• Radiation Oncology Journal
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• v.7 no.1
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• pp.15-22
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• 1989

Investigations were carried out into the time-and dose-related changes in acute skin reaction following graded single dose (20,30 and 40 Gy) of x-ray irradiation in Wistar rats, in order to evaluate the radioprotective effect of Diethon on skin. For the duration of skin response over 1. 5 score in dose of 40 Gy, the Diethone group of 24.7 days was significantly different (p<0.02) from that of control (29.8 days) and vaseline (29.2 days) groups, it was $17.1\%$ diminution of skin response period compared with that of control group. By the averaging daily scores for 10 days during peak skin reaction the mean scores were obtained. Mean score of Diethone group $(2.43\pm0.22)$ was significantly different (p<0.01) from that of control $(2.91\pm0.23)$ and vaseline $(2.81\pm0.18)$ groups of 40Gy dose. By iso-effect dose obtained at level of 2.5 score the dose reduction factor (DRF) was 1.41 which reduced radiation dose of $41\%$ by radioprotective effect of Diethone. From this experimental data, it may be possible to give higer radiation dose to large and/or radioresistant tumor mass rather than conventional treatment doses for improving therapeutic ratio by using topical application of skin radioprotector.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.721-729
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• 2008

The purpose of this study is to investigate the engineering properties of concrete for the early strength development. As a result of reviewing it by establishing each experimental factor and level, the cement had more excellent quality performance in CHC and HESPC than OPC. This study has shown that the PC series admixture was more excellent in side of elapsed time (aging) and early strength development than PNS series admixture. In addition, there was much difference according to the curing temperature, but the early strength development showed the considerable vulnerability in curing temperature below $12^{\circ}C$. To satisfy the strength requirements of 5 MPa/18 hr this study has shown that it needed the curing temperature over $17^{\circ}C$ to the minimum in OPC, over $14^{\circ}C$ in CHC, and over $11^{\circ}C$ in HESPC. On the other hand, as to the strength properties according to W/C, the less W/C was, the more strength development was excellent. If this study is to be used in construction filed on a basis of this result, this researcher is considered as possible of the economic execution of construction by advancing the early strength and by the reduction of construction cost according to shortening construction duration.

• Journal of Environmental Policy
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• v.10 no.1
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• pp.129-150
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• 2011

This paper proposes an improvement to differentiate assessment procedure for projects in consideration of their environmental impact as a means to improve efficiency in environmental impact assessment ("EIA") procedure. The targets of analysis were limited to lower impact projects. The current EA system in Korea has already attempted to introduce separate proceedings for certain projects.Tangible results from these efforts, however, have been limited. Other countries have adopted a "screening" system to determine whether EIA is applicable to a particular project, and if so, what procedure will be used therein. Therefore, this study suggests the screening as the process wherein need for EIA is determined with respect to projects which have undergone Prior Environmental Review System(PERS) and which appear to have comparatively negligible environmental impact. In this case, EIA can be omitted and the developer can then draft a mitigation plan instead. This study found that exempting certain projects deemed as having low environmental impact can considerably shorten the duration required for both environmental assessment and consultation, thereby improving efficiency. Other expected effects from the adoption of this screening include reduction in delays in project execution due to environmental assessments and reduced red tape through the provision of increased autonomy to developers and the approving authorities.

• Journal of the Korean Geographical Society
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• v.43 no.1
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• pp.1-19
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• 2008

This study intends to clarify the characteristics and causes of current changes in wintertime precipitation in Korea and to predict the future directions based on surface observational $(1973/04\sim2006/07)$ and modeled (GFDL 2.1) climate data. Analyses of surface observation data demonstrate that without changes in the total amount of precipitation, snowfall in winter (November-April) has reduced by 4.3cm/decade over the $1973\sim2007$ period. Moreover, the frequency and intensity of snowfall have decreased; the duration of snow season has shortened; and the snow-to-rain day ratio (STDR) has decreased. These patterns indicate that the type of wintertime precipitation has changed from snow to rain in recent decades. The snow-to-rain change in winter is associated with the increases of air temperature (AT) over South Korea. Analyses of synoptic charts reveal that the warming pattern is associated with the formation of a positive pressure anomaly core over northeast Asia by a hemispheric positive winter Arctic Oscillation (AO) mode. Moreover, the differentiated warming of AT versus sea surface temperature (SST) under the high pressure anomaly core reduces the air-sea temperature gradient, and subsequently it increases the atmospheric stability above oceans, which is associated with less formation of snow cloud. Comparisons of modeled data between torrent $(1981\sim2000)$ and future $(2081\sim2100)$ periods suggest that the intensified warming with larger anthropogenic greenhouse gas emission in the $21^{st}$ century will amplify the magnitude of these changes. More reduction of snow impossible days as well as more abbreviation of snow seasons is predicted in the $21^{st}$ century.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.3
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• pp.177-197
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• 2011

In this study, a series of fire experiments under $HC_{inc}$ and ISO834 (duration of 4 hour) fire scenarios were carried out for three different types of fire protection measures for the segment joint to evaluate their applicabilities to an immersed tunnel. The experimental results revealed that an expansion joint installed to allow relative movements between concrete element ends in an segment joint is the most vulnerable to a severe fire. For the fire protection measure where the originally designed steel plates at an expansion joint arc replaced by fire-resistant boards, the experiments showed that they cannot achieve good fireproofing performance under both $HC_{inc}$ fire scenario and ISO834 (4 hour) fire scenarios since the installation of fire-resistant boards results in the reduction of the sprayed fire insulation thickness. On the other hand, the application of modified bent steel plates replacing the original steel plates was proved to be very successful in fireproofing of the expansion joint due to more sprayed materials filled in bent steel plate than in the original design concept as well as higher adhesion between the steel plate and the sprayed fire insulation layer.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1702-1710
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• 2017

Objective: The study examined the effect of condensed tannins (CT) containing Ficus infectoria and Psidium guajava leaf meal mixture (LMM) supplementation on nutrient metabolism, methane emission and performance of lambs. Methods: Twenty four lambs of ~6 months age (average body weight $10.1{\pm}0.60kg$) were randomly divided into 4 dietary treatments (CT-0, CT-1, CT-1.5, and CT-2 containing 0, 1.0, 1.5, and 2.0 percent CT through LMM, respectively) consisting of 6 lambs each in a completely randomized design. All the lambs were offered a basal diet of wheat straw ad libitum, oat hay (100 g/d) along with required amount of concentrate mixture to meet their nutrient requirements for a period of 6 months. After 3 months of experimental feeding, a metabolism trial of 6 days duration was conducted on all 24 lambs to determine nutrient digestibility and nitrogen balance. Urinary excretion of purine derivatives and microbial protein synthesis were determined using high performance liquid chromatography. Respiration chamber study was started at the mid of 5th month of experimental feeding trial. Whole energy balance trials were conducted on individual lamb one after the other, in an open circuit respiration calorimeter. Results: Intake of dry matter and organic matter (g/d) was significantly (p<0.05) higher in CT-1.5 than control. Digestibility of various nutrients did not differ irrespective of treatments. Nitrogen retention and microbial nitrogen synthesis (g/d) was significantly (p<0.01) higher in CT-1.5 and CT-2 groups relative to CT-0.Total body weight gain (kg) and average daily gain (g) were significantly (linear, p<0.01) higher in CT-1.5 followed by CT-1 and CT-0, respectively. Feed conversion ratio (FCR) by lambs was significantly (linear, p<0.01) better in CT-1.5 followed by CT-2 and CT-0, respectively. Total wool yield (g; g/d) was linearly (p<0.05) higher for CT-1.5 than CT-0. Methane emission was linearly decreased (p<0.05) in CT groups and reduction was highest (p<0.01) in CT-2 followed by CT-1.5 and CT-1. Methane energy (kcal/d) was linearly decreased (p<0.05) in CT groups. Conclusion: The CT supplementation at 1% to 2% of the diet through Ficus infectoria and Psidium guajava LMM significantly improved nitrogen metabolism, growth performance, wool yield, FCR and reduced methane emission by lambs.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.71-76
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• 2011

In this study, a heavy metal stabilization treatment using waste resource stabilizing agents was utilized on army firing range soil contaminated with Pb and Cu. Both calcined oyster shells (COS; 5% w/w) and waste cow bone (WCB; 3% w/w) were applied for a wet-curing duration of 28 days. Following the stabilization treatment, the process efficiency was evaluated by various extraction methods for Pb and Cu. Neutral and weak acid extraction methods, such as water soluble extraction and SPLP, did not show positive results for heavy metal stabilization with very low leachability. On the other hand, TCLP and 0.1 N HCl extraction showed that the stabilizing agents significantly reduced the amount of the heavy metals leached from the soil, which strongly supports that the treatment efficiency is positively evaluated in acidic leaching conditions. Specifically, in the 0.1 N HCl extraction, the reduction efficiencies of Pb and Cu leaching were 99.9% and 83.9%, respectively. From the sequential extraction results, a difference between Pb and Cu stabilization was observed, which supports that Pb stabilization is more effective due to the formation of insoluble Pb complexes. This study demonstrates that the application of waste resources for the stabilization of heavy metals is feasible.

• Parasites, Hosts and Diseases
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• v.36 no.2
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• pp.127-132
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• 1998

Immunotherapy has been used in support of trimethoprim-sulfamethoxazole treatment for Pneumocvstis corinii pneumonia. The present study investigated the therapeutic or preventive effects of heterogeneous hyperimmune IgG antibody (HIA) in experimental rats. Their immunity was suppressed by steroid injection, and they were also injected peritoneally with HIA which reacted with 40-55, 92, 116, and 200 kDa bands of the crude antigen. All rats were infected by p. ccrinii and the cystic forms on lung impression smears were counted. The count was 20.5-76.5 (mean 52.5 ± 19.)1 in those which received steroid only, but decreased to 6.0-21.0 (mean 13.5 : 10.6) in those of group 3 which received HIA for the same duration. In other groups, the mean count ranged from 29.9 t 32.9 to 54.1 t 47.7, and in those which received 13.7 mg HIA the reduction effect was greater than in those which received 6.8 mg or 20.5 mg HIA. The present finding confirmed that in rats during the early stage of infection, the heterogeneous HIA to MSG antigen bands had a partial effect on p. cori,nii pneumonia, both prophylactically and therapeutically.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.720-726
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• 1999

High voltage pulsed electric fields (PEF) technology is a non-thermal technique which is applicable to extract useful components froms biological materials. This research suggested the possibility for extracting carotenoid pigments from Phaffia rhodozyma by PEF treatments. The yeast cell suspensions were treated with high voltage pulses in a recycled PEF treatment chamber which consists a pair of thin plates of stainless steel adhering to a small chamber with approximately $1{\sim}4\;mm$ gap. A 2.5 log reduction in survivability and more than 98% of electropermeabilization of the yeast cells could be achieved by PEF treatment for $300\;{\mu}s$ with an electric field of 30 kV/cm and pulse duration of $1\;{\mu}s$. When the yeast cell suspended in 0.01% NaCl solution were treated with PEF under various conditions, carotenoid pigments were not extracted. However, the PEF treatment of the yeast cell suspensions in 0.01% $CaCl_2$ solution, have positive effects on the extraction of carotenoid pigments ($27.3\;{\mu}g/g$ of dried yeast).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.17-26
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• 1979

Comparative tolerance of the new rice varieties from Indicax Japonica cross to elastic and plastic chilling injuries was examined at the 3rd leaf-stage, the most sensitive stage to chilling during nursery, using a chilling chamber set 11\circ C, 13hrs. 20K lux day/5$^{\circ}C$ night. Seedlings were reared until 35 days after seeding in a 26\circ C, 13hrs. day / 18\circ C night chamber except the period of chilling treatment for 0, 3, 4, 6, 8 or 10 days. The new varieties were approximately twice susceptible to elastic injuries, and thrice susceptible to plastic injuries than the Japonica varieties in the term of chilling duration. Among the variables indicating apparant chilling injuries the reduction in dry matter responded most sensitively and differentiated well the varietal difference in chilling resistance even with shorter chilling period. Sequential aspects of the cause and effect relations involved in the development of the apparant chilling injuries are discussed and a schematic diagram is presented as Fig. 5 in the text.