An in vivo study of the healing properties of the glycerohydrogel plates based on
L
- and
D
-ascorbate chitosan,
Aloe vera
juice, and silicon tetraglycerolate in the treatment of a cut wound in male ...albino rats was carried out. It was found that the use of the plates statistically significantly increased the rate of decrease in the area of the wound surface and the rate of wound healing and reduced the period of skin restoration as compared with the control. The highest rate of regeneration was observed under plates with chitosan
D
-ascorbate, which confirmed the previously discovered effect of homochirality of chitosan salts on the biological functionality of its materials. Glycerohydrogel plates based on
D
-ascorbate chitosan are highly effective wound dressings and are economically feasible due to the lower cost of the
D
isomer of ascorbic acid.
A technique for analyzing new corrosion-resistant ruthenium-doped titanium alloys using inductively coupled plasma atomic emission spectrometry (ICP-AES) with microwave sample preparation is ...reported. The composition of a mixture of acids and the temperature and time parameters of sample preparation of titanium alloys under microwave heating in an autoclave ensuring quantitative conversion of the sample into a convenient analytical form without loss of volatile components for subsequent ICP-AES analysis are substantiated. Optimal conditions for the excitation of the analytical signal have been found, and analytical lines of elements without spectral noise have been selected. Samples of experimental melts of industrial titanium alloys of various classes, volumetrically doped with ruthenium, which are under development and are not yet commercially produced in the Russian Federation (alloy PT-7M + Ru, PT-3B + Ru, 5B + Ru, 37 + Ru, VT-22 + Ru) have been studied. The alloy samples contained the following alloying elements (wt %): Al (1.8–6.3); V (1.0–5.5); Mo (0.7–5.5); Zr (0.2–3.0); Cr (0.5–1.5); Fe (0.5–1.5); Ru (0.05–0.15). The correctness of the determination of alloying elements has been confirmed by analyzing standard samples by varying their mass and, in the case of ruthenium, by the “introduced–found” method. The developed method significantly reduces the time of analysis by combining the multielement ICP-AES method with microwave sample preparation, expands the list of detectable elements in titanium alloys, and improves the precision of the results of analysis.
In our previous studies, it was shown that the isomeric form of ascorbic acid (L-or D-AscA) used to obtain the salt form of chitosan had a significant effect on the total space charge, size and ...general chirality of chitosan ascorbate macromolecules in solution, their stereomeric ordering in lyophilically isolated solid phase, as well as the kinetics of sol-gel synthesis of materials based thereon. This study examines the effect of L- and D-AscA on the physico-mechanical and morphological properties of thin-film sol-gel plates based on chitosan L-or D-ascorbate without and with Aloe Vera juice added. It has been established that the AscA isoform has a significant effect on the elastoplastic characteristics of the samples and the surface relief of their solid phase. The addition of Aloe Vera also leads to significant texturing of the surface relief. The latter could be used to design specific optical sensors and optodes of medico-biological purposes.
The influence of the chirality of chitosan ascorbate on the gelation kinetics and the properties of hybrid silicon-chitosan-containing glycerohydrogels were studied with a deep estimation of the ...stereospecificity of chitosan polysalts with l- and d-ascorbic acid diastereomers and their biological effects. It has been established that l- and d-diastereomerically enriched chitosan ascorbates are characterized by a positive Cotton effect and differ in the wavelength of the maximum of the dichroic band (250 and 240 nm), as well as in the values of its specific ellipticity (21.8 × 10⁵ and 39.2 × 10⁵ deg·mL·dm
·g
), the sign of specific optical rotation (+ and -), the type of dispersion curves (anomalous and smooth), as well as the condensed phase morphology (anisodiametric particles with optical anisotropy and confocal domains of spherical shape, respectively). In the biomimetic sol-gel synthesis of silicon-chitosan-containing glycerohydrogels using silicon tetraglycerolate as a precursor, it was found that chitosan d-ascorbate retarded gelation. Thin congruent plates obtained from the corresponding glycerohydrogels based on chitosan d-ascorbate have higher mechanical strength and elasticity under uniaxial stretching and lower values of Young's modulus. It has been shown that the systems based on chitosan d-ascorbate show the greatest antibacterial activity against
209P and
113-13 and significantly promote the viability of normal human dermal fibroblasts. The results of our assessment of the biological properties of chitosan polysalts are unexpected, since ascorbic acid exhibits biological activity as its l-isomer only.
The structure of deformed semifinished products (forgings) from titanium alloys of Ti–Al–Zr + 0.15% Ru, Ti–Al–V–Mo + 0.15% Ru, and Ti–Al–V–Cr–Fe–Mo + 0.15% Ru systems has been investigated. The basic ...mechanical properties, microstructure, results of local elemental and phase analyses obtained by X-ray spectral microanalysis and backscattered electron diffraction, and also a model of the effect of ruthenium on increasing corrosion resistance of titanium alloys of various classes are presented.
This article discusses test results of corrosion mechanical properties and fatigue properties of deformed semifinished items (forgings and pipes) made of titanium alloys PT-7M and PT-7M with addition ...of ruthenium. The main mechanical properties of titanium alloys, the structure, and the ruthenium distribution in the structure are determined. Results of static three-point bending tests of specimens with crack are discussed for determination of corrosion mechanical strength and cyclic fatigue strength of forgings and pipes of these alloys in a corrosive medium.
—This article discusses the results of corrosion tests and microstructural studies of forgings from various titanium alloys modified with ruthenium, of systems Ti–Al–Zr + 0.15% Ru, Ti–Al–V–Mo + 0.15% ...Ru, and Ti–Al–V–Cr–Fe–Mo + 0.15% Ru and similar systems of basic compositions. On the basis of the performed complex of studies, the influence of the amount of the β phase on the local content of ruthenium and, as a consequence, on the effect of cathodic protection in general is analyzed.
The investigation is focused on the study of the structure, fracture, and phase composition of standard industrial pseudo-alpha-titanium alloy and the same titanium alloy alloyed with ruthenium. ...Also, the possibility to increase the low-cycle fatigue and resistance to stress corrosion cracking of industrial titanium allow using cathodic alloying with ruthenium.
The effect of the chiosan ascorbate chirality on its structural features in solution and in the solid state was studied using optical rotation dispersion and scanning electron microscopy. It has been ...established that the isomeric form of ascorbic acid has a significant impact on the stereomeric ordering of chiral chitosan ascorbate macromolecules in solution and solid-phase supramolecular structures isolated therefrom.
The
necessity
of systematic formation of intellectual connections for integration into a single complex of currently fragmented software products for the technological analysis of the castings ...geometry, thermodynamic modeling of the titanium alloys properties, calculation of molding mixtures thermophysical characteristics for the purpose of conjugate implementation of a set of modeling procedures and casting processes diagnostics of is proved. Lack of such an integrated software package, computer analysis of modeling results in the existing manufacturing products practice demonstrates (by the example of the shrinkage defects distribution in a responsible casting of TL3 alloy) the need for radical technological design tools’ improvement.
One
of the key components of the “digital technology” being formed in the future is thermodynamic modeling of equilibrium phase transformations, which allows calculating the physico-chemical parameters, thermodynamic, thermophysical and casting parameters of titanium alloys and their evolution in the temperature range of crystallization. Based on thermodynamic simulation, experimental planning apparatus and the experience of statistical analysis carried out, a method for forming models for estimating equilibrium parameters used in modeling foundry processes has been developed, and it shows the possibility of applying it to various casting titanium alloys. For the standard composition of the TL3 alloy, a multifactor system of equations was obtained, reflecting the degree of influence of the components on the fluctuations of the alloy characteristics complex, which determine the development of a series of casting defects. The possibilities of using the obtained models for TL3 alloy and methods of obtaining them for use in computer modeling systems to increase the adequacy and accuracy of the results obtained are described.
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