Ear Trauma
John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed in Paediatrics, The Ear, Skull Base, 2018
Henry’s law states that the amount of gas dissolved in a tissue is proportional to the pressure on that tissue. During descent (compression), the increased ambient pressure results in a greater amount of nitrogen dissolved in both the arterial and venous blood. During ascent (decompression), as the ambient pressure falls, a gas phase will form within the tissue unless the gas is metabolized or removed at a sufficiently fast rate. Nitrogen and other inert gases, which cannot be metabolized, are only transferred via a concentration gradient from the tissues back into the blood stream. Nitrogen has a low partition coefficient (water/oil, 0.19) as it is more soluble in lipids than in water. Consequently, its transfer from the tissues to the vasculature is slow. Once in the blood it is transported to the lungs where the gas tensions in the pulmonary capillaries are equilibrated with the partial pressures of gases in the alveoli before exhalation. If subsequent decompression is too rapid, nitrogen bubbles will form.
Paper 5 Answers
James Day, Amy Thomson, Tamsin McAllister, Nawal Bahal in Get Through, 2014
Henry’s law: at a constant temperature, the amount of gas dissolved in a liquid is proportional to the partial pressure of the gas (above the solvent) in equilibrium with the liquid where pgas = partial pressure of gas above liquid (atm)kH = Henry’s constantc = solubility of gas
Pressure change
Nicholas Green, Steven Gaydos, Hutchison Ewan, Edward Nicol in Handbook of Aviation and Space Medicine, 2019
Henry’s Law states that the mass of gas dissolved in a liquid is proportional to the partial pressure in the gas above the liquid: Rapid reduction of environmental pressure causes bubbles of nitrogen to form in the blood and tissues.
Respirable aerosol exposures of nicotine dry powder formulations to in vitro, ex vivo, and in vivo pre-clinical models demonstrate consistency of pharmacokinetic profiles
Published in Inhalation Toxicology, 2019
Davide Sciuscio, Julia Hoeng, Manuel C. Peitsch, Patrick Vanscheeuwijck
Nicotine is an alkaloid with numerous biological effects (Benowitz 2009). Apart from its known effects as a neurological stimulant, nicotine offers potential therapeutic avenues (Caldwell et al. 2012; Fagerström 2014). The main route of exposure in humans is via inhalation in tobacco smoke or electronic nicotine delivery systems, although skin patches, chewing gums and other oral delivery products such as lozenges and mints containing nicotine have been developed over the past decades. Because of its physicochemical properties, nicotine has complex pharmacokinetics (PK) in the lungs. Nicotine is a semi-volatile substance with a vapor pressure of 0.038 mm Hg at 25 °C (Boublik et al. 1984). Water solubility is very high, yielding a low Henry’s law constant of 3.0 × 10−9 atm-m3/mole (US National Library of Medicine 2018) (Medicine). This means that when nicotine is in the vapor phase, its deposition upon inhalation is very rapid and occurs primarily in the buccal mucosa and larger airways, compared to a more peripheral lung deposition when administered via tobacco smoke or tobacco-derived aerosol (Lunell et al. 1996). In addition, nicotine partitions nearly equally into membrane lipids and tissue water, with a LogP of 1.17 according to the U.S. National Library of Medicine (2018). Nicotine is therefore likely to have high mobility in well-perfused tissues, such as the lung (Gerde and Scott 2001), despite participating in an acid-base equilibrium at physiological pH (Benowitz 2009). Nicotine formulations from respirable-sized powders without a vapor component would likely be suitable for controlling therapeutic administration via inhalation (Caldwell et al. 2012).
Evaluating the efficiency of enzyme accelerated CO2 capture: chemical kinetics modelling for interpreting measurement results
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2021
Lorenzo Parri, Ada Fort, Anna Lo Grasso, Marco Mugnaini, Valerio Vignoli, Clemente Capasso, Sonia Del Prete, Maria Novella Romanelli, Claudiu T. Supuran
In all these equations, [X] is the concentration of the species X. 2 dissolving in water from the gaseous phase, and [CO2]* is the saturation value of the overall concentration of aqueous CO2 concentration, due to Henry’s law. [CO2]* depends on temperature, pressure and on the concentration of gaseous CO2. In (2) and (3) a first order kinetics was assumed on the basis of the experimental observations, which are supported by the satisfactory behaviour of the developed model.
QSAR study of antituberculosis activity of oxadiazole derivatives using DFT calculations
Published in Journal of Receptors and Signal Transduction, 2022
Sharieh Hosseini, Sepideh Ketabi, Golnar Hasheminasab
In order to determine which of the descriptors in the equation has the greatest effect on anti-Tb activity, the pattern is drawn on the effect of the descriptor (Figure 2). In this diagram, the descriptors above the graph have a positive effect and the ones below the diagram have a negative effect on the activity. According to the diagram, the most effect is related to the Henry’s law constant, and the least is related to the C–N bond.
Related Knowledge Centers
- Physical Chemistry
- Partial Pressure
- Decompression Sickness
- Carbonation
- Carbon Dioxide
- Hypoxia
- Environmental Chemistry
- Van 'T Hoff Equation
- Formaldehyde
- Ph