The Development of the Radiotracer Concept
Garimella V. S. Rayudu, Lelio G. Colombetti in Radiotracers for Medical Applications, 2019
Hevesy first heard about a possible heavy hydrogen in 1913, but it didn’t pan out. By 1931 Aston had demonstrated stable isotopes all through the periodic tables — but not in hydrogen. Harold Urey at Columbia had mild but valid theoretical reasons for thinking there must be an H-2. He agreed with Hevesy on the lack of heavy element diffusion differences, but hydrogen isotopes had a 100% difference in mass. If Aston couldn’t find the H, H-2 separation with his technique, he might be able to with a diffusion technique.23 He evaporated 4 ℓ of liquid hydrogen down to 1 mℓ. An optical spectrum of this residual showed a distinct line precisely where H-2 should be. Urey felt that if a large volume of water was electrolyzed the H-l should bubble off faster than H-2. There was an industrial production of hydrogen and oxygen that did just that electrolysis on a large scale. Urey obtained samples from the electrolysis cells and measured their density change. A large volume of electrolyzed water gained from 8.3 lb/gal to over 9 lb/gal. You could measure the difference on a bathroom scale.
Methods of Protein Iodination
Erwin Regoeczi in Iodine-Labeled Plasma Proteins, 2019
Electrolysis is a phenomenon that accompanies the conduction of current in liquids. Whenever a mass of matter is enriched in free electrons relative to another mass of matter, such as M1 relative to M2 in Figure 30, the potential difference will equalize by the discharge of electrons from M1 to M2. For the discharge to take place, M1 and M2 have to be connected by a conductor that can be a solid, a liquid, or a gas. In each of these media, the mechanism of the conduction of electricity is markedly different from one another.
Principles of Radioiodination and Iodine-Labeled Tracers in Biomedical Investigation †
Garimella V. S. Rayudu, Lelio G. Colombetti in Radiotracers for Medical Applications, 2019
Instead of using chemical oxidants, Pennisi and Rosa82 performed electrolysis at a constant current level to convert iodide to iodine for the radioiodination of insulin and other proteins. The procedure is mild and a labeling efficiency of between 30 and 80% has been reported. The electrolytic cell (Figure 12) has a 10-mℓ platinum crucible as the anode, and the platinum cathode (diameter 0.8 to 1.0 mm) is surrounded by a dialyzing cellophane membrane. The crucible contains the solution of the protein to be radioiodinated, along with the radioiodide in isotonic saline solution. A slow and controlled rate of electrolysis results in a steady liberation of radioiodine and thus intrinsically leads to an even distribution of radioiodine among the protein molecules. In the chemical oxidation method, a reactive species of radioiodine is formed instantaneously. In a typical electrolytic radioiodination, 10 to 50 mg of a protein in isotonic saline are mixed with 1 to 5 mCi of radioiodide and are electrolyzed for between 30 and 60 min in a platinum crucible as the anode and a platinum cathode in a small dialysis chamber with a constant current of 6 to 12 μA. The original method83 was modified to perform iodination at a microlevel (1 to 5 μg of protein). The free radioiodide is separated by conventional procedure. The labeled material retains high levels of immunologic and biological activity. The inherent advantages of the technique are that no chemical oxidant or reductant is used and that the substitution level can be controlled by the amount of current or carrier iodide. The disadvantages are the lower specific activity, prolonged exposure of protein to radioiodide, and protein denaturing from dilution and temperature of the electrolysis.
Non-thermal techniques: a new approach to removing pesticide residues from fresh products and water
Published in Toxin Reviews, 2021
Reza Abedi-Firoozjah, Zahra Ghasempour, Sirous Khorram, Arezou Khezerlou, Ali Ehsani
Due to the fact that the CP simultaneously contains three factors that reduce toxins, which include energy charged particles such as electrons and ions, UV light and free radicals, and is more effective on the surface of food than other methods such as EB and Gamma, it is preferred. In most of the mentioned cases, the percentage of reduction of all kinds of toxins is higher than 70% and it has the ability to be used industrially in the place. On the other hand, there is no secondary environmental pollution. The high energy of gamma rays and EB and the high dose used can penetrate food and alter the chemical composition of food, such as toxins. Also, in addition to being expensive, the equipment of such systems is scarce in most countries, making it impossible to use. The salt electrolysis system is for the production of chlorine compounds, and the possibility of chlorine penetration into agricultural products is high, and few studies have been conducted in this regard (Lieberman and Lichtenberg 2005, Bermúdez-Aguirre 2019).
Antimicrobial effects of a pulsed electromagnetic field: an in vitro polymicrobial periodontal subgingival biofilm model
Published in Biofouling, 2020
Marcelo Faveri, Danilo Eduardo Calgaro Miquelleto, Bruno Bueno-Silva, João Marcos Spessoto Pingueiro, Luciene Cristina Figueiredo, Oleg Dolkart, Elad Yakobson, Shlomo Barak, Magda Feres, Jamil Awad Shibli
PEMF effects were unique; the growth rates of seven of the 31 species (E. nodatum, F. nucleatum ssp. nucleatum, S. intermedius, S. anginosus, S. mutans, F. nucleatum ssp. vicentii and C. ochracea) were significantly reduced, while four species (A. israelli, C. gingivalis, C. showae, and A. odontolyticus) showed increased rates although not statiscally significant. Taken together, it could be suggested that there was an important difference between these species, which contributed to their specific responses to the PEMF. Indeed, E. nodatum, S. intermedius, S. anginosus, S. mutans, A. israelli and A. odontolyticus are Gram-positive species, whereas both F. nucleatum, C. ochracea, C. gingivalis, C. showae are Gram-negative. In addition, C. ochracea and C. gingivalis, C. showae also reacted differently to the PEMF, suggesting that membrane morphology and composition could not be the only factor. It is far more likely that these fields interact with the dental biofilm on multiple levels simultaneously changing the climax community of this specific environment. However, it must be pointed out that the present study evaluated the impact of PEMF relative to a single parameter. Different electromagnetic fields could increase not only the number and duration of the pulse but also the frequency. These factors could induce irreversible electroporation mechanisms of microorganism inactivation, such as electrolysis and release of several free radicals, which could result in killing bacteria, alone or associated with electric fields (Rubin et al. 2019).
Phase I and phase II metabolism simulation of antitumor-active 2-hydroxyacridinone with electrochemistry coupled on-line with mass spectrometry
Published in Xenobiotica, 2019
Agnieszka Potęga, Dorota Garwolińska, Anna M. Nowicka, Michał Fau, Agata Kot-Wasik, Zofia Mazerska
Assuming that during oxidation process of 2-OH-AC two electrons are exchanged, the total electrolysis of 0.5 mM compound should be achieved at the time of obtaining the charge of 200 mC. Unfortunately, despite long electrolysis (over 1 day), the maximum charge achieved was only 29 mC. A possible explanation of this situation is that the oxidation products of 2-OH-AC strongly adsorbed on the electrode surface and effectively blocked it. With electrolysis progress the intensity of the current signals drastically decreased (Figure 2(a)). In addition, a new oxidation signal at circa 0.06 V (a2) was also well visible. It was related to the third cathodic peak (c1). The introduction of GSH to the solution of 2-OH-AC significantly minimized the effects of the electrolysis process. This observation may point out the presence of interactions between oxidation products of 2-OH-AC and GSH. The CPE of a mixture of 2-OH-AC and GSH (Figure 2(b)) revealed the anodic signal at circa 0.42 V (a1) with increasing intensity. Also, a new signal emerged at circa 0.31 V (a2) and its height increased with time of electrolysis. This product peak was due to the reduction of the transformed 2-OH-AC molecule.
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