Extracting Information from the Ionic Strength Dependence of Electrophoretic Mobility by Use of the Slope Plot

The effective mobility (μ_ep) is the main parameter characterizing the electrophoretic behavior of a given solute. It is well-known that μ_ep is a decreasing function of the ionic strength for all solutes. Nevertheless, the decrease depends strongly on the nature of the solute (small ions, polyelectrolyte, nanoparticles). Different electrophoretic models from the literature can describe this ionic strength dependence. However, the complexity of the ionic strength dependence with the solute characteristics and the variety of analytical expressions of the different existing models make the phenomenological ionic strength dependence difficult to comprehend. In this work, the ionic strength dependence of the effective mobility was systematically investigated on a set of different solutes [small mono- and multicharged ions, polyelectrolytes, and organic/inorganic (nano)­particles]. The phenomenological decrease of electrophoretic mobility with ionic strength was experimentally described by calculating the relative electrophoretic mobility decrease per ionic strength decade (<i>S</i>) in the range of 0.005–0.1 M ionic strength. Interestingly, the “slope plot” displaying <i>S</i> as a function of the solute electrophoretic mobility at 5 mM ionic strength allows for defining different zones that are characteristic of the solute nature. This new representative approach should greatly help experimentalists to better understand the ionic strength dependence of analyte and may contribute to the characterization of unknown analytes via their ionic strength dependence of electrophoretic mobility

Genetic polymorphisms associated with obesity in the Arab world: a systematic review

Background Obesity, one of the most common chronic health conditions worldwide, is a multifactorial disease caused by complex genetic and environmental interactions. Several association studies have revealed a considerable number of candidate loci for obesity; however, the genotype–phenotype correlations remain unclear. To date, no comprehensive systematic review has been conducted to investigate the genetic risk factors for obesity among Arabs. Objectives This study aimed to systematically review the genetic polymorphisms that are significantly associated with obesity in Arabs. Methods We searched four literature databases (PubMed, Science Direct, Scopus, and Google Scholar) from inception until May 2020 to obtain all reported genetic data related to obesity in Arab populations. Quality assessment and data extraction were performed individually by three investigators. Results In total, 59 studies comprising a total of 15,488 cases and 9,760 controls were included in the systematic review. A total of 76 variants located within or near 49 genes were reported to be significantly associated with obesity. Among the 76 variants, two were described as unique to Arabs, as they have not been previously reported in other populations, and 19 were reported to be distinctively associated with obesity in Arabs but not in non-Arab populations. Conclusions There appears to be a unique genetic and clinical susceptibility profile of obesity in Arab patients.Other Information Published in: International Journal of Obesity License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1038/s41366-021-00867-6</p

Effective Charge Determination of Dendrigraft Poly‑l‑lysine by Capillary Isotachophoresis

In this work, capillary isotachophoresis (ITP) was used to determine the effective charge of the first five generations of dendrigraft poly-l-lysines. This approach, which is based on the linear dependence of ITP zone length of the solute on its concentration and effective charge, offers a simple and straightforward method for effective charge determination. The cationic ITP system employed in this work yields good linearity, repeatability and sharp zones. The value of effective charge number per one lysine residue obtained for long linear poly-l-lysine is in a good agreement with the Manning theoretical value (0.5). Results obtained for dendrigraft poly-l-lysines show a dramatic decrease in the effective charge number per lysine residue with increasing generation number, from 0.84 for short oligolysines (generation 1) down to 0.08 for the fifth generation. This decrease in effective charge is due to the proximity of charged groups in the dendrigraft structure of higher generation number