Nutrition for health and sports performance
Nick Draper, Helen Marshall in Exercise Physiology, 2014
An ionic bond is formed between two atoms when one of the atoms donates an electron to another, thus completing the outer shell of electrons for each and creating a stable chemical product. An example of this can be found in Figure 2.3 where chlorine (Cl) accepts one electron from sodium (Na). By doing this Cl becomes a negatively charged chloride ion (Cl−) as it has more electrons than protons and Na becomes a positively charged sodium ion (Na+) because it has one electron fewer. Atoms that lose electrons and become positively charged are called cations (to remember this think of the t as + and positive) and those that accept electrons and become negatively charged ions are called anions (think of the n as n egative). The resultant compound for this example is sodium chloride (NaCl) or table salt. It is this compound in our sweat that gives sweat a salty taste.
Useful Principles for the Crystallization of Proteins
Hartmut Michel in Crystallization of Membrane Proteins, 1991
Aside from its general applicability and utility in obtaining crystals for diffraction analysis,59 it also has the advantage that it is most effective at minimal ionic strength and it provides a low electron density medium. The first feature is important because it provides for higher ligand binding affinities than does a high ionic strength medium such as concentrated salt. As a consequence there is greater ease in obtaining isomorphous heavy-atom derivatives and in forming protein-ligand complexes for study by difference Fourier techniques. The second characteristic, a low electron-dense medium, implies a generally lower background or noise level for protein structures derived by X-ray diffraction and presumably, therefore, a more ready interpretation.
The Noncollagenous Proteins of the Intervertebral Disc *
Peter Ghosh in The Biology of the Intervertebral Disc, 2019
Ultracentrifugation in density gradients of cesium chloride, cesium sulfate, or cesium bromide allows molecules to be separated on the basis of differences in their buoyant densities. The strong salt solutions used may also prevent ionic interactions during these separations. In addition, the inclusion of protein dénaturants such as GuHCl can effect separation of high buoyant density PG from other disc proteins of lower buoyant densities.34
Genotoxicity of selected pharmaceuticals, their binary mixtures, and varying environmental conditions – study with human adenocarcinoma cancer HT29 cell line
Published in Drug and Chemical Toxicology, 2021
Monika Wieczerzak, Jacek Namieśnik, Błażej Kudłak
Model substances selected for the study: diclofenac sodium salt (diclofenac s.) (CAS no. 153907–79-6), chloramphenicol (CAS no. 56–75-7), oxytetracycline hydrochloride (oxytetracycline h.) (CAS no. 2058–46-0), fluoxetine hydrochloride (fluoxetine h.) (CAS no. 56296–78-7), estrone (CAS no. 53–16-7), ketoprofen (CAS no. 22071–15-4), progesterone (CAS no. 57–83-0), gemfibrozil (CAS no. 25812–30-0), and androstenedione (CAS no. 63–05-8) were purchased from Sigma Aldrich (Germany) and were of analytical purity grade (>99%). Diazepam (CAS no. 439–14-5, purity grade >99%) was purchased from LGC Standards (UK). Inorganic ions in the salt form (KCl (CAS no. 7447–40-7), NH4Cl (CAS no. 12125–02-9), NaF (CAS no. 7681–49-4), NaBr (CAS no. 7647–15-6)) were purchased from Avantor Performance Materials S.A. (Poland) while NaCl (CAS no. 7647–14-5) from Sigma Aldrich (Germany). pH values were adjusted with concentrated solutions of NaOH (CAS no. 1310–73-2) or HCl (CAS no. 7647–01-0) purchased from Avantor Performance Materials S.A. (Poland). All purchased ions were analytical purity grade >99%.
Spatial distribution of total and bioavailable heavy metal contents in soil from agricultural, residential, and industrial areas in Sudan
Published in Toxin Reviews, 2019
Mohammed A. Ashaiekh, Mohamed A. H. Eltayeb, Ali H. Ali, Ammar M. Ebrahim, Isam Salih, Abubakr M. Idris
Recent geochemical studies on soil have addressed serious effects of urbanization and industrialization on the relevant environments (Ordonez et al.2015, Boudreault et al.2016, Hu et al.2016, Yang et al.2016). Among many environmental pollutants, heavy metals have been considered by the United States Environmental Protection Agency (USEPA) as priority control pollutants because of their high toxicity and bioaccumulation, besides their abundance and multi-purpose usage (Chen et al.2015). Both essential and non-essential heavy metals cause threat to the health of human beings and animals when they are transformed from salt to ionic or organometallic moieties forms (Chen et al.2015). While controlled levels of essential heavy metals play vital roles in biological systems, high doses are poisonous and cause hazardous effects on organisms. Non-essential heavy metals are harmful even at low doses. For instance, Pb causes harms in the hematological and neurological systems (USEPA 2004, Jooste et al.2015). Pb can also affect the cardiovascular system and kidneys (ATSDR 2007, Jooste et al.2015). Cd causes lung cancer, kidney dysfunction, pulmonary adenocarcinomas, hypertension, bone fractures, and prostatic proliferative lesions (Zukowska and Biziuk 2008). In general, the International Agency for Research on Cancer (IARC) classified Cr, Cd, As, Ni, and Co as having potential carcinogen effect (Bian et al.2015).
Stability screening of pharmaceutical cocrystals
Published in Pharmaceutical Development and Technology, 2021
Kenneth C. Waterman, Alisa K. Waterman, Teslin M. Botoy, Jane Li, Fenghe Qiu, Michael Hawley
Pharmaceutical cocrystals consist of complexes of active pharmaceutical ingredients (APIs) with other inert molecules. The association between the two molecules usually results from specific hydrogen bonding or π-stacking (Steed 2013). There have also been several ionic cocrystals reported (where a drug is complexed with a salt) (Braga et al. 2011). Cocrystals can significantly increase the aqueous solubility of an API compared to its un-complexed form (Good & Rodríguez-Hornedo 2009; Thakuria et al. 2013). As such, they have become an increasingly valuable adjunct to other methods of improving the in vivo performance of APIs (such as using salts and making amorphous dispersions). As with other high-energy API forms, cocrystals can potentially dissolve quickly and give a relatively high solubility in an environment that is less favorable for the two-molecule interactions (such as in the gastrointestinal tract).