• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.441-444
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• 2011

Type A and Type B and are commercial HTPB models, which are very popular prepolymer for polyurethane binder family. So the study has been performed on the physical, chemical characteristic of HTPB and viscosity, mechanical property of PBX-A applying to HTPB. But We excluded the Type A from Appication test, because of law Hydroxyl value. And in the case of Type B, Type B-1, 2 has mechanical disadvatage to apply to HTPB in the process comparing with B-3. It seems to make no problem if we change equivalence ratio or curing condition within standards. But if we are to apply process condition like R-45HT(US-sample), it would be essential to apply HTPB with higher Hydroxyl Value and hydroxyl Functionality.

• Archives of Pharmacal Research
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• v.27 no.9
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• pp.947-953
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• 2004

The antioxidative and hepatoprotective potentials of two anthraquinones, alaternin (2-hydroxy-emodin) and emodin, to scavenge and/or inhibit hydroxyl radicals generated by the Fenton reaction and to protect tacrine-induced cytotoxicity in human liver derived HepG2 cells were evaluated, respectively. The inhibitory activity on hydroxyl radical generated in a cell-free chemical system (FeSO$_4$/$H_2O$$_2$) was investigated by a fluorescence spectrophotometer using a highly fluorescent probe, 2$^1$,7$^1$-dichlorofluorescein. The hydroxyl radical scavenging activity was determined by electron spin resonance spectroscopy using 5,5-dimethy-1-pyrroline-N-oxide as hydroxyl radicals trapping agents. Tacrine-induced HepG2 cell toxicity was determined by a 3-［4,5-dimethylthiazole-2yl］-2,5-diphenyltertrazolium bromide assay. Although the scavenging activity of alaternin on hydroxyl radical was similar to that of emodin in dose-dependent pat-terns, the inhibitory activity exhibited by the former on hydroxyl radical generation was stron-ger than that of the latter, with $IC_{50}$/ values of 3.05$\pm$0.26 $\mu$M and 13.29$\pm$3.20 $\mu$M, respectively. In addition, the two anthraquinones, alaternin and emodin showed their hepatoprotective activ-ities on tacrine-induced cytotoxicity, and the EC$_{50}$ values were 4.02 11M and 2.37 $\mu$M, respec-tively. Silymarin, an antihepatotoxic agent used as a positive control exhibited the EC$_{50}$ value of 2.00 $\mu$M. These results demonstrated that both alaternin and emodin had the simultaneous antioxidant and hepatoprotective activities.ies.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.148-153
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• 1993

Composition and structure of synthetic glucitol fatty acid polyesters (GPE)-a potential fat substitute-were investigated. Also degree of substitution (D.S) of GPE was determined according to the relative ester distribution within it to evaluate the feasibility of GPE using as a fat substitute. The GPE was separated into single ester group by a normal-phase HPLC and D.S of it was identified to be 6. Absorption band at $1747\;cm^{-1}$ in the IR spectrum of GPE indicated that there were ester bonds within GPE molecules. which link fatty acid moiety to glucitol. Disappearance of the hydroxyl proton signals of glucitol in the H-NMR spectrum of GPE implied that most of hydroxyl groups in glucitol participated in the formation of ester bonds with fatty acids. In addition the D.S estimated from the quantitative proton integration of GPE coincided well with the D.S of GPE determined by hydroxyl value measurement. In conclusion, the GPE synthesized in this study was found to be a glucitol fatty acid hexaester so that it is expected to be used as a fat substitute in the near future.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.662-671
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• 2008

The behavior of hydrogen in the steel making process was investigated. The relation between the composition of ladle slag and hydrogen concentration in molten steel was considered. The hydrogen distribution ratio between ladle slag and molten steel was increased with increasing basicity of the slag; it was about 20 when the basicity of slag was 15. Hydroxyl capacity measured from the hydrogen distribution ratio between slag and the molten steel was comparatively corresponding to the value of hydroxyl capacity measured by the equilibrium reaction of slag and $H_2O$ gas. However, it is considerably different from the value calculated by regular solution model. The influence of hydrogen on a sticking type breakout is considered. The effect of hydrogen and $H_2O$ gas on the crystallization behavior of mold powder was investigated by DHTT (Dual hot thermocouple technique). As a result, it was proved that mold powder could be crystallized by $H_2O$ gas in the atmosphere. Therefore, it is concluded that $H_2O$ gas in the atmosphere can be a possible cause of the sticking type breakout that occasionally occurs in the continuous casting process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.21-27
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• 2023

Lotus Nelumbo nucifera seed protein (LSP) was isolated by alkaline solubilization after removing fat and phenolics by hexane and ethanol treatment. Antioxidant peptides from LSP were produced with Alcalase^® and pepsin and hydroxyl radical scavenging activities were determined. LSP-Alcalase^® hydrolysates showed higher hydroxyl radical scavenging activity than LSP-pepsin hydrolysates. To purify antioxidant peptides, LSP-Alcalase^® hydrolysates were subjected to high performance liquid chromatography (HPLC) separation on the C18 column and the active fraction was further purified using a Superdex^TM peptide 10/300 GL column. Finally, the active fraction (F8-2) was evaluated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging, and oxygen radical absorbance capacity (ORAC) assays. The EC₅₀ values of the F8-2 were 105.81±0.02 ㎍/mL for DPPH and 32.26±0.02 ㎍/mL for hydroxyl radical and the F8-2 exhibited 7.22 μM trolox equivalent (TE)/100 ㎍ F8-2. Glutathione (GSH), which is a positive control, showed EC₅₀ values of 19.87±0.01 ㎍/mL for DPPH and 15.95±0.03 ㎍/mL for hydroxyl radical and an ORAC value of 14.17±0.03 μM TE/100 ㎍ GSH. Finally, sixteen peptides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among them, Ile-Tyr and Leu-Tyr showed higher antioxidant scores.

• Journal of Environmental Science International
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• v.29 no.8
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• pp.793-800
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• 2020

The conventional development of multi-component electrodes is based on the researcher's experience and is based on trial and error. Therefore, there is a need for a scientific method to reduce the time and economic losses thereof and systematize the mixing of electrode components. In this study, we use design of mixture experiments (DOME)- in particular a simplex lattice design with Design Expert^Ⓡ program- to attempt to find an optimum mixing ratio for a three-component electrode for the high RNO degradation; RNO is an indictor of OH radical formation. The experiment included 12 experimental points with 2 center replicates for 3 different independent variables (with the molar ratio of Ru, Ti, Ir). As the Prob > F value of the 'Quadratic' model is 0.0026, the secondary model was found to be suitable. Applying the molar ratio of the electrode components to the corrected response model results is an RNO removal efficiency (%) = 59.89 × [Ru] + 9.78 × [Ti] + 67.03 × [Ir] + 66.38 × [Ru] × [Ir] + 132.86 × [Ti] × [Ir]. The R² value of the equation is 0.9374 after the error term is excluded. The optimized formulation of the ternary electrode for an high RNO degradation was acquired when the molar ratio of Ru 0.100, Ti 0.200, Ir 0.700 (desirability d value, 1).

• Journal of the Korean GEO-environmental Society
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• v.13 no.10
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• pp.69-76
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• 2012

This study focuses both on the quantitative measurement of hydroxyl radicals formed by an electron beam (E-beam) process and on the decomposition of pentachlorophenol(PCP) in the presence of $H_2O_2$ and $Fe^{3+}-EDTA$ as additives. To attain this objective, the quantitative measurement of hydroxyl radical was performed with the hydroylation of benzoic acid (BA), producing hydroxybenzoic acid (OHBA). As a result, the concentrations of hydroxyl radical measured were lower than those of hydroxyl radical predicted. Probably, it indicates that the reactive species generated during E-beam irradiation are able to scavenge the hydroxyl radicals. In particular, the degradation of PCP was promoted by the addition of $H_2O_2$ (< 1mM). On the other hand, its degradation as well as the generation of chloride ions as a by-product was inhibited by the addition of $H_2O_2$ (> 1mM), and thus carbon yield(%) of oxalic acid as a by-product was increased. During E-beam irradiation the addition of $Fe^{3+}-EDTA$ effectively decomposed the PCP, thus increasing the G-values. Considering the formation of OHBA and the decomposition of PCP, these results suggest that the addition of $Fe^{3+}-EDTA$ in the E-beam process can produce the further hydroxyl radicals and enhance the efficiency of PCP decomposition at low dose.

• The Korea Journal of Herbology
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• v.26 no.4
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• pp.95-99
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• 2011

Objective : In this study, we demonstrate the protective effect on oxidative DNA damage of leaf extracts from Abeliophylli distichi Folium via its antioxidant activity for the establishment of new value for the herbal medicine. Methods : Abeliophylli distichi Folium leaves were extracted with hot-water and ethylacetate (EtOAC). The 1,1-diphenyl-2- picrylhydrazyl (DPPH) radical and hydroxyl scavenging assay and $Fe^{2+}$ chelating assay were performed for antioxidative effect and ${\varphi}$X-174 RF I DNA cleavage assay and intracellular DNA damage assay were used for inhibitory effect of intracellular DNA damage. Results : In DPPH, Hydroxyl radical scavenging activity and $Fe^{2+}$ chelating activity of EtOAC extracts were 94.72%, 62.88%, 41.13%, and hot-water extracts were 88.86%, 56.7%, 37.4% at 200 ${\mu}g/m{\ell}$, respectively. Also, those extracts showed protective effect of DNA damage against the oxidative stress. Conclusion : These results indicated that the leaf extracts of Abeliophylli distichi Folium can be used as a natural antioxidants, which effectively inhibits the oxidative DNA damage.

• Applied Chemistry for Engineering
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• v.33 no.3
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• pp.322-327
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• 2022

Fucoidans were degraded by hydrogen peroxide under the electron beam (2.5 MeV) with various radiation doses (5 kGy, 10 kGy, 15 kGy, and 20 kGy) at room temperature. The degradation property was analyzed with a gel permeation chromatography (GPC-MALLS) method. An average molecular weight of fucoidan decreased from 99,956 at the irradiation dose of 0 kGy to 6,725 at the irradiation dose of 20 kGy. The solution viscosity of fucoidans showed a similar pattern to the molecular weight change. The number of chain breaks per molecule (N) increased with increasing the irradiation dose and concentration of hydrogen peroxide. The radiation yield of scission value markedly increased with increasing the irradiation dose up to 15 kGy. Also a 10% hydrogen peroxide concentration was more efficient than that of 5%. The structures of degraded fucoidan samples were studied with Fourier transform infrared spectroscopy (FT-IR). The results showed that the degradation process did not significantly change the chemical structure or the content of sulfate group. The sulfur content of each sample was determined with an Elemental Analyzer. With increasing the concentration of hydrogen peroxide, the ratios of sulfur/carbon, hydrogen/carbon, and nitrogen/carbon slightly decreased. The antioxidant activities of fucoidans were investigated based on hydroxyl radical scavenging activities. The ability of fucoidan to inhibit the hydroxyl radical scavenging activity was depended on its molecular weight.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.295-296
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• 2007

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