in arsenite-oxidizing Pseudomonas putida strain OS-5, whereas arsB, arsH, and arrA were detected in strain OS-19, arsD and arsB were isolated from strain RW-18, and arsR, arsD, and arsB were found in E. coli strain OS-80. The leader gene of arsR, -arsD, was observed in a weak acid position. Thus, for bacteria exposed to weak acidity, the ars system may cause changes to the ecosystems of As-contaminated mines. Accordingly, the present results suggest that arsR, arsD, arsAB, arsA, arsB, arsC, arsH, arrA, arrB, aoxA, aoxB, aoxC, aoxD, aroA, and aroB may be useful for arsenite-oxidizing bacteria in abandoned arsenic-contaminated mines.