• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.1
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• pp.52-58
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• 2014

Objectives: Using laborers participating in the petrochemical factory turnaround process as subjects, this study aims to identify exposure to benzene in the air and examine the relationship between exposure and the excretion of urinary metabolites by measuring concentrations of urinary trans, trans-muconic acid (t,t-MA). Methods: A passive sampler was used to measure the level of benzene in the air. In order to analyze urinary metabolites, the urine of laborers participating in the turnaround process was collected twice daily, both before and after work. In addition, a survey was conducted on work factors and lifestyle habits as factors affecting the concentration of urinary metabolites. Results: During the survey period, benzene was detected in the samples from all workers, and its average concentration was $0.16{\pm}0.22ppm$. The average concentration of t,t-MA after work was $1.20{\pm}1.86mg/g$ creatinine, and the results of analyzing urinary metabolites concentration before and after work showed statistically significant differences(p=0.003). There was also a statistically significant correlation (r=0.52, p=0.002) between benzene in the air and the concentration of after-work urinary t,t-MA. Conclusions: During the turnaround process, the average benzene concentration in workers was $0.16{\pm}0.22ppm$, which was below the exposure limit. However, their average t,t-MA concentration was $1.20{\pm}1.86mg/g$ creatinine, which exceeded the exposure limit of 1mg/g creatinine. The characteristics of turnaround process work require considerations such as underestimating the passive sampler being used and the skin absorption of benzene, and there needs to be a simultaneous assessment of working environment measurements and biological monitoring.

• Journal of Oral Medicine and Pain
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• v.45 no.1
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• pp.1-11
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• 2020

Purpose: The purpose of this study was to assess influences of psychological factors on sleep disturbances in young adults through the revised version of the Minnesota Multiphasic Personality Inventory (MMPI-2). Methods: Two hundred and ninety nine college students in Gyeonggi-do completed the MMPI-2 and a questionnaire related to sleep disturbances and collected data were analyzed by logistic regression. Results: The odds of tooth grinding increased significantly with the increase of T-score of hysteria (Hy) scale. The increase of T-score of hypomania (Ma) and social introversion (Si) scale significantly contributed to the risk of insomnia. The occurrence of insomnia increased significantly as T-score of somatic complaints (RC1) and psychoticism (PSYC) scale increased. The odds of tooth grinding increased significantly as T-score of anxiety (ANX) and family problems (FAM) scale increased. The occurrence of insomnia decreased significantly with the increase of T-score of type A behavior (TPA) scale. The increase of T-score of dominance (Do) scale significantly contributed to the risk of tooth clenching. The odds of tooth grinding decreased significantly as T-score of MacAndrew alcoholism-revised (MAC-R) scale increased, whereas it increased significantly as T-score of addiction potential scale (APS) increased. No scale of MMPI-2 significantly affected the occurrence of snoring. Conclusions: T-scores of Hy, ANX, FAM, Do, MAC-R, and APS scales on MMPI-2 affected the risk of bruxism. T-scores of Ma, Si, RC1, PSYC, and TPA scales on MMPI-2 influenced the occurrence of insomnia. The psychometric instrument such as MMPI-2 is helpful in understanding and managing bruxism and insomnia.

• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.295-306
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• 2006

In this paper, by using the Krasnoselskii fixed point theorem, we study the existence of 2m or 2m + 1 symmetric positive solutions of fourth-order two point boundary value problem y(4)(t) - f(t, y(t), y"(t))= 0, y(0) = y(1) = y'(0) = y"(1)=0.

• Journal of Oriental Neuropsychiatry
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• v.4 no.1
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• pp.155-164
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• 1993

In this study the author had attempted to establish a correlation among alcohol use and MMPI and lunar cycle. MMPI was carried on 2, April 1992(the last day of the second lunar month) and 15, June 1992(the fifteenth day of the fifth lunar month). These experiments took male and female students who were in WON KWANG University as subjects. The results of it suggested the followings. 1) Drinkers and normal subjects average of T-score in each scales were in a normal scores. 2) In every scales except L,K,Si scales drinkers showed higher scores than normal subjects. There was a significant difference on L, F, Pd, Pa, Sc, Ma scales. 3) On the fifteenth day of the month, drinkers showed Higher T-Scores than normal subjects in every scales excepts L,K,Si scales. There was a significant difference in Ma scale. 4) On the last day of the month, drinkers showed higher T-scores than normal subjects in every scales except L,K,Mf,Si scales. There was a significant difference on L, F, Pd, Sc, Ma scales. 5) Drinkers showed higher than normal subjects in symptom of neurosis and psychosis. As the results of above, human character changes to some extend according to alcohol use. There is a tendency that repeated drinking of college students prone to change into habitual drinking or alcoholic impairment. So controlled drinking among the college students is highly recommended.

• Journal of East-West Nursing Research
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• v.2 no.1
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• pp.62-82
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• 1997

If we eat long time foods that don't suit our constitution, health is broken and we take a disease. Therefore, care of foods and taking medicine by constitutional notion have a object that is normal control of constitution. It is attained when we maintain an adequate balance of Jang and Bu(臟腑) organs functional deflection. Theory of SaSang constitution by Lee-Jae Ma provides us a proper base of theory. But, later foods and drugs classified by constitution, that is suggestied by many scholars, is some different. Therefore, it is doubtful whether choice of foods and drugs suitable to constitution is right. If we use foods and drugs suitable to constitution exactly, we can decrease a side effect arisen from unsuitableness. On this, I study by literatures in order to provide foundational data. Lee-Jae Ma classified four species constitution, I compared twelve literatures by constitution, classified profit and harmful foods, and arranged and classify drugs that literature writer suggests in common. On base of this study, I suggest that foods and drugs classified by constitution is as follows. 1. Lee-Jae Ma made SaSang constitution medicine, but didn't suggestied use of foods, therefore, commoness of foods constitutional classification must be arranged. 2. Also commoness of drugs constitutional classification must be arranged. 3. Other literatures must be compared and analyzed except those of this study, because I didn't analyze many SaSang literatures.

• Structural Engineering and Mechanics
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• v.19 no.3
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• pp.261-279
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• 2005

The hot spot stress approach is usually adopted in the fatigue design and analysis of tubular welded joints. To apply the hot spot stress approach for fatigue evaluation of long span suspension bridges, the FEM is used to determine the hot spot stress of critical fatigue location. Using the local finite element models of the Tsing Ma Bridge, typical joints are developed and the stress concentration factors are determined. As a case for study, the calculated stress concentration factor is combined with the nominal representative stress block cycle to obtain the representative hot spot stress range cycle block under traffic loading from online health monitoring system. A comparison is made between the nominal stress approach and the hot spot stress approach for fatigue life evaluation of the Tsing Ma Bridge. The comparison result shows that the nominal stress approach cannot consider the most critical stress of the fatigue damage location and the hot spot stress approach is more appropriate for fatigue evaluation.

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.191-206
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• 2011

The emplacement ages, whole-rock geochemistry and Sr-Nd isotopic compositions of granitoid rocks from Cheongju area, South Korea, were investigated for delineating their petrogenetic link to the Jurassic Daebo granitoid rocks. Zircon crystals were collected from the diorite, biotite granite and acidic dyke samples in a single outcrop. Cross-cutting relationships show that the emplacement of diorite was postdated by the intrusion of biotite granite. Both rocks have been subsequently intruded by acidic dyke. The U-Pb isotopic compositions of zircon from the diorite, biotite granite, and acidic dyke were measured using a SHRIMP-II ion microprobe, yielding the crystallization ages of $174{\pm}2Ma$, $170{\pm}2Ma$, and $170{\pm}5Ma$, respectively, with 95% confidence limits ($t{\sigma}$). The emplacement ages are consistent with those determined from the above relative ages. The major and trace element patterns of the rocks are consistent with those of the Jurassic Daebo granitoid rocks, possibly suggesting a subduction-related I-type granite. The geochemical signature is, however, betrayed by the Sr and Nd isotopic compositions of these rocks. The isotopic signatures suggest that the rocks were produced either by the partial melting of lower-crust or by the mantle-derived magma contaminated by the basement rocks during its ascent and/or emplacement. In addition, the inherited ages of zircons of the rocks (ca. 2.1, 1.8, 0.8 and 0.4 Ga) suggest a possible assimilation with crustal rocks from the Gyeonggi massif and Ogcheon metamorphic belt.

• Journal of dental hygiene science
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• v.8 no.3
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• pp.109-115
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• 2008

Two t-amines, N,N-dimethylaniline (MA), N,N-dimethyl-p-toluidine (MPT), were investigated as new visible light amine initiators for a dental resin composite of UDMA in order to improve photopolymerization effect. Three t-amines mixed with three photosensitizers, camphorquinone(CQ), 1-phenyl-1,2-propane dione(PD) and diacetyl (DA), respectively. And then this mixtures are added to resin monomer, UDMA. Photopolymerization efficiency of UDMA was studied through the use of FT-IR absorption spectroscopy. The photopolymerization effect of amine initiators were compared with that of 4-(dimethylamino)ethyl methacrylate (AEM), the most widely used photoinitiator. The photopolymerization efficiency of UDMA containing the amine initiator increased with irradiation time. The relative polymerization efficiency containing the CQ photosensitizer increase was in the order: AEM < MPT < MA. And the relative polymerization efficiency containing the PD photosensitizer increase was in the order: MPT < AEM < MA. This result shows that MA is most efficient amine initiator with CQ and PD.

• Child Health Nursing Research
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• v.15 no.4
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• pp.335-342
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• 2009

Purpose: This study, using a pre-post test design of non-equivalence comparative group, was done to determine effects of Kangaroo care (KC) on growth in premature infants and on maternal attachment (MA). Methods: Fifty-three premature infants were assigned to the KC (24) or control group (CG) (29). Data were collected from July 2007 to June 2008. KC was given for 60 min at a time, Monday, Wednesday, and Friday for 10 times. Weight, height, and head circumference (HC) of premature infants were checked before the program started. Following the initial measurement, the program was given and measurements were taken again at the end of the program. For measurement of attachment between mother and infant, data collection was done using structured self-reported questionnaires. Results: KC group had a higher weight (t=2.565, p=.013), height (t=2.182, p=.034) and HC (t=2.468, p=.017) than the CG. Compared to the CG, the KC had significantly higher scores in MA (t=2.026, p=.048). Conclusion: The results of this study suggest that the practice of KC in the nursing environment might actively promote attachment between mother and infant as well as acceleration of growth for premature infants as one of the most efficient nursing intervention.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1019-1021
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• 1992

This paper deals with the stress of the converters using the resonant switches. It is represented the reduction of the voltage and current stresses. According to the configuration of the multiple poly-phase converter. Especially, about buck ZVS-QRC it is studied the reduction of the voltage stress, and represented the result of simulation.