Electrodialysis Tartrate Stabilization of Wine Materials: Fouling and a New Approach to the Cleaning of Aliphatic Anion-Exchange Membranes

Electrodialysis (ED) is an attractive method of tartrate stabilization of wine due to its rapidity and reagentlessness. At the same time, fouling of ion-exchange membranes by the components of wine materials is still an unsolved problem. The effect of ethanol, polyphenols (mainly anthocyanins and proanthocyanidins) and saccharides (fructose) on the fouling of aliphatic ion-exchange membranes CJMA-6 and CJMC-5 (manufactured by Hefei Chemjoy Polymer Materials Co. Ltd., Hefei, China) was analyzed using model solutions. It was shown that the mechanism and consequences of fouling are different in the absence of an electric field and during electrodialysis. In particular, a layer of colloidal particles is deposited on the surface of the CJMA-6 anion-exchange membrane in underlimiting current modes. Its thickness increases with increasing current density, apparently due to the implementation of a trap mechanism involving tartaric acid anions, as well as protons, which are products of water splitting and “acid dissociation”. A successful attempt was made to clean CJMA-6 in operando by pumping a water-alcohol solution of KCl through the desalination compartment and changing electric field direction. It has been established that such a cleaning process suppresses the subsequent biofouling of ion-exchange membranes. In addition, selective recovery of polyphenols with high antioxidant activity is possible

Application of multi-layer chitosan-based wound dressings in dentistry

Aim. To experimentally evaluate the efficacy of multi-layer chitosan-based wound dressings developed for dental purposes.Materials and Methods. Over the period from 2018 to 2019, an experimental study was conducted to evaluate the efficacy of multi-layer chitosan-based wound dressings developed for dental practice. Two types of dressings (No. 1c and 2c), the central part of which was modified with the introduction of a 10% iodopyron solution, were compared with the widely-used wound dressings Alvostaz (NKF Omega-Dent LLC, Russia) and Gelatamp (Roeko, Germany). The work involved 26 male Chinchilla rabbits, ten months old and weighing 2500 (±50) g. Evaluation of the efficacy of the wound dressings under study was carried by modelling the conditions of both aseptic and purulent-inflammatory processes (a total of 8 series of experiments). In experiments modelling the purulent-inflammatory process, a Ps. aeruginosa bacterial culture at a concentration of 109 CFU/ml was introduced into the alveolar socket after tooth extraction, 3 days before the application of a wound dressing sample. The dressings under study were applied on the wound for the period of 7 days. During the observation postoperative period, the animals were provided with free access to water and food. The sampling of the material for the study was carried out in the operating room on day 7.Results. According to the experimental results, chitosan-based wound dressings (No. 2c in particular) demonstrated high efficacy in experiments on animals (rabbits). The developed wound dressings perform mechanical protection and exhibit fuse effects, as well as are characterized by biodegradability and the ability to deliver medical agents contained therein to the damaged tissue.Conclusion. The proposed chitosan-based wound dressings showed sufficient efficiency on the modelled wound process in the alveolar socket of an extracted tooth. Dressing No. 2c was recognised to be optimal for infected and purulent wounds. This dressing has a dense outer layer, which structure retains frame functions for a long time, thus providing proper drainage of the pathological focus. Dressing No. 1c was established to be promising in cases without inflammatory processes in the extracted tooth socket, where high adhesion to surrounding tissues is initially required for ensuring the tightness and preservation of a blood clot in the wound