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The History of Bioelectromagnetism
Published in Shoogo Ueno, Tsukasa Shigemitsu, Bioelectromagnetism, 2022
Tsukasa Shigemitsu, Shoogo Ueno, Masamichi Kato
In 1935, Karl Matthes (1905–1962), a German physician, made a device which measured continuously the oxyhemoglobin saturation of human blood, the in vivo transillumination of the ear (Severinghaus, 1986). In 1939, using two different wave lengths of light (red and infrared) he developed the first red and infrared ear oxygen saturation meter. Infrared wavelength is absorbed more by oxygenated hemoglobin and red wavelength is absorbed more by deoxygenated hemoglobin. Glenn Allan Millikan (1906–1947), an American physiologist, inventor, University of Pennsylvania, Philadelphia, was the son of Robert Andrews Millikan (1868–1953), an American experimental physicist. Father Millikan won the Nobel Prize in Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric effect. Glenn Millikan made an ear oximeter (Millikan and Taylor, 1942). Although the ear oximeter performed very poorly due to the fact that light absorption of ear is affected very little by arterial blood, he coined term oximeter. The pulse-oximeter would consist of a probe attached to the patient’s ear lobe or finger and a display unit. Using NIR in the range of 0.6–1 μm, the pulse-oximeter was used as a non-invasive method for monitoring a person’s oxygenation of the blood. The oxygenation of the blood was measured as a function of time by determining the absorption at two different wavelengths. In 1947, Glenn Millikan was killed by a falling rock during mountain climbing.
Light, Life, and Measurement
Published in Thomas M. Nordlund, Peter M. Hoffmann, Quantitative Understanding of Biosystems, 2019
Thomas M. Nordlund, Peter M. Hoffmann
The short introduction above introduces energies, wavelengths and spectra associated with biological life illuminated by light. These quantities should convince even the casual reader that measurement of light and the properties of light sources and light absorbers will be critical to our understanding of the roles of light in enabling life on earth. The importance of light measurement in biophysics has two aspects. First, light directly affects or enables most biological life. We must understand the physical and biological mechanisms of this interaction. Second, since the beginning of the twentieth century, light has been the premier tool for probing the structures and states of organisms and biological molecules. Such experimental methods can often be noninvasive, allowing measurement of an organism’s or biomolecule’s properties without damage or perturbation. Any routine trip to a medical clinic illustrates the ubiquity of light as a biomedical tool. Following measurement of a patient’s weight and height, a small sleeve is clamped over the end of a patient’s finger. This sleeve, a pulse oximeter, employs light to measure the oxygenation level of the patient’s blood. Light can also be used to purposely cause a change. (See end-of-chapter problems.) To understand such changes and their photophysical or photochemical mechanisms, a clear understanding of the nature and measurement of photons is needed.
Analysing IoT Data for Anxiety and Stress Monitoring: A Systematic Mapping Study and Taxonomy
Published in International Journal of Human–Computer Interaction, 2022
Leonardo dos Santos Paula, Lucas Pfeiffer Salomão Dias, Rosemary Francisco, Jorge Luis Victória Barbosa
Blood Oxygenation measures the amount of oxygen in the blood (Silva, 2021). In contrast, Blood Pressure measures the pressure exerted by the blood against the artery walls (MedlinePlus, 2021), and the Blood Pulse Wave is the shape and rhythm of the blood wave generated from the heart’s contraction (Biofourmis, 2021).