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In this study, we investigate the impact of magnetic fields on the structural and thermodynamic properties of water. To accomplish this, we employed the Mercedes–Benz (MB) model, a two-dimensional representation of water using Lennard–Jones disks with angle-dependent interactions that closely mimic hydrogen bond formation. We extended the MB model by introducing two charges to enable interaction with the magnetic field. Employing molecular dynamics simulations, we thoroughly explored the thermodynamic properties concerning various magnetic flux intensities. As a result, we observed that under a weak magnetic flux, the property of water remained unaltered, while a stronger flux astonishingly led to the freezing of water molecules. Furthermore, our study revealed that once a specific flux magnitude was reached, the density anomaly disappeared, and an increase in flux caused the MB particles to form a glassy state.

DNA sequences that are rich in guanines and can form four-stranded structures are called G-quadruplexes. Due to the growing evidence that they may play an important role in several key biological processes, the G-quadruplexes have captured the interest of several researchers. G-quadruplexes may form in the presence of different metal cations as polymorphic structures formed in kinetically governed processes. Here we investigate a complex polymorphism of d(G4T4G3) quadruplexes at different K+ concentrations. We show that population size of different d(G4T4G3) quadruplex conformations can be manipulated by cooling rate and/or K+ concentration. We use a kinetic model to describe data obtained from DSC, CD and UV spectroscopy and PAGE experiments. Our model is able to describe the observed thermally induced conformational transitions of d(G4T4G3) quadruplexes at different K+ concentrations.

Linde type A (LTA) aluminophosphate is a promising candidate for an energy storage material used for low-temperature solar and waste-heat management. The mechanism of reversible water adsorption, which is the basis for potential industrial applications, is still not clear. In this paper, we provide mechanistic insight into various aspects of the hydration process using molecular modeling methods. Building on accurate DFT calculations and available experimental data, we first refine the existing empirical force-field used in subsequent classical molecular dynamics simulations that captures the relevant physics of the water binding process. We succeed in fully reproducing the experimentally determined X-ray structure factors and use them to estimate the number of water molecules present in the fully hydrated state of the material. Furthermore, we show that the translational and orientational mobility of the confined water is significantly reduced and resembles the dynamics of glassy systems.

The structures and properties of biomolecules like proteins, nucleic acids, and membranes depend on water. Water is also very important in industry. Overall, water is an unusual substance with more than 70 anomalous properties. The understanding of water is advancing significantly due to the theoretical and computational modeling. There are different kinds of models, models with fine-scale properties and increasing structural detail with increasing computational expense, and simple models, which focus on global properties of water like thermodynamics, phase diagram and are less computationally expensive. Simplified models give a better understanding of water in ways that complement more complex models. Here, we review analytical modelling of properties of water on different levels, the two- and three-dimensional Mercedes– Benz (MB) models of water and experimental water.

The viscosity of aqueous solutions of cesium fullerenehexamalonate Th-C 66(COOCs) 12, a rigid spherical nanometer-sized polyvalent salt, was measured by the Ubbelohde-type viscometer. The measurements were performed without added salt at 25 °C in the concentration range between 7 and 320 g/dm 3. THe concentration dependence of the obtained reduced viscosity was compared with the theoretical prediction, taking into account contributions stemming from the intrinsic viscosity, hydrodynamic perturbations of the hypothetically bare fullerenehexamalonate macroion, the primary electroviscous effect, and the secondary electroviscous effect. Using the geometric radius of the bare macroion from the previous measurements of the estimated effective charge of the macroion and from the small-angle X-ray scattering data of the estimated thickness of the compact shell of counterions electrostatically bound to the macroion, a good agreement between theory and the experiment was obtained in the range of the lowest and of the highest concentrations. Electrostatic interactions are identified as the main cause of the increased reduced viscosity at the lowest measured concentrations. At the highest concentrations, electrostatic interactions are effectively screened, and the influence of binary hydrodynamic interactions and perturbations of the hypothetical bare macroion prevails over electrostatic contributions to the increased viscosity. The electrophoretic mobility of the fullerenehexamalonate ion in aqueous salt-free medium was computed with the same value for the radius of the fullerenehexamalonate macroion as that used in the calculation of viscosity. The numerical solution of Ohshima’s equation agreed well with the experimental values. [ABSTRACT FROM AUTHOR]

Understanding the spatial folding of proteins from their amino acid sequences has an enormous potential in contemporary life sciences. The ability to predict secondary and tertiary structures from the primary through the use of computers will enable a much faster and more efficient discovery of organic substances with therapeutic or otherwise bioactive potential, largely eliminating the need for synthesis and testing of large numbers of organic substances for physiological effects. Our manuscript presents an application of correlation function analysis, usually used to describe properties of liquids, to protein structures in order to elucidate statistically favored distances among amino acids. Pairwise distribution functions were calculated between C-alpha atoms of 20 amino acids in a large ensemble of Protein Data Bank structures. The correlation functions show characteristic distances in amino acid interactions.

Methanol and water rank among the most important liquids in modern world due to their versatile use. As water, methanol and their mixture exhibit numerous anomalous properties, their description is challenging. Amphiphilic nature of methanol causes its aqueous solutions to have negative excess volume and enthalpy across entire composition range. Simple isotropic water model and its coarse-grained extension were used to study properties of methanol and water-methanol mixtures. Using Monte Carlo simulations, we showed that the model correctly describes the thermodynamic properties of methanol, ordering of water and methanol in mixtures, density dependence upon temperature and composition, and excess properties of mixtures. Although no conscious effort was made to fine-tune the potential, the results are remarkably close to experimental data.