• Advances in materials Research
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• 제4권1호
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• pp.13-22
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• 2015

Concrete suffers strength loss when subjected to elevated temperatures during an accidental event such as fire. The loss in strength of concrete is mainly attributed to decomposition of C-S-H gel and release of chemically bound water, which begins when the temperature exceeds $500^{\circ}C$. But it is unclear about how much strength loss occurs in different stages of heating, retention and cooling regimes. This work is carried out to separate the total strength loss into losses during different stages of heating, retention and cooling. Tests were carried out on both Ordinary Portland Cement (OPC) based concrete and Ground Granulated Blast Furnace Slag (GGBFS) blended concrete for $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$ and $800^{\circ}C$ with a retention period of 1 hour for each of these temperature levels. Furnace cooling was adopted throughout the experiment. This study reports strength loss contribution during heating, retention and cooling regimes for both OPC based and GGBFS based concretes.

• Bulletin of the Korean Chemical Society
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• 제20권10호
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• pp.1159-1164
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• 1999

The study investigated the effect of carrier composition (ionic strength and pH) on the retention of various proteins in flow field-flow fractionation (Flow FFF) as well as the conformational change of Bovine Serum Albumin (BSA) with urea concentration, storage time and temperature. The study found that the retention of protein in Flow FFF increased with the ionic strength of the carrier liquid. Most proteins were well solubilized at pH = 7-8. The hydrodynamic diameters obtained from Flow FFF retention data agree well with theoretical values. The retention increased and the peak shape became distorted at extreme pH conditions of the carrier solution. The selected carrier composition for comparison between the literature value of proteins was 0.05 M tris buffer solution with a pH of 8. Storing BSA at 4 ±2℃ over a period of three months resulted in slow dimerization. Also, in case of the storage of BSA at 37 ±5℃ for one week, the retention of both BSA monomer and dimer increased with the urea concentration. Finally, the structural composition of specific enzymes: malonyl-CoA decarboxylase (MCDC) and malonyl-CoA synthesis (MCS) was determined by using Flow FFF at specific carrier solutions. The molecular weight of the natural MCDC was determined to be 208 kDa, which means it is a homotetramer, while that of the MCS was determined to be 47 kDa, which means it is a monomer.

• 한국가금학회지
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• 제40권2호
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• pp.129-138
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• 2013

An experiment was conducted to determine the effects of origins of soybean meal (SBM) on growth performance, nutrients and energy retention and fecal microflora in broilers. The SBM originating from Korea, Brazil and India were used. A total of 480 broiler chicks (average initial BW, 41.8 g) were randomly allotted to 6 treatments. Each treatment had 4 replicate pens with 20 chicks per pen. Birds were fed diets containing SBM originated from Korea (domestic SBM), Brazil or India (imported SBM) and the diets were based on the total amino acid (TAA) or true digestible amino acid (TDAA). Experimental diets were fed in two phases, starter (d 0~21) and finisher (d 22~35). The overall weight gain, feed intake and FCR were better (P<0.05) in birds fed Korean SBM. During starter and finisher periods, birds fed diets containing Korean SBM had greater (P<0.05) retention of GE, DM, and CP (P<0.05) as compared with Birds fed diets containing SBM from India. In addition, diets formulated on TDAA basis had grater (P<0.05) CP retention during starter period and DM, GE and CP retention during finisher period. There were no differences (P>0.05) in the excreta microflora and overall feed cost per kg body weight gain in birds fed SBM from different origins; however, diets formulated on TDAA basis had lesser (P<0.05) feed cost per kg body weight gain in birds when compared with diets formulated on TAA basis. These results indicate that Korean SBM has better nutrients digestibility than SMB originated from Brazil and India, which contributes to the improved performance of broilers. In addition, better performance was obtained when diets were formulated on TIDAA basis.

• 한국식품영양과학회지
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• 제23권1호
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• pp.143-149
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• 1994

Carotenoids isolated from orange peels were determined physicocohemical properties with TLC, UV-spectrophotometer and HPLC etc., and the results were as follows . Maximum absorption wavelength of the isolated carotenoids was 415nm when the result was similar to $\beta$-carotene as 423nm. Eight spots were obtianed from TLC, and identified lutein, lycopene, $\alpha$-carotene and $\beta$-carotene with HPLC. The effect pH during the storage period of isolate carotenoids, the period when the amount of pigment retention was over 50% in pH 5, 6 and 7 , after 10 days . The amount of pigment retention was lower in control than in treatment of sugars such as fructose, glucose and sorbitol , but sucrose was similar to the control, Isolated carotenoids were stable to ascorbic acid, and the amount of pigment retention was over 70% after 10 days. The amount of pigment retention in the effect oforganic acid was higher in treated citric acid , lactic acid and tartaric acid than in control, but lower in treated maleic acid and succinic acid. Isolated carotenoids were stable at 50 $^{\circ}C$, and the amount of pigment retention was over 50% at 10$0^{\circ}C$.

• 한국환경농학회지
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• 제22권4호
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• pp.251-254
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• 2003

Phosphorous removal rate and emergent plant growth were examined of a surface-flow constructed treatment wetland system, whose dimensions were 31 meter in length and 12 meter in width. The system was established on floodplain in the down reach of the Kwangju Stream in Korea in one and half months from May to June 2001. Cattails(Typha angustiflora) were transplanted in the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream were funneled into it via a pipe by gravity flow and its effluent were discharged back into it. The stems of cattails grew from 45.2 cm in July 2001 up to 186 cm in September 2001 and the number of cattail stems per square meter increased from 22 in July 2001 to 53 in September 2001. The early establishment of cattails was good. Volume and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Inflow averaged $40\;m^3/day$ and hydraulic retention time was about 1.5 days. The concentration of total phosphorous in influent and effluent was 0.85 mg/L, 0.41 mg/L, respectively. The average removal rate of total phosphorous in the system was about 52%. The retention efficiency was slightly lower, compared with that in surface-flow wetlands operating in North America, whose retention efficiency was reported to be about 57%. The lower abatement rate could result from the initial stage of the system and inclusion of two cold months into the six-month monitoring period. Root rhizosphere in wetland soils and litter-soil layers on bottoms were not properly developed. Increase of standing density of cattails within a few years will establish both root zones and substrates beneficial to the removal of phosphorous, which may lead to increase of the phosphorous retention rate. The system was submerged one time by heavy storm during the monitoring period. The inundation, however, scarcely disturb its environment.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 1997년도 추계학술대회
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• pp.47-47
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• 1997

• 대한치과교정학회지
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• 제53권6호
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• pp.365-373
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• 2023

Objective: To investigate the potential correlation between fixed orthodontic retention failure and several patient- and treatment-related factors. Methods: Patients finishing treatment with fixed appliances between 2016 and 2017 were retrospectively included in this study. Those not showing fixed retention failure were considered as control group. Patients with fixed retention failure were considered as the experimental group. Additionally, patients with failure of fixed retainers in the period of June 2019 to March 2021 were prospectively identified and included in the experimental group. The location of the first retention failure, sex, pretreatment dental occlusion, facial characteristics, posttreatment dental occlusion, treatment approach and presence of oral habits were compared between groups before and after treatment separately by using a Fisher exact test and a Mann-Whitney U test. Results: 206 patients with fixed retention failure were included, 169 in the mandibular and 74 in the maxillary jaws. Significant correlations were observed between retention failure in the mandibular jaws and mandibular arch length discrepancy (P = 0.010), post-treatment growth pattern (P = 0.041), nail biting (P < 0.001) and abnormal tongue function (P = 0.002). Retention failure in the maxillary jaws was more frequent in patients with IPR in the mandibular jaws (P = 0.005) and abnormal tongue function (P = 0.021). Conclusions: This study suggests a correlation between fixed retention failure and parafunctional habits, such as nail biting and abnormal tongue function. Prospective studies with larger study populations could further confirm these results.

• 대한치과교정학회지
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• 제38권1호
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• pp.31-40
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• 2008

최근 절대적인 고정원의 등장으로 다른 부작용 없이 구치부 압하 치료를 가능하게 하였고, 비수술적으로 개방교 합의 심미적인 치료를 가능하게 하였다. 그러나, 이러한 치료법의 장기적인 안정성에 대한 연구는 많이 부족한 실정이다. 이에 본 연구에서는 miniscrew implant 를 이용하여 상악 구치를 압하시켜 치료한 성인 개방교합 환자 11명(남자 1명, 여자 10명) 을 대상으로 치료 전후, 그리고 유지기의 골격성, 치아 치조성 변화를 측모 두부 방사선사진을 이용하여 평가하였으며 계측치의 치료 전후 변화량간의 상관관계와 치료에 의한 변화량과 재발량과의 상관관계를 규명하여 상악구치의 압하를 통해서 개방교합을 치료할 때에 안정성을 평가하였다. 그 결과로 상악 구치는 2.22 mm 압하 (p < 0.001) 가 일어났고, 평균 17.4 개월 유지 후 0.23 mm 의 정출 (p = 0.359) 이 나타났으며, 재발율은 10.36%로 나타났다. 전치부의 수직피개는 평균 5.47 mm 의 증가 (p < 0.01) 가 나타났고 평균 17.4 개월 유지 후 0.99 mm의 감소 (p < 0.05) 가 나타나서, 재발량은 18.10%로 계산되었다. 치료 전후 수치 변화량의 상관분석을 통해 상악 구치 압하량과 하악 평면각 변화량이 상관관계 (p < 0.05) 가 있었다. 치료 전의 개방교합량, 하악 평면각, 전하안면고 경과 치료 후의 수직피개 재발량과는 상관관계가 없었다. 상악 구치 압하량과 수직피개 개선량에서 치료에 의한 변화량과 재발량이 통계적으로 유의한 상관관계를 보였고, 이를 토대로 재발량을 예측할 수 있었다. 이상의 결과를 통하여 성인 개방교합 환자에서 miniscrew implant를 이용한 상악구치부의 압하는 비수술, 심미적 접근방법으로 효율적이고 안정적인 치료방법으로 유용하게 사용할 수 있을 것으로 생각된다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.243-249
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• 2001

Thirty six barrows with an initial body weight of 28 kg were used to determine the effect of two dietary Se sources and a wide range of Se levels encompassing 0.3, 1.0, 3.0, 5.0, 7.0, and 10.0 mg/kg Se. The organic Se form was a Se-enriched yeast product, whereas the inorganic Se source was sodium selenite. The experiment was a $2{\times}6$ RCB design conducted in three replicates. Each barrow was placed in an individual metabolism crate and provided their dietary treatment and water on an ad libitum basis for a minimum 2 wk period, whereupon feed intake was adjusted to a constant intake within replicate at approximately 90% of intake for a 4 d adjustment period. Urine and feces were subsequently collected for a 7 d period and analyzed for Se and minerals. The results demonstrated that urinary Se was approximately 25% higher when pigs were fed sodium selenite (p<0.01), whereas fecal Se was lower by 25% (p<0.01). Se retention tended to be higher when organic Se was provided (p>0.15). Urinary Se increased as dietary Se level increased for both Se sources but increased more and at a high rate when sodium selenite was fed resulting in an interaction response (p<0.01). Fecal Se increased linearly as the dietary level of both Se sources increased, but the fecal Se from organic Se increased at a faster rate resulting in an interaction response (p<0.01). Se retention increased linearly (p<0.01) as dietary Se increased for both Se sources. The apparent digestibility of Se increased by Se level when pigs were fed sodium selenite, but not when the organic Se source was provided resulting in an interaction response (p<0.05). Retention of consumed Ca, Zn increased when pigs were fed organic Se (p<0.05) whereas P and Na retention were higher when the inorganic Se was provided. Mineral retention was not affected by dietary Se level except P. These results suggest that Se excretion by urine was the main route of excretion when pigs were fed sodium selenite but the fecal route when Se-enriched yeast was provided. The excretion of Fe, Zn, Mn, and Cu via urine and feces was not affected by high dietary Se level or dietary Se sources.

• Asian-Australasian Journal of Animal Sciences
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• 제10권1호
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• pp.15-19
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• 1997

An experiment was conducted to clarify the effects of dietary supplementation of monensin or salinomycin on mineral utilization of growing goats. Six goats weighing 10.54 kg initially were randomly assigned to treatments in a replicated $3{\times}3$ Latin square design. Treatments were a basal diet, basal plus 30 ppm monensin and basal plus 20 ppm salinomycin on a DM basis. The basal diet was a mixture of Italian ryegrass wafer, soybean meal, ground maize and $CaCO_3$ with DM proportions of 50, 13.76, 36 and 0.24%, respectively. Each period lasted for 21 days, and the apparent absorption and retention of minerals were measured during the last 7 days of each period. Salinomycin supplementation improved NDF digestibility and plasma glucose. The apparent absorption and retention of Ca, P, Mg, Na and K were not influenced by the treatments. The concentrations of plasma Ca, P, Mg, Na, K and Cl were similar in all treatments. The ionophore supplementation had no significant effect on acid excretion. The results suggest that 30 ppm monensin or 20 ppm salinomycin supplementation is not effective in improving the utilization of Ca, P, Mg, Na and K in growing goats fed a diet composed of the 50% concentrate.