• Title/Summary/Keyword: Constant Parameters

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Seasonal Distribution of Water Masses and Spatio-temporal Characteristics of Nutrients in the Coastal Areas of Gangwon Province of the Korean East Sea in 2009 (2009년 강원 연안의 계절별 수괴 분포 및 영양염의 시공간적 특성)

  • Choi, Mi-Yeon;Moon, Deok-Soo;Jung, Dong-Ho;Kim, Hyeon-Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.2
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    • pp.76-88
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    • 2012
  • In order to investigate the distribution of water masses and spatio-temporal variation of nutrients in the coastal areas of Gangwon province of the Korean East Sea, a survey of the physico-chemical parameters (temperature and salinity) and nutrients ($NO_2$-N, $NO_3$-N, $NH_4$-N, $PO_4$-P, and $SiO_2$-Si) was carried out at 5 locations (Goseong, Sokcho, Yangyang, Gangneung, and Donghae) in February, May, August, and November 2009. The water masses included in the study area were divided into 4 groups; 1) Tsushima Surface Water (TSW), 2) Tsushima Middle Water (TMW), 3) North Korean Cold Water (NKCW), and 4) East Sea Proper Water (ESPW). The distribution of water masses was affected by the change of season. In February, surface water was derived from the TMW. The TSW was not observed in May, but only observed in August. In November, as the influence of the TSW weakened, that of the NKCW strengthened. Considering the vertical profiles of nutrients, the concentrations in all the seasons were very low within the surface water, but increased rapidly near the thermocline. Most of nutrient concentrations, except for dissolved silicate, remained constant below the depth of 200 m. However, the dissolved silicate concentration increased with depth, suggesting that silicate has a delayed regenerative pattern. The ESPW had the highest nutrient concentration, followed by the NKCW, TMW, and TSW. In February, May, and November, the N/P ratio in most of the water masses was similar to or larger than the Redfield ratio, indicating that nitrogenous nutrients did not act as a limiting factor for phytoplankton growth. However, in August, the N/P ratio in the TSW was less than the Redfield ratio, and the concentration of $NO_2$-N+$NO_3$-N was 0.86 ${\mu}m$, indicating that nitrogenous nutrients did act as a limiting factor for phytoplankton growth in the study area.

Electrical Stimulation Parameters in Normal and Degenerate Rabbit Retina (정상 망막과 변성 망막을 위한 전기자극 파라미터)

  • Jin, Gye-Hwan;Goo, Yong-Sook
    • Progress in Medical Physics
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    • v.19 no.1
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    • pp.73-79
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    • 2008
  • Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa (RP) or age related macular degeneration (AMD). Recently Korean consortium launched for developing retinal prosthesis. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we performed voltage stimulation experiment both in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: $50k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. Mono-polar electrical stimulation was applied through one of the 60 MEA channel, and the remaining channels were used for recording. The electrical stimulus was a constant voltage, charge-balanced biphasic, anodic-first square wave pulse without interphase delay, and 50 trains of pulse was applied with a period of 2 sec. Different electrical stimuli were applied. First, pulse amplitude was varied (voltage: $0.5{\sim}3.0V$). Second, pulse duration was varied $(100{\sim}1,200{\mu}s)$. Evoked responses were analyzed by PSTH from averaged data with 50 trials. Charge density was calculated with Ohm's and Coulomb's law. In normal retina, by varying the pulse amplitude from 0.5 to 3V with fixed duration of $500{\mu}s$, the threshold level for reliable ganglion cell response was found at 1.5V. The calculated threshold of charge density was $2.123mC/cm^2$. By varying the pulse duration from 100 to $1,200{\mu}s$ with fixed amplitude of 2V, the threshold level was found at $300{\mu}s$. The calculated threhold of charge density was $1.698mC/cm^2$. Even after the block of ON-pathway with L-(1)-2-amino-4-phosphonobutyric acid (APB), electrical stimulus evoked ganglion cell activities. In this APB-induced degenerate retina, by varying the pulse duration from 100 to $1200{\mu}s$ with fixed voltage of 2 V, the threshold level was found at $300{\mu}s$, which is the same with normal retina. More experiment with APB-induced degenerate retina is needed to make a clear comparison of threshold of charge density between normal and degenerate retina.

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Clinical Significance of Nasal Peak Inspiratory Flow Rate in Patients with Chronic Cough (만성기침환자에서 비강최대흡기유속 측정의 의의)

  • An, Chang-Hyeok;Lee, Byung-Hun;Park, Yong-Bum;Choi, Jae-Chul;Jee, Hyun-Suk;Park, Sung-Jin;Kang, Sun-Bok;Kim, Jae-Yeol;Park, In-Won;Choi, Byung-Whi;Hue, Sung-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.46 no.5
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    • pp.654-661
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    • 1999
  • Background : The upper respiratory tract is the primary target organ of various airborne pollutants and is easily accessible part of the respiratory tract, and also is the predominant structure where chronic cough originates. The nasal peak inspiratory flow(PIFn), which is the peak inspiratory flow via nose with nasal mask and spirometry, could be a reliable parameter of nasal obstruction. The validity of PIFn has been evaluated in several studies by assessing the correlation between PIFn measurements and other parameters of nasal air flow. This study was designed to show the reproducibility of PIFn, the difference of PIFn between patients with chronic cough and normal subjects, and the usefulness of PIFn in the evaluation of nasal obstruction in patients with chronic cough. Methods : PIFn was measured by spirometry with nasal mask, twice a day for 3 consecutive days in 7 young normal subjects to evaluate validity of the test. In 32 patients with chronic cough and 25 age-matched normal subjects, PIFn and pulmonary function test($FEV_1$, $FEV_1%$ pred, FVC, and FVC% pred) were measured at first visiting. Results : Values of PIFn, $FEV_1$, and FVC were nearly constant in 7 young normal adults. Patients with chronic cough were 32 (14 males and 18 females) and the mean age was $41.4{\pm}15.9$ years. Normal subjects were 32(22 males and 10 females) and the mean age was $39.8{\pm}18.6$ years. There was no significant difference of age and pulmonary function test between patients with chronic cough and normal subjects(p<0.05). The PIFn values in patients with chronic cough was significantly lower than those of normal subjects($2.25{\pm}0.68\;L/sec$ vs. $2.75{\pm}1.00\;L/sec$ ; p=0.02). The postnasal drip syndrome(PNDS) comprised the majority of patients with chronic cough(27). The PIFn in patients with PNDS was significantly lower than that of normal subjects (mean$\pm$SD ; $2.18{\pm}0.66$ vs. $2.75{\pm}1.00\;L/sec$, p=0.006). Conclusion : There was a significant difference of PIFn between patients with chronic cough and normal subjects. Among the patients with chronic cough, patients with PNDS showed the most significant difference with normal subjects in PIFn. The PIFn could be a useful parameter of nasal obstruction in patients with chronic cough, especially in patients with PNDS.

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The Comparison of Absolute Dose due to Differences of Measurement Condition and Calibration Protocols for Photon Beams (6MV 광자선에서 측정 조건의 변화와 측정법의 차이에 의한 절대 선량값의 비교)

  • 김회남;박성용;서태석;권수일;윤세철
    • Progress in Medical Physics
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    • v.8 no.2
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    • pp.87-102
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    • 1997
  • The absolute absorbed dose can be determined according to the measurement conditions; measurement material, detector, energy and calibration protocols. The purpose of this study is to compare the absolute absorbed dose due to the differences of measurement condition and calibration protocols for photon beams. Dosimetric measurements were performed with a farmer type PTW and NEL ionization chambers in water, solid water, and polystyrene phantoms using 6MV photon beams from Siemens linear accelerator. Measurements were made along the central axis of 10cm $\times$ 10cm field size for constant target to surface distance of 100cm for water, solid water and polystyrene phantom. Theoretical absorbed dose intercomparisons between TG21 and IAEA protocol were performed for various measurement combinations of phantom, ion chamber, and electrometer. There were no significant differences of absorbed dose value between TG21 and IAEA protocol. The differences between two protocols are within 1% while the average value of IAEA protocol was 0.5% smaller than TG21 protocol. For the purpose of comparison, all the relative absorbed dose were nomalized to NEL ion chamber with Keithley electrometer and water phantom, The average differences are within 1%, but individual discrepancies are in the range of - 2.5% to 1.2% depending upon the choice of measurement combination. The largest discrepancy of - 2.5% was observed when NEL ion chamber with Keithley electrometer is used in solid water phantom. The main cause for this discrepancy is due to the use of same parameters of stopping power, absorption coeficient, etc. as used in water phantom. It should be mentioned that the solid water phantom is not recommended for absolute dose calibration as the alternative of water, since absorbed dose show some dependency on phantom material other than water. In conclusion, the trend of variation was not much dependent on calibration protocol. However, it shows that absorbed dose could be affected by phantom material other than water.

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Effect of Different Seasons on the Performance of Grey Giant Rabbits under Sub-Temperate Himalayan Conditions

  • Bhatt, R.S.;Sharma, S.R.;Singh, Umesh;Kumar, Davendra;Bhasin, V.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.6
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    • pp.812-820
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    • 2002
  • An experiment was conducted on 190 progeny (winter -74; summer -59; rainy -57) of 12 Grey Giant rabbits (10 female +2 males), to assess the effect of different seasons in a year, on their reproductive, growth and productive performances along with feed efficiency, under sub-temperate Himalayan conditions. The daily meteorological attributes recorded during winter (October to March), summer (April to June) and rainy (July to September) seasons, and analysed were minimum and maximum temperature, relative humidity and rainfall. Various biological parameters recorded were doe weights at mating and kindling, litter size at birth, litter weight at birth, kit mortality, litter size at weaning, litter weight at weaning, weekly body weight up to 98 d and weaner mortality. Individual weight gains, dressing percentages, meat weights, liver weights, raw-pelt weights, processed pelt weights and processed pelt areas at slaughter on d 84 and 98, respectively were also recorded. The feed and fodder compositions and their nutritive values during different seasons were also analysed. Average ambient temperature during winter, summer and rainy seasons were $13.2{\pm}2.8$, $22.4{\pm}3.7$ and $24.8{\pm}2.3^{\circ}C$, respectively. The average relative humidity and total rainfall for winter, summer and rainy seasons were $68.9{\pm}1.5$% and $48{\pm}26.6$mm, $66.3{\pm}4.8$% and $125.6{\pm}56.8$ mm, and $77.3{\pm}1.3$% and $116.3{\pm}90.4$ mm, respectively. The weight of doe at mating and kindling, litter size at birth, litter weight at birth and litter size at weaning were comparatively higher whereas litter weight at weaning was significantly (p<0.05) higher during winter as compared to summer and rainy seasons. The kit mortality was significantly (p<0.05) higher during winter while the weaner mortality was significantly (p<0.05) higher during rainy season. At 84 d, the live weight per doe, slaughter weight, dressing percentage and liver weight were significantly (p<0.05) higher during winter than summer and rainy. Similarly, the gain in weight and meat weight at 84 and 98 d were significantly (p<0.05) higher during winter. The weight of raw pelt and processed pelt were recorded significantly (p<0.05) higher during winter while no difference in the area of processed pelts during different seasons could be observed. No difference in the biological performance could be observed between sexes in any of the seasons. Roughage analysis revealed comparatively higher crude protein percent and lower crude fibre percent during summer and rainy seasons than in winter. The roughage dry matter intake was comparatively higher during summer and rainy seasons vis-a-vis constant amount of concentrate supplied during all the three seasons. The digestibilities of dry matter was significantly (p<0.05) lower, whereas that of crude fiber, acid detergent fibre and cellulose were negative during winter. Interestingly, the feed:gain was exceedingly well during winter than in other seasons and it is concluded that it was the best season for production of rabbits under sub-temperate Himalayan conditions.

Effects of Arc Number or Rotation Range upon Dose Distribution at RapidArc Planning for Liver Cancer (간암환자를 대상으로 한 래피드아크 치료계획에서 아크수 및 회전범위가 선량분포에 미치는 영향)

  • Park, Hae-Jin;Kim, Mi-Hwa;Chun, Mi-Son;Oh, Yeong-Teak;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.21 no.2
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    • pp.165-173
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    • 2010
  • In this paper, we evaluated the performance of 3D CRT, IMRT and three kind of RA plannings to investigate the clinical effect of RA with liver cancer case. The patient undergoing liver cancer of small volume and somewhat constant motion were selected. We performed 3D CRT, IMRT and RA plannings such as 2RA, limited triple arcs (3RA) and 3MRA with Eclipse version 8.6.15. The same dose volume objectives were defined for only CTV, PTV and body except heart, liver and partial body in IMRT and RA plannings. The steepness of dose gradient around tumor was determined by the Normal Tissue Objective function with the same parameters in place of respective definitions of dose volume objectives for the normal organs. The approach between the defined dose constraints and the practical DVH of CTV, PTV and Body was the best in 3MRA and the worst in IMRT. The DVHs were almost the same among RAs. Plans were evaluated using Conformity Index (CI), Homogeneity Index (HI) and Quality of coverage (QoC) by RTOG after prescription with dose level surrounding 98% of PTV in the respective plans. As a result, 3MRA planning showed the better favorable indices than that of the others and achieved the lowest MUs. In this study, RA planning is a technique that is possible to obtain the faster and better dose distribution than 3D CRT or IMRT techniques. Our result suggest that 3MRA planning is able to reduce the MUs further, keeping a similar or better targer dose homogeneity, conformity and sparing normal tissue than 2RA or 3RA.

Thermal-Denaturation of File Fish Myofibrillar Protein and Protective Effect of Sucrose, Sorbitol and Amino Acids (말쥐치 근원섬유단백질의 열안정성과 및 가지 첨가제의 영향)

  • CHOI Young-Joon;PYEUN Jae-Hyeung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.5
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    • pp.455-463
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    • 1985
  • Thermal-denaturation of myofibrillar protein of dorsal skeletal muscle from file fish was investigated by measuring denaturation constant($K_D$) and thermodynamic parameters at various temperatures. The protective effects of sucrose, sorbitol and amino acids when added individually or combined were also discussed. The denaturation rate as reflected in inactivation of myofibrillar protein Ca-ATPase was followed the first order reaction. The $K_D$ values at $25^{\circ}C,\;30^{\circ}C,\;and\;35^{\circ}C$ were $19.52{\times}10^{-5},\;112.25{\times}10^{-5},\;and\;247.20{\times}10^{-5}$, respectively. The activation energy of the reaction at $30^{\circ}C$ was 43 kcal/mole. The protective effects of sucrose, sorbitol, glycine, alanine and Na-glutamate were increased with the concentration but the effects of sorbitol and Na-glutamate decreased beyond 1.0 mole. Basic amino acids such as arginine and lysine did not revealed any protective effect on the thermal denaturation. In case of mixed addition, the effects of Na-glutamate to glycine, sorbitol to glycine, and sorbitol to sucrose or sorbitol to Na-glutamate were enhanced 1.2 to 7.0 times as much as that of control (ratio of mixing; 1:1, range of concentration; 0.5 to 1.25 mole). Under the frozen condition at $-20^{\circ}C$, two mixtures such as Na-glutamate to glycine and sorbitol to sucrose apparently revealed the protective effects.

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Effect of Sodium ion on the Anaerobic Degradation of Food Waste : Quantitative Evaluation, Inhibition Model (주방폐기물의 혐기성분해에 대한 나트륨이온의 영향: 저해 특성평가, 저해모델)

  • Shin, Hang-Sik;Song, Young-Chae;Paik, Byeong-Cheon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.2 no.2
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    • pp.3-17
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    • 1994
  • The inhibitory effect of sodium ion on the anaerobic degradation of food waste was studied by an anaerobic batch toxicity assay and inhibition model. The anaerobic degradation activity of food waste spiked with over $2g\;Na^+/L$ of sodium ion was severely inhibited at the initial stage of the exposure. The inhibition response of anaerobic microorganisms on the sodium ion estimated from the methane production was differed according to the concentration of sodium ion. The relative acclimation time(RAT) and methanation rate(RMR), defined as the ratios of initial lag time and maximum methane production rate of the sample spiked with sodium ion to the control. respectively, were used to evaluate the acclimation and inhibitory effects quantitatively on the anaerobic microorganisms. When sodium ion was increased from $2g\;Na^+/L$ to $20g\;Na^+/L$, the RAT was exponentially increased from 18.9 to 90. but the RMR was linearly decreased from 0.97 to 0.02. The effects of sodium ion for the maximum methanation rate, first order kinetic constant and ultimate methane production were well evaluated by a generalized nonlinear expression model. it could be described by the uncompetitive inhibition mode. The sodium ion concentration causing 50% inhibition of methanation activity was about $11g\;Na^+/L$, and the critical sodium ion beyond to compelete inhibition was 20 to $21g\;Na^+/L$. The presented results could be used to obtain the design or operation parameters of the anaerobic process treating food waste of high salt.

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Estimating the Changes in Forest Carbon Dynamics of Pinus densiflora and Quercus variabilis Forests in South Korea under the RCP 8.5 Climate Change Scenario (RCP 8.5 기후변화 시나리오에 따른 소나무림과 굴참나무림의 산림 탄소 동태 변화 추정 연구)

  • Lee, Jongyeol;Han, Seung Hyun;Kim, Seongjun;Chang, Hanna;Yi, Myong Jong;Park, Gwan Soo;Kim, Choonsig;Son, Yeong Mo;Kim, Raehyun;Son, Yowhan
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.17 no.1
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    • pp.35-44
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    • 2015
  • Forests contain a huge amount of carbon (C) and climate change could affect forest C dynamics. This study was conducted to predict the C dynamics of Pinus densiflora and Quercus variabilis forests, which are the most dominant needleleaf and broadleaf forests in Korea, using the Korean Forest Soil Carbon (KFSC) model under the two climate change scenarios (2012-2100; Constant Temperature (CT) scenario and Representative Concentration Pathway (RCP) 8.5 scenario). To construct simulation unit, the forest land areas for those two species in the 5th National Forest Inventory (NFI) data were sorted by administrative district and stand age class. The C pools were initialized at 2012, and any disturbance was not considered during the simulation period. Although the forest C stocks of two species generally increased over time, the forest C stocks under the RCP 8.5 scenario were less than those stocks under the CT scenario. The C stocks of P. densiflora forests increased from 260.4 Tg C in 2012 to 395.3 (CT scenario) or 384.1 Tg C (RCP 8.5 scenario) in 2100. For Q. variabilis forests, the C stocks increased from 124.4 Tg C in 2012 to 219.5 (CT scenario) or 204.7 (RCP 8.5 scenario) Tg C in 2100. Compared to 5th NFI data, the initial value of C stocks in dead organic matter C pools seemed valid. Accordingly, the annual C sequestration rates of the two species over the simulation period under the RCP 8.5 scenario (65.8 and $164.2g\;C\;m^{-2}\;yr^{-1}$ for P. densiflora and Q. variabilis) were lower than those values under the CT scenario (71.1 and $193.5g\;C\;m^{-2}\;yr^{-1}$ for P. densiflora and Q. variabilis). We concluded that the C sequestration potential of P. densiflora and Q. variabilis forests could be decreased by climate change. Although there were uncertainties from parameters and model structure, this study could contribute to elucidating the C dynamics of South Korean forests in future.

Comparison of Two Methods of Recruiting the Acutely Injured Lung (급성 폐손상에서 폐를 Recruit시키는 방법간의 비교 연구)

  • Suh, Gee-Young;Kang, Kyeong-Woo;Park, Sang-Joon;Kim, Ho-Choel;Young, Lim-Si;Chung, Man-Pyo;Han, Jeong-Ho;Kim, Ho-Joong;Kwon, O-Jung;Rhee, Chong-H.
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.4
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    • pp.500-512
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    • 2000
  • Background : To evaluate the efficacy of two methods of obtaining lung recruitment to reduce ventilator-induced lung injury(VILI). Methods : Fifteen New-Zealand white rabbits were ventilated in the pressure-controlled mode while maintaining constant tidal volume(10 ml/kg) and fixed respiration rate. Lung injury was induced by repeated saline lavage (PaO2<100 mmHg), and the pressure-volume curve was drawn to obtain Pflex. The animals were then randomly assigned to three groups and ventilated for 4 hours. In the control group(n=5), positive end-expiratory pressure(PEEP) less than that of Pflex by 3 mmHg was applied throughout the study. In the recruitment maneuver(RM) group(n=5), RM(CPAP of 22.5 mmHg, for 45 seconds) was performed every 15 minutes in addition to PEEP level less than Pflex by 3 mmHg This phrase is unclear. In the Pflex group, PEEP of Pflex was given without RM. Gas exchange, lung mechanics, and hemodynamics parameters as well as pathology were examined. Results : 1) Both the control and RM groups showed decreasing tendency in PaO2 with time. There was significantly decreased PaO2 at 4 hr compared to Ihr(p<0.05). But in the Pflex group, PaO2 did not decrease with time(p<0.05 vs other groups at 3, 4 hr). PaCO2 did not show significant difference among the three groups. 2) There was no significant difference in static compliance and plateau pressure. Mean blood pressure and heart rate also did not show any significant difference among the three groups. 3) The pathologic exam showed significantly less neutrophil infiltration in the Pflex group than in the control group(p<0.05). There was borderline significant difference in hyaline membrane score among the groups (p= 0.0532). Conclusion : Although recruitment maneuver of the injured lung may be important in decreasing VILI, it alone may not be sufficient to minimize VILI.

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