• Food Science of Animal Resources
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• v.35 no.1
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• pp.41-49
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• 2015

This study was performed to assess the antioxidant activity of Allium hookeri root extract (AHE) on lipid oxidation of raw sulfur-fed pork patties for 14 d of refrigerated storage. Different concentration of ethanol (0-100%) and time (1-12 h) were applied to determine the extraction condition. Water (0% ethanol) extraction for 1 h was selected as an optimal extraction condition of AHE for the following study showing the highest total phenolic content and total flavonoid content, as well as the strongest antioxidant activity. The 1% AHE (SP1), 3% AHE (SP2), and 0.05% ascorbic acid (SP3) were added into sulfur-fed pork patties against controls; SP0 (sulfur-fed pork patties with no AHE) and P0 (normal pork patties with no AHE). The pH values of P0 and SP0 significantly increased (p<0.05) than others on 14 d and redness of P0 showed the largest decrement during storage. P0 and SP0 showed higher production of conjugated dienes on d 7 than others (p<0.05). Thiobarbituric acid reactive substances (TBARS) values were decreased in proportion to the increased level of AHE on 14 d (p<0.05) resulting in higher TBARS values on P0 and SP0 (p<0.05) and the negative correlation between AHE level and TBARS were also demonstrated (r=-0.910, p=0.001). Therefore, the results suggest that AHE effectively retarded the lipid oxidation rate of sulfur-fed pork patties indicating the potential usage of AHE as a natural preservative.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.3
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• pp.343-348
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• 2013

This experiment was conducted to evaluate the development of T cells in intrauterine growth retarded (IUGR) piglets at different gestational stages, and tentatively explore the relationship between T cells development and the Notch signaling pathway. A total of 18 crossbred (Landrace${\times}$Large white) primiparous sows were mated at similar weights and estruses and euthanized at d 60, 90 and 110 of gestation with six replicates for each time point. One IUGR and one normal fetus were picked from each litter. The T-cell subsets, mRNA expression of Delta-like1, Delta-like4, Jagged1, and Notch2 genes in the thymus were investigated. Compared to normal piglets, $CD3^+CD4^-CD8^+$ cells in IUGR fetuses at d 90 was 0.13% lower (p<0.05). At d 110 of gestation $CD8^+$ T cells in IUGR fetuses was 0.19% lower (p<0.05). The percentage of $CD8^+$ T cells was 3.14% lower (p<0.05) of the total T cells in IUGR pigs at d 60. The abundance of Notch2 and Delta-like4 mRNA at d 110 was 20.93% higher and 0.77% (p<0.05) lower, and Delta-like1 mRNA at d 90 was 0.19% (p<0.05) higher compared to normal pigs. These results suggested that normal fetuses had a greater proportion of T-cell subsets at earlier gestation periods, and the Notch signaling pathway was likely partially responsible for these differences to some degree.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.179-186
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• 1974

The followings are some results obtained from a series of experiments for the culture of eels from the elver stage in the laboratory from April 1973 to June 1974. 1. The optimum temperature turned out as 30t in the early stage culture. 2. The exponential curve of growth rate for a ten day period at the temperature between $20^{\circ}C$ and $30^{\circ}C$ was represented by the following equation: $$R=0.0056296\;T^{1.80740}$$ 3. The elvers and small eels that were kept improperly for a long time before this experiment also showed the same growth rate, compared with other healthful eels captured directly from the estuarine areas. 4. Those that showed retarded growth among a group of eels during the culture recovered the normal growth rate if graded out and kept in the other aquarium. 5. Feeding rate was not affected when the content of ammonia was less than 5 ppm, but it decreased by half when the content exceeds 6 ppm. 6, The elimination of fecal stuffs and uneaten dispersed feed was very important for the maintaining the water in quality.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.189-193
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• 2000

Preservative and antimutagenic effects of green tea leaves added Chinese cabbage kimchi (GK1, GK2, GK3, and GK4 : 1, 2, 3 and 4 of green tea leaves (GTL) in proportion of 100 of salted Chinese cabbage were added to kimchi) were compared to those of the Chinese cabbage kimchi without GTL (control kimchi, CK). Fermentation period of GKs was further delayed than that of CK. The initial pH and acidity between GKs an CK were similar, but the time reach optimally ripened status of kimchi (pH 4.3) was different. CK took 6 days, while GK1, GK2, GK3 and GK4 took 6, 10, 12 and 14 days at 10℃, respectively. The growth of Leuconostoc sp. and Lactobacilus sp. in GKs delayed comparing to those in FCK. Among GKs, as the added amount of green tea leaves increased, the growth of lactic acid bacteria was retarded. The antimutagenic effects of juices from GKs and CK were studied against aflatoxin B₁(AFB₁) in the Ames test on Salmonella typehimurium TA100 and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the SOS chromotest using E. coli PQ37. Juices from optimally ripened GKs (pH 4.3) showed 52∼76% inhibition rates against the indirect mutagen, aflatoxin B₁ induced mutagenicity while 49% inhibition rate by CK in the Ames test. Juices from GKs and CK showed 44∼67% and 36% inhibition rate against direct mutagen, MNNG (70 ng/assay) induce mutagenicity in the SOS chromotest. Thus GKs delayed fermentation period of kimchi and exhibited higher antimutagenic activity than CK.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.113-118
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• 2006

The effects of dietary Rhus verniciflua Stokes supplementation (0%, 2%, 4% and 6%/feed) on meat color, water-holding capacity (WHC), lipid oxidation and fatty acid composition in m. longissimus from Hanwoo (Korean cattle) beef during refrigerated storage were investigated. The $L^*$, $a^*$, $b^*$ and $C^*$ values of 4% group were significantly (p<0.05) higher than those of the other groups for 7 days of storage. The $a^*$, $b^*$ and $C^*$ values declined gradually during storage in all of the groups and the decline was more rapid in control group. The metmyoglobin (%) was significantly (p<0.05) increased during storage time in all of the groups, but the 4% group had a lower rate of metmyoglobin accumulation during storage. WHC was significantly (p<0.05) higher in the 2% and 4% groups than in the other groups. The TBARS (thiobarbituric acid reactive substances) value of day 0 was not significantly (p>0.05) different among 4 diet conditions, but the TBARS value after 5 days of storage was significantly (p<0.05) higher in the control group than in other groups. The proportions of C18:1, MUFA, UFA and MUFA/SFA ratio were significantly (p<0.05) higher in the meat from Rhus verniciflua Stokes-supplemented Hanwoo than in the control group. Consequently, the meat from Rhus verniciflua Stokes-supplemented Hanwoo showed higher color stability, WHC, unsaturated fatty acids and retarded lipid oxidation compared to the control meat. In particular, dietary Rhus verniciflua Stokes supplementation with 4% extended storage life compared to the other groups.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.987-994
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• 1997

To investigate the effects of n-3 fatty acids on breast cancer, MDA-MB231 human breast cancer cells were cultured in the presence of $\alpha$-linolenic (LNA), eicosapentaenoic(EPA), and docosahexaenoic acid (DHA) at a concentration of 0.5$\mu\textrm{g}$/ml in serum -free IMM medium. Cell growth was monitored and thiobarbituric acid reactive substances (TBARS), $\alpha$-tocopherol contents, and oncogene expression were measured. To compare the effects of n-3 fatty acids with other types of fatty acid, steraic (STA), olieic(OA). linoleic acid(LA) were used. After one day , cell growth was retarded most highly when DHA was in the medium. Cellular TBARS level measured after three days of culture was the highest with DHA in the medium and was also increased by LNA and EPA, compared with STA, OA and LA. Alpha-tocoopherol contents of cells were decreased by DHA but only modestly. There was non significant difference in $\alpha$-tocopherol contents in cells cultured in the presence of the other fatty acids. northern blot hybridization carried out with cells cultured during 24 hours showed that levels of erbB-2 mRNA were not altered by six different fatty acids in the medium but those of c-myc were transiently decreased in the early period by both n-6 and n-3 polyunsaturated fatty acids. The level of tumor suppressor gen p53 mRNA , however, was increased by DHA with time. It is concluded that the cytotoxicity of lipid peroxide and increased expression of tumor suppressor gene p53 are at least partly responsible for the inhibitory effect of DHA on growth of breast cancer cells.

• Polymer(Korea)
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• v.24 no.6
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• pp.777-786
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• 2000

Fire resistance and thermal stability of polypropylene composite systems were investigated by using several halogenated fire-retardants such as decabromodiphenyl oxide (DBDPO) and chlorinated paraffin wax (CPW). The fire resistance of composite systems was thoroughly examined by measuring limited oxygen index (LOI, ASTM D2863, ISO 4589) and characteristic properties of cone calorimetry(ASTM E1354, ISO 5660) heat release rates (HRR), time to ignition (TTI), total heat release (THR), effective heat of combustion (EHC), mass loss rates, etc. Comparing the cone calorimetry experimental results of the halogen flame retardants, DBDPO exhibited twice higher efficiency than CPW in polypropylene systems, and the LOI also showed similar trends to cone calorimetry. The thermo-oxidative stability of the composite systems was increased about 30-5$0^{\circ}C$ in thermogravimetry analysis.Collectively, the combustion, extinction and thermally-stable characteristics of flame retardants were identified in this study.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.505-514
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• 2000

The carburizing behavior and fatigue properties of the plasma carburized low carbon Cr-Mo steel(0.176C-1.014Cr-0.387Mo) have been investigated. The effective case depth in plasma carburized steel increased up to 50% in comparison with that of gas carburizing, and this case depth increased with the increasing surface carbon content. With increasing time in plasma carburizing, the surface carbon content increased but its increasing rate decreased. Fatigue properties were studied in terms of microstructure, case depth, retained austenite and residual stress near the surface. The fatigue limit of the plasma carburized steel was higher than that of gas carburized one. The initiation of microcracks and initial crack propagation were retarded due to a relatively little surface and internal oxidation layer in plasma carburized steel. Fractography showed the crack initiated at the surface, and transgranular fracture at surface layer was more predominant in plasma carburized steel compared to that of gas carburized steel.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.5
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• pp.260-266
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• 2003

In order to study the interfacial reaction between Nb thin sheet and Fe-C-(Si) alloy with different Chemical compositions, they were cast-bonded. The growth of carbide layer formed at the interface after isothermal heat treatment at 1173K, 1223K, 1273K and 1323K for various times was investigated. The carbide formed at the interface was NbC and the thickness of NbC layer was increased linearly in proportional to the heat treating time. Therefore, It was found that the growth of NbC layer was controlled by the interfacial reaction. The growth rate constant of NbC layer was slightly increased with increase of carbon content when the silicon content is similar in the cast irons. However, as silicon content increases with no great difference in carbon content, the growth of NbC layer was greatly retarded. The calculated activation energy for the growth of NbC layer was varied in the range of 447.4~549.3 kJ/moI with the compositions of cast irons.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1103-1112
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• 2001

The effect of pressure gradients on the hairpin structures in three different turbulent boundary layers (ZPG : Re(sub)$\theta$=910, FPG : Re(sub)$\theta$=575, APG : Re(sub)$\theta$=1290) has been examined with instantaneous velocity fields obtained in streamwise-wall-normal planes using PIV (particle image velocimetry) method. In the outer layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. The signature pattern of the hairpin consists of a spanwise vortex core located above a region of strong second quadrant fluctuation (u<0 and v>0 : Q2 event) is clearly observed. The formation of packets explains the occurrence of multiple VITA events in turbulent burst. Noticeable differences are found in the average inclination angles of hairpin vortex packets which are 45$^{\circ}$, 35.7$^{\circ}$, and 51.9$^{\circ}$in the case of ZPG, FPG and APG, respectively. It is found that the large, time-varying, irregularly shaped zones with nearly constant streamwise momentum exist throughout the boundary layer. Within the interior of the envelope the spatial coherence between the velocity fields induced by the individual vortices leads to strongly retarded streamwise momentum, explaining the zones of uniform momentum. The formation of the uniform momentum zone is remarkably different with respect to the pressure gradients especially in the logarithmic layer.