The oxidation and reduction that occur during early diagenesis of sediments has been studied in the interstitial waters of a rapidly accumulating sedimentary sequence from the Mediterranean margin of Spain. A series of reactions that are mediated by progressively lower free energy derived from oxidation of organic matter is evident in the sedimentary sequence. Iron and manganese are rapidly red...

2014 In order to account for experimentally observed qualitative properties of random field Ising systems, a new picture of transitions in systems with frozen disorder is suggested. According to this picture, equilibration processes near Tc require activated jumps between remote free energy wells in the phase space. These jumps involve very slow dynamics, described by a modified Vogel-Fulcher l...

Historical interpretations of the thermodynamics characterizing biomolecular recognition have marginalized the role of water. An important (even, perhaps, dominant) contribution to molecular recognition in water comes from the “hydrophobic effect,” in which non-polar portions of a ligand interact preferentially with non-polar regions of a protein. Water surrounds the ligand, and water fills the...

Ionic electrodiffusion and osmotic water flow are central processes in many physiological systems. We formulate a system of partial differential equations that governs ion movement and water flow in biological tissue. A salient feature of this model is that it satisfies a free energy identity, ensuring the thermodynamic consistency of the model. A numerical scheme is developed for the model in ...

Molecular Dynamics (MD) simulations have been performed on a series of mutants of the 20 amino acid peptide Betanova in order to critically assess the ability of MD simulations to reproduce the folding and stability of small β-sheet forming peptides on currently accessible time scales. Simulations were performed in both water and in 40% methanol solution using an explicit solvent model. The sim...

Accurate and reliable pKa prediction is of significant interest, because it provides direct information of the protonation state of a protein and can be compared to experimental data. In this work pKa shifts of three aminoacids in proteins have been calculated using molecular dynamics free energy simulations with an explicit solvent and implicit Generalized Born solvent model. The direction of ...

The accurate prediction of absolute protein-ligand binding free energies is one of the grand challenge problems of computational science. Binding free energy measures the strength of binding between a ligand and a protein, and an algorithm that would allow its accurate prediction would be a powerful tool for rational drug design. Here we present the development of a new method that allows for t...

certain gases, principally oxygen,o , and carbon dioxide, co , dissolved in water accelerate its corrosive properties. the rate of corrosion is approximately in prportion to the quantity of gas dissolved. the removal of gases from water, as practiced in steam station, is effected by mechanical and thermal treatment , by addition of chemicals, or by combinations of these processes, the most wide...

Use of drinking water sold in plastic bags (sachet water) is growing rapidly in west Africa. The impact on water consumption and child health remains unclear, and a debate on the taxation and regulation of sachet water is ongoing. This study assessed the feasibility of providing subsidized sachet water to low-income urban households in Accra and measured the resultant changes in water consumpti...