• Journal of Life Science
• /
• v.26 no.1
• /
• pp.83-90
• /
• 2016

This study was investigated the improvement effects of Ledebouriella seseloides (LS) ethanol extracts on lipid parameters in an ovariectomized animal model. Sixty, nine-week old female Sprague Dawley rats were randomly assigned to four groups as follows: sham-operated rats (SHAM), ovariectomized rats (OVX-CON) and ovariectomized rats that were treated with LS ethanol extracts (50 mg/kg/day and 200 mg/kg/day, respectively). The diets were fed to the rats for six weeks after their operation. The total-cholesterol and triglyceride contents on serum increased in the OVX-CON group compared to the SHAM group, but supplementation with the LS extract caused these factors to decrease. Notably, the serum LDL-cholesterol concentration in the supplemented 200 mg/kg/day LS ethanol extract group was significantly more reduced than the OVX-CON group. In addition, the platelet aggregation ability was lower in groups treated with LS than in the OVX-CON group. The alkaline phosphatase (ALP) activity was lower in the LS extract group compared to the OVX-CON group. Collagen content, in bone and cartilage, were reduced by ovariectomy, but the supplemented LS extract groups exhibited higher concentrations in their bones. According to these results, the improvement effects of LS extract on serum lipid parameters and osteogenesis in ovariectomized rats were illuminated.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.476-481
• /
• 1997

For the effect of water-soluble degraded chitosan on the shelf-life of tofu, sterilized distilled water, 0.5% degraded chitosan, 0.5% fumaric acid and 0.5% lactic acid used as an tofu-immersion solutions were investigated by microbial counts, pH, and turbidity during the periods of storage at $4^{\circ}C$. After 2 weeks storage, total aerobic microbial counts in tap water and sterilized distilled water used as an immersion solution were $3.8\;{\times}\;10^8$ and $1.8\;{\times}\;10^8\;CFU/mL$, respectively. In 0.5% fumaric acid and 0.5% lactic acid immersion solutions, the microbial counts were around $10^7\;CFU/mL$ after 2 weeks while the microbial population in 0.5% water-soluble degraded chitosan were, however, $1.6\;{\times}\;10^5\;CFU/mL$ after 2 weeks and $1.7{\times}10^7\;CFU/mL$ after 3 weeks. The lag phase of initial contaminated microbes in 0.5% degraded chitosan solution was longer than those of other treatments. The addition of 0.5% fumaric acid and 0.5% lactic acid decreased the initial pH to pH 5.0, while those of tap water, sterilized distilled water and 0.5% degraded chitosan stabilized the immersion solution at around pH 7.2. All initial pH values were decreased during storage and then slowly increased as storage time was increased. The turbidities in all treatments were increased during storage, but the addition of 0.5% degraded chitosan showed the lowest change, compared to other treatments, showing that the water-soluble degraded chitosan has a good antimicrobial effect and has a potential use to extend the shelf-life of tofu product.

• Journal of Korea Port Economic Association
• /
• v.37 no.2
• /
• pp.73-89
• /
• 2021

The handysize bulk carriers are capable of transporting a variety of cargo that cannot be transported by mid-large size ship, and the spot chartering market is active, and it is a market that is independent of mid-large size market, and is more risky due to market conditions and charterage variability. In this study, Granger causality test, the Impulse Response Function(IRF) and Forecast Error Variance Decomposition(FEVD) were performed using monthly time series data. As a result of Granger causality test, coal price for coke making, Japan steel plate commodity price, hot rolled steel sheet price, fleet volume and bunker price have causality to Baltic Handysize Index(BHSI) and charterage. After confirming the appropriate lag and stability of the Vector Autoregressive model(VAR), IRF and FEVD were analyzed. As a result of IRF, the three variables of coal price for coke making, hot rolled steel sheet price and bunker price were found to have significant at both upper and lower limit of the confidence interval. Among them, the impulse of hot rolled steel sheet price was found to have the most significant effect. As a result of FEVD, the explanatory power that affects BHSI and charterage is the same in the order of hot rolled steel sheet price, coal price for coke making, bunker price, Japan steel plate price, and fleet volume. It was found that it gradually increased, affecting BHSI by 30% and charterage by 26%. In order to differentiate from previous studies and to find out the effect of short term lag, analysis was performed using monthly price data of major cargoes for Handysize bulk carriers, and meaningful results were derived that can predict monthly market conditions. This study can be helpful in predicting the short term market conditions for shipping companies that operate Handysize bulk carriers and concerned parties in the handysize chartering market.

• The Korean Journal of Ecology
• /
• v.17 no.3
• /
• pp.251-260
• /
• 1994

Nitrification potential bioassay and terpenoid analyses were performed to determine the roles of terpenoid as an inhibitor of nitrification in the Douglas fir (Pseudotsuga menziesii) forests. The effect of terpenoids in the forest floor was also tested by adding $10{\mu}g/ml$ of four terpenoids(${\alpha}-pinene,{\beta}-pinene,{\gamma}-terpinene, and terpinolene) to mineral soils. The amount of terpenoids in the litter was higher than that in the soil and varied over time, but the amount of terpenoids in the soils was relatively constant. The correlation between the amount of terpenoids in the litter and ammonium oxidation was in inverse proportion to that in the mineral layers $(r^2=0.678)$. Inhibition of ammonium oxidation by terpenoids in the litter was always higher than in the mineral layer, but nitrite oxidation was different from the ammonium oxidation. The fact that there was greater nitrate production from ammonium in the mineral layer than in the forest floor layer seems to be due to the less amounts of terpenoids in the mineral layer. The result of the experiment in which four terpenoids were added to the mineral layer suggests that, after some lag time, the four terpenoids were effective in inhibiting ammonium oxidation. However, nitrite oxidation did not appear to be affected by the four terpenoids. Accordingly, all of our results suggested that terpenoids in Douglas fir forests apparently would act as a part of the inhibitors of nitrification.

• Korean journal of food and cookery science
• /
• v.13 no.2
• /
• pp.106-112
• /
• 1997

The effect of low concentrations of allspice (Pimenta dioica L.) in culture broth as an antibacterial agent against Escherichia coli 0157:H7 and Staphylococcus aureus 196E was tested at 35,5 and -20$^{\circ}C$. Tryptic soy broth (TSB) containing 0∼2% (w/v) of allspice was inoculated with 10$\^$5/∼10$\^$6/ cells/$m\ell$ of E. coli and S. aureus and incubated at each temperature. The growth of E. coli was not inhibited at 0.1∼1.0% allspice and growth occured at 2％ allspice but only after a prolonged lag period. Growth of S. aureus was inhibited with increasing concentration of allspice at 35$^{\circ}C$. Growth of S. aureus occured at the presence of 0.1∼0.3% allspice but the viability of S. aureus at 0.5∼2.0% allspice was decreased during storage at 35$^{\circ}C$. During refrigerated storage at 5$^{\circ}C$, inhibition of E. coli and S. aureus was increased with the progress of time and increasing spice concentration. During frozen storage at -20$^{\circ}C$, antibacterial activity of allspice against E. coli was increased with increasing storage time and spice concentration while that activity against S. aureus was effective during early period of storage. There was no major changes in population of S. aureus in TSB with different concentration of spice frozen at -20$^{\circ}C$. Viable counts of E. coli and S. aureus at 0.l％ of allspice was less than that of control during frozen storage.

• Microbiology and Biotechnology Letters
• /
• v.26 no.1
• /
• pp.76-82
• /
• 1998

The feasibility of algae as means of removing nitrogen and phosphorus from secondary treated swine wastewater was studied. Among the tested 7 species of Chlorella vulgaris (UTEX 265), Chlorella sp. GE 21, Botryococcus braunii (UTEX 572), Botryococcus sp. GE 24, Scenedesmus quadricauda, Phormidium sp. GE 2, and Spirulina maxima (UTEX 2342), C. vulgaris was selected for its fast growth and abilities to remove nitrogen and phosphorus and to produce algal biomass from swine wastewater. C. vulgaris grew well at 35$^{\circ}C$, and the optimum initial pH for growth was 8.0. In the effect of light intensity, the growth of C. vulgaris was limited under a light intensity of less than 40 ${\mu}$E/$m^2$/s. The secondary treated swine wastewater contained 58.7 mg/l of total nitrogen and 14.7 mg/l of total phosphorus, and was diluted to 75, 50, and 25% with groundwater to be treated. Nitrogen and phosphorus were removed by C. vulgaris in all diluted swine wastewaters among which the most effective removal was in 75% swine wastewater (swine wastewater:groundwater=3:1). There was a tendency of linear increase in nitrogen and phosphorus removal time with increasing concentration of swine wastewater. Under the optimized culture condition, total nitrogen and total phosphorus were effectively removed to 95.3% and 96.0%, respectively, in 25% swine wastewater after 4-day incubation.

• Korean Journal of Food Science and Technology
• /
• v.37 no.2
• /
• pp.194-198
• /
• 2005

Growth curves of Listeria monocytogenes in modified surimi-based imitation crab (MIC) broth were obtained by measuring cell concentration in MIC broth at different culture conditions [initial cell numbers, $1.0{\times}10^{2},\;1.0{\times}10^{3}\;and\;1.0{\times}10^{4}$, colony forming unit (CFU)/mL; temperature, 15, 20, 25, 37, and $40^{\circ}C$] and applied to Gompertz model to determine microbial growth indicators, maximum specific growth rate constant (k), lag time (LT), and generation time (GT). Maximum specific growth rate of L. monocytogenes increased rapidly with increasing temperature and reached maximum at $37^{\circ}C$, whereas LT and GT decreased with increasing temperature and reached minimum at $37^{\circ}C$. Initial cell number had no effect on k, LT, and GT (p > 0.05). Polynomial and square root models were developed to express combined effects of temperature and initial cell number using Gauss-Newton Algorism. Relative coefficients of experimental k and predicted k of polynomial and square root models were 0.92 and 0.95, respectively, based on response surface model. Results indicate L. monocytogenes growth was mainly affected by temperature and square root model was more effective than polynomial model for growth prediction.

• Korean Journal of Food Science and Technology
• /
• v.36 no.2
• /
• pp.349-354
• /
• 2004

Predictive growth model of Vibrio parahaemolyticus in modified surimi-based imitation crab broth was investigated. Growth curves of V. parahaemolyticus were obtained by measuring cell concentration in culture broth under different conditions ($Initial\;cell\;level,\;1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}\;colony\;forming\;unit\;(CFU)/mL$; temperature, 15, 25 37, and $40^{\circ}C$; pH 6, 7, and 8) and applying them to Gompertz model. Microbial growth indicators, maximum specific growth rate (k), lag time (LT), and generation time (GT), were calculated from Gompertz model. Maximum specific growth rate (k) of V. parahaemolyticus increased with increasing temperature, reaching maximum rate at $37^{\circ}C$. LT and GT were also the shortest at $37^{\circ}C$. pH and initial cell number did not influence k, LT, and GT values significantly (p>0.05). Polynomial model, $k=a{\cdot}\exp(-0.5{\cdot}((T-T_{max}/b)^{2}+((pH-pH_{max)/c^{2}))$, and square root model, ${\sqrt{k}\;0.06(T-9.55)[1-\exp(0.07(T-49.98))]$, were developed to express combination effects of temperature and pH under each initial cell number using Gauss-Newton Algorism of Sigma plot 7.0 (SPSS Inc.). Relative coefficients between experimental k and k Predicted by polynomial model were 0.966, 0.979, and 0.965, respectively, at initial cell numbers of $1{\times}10^{2},\;1{\times}10^{3},\;and\;1{\times}10^{4}CFU/mL$, while that between experimental k and k Predicted by square root model was 0.977. Results revealed growth of V. parahaemolyticus was mainly affected by temperature, and square root model showing effect of temperature was more credible than polynomial model for prediction of V. parahaemolyticus growth.

• Korea journal of population studies
• /
• v.8 no.1
• /
• pp.47-65
• /
• 1985

Three stages of population growth during last forty years affected differently to the labor force and employment in Korea. The first impact of rapid population growth on the labor force occured after the end of World War II. Sudden growth of population due to repartriation and refugees directly increased the labor force. Deteriorating labor market conditions were caused not only by the explosive labor supply but also by the shortage of employment opportunities due to a lack of productive facilities. This severe excess supply of labor continued until the early 196Os. Population growth in the second stage which caused by high fertility during the post Korean War baby boom period induced an eventual increase in the labor supply with time lag of more than fifteen years. Younger persons born during baby boom period were flooded the labor market. Fortunately, job opportunities were expanded more rapidly than the labor force supply because high rates of economic growth and speedy industrialization were continued until the later half of 1970s. Unemployment, therefore, decreased dramatically during this period. The effect of third stage which is characterized as mitigated population growth due to birth control has appeared in the labor market since late 1970s. The growth rate of labor force has been going down and the proportion of younger workers was also been decreasing. From the early 1980s, furthermore, partial disharmony between supply of and demand for the younger workers is closing up. Less educated younger workers who works at low wage are lacking while more educated youngers who want to work at high wage are being excess, because a lot of younger prefer higher education rather than productive job. It is expected that the structural inharmony will be diversified in the future in Korea. The labor force will be changed to middleaged, highly educated and womenized till year 2000, and, after then, to old-aged. On the demand side, industries and jobs will transferred to be labor-saving and soft. These structural changes of labor supply and demand will not matching in time. Aggregate supply of labor force will be steadily increasing more rapidly than aggregate demand for labor until year 2000, and this trend will continue to the first one or two decades of the 2lth century because the persons born dufing the baby boom pariod are being eligible couples in recent. Therefore, conclusion is that appropriate manpower development policy as well as sustained birth control policy is necessary for harmonizing the structural unbalance and the disequilibrium between aggregate labor supply and demand in the future.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.1
• /
• pp.45-51
• /
• 2007

A growth trial (Expt. 1) and an in vitro fermentation experiment (Expt. 2) were conducted to determine the response of growth performance, cecal fermentation characteristics and in vitro gas production to incremental levels of substitution of digestible fiber for lignified fiber in the diet of weaned rabbits. Three diets, formulated by substituting soyhulls (SH; used as digestible fiber source) for soybean straw (used as lignified fiber source) at substitution levels of 0, 25 and 50%, were used in a factorial design. In the growth trial (Expt. 1), increasing levels of SH substitution resulted in a quadratic increase in daily body weight gain rate (p<0.04) and feed conversion efficiency (p<0.02), but in a numerical decrease in dietary DM intake (p=0.15). When SH were included in the diet at 25% substitution level, rabbits had the highest rate of liveweight gain and feed conversion efficiency. As SH substitution level increased, pH values and ammonia-N of cecal contents linearly (p<0.001) decreased, but total VFA concentration linearly (p<0.03) increased. With incremental levels of SH substitution, the percentage of acetate and butyrate linearly (p<0.05) reduced, but the percentage of propionate and minor acids linearly (p<0.03) increased. Increasing the SH substitution levels tended to increase incidence of diarrhea. In the in vitro fermentation experiment (Expt. 2), regardless of origin of substrates fermented, increasing SH substitution level resulted in increased maximal gas production (p<0.001) and shortened gas production lag time, but had no effect on gas production rate (p>0.2). These observations suggest that incrementally feeding SH to rabbits could stimulate their cecal microbial activity, allowing cecal fermentation to shift towards favoring fiber digestion. In conclusion, digestible fiber from soyhulls may partially substitute for more lignified fiber, soybean straw, without having an adverse effect on cecal fermentative and microbial activity and growth performance. For growing rabbits, about 73% of total dietary NDF should be supplied by effective NDF, the remainder could come from digestible NDF, such as soyhulls.