• Tuberculosis and Respiratory Diseases
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• v.42 no.3
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• pp.351-360
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• 1995

Background: Pressure support(PS) is becomimg a widely accepted method of mechanical ventilation either for total unloading or for partial unloading of respiratory muscle. The aim of the study was to find out if PS exert different effects on respiratory mechanics in synchronized intermittent mandatory ventilation(SIMV) and continuous positive airway pressure (CPAP) modes. Methods: 5, 10 and 15 cm $H_2O$ of PS were sequentially applied in 14 patients($69{\pm}12$ yrs, M:F=9:5) and respiratory rate (RR), tidal volume($V_T$), work of breathing(WOB), pressure time product(PTP), $P_{0.1}$, and $T_1/T_{TOT}$ were measured using the CP-100 pulmonary monitor(Bicore, USA) in SIMV and CPAP modes respectively. Results: 1) Common effects of PS on respiratory mechanics in both CPAP and SIMV modes As the level of PS was increased(0, 5, 10, 15 cm $H_2O$), $V_T$ was increased in CPAP mode($0.28{\pm}0.09$, $0.29{\pm}0.09$, $0.31{\pm}0.11$, $0.34{\pm}0.12\;L$, respectively, p=0.001), and also in SIMV mode($0.31{\pm}0.15$, $0.32{\pm}0.09$, $0.34{\pm}0.16$, $0.36{\pm}0.15\;L$, respectively, p=0.0215). WOB was decreased in CPAP mode($1.40{\pm}1.02$, $1.01{\pm}0.80$, $0.80{\pm}0.85$, $0.68{\pm}0.76$ joule/L, respectively, p=0.0001), and in SIMV mode($0.97{\pm}0.77$, $0.76{\pm}0.64$, $0.57{\pm}0.55$, $0.49{\pm}0.49$ joule/L, respectively, p=0.0001). PTP was also decreased in CPAP mode($300{\pm}216$, $217{\pm}165$, $179{\pm}187$, $122{\pm}114cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0001), and in SIMV mode($218{\pm}181$, $178{\pm}157$, $130{\pm}147$, $108{\pm}129cm$ $H_2O{\cdot}sec/min$, respectively, p=0.0017). 2) Different effects of PS on respiratory mechanics in CP AP and SIMV modes By application of PS (0, 5, 10, 15 cm $H_2O$), RR was not changed in CPAP mode($27.9{\pm}6.7$, $30.0{\pm}6.6$, $26.1{\pm}9.1$, $27.5{\pm}5.7/min$, respectively, p=0.505), but it was decreased in SIMV mode ($27.4{\pm}5.1$, $27.8{\pm}6.5$, $27.6{\pm}6.2$, $25.1{\pm}5.4/min$, respectively, p=0.0001). $P_{0.1}$ was reduced in CPAP mode($6.2{\pm}3.5$, $4.8{\pm}2.8$, $4.8{\pm}3.8$, $3.9{\pm}2.5\;cm$ $H_2O$, respectively, p=0.0061), but not in SIMV mode($4.3{\pm}2.1$, $4.0{\pm}1.8$, $3.5{\pm}1.6$, $3.5{\pm}1.9\;cm$ $H_2O$, respectively, p=0.054). $T_1/T_{TOT}$ was decreased in CPAP mode($0.40{\pm}0.05$, $0.39{\pm}0.04$, $0.37{\pm}0.04$, $0.35{\pm}0.04$, respectively, p=0.0004), but not in SIMV mode($0.40{\pm}0.08$, $0.35{\pm}0.07$, $0.38{\pm}0.10$, $0.37{\pm}0.10$, respectively, p=0.287). 3) Comparison of respiratory mechanics between CPAP+PS and SIMV alone at same tidal volume. The tidal volume in CPAP+PS 10 cm $H_2O$ was comparable to that of SIMV alone. Under this condition, the RR($26.1{\pm}9.1$, $27.4{\pm}5.1/min$, respectively, p=0.516), WOB($0.80{\pm}0.85$, 0.97+0.77 joule/L, respectively, p=0.485), $P_{0.1}$($3.9{\pm}2.5$, $4.3{\pm}2.1\;cm$ $H_2O$, respectively, p=0.481) were not different between the two methods, but PTP($179{\pm}187$, $218{\pm}181 cmH_2O{\cdot}sec/min$, respectively, p=0.042) and $T_1/T_{TOT}$($0.37{\pm}0.04$, $0.40{\pm}0.08$, respectively, p=0.026) were significantly lower in CPAP+PS than in SIMV alone. Conclusion: PS up to 15 cm $H_2O$ increased tidal volume, decreased work of breathing and pressure time product in both SIMV and CPAP modes. PS decreased respiration rate in SIMV mode but not in CPAP mode, while it reduced central respiratory drive($P_{0.1}$) and shortened duty cycle ($T_1/T_{TOT}$) in CPAP mode but not in SIMV mode. By 10 em $H_2O$ of PS in CPAP mode, same tidal volume was obtained as in SIMV mode, and both methods were comparable in respect to RR, WOB, $P_{0.1}$, but CPAP+PS was superior in respect to the efficiency of the respiratory muscle work (PTP) and duty cycle($T_1/T_{TOT}$).

• Journal of Chest Surgery
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• v.32 no.7
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• pp.637-647
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• 1999

Background: Ischemia-reperfusion injury is one of the major contributing causes of early graft failure in lung transplantation. It has been suggested that triiodothyronine (T3) may ameliorate ischemia-reperfusion injury to various organs in vivo and in vitro. Predicting its beneficial effect for ischemic lung injury, we set out to demonstrate it by administering T3 into the in situ canine ischemia-reperfusion model. Material and Method: Sixteen adult mongrel dogs were randomly allocated into group A and B. T3 $(3.6\mug/kg)$ was administered before the initiation of single lung ischemia in group B, whereas the same amount of saline was administered in group A. Ischemia was induced in the left lung by clamping the left hilum for 100 minutes. After reperfusion, various hemodynamic parameters and blood gases were analyzed for 4 hours while intermittently clamping the right hilum in order to allow observation of the injured left lung function. Result: Arterial oxygen partial pressure $(PaO_2)$ decreased 30 minutes after reperfusion and recovered gradually thereafter in both groups. In group B the decrease of $PaO_2$ was less marked than in group A. The recovery of $PaO_2$ was faster in group B than in group A. The differences between the two groups were statistically significant from 30 minutes after reperfusion $(125\pm34$ mmHg and $252\pm44$ mmHg, p<0.05) until the end of the experiment $(178\pm42$mmHg and $330\pm37$ mmHg, p<0.05). The differences in the arterial carbon dioxide pressure, airway pressure and lung compliance showed no statistical significance. The malondialdehyde (MDA) level, measured from the tissue obtained 240 minutes after reperfusion, was lower in group B $(0.40\pm0.04\mu$M) than in group A $(0.53\pm0.05\mu$M, p<0.05). The ATP level of group B $(0.69\pm0.07\mu$M/g) was significantly higher than that of group A $(0.48\pm0.07\mu$M/g, p<0.05). The microscopic exami nation revealed varying degrees of injury such as perivascular neutrophil infiltration, capillary hemorrhage and interstitial congestion. There were no differences in the microscopic findings between the two groups. CONCLUSION T3 has beneficial effects on the ischemic canine lung injury including preservation of oxygenation capacity, less production of lipid peroxidation products and a higher level of tissue ATP. These results suggest that T3 is effective in pulmonary allograft preservation.

• Clinical and Experimental Pediatrics
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• v.46 no.8
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• pp.777-783
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• 2003

Purpose : The aim of this study was to evaluate the effect of inhaled nitric oxide(iNO) on gas exchange, hemodynamics and pulmonary inflammation in newborn piglets with E. coli induced septic lung. Methods : Twenty three instrumented and ventilated piglets were randomized into three groups : CON(n=6), PCON(n=9), and PNO(n=8). In the piglets of the PCON and PNO groups, E. coli septic lung was induced by endotracheal instillation of E. coli. Ten ppm iNO was given continuously in the PNO group after endotracheal instillation of E. coli. All animals were mechanically ventilated for six hour with a peak inspiratory pressure of 30 $cmH_2O$, frequency of 25 breaths/min, $FiO_2$ 1.0 and a positive end-expiratory pressure of 4 $cmH_2O$. All measurements were made at one hour intervals during the experiment. At the end of the experiment, lung tissue was harvested for the analysis of myeloperoxidase activity, indicative of lung inflammation. Results : All piglets with pulmonary instillation of E. coli developed E. coli sepsis. Piglets in the PCON group developed progresseve pulmonry hypertension, hypoxemia and hypercarbia compared to the CON group due to increased pulmonary vascular resistance, intrapulmonary shunt fraction and physiologic dead space fraction. iNO did not reverse pulmonary hypertension in the PNO group. However iNO significantly improved oxygenation, which was attributed to marked improvement of venous admixture and partial attenuation of increase in dead space fraction. Increased myeloperoxidase activity in PCON compared to CON was significantly attenuated in PNO. Conclusion : iNO improves oxygenation and lung inflammation in newborn piglets with E. coli induced septic lung.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.1
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• pp.1-10
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• 2020

The atomic structures of silicate liquids at high pressure provide insights into the transport properties including thermal conductivities or elemental partitioning behavior between rocks and magmas in Earth's interior. Whereas the local electronic structure around silicon may vary with the arrangement of the nearby oxygens, the detailed nature of such relationship remains to be established. Here, we explored the atomic origin of the pressure-induced changes in the electronic structure around silicon by calculating the partial electronic density of states and L₃-edge X-ray absorption spectra of SiO₂ polymorphs. The result showed that the Si PDOS at the conduction band varies with the crystal structure and local atomic environments. Particularly, d-orbital showed the distinct features at 108 and 130 eV upon the changes in the coordination number of Si. Calculated Si XAS spectra showed features due to the s,d-orbitals at the conduction band and varied similarly with those observed in s,d-orbitals upon changes in the crystal structures. The calculated Si XAS spectrum for α-quartz was analogous to the experimental Si XRS spectrum for SiO₂ glass, implying the overall similarities in the local atomic environments around the Si. The edge energies at the center of gravity of XAS spectra were closely related to the Si-O distance, thus showing the systematic changes upon densification. Current results suggest that the Si L_2,3-edge XRS, sensitive probe of the Si-O distance, would be useful in unveiling the densification mechanism of silicate glasses and melts at high pressure.

• Journal of Veterinary Clinics
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• v.32 no.4
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• pp.308-312
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• 2015

This study was aimed to evaluate the effects of tramadol hydrochloride on the minimum alveolar concentration of isoflurane ($MAC_{ISO}$) in dogs. Six healthy, female German shepherd dogs (aged 1-2 years) were used in this study. Anesthesia was induced by mask induction and maintained with isoflurane in oxygen. Mechanical ventilation maintained the end-tidal $CO_2$ partial pressure ($P_{ET}CO_2$) from 35 to 45 mmHg throughout the study. A baseline $MAC_{ISO}$ ($MAC_{ISO}B$) was determined starting 45 minutes after induction of anesthesia by clamping a pedal digit until gross purposeful movement was detected. After $MAC_{ISO}B$ determination, dogs received a tramadol loading dose of 3 mg/kg followed by a continuous rate infusion (CRI) of 2.6 mg/kg/h. The determination of $MAC_{ISO}$ after administration of tramadol ($MAC_{ISO}T$) began 20 min after the start of the CRI. Arterial blood pressure and heart rate were recorded continuously and arterial blood samples for blood gas analysis were collected at the end of the equilibration period. Mean ${\pm}$ SD values for the $MAC_{ISO}B$ and $MAC_{ISO}T$ were $1.33{\pm}0.04%$ and $1.23{\pm}0.04%$, respectively. The $MAC_{ISO}B$ decreased significantly by $7.5{\pm}0.2%$ (P < 0.05) after administration of tramadol. The mean heart rate and arterial blood pressure of six dogs were not changed significantly after tramadol administration. The blood gas levels remained constant during the study. In conclusion, tramadol could significantly reduce $MAC_{ISO}$ without depression of cardiorespiratory function. Thus, the use of tramadol on inhalation anesthesia with isoflurane in dogs can improve the stability of anesthesia and the quality of recovery.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.2
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• pp.43-49
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• 2019

Purpose: This study examined changes in the position of the heat and lungs depending on the patient's breathing method during left breast cancer radiotherapy and used treatment plans to compare the resulting radiation dose. Materials and methods: The participants consisted of 10 patients with left breast cancer. A CT simulator(SIMENS SOMATOM AS, Germany) was used to obtain images when using three different breathing methods: free breathing(FB), deep inspiration breath hold(DIBH with Abches, DIBH), inspiration breath hold(IBH with CPAP, CPAP). A Ray Station(5.0.2.35, Sweden) was used for treatment planning, the treatment method was volumetric modulated arc therapy (VMAT) with one partial arc of the same angle, and the prescribed dose to the planning target volume (PTV) was a total dose of 50Gy(2Gy/day). In treatment plan analysis, the 95% dose (D95) to the PTV, the conformity index(CI), and the homogeneity index (HI) were compared. The lungs, heart, and left anterior descending artery (LAD) were selected as the organs at risk(OARs). Results: The mean volume of the ipsilateral lung for FB, DIBH, and CPAP was 1245.58±301.31㎤, 1790.09±362.43 ㎤, 1775.44±476.71 ㎤. The mean D95 for the PTV was 46.67±1.89Gy, 46.85±1.72Gy, 46.97±23.4Gy, and the mean CI and HI were 0.95±0.02, 0.96±0.02, 0.95±0.02 and 0.91±0.01, 0.90±0.01, 0.92±0.02. The V20 of Whole Lung was 10.74±4.50%, 8.29±3.14%, 9.12±3.29% and The V20 of the ipsilateral lung was 20.45±8.65%, 17.18±7.04%, 18.85±7.85%, the Dmean of the heart was 7.82±1.27Gy, 6.10±1.27Gy, 5.67±1.56Gy, and the Dmax of the LAD was 20.41±7.56Gy, 14.88±3.57Gy, 14.96±2.81Gy. The distance from the thoracic wall to the LAD was measured to be 11.33±4.70mm, 22.40±6.01mm, 20.14±6.23mm. Conclusion: During left breast cancer radiotherapy, the lung volume was 46.24% larger for DIBH than for FB, and 43.11% larger for CPAP than FB. The larger lung volume increases the distance between the thoracic wall and the heart. In this way, the LAD, which is one of the nearby OARs, can be more effectively protected while still satisfying the treatment plan. The lung volume was largest for DIBH, and the distance between the LAD and thoracic wall was also the greatest. However, when performing treatment with DIBH, the intra-fraction error cannot be ignored. Moreover, communication between the patient and the radiotherapist is also an important factor in DIBH treatment. When communication is problematic, or if the patient has difficulty holding their breath, we believe that CPAP could be used as an alternative to DIBH. In order to verify the clinical efficacy of CPAP, it will be necessary to perform long-term follow-up of a greater number of patients.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.577-584
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• 2018

This study was conducted to investigate the potential of chicken feather (CF), which is a by-product in poultry industry, as a partial substitute of wood fiber in the production of wood-based fiberboard. Keratin-type protein constituted the majority of CF, and its appearance did not differ from that of wood fiber. When the formaldehyde (HCHO) adsorptivities of CF compared by its pretreatment type, feather meal (FM), which was pretreated CF with high temperature and pressure and then grounded, showed the highest HCHO adsorptivity. In addition, there was no difference between the adsorbed HCHO amounts, which was measured by dinitrophenylhydrazine method, of scissors-chopped CF and CF beated with an electrical blender. Mechanical properties and HCHO emission of medium-density fiberboards (MDF), which were fabricated with wood fiber and 5 wt% CF, beated CF or FM based on the oven-dried weight of wood fiber, were not influenced by the pretreatment type of CF. However, when the values compared with those of MDF made with just wood fiber, thickness swelling and HCHO emission of the MDF were improved greatly with the addition of CF, beated CF or FM. Based on the results, it might be possible to produce MDF with improved dimensional stability and low HCHO emission if CF, beated CF or FM is added partially as a substitute of wood fiber in the manufacturing process of MDF produced with the conventional urea-formaldehyde resin of $E_1$ grade. However, the use of CF or FM in the production of MDF has a low economic feasibility at the current situation due to the securing difficulty and high cost of CF. In order to enhance the economic feasibility, it requires to use CF produced at small to medium-sized chicken meat plants. More importantly, it is considered that the technology developed from this research has a great potential to make provision for the prohibition of animal-based feed and to dispose environmentally avian influenza-infected poultry.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.814-820
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• 2014

In this work, hydrate inhibition performance of water-soluble polymers including pyrrolidone, caprolactam, acrylamide types were evaluated using torque measurement and high pressure differential scanning calorimeter (HP ${\mu}$-DSC). The obtained experimental results suggest that the studied polymers represent the kinetic hydrate inhibition (KHI) performance. 0.5 wt% polyvinylcaprolactam (PVCap) solution shows the hydrate onset time of 34.4 min and subcooling temperature of 15.9 K, which is better KHI performance than that of pure water - hydrate onset time of 12.3 min and subcooling temperature of 6.0 K. 0.5 wt% polyvinylpyrrolidone (PVP) solution shows the hydrate onset time of 27.6 min and the subcooling temperature of 13.2 K while polyacrylamide-co-acrylic acid partial sodium salt (PAM-co-AA) solution shows less KHI performance than PVP solution at both 0.5 and 5.0 wt%. However, PAM-co-AA solution shows slow growth rate and low hydrate amount than PVCap. In addition to hydrate onset and growth condition, torque change with time was investigated as one of KHI evaluation methods. 0.5 wt% PVCap solution shows the lowest average torque of 6.4 N cm and 0.5 wt% PAM-co-AA solution shows the average torque of 7.2 N cm. For 0.5 wt% PVP solution, it increases 11.5 N cm and 5.0 wt% PAM-co-AA solution shows the maximum average torque of 13.4 N cm, which is similar to the average torque of pure water, 15.2 N cm. Judging from the experimental results obtained by both an autoclave and a HP ${\mu}$-DSC, the PVCap solution shows the best performance among the KHIs in terms of delaying hydrate nucleation. From these results, it can be concluded that the torque change with time is useful to identify the flow ability of tested solution, and the further research on the inhibition of hydrate formation can be approached in various aspects using a HP ${\mu}$-DSC.

• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.66-72
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• 2009

The detection methods are required to monitor and diagnose the abnormality on the insulation condition inside a gas-insulated switchgear (GIS). Due to a good sensitivity to the products decomposed by partial discharges (PDs) in $SF_6$ gas, the development of a SWNT gas sensor is actively in progress. However, a few numerical studies on the diffusion mechanism of the $SF_6$ decomposition products by PD have been reported. In this study, we modeled $SF_6$ decomposition process in a chamber by calculating temperature, pressure and concentration of the decomposition products by using a commercial CFD program in conjunction with experimental data. It was assumed that the mass production rate and the generation temperature of the decomposition products were $5.04{\times}10^{-10}$ [g/s] and over 773 K respectively. To calculate the concentration equation, the Schmidt number was specified to get the diffusion coefficient functioned by viscosity and density of $SF_6$ gas instead rather than setting it directly. The results showed that the drive potential is governed mainly by the gradient of the decomposition concentration. A lower concentration of the decomposition products was observed as the sensors were placed more away from the discharge region. Also, the concentration increased by increasing the discharge time. By installing multiple sensors the location of PD is expected to be identified by monitoring the response time of the sensors, and the information should be very useful for the diagnosis and maintenance of GIS.

• Journal of the Korean Vacuum Society
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• v.18 no.2
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• pp.133-140
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• 2009

$Ta_{2}O_{5}$ thin films were deposited by RF magnetron sputtering method under various RF power, substrates and oxygen partial pressure. Elliptic constants were measured by using a phase modulated spectroscopic ellipsometer and analyzed with the Tauc-Lorentz dispersion formula and best fit method in the range of 310$\sim$1239 nm. Also, transmittance spectra of the films were measured by UV -Vis spectrophotometer in the range of 300$\sim$1000 nm. From these data, thickness of $Ta_{2}O_{5}$ and surface layer were analyzed and changes of magnitude and shape of dispersion of optical constants according to fabricated conditions were measured. Also, to evaluate thickness and optical constants data analyzed by Tauc-Lorentz dispersion formula, the measured and analyzed transmittance spectra were compared. In result of the comparison, two spectra were in good agreement each other. Accordingly, it indicates that our ellipsometric analysis is valid.