• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.313-320
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• 2013

The $AlAs_xSb_{1-x}$ step-graded buffer (SGB) layer was grown on the Silicon (Si) substrate to overcome lattice mismatch between Si substrate and $Al_{0.3}Ga_{0.7}As$/GaAs multiple quantum wells (MQWs). The value of root-mean-square (RMS) surface roughness for 5 nm-thick GaAs grown on $AlAs_xSb_{1-x}$ step-graded buffer layer was ~1.7 nm. $Al_{0.3}Ga_{0.7}As$/GaAs MQWs with AlAs/GaAs short period superlattice (SPS) were formed on the $AlAs_xSb_{1-x}$/Si substrate. Photoluminescence (PL) peak at 10 K for the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure showed relatively low intensity at ~813 nm. The RMS surface roughness of the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure was ~42.9 nm. The crystal defects were observed on the cross-sectional transmission electron microscope (TEM) images of the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure. The decrease of PL intensity and increase of RMS surface roughness would be due to the formation of the crystal defects.

• Journal of Nutrition and Health
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• v.45 no.4
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• pp.324-335
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• 2012

The purpose of this study was to examine the relationship of dietary self-efficacy and illness beliefs, perceived benefits, and perceived barriers for the reduction of sodium intake in the elderly. A cross-sectional study was performed on 252 elderly people, aged 65 yrs and above, living in Daejeon Metropolitan city and Jecheon city, Chungbuk from March 21 to March 30, 2011. Dietary self-efficacy of three factors (resisting relapse, reducing salt and behavioral skills), perceived benefits and barriers, accurate and inaccurate illness beliefs were measured by 5 or 4 point Likert scale. With the increasing education level of the elderly, dietary self-efficacy, and accurate illness belief score increased and perceived barrier score decreased. Perceived benefits score was higher in the subject living alone compared to those living with siblings or spouses. Among three factors of dietary self-efficacy, reducing salt was scored highest and behavioral skills scored lowest in the elderly. Recording meal diary and reading labels for salt content in the items of behavioral skills showed lower score than other items. Accurate illness beliefs and perceived benefits were more scored than inaccurate illness beliefs and perceived barriers respectively in the subjects. The subjects with higher accurate illness beliefs, lower inaccurate illness beliefs, higher perceived benefits, and lower perceived barriers for the reduction of sodium intake showed higher dietary self-efficacy. In summary, accurate illness beliefs and perceived benefits positively correlated with dietary self-efficacy for the reduction of sodium intake in the elderly, whereas inaccurate illness beliefs and perceived barriers are negatively correlated.

• 한국벤처창업학회:학술대회논문집
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• 2006.04a
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• pp.167-201
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• 2006

Korean corporations are transforming their vertical operational structure to a team-based structure to compete in the rapidly changing environment and for improved performance. However, a high percentage of the respondents in KBS said that despite the appearance of the present team structure, the organization operates much like a vertically-structured organization. This result can be attributed to the lack of study and implementation toward the goal of empowerment, the key variable for the success of the team-based structure. This study aims to provide policy suggestions on how to implement the process of empowerment, by investigating the conditions that hinder the process and the attitude of the KBS employees. For the cross-sectional study, this thesis examined the domestic and international references, conducted a survey of KBS employees, personal interviews and made direct observations. Approximately 1,200 copies of the Questionnaire were distributed and 474 were completed and returned. The analysis used SPSS 12.0 software to process the data collected from 460 respondents. For the longitudinal-study, six categories that were common to this study and "The Report of the Findings of KBS Employees' View of the Team Structure" were selected. The comparative study analyzed the changes in a ten-month period. The survey findings showed a decrease of 24.2%p in the number of responses expressing negative views of the team structure and a decrease of 1.29%p in the number of positive responses. The findings indicated a positive transformation illustrating employees' improved understanding and approval of the team structure. However, KBS must address the issue on an ongoing basis. It has been proven that the employee empowerment increases the productivity of the individual and the group. In order to boost the level of empowerment, the management must exercise new, innovative leadership and build trust between the managers and the employees first. Additional workload as a result of shirking at work places was prevalent throughout all divisions and ranks, according to the survey data. This outcome leads to the conclusion that the workload is not evenly distributed or shared. And the data also showed the employees do not trust the assessment and rewards system. More attention and consideration must be paid to the team size and job allocation in order to address this matter; the present assessment and rewards system need to be complemented. The type of leadership varies depending on the characteristics of the organization's structure and employees' disposition. KBS must develop and reform its own management, leadership style to suit the characteristics of individual teams. Finally, for a soft-landing of KBS team structure, in-house training and education are necessary.

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.176-188
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• 2009

Purpose : Peritoneal dialysis (PD) is the major form of dialysis in use for infants and children with end-stage renal disease (ESRD). The aim of this study was to gain insight into the current status of children on PD in Korea. Methods : In May 2008, questionnaires were sent to the pediatric nephrologists via e-mail. Four centers replied and those data were reviewed. Results : A total of 103 patients were included in this study. Male to female ratio was 1.6:1. Mean age was $11.5{\pm}4.9$ years (0-19 years). Primary renal diseases diagnosed were as follows: primary glomerular disease (34%), chronic pyelonephritis-reflux nephropathy (14.6%), systemic disease (9.7%), renal hypoplasia/dysplasia (8.7%), heredofamilial disease (6.8%), vascular disease (3.9%), drug-induced nephropathy (1.0%), and unknown (12.6%). PD modalities were as follows: CAPD (42.7%), CCPD (27.2%), NIPD (11.7%), and Hybrid (18.4%). Weekly total Kt/V was $2.1{\pm}0.7$ (0.3-4.1). Results of peritoneal equilibrium test were as follows: low 36.8%, low average 31.6%, high average 19.7%, and high 11.8%. Z-score for weight was $-1.00{\pm}1.20$ (-4.54~+2.50). Z-score for height was $-1.55{\pm}1.65$ (-9.42~+1.87). Growth hormone was administered in 24.3% of patients. Anti-hypertensive drugs were administered in 64.0% of patients. Laboratory findings were as follows: hemoglobin $10.5{\pm}1.4$ g/dL, calcium $9.7{\pm}0.7$ mg/dL, phosphorus $5.4{\pm}1.4$ mg/dL, and parathyroid hormone $324.2{\pm}342.8$ pg/mL. Conclusion : Primary glomerular disease was the most common cause of ESRD. CAPD was the most prevalent PD modality. Low and low average peritoneal transport type were common. Growth disturbance were noted in many patients. Some patients had hypertension even with anti- hypertensive drugs. Calcium-phosphorus levels were maintained adequately, but many patients had secondary hyperparathyroidism.

• Journal of Chest Surgery
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• v.42 no.1
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• pp.79-86
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• 2009

Background: Background: Computed tomography (CT) is the main tool for detecting abnormalities of the thoracic aorta, but conventional CT only shows the cross-sectional images. These CT images have some limitations fo accuratly measuring the thoracic aortic diameters at various levels. Multidetector computed tomography (MDCT) overcomes these limitations. We measured the thoracic aortic diameter perpendicular to the loop-shaped thoracic aortic course and this was studied in relation to age, gender, height, weight, the body surface area, the body mass index and the presence of hypertension. Material and Method: Thirty hundred thirty one patients (males: 141 patients and females: 190 patients) who had no abnormalities of the thoracic aorta were investigated using MDCT aortography. They were divided into three age categories: 20~39 years old, 40~59 years old and over age 60. The image was reformed with multiplanar reconstruction and the diameter of the aorta was measured perpendicular to the aortic course at 5 anatomic segments. Level A was the mid-ascending aorta, level B was the distal ascending aorta, level C was the aortic arch, level D was the aortic isthmus and level E was the mid-descending aorta. Result: The mean age was 49.5 years old for males and 54.9 years old for females (p<0.05). The mean diameter of the thoracic aorta at level A was 31.1 mm, that at level B was 30.2 mm, that at level C was 26.5 mm, that at level D was 24.0 mm and that at level E was 22.6 mm. The diameters at all the levels were gradually increased with age. Hypertensive patients had larger diameters than did the non-hypertensive population. There was a positive correlation between the ascending aortic diameter (levels A&B) and height and the body surface area, but there were no statistical differences at the aortic arch (level C) and the descending aorta (levels D&E). There were no statistical differences of the weight and body mass index at all levels. Conclusion: The diameters of the thoracic aortas were directly correlated with gender, age and hypertension. Height and the body surface area were only correlated with the ascending aorta. Weight and the body mass index have no statistical difference at all levels. We measured the age related thoracic aortic diameters and the upper normal limits and we provide this data as reference values for the thoracic aortic diameter in the Korean population.

• Korean Journal of Psychosomatic Medicine
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• v.17 no.2
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• pp.52-61
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• 2009

Objectives : The aim of this study was to assess health-related quality of life and evaluate the risk factors affecting severity of menopausal symptoms in early and late postmenopausal women based on the stages of reproductive aging workshop(STRAW) paradigm. Methods : This cross-sectional study examined 497 Korean postmenopausal women aged 41-59 years in Seoul and Gyeonggi province. We divided subjects into early postmenopause group and late postmenopause group. Menopause Rating Scale(MRS) was used to measure the quality of life. MRS scores, sociodemographic variables, smoking, alcohol use, age at menopause, and risk factors such as attitude to menopause, depression, history of premenstrual dysphoric disorder were compared between early and late postmenopause groups. Multiple regression analysis was performed in each group to assess the independent contribution of several variables. Results : Early postmenopause group showed significantly higher MRS scores, more negative attitude toward menopause, higher scores of depressive symptoms than late postmenopause group. Moderate to very severe hot flush group showed significantly, more negative attitude toward menopause, higher score of depressive symptoms, and higher MRS scores than none to mild hot flush groups. Depressive symptoms and attitude toward menopause contributed to the severity of menopausal symptom in both early and late postmenopause groups. Chronological age, age at menopause, history of PMDD contributed to severity of menopausal symptoms in early postmenopause group while marital status and occupation contributed in late postmenopause group. Conclusion : Health-related quality of life in postmenopause women was significantly lower in early postmenopause group than the late. Attitude toward menopause and depressive symptoms contributed significantly to quality of life in both early and late postmenopause groups but other variables contributed differently in each group. Further studies on clinical samples of postmenopausal women in order to confirm quality of life and its risk factor are needed to be done.

• Clinical and Experimental Pediatrics
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• v.50 no.9
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• pp.905-911
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• 2007

Purpose : Ghrelin, being secreted from the stomach, stimulates growth hormone secretion and controls energy homeostasis by increasing appetite. Leptin, being secreted from the adipocytes, controls weight and energy homeostasis by decreasing appetite. Leptin concentration is reported to increase after childhood cancer therapy. This study was aimed to compare ghrelin and leptin concentrations in normal children and children who received cancer therapy. Methods : We enrolled forty-three patients who were diagnosed with cancer and received radiotherapy or chemotherapy during Dec. 2004 through Dec. 2005 in St. Marys hospital and Kangnam St. Marys hospital. Forty-five healthy children were selected as a control group whose age, gender, weight and height were similar to those of cancer group. The serum leptin and ghrelin concentrations were also measured by radioimmunoassay. Results : The cancer group showed higher BMI and leptin concentrations. The control group showed higher concentrations of ghrelin. Both control and cancer groups revealed positive correlations between leptin concentrations and BMI. Ghrelin concentrations in the control group showed negative correlations with age, height, weight and BMI but no significant correlation was found in the cancer group. All the parameters in the group treated with chemotherapy only were not different from those in the group treated with chemotherapy and irradiation. But the level of ghrelin in the acute myeloid leukemia group was much higher than those in the acute lymphoblastic leukemia group. Conclusion : Patients with pediatric cancer treatment have presented higher BMI and leptin concentrations but lower ghrelin concentrations than those in healthy children. Because of the relatively short duration and cross sectional method of the study, however, further long term and prospective study will be required in the future.

• Korean Journal of Psychosomatic Medicine
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• v.18 no.2
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• pp.82-93
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• 2010

Objectives : The purpose of this study was to explore attitude and belief about menopause and severity of menopausal symptoms according to menopausal status. This study conducted a cross-sectional assessment of the effects of depressive symptoms and the severity of trait anxiety on the severity of menopausal symptoms. Methods : Participants were all outpatients at the psychiatric outpatient clinic of Korea University Guro Hospital. All participants, aged 40 to 64, had depressive or anxiety disorders and were divided into the premenopause, perimenopause, premenopause, and postmenopause groups. Menopause Rating Scale(MRS) was used to measure the severity of menopausal symptoms. The attitude toward menopause was examined by a self-report questionnaire regarding menopause. Beck Depression Inventory(BDI) and State-Trait Anxiety Inventory(STAI) were used to assess depressive symptoms and anxiety. Results : The severity of menopausal symptoms was not different among the groups according to menopausal status. There was a significant correlation between a negative attitude toward menopause and the severity of menopausal symptoms. Patients with moderate to severe depressive symptoms and trait anxiety had more severe menopausal symptoms. Conclusion : Negative attitude toward menopause, depressive symptoms, and anxiety had a significantly negative impact on the severity of menopausal symptoms. The results of this study suggest that treatment to relieve depressive symptoms and anxiety and intervention to reduce negative attitude toward menopause are required. Further studies with larger sample size are needed to evaluate potentially effects of depressive symptoms and anxiety on severity of menopausal symptoms in middle-aged female psychiatric patients.

• The Korean Journal of Malacology
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• v.30 no.3
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• pp.219-226
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• 2014

The effects of different stocking densities on the growth and survival rate of the abalone, Haliotis discus hannai, were investigated in marine net cage for two years. Stocking density was set 15, 30, 45 and 60 percentage $(=per.)/m^2$ with share to cross-sectional area per shelter. The primary rearing period (PRP) and the secondary rearing period (SRP) were conducted by a year. One year mean water temperature of PRP and SRS showed the difference about $2^{\circ}C$. In the growth (initial mean shell length of abalone : $36.14{\pm}2.28mm$) of PRP, the absolute growth rate (ARG), daily growth rate (DGR) and specific growth rate (SGR) of the $15per./m^2$ were higher than those of density groups (P < 0.05). Survival rates of all density groups were showed no significant difference. In the growth (mean shell length of abalone : $55.26{\pm}6.93mm$) of SRP, ARG, DGR and SGR of stocking density groups showed no significant difference except for $45per./m^2$ density group. Survival rate in the low-density (15, $30per./m^2$) was more than 70%, and those of the high-density (45, $60per./m^2$) were less than 31% and 9%, respectively. These results showed that the appropriate stocking density for $15per./m^2$ was seven hundred fifty number per one net cage ($2.4{\times}2.4m$), during PRP using 3-4 cm abalone in length. Also for the secondary rearing period, the optimal stocking density (shell length 5-6 cm of abalone) consider with the economical efficiency was determined to be $30per./m^2$, resulting the productivity improved.

• Journal of Yeungnam Medical Science
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• v.14 no.2
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• pp.314-328
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• 1997

A cross-sectional study was performed to evaluate the effects of chronic exposure to low-dose solvent on neurobehavioral performance of 48 male workers exposed to organic solvents. A control group of 50 workers was selected from same factories. Each worker completed a medical and occupational questionnaire and four tests of Neurobehavioral Core Test Battery. These included Benton visual retention test, digit symbol, digit span, and pursuit aiming. Comparison of mean performance showed a significantly poorer performance on digit symbol, digit span, and pursuit aiming. In univariate analysis, age contributed to poor performance on Benton visual retention test and educational level was found to reduce the performance on symbol digit in both groups. Amount of alcohol intake was found to reduce the performance on digit symbol and smoking appeared to slow pursuit aiming in the exposure group. In multiple regression analysis, controlling for age, educational level, alcohol, and smoking, Solvent exposure was found to be associated with performance of digit span, and number of correct dot of pursuit aiming. Age on Benton visual retention, educational level on digit symbol, arid smoking on pursuit aiming were found to be a significant factors on each test items. This study suggest that short-term memory, and perception can be affected easily by chronic exposure of organic solvents which air concentration levels were under the Threshold Limit Value.