Structure and properties of starch - BaSO4 composite obtained using mechanical activation techniques.

The aim of this study is to obtain and characterize starch films structurally modified by in situ precipitation of BaSO4 combined with mechanical activation of casting dispersion in a rotor-stator device. By the rheological method, it was found that the modification causes a decrease in the ability of casting dispersions to structure over time. Composite films with a filler content of 0 %-15 % (w/w) were characterized using optical and SEM microscopy, FT-IR spectroscopy, and tensile and moisture resistance testing data. The maximum increase in strength (by 70 %) and elongation at break (by 870 %) is achieved with a filler content of 5 % and 15 %, respectively. An increase in the filler content to 5 % causes an increase in starch recrystallization rate, but at concentrations above 5 % of BaSO4, it inhibits retrogradation. The films obtained by mechanical activation with optimized parameters were uniformly translucent, had lower water vapor permeability than films made from starch alone, had high flexibility, and did not warp or shrink. The developed high-performance, environmentally friendly method can be recommended for the large-scale production of starch-based composite materials.

Effect of composition and mechanoactivation on the properties of films based on starch and chitosans with high and low deacetylation.

The effect of composition and mechanoactivation in the rotor-stator device on the rheological and film-forming properties of casting blends based on corn starch and chitosans with high (HDC) and low (LDC) deacetylation degree was studied. Films were characterized using optical and atomic force microscopy, X-ray diffraction, FTIR-spectroscopy and by tensile and moisture permeability testing data. An increase in chitosan content was found to result in the blends viscosity increase as well as the tensile strength, elongation and moisture permeability of films. Mechanoactivation was shown to cause an increase in the homogeneity, smoothness and transparency of the films, and an increase in the tensile strength by 1.5 and 2.5 times for the HDC and LDC based films, respectively. It is concluded that the developed eco-friendly and easily implemented method, which allows improving the unsatisfactory properties of starch-chitosan films without the introduction of additional chemicals, can be used on an industrial scale.

The influence of the combined impact of shear stress and cavitation on the structure and sorption properties of chitin.

In this work, we studied the structural, morphological and chemical transformations in α- chitin, caused by its mechanical activation in the form of an aqueous suspension in the rotor-stator device for 5-30 s. Mechanically activated chitin (MA-chitin) was characterized using optical and electron scanning microscopy, N2 adsorption/desorption isotherms, X-ray diffraction and FTIR-spectroscopy. It was established that the specific surface area, porosity and the deacetylation degree of chitin increase with increasing processing time, and the decrease in crystallinity and reducing the packing density of macromolecular chains does not correlate with this indicator due to the development of recrystallization. The efficiency of chitin activation was evaluated by studying its ability to adsorb anionic and cationic dyes. It was found that the limiting adsorption capacity of MA-chitin was on average 2-4 times higher, and the time to reach equilibrium was, on average, 3-4 times less compared to raw chitin.

[Cardiac syndrome in females with systemic undifferentiated dysplasia of the connective tissue]. / Sindrom porazheniia serdtsa u zhenshchin s sistemnoi nedifferentsirovannoi displaziei soedinitel'noi tkani.

The trial enrolled 119 women with systemic undifferentiated dysplasia of the connective tissue (DCT) aged 14-39 years; 86.6% of them had asthenic constitution. Ultrasound most frequently found prolapse of mitral cusps and accessory chord as in the left ventricle. Use of chest x-ray, echocardiography, ECG 24-h monitoring and transesophageal pacing discovered combination of heart dislocation, changed intracardiac structures, disturbed rhythm and conduction in 87 examinees. This provided the diagnosis of dysplastic heart syndrome. Multiple significant correlations between echocardiometric parameters, hormonal indices, neuroendocrine disorders, reproductive disorders point to close relations between cardiovascular and neuroendocrine systems in women with DCT.

[Neuroendocrine dysfunction in female patients with systemic dysplasia of the connective tissue]. / Neiroéndokrinnaia difunktsiia u zhenshchin s sistemnoi displaziei soedinitel'noi tkani.

The study covered 119 women with systemic undifferentiated dysplasia of the connective tissue (DCT) aged 14-39 years. All the examinees had vegetative disorders, 26.1% had a neuroendocrine-metabolic form of hypothalamic syndrome (HS), 51.3%--premenopausal syndrome, 65.5%--dysmenorrhea. It was found that women with DCT and HS develop symptoms of neuroendocrine disorders at earlier age than those with HS but free of DCT. Arterial hypertension was registered in 96.8% of patients with DCT and HS, 80.3% of DCT patients with premenopausal syndrome. Central hemodynamics was different in DCT patients without neuroendocrine disorders and with neuroendocrine dysfunction evidencing the role of the latter in development of arterial hypertension in DCT.