• Development and Reproduction
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• v.17 no.4
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• pp.345-351
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• 2013

This study examines the effects on fertilization rate (FR), hatching rate (HR), and normal individual rate after artificial fertilization using frozen thawed sperm according to the cryoprotectant (DMSO) concentration and the period of cryopreserved sperm of longtooth grouper, Epinephelus bruneus. Performing artificial fertilization using frozen-thawed sperm, after freezing the sperm at different DMSO concentration of 5.0%, 7.5%, 10.0% respectively, FR were (DMSO 5.0%: $99.5{\pm}0.8%$, DMSO 7.5%: $99.5{\pm}0.7%$, and DMSO 10.0%: $99.6{\pm}0.6%$). The results are not significantly different from the control fresh sperm (100%). HR also (DMSO 5.0%: $96.2{\pm}2.3%$, DMSO 7.5%: $95.3{\pm}3.6%$, 10.0%: $96.6{\pm}1.8%$) were not significantly different in each group. The normal individual rate after hatching using with control fresh sperm ($98.4%{\pm}0.5$) and DMSO concentration level of 5.0% ($97.8{\pm}0.1%$) were not significantly different. However, with 7.5% ($97.2{\pm}0.6%$) and 10.0% DMSO concentrations ($95.9{\pm}0.2%$) are lower than the normal individual rate after hatching observed in the control and 5.0% DMSO. Performing artificial fertilization using frozen-thawed sperm at different frozen period (2 days, 2 years, and 3 years), 10% DMSO FR and HR of 3 years (FR; $66.8{\pm}1.8%$, HR: $82.0{\pm}12.9%$) and 2 years (FR; $78.5{\pm}14.8%$, HR: $79.3{\pm}0.6%$) cryopreserved sperm were lower than control (FR; 100%, HR: $91.1{\pm}3.6%$) and 2 days cryopreserved sperm (FR; $99.6{\pm}0.6%$, HR: $96.6{\pm}1.8%$). These results suggest suitable DMSO concentration ranges of cryopreservation sperm for E. bruneus is 5 to 10% and with 2 to 3 years cryopreservation period, cryopreservation sperm can be useful for seed production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1580-1586
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• 2010

This study was conducted to examine antioxidative and physiological activities of water extracts from different parts (flower, leaf, root, and the whole plant) of Taraxacum officinale. The water extracts from different parts were measured to obtain total flavonoids content, total polyphenol content, electron donating ability, SOD-like activity, nitrite-scavenging ability and tyrosinase inhibition effects. Total flavonoids and total polyphenol contents in flower extract were 32.91 mg/g and 49.31 mg/g, respectively, which were much higher than those of any other parts. The electron donating abilities of flower, leaf, the whole plant, and root extracts were 87.07%, 87.66%, 81.06% and 66.20%, respectively at a concentration of 1 mg/mL. The activities increased in a dose-dependent manner. The SOD-like activity of water extracts from different parts showed 9.07~10.97% at a concentration of 1 mg/mL. The nitrite-scavenging abilities of flower and leaf extracts measured at pH 1.2 were 36.34% and 38.16%, respectively at a concentration of 1 mg/mL. Tyrosinase inhibition activity of the leaf extract at a concentration of 1 mg/mL was the highest (34.19%) and that of the whole plant and root extracts was shown to be more than 20%. These results suggest that water extracts from different parts of Taraxacum officinale could be used as an antioxidative functional food source.

• Proceedings of the Korean Environmental Health Society Conference
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• 2001.11a
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• pp.19-29
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• 2001

Nutrients are key environmental factors in marine ecosystem. They limit algal growth when at low concentrations and cause algal bloom when at high contents. They also control the growth and succession of many other biota including bacteria and zooplankton, either directly or indirectly. Nutrient contents therefore affect both the structure and functions of marine ecosystem. To study the contents and distribution of nutrients in Chinese Bohai Sea, two cruise surveys were undertaken in August 2000 (summer) and January 2001 (winter), respectively. A total of 595 water samples were collected from 91 sites. After collection the samples were transported to the laboratory and five nutrients, i.e., nitrate, nitrite, ammonia, phosphate and silicate, were analyzed. The results showed that tile average concentration of total inorganic nitrogen (TIN) in Bohai Sea in winter (6.5293.717 ${\mu}$mol$.$l$\^$-1/) was significantly higher than that in summer (3.717 ${\mu}$mol$.$l$\^$-1/). The phosphorus concentration in winter (0.660 ${\mu}$mol$.$l$\^$-1/) was also significantly higher than that in summer (0.329 ${\mu}$mol$.$l$\^$-1/). Mean silicate concentration in winter (7.858 ${\mu}$mol$.$l$\^$-1/) was not significantly different from that in summer (7.200 ${\mu}$mol$.$l$\^$-1/). Nutrients also varied considerable among different areas within Bohai Sea. TIN concentration in Laizhou Bay (4.444 ${\mu}$mol$.$l$\^$-1/), for example, was significantly higher than those in Bohai Bay (2.270 ${\mu}$mol$.$l$\^$-1/) and Bohai Straight (2.431 ${\mu}$mol$.$l$\^$-1/), which probably reflects tile discharge of large amounts of nitrogen into Laizhou Bay via Yellow River. The nutrients also showed vertical distribution pattern. In summer, nutrients in bottom layer were generally higher than those in surface and medium layers. In winter, however. nutrients in different layers were not significantly different Compared with historic data, TIN contents increased continuously since early 1980s, phosphorus arid silicone contents, nevertheless, fell down to some degree. Based on atomic ratios of different nutrients, nitrogen is still the main limiting factor for algal growth in Bohai Sea.

• Journal of Environmental Health Sciences
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• v.38 no.2
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• pp.105-117
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• 2012

Objectives: This study aimed to assess the concentration of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) in blood and factors controlling their exposure among Koreans. Methods: Study subjects were selected to include 718 members of the general population residing in five metropolitan cities and the Gangwon Province area from August 2008 to January 2009. A questionnaire was administered to investigate lifestyle, socio-demographic characteristics, and other related factors. Blood samples were collected and extracted using solid-phase extraction and anion-exchange methods, and quantified by high-performance liquid chromatograph (HPLC, Agilent 1200 Series) coupled with a Triple Quad LC-MS/MS system (Agilent 6410). Results: Geometric mean concentrations of PFOA and PFOS in the blood were measured as 1.82 and 6.06 ng/ml, respectively. Mean PFOA and PFOS concentrations generally increased with age in both genders. Blood PFOA concentration was significantly different according to such variables as age, family income, residential district, and province. Blood PFOS concentration was significantly different by such variables as gender, age, lifestyle factors such as regular exercise, alcohol consumption, and smoking status. Also, family income, hazardous facilities, job classification, and province contributed significantly to differences in blood PFOS concentration levels. Conclusions: Blood PFOA and PFOS concentrations in Koreans were similar with those found in Japan, the USA, and Germany, but less than those in Australia. PFOA and PFOS exposure seems to be affected by a variety of factors in Korea. Therefore, investigation is required for each factor to assess the relative contribution of different variables.

• Journal of Bio-Environment Control
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• v.17 no.3
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• pp.226-230
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• 2008

A comparison was made of the effect of different packaging materials on storability of mixed sprout vegetables (alfalfa, broccoli, cabbage, radish, and red radish) stored at $8^{\circ}C$. They were packaged by several kinds of films that were 50 fm thickness low-density polyethylene film (PE 50), 50 fm thickness polypropylene film (PP 50), $50{\mu}m$ thickness ceramic film (CE 50), $25{\mu}m$ thickness ceramic film (CE 25), $10\sim13{\mu}m$ thickness polyethylene film (wrap), and polyethylene terephthalate box with ventilation hole (box). The fresh weight of mixed sprouts packaged with different materials decreased below to 2% except box packages that decreased around 7% compared with initial weight. The atmospheres that were developed inside the different materials during storage differed significantly. The carbon dioxide and oxygen concentration of packages were kept properly with 5% in CE 25, but the PE 50 and CE 50 treatments showed higher carbon dioxide and lower oxygen concentration. So the off-flavor of mixed sprouts was more severe in the PE 50 and CE 50 treatment. The ethylene concentration of packages showed lowest in box treatment, followed by PP 50, wrap and CE 25 treatment. The overall quality of mixed sprouts was lower in PE 50 and CE 50 than CE 25 treatment after 10 days storage, supposed to be resulted from highest ethylene concentration and lowest oxygen concentration. Conclusionally, the CE 25 film that showed below 1% fresh weight loss, 5% carbon dioxide, 5% oxygen and below 4 ppm ethylene concentration in package may be a proper packaging material for mixed sprout vegetables.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.225-232
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• 2003

Nutrients and water absorption by Citrus unshiu Marc. cv. Miyagawa Wase were examined using spray type of out-door hydroponics system. Three different concentration levels of nutrient solution were treated to citrus trees to examine nutrient uptake. To do so, concentration and the volume change of nutrient solution was measured for each treatment. By weighing the volume of solution and citrus trees, amounts of water uptake and fresh weight increase were observed periodically. Water uptake by trees increased as tree grew and time elapsed, but was lower at high level of nutrient concentration than the rest, due partly to the reduction in hydraulic conductance and to the sustained high salt concentration. Rapid increase in fresh weight and nutrient uptake occurred from May to July and from August to September. The amounts of nutrient uptake were significantly different among nutrient levels: the higher concentration, the greater uptake by citrus tree. The absorbed amounts of $NO_3$, K and Ca were much higher than those of $NH_4$, S, P, Mg, and Fe. Most mineral contents in leaves were proportional to the concentration of supplied nutrient solutions. From the results of nutrient absorption and contents in leaves at different levels of nutrient solutions, the composition of major elements for citrus nutrient solution can be modified as follows: 27.1, 16.5, 66.0, 80.0, and $24.0mg\;L^{-1}$ for N, P, K, Ca, and Mg, respectively.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.313-321
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• 2005

Based on the result that biological control agent (BCA) increased the dissolved microcystin-LR in a field experiment to control the cyanobacterial bloom (Kim etal., 2005), a laboratory experiment was used to evaluate the effects of dissolved microcystin-LR (MCLR) with different concentrations on abundance, dominance, diversity of phytoplankton community, concentration of chlorophyll a and microcystin concentration in replicated microcosms. The treatments in this laboratory experiment comprised different concentrations of T1 (natural MCLR concentration), T10 (ten times to natural MCLR concentration), and T100 (one hundred times to natural MCLR concentration). MCLR treatment of exclusively Stephanodiscus hantzschii-dominated community in Chonho bridge hardly changed in algal species, but abundance. In Kildong pond, Aulacoseira and Dinobryonrich community was replaced by green algae Scenedesmus-rich community especially in T100 experiment. However, in Yangsoori-Ryukgakji Pond having the highest concentration of initial MCLR, Microcystis aeruginosa was decreased in abundance. Therefore, the treatment of BCA to control M. aeruginosa severely changed the Phytoplankton community in term of algal species, abundance (chlorophyll a) and dissolved microcystin-LR via a high release of MCLR.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.973-979
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• 2005

The present study was planned to examine the effect of different feeding regimens on milk urea concentration and milk protein concentration. The objectives are to describe the diurnal variations of milk urea (MU) concentration and to predict plasma urea (PU) concentration from MU concentration. Six lactating Murrah buffaloes were distributed in two groups and were fed two different diets in a crossover design. The diets consisted of leguminous crops as diet 1 (berseem (Trifolium alexandrinum)+concentrate mixture 1+wheat straw)) and non-leguminous crops as diet 2 (oats (Avana sativa)+concentrate mixture 2+wheat straw). All the diets were isocaloric and isonitrogenous. Each diet was fed to the animals for a period of 28 days, followed by a 10 day gap to obviate the carry over effect of the previous diet and then a switch over to the other diet. Digestibility trials were conducted on the last 7 days of each feeding period. Milk samples were collected on day 3, 7, 10, 14, 17, 21, 24 and 28 of the feeding period and blood samples were collected on the same day at morning within 30 minutes after morning milking. The average milk urea (MU) values (mg/dl) differed significantly (p<0.01) and were 44.83${\pm}$0.62 and 42.53${\pm}$0.73, respectively, for diets 1 and 2. Milk urea concentrations (mg/dl) also varied (p 0.01) among the days of feeding period, but were stabilized after 10th day of feeding period. In contrast, diets and days of feeding period had no significant effect on percent milk protein. Plasma urea concentration showed a significant (p<0.01) positive correlation (r = 0.93) with MU concentration. To predict the PU from MU the following equation was developed 'PU = 10.67${\pm}$0.76${\times}$MU (mg/dl) with $R^2$ = 0.87'. A clear diurnal variation of MU was found with lowered morning value (42.04${\pm}$0.68 mg/dl) than the evening value (45.32${\pm}$0.66 mg/dl). Present findings suggested that MU or PU concentration could be used as an indicator to monitor the feeding strategy. Plasma urea can be predicted from MU, whenever interpretation of milk urea data required consideration of diurnal variation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1079-1087
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• 2005

In this paper, thermal comfort and ventilation performance characteristics in the lecture room with the ventilation system and two different air-conditioning systems, system air-conditioner or fan coil unit, were evaluated by experimental and numerical methods. We compared the measured data with the computational results of the predicted mean vote and carbon dioxide concentration. Additionally the ventilation effectiveness was calculated numerically. From a viewpoint of the uniformity of PMVs in the lecture room, the thermal distribution performance of the system air-conditioner was more effective than the fan coil unit. Carbon dioxide concentration and ventilation effectiveness were barely affected by the type of the air-conditioning system.

• Computers and Concrete
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• v.12 no.5
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• pp.669-680
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• 2013

This paper unveils a new computer based stabilization methodology for automated modeling analysis and its experimental verification for corrosion in reinforced concrete structures under the effect of varying oxygen concentration. Various corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting-drying) have been investigated under controlled laboratory conditions. The results of these laboratory tests were utilized with an automated computer-aided simulation model. This model based on mass and energy stabilization through the porous media for the corrosion process was coupled with modified stabilization methodology. By this coupling, it was possible to predict, maintain and transfer the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual field conditions such as by varying concrete cover depth, relative humidity, water-cement ratio etc. The modeling task has been incorporated by the use of a computer based durability model as a finite element computational approach for stabilizing the effect of oxygen on corrosion of reinforced concrete structures.