• Food Science of Animal Resources
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• v.27 no.1
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• pp.80-86
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• 2007

This experiment was conducted to investigate the changes of pork meat quality characteristics exposed to ozone gas for 5, 10, and 15 min and then vacuum packaged during storage for 0, 5, 10, 15, and 20 day at $4^{\circ}C$. The ozone gas exposed groups of pork loin cuts (OZM) had slightly higher pH value compared to the control at day 0 and 5 (p<0.01). The 15 min exposure of ozone gas groups showed significantly (p<0.01) higher TBARS value than that of control at the day 15 and 20. However, there was no significant difference in all groups at day 0,5, and 10. The CIE $L^*$ and $b^*$ values of OZM showed no significant difference between control and ozone gas treated groups during storage. The loin cut color of ozone gas exposure for 15 min had significantly lower CIE $a^*$ values than the other groups at day 0,5, and 15 (p<0.01). The aerobic plate count and coliform bacteria count of pork loin cuts exposed ozone gas significantly (p<0.01) was reduced at day 0 by about $0.45-1.04\;log_{10}CFU/g$ and $0.26-0.30\;log_{10}CFU/g$, respectively. As ozone gas exposure time extended, the aerobic plate count and coliform bacteria count of OZM were increased at day 0, 5, and 10 (p<0.01). However, there were no significant differences observed among groups at day 20 in the counts of aerobic and coliform bacteria. In conclusion, the meat cuts exposed to ozone gas for 5 and 10 min before packing may be a reasonable packing method regarding the effects of ozone level on meat oxidation, color change and microbial reduction.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.261-272
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• 1992

Tetradentate Schiff base Cobalt(II)(3MeOSED)$(H_2O)_2$ complexe was synthesized and allowed to react with dry oxygen to form oxygen adducts of Cobalt(III) complexes such as ${\mu}$-peroxo type [Co(III)(3MeOSED)(DMF)]$_2O_2$ and [Co(III)(3MeOSED)(DMSO)]$_2O_2$in DMF and DMSO or superoxo type [Co(III)(3MeOSED)(Py)]$O_2$ in pyridine. The oxygen adducted complex was investigated by cyclic voltammetry and DPP method with glassy carbon electrode in 0.1M TEAP-DMF (-DMSO,-Py) as supporting electrolyte solution. As a result the reduction reaction process occurred to four steps including prewave Of $O_2^-$in 1 : 1 oxygen adducted superoxo type [Co(III)(3MeOSED)(Py)]$O_2$complex and three steps not including prewave of $O_2^-$ in 1 : 2 oxygen adducted ${\mu}$-peroxo type [Co(III)-(3MeOSED)(DMF)]$_2O_2$ and [Co(III)(3MeOSED)(DMSO)]$_2O_2$. A superoxo type [Co(III)(3MeOSED)(L)]$O_2\;(L: CH_3OH)$ was generated with oxygen in methanol. Selectively oxidized hydrazobenzene $(H_2AB)$ to trans-azobenzene(t-AB) and the rate constant k for oxidation reaction of the following equation is $(2.96 {\pm} 0.2)$${\times}$ $10^{-1}$M/sec. $H_2AB$ + Co (II)(3MeOSED)$(L_2)+O_2\;{\rightleftarrow^K}$ [Co(III)(3MeOSED)(L)]$O_2{\cdot}H_2AB{\longrightarrow^K}$ Co(II(3MeOSED)$(L)_2$+t-AB+$H_2O_2 $.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.166-172
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• 2015

This study was performed to develop treatment method for reducing microbial contamination on Daruma (a semi-processed product of seasoned and dried squid) by combination of strong acidic hypochlorous water (SAHW) and ultrasonic waves (UW). The available chlorine concentration, oxidation reduction potential (ORP) and pH of SAHW were $69.67{\pm}0.58ppm$, $1071.33{\pm}4.16mV$ and 2.79, respectively. The 1.49 log CFU/g of viable cell count and 1.32 log CFU/g of Staphylococcus aureus was reduced, and Escherichia coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of sodium hypochlorite solution (SHS) for 120 min. The 3.62 log CFU/g of viable cell count and 3.22 log CFU/g of Staphylococcus aureus was reduced, and Escherichia coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 120 min. The antibacterial effects of SAHW were stronger than those of SHS at same available chroline concentration. SAHW treatment after washing strongly alkalic electrolyzed water (SAEW) showed better bactericidal effects than SAHW treatment only. The 4.0 log CFU/g of viable cell count was reduced, S. aureus was reduced below regulation limit (Log 2.0 CFU/g), and E. coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 90 min after washing with 20 times (w/v) of SAEW for 60 min. The viable cell number was reduced below detection limit and S. aureus was reduced below regulation limit when the Daruma was treated with 20 times (w/v) of SAHW for 60 min in ultrasonic washer. E. coli was reduced below detection limit when the Daruma was treated with 20 times (w/v) of SAHW for 10 min in ultrasonic washer. These results suggest that combination of SAHW and UW may be a good technique to reduce the microbial contamination in daruma.

• Journal of Chest Surgery
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• v.12 no.4
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• pp.383-394
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• 1979

Treatment of valvular heart disease with valve replacement has been one of the most popular procedures in cardiac surgery recently. Although, first effort was directed toward the prosthetic valve, it soon became popular that bioprosthesis, the valvular xenograft, was prefered in the majority cases. Valvular xenograft has some superiority to the artificial prosthetic valve in some points of thromboembolism and hemolytic anemia, and it also has some inferiority of durability, immunologic reaction and resistance to Infection. Tremendous efforts were made to cover the inferiority with several methods of collection, preservation, and valve mounting of the porcine valve or pericardium of the calf, and also with surgical technique of the valvular xenograft replacement. Auther has collected 320 porcine aortic valves immediately after slaughter, and aortic cusps were coapted with cotton balls in the Valsalva sinuses to protect valve deformity after immersion in the Hanks' solution, and oxidation, cross-linking and reduction procedures were completed after the proposal of Carpentier in 1972. Well preserved aortic valves were suture mounted in the hand-made tissue valve frame of 19, 21, and 23 mm J.d., and also in the prosthetic vascular segment of 19 mm Ld. with 4-0 nylon sutures after careful trimming of the aortic valves. Completed valves were evaluated with bacteriologic culture, pressure tolerance test with tolerane gauge, valve durability test in the saline glycerine mixed solution with tolerance test machine in the speed of 300 rpm, and again with pathologic changes to obtain following results: 1. Bacteriologic culture of the valve tissue in five different preservation method for two weeks revealed excellent and satisfactory result in view of sterilization including 0.65% glutaraldehyde preservation group for one week bacteriologic culture except one tissue with Citobacter freundii in 75% ethanol preserved group. 2. Pressure tolerance test was done with an apparatus composed of V-connected manometer and pressure applicator. Tolerable limit of pressure was recorded when central leaking jet of saline was observed. Average pressure tolerated in each group was 168 mmHg in glutaraldehyde, 128 mmHg in formaldehyde, 92 mmHg in Dakin's solution, 48 mmHg in ethylene oxide gas, and 26 mmHg in ethanol preserved group in relation to the control group of Ringer's 90 mmHg respectively. 3. Prolonged durability test was performed in the group of frame mounted xenograft tissue valve with 300 up-and-down motion tolerance test machine/min. There were no specific valve deformity or wearing in both 19, 21, and 23 mm valves at the end of 3 months (actually 15 months), and another 3 months durability test revealed minimal valve leakage during pressure tolerance test due to contraction deformity of the non-coronary cusp at the end of 6 months (actually 30 months) in the largest 23 mm group. 4. Histopathologic observation was focussed in three view points, endothelial cell lining, collagen and elastic fiber destructions in each preservation methods and long durable valvular tolerance test group. Endothel ial cell lining and collagen fiber were well preserved in the glutaraldehyde and formaldehyde treated group with minimal destruction of elastic fiber. In long durable tolerance test group revealed complete destruction of the endothelial cell lining with minimal destruction of the collagen and elastic fiber in 3 month and 6 month group in relation to the time and severity. In conclusion, porcine xenograft treated after the proposal of Carpentier in 1972 and preserved in the glutaraldehyde solution was the best method of collection, preservation and valve mounting. Pressure tolerance and valve motion tolerance test, also, revealed most satisfactory results in the glutaraldehyde preserved group.

• Analytical Science and Technology
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• v.22 no.4
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• pp.285-292
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• 2009

It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

• Korean Journal of Food Science and Technology
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• v.36 no.6
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• pp.937-942
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• 2004

Physicochemical properties and mineral composition of seaweed salts prepared by incineration and osmotic dehydration methods were determined. As the incineration temperature increased, yield of seaweed salts, insoluble solids, pH, alkalinity, and oxidation-reduction potential (ORP) decreased. Alkalinity of salt prepared with sea tangle was higher than that of sea mustard. ORP decreased by incineration above $700^{\circ}C$, and was lower in salt with sea tangle. As incineration temperature increased, amounts of K and Ca in seaweed salt increased, whereas that of Mg decreased. Potassium and Ca contents of seaweed salt increased remarkably compared with those of common salt. Potassium content of sea tangle salt was higher than that of sea mustard. As incineration time increased, yield of seaweed salts, insoluble solid content, and pH decreased, whereas ORP of the salt increased. Potassium content of seaweed salt with incineration time, while Ca and Na contents decreased after incineration of 8 and 4 hr, respectively. Yield of seaweed salt by osmotic dehydration increased as immersion time in sea water increased. pH of salt from sea mustard was higher than that of sea tangle. ORP of seaweed salt dried three times was -128.8 mV, significantly lower than that of salt prepared by incineration method. As sea water immersion time increased, Mg content of seaweed salt increased significantly, while Ca content decreased. Potassium content of seaweed salt was higher in sea tangle salt. In case of salt prepared by incineration of residuals, pH increased with immersion time but ORP decreased.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.329-336
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• 2006

Iron manufacturing process involves production of various by-product including slag, sludge, sintering and EAF(Electric Arc furnace dust). Some of the by-products such as EAF and sintering dust are disposed of as waste due to their high heavy metal contents. It has been notice for many years that the EAF dust also contain about 65% of Fe(0) and Fe(II) and then the possible utilization of the iron. One possibility is to apply the EAF as a lining material in conjunction with clay or HDPE liners, in waste landfill. The probable reaction between the leachate containing toxic elements such as TCE, PCE dioxine and $Cr^{6+}$ is reduction of the toxic materials in corresponding to the oxidation of the reduced iron and therefore diminishing the toxicity of the leachate. It is, however, prerequisite to evaluate the leaching characteristics of the EAF dust before application. Amelioration of the leachate would be archived only when the level of toxic elements in the treated leachate is less than that of in the untreated leachate. Several leaching techniques were selected to cover different conditions and variable environments including time, pH and contact method. The testing methods include availability test, pH-stat test and continuous column test. Cr and Zn are potentially leachable elements among the trace metals. The pH of the EAF dust is highly alkaline, recording around 12 and Zn is unlikely to be leached under the condition. On the contrary Cr is more leachable under alkaline environment. However, the released Cr should be reduced to $Cr^{3+}$ and then removed as $Cr(OH)_3$. Removal of the Cr is observed in the column test and further study on the specific reaction of Cr and EAF dust is underway.

• Clean Technology
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• v.24 no.1
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• pp.77-84
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• 2018

In this study, $Li_4Ti_5O_{12}$ anode materials for lithium ion battery were synthesized by dry ball-mill method. Polyvinyl chloride (PVC) as a carbon source was added to improve electrochemical properties. When the PVC was added after $Li_4Ti_5O_{12}$ formation, the spinel structure was well synthesized and it was confirmed by X-ray diffraction (XRD) experiments. When the carbon material was added before the synthesis and the heat treatment was performed, it was confirmed that a material having a different crystal structure was synthesized even when a small amount of carbon material was added. In the case of $Li_4Ti_5O_{12}$ without the carbon material, the electrical conductivity value was about $10{\mu}S\;m^{-1}$, which was very small and similar to that of the nonconductor. As the carbon was added, the electrical conductivity was greatly improved and increased up to 10,000 times. Electrochemical impedance spectroscopy (EIS) analysis showed that the size of semicircle corresponding to the resistance decreased with the carbon addition. This indicates that the resistance inside the electrode is reduced. According to the Cyclic voltammetry (CV) analysis, the potential difference between the oxidation peak and the reduction peak was reduced with carbon addition. This means that the rate of lithium ion insertion and deinsertion was increased. $Li_4Ti_5O_{12}$ with 9.5 wt% PVC added sample showed the best properties in rate capabilities of $180mA\;h\;g^{-1}$ at 0.2 C-rate, $165mA\;h\;g^{-1}$ at 0.5 C-rate, and $95.8mA\;h\;g^{-1}$ at 5 C-rate.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.723-735
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• 1998

Background : Vitamin C has been reported to have a role in the decrease of airway hyperresponsiveness in animal models. This data is based on some metabolic actions of vitamin C, such as promotion of histamine degradation, producing more $PGE_2$ than $PGF_{2\alpha}$ in cyclooxygenase pathway, decrease of smooth muscle contraction, and acting as reducing agent of oxidant. It has been also known that heavy smokers have lower blood levels of vitamin C than nonsmokers and this deficiency in heavy smokers have been explained by several mechanisms, such as increased oxidation by oxidants and free radicals, increased biosynthesis of catecholamine and serotonin released by nicotine, and inadequate dietary intake. In this study, We attempted to assess effect of vitamin C on bronchial hyperresponsiveness in heavy smokers who have bronchial hyperresponsiveness and role of vitamin C on bronchial hyperresponsiveness. Method: To assess acute effect of vitamin C on airway hyperresponsiveness, blood sample for vitamin C level and spirometry, methacholine challenge test were done in 17 smokers and 8 nonsmokers, and one hour after oral administration of vitamin C 3 g, blood sample for vitamin C level and spirometry, methacholine challenge test were repeated. To assess chronic effect of vitamin C on airway hyperresponsiveness, after daily administration of vitamin C 1 g for one week in 17 smokers, blood sample for vitamin C level and spirometry, methacholine challenge test were done. To assess role of vitamin C, after oral administration of vitamin C 3 g plus indomethacin 100 mg in 12 of 15 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were done and after oral intake of indomethacin 100 mg in 12 smokers who were reactive to methacholine challenge test, spirometry and methacholine challenge test were repeated. Result: There were no significant differences in whole blood vitamin C levels between smokers($1.17{\pm}0.22$ mg/dL) and nonsmcikers($1.14{\pm}0.19$ mg/dL) (p>0.05). Fifteen of the 17 smokers(88.2%) were reactive to methacholine challenge test and 10 of the 15 smokers who were reactive to methacholine challenge test were less than 8 mg/dL in $PC_{20}FEV-2$, and 7 of the 8 nonsmokers(87.5%) were nonreactive to methacholine challenge test There were significant decrease in bronchial responsiveness after oral administration of vitamin C 3 g in 13 of the 15 smokers who were reactive to methacholine challenge test This significant decrease persisted with maintenance daily administration of 1 g for one week. $PC_{20}FEV-2$ were not correlated to vitamin C levels in smokers. After oral administration of indomethacin 100 mg, significant reduction of bronchial responsiveness that occured after oral administration of vitamin C 3 g in smokers were attenuated. Conclusion: Although there were no significant differences in whole blood vitamin C levels between smokers and nonsmokers. heavy smokers have significant increase in bronchial responsiveness than nonsmokers. This bronchial hyperresponsiveness of heavy smokers can be attenuated by vitamin C supplement. Disappearance of vitamin C effect by indomethacin supplement may suggest that vitamin C exert its effect via alteration of arachidonic acid metabolism.