• The Journal of the Korean bone and joint tumor society
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• v.19 no.1
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• pp.9-13
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• 2013

Purpose: We evaluated oncologic outcomes of chondrosarcomas and analyzed the disease-free survival rate of chondrosarcomas according to the various factors. Materials and Methods: We performed a retrospective study for the disease-free survival rate of 48 chondrosarcomas, 44 of which underwent surgical treatment and followed up more than 18 months since 1993, and in the remaining 4 cases, the patients died before 18 months after surgery. The vsariables were location, tumor volume, histologic grade, stage, age at presentation and treatment performed. The mean follow up period was 43.8 months (1-196 months). Results: The overall disease-free survival rate was 77.1% at mean 43.8 month follow up. The 5 year- and 10 year disease-free survival rates were 64% and 58% respectively. The histologic grade, stage, age at presentation revealed statistical significance on disease-free survival. All 9 patients treated with extended curettage for grade 1 central chondrosarcomas revealed disease-free survival with excellent functional outcome. Conclusion: The disease-free survival rate of chondrosarcomas mainly depended on histologic grade, stage and age at presentation. Local recurrence and distant metastasis also revealed statistically significant differences of disease-free survival rate. Comparing to wide resection, extended curettage for low-grade central chondrosarcomas in extremities were efficient methods with similar survival rate and less functional losses and complications.

• Journal of agricultural medicine and community health
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• v.33 no.1
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• pp.90-100
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• 2008

=Objectives: The aim of this study was to investigate the smoking rate and the related factors to early smoking of high school students.Methods: A questionnaire was administered to 920 students in 3 high schools in Daegu Metropolitan Results: Of total respondents, 1.8% had experience of smoking. Of those, 20.2% citied curiosity, 9.0% cited upon recommendation of friends, and 6.2% cited stress management as the main reason for their smoking. Separately, 53.1% responded habitually and 26.5% responded stress management as the main reason for continuing smoking. Of total former smokers, 68.4% said 'worry about their health' as the main reason for quitting smoking. Of those who failed to quit smoking, 58.7% cited 'weakness of will' as the main reason for their failure. Of total respondents, 10.8% were smoking currently. 'Smoking of family member'(p<0.01) and 'intent to smoke'(p<0.05) were significantly associated to early smoking of the subjects.In multivariate logistic regression analysis, 'higher levels of stress' and 'smoking of family member' were significant related factors to early smoking.Conclusions: Amid growing number of early smokers, it is imminent to identify the actual state of discourage smoking. In addition, education programs need to be developed to assist early smokers in quitting smoking and prevent smoking among youth.

• Sleep Medicine and Psychophysiology
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• v.24 no.2
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• pp.86-96
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• 2017

Objectives: This study aimed to analyze causality among sleep apnea, depression and cognitive function in patients with obstructive sleep apnea. Methods: We reviewed the medical records of 105 patients with sleep apnea and snoring who underwent overnight polysomnography (PSG). We analyzed various biological data, sleep variables (sleep duration and percentage) and respiratory variables [arousal index (AI), periodic leg movement index (PLM index), snoring Index (SI), mean SpO2, minimum SpO2, apnea-hypopnea index (AHI), and respiratory disturbance index (RDI)]. We also analyzed various data by sleep, cognition, and mood related scales: Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), snoring index by scale (SIS), Montreal Cognitive Assessment-Korean (Moca-K), Mini-mental State Examination-Korean (MMSE-K), clinical dementia rating (CDR), and Beck Depression Inventory (BDI). We analyzed causation among sleep, and respiratory, mood, and cognition related scales in obstructive sleep apnea patients. We analyzed the mediating effects of depression on sleep apnea patient cognition. Results: As Duration N1 increased and Total sleep time (TST) decreased, MOCA-K showed negative causality (p < 0.01). As BDI and supine RDI increased, causality was negatively related to MOCA-K (p < 0.01). As PSQI (p < 0.001) and SIS (p < 0.01) increased and as MMSE-K (p < 0.01) decreased, causality was positively related to BDI. BDI was found to mediate the effect of age on MOCA-K in patients with obstructive sleep apnea. Conclusion: Duration N1, total sleep time, BDI, and supine RDI were associated with cognitive function in obstructive sleep apnea patients. Depression measured by BDI partially mediated cognitive decline in obstructive sleep apnea patients.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.269-282
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• 2007

The purpose of this study is to investigate the causes of the dramatic process in forest policies from July of 1972 to June of 1973. In 1972, the core forest problem calling for an immediate solution was the severe forest degradation such as a low growing stock ($11m^3/ha$) and lots of non-tree forest land corresponding to 12% of total forest land. There could have been various approaches to solve the problem at that time. By the end of 1972, the Korean government was afoot to choose the management-oriented approach to carry out reforestation as a part of forest management. In order to implement this approach, the Korean government established the Forest Development Law enforcing establishment of the Forest Management Corporation as a public organization to carry out forest management in the special development land. However, the Korean government changed the management-oriented approach into the administration-oriented approach to carry out reforestation as a part of forest greening in order to rehabilitate severe degraded forests as soon as possible in early 1973. The Forestry Administration (refer to Forest Service) was transferred from the Department of Agriculture and Forestry to the Department of Interior for the efficient rehabilitation in advance, before the 1st 10-year National Greening Project. After the organization's transfer, the government established the 1 st 10-year National Greening Project aiming to reforest one million ha from 1973 to 1982 to use activities like the national greening campaign and the administrative organization mobilization including police force. Reforestation policy as a part of forest management lost effect due to the greening-oriented approach choice. Moreover, the Government struggled to provide 20 billion won for the establishment of the Forest Management Corporation. After all, on March 5th of 1973, the management-oriented approach dropped a curtain deleting the clauses defining the establishment of the Forest Management Corporation. Park, Chung-hee who was the then president of Korea might have felt the 'time restriction' to lose no time to habilitate degraded forests. Due to his awareness, the approach regarding reforestation was changed into administration-oriented activities. The president's awareness was considered as an invisible cause at that time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.633-643
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• 2013

This study investigated the efficiency of university foodservice operations by analyzing the effect of consumer's perception towards university foodservice quality. University students in the Jeonnam area were surveyed and 571 out of 700 surveys were chosen (response rate: 97.0%). SPSS (ver. 20.0) was used to conduct descriptive analysis, factor analysis, reliability analysis, t-test, and multiple regression analysis. The results show that 21.9% of university students have never used the university foodservice, while 48.7% of university students have eaten there 1~2 times per week. The most common reasons reported for avoiding the university foodservice were a limited menu selection (51.5%) and an untasty food (45.8%). The perception of overall service quality at the university foodservice scored relatively low (3.01 points), compared with its importance (3.89 points). The food taste, menu variety, and quality of food ingredients are factors that require improvement for operational strategies by the importance-performance analysis (IPA). The food factors (taste, variety, and quality) among university foodservice qualities had a significantly positive effect on consumers' overall satisfaction (p<0.001), perceived value (p<0.01), intent to recommend (p<0.001), and intent to revisit (p<0.01). These result indicate that the university foodservice management should focus on developing food factors and strive to meet the needs of university students through continuous customer surveys.

• Progress in Medical Physics
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• v.17 no.2
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• pp.105-113
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• 2006

This study peformed to confirm the corrected dose In different electron density materials using the superposition/FFT convolution method in radiotherapy Planning system. The experiments of the $K_2HPO_4$ diluted solution for bone substitute, Cork for lung and n-Glucose for soft tissue are very close to effective atomic number of tissue materials. The image data acquisited from the 110 KVp and 130 KVp CT scanner (Siemes, Singo emotions). The electron density was derived from the CT number (H) and adapted to planning system (Xio, CMS) for heterogeneity correction. The heterogeneity tissue phantom used for measurement dose comparison to that of delivered computer planning system. In the results, this investigations showed the CT number is highly affected in photoelectric effect in high Z materials. The electron density in a given energy spectrum showed the relation of first order as a function of H in soft tissue and bone materials, respectively. In our experiments, the ratio of electron density as a function of H was obtained the 0.001026H+1.00 in soft tissue and 0.000304H+1.07 for bone at 130 KVp spectrum and showed 0.000274H+1.10 for bone tissue in low 110 KVp. This experiments of electron density calibrations from CT number used to decide depth and length of photon transportation. The Computed superposition and FFT convolution dose showed very close to measurements within 1.0% discrepancy in homogeneous phantom for 6 and 15 MV X rays, but it showed -5.0% large discrepancy in FFT convolution for bone tissue correction of 6 MV X rays. In this experiments, the evaluated doses showed acceptable discrepancy within -1.2% of average for lung and -2.9% for bone equivalent materials with superposition method in 6 MV X rays. However the FFT convolution method showed more a large discrepancy than superposition in the low electron density medium in 6 and 15 MV X rays. As the CT number depends on energy spectrum of X rays, it should be confirm gradient of function of CT number-electron density regularly.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.1-6
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• 2014

Purpose : $T_2{^*}$ relaxation time which includes susceptibility information represents unique feature of tissue. The objective of this study was to investigate $T_2{^*}$ relaxation times of the normal glandular tissue and fat of breast using a 3T MRI system. Materials and Methods: Seven-echo MR Images were acquired from 52 female subjects (age $49{\pm}12 $years; range, 25 to 75) using a three-dimensional (3D) gradient-echo sequence. Echo times were between 2.28 ms to 25.72 ms in 3.91 ms steps. Voxel-based $T_2{^*}$ relaxation times and $R_2{^*}$ relaxation rate maps were calculated by using the linear curve fitting for each subject. The 3D regions-of-interest (ROI) of the normal glandular tissue and fat were drawn on the longest echo-time image to obtain $T_2{^*}$ and $R_2{^*}$ values. Mean values of those parameters were calculated over all subjects. Results: The 3D ROI sizes were $4818{\pm}4679$ voxels and $1455{\pm}785$ voxels for the normal glandular tissue and fat, respectively. The mean $T_2{^*}$ values were $22.40{\pm}5.61ms$ and $36.36{\pm}8.77ms$ for normal glandular tissue and fat, respectively. The mean $R_2{^*}$ values were $0.0524{\pm}0.0134/ms$ and $0.0297{\pm}0.0069/ms$ for the normal glandular tissue and fat, respectively. Conclusion: $T_2{^*}$ and $R_2{^*}$ values were measured from human breast tissues. $T_2{^*}$ of the normal glandular tissue was shorter than that of fat. Measurement of $T_2{^*}$ relaxation time could be important to understand susceptibility effects in the breast cancer and the normal tissue.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.210-216
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• 2008

In this study, image comparisons were carried out using a MRI contrast medium which was derived by mixing a polyaminocarboxylic ligand and a gadolinium (III) transition metal which is paramagnetic and has good neutron absorbing capabilities with Gd-DTPA which is currently being used widely in the clinical setting. By using a 1.0T (Harmony, SIEMENS) MR equipment, phantoms of which 100cc of saline was diluted with a diethylenetriaminetriacetic acid derivative and Gd-DTPA were imaged. The amount of diethylenetriaminetriacetic acid and Gd-DTPA which was diluted into the 100cc of saline was 0.05mmol/L, 0.1mmol/L, 0.15mmol/L, 0.2mmol/L, 0.3mmol/L, 0.5mmol/L, 1.0mmol/L, 2.0mmol/L, 3.0mmol/L and 4.9mmol/L respectively. Head coils were used and while fixing the SE pulse sequence and image variable (as TE is 14ms, 1NEX with a 256x201 matrix), the signal intensity and simple contrast ratios according to changing concentrations and TR were compared with various TR at 300ms, 400ms, 500ms, 600ms, 700ms, 800ms, 900ms, 1000ms, 1200ms, 1400ms and 1600ms. According to the comparison results of the signal intensity of the image based on changes in contrast medium concentrations and TR, the differences in signal intensity between the two contrast mediums were found to be small at $1.0{\sim}2.0mmol/L$ when the highest signal intensity was achieved. However, at concentrations of 1.0mmol/L or less, the signal intensity was markedly higher in the Diethylenetriaminetriacetic acid derivative than in the Gd-DTPA complex. It was also found that the differences in the signal intensities demonstrated by the concentrations of the contrast mediums were affected by the TR. Accordingly, the efficacy of the Diethylenetriaminetriacetic acid derivative was shown to be better than the Gd-DTPA and also possible to get the optimum image quality by the use of an appropriate TR with appropriate concentrations of contrast medium.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.143-147
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• 2005

Purpose : The aim of the this study was to evaluate the effect of various perinatal conditions on TSH and thyroid hormone levels in cord blood. Methods : Cord blood samples were collected from 130 neonates immediately after birth. TSH, $T_3$, and free $T_4$ levels were measured by the radioimmunoassay(RIA) method. The effects of gestational age, sex, birth weight, delivery method, perinatal asphyxia, maternal diabetes mellitus(DM), and preeclampsia on TSH and thyroid hormone levels were assessed by ANOVA test, Student t-test, and multiple regression analysis. Results : Birth weight and sex did not affect TSH and thyroid hormone levels. TSH level increased according to gestational age(P<0.05). TSH level was $4.42{\pm}0.66{\mu}IU/mL$ in infants born vaginally, which was higher than that of cesarian section delivery($3.31{\pm}0.33{\mu}IU/mL$)(P<0.05). TSH level was $5.18{\pm}0.93{\mu}IU/mL$ in asphyxiated newborns and $2.97{\pm}0.84{\mu}IU/mL$ in non-asphyxiated newborns(P<0.05). TSH level in infants with maternal DM($8.911{\pm}1.25{\mu}IU/mL$) was higher than that of infants without maternal DM($4.32{\pm}0.42{\mu}IU/mL$)(P<0.05). TSH level was $5.28{\pm}0.42{\mu}IU/mL$ in infants with maternal preeclampsia and $3.65{\pm}0.46{\mu}IU/mL$ in infants without maternal preeclampsia(P<0.05). Thyroid hormones were lower in infants with perinatal asphyxia(P<0.05). In asphyxiated infants, $T_3$ level was $75.33{\pm}55.65ng/mL$ and free $T_4$ was $0.54{\pm}0.21ng/mL$. $T_3$ and free $T_4$ level was $109.85{\pm}41.77ng/mL$ and $0.76{\pm}0.22ng/mL$ each in infants without perinatal asphyxia. Among the perinatal factors, gestational age, 1 min Apgar score and maternal DM influenced TSH level independently. Conclusion : In our study, cord blood TSH and thyroid hormone levels were affected by perinatal stress events.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.49-59
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• 1985

Formulation of the geometric optimization for truss structures based on the elasticity theory turn out to be the nonlinear programming problem which has to deal with the Cross sectional area of the member and the coordinates of its nodes simultaneously. A few techniques have been proposed and adopted for the analysis of this nonlinear programming problem for the time being. These techniques, however, bear some limitations on truss shapes loading conditions and design criteria for the practical application to real structures. A generalized algorithm for the geometric optimization of the truss structures which can eliminate the above mentioned limitations, is developed in this study. The algorithm developed utilizes the two-phases technique. In the first phase, the cross sectional area of the truss member is optimized by transforming the nonlinear problem into SUMT, and solving SUMT utilizing the modified Newton-Raphson method. In the second phase, the geometric shape is optimized utilizing the unidirctional search technique of the Rosenbrock method which make it possible to minimize only the objective function. The algorithm developed in this study is numerically tested for several truss structures with various shapes, loading conditions and design criteria, and compared with the results of the other algorithms to examme its applicability and stability. The numerical comparisons show that the two-phases algorithm developed in this study is safely applicable to any design criteria, and the convergency rate is very fast and stable compared with other iteration methods for the geometric optimization of truss structures.