• 제목/요약/키워드: N2B27

검색결과 555건 처리시간 0.031초

One-step Synthesis of Supramolecular Rectangles Starting from ($\eta^5$-Pentamethylcyclopentadienyl)rhodium(III) Aqua Complex

  • 한원석;이순원
    • 한국결정학회:학술대회논문집
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    • 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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    • pp.27-27
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    • 2002
  • [Cp*Rh(H₂O)₃](OTf)₂ (1) reacts with a stoichiometric amount of A and B [ A = Me₃SiN₃, B = 4,4'-bipridyl, (2a), A = Me₃SiNCO, B = 4,4'-bipridyl (2b)] in acetone at room temperature for 3 h to give the supramolecular complexes [Cp*₄Rh₄(μ-A)₄(μ-B)₂] [A = Me₃SiN₃, B = 4,4'-bipridyl, (2a), A = Me₃SiNCO, B = 4,4'-bipridyl (2b)]. Complexes 2a and 2b have been structurally characterized by X-ray diffraction.

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Relationship between Maximum Stem Volume and Density during a Course of Self-thinning in a Cryptomeria japonica Plantation

  • Ogawa, Kazuharu;Hagihara, Akio
    • The Korean Journal of Ecology
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    • 제27권1호
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    • pp.27-33
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    • 2004
  • Cryptomeria japonica plantation was monitored every year during 15 years from 1983 to 1997 for stem diameter and volume. The reciprocal equation, 1/Y = A + B/N, was applied to the relationship between cumulative volume Y and cumulative number N from the largest tree in the stand each year. The parameters A and B, which means respectively the reciprocal of an asymptotic value of total stand stem volume and the reciprocal of the maximum stem volume, are related by a power function. The power functional relationship between A and B derived a linear relationship of B-points ( $N_{B}$, $V_{B}$; $N_{B}$ = B/A, $Y_{B}$ = 1/2A) of each Y-N curve on log-log coordinates. The gradient of B-point line was so steep that the Y-N curve moved parallel upward year by year. The time trajectory of mean stem volume (W) and density ($\rho$) provided evidence in favor of the 3/2 power law of self-thinning, because the gradient of W - $\rho$ trajectory on log-log coordinates approximated to -3/2 at the final stage of stand development. On the basis of the results of Y-N curves and W - $\rho$ trajectory, the time trajectory of maximum stem volume $W_{max obs}$ and $\rho$ was derived theoretically. The gradient of $W_{max obs}$ - $\rho$ trajectory on log-log coordinates is calculated to be -0.6105 at the final stage. The gradient of $W_{max obs}$ - $\rho$ trajectory was steeper than that of W - $\rho$ trajectory at the early stage, while the former is gentler than the latter at the later stage.stage.e.age.e.

청국장 균주의 선발과 발효 특성 (Selection and Fermentation Characteristics of Cheongbukjang Strains)

  • 우승미;권중호;정용진
    • 한국식품저장유통학회지
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    • 제13권1호
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    • pp.77-82
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    • 2006
  • 본 연구에서는 혈전용해능이 우수한 균주를 선별하여 청국장의 발효 특성을 비교 조사하였다. 시판청국장에서 분리된 5종 균주의 혈전용해능을 비교한 결과, N2가 $41.7\%$(Plasmin lunit/mL과 비교)로 가장 높게 나타났고 N3, N5가 각각 $27.8\%$를 나타내었다. N2 균주의 kit동정 결과, B. subtilis와 $90.1\%$ 유사한 균주로 나타났다. 이를 활용하여 청국장을 제조한 결과, 분양균주에서는 B. subtilis (KCTC 3014)가 가장 많은 점질물을 생성하였고, 혈전용해능과 아미노태질소 함량도 가장 높은 것으로 나타났다. 그리고 분리균주에서는 B. subtilis N2가 점질물 함량, 혈전용해능, 아미노태질소 함량이 가장 높은 것으로 나타났다. 증자시간에 따른 영향을 조사한 결과 B. subtilis (KCTC 3014)와 B. subtilis N2를 접종한 청국장은 증자시간을 45분이 적합한 것으로 나타났으며, 발효시 간은 20시간정도가 적합한 것으로 나타났다.

Linear Operators which Preserve Pairs on which the Rank is Additive

  • Beasley, LeRoy B.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제2권2호
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    • pp.27-30
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    • 1998
  • Let A and B be $m{\times}n$ matrices. A linear operator T preserves the set of matrices on which the rank is additive if rank(A+B) = rank(A)+rank(B) implies that rank(T(A) + T(B)) = rankT(A) + rankT(B). We characterize the set of all linear operators which preserve the set of pairs of $n{\times}n$ matrices on which the rank is additive.

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Transdifferentiation of α-1,3-galactosyltransferase knockout pig bone marrow derived mesenchymal stem cells into pancreatic β-like cells by microenvironment modulation

  • Ullah, Imran;Lee, Ran;Oh, Keon Bong;Hwang, Seongsoo;Kim, Youngim;Hur, Tai-Young;Ock, Sun A
    • Asian-Australasian Journal of Animal Sciences
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    • 제33권11호
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    • pp.1837-1847
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    • 2020
  • Objective: To evaluate the pancreatic differentiation potential of α-1,3-galactosyltransferase knockout (GalTKO) pig-derived bone marrow-derived mesenchymal stem cells (BM-MSCs) using epigenetic modifiers with different pancreatic induction media. Methods: The BM-MSCs have been differentiated into pancreatic β-like cells by inducing the overexpression of key transcription regulatory factors or by exposure to specific soluble inducers/small molecules. In this study, we evaluated the pancreatic differentiation of GalTKO pig-derived BM-MSCs using epigenetic modifiers, 5-azacytidine (5-Aza) and valproic acid (VPA), and two types of pancreatic induction media - advanced Dulbecco's modified Eagle's medium (ADMEM)-based and N2B27-based media. GalTKO BM-MSCs were treated with pancreatic induction media and the expression of pancreas-islets-specific markers was evaluated by real-time quantitative polymerase chain reaction, Western blotting, and immunofluorescence. Morphological changes and changes in the 5'-C-phosphate-G-3' (CpG) island methylation patterns were also evaluated. Results: The expression of the pluripotent marker (POU class 5 homeobox 1 [OCT4]) was upregulated upon exposure to 5-Aza and/or VPA. GalTKO BM-MSCs showed increased expression of neurogenic differentiation 1 in the ADMEM-based (5-Aza) media, while the expression of NK6 homeobox 1 was elevated in cells induced with the N2B27-based (5-Aza) media. Moreover, the morphological transition and formation of islets-like cellular clusters were also prominent in the cells induced with the N2B27-based media with 5-Aza. The higher insulin expression revealed the augmented trans-differentiation ability of GalTKO BM-MSCs into pancreatic β-like cells in the N2B27-based media than in the ADMEM-based media. Conclusion: 5-Aza treated GalTKO BM-MSCs showed an enhanced demethylation pattern in the second CpG island of the OCT4 promoter region compared to that in the GalTKO BM-MSCs. The exposure of GalTKO pig-derived BM-MSCs to the N2B27-based microenvironment can significantly enhance their trans-differentiation ability into pancreatic β-like cells.

P/S 비율과 n-6/n-3 비율을 달리한 식이지방이 흰쥐의 Thromboxane B2 와 6-Keto prostaglandin F1$\alpha$ 합성에 미치는 영향 연구 (Effects of n-6/n-3 and P/S Ratio of Dietary Lipid on Thromboxane B2 and 6-Keto prostaglandin F1$\alpha$ Production in Rat)

  • 김우경
    • Journal of Nutrition and Health
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    • 제27권6호
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    • pp.574-582
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    • 1994
  • The effects of age and dietary fatty acid composition on prostagladin production was investigated in Sprague-Dawley strain male rats. Animals weighing 88.6$\pm$2.2g were fed 10% dietary fat(W/W, 20% of total energy). The P/S ratios of dietary lipid were three levels(0.5, 1, 2) and there were three different levels of n-6/n-3 fatty acid ratio(2, 4, 8) in each P/S ratio. The experimental period were 1 month and 12 months, respectively. The results of this study were as follows. As the age of rats increased, the plasma thromboxane B2 production increased, but aorta 6-keto prostaglandin F1$\alpha$ decreased. When a higher amount of n-3 fatty acid was fed in each P/S ratio, the relative percentage of linolenic acid and EPA in platelet increased.

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DFT Study of Bis(Crown-Ether) Analogue of Troger’s Base Complexed with Bisammonium Ions: Hydrogen Bonds

  • Kim, Kwan-Ho;Choe, Jong-In
    • Bulletin of the Korean Chemical Society
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    • 제27권11호
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    • pp.1737-1740
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    • 2006
  • The optimized structures and complexation energies of bis(18-crown-6-ether) analogue (2) of Trgers base (1) with a series of primary alkylbisammonium ions have been calculated by DFT B3LYP/6-31G(d,p) method. The calculated complexation efficiency (-142.84 kcal/mol) of 2 for butane-1,4-diylbisammonium guest is better than twice of the value (-61.40 kcal/mol) for butylammonium ion. The multiple hydrogen-bond abilities for the complexes are described as the function of the length of the alkyl substituents of the bisammonium guests with normal-alkyl chain [$-(CH_2)_{n-}$, n = 4-8]. The longer bisammonium guest shows the stronger hydrogen-bonding characterizations (the distance and the quasi-linear angle of the N-H…O) to the host 2 than the shorter bisammonium ions. These calculated results agree with the experimental data of the complexation of 2 with bisammonium salts ([$NH_3(CH_2)_nNH_3$] $Cl_2$).

열적 안정한 압력센서 제작을 위한 보론(B) 이온 주입 n형 Si 에피 전극 연구 (A Study of B-implanted n Type Si Epi Resistor for the Fabrication of Thermal Stable Pressure Sensor)

  • 최경근;강문식
    • 센서학회지
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    • 제27권1호
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    • pp.40-46
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    • 2018
  • In this paper, we focus on optimization of a boron ($^{11}B$)-implanted n type Si epi substrate for obtaining near-zero temperature coefficient of resistance (TCR) at temperature range from 25 to $125^{\circ}C$. The $^{11}B$-implantation on the N type-Si epi substrate formed isolation from the rest of the N-type Si by the depletion region of a PN junction. The TCR increased as the temperature of rapid thermal anneal (RTA) was increased at the temperature range from $900^{\circ}C$ to $1000^{\circ}C$ for the $p^+$ contact with implantation at dose of $1E16/cm^2$, but sheet resistance of this film was decreased. After the optimization of anneal process condition, the TCR of $1126.7{\pm}30.3$ (ppm/K) was obtained for the $p^-$ resistor-COB package chips contained $p^+$ contact with the implantation of $5E14/cm^2$. This shows the potential of the $^{11}B$-implanted n type Si epi substrate as a resistor for pressure sensor in thermal stable environment applications..

PbO2 전극을 이용한 산화제 생성과 염료 Rhodaime B 제거 (Formation of Oxidants and Removal of Dye Rhodamine B using PbO2 Electrode)

  • 박영식
    • 한국물환경학회지
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    • 제27권2호
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    • pp.194-199
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    • 2011
  • This study has been carried out to evaluate the performance of $PbO_2$ electrode for the purpose of degradation of N,N-Dimethyl-4-nitrosoaniline (RNO, indicator of OH radical), generation of ozone and decolorization of Rhodamine B (RhB) in water. The effect of the applied current (0.2~1.2 A), electrolyte type (NaCl, KCl and $Na_2SO_4$), electrolyte concentration (0.0~2.5 g/L) and solution pH (3~11) were evaluated. Experimental results showed that RhB and RNO removal were increased with the increase of current, NaCl dosage and decrease of pH. Ozone generation tendencies appeared with the almost similar to the RhB and RNO degradation, except of solution pH (Ozone generation was increased with increase of pH). Optimum current for RhB degradation and consumption of electric power was 1.0 A. The RhB degradation with Cl type electrolyte were higher than that with the sulfate type. Optimum NaCl dosage for RhB degradation was 1.0 g/L.

TOEPLITZ TYPE OPERATOR IN ℂn

  • Choi, Ki Seong
    • 충청수학회지
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    • 제27권4호
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    • pp.697-705
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    • 2014
  • For a complex measure ${\mu}$ on B and $f{\in}L^2_a(B)$, the Toeplitz operator $T_{\mu}$ on $L^2_a(B,dv)$ with symbol ${\mu}$ is formally defined by $T_{\mu}(f)(w)=\int_{B}f(w)\bar{K(z,w)}d{\mu}(w)$. We will investigate properties of the Toeplitz operator $T_{\mu}$ with symbol ${\mu}$. We define the Toeplitz type operator $T^r_{\psi}$ with symbol ${\psi}$, $$T^r_{\psi}f(z)=c_r\int_{B}\frac{(1-{\parallel}w{\parallel}^2)^r}{(1-{\langle}z,w{\rangle})^{n+r+1}}{\psi}(w)f(w)d{\nu}(w)$$. We will also investigate properties of the Toeplitz type operator with symbol ${\psi}$.