Preparation and characterization of wound healing hydrogel based on fish skin collagen and chitosan cross-linked by dialdehyde starch.

Hydrogels due to high water absorption capacity, flexibility, biodegradability properties and also the ability to provide a moist environment, same as native extracellular, are widely used for wound healing applications. Developing multifunctional hydrogels using biomaterial is an emerging approach in this area. Collagen and chitosan are known as excellent biomaterials due to their properties, functionality, and sustainable sources. They also have good biocompatibility and biodegradability, suitable for wound healing hydrogels. In this study, the physicochemical characterization, morphology, and biocompatibility of collagen/chitosan/ dialdehyde starch hydrogel (Col/Ch/DAS) were evaluated. Type I collagen was extracted from silver carp skin by-product. DAS was synthesized by a one-step method of acid hydrolysis and oxidation. Hydrogels were made from collagen (4 % w/v) and chitosan mix (2 % w/v) and added DAS (2 % w/v) (0.5, 1.0 and 1.5 ml) as a cross-linker to enhance the physicochemical behaviors of the hydrogels. Swelling ratio, biodegradation, water vapor transmission rate (WVTR), surface morphology and the interactions between functional groups of polymers used in the hydrogel were evaluated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test of extracted collagen indicated the presence of two different α-chains in collagen and confirmed type I collagen. The results showed that DAS content significantly affected the swelling ratio and biodegradability of hydrogels (P < 0.05). Col/Ch/Das0.5 hydrogel showed the highest swelling and biodegradability compared to other hydrogels (P < 0.05). Col/Cs/DAS hydrogels showed suitable water vapor transmission for wound dressing. The Fourier transform infrared spectroscopy (FTIR) results showed that covalent bonds formed via acetalization and Schiff base reaction. The results suggested that the prepared hydrogel from silver carp fish skin collagen has excellent potential as a new wound dressing for medical and biomedical applications such as wound healing.

Pattern Classification of Hand Movement Tremor in MS Patients with DBS ON and OFF.

BACKGROUND: Hand tremor is one of the consequences of MS disease degrading quality of patient's life. Recently DBS is used as a prominent treatment to reduce this effect. Evaluation of this approach has significant importance because of the prevalence rate of disease. OBJECTIVE: The purpose of this study was the nonlinear analysis of tremor signal in order to evaluate the quantitative effect of DBS on reducing MS tremor and differentiating between them using pattern recognition algorithms. MATERIAL AND METHODS: In this analytical study, nine features were extracted from the tremor signal. Through statistical analysis, the significance level of each feature was examined. Finally, tremor signals were categorized by SVM, weighted KNN and NN classifiers. The performance of methods was compared with an ROC graph. RESULTS: The results have demonstrated that dominant frequency, maximum amplitude and energy of the first IMF, deviation of the direct path, sample entropy and fuzzy entropy have the potential to create a significant difference between the tremor signals. The classification accuracy rate of tremor signals in three groups for Weighted KNN, NN and SVM with Gaussian and Quadratic kernels resulted in 95.1%, 93.2%, 91.3% and 88.3%, respectively. CONCLUSION: Generally, nonlinear and nonstationary analyses have a high potential for a quantitative and objective measure of MS tremor. Weighted KNN has shown the best performance of classification with the accuracy of more than 95%. It has been indicated that DBS has a positive influence on reducing the MS tremor. Therefore, DBS can be used in the objective improvement of tremor in MS patients.