• Title/Summary/Keyword: cyclic group

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The Effects of 3-Isobutyl-1-methylxanthine (IBMX) on Nuclear and Cytoplasmic Maturation of Porcine Oocytes In Vitro

  • Kwak, Seong-Sung;Jang, Seung-Hoon;Jeong, Se-Heon;Jeon, Yubyeol;Biswas, Dibyendu;Hyun, Sang-Hwan
    • Journal of Embryo Transfer
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    • v.27 no.3
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    • pp.163-169
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    • 2012
  • The 3-isobutyl-1-methylxanthine (IBMX) is non-selective phosphodiesterase and is able to prevent resumption of meiosis by maintaining elevated cyclic AMP (cAMP) concentrations in the oocyte. The present study was conducted to analyze: (1) nuclear maturation (examined by the Hoechst staining), (2) whether cytoplasmic maturation (examined by the intracellular glutathione (GSH) concentration) of porcine oocytes is improved during meiotic arrest after prematuration (22 h) with IBMX. Before in vitro maturation (IVM), oocytes were treated with 1 mM IBMX for 22 h. After 22 h of pre-maturation, the higher rate of IBMX treated group oocytes were arrested at the germinal vesicle (GV) stage (42.3%) than control IVM oocytes (10.1%). It appears that the effect of IBMX on the resumption of meiosis has shown clearly. In the end of IVM, the reversibility of the IBMX effect on the nuclear maturation has been corroborated in this study by the high proportions of MII stage oocytes (72.5%) reached after 44 h of IVM following the 22 h of inhibition. However, intracellular GSH concentrations were lower in the oocytes treated with IBMX than the control oocytes (6.78 and 12.94 pmol/oocyte, respectively). These results demonstrate that cytoplasmic maturation in porcine oocytes pre-treated with IBMX for 22 h did not equal that of control oocytes in the current IVM system. These results indicate that pre-maturation with IBMX for 22 h may not be beneficial in porcine IVM system.

Improvement of the Functionalities by Phosphorylation of Hoki(Johnius belengeri) Frame Protein Hydrolysates (민태(Johnius belengeri) frame 단백질 가수분해물의 인산화에 의한 기능성 개선)

  • Jeon, You-Jin;Lee, Byoung-Jo;Park, Pyo-Jam;Byun, Hee-Guk;Kim, Se-Kwon
    • Applied Biological Chemistry
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    • v.42 no.2
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    • pp.128-133
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    • 1999
  • To enhance functional properties of 4 different hoki frame protein hydrolysates (30K, 10K, 5K and 1K hydrolysate) fractionated through a series of 30, 10, 5 and 1 kDa molecular weight cut-off membranes in order to decrease pore size, all hydrolysates were phosphorylated with sodium trimetaphosphate and altered phosphorylated 30K, 10K, 5K and 1K (P-30K, P-10K, P-5K and P-1K), respectively. The covalent attachment of anionic phosphate groups to polypeptide chains improved the functional properties, such as solubility, emulsifying properties and foaming properties, of hoki frame protein hydrolysates. Especially, P-30K hydrolysate with the highest molecular weight fraction possessed the most excellent functional properties among 4 different phosphorylated hydrolysates.

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Carbamate-Based Surface Reactions for Release of Amine Molecules from Electroactive Self-Assembled Monolayers

  • Hong, Dae-Wha;Kang, Kyung-Tae;Hong, Seok-Pyo;Shon, Hyun-Kyong;Lee, Tae-Geol;Choi, In-Sung S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.208-209
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    • 2011
  • In this work, we developed self-assembled monolayers (SAMs) of alkanethiols on gold that can release amine groups, when an electrical potential was applied to the gold. The strategy was based on the introduction of the electroactive carbamate group, which underwent the two-electron oxidation with simultaneous release of the amine molecules, to alkanethiols. The synthesis of the designed thiol compounds was achieved by coupling isocyanate-containing compound with hydroquinone. The electroactive thiols were mixed with hydroxyl-containing alkanethiol [$HS(CH_2)_{11}OH$] to form mixed monolayers, and cyclic votammetry was used for the characterization of the release. The mixed SAMs showed a first oxidation peak at +540 mV (versus Ag/AgCl reference electrode), demonstrating irreversible conversion from carbamate to hydroqinone with simultaneous release of the amine groups. The second and third cycles showed typical reversible redox reaction of hydroquinone and quione: the oxidation and reduction occurred at +290 mV and -110 mV, respectively. The measurement of ToF-SIMS further indicates that electrochemical-assisted chemical reaction successfully released amine groups. This new SAM-based electrochemistry would be applicable for direct release of biologically active molecules that contain amine groups.

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Isolation and Some Cultural Characteristics of ${\delta}-Aminolevulinic$ Acid - Producing Photosynthetic Bacteria (${\delta}-Aminolevulinic$ Acid 생산 광합성세균의 분리 및 배양특성)

  • Cheong, Dae-Yeol;Choi, Yang-Mun;Yang, Han-Chul;Cho, Hong-Yon
    • Applied Biological Chemistry
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    • v.40 no.6
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    • pp.561-566
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    • 1997
  • Screening, Identification and some cultural characteristics of ALA$({\delta}-aminolevulinic\;acid)$-producing photosynthetic bacteria were carried out for the optimal production of ALA, one of the bioherbicides. Among photosynthetic bacteria isolated from soil, marsh, pond, etc., KK-10 was the best producer of ALA and identified to be Rhodobacter capsulatus belonging to a typical group of nonsulfur purple bacteria. By addition of 15 mM LA (levulinic acid), an inhibitor of ALA dehydrase in cyclic tetrapyrrole biosynthesis, into culture broth at middle log phase of cell growths, ALA production was considerably increased to about 20-fold (28 mg/l). The combined supplementation of glycine and succinate, each with a concentration of 30 mM also enhanced production of ALA and activity of ALA synthase to about 50-fold (73 mg/l) and 2-fold, respectively. The isolated strain was able to produce upto 80 mg/l under the cultural condition optimized by addition 15 mM LA into the synthetic medium at four different points starting middle log phase.

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Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant

  • Yoon, Ki-Joon;Park, Young-Bum;Choi, Hyunmin;Cho, Youngsung;Lee, Jae-Hoon;Lee, Keun-Woo
    • The Journal of Advanced Prosthodontics
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    • v.8 no.6
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    • pp.465-471
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    • 2016
  • PURPOSE. The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. MATERIALS AND METHODS. Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of $1.0{\times}10^6$cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. RESULTS. Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. CONCLUSION. Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

The Learning Styles and Curriculum for Environmental Experience-Based Learning in Classroom of the Small Scale (소규모 학급의 환경 체험 학습을 위한 학습 유형화와 그 교육 과정)

  • Kwak, Hong-Tak;Lee, Ok-Hee
    • Hwankyungkyoyuk
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    • v.19 no.3
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    • pp.40-56
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    • 2006
  • The purpose of this study is to enhance elementary students' awareness of environment-friendly life and help them to prepare for a better life in the future. To achieve this purpose we examined the effect typical environmental experience-based learning activities, which were based on the local circumstances with high environmental-educational potential, have on the attitudes toward environment-friendly life. This study was carried out on the basis of typical environmental experience-based learning in the small class size. The research group used was composed of one sixth grade elementary school class called Sangroksu, whose total students were 9. The research period lasted from March 2005 to February 2006. To analyze the result of this study, two research methods were applied simultaneously : quantitative research methods and qualitative research methods. Especially statistical analysis in quantitative research methods by self-administrated questionnaire was done with SAS program. Qualitative research methods were analyzed in a cyclic pattern, including the processes of domain analysis, classification analysis, and factor analysis which continued to be associated with data-collecting methods. This research shows the following results. First of all, students have shown meaningful differences after typical environmental experience-based learning activities.(p<.05). Followings are fields of the differences - students‘ interest on the subject, their understanding levels of necessity for basic environmental facilities around us as well as for the kinds of environmental experience-based learning, awareness levels of various environmental problems, consciousness on environment conservation, and the practicing ability of environment - friendly lifestyles. Secondly, We have discovered improvements in the following fields after this study - the knowledge and understanding levels on our environment and human relationships, students' fundamental abilities to work out environmental problems, right ideas and appropriate attitudes on environment protection, the practicing ability of environment-friendly life styles, and their parents' understanding levels on the education related to environment. In conclusion, typical environmental experience-based learning activities have a positive effect on the improvement of elementary school students' environment-friendly life styles.

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A Zinc Porphyrin Sensitizer Modified with Donor and Acceptor Groups for Dye-Sensitized Solar Cells

  • Lee, Seewoo;Sarker, Ashis K.;Hong, Jong-Dal
    • Bulletin of the Korean Chemical Society
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    • v.35 no.10
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    • pp.3052-3058
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    • 2014
  • In this article, we have designed and synthesized a novel donor-${\pi}$-acceptor (D-${\pi}$-A) type porphyrin-based sensitizer (denoted UI-5), in which a carboxyl anchoring group and a 9,9-dimethyl fluorene were introduced at the meso-positions of porphyrin ring via phenylethynyl and ethynyl bridging units, respectively. Long alkoxy chains in ortho-positions of the phenyls were supposed to reduce the degree of dye aggregation, which tends to affect electron injection yield in a photovoltaic cell. The cyclic voltammetry was employed to determine the band gap of UI-5 to be 1.41 eV based on the HOMO and LUMO energy levels, which were estimated by the onset oxidation and reduction potentials. The incident monochromatic photon-to-current conversion efficiency of the UI-5 DSSC assembled with double-layer (20 nm-sized $TiO_2$/400 nm-sized $TiO_2$) film electrodes appeared lower upon overall ranges of the excitation wavelengths, but exhibited a higher value over the NIR ranges (${\lambda}$ = 650-700 nm) compared to the common reference sensitizer N719. The UI-5-sensitized cell yielded a relatively poor device performance with an overall conversion efficiency of 0.74% with a short circuit photocurrent density of $3.05mA/cm^2$, an open circuit voltage of 0.54 mV and a fill factor of 0.44 under the standard global air mass (AM 1.5) solar conditions. However, our report about the synthesis and the photovoltaic characteristics of a porphyrin-based sensitizer in a D-${\pi}$-A structure demonstrated a significant complex relationship between the sensitizer structure and the cell performance.

Relationship between body fat distribution and menstrual disorder in Obese Pre-menopausal Korean Women (한국 성인 비만여성의 체지방 분포와 월경 장애의 상관성 분석)

  • Choi, Ga-Ya;Song, Mi-Yeon;Shin, Hyun-Dai;Chung, Won-Suk
    • Journal of Korean Medicine for Obesity Research
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    • v.4 no.1
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    • pp.23-31
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    • 2004
  • Background: Obesity is associated with menstrual disorder. Especially, upper-body obesity affects on female reproductive function. Objectives: The goals were to investigate relation between fat distribution and menstrual disorder in obese pre-menopausal Korean females. The hypothesis were tested that there is a relation between upper body obesity and menstrual disorder. Design: A cross-sectional evaluation of 66 Females (baseline age $32.15{\pm}7,32)$ with body mass index $31.22{\pm}4.05\;kg/m^2$. Body composition was measured using bioimpedence analysis (BIA) and anthropometry was done by same observer. VAS and Multidimensional verval rating scale(MVRS) were checked for menstrual pain. Dual-Energy X-ray Absorptiometry (DXA) was measured for evaluating body fat distribution. Menstrual disorder and body fat distribution were compared using statistical methods. Results: TLFR and WH ratio was higher in menstrual cyclic disorder group than controls. There was negative relationship between VAS and TLFR. Conclusions: The data shows that disorder of menstrual cycle was associated with upper body obesity. WH ratio could be one of the factor of menstrual disorder. VAS was correlated with lower body obesity. Further studies for role of upper body fat distribution on female reproductive function and relationship between menstrual pain and fat distribution thought to be needed.

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Kinetic Study on Aminolysis of 4-Chloro-2-Nitrophenyl X-Substituted-Benzoates in Acetonitrile and in 80 mol % H2O/20 mol % DMSO: Effect of Medium on Reactivity and Reaction Mechanism

  • Kim, Ha-Ram;Um, Tae-Il;Kim, Min-Young;Um, Ik-Hwan
    • Bulletin of the Korean Chemical Society
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    • v.35 no.4
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    • pp.1128-1132
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    • 2014
  • A kinetic study on aminolysis of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-i) in MeCN is reported. The Hammett plot for the reactions of 6a-i with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ${\rho}_X$ = 1.03 and r = 0.78. The nonlinear Hammett plot is not due to a change in rate-determining step (RDS) but is caused by the resonance stabilization of substrates possessing an electron-donating group in the benzoyl moiety. The Br${\phi}$nsted-type plot for the reactions of 4-chloro-2-nitrophenyl benzoate (6e) with a series of cyclic secondary amines is linear with ${\beta}_{nuc}$ = 0.69, an upper limit for reactions reported to proceed through a concerted mechanism. The aminolysis of 6e in aqueous medium has previously been reported to proceed through a stepwise mechanism with a change in RDS on the basis of a curved Br${\phi}$nsted-type plot. It has been concluded that instability of the zwitterionic tetrahedral intermediate ($T^{\pm}$) in MeCN forces the reaction to proceed through a concerted mechanism. This is further supported by the kinetic result that the amines used in this study are less reactive in MeCN than in $H_2O$, although they are more basic in MeCN over 7 $pK_a$ units.

A Capillary Electrochromatographic Microchip Packed with Self-Assembly Colloidal Carboxylic Silica Beads

  • Jeon, In-Sun;Kim, Shin-Seon;Park, Jong-Man
    • Bulletin of the Korean Chemical Society
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    • v.33 no.4
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    • pp.1135-1140
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    • 2012
  • An electrochromatographic microchip with carboxyl-group-derivatized mono-disperse silica packing was prepared from the corresponding colloidal silica solution by utilizing capillary action and self-assembly behavior. The silica beads in water were primed by the capillary action toward the ends of cross-patterned microchannel on a cyclic olefinic copolymer (COC) substrate. Slow evaporation of water at the front of packing promoted the self-assembled packing of the beads. After thermally binding a cover plate on the chip substrate, reservoirs for sample solutions were fabricated at the ends of the microchannel. The packing at the entrances of the microchannel was silver coated to fix utilizing an electroless silver-plating technique to prevent the erosion of the packed structure caused by the sudden switching of a high voltage DC power source. The electrochromatographic behavior of the microchip was explored and compared to that of the microchip with bare silica packing in basic borate buffer. Electrophoretic migration of Rhodamine B was dominant in the microchip with the carboxyl-derivatized silica packing that resulted in a migration approximated twice as fast, while the reversible adsorption was dominant in the bare silica-packed microchip. Not only the faster migration rates of the negatively charged FITC-derivatives of amino acids but also the different migration due to the charge interaction at the packing surface were observed. The electrochromatographic characteristics were studied in detail and compared with those of the bare silica packed microchip in terms of the packing material, the separation potential, pH of the running buffer, and also the separation channel length.