• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.80-88
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• 2003

Object The purpose of this study were to evaluate the microtensile bond strength of resin fiber reinforced post to radicular dentin using resin cement according to various dentin surface treatment and to observe the inter face between post and root dentin under SEM Material and Method A total 16 extracted human single rooted teeth were used. A lingual access was made using a #245 carbide bur in a high-speed handpiece with copious air water spray. The post space was mechanically enlarged using H-file(up to #60) and Gates Glidden bures(#3). This was followed by refining of the canal space using the calbrating drill set provided in ER Dentinpost(GEBR, BRASSELER GmbH&Co. KG). The 16 teeth were randomly distributed into 4 group of 4 teeth. Group 1 teeth had their post space prepared using 10% phosphoric acid as root canal surface treatment agent during 20s. The canal was then rinsed with saline and dried with paper point. Group 2 teeth had their post space prepared using 3% NaOCl as root canal surface treatment agent during 30min. The canal was then rinsed with saline and dried with paper point. Group 3 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. The canal was then rinsed with saline and dried with paper point. Group 4 teeth had their post space prepared using 17% EDTA as root canal surface treatment agent during 1min. After rinsing with saline, the canal was rinced 10m1 of 3% NaOCl for 30min. After drying with paper point, the post(ER Dentinpost, GEBR, BRASSELER GmbH&Co. KG) was placed in the treated canals using resin cement. Once the canal was filled with resin cement(Super bond C&B sunmedical co. Ltd.), a lentulo was inserted to the depth of the canal to ensure proper coating of the root canal wall. After 24 hours, acrylic resin blocks($10{\cdot}10{\cdot}50mm$) were made. The resin block was serially sectioned vertically into stick of $1{\cdot}1mm$. Twenty sticks were prepared from each group. After that, tensile bond strengths for each stick was measured with Microtensile Tester. Failure pattern of the specimen at the interface between post and dentin were observed under SEM. Results 1. Tensile bond strengths(meen{\pm}SD$) ) were expressed with ascending order as follows group 4, $12.52{\pm}6.60$ ; group 1, $7.63{\pm}5.83$ ; group 2, $4.13{\pm}2.31$ ; group 3, $3.31{\pm}1.44$. 2. Tensile bond strengths of Group 4 treated with 17% EDTA +3%NaOCl were significant higher than those of group 1, 2 and 3 (p<0.05). 3. Tensile bond strengths of Group 1 treated with 10% phosphoric acid were significant higher than those of group 2 (p<0.05). Tensile bond strengths of Group 4 treated with 17% EDTA +3% NaOCl was significant higher than those of other groups.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.527-534
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• 2008

Effects of dietary concentrate levels based on whole-crop barley silage (BS) on development and meat quality in growing Korean black goats were examined. A total of 36 male goats with similar age and BW were equally allocated to dietary four treatments in a randomized complete block design. Dietary treatments included controls(rice straw ad libitum plus 2.0% concentrate BW－1), and BS ad libitum plus three increasing levels of concentrate BW－1(2.0, 1.5 and 1.0%, respectively), expressed as BS 2.0, BS 1.5 and BS 1.0, respectively. The trial was lasted for 5 months from 14th of May to 12th of October, 2007. At the end of trial, all animals were slaughtered to analyze carcass characteristics and meat quality. Average daily gain was significantly(p<0.05) higher for BS 1.5 and BS 2.0 treatments than for controls. Daily feed intakes for controls(689.3 g) were significantly(p<0.05) higher than those of BS 1.0(585.5 g), but they were significantly(p<0.05) lower than BS 2.0(734.3 g). Carcass and meat percentages were significantly (p<0.05) higher for BS 2.0 and BS 1.5 than for control and BS 1.0 treatments. Shear force and water-holding capacity was greater(p<0.05) for BS 2.0 and BS 1.5 than other treatments. On the basis of feeding whole-crop barley silage to Korean black goats, as dietary concentrate inclusion levels increased, sensory results showed to have a better tendency. In conclusion, it was estimated that the optimal level of dietary concentrates might be 1.5% BW－1, when diets based whole-crop barley silage were fed to growing Korean black goats for their improvements of growth and meat quality.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.73-77
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• 2002

The effect of salicylic acid (SA) on C $d^{2+}$ - induced physiological toxicity in Commelina communis was investigated. 3- weeks old Commelina communis was transferred to and grown in Hoagland solution in the presence or absence of 100 $\mu$M C $d^{2+}$ and SA for 3 weeks. In the treatment of C $d^{2+}$ + SA, the length of stem was increased to 0.7 cm for 3 weeks (C $d^{2+}$, 2.1cm; control, 7.2 cm). C $d^{2+}$ + SA reduced total chlorophyll content up to 86%, and changed chlorophyll a/b ratio below 1.6. C $d^{2+}$ + SA also reduced about 40-78% of water potential, but C $d^{2+}$ increased 16-39% from 1 week to 3 weeks. C $d^{2+}$ + SA also inhibited 27% of Fv/Fm, but in case of C $d^{2+}$, Fv/Fm was not changed. The treatment of C $d^{2+}$ + SA showed about 37-58% inhibition of photosynthetic activity when measured at various light intensity (500-1000 $\mu$mol $m^{-2}$ $s^{-1}$ ). In the case of C $d^{2+}$ treatment, photosynthetic activity was inhibited to 12-15%. Similar effect was found in terms of stomatal conductance. Therefore, it could be concluded that the treatment of C $d^{2+}$ + SA into plant decrease or block various physiological activities and lend to die by double effects of both chemicals.cts of both chemicals..

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.203-210
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• 1999

Of all the nutrients in liquid manure, N has the greatest potential both for the environment and for increasing forage yields. This experiment was carried out to determine the effect of different types and N rates of liquid manure on mineral content and nitrate-N of oats(Avena sativa L.), soil chemical characteristics in Suweon. Seven treatments consisting of chemical fertilizer $120kg\;N\;ha^{-1}$, liquid cattle manure 120, 240 and $360kg\;N\;ha^{-1}$, liquid swine manure 120, 240 and $360kg\;N\;ha^{-1}$ were arranged in a randomized complete block design with three replications. Compared with the plot of chemical fertilizer, increasing liquid manure N rates increased mineral contents of oats. Nitrate-N contents of oats were ranged from 1,881 to $2,605mg\;kg^{-1}$ in all treatments, which was orderly ranked as chemical fertilizer>liquid cattle manure $360kg\;N\;ha^{-1}$> liquid swine manure $240kg\;N\;ha^{-1}$. Contents of exchangeable cation of the soil were appeared to be higher with increasing liquid manure N rates. Amount of total-N and inorganic-N in soil affected by increasing liquid manure N rates, and there was the highest at liquid swine manure $360kg\;N\;ha^{-1}$ among the treatments. Nitrate-N concentration in infiltration water was not remarkably variable during the experimental period. Based on the results of this experiment, it is suggested that the amount of nitrogen in soil was orderly ranked as liquid swine manure $360kg\;N\;ha^{-1}$, followed by liquid swine manure $240kg\;N\;ha^{-1}$.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.259-268
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• 1988

For the purpose of examining the effects of simulated acid rain on nutrient contents of plant tissues in Pintos densiflora seedlings and Forsythia koreana rooted cuttings, the experimental design of randomized block arrangement with three replications was implemented in the experimental field of Yesan National Agricultural Junior College. One-year-old Pinus densiflora seedlings and Forsythia koreana cuttings were planted in the pots filled the mixed soils(nursery soil : forest soil of siliceous sandy loam=1 : 1 v/v) in the early spring of 1986. The regime of artificial acid rain, in terms of spray frequency per month and spray amount at single treatment per plot, was simulated on the basis of climatological data averaged from 30 years records. Simulated acid rain(pH 2.0, pH 4.0, and pH 5.5 as control) containing sulfuric and nutric acid in the ratio of 3 : 2(chemical equivalant basis) diluted with ground water were treated on the experimental plants under condition of cutting off the natural precipitation with vinyl tunnel, during the growing season(May 1 to August 31) in 1986. The results obtained in this study were as follow : (1) As for the nitrogen contents in plant tissues, P. densiflora increased significantly in one-year-old stembranch and root tissues, and F. koreana increased significantly in leaf and root tissues, as the pH levels of acid rain decreased. (2) The available phosphate contents in root tissues of P. densiflora, and in leaf and root tissues of F. koreana were significantly decreased, as the pH levels of acid rain decreased. (3) $K_2O$, CaO and MgO contents in plant tissues were significantly decreased in the both species as the pH levels decreased. And the effects of acid rain on F. koreana were higher than those of P. densiflora. (4) Sulfur contents of plant tissues in the both species were increased at pH 2.0 treatment. There were significant differences among three acid rain treatments in leaf and root tissues of P. densiflora, and in all parts of F. koreana. (5) In the effects of simulated acid rain on the both species and the tested soils, in general, F. koreana revealed higher sensitiveness than P. densiflora, and the lower pH levels of simulated acid rain were treated, the more sharp reaction was showed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.4
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• pp.304-312
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• 2013

This study was conducted to investigate the effect of total neutral detergent fiber (NDF) and forage-derived NDF (fNDF) on nutrient intake and milk production in Holstein dairy cows. Thirty-six Holstein dairy cows at weeks 4 to 20 of lactation were included in this study. The cows were arranged in a randomized complete block design and assigned to one of six diets: 1) 38% NDF with 18% fNDF (HN-HF); 2) 38% NDF with 15% fNDF (HN-MF); 3) 38% with 12% fNDF (HN-LF); 4) 34% NDF with 18% fNDF (LN-HF); 5) 34% NDF with 15% fNDF (LN-MF); and 6) 34% with 12% fNDF (LN-LF). The cows were fed a total mixed ration twice daily (07:00 and 18:00 h) and given ad libitum access to feed and water throughout the experiment. Data on the intake of nutrients (DM, NEl, CP, NDF, fNDF, NFC), milk yield, composition, fat-corrected milk (FCM), fat and protein corrected milk (FPCM), and energy corrected milk (ECM) were analyzed. Lower dietary concentrations of total NDF or fNDF resulted in an increase in DM, NEl, and NFC intake (p<0.01), milk yield (p<0.05) and a lower milk fat concentration (p<0.01). The LN treatment showed no significant differences in milk fat concentration compared to the HN however, further reduction in fNDF decreased milk fat content (p<0.01). The lowest level of milk fat was observed in the LN-LF diet group. Changes in the dietary concentrations of NDF or fNDF did not affect the concentrations of milk protein or SNF (solid not fat), although the yield of milk protein and SNF increased with higher milk yield (p<0.01). The level of fNDF influenced the level of FCM (p=0.07), as well as FPCM and ECM yield (p<0.05). A highly positive correlation between fNDF intake and milk fat concentration was observed in animals with low NDF compared to those offered high NDF. A strong correlation was also observed between milk yield and low NDF intake compared to high NDF intake.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.114-159
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• 2012

The Northern Song Dynasty Period (北宋時代) was a drastic transitional era in all aspect of Chinese society including the politico-economic system, ideology and cultural trait. These changes that began in the late Tang (唐) Dynasty Period accomplished in the Northern Song Dynasty. In this phase, the fundamental change influenced in all institutional area; and among them, the capital city planning and its associating building technology to pile stone walls shows one of the significant change of those time. Based on the geographical factor, confluences of many rivers, the Kaifeing (開封) area where the BianLieng palace had developed as a political and economical centre since the Tang Dynasty when the Grand Canal was constructed. According to archaeological researches, the central city structure of Dongjing Walled Town was begun to plan in the late Tang Dynasty and formed in Five Dynasties. The fundamental functional change of city completed in the Midnorthern Song Dynasty. In spite of the relatively late beginning of archaeological investigations to Kaifeng Walled Town and Dongjing Walled Town due to unfavourable natural environment, excavations inaugurated since 1981 have achieved the significant investigations including the actual measurement and excavation to the outer wall, the preliminary excavation to the inner city area, the investigation and excavation to the royal palace of Song and the survey to the royal palace of King Zho in the Ming (明) Dynasty. These surveys have provide important data to reconstruct the 변량 palace, and elucidate the characteristics of city plan in the Dongjing Walled Town and the institutional change of capital city plan of the Northern Song Dynasty. The basic layout of Dongjing Walled Town reflect the realisation of ideality of the late Chinese medieval capital city structure that establish the commercial and economic centre based on the intensification of emperor's power by means of the organisation of ethical institution and the development of commercial economy. Firstly, the central place of the Kaifeng area is encircled with triple walls. This emphasise the authority of emperor located on the summit in the hierarchical ethic system succeeding to the main capital city plan of the late phase of ancient China. Secondly, the location of Dongjing Walled Town was decided by the transport network and the commercial function and defence function. Thirdly, this site shows the change of city structure and landscape of the Northern Song Dynasty. The closed Fengri (坊里: block) system transferred the open Jiexiang (街巷: road) system. Fourthly, the capital city was characterised by the free market trade and the diversification of market place. Fifthly, a convenient transport network in the Bian River, a centre of the Grand Canals, enabled to construct the Kaifeng Walled Town. Therefore, the Northern Song Dynasty continuously accomplished the developed water system as concerning about the utilisation of waterways after the construction of city.

• Journal of agriculture & life science
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• v.53 no.4
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• pp.19-28
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• 2019

This study was conducted to investigate the effect of nutrient solution strength and duration of nutrient starvation on the growth and development of strawberry (Fragaria x ananassa Duch.) 'Maehyang' and 'Sulhyang' at the flowering stage. Cuttings of runner plants were stuck on November 23th, 2017 and were covered with a layer of black plastic film to block light from penetrating and keep the relative humidity high. The black plastic film was removed after 16 days and rooted plants were cultivated for one month with irrigation of water. The Yamazaki nutrient solution with an electrical conductivity (EC) of 1.85 or 3.71 dS·m-1 (1x or 2x ionic strength, respectively) and pH 5.55 was fed to plants after either 0 (control), 1, 3 or 5 weeks of nutrient starvation to the end of experiment. Plant height in both cultivars decreased gradually with the increase in duration of nutritional starvation. The earlier the nutritional starvation started, the smaller the shoot fresh weight of 'Maehyang'. Hence the greatest shoot fresh weight was obtained in the control which was supplied with the nutrient solution continuously. Shoot fresh weight of 'Sulhyang' was the greatest in 1x ionic strength and one week of nutrient starvation before planting. Although number of flowers on the first flower cluster of 'Maehyang' and 'Sulhyang' showed no significant differences, 'Maehyang' had the greatest number of flowers in the 2x ionic strength solution and one week of nutrient starvation before planting, while 'Sulhyang' had that in the 1x ionic strength treatment. These results suggest that it is considered effective to supply a nutrient solution at a low concentration for a short period of time for increasing the number of flower differentiated on the first flower cluster in both cultivars.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.441-447
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• 2023

Lead(Pb), which is currently mainly used for shielding purposes in the medical radiation, has excellent radiation shielding functions, but is continuously exposed to radiation directly or indirectly due to the harmfulness of lead itself to the human body and the inconvenience caused by its heavy weight. Research on shielding materials that are human-friendly, lightweight, and convenient to use that can block risks and replace lead is continuously being conducted. In this study, based on the commonly used polyethylene terephthalate (PET) film and the fabric material used in actual radiation protective clothing, a multi-layer thin film was realized through sputtering and vacuum deposition of bismuth, tungsten, and tin, which are metal materials that can shield radiation. Thus, a shielding film was produced and its applicability as a radiation shielding material was evaluated. The radiation shielding film was manufactured by establishing the optimized conditions for each shielding material while controlling the applied voltage, roll driving speed, and gas supply amount to manufacture the shielding film. The adhesion between the parent material and the shielding metal thin film was confirmed by Cross-cut 100/100, and the stability of the thin film was confirmed through a hot water test for 1 hour to measure the change of the thin film over time. The shielding performance of the finally realized shielding film was measured by the Korea association for radiation application (KARA), and the test conditions (inverse wide beam, tube voltage 50 kV, half layer 1.828 mmAl) were set to obtain an attenuation ratio of 16.4 (initial value 0.300 mGy/s, measured value 0.018 mGy/s) and damping ratio 4.31 (initial value 0.300 mGy/s, measured value 0.069 mGy/s) were obtained. by securing process efficiency for future commercialization, light and shielding films and fabrics were used to lay the foundation for the application of films to radiation protective clothing or construction materials with shielding functions.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.171-185
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• 2023

This study was conducted to investigate the effects of supplementation of Allium hookeri (AH) root powder on the gut microbiome, immunity, and health in broiler chickens fed experimental diets from d 10 to 28. A total of 60 10-day-old Ross 308 broilers were weighed and assigned to two dietary treatments with 5 birds per cage in a randomized complete block design based on body weight. The two experimental diets consisted of a control diet based on corn-soybean meal and the control diet supplemented with 0.3% AH root powder. All birds were fed ad libitum with experimental diets and water for 18 d. At 28 d, two birds near the median weight from each cage were selected for cecal content and small intestinal tissue sample collection. The addition of AH changed the gut microbiome by increasing probiotic candidate beneficial bacteria such as Enterococcaceae, Lactobacillaceae, Limosilactobacillus, Cuneatibacter, and Ruminoccoides. Regarding gut immunity, the supplementation of AH resulted in changes in intestinal immune cells, including reduced CD3+CD4+ T cells, which are a type of helper T cell, in the small intestine of birds (P=0.049). Additionally, there was a tendency to increase the expression of antioxidant function-related gene such as GPX2 (P=0.060), but no significant changes were observed in cytokines such as IL1b, IL6, and IL10. Overall, the addition of AH root powder may have positive effects on the microbiome of the chickens. This may help promote gut health in broiler chickens at the age of d 10 to 28.