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Thio, Marta, Jennifer A. Dawson, Kelly J. Crossley, Timothy J. Moss, Charles C. Roehr, Graeme R. Polglase, Peter G. Davis, and Stuart B. Hooper. "Delivery of positive end-expiratory pressure to preterm lambs using common resuscitation devices." Archives of Disease in Childhood - Fetal and Neonatal Edition 104, no. 1 (March 2, 2018): F83—F88. http://dx.doi.org/10.1136/archdischild-2017-314064.
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BackgroundIn neonatal resuscitation, a ventilation device providing positive end-expiratory pressure (PEEP) is recommended. There is limited information about PEEP delivery in vivo, using different models of self-inflating bag (SIB) at different inflation rates and PEEP settings.MethodsWe compared PEEP delivery to intubated preterm lambs using four commonly available models of paired SIBs and PEEP valves, with a T-piece, with gas flow of 8 L/min. Peak inspiratory pressure inflations of 30 cmH2O, combined with set PEEP of 5, 7 and 10 cmH2O, were delivered at rates of 20, 40 and 60/min. These combinations were repeated without gas flow. We measured mean PEEP, maximum and minimum PEEP, and its difference (PEEP reduction).ResultsA total of 3288 inflations were analysed. The mean PEEP delivered by all SIBs was lower than set PEEP (P<0.001), although some differences were <0.5 cmH2O. In 55% of combinations, the presence of gas flow resulted in increased PEEP delivery (range difference 0.3–2 cmH2O). The mean PEEP was closer to set PEEP with faster inflation rates and higher set PEEPs. The mean (SD) PEEP reduction was 3.9 (1.6), 8.2 (1.8), 2 (0.6) and 1.1 (0.6) cmH2O with the four SIBs, whereas it was 0.5 (0.2) cmH2O with the T-piece.ConclusionsPEEP delivery with SIBs depends on the set PEEP, inflation rate, device model and gas flow. At recommended inflation rates of 60/min, some devices can deliver PEEP close to the set level, although the reduction in PEEP makes some SIBs potentially less effective for lung recruitment than a T-piece.
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Cramond, T., and J. P. O'Callaghan. "The Combibag: An Evaluation of a New Self-Inflating Resuscitator." Anaesthesia and Intensive Care 14, no. 1 (February 1986): 66–69. http://dx.doi.org/10.1177/0310057x8601400114.
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The Combibag self-inflating resuscitator incorporates an adult and a paediatric segment as well as a two-stage pressure limiting safety valve. The resuscitator is not without problems. A sizeable forward leak of gas can occur beyond the patient valve. The patient valve design is such that a spontaneously breathing patient draws his inspired gas entirely from room air. Problems can also occur with the valve either sticking or being blown forward off its seating, thereby making the resuscitator inoperable and dangerous. The use of a two-stage pressure-limiting safety valve should prevent unnecessary barotrauma but could well lead to unrecognised venting with inadequate ventilation when used by inexperienced personnel.
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Kishimoto, Junichi, Takeo S. Saitoh, and Akira Iwama. "CLEAN LIQUID AND HYBRID GAS GENERATOR SYSTEM FOR INFLATING CAR AIRBAGS." International Journal of Energetic Materials and Chemical Propulsion 4, no. 1-6 (1997): 442–52. http://dx.doi.org/10.1615/intjenergeticmaterialschemprop.v4.i1-6.430.
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Mélega, José M. "Self-inflating system of tissue expansion using gas. Experimental study.(English-Portuguese)." Plastic & Reconstructive Surgery 97, no. 3 (March 1996): 689. http://dx.doi.org/10.1097/00006534-199603000-00064.
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Kimball, W. R., K. B. Kelly, and J. Mead. "Thoracoabdominal blood volume change and its effect on lung and chest wall volumes." Journal of Applied Physiology 61, no. 3 (September 1, 1986): 953–59. http://dx.doi.org/10.1152/jappl.1986.61.3.953.
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The effects of changing blood volume within the thoracoabdominal cavity (Vtab) have been studied in four male subjects trained in respiratory maneuvers. Subjects were studied lying supine in a pressure plethysmograph with inflatable fracture splints placed around both arms and legs. Changes in Vtab were produced by inflating the splints to 30 cmH2O. Thoracic gas volume (Vtg) measured by Boyle's law, and the change in chest wall volume (delta Vw), measured by anteroposterior magnetometers on rib cage and abdomen, were measured almost simultaneously and at two respiratory system volumes. The quantity of blood moved by splint inflation was estimated for each subject at both respiratory system volumes and varied between 215 and 752 ml. The chest wall increased 64 +/- 11.8% (mean +/- SD) of the increase in Vtab. Thus increases in thoracoabdominal blood volume increase Vw about twice the decrease in Vtg.
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Chen, Yizhan, Qingguang Zeng, Lite Zhao, Yuanxing Li, Guangyao Huang, and Bingqian Li. "Optimization of Helium Inflating on Heat Dissipation and Luminescence Properties of the A60 LED Filament Lamps." International Journal of Photoenergy 2019 (April 2, 2019): 1–5. http://dx.doi.org/10.1155/2019/6292036.
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LED filament lamp has the characteristics of nearly 360° lighting angle, high brightness, and low energy consumption, turning it gradually into the best substitute for traditional incandescent lamps. At present, due to the limitations of heat dissipation, the development of high-power LED filament lamp is restricted. Helium is a rare gas with small density and high heat transfer coefficient. It can be used as a cooling and protective gas for LED filament lamp. In this paper, we investigated the effects of helium on the heat dissipation and luminescence performance of the A60 LED filament lamps by detecting the changes of junction temperature, color temperature, and luminous flux of different ratios helium inflating in the different power A60 LED filament lamps. Through the experiment, we found the most cost-effective ratio of helium gas in the A60 LED filament lamps without improving the lamp size and the filament diameter.
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Heller, Hartmut, Gabi Fuchs, and Klaus-Dieter Schuster. "Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits." Journal of Applied Physiology 84, no. 2 (February 1, 1998): 606–11. http://dx.doi.org/10.1152/jappl.1998.84.2.606.
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Heller, Hartmut, Gabi Fuchs, and Klaus-Dieter Schuster. Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits. J. Appl. Physiol. 84(2): 606–611, 1998.—We determined the pulmonary diffusing capacity (Dl) for18O-labeled CO2(C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing 0.9% C18O2or 0.05% NO in nitrogen, with breath-holding periods ranging from 0 to 1 s for C18O2and from 2 to 8 s for NO. The alveolar partial pressures of C18O2and NO were determined by using respiratory mass spectrometry. Dl was calculated from gas exchange during inflation, breath hold, and deflation. We obtained values of 14.0 ± 1.1 and 2.2 ± 0.1 (mean value ± SD) ml ⋅ mmHg−1 ⋅ min−1for[Formula: see text]and Dl NO, respectively. The measured[Formula: see text]/Dl NOratio was one-half that of the theoretically predicted value according to Graham’s law (6.3 ± 0.5 vs. 12, respectively). Analyses of the several mechanisms influencing the determination of[Formula: see text]and Dl NOand their ratio are discussed. An underestimation of the membrane diffusing component for CO2 is considered the likely reason for the low[Formula: see text]/Dl NOratio obtained.
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Gomo, Øystein Herwig, Joar Eilevstjønn, Kari Holte, Anita Yeconia, Hussein Kidanto, and Hege Langli Ersdal. "Delivery of Positive End-Expiratory Pressure Using Self-Inflating Bags during Newborn Resuscitation Is Possible Despite Mask Leak." Neonatology 117, no. 3 (2020): 341–48. http://dx.doi.org/10.1159/000507829.
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<b><i>Background:</i></b> Ventilation is the key intervention to resuscitate non-breathing newborns. Positive end-expiratory pressure (PEEP) may facilitate lung-liquid clearance and help establish functional residual capacity. <b><i>Objectives:</i></b> The aim of this study was to describe how mask leak and ventilation rates affect delivered PEEP and tidal volumes during newborn resuscitations using a self-inflating bag with an integrated PEEP valve. <b><i>Methods:</i></b> This was an observational study including near-term/term newborns who received bag-mask ventilation (BMV) with a new self-inflating bag with a novel 6 mbar PEEP valve, without external gas flow, between October 1, 2016 and June 30, 2018 in rural Tanzania. Helping Babies Breathe-trained midwives performed most of the resuscitations. Pressures and flow were continuously measured and recorded by resuscitation monitors. <b><i>Results:</i></b> In total, 198 newborns with a median gestation of 39 weeks (25th, 75th percentiles 37, 40) and birth weight of 3,100 g (2,580, 3,500) were included. The median delivered PEEP and expired (tidal) volume at different levels of mask leak were 6.0 mbar and 11.3 mL/kg at 0–20% mask leak, 5.5 mbar and 9.3 mL/kg at 20–40%, 5.2 mbar and 7.8 mL/kg at 40–60%, 4.6 mbar and 5.0 mL/kg at 60–80%, and 1.0 mbar and 0.6 mL/kg at 80–100% mask leak. A high ventilation rate (>60/min) nearly halved expired volumes compared to <60/min for 0–60% leak. The BMV rate had a negligible effect on peak inflation pressure (PIP) and PEEP. <b><i>Conclusions:</i></b> Mask leak up to 80% did not impair the provision of recommended PEEP or tidal volumes during BMV with a self-inflating bag. High or low ventilation rates did not significantly affect PIP or PEEP. Expired volumes were reduced at ventilation rates >60/min.
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Zosky, Graeme R., Tibor Z. Janosi, Ágnes Adamicza, Elizabeth M. Bozanich, Vincenzo Cannizzaro, Alexander N. Larcombe, Debra J. Turner, Peter D. Sly, and Zoltán Hantos. "The bimodal quasi-static and dynamic elastance of the murine lung." Journal of Applied Physiology 105, no. 2 (August 2008): 685–92. http://dx.doi.org/10.1152/japplphysiol.90328.2008.
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The double sigmoidal nature of the mouse pressure-volume (PV) curve is well recognized but largely ignored. This study systematically examined the effect of inflating the mouse lung to 40 cm H2O transrespiratory pressure (Prs) in vivo. Adult BALB/c mice were anesthetized, tracheostomized, and mechanically ventilated. Thoracic gas volume was calculated using plethysmography and electrical stimulation of the intercostal muscles. Lung mechanics were tracked during inflation-deflation maneuvers using a modification of the forced oscillation technique. Inflation beyond 20 cm H2O caused a shift in subsequent PV curves with an increase in slope of the inflation limb and an increase in lung volume at 20 cm H2O. There was an overall decrease in tissue elastance and a fundamental change in its volume dependence. This apparent “softening” of the lung could be recovered by partial degassing of the lung or applying a negative transrespiratory pressure such that lung volume decreased below functional residual capacity. Allowing the lung to spontaneously recover revealed that the lung required ∼1 h of mechanical ventilation to return to the original state. We propose a number of possible mechanisms for these observations and suggest that they are most likely explained by the unfolding of alveolar septa and the subsequent redistribution of the fluid lining the alveoli at high transrespiratory pressure.
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Mascaretti, Renata, Luciana Valle, Celso Rebello, and Luciana Haddad. "A Self-Inflating Bag May Cause Hypocapnia in a Rabbit Model of Manual Ventilation Compared to the T-piece Resuscitator." American Journal of Perinatology 34, no. 14 (June 14, 2017): 1405–10. http://dx.doi.org/10.1055/s-0037-1603732.
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Background Manual ventilation is a key aspect that determines the efficiency of neonatal resuscitation and may be performed by specialists using different equipment and professionals. Objective To compare manual ventilation using T-piece resuscitator and self-inflating bag in an experimental model, with regard to gasometric and respiratory mechanical parameters. Methods Adult rabbits were submitted to 10 minutes of ventilation with each device operated by three groups of volunteers: physicians, physiotherapists, and nurses. We measured respiratory mechanics throughout the study as well as blood gas before and after ventilation, and we compared professionals' performance on each device. Results Compared with T-piece, animals ventilated with the self-inflating bag in the nurse group (n = 7) presented a greater minute volume (390 ± 108 vs. 766 ± 410 mL/min, p < 0.05) relative to the physiotherapist group (n = 7, 418 ± 192 vs. 886 ± 787 mL/min), and physician group (n = 7, 438 ± 206 vs. 705 ± 434 mL/min); similar results were found in the nurse, physiotherapist, and physician groups for respiratory alkalosis (7.40 ± 0.11 vs. 7.61 ± 0.02, p < 0.05; 7.37 ± 0.10 vs. 7.52 ± 0.23; and 7.36 ± 0.07 vs. 7.40 ± 0.18 mL/min, respectively), and hypocapnia (32.4 ± 6.9 vs. 23.4 ± 7.5 mm Hg, p < 0.05; 40.4 ± 10.8 vs. 28.0 ± 15.2 mm Hg; and 38.0 ± 13.8 vs. 42.6 ± 18.1 mm Hg, respectively). Conclusion Self-inflating bag resulted in hypocapnia and respiratory alkalosis in the nurse group, and ventilation using a T-piece resulted in a lower tidal and minute volume.
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Escourrou, P., X. Qi, M. Weiss, G. M. Mazmanian, C. Gaultier, and P. Herve. "Influence of pulmonary blood flow on gas exchange in piglets." Journal of Applied Physiology 75, no. 6 (December 1, 1993): 2478–83. http://dx.doi.org/10.1152/jappl.1993.75.6.2478.
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We previously reported that O2 diffusion was limited in piglets. To test the hypothesis of an inadequacy between diffusion and perfusion in piglets (< 4 wk) vs. older pigs (> 8 wk), we compared in these two age groups the effect of an increase (by opening an arteriovenous fistula) or a decrease (by inflating a balloon in the inferior vena cava) in cardiac output (Q) on gas exchange and on the O2 equilibration coefficient D/Q beta [ratio of the diffusion capacity of O2 (D) to the product of Q and the capacitance coefficient of blood (beta)]. In piglets but not in older pigs, a decrease in Q improved the alveolar-arterial Po2 difference (P < 0.05) and D/Q beta (P < 0.05), whereas an increase in Q had the opposite effect. Changes in the alveolar-arterial O2 difference and D/Q beta were linearly correlated with Q (r = 0.75, P < 0.01 and r = 0.88, P < 0.01, respectively). We suggest that the impaired O2 diffusion in piglets was due to inadequate diffusion-perfusion equilibrium of O2.
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Chen, Hai Feng. "Study on the Collaborative Degradation of Acid Red B Dye Wastewater by O3/H2O2." Advanced Materials Research 1010-1012 (August 2014): 872–75. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.872.
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Acid Red B dye wastewater was collaborative degradated by ozone and hydrogen peroxide. Various reaction conditions are studied which affect on decoloration rates of wastewater. The decoloration rate of Wastewater increases with O3 gas flow rate increasing, and also increases with pH value increasing. O3/H2O2 collaborative effects are better than O3 alone, and the decoloration rate is higher with more H2O2 addition. Ozone Oxidation have a good effect to degrade Acid Red B dye wastewater, the decoloration rate can reach 98% with inflating O3 30min. H2O2 synergy can greatly increase the reaction rate, shorten the reaction time, improve the utilization of ozone.
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Chen, Yi-Hao, and Sebastian Heinz. "AGN Jets, Bubbles, and Heat Pumps." Proceedings of the International Astronomical Union 14, S342 (May 2018): 149–53. http://dx.doi.org/10.1017/s1743921318005379.
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AbstractRadio-mode feedback from relativistic jets is one of the prominent heating mechanisms in clusters of galaxies. We present a long-term evolution of high-resolution MHD simulation of jets interacting with an environment modeled to represent the Perseus cluster. We investigate the thermodynamics of the ICM due to the gas motion triggered by the action of the jets and show that low-entropy gas is lifted efficiently in the wake of the inflating radio lobe. We look into the uplift mechanism and estimate the energy budget and the rate of thermal conduction. The redistribution of entropy suggests that heat conduction can play a more significant role in the thermal evolution of the cluster core in the presence of jets, which act effectively as a heat pump, thus heating the ICM more efficiently than jets would by themselves in an isentropic cluster.
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Ranieri, V. Marco, Luciana Mascia, Tommaso Fiore, Francesco Bruno, Antonio Brienza, and Rocco Giuliani. "Cardiorespiratory Effects of Positive End-expiratory Pressure during Progressive Tidal Volume Reduction (Permissive Hypercapnia) in Patients with Acute Respiratory Distress Syndrome." Anesthesiology 83, no. 4 (October 1, 1995): 710–20. http://dx.doi.org/10.1097/00000542-199510000-00010.
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Background In patients with acute respiratory distress syndrome (ARDS), the ventilatory approach is based on tidal volume (VT) of 10-15 ml/kg and positive end-expiratory pressure (PEEP). To avoid further pulmonary injury, decreasing VT and allowing PaCO2 to increase (permissive hypercapnia) has been suggested. Effects of 10 cmH2O of PEEP on respiratory mechanics, hemodynamics, and gas exchange were compared during mechanical ventilation with conventional (10-15 ml/kg) and low (5-8 ml/kg) VT. Methods Nine sedated and paralyzed patients were studied. VT was decreased gradually (50 ml every 20-30 min). Static volume-pressure (V-P) curves, hemodynamics, and gas exchange were measured. Results During mechanical ventilation with conventional VT, V-P curves on PEEP 0 (ZEEP) exhibited an upward convexity in six patients reflecting a progressive reduction in compliance with inflating volume, whereas PEEP resulted in a volume displacement along the flat part of this curve. After VT reduction, V-P curves in the same patients showed an upward concavity, reflecting progressive alveolar recruitment with inflating volume, and application of PEEP resulted in alveolar recruitment. The other three patients showed a V-P curve with an upward concavity; VT reduction increased this concavity, and application of PEEP induced greater alveolar recruitment than during conventional VT. With PEEP, cardiac index decreased by, respectively, 31% during conventional VT and 11% during low VT (P < 0.01); PaO2 increased by 32% and 71% (P < 0.01), respectively, whereas right-to-left venous admixture (Qs/Qt) decreased by 11% and 40%, respectively (P < 0.01). The greatest values of PaO2, static compliance, and oxygen delivery and the lowest values of Qs/Qt (best PEEP) were obtained during application of PEEP with low VT (P < 0.01). Conclusions Although PEEP induced alveolar hyperinflation in most patients during mechanical ventilation with conventional VT, at low VT, there appeared to be a significant alveolar collapse, and PEEP was able to expand these units, improving gas exchange and hemodynamics.
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Leeman, M., V. Z. De Beyl, E. Gilbert, C. Melot, and R. Naeije. "Is nitric oxide released in oleic acid lung injury?" Journal of Applied Physiology 74, no. 2 (February 1, 1993): 650–54. http://dx.doi.org/10.1152/jappl.1993.74.2.650.
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Inhibitors of endothelium-derived nitric oxide synthesis or activity have been reported to enhance hypoxic vasoconstriction in isolated lung preparations. We hypothesized that methylene blue, a guanylate cyclase inhibitor, and N omega-nitro-L-arginine, a nitric oxide synthase inhibitor, would increase pulmonary vascular tone and improve gas exchange in anesthetized and ventilated (inspired O2 fraction 0.4) dogs with oleic acid (OA) lung injury. Mean pulmonary arterial pressure-(Ppa) flow (Q) relationships (generated by a manipulation of venous return, which was increased by opening a femoral arteriovenous bypass or decreased by inflating an inferior vena cava balloon) and gas exchange (evaluated by arterial blood gases and SF6 intrapulmonary shunt determinations) were investigated before and after OA (0.06 ml/kg i.v.) and again after solvent (n = 8), methylene blue (8 mg/kg i.v., n = 10), or N omega-nitro-L-arginine (40 mg/kg i.v., n = 8) in a randomized order. OA administration induced pulmonary hypertension, decreased arterial PO2, and increased intrapulmonary shunt. After OA, solvent had no effect on pulmonary hemodynamics and gas exchange. Both methylene blue and N omega-nitro-L-arginine further increased Ppa at all levels of Q. Only methylene blue, however, improved gas exchange after OA (arterial PO2 from 71 +/- 6 to 89 +/- 12 Torr and intrapulmonary shunt from 44 +/- 6 to 34 +/- 6%, both P < 0.02). These results suggest that nitric oxide is released during OA lung injury and modulates pulmonary hypertension. Whether nitric oxide impairs the regulation of gas exchange in OA lung injury remains uncertain, however.
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Melnick, J., G. Tenorio-Tagle, and E. Telles. "Supersonic turbulence in giant HII regions: clues from 30 Doradus." Astronomy & Astrophysics 649 (May 2021): A175. http://dx.doi.org/10.1051/0004-6361/201937268.
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The tight correlation between turbulence and luminosity in giant HII regions (GHRs) is not well understood. While the luminosity is due to the UV radiation from the massive stars in the ionizing clusters, it is not clear what powers the turbulence. Observations of the two prototypical GHRs in the local Universe, 30 Doradus and NGC 604, show that part of the kinetic energy of the nebular gas comes from the combined stellar winds of the most massive stars, the cluster winds, but not all. We present a study of the kinematics of 30 Doradus based on archival VLT FLAMES/GIRAFFE data and new high-resolution observations with HARPS. We find that the nebular structure and kinematics are shaped by a hot cluster wind and not by the stellar winds of individual stars. The cluster wind powers most of the turbulence of the nebular gas, with a small contribution from the combined gravitational potential of stars and gas. We estimate the total mass of 30 Doradus and we argue that the region does not contain significant amounts of neutral (HI) gas, and that the giant molecular cloud 30 Dor-10, which is close to the center of the nebula in projection, is in fact an inflating cloud tens of parsecs away from R136, the core of the ionizing cluster. We rule out a Kolmogorov-like turbulent kinetic energy cascade as the source of supersonic turbulence in GHRs.
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Heller, Hartmut, and Klaus-Dieter Schuster. "Theta values for C16O18O and C18O2related to respective pulmonary diffusing capacities." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 274, no. 5 (May 1, 1998): R1496—R1499. http://dx.doi.org/10.1152/ajpregu.1998.274.5.r1496.
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The single-breath diffusing capacities for singly and doubly 18O-labeled CO2,[Formula: see text]and[Formula: see text], as well as for NO, were determined in seven anesthetized rabbits to investigate whether the theoretically predicted ratio of specific blood uptake rates of both isotopic CO2species,[Formula: see text]/[Formula: see text]= 2.0, can be derived from the measured values of[Formula: see text]and[Formula: see text]. Data of Dl were obtained by inflating the lungs with gas mixtures containing 0.35% C16O18O or 0.8% C18O2or 0.05% NO in nitrogen, with breath-holding periods of 0.05–0.5 s and 2–12 s for the CO2 and NO tests, respectively.[Formula: see text]/[Formula: see text]was calculated by applying the double-reciprocal Roughton-Forster equation to Dl values obtained in each animal and by assuming that NO diffusing capacity represents the gas conductance of the alveolar-capillary membrane. The measured ratio was[Formula: see text]/[Formula: see text]= 1.9 ± 0.2 (mean ± SD), thus comparing reasonably with the predicted one. Therefore, our findings provide evidence that the greater value of[Formula: see text]is mainly due to the twofold higher probability (or theta value) for C18O2than for C16O18O to disappear within red blood cells via isotopic exchange reactions.
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Scripcaru, Andrei, Anton Knieling, Cristiana Manea, Dragos Valentin Crauciuc, Sofia Mihaela David, Ion Sandu, and Diana Bulgaru Iliescu. "Lethal Helium Intoxication. Determining the Context, Cause and Time of Death." Revista de Chimie 69, no. 10 (November 15, 2018): 2816–18. http://dx.doi.org/10.37358/rc.18.10.6631.
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Helium is the chemical element with atomic number 2, represented by the symbol He. It is an inert, colorless, odorless, insipid monoatomic gas. It has the lowest boiling point and the lowest melting point among the chemical elements and appears only in gaseous state, except for extreme conditions. The use of helium for suicidal purposes is extremely rare. In Romania, suicide has a frequency of 12 per 100,000 inhabitants, which classifies us in the category of countries with low suicide rates. As methods, men use hanging most often while women use more softer methods such as poisoning. Helium is rarely used for suicidal purposes because it is relatively difficult to obtain. Basically, it is not poisoning in the true sense of the word, but rather the substitution of oxygen with helium, which cannot be carried by hemoglobin, and thus transport asphyxia occurs. At the end of the paper we shall exemplify a case of helium poisoning for suicide purposes, purchased from a cylinder for inflating balloons.
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Oliven, A., M. Haxhiu, and S. G. Kelsen. "Expiratory muscle activity during pulmonary edema in the anesthetized dog." Journal of Applied Physiology 73, no. 5 (November 1, 1992): 2062–68. http://dx.doi.org/10.1152/jappl.1992.73.5.2062.
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The present study evaluated the reflex response of the expiratory muscles to pulmonary congestion and edema. The electromyograms of two thoracic and four abdominal expiratory muscles were recorded in 12 anesthetized dogs. Pulmonary edema was induced by rapid saline infusion in six dogs and injection of oleic acid into the pulmonary circulation in the remaining six dogs. Both forms of pulmonary edema reduced pulmonary compliance, interfered with gas exchange, and induced a rapid and shallow breathing pattern. The electrical activity of all abdominal muscles was suppressed during both forms of pulmonary edema. In contrast, the electromyogram activity of the thoracic expiratory muscles was not significantly affected by pulmonary edema. Acute pulmonary arterial hypertension produced in two dogs by inflating a balloon in the left atrium had no effect on ventilation or expiratory muscle electrical activity. In two vagotomized dogs, pulmonary edema did not inhibit the expiratory muscles. We conclude that pulmonary edema suppresses abdominal but not thoracic expiratory muscle activity by vagal reflex pathway(s). Extravasation of fluid into the lung appears to be more important than an increase in pulmonary vascular pressure in eliciting this response.
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Yokoyama, T., S. Tanuma, T. Kudoh, and K. Shibata. "8.6. Magnetic reconnection as the origin of superhot plasmas in the Galactic center." Symposium - International Astronomical Union 184 (1998): 355–56. http://dx.doi.org/10.1017/s0074180900085193.
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Recent X-ray astronomy satellite (e.g., Ginga, ASCA) has revealed that the center of our Galaxy is filled with a large amount of very hot plasmas (a few − 10 keV) on a scale of 100 pc, which are referred to as superhot plasmas. These plasmas are similar to the Galactic Ridge X-ray Emission (GRXE; cf Tanuma et al. 1997), but with larger gas pressure, and their formation mechanism has been a big puzzle. Here we propose a new model, magnetic reconnection model (Fig. 1), to explain the heating as well as the confinement of the Galactic center superhot plasmas, by performing MHD numerical simulations of magnetic reconnection in the situation suitable for the Galactic center. In our model, the magnetic field is amplified by the rotation of the Galactic gas disk (Fig. 2), and inflate from the disk to outside by the Parker instability. The inflating magnetic loop collides with ambient field lines, thus inducing the magnetic reconnection (the same process applied to the solar corona is shown in Yokoyama and Shibata 1995). In this model, energy release per single reconnection event is ΔE ≈ emVrec ≈ 2 × 1051 erg where em = P/β is the energy density of toroidal magnetic field, Vrec = λ2δ is the volume of the event, λ ≈ 60pc is the most unstable wavelength of the Parker instability, and δ ≈ 3pc is the thickness of the Galactic disk. The occurrence rate of this event is f ≈ N/Δτdep ≈ (3 × 104 yr)−1 where N = Vdisk/Vrec is the number of current sheets in the disk, Vdisk is the volume of the disk, and Δτdep is the time scale of energy deposit which is comparable with the time scale of the Galactic rotation. Then, the heating rate is h = fΔE = 2 × 1039 erg s−1 = 100L2–10keV.
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Karasawa, F., M. Tokunaga, Y. Aramaki, M. Shizukuishi, and T. Satoh. "An assessment of a method of inflating cuffs with a nitrous oxide gas mixture to prevent an increase in intracuff pressure in five different tracheal tube designs." Anaesthesia 56, no. 2 (February 2001): 155–59. http://dx.doi.org/10.1046/j.1365-2044.2001.01792.x.
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Walsh, M. C., and W. A. Carlo. "Sustained inflation during HFOV improves pulmonary mechanics and oxygenation." Journal of Applied Physiology 65, no. 1 (July 1, 1988): 368–72. http://dx.doi.org/10.1152/jappl.1988.65.1.368.
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Effective use of high-frequency oscillatory ventilation (HFOV) may require maintenance of adequate lung volume to optimize gas exchange. To determine the impact of inflation during HFOV, sustained inflation was applied at pressures of 5, 10, and 15 cmH2O above mean airway pressure for 3, 10, and 30 s to 15 intubated, paralyzed, anesthetized rabbits after saline lavage to induce surfactant deficiency. Arterial blood gases were recorded in all rabbits while static compliance, resistance, time constant, and changes in functional residual capacity were recorded using the interrupter technique and plethysmograph in seven rabbits. Parameters were recorded before and 2 min after sustained inflation. Arterial PO2, compliance of the respiratory system, and functional residual capacity increased after sustained inflation at pressure levels of at least 10 cmH2O and 10-s duration. As the presence or duration of a sustained inflation was increased, oxygenation improved (P less than or equal to 0.01), but arterial PCO2 increased as longer sustained inflations were used (P less than or equal to 0.005). Sustained inflations of 5 cmH2O above mean airway pressure or of 3-s duration were ineffective. We conclude that either a critical pressure or duration of sustained inflation is needed to improve oxygenation and pulmonary mechanics during HFOV.
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Mutoh, T., W. J. Lamm, L. J. Embree, J. Hildebrandt, and R. K. Albert. "Abdominal distension alters regional pleural pressures and chest wall mechanics in pigs in vivo." Journal of Applied Physiology 70, no. 6 (June 1, 1991): 2611–18. http://dx.doi.org/10.1152/jappl.1991.70.6.2611.
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Abdominal distension (AD) occurs in pregnancy and is also commonly seen in patients with ascites from various causes. Because the abdomen forms part of the "chest wall," the purpose of this study was to clarify the effects of AD on ventilatory mechanics. Airway pressure, four (vertical) regional pleural pressures, and abdominal pressure were measured in five anesthetized, paralyzed, and ventilated upright pigs. The effects of AD on the lung and chest wall were studied by inflating a liquid-filled balloon placed in the abdominal cavity. Respiratory system, chest wall, and lung pressure-volume (PV) relationships were measured on deflation from total lung capacity to residual volume, as well as in the tidal breathing range, before and 15 min after abdominal pressure was raised. Increasing abdominal pressure from 3 to 15 cmH2O decreased total lung capacity and functional residual capacity by approximately 40% and shifted the respiratory system and chest wall PV curves downward and to the right. Much smaller downward shifts in lung deflation curves were seen, with no change in the transdiaphragmatic PV relationship. All regional pleural pressures increased (became less negative) and, in the dependent region, approached 0 cmH2O at functional residual capacity. Tidal compliances of the respiratory system, chest wall, and lung were decreased 43, 42, and 48%, respectively. AD markedly alters respiratory system mechanics primarily by "stiffening" the diaphragm/abdomen part of the chest wall and secondarily by restricting lung expansion, thus shifting the lung PV curve as seen after chest strapping. The less negative pleural pressures in the dependent lung regions suggest that nonuniformities of ventilation could also be accentuated and gas exchange impaired by AD.
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Pilla, Eduardo Sperb, Raôni Bins Pereira, Luiz Alberto Forgiarini Junior, Luiz Felipe Forgiarini, Artur de Oliveira Paludo, Jane Maria Ulbrich Kulczynski, Paulo Francisco Guerreiro Cardoso, and Cristiano Feijó Andrade. "Effects of methylprednisolone on inflammatory activity and oxidative stress in the lungs of brain-dead rats." Jornal Brasileiro de Pneumologia 39, no. 2 (April 2013): 173–80. http://dx.doi.org/10.1590/s1806-37132013000200008.
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OBJECTIVE: To evaluate the effects that early and late systemic administration of methylprednisolone have on lungs in a rat model of brain death. METHODS: Twenty-four male Wistar rats were anesthetized and randomly divided into four groups (n = 6 per group): sham-operated (sham); brain death only (BD); brain death plus methylprednisolone (30 mg/kg i.v.) after 5 min (MP5); and brain death plus methylprednisolone (30 mg/kg i.v.) after 60 min (MP60). In the BD, MP5, and MP60 group rats, we induced brain death by inflating a balloon catheter in the extradural space. All of the animals were observed and ventilated for 120 min. We determined hemodynamic and arterial blood gas variables; wet/dry weight ratio; histological score; levels of thiobarbituric acid reactive substances (TBARS); superoxide dismutase (SOD) activity; and catalase activity. In BAL fluid, we determined differential white cell counts, total protein, and lactate dehydrogenase levels. Myeloperoxidase activity, lipid peroxidation, and TNF-α levels were assessed in lung tissue. RESULTS: No significant differences were found among the groups in terms of hemodynamics, arterial blood gases, wet/dry weight ratio, BAL fluid analysis, or histological score-nor in terms of SOD, myeloperoxidase, and catalase activity. The levels of TBARS were significantly higher in the MP5 and MP60 groups than in the sham and BD groups (p < 0.001). The levels of TNF-α were significantly lower in the MP5 and MP60 groups than in the BD group (p < 0.001). CONCLUSIONS: In this model of brain death, the early and late administration of methylprednisolone had similar effects on inflammatory activity and lipid peroxidation in lung tissue.
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Magnusson, Lennart, Vitas Zemgulis, Arne Tenling, Johan Wernlund, Hans Tyden, Stefan Thelin, and Goran Hedenstierna. "Use of a Vital Capacity Maneuver to Prevent Atelectasis after Cardiopulmonary Bypass." Anesthesiology 88, no. 1 (January 1, 1998): 134–42. http://dx.doi.org/10.1097/00000542-199801000-00021.
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Background Respiratory failure secondary to cardiopulmonary bypass (CPB) remains a major complication after cardiac surgery. The authors previously found that the increase in intrapulmonary shunt was well correlated with the amount of atelectasis. They tested the hypothesis that post-CPB atelectasis can be prevented by a vital capacity maneuver (VCM) performed before termination of the bypass. Methods Eighteen pigs received standard hypothermic CPB (no ventilation during bypass). The VCM was performed in two groups and consisted of inflating the lungs during 15 s to 40 cmH2O at the end of the bypass. In one group, the inspired oxygen fraction (FIO2) was then increased to 1.0. In the second group, the FIO2 was left at 0.4. In the third group, no VCM was performed (control group). Ventilation-perfusion distribution was measured with the inert gas technique and atelectasis by computed tomographic scanning. Results Intrapulmonary shunt increased after bypass in the control group (from 4.9 +/- 4% to 20.8 +/- 11.7%; P < 0.05) and was also increased in the vital capacity group ventilated with 100% oxygen (from 2.2 +/- 1.3% to 6.9 +/- 2.9%; P < 0.01) but was unaffected in the vital capacity group ventilated with 40% oxygen. The control pigs showed extensive atelectasis (21.3 +/- 15.8% of total lung area), which was significantly larger (P < 0.01) than the proportion of atelectasis found in the two vital capacity groups (5.7 +/- 5.7% for the vital capacity group ventilated with 100% oxygen and 2.3 +/- 2.1% for the vital capacity group ventilated with 40% oxygen. Conclusion In this pig model, postcardiopulmonary bypass atelectasis was effectively prevented by a VCM.
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Kim, Jong Won, Sang O. Park, Kyeong Ryong Lee, Dae Young Hong, and Kwang Je Baek. "Efficacy of Amflow®, a Real-Time-Portable Feedback Device for Delivering Appropriate Ventilation in Critically Ill Patients: A Randomised, Controlled, Cross-Over Simulation Study." Emergency Medicine International 2020 (April 24, 2020): 1–7. http://dx.doi.org/10.1155/2020/5296519.
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Objective. The aim of this study was to test whether Amflow® (a newly designed portable ventilation feedback device) can assist rescuers in delivering target tidal volume (VT) and respiration rate (RR) during self-inflating bag (SB) ventilations in various clinical scenarios. Method. This was a simulation study with a prospective cross-over design. A total of 40 trained participants who underwent training for SB ventilation were recruited. Using a SB with or without Amflow® alternately, participants delivered ventilations to test lungs connected to a gas flow analyser in each of three different scenarios: acute respiratory distress syndrome (ARDS; 315–385 ml ranges for 350 ml target VT, with 20 breaths/min); cardiopulmonary resuscitation (CPR; 450–550 ml ranges for 500 ml target VT with 10 breaths/min); and adult head trauma (630–770 ml ranges for 700 ml target VT with 15 breaths/min). Results. The feedback group (SB with Amflow®) demonstrated a significantly higher percentage of delivering the appropriate VT ranges than the no-feedback group for both ARDS (58.6% versus 23.5%, respectively) and CPR (85.4% versus 41.0%, respectively) (all p<0.05). However, there was no significant difference between the two groups in the percentage of delivering the appropriate VT ranges in head trauma patients (65.9% versus 68.3%, respectively; p=0.092). In all three scenarios, a higher percentage of target RR delivered was achieved in the feedback group (88.3%, 99.2%, and 96.3%, respectively) compared with the no-feedback group (5.8%, 12.5%, and 10.0%, respectively) (all p<0.05). Conclusion. The Amflow® device could be useful for rescuers in delivering SB ventilation with appropriate VT and RR simultaneously in various critical situations, except for clinical cases that demand greater delivered VT.
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La Rocca, J., and J. J. Perez Fontan. "Effect of liquid inflation on the viscoelastic behavior of the lungs in developing piglets." Journal of Applied Physiology 77, no. 4 (October 1, 1994): 1653–58. http://dx.doi.org/10.1152/jappl.1994.77.4.1653.
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Viscoelastic dissipation through stress relaxation decreases during the first weeks after birth in the piglet's lungs (J. Appl. Physiol. 73: 1297–1309, 1992). To characterize the mechanism of this decrease, we compared the stress relaxation undergone by the lungs of six newborn and six 9-wk-old piglets when the airway opening was occluded in the course of air and saline inflations. The amplitude of stress relaxation, determined from the mono-exponential decay ultimately adopted by the transpulmonary pressure during the occlusions, related linearly to the increases in lung elastic recoil preceding the occlusions. The slope of this relationship was greater in the newborn than in the 9-wk-old piglets during air inflations and similar at the two ages during saline inflations. Both the ratio of stress relaxation to elastic recoil and the time constant of the relaxations were similar during air and saline inflations and were independent of inflation rate and lung volume at the start of the inflations. These findings indicate that the postnatal decrease in stress relaxation is caused primarily by developmental changes in the geometry of the gas-liquid interface. They are also consistent with the notion that the viscoelastic stresses generated by the gas liquid interface and lung tissue are well matched for a given elastic recoil.
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Parry, Matthew F., and Daniele A. Steer. "Brane Gas Inflation." Journal of High Energy Physics 2002, no. 02 (February 22, 2002): 032. http://dx.doi.org/10.1088/1126-6708/2002/02/032.
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Tingay, David G., Graeme R. Polglase, Risha Bhatia, Clare A. Berry, Robert J. Kopotic, Clinton P. Kopotic, Yong Song, Edgardo Szyld, Alan H. Jobe, and J. Jane Pillow. "Pressure-limited sustained inflation vs. gradual tidal inflations for resuscitation in preterm lambs." Journal of Applied Physiology 118, no. 7 (April 1, 2015): 890–97. http://dx.doi.org/10.1152/japplphysiol.00985.2014.
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Support of the mechanically complex preterm lung needs to facilitate aeration while avoiding ventilation heterogeneities: whether to achieve this gradually or quickly remains unclear. We compared the effect of gradual vs. constant tidal inflations and a pressure-limited sustained inflation (SI) at birth on gas exchange, lung mechanics, gravity-dependent lung volume distribution, and lung injury in 131-day gestation preterm lambs. Lambs were resuscitated with either 1) a 20-s, 40-cmH2O pressure-limited SI (PressSI), 2) a gradual increase in tidal volume (Vt) over 5-min from 3 ml/kg to 7 ml/kg (IncrVt), or 3) 7 ml/kg Vt from birth. All lambs were subsequently ventilated for 15 min with 7 ml/kg Vt with the same end-expiratory pressure. Lung mechanics, gas exchange and spatial distribution of end-expiratory volume (EEV), and tidal ventilation (electrical impedance tomography) were recorded regularly. At 15 min, early mRNA tissue markers of lung injury were assessed. The IncrVt group resulted in greater tissue hysteresivity at 5 min ( P = 0.017; two-way ANOVA), higher alveolar-arterial oxygen difference from 10 min ( P < 0.01), and least uniform gravity-dependent distribution of EEV. There were no other differences in lung mechanics between groups, and the PressSI and 7 ml/kg Vt groups behaved similarly throughout. EEV was more uniformly distributed, but Vt least so, in the PressSI group. There were no differences in mRNA markers of lung injury. A gradual increase in Vt from birth resulted in less recruitment of the gravity-dependent lung with worse oxygenation. There was no benefit of a SI at birth over mechanical ventilation with 7 ml/kg Vt.
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Perez Fontan, J. J., and A. O. Ray. "Pressure-flow behavior of a bronchopleural fistula during mechanical ventilation with positive pressure." Journal of Applied Physiology 66, no. 4 (April 1, 1989): 1789–99. http://dx.doi.org/10.1152/jappl.1989.66.4.1789.
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We examined the mechanical behavior of a bronchopleural fistula created by sectioning a small subpleural bronchus in seven anesthetized lambs. The pressure across the fistula was measured as the difference between the pressure recorded by a retrograde bronchial catheter inserted in the vicinity of the fistula and the outflow pressure at the fistula exit. The effective resistance of the fistula (Rf) was computed by dividing this pressure difference by the gas flow through the fistula measured at the outlet of an intrapleural tube adjacent to the fistula. Rf increased by 114 +/- 25% (SE) when we inflated the lungs in a stepwise manner from a tracheal pressure of 2–20 cmH2O. Rf also increased when inflation pressure varied continuously; this increase, however, was less evident when we decreased the inflation time from 1.0 to 0.2 s. The relationship between Rf and lung volume was similar during the stepwise inflations and deflations but showed marked hysteresis during the continuous inflation-deflation maneuvers, when Rf was greater during deflation than inflation. Our results suggest that the fistula behaves as a compliant pathway whose relevant transmural pressure is the transmural pressure at or near the fistula's exit. We attribute the increase in Rf during inflation to decreases in transmural pressure caused by convective and dissipative losses inside the fistula and by the stress applied by the chest wall on the outer surface of the fistula.
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Daws, John. "Nitrogen Inflation for Passenger Car and Light Truck Tires." Tire Science and Technology 39, no. 2 (June 1, 2011): 125–60. http://dx.doi.org/10.2346/1.3593787.
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Abstract Nitrogen as an inflation gas for passenger car and light truck tires use is widely available commercially. Consumers are confronted with a bewildering selection of offerings, and suppliers tout the purity of their nitrogen generation systems and effectiveness of using the gas in place of air. This paper develops models for the initial tire nitrogen purity, the inflation pressure loss rate, and the evolution of the nitrogen gas purity in the tire as a function of the gas used to top off the tire over its life. A series of simulations using the basic model is developed for air and various purities of nitrogen initial inflation with monthly top-off using air or various purities of nitrogen. The initial inflation pressure loss rate is shown as a function of the tire’s initial nitrogen purity. This paper proposes the use of the total oxygen passing through the tire over its lifetime as a metric for evaluation of various inflation schemes. This metric is developed for several of the popular available nitrogen inflation purities using both air and nitrogen as a top-off gas.
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Barosi, Luciano, Francisco A. Brito, and Amilcar R. Queiroz. "Noncommutative field gas driven inflation." Journal of Cosmology and Astroparticle Physics 2008, no. 04 (April 3, 2008): 005. http://dx.doi.org/10.1088/1475-7516/2008/04/005.
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Pack, A. I., R. J. Galante, and A. P. Fishman. "Control of interbreath interval in the African lungfish." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 259, no. 1 (July 1, 1990): R139—R146. http://dx.doi.org/10.1152/ajpregu.1990.259.1.r139.
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We have performed studies to examine the effect of variations in intrapulmonary pressure on the interval between lung breaths in the African lungfish. Studies were performed in two different preparations. In the first we produced changes in lung pressure using a controlled-infusion pump. Increases in intrapulmonary pressure prolonged the interval between lung breaths. At a pressure of 2.5 cmH2O the average interval was 2.6 +/- 1.8 min (mean +/- SD); at 5.0 cmH2O, 8.1 +/- 3.5 min; and at 7.5 cmH2O, 16.2 +/- 3.8 min. Inflations of the lung early in the interbreath interval had less of an effect on its duration than inflations later in the interval. In the second preparation we used a system in which gas flowed continuously through both lungs. Intrapulmonary pressure was varied by changing outlet pressure and O2 concentration by changing the composition of the gas mixture. This allowed separate control of both O2 concentration and intrapulmonary pressure. At a fixed O2 concentration intrapulmonary pressure increased the duration of the interval between lung breaths. At a fixed pressure, reductions in O2 concentration shortened the interval. There was no significant interactive effect of O2 and pressure. Lung inflation did not alter the frequency of gill ventilation. These results imply that a reflex highly similar to the Hering-Breuer expiratory-promoting reflex was already present in the African lungfish.
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Wei, Jian Zheng, Rui Qiang Ma, Hui Feng Tan, and Xing Wen Du. "Simulation for Gas-Membrane Interaction of Folded Membrane Tubes during Inflation." Advanced Materials Research 594-597 (November 2012): 2627–31. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2627.
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It is very important for gas-membrane interaction between compressible ideal gas and elastic membrane structure of space folded tubes during inflation deployment. This paper analyses gas flow field of the folded tube by the finite volume method, and simulates inflation process of the membrane tube with different height of the baffle. A finite volume model of gas flow field is established in the folded membrane tube, and variations of the pressure inside the membrane tube are obtained with height of the baffle and inlet flow rate. And then, the gas-membrane interaction is calculated by couple the CFD and CSD solver. The results show that the pressure on the membrane wall increases with the inflation velocity, and inlet velocity of inflation gives rise to the vibration of the membrane.
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Musch, Guido, R. Scott Harris, Marcos F. Vidal Melo, Kevin R. O’Neill, J. Dominick H. Layfield, Tilo Winkler, and Jose G. Venegas. "Mechanism by Which a Sustained Inflation Can Worsen Oxygenation in Acute Lung Injury." Anesthesiology 100, no. 2 (February 1, 2004): 323–30. http://dx.doi.org/10.1097/00000542-200402000-00022.
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Background Sustained lung inflations (recruitment maneuvers [RMs]) are occasionally used during mechanical ventilation of patients with acute lung injury to restore aeration to atelectatic alveoli. However, RMs do not improve, and may even worsen, gas exchange in a fraction of these patients. In this study, the authors sought to determine the mechanism by which an RM can impair gas exchange in acute lung injury. Methods The authors selected a model of acute lung injury that was unlikely to exhibit sustained recruitment in response to a lung inflation. In five sheep, lung injury was induced by lavage with 0.2% polysorbate 80 in saline. Positron emission tomography and [13N]nitrogen were used to assess regional lung function in dependent, middle, and nondependent lung regions. Physiologic data and positron emission scans were collected before and 5 min after a sustained inflation (continuous positive airway pressure of 50 cm H2O for 30 s). Results All animals showed greater loss of aeration and higher perfusion and shunting blood flow in the dependent region. After the RM, Pao2 decreased in all animals by 35 +/- 22 mmHg (P < 0.05). This decrease in Pao2 was associated with redistribution of pulmonary blood flow from the middle, more aerated region to the dependent, less aerated region (P < 0.05) and with an increase in the fraction of pulmonary blood flow that was shunted in the dependent region (P < 0.05). Neither respiratory compliance nor aeration of the dependent region improved after the RM. Conclusions When a sustained inflation does not restore aeration to atelectatic regions, it can worsen oxygenation by increasing the fraction of pulmonary blood flow that is shunted in nonaerated regions.
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Waddell, Walter H., R. Christopher Napier, and Donald S. Tracey. "Nitrogen Inflation of Tires." Rubber Chemistry and Technology 82, no. 2 (May 1, 2009): 229–43. http://dx.doi.org/10.5254/1.3548247.
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Abstract Inflation pressure retention (IPR as a loss rate) is a key predictive parameter to improving tire durability. Improved Tire IPR, manifested as reduced percent pressure loss per month values, has statistically been shown to be a direct result of innerliner compounds made with increasing amounts of halobutyl rubber when used as a direct replacement for natural rubber if other variables are constant. Roadwheel performance of tires is highest when using 100-phr of halobutyl rubber in the innerliner compound. This affords a tire with desirably low IPR loss rate values, desirably low tire intracarcass pressure (ICP) values, and increased tire durability as measured in hours until failure on laboratory roadwheels. The use of nitrogen gas in tires in severe service conditions is known, and a variety of benefits have been claimed for use in passenger car tires. In order to test specific claims, tires with innerliners having a 100-phr bromobutyl rubber, and 80/20 and 60/40 bromobutyl/natural rubber blends were studied using three filling gases: dry, pure nitrogen (99.4%), dry air and a 50/50 mixture of dry nitrogen/oxygen (49.8%). Performance was measured for new and oven-aged tires. It is shown that the direct benefits of using nitrogen are in reducing the Tire IPR loss rate values, and in reducing aging since oxygen gas has been initially excluded. Other claimed benefits are found to be a secondary result of the lower Tire IPR loss rate values. Use of nitrogen as the inflation gas does not benefit the measured cavity gas temperature or tire rolling resistance, both of which are shown to be tire pressure dependent, but not dependent upon the filling gas when measured at equal tire inflation pressures.
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George, Amy E., Tatiana Garcia, Benjamin H. Stahlschmidt, and Duane C. Chapman. "Ontogenetic changes in swimming speed of silver carp, bighead carp, and grass carp larvae: implications for larval dispersal." PeerJ 6 (November 2, 2018): e5869. http://dx.doi.org/10.7717/peerj.5869.
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Bighead, silver, and grass carps are invasive in the waterways of central North America, and grass carp reproduction in tributaries of the Great Lakes has now been documented. Questions about recruitment potential motivate a need for accurate models of egg and larval dispersal. Quantitative data on swimming behaviors and capabilities during early ontogeny are needed to improve these dispersal models. We measured ontogenetic changes in routine and maximum swimming speeds of bighead, grass, and silver carp larvae. Daily measurements of routine swimming speed were taken for two weeks post-hatch using a still camera and the LARVEL program, a custom image-analysis software. Larval swimming speed was calculated using larval locations in subsequent image frames and time between images. Using an endurance chamber, we determined the maximum swimming speed of larvae (post-gas bladder inflation) for four to eight weeks post-hatch. For all species, larval swimming speeds showed similar trends with respect to ontogeny: increases in maximum speed, and decreases in routine speed. Maximum speeds of bighead and grass carp larvae were similar and generally faster than silver carp larvae. Routine swimming speeds of all larvae were highest before gas bladder inflation, most likely because gas bladder inflation allowed the fish to maintain position without swimming. Downward vertical velocities of pre-gas bladder inflation fish were faster than upward velocities. Among the three species, grass carp larvae had the highest swimming speeds in the pre-gas bladder inflation period, and the lowest speeds in the post-gas bladder inflation period. Knowledge of swimming capability of these species, along with hydraulic characteristics of a river, enables further refinement of models of embryonic and larval drift.
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Hinder, Murray Kenneth, Thomas Drevhammar, Snorri Donaldsson, Matthew Boustred, Matthew Crott, and Mark Brian Tracy. "T-piece resuscitators: can they provide safe ventilation in a low compliant newborn lung?" Archives of Disease in Childhood - Fetal and Neonatal Edition 106, no. 1 (June 16, 2020): 25–30. http://dx.doi.org/10.1136/archdischild-2019-318673.
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BackgroundT-piece resuscitators (TPRs) are used for primary newborn resuscitation in birthing and emergency rooms worldwide. A recent study has shown spikes in peak inflation pressure (PIP) over set values with two brands of TPRs inbuilt into infant warmer/resuscitation platforms. We aimed to compare delivered ventilation between two TPR drivers with inflation pressure spikes to a standard handheld TPR in a low test lung compliance (Crs), leak-free bench test model.MethodsA single operator provided positive pressure ventilation to a low compliance test lung model (Crs 0.2–1 mL/cmH2O) at set PIP of 15, 25, 35 and 40 cmH2O. Two TPR devices with known spikes (Draeger Resuscitaire, GE Panda) were compared with handheld Neopuff (NP). Recommended settings for positive end-expiratory pressure (5 cmH2O), inflation rate of 60/min and gas flow rate 10 L/min were used.Results2293 inflations were analysed. Draeger and GE TPR drivers delivered higher mean PIP (Panda 18.9–49.5 cmH2O; Draeger 21.2–49.2 cmH2O and NP 14.8–39.9 cmH2O) compared with set PIP and tidal volumes (TVs) compared with the NP (Panda 2.9–7.8 mL; Draeger 3.8–8.1 mL; compared with NP 2.2–6.0 mL), outside the prespecified acceptable range (±10% of set PIP and ±10% TV compared with NP).ConclusionThe observed spike in PIP over set values with Draeger and GE Panda systems resulted in significantly higher delivered volumes compared with the NP with identical settings. Manufacturers need to address these differences. The effect on patient outcomes is unknown.
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VITALIS, TIMOTHY ZOLTAN, and GRAHAM SHELTON. "Breathing in Rana Pipiens: the Mechanism of Ventilation." Journal of Experimental Biology 154, no. 1 (November 1, 1990): 537–56. http://dx.doi.org/10.1242/jeb.154.1.537.
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The mechanism and pattern of ventilation in unrestrained Rana pipiens were investigated by simultaneous measurements of pulmonary pressure, buccal pressure and air flow at the nostrils. The buccal cavity was ventilated continuously at a rate of 90±3.2oscillations min−1 by low-amplitude pressure swings above and below atmospheric. The lungs were ventilated intermittently by the buccal pump at a rate of 6.3±0.8breathsmin−1. Expiration of gas from the nostrils occurred on two occasions during a lung ventilation. Ventilation of the lungs was achieved by precise timing of two valves, the nostrils and glottis. The timing of the valves determined the volume of expiratory flow on these two occasions and its relationship to inspiratory flow. Thus, the breathing movements could cause inflation, deflation, or no change in the lung volume. Periodically the lung was inflated by a sequence of successive breaths. During inflations the nostrils closed simultaneously with glottal opening and almost no gas was expired during the first expiratory phase. This caused a complete mixing of buccal contents and pulmonary gas and this mixture was pumped back into the lung. Deflations were characterized by a delay in nostril closing that resulted in a large outflow of gas from the lung and buccal cavity during the first phase of expiration. More gas left the system than was pumped into the lungs. The results suggest that coherent air flow from glottis to nostrils, as required by the ‘jet stream’ hypothesis of Gans et al. (1969), is not likely to occur.
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BRANDENBERGER, ROBERT H. "STRING GAS COSMOLOGY AND STRUCTURE FORMATION." Modern Physics Letters A 22, no. 25n28 (September 14, 2007): 1875–85. http://dx.doi.org/10.1142/s0217732307025091.
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For suitable cosmological backgrounds, thermal fluctuations of a gas of strings can generate a scale-invariant spectrum of cosmological fluctuations without requiring a phase of inflationary expansion. We highlight the key points of this mechanism, and discuss cosmological backgrounds in which this scenario can be realized. The spectrum of cosmo-logical perturbations has a small red tilt (like in scalar field-driven inflation) but (unlike in inflation) there is a small blue tilt of the spectrum of gravitational waves.
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Septina, Fanny. "Determinan Ekspor Di Indonesia." Jurnal Ecodemica: Jurnal Ekonomi, Manajemen, dan Bisnis 4, no. 2 (September 1, 2020): 307–17. http://dx.doi.org/10.31294/jeco.v4i2.8275.
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ABSTRACTThis study aims to explore macroeconomic factors that affect non-oil and gas exports in Indonesia. The research data are non-oil and gas export data, Gross Domestic Product, inflation, US dollar exchange rate, foreign direct investment in the 2010-2019 period published by Bank Indonesia statistics. The research method uses the Vector Error Correction Model (VECM) analysis with the Augmented Dickey Fuller (ADF) stationary test, Johansen's cointegration test, Granger causality test, Error Correction Model. The results showed there was a cointegration relationship between all dependent and independent variables, a direct relationship with the US dollar exchange rate and inflation on Gross Domestic Product, Gross Domestic Product on exports. In the short term Gross Domestic Product, inflation, exchange rates, and foreign direct investment have no significant effect on non-oil and gas exports. In the long run, Gross Domestic Product has a significant effect on non-oil and gas exports.Keywords: non-oil export, macroeconomy, cointegration, causality, error correction model
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Shinkawa, Hideichi, Jiro Hozawa, and Tomonori Takasaka. "Middle Ear Inflation with a Gas Mixture." ORL 54, no. 3 (1992): 144–47. http://dx.doi.org/10.1159/000276284.
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Modell, H. I., P. Beeman, and J. Mendenhall. "Influence of G-suit abdominal bladder inflation on gas exchange during +GZ stress." Journal of Applied Physiology 58, no. 2 (February 1, 1985): 506–13. http://dx.doi.org/10.1152/jappl.1985.58.2.506.
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Available data relating duration of +GZ stress to blood gas exchange status is limited. Furthermore, studies focusing on pulmonary gas exchange during +GZ stress when abdominal restriction is imposed have yielded conflicting results. To examine the time course of blood gas changes occurring during exposure to +GZ stress in dogs and the influence of G-suit abdominal bladder inflation on this time course, seven spontaneously breathing pentobarbital-anesthetized adult mongrel dogs were exposed to 60 s of up to +5 GZ stress with and without G-suit abdominal bladder inflation. Arterial and mixed venous blood were sampled for blood gas analysis during the first and last 20 s of the exposure and at 3 min postexposure. Little change in blood gas status was seen at +3 GZ regardless of G-suit status. However, with G-suit inflation, arterial PO2 fell by a mean of 14.7 Torr during the first 20 s at +4 Gz (P less than 0.01, t test) and 20.6 Torr at +5 GZ (P less than 0.01). It continued to fall an additional 10 Torr during the next 40 s at both +4 and +5 GZ. Arterial PO2 was still 5–10 Torr below control values (P less than 0.05) 3 min postexposure. A second series of experiments paralleling the first focused on blood gas status during repeated exposure to acceleration. Blood gas status was assessed in five dogs during the late 20 s of two 60-s exposures separated by 3 min at 0 GZ. No significant differences between the initial and repeated exposures were detected. The data indicate that G-suit abdominal bladder inflation promotes increased venous admixture.
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DIKSA, I. GUSTI BAGUS NGURAH. "ANALISIS KETERKAITAN ANTAR KELOMPOK PENGELUARAN INFLASI MENGGUNAKAN VECTOR AUTOREGRESSIVE MODEL." Jambura Journal of Probability and Statistics 2, no. 1 (April 4, 2021): 14–27. http://dx.doi.org/10.34312/jjps.v2i1.7763.
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In this study, testing steps were carried out, namely the stationarity test, determining the optimum lag, hypothesis testing and the formation of the VAR model, the Granger causality test and classical assumptions. The data used are month to month inflation data for each inflation expenditure group in Indonesia for the period January 2013 to December 2019. The inflation expenditure group is foodstuffs; processed food, beverages, cigarettes and tobacco; housing, water, electricity, gas and fuel; clothing; health; education, recreation and sports; and transportation, communication, and financial services. However, in this study only five inflation expenditure groups were used, namely foodstuffs; processed food, beverages, cigarettes and tobacco; housing, water, electricity, gas and fuel; clothing; as well as transportation, communication and financial services. The purpose of this study is to analyze the relationship between inflation expenditure groups and to find a forecasting model for inflation expenditure groups in Indonesia. After the Granger causality test was carried out, all probability values between endogenous variables, namely the five groups of inflation expenditures were less than 0,05 or rejected H0. Therefore, it can be concluded that there is a causal relationship between endogenous variables.
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Erchiqui, Fouad, Mhamed Souli, Toufik Kanit, Abdellatif Imad, Boudlal Aziz, and Ahmed El Moumen. "Characterization of Polymeric Membranes Under Large Deformations Using Fluid-Structure Coupling." International Journal of Applied Mechanics 07, no. 05 (October 2015): 1550068. http://dx.doi.org/10.1142/s1758825115500684.
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The mechanical properties of Ogden material under biaxial deformation are obtained by using the bubble inflation technique. First, pressure inside the bubble and height at the hemispheric pole are recorded during bubble inflation experiment. Thereafter, Ogden's theory of hyperelasticity is employed to define the constitutive model of flat circular thermoplastic membranes (CTPMs) and nonlinear equilibrium equations of the inflation process are solved using finite difference method with deferred corrections. As a last step, a neuronal algorithm artificial neural network (ANN) model is employed to minimize the difference between calculated and measured parameters to determine material constants for Ogden model. This technique was successfully implemented for acrylonitrile-butadiene-styrene (ABS), at typical thermoforming temperatures, 145°C. When solving for the bubble inflation, the recorded pressure is applied uniformly on the structure. During the process inflation, the pressure is not uniform inside the bubble, thus full gas dynamic equations need to be solved to get the appropriate nonuniform pressure to be applied on the structure. In order to simulate the inflation process accurately, computational fluid dynamics in a moving fluid domain as well as fluid structure interaction (FSI) algorithms need to be performed for accurate pressure prediction and fluid structure interface coupling. Fluid structure interaction solver is then required to couple the dynamic of the inflated gas to structure motion. Recent development has been performed for the simulation of gas dynamic in a moving domain using arbitrary Lagrangian Eulerian (ALE) techniques.
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Safsafi, A., I. Khay, F. Salamate, H. Chakir, and M. Bennai. "On Chaplygin Gas Braneworld Inflation with Monomial Potential." Advances in High Energy Physics 2018 (June 25, 2018): 1–9. http://dx.doi.org/10.1155/2018/2958605.
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We study the Chaplygin gas model as a candidate for inflation in the framework of the Randall-Sundrum type II braneworld model. We consider the original and generalized Chaplygin gas model in the presence of monomial potential. The inflationary spectrum perturbation parameters are reformulated and evaluated in the high-energy limit and we found that they depend on several parameters. We also showed that these perturbation parameters are widely compatible with the recent Planck data for a particular choice of the parameters space of the model. A suitable observational central value of ns≃0.965 is also obtained in the case of original and generalized Chaplygin gas.
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Yu, Hong, Maoyong Cao, Tanbo Zhu, and Fanming Liu. "Study of Heating Device for Sulfur Hexafluoride Gasification." Sensor Letters 18, no. 2 (February 1, 2020): 157–63. http://dx.doi.org/10.1166/sl.2020.4201.
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Sulfur hexafluoride (SF6) gas has been used to gas-insulated switchgear (GIS) because of its insulation properties and extinguishing characteristics. The processing of liquid sulfur hexafluoride from cylinders into GIS is endothermic. The processing gas inflation always leads to decrease SF6 gas inflation speed due to the lack of heat supplement and the infiltrated moisture will stick on the GIS equipment, especially at the valve outlet. In the paper, a heater detection device for sulfur hexafluoride (SF6) steel cylinder is developed. The new heater device will monitor and display the specific temperature and humidity of the valve outlet instantaneously and then heat and dry the sulfur hexafluoride (SF6) steel cylinder with automatic and stability. Then it helps to speed up the sulfur hexafluoride gasification. Meanwhile, the whole device is portable in safety.
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Kahya, E. O., and B. Pourhassan. "Observational constraints on the extended Chaplygin gas inflation." Astrophysics and Space Science 353, no. 2 (October 2014): 677–82. http://dx.doi.org/10.1007/s10509-014-2069-6.
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Campo, Sergio del. "Single-field inflation à la generalized Chaplygin gas." Journal of Cosmology and Astroparticle Physics 2013, no. 11 (November 5, 2013): 004. http://dx.doi.org/10.1088/1475-7516/2013/11/004.
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Rieger, P. W., and R. C. Summerfelt. "Microvideography of gas bladder inflation in larval walleye." Journal of Fish Biology 53, no. 1 (July 1998): 93–99. http://dx.doi.org/10.1111/j.1095-8649.1998.tb00112.x.
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