The phenomenon of Manning-Oosawa counterion condensation is given an explicit statistical mechanical and qualitative basis via a dressed polyelectrolyte formalism in connection with the topology of the electrostatic free-energy surface and is derived explicitly in terms of the adsorption excess of ions about the polyion via the nonlinear Poisson-Boltzmann equation. The approach is closely analogous to the theory of ion binding in micelles. Our results not only elucidate a Poisson-Boltzmann analysis, which shows that a fraction of the counterions lie within a finite volume around the polyion even if the volume of the system tends towards infinity, but also provide a direct link between Manning's theta-the number of condensed counterions for each polyion site-and a statistical thermodynamic quantity, namely, the adsorption excess per monomer.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC39538 | PMC |
http://dx.doi.org/10.1073/pnas.93.9.4342 | DOI Listing |
Anal Chim Acta
March 2025
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China. Electronic address:
Background: Based on the low volatility and refractory nature of Tetracycline (TC), excessive use leads to its continuous accumulation in water environments, posing serious risks to the ecological environment and human health. Although a very limited number of nanomaterials capable of simultaneously detecting and removing TC have been fabricated, they generally exist issues associated with a single detection signal ("on" or "off") or low adsorption rates with low adsorption capacities. As a result, it is crucial to develop a reliable technique to achieve ratiometric detection as well as rapid and efficient removal of TC.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
January 2025
University of Belgrade-Institute of Chemistry, Technology and Metallurgy, Department of Chemistry, Njegoševa 12, 11000 Belgrade, Republic of Serbia. Electronic address:
The lipophilicity of thirteen tacrine/piperidine-4-carboxamide derivatives was assessed using reversed-phase thin-layer chromatography (RP-TLC) with MeOH and acetonitrile (ACN) as organic modifiers. Among the parameters evaluated, the R and C values obtained using MeOH were identified as the most reliable for characterizing the lipophilicity of the investigated compounds. The observed differences in lipophilicity among the derivatives resulted from a delicate interplay of substituent effects (hydrophobicity, polarity, steric hindrance, and electronic effects), positional influence, and characteristics of the organic modifier.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
Microplastics (MPs) and perfluorobutanoic acid (PFBA), emerging contaminants, are ubiquitous in the environment and toxic to organisms. The interaction of MPs with other contaminants can affect their toxicity. However, the impact of MPs on PFBA toxicity remains unknown.
View Article and Find Full Text PDFAnal Chem
January 2025
Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Meilong Road, Shanghai 200237, P. R. China.
Protein methylation has attracted increasing attention due to its significant regulatory roles in various biological processes. However, the diversity of methylation forms, subtle differences between methylated and nonmodified sites, and their ultralow abundances pose substantial challenges for capturing and isolating methylated peptides from biological samples. Herein, we develop a chromatographic method that utilizes 4-sulfonylcalix[4]arene (SC4A) as a mobile phase additive and Click-Maltose as the stationary phase to separate methylated/nonmethylated peptides through the adsorption of the SC4A-(Me3) complex.
View Article and Find Full Text PDFInorg Chem
January 2025
Jiangxi Province Key Laboratory of Nuclear Physics and Technology, East China University of Technology, Nanchang 330013, China.
Recycling waste salt in the dry reprocessing of nuclear fuel and reducing electric energy consumption in the electrorefining process are crucial steps toward addressing significant challenges in this field. The present study proposes a novel approach to purify waste salt by selectively adsorbing excessive fission products using 5A molecular sieves (5A), based on the principles of electrorefining, with the ultimate aim of achieving sustainable development in nuclear fuel. First, Lutetium (Lu)-Bi alloy was synthesized through constant potential electrolysis in the LiCl-KCl-LuCl melt, resulting in a 90.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!