• The Korean Journal of Physiology
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• v.20 no.2
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• pp.257-270
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• 1986

It has been reported that the luteal function may be regulated by the intracellular calcium in luteal cells (Higuchi et al, 1976; Dorflinger et at, 1984; Gore and Behrman, 1984) which is adjusted partially by $Ca^{++}-ATPase$ activities in luteal cell membranes (Verma and Pennistion, 1981). However, the physicochemical and kinetic properties of $Ca^{++}-ATPase$ in luteal membranes were not fully characterized. This study was, therefore, undertaken to partially characterize the physicochemical and kinetic properties of $Ca^{++}-ATPase$ system in luteal membranes and microsomal fractions, known as an one of the major $Ca^{++}$ storge sites (Moore and Pastan, 1978), from the highly luteinized ovary Highly luteinized ovaries were obtained from PMSG-hCG injected immautre female rats. Light membrane and heavy membrane fractions and microsomal fractions were prepared by the differential and discontinuous sucrose density gradient centrifugation method desribed by Bramley and Ryan (1980). Light membrane and heavy membrane fractions and microsomal fractions from highly luteinized ovaries are composed of the two different kinds of $Ca^{++}-ATPase$ system. One is the high affinity $Ca^{++}-ATPase$ which is activated in low $Ca^{++}$ concentration (Km, 10-30 nM), the other is low affinity $Ca^{++}-ATPase$ activated in higher $Ca^{++}$ concentration $(K_{1/2},\;40\;{\mu}M)$. At certain $Ca^{++}$ concentrations, activities of high and low affinity $Ca^{++}-ATPase$ are the highest in light membrane fractions and are the lowest in microsomal fractions. It appeares that high affinity $Ca^{++}-ATPase$ system have 2 binding sites for ATP (Hill's coefficient; around 2 in all membrane fractions measured) and the positive cooperativity of ATP bindings obviously existed in each membrane fractions. The optimum pH for high affinity $Ca^{++}-ATPase$ activation is around S in all membrane fractions measured. The lipid phase transition temperature measured by Arrhenius plots of high affinity $Ca^{++}-ATPase$ activity is around $25^{\circ}C$. The activation energies of high affinity $Ca^{++}-ATPase$ below the transition temperature are similar in each membrane fractions, but at the above transition temperature, it is the hightest in heavy membrane fractions and the lowest in microsomal fractions. According to the above results, it is suggested that intracellular $Ca^{++}$ level, which may regulate the luteal function, may be adjusted primarily by the high affinity $Ca^{++}-ATPase$ system activated in intracellular $Ca^{++}$ concentration range $(below\;0.1\;{\mu}M)$.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.49-57
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• 1983

The distribution and Properties of branched chain amino acid aminotransferase (EC 2.6. 1.42) was investigated in adult Fasciola hepatica. Fascicla hepatica was fractionated by differential centrifugation into nuclear, mitochondrial and cytosolic fractions. The activity of branched chain amino acid aminotransferase was measured by the method of Ichihara and Koyama (1966) . Isozyme patterns of this enzyule was also examined by DEAE-cellulose column chromatography. The results obtained were as follows; 1. The activity in homogenate was found to be 12.69 units/g wet tissue. The activity of this enzyme was relatively high compared with those in rat tissues. 2. The distribution of branched chain amino acid aminotransferase in the subcellular organelles showed that 87.8% of the activity was in cytosolic, 10.9% in mitochondrial and 1.3% was in nuclear fraction. 3. Cytosolic fraction of Fasciola hepatica contained Enzyme I, but not Enzyme II and III, of branched chain amino acid aminotransferase. Ensyme I was eluted by 50mM phosphate buffier from DEAE-cellulose column and catalyzed the transamination of all three branched chain amino acids. 4. The Enzyme I was purified about 22-folds increase in specific activity after chromatography on DEAE-cellulose. 5. The best substrate among three amino acids (leucine, isoleucine and valise) was L-isoleucine. 6. The optimal temperature of Enzyme I was $45^{\circ}C$ and the optimal pH was 8.2. 7. The Km value for leucine of Enzyme I was 4.17 mM. 8. The Km values for a-ketoglutarate and pyridoxal phosphate of Enzyme I were 0.41mM and $4.76{\times}10^{-3}{\;}mM$, respectively.

• Korean Journal of Materials Research
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• v.22 no.6
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• pp.275-279
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• 2012

(3-mercaptopropyl)trimethoxysilane (MPTMS) was used as a silylation agent, and modified silica nanoparticles were prepared by solution polymerization. 2.0 g of silica nanoparticles, 150 ml of toluene, and 20 ml of MPTMS were put into a 300 ml flask, and these mixtures were dispersed with ultrasonic vibration for 60 min. 0.2 g of hydroquinone as an inhibitor and 1 to 2 drops of 2,6-dimethylpyridine as a catalyst were added into the mixture. The mixture was then stirred with a magnetic stirrer for 8 hrs. at room temperature. After the reaction, the mixture was centrifuged for 1 hr. at 6000rpm. After precipitation, 150 ml of ethanol was added, and ultrasonic vibration was applied for 30 min. After the ultrasonic vibration, centrifugation was carried out again for 1 hr. at 6000rpm. Organo-modification of silica nanoparticles with a ${\gamma}$-methacryloxypropyl functional group was successfully achieved by solution polymerization in the ethanol solution. The characteristics of the ${\gamma}$-mercaptopropyl modified silica nanoparticles (MPSN) were examined using X-ray photoelectron spectroscopy (XPS, THERMO VG SCIENTIFIC, MultiLab 2000), a laser scattering system (LSS, TOPCON Co., GLS-1000), Fourier transform infrared spectroscopy (FTIR, JASCO INTERNATIONL CO., FT/IR-4200), scanning electron microscopy (SEM, HITACHI, S-2400), an elemental analysis (EA, Elementar, Vario macro/micro) and a thermogravimetric analysis (TGA, Perkin Elmer, TGA 7, Pyris 1). From the analysis results, the content of the methacryloxypropyl group was 0.98 mmol/g and the conversion rate of acrylamide monomer was 93%. SEM analysis results showed that the organo-modification of ultra-fine particles effectively prevented their agglomeration and improved their dispensability.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.107-112
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• 1990

The purpose of this study is to derive indirect values of volume of packed red cell(VPRC), without centrifugation, from erythrocyte sedimentation rate(ESR) of blood diluted with isotonic dextrose solution in cattle. Each of ten blood samples taken from apprently healthy Korean cows and Holstein cows was used to produce eight different mixture of autologous plasma and blood corpuscles such that their values of VPRC lay between 15 to 50ml/100ml, and then each of the blood mixture was again diluted with 5% dextrose solution. The measurements of ESR using 45 degree-angled capillary hematocrit tube, 1.1~1.2mm bore, ($45^{\circ}$-micro-ESR) were practised for the diluted blood of various levels of VPRC under the ambient temperature of $10^{\circ}$, $20^{\circ}$ and $30^{\circ}C$. Reliable values of VPRC on the basis of the correlating linear regressive equation to the ESR could be derived from the values of $45^{\circ}$-micro-ESR/hr in the mixture of one part of whole blood and one part of 5% dextrose solution(1:1). For an aid of practical use, authors suggested a list of the $45^{\circ}$-micro-ESR/hr values of the diluted blood equivalent to VPRC of whole blood.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.565-571
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• 2013

An enzyme ${\beta}$-galactosidase or ${\beta}$-galactohydrolase [EC3.2.1.23], commonly called lactase, mediates galacto-oligosaccharide (GOS) synthesis under conditions of high substrate concentrations. Also, lactase hydrolyzes ${\beta}$($1{\rightarrow}4$) lactose into glucose and galactose, the latter is successively transferred to free lactose to make various oligosaccharides via transgalactosylation. GOS is non-digestible to human digestive enzymes and has been used as a functional prebiotics. Among the 24 lactic acid bacteria (LAB) strains used, Lactobacillus paracasei YSM0308 was selected based on its exhibition of the highest ${\beta}$-galactoside hydrolysis activity, and the crude lactase was prepared for examination of reaction conditions to affect the GOS synthesis. Lactase activity was measured with a spectrophotometer using ONPG (o-nitropheyl ${\beta}$-D-galactopyranoside) method. Lactase activity was not detected in the culture supernatant and was mostly present in the cell pellet after centrifugation. Activity of the crude lactase preparation ranges from102 to 1,053 units/mL, with the highest activity determined for L. paracasei YSM0308. Optimal conditions for GOS synthesis are as follows: concentration of whey powder, pH, temperature, and time were 30%, pH 6.5-7.0, $30^{\circ}C$, and 4 h, respectively. The final GOS concentration was 19.41% (w/v) by the crude YSM0308 lactase, which was obtained from strain YSM0308 grown in the 10% (w/v) reconstituted whey-based medium.

• Korean Journal of Materials Research
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• v.21 no.2
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• pp.115-119
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• 2011

Si Nanowire (NW) field effect transistors (FETs) were fabricated on hard Si and flexible polyimide (PI) substrates, and their electrical characteristics were compared. Si NWs used as channels were synthesized by electroless etching method at low temperature, and these NWs were refined using a centrifugation method to get the NWs to have an optimal diameter and length for FETs. The gate insulator was poly(4-vinylphenol) (PVP), prepared using a spin-coating method on the PI substrate. Gold was used as electrodes whose gap was 8 ${\mu}m$. These gold electrodes were deposited using a thermal evaporator. Current-voltage (I-V) characteristics of the device were measured using a semiconductor analyzer, HP-4145B. The electrical properties of the device were characterized through hole mobility, $I_{on}/I_{off}$ ratio and threshold voltage. The results showed that the electrical properties of the TFTs on PVP were similar to those of TFTs on $SiO_2$. The bending durability of SiNWs TFTs on PI substrate was also studied with increasing bending times. The results showed that the electrical properties were maintained until the sample was folded about 500 times. But, after more than 1000 bending tests, drain current showed a rapid decrease due to the defects caused by the roughness of the surface of the Si NWs and mismatches of the Si NWs with electrodes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.104-113
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• 2012

Crab-like flavorants (CFs) were made from snow crab cooker effluent (SCCE) using response surface methodology (RSM) and reaction flavoring technology (RFT). Type A CF was made from SCCE via RSM, RFT, adding starch syrup, centrifugation, and microfiltration. Type B was made from type A by adding the food additives dimethyl sulfide, ethyl valerate and fish sauce. The stability of the CFs was evaluated in terms of the color values, sensory evaluation, and flavor profiles after storage for 90 days at three different temperatures: 10, 20, and $30^{\circ}C$. The compounds, ethanol and 3-methyl-1-butanol, were considered key components of off-flavor and a decrease in dimethyl-2-vinylpyrazine affected the occurrence of off-flavor. It may be a microbial metabolite arising from contamination and lab-scale micro-filtration. At the lowest temperature ($10^{\circ}C$), the decrease in volatile compounds, such as pyrazines, was not as dramatic as at $20^{\circ}C$ and $30^{\circ}C$ and alcohol formation was prevented or delayed. Therefore, it is necessary to store CFs at < $10^{\circ}C$ with suitable sterilization to preserve volatile flavor compounds and prevent off-flavor from occurring.

• The Korean Journal of Mycology
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• v.15 no.4
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• pp.217-223
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• 1987

Mitochondria in the L. edodes was purified by linear sucrose density gradient centrifugation. The mitochondrial ATPase activity was investigated by various wavelength illumination for 30 min at dark state. The mitochondrial ATPase activity was stimulated 1.6 fold by 680 nm illumination compared with dark control group. The mitochondrial ATPase activity of different light illumination time at 680 nm was stimulated 2.3 fold at 5 minutes compared with dark control group. Its optimum pH and temperature were found to be 7.5 and $59^{\circ}C$ after illumination for 5 minutes at 680 nm. The mitochondrial ATPase activity was activated by 5 mmol $Fe^{3+}$, 0.1 mmol $Fe^{2+}$, 0.1 mmol $Mg^{2+}$, 0.5 mmol $K^{+}$, and 0.1 mmol $Ca^{2+}$ ion. But, the enzyme was inhibited by 5 mmol $Na^{+}$ ion.

• The Korean Journal of Mycology
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• v.15 no.4
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• pp.224-230
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• 1987

Effects Of organic compound, photosensitizer and $K^+$ ion influx. On the light-induced ATPase of mitochondria in L. edodes purified by linear sucrose density gradient centrifugation were studied. The mitochondrial ATPase activity was investigated by various wavelength illumination at dark state. The mitochondrial ATPase was activated 139% and 128% by 10m mol dithiothreitol and 0.1m mol quinacrine, respectively. This enzyme also was activated 36% by 0.1m mol phenazine methosulfate as photosensitizer. But, 100 mg oligomycin and 1m mol phlorizin inhibited activity of enzyme to 48% and 45%, respectively. Its optimum wavelength was 690 nm on the effect of $K^+$ ion influx, its optimum pH and temperature were found to be 7.2 and $55^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.42-49
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• 2000

A new method for the quantitative determination of capsaicinoids in microcapsule has been developed. Among seventeen solvents tested for solubilizing wall material (gum arabic and modified starch) of microcapsule, dimethyl sulfoxide (DMSO) was selected as an optimal solvent. The most appropriate mixing ratio of microcapsule to DMSO for solubilizing wall material was 1 to 10(w/v). Appropriate carriersolubilizing temperature and time were $55^{\circ}C$ and 30 min, respectively. Also conditions for extracting oleoresin from the solubilized microcapsule were studied. The mixing ratio of ethanol to DMSO was optimal at 8 to 1(v/v). Optimized vortexing time was 5 min at 40㎐. Pecipitant was obtained by centrifugation at 21000 rpm for 15 min. The precipitant was reextracted with ethanol. The extracted supernatants were combined and adjusted to final volume of 25 ml. Extracted solutions were analyzed for quantitation of total capsaicinoids by employing HPLC and for quantitation of total carotenoids by spectrophotometric method. This method can be used to monitor changes of capsacinoid during manufacturing or storage of red pepper oleoresin microcapsule powder.