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Our Radiation Environment
Published in T. D. Luckey, Radiation Hormesis, 2020
The most common chemical reaction following the absorption of ionizing radiation by water is the formation of a cascade of free radicals which avidly seek any possible means to form stable complexes with neighboring molecules. The most reactive species in this drama are the hydroxyl ion and the hydrated electron. Many strange and unusual molecules are formed when these two come to rest. A concise explanation of different types of radiations, their energy transfer processes, and the formation of free radicals was summarized in BEIR V.58 An electron is stripped from the water molecule to produce a positively charged water molecule, H2O+, plus an electron which immediately attaches to another water molecule to form a “hydrated electron”. This free electron reacts with nearby molecules to produce strange and sometimes biologically important compounds. The ionized water and normal water react to produce the hydronium ion and the hydroxyl radical:
Site-Specific Chemical Modification of Proteins
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
Before going further it might be useful to define some terms that we will be using. When most of us think of acids we tend to think of substances such as hydrochloric acid, sulfuric acid, and acetic acid, substances which can donate protons in aqueous solution to form hydronium ions (H3O+). Likewise a base is most usually considered to be a substance (e.g., hydroxide ion — OH−) which can accept protons. In other words, by this definition a base possesses an unshared electron pair with which it can attract and hold a proton. This is the classical Bronsted definition of acids and bases. Organic chemists find it more useful to use the Lewis definition of acids and bases. Using this definition, an acid is a substance that can form a covalent bond by accepting an electron pair and a base has an unshared electron pair. Taking this a step further then, Lewis acids are electrophilic while Lewis bases are nucleophilic.
Alternate Methods for Visualizing and Constructing
Published in Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk, Survival Guide to General Chemistry, 2019
Patrick E. McMahon, Rosemary F. McMahon, Bohdan B. Khomtchouk
Example: Show the formation of a coordinate covalent bond between H+ and a water molecule to for the hydronium ion (H3O+).
The Warburg hypothesis and weak ELF biointeractions
Published in Electromagnetic Biology and Medicine, 2020
Among the more recent ELF experimental studies are those initiated by Grimaldi (D’Emilia et al. 2015) involving water structure. Exposing water to ICR field combinations tuned to the hydronium ion (H3O+) results in a sharply reduced pH, or equivalently, in an increase in uncoupled protons. Additionally, a series of experiments in Novikov’s laboratory (Novikov and Fesenko 2001) have probed the use of ICR signals in teasing apart various metabolic reactions. Especially interesting is that this laboratory has found it particularly useful to simultaneously apply different ICR frequencies corresponding to more than one cation by simply applying the electronic sum of the various signals. Presumably the system to which this summed signal is being applied is “smart enough” to respond to each of the ICR conditions that comprise the electronic sum. In so doing it is hoped that the system under study will correspond more faithfully to real-world biochemical changes, which occur either simultaneously or in rapid succession. In a loose comparison, the Novikov application of several ICR frequencies at once might be considered equivalent to taking a diverse group of pharmaceutically prescribed pills together.
ION cyclotron resonance: Geomagnetic strategy for living systems?
Published in Electromagnetic Biology and Medicine, 2019
The details of the hypothetical connection between ICR-related biological effects and proton hopping rest on the associated structural changes in vicinal water structures adjacent to the stimulated cation. Hydronium ions in this nearby water are affected by the associated magnetostatic field, following a helical path conforming to the rotating electric dipole established by hydronium and the hydroxyl ion (Liboff et al., 2017). The net effect is the associated transport of protons usually described as proton-hopping, but with a path slightly different from how this effect is usually described, helical instead of simply directional.
Boron phenyl alanine targeted ionic liquid decorated chitosan nanoparticles for mitoxantrone delivery to glioma cell line
Published in Pharmaceutical Development and Technology, 2021
Fatemeh Dousti, Monireh Soleimanbeigi, Mina Mirian, Jaleh Varshosaz, Farshid Hassanzadeh, Yaser Kasesaz, Mahboubeh Rostami
the profile and the rate of drug release from NPs depend on several environmental and structural features, including pH, temperature, drug solubility, the ability of diffusion, the erosion, and swelling profile of the nanoparticle matrix (Son et al. 2017). Two different methods were used to study the swelling behavior of NPs in an aqueous solution with different pHs (7.4 and 5.5). First, the amount of weight gained after soaking in water for 48 h; and second, by following the hydrodynamic size in colloidal dispersion after a while. The results were provided in Table 3; since the chitosan NPs contain pH-modulating groups (UA and Im moieties), a slight change in the environmental pH disturbs the electrical balance and causes water-absorbing and swelling. Therefore, any weight gain can mean swelling of the system, and the more this weight gain, the higher the percentage of swelling. The weight gaining for different NPs at two pH (7.4 and 5.5) is almost promising results for formulated NPs; among two types of NPs, it seems that BPA-CSUAIm NPs at the same time have a better swelling index. As the pH decreases, the protonation of the UA and remaining amine groups of CS leads to an increase in electrostatic repulsions between CS chains, the penetration of water molecules increases, and so induces swelling in NPs (Kumar et al. 2014; Son et al. 2017). In CSUAIm NPs, within 2 h in pH of 5.5, a moderate increase in hydrodynamic size occurs; at the same time, this increment is more evident in CSUA NPs. It seems that in the initial hours, the cationic pendant groups prevent the entry of hydronium cations into the nanoparticle network. UA groups, on the other hand, facilitate the entry of hydronium ions. So in the initial hours, the CSUAIm NPs experience a minor change in their hydrodynamic sizes than CSUA NPs. These results are very satisfying for drug release from a pH-responsive system.