• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.1
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• pp.1-8
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• 2013

In this work, comparative study on antioxidative activities of extracts from Glycyrrhiza uralensis (G. uralensis) produced in Korea and in China and Glycyrrhiza glabra (G. glabra) produced in Uzbekistan was conducted. Among three origins, 50% ethanol extracts (21.15 ${\mu}g/mL$), ethyl acetate fraction (29.15 ${\mu}g/mL$) and aglycone fraction (3.26 ${\mu}g/mL$) of G. uralensis from Korea showed the higher free radical (1,1-phenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) than extracts from other origins. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of extracts from three origins on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using luminol-dependent chemiluminescence assay 50% ethanol extract (1.00 ${\mu}g/mL$) and ethyl acetate fraction (0.34 ${\mu}g/mL$) of G. uralensis from China showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of G. uralensis and G. glabra extracts on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. 50% ethanol extract and aglycone fraction of G. uralensis and G. glabra extracts from three origins showed cellular protective effects in a concentration dependent manner (5 ~ 50 ${\mu}g/mL$). Aglycone fraction of G. uralensis from Korea (${\tau}_{50}$ = 847.4 min)especially showed cellular protective effects four times higher than that from China (${\tau}_{50}$ = 194.3 min). These results indicate that G. uralensis and G. glabra extracts, which have been used as whitening agent, could be applicable to functional cosmetic ingredient as a natural antioxidant. Judging from the prominent cellular protecitve effects, it is concluded that G. uralensis and G. glabra extracts can protect the skin from $^1O_2$ and various ROS induced by UV.

• Communications of the Korean Mathematical Society
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• v.28 no.2
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• pp.303-317
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• 2013

In present paper, we obtain functions $R_t(c,{\nu},a,b)$ and $R_t(c,-{\mu},a,b)$ by using generalized hypergeometric function. A recurrence relation, integral representation of the generalized hypergeometric function $_2R_1(a,b;c;{\tau};z)$ and some special cases have also been discussed.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1461-1466
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• 2010

aSuppose that (M, g) is a complete Riemannian manifold with Ricci curvature bounded below by -K < 0 and (N, $\bar{b}$) is a complete Riemannian manifold with sectional curvature bounded above by a constant $\mu$ > 0. Let u : $M{\times}[0,\;{\infty}]{\rightarrow}B_{\tau}(p)$ is a heat equation for harmonic map. We estimate the energy density of u.

• Bulletin of the Korean Mathematical Society
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• v.50 no.4
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• pp.1109-1126
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• 2013

Let $\mathbb{M}^3_q(c)$ denote the 3-dimensional space form of index $q=0,1$, and constant curvature $c{\neq}0$. A curve ${\alpha}$ immersed in $\mathbb{M}^3_q(c)$ is said to be a Bertrand curve if there exists another curve ${\beta}$ and a one-to-one correspondence between ${\alpha}$ and ${\beta}$ such that both curves have common principal normal geodesics at corresponding points. We obtain characterizations for both the cases of non-null curves and null curves. For non-null curves our theorem formally agrees with the classical one: non-null Bertrand curves in $\mathbb{M}^3_q(c)$ correspond with curves for which there exist two constants ${\lambda}{\neq}0$ and ${\mu}$ such that ${\lambda}{\kappa}+{\mu}{\tau}=1$, where ${\kappa}$ and ${\tau}$ stand for the curvature and torsion of the curve. As a consequence, non-null helices in $\mathbb{M}^3_q(c)$ are the only twisted curves in $\mathbb{M}^3_q(c)$ having infinite non-null Bertrand conjugate curves. In the case of null curves in the 3-dimensional Lorentzian space forms, we show that a null curve is a Bertrand curve if and only if it has non-zero constant second Frenet curvature. In the particular case where null curves are parametrized by the pseudo-arc length parameter, null helices are the only null Bertrand curves.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.160-160
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• 2010

테라헤르츠 소스로 저온 InGaAs를 대체하기 위해 저온에서 성장한 $In_{0.64}Al_{0.36}Sb$의 성장 온도에 따른 광학적 photoluminescence (PL)과 time-resolved PL (TRPL) 측정을 이용하여 분석하였다. 또한 Be 도핑 농도에 따른 p형 $In_{0.64}Al_{0.36}Sb$의 PL과 TRPL 특성을 undoped $In_{0.64}Al_{0.36}Sb$와 Si-doped $In_{0.64}Al_{0.36}Sb$ 결과와 비교 분석하였다. 본 연구에 사용한 시료는 분자선 엑피탁시 (molecular beam epitaxy)법으로 GaAs 기판 위에 $In_{0.64}Al_{0.36}Sb$을 다양한 성장온도에서 ${\sim}3.7\;{\mu}m$두께 성장하였다. $In_{0.64}Al_{0.36}Sb$의 성장온도는 $400^{\circ}C$ 에서 $460^{\circ}C$까지 변화시키며 성장하였으며, Si과 Be 도핑한 $In_{0.64}Al_{0.36}Sb$ 시료는 약 $420^{\circ}C$에서 성장하였다. 모든 시료의 PL 피크는 ~1450 nm 근처에서 나타나며 단파장 영역에 shoulder 피크가 나타났다. 그러나 가장 낮은 온도 $400^{\circ}C$에서 성장한 시료는 1400 nm에서 1600 nm에 걸쳐 매우 넓은 피크가 측정되었다. PL 세기는 $450^{\circ}C$ 에서 성장한 시료가 가장 강하게 나타났으며, $435^{\circ}C$에서 성장한 시료의 PL 세기가 가장 약하게 나타났다. 방출파장에 따른 PL 소멸곡선을 측정하였으며 double exponential function을 이용하여 운반자 수명시간을 계산하였다. 운반자 수명시간은 빠른 소멸성분 $\tau_1$과 느린 소멸성분 $\tau_2$가 존재하고 빠른 성분 $\tau_1$의 PL 진폭이 약 80%로 느린 성분 $\tau_2$보다 우세하게 나타났다. 각 PL 피크에서의 운반자 수명시간 $\tau_1$은 ~1 ns로 성장온도에 따른 변화는 관찰되지 않았다. 또한 방출파장이 1400 nm에서 1480 nm까지 PL 피크 근처에서 운반자 수명시간은 거의 일정하게 나타났다. Be-doped 시료의 PL 피크는 1236 nm에서 나타나며, Si-doped 시료는 1288 nm, undoped 시료는 1430 nm에서 PL 피크가 측정되었다. PL 피크에서 PL 소멸곡선은 Be-doped 시료가 가장 빨리 감소하였으며, Si-doped 시료가 가장 길게 나타났다. 이러한 결과로부터 $In_{0.64}Al_{0.36}Sb$의 광학적 특성은 성장 온도, dopant type, 도핑 농도에 따라 변화하는 것을 확인하였다.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.29-34
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• 2015

N,N'-Diferuloyl-putrescine (DFP) present in plants such as Sophora japonica has been reported to have skin depigmentative and antioxidative activities. In this study, DFP, usually presents in nature a very little amount and its derivative (DFP-D) were synthesized in a large quantity for the use as functional cosmetical materials. The antioxidative activities of synthesized DFP and DFP-D were evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, chemiluminescence assay, and cell protective effect induced by $^1O_2$, stress. DFP and DFP-D showed DPPH radical scavenging activities ($FSC_{50}$) at $61.25{\pm}2.25{\mu}M$ and $12.92{\pm}0.72{\mu}M$, respectively. ROS (reactive oxygen species) scavenging activities ($OSC_{50}$) in the $Fe^{3+}-EDTA/H_2O_2$ system of DFP and DFP-D were 2 times ($1.84{\pm}0.12{\mu}M$) and 13 times ($0.174{\pm}0.01{\mu}M$), respectively higher than that of L-ascorbic acid. $^1O_2$, one of ROS playing a key role in the skin photo-aging, induces cellular membrane damages. DFP-D ($50{\mu}M$) showed good cell protective effects (${\tau}_{50}=80.2min$) about 2 times more than that of (+)-${\alpha}$-tocopherol (${\tau}_{50}=43.6min$). These results suggest that the great antioxidative activities of DFP and DFP-D could be applied to cosmetic industries as functional cosmetic materials.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.11-21
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• 2004

Crystallization of CaC $O_3$ from the solutions of various degrees of supersaturation was carried out by a spontaneous precipitation method. The solution was kept at $25^{\circ}C$ and pH 6.9∼8.8. The solution compositions were varied in two ways: (1) The total carbonate, [C $O_3$]$_{Τ}$, to total calcium. [Ca]$_{Τ}$, ratios vary as ; [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$ >1. [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$=1, and [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$<1. (2) The total calcium concentration, [Ca]$_{Τ}$, held at 0.02 mo1/d $m^3$, 0.2 mo1/d $m^3$, and 0.4 mo1/d $m^3$. We found that the CaC $O_3$ phase crystallized from the solutions of [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$ $\geq$ 1 was mostly calcite with less than 1% of vaterite, while the CaC $O_3$ crystals precipitated from low carbonate concentration toward calcium concentration, [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$ < 1, were dominated by vaterite crystals. It appears that the polymorph of CaC $O_3$ precipitate was mainly controlled not by the calcium concentration but by the carbonate concentration during the spontaneous precipitation. Also, we found that the surface roughness of vaterite increased with decreasing carbonate concentration from 0.8 or 0.5 of [C $O_3$]$_{Τ}$/[Ca]$_{Τ}$ ratios and the surface area of vaterite increased from 5.64∼7.34 $\mu\textrm{m}$ to 8.39∼10.3 $\mu\textrm{m}$.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.99-99
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• 2003

Epidermal growth factor (EGF) induces well-documented mitegenic and differentiating effects on murine and bovine preimplantation embryos. However, the effects of EGF on apoptosis and implantation-related gene expression in bovine embryos developing in vitro have not been evaluated. The objective of this study was to determine the effects of exogenous EGF in the presence and absence of BSA on the preimplantation development of bovine embryos. In addition, we measured cell number, apoptosis, and expression of apoptosis and implantation-related genes of the blastocysts that developed in these culture conditions. In vitro produced bovine embryos were randomly cultured in the same medium containing 0 or 10 ng/$m\ell$ EGF in the presence and absence of 0.8% BSA. More 2-cell embryos developed into blastocysts at day 7 when BSA was present than when BSA was absent. The addition of 10 ng/$m\ell$ EGF into the medium did not significantly increase the developmental rate and the cell numbers per blastocyst. However, addition of EGF in the presence of 0.8% BSA significantly reduced the degree of apoptosis in the blastocysts (P< 0.01). To investigate whether EGF modulates mRNA expression of apoptosis-related genes, mRNA was prepared from single blastocysts and each preparation was subjected to RT-PCR for Bcl-2 and Bax transcripts. EGF did not alter the relative abundance of Bax gene expression in the presence of BSA, but increase Bcl-2 (P < 0.01). The relative abundance of Interferon tau expression was increased by EGF treatment in the presence of BSA. These results suggest that EGF and BSA synergistically enhance Bcl-2 and interferone tau gene expression, which may result in a net increase in viability in bovine embryos.

• Applied Biological Chemistry
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• v.24 no.4
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• pp.252-259
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• 1981

The effects of tunicamycin (TM) on the growth and ${\alpha}-amylase$ productivity of B. amyloliquefaciens K were studied. The minimal growth inhibitory concentration was $0.25{\mu}\textrm{g}/m\ell$ and its ${\alpha}-amylase$ was stable up to $50^{\circ}C$. When the saking culture with $1{\mu}\textrm{g}/m\ell$ of Tunicamycin caused the change of cell shape from form rod to irregular circular form and the mycelium lysis. the grow th of His-, $TM^{\tau}$ mutant obtained by treatment of TM and ultraviolet ray was similar to that of the parent strain, but the productivity of ${\alpha}-amylase$, protease, and RNase was lower than that of the parent.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.275-282
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• 2010

The effect of swirl flow on NOx in a nonpremixed turbulent hydrogen jet with coaxial air was studied. The swirl vane angle was varied from $30^{\circ}$ to $90^{\circ}$. The fuel jet air velocity and coaxial air velocity were varied in an attached flame region as $u_F=85{\sim}160m/s$ and $u_A=7{\sim}14m/s$. The objective of the current study was to analyze the characteristics of nitrous oxide emission in a swirl flow and to propose a new parameter for EINOx scaling. The experimental results show that EINOx decreases with the swirl vane angle and increased with flame length. Further, EINOx scaling factors can be determined by considering the effective diameter ($d_{F,eff}$) in a far field concept. The EINOx increased in proportion to the flame residence time (${\sim}{\tau_R}^{1/2.8}$) and the global strain rate (${\sim}{S_G}^{1/2.8}$).