• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.317-325
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• 1994

The accuracy of dipyridamole stress/rest $^{99m}Tc$-MIBI myocardial imaging for detection of ischemia depends on reproducible image interpretation. To evaluate the reproducibility of visual assessment, agreement in interpretation among two independent observers, blind-ed to clinical data, was evaluated in SPECT images of 131 patients (94 males, 38 females; mean age $58{\pm}7yr$) with suspected coronary artery disease who underwent both dipyridamole stress/rest $^{99m}Tc$-MIBI myocardial SPECT and coronary angiography. The left ventricle was divided into twenty-nine segments in stress and rest SPECT images and each segment was visually graded according to a five-point scale (segmental score : 0=normal, 1=equivocal, 2=mild decrease, 3=severe decrease and 4=absent uptake). Overall concordance of segmental scoring between the two observers was 80%. The Pear-son's correlation coefficient (r) of the segmental scores for stress and rest images were 0.67 and 0.65, respectively, while the difference in score between the two images showed a correlation of 0.45 (all p<0.001). Agreement between two observers in final SPECT diagnosis as absence or presence of disease was 93%. The degree of agreement in segmental scoring showed no difference between patients with or without agreement as to the presence of disease. Therefore it appeared that cases with inconcordant diagnosis between the 2 observers were mainly due to a difference in individual threshold for interpretating the significance of a particular decreased uptake area rather than to a difference in perceiving the degree of the hypoactivity Thus, establishment of individual optimum thresholds in visual interpretation of myocardial SPECT may be helpful to improve reproducibility and accuracy of scan diagnosis.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.625-634
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• 2004

The objective of this experiment is to study the possibility of lactate dehydrogenase(LDH) enzyme to prevent lactate accumulation in the rumen, For understanding capacity of bacterial LDH in rumen environments, this study was conducted to explore the effects of temperature, pH, VFAs and metal ions on Lactobacillus sp. FFy111-1's LDH activity, and the LDH activation in rumen fluid accumulated lactate. The optimum pH and temperature of LDH were pH 7.5 and 40$^{\circ}C$, respectively. The LDH activity had a good thennostability at range from 30 to 50$^{\circ}C$. The highest pH stability of the enzyme was at ranges from pH 7.0 to 8.0 and the enzyme activities showed above 64% level of non-treated one at pH 6.0 and 6.5. The LDH was inactivated by VFAs treatments but was enhanced by metal ion treatments without NaCl and $CuSO_4$ Especially, the LDH activity was increased to 127% and 124% of its original activity by 2 mM of $BaCl_2$ and $MnSO_4$, addition, respectively. When the acidic rumen fluid was treated by LDH enzyme of Lactobacillus sp. FFy111-1, the lactate concentration in the rumen fluid was lower compared with non-treated rumen fluid(P<0.05). This lactate reduction was resulted from an action of LDH. It was proved by result of purified D,L-LDH addition that showed the lowest lactate concentration among the treatments(P<0.05). Although further investigation of microbial LDH and ruminal lactate is needed, these findings suggest that the bacterial LDH has the potential capability to decrease the lactate accumulated in an acidic rumen fluid. Also, screening of super LDH producing bacteria and technical development for improving enzyme activity in rumen environment are essential keys for practical application.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.301-314
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• 2016

Disused Sealed Radioactive Sources (DSRSs) are stored temporally in the centralized storage facility of Korea Radioactive Waste Agency (KORAD) and planned to be disposed in the low- and intermediate-level radioactive waste (LILW) disposal facility in Gyeongju city. In this study, preliminary post-closure safety assessment was performed for DSRSs in order to draw up an optimum disposal plan. Two types of disposal options were considered, i.e. engineered vault type disposal and rock cavern type disposal which were planned to be constructed and operated respectively in LILW disposal facility in Gyeongju city. Assessment end-point was individual effective dose of critical group and calculated by using GoldSim code. In normal scenario, the maximum dose was estimated to be approximately $1{\times}10^{-7}mSv/yr$ for both disposal options. It meant that both options had sufficient safety margin when compared with regulatory limit (0.1 mSv/yr). Otherwise, in well scenario, the maximum dose exceeded regulatory limit of 1 mSv/yr in engineered vault type disposal and the exposure dose was mainly contributed by $^{226}Ra$, $^{210}Pb$ (daughter nuclide of $^{226}Ra$) and $^{237}Np$ (daughter nuclide of $^{241}Am$). For rock cavern type disposal, even though the peak dose satisfied regulatory limit, the exposure doses by $^{14}C$ and $^{237}Np$ were relatively high above 10% of regulatory limit. Therefore, it is necessary to exclude $^{14}C$, $^{226}Ra$ and $^{241}Am$ for two type of disposal options and additional management such as long-term storage and development of disposal container for those radionuclides should be performed before permanent disposal for conservative safety and security.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.119-126
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• 2011

The study was conducted to investigate the effects of dietary energy and protein levels on productivity and feed cost in crossbred chicks. Experiment was divided into starting (0~5 weeks), growing (6~10 weeks), and finishing (11~14 weeks) periods. Design of feeding trials was 3 ${\times}$ 3 factorial to feed different energy and protein levels for starting (ME 2,950, 3,000, and 3,050 kcal/kg CP 18, 19, and 20%), growing (ME 3,000, 3,050, and 3,100 kcal/kg CP 17, 18, and 19%) and finishing (ME 3,050, 3,100, and 3,150 kcal/kg CP 16, 17, and 18%) periods, respectively. In the starting period, weight gain and FCR was improved by dietary protein level (P<0.05). Interaction effect existed in feed intake and FCR (P<0.05). Weight gain was higher in 3,000 kcal/kg ME treatment than 3,100 kcal/kg ME treatment for growing period (P<0.05). In finishing period, feed intake was significantly decreased in ME 3,150 kcal/kg treatment than the other ME treatments (P<0.05). Feed cost/weight gain (FC/WG) was significantly decreased in chicks fed with 2,950 kcal/kg ME and 19% CP in starting period (P<0.05). For the growing period, FC/WG was notably increased in ME 3,000, 3,050 kcal/kg treatment than ME 3,100 kcal/kg treatment, and the FC/WG of CP 17, 18% treatment was significantly higher than CP 16% treatment (P<0.05). Thus, the optimum levels of ME and CP to improve the productivity and feed cost for starting, growing and finishing periods were 2,950 kcal/kg ME, 19% CP 3,000 kcal/kg ME, 18% CP and 3,100 kcal/kg ME, 17 or 16% CP, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.145-154
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• 2004

The objective of this experiment was to suggest the optimum cutting height for turf type mixtures{Kentucky bluegrass(Newport) 40％ + tall fescue(Rebell Jr) 20％ + perennial ryegrass (Palmer Ⅱ) 10% + redtop(Barricuda) 10％ + red fescue(Salem) 10% + creeping bentgrass(Crenshaw) IO%}. The fields trials were conducted from 1998 to 2001 at Chungnam National University in order to evaluate the dry matter yield and quality on the cutting heights(3, 4, and 5cm). With increasing the cutting height, the average DM yields of turf type mixtures over 3-year significantly increased, therefore the average total DM yields were obtained 11,158, 12,143 and 13,181㎏/ha at cutting height 3, 4 and 5cm(p<0.05), respectively. The CP content and OMO decreased(p<0.05), whereas the fiber contents slightly increased with increasing the cutting height. The average CPDM and DDM yields were obtained 2,012 and 8,621㎏, 2,097 and 9,461㎏, and 2,298 and 9,951㎏ at cutting height 3, 4, and 5㎝(p<0.05), respectively. The botanical compositions of Kentucky bluegrass and tall fescue were maintained high as 30 ∼ 36％, but that of perennial ryegrass was maintained low as 10-15%. Most of other species were low, but redtop and creeping bentgrass among the other species made up 8∼10％ and 7 ∼ 8% of botanical composition at the last 6th cutting time in 2001, respectively. In general, the level of cutting height of turf type mixtures was not more closely associated with botanical composition. The results of this experiment indicated that a 5㎝ of cutting height of turf type mixtures sown by extensive method would seemed adequate.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.141-147
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• 1989

This experiment was carried out to determine the effects of 13 different application levels of nitrogen(N), phosphorous($P_2O_5$) and potassium($K_2O$) fertilizer at pasture establishment on the winter survival, early spring growth and dry matter(DM) yield, and contents of crude protein(CP) and carbohydrate resewes(CH0-R) of grasses in Suwon from September, 1987 to June, 1988. Winter survival of grasses was high (ca. 90 %) in the plots of N 80 kg, N 120 kg and $K_2O$ application, regardless of $P_2O_5$, while those in zero-N and zero-NPK plots were low as 76 % and 64 %, respectively. Close relationships were observed between winter survival and N & $K_2O$ fertilizer. Early spring growth was vigorous in N-fertilized plots. Heading rate at the first harvest was 50-70 % in all N-plots, regardless of $P_2O_5$ and $K_2O$, while those in zero-N and zero-NPK plots were very low as 20-26 % and 15-18 %,respectively. The DM yield of first harvest was higher in the plots of N 80 kg $ha^{-1}$, regardless of $P_2O_5$ and $K_2O$ levels, and those in zero-N and zero-NPK plots were very low (P < 0.05). The regrowth yleld was not significantly affected by fertilizer levels. The CP content was increased with increasing N level, but CHO-K contents (35-39 %)was not affected by fertilizer levels.Winter survival, early spring growth, DM yield and CP content were significantly influenced by N fertilizer at pasture establishment, regardless of $P_2O_5$ and $K_2O$ application. In this experiment, the compensation effect for spring yield was observed with more N application than usual in next early spring when deficient amount of fertilizer (especially N) was applicated at pasture establishment. Also the optimum application levels of N, $P_2O_5$ and $K_2O$ fertilizer could be recommended as 80, 200 and 70 kg $ha^{-1}$ in new establishing pasture, respectively.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.864-870
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• 2010

This study was conducted to determine the effects of foliage plants on reducing indoor carbon dioxide ($CO_2$). Five foliage plants such as $Hedera$ $helix$ L., $Ficus$ $benjamina$ L., $Pachira$ $aquatica$, $Chamaedorea$ $elegans$, and $Ficus$ $elastica$ were selected and cultivated in two different growth medium (peatmoss and hydroball). Each plant was placed in an airtight chamber and then treated with the combinations of two different $CO_2$ concentrations (500 or 1,000 ppm) and two different light intensities (50 or $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). The change of $CO_2$ concentration (ppm) in the airtight chamber during day and night was measured and then converted into the photosynthetic rate (${\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$). As the results, each foliage plant reduced $CO_2$ level in the airtight chamber for one hour by photosynthesis. $Pachira$ $aquatica$ and $Ficus$ $elastica$ absorbed $CO_2$ more effectively compared to the other plants. The plants exposed to higher $CO_2$ concentration (1,000 ppm) and higher light intensity ($200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) showed more effective $CO_2$ elimination rate and photosynthetic rate. The plants that have wide leaves and big leaf areas such as $Pachira$ $aquatica$, $Hedera$ $helix$ L.,and $Ficus$ $elastica$ showed higher photosynthetic rate than the other plants that have smaller leaves. Released $CO_2$ concentration by respiration of the plants during the night was very low compared to the absorbed $CO_2$ concentration by photosynthesis during the day. There was no significant difference between peatmoss and hydroball medium on reducing $CO_2$ concentration and increasing photosynthetic rate. In conclusion, this study suggested that foliage plants can effectively eliminate indoor $CO_2$. Optimum environmental control in relation to photosyntheis and usage of right indoor foliage plants having lots of leaves and showing active photosynthesis even under low light intensity like indoor light condition would be required to increase the elimination capacity of indoor $CO_2$.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.743-749
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• 2010

Objective of this research was to investigate the effect of various potassium concentrations in fertilizer solution on growth of and nutrient uptake by 'Chugyang' eggplant ($Solanum$ $melongena$ L.). Tissue analyses were conducted to determine the threshold levels of potassium in plants when disorders develop for potassium. The lower leaves of K deficient plants became spotted, yellowing in color, and finally necrosis occurred. The necrosis spread inward and upward. K toxic plants developed necrotic spot at the margin of old leaves and the surface of old leaves were twisted. The tissue K contents in the most recently fully expanded leaves and dry weight of full above ground plant tissue at 35 days after transplanting showed linear and quadratic response to elevated K concentrations with the equation of y=1.127+0.3147x ($R^2$=0.8916) and y=14.92+2.2743x-$0.1402x_2$ ($R^2$=0.8659). When 10% reduction in dry weight set to threshold levels, optimum tissue K contents are in the range from 2.1 to 5.1%. The yield through 150 days after transplanting and tissue K contents at 150 days after transplanting also showed quadratic and linear responses to elevated potassium concentrations in fertigation solution with the equation of y=153.24+345.5x-$18.46x^2$ ($R^2$=0.8620) and y=0.9921+0.3860x ($R^2$=0.9611), respectively. When the 10% reduction in yield is set to threshold levels, the tissue K contents for maximum yield should be around 3.4% to 5.9% in most recently fully expanded leaves.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.666-672
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• 2014

The effect of nitric oxide (NO) treatment on the quality of kiwifruit, cv. Hayward, was studied at room temperature after cold storage for one or three months at $0^{\circ}C$. Kiwifruits cold-stored for one month were treated with $200{\mu}L{\cdot}L^{-1}$ NO and subsequently transferred to room temperature to monitor quality changes over the course of their shelf life. Weight loss was high in fruits not treated with NO. Ethylene production was delayed for two days by NO treatment, and respiration rate was reduced to less half than that of the control. The kiwifruits stored for three months were treated with $N_2$ and 100, 200, or $500{\mu}L{\cdot}L^{-1}$ NO, or air alone. The highest weight loss was observed in kiwifruit treated with $100{\mu}L{\cdot}L^{-1}$ NO. While ethylene production was high in fruits treated with $100{\mu}L{\cdot}L^{-1}$ NO and without the treatment, it was relatively low in the kiwifruit treated with 200 and $500{\mu}L{\cdot}L^{-1}$ NO. Firmness was abruptly decreased in fruits not treated with NO, while the kiwifruit exposed to $200{\mu}L{\cdot}L^{-1}$ NO maintained the s ame level of f irmness for 9 days a t room t emp erature. In addition, growth o f Botrytis cinerea was inhibited by NO as compared with the air and $N_2$ treatments. Our findings indicate that NO can be used effectively for prolonging shelf life and maintaining fruit quality during distribution after cold storage. The optimum NO concentration for cold-stored kiwifruits was found to be $200{\mu}L{\cdot}L^{-1}$.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.57-65
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• 2015

As information technology fusion is accelerated, the researches to improve the quality and productivity of crops inside a plant factory actively progress. Advanced growth environment management technology that can provide thermal environment and air flow suited to the growth of crops and considering the characteristics inside a facility is necessary to maximize productivity inside a plant factory. Currently running plant factories are designed to rely on experience or personal judgment; hence, design and operation technology specific to plant factories are not established, inherently producing problems such as uneven crop production due to the deviation of temperature and air flow and additional increases in energy consumption after prolonged cultivation. The optimization process has to be set up in advance for the arrangement of air flow devices and operation technology using computational fluid dynamics (CFD) during the design stage of a facility for plant factories to resolve the problems. In this study, the optimum arrangement and air flow of air circulation fans were investigated to save energy while minimizing temperature deviation at each point inside a plant factory using CFD. The condition for simulation was categorized into a total of 12 types according to installation location, quantity, and air flow changes in air circulation fans. Also, the variables of boundary conditions for simulation were set in the same level. The analysis results for each case showed that an average temperature of 296.33K matching with a set temperature and average air flow velocity of 0.51m/s suiting plant growth were well-maintained under Case 4 condition wherein two sets of air circulation fans were installed at the upper part of plant cultivation beds. Further, control of air circulation fan set under Case D yielded the most excellent results from Case D-3 conditions wherein air velocity at the outlet was adjusted to 2.9m/s.