• 한국발생생물학회지:발생과생식
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• 제20권2호
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• pp.127-133
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• 2016

Purine metabolism is known factor for nuclear maturation of oocytes through both follicle cells and oocyte itself. However, it is largely unknown the roles of purine metabolism in the oocyte competence for fertilization and early development. In this study, the effects of adenosine in oocyte competence for development were examined using adenosine and its synthetic inhibitors. Adenosine treatment from GV intact stage for 18 hr (fGV) caused of decrease the fertilization rate but of increase the cleavage rate compared from the other stage treatment groups. Hadacidin did not effect on fertilization rate but increased cleavage rate without stage specificity. Adenosine did not block the effects of hadacidin with the exception of fGV group. Inhibition of purine synthetic pathways the fertilization rate was decreased in the fGV and fGVB groups but increased in the fMII group. Exogenous adenosine caused of decrease fertilization rate in the fGVB group but increase in the fMII group. Cleavage rate was dramatically increased in the adenosine treatment with synthetic inhibitors. It means that the metabolism of purine has stage specific effects on fertilization and cleavage. Exogenous adenosine had only can improve oocyte developmental competence when it treated at GV intact stage. On the other hand, endogenous synthesis in all maturation stage cause of increase the cleavage rate without effects on fertilization. These data suggest that adenosine at GV stage as a paracrine fashion and inhibitions of endogenous adenosine in all stage improve oocyte developmental competence.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.894-896
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• 2000

In vitro fertilization can be used for salvaging superior buffalo germplasm which otherwise goes waste after the slaughter of animals. This technology has also increased our basic understanding of growth of germ cells and embryos. The requirement of growing embryos is peculiar and stage specific. In the present study the cleavage and development of buffalo embryos were studied with homologous (buffalo) and heterologous (goat) oviductal cell co-culture systems. The cleavage rate improved significantly (p<0.01) in both homologous and heterologous co-culture as compared to control (55.3, 46.8 and 11.4%). The morula formation using homologous and heterologous oviductal cells also increased significantly as compared to control group (43.6, 21.9 & 1.9%). There was no blastula formation in control group, but addition of oviductal cells either from homologous or heterologous species significantly increased the blastula formation (9.5, 12.5%). The cleavage rate and embryo development was slightly better (non significant) in homologous as compared to heterologous oviductal cell culture. It was concluded that the use of oviductal cell co-culture (homologous and heterologous species) have significantly improved cleavage and development of buffalo embryos in vitro.

• 한국식품영양과학회지
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• 제29권4호
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• pp.568-574
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• 2000

Phytofluene를 dichloromethane에 용해하고 dry ice 상에서 ozonolysis를 행하였다. Ozonolysis에 의해 생성된 화합물은 silica gel chromatography를 행 하여 분획하고, photodiode array detector를 이용하여 ODS-HPLC로 분석하였다. Phytofluene을 5% Tween 40 수용액에 용해하고 37$^{\circ}C$, 24시간 자동산화시킨 결과, 다수의 carbonyl 및 acidic 화합물의 생성되었다. Phytofluene의 자동산화로부터 생성된 carbonyl 화 합물의 대부분은 ozonolysis에 얻어진 산화개열산물이 나타내는 HPLC상의 거동과 분광학적 특성이 서로 잘 일치하였다. 또한 phytofluene의 자동산화에 의해 생성된 중앙개열 acidic 화합물은 생성활성을 나타내는 4,5-didehydrogeranyl geranyl acid 표준품과 동일한 분광학 적 특성을 나타냈다. 이러한 결과는 in vitro 상의 산화적 조건하에서 phytofluene의 자동산 화에 의해 eccentric cleavage가 생성됨을 알 수 있었다.

• 열처리공학회지
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• 제26권6호
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• pp.306-316
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• 2013

Microstructure and fracture behavior of a multi-phase low-density steel were investigated. After hot-rolling and heat treatment, the microstructure of low-density steel was composed of coarse ferrite grains and elongated bands which include second phases such as austenite, martensite and ${\kappa}$-carbide depending on holding time during isothermal heat treatment. After tensile test, microcracks were observed at martensite or ${\kappa}$-carbide interface in the elongated bands. Coarse ferrite grains showed cleavage fracture behavior regardless of second phase. The cleavage fracture of ferrite could be attributed to their coarse grain size and solute atoms that increase ductile-to-brittle transition temperature of ferrite. Despite of the tendency of cleavage fracture in coarse ferrite grains, a specimen having coarse spheroidized ${\kappa}$-carbide particles in the elongated bands showed high total elongation of 30%. Thus, the easiness of plastic deformation in the elongated band seems to play an important role in retardation of cleavage crack formation in coarse ferrite grains.

• 한국식품과학회지
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• 제32권6호
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• pp.1227-1233
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• 2000

Lycopene을 dichloromethan에 용해하고 dry ice 상에서 ozonolysis을 행하였다. Ozonolysis에 의해 생성된 산화개열산물은 silica gel chromatography를 행하여 분획하고, photodiode array detector를 이용하여 ODS-HPLC와 LC-MS를 이용하여 분석하였다. Lycopene으로부터 생성된 carbonyl 화합물로 acycloretinal, apo-14'-lycopenal, apo-12'-lycopenal, apo-10'-lycopenal, apo-8'-lycopenal 그리고 apo-6'-lycopenal이 동정되었다. Lycopene을 toluene 및 Tween 40 수용액에 용해하고 $37^{\circ}C$에서 자동산화시킨 결과, 다수의 carbonyl 화합물이 생성되었다. Lycopene의 자동산화에 의해 생성된 carbonyl 화합물의 대부분은 ozonolysis에 얻어진 산화개열산물이 나타내는 HPLC상의 거동과 분광학적 특성이 서로 잘 일치하였다. 이러한 결과는 in vitro 상의 산화적 조건하에서 lycopene 자동산화에 의해 eccentric cleavage가 생성됨을 알 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1428-1432
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• 1999

[Fe$^{II}$(BLPA)DBCH]BPh₄ (1), a new functional model for the extradiol-cleaving catechol dioxygenases, has been synthesized, where BLPA is bis(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine and DBCH is 3,5-di-tert-butylcatecholate monoanion. ¹H NMR and EPR studies confirm that 1 has a high-spin Fe(II) (S = 2) center. The electronic spectrum of 1 exhibits one absorption band at 386 nm, showing the yellow color of the typical [Fe$^{II}$(BLPA)] complex. Upon exposure to O₂, 1 is converted to an intense blue species within a minute. This blue species exhibits two intense bands at 586 and 960 nm and EPR signals at g = 5.5 and 8.0 corresponding to the high-spin Fe(III) complex (S = 5/2, E/D = 0.11). This blue complex further reacts with O₂ to be converted to (μ-oxo)Fe$^{III}_2$ complex within a few hours. Interestingly, 1 affords intradiol cleavage (65%) and extradiol cleavage (20%) products after the oxygenation. It can be suggested that 1 undergoes two different oxygenation pathways. The one takes the substrate activation mechanism proposed for the intradiol cleavage products after the oxidation of the $Fe^II\;to\;Fe^{III}$. The other involves the direct attack of O₂ to $Fe^{II}$ center, forming the $Fe^{III}$-superoxo intermediate which can give rise to the extradiol cleavage products. 1 is the first functional Fe(II) complex for extradiol-cleaving dioxygenases giving extradiol cleavage products.

• Journal of Photoscience
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• 제12권2호
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• pp.83-85
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• 2005

Photochemical reactivities of ${\beta}-ethoxypropiophenones$ are changed dramatically by putting a halogen at a position to the carbonyl functionality. ${\alpha}-Bromo-{\beta}-ethoxypropiophenone$ gives C-Br bond cleavage products solely, but ${\alpha}-chloro-{\beta}-ethoxypropiophenone$ forms mainly the Yang photocyclization products upon irradiation. The different reactivities of two compounds can be explained by relative rates of C-X bond cleavage and a-hydrogen abstraction.

• Archives of Pharmacal Research
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• 제14권3호
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• pp.261-265
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• 1991

In a microbial cell-free extract system, side chain cleavage on various sterols and steroids was tested. The cell-free extracts of Mycobacterium sp. NRRL B-3805 showed the side chain cleavage activity on lithocholic acid to form 5$\beta$-androstan-3.17-dione. The properties of the activity were examined.

• Journal of Photoscience
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• 제7권1호
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• pp.35-37
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• 2000

Photolysis of $\alpha$-(o-alkylphenyl) indanones resulted in $\alpha$-cleavage followed by disproportionation to form E-and Z- ortho-formyl stilbenes. No evidences of hydrogen abstraction reactions were collected from these indanones. The minimum rate constant of $\alpha$-cleavage in the $\alpha$-(o-alkylphenyl) indanones was estimated to be 5.5$\times$10$^{10}$ s$^{-1}$ .

• Bulletin of the Korean Chemical Society
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• 제12권6호
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• pp.674-678
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• 1991

Methanolysis of a ${\beta}$-lactam ring of a cephalosporin was simulated with AM1 semiempirical quantum mechanical calculation. The tetrahedral intermediate TD1 from an O-protonated cephalosporin and a methanol transfers the proton intramolecularly to the C-4 carboxylate to generate an oxyanion, i.e., second tetrahedral intermediate TD2, which undergoes the amide bond cleavage without further protonation on the N-5. For this cleavage a low-energy barrier TS2 was located. According to the energy diagram, tetrahedral intermediates easily undergo ring cleavage even without the protonation on the amide nitrogen.