• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.37-43
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• 2013

Purpose: The present study was conducted to investigate whether the directions of eye movement in playing computer games for certain period affected the change of near point of convergence (NPC) and fusional reserve (FR) or not. Methods: Total 40 subjects in 20s who have the visual acuity of 1.0 or higher without any ocular disease and accommodative dysfunction were asked to successively play computer games. After the subjects were moving eyes in horizontal and vertical directions for 40 and 90 minutes, their horizontal fusional reserves, vertical fusional vergence and near point of convergence were measured. Results: The near point of convergence showed a tendency to be receded after computer gaming in the horizontal and vertical directions, and both of horizontal and vertical fusional reserves were significantly reduced. The range of declined fusional reserves and receded near point of convergence after computer gaming for 90 minutes was smaller than those after computer gaming for 40 minutes. The change of binocular vision was affected by the horizontal eye movement rather than the vertical movement when analyzed by the direction of eye movement. Conclusions: This study revealed that the change in FR and NPC was different along with dominant direction of eye movement during visual display terminal (VDT) tasks. Therefore, the adjustment of VDT working time is required to prevent the dysfunction of binocular vision according to the dominant direction of eye movement during VDT task.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.33-39
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• 2002

The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal). Therefore, we examined visual fatigue by a questionnaire and measured frequency of blinking, tear film break-up time(BUT), height of palpebral fissure, visual acuity, refraction with retinoscopy and accommodation before and after two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 34%. In the visual symptoms, blurred vision was the highest rate of 83% and in case of systemic symptoms, shoulder pain was 38% marked top ranking but other symptoms were also distributed similar rate. The frequency of blinking during VDT work decreased significantly comparing with the one at rest. The average frequency of blinking is 8/min during VDT work and 22/min at rest. The BUT measured immediately after VDT work decreased much more than in the resting state. The average BUT was 7sec immediately after VDT work and 12sec at rest. The height of palpebral fissure during VDT work increased significantly comparing with the value at rest. The average height of palpebral fissure was 7.69mm at rest and 9.04mm during VDT work. The average visual acuity decreased almost 9.5% from 0.63 to 0.57, but refraction with retinoscopy increased about 0.28D to the direction of myopic shift. The amplitude of accommodation decreased approximately 1.49D from 7.98D to 6.49D and this resulted from the prolongation of near point of accommodation. Near point of convergence also was prolongated from 9.45cm to 10.30cm after VDT work.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.77-77
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• 2013

최근의 산업활동에서는 신규 원료 개발과 생산 효율성을 높이기 위하여 분체 공정이 증가하고 있는데, 미세 분진의 취급으로 분진운의 형성과 착화가 용이해지므로 분진폭발이나 화재 위험성이 증가하고 있다. 분진을 안전하게 사용하고 저장, 취급하기 위해서는 착화 전의 위험성 지표로서 최저발화온도(MIT ; Minimum Ignition Temperature)를 사전에 파악해 두는 것이 중요하다. 분진농도의 발화온도는 장치 내의 발화위험성이나 분진 취급 공정의 사고예방대책 관리를 위한 실용적 관점에서 중요하게 활용되는 폭발특성값이다. 또한 분진의 발화온도는 분진농도에 의존하며 농도변화에 따른 가장 낮은 온도를 MIT라고 한다. 본 연구에서는 화재폭발사고 빈도가 줄지 않고 있는 Mg 및 Mg-Al합금(60:40 wt%, 50:50 wt%, 40:60 wt%)을 대상으로 조성비율에 따른 최저발화온도를 실험적으로 조사하였다. Mg 및 Mg-Al(60:40 wt%), Mg-Al(50:50 wt%), Mg-Al(40:60 wt%) 시료의 평균입경은 142, 160, 151, $152{\mu}m$이다. MIT실험장치는 IEC 61241-2-1(Methods for Determining the Minimum Ignition Temperatures of Dust, 1994)에 준거하여 제작하여 사용하였다. 실험장치는 가열로, 분진운 시료홀더, 온도조절장치, 압축공기 제어장치 등으로 구성되어 있다. 구체적인 실험방법은 시험분진를 분진홀더에 장착하고 0.5 bar의 압축공기를 0.3 sec 동안 사용하여 일정 온도로 가열된 로의 내부로 분진운을 부유시킬 때에 분진운이 발화하여 가열로 하단부의 개방구에까지 화염이 전파하는지를 디지털비데오카메라로 기록, 평가하여 발화 유무를 판정하였다. Mg합금에 대한 MIT를 측정한 결과 $740^{\circ}C$가 얻어졌으며, Mg-Al(60:40 wt%)의 MIT는 $820^{\circ}C$로 조사되었다. 그러나 Mg-Al(50:50 wt%) 및 Mg-Al(40:60 wt%)에 대해서는 최대 가열로의 설정온도를 $890^{\circ}C$까지로 하여 농도를 변화시키면서 조사하였으나 발화가 일어나지 않았다. 문헌에 따르면 Mg입자 표면의 산화피막은 다공성으로 일정 온도에서 산화반응이 시간에 따라 직선적으로 증가하는데 반하여, Al의 산화피막은 보호 작용을 하여 일정 온도에서 산화반응속도가 표면과 내부의 농도 기울기에 의한 확산속도에 의존한다고 보고하고 있다. 본 연구결과를 토대로 Mg-Al합금의 발화특성을 고찰해 보면, Mg-Al합금에서 자기 전파성이 작은 Al성분의 증가는 착화지연이 증가하여 연소성이 감소하여 최저발화온도의 증가로 이어지는 것으로 추정되었다. 또한 발화온도는 주어진 조건의 온도장에서 분진이 존재하는 시간 길이에 따라 변화하므로, 발화온도를 실험적으로 측정하는 경우에는 측정장치나 방법에 따라 달라지므로 사업장의 현장에 발화온도를 적용하는 경우에는 장치 내의 분진의 존재시간을 고려할 필요가 있다.

• Journal of Oral Medicine and Pain
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• v.26 no.3
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• pp.261-276
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• 2001

본 연구는 구강안면동통 중에서 빈번히 나타나는 근육성 동통의 주 원인인 저작근의 과활성으로 유발된 근육의 피로 시에 운동단위전위, 압력통각역치, 근전도 power spectrum의 변화 양상과 이들 척도간의 연관성을 조사하기 위해 시행되었다. 두개하악장애의 병력 및 현증이 없고 정상적인 구치부 교합관계를 가진 평균연령 25.8세인 36명의 정상 성인(남자 26명, 여자 10명)을 대상으로 교근과 전측두근의 지속적인 등길이 수축 전후의 압력통각역치 및 운동단위전위를 측정하였고 인내시간까지의 근수축 동안 근전도 power spectrum을 분석하여 다음과 같은 결론을 얻었다. 1. 지속적인 등길이 수축 후 교근과 전측두근의 압력통각역치는 수축 전에 비해 유의하게 감소하였다. 2. 압력통각역치는 수축 전과 수축 후 모두에서 전측두근이 교근보다 유의하게 높게 나타났으며, 전체적으로 남성이 여성보다 높게 나타나는 양상을 보였으나 성별간의 차이는 전측두근의 수축 후 압력통각역치에서만 통계적으로 유의하게 나타났다. 3. 지속적인 등길이 수축말기의 중간주파수는 수축초기에 비하여 유의하게 감소하였고, 전측두근의 수축초기 중간주파수와 수축말기 중간주파수 모두 교근보다 유의하게 높게 나타났다. 4. 교근은 지속적인 등길이 수축 전에 비하여 수축 후의 운동단위전위의 지속시간,진폭, 면적, 상의 4가지 척도에서 유의한 증가를 보였고 전측두근은 진폭을 제외한 나머지 3가지 척도, 즉 지속시간, 면적, 상의 유의한 증가를 보였다. 5. 교근과 전측두근의 지속적인 등길이 수축 전의 압력통각역치와 운동단위전위 척도 사이에는 통계적으로 유의한 상관관계가 없었고 교근에서는 수축 후의 압력통각역치와 운동단위전위의 지속시간, 진폭, 면적, 상 사이에 유의한 상관관계가 존재하였다. 위의 실험결과를 통해 근육피로 검사에 압력통각역치, 근전도 power spectrum 검사 외에 근육수축의 기능적 최소 단위인 운동단위전위의 분석 또한 유용할 수 있고 추후 만성으로 진행된 근막동통환자와 정상 대조군간의 운동단위 수준에서의 비교연구와 근피로에 더욱 민감한 운동단위전위의 다른 척도에 대한 개발과 연구가 필요하다고 사료된다.

• Sleep Medicine and Psychophysiology
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• v.7 no.2
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• pp.109-114
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• 2000

Objectives: This study was performed to examine the characteristic cardiovascular response patterns associated with the imagination and discussion of anger-provoked events in patients with hwa-byung. Methods: Forty-three female patients with hwa-byung were evaluated with the Korean version of the State-Trait Anger Expression Inventory, the State-Trait Anxiety Inventory, Hamilton Rating Scale for Anxiety, Beck Depression Inventory, and Hamilton Rating Scale for Depression just before the task. Subjective Units of Distress (SUDS) and Vividness of the event (VIVID) during the imagination and discussion of the event were evaluated immediately after tasks. Blood pressure (BP) and heart rate (HR) during baseline, rest, and tasks were also evaluated. Results: Both startle and recovery responses of BP, startle response of HR, SUDS, and VIVID in discussion task were significantly larger than in the imagination task. Conclusion: Results suggest that it is undesirable for the patients to excessively and repeatedly recall and talk about the anger events.

• Korean Journal of Social Welfare
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• v.65 no.4
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• pp.165-193
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• 2013

This study purposes to explore the growing process through spousal bereavement in later life, and to develop the theory. A qualitative research was conducted, and the participants were 17 seniors. The analysis according to Strauss and Corbin's grounded theory(1998), resulted in 143 concepts, 43 subcategories, and 19 categories. Range analysis according to paradigm showed that the causal conditions were 'marital relationships', 'independent/dependent tendencies', and 'emotional readiness for the death of a spouse', and the phenomena were 'depression', 'hopelessness', 'daily stress', 'psychological intimidation', 'regret', and 'sense of being freed'. The contextual conditions that affect these phenomena were 'desire for intimate personal relationships' and 'desire to maintain independence'; the action/interaction strategies to manage the phenomena were 'facing reality' and 'efforts for construction of the new life'; and the mediating conditions that promote or suppress these action/interaction strategies were 'social support' and 'spirituality'. The results were 'reconstruction of the meaning in life', 'increase in self-esteem', 'reinforcement of social network' and 'embrace and acceptance'. Furthermore, when personal growth after bereavement of a spouse was analyzed focusing on changes over time, the growth process consisted of three steps: 'sadness and despair', 'embracing and moving forward', and 'personal growth'. The pattern analyses were performed to typify recurring relations by category, and 5 types were derived. The results of our study show that personal growth after spousal loss is an integrative process in life after crisis, and can be conceptualized as the process of overcoming the despair that immediately follows the death of a spouse, seeking a new life by actively taking control, and discovering a strengthened self.

• Korean Journal of Health Education and Promotion
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• v.28 no.4
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• pp.79-94
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• 2011

Objectives: The aim of this study was to evaluate the effectiveness of smoking cessation clinics for soldiers in the Korean armed forces. In so doing it attempted to identify the predictors of smoking cessation and positive transition of stages of change. Methods: In a single-group pre-post test study design, 5,362 smokers from Korean armed forces participated in the smoking cessation clinic programs based on both the Transtheoretical model and life skills approaches. Changes in stages of change and related variables were measured before the intervention and at 3-month follow-up after the intervention. Results: The cessation rates was 66.0% at 3-month follow-up. With the positive transition to action/maintain stage, proportion of participants in action/maintain stage increased more than 5 times after the intervention. Cons of smoking, self-efficacy, processes of change, and life skills increased, and pros of smoking decreased after the intervention. Predictors of smoking cessation included nicotine dependency, pros of smoking, high levels of self-efficacy, processes of change and life skills. Positive stage transition was predicted by pros of smoking and high self-efficacy. Conclusions: Application of the Transtheoretical model and life skills approaches provided useful strategies for a smoking cessation program in armed forces.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.60-64
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• 2010

Purpose: Until now the general study for breast cancer patient has been mammography, breast sonography for anatomic diagnostics and $^{18}F$-FDG whole body PET for functional one. But the PEM (Positron Emission Mammography) was developed to increase sensitivity, specificity and accuracy to improve the disadvantage of each study. Therefore this present study aims to describe availability of PEM for improving diagnosis of breast cancer. Materials and Methods: During 3 months from January in 2010, PEM was performed on 100 patients who had history of breast cancer. Using Naviscan's PEM Flex Solo II scanner, PEM images of breast were acquired. And then we evaluated sensitivity, specificity and accuracy of PEM data by comparing results of PEM images with postoperative pathologic finding. Results: On the 100 patients, it could reveal 89 true positive, 9 false positive, 7 false negative and 87 true negative. Thus the results of sensitivity, specificity and accuracy for PEM was evaluated 92.7%, 90.6% and 91.7%. Conclusion: The sensitivity, specificity and accuracy have been reported 83.7%, 68.5% and 77.1% in mammography, and that was 89.1%, 79.1% and 83.4% in breast sonography. However the results of PEM were more increased than others. Therefore the results of this study will be available that PEM used diagnosis with breast cancer, used preoperative operation plan and helps to discovery of a part recurrence.

• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.171-179
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• 1997

This study was performed to see whether neurobehavioral tests was affected by the exposure-free time in the workers chronically exposed to organic solvents. Thirty-four female workers were participated and four items among neurobehavioral core test battery of World Health Organization, including digit span, Santa Ana Dexterity, digit symbol and Benton Visual Retention, were administered to the workers. Test was conducted three times-preshift on Monday, preshift on Weekday and during shift on Weekday-per person and the interval of tests was 2 weeks. Digit span forward, Santa Ana Dexterity, digit symbol, and Benton Visual Retention showed significant decrements by performing time, especially during shift on Week-day versus preshift on Monday and preshift on Weekday. In addition, the score at preshift on Weekday was significantly lower than preshift on Monday, in preferred Santa Ana Dexterity and digit symbol. Generally, those who were exposed to high concentration, over 50 years and under 6 years of education showed marked decrease of score at during shift. So, it would be desirable that neurobehavioral test is conducted at preshift on Monday and items related to short term memory could be considerable to be done at preshift on Weekday.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.223-229
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• 2006

Recently canine parvovirus(CPV) enteritis had been controlled successfully by the use of low-passage high titer modified live CPV vaccines. However, outbreaks of CPV enteritis have been continued in Korea. In this study, we carried out epidemiological investigation on the recent outbreaks of CPV enteritis of dogs and determined the potential prognostic factors affecting the survival of dogs. The total of 140 dogs diagnosed for CPV enteritis were statistically analysed. The majority of dogs were from 6 to 18 weeks of age and were not vaccinated or incompletely vaccinated. There were significant difference in the survival rate between male and female dogs with CPV enteritis and among the age groups(p<0.05). Moreover, there was significant difference in the survival rate of dogs between HI titer <80 group and HI titer 160 group(p<0.05). The majority of dogs had a history of diarrhea, vomiting, lethargy and dehydration. It was considered that recent outbreak of CPV enteritis in Korea caused by the failure of vaccination and/or by the inadequate antibody responses to CPV vaccines. Prophylactic measures should include isolation of young dogs from the dog population until the vaccination can be expected to provide protection.