scholarly journals Biopolymeric materials containing brown algae polysaccharides

2017 ◽  
Vol 4 (2) ◽  
pp. 19
Author(s):  
Evgeniya V. Denisova ◽  
Viktoriya E. Suprunchuk ◽  
Anastasiya A. Dronova
Keyword(s):  
Synthetic Polymers ◽  
Water Molecules ◽  
Surface Films ◽  
High Ability ◽  
Polymeric Systems ◽  
Degree Of Swelling ◽  
Adsorption Of Water ◽  
Healing Of Wounds ◽  
Treatment Of Wounds ◽  
Biological Films

This article describes the use of polymeric systems created on the basis of natural or synthetic polymers. One of the most safe and biocompatible is fucoidan. Therefore, were proposed and developed the idea of creating films based on methylcellulose with fucoidan with the addition of various plasticizers. It was found that surface films affect the healing of wounds, as it causes the ability of the cells adhesion, the adsorption of water molecules. Also was investigated the physical properties of the films with different plasticizers, for example use as a plasticizer of the lactic acid allows to increase the capacity for swelling, as well as increase the ability to retain adsorbed, which is necessary for healing of wounds after burns. The use of glycerin or propylene glycol resulted in a decrease in the degree of swelling, and the absence of the plasticizer contributes to enhancement of the adsorption of water molecules. Data from biological films possess high ability to swell, and therefore not only applicable for the treatment of wounds with lots of exudate, but due to the high holding capacity applicable for low exudative wounds.

A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

2018 ◽  
Author(s):  
Kyle Reeves ◽  
Damien Dambournet ◽  
Christel Laberty-Robert ◽  
Rodolphe Vuilleumier ◽  
Mathieu Salanne
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Water Dissociation ◽  
Water Molecules ◽  
Chemical Doping ◽  
Charge Balance ◽  
Functional Theory ◽  
Adsorption Of Water ◽  
Properties Of Materials ◽  
Computational Comparison

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO<sub>2</sub> with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a<br>monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the<br>variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in<br>the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

A First-Principles Computational Comparison of the Aqueous Anatase TiO2 (001) Interface and the Disordered, Fluorinated TiO2 Interface

2018 ◽  
Author(s):  
Kyle Reeves ◽  
Damien Dambournet ◽  
Christel Laberty-Robert ◽  
Rodolphe Vuilleumier ◽  
Mathieu Salanne
Keyword(s):  
Density Of States ◽  
Density Functional ◽  
Water Dissociation ◽  
Water Molecules ◽  
Chemical Doping ◽  
Charge Balance ◽  
Functional Theory ◽  
Adsorption Of Water ◽  
Properties Of Materials ◽  
Computational Comparison

Chemical doping and other surface modifications have been used to engineer the bulk properties of materials, but their influence on the surface structure and consequently the surface chemistry are often unknown. Previous work has been successful in fluorinating anatase TiO<sub>2</sub> with charge balance achieved via the introduction of Ti vacancies rather than the reduction of Ti. Our work here investigates the interface between this fluorinated titanate with cationic vacancies and a<br>monolayer of water via density functional theory based molecular dynamics. We compute the projected density of states for only those atoms at the interface and for those states that fall within 1eV of the Fermi energy for various steps throughout the simulation, and we determine that the<br>variation in this representation of the density of states serves as a reasonable tool to anticipate where surfaces are most likely to be reactive. In particular, we conclude that water dissociation at the surface is the main mechanism that influences the anatase (001) surface whereas the change in<br>the density of states at the surface of the fluorinated structure is influenced primarily through the adsorption of water molecules at the surface.

Biopolymers with Medical Applications Optimized method for obtaining chitosan-based delivery systems

2018 ◽  
Vol 69 (7) ◽  
pp. 1756-1759 ◽  
Author(s):  
Luminita Confederat ◽  
Iuliana Motrescu ◽  
Sandra Constantin ◽  
Florentina Lupascu ◽  
Lenuta Profire
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Average Diameter ◽  
Delivery Systems ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Polymeric Systems ◽  
Chitosan Microparticles ◽  
Degree Of Swelling

The aim of this study was to optimize the method used for obtaining microparticles based on chitosan � a biocompatible, biodegradable, and nontoxic polymer, and to characterize the developed systems. Chitosan microparticles, as drug delivery systems were obtained by inotropic gelation method using pentasodiumtripolyphosphate (TPP) as cross-linking agent. Chitosan with low molecular weight (CSLMW) in concentration which ranged between 0.5 and 5 %, was used while the concentration of cross-linking agent ranged between 1 and 5%. The characterization of the microparticles in terms of shape, uniformity and adhesion was performed in solution and dried state. The size of the microparticles and the degree of swelling were also determined. The structure and the morphology of the developed polymeric systems were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The average diameter of the chitosan microparticles was around 522 �m. The most stable microparticles were obtained using CSLMW 1% and TPP 2% or CSLMW 0.75%and TPP 1%. The micropaticles were spherical, uniform and without flattening. Using CSLMW in concentration of 0.5 % poorly cross-linked and crushed microparticles have been obtained at all TPP concentrations. By optimization of the method, stable chitosan-based micropaticles were obtained which will be used to develop controlled release systems for drug delivery.

scholarly journals The structure of surface films. Part XVI.—Surface potential measurements on fatty acids on dilute hydrochloric acid

1932 ◽  
Vol 138 (835) ◽  
pp. 411-430 ◽  
Keyword(s):  
Fatty Acids ◽  
Dipole Moment ◽  
Dilute Hydrochloric Acid ◽  
Vertical Component ◽  
Water Molecules ◽  
Surface Films ◽  
Pressure Measurements ◽  
Contact Potential ◽  
Surface Potential Measurements ◽  
Air Liquid Interface

Guyot, Frumkin, and Schulman and Rideal have shown that it is possible, by means of an air electrode covered with a small amount of a radioactive deposit, which ionises the air in its neighbourhood, to measure changes in the contact potential at an air-liquid interface caused by spreading a film over the surface. It is now clear that this change in contact potential is caused by the dipoles of the film molecules, the magnitude of the change in potential depending on the vertical component of the dipole moment of the molecules in the film, and on the extent to which the water molecules and the ions in the solution are re-arranged near the surface under the influence of these dipoles. In combination with surface pressure measurements, which have already given a great deal of information as to the orientation of the molecules in the surface, and their shapes, sizes, and adhesive fields of force, this method, which indicates the orientation of the dipoles of the film molecules to the surface, is a valuable addition to our methods of investigating the structure of surface films.

scholarly journals Adsorption of Water Molecules on Pristine and Defective NiPX 3 (X: S, Se) Monolayers

2021 ◽  
pp. 2100182
Author(s):  
Zhicheng Wu ◽  
Sifan Xu ◽  
Yong Zhou ◽  
Qilin Guo ◽  
Yuriy Dedkov ◽  
...  
Keyword(s):  
Water Molecules ◽  
Adsorption Of Water
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