• The Journal of Korean Society for Radiation Therapy
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• v.16 no.1
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• pp.1-9
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• 2004

Purpose : The aim of this study is to investigate the properties of small field size and to measure the penumbra and central axis depth dose varying to the jaw setting and off axis distance for indicate this data to small field sizes radiation therapy. Material and methods : The percentage depth dose, beam profile and central axis output dose was measured by farmer type ion chamber and pinpoint chamber using Primart linac with 6MV energy. Beam quality and penumbra variations according to the central axis shift, from center to every 2cm outside increment, and field size, from $1{\times}1cm$ to $10{\times}10cm$ was investigated and compared with that of the standard geometrical condition's results Results : The differences of measured values between two ion chamber was about $37\%$ at 10cm depth with $1{\times}1cm$ field sizes but as field size increased this differences was diminished gradually. Measured data from various off axis distance with the different asymmetric collimations are not changed significantly but as size decreased the dose variation was increased and at $1{\times}1cm$ field size dose difference among off axis distance was as much as $13\%$, and as shallower the measured depth the central axis dose variations among the OAD was increased, penumbra was not changed noticeably depending on off axis distance but the percentage of penumbra from its initial field sizes was strongly dependant on field sizes and penumbra occupation rates of its own field sizes ranging from $6\%$ at $10{\times}10cm$ to $50\%$ at $1{\times}1cm$ field size. Conclusion : For imrt treatment, there are several numbers of different gentry angles with beams of nonuniform fluences are required and several complex factors involved. Among them the characteristics of beam output varying to the geometrical setting and design of collimators are of important to attaining a good treatment results. As mentioned in results the differences of measured values are changed significantly depends on ion chamber volume, depths and field size. For providing quality radiation treatment, especially at small field size, those factor's should have considering deliberately.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.246-257
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• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering, Inc., Troy, USA) and ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Vivadent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition, Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.385-392
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• 2011

Although monoculture methods have been remarkably useful due to their simplicity, they have serious limitation because of the different types of cells communication with each other in many physiological situations. We demonstrated levels of markers of endothelial dysfunction such as tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and interleukin-1$\beta$ (IL-1$\beta$) as well as stimulation of receptor of advanced glycation endproducts (AGEs) on monoand co-culture system such as only monocyte (THP-1) cultivation system, only endothelial cell (HUVEC) cultivation system, and co-cultivation system of THP-1 and HUVEC. The mRNA levels of TNF-$\alpha$ and IL-1$\beta$ on HUVEC increased by the co-culture with monocyte after 4 hr at 100 ${\mu}g/mL$ glyceraldehyde-AGE. The secreted protein contents into medium of TNF-$\alpha$ and IL-1$\beta$ increased after 8 hr approximately 2~2.5 times compared to mono-cultivation. In contrast, the mRNA level of receptor of AGE (RAGE) was relatively insensitive on the co-culture system. The mediators by which monocytes activate endothelial cell have not been fully elucidated. In this study we confirmed production of soluble cytokines such as TNF-$\alpha$ and IL-1$\beta$ by monocytes. Use of monocyte conditioned medium, which contains both cytokines, can activate endothelial cell.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.289-297
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• 2020

The purpose of this study was to investigate the prevalence of back pain and the variables related to back pain in physiotherapists. In order to investigate the variables related to the incidence of back pain, The results were as follows : 1. Physical therapists' low back pain occurrence possibility appeared by whole 55.0% by male 11.0% and female 44.0%. 2. A day by people's work environmental special quality with low back pain treat morbidity to 31~40 people 40.0%, office hours per week by 45~49 hours 49.1%, a day stand-up tome be less than 5~7 hours 36.4% and appeared the highest. 3. Case that respond "Do dissatisfaction" to profession which is physical therapists' special psychological quality examined by people's 67.0% which low back pain. 4. Cause of low back pain in special active quality to get low back pain is the highest by case 38.2% that respond is "Special cause does not know, it is because for a long time worked to physical-therapy, and the reason that play waist softness gymnastics examined the highest by case 45.4% that respond is "Because present low back pain serves to be or prevents flare-up." According to result of this research, we could Know physical therapists are professionally endanger of getting low back pain. Specially, we could say physical therapists' low back pain occurrence possibility is high because of their having an experience or regarding work environmental special quality such as a day treatment morbidity, office hours per week, stand-up time for a day. There, educational programs need to improve of work environment and prevent the recurrence of low back pain. In this research, we recognized various variables of physical therapists' low back pain occurrence possibility are related to direct causal connection of low back pain occurrence, but we think continuous research should be tired forward in reply.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.4
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• pp.9-21
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• 2008

In this paper, we propose a GNSS-based RF receiver, A high precision localization architecture, and a high sensitivity localization architecture in order to solve the satellite navigation system's problem mentioned above. The GNSS-based RF receiver model should have the structure to simultaneously receive both the conventional GPS and navigation information data of future-usable Galileo. As a result, it is constructed as the multi-band which can receive at the same time Ll band (1575.42MHz) of GPS and El band (1575.42MHz), E5A band (1207.1MHz), and E4B band (1176.45MHz) of Galileo This high precision localization architecture proposes a delay lock loop with the structure of Early_early code, Early_late code, Prompt code, Late_early code, and Late_late code other than Early code, Prompt code, and Late code which a previous delay lock loop structure has. As we suggest the delay lock loop structure of 1/4chips spacing, we successfully deal with the synchronization problem with the C/A code derived from inaccuracy of the signal received from the satellite navigation system. The synchronization problem with the C/A code causes an acquisition delay time problem of the vehicle navigation system and leads to performance reduction of the receiver. In addition, as this high sensitivity localization architecture is designed as an asymmetry structure using 20 correlators, maximizes reception amplification factor, and minimizes noise, it improves a reception rate. Satellite navigation system repeatedly transmits the same C/A code 20 times. Consequently, we propose a structure which can use all of the same C/A code. Since this has an adaptive structure and can limit(offer) the number of the correlator according to the nearby environment, it can reduce unnecessary delay time of the system. With the use of this structure, we can lower the acquisition delay time and guarantee the continuity of tracking.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.319-332
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• 2009

The present study was performed to analyze the life style and eating behavior of stroke patients and to find the risk factors related to stroke incidence in Daegu and Gyeongbuk Province, Korea. The case subjects (n=100) were selected from newly diagnosed stroke patients at Kyungpook National University Hospital. The control subjects (n=150) were selected from community inhabitants who did not have stroke history and were sex and age-matched with the case subjects. The survey was conducted by individual interviews using questionnaires on the general characteristics, life-style, eating behavior, food intake frequency and food preference. The high body mass index, preexisting diseases such as diabetes and hypertension, stroke family history, smoking, overeating habit and high preference for sweet, greasy and meat foods appeared to be the risk factors for stroke incidence. On the other hand, the results suggest that life style of regular exercise and nonsmoking, food habits of green tea drinking and enough chewing, preference for Korean meal type, high intake frequency for legumes, vegetables, mushrooms, seaweeds, fishes and shell fishes, soy milk and green tea might be the protective factors for the stroke. Therefore, maintenance of healthy weight, the prevention and management of the deteriorative chronic diseases, change of life style and improvement of eating behaviors are considered to be important for stroke prevention.

• Journal of The Korean Association For Science Education
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• v.23 no.5
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• pp.517-530
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• 2003

The purpose of this study is to find out a model to explain the process of students' science-related career choice by identifying the causal relationships between science career choice and related factors. Important factors of science-related career choice were identified through factor analysis. 'Perception about career related to science', 'preference for science learning' and 'participation in science related activity' were three main factors of science-related career choice. A questionnaire was developed to know the factors of students' science-related career choice, and so as to make it possible to be analysed by structural equation modeling. The subject were 947 grade 6, 9, and 11 students in Seoul. Numbers of boys and girls in each grade was almost same. According to the structural equation modeling, 4 corrected models were obtained. In all 4 corrected models, 'perception about career related to science' had direct influence, and 'preference for science learning' and 'participation in science related activity' had indirect influence on science-related career choice. In the most fitting model. 'perception about career related to science' had an effect on science-related career choice with standardized total effect coefficient 1.03(direct effect 0.82, indirect effect 0.21). 'Preference for science learning', which influence 'participation in science related activity', had an effect on science-related career choice with standardized indirect effect coefficient 0.65. 'Participation in science related activity', which influence 'perception about career related to science'. had an effect on science-related career choice with standardized indirect effect coefficient 0.79. The implication to school science education is that it is most effective to raise the 'perception about career related to science' in order to make more students choose science related career. It is also effective to have more students participate in science related activity and enhance the preference for science learning. To explain the process of science related career choice more fully, it is necessary to build a more comprehensive model containing more factors influencing science-related career choice. It is necessary to test and complement the structural equation model by enlarging the subject to science high school students and science related college students.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.66-76
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• 1997

Objectives : The purpose of this study is to analyse sleep habits and sleep disorders in the elderly population ased 65-84 years. Methods : Epidemiological survey was performed at home by means of semi structured interviews in the city of Pusan, Korea. Subjects were randomly selected. The questionnaire consisted of 128 items including demographic findings, sleep habits, sleep disorders, somatic illnesses, and psychological distresses. Results : (1) The mean retiring time was 10.28 h (SD 1.30 h) and the mean wake-up time was 5.24 h (SD 1.33 h). The mean duration of sleep was 5.63 h (SD 1.80 h). The mean sleep onset time was 44.51 min. The mean frequency of daytime napping was 2.49 (SD 3.23). The subjects reported they woke up an average of 2.05 (SD 1.59) times per night. All of the above results were not related to age or gender. However, the mean frequency of difficulty in initiating/maintaining sleep was 2.2 times for men and 3.2 times for women (p<0.05). (2) The prevalence of insomnia was 57.7% and was not related to age or gender. Difficulty in initiating sleep was the most commonly reported insomnia complaint(52.4%). Early morning awakening was reported by 50.0% of patients and difficulty in maintaining sleep was reported by 45.1% of them. Worrying in bed and physical pain were strong contributing factor to insomnia. Conclusions : The results of our study showed several characteristics of sleep habits in the elderly. Sleep disorder in old age is not inevitable or trivial. Since sleep disturbance in older adults is common and distressing, it has implications for general health and well-being. Active concern and therapeutic intervention for the sleep habits and sleep disorders in the elderly are needed.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.179-188
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• 2000

Background : The decision to institute mechanical ventilation for patients with COPD is very difficult. The accurate information regarding weaning success and long-term survival will improve communication with patients and family and enhance informed consent. The aims of this study are to describe outcomes and identify variables associated with survival for patients experiencing mechanical ventilation with an acute respiratory failure of COPD. Methods : The 53 cases of mechanical ventilation in the intensive care unit in the National Medical Center from 1989 to 1998 were included. Data were collected retrospectively from medical records. Weaning success rate and 3 month and 1 year survival rates were estimated. Factors associated with weaning success and survival were determined. Results : Weaning sucess was 55%. For success group with 29 cases, 3 months survival rate was 61% and 1 year survival rate 37%. APACHE II scores in weaning success group were significantly lower than those in the failure group. Factors such as age, sex, comorbid-illnes. previous steroid use, causes of respiratory failure, RVH or arrhythmia on EKG, serum albumin level, arterial blood pH, $PaO_2$, $PaCO_2$, $FEV_1$ duration of mechanical ventilation and steroid use during mechanical ventilation were not associated with weaning success. Only age and serum albumin level were associated with 3 month and 1 year survival. No COPD patients of age more than 75 years and serum albumin level less than 3g/dl had survived at 1 year after weaning success. Conclusion : While weaning success from mechanical ventilation can be predicted by APACHE II score in COPD patients, long-term outcomes of survivors may be influenced by nutritional status and age.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.538-543
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• 2011

This study was conducted for the antihyperlipidemic effect of ethanol extract from Portulaca oleracea in high fat diet-induced obese mice after having injected the ethanol extract from Portulaca oleracea to the obese mice with high fat diet. The 30 six-week-old male C57BL/6J mice were divided into 3 groups of 10 and fed for 5 weeks to be obese with high fat diet. Thereafter, for 4 weeks, ethanol extract from Portulaca oleracea was provided through oral injection to the 3 groups: control group (HFD), group injected with 75 mg/kg of ethanol extract from Portulaca oleracea (HFD+POE 75) and the group injected with 125 mg/kg of ethanol extract from Portulaca oleracea (HFD+POE 125). The serum and liver lipid and the alanine transaminase (ALT) and aspartate transaminase (AST) activity were measured. The result showed that there was no significant difference in weight gain and feed intake, and the feed efficiency ratio was significantly low in the group provided with ethanol extract from Portulaca oleracea. Serum total cholesterol was significantly low in the group of ethanol extract from Portulaca oleracea (HFD+POE 125). It appeared that all the groups provided with ethanol extract from Portulaca loeracea reduced plasma triglyceride significantly according to the ethanol extract from Portulaca oleracea dose. There was no dose dependency of HDL-cholesterol to the dose of ethanol extract of Portulaca oleracea. LDL-cholesterol was low in the group dosed with high ethanol extract from Portulaca oleracea (HFD+POE 125). There was difference of total cholesterol, triglyceride and total lipid contents in liver. AI (atherogenic index) and CRF (cardiac risk factor) were significantly low in the group with high dose of ethanol extract from Portulaca oleracea (HFD+POE 125). There was no difference of serum AST activity, however, serum ALT activity was significantly low in the group with high dose of ethanol extract from Portulaca oleracea (HFD+POE 125).