• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.405-415
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• 2021

MMBR system has been suggested as a promising system to resolve harvesting problems induced from low settling efficiency of microalgae. And recently, a lot of research on reducing fouling at the MMBR system has investigated focused on EPS in many cases. EPS of microalgae mainly consists of polysaccharides and protein components, and is produced through photosynthesis and nitrogen-carbon metabolic pathways. Especially, P-EPS is one of major compounds which occur membrane fouling phenomenon, as its hydrophobic protein components cause floc formation and cake layer accumulation. And it is already known that almost every microalgae can metabolize P-EPS or Chl-a when nitrogen sources as a substrate is insufficient or exhausted situation. With the above backgrounds, uptake rates of P-EPS or Chl-a by Scenedesmus quadricauda according to the type of carbon source and nitrogen concentration were evaluated in order to verify correlation between carbon source vs P-EPS production, and indeed Scenedesmus quadricauda uses P-EPS or Chl-a when the amounts of nitrogen sourc es in the feed is not satisfied. As a result, it was shown that P-EPS and Chl-a production were increased proportional to nitrogen concentration under organic carbon condition. And especially, the amo unts of P-EPS and Chl-a in the cell were diminished with the nitrogen source becomes insufficient or exhausted. Because P-EPS accelerates fouling at the MMBR system, P-EPS degradation by Scenedesmus quadricauda in order to get nitrogen source may contribute to reducing fouling. About a affects of N-consumed Chl-a to the MMBR fouling, more survey is needed. On the contrary, considering the purpose of MMBR system of this study, i.e. harvesting useful high value microalgae efficiently feeding adequate industrial process wastewater, it seems like difficult to maintain satisfied metabolic activity and to harvest with high yield rate using nitrogen-poor MMBR feed.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.354-362
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• 2009

This study was performed to develop a suitable nutrient solution for standard rose substrate culture in a closed hydroponic system. 1/4, 1/2, 2/3 and 1 strength of the nutrient solution made by Japan National Institute of Vegetable and Tea Science (JNIVT) were supplied. The photosynthesis rate, quality and growth of cut flower were higher in the 1/2 and 2/3 strength of nutrient solution during high and low temperature period. Based on the above results, optimum nutrient solutions (UOS) were composed by nutrientwater (n/w) absorption ratio with 1/2S ($NO_{3^-}N$ 6.8, $NH_{4^-}N$ 0.7, $PO_{4^-}P$ 2.0, K 3.8, Ca 3.0, Mg 1.2, $SO_{4^-}S$ $1.2me{\cdot}L^{-1}$) at high temperature season and 2/3($NO_{3^-}N$ 9.7, $NH_{4^-}N$ 0.8, $PO_{4^-}P$ 2.2, K 5.0, Ca 3.9, Mg 1.5, $SO_{4^-}S$ $1.5me{\cdot}L^{-1}$) at low temperature season. The results of suitability examination showed that the EC level in newly composed nutrient solution (UOS) was more stable than other nutrient solutions due to its large amount of calcium and potassium. The growth of cut flower cultivated with UOS was higher than those of other nutrient solutions. Especially, the yield of cut flowers in UOS nutrient solution increased 1.4 times than that of other nutrient solution treatments. Consequently, the new nutrient solution investigated in this experiment was suitable for rose cultivation in a closed hydroponic system.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.67-78
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• 2007

This study was carried out to monitor feed-nutritional components, toxic heavy metals (Cd, Pb and As) and pesticide residues through three cultivation stages (1st initial culture stage, 2nd mycelial growth stage, and 3rd fruit body-harvested stage) of king oyster mushroom (Pleurotus eryngii) produced by bottle type cultivation and oyster mushroom (Pleurotus osteratus) produced by vinyl bag type cultivation. For both cultivation types, compared with the initial culture, the weight reduction rate in spent mushroom substrates (SMS) after fruit body harvest was 29% for total wet mass, 21～25% for dry and organic matters and 19 ～22% for neutral detergent fiber. Two thirds to 3/4 of organic matter degraded and utilized by mycelia and fruit bodies was originated from fiber, of which the primary source (50～70%) was hemicellulose. The effect of mycelial growth stage on chemical compositional change in culture was little (P>0.05) for bottle type cultivation of king oyster mushroom but considerable (P<0.05) for vinyl type cultivation of oyster mushroom. Culture nutrients uptake by fruit bodies was very active for the bottle type cultivation. Compared with SMS, harvested fruit bodies (mushrooms) contained higher (P<0.05) crude protein, non-fibrous carbohydrate, and crude ash and lower (P<0.05) neutral detergent fiber. Regardless of stages, no culture samples were contaminated with toxic heavy metals and pesticide residues. In conclusion, the increase of fiber (neutral and acid detergent fibers) and indigestible protein contents and the decrease of true protein content in SMS indicated that the feed-nutritional value of SMS was significantly reduced compared with that of the initial culture and they were safe from toxic heavy metals and pesticide residues.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.149-156
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• 2014

The objective of this research was to investigate the influence of bicarbonate ($HCO_3{^-}$) concentrations in nutrient solution on the growth and physiological disorders in mother plants and occurrence of daughter plants in propagation of 'Seolhyang' strawberry (Fragaria ${\times}$ ananassa Duch.). To achieve this, the mother plants were transplanted to coir dust + perlite (7:3, v/v) medium and Hoagland solution was modified to contain 60, 90 (control), 120, 180, and $240mg{\cdot}L^{-1}$ of $HCO_3{^-}$. The symptoms of Fe, Zn and B deficiencies appeared on the mother plants in the $HCO_3{^-}$ of $240mg{\cdot}L^{-1}$ from the 60th day after treatment. The symptoms spread to all plants in the $240mg{\cdot}L^{-1}$ $HCO_3{^-}$ including daughter plants at 90 days after treatment. The$HCO_3{^-}$ concentrations higher than $120mg{\cdot}L^{-1}$ suppressed the growth of mother plants such as leaf number, chlorophyll content, fresh weight and other growth parameters. While the mother plants in $60mg{\cdot}L^{-1}$ $HCO_3{^-}$ produced 23 daughter plants, while mother plants in $240mg{\cdot}L^{-1}$ $HCO_3{^-}$ produced 13 daughter plants. The final pH 126 days after treatment in the $HCO_3{^-}$ of 60, 90, 120, 180 and $240mg{\cdot}L^{-1}$ were 5.4, 5.8, 7.3, 7.9, and 8.3, respectively. The elevation of $HCO_3{^-}$ concentrations in nutrient solution resulted in the decrease of Fe, Mn, Zn and Cu contents of above ground tissue 126 days after treatment. These results indicate that the $HCO_3{^-}$ concentrations higher than $120mg{\cdot}L^{-1}$ inhibited the growth of mother plants and occurrence of daughter plants in vegetative propagation of 'Seolhyang' strawberry.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.626-634
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• 2012

The purpose of this study was to investigate the potential of persimmon vinegar as a functional beverage by analyzing the effects of persimmon vinegar ingestion on the energy substrate during endurance exercise. The healthy male adolescents (n=8) drunk persimmon vinegar ingested trial (PSV) or purified water ingested trial as the control trial (CON) 1 h prior to the exercise with the 60% of maximal oxygen uptake ($\dot{V}O_{2max}$) for 1 h. The exercise intensity was increased to the 80% of $\dot{V}O_{2max}$ and remained until exhaustion. And, the physiological variables, blood components, and amounts of energy oxidation were analyzed. There was no significant difference between trials in physiological variables, and the heart rates after exhaustion were higher in PSV compared to CON. There was no significant difference between trials in blood glucose level, while the blood lactic acids decreased significantly in PSV 30 and 60 minutes after onset of exercise. The free fatty acids concentration increased significantly in PSV from 15 minutes to 60 minutes after onset of exercise. The carbohydrate oxidation decreased significantly in PSV from 45 minutes after exercise and, on the contrary, the fatty acids oxidation increased significantly for the same period. And, fatty acids oxidation was higher in PSV compared to CON even after exhaustion. The respiratory exchange ratio was lower significantly in PSV compared to CON from 30 minutes to 60 minutes after exercise, whereas lower in CON after total exhaustion. The exercise time to exhaustion was 41% longer in PSV compared to CON. These results showed that the persimmon vinegar increase the level of lipids metabolism and decrease sense of fatigue by inhibiting carbohydrate oxidation during moderate intensity exercise, suggesting the possibility of using of persimmon vinegar as exercise functional beverage when ingested 1 h prior to the endurance exercise performance.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.77-92
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• 2014

Fermented foods have often been implicated as causative agents in poisoning due to toxic levels of biogenic amines. Cheese, a milk-based fermented food, is the product most likely to contain potentially harmful levels of biogenic amines, such as tyramine, histamine, putrescine, and so on. Recently, the risk awareness of a dietary uptake of high loads of biogenic amines has increased. Hence, we here review the published literature on several factors known to affect the biosynthesis of biogenic amines and their accumulation in milk-based foods. Furthermore, with regard to risk analysis, we discuss the control of factors related to the synthesis and accumulation of biogenic amines as a means to reduce their incidence in milk-based products, and thus to increase food safety.

• Journal of Life Science
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• v.29 no.5
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• pp.570-579
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• 2019

Diabetes is one of the serious chronic metabolic diseases caused by Westernized eating habits, and the goal of diabetes treatment is to keep blood glucose at a normal level and prevent diabetic complications. This study was designed to investigate the anti-diabetic effects of a mealworm (Tenebrio molitor larva) extract (MWE) on hyperglycemia in an animal model with type 2 diabetes. Diabetic C57BL/Ksj-db/db mice were divided into three groups: diabetic control, rosiglitazone, and MWE. The mice supplemented with MWE showed significantly lower blood levels of glucose and glycosylated hemoglobin when compared with the diabetic control mice. The homeostatic index of insulin resistance was significantly lower in mice supplemented with MWE than in diabetic control mice. MWE supplementation significantly stimulated the phosphorylation of insulin receptor substrate-1 and Akt, and activation of phosphatidylinositol 3-kinase in insulin signaling pathway of skeletal muscles. Eventually, MWE increased the expression of the plasma membrane glucose transporter 4 (GLUT4) via PI3K/Akt activation. These findings demonstrate that the increase in plasma membrane GLUT4 expression by MWE promoted the uptake of blood glucose into cells and relieved hyperglycemia in skeletal muscles of diabetic C57BL/Ksj-db/db mice. Therefore, mealworms are expected to prove useful for the prevention and treatment of diabetes, and further studies are needed to improve type 2 diabetes in the future.