• The Korean Journal of Physiology and Pharmacology
• /
• v.1 no.6
• /
• pp.775-781
• /
• 1997

Although reoxygenation is the best way to salvage hypoxic tissues, reduced oxygen species (ROS) generated during reoxygenation are blown to cause further tissue injuries and the induction of heat shock proteins (HSPs). The present study was undertaken to determine any causal relationship between the severity of hypoxia and the opposite outcomes, either beneficial or detrimental, of the subsequent reoxygenation by measuring the HSP72. To this aim, one group (6 male cats, $2.5{\sim}3.5\;kg$) was subjected to a 5-min episode of hypoventilation (H, ventilation rate: 5/min) for the induction of slight hypoxia and the other group (6 male cats, $2.4{\sim}3.7\;kg$) was subjected to a 5-min episode of apnea (A) for severe hypoxia. Each 3 animals from both groups received a 10-min episode of ventilation with $(95%\;O_2\;(0)$, whereas the remainder did not. After these procedures, all animals were allowed to be ventilated within physiological range for 1, 4, or 8 hours (1H, 1HO, 4H, 4HO, 8H, 8HO, 1A, 1AO, 4A, 4AO, 8A and 8AO groups). Control animals did not receive any manipulation. The arterial blood $pCO_2$ was significantly higher just after apnea than hypoventilation, while $pCO_2$ and pH were significantly lower just after apnea than hypoventilation. Western blot analysis revealed that the magnitude of HSP72 synthesis is larger in 1H, 4H and 8H groups than in 1HO, 4H and 8HO groups, respectively. In contrast, 1AO, 4AO and 8AO groups more induced HSP72 than 1A, 4A and 8A groups, respectively. These results suggest that the reoxygenation is beneficial after slight hypoxia but detrimental after severe hypoxia.

• Korean Journal of Clinical Laboratory Science
• /
• v.51 no.2
• /
• pp.191-197
• /
• 2019

Although auto-adjusting positive airway pressure (APAP) titration at home has several advantages over a CPAP titration in terms of convenience and time saving, there are still concerns as to whether it will show corresponding accuracy when compared to laboratory-based polysomnography (PSG) and CPAP titration. To obtain more evidence supporting home-based auto-titration, APAP titration was performed at home for patients who were presented with OSA on laboratory-based diagnostic PSG followed by CPAP titration. A total of 79 patients were included in the study. They all underwent split-night PSG with CPAP titration, and APAP titration for more than 7 days. The patients with successful titration at both situations were selected. The optimal pressure and apnea-hypopnea index (AHI) of CPAP and APAP titration were compared. The optimal pressure for CPAP and APAP titration were $7.0{\pm}1.8cmH_2O$ and $7.6{\pm}1.6cmH_2O$ (P<0.001), whereas the corresponding AHI were $1.3{\pm}1.5/h$ and $3.0{\pm}1.7/h$ (P<0.001). As a result, the achievement rates of optimal pressure for CPAP and APAP titration were 96.2% and 94.9% (r=-0.045, P=0.688), respectively. The results of this study did not differ with regard to the optimal pressure between CPAP and APAP titration. Overall, CPAP and APAP titrations should be chosen depending on a required situation.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.3
• /
• pp.105-111
• /
• 2017

This study was conducted to evaluate the effects of pH control and ozonation, coagulation on trihalomethanes (THMs) formation during prechlorination of the Nakdong river water. The results showed that lower pH was reduced THMs formation during prechlorination. THMs formation of water lowered pH 9.5 to 9.0, was reduced 18.3% and lowered pH 9.0 to 8.0 was reduced 14%, lowered pH 8.0 to 7.0 was reduced 7%, lowered pH 9.5 to 8.0 was reduced 29%. A low ozone dose ($0.11{\sim}0.48mg{\cdot}O_3/DOC$) before chlorination reduced the yields of THMs (reduced 6~24% in chlorination) compared with no preozonation. Thus the low ozone dose pretreatment is relatively effective plan to reduce THMs formation during chlorination. When ozone 1.0 mg/L, Alum 40 mg/L and sulfuric acid 6 mg/L dosed, The yields of THMs formation was reduced 42% compared with only chlorination. Input of chlorine after preozonation (followed coagulation, pH control) is more effective than only decline pH at a intake station to control THMs formation in a water treatment process. When chlorine 2.5 mg/L was added before coagulation (alum 40 mg/L), THMs formation was reduced 19% by lower pH and decreased 18% by a natural organic matter (NOM) removal compared with only chlorine 2.5 mg/L addition. Because coagulation could induce simultaneously lower pH and NOM removal, THM formation concentration is more effectively lowed than decreasing pH in the Nakdong river water.

• Journal of Animal Science and Technology
• /
• v.51 no.5
• /
• pp.379-386
• /
• 2009

The aim of this study was tofind out the effects of supplementation of vitamin A to the diets of high or low amounts of concentrates for ruminants. In the first experiment, ruminal fermentation patterns with the data of pH, VFA production and cellulose disappearance rates in the rumen in vitro were investigated. In the second experiment, enzyme activities, gas production and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were investigated. Ruminal pH was higher in low amounts of concentrates than in high amounts of concentrates as expected, however, no significant differences were found. Cellulose disappearance rates improved in vitamin A addition particularly in early incubation time (before 24h) and also the production of volatile fatty acids increased in vitamin A addition. These trends were more evident in diets containing high amounts of concentrates than in low amounts of concentrates and it may indicate that vitamin A is more required in the diets of high amounts of concentrates. In the second experiment, gas production, enzyme activities and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were not different between vitamin A added and non-added diets. Ruminococcus flavefaciens may not require additional vitamin A for its own growth.

• Food Science of Animal Resources
• /
• v.23 no.3
• /
• pp.221-226
• /
• 2003

This study investigated the effect of different electrical stunning methods on pH, water holding capacity(WHC), cooking loss(CL), meat color and blood spot rate in broilers. One-hundred and forty broiler chickens were slaughtered by 50, 65 and 90 voltage with the same electrical frequency(255 Hz) and stunning time(5 sec) in commercial abattoir. The ultimate pH of leg muscle and WHC of breast muscle decreased with increasing the stunning voltage. However, there were no significant differences in ultimate pH, WHC and CL of breast muscle, and ultimate pH of leg muscle. Lightness(L*) and yellowness(b*) values of leg muscle stunned with 90V, 255 Hz, 5 sec were higher than those stunned with 50V, 255 Hz for 5 sec(p<0.05). But there were no significant differences in color value on skin, breast and wing muscle. Our experiments showed that change of stunning voltage affected some broiler meat quality parameters. However, further research is necessary to examine the effects of stunning condition on broiler meat quality.

• Korean Journal of Food Science and Technology
• /
• v.36 no.1
• /
• pp.97-104
• /
• 2004

Effects of sub-materials such as, ethanol, mustard, and chitosan, on enzymatic, microbial and physicochemical characteristics of kochujang were investigated during fermentation. Activity of ${\alpha}$-amylase was low in chitosan-added kochujang, whereas those of ${\beta}$-amylase and pretense did not show any remarkable difference. Viable cells of yeast and bacteria decreased in sub-material-added kochujang during fermentation, with yeast counts decreasing more rapidly in ethanol- and mustard-added kochujang than that with chitosan. Consistency of kochujang decreased during fermentation, with the highest consistency observed in ethanol-added kochujang. Oxidation-reduction potential was low in chitosan-added kochujang. Water activity of all kochujang groups decreased during fermentation with the lowest in ethanol-added kochujang. Hunter L-, a-, and b-values of chitosan-added kochujang were higher than other groups, whereas increase in total color difference of low-salt without sub-material group was lowest pH of kochujang was the highest in ethanol-added kochujang, whereas titratable acidity increased remarkably in chitosan-added group. Total sugar and reducing sugar contents of kochujang were high in ethanol-and mustard-added groups, whereas ethanol production decreased remarkably in mustard-added kochujang. Amino nitrogen content was highest in low-salt without sub-material kochujang during late aging period. Ammonia nitrogen content was lower in mustard-added kochujang. After 12 weeks of fermentation, ethanol-added kochujang was more acceptable than mustard-and chitosan-added groups in taste, color, and overall acceptabilities.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.5
• /
• pp.388-392
• /
• 2000

To improve functionality and characteristics of alginate from the sea tangle, Laminaria japonicus, partially depolymerized alginates (HAG-10, average molecular weight 10,000; HAG-50, average molecular weight 50,000; HAG-100, average molecular weight 100,000) were obtained with hydrolysis of alginate by heating at $12^{\circ}C$. Effects of the depolymerization on physicochemical properties were investigated in the antimutagenicity and binding capacity of cholesterol, glucose and cadmium. In the Ames mutagenicity test using Salmonella typhimurium TA 100, HAG-10, HAG-50, HAG-100 and intact alginate reduced effectively the mutagenicities induced by aflatoxin $B_1 (AFB_1)$ and N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and HAG-10 showed the strongest antimutagenicity among the tested samples. The binding capacity of cholesterol, glucose and cadmium at different pH in vitro depended highly on molecular weight of alginate, and the changes in binding capacity at different pH was not different.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.3
• /
• pp.553-559
• /
• 2004

This study was carried out to estimate the effects of glucono-$\delta$-lacton (GDL) on prolongation of shelf-life on Kimchi. Final concentration of added GDL was determined 0.3% according to the result of sensory evaluation. Chemical characteristics and microbiological parameters were monitored during fermentation at 1$0^{\circ}C$. GDL Kimchi showed the initial sharp decrease in pH and gradually increase of pH due to osmotic pressure and then the pH of GDL Kimchi was slowly decreased compared with that of control Kimchi during fermentation. The acidity of control Kimchi was markedly increased around pH 4.5 by growth of microorganism. Otherwise, GDL Kimchi showed that t]le formation of organic acids was slow and little amount compared with that of control Kimchi. HPLC analysis showed oxalic acid, lactic acid, acetic acid, malic acid and succinic acid appeared by fermentation. The production of lactic acid changed a lot in control Kimchi, where as little in GDL Kimchi. Growth of L. mesenteroides at initial stage of Kimchi fermentation was remarkably inhibited by adding 0.3% GDL. It retarded also the growth of L. Plantarum and L. breuis at late stage of Kimchi fermantation and led to reduce the softening of texture and retard over ripening of Kimchi. Tn sensory evaluation of Kimchi, GDL Kimchi showed the similar characteristics to the control Kimchi. This result suggested that GDL can be successfully used for the prolongation of shelf-life and sensory evaluation on Kimchi.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1992.05b
• /
• pp.26-27
• /
• 1992

The effect of activation and electroless nickel plating conditions on contact properties were investigated for selective electroless nickel plating of Si farers in order to obtain an optimum condition of contact hole filling. According to RCA prosess, p-type si 1 icon (100) surface was cleaned out and activated. The effects of temperture, DMAB concentration, time, and stirring iwere investigated for activation of p-type Si(100) surface. The optimal activation condition obtained was 0.5M HF, 1mM PdCl$_2$, 2mM EDTA, 7$0^{\circ}C$, 90sec under ultrasonic vibration. In electroless nickel plating, the effect of temperature, DMAB concentration, pH, and plating ti me were studied. The optimal plating condition found was 0. 10M NiS0$_4$.$H_2O$, 0.lIM Citrate, pH 6.8, 6$0^{\circ}C$, 30 minutes. The contact resistence of fi]ms wascomparatively low. It took 30 minutes to obtain 1$\mu$m thick film with 8$\mu$M DMAB concentration. The film surface roughness was improved with increasing temperature and decreasing pH of the plating solution. The best quality of the film was obtained with the condition of temperature 6$0^{\circ}C$ and pH 6.8. The micro-victors hardness of film was about 600Hv and was decreased wi th increasing particle size of plating layer.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.2
• /
• pp.184-190
• /
• 2005

A new VFAs production process from sewage sludge using Fenton's oxidation was investigated. Optimum concentrations of $H_2O_\;and\;Fe^{2+}$ as well as optimum reaction temperature for VFAs production were studied. In the presence of $Fe^{2+}$ as catalyst, the VFAs formation rate increased about 4 times compared to $H_2O_2$ oxidation process without $Fe^{2+}$. Optimum concentrations of $H_2O_2$ and $Fe^{2+}$ were 0.62 M and 0.007 M, respectively. VFAs formation reaction proceeded rapidly within 1 min and VFAs formed degraded partly to acetic acid and $CO_2$, which exhibited series reaction characteristics. Based on the economic aspect, reaction temperature of $25^{\circ}C$ and 10 min of reaction time were thought to be proper reaction conditions. The effect of initial pH in the range of $3{\sim}6.3$ on the VFAs formation was not observed.