EVALUATING OF EFFERVESCENT TABLETS CONTAINING GRAPE SEED (VITIS VINIFERA L.) EXTRACT AS A NUTRACEUTICAL

Objective: Grape is one of the most well-known fruits. People usually consume only the fruit and the skin; however, the seed is the part of the fruitthat contains important antioxidant rich polyphenol. However, grape seed and its extract have an unpleasant taste. Therefore, this study aimed toformulate effervescent tablets containing grape seed extract (GSE) to overcome the unpleasant taste.Methods: Effervescent tablets of GSE were formulated using three formulas, each with a different percentage of the effervescent mix. The tablets wereprepared using wet granulation method at 40% relative humidity (RH) (the ratio of the partial pressure of water vapor to the equilibrium vapor pressure ofwater) and 25°C temperature. The effervescent granules and the tablets were evaluated for various characteristics in term of granules flowability, moisturecontent, as well as tablets appearance, size and weight uniformity, hardness, friability, effervescence time, pH, and total phenol content. In addition, all threeformulations of the effervescent tablets and solutions were evaluated for appearance, taste, and flavor using the hedonic test that involved 30 panelists.Results: The evaluation of the effervescent granules and tablets showed that they had good characteristics. The disintegration time of the threeformulations was within the acceptable range, between 3.67 minutes and 4.69 minutes. The pH of the effervescent solution was between 5.18 and5.80. Based on the hedonic test, all the effervescent solutions had favorable appearance, taste, and flavor.Conclusions: Clinical Streptococcus salivarius isolates from the dorsum of the tongue had greater potential for inhibiting Enterococcus faecalis growthcompared to the saliva isolates and control bacteria. Therefore, we can conclude that the effervescent tablets containing grape seed extract arepotential be used as a nutraceutical dosage form.

Effect of Molecular Rotational Degrees of Freedom on Mechanical and Thermodynamic Properties of Solid Methane at Temperatures above 50 K

The paper presents an analysis of extensive data set of mechanical, structural, thermophysical, and spectral properties of solid methane in the temperature interval 0.5 · Ttr–Ttr (Ttr is the triple point temperature) under equilibrium vapor pressure. It is shown that the anomalies of the studied properties (or lack of reliable data) at temperatures 60–70 K have been observed in the body of the reviewed papers. We proposed that the observed anomalies are due to a transition between classical and quantum regimes of collective rotational degrees of freedom of methane molecules in this temperature interval.

Disjoining Pressure Effects in Ultra-Thin Liquid Films in Micropassages—Comparison of Thermodynamic Theory With Predictions of Molecular Dynamics Simulations

The concept of disjoining pressure, developed from thermodynamic and hydrodynamic analysis, has been widely used as a means of modeling the liquid-solid molecular force interactions in an ultra-thin liquid film on a solid surface. In particular, this approach has been extensively used in models of thin film transport in passages in micro evaporators and micro heat pipes. In this investigation, hybrid μPT molecular dynamics (MD) simulations were used to predict the pressure field and film thermophysics for an argon film on a metal surface. The results of the simulations are compared with predictions of the classic thermodynamic disjoining pressure model and the Born-Green-Yvon (BGY) equation. The thermodynamic model provides only a prediction of the relation between vapor pressure and film thickness for a specified temperature. The MD simulations provide a detailed prediction of the density and pressure variation in the liquid film, as well as a prediction of the variation of the equilibrium vapor pressure variation with temperature and film thickness. Comparisons indicate that the predicted variations of vapor pressure with thickness for the three models are in close agreement. In addition, the density profile layering predicted by the MD simulations is in qualitative agreement with BGY results, however the exact density profile is dependent upon simulation parameters. Furthermore, the disjoining pressure effect predicted by MD simulations is strongly influenced by the allowable propagation time of injected molecules through the vapor region in the simulation domain. A modified thermodynamic model is developed that suggests that presence of a wall-affected layer tends to enhance the reduction of the equilibrium vapor pressure. However, the MD simulation results imply that presence of a wall layer has little effect on the vapor pressure. Implications of the MD simulation predictions for thin film transport in micro evaporators and heat pipes are also discussed.

Disjoining Pressure Effects in Ultra-Thin Liquid Films in Micropassages: Comparison of Thermodynamic Theory With Predictions of Molecular Dynamics Simulations

The concept of disjoining pressure, developed from thermodynamic and hydrodynamic analysis, has been widely used as a means of modeling the liquid-solid molecular force interactions in an ultra-thin liquid film on a solid surface. In particular, this approach has been extensively used in models of thin film transport in passages in micro evaporators and micro heat pipes. In this investigation, hybrid μPT molecular dynamics (MD) simulations were used to predict the pressure field and film thermophysics for an argon film on a metal surface. The results of the simulations are compared with predictions of the classic thermodynamic disjoining pressure model. The thermodynamic model provides only a prediction of the relation between vapor pressure and film thickness for a specified temperature. The MD simulations provide a detailed prediction of the density and pressure variation in the liquid film, as well as a prediction of the variation of the equilibrium vapor pressure variation with temperature and film thickness. Comparisons indicate that the predicted variations of vapor pressure with thickness for these two models are in close agreement. A modified thermodynamic model is developed which suggests that presence of a wall-affected layer tends to enhance the reduction of the equilibrium vapor pressure. However, the MD simulation results imply that presence of a wall layer has little effect on the vapor pressure. Implications of the MD simulation predictions for thin film transport in micro evaporators and heat pipes are also discussed.