Effects of physical and chemical properties on the dissolution of sea salt

Salt plays a crucial role in human health. However, excess use of NaCl in food products can be harmful to health. One suggestion for this problem is optimization salt dissolution to increase the content of salt ions in the mouth. For this purpose, it is important to understand the solubility properties of salt crystals in saliva. The dissolving process is not only affected by the physical properties but also by the chemical composition of the salt. This study compared the solubility of four commercial grain salts in four regions in Vietnam (Bac Lieu, Thanh Hoa, Sa Huynh, Vung Tau), one flower salt in Sa Huynh and a control sample with two particle sizes 1 - 2 mm and 2 - 3 mm in a Saliva Artificial Gal – Fovet solution (SAGF). Dissolution was determined by analyzing microscopic images taken by the time and analysis by Bayesian and Partial Least Squared methods. The research evaluated the influence of physical properties (area, Feret's diameter, circularity, aspect ratio and solidity) and chemical compositions (sodium, potassium, magnesium, calcium and moisture content) on the dissolving process. Salt samples showed significant differences in physical and chemical properties by region. Morphological parameters are affected by conditions of salt crystallization that indicated through region of origin. Dissolution is evaluated through solubility coefficient, Sa Huynh flower salt and control salt have the highest solubility coefficient, simultaneously, it is also the smallest value of roundness and surface index. The projected area, magnesium and sodium content are the factors which strongly affecting on dissolution of salt samples. These results demonstrated the possibility to exploit these factors to adjust the solubility of salt as well as the perceived salinity over time.

Ectothermy and cardiac shunts profoundly slow the equilibration of inhaled anaesthetics in a multi-compartment model

The use of inhalational anaesthesia is ubiquitous in terrestrial vertebrates. Given the dependence of these agents on delivery by the cardiorespiratory system, we developed a new computational model predicting equilibration of inhaled anaesthetics in mammalian and ectotherm conditions including the ability of reptiles to maintain vascular shunts. A multi-compartment model was constructed from simultaneously-solved equations, verified by comparison to the literature for endo and ectotherm physiology. The time to 90% equilibration of anaesthetic in arterial blood (t90) is predicted and used to compare anaesthetics and physiologies. The five to tenfold lower cardiac output and minute ventilation of ectothermic vertebrates is predicted to slow equilibration times by five to ten times leading to 90% equilibration in ectotherm arterial blood of over 200 min, compounded by reduction in body temperature, and the extent of right-to-left vascular shunts. The impact of these findings is also influenced by the solubility coefficient of the anaesthetic, such that at net right-to-left shunt fractions of over 0.8, sevoflurane loses the advantage of faster equilibration, in comparison with isoflurane. We explore clinical strategies to regulate anaesthetic uptake in ectotherms by managing convectional flow especially by supportive ventilation and reduction of the right-to-left shunt.

Development and Validation of a Virtual Gelatin Model Using Molecular Modeling Computational Tools

To successfully design and optimize the application of hydrogel matrices one has to effectively combine computational design tools with experimental methods. In this context, one of the most promising techniques is molecular modeling, which requires however accurate molecular models representing the investigated material. Although this method has been successfully used over the years for predicting the properties of polymers, its application to biopolymers, including gelatin, is limited. In this paper we provide a method for creating an atomistic representation of gelatin based on the modified FASTA codes of natural collagen. We show that the model created in this manner reproduces known experimental values of gelatin properties like density, glass-rubber transition temperature, WAXS profile and isobaric thermal expansion coefficient. We also present that molecular dynamics using the INTERFACE force field provides enough accuracy to track changes of density, fractional free volume and Hansen solubility coefficient over a narrow temperature regime (273–318 K) with 1 K accuracy. Thus we depict that using molecular dynamics one can predict properties of gelatin biopolymer as an efficient matrix for immobilization of various bioactive compounds, including enzymes.

Molecular Simulation of Solution Process of Organic Molecules in Polyethylene Membranes

The dissolution process of benzene, toluene and ethylbenzene in amorphous polyethylene (PE) membrane was studied in this paper, and the solubility coefficients of the above organic molecules were analyzed and calculated by molecular dynamics simulation. The results showed: the solubility coefficient decreased with increasing molecular weights of organic molecules in the same temperature, and it also decreased with increasing temperature for the same organic molecule. Distribution of density field and energy field for organic molecules in PE were obtained. From the density distribution, the concentrated adsorbed area of the three kinds of molecules is clearly seen, which located at the more loose place in polyethylene membrane. From the energy distribution, it showed thehot spots of the organic molecules, which were the location that the organic molecules were most easily absorbed. The adsorption capacities of benzene, toluene and ethyl benzene in polyethylene membrane decreased in turn.

Analytical Dependence of Substance Solubility Measure on Temperature

The work covers an adequate analytical dependence of solubility measure of the chemical substances on the water/aqueous solution temperature. The solubility was defined and new, more readable solubility measure was introduced; the coefficient of solubility has been proposed instead. Then the source differential equation was introduced as the basis for the derivation of a final analytical form of dependence of the solubility coefficient on temperature. That characteristics has been developed by determining the dependence of the solubility coefficient variability intensity on temperature. An example of the use of presented theory has been delivered by referring it to the phenomenon of dissolution of AgNO3 silver nitrate in the aqueous environment. In the summary, quite a developed use of the source differential equation has been underlined with some more examples revealed.