• Analytical Science and Technology
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• v.26 no.1
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• pp.51-60
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• 2013

The geometrical parameters, vibrational frequencies, and adiabatic electron affinities (AEAs) for c-$C_nF_{2n}$ (n=8, 9) and $C_{10}F_{18}$ (perfluorodecalin) have been investigated using various quantum mechanical techniques. The possible structures for the neutrals and anions of c-PFA are fully optimized and electron affinities are predicted using energy difference between the neutral and anion. The harmonic vibrational frequencies are also determined and zero-point vibrational energies (ZPVEs) are considered for the better prediction of the electron affinities. The electron affinities are predicted to be 1.18 eV for c-$C_8F_{16}$ (ortho), 1.37 eV for c-$C_9F_{18}$, and 1.38 eV for $C_{10}F_{18}$ (perfluorodecalin) at the MP2 level of theory after ZPVE correction.

• Tuberculosis and Respiratory Diseases
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• v.48 no.2
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• pp.223-235
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• 2000

Background: Liquid ventilation is associated with decreased inflammatory response in an injured lung. This study was performed to investigate if whether perfluorocarbon(PFC) can decrease chemokine expression in airway epithelial cells. Methods: A549 cells were used for airway epithelial cells and perfluorodecalin for PFC. To expose cells to PFC, lower chamber of Transwell$^{(R)}$plate was used. This study was performed in two parts. In the first part, we examined whether PFC could decrease chemokine expression in airway epithelial cells through inhibition of other inflammatory cells. Peripheral blood mononuclear cells(PBMC's) were isolated and stimulated with lipopolysaccharide(LPS, 10 ${\mu}g/mL$) for 24 hours with or without exposure to PFC. Then A549 cells were stimulated with conditioned media(CM) containing the culture supernatants of PBMC. After 24 hours, the expressions of interleukin-8(IL-8) and RANTES were measured. In the second part of the study, we studied whether PFC could directly suppress chemokine expression in airway epithelial cells. A549 cells were stimulated for 24 hours with interleukin-l$\beta$ and/or tumor necrosis factor-$\alpha$ with or without exposure to PFC, and then the chemokine expression was measured. Northern analysis was used to measure the mRNA expression, and ELISA was used for immunoreactive protein measurements in culture supernatant. Results: 1. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by CM from LPS-stimulated PBMC in A459 cells compared to with CM from unstimulated PBCM (p<0.05), but exposure of PFC had no significant effect on either mRNA expression or immunoreactive protein expression. 2. IL-8 and RANTES mRNA expression and immunoreactive protein production were increased significantly by IL-1$\beta$ and TNF-$\alpha$ in A549 cells(p<0.05), but exposure of PFC had no significant effect on neither either mRNA expression nor immunoreactive protein production. Conclusion : Decreased chemokine expression of airway epithelial cells may not be involved in decreased inflammatory response observed in liquid ventilation. Further studies on possible mechanisms of decreased inflammatory response are warranted.

• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.14-23
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• 2002

Background: The opitmal ventilator setting during partial liquid ventilation(PLV) is controversial. This study investigated the effects of various gas exchange parameters during PLV in normal rabbit lungs in order to aid in the development of an optimal ventilator setting during PLV. Methods: Seven New-Zealand white rabbits were ventilated in pressure-controlled mode with the following settings; tidal volume($V_T$) 8 mL/kg, positive end-expiratory pressure(PEEP) 4 $cmH_2O$, inspiratory-to-expiratory ratio(I:E ratio) 1:2, fraction of inspired oxygen($F_TO_2$) 1.0. The respiration rate(RR) was adjusted to keep $PaCO_2$ between 35~45 mmHg. The ventilator settings were changed every 30 min in the following sequence : (1) Baseline, as the basal ventilator setting, (2) Inverse ratio, I:E ratio 2:1, (3) high PEEP, adjust PEEP to achieve the same mean inspiratory pressure (MIP) as in the inverse ratio, (4) High $V_T$, $V_T$ 15 mL/kg, (5) high RR, the same minute ventilation (MV) as in the High $V_T$. Subsequently, the same protocol was repeated after instilling 18 mL/kg of perfluorodecalin for PLV. The parameters of gas exchange, lung mechanics, and hemodynamics were examined. Results: (1) The gas ventilation(GV) group showed no significant changes in the $PaO_2$ at all phases. The $PaCO_2$ was lower and the pH was higher at the high $V_T$ and high RR phases(p<0.05). No significant changes in the lung mechanics and hemodynamics parameters were observed. (2) The baseline $PaO_2$ for the PLV was $312{\pm}$ mmHg. This was significantly lower when decreased compared to the baseline $PaO_2$ for GV which was $504{\pm}81$ mmHg(p=0.001). During PLV, the $PaO_2$, was significantly higher at the high PEEP($452{\pm}38$ mmHg) and high $V_T$ ($461{\pm}53$ mmHg) phases compared with the baseline phase. However, it did not change significantly during the inverse I:E ratio or the high RR phases. (3) The $PaCO_2$ was significantly lower at high $V_T$ and RR phases for both the GV and PLV. During the PLV, $PaCO_2$ were significantly higher compared to the GV (p<0.05). (4) There were no important or significant changes in of baseline and high RR phases lung mechanics and hemodynamics parameters during the PLV. Conclusion: During PLV in the normal lung, adequate $V_T$ and PEEP are important for optimal oxygenation.