• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.255-261
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• 2016

The purpose of this study was to investigate the relationship between excessive daytime sleepiness (EDS) and blood pressure (BP) in patients with obstructive sleep apnea-hypopnea (OSAH). Patients were classified into four groups based on their severity of polysomnographic data: the snoring group (n=108)-characterized by Apnea-Hypopnea Index (AHI<5); the mild OSA group (n=186)-AHI $5{\leq}AHI$<15; the moderate OSA group (n=179)- AHI $15{\leq}AHI$<30; and the severe OSA group (n=233)-$AHI{\geq}30$. On the same night of polysomnography (PSG), BP levels were measured before sleeping (bedtime BP) and immediately after waking up on the following morning (morning BP). EDS was recognized as ESS (epworth sleepiness scale)${\geq}9$. The differences and correlations between BP and PSG parameters in the EDS and non-EDS groups of OSAH patients were analyzed. MAP was positively correlated with BMI, AHI, and total arousal (r=0.099, r=0.142, r=0.135, p<0.01, p<0.01, p<0.01), while negatively correlated with mean $SaO_2$ (r=-0.258, p<0.01). The EDS group had overall younger population ($47.2{\pm}11.3$ vs $50.3{\pm}11.4$, p=0.023), higher DBP (both bedtime and morning, $83.1{\pm}9.7$ vs $81.4{\pm}8.8$ and $86.4{\pm}9.2$ vs $83.6{\pm}9.7$)(p=0.031, p=0.047), and higher SBP (both bedtime and morning, $126.7{\pm}11.2$ vs $123.4{\pm}12.4$, $128.9{\pm}12.4$ vs $125.3{\pm}12.9$)(p=0.021, p=0.021) than compared with the non-EDS group. In hypertensive OSAH patients, patients with EDS were also younger and had higher total arousal number, as well as higher morning and bedtime DBP and SBP than compared with the non-EDS group (p<0.005, p=0.008, p<0.001 and p<0.001). EDS in OSAHS patients is a special phenotype characterized by younger age, higher DBP, more severe desaturation, and hypertension.

• Korean Journal of Psychosomatic Medicine
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• v.10 no.1
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• pp.37-47
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• 2002

Objective : Previous studies have suggested an association between sleep-related breathing disorder (SRBD) and several psychological problems, and there were increasing recognition of the link. The purpose of this study is to evaluate the characteristic profiles of MMPI and SCL-90-R in patients with SRBD. Methods : This study consisted of 80 SRBD patients(73 men, 7 women) referred from Sleep Disorder Clinic of Dong-A University Hospital, Busan, Korea. Basic informations including demographic findings and physical examination were collected. Subjects completed the Epworth Sleepiness Scale(ESS), Minnesota Multiphasic Personality Inventory(MMPI), and Symptom Check List-90-Revision (SCL-90-R) prior to standard overnight polysomnography that was performed at hospital sleep laboratory. SRBD was divided into two groups of primary snoring(PS) and obstructive sleep apnea(OSA) according to polysomnographic findings. Results : SRBD showed significant elevation rate of Hs, D, and Hy scales of MMPI and SOM scale of SCL-90-R, which exceeded the rate expected in normal individuals(>5%, 2SD). On comparison of clinical scales of SCL-90-R, OSA group had significantly greater mean score than that of PS group in terms of O-C, DEP, PAR, GSI(p<0.05), SOM and PST(p<0.01). OSA group also showed significantly higher elevation rate in Hs scale of MMPI and SOM scale of SCL-90-R than that of PS. Among OSA group, three scales of MMPI(D, Pt, Si) and three scales of SCL-90-R(ANX, PAR, PSDI) had significant correlation with some PSG variables including total sleep time and sleep efficiency. Among PS group, two scales of MMPI(Hy and Pt), elevation rate of MMPI scales and three scales of SCL-90-R(I-S, PAR, PSDI) had significant correlation with some PSG variables including sleep efficiency, sleep latency and REM sleep percent. Conclusion : The above results suggest that SRBD show neurotic profiles in MMPI and SCL-90-R. This study also clearly indicates that PS group are suffered from clinically meaningful psychiatric symptoms, which are quantitatively lessened but qualitatively similar as compared to that of OSA group.

• Progress in Medical Physics
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• v.20 no.1
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• pp.37-42
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• 2009

Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.

• Sleep Medicine and Psychophysiology
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• v.23 no.1
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• pp.16-24
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• 2016

Background and Objectives: Obstructive sleep apnea (OSA) is often undiagnosed but is an important risk factor affecting the health of an individual. The level of awareness of the illness among patients with OSA is low and is not correlated with severity of the illness. This study was conducted to compare awareness of OSA symptoms and illness between patients with OSA and simple snorers. Materials and Methods: Two hundred eighty-two patients who were suspected of having OSA participated in this study. All subjects underwent overnight polysomnography. Those with an apnea-hypopnea index (AHI) ${\geq}5$ were classified as the OSA group, while those with an AHI < 5 were classified as the simple snoring group. A sleep questionnaire, which included items on awareness of the illness, OSA, and sleep symptoms, was administered to all subjects and their bed-partners. Results: Simple snorers were much more aware of their symptoms such as snoring, irregular breathing, and apnea than were patients with OSA. Bed-partners of simple snorers were also more aware of the participants' sleep symptoms than were partners of patients with OSA. However, the duration of OSA symptoms was longer in the OSA group. In the correlation analysis, the level of awareness of OSA symptoms was negatively correlated with AHI, age, body mass index, and Epworth Sleepiness Scale score. Among the sleep questionnaire and polysomnography results, only Pittsburgh Sleep Quality Index was positively correlated with level of awareness of OSA symptoms. The minority of the respondents had heard about the treatment methods of continuous positive airway pressure and oral appliance and preferred them as treatment options. Conclusion: This study suggests that simple snorers are more aware of their symptoms than are patients with OSA. A higher severity of OSA, represented by a higher AHI, is correlated with lower awareness of one's OSA symptoms.

• Sleep Medicine and Psychophysiology
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• v.9 no.2
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• pp.106-114
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• 2002

Objectives: Daytime sleepiness is a common symptom and is associated with sleep behavior, sleep deprivation, and night shift, etc. It is also one of the most important symptoms of sleep disorders like obstructive sleep apnea (OSA). According to our survey on Korean literature, a few studies have dealt with daytime sleepiness, and we have not been able to locate any study comparing normal subjects with polysomnography-proven sleep disorder patients regarding daytime sleepiness. We aimed at comparing daytime sleepiness among normal healthy daytime workers, medical students being expected to have daytime sleepiness due to chronic sleep deprivation, and patients having sleep disorders diagnosed with polysomnography. We also studied the association between subjective daytime sleepiness and objective polysomnographic findings in patients with sleep disorders. Methods: One hundred three hospital workers, 137 medical students, and patients with sleep disorders were studied. Sleep disorders included OSA, periodic limb movements in sleep (PLMS), insomnia, and narcolepsy. The degree of subjective sleepiness in each group was measured by the Korean version of Epworth sleepiness scale and compared. The relationship between polysomnographic findings reflecting severity of sleep disorder in each patient group and subjective sleepiness was analyzed. As for patients with narcolepsy, the relationship between the mean sleep latency and subjective sleepiness was studied. Results: There was a significant difference of ESS score (F=68.190, dF=5.752, p<0.001) among daytime workers, medical students, and sleep disorder patients. In OSA patient group, the degree of the sleepiness had no significant correlation either with mean O2 satuaration (p=0.062) or with RDI (p=0.807). In PLMS patient group, there was no correlation between periodic limb movement index (PLMI) and subjective sleepiness (p=0.761). In narcolepsy patient group, the subjective sleepiness had no correlation with mean sleep latency measured with MSLT (p=0.055). Conclusion: We found a significant difference of subjective sleepiness among daytime workers, medical students, and patients with sleep disorders. However, no consistent correlation was found between severity of subjective sleepiness and objective polysomnographic findings reflecting severity of each sleep disorder. This research confirms that the evaluation of subjective sleepiness is important clinically, but it cannot substitute the objective measures such as nocturnal polysomnography and MSLT.

• Korean Journal of Clinical Laboratory Science
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• v.44 no.2
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• pp.52-58
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• 2012

Patients with obstructive sleep apnea (OSA) often have more aggravated symptoms in the supine position. We tried to investigate the clinical characteristics and the predictive factors for positional OSA. Polysomnographic data were reviewed for OSA patients (apnea hypopnea index, $AHI{\geq}5$) from April, 2008 to April, 2011 at the Asan Medical Center. Clinical data, comorbid medical condition data and questionnaires (SF-36, MFI-20, ESS, BDI, STAI) were assessed. All patients were classified into two groups: positional patients (PP) group and non-positional patients (NPP) group. PP was defined as a patient who had the AHI in the supine position was at least twice as high as that in the lateral position. The body position of patients was confirmed by sleep position sensor and video monitor. All patients had at least 30 minutes of positional and 30 minutes of non-positional sleep. We compared clinical, medical, polysomnographic data, and questionnaire results between two (PP and NPP) groups and investigated predictive factors for the PP group using binary logistic regression analysis. In total, 371 patients were investigated. 265 (71.4%) was categorized as PP group and 106 (28.5%) as NPP group. The mean age ($mean{\pm}SD$) was higher in the PP group ($52.4{\pm}9.8$) than in the NPP group ($49.5{\pm}11.9$) (p<0.05). Comparison of sleep parameters between the PP and the NPP group showed that the PP group had significantly lower BMI (PP: $26.1{\pm}3.2kg/m^2$; NPP: $27.8{\pm}4.3kg/m^2$, p<0.001), neck circumference (PP: $39.7{\pm}2.8cm$; NPP: $41.5{\pm}3.7cm$, p<0.001) and hypertension rate (PP: n=89/265 (33.5%); NPP: n=48/106 (45.2%), p=0.0240). In the PP group, the percentage of deep sleep (PP: $8.7{\pm}8.1%$; NPP: $5.6{\pm}7.0%$, P=0.001) and rapid eye movement (REM) (PP: $17.5{\pm}6.1%$; NPP: $14.0{\pm}6.9%$, p<0.001) were significantly higher whereas the percentage of light sleep (stage N1) was significantly lower than the NPP group (PP: $30.4{\pm}12.3$; NPP: $44.5{\pm}20.8%$, p<0.001). During the sleep, the AHI in the supine position (PP: $48.6{\pm}19.5$; NPP: $60.5{\pm}22.6$, p<0.001) and in the non-supine position (PP: $9.4{\pm}8.9$; NPP: $48.4{\pm}24.8$, p=<0.001) were significantly lower and the minimal arterial oxygen saturation in non-REM sleep was significantly higher in the PP group (PP: $80.3{\pm}7.6$; NPP: $75.1{\pm}9.9$, p=<0.001). There were no significant differences in all questionnaires including quality of life. The results of the binary logistic regression analysis showed that age, the amount of REM sleep(%) and AHI were significant predictive factors for positional OSA. The significant predictive factors for positional OSA were older age, higher percentage of REM and lower AHI. The questionnaire results were not significantly different between the two groups.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.209-213
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• 2019

Recently, demand for high energy density and long cycling stability of energy storage system has increased for application using with frequency regulation (F/R) in power grid. Supercapacitor have long lifetime and high charge and discharge rate, it is very adaptable to apply a frequency regulation in power grid. Supercapacitor can complement batteries to reduce the size and installation of batteries. Because their utilization in a system can potentially eliminate the need for short-term frequent replacement as required by batteries, hence, saving the resources invested in the upkeep of the whole system or extension of lifecycle of batteries in the long run of power grid. However, low energy density in supercapacitor is critical weakness to utilization for huge energy storage system of power grid. So, it is still far from being able to replace batteries and struggle in meeting the demand for a high energy density. But, today, LIC (Lithium Ion Capacitor) considered as an attractive structure to improve energy density much more than EDLC (Electric double layer capacitor) because LIC has high voltage range up to 3.8 V. But, many aspects of the electrochemical performance of LIC still need to be examined closely in order to apply for commercial use. In this study, in order to improve the capacitance of LIC related with energy density, we designed new method of pre-doping in anode electrode. The electrode in cathode were fabricated in dry room which has a relative humidity under 0.1% and constant electrode thickness over $100{\mu}m$ was manufactured for stable mechanical strength and anode doping. To minimize of contact resistance, fabricated electrode was conducted hot compression process from room temperature to $65^{\circ}C$. We designed various pre-doping method for LIC structure and analyzing the doping mechanism issues. Finally, we suggest new pre-doping method to improve the capacitance and electrochemical stability for LIC.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.871-877
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• 2018

Storing the surplus energy from renewable energy resource is one of the challenges related to intermittent and fluctuating nature of renewable energy electricity production. $CO_2$ methanation is well known reaction that as a renewable energy storage system. $CO_2$ methanation requires a catalyst to be active at relatively low temperatures ($250-500^{\circ}C$) and selectivity towards methane. In this study, the catalytic performance test was conducted using a pressurized bubbling fluidized bed reactor (Diameter: 0.025 m and Height: 0.35 m) with $Ni/{\gamma}-Al_2O_3$ (Ni70%, and ${\gamma}-Al_2O_3$30%) catalyst. The range of the reaction conditions were $H_2/CO_2$ mole ratio range of 4.0-6.0, temperature of $300-420^{\circ}C$, pressure of 1-9 bar, and gas velocity ($U_0/U_{mf}$) of 1-5. As the $H_2/CO_2$ mole ratio, temperature and pressure increased, $CO_2$ conversion increases at the experimental temperature range. However, $CO_2$ conversion decreases with increasing gas velocity due to poor mixing characteristics in the fluidized bed. The maximum $CO_2$ conversion of 99.6% was obtained with the operating condition as follows; $H_2/CO_2$ ratio of 5, temperature of $400^{\circ}C$, pressure of 9 bar, and $U_0/U_{mf}$ of 1.4-3.

• Journal of the Korean Society of School Health
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• v.9 no.1
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• pp.77-98
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• 1996

This studies designed to work out a theoretical framework on the experience of sexual abuse from the perspective of grounded theory in an effort to provide more practical and efficient nursing intervention for female victims. The subcategories identified were "sexual abuse", "threatening", "absent mindness", "embarrassment", "horripilation", "dizziness", "wondrousness", "filthiness", "sexual curiosity", "violence level", "victim's age", "neighbors response", "victims personality", "common experience", "sexual abuse information", "family relations", "level of familiarity", "hiding", "suppression", "self-torture", "self-protection", "avoidance", "asking aid", "withdrawal", "hatred", "confusion", "dodging, "remmant", and "pursuing". The 29 subcategories given above were further integrated into 16 categories such as "victimizedness", "being astounded", "filthiness", "degree", "developmental stage", "response pattern", "personality", "rarity", "information availability", "family support", "cover-up", "escaping", "informing", "negative internalization", and "positive pursuit of change". The core categories linked to all the other categories turned out to be "being taken aback" and "filthiness" incorporating the relevant subcategories. A total of 23 theoretical hypothesis emerged in the process of analyzing data. 1. the grater sexual curiosity, the weaker the senses of being taken aback and filthiness. 2. The weaker sexual curiosity, the stronger the senses of being taken aback and filthiness. 3. The stronger the level of violence, The more violent the senses of being taken aback and filthiness. 4. The lower the level of violence, the weaker the senses of being taken aback and filthiness. 5. The younger the victims, the stronger the senses of being taken aback and filthiness. 6. The older the victims, The weaker the senses of being taken aback and filthiness. 7. 'Escaping' will transpire regardless of the given circumstances. 8. The weaker the senses of being taken aback and filthiness, the more probable 'informing' and 'escaping' transpire. 9. The stronger the senses of being taken aback and filthiness, the more probable 'informing' and 'escaping' transpire. 10. The more protective the response from 'informing' and 'escaping' transpire around, the more likely the response to being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 11. The more repelling the response from around, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 12. The more open minded the personality of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 13. The more closed the personality of tile subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 14. The more frequent the experience of sexual abuse, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 15. The less frequent the experience of sexual abuse, the more lilely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 16. The more available information concerning sexual abuses, the more likely response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping. 17. The less available information concerning sexual abuses, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 18. The more cohesive the family of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 19. The less cohesive the family of the subject, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping'. 20. The less familiar the subject is with the abuser, the more likely the response to 'being taken aback' and 'filthiness' will be 'informing' and 'escaping'. 21. The less familiar the subject is with the abuser, the more likely the response to 'being taken aback' and 'filthiness' will be 'covering-up' and 'escaping. 22. The more likely the response to 'being taken aback' and 'filthiness' is 'informing and 'escaping', the more positive changes the subject will pursue. 23. The more likely the response to 'being taken aback' and 'filthiness' is 'covering-up' and 'escaping', the more negative changes the subject will pursue. The following four hypotheses were conformed in the process of data analysis. 1) In case the level of violence is strong but 'being taken aback' and 'filthiness' in weak because of strong sexual curiosity and also if information concerning sexual abuse is not readily available and the frequency is low, negative internationalization marked by 'covering-up' and 'escaping' will take place despite the fact the subject is open-minded, the family is cohesive and the abuser is unfamiliar. 2) In case the level of violence is weak but 'being taken aback' and 'filthiness' is weak combined with weak sexual curiosity and also if information concerning sexual abuse is readily available and the response from around is protective and the frequency is high, the subject will pursue positive changes to 'being taken aback' and 'filthiness', further aided by the fact that the subject is open-minded, the family is cohesive and the abuser is unfamiliar. 3) In case the level of violence is strong and 'being taken abuse' and 'filthiness' is strong because of weak sexual curiosity and also if information concerning sexual abuse is reading available and the response from around is readily available and the response from around is protective and the frequency is low, the subject will persue positive changes marked by 'informing' and 'escaping' despite the fact that the family cohesion is weak and the abuser is familiar. 4) In case the level of violence is strong and 'being taken aback' and 'filthiness' is strong because of weak sexual curiosity and also if information concerning sexual abuse is not readily available and the response from around is respelling and the frequency is low negative internalization like 'covering-up' and 'escaping' will take place, further aggravated by the fact that the subject's personality is closed, family cohesion is weak, and subject is familiar. On the basis of the above finding, it is recommended that nursing intervention should focus on promoting the milieu conductive to the victims pursuing positive changes along with the adequate aids from protection facilities as well as from the people around them.

• (The)Study of the Eastern Classic
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• no.70
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• pp.435-466
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• 2018

"Hajaeilgi (荷齋日記)" was written by Ji Gyu-sik, a gongin of Saongwon (司饔院)'s branch, almost everyday for 20 years and 7 months from January 1st, 1891 until the leap month of June 29th, 1911. It deals with many different areas including domestic and foreign circumstances, custom, rituals, all the affairs related to the branch, and also everyday life. Particularly, Ji Gyu-sik did not belong to the yangban class, and we can hardly find diaries written by such class' people. Here, what this author pays attention to among the things written in "Hajaeilgi" is the contents about rituals, especially coming of age, wedding, funeral and ancestral rites. Ji Gyu-sik did write in his "Hajaeilgi" about coming of age, wedding, funeral and ancestral rites that were actually performed then as a person not belonging to the yangban class. Such diaries are very rare, and its value is highly appreciated as a material. Particularly, from the late 19th to the early 20th century of this author focuses on the a study of coming of age, wedding, funeral and ancestral rites as we can see some aspects about it from his diary. Coming-of-age rites were carried out in the first month of the year generally, and in this period, we can see the transformation of their performing period as it was diversified then. This was not exceptional in yangban families. About wedding, while it was discussed, it came to be canceled more often than before maybe because they were going through the process of enlightenment then. It seems that choosing the day was not done in the bride's family always. Jungin or commoners had a weeding in the bride's house, but when it was needed, it was also performed in the groom's house. Ji Gyu-sik followed the traditional wedding procedure for his children rather faithfully, but it was applied flexibly according to the two families' situations or conditions. Ignoring the traditional manners, they had a wedding in the period of mourning or performed a wedding in the groom's house bringing the bride there. It seems that this was related to the decline of Confucian order in the society in the process of modernization. Also, the form of donations changed, too. Gradually, it was altered to the form of money gifts. Moreover, unlike before, divorcing seems to have been allowed then. Remarriage or divorce was the custom transformed from before. Funeral rites had different durations from death up to balin (carrying out a bier for burial) and hagwan (lowering a coffin into the grave), and so it means that they also went through transformation. Sa-daebu used usually 3 months but here was 7 days from death to balin normally, but it seems that there were yangban families not following it. The traces of 3-iljang (burial on the third day after death) most commonly found these days and chowoo jaewoo samwooje can be also found in "Hajaeilgi". Such materials are, in fact, very highly evaluated nowadays. Meanwhile, donations also changed gradually to the form of money. Regarding ancestral rites, time for memorial service was not fixed. Ji Gyu-sik did not follow jaegye (齋戒) before carrying out gijesa, and in some worse case, he went to pub the day before the memorial service to meet his lover or drink. This is somewhat different from the practice of yangban sadaebu then. Even after entering Christianity, Ji Gyu-sik performed memorial service, and after joining Cheondogyo, he did it, too. Meanwhile, there were some exceptions, but in Hansik or Chuseok, Ji Gyu-sik performed charye (myoje) before the tomb in person or sent his little brother or son to do it. But we cannot find the contents that tell us Ji Gyu-sik carried out myoje in October. Ji Gyu-sik performed saengiljesa calling it saengsincharye almost every year for his late father. But it is noticeable that he performed saengsincharye and memorial service separately, too, occasionally. The gijesa, charye, myoje, and saengsincharye carried out by jungin family from Gyeonggi Gwangju around the time that the status system was abolished and the Japanese Empire took power may have been rather different and less strict than yangban family's practice of ancestral rites; however, it is significant that we can see with it the aspects of ancestral rites performed in family not yangban. As described above, the contents about the a study of coming of age, wedding, funeral and ancestral rites found in "Hajaeilgi" are equipped with great value as material and meaningful in the perspective of forklore.