Numerical implementation and oceanographic application of the Gibbs potential of ice

The 2004 Gibbs thermodynamic potential function of naturally abundant water ice is based on much more experimental data than its predecessors, is therefore significantly more accurate and reliable, and for the first time describes the entire temperature and pressure range of existence of this ice phase. It is expressed in the ITS-90 temperature scale and is consistent with the current scientific pure water standard, IAPWS-95, and the 2003 Gibbs potential of seawater. The combination of these formulations provides sublimation pressures, freezing points, and sea ice properties covering the parameter ranges of oceanographic interest. This paper provides source code examples in Visual Basic, Fortran and C++ for the computation of the Gibbs function of ice and its partial derivatives. It reports the most important related thermodynamic equations for ice and sea ice properties

A meta-analysis of genome-wide data from five European isolates reveals an association of COL22A1, SYT1, and GABRR2 with serum creatinine level

<p>Abstract</p> <p>Background</p> <p>Serum creatinine (S_CR) is the most important biomarker for a quick and non-invasive assessment of kidney function in population-based surveys. A substantial proportion of the inter-individual variability in S_CRlevel is explicable by genetic factors.</p> <p>Methods</p> <p>We performed a meta-analysis of genome-wide association studies of S_CRundertaken in five population isolates ('discovery cohorts'), all of which are part of the European Special Population Network (EUROSPAN) project. Genes showing the strongest evidence for an association with S_CR(candidate loci) were replicated in two additional population-based samples ('replication cohorts').</p> <p>Results</p> <p>After the discovery meta-analysis, 29 loci were selected for replication. Association between S_CRlevel and polymorphisms in the collagen type XXII alpha 1 (<it>COL22A1</it>) gene, on chromosome 8, and in the synaptotagmin-1 (<it>SYT1</it>) gene, on chromosome 12, were successfully replicated in the replication cohorts (p value = 1.0 × 10^-6and 1.7 × 10^-4, respectively). Evidence of association was also found for polymorphisms in a locus including the gamma-aminobutyric acid receptor rho-2 (<it>GABRR2</it>) gene and the ubiquitin-conjugating enzyme E2-J1 (<it>UBE2J1</it>) gene (replication p value = 3.6 × 10^-3). Previously reported findings, associating glomerular filtration rate with SNPs in the uromodulin (<it>UMOD</it>) gene and in the schroom family member 3 (<it>SCHROOM3</it>) gene were also replicated.</p> <p>Conclusions</p> <p>While confirming earlier results, our study provides new insights in the understanding of the genetic basis of serum creatinine regulatory processes. In particular, the association with the genes <it>SYT1 </it>and <it>GABRR2 </it>corroborate previous findings that highlighted a possible role of the neurotransmitters GABA_Areceptors in the regulation of the glomerular basement membrane and a possible interaction between GABA_Areceptors and synaptotagmin-I at the podocyte level.</p

Computational Modeling of the Liquid Structure of Grossular Ca₃Al₂Si₃O₁₂ Glass-Ceramics

In this work, we present an atomistic model to simulate the structural and some thermodynamic properties of biomaterials as a test case of grossular glass-ceramics. The potential model used in our simulations included short range Born-Mayer type forces and long-range Coulomb interactions. We modelled the atomistic structure of grossular using the different structural optimization methods in conjunction with molecular dynamics simulations. The calculated values of the lattice constant, bulk modulus, elastic constants and cohesive energy are in reasonable agreement with experimental measurements and previous data. The melting point of grossular produced from a volume of the heating process is in a good agreement with literature. Comparison of the predictions of partial pair distribution functions and available experimental data shows that this model has simulated the liquid structure of grossular reasonably well

Thermodynamic Properties of Potassium Oxide (K₂O) Nanoparticles by Molecular Dynamics Simulations

Potassium oxide (K₂O) is a reagent for testing the presence of other compounds in chemical reactions. It is also used in compounding cement and in glass making. However properties of K₂O in nanoscale are still unclear. In this work, thermodynamic properties of spherical K₂O nanoparticles have been investigated. Size dependent cohesive energy, melting point and glass transition temperature have been computed for different sizes of K₂O nanoparticles by molecular dynamics simulations. Thermal expansion coefficients of nanoparticles at zero pressure and various temperatures have been also calculated. Melting point depression for K₂O nanoparticles was determined. The significant change in cohesive energy was obtained for particles smaller than 5.4 nm. The presented model is successful in understanding the size-dependent thermodynamics of spherical K₂O nanoparticles. Theoretical investigations of the thermal properties of K₂O nanoparticles have not been presented previously