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Basic Concepts of Acid–Base Physiology
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
It is important to note that pH and hydrogen ion concentration [H+] are inversely related such that an increase in pH describes a decrease in [H+] (Table 47.1). However, the logarithmic scale is nonlinear and, therefore, a change of one pH unit reflects a 10-fold change in [H+] and equal changes in pH are not correlated with equal changes in [H+]. For example, a change of pH from 7.4 to 7.0 (40 nmol/L [H+] to 100 nmol/L [H+]) represents a change of 60 nmol/L [H+], although the same pH change of 0.4, but from 7.4 to 7.8 (40 nmol/L [H+] to 16 nmol/L [H+]), represents a change of only 24 nmol/L [H+].
Resuscitation Physiology
Published in Kenneth D Boffard, Manual of Definitive Surgical Trauma Care: Incorporating Definitive Anaesthetic Trauma Care, 2019
For evaluation of oxygen utilization, however, data are obtainable from arterial blood gases that can indicate what the cells are doing metabolically, which is the most important reflection of the adequacy of their nutrient flow. The pH is the hydrogen ion concentration, which can be determined easily and quickly. Loss of buffering by base excess also mirrors excess acid load. Nevertheless, the pH, BD, and the two carbon fragment metabolites are very important indicators of cellular function in shock.
Acid–Base Balance
Published in Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod, The Primary FRCA Structured Oral Examination Study Guide 1, 2017
Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod
pH: a measure of the acidity of a solution and is calculated as the negative logarithm to the base 10 of the hydrogen ion concentration. Normal serum pH is 7.40 (range 7.36–7.44).
Erosive potential of ice tea beverages and kombuchas
Published in Acta Odontologica Scandinavica, 2023
Elisa Lind, Hilma Mähönen, Rose-Marie Latonen, Lippo Lassila, Marja Pöllänen, Vuokko Loimaranta, Merja Laine
Because dental erosion is caused by many modifying factors, an inference from in vitro to in vivo is only approximate. The main drawback of laboratory-based experiments is that such studies lack critical oral cavity conditions, such as the influence of the salivary flow and especially the acquired salivary pellicle. Furthermore, the 60 min used for the erosive challenge can be considered unreasonably long. Nonetheless, cooled refreshments, such as kombucha and ice tea, are often consumed over a prolonged period of time, and continuous sipping extends the duration of the erosive interlude in the mouth [3]. However, the main aim of the current study was to explore the erosive potential that kombuchas and other widely used tea-based drinks may have. This aim was conducted by evaluating the calcium dissolution from the hydroxyapatite and pH measurements. The techniques such as profilometry and surface microhardness of the bovine tooth samples could further help to quantify the rate of surface erosion. In addition, the pH value only displays the hydrogen ion concentration, therefore it does not indicate the overall acidic content. However, a low pH and an ability to dissolve calcium from hydroxyapatite are qualities known to expose to erosion and fluoride an agent against it [36]. Thus, in spite of its limitations, the present results add to our understanding of the erosive nature of tea beverages and kombuchas.
Management of Citrus sinensis peels for protection and treatment against gastric ulcer induced by ethanol in rats
Published in Biomarkers, 2020
Asmaa Aboul Naser, Eman Younis, Amal El-Feky, Marwa Elbatanony, Manal Hamed
Ethanol is usually used to induce gastric lesions in animal models (Abd-Alla et al. 2016, Fahmi et al.2019a, 2019b). It is characterized by a state of inflammation, oxidative stress, generation of free radicals and apoptosis (Choi et al. 2009, Fahmi et al.2019a, 2019b). The ulcer indices as pH level and lesion counts are used as an indicative factors in stomach ulcer after exposure to toxins (Adhikary et al.2011). The acidity and volume of the gastric secretion are mainly dependent on the pH value, therefore the decrease of hydrogen ion concentration in gastric juice leading to gastric damage (Lullmann et al). These observations were in line with our results through the observed decrease in gastric acidity and increase in gastric volume and lesion counts. The significant decrease in pH and increase in gastric volume in the ulcerated stomach may be attributed to the disequilibrium between free radicals formation and scavenging capacity (Fahmi et al. 2019a, 2019b).
The oceans are changing: impact of ocean warming and acidification on biofouling communities
Published in Biofouling, 2019
Sergey Dobretsov, Ricardo Coutinho, Daniel Rittschof, Maria Salta, Federica Ragazzola, Claire Hellio
An increase in the level of atmospheric CO2 is leading to ocean acidification (Doney et al. 2009). Because the oceanic and atmospheric gas concentrations tend towards equilibrium, ̴ 30% of the added atmospheric CO2 has been taken up by the oceans, decreasing the average pH by ̴ 0.1 pH unit and ultimately changing water chemistry. The observed decrease in pH corresponds to a 26% increase in the hydrogen ion concentration of seawater (Feely et al. 2009). By 2100, the pH is expected to change by -0.13 (421 ppm under RCP2.6), -0.22 (538 ppm under RCP4.5), -0.28 (670 ppm under RCP6.0) and -00.42 pH unit (936 ppm under RCP8.5). Progress has been made in understanding the consequences of changes in pH, carbonate CO32- and the saturation state of CaCO3 for marine organisms and ecosystems (IPCC 2013; Wahl et al. 2015). These chemical and physical changes have direct implications for physiological processes such as photosynthesis, calcification, growth rates and internal pH regulation in a wide range of organisms (McCoy and Ragazzola 2014; Nannini et al. 2015; Evans et al. 2017; Fabricius et al. 2017; Okazaki et al. 2017) which will lead to a disruption of marine ecosystems and a reduction in biodiversity (Hoegh-Guldberg et al. 2007; Milazzo et al. 2014; Beaugrand et al. 2015).