• Korean Journal of Food Science and Technology
• /
• v.36 no.2
• /
• pp.283-287
• /
• 2004

Persimmons suffer from such physiological disorders as flesh softening, peel blackening, and flesh browning, which occur rapidly particularly when exposed to ambient temperature after storage at low temperature, In this study causes of these disorders were examined in terms of respiration and ethylene production of the fruits. Jelly-like flesh softening, considered as symptom of chilling injury, rapidly developed within 3 days of exposure to ambient temperature without modified atmosphere (MA) packaging after low temperature storage. Disorder development was more suppressed at $30^{\circ}C$ than at $20^{\circ}C$; such temperature dependence is closely connected to ethylene production rate of fruits at both temperatures. Inhibition of ethylene production through MA packaging effectively reduced disorder development, which indicates ethylene production is closely related to jelly-like flesh softening disorder. Development of black-staining on peels occurs in fruits exposed directly to ambient temperature, but not in those packaged with thick PE-film. Flesh browning developed only under anaerobic respiration condition of high temperature and MA packaging with thick PE film, and occurred at quick reduction of available oxygen inside MA package at high temperature.

• Journal of Bio-Environment Control
• /
• v.19 no.1
• /
• pp.49-54
• /
• 2010

The study was conducted to compare the postharvest physiology and storability of fresh cut paprika fruits classified by normal, blossom end rot(BER), and misshapen (or knots) fruit. Some disordered paprika fruits that were produced frequently during high temperature season in highland, were sorted out to non-marketable products. These fruits are mostly wasted, but some of them may be used for fresh cut. The respiration rate of fresh cut paprika fruits was lower and ethylene production rate was higher in normal fruits than in disordered fruits, but there was no significant difference. The fresh-cut paprika fruits were stored in MAP conditions at $4^{\circ}C$, $9^{\circ}C$ and room temperature in 25 ${\mu}m$ and 50 ${\mu}m$ thickness ceramic film packaging. The fresh weight of fresh cut paprika fruits decreased below to 1.1% regardless of fruit types, but the fresh weight loss increased in thinner packaging materials and lower storage temperatures. There were not significant different carbon dioxide and oxygen contents in MAP of all fruit types, while $4^{\circ}C$ storage temperature treatment and 25 ${\mu}m$ thickness ceramic film treatment had lower carbon dioxide and higher oxygen contents. Moreover, the carbon dioxide and oxygen contents were changed rapidly at 9 days in $4^{\circ}C$ storage and at 6 days in $9^{\circ}C$ storage when the visual quality of fresh cut decreased dramatically. The ethylene concentration of packages was below 7 ${\mu}l{\cdot}l^{-1}$ in all treatments during storage, while the treatments of thinner packaging material and lower storage temperature showed lower ethylene concentration. The fresh cut of disordered fruits showed less visual quality than normal fruit treatment in both $4^{\circ}C$ and $9^{\circ}C$ storage temperatures, but there was no significant difference. The value of $4^{\circ}C$ treatment that measured 12 days in storage was higher than $9^{\circ}C$ treatment that measured 9 days in storage. The results suggest that the disordered fruits may be used to fresh cut product without any concerns that they will decreased the value of commodities more quickly than the fresh cut made of marketable paprika fruits. As the fresh cut paprika fruits stored in MAP condition, the more effective storage temperature is $4^{\circ}C$ that may have induced chilling injury a whole fruit of the paprika.

• Journal of Animal Reproduction and Biotechnology
• /
• v.34 no.1
• /
• pp.10-19
• /
• 2019

Morphology of cumulus-oocyte-complexes (COCs) at germinal vesicle (GV) stage as one of the evaluation criteria for oocyte maturation quality after in vitro maturation (IVM) plays important roles on the meiotic maturation, fertilization and early embryonic development in pigs. When cumulus cells of COCs are insufficient, which is induced the low oocyte maturation rate by the increasing of reactive oxygen species (ROS) in porcine oocyte during IVM. The ROS are known to generate including superoxide and hydrogen peroxide from electron transport system of mitochondria during oocyte maturation in pigs. To regulate the ROS production, the cumulus cells is secreted the various antioxidant enzymes during IVM of porcine oocyte. Our previous study showed that Mito-TEMPO, superoxide specific scavenger, improves the embryonic developmental competence and blastocyst formation rate by regulating of mitochondria functions in pigs. However, the effects of Mito-TEMPO as a superoxide scavenger to help the anti-oxidant functions from cumulus cells of COCs on meiotic maturation during porcine oocyte IVM has not been reported. Here, we categorized experimental groups into two groups (Grade 1: G1; high cumulus cells and Grade 2: G2; low cumulus cells) by using hemocytometer. The meiotic maturation rate from G2 was significantly (p < 0.05) decreased (G1: $79.9{\pm}3.8%$ vs G2: $57.5{\pm}4.6%$) compared to G1. To investigate the production of mitochondria derived superoxide, we used the mitochondrial superoxide dye, Mito-SOX. Red fluorescence of Mito-SOX detected superoxide was significantly (p < 0.05) increased in COCs of G2 compared with G1. And, we examined expression levels of genes associated with mitochondrial antioxidant such as SOD1, SOD2 and PRDX3 using a RT-PCR in porcine COCs at 44 h of IVM. The mRNA levels of three antioxidant enzymes expression in COCs from G2 were significantly (p < 0.05) lower than COCs of G1. In addition, we investigated the anti-oxidative effects of Mito-TEMPO on meiotic maturation of porcine oocyte from G1 and G2. Meiotic maturation and mRNA levels of antioxidant enzymes were significantly (p < 0.05) recovered in G2 by Mito-TEMPO ($0.1{\mu}M$, MT) treatment (G2: $68.4{\pm}3.2%$ vs G2 + MT: $73.9{\pm}1.4%$). Therefore, our results suggest that reduction of mitochondria derived superoxide by Mito-TEMPO may improves the meiotic maturation in IVM of porcine oocyte.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.11
• /
• pp.1186-1192
• /
• 2005

The relationship between bacteria and anaerobic archaea, sludge yield coefficient and nitrogen removal rate were investigated in intermittent aeration systems(I/A) with added archaea, I/A and conventional activated sludge system. As the archaea solution was added to the I/A reactor, organic removal rate as well as nitrogen removal rate increased. Also, sludge production rate in I/A system added the archaea was maintained lower than other systems because sludge yield coefficient was decreased due to the role of anaerobic archaea such as anaerobic degradation of organics. The experimental data supported the possibility of symbiotic activated sludge system with anaerobic archaea under intermittent aeration, leading to the enhanced nitrogen removal. Crucial results to be presented are: 1) specific oxygen utilization rate(SOUR) of the I/A-arch system was $2.9\;mg-O_2/(g-VSS{\cdot}min)$. SOUR and nitrification rate of the sludge from the I/A-arch system was higher than those from the I/A and A/S reactors. 2) Removal efficiencies of $TCOD_{Cr}$ in the I/A-arch, I/A and A/S reactors were 93, 90 and 87%, respectively. 3) Nitrification occurred successfully in each reactor, while denitrification rate was much higher in the I/A-arch reactor. Efficiencies of TN removal in the I/A-arch, I/A and A/S reactors were 75, 63 and 33%, respectively.

• Korean journal of applied entomology
• /
• v.56 no.2
• /
• pp.147-152
• /
• 2017

Heart contraction is essential for insect hemolymph circulation, in which various physiological changes need control of the heart contraction. Thus, interruption of heartbeats intimidate insect survival. Chlorine dioxide induces release of reactive oxygen species (ROS), which has been regarded as the main insecticidal agent. This study analyzed the effect of chlorine dioxide on heartbeats of the Indianmeal moth, Plodia interpunctella. The larvae have the dorsal vessel on the medial dorsal region in a form of an extending tube from the first thorax to 10th abdominal segment. Dorsal vessel contraction was noticeable between 3rd and 10th abdominal segments, where five heart chambers were observed. Average heartbeat rate was 118.6 beats per min at $25^{\circ}C$. However, the heartbeats varied with ambient temperature. Injection of chlorine dioxide to hemocoel suppressed the heartbeats in a dose-dependent manner. The suppressive effect of chlorine dioxide also increased with exposure time to gas form of the chemical at 100 ppm. However, vitamin E (an antioxidant against ROS) treatment significantly rescued the larvae treated with chlorine dioxide in the heart contraction activity. These results suggest that chlorine dioxide negatively influences on the heart contraction of P. interpunctella via its production of ROS.

• The Korean Journal of Malacology
• /
• v.32 no.3
• /
• pp.149-155
• /
• 2016

To assess the effects of environmental factors on the sustainability of cultured ark shell Scapharca broughtonii production, we investigated the habitat characteristics of shellfish-farming bays (Gangjin Bay, Yeoja Bay, Keoje Bay and Deukryang Bay). We measured the physiochemical parameters (temperature, salinity, dissolved oxygen, nutrients, chemical oxygen demand and Chlorophyll a) and the geochemical characteristics (chemical oxygen demand, ignition loss, C/N ratio and C/S ratio). Surface sediments were collected from several shellfish-farming bays to examine the geochemical characteristics of both the benthic environment and heavy metal pollution. The grain sizes for Gangjin Bay, Yeoja Bay and Keoje Bay were similar, at the ratio of silt and clay in comparison with Deukryang bay of it. The C/N ratio was more than 5.9, reflecting the range arising from the mix of marine organisms and organic matter. The C/S ratio (more than 4.2) showed that the survey area had anoxic or sub-anoxic bottom conditions. The index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. We suggested that the growth of ark shell Scapharca broughtonii in the shellfish-farming bay was effected by the various environmental conditions.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2002.11a
• /
• pp.171-184
• /
• 2002

Approx. 200,000 bpd vacuum residue oil is produced from oil refineries in Korea. These are supplying to use asphalt, high sulfur fuel oil, and upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435-500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER(Korea Institute of Energy Research) are studing on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature : 1,100~1,25$0^{\circ}C$, reaction pressure : 1~6kg/$\textrm{cm}^2$G, oxygen/V.R ratio : 0.8~0.9 and steam/V.R ratio : 0.4-0.5. Experimental results show the syngas composition(CO+H$_2$) : 85~93%, syngas flow rate : 50~110Mm$^3$/hr, heating value : 2,300~3,000 ㎉/Nm$^3$, carbon conversion : 65~92, cold gas efficiency : 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.

• Journal of Energy Engineering
• /
• v.12 no.1
• /
• pp.49-57
• /
• 2003

Approx. 200.000 bpd vacuum residue oil is produced from oil refineries in Korea, and is supplied to use asphalt, high sulfur fuel oil and for upgrading at the residue hydro-desulfurization unit. Vacuum residue oil has high energy content, however its high sulfur content and high concentration of heavy metals represent improper low grade fuel. To meet growing demand for effective utilization of vacuum residue oil from refineries, recently some of the oil refinery industries in Korea, such as SK oil refinery and LG Caltex refinery, have already proceeded feasibility study to construct 435~500 MWe IGCC power plant and hydrogen production facilities. Recently, KIER (Korea Institute of Energy Research) are studying on the Vacuum Residue gasification process using an oxygen-blown entrained-flow gasifier. The experiment runs were evaluated under the reaction temperature: 1.100~l,25$0^{\circ}C$, reaction pressure: 1~6 kg/$\textrm{cm}^2$G, oxygen/V.R ratio: 0.8~0.9 and steam/V.R ratio: 0.4~0.5. Experimental results show the syngas composition (CO+H$_2$): 85~93%, syngas flow rate: 50~l10 Nm$^3$/hr, heating value: 2,300~3,000 k㎈/Nm$^3$, carbon conversion: 65~92, cold gas efficiency: 60~70%. Also equilibrium modeling was used to predict the vacuum residue gasification process and the predicted values were compared reasonably well with experimental data.

• Clinical and Experimental Reproductive Medicine
• /
• v.32 no.4
• /
• pp.301-314
• /
• 2005

Objective: Rebamipide is a propionic acid derivative that has an action of the inhibition of superoxide production and removal of hydroxyl radical with the sperm incubation and cryopreservation. In the present study, to investigate whether rebamipide is useful to treat male infertility and sterility, the author observed the antioxidative effects in patient with male infertility and also examined its absorption and distribution in rat genital organ. Methods: To measure the distribution of rebamipide in reproductive organ in the rat, carbon indicated rebamipide, $^{14}C-OPC-12759$, was orally administered to 10 Spraque-Dawley rats and its organ concentration in serum, liver, kidney, stomach, duodenum, colon, urinary bladder, seminal vesicle, epididymis and testicle were measured each time after 0.5, 1, 2, 4, 8 and 24 hours by using HPLC fluorescent method. The concentrations in semen were measured by HPLC fluorescent method in a sample of 50 infertile males who took 900 mg of rebamipide daily for 3 months. To measure the antioxidative effect and fertility rate for 3 months, each month before and after the treatment, sperm motility, vitality, the oxygen free radical formation, level of peroxidation, fetilizing capacity of semen sample which were obtained from infertile male patients by masturbation after at least 48 hours abstinence were analyzed by computer assisted semen analyzer, eosin-nigrosin stain, chemiluminescence, thiobarbituric acid method and hypo-osmotic swelling test. Simultaneously in a sample that wanted baby, both pregnancy and delivery were researched. Results: The $^{14}C-OPC-12759$ concentration in the body of white rats was highest in gastrointestinal organ like stomach, smal intestine and duodenum and followed by genital organ like seminal vesicle, testis and epididymis. The rebamipide concentration in semen of infertile males was $220.77{\pm}327.84ng/mL$ (SD) which showed a large deviation but it was higher than serum which was $126{\pm}76ng/mL$ (SD). In the infertile males, after the treatment with rebamipide, the level of seminal reactive oxygen species (ROS) and lipid peroxidation have significantly decreased in duration of the treatment (p<0.05) and sperm vitality and fertilizing capacity except sperm motility significantly improved on post treatment of 2~3 months (p<0.05). Out of the 41 cases who hoped for pregnancy, 15 cases (36.6%) became pregnant and 12 cases had childbrith, 2 cases had miscarriage and one case is ongoing. The side effect was observed in 1 case (2%) which experienced diarrhea but it was lost spontaneously. Conclusions: We conclude from this study that rebamipide showed relatively high tendancy of absorption and excretion in the genital organ. In infertile males who had elevated ROS in semen, by specifically inhibiting the cell damage from the antioxidation, a way to preserve sperm motility, vitality and fertilizing capacity was confirmed.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.7 no.4
• /
• pp.159-163
• /
• 2004

This study was performed to estimate the water quality of pH, salinity, dissolved oxygen, ammonium and sulfur hydroxides of sediment in shrimp aquaculture farms of Southwestern coastal of Korea from June to September, 2003. We surveyed the status of water quality and achieved the improve water and sediment quality to restraint the production of ammonium and sulfur hydroxides from sediment of shrimp aquaculture farms. The concentrations of dissolved oxygen increased from noon to the evening for 6 hour and decreased to 2.98 ppm at six o'clock in the next morning and increased repeatedly, even though DO level has a different level in sunny day and cloudy day. This results suggest that the most importance time of the control of DO in shrimp aquaculture farm is next early morning and if the DO concentration increased continuously which may be growing up the concentrations of NH₄/sup +/ and H₂S. The measured of pH and salinity were suitable to growth of shrimp. However, the level of ammonium and sulfur hydroxides produced from the sediments of shrimp aquaculture farms were 2.30 ppm and 0.075 ppm, respectively, which are exceeded to the concentration of guide line for the growth of shrimp. In the results of this study, we found it difficult to improve the water quality using of the present frame of shrimp aquaculture farms. Then, we can improved water quality of DO, NH₄/sup +/ and sediment quality of ORP, H₂S and also achieved down to the rate of shrimp fatal by changed the frame of shrimp aquaculture farms in the scale of laboratory.