• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1633-1638
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• 2014

[6]-Gingerol is known as the major bioactive constituent of ginger. In the study, it was observed to effectively protect against ${\bullet}OH$-induced DNA damage ($IC_{50}$ $328.60{\pm}24.41{\mu}M$). Antioxidant assays indicated that [6]-gingerol could efficiently scavenge various free radicals, including ${\bullet}OH$ radical ($IC_{50}$ $70.39{\pm}1.23{\mu}M$), ${\bullet}O_2{^-}$ radical ($IC_{50}$ $228.40{\pm}9.20{\mu}M$), $DPPH{\bullet}$radical ($IC_{50}$ $27.35{\pm}1.44{\mu}M$), and $ABTS{^+}{\bullet}$radical ($IC_{50}$ $2.53{\pm}0.070{\mu}M$), and reduce $Cu^{2+}$ ion ($IC_{50}$ $11.97{\pm}0.68{\mu}M$). In order to investigate the possible mechanism, the reaction product of [6]-gingerol and $DPPH{\bullet}$ radical was further measured using HPLC combined mass spectrometry. The product showed a molecular ion peak at m/z 316 $[M+Na]^+$, and diagnostic fragment loss (m/z 28) for quinone. On this basis, it can be concluded that: (i) [6]-gingerol can effectively protect against ${\bullet}OH$-induced DNA damage; (ii) a possible mechanism for [6]-gingerol to protect against oxidative damage is ${\bullet}OH$ radical scavenging; (iii) [6]-gingerol scavenges ${\bullet}OH$ radical through hydrogen atom ($H{\bullet}$) transfer (HAT) and sequential electron (e) proton transfer (SEPT) mechanisms; and (iv) both mechanisms make [6]-gingerol be oxidized to semi-quinone or quinone forms.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.141-148
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• 1999

This study was to test whether the viability of bovine hatched blastocysts (HBs) can be maintained after vitrification and thawing. The HBs were produced in vitro at Day 9 and Day 10 after IVF, and they were classified to small (S-HBs; ø$\leq$300 ${\mu}{\textrm}{m}$) and large(L-HBs; ø＞300 ${\mu}{\textrm}{m}$) on the basis of embryo diameter using eyepiece micrometer. As freezing solution, we used EFS35 which consisted of 35% ethylene glycol (EG), 18% ficoll, 0.3 M sucrose and 10% FBS added in mDPBS. Vitrification was taken by two-step method, the HBs were equilibrated in 10% EG for 5 minutes and then shortly exposed in EFS35 and plunged into L$N_2$for 30~45 sec. After thawing, the survival rates were assessed by the re-expansion of the blastocoel during 2 h and 16 h of culture. The results obtained in these experiments were summarized as follows; 1) When the blastocysts(40.8%) recovered at Day 8 after IVF were further cultured for 24 h(Day 9 after IVF) and 48 h(Day 10 after IVF), the rates of HBs were 20.5% and 6.7%, respectively. Also, the total cell number of HBs on Day 9 was significantly higher than that of HBs on Day 10 (p＜0.01). 2) When the effects of freezing solution to the survival of Day 9 L-HBs were examined, the rate of vitrified group (75.7%) was significantly lower than 100% of control and exposed group(p＜0.05). 3) When the survival rates of vitrified HBs according to size and developmental age were examined, the data of L-HBs (75.5%) and S-HBs(63.6%) on Day 9 were slightly higher than those of L-HBs(64.3%) and S-HBs(60.7%) on Day 10. 4) Also, when the in vitro survival of Day 9 HBs was evaluated under different culture condition after thawing, the result in culture medium only (79.3%) was significantly higher than 43.2% in co-culture group (p＜0.05). These results demonstrated that bovine HBs can be successfully cryopreserved by two-step vitrification method using EFS35.

• Journal of Bio-Environment Control
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• v.4 no.1
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• pp.80-88
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• 1995

This survey has been conducted, mostly in inorganic ions, to get some basic data for the culture solution composition, analyzing water quality of some hydroponic farms. pH range was shown from 5.95 to 7.61 and the average of 6.75. Relatively wide range of EC, from 0.07 to 0.97 mS/cm and the average of 0.35 mS/cm were obtained. 19.5 percent of farms investigated showed over 0.5 mS/cm of EC, which means more careful culture solution composition and its management are needed in these farms. Na concentration ranged from 5.0 to 41.4 ppm and Cl concentration ranged from 10 to 99 ppm were shown and their average were 20.38 ppm and 35.16 ppm, respectively. Higher Na concentration compared to standard of 11.5 ppm was shown in 75% of farms and Higher Cl concentration compared to standard of 35.5 ppm was shown in 33.3% of farms. These concentration were considered rather high, which can cause salt accumulation in substrate mats. Ca and Mg concentrations were ranged from 1.60 to 131 ppm and 0.96 to 34.1 ppm, respectively. Average concentrations were 26.11 ppm in Ca and 8.10 ppm in Mg. In case of HCO$_3$, 24 to 295 ppm of concentration range and average of 63.13 ppm were obtained. Fe range was 0.01 to 0.87 ppm and its average was 0.14 ppm. This results showed that Fe elimination was necessary in well water.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.720-727
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• 2017

This study determined the optimum mix proportions for volcanic-ash-based geopolymer by analyzing the flow, setting time, and compressive strength. $Na2SiO_3$ and NaOH were used as alkali activators, and NaOH concentrations of 2, 4, 6, and 8M were used for different experimental cases. The A/B ratios examined were 0.25, 0.3, 0.35, 0.4, and 0.45, and the ratios of volcanic ash to blast furnace slag binder were 7:3, 6:4, and 5:5. In the experiment, the flow and setting time tended to decrease and the compressive strength increased as the molarity of NaOH in the geopolymer increased. The optimum molarity of NaOH was determined to be 4M. As the A/B ratio increased, the setting time decreased and the compressive strength increased. The most advantageous A/B ratio for the setting time and strength was 0.35. Increasing the ratio of volcanic ash resulted in a longer setting time and lower compressive strength. The optimum binder ratio was chosen as 6:4 based on the setting time and compressive strength. Thus, 4M of NaOH, an A/B ratio of 0.35, and binder ratio of 6:4 are considered as the proper parameters for the volcanic-ash-based geopolymer.

• Food Engineering Progress
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• v.21 no.2
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• pp.110-115
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• 2017

This study aimed to identify milling characteristics depending on the number of a cutting roller's air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be $38{\pm}0.5$ in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and $14.6^{\circ}C$ which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.

• Research in Plant Disease
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• v.29 no.1
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• pp.1-10
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• 2023

The establishment of a laboratory assay and a greenhouse assay was conducted for evaluating the pathogenicity of Macrophomina phaseolina causing soybean charcoal rot established. In the laboratory assay, microsclerotia and hyphae were used as inoculum. In the laboratory assays using microsclerotia as an inoculum, disease incidences of M. phaseolina NSW17-108 and HSM17-034 were higher at 35℃ than 25℃. Of the two isolates NSW17-108 and HSM17-034, the disease incidence of HSM17-034 isolated from diseased sesame is higher than that of NSW17-108 isolated from diseased soybean. When the mycelia of M. phaseolina were used as an inoculum, the disease incidence of NSW17-108 and HSM17-034 at 35℃ exceeded 80% even after only 5 days of inoculation. Even at 25℃, furthermore, that of HSM17-034 exceeded 80% 5 days later. In the pathogenicity assays at a greenhouse, toothpicks where microsclerotia were produced or microsclerotia harvested from potato dextrose agar medium were used as an inoculum. In all greenhouse assays, M. phaseolina NSW17-108 and HSM17-034 showed 40-60% of disease incidences 35-65 days after inoculation with the pathogen, depending on the inoculation method. Between the two isolates, the pathogenicity of HSM17-034 was stronger than that of NSW17-108, and this result was consistent with laboratory assay results. Since the laboratory and greenhouse test methods tested in this study have different advantages and disadvantages depending on each test method, it is thought that the test method that can meet the purpose of the study should be selected and used.

• Agricultural and Biosystems Engineering
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• v.3 no.1
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• pp.10-17
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• 2002

Quality attributes of apple are greatly affected by the cooling rate and environmental conditions during storage. Studies were conducted to evaluate the effect of cooling rate on different quality attributes of apple. The effect of $O_2$ pulldown rate of the CA chamber on the quality of apple was also determined. Two methods were used viz. conventional CA procedure and rapid CA procedure. Apples stored by medium and slow cooling methods lost its flesh firmness significantly from an initial level of 4.55 kg to 2.83 kg and 2.27 kg, respectively on 35 days after storage whereas, in rapid cooling, the firmness level changed from 4.55 kg to 3.20 kg on 35 days after storage. At the end of 35 days of storage, titratable acidity decreased insignificantly from an initial value of 0.24l% to 0.239% in the case of rapid CA whereas in the case of conventional CA it dropped significantly to 0.215% from its initial level. The initial flesh firmness of 4.55 kg also changed significantly to 4.05 kg on 35 days after storage in conventional CA whereas in rapid CA it changed to 4.36 kg, which was found to be non-significant at 5% level of significance. Total soluble solids increased from an initial level of $12.43^{\circ}$Bx to $12.60^{\circ}C.$ Bx on 35 days after storage in rapid CA whereas it increased to $13.07^{\circ}$ Bx in conventional CA. Ascorbic acid content of apple juice decreased insignificantly from 6.67 mg/100 mL to 5.87 mg/100 mL on 35 days after storage in rapid CA whereas in conventional CA, it decreased significantly to 5.27 mg/100 mL from its initial level.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.34-41
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• 2003

In this paper, 60GHz band transmitter and receiver for wireless LAN are designed and implemented using the broband amplifier and mixer fabricated by standard 0.1${\mu}{\textrm}{m}$ MIMIC process of MINT. Output power and gain of the RF transmitter are 0 ㏈m and 1.7㏈, respectively. Noise figure and gain of the receiver are 4.2㏈ and l5.7dB, respectively. Considering the sensitivity and LOS test, this system can communicate with BER of below than 10$^{-6}$ at a distance more than 35m. DSSS, which is strong for concealment and disturbance, is adopted.

• Journal of the Korean Chemical Society
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• v.35 no.2
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• pp.111-118
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• 1991

The kinetic of the gas phase reactions of ozone(0.5 torr) with sulfur dioxide was studied. The SO2 reaction was conducted in the 7∼22 torr range at 90∼155$^{\circ}$C. The reaction rate was faster than the reaction rate of O$_3$ in the presence of CO$_2$ alone. The reaction of O$_3$ with SO$_2$ follows the rate law: -d(O$_3)/dt=k_0(SO_2)(M)(O_3)+2k _1(SO_2)(O_3$). The first term of this rate law arises from a third order molecular reaction predominating in the lower temperature range and gave a rate constant k$_0$ = (9.35 $\pm$ 8.6) ${\times}$ 10$^9$e$^{-(11.05{\pm}2.04)kcal/RT}(M^{-2}s^{-1}$). The second term of the above rate law derived from a second order thermal decomposition reaction which was the major part of the reaction and gave a rate constant k$_0 =(9.35{\pm}8.6){\times}10^9e^{-(11.05{\pm}2.04)kcal/RT}(M^{-2}s^{-1}$). The overall reaction proceeds with kinetics of complex order composed mainly of second order and third order components.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.37-41
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• 1979

The kinetics of the reaction of benzyl m-nitrobenzenesulfonate with m-and p-substituted N,N-dimethylanilines in acetone have been investigated by an electric conductivity method. The effects of substituents on the reactivity of N,N-dimethylaniline and the existence of linear free energy relationship were discussed. The rate constants k were in the range 2.55∼487 $10^{-4}l{\cdot}mol^{-l}{\cdot}sec^{-1} (35^{\circ}C)$ and increased with the electron donating ability of substituents. In the present reaction, the Hammett plot was correlated with ${\sigma}$ substituent constant, especially using the new ${\sigma}$ value of 0.35 in p-MeO and it's ${\rho}$ value was found to be -1.37. r value for the reaction was very large than the value obtained in the reaction of benzyl bromide. $Br{\"{o}}nsted$ linear relationship was shown between rate constant and basicites except for p-MeO resulted from solvent effect. From the Bronsted plot, this reaction was suggested that the cleavage of the C${\cdot}{\cdot}{\cdot}$O bond in the $S_N2$ transition state proceed the bond formation.