• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1252-1264
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• 1998

Background : Patients with established ARDS have a mortality rate that exceeds 50 percent despite of intensive care including artificial ventilation modality, Mortality has been associated with sepsis and organ failure preceding or following ARDS ; APACHE II score ; old age and predisposing factors. Revised ventilator strategy over last 10 years especially at ARDS appeared to improve the mortality of it. We retrospectively investigated 40 ARDS patients of respiratory-care unit to examine how these factors influence outcome. Methods : A retrospective investigation of 40 ARDS patients in respiratory-care unit with ventilator management over 46 months was performed. We investigated the clinical characteristics such as a risk factor, cause of death and mortality, and also parameters such as APACHE II score, number of organ dysfunction, and hypoxia score (HS, $PaO_2/FIO_2$) at day 1, 3, 7 of severe acute lung injury, and simultaneously the PEEP level and tidal volume. Results : Clinical conditions associated with ARDS were sepsis 50%, pneumonia 30%, aspiration pneumonia 20%, and mortality rate based on the etiology of ARDS was sepsis 50%, pneumonia 67%(p<0.01 vs sepsis), aspiration pneumonia 38%. Overall mortality rate was 60%. In 28 day-nonsurvivors, leading cause of death was severe sepsis(42.9%) followed by MOF(28.6%), respiratory failure(19.1 %), and others(9.5%). There were no differences in variables of age, sex, APACHE II score, HS, and numbers of organ dysfunction at day 1 of ARDS between 28-days survivor and nonsurvivors. In view of categorized variables of age(>70), APACHE II score(>26), HS(<150) at day 1 of ARDS, there were significant differences between 28-days survivor and nonsurvivors(p<0.05). After day 1 of ARDS, the survivors have improved their APACHE II score, HS, numbers of organ dysfunction over the first 3d to 7d, but nonsurvivors did not improve over a seven-day course. There were significant differences in APACHE II score and numbers of organ dysfunction of day 3, 7 of ARDS, and HS of day 7 of ARDS between survivors and nonsurvivors(p<0.05). Fatality rate of ARDS has been declined from 68% to less than 40% between 1995 and 1998. There were no differences in APACHE II score, HS, numbers of organ dysfunction, old age at presentation of ARDS. In last years, mean PEEP level was significantly higher and mean tidal volume was significantly lower than previous years during seven days of ARDS(p<0.01). Conclusions : Improvement of HS, APACHE II score, organ dysfunction over the first 3d to 7d is associated with increased survival Decline in ARDS fatality rates between 1995 and 1998 seems that this trend must be attributed to improved supportive therapy including at least high PEEP instead of conventional-least PEEP approach in ventilator management of acute respiratory distress syndrome.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.581-586
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• 2014

Main objects for wastewater treatment operation are to maintain effluent water quality and minimize operation cost. However, the optimal operation is difficult because of the change of influent flow rate and concentrations, the nonlinear dynamics of microbiology growth rate and other environmental factors. Therefore, many wastewater treatment plants are operated for much more redundant oxygen or chemical dosing than the necessary. In this study, the optimal control scheme for dissolved oxygen (DO) is suggested to prevent over-aeration and the reduction of the electric cost in plant operation while maintaining the dissolved oxygen (DO) concentration for the metabolism of microorganisms in oxic reactor. The oxygen uptake rate (OUR) is real-time measured for the identification of influent characterization and the identification of microorganisms' oxygen requirement in oxic reactor. Optimal DO set-point needed for the micro-organism is suggested based on real-time measurement of oxygen uptake of micro-organism and the control of air blower. Therefore, both stable effluent quality and minimization of electric cost are satisfied with a suggested optimal set-point decision system by providing the necessary oxygen supply requirement to the micro-organisms coping with the variations of influent loading.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.50-55
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• 2009

Purpose : This study aimed to determine the influence of low-dose oxygen ($FiO_2$ <25%) therapy through nasal cannulae on the progress and prognosis of retinopathy of prematurity (ROP) as well as methods of preventing ROP. Methods : Our subjects comprised premature infants (gestation period <37 weeks; birth weight <1,750 g) born in Daegu Fatima Hospital between February 1, 2001 and January 31, 2006. We retrospectively reviewed and analyzed the medical records of 273 patients who were available for eye examination and follow up over 6 months. Results : The factors maximally influencing the occurrence of ROP were low gestation age and low birth weight. We observed that the incidence of ROP increased with the increasing duration of low-dose oxygen therapy. ROP onset was delayed during ongoing oxygen therapy; however, rapid progression of ROP occurred after the discontinuation of oxygen therapy among premature infants up to the prethreshold stage. Conclusion : To prevent of occurrence of severe ROP and its rapid progression, the period of low-dose oxygen therapy needs to be shortened. Moreover, frequent eye examinations should be performed after the discontinuation of oxygen therapy.

• The Korean Journal of Zoology
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• v.29 no.3
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• pp.201-207
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• 1986

The authors attempted to investigate the oxygen consumption rate of sexuals in the water-striders, Gerris paludum insuralis, at four temperature groups of 25, 30, 35 and $40^\\circ C$ in a series of studies on respiration of a heminetabolous insects. THe results are summarised as follows: (1) At $30^\\circ C$, the change of oxygen consumption rate according to the lapse of time was small in comparison with the other three temperature groups which shows a cyclic decreasing pattern. The rate during initial and final 5 minutes was much alike. Thereupon, the optimum temperature was regarded as $30^\\circ C$. (2) The oxygen consumption rate of male was higher than that of female. (3) The oxygen consumption rates at 25, 30, 35 and $40^\\circ C$ were 0.42, 0.49, 0.79 and 1.11 $\\mu$l/mg/h respectively. That is, the rate was increased as the temperature was increased. (4) The $Q_10$ of male showed a high value in the lower temperature interval ($25^\\circ C \\sim 35^\\circ C$), but the female showed a high value in the higher temperature interval ($30^\\circ C \\sim 40^\\circ C$). The mean $Q_10$ was 2.12. (5) The respiratory rate was decreased as the body weight was increased in the above fresh weight of 10mg and dry weight 5 mg. (6) The upper temperature threshold for respiration was $48.31^\\circ C$ and the lower temperature threshold was $17.68^\\circ C$. (7) The ceasing time of breathing at the other three temperature groups except $30^\\circ C$ was infered to be about 110 minutes after the start of experiment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.57-60
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• 2001

미생물 활성도와 그에 따른 유기물의 분해율은 미생물의 호흡률과 직접적인 관계가 있다. 본 연구는 매립종료후 경과기간이 1년인 Y 매립지와 10년인 C 매립지의 오염특성을 조사하였고, 오염토양 미생물의 산소소비속도를 이용하여 매립종료기간에 따른 오염토양의 산소소비율을 비교 평가 하고자 하였다. C 매립지의 오염토양에 대한 SCO $D_{cr}$ TOC는 Y 매립지에 비해 낮은 함량으로 나타났으나 T-N, N $H_3$-N의 함량은 큰 차이를 보이지 않았다. TOC/T-N비로 보았을 때 Y 매립지에 비해 C 매립지가 낮은 것으로 나타나 연령이 많은 경우 분해성 유기물의 함량은 적은 것으로 판단된다. 산소소비율 실험결과 Y 매립지가 산소소비율이 높은 것으로 나타났으며, C 매립지도 대조토양에 비해 높은 산소소비율을 보였다. 따라서 매립종료 후 경과기간이 10년인 매립지의 미생물의 산소소비율을 보았을 때 여전히 생물학적 안정화가 종료되지 않은 것을 알 수 있었다.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.138-144
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• 2008

The effects of salinity on oxygen consumption, operculum movement number and ammonia nitrogen excretion were examined in cultured tilapia, Oreochromis mossambicus (total length 10$\pm$1.0 cm, total weight 17.3$\pm$4.2 g). The fish were exposured to certain salinities (0, 3, 9, 15, 21, 27 and 32 psu) step by step with 3 psu$\cdot$d$^{-1}$ and changed rapidly from certain salinity to another salinity. The oxygen consumption of the fish which was transferred step by step showed increasing tendency in the range of 3 $\sim$ 27 psu, but markedly appeared very low value at 32 psu. The tolerance limit in tilapia by salinity change without acclimation was shown 23.3 psu from 96-h TL$_{50}$. The oxygen consumption, operculum movement and ammonia nitrogen excretion of fish which was transferred rapidly from certain salinity to each salinity (0, 9, 15, 21 and 32 psu) showed a changing point at 15 psu; they showed increasing and/or decreasing pattern before 15 psu, and showed decreasing pattern after 15 psu. From these results, it was concluded that the appropriate salinity without physiological change for Java tilapia was below 15 psu.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.485-489
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• 2002

To investigate the effects of the dissolved oxygen concentration (DO) of Tetillarca granosa (Linnaeus), We measured $LC_{50}$, survival, oxygen consumption rate, filtration rates and blood composition under $10{\cdot}{\pm}0.5^{\circ}C$ and $25{\cdot}0.5^{\circ}C$ as a function of DO. The 16 days-$LC_{50}$ of DO for T. granosa was 1.31 mg DO/L in large individual and 0.95 mg DO/L in small individual. At 25$^{\circ}C$, the $LC_{50}$ of DO in large and small individual was 1.13 and 1.M mg DO/L, respectively. With decreasing DO, oxygen consumption rate, and filtration rates of T. granosa decreased. Blood composition of T. granosa was analysed hemoglobin, glucose, total protein, total cholesterol, GOT and GPT, Hg was increased with decreasing DO, but glucose was decreased below 1.2 mg DO/L. Total protein, total cholesterol, GOT and GPT were investigated irregular and decreasing aspect.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.337-344
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• 2001

The combination of chloral hydrate and hydroxyzine is one of the safest and most commonly used drug regimens for sedating young, uncooperative pediatric dental patients. The continuous monitoring of respiratory function and early recognition of respiratory difficulties are essential for the successful management of sedated dental patients. The purpose of this study was to evaluate the success rate of the sedation and the hypoxia through monitoring the oxygen desaturation in the pulse oximeter in pediatric dental patients sedated with 60mg/kg chloral hydrate and 25mg hydroxyzine. The following results were obtained : 1. The success rate of the sedation was 69.6% and there was no statistically significant difference among the groups based on the ages, weight and duration of the operative time. 2. Forty two percentage of the sedated patients showed the temporary hypoxia state and there was no statistically significant difference based on the ages and weights of the patients. But there was a statistically significant difference on the duration of the operative time.

• The Korean Journal of Malacology
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• v.14 no.1
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• pp.51-59
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• 1998

담수산 이매패류인 참재？, Corbicula leana를 대상으로 크기와 수온별로 카드뮴, 구리 및 수은 등의 중금속에 노출시켜 반수치사농도, 호흡률 및 여수율 등의 생리적 내성에 관하여 알아보았다. 17%C에서 작은 개체rnhr,-LC$^{50}$ 은 수은이 1.63 ppm이었으며, 카드뮴과 구리는 각각 7.45및 8.71 ppm으로서 수은에 비해 상당히 높은 값을 나타내었다. 큰 개체구의 경우는 수은이 2.62ppm이었으며, 카드뮴과 구리가 각각10.15와 10.20 ppm이었다. 22$^{\circ}C$의 경우 작은 개체구의 96 hr-LC$^{50}$ ppm은 카드뮴, 구리 및 수은이 각각 5.94, 7.08및 1.63 ppm이었으며, 큰 개체구에서는 각각 8.29, 8.35, 1.87ppm으로서 두수온구에서 모두 작은 개체구에서 중금속 오염원에 의한 영향이 컸으며, 독성순위는 수은>카드뮴>구리 순이었다. 한편 중금속 오염원에 노출시킨 참재첩의 수온-개체크기별 산소소비율과 여수율은 오염원의 농도증가에 따라 고수온에서 영향을 많이 받았으며, 특히 수은의 경우, 22%C-작은 개체구에서 호흡률이 50.7%, 여수율이 52.15%감소되고 있어 여수율이 보다 크게 영향을 받았다.

• Korean Journal of Environmental Biology
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• v.31 no.3
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• pp.204-212
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• 2013

This study analyzed the occurrence of tunic softness, survival rate, metabolic rate and histopathologic changes arising from the effect of hypoxic environment in order to find the causes of occurrences of tunic softness, which manifests as the key phenomenon of mass mortality of Halocynthia roretzi. Regarding the survival of H. roretzi with reduction in dissolved oxygen, all the entities died on the 4th day of exposure to the dissolved oxygen concentration of $2mg\;L^{-1}$ while 50% mortality was observed on the 5th day of exposure to the dissolved oxygen concentration of $3mg\;L^{-1}$. Therefore the 5 days-$LC_{50}$ was found to be $3.55mg\;L^{-1}$ (1.86~$4.96mg\;L^{-1}$). However, occurrence of tunic softness was not observed during the period of exposure to low oxygen concentration. The oxygen consumption rate significantly decreases at the dissolved oxygen concentration of less than $5mg\;L^{-1}$ in comparison to the control group. Therefore, it is presumed that H. roretzi controls the respiration rate for prescribed period of time when exposed to hypoxic environment. Regarding the histopathologic changes in the gill, digestive gland and cyst of H. roretzi due to hypoxic environment, necrosis of epithelial layer, in filtration of blood cells, and condensation of nucleus that compose each of the organs were observed. Regarding morphological changes, the decrease in volume with shrinking of the tunic, discoloration of the internal organs and necrosis of gill and hepatopancreas were observed.