• 한국자원식물학회지
• /
• 제23권5호
• /
• pp.445-450
• /
• 2010

본 연구에서는 개머루덩굴 95% 에탄올추출물의 항산화 효과를 조사하였다. Pyrogallol의 억제율을 100%로 기준하였을 때, DPPH 라디칼을 50% 억제시키는데 필요한 개머루덩굴 추출물의 농도는 0.42 mg/mL이었다. 총항산화 활성은 ABTS 라디칼에 대한 항산화능으로 측정하였다. 개머루덩굴 추출물 0.1 및 1 mg/mL의 총항산화능은 각각 0.65 및 3.71 mM Trolox와 동등한 수준이었다. 개머루덩굴 추출물 5 및 $100\;{\mu}g/mL$의 peroxyl radical 소거능은 각각 22.75 및 $131.25\;{\mu}M$ gallic acid와 동등한 수준이었다. 개머루덩굴 추출물 0.1 및 1 mg/mL의 superoxide 소거능은 각각 27.7 및 56.0%이었다. 개머루덩굴 추출물 0.5 및 2 mg/mL의 총페놀 함량은 각각 0.55 및 2.06 mM gallic acid와 동등한 수준이었다. 또한, HepG2 세포주를 이용한 세포배양에서 개머루덩굴 추출물 0.1 mg/mL 농도의 첨가는 0.2 및 0.5 mM tert-butyl hydroperoxide로 유도된 세포독성을 각각 36.2 및 23.3% 감소시켰다. 따라서, 본 연구 결과들은 개머루덩굴 추출물의 강력한 항산화 효과와 세포독성 억제 효과를 나타내며, 이러한 효능은 적어도 자유라디칼의 산화 억제와 높은 총페놀 함량에 기인하는 것으로 사료된다.

• 한국산학기술학회논문지
• /
• 제16권4호
• /
• pp.2924-2932
• /
• 2015

본 연구는 초등학교, 중학교 및 고등학교의 급수설비 사용수량의 분석 통해 급수량 산출자료를 추정하여 학교시설 급수시스템의 적정 급수계획에 필요한 기초자료를 얻고자 하였다. 이를 위하여, 강원지역 6개 도시에 소재하는 초 중 고등학교 54개 학교를 대상으로 5년간의 급수설비 사용수량을 분석하였다, 분석결과, 1) 월평균 사용수량의 평균은 $600.7(m^3/mon)$이었으며, 초등학교와 중학교가 $484.2(m^3/mon)$, 고등학교가 $833.8(m^3/mon)$로 분석 되었다. 2) 학급당 월평균 사용수량의 평균은 $27.0(m^3/mon/class)$이었으며, 초등학교와 중학교가 $24.4(m^3/mon/class)$, 고등학교가 $32.(m^3/mon/class)$로 분석 되었다. 3) 1인1일 평균 사용수량의 평균은 55.8(l/c/d)이었으며, 초등학교와 중학교가 54.4(l/c/d), 고등학교가 58.6(l/c/d)로 분석 되었다.

• 천문학회보
• /
• 제41권2호
• /
• pp.54.3-55
• /
• 2016

We model the spectral energy distribution (SED) of the Class 0 protostar L1527 IRS using a dust continuum radiative transfer code RADMC-3D to study the initial condition of gravitational collapse. To constrain the envelope structure, we use the data obtained by Herschel /PACS, which covers the far-infrared regime ($55-190{\mu}m$) where the SED of L1527 IRS peaks. According to our modeling, a more flattened density profile fits the far-infrared SED of L1527 IRS better than the density profile of a rotating and infalling envelope. Thus, we employ the density structure of a Bonnor-Ebert sphere, which consists of the inner flat-topped and the outer power-law regions and is often used for describing the density structure of the youngest sources in the low mass star formation process. A Bonnor-Ebert sphere fits very well the observed SED at ${\lambda}$ > $10{\mu}m$, suggesting that L1527 IRS might collapse from an unstable Bonnor-Ebert sphere rather than a singular isothermal sphere.

• Journal of Applied Biological Chemistry
• /
• 제50권3호
• /
• pp.115-119
• /
• 2007

To discover the sources with antioxidant and tyrosinase inhibitory activities in Korean traditional medicines, 10 extract of medicinal plants were screened for their potential to scavenge stable 1,1-diphenyl-2-picryhydrazyl (DPPH) free radical, inhibit hydroxyl radical (${\cdot}OH$), total phenolic content, and inhibition of tyrosinase. The potency of DPPH radical scavenging activity was shown in the extract of Ulmus davidiana var. japonica Nakai that has a greater effect with $IC_{50}$ values of $6.49{\pm}5.43{\mu}g/mL$, than BHA ($IC_{50}=20.99{\pm}0.74{\mu}g/mL$), L-ascorbic acid $(IC_{50}=20.59{\pm}1.06{\mu}g/mL),\;and\;{\alpha}-tocopherol\;(IC_{50}=25.55{\pm}0.26{\mu}g/mL)$ as a positive control. The ${\cdot}OH$ scavenging activities were observed in the plants tested. Acanthopanax senticosus, Cirsium setiders, U. davidiana exhibited scavenging activity of more than 60% at $500{\mu}g/mL$. The scavenging activity(%) of BHA and a-tocopherol were 64.32 and 55.87% at $500{\mu}g/mL$, respectively. The total phenolic content was determined, in order to assess its effect on the extract's antioxidant activity. The total phenoic content of $33.37{\pm}0.52mg/g$ was conformed by methanolic extract of U. davidiana. The U. davidiana and Morus bombycis exhibited tyrosinase inhibitory activity with a $34.28{\pm}1.32\;and\;75.57{\pm}1.10%$, respectively. In particular, M. bombycis has stronger tyrosinase inhibitory activity than albutin with $36.48{\pm}3.56%$ as a positive control. This work showed that the inhibitory abilities of Korean medicinal plants, such as U. davidiana and M. bombycis, on DPPH free radical, inhibit hydroxyl radical (${\cdot}OH$), and inhibition of tyrosinase and total phenolic content, can be useful in the prevention and treatment of free radical-relate disease. Investigations into further isolation of inhibitory principles of U. davidiana and M. bombycis are now in progress.

• 대한수학회지
• /
• 제55권3호
• /
• pp.671-694
• /
• 2018

In this paper, we investigate the weighted vector-valued bounds for a class of multilinear singular integral operators, and its commutators, from $L^{p_1}(l^{q_1};\;{\mathbb{R}}^n,\;w_1){\times}{\cdots}{\times}L^{p_m}(l^{q_m};\;{\mathbb{R}}^n,\;w_m)$ to $L^p(l^q;\;{\mathbb{R}}^n,\;{\nu}_{\vec{w}})$, with $p_1,{\cdots},p_m$, $q_1,{\cdots},q_m{\in}(1,\;{\infty})$, $1/p=1/p_1+{\cdots}+1/p_m$, $1/q=1/q_1+{\cdots}+1/q_m$ and ${\vec{w}}=(w_1,{\cdots},w_m)$ a multiple $A_{\vec{P}}$ weights. Our argument also leads to the weighted weak type endpoint estimates for the commutators. As applications, we obtain some new weighted estimates for the $Calder{\acute{o}}n$ commutator.

• 월간양계
• /
• 통권14호
• /
• pp.53-55
• /
• 1970

• 한국식품과학회지
• /
• 제31권6호
• /
• pp.1415-1420
• /
• 1999

우리나라 찰옥수수의 품질을 향상시키는 성분육종의 기초자료를 제공하고자, 310개 $F_1$의 지방산 조성과 항산화 활성, 페놀화합물, tocopherols, carotenoids의 함량을 분석한 결과는 다음과 같다. Palmitic acid와 stearic acid, linoleic acid, 불포화지방산은 각각 $14.6{\pm}2.5%,\;2.5{\pm}1.0%,\;24.8{\pm}4.2%,\;55.6{\pm}5.4%,\;81.8{\pm}3.1%$였고, 항산화 활성과 페놀화합물, tocopherols, carotenoids의 함량은 각각 $22.8{\pm}5.9%,\;36.2{\pm}11.5\;{\mu}g/mL,\;120.3{\pm}27.7\;{\mu}g/mL,\;0.4{\pm}0.6\;{\mu}g/mL$였다. Linoleic acid와 oleic acid 간에는 고도의 부의 상관관계가 있었다. 항산화활성은 페놀화합물과 tocopherols 함량과는 고도의 상관관계가 있었으나, carotenoids의 함량과는 유의성이 없었다

• 대한기계학회논문집A
• /
• 제24권9호
• /
• pp.2326-2333
• /
• 2000

Creep tests for type 316L(N) stainless steel were carried out using constant-load creep machines at 55$0^{\circ}C$, 575$^{\circ}C$ and $600^{\circ}C$. Material constants necessary to predict creep rupture time were obtained from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. The log-log plot of M-G relationship between the rupture time($t_r$,) and the minimum creep rate ($ $\varepsilon$ _m$) was dependent on test temperatures. The slope of m was 1,05 at 55$0^{\circ}C$ and m was 1.30 at $600^{\circ}C$. On the other hand, the log-log plot of modified M-G relationship between $t_r/$\varepsilon$_r$, and $ $\varepsilon$ _m$ was independent on stresses and temperatures. That is, the slope of m＇ was approximately 1.35 in all the data. Thus, modified M-G relationship for creep life prediction could be utilized more reasonably than that of M-G relationship for type 316L(N) stainless steel. It was analyzed that the constant slopes regardless of temperatures or applied stresses in the modified relationship were due to an intergranular fracture grown by wedge-type cavities.

• 대한기계학회논문집
• /
• 제19권1호
• /
• pp.87-98
• /
• 1995

When the crack in orthotropic material is propagating under dynamic model I load, influences of anisotropic property ratio $E_{L}$/ $E_{T}$ on stress and displacement around propagating crack tip are studied in this paper. When M<0.55 and .alpha.=90.deg.(.alpha.; the angle of fiber direction with crack propagating direction, M; crack propagation velocity/shear stress wave velocity), the influence of $E_{L}$/ $E_{T}$ on stress .sigma.$_{x}$, .sigma.$_{y}$, .tau.$_{xy}$ and .sigma.$_{\theta}$ is the greast on .sigma.$_{y}$. Except M<0.55 and .alpha.=90.deg., it is the greast on .sigma.$_{x}$ in any situation. Increasing $E_{L}$/ $E_{T}$, stress components are increased or decreased. When maximum stress is based, the stress .sigma.$_{x}$(.alpha.=90.deg.), .sigma.$_{y}$(.alpha.=0.deg.) and .tau.$_{xy}$ (.alpha.=90.deg.) are decreased with increment of $E_{L}$/ $E_{T}$ in M=0. any stresses except .sigma.$_{*}$x/(.alpha.=0.deg.) are decreased with increment of $E_{L}$/ $E_{T}$ in M=0.9. When .alpha.=90.deg., the influence of $E_{L}$/ $E_{T}$ on displacement U and V is V>U in any velocities of crack propagation, when .alpha.=0.deg., it is VU in M>0.75 and when $E_{L}$/ $E_{T}$ is increased, U and V are decreased in any conditions.sed in any conditions.tions.tions.tions.