China
Africa
Explore chapters and articles related to this topic
Chemical Factors
Published in Michael J. Kennish, Ecology of Estuaries Physical and Chemical Aspects, 2019
where K is a constant for the given gas, B is the Bunsen coefficient, and T is the absolute temperature. At a particular temperature, an atmospheric gas obeys Henry’s law — the solubility of the gas is directly proportional to the partial pressure it exerts.
Pressure change
Published in Nicholas Green, Steven Gaydos, Hutchison Ewan, Edward Nicol, Handbook of Aviation and Space Medicine, 2019
Nicholas Green, Steven Gaydos, Hutchison Ewan, Edward Nicol
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.
Ear Trauma
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, 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.
Antioxidative protection of haemoglobin microparticles (HbMPs) by PolyDopamine
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Olga Baidukova, Quan Wang, Saranya Chaiwaree, Dorette Freyer, Ausanai Prapan, Radostina Georgieva, Lian Zhao, Hans Bäumler
The amount of oxygenated Hb (OxyHb) in HbMPs was calculated via the determination of the oxygen pressure (pO2) in the solutions adding 50 μL 10% K3[Fe(CN)6, which reacts with OxyHb to release the Hb-bound oxygen. The partial pressure of 600 µl of HbMPs or PD-HBMPS suspensions was recorded with an optical needle type oxygen sensor NTH-PSt7 (PreSens, Germany) which was connected to a portable oxygen meter Microx 4 (PreSens, Germany). Then 50 µl of 10% aqueous K3[Fe(CN)6 solution was added to the samples and the change in pO2 was measured. When a stable value was reached, the measurement was stopped. The change in pO2 before and after the incubation of K3[Fe(CN)6 was converted into the concentration of released oxygen cO2 with the following formula known as Henry’s Law:
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.