• Tuberculosis and Respiratory Diseases
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• v.50 no.5
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• pp.540-548
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• 2001

Backgrounds : Because ventilator-induced lung injury is partly dependent on the intensity of vascular flow, we hypothesized that hypothermia may attenuate the degree of such an injury through a reduced cardiac output. Methods : Twenty-seven male Sprague-Dawley rats were randomly assigned to normothermia ($37{\pm}1^{\circ}C$)-injurious ventilation (NT-V) group (n=10), hypothermia ($27{\pm}1^{\circ}C$)-injurious ventilation (HT-V) group (n=10), or nonventilated control group (n=7). The two thermal groups were subjected to injurious mechanical ventilation for 20 min with peak airway pressure 30 cm $H_2O$ at zero positive end-expiratory pressure, which was translated to tidal volume $54{\pm}6\;ml$ in the NT-V group and $53{\pm}4\;ml$ in the HT-V group (p>0.05). Results : Pressure-volume (P-V) curve after the injurious ventilation was almost identical to the baseline P-V curve in the HT-V group, whereas it was shifted rightward in the NT-V group. On gross inspection, the lungs of the HT-V group appeared smaller in size, and showed less hemorrhage especially at the dependent regions, than the lungs of the NT-V group. [Wet lung weight (g)/body weight (kg)] ($1.6{\pm}0.1$ vs $2.4{\pm}1.2$ ; p=0.014) and [wet lung weight/dry lung weight] ($5.0{\pm}0.1$ vs $6.1{\pm}0.8$ ; p=0.046) of the HT-V group were both lower than those of the NT-V group, while not different from those of the control group($1.4{\pm}0.4$, $4.8{\pm}0.4$, respectively). Protein concentration of the BAL fluid of the HT-V group was lower than that of the NT-V group($1,374{\pm}726\;ug/ml$ vs $3,471{\pm}1,985\;ug/ml$;p=0.003). Lactic dehydrogenase level of the BAL fluid of the HT-V group was lower than that of the NT-V group ($0.18{\pm}0.10\;unit/ml$ vs $0.43{\pm}0.22\;unit/ml$;p=0.046). Conclusions : Hypothermia attenuated pulmonary hemorrhage, permeability pulmonary edema, and alveolar cellular injuries associated with injurious mechanical ventilation, and preserved normal P-V characteristics of the lung in rats.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.169-175
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• 1998

Background: Heliox is known to decrease $PaCO_2$ in patients with increased airway resistance by increasing minute ventilation and reducing work of breathing(WOB). Besides these effect, heliox is expected to decrease functional anatomic dead space owing to improvement of peak expiratory flow rate(PEFR) and enhancement of gas distribution. We investigated whether heliox can decrease $PaCO_2$ even at the same minute ventilation (VE) and WOB with $N_2-O_2$ to speculate the effect of the heliox on the anatomic dead space. Material and Method: The subjects were 8 mechanically ventilated patients with asthma or upper airway obstruction(M : F=5 : 3, $68{\pm}10$years) who were under neuromuscular paralysis. The study was consisted of three 15-minutes phases: basal $N_2-O_2$ heliox and washout Heliox was administered via the low pressure inlet of servo 900C, and respiratory parameters were measured by pulmonary monitor(CP-100 pulmonary monitor, Bicore, Irvine, CA, USA). To obtain the same tidal volume(Vt) in heliox phase, the Vt on monitor was adjusted by the factor of relative flow rate of heliox to $N_2-O_2$. Dead space was calculated by Bohr equation. Results: 1) Vt, VE, peak inspiratory pressure(PIP) and peak inspiratory flow rate(PIFR) were not different between $N_2-O_2$ and heliox. 2) PEFR was higher on heliox($0.52{\pm}0.19$L/sec) than $N_2-O_2$($0.44{\pm}0.13$L/sec)(p=0.024). 3) $PaCO_2$(mmHg) were decreased with heliox($56.1{\pm}14.1$) compared to $N_2-O_2$($60.5{\pm}15.9$)(p=0.027). 4) Dead space ventilation(%) were decreased with heliox($73{\pm}9$ with $N_2-O_2$ and $71{\pm}10$ with heliox)(p=0.026). Conclusion: Heliox decreased $PaCO_2$ even at the same VE and WOB with $N_2-O_2$, and the effect was considered to be related with the reduction of anatomic dead space.

• Korean Journal of Agricultural Science
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• v.26 no.2
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• pp.77-93
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• 1999

This study is aiming at identifying the foreward and backward lingkage effects of the farm land base development project. Korean Government has continuously carried out farmland base development projets including the integrated agricultural development projects. large and medium scale irrigation projects and the comprehensive development of the four big river basin including tidal land reclamation and estuary dam construction for the all weather farming since 1962. the starting year of the five year economic development plans. Consequently the irrigation rate of paddy fields in Korea reached to 75% in 1998 and to escalate the irrigation rate, the Government had procured heavy investment fund from IBRD. IMF and OECF etc. To cope with the agricultural problems like trade liberalization in accordance with WTO policy, the government has tried to solve such problems as new farmland base development policy, preservation of the farmland and expansion of farmland to meet self-sufficiency of foods in the future. Especially, farmland base development projects have been challanged to environmental and ecological problems in evaluating economic benefits and costs where the value of non-market goods have not been included in those. Up to data, in evaluating benefits and costs of the projects, farmland base development projects have been confined to direct incremental value of farm products and it's related costs. Therefore the projects'efficiency as a decision making criteria has shown the low level of economic efficiencies. In estimating economic efficiencies including Leontiefs input-output analysis of the projects could not be founded in Korea at present. Accordingly this study is aimed at achieving and identifying the following objectives. (1) To identify the problems related to the financial supports of the Government in implementing the proposed projects. (2) To estimated backward and foreward linkage effects of the proposed project from the view point of national economy as a whole. To achieve the objectives, Hwangrak benefited area with reservoir which is located in Seosan-haemi Disticts, Chungnam Province were selected as a case study. The main results of the study are summarized as follows : a. The present value of investment and O & M cost were amounted to 3,510million won and the present value of the value added in related industries was estimated at 5.913million won for the period of economic life of 70 years. b. The total discounted value of farm products in the concerned industries derived by the project was estimated at 10,495million won and the foreward and backward linkage effects of the project were amounted to 6,760 and 5,126million won respectively. c. The total number of employment opportunities derived from the related industries for the period of project life were 3,136 man/year. d. Farmland base development projects were showed that the backward linkage effects estimated by index of the sensitivity dispersion were larger than the forward linkage effect estimated by index of the power of dispersion. On the other hand, the forward linkage effect of rice production value during project life was larger than the backward linkage effect e. The rate of creation of new job opportunity by means of implementing civil engineering works were shown high in itself rather than any other fields. and the linkage effects of production of the project investment were mainly derived from the metal and non-metal fields. f. According to the industrial linkage effect analysis, farmland base development projects were identified economically feasible from the view point of national economy as a whole even though the economic efficiencies of the project was outstandingly decreased owing to delaying construction period and increasing project costs.

• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.683-693
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• 1993

Background: During movement the major inputs to nervous system come from firstly the muscle and joint to maintain posture and motion and secondly the chemoreceptors and baroreceptors to adjust the cardiovascular and respiratory function. Their complex relationships are generally studied for many years but the direct relation between the joint and respiratory system is not studied thoroughly until now. So this experiment was performed to determine whether the natural movement of knee joint can cause the enhancement of respiratory function by observation of the changes of respiratory rate, phrenic nerve activity and inspiratory neuron activity during the stimulation of knee joint in cat anesthetized with $\alpha$-chloralose. Method: Twenty six male adult cats were used and the extracelluar recording using bipolar platinum electrode and carbon filament electrode was done to record the changes in the activities of phrenic nerve and inspiratory neuron movement of knee joint, injection of chemicals into the joint cavity and electrical stimulation of articular nerve were done. Results: The 60 Hz. could not but 120 Hz. flexion-extension movement of knee joint increased respiratory rate(R.R.), tidal neural activity(TNA) and minute neural activity(MNA). Intra-articular injection of lactate could not increase R.R. but significantly increase TNA and MNA which represented the enhanced respiratory function. Injection of potassium chloride showed similar effects with the case of lactate but the duration of effect was shorter. The electrical stimulation of medial articular nerve with IV strength which could activate only group I and II afferents showed increased TNA and MNA during stimulation but 20 V stimulation which could activate all the afferents increased all the respiratory parameters. The changes of inspiratory neuron activity by knee joint stimulation was similar to that of phrenic nerve. Conclusion: The respiratory center could be directly stimulated by the activation of group I and II articular afferents and it seemed that the magnitude of the respiratory center enhancement is proportional to the amount of sensory information from the knee joint. These facts might suggest that the respiratory function could be enhanced even by the normal movement of knee joint.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1022-1030
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• 1998

Background : In volume-controlled ventilation, the use of inspiratory pause increases the inspiratory time and thus increases mean airway pressure and improves ventilation. But under the same I : E ratio, the effects of inspiratory pause on mean airway pressure and gas exchange are not certain. Moreover, the effects may be different according to the resistance of respiratory system. So we studied the effects of inspiratory pause on airway pressure and gas exchange under the same I : E ratio in volume-controlled ventilation. Methods: Airway pressure and arterial blood gases were evaluated in 12 patients under volume-controlled mechanical ventilation with and without inspiratory pause time 5%. The I : E ratio of 1 : 3, $FiO_2$, tidal volume, respiratory rate, and PEEP were kept constant. Results: $PaCO_2$ with inspiratory pause was lower than without inspiratory pause ($38.6{\pm}7.4$ mmHg vs. $41.0{\pm}7.7$ mmHg. p<0.01). P(A-a)$O_2$ was not different between ventilation with and without inspiratory pause $185.3{\pm}86.5$ mmHg vs. $184.9{\pm}84.9$ mmHg, p=0.766). Mean airway pressure with inspiratory pause was higher than without inspiratory pause ($9.7{\pm}4.0\;cmH_2O$ vs. $8.8{\pm}4.0\;cmH_2O$, p<0.01). The resistance of respiratory system inversely correlated with the pressure difference between plateau pressure with pause and peak inspiratory pressure without pause (r=-0.777, p<0.l), but positively correlated with the pressure difference between peak inspiratory pressure with pause and peak inspiratory pressure without pause (r=0.811, p<0.01). Thus the amount of increase in mean airway pressure with pause positively correlated with the resistance of respiratory system (r=0.681, p<0.05). However, the change of mean airway pressure did not correlated with the change of $PaCO_2$. Conclusion: In volume-controlled ventilation under the same I : E ratio of 1 : 3, inspiratory pause time of 5% increases mean airway pressure and improves ventilation. Although the higher resistance of respiratory system, the more increased mean airway pressure, the increase in mean airway pressure did not correlated with the change in $PaCO_2$.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.574-582
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• 1997

Background : Normal humans meet the increased ventilatory need during exercise initially by the increase of tidal volume (TV) and later by the increase of respiratory frequency (Rf). And the inspiratory duty cycle (Ti/Ttot) is also increased more than 50% for the compensation of the decrease of respiratory cycle provoked by the increase of respiratory frequency. The patients with chronic airflow obstruction show rapid and shallow breathing pattern during exercise because of the decreased ventilatory capacity and the increased dead space ventilation. However, the studies about the change of inspiratory duty cycle are only a few and there is no literature about the relationship between the change of inspiratory duty cycle and the degree of airflow obstruction. Methods : The subjects were the twelve patients with chronic airflow obstruction (CAO) and ten normal people. The incremental exercise test was done. The increase of work load was 10 W in CAO group and 25 W in normal control group. The analysis of the results was done by the comparison of the parameters such as minute ventilation (VE), TV, Rf, physiologic dead space (Vd/Vt), and inspiratory duty cycle between the two groups. Each parameters were compared after transformation into % control duration base that means dividing the total exercise time into five fractions and % control duration data were obtained at rest, 20%, 40%, 60%, 80%, and max. Statistical analysis was done by repeated measure ANOVA using SAS program. Results : The changes of VE and TV were significantly different between two groups while the change of Rf was not significant. The decrease of Vd/Vt was significantly low in CAO group. Ti/Ttot was markedly increased from 38.4 + 3.0% at rest to 48.6 + 4.5% at max in normal control group while Ti/Ttot showed little change from 40.5 + 2.2% at rest to 42.6 + 3.5% at max. And the change of inspiratory duty cycle showed highly good correlation with the degree of airflow obstruction (FEV1%). (r=0.8151, p < 0.05). Conclusions : The increase of Ti/Ttot during exercise observed in normal humans is absent in the patients with CAO and the change of Ti/Ttot is well correlated with the degree of airflow obstruction.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.416-426
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• 2005

Intravenous sedation have many advantages of rapid onset and recovery, ability of control sedation levels and duration through titration. Midazolam is most commonly used intravenous medication for sedation in pediatrics, endoscopy, oncologic procedures and so on. But in dentistry, midazolam intravenous sedation is usually for adult, and there are few reports for children. Todays, children who need sedation become more and older, intravenous sedation technique is going a matter of concern in pediatric dentistry. The purpose of this paper is to evaluate the efficacy of sedation and clinical success for different initial dosage of midazolam in intravenous sedation for pediatric dental patients. 16 healthy children (male 10, female 6), mean age $54.7{\pm}10.7$ months, who needed at least two separate treatment visits requiring local anesthesia were chosen for this study. Every children were taken 0.3mg/kg, maximum 5mg of midazolam by intramuscular route, and then 30~50% $N_2O-O_2$ for 10 minutes was given. On every visits, one of the following 2 different initial dosage was given by intravenous route : (1) Group I : 0.1mg/kg Midazolam (2) Group II : 0.2mg/kg Midazolam. Additional dosage was half of the first dose. Physiologic parameters (oxygen saturation, heart rate, respiratory rate, end-tidal carbon dioxide pressure) was recorded by ten procedure steps. Behavior was videotaped and rated using Ohio State University Behavioral Rating Scale and Automated Counting System by one investigator, blind to administered dosage. After the treatment, operator evaluated the clinical success. Physiologic parameters were stable and within normal range during treatment in both groups. The analyzed sedative effect, in behavioral evaluation, ratio of favorable Quiet was higher in group II, and clinical success rate of group II was better than group I. Induction time was rapid in group II, and recovery time was rapid in group I. And there was no statistically difference between two groups in every results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.397-402
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• 2005

In the Korean seas, Sea Surface Temperature (SST) and Thermal Fronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST As the result of EOF method applying SST, the variance of the 1st mode was 97.6%. It is suitable to explain SST conditions in the whole Korean seas. Time coefficients were shown annual variations and spatial distributions were shown the closer to the continent the higher SST variations like as annual amplitudes. The 2nd mode presented higher time coefficients of 1993, 94, and 95 than those of other years. Although the influence is a little, that tan explain EININO effort to the Korean seas. TF were detected by Sobel Edge Detection Method using gradient of SST. Consequently, TF were divided into 4 fronts; the Subpolar Front (SPF) dividing into the north and south part of the East sea , the Kuroshio Front (KF) in the East China Sea (ESC), the South Sea Coastal Front (SSCF) in the South sea, and the Tidal Front in the West sea. TF located in steep slope of submarine topography. The distributions of 1st mode in SST were bounded in the same place, and these results should be considered to influence of seasonal variations. To discover temporal and spatial variations of TF, SST gradient values were analyzed by EOF. The time coefficients fo the 1st mode (variance : 64.55%) showed distinctive annual variations and SPF, KF, and SSCF was significantly appeared in March. the spatial distributions of the 2nd mode showed contrast distribution, as SPF and SSCF had strong'-'value, where KF had strong'+'value. The time of'+'and'-'value was May and October, respectively. Time coefficients of the 3rd mode had 2 peaks per year and showed definite seasonal variations. SPF represented striking'+'value which time was March and October. That was result reflected time of the 1st and 2nd mode. We can suggest specific temporal and spatial variations of TF using EOF.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.10-27
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• 2017

Recently, the importance of recognizing the natural environment and the need for its conservation are increasing due to rapid urbanization. Suncheon Bay, designated as Scenic Site No. 41 and one of the World's Five Greatest Coastal Wetlands, is the only tideland among the tidal flats in Korea, which has salt marsh reserves. It has high conservation value from the ecological aspect. In addition to the Suncheon Bay National Garden, it provides various benefits not only to visitors but to local residents as well in terms of economics, environmental issues, and history and cultural aspects. Two million tourists visit the site annually, which has constantly highlighted the limits of ecological capacity. The valuation of the Suncheon Bay wetland is more important for the sustainability of the Suncheon Bay wetland than for its value as a tourism resource for the activation of the local economy. This study used the Logit model, which is commonly used among probabilistic choice models, to evaluate the economic value of Suncheon Bay wetland with the contingent valuation method(CVM). Applying the conservation value of the Suncheon Bay wetland to the benefit of KRW 8,200 for 1 person and 1 day, the benefit from exploration is KRW 2,050, the management and conservation value is KRW 3,034, and the heritage value is KRW 3,116. The results of this study are that benefit from the annual exploration of Suncheon Bay wetland was KRW 44.3 in billion, the management and conservation value was KRW 6.55 in billion, and the heritage value was KRW 6.73 in billion. When converted to the number of paying visitors per year, the conservation value is about KRW 177.1 billion. This study was conducted to evaluate the use and conservation aspects of the economic value of Suncheon Bay wetland. Based on the latent value of the Suncheon Bay wetland, it provides basic data about the efficient management and policy establishment of Suncheon Bay wetland. The study is significant in that the ecological sustainability of the Suncheon bay wetland and the value of non-marketable were evaluated based on the recognition of 'benefit through exploration', 'management and conservation value' and 'value of heritage'. It can be used as policy decision data on the integrated collection of the admission fee of the Suncheon Bay wetland and Suncheon Bay National Garden.

• The Korean Journal of Physiology
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• v.1 no.2
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• pp.199-213
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• 1967

Circulatory and respiratory activities were observed in men exposed to the environment of engine room of a cruising Republic of Korea Navy ship and compared to the control values obtained in an ordinary laboratory room on land. The environment of an engine room of cruising navy ship was presumed to be a multiple stress acting on men. The environment of the engine room included high temperature $(35-42^{\circ}C)$, low relative humidity (20-38% saturation), vibration (about 7 cycles per second), rolling and pitching of ship and noises. Sixteen men were divided into two groups consisted of each 8 subjects. Subjects of sea duty group had experience of continuous on board duty averaging 3.5 years. Men of land duty group had no experience of on board activity. On land observations were made on one day prior to the boarding and leaving the port and four days after landing. In between observations in the engine room were made on the first, 5 th, 9 th, 12 th, and 14 th day of on board activity. The whole experimental period lasted for 20 days. Measurements on circulatory and respiratory parameters were at standing resting state (after 30 minutes standing in the case of on land study and 15 minutes in engine room study) and within one minute after cessation of on the spot running of which rhythm was 30/min. and lasted for 5 minutes. Oxygen consumption and pulmonary function test were done in the period of two minutes from the 3rd to 5th minutes of running. The following results were obtained. 1. Body temperature showed no change regardless of group difference or on land or on board measurements. 2. Pulse rate increased markedly after boarding the ship id both groups. Pulse rate increased from the first day on board at rest and after exercise as compared to the on land control value. This increase in pulse rate was more marked after exercise. Sea duty group showed less increase in pulse rate at rest than the land duty group. Standing and resting pulse rate of sea duty group on lam was 81 and increased to 87 at the 5th day on board and remained smaller than the land duty group throughout the period on board. Control standing and resting pulse rate of land duty group on land was 76 and reached 89 at the 9th day on board and thereafter decreased a little. Pulse rate of land duty group at rest on board remained greater than that of sea duty group throughout the period on board. 3. Systolic blood pressure of sea duty group increased after boarding the ship and remained higher than the control value on land. In the land duty group, however, systolic blood pressure decreased during the period on board the ship. Diastolic blood pressure decreased in both groups. 4. Resting breathing rate of land duty group increased and remained higher than the control value on land. In sea duty group, however, resting breathing rate showed a transient increase on the 1st day on board and decreased thereafter to the control value on land and kept the same level throughout the period of cruise. Absolute value of breathing rate in the sea duty group was greater than the land duty group both at rest and after exercise. 5. There was a lowering of breathing efficiency in both groups. Thus, increases in tidal volume and minute ventilation volume and decreases in maximum breathing capacity, vital capacity, capacity ratio and air velocity Index were observed after boarding the ship. An increase in ventilation equivalent was also observed in both groups. The lowering of breathing efficiency was more marked in the land duty group than the sea duty group. 6. Energy expediture increased in both groups during their stay on the ship and was more marked in the sea duty group. 7, Lactate concentration in venous blood at rest and after exercise increased after boarding the ship and no group difference was observed.