• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1145-1151
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• 2016

This study was conducted to evaluate the relative bioavailability (RBV) of 25-hydroxycholecalciferol (25-OH-$D_3$) to cholecalciferol (vitamin $D_3$) in 1- to 21-d-old broiler chickens fed with calcium (Ca)- and phosphorus (P)-deficient diets. On the day of hatch, 450 female Ross 308 broiler chickens were assigned to nine treatments, with five replicates of ten birds each. The basal diet contained 0.50% Ca and 0.25% non-phytate phosphorus (NPP) and was not supplemented with vitamin D. Vitamin $D_3$ was fed at 0, 2.5, 5.0, 10.0, and $20.0{\mu}g/kg$, and 25-OH-$D_3$ was fed at 1.25, 2.5, 5.0, and $10.0{\mu}g/kg$. The RBV of 25-OH-$D_3$ was determined using vitamin $D_3$ as the standard source by the slope ratio method. Vitamin $D_3$ and 25-OH-$D_3$ intake was used as the independent variable for regression analysis. The linear relationships between the level of vitamin $D_3$ or 25-OH-$D_3$ and body weight gain (BWG) and the weight, length, ash weight, and the percentage of ash, Ca, and P in femur, tibia, and metatarsus of broiler chickens were observed. Using BWG as the criterion, the RBV value of 25-OH-$D_3$ to vitamin $D_3$ was 1.85. Using the mineralization of the femur, tibia, and metatarsus as criteria, the RBV of 25-OH-$D_3$ to vitamin $D_3$ ranged from 1.82 to 2.45, 1.86 to 2.52, and 1.65 to 2.05, respectively. These data indicate that 25-OH-$D_3$ is approximately 2.03 times as active as vitamin $D_3$ in promoting growth performance and bone mineralization in broiler chicken diets.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제32권5A호
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• pp.317-325
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• 2012

In this study, to evaluate the shrinkage behavior of ultra high performance fiber reinforced concrete (UHPFRC) under restrained condition, restrained shrinkage test was performed according to ring-test mostly used at home and abroad. Ring-test was performed with the various thicknesses and radii of inner steel ring to give different degree of restraint. Free shrinkage and tensile tests were carried out simultaneously to estimate the degree of restraint, stress relaxation, and shrinkage cracking potential. Test results indicated that the average steel strain and residual tensile stress were reduced as the thicker inner steel ring was used, whereas degree of restraint was increased. The steel strain, residual tensile stress and degree of restraint were hardly affected by the size of radius of inner ring. In the case of all ring specimens, shrinkage crack did not occur because the residual tensile stress was lower than the tensile strength. About 39~65% of the elastic shrinkage stress was relaxed by the sustained interface pressure, and the maximum relaxed stress was increased as the thicker inner ring was applied. Finally, the degree of restraint with age was predicted by performing non-linear regression analysis, and it was in good agreement with the test results.

• The Journal of Internal Korean Medicine
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• 제28권4호
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• pp.830-837
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• 2007

Background and purpose : Stroke is one of the most deadly diseases and a leading cause of disability. Lipids confer an increased risk for cardiovascular morbidity and mortality. In spite of many studies on the relationship between stroke and lipids, their relationship is not clear. This study was undertaken to determine whether lipids were associated with stroke. Method : We compared the components of blood lipids between stroke patients group (n=217,Cases), non-stroke control group (n=160, Controls) and healthy control group without hypertension, diabetes mellitus, ischemic heart disease, or hyperlipidemia (n=140, Normals). These data were statically analyzed by general linear models and binary logistic regression analysis to get each adjusted odds ratio. Result : The results were as follows. The blood levels of total cholesterol (T-Chol), triglyceride (TG) and low density lipoprotein cholesterol (LDL-Chol) were significantly higher in patients of ischemic stroke, while the blood levels of T-Chol and LDL-Chol were significantly lower, and the blood levels of TG significantly higher in patients of hemorrhagic stroke. The blood level of high density lipoprotein cholesterol (HDL-Chol) was significantly lower in all cases. Conclusion : These results suggest that high TG and low HDL-Chol may be risk factors of hemorrhagic stroke and ischemic stroke, high T-Chol and LDL-Chol may be risk factors of ischemic stroke, and low T-Chol and LDL-Chol may be risk factors of hemorrhagic stroke in Koreans.

• Journal of the Korea Concrete Institute
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• 제21권4호
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• pp.401-408
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• 2009

A compression lap splice becomes an important issue due to development of ultra-high strength concrete. Current design codes regarding compression lap splice do not utilize merits of the improved strength of ultra-high strength concrete. Especially, a compression lap splice can be calculated longer than a tension lap splice according to the codes because they do not consider effects of compressive strength of concrete and transverse reinforcement. This anomaly confuses engineers in practice. Design equation is proposed for compression lap splice in 40 to 70 MPa of compressive strength of concrete. The proposed equation is based on 51 specimens conducted by authors. Basic form of the equation includes main parameters which are derived from investigating test results. Through two-variable non-linear regression analysis of measured splice strengths, a strength equation of compression lap splices is then derived. A specified splice strength is defined using a 5% fractile coefficient and a lap length equation is constructed. By the proposed equation, the anomaly of lap lengths in tension and compression is got rid of. In addition, the equation has a reliability equivalent to those of the specified strengths of materials.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.314-322
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• 2017

Purpose: This study was conducted to investigate the hot air drying characteristics of squash slices depending on the drying conditions (input air velocity, input air temperature, and sample thickness). Methods: The developed drying system was equipped with a controllable air blower and electric finned heater, drying chamber, and ventilation fan. Squash (summer squash called Korean zucchini) samples were cut into slices of two different thicknesses (5 and 10 mm). These were then dried at two different input air temperatures (60 and $70^{\circ}C$) and air velocities (5 and 7 m/s). Six well-known drying models were tested to describe the experimental drying data. A non-linear regression analysis was applied to determine model constants and statistical indices such as the coefficient of determination ($R^2$), reduced chi-square (${\chi}^2$), and root mean square error (RMSE). In addition, the effective moisture diffusivity ($D_{eff}$) was estimated based on the curve of ln(MR) versus drying time. Results: The results clearly showed that drying time decreased with an increase in input air temperature. Slice thickness also affected the drying time. Air velocity had a greater influence on drying time at $70^{\circ}C$ than at $60^{\circ}C$ for both thicknesses. All drying models accurately described the drying curve of squash slices regardless of slice thickness and drying conditions; the Modified Henderson and Pabis model had the best performance with the highest R2 and the lowest RMSE values. The effective moisture diffusivity ($D_{eff}$) changes, obtained from Fick's diffusion method, were between $1.67{\times}10^{-10}$ and $7.01{\times}10^{-10}m^2/s$. The moisture diffusivity was increased with an increase in input air temperature, velocity, and thickness. Conclusions: The drying time of squash slices varied depending on input temperature, velocity, and thickness of slices. The further study is necessary to figure out optimal drying condition for squash slices with retaining its original quality.

• Journal of Digital Convergence
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• 제14권9호
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• pp.159-170
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• 2016

In this study, the authors examine the ways in which social media ultimately affects the attachment of individuals to their favorite brands. Through an analysis of data using multiple linear regression, this study finds that SNS (social networking site) users that post status updates for a wide audience have no bearing on the individual's use of socialization agents. Those who consume social news passively are, however, likely to depend on socialization agents for determining their final purchase decisions. Socialization agents, both personal and non-personal, also play a role in the formation of brand attachment among individuals who depend on these social sources. Based on these results, marketers are encouraged to establish an online footprint of a social nature to formulate brand awareness and to provide a means for users of social media to improve their brand attachments to their favored brands. As this research was conducted exclusively in the predominantly collective culture of South Korea, further studies could attempt to analyze social networking use and socialization agent use via a cross-culture study, particularly one including an individualistic culture.

• Journal of dental hygiene science
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• 제14권3호
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• pp.371-378
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• 2014

This study aims to evaluate the influence of vitamin and mineral supplement intake, and degree of calcium and phosphorus intake on occurrence of dental caries in primary teeth. Research data was derived from the Fourth Korean National Health and Nutrition Examination Survey (KNHANES) and 1,139 Korean children of 3 to 6 years were selected as subject for this study. The dft index, nutrition factor including vitamin or mineral supplement intake and degree of intake for calcium (Ca) and phosphorus (P) were identified. Chi-square test was performed to assess the difference in socioeconomic status, oral health behavior and nutrition factor, including vitamin or mineral supplement intake and degree of intake for Ca and P. Linear regression analysis was performed to identify the relationship between the dft index and the related variables. As a result, the dft index was increased with the age. Significant differences in Ca intake was examined according to the sex, and P intake was different according to the sex in 3-year-old group. Among the 4-year-old children, the vitamin and mineral supplement takers had 1.206 less dft index than the non-takers. In conclusion, intake of Ca, P and vitamin/mineral supplement was not a pivotal factor to influence the incidence of primary teeth caries. However, significantly low dft index was observed from 4-year-old group who intake vitamin or mineral.

• Journal of radiological science and technology
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• 제35권2호
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• pp.173-181
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• 2012

The aim of this study is to compare the geometric characteristics of the lung tumor, such as tumor centroid, HU change relative to breath phase, depending on tumor location and adhesion using 4DCT and deformable image registration program (MIMVista). The Y axis change was most significant and the mean Y axis centroid fluctuation was $7.32{\pm}6.88mm$ in lower lung tumor. The mean HU variation in lower lung mass has changed more than other locations, and its mean HU variation was $7.7{\pm}4.97%$ and non-adhered mass was more changed. Correlation for the mass volume between 3DCT and MIP was very high and its coefficient was 0.998. The effect of tumor location, adhesion and diaphragm excursion to geometric uncertainties was analyzed by linear regression model, it was influenced to mass deformation and geometrical variation so much except diaphragm excursion. but intra-fractional and inter-patient's uncertainties were great, so it couldn't find any exact deformation trend.

• Korean Journal of Soil Science and Fertilizer
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• 제38권2호
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• pp.66-71
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• 2005

Soil loss into stream and river by runoff shall be considered for non-point source pollution management as national land conservation. The purpose of this study was to develop the mathematical equation to predict soil loss from inclined uplands of maize cultivation due to the runoff by rainfall which mainly converges on July and August. Soil loss was concentrated on May because of low canopy over an entire field in 2002 and on June and July because of heavy rainfall in 2003. By regression analysis the relation between runoff and soil loss can be represented by a linear equation of y =1.5291x - 3.4933, where y is runoff ($Mg\;ha^{-1}$) and x is soil loss ($kg\;ha^{-1}$). The determination coefficient of this equation was 0.839 (P<0.001). Therefore, the mathematical equation derived from the practical experiment at the inclined upland can be applicable to predict soil loss accompanied by runoff due to periodic rainfall converging on short periods within a couple of months.

• Korean Journal of Radiology
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• 제22권3호
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• pp.464-475
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• 2021

Objective: This study aimed to evaluate the tumor doubling time of invasive lung adenocarcinoma according to the International Association of the Study for Lung Cancer (IASLC)/American Thoracic Society (ATS)/European Respiratory Society (ERS) histologic classification. Materials and Methods: Among the 2905 patients with surgically resected lung adenocarcinoma, we retrospectively included 172 patients (mean age, 65.6 ± 9.0 years) who had paired thin-section non-contrast chest computed tomography (CT) scans at least 84 days apart with the same CT parameters, along with 10 patients with squamous cell carcinoma (mean age, 70.9 ± 7.4 years) for comparison. Three-dimensional semiautomatic segmentation of nodules was performed to calculate the volume doubling time (VDT), mass doubling time (MDT), and specific growth rate (SGR) of volume and mass. Multivariate linear regression, one-way analysis of variance, and receiver operating characteristic curve analyses were performed. Results: The median VDT and MDT of lung cancers were as follows: acinar, 603.2 and 639.5 days; lepidic, 1140.6 and 970.1 days; solid/micropapillary, 232.7 and 221.8 days; papillary, 599.0 and 624.3 days; invasive mucinous, 440.7 and 438.2 days; and squamous cell carcinoma, 149.1 and 146.1 days, respectively. The adjusted SGR of volume and mass of the solid-/micropapillary-predominant subtypes were significantly shorter than those of the acinar-, lepidic-, and papillary-predominant subtypes. The histologic subtype was independently associated with tumor doubling time. A VDT of 465.2 days and an MDT of 437.5 days yielded areas under the curve of 0.791 and 0.795, respectively, for distinguishing solid-/micropapillary-predominant subtypes from other subtypes of lung adenocarcinoma. Conclusion: The tumor doubling time of invasive lung adenocarcinoma differed according to the IASCL/ATS/ERS histologic classification.