• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.547-561
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• 1998

Obstructive sleep apnea (OSA) is a disorder characterized by repetitive episode of upper airway collapse during sleep. Recent studies showed that not only the anatomic factors but the physiologic factors of the upper airway also have effcts on the occurrence of apnea and that the genioglossus muscle also plays an important role in the maintenance of the upper airway. A variety of therapies were performed to treat OSA, and among them the use of mandibular repositioning appliances showed reasonable results. But there is still a lack of research on the structural and physiological mechanism upon the use of mandibular repositioning appliances. The author selected 26(male 17, female 9) OSA patients that came to the Yonsei University Dental Hospital, Department of Orthodontics, and 20 normal adults (male 10, female 10) and took cephalometric radiographs of them in a supine position before and after the placement of the mandibular repositioning appliance to see the structural changes of the upper airway and compare the therapeutic effects between the two groups. We also studied the waking genioglossus muscle activity in OSA patients and investigated the difference in the electromyogram of the genioglosssus muscle upon the change in body posture and the use of mandibular repositioning appliance. Following results were obtained. 1. Among the cephalometric measurements of the upper airway structure, the length of the soft palate, maximum thickness of the soft Palate and SPAS, MAS, VAL, H-H1, MP-H showed statistically significant differences between the normal and OSA groups, but the IAS and EAS showed no statistically significant differences between the two groups. 2. In both the normal and OSA groups, as the epiglottis moved forward on wearing the mandibular repositioning appliance, the epiglottis level of the upper airway increased and the maximum thickness of the soft palate changed and the hyoid bone also moved forward, but the IAS in both groups showed various results and the effect of the mandibular repositioning appliance on the structure of the upper airway was different in the two groups. 3. Upon changing the position, the electromyogram of the genioglossus muscle showed a increasing tendency but there was no statistically significant differences, and when the mandibular repositioning appliance were worn there was a statistically significant increase in the electromyogram of the genioglossus muscle in both the upright and supine positions. The mandibular repositioning appliances not only have an effect on the anatomical structure of the upper airway but also on the physiology of the upper airway. There are different responses to the use of mandibular repositioning appliance between the normal and OSA groups therefore it could be considered to have the different physiology of the upper airway between the two groups.

• Sleep Medicine and Psychophysiology
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• v.8 no.1
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• pp.22-29
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• 2001

Objectives: Obstructive sleep apnea syndrome (OSA) is a moderately prevalent disorder. Even though much progress has been made in the diagnosis of this disorder, the cost-effectiveness of nocturnal polysomnography is undertermined and physicians and patients are still hesitant to undergo this procedure. The authors wanted to see the validity of chin press/tongue curl maneuver in estimating the severity of OSA which is easy to measure and was originally proposed by Simmons etc. by looking at the correlations between this score and the conventional respiratory disturbance indices. Methods: Forty-three sleep-related breathing disorder patients (28 OSA patients and 15 upper airway resistance syndrome (UARS) patients) who underwent investigation for posssible OSA were studied. Two conventional indices of OSA (apnea/hypopnea index (AHI) and oxygen saturation dip rate (SaO2 dips)), four other sleep variables (lowest SaO2, % of time with SaO2<90% (%SaO2 <90), % of sleep stage 1, mean length of SaO2 dips) and the score of Epworth sleepiness scale (ESS) were compared with the chin press score (CPS) which was newly revised by the author and ranges from 0 to 6. Results: The age of subjects was $45.95{\pm}12.47$ (range 14-76) and their average BMI was $25.98{\pm}3.61$ (range 19.65-37.64). There were no significant differences in age, sex and BMI except repiratory disturbance indices and ESS (p<0.05) between OSA and UARS group. Grouped median CPS of the all subjects was 4.14 (range 1-6). There was a remarkable relationship between CPS and diagnosis category (Likelihood Ratio $X^2$ test; $X^2$=17.41, df=5, p=0.004) and measures of association (Somers' $d=0.65{\pm}0.12$, t=4.83, p=0.000) indicated that CPS increased when the diagnosis changed from UARS to OSA. Spearman's rank correlations between CPS and SaO2 dips (R=0.83), between CPS and AHI (R=0.77) were good (p<0.001). Other variables except mean length of SaO2 dips showed good correlations with CPS as well (p<0.05). Regression analysis indicated that when CPS is 3 there is a provability of 0.35 to have AHI of less than 5. Conclusion: Chin press scores that can be measured easily is well correlation with the conventional sleep apnea indices. They may therefore provide a useful guide in diagnosing obstructive sleep apnea synrome.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.114-127
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• 2018

This study aimed to investigate the levels of Obstructive Sleep Apnea (OSA), health behavior and sleep quality and to examine the predictors of OSA in patients with ischemic cardio-cerebrovascular disease. 141 patients who were admitted to the vascular unit were recruited and surveyed using structured questionnaires. Saturation of Peripheral Oxygen (SpO2) was measured at three time points using a pulse oximeter. Data were analyzed using SPSS/WIN 20.0. The mean age of the subjects was $64.4{\pm}11.1$ years and 61% was men. The 21.3%(n=30) of the subjects were classified as high-risk for OSA by the cut point and 71.6%(n=101) had low sleep quality. OSA high-risk group showed significant difference in SpO2 in the middle of sleep (p=.006) and at the end of sleep (p=.004) compared to the low-risk group. Multiple logistic regression analysis showed that perceived frequent snoring, smoking, obesity, lack of exercise among health behavior were found as predicting factors on OSA. OSA or persistent snoring should be recognized as a cardiovascular risk factor in the cardiovascular nursing practice. In addition to early treatment of OSA, education and counseling should be provided to patients and their family for prevention of secondary recurrence.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.521-528
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• 2012

In this study, we analyzed the physical properties of an ethylene oxide adducted amphoteric surfactant such as critical micelle concentration, surface tension, interfacial tension, contact angle, viscosity and phase behavior. The dual function characteristics of an amphoteric surfactant were investigated by determining an isoelectric point, which were attained using zeta potential measurements and quartz crystal microbalance (QCM) experiments. The isoelectric points of DE3-OSA82-AO, DE5-OSA82-AO and DE9-OSA82-AO surfactant systems determined by zeta potential measurements were 6.97, 6.93 and 7.10 respectively and they are in good agreement with the isoelectric point values measured by QCM experiments. The frictional property measured using an automated mildness tester showed that the DE-OSA82-AO surfactant could provide a good softening effect at neutral condition.

• Korean Journal of Health Psychology
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• v.16 no.3
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• pp.557-575
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• 2011

This study tried to examine the characteristics of attention deficits in patients with Obstructive Sleep Apenea(OSA) with different age levels, and to examine which indices of polysomnograms might be related to the indices of attention deficits in OSAs. Two age-level groups and a normal control group were subjected to two computerized attention tests, including a continuous performance test(CPT) and a change blindness task(CBT). In addition, the three groups were subjected to a Polysomnography to extract several sub-indicators of polysomnogram, and an Epworth Sleepiness Scale which measures subjective sleepiness. As results, the OSAs showed significantly more omission and commission errors in CPT, and they showed lower accuracy in CBT compared to the normal group. The results of a correlational analysis showed that attention deficits in OSA are significantly correlated with arterial oxygen saturation among sub-indicators of polysomnograms. In conclusion, OSAs seems to be less attentive, having difficulties in response inhibition, and having deficiencies in noticing important environmental changes. Age seems to make these deficiencies even worse. Especially, the relationship between attention deficiency and hypoxia which could cause irreversible cerebrum damage has an implication in cognitive impairment prevention through early treatment.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.134-147
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• 2009

Tracking and exploiting instantaneous spectrum opportunities are fundamental challenges in opportunistic spectrum access (OSA) in presence of the bursty traffic of primary users and the limited spectrum sensing capability of secondary users. In order to take advantage of the history of spectrum sensing and access decisions, a sequential decision framework is widely used to design optimal policies. However, many existing schemes, based on a partially observed Markov decision process (POMDP) framework, reveal that optimal policies are non-stationary in nature which renders them difficult to calculate and implement. Therefore, this work pursues stationary OSA policies, which are thereby efficient yet low-complexity, while still incorporating many practical factors, such as spectrum sensing errors and a priori unknown statistical spectrum knowledge. First, with an approximation on channel evolution, OSA is formulated in a multi-armed bandit (MAB) framework. As a result, the optimal policy is specified by the wellknown Gittins index rule, where the channel with the largest Gittins index is always selected. Then, closed-form formulas are derived for the Gittins indices with tunable approximation, and the design of a reinforcement learning algorithm is presented for calculating the Gittins indices, depending on whether the Markovian channel parameters are available a priori or not. Finally, the superiority of the scheme is presented via extensive experiments compared to other existing schemes in terms of the quality of policies and optimality.

• Sleep Medicine and Psychophysiology
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• v.16 no.2
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• pp.61-64
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• 2009

Obstructive sleep apnea (OSA) has been definitively shown to be a risk factor for the development of cardiovascular disease and mortality. Recent reports have indicated that obstructive sleep apnea is associated with insulin resistance and impaired glucose metabolism, also have type 2 diabetes. The potential mechanisms leading to the development of type 2 diabetes in OSA patients are likely to be various. Reduced physical activity resulting from daytime somnolence, sympathetic nervous system activation, intermittent hypoxia, sleep fragmentation and sleep loss, dysregulation of the hypothalamic-pituitary axis, alteration in adipokine profiles, and activation of inflammatory pathways have been proposed. Based on the current evidence, clinicians should assess the risk of OSA in patients with type 2 diabetes and, conversely, consider that possibility of glucose intolerance in patients with OSA. Further large-scale and long-term follow-up studies in patient populations with selected by reliable but inexpensive diagnostic measures, controlled for potential confounder factor, are needed.

• Sleep Medicine and Psychophysiology
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• v.5 no.2
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• pp.210-215
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• 1998

OSA(Obstructive Sleep Apnea) is a condition with repeated obstruction of the upper airway while sleeping. This obstruction of the upper airway may result if sleep-induced physiologic change in muscle activity is superimposed on various structural defects of the upper airway. Macroglossia, micrognathia, retrognathia, and decreased airway lumen have all been implicated in OSA. There are a variety of surgical and nonsurgical treatment modalities currently available for OSA. Recently the uvulopalatopharyngoplasty has achieved widespread use, but success rates vary and long-term effects are still unknown. Current nonsurgical treatment methods can be cumbersome and uncomfortable with variable responses. For this case. we diagnosed as OSA by using polysomnographic analysis and cephalometric analysis, and delivered intraoral removable appliance which is more conservative, reversible and easy to use for patient. And we got results that Apnea Index(AI) decreased from 14.4 to 3.1, Total Respiratory Disturbance Index(Total RDI) decreased from 18.1 to 7.0 and removal of chronic headache in daytime.

• Korean Journal of Veterinary Service
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• v.34 no.4
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• pp.397-401
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• 2011

Aspiration of lytic bone lesions is an excellent diagnostic test in the initial evaluation of primary bone tumor. However, cytologically, it can be difficult to differentiate osteosarcoma (OSA) from other bone neoplasms, including fibrosarcoma, chondrosarcoma, synovial cell sarcoma, malignant fibrous histiocytoma and malignant peripheral nerve sheath tumor. The purpose of this study is to introduce alkaline phosphatase (ALP) staining to differentiate OSA from other mesenchymal tumors. Tumors actively producing bone are specifically positive for ALP staining. Unstained, cytologic specimens were incubated for 10 minutes with nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate toluidine salt-phosphatase substrate. Among 20 cases of cytology specimen, 14 were positive for ALP staining and histopathology, 6 were negative for ALP staining and histopathology. ALP staining was 100% sensitive and specificity for the diagnosis of OSA. Aspirate cytology with ALP staining was a simple, fast, safe and accurate diagnostic test for the evaluation of suspected OSA lesions in dogs.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.371-375
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• 2001

We have implemented a sensor head which consists of erbium doped fiber pumped by 1480 nm LD and single fiber Bragg grating for simultaneous measurement of strain and temperature. The measurement precision and speed are improved by using Mach-Zehnder interferometer instead of optical spectrum analyzer (OSA) as a demodulator. The measurement precision of temperature measured by the amplitude variation of output signal is 0.05$^{\circ}C$ and that of strain measured by the phase variation of output signal is 0.1$\mu$strain. The measurement precision of temperature and strain are improved nearly 140 times and 700 times, respectively, compared to those using an OSA with wavelength resolution of 0.97 nm as d demodulator.