• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.669-673
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• 1993

The CO substitution reactions of the complex, $Cp(S-2,4-Me_2C_5H_5)CrCo$ with $PR_3(PR_3=PMePh_2,\;P(OCH_3)_3,\;PMe_2Ph)$ were investigated spectrophotometrically at various temperatures. From the reaction rates, it was suggested that the CO substitution reaction took place by first-order (dissociative) pathway. Activation parameters in decaline were ${\Delta}H^{\neq}\;=\;22.0\;kcal{\cdot}mol^{-1}$, ${\Delta}S^{\neq}=\;-3.8cal{\cdot}mol^{-1}{\cdot}K^{-1}$. Unusually low value of ${\Delta}S{\neq}$ suggests an ${\eta}^5-S{\to}{\eta}^5-U$ conversion of the pentadienyl ligand. This suggestion was confirmed by the Extended-Huckel molecular orbital (EHMO) calculations, which revealed that the total energy of $Cp(S-2,4-Me_2C_5H_5$)CrCO is about 0.42 kcal/mol more lower than that of $Cp(U-2,4-Me_2C_5H_5)CrCO$ and the energy of $[Cp(U-2,4-Me_2C_5H_5)Cr{\cdots}CO]^{\neq} $ transition state is about 2.43 kcal/mol lower than that of $[Cp(S-2,4-Me_2C_5H_5)Cr{\cdots}CO]^{\neq}$ transition state.

• Development and Reproduction
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• v.9 no.1
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• pp.49-52
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• 2005

The effects of cytochalasin B was studied for the cleavage and development of in vitro matured porcine follicular oocytes. The follicular oocytes were collected from slaughtered pig ovaries and matured for 65 hours. The matured oocytes were activated by 7% ethanol(v/v) in DPBS and the activated oocytes were subjected to cytochalasin B concentrations of 2.5, 5.0 and $7.5\;{\mu}g/mL$ for 3, 5 and 7 hours, and then the treated oocytes were cultured in NCSU23 with 0.4% BSA for 7 days. The cleavage rates were not different significantly in each treatment. However, the oocytes treated with $5.0\;{\mu}g/mL$ for 5 hours yielded a significantly higher morula rate(19.7%) than oocytes treated with $2.5\;{\mu}g/mL$ for 3 and 5 hours(9.4%). The sum rate of $2.5\;{\mu}g/mL$ concentration(10.5%) by hour was also significantly lower than those of 5.0(18.0%) and $7.5\;{\mu}g/mL$ concentration(14.6%). The blastocyst rate in oocytes treated with $5.0\;{\mu}g/mL$ for 3(9.4%) and 5 hours(9.0%) was significantly higher than the rate in oocytes treated with $2.5\;{\mu}g/mL$ for 3 hours(0%). The sum rate of $5.0\;{\mu}g/mL$ concentration also significantly higher than those of 2.5 and $7.5\;{\mu}g/mL$ concentration. The results demonstrated that the treatment of oocytes with cytochalasin B of $5.0\;{\mu}g/mL$ for $3{\sim}5$ hours was the optimal concentration and duration for parthenogenetic activation and blastocyst formation of in vitro matured porcine oocytes.

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.217-223
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• 1979

The present study was to investigate the effect of sugars on the psychrophillic spoilage in ground meat. The obtained results were summarized as follows: 1. The minimum pH values for the ground beef containing 2, 5 and 10 % glucose were 5.25, 5.15 and 4.5, respectively. For the ground pork, the respective values were 5.1, 4.45 and 4.1. 2. Total aerobes, coliform, lactic acid bacteria and lactobacillus counts per gram for the control and 2% glucose-contained ground beef after 9 days for storage at $5^{\circ}C$ were $8.3{\times}10^9vs\;6.0{\times}10^7,\;3.5{\times}10^5vs\;2.4{\times}10^3,\;5.8{\times}10^7vs\;4.7{\times}10^6$ and $3.6{\times}10^5vs\;4.2{\times}10^6$ respectively. For the ground pork, the respective values were $1.2{\times}10^{10}vs\;7.8{\times}10^8,\;3.4{\times}10^5vs\;3.1{\times}10^4,\;5.5{\times}10^7vs\;4.5{\times}10^6$ and $3.3{\times}10^5vs\;3.7{\times}10^5$. The glucose-added ground meat showed higher counts than those of the controls only in the case of lactobacillus without any apparent adverse effects. 3. The length of storage time until the depletion of added glucose was 12, 16 and 28 days for the 2, 5 and 10 % glucose contained ground beef and 9, 16 and 30 days for the ground pork, respectively. pH did not start to increase until the added glucose was depleted completely. 4. The addition of glucose extended significantly the average shelf-life of ground beef at refrigeration condition $(5^{\circ}C)$. The extended shelf-life over the control was 7, 9 and 12days for the 2, 5 and 10 % glucose contained ground beef and 8, 10 and 12 days for the respective ground porks. 5. Although the addition of disaccharides (maltose, lactose, saccharose) lowered the pH of ground meat, the extension of shelf-life as seen in glucose treatment was not affected. In fact, the higher the concentration of added disaccharides was, the greater the degree of putrefaction occurred.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.245-245
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• 1994

From the active fraction, cytotoxic constituents 1-5 were isolated and identified to be 2(S)-5,7-dihydroxy-8,2'-dimethoxyflavanone (1), wogonin (5,7-dihydroxy-8-methoxyflavone, 2), 5,7-dihydruxy-8,2'-dimethoxyflavone (3), 2(5) -5,7,2'-trihydroxy-8-methoxyflavanone (4), 2(S) - 5,2',5'-trihydroxy-7,8-dimethoxyflavanone (5), respectively, with those of specimens$\^$1-2)/

• Journal of the Korean Chemical Society
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• v.55 no.6
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• pp.974-977
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• 2011

Ethyl 1-aminotetrazole-5-carboxylate (1) has been utilized to construct a variety of novel tetrazolo [1,5-b]-1,2,5-oxadiazepine derivatives which repesent a relatively little explored group with interesting antibacterial activities. The synthesized compounds were elucidated using IR, $^1H$ NMR and mass spectroscopic methods, besides elemental analyses.

• Bulletin of the Korean Chemical Society
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• v.15 no.10
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• pp.849-852
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• 1994

The ${\alpha},{\beta}$-enoyl chiral iron complexes, ${\alpha},{\beta}-enoyl-{\eta}^5-(C_5H_5)Fe(CO)(PPh_3)$ (1) were prepared from ${\alpha},{\beta}-enoyl-{\eta}^5-(C_5H_5)Fe(CO)_2$(2) and triphenylphosphine through a photochemical ligand substitution followed by carbonylation.

• Reproductive and Developmental Biology
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• v.29 no.1
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• pp.19-24
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• 2005

The low density lipoprotein receptor-related protein 5 (LRP5) highly expressed in many tissues, including hepatocytes and pancreatic beta cells, can bind to apolipoprotein E. To evaluate in vivo roles of LRP5, we generated LRP5-deficient mice. LRP5 genomic DNA was isolated from TT2 embryonic stem (ES) cells. Targeting vector was constructed to disrupt an exon 18 of the mouse LRP5 gene and transfected into ES cells. Three homologous recombinants at LRP5 locus were identified from 178 G418-resistant clones. Chimeric males generated by morula aggregation technique were mated to C57BL/6 female mice. After achieving germ-line transmission, LRP5+/- females were crossed with LRP5+/- males to obtain LRP5-deficient mice. One line of mice lacking LRP5 gene was confirmed by Southern blotting. Such knock-out mice may serve as an effective animal model to study in vivo function of LRP5 gene.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.4
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• pp.194-199
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• 2012

The $LiMn_{1.5}Ni_{0.5}O_4$, substituting a part of Mn with Ni in the $LiMn_2O_4$, the spinel structure has good charge-discharge cycle stability and high discharge capacity at 4.7 V. In this study $LiMn_{1.5}Ni_{0.5}O_4$ powders were synthesized by polymerization complex method. The effect on the characteristics of synthesized $LiMn_{1.5}Ni_{0.5}O_4$ powders was studied with citric acid (CA) : metal ion (ME) molar ratio (5 : 1, 10 : 1, 15 : 1, 30 : 1) and calcination temperature ($500{\sim}900^{\circ}C$). Single phase of $LiMn_{1.5}Ni_{0.5}O_4$ was observed from XRD analysis on the powders calcined at low ($500^{\circ}C$) and high temperatures ($900^{\circ}C$). The crystalline size and crystallinity increased with calcination temperature. At low calcination temperature the particle size decreased and specific surface area increased as the CA molar ratio increased. On the other hand, high particle growth rate at high calcination temperature interfered the particle size reduction and specific surface area increase induced by the increase of CA molar ratio.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.99-104
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• 2012

The United States will proceed with the effort to modernize the GPS system, and one of its main content is to provide L5 signal. L5 will be transmitted in a radio band reserved exclusively for aviation safety services. And, L5, in combination with L1, will improve the position accuracy via ionospheric correction and robustness via signal redundancy. However, The acquisition processing time of L5 takes longer than that of L1 as the code length of L5 is 10 times longer than that of L1. To reduce this acquisition processing time, a higher number of correlators in the aquisition module should be used. However, there is a problem that this causes increase in the complexity of the correlator configuration and the computation power. So, in this paper, we propose L5 signal tracking scheme using tracking results in the GPS L1/L5 receiver. The proposed scheme could reduce the hardware complexity as the GPS L5 signal acquisition module is not needed, and provide fast and stable tracking of L5 signal by aiding L1 tracking results such as PRN, the code phase synchronization, and the Doppler frequency. The feasibility of the proposed scheme is demonstrated through simulation results.

• Korean Journal of Optics and Photonics
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• v.13 no.2
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• pp.105-112
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• 2002

We studied the optical and structural properties of conventional and ion-beam-assisted-deposition (IBAD) Nb$_2$O$_{5}$ films which were evaporated by an electron beam gun. The vacuum-to-air spectral shift and the cross sectional SEM images of the Nb$_2$O$_{5}$ films were investigated. The results show that the IBAD Nb$_2$O$_{5}$ films have a higher packing density than the conventional Nb$_2$O$_{5}$ films. The average refractive index of IBAD Nb$_2$O$_{5}$ films was increased, while the extinction coefficient was decreased compared with the conventional films. As the oxygen flow was increased, the average refractive index and extinction coefficient of the conventional and IBAD films decreased. Both the conventional and IBAD Nb$_2$O$_{5}$ films showed inhomogeneity in refractive index, and the degree of inhomogeneity of the IBAD Nb$_2$O$_{5}$ films became larger as the ion current density was increased. All Nb$_2$O$_{5}$ films were found to be amorphous by x-ray diffraction (XRD) analysis, and hence the crystal structure of Nb$_2$O$_{5}$ films was not changed by IBAD.