• Journal of Korean Society of Water and Wastewater
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• 제18권3호
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• pp.307-311
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• 2004

The objective of this work is to evaluate the hypothesis that a good technique for supplying oxygen to the saturated zone in the presence of light nonaqueous phase liquid (LNAPL) pool contamination at the water table is to pass air through the unsaturated zone above the pool. This hypothesis was evaluated in experimental studies performed using a bench-scale, sand-tank reactor, Steady-state abiotic experiments in the sand-tank reactor with air flowing through the reactor headspace demonstrated that oxygen supply through the water table interface into the saturated zone was enhanced when an LNAPL (dodecane) pool was present at the water table. These experimental results confirmed the hypothesis that an LNAPL pool can serve as a high concentration oxygen source to the oxygen-limited area beneath the pool and, as a result, enhance the in situ biodegradation rate.

• Tuberculosis and Respiratory Diseases
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• 제62권5호
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• pp.382-388
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• 2007

Background: The cognitive function is impaired in patients with hypoxemic chronic obstructive pulmonary disease (COPD). However, there are conflicting results regarding the cognitive function in patients with non-hypoxemic COPD. COPD patients also have sleep disorders. This study examined the cognitive function in non-hypoxemic COPD patients, and nocturnal sleep was assessed in COPD patients with a cognitive dysfunction. Methods: Twenty-eight COPD patients (mean age, 70.7 years) with an oxygen saturation > 90%, and 33 healthy control subjects (mean age, 69.5 years) who had visited for a routine check-up were selected. The neurocognitive tests were performed using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) Neuropsychological Battery. Results: The scores of the word list recall test (p=0.03) and the word list recognition test (p=0.006) in the COPD group were significantly lower than those in the control group. Nine patients showed a significantly impaired cognitive function. Seven of these underwent polysomnography, which revealed apnea-hypopnea indices ${\geq}$ five per hour in five patients. The median oxygen desaturation index and median limb movement index were 3.6/h and 38.6/h, respectively. Conclusion: These results suggest that the verbal memory function is impaired in non-hypoxemic COPD patients. Six out of seven COPD patients with an impaired cognitive function had sleep disorders of sleep apnea and/or periodic limb movements during sleep.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제19권2호
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• pp.617-622
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• 2018

Air is essential for human beings to survive, but urban air is polluted with soot and harmful gases, due to the increase in industrial development and the population. Thus, air pollution in large cities is of increasing interest in the research community. One of the plausible solutions to this problem is supplying sufficient oxygen to indoor spaces. The main principle of the oxygen generator is to separate oxygen from air using synthetic zeolite. Various synthetic zeolites have been applied to public indoor spaces with the focus being placed on the oxygen exchange quality. Among the characteristics of zeolites which can be applied to oxygen generators is their ability to adsorb nitrogen from the air and, in this way, generate only oxygen. Thus, we investigated the degree of nitrogen adsorption by five kinds of natural zeolite and LTA zeolite 3A, 4A, and 5A (two different sizes). Using the PSA method, the higher the degree of nitrogen adsorption, the higher the oxygen saturation concentration, it was found that the nitrogen adsorption degree of the 5A zeolite was the highest. 6% on average. It was also found that the size of the zeolite had a significant effect on the degree of nitrogen adsorption.

• KSBB Journal
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• 제9권2호
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• pp.211-223
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• 1994

In fermentations with a 4-liter stirred tank bioreactor, a better than two-fold enhancement of the gas-liquid mass transfer coefficient$(k_La)$ in the celite-immobilized fungal cultures of Tolypocladium in flatum over the parallel conventional free-cell was observed at identical biomass concentrations, despite the higher specific oxygen uptake rate of the immobilized fungi during exponential growth. As a result oxygen sufficient conditions, i. e., dissolve oxygen(D.O.) concentrations exceeding 75% air saturation, could be maintained throughout exponential growth period of the immobilized culture, in contrast to the suspended fungal culture, whose D.O. levels fell below 50% air saturation. A linear monotonic dependence of $k_La$ upon impeller agitaion rate was found for both immobilized and conventional cultivation modes over a range of 250 to 550rpm, the slope being a function of biomass concentration for the free but not for the immobilized cell system In contrasts oxygen transfer rate was a much weaker function of aeration rate up to about 2.5 vvm for both culture configurations. Above this level, aeration rate had no further effect on the mass transfer. In addition, the immobilized cultures sustained good morphological and physiological states, leading to almost two times higher cyclosporln A (CyA) productivity overt the parallel free cell system. These experiments suggest that the celite-immobilized fungal system in a stirred tank reactor has considerable promise for scaling up cyclosporin A production in terms of high-density cultivation.

• Journal of the Korean earth science society
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• 제23권6호
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• pp.474-485
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• 2002

The object of this study is to investigate the contamination degree and the interpretation of sea water intrusion phenomena with hydrogeochemical and hydrogen-oxygen stable isotope of coastal aquifer in the Gogum area, Korea. The physical characteristics of groundwaters is the neutral pH condition and transitional Redox environments, and groundwater is affected by sea water & surface water. The chemical properties of groundwaters are showing an increase in contamination owing to the sea water intrusion, waste water from the surface and agricultural chemicals. In the case of chloride, 6 samples of the groundwater in the study area are in excess of the drinking water standard. The Piper diagram shows the contamination in GG-4 and 14 by sea water intrusion. GG-3, 7 and 13 dominate the Na-HCO$_{3}$ type water and regional (GG-14) is indicated to dominate the Na-Cl type water such as sea water. According to the Sl (saturation index), sea water is oversaturated with respect to calcite and dolomite, GG-3, 14 and 18 are approaching the saturation state. The hydrogen-oxygen stable isotope ratio of groundwaters originates in the meteoric water, and groundwaters of GG-1, 5 and 14 display high oxygen isotope value due to surface water trespass and sea water intrusion. The result of this study, GG-14 is contaminated by sea water intrusion, groundwaters expected GG-3, 7 and 13 is in progress to artificial pollution and sea water intrusion.

• Journal of The Korean Dental Society of Anesthesiology
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• 제10권2호
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• pp.159-165
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• 2010

배경: 매복지치의 수술적 발치 시 propofol과 remifentanil을 이용한 목표조절농도주입(Target controlled infusion) 의식하 정주진정법의 적절한 주입농도를 제시하고 그 안전성을 평가하고자 하였다. 방법: 매복지치의 수술적 발치가 예정된 미국마취학회 신체 등급 분류 1, 2에 속하는 15-65세, 142명(여 83명, 남 59명)의 환자를 대상으로 소급 연구하였다. 환자는 수술 전 목표조절농도주입법을 이용한 의식하 진정법 사용에 관한 동의서를 작성하였다. 정맥내 삽관을 시행하고 수액을 공급을 시작하고, 4-5 L/min의 산소를 비관을 통해서 공급하였다. Propofol과 remifentanil의 초기 목표 혈중농도는 각각 $0.5\;{\mu}g/ml$와 1.0 ng/ml로 정하였다. 수술 중, 환자의 불안 통증 정도에 따라 목표농도를 조절하였으며 최저 농도와 최대 농도, 평균 농도, 주입된 총 용량을 기록하였다. 또한 수축기혈압과 맥박 수, 산소포화도, 호기 말 이산화탄소량을 수술 시작 전, 수술 중 5분 간격으로 확인하고 기록하였다. 모든 측정치는 평균 $\pm$ 표준편차나 환자의 수, 초기 측정치에서의 백분율 편차로 표시하였다. 결과: 수술 동안의 목표 혈중농도의 평균은 propofol은 $0.54{\pm}0.11\;{\mu}g/ml$이고, remifentanil은 $1.11{\pm}0.30\;ng/ml$였다. 수술 중 조절된 최대농도는 propofol은 $0.6{\pm}0.23\;{\mu}g/ml$이고, remifentanil은 $1.3{\pm}0.63\;ng/ml$였다. 이는 의식하 진정에 해당되는 범의의 농도라고 할 수 있겠다. 진정동안 환자의 언어적 의사소통은 유지 되었으며 산소 포화도는 4-5 L/min 의 산소 보충 하에 98%이상으로 유지되었다. 수축기 혈압과 맥박은 대부분의 환자에서 정상변위범위(${\pm}20%$)내에서 유지되었다. 결론: 본 연구는 목표조절 농도주입 의식하 진정에서 사용된 농도(propofol $0.5\;{\mu}g/ml$, remifentanil 1.0 ng/ml)는 안전하게 의식하 진정을 가능한 것을 보여준다. 이는 치과 치료 시 목표조절농도 주입의식하 진정법에서 적절한 목표농도를 제시한다.

• The Korean Journal of Physiology
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• 제20권1호
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• pp.53-63
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• 1986

Carbon monoxide(CO) poisoning has been one of the major environmental problems because of the tissue hypoxia, especially brain tissue hypoxia, due to the great affinity of CO with hemoglobin. Inhalation of the pure oxygen$(0_2)$ under the high atmospheric pressure has been considered as the best treatment of CO poisoning by the supply of $0_2$ to hypoxic tissues with dissolved from in plasma and also by the rapid elimination of CO from the carboxyhemoglobin(HbCO). Hydrogen peroxide $(H_2O_2)$ was rapidly decomposed to water and $0_2$ under the presence of catalase in the blood, but the intravenous administration of $H_2O_2$ is hazardous because of the formation of methemoglobin and air embolism. However, it was reported that the enema of $H_2O_2$ solution below 0.75% could be continuously supplied $0_2$ to hypoxic tissues without the hazards mentioned above. This study was performed to evaluate the effect of $H_2O_2$ enema on the elimination of CO from the HbCO in the recovery of the acute CO poisoning. Rabbits weighting about 2.0 kg were exposed to If CO gas mixture with room air for 30 minutes. After the acute CO poisoning, 30 rabbits were divided into three groups relating to the recovery period. The first group T·as exposed to the room air and the second group w·as inhalated with 100% $0_2$ under 1 atmospheric pressure. The third group was administered 10 ml of 0.5H $H_2O_2$ solution per kg weight by enema immediately after CO poisoning and exposed to the room air during the recovery period. The arterial blood was sampled before and after CO poisoning ana in 15, 30, 60 and 90 minutes of the recovery period. The blood pH, $Pco_2\;and\;Po_2$ were measured anaerobically with a Blood Gas Analyzer and the saturation percentage of HbCO was measured by the Spectrophotometric method. The effect of $H_2O_2$ enema on the recovery from the acute CO poisoning was observed and compared with the room air group and the 100% $0_2$ inhalation group. The results obtained from the experiment are as follows: The pH of arterial blood was significantly decreased after CO poisoning and until the first 15 minutes of the recovery period in all groups. Thereafter, it was slowly increased to the level of the before CO poisoning, but the recovery of pH of the $H_2O_2$ enema group was more delayed than that of the other groups during the recovery period. $Paco_2$ was significantly decreased after CO poisoning in all groups. Boring the recovery Period, $Paco_2$ of the room air group was completely recovered to the level of the before CO Poisoning, but that of the 100% $O_2$ inhalation group and the $H_2O_2$ enema group was not recovered until the 90 minutes of the recovery period. $Paco_2$ was slightly decreased after CO poisoning. During the recovery Period, it was markedly increased in the first 15 minutes and maintained the level above that before CO Poisoning in all groups. Furthermore $Paco_2$ of the $H_2O_2$ enema group was 102 to 107 mmHg and it was about 10 mmHg higher than that of the room air group during the recovery period. The saturation percentage of HbCO was increased up to the range of 54 to 72 percents after CO poisoning and in general it was generally diminished during the recovery period. However in the $H_2O_2$ enema group the diminution of the saturation percentage of HbCO was generally faster than that of the 100% $O_2$ inhalation group and the room air group, and its diminution in the 100% $O_2$ inhalation group was also slightly faster than that of the room air group at the relatively later time of the recovery period. In conclusion, the enema of 0.5% $H_2O_2$ solution is seems to facilitate the elimination of CO from the HbCO in the blood and increase $Paco_2$ simultaneously during the recovery period of the acute CO poisoning.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제14권5호
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• pp.1303-1310
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• 2010

Recently, researches related with automative mechanism have been widely studied to increase the driver's safety by continuously monitoring the driver's health condition to prevent driver's drowsiness. This paper describes the design of wearable chest belt for ECG and reflectance pulse oximetry for SpO2 sensors based on wireless sensor network to monitor the driver's healthcare status. ECG, SpO2 and heart rate signals can be transmitted via wireless sensor node to base station connected to the server. Intelligent monitoring system is designed at the server to analyze the SpO2 and ECG signals. HRV (Heart Rate Variability) signals can be obtained by processing the ECG and PPG signals. HRV signals are further analyzed based on time and frequency domain to determine the driver's drowsiness status.

• Sleep Medicine and Psychophysiology
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• 제13권2호
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• pp.45-51
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• 2006

Obstructive sleep apnea (OSA) syndrome disrupts normal sleep. However, there were few studies to evaluate the asymmetric distribution, the one of the important factors of normal sleep in OSA subjects. We hypothesized that asymmetry would be broken in OSA patients. 49 male subjects with the complaint of heavy snoring were studied with polysomnography. We divided them into two groups based on the apnea-hypopnea index (AHI) fifteen: 13 simple snoring group (SSN, average AHI $5.9{\pm}4.4$) and 32 OSA group (average AHI $47.3{\pm}23.9$). We compared split sleep variables between the first half and the second half of sleep within each group with paired t-test for the evaluation of asymmetry. Changes of sleep architecture of OSA were higher stage 1 sleep% (S1), total arousal index (TAI), AHI, and mean heart rate (HR) and lower stage 2 sleep% (S2), REM sleep%, and mean arterial O2 saturation (SaO2) than SSN subjects. SWS and wake time after sleep onset (WASO) were not different between two groups. In split-night analysis, OSA subjects showed higher S2, slow wave sleep% (SWS), spontaneous arousal index (SAI), and mean HR in the first half, and higher REM sleep% and mean SaO2 in the second half. Those were same pattern as in SSN subjects. Mean apnea duration and longest apnea duration were higher in the second half only in the OSA. No differences of AHI, ODI, WASO, and S1 were found between the first and the second half of sleep in both groups. TAI was higher in the first half only in the SSN. SWS and WASO seemed to be influenced sensitively by simple snoring as well as OSA. Unlike our hypothesis, asymmetric distributions of major sleep architecture variables were preserved in OSA group. Losing asymmetry of TAI might be related to pathophysiology of OSA. We need more studies that include large number of subjects in the future.

• Sleep Medicine and Psychophysiology
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• 제12권1호
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• pp.39-44
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• 2005

Objectives: Much attention has been paid to sleep apnea syndrome (SAS) in the elderly because of its high prevalence. It is expected that SAS in the elderly has both similarities and differences compared to SAS in the young or middle-aged populations. The aim of this study was to elucidate the characteristics and consequences of SAS in the elderly. Methods: In this study we included 210 young or middle-aged adults between 23 and 59 years (20 women and 190 men) and 65 older adults between 60 and 83 years of age (16 women and 49 men). Respiratory disturbance indices (RDIs) of the study subjects were more than 5 in an overnight polysomnography. They completed the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Informations about body mass index (BMI), neck, waist, and hip measurements, and blood pressure were obtained. Results: No difference was observed between older adults with SAS (older SAS) and adults aged under 60 with SAS (SAS aged under 60) in RDI, apnea index, % time of oxygen saturation less than 90%, and PSQI. Obstructive apnea index and oxygen desaturation index (ODI) were lower in older SAS. Compared to SAS aged under 60, lowest oxygen saturation and central apnea index were higher in older SAS, but they were statistically not significant. BMI and neck circumference were significantly lower in older SAS compared to SAS aged under 60. Diastolic blood pressure was lower in older SAS compared to SAS aged under 60 with no difference in systolic blood pressure. Older SAS showed lower scores in ESS than SAS aged under 60. Significant correlation was observed between RDI and BMI in SAS aged under 60, but not in the case of older SAS. The relationships between RDI and neck circumference, systolic and diastolic pressure, and ESS were similar. Conclusions: The elderly with SAS were not over-weight and there was no relationship between body weight and the severity of SAS. Also, the behavioral and cardiovascular effects of SAS were not marked in the elderly, which might be partly explained by decreased ODI and relatively higher lowest oxygen saturation in older SAS. The normal aging process, aside from increased body weight, might contribute to the development of SAS in the elderly with modest complications.