Toxic effects due to high aluminum body loads were observed in a number of conditions following ingestion of Al-containing antacids. Bio-availability of aluminum depends not only on the solubility of the ingested salt but also on the physico-chemical properties of the soluble Al complexes formed in body fluids. Amino acids may, upon interaction with Al-salts, form absorbable Al-complexes. Hence, complex formation equilibria between Al(3+) and either, L- histidine or L-tyrosine were studied by glass electrode potentiometric (0.1 mol/L LiCl ionic medium, 298 K), proton NMR and uv spectrophotometric measurements. Non linear least squares treatment of the potentiometric data indicates that in the concentration ranges: 0.5=C(A1)=2.0 ; 1.0=C(His)=10.0; 2.5=PH=6.5, in Al(3+) + His solutions, the following complexes (with log overall stability constants given in parenthesis) are formed: Al(HHis)(3+)(12.21+/-0.08); Al(His)(2+), (7.25+/-0.08); and Al(HHis)His(2+), (20.3+/-0.1). In Al(3+) + Tyr solutions in the concentration range 1.0=C(Tyr)=3.0 mmol/L and ligand to metal concentration ratio from 2:1 to 3:1, in the pH interval from 3.0 to 6.5 the formation of the following complexes was detected: Al(HTyr)(2+), (12.72+/-0.09); Al(Tyr)(2+), (10.16+/-0.03) and Al(OH)(2)Tyr , (2.70+/-0.05). Proton NMR data indicate that in Al(His)(2+) complex histidine acts as a monodentate ligand but its bidentate coordination is possible with carboxylate oxygen and imidazole 1-nitrogen as donors. In Al(HTyr)(3+) complex tyrosine is a monodentate ligand with carboxylate oxygen as donor. The mechanism of the formation of complexes in solution is discussed as well as their possible role in aluminum toxicity.
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http://dx.doi.org/10.1155/MBD.2002.235 | DOI Listing |
PLoS One
January 2025
Department of Mathematics, College of Natural and Computational Science, Debre Berhan University, Debre Berhan, Adis Ababa, Ethiopia.
Tuberculosis (TB) is one of the deadly infectious diseases affecting millions of individuals throughout the world. The main objective of this study is to investigate the impact of media coverage on the transmission dynamics of TB with vaccine and treatment strategy using mathematical model analysis. In the qualitative analysis of the proposed model we proved the existence, uniqueness, positivity, and boundedness of the model solutions, investigated both the disease-free and endemic equilibrium points, computed the basic and effective reproduction numbers using next generation matrix approach, analyzed the stability analysis of the equilibrium points, the backward bifurcation using the Castillo-Chavez and Song theorem and we re-formulated the corresponding optimal control problem and analyzed by applying the Pontryagin's Minimum Principle.
View Article and Find Full Text PDFMath Biosci Eng
December 2024
Department of Engineering and Natural Sciences, University of Applied Sciences Merseburg, Eberhard-Leibnitz-Str. 2, D-06217 Merseburg, Germany.
In this article, we reconsider the classical target cell limited dynamical within-host HIV model, solely taking into account the interaction between $ {\rm{CD}}4^{+} $ T cells and virus particles. First, we summarize some analytical results regarding the corresponding dynamical system. For that purpose, we proved some analytical results regarding the system of differential equations as our first main contribution.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China.
As a frontier of heterogeneous catalysis, single-atom catalysts (SACs) have been extensively studied fundamentally. One obstacle that limits the industrial application of SACs is the lack of a synthetic method that can prepare the catalysts on a large scale. Wet-chemistry methods that are conventionally used to prepare nanoparticle-based industrial catalysts might be a solution.
View Article and Find Full Text PDFSubcell Biochem
December 2024
IDIBE, Universidad Miguel Hernández, Elche, Alicante, Spain.
Nuclear magnetic resonance (NMR) is a spectroscopic technique based on the absorption of radiofrequency radiation by atomic nuclei in the presence of an external magnetic field. NMR has followed a "bottom-up" approach to solve the structures of isolated domains of viral proteins, including capsid protein subunits, or to provide information about other macromolecular partners with which such proteins interact. NMR has been instrumental in describing conformational changes in viral proteins and nucleic acids, showing the presence of dynamic equilibria which are thought to be important at different stages of the virus life cycle.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Mathematics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand.
In this paper, we propose an epidemic mathematical model with an impulsive vaccination strategy to predict outbreaks in chickens caused by vectors. The analysis of the model is divided into two parts: one considering impulsive vaccination and the other without it. We determine the basic reproduction number of disease transmission and analyze the stability conditions of the proposed model for both disease-free and endemic equilibria, addressing both local and global stability.
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