Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains. © 2016 Elsevier B.V. All rights reserved

Исследование кислого (тетракапролактам) додекамолибдосиликата состава (C₆H₁₁NO)_4.5Н₄[SiМо₁₂O₄₀]

New caprolactam dodecamolybdosilicate of the composition (C6H11NO)4.5Н4 [SiМо12O40] (I) is synthesized. Chemical and crystallographic analyses, NMR and IR spectroscopic studies are performed. Compound I is found to crystallize in the monoclinic system with the space group P 21/ n. Unit cell parameters are: a = 19.945(4), b = 13.340(3), c = 28.110(6) Å, b = 110.75(3)°, rcalc = 2.232 g/cm3, М = 2350.63, Z = 4, V = 6994(3) Å3.Синтезирован новый додекамолибдосиликат капролактама состава (C6H11NO)4.5Н4·[SiМо12O40] (I). Проведен химический, рентгеноструктурный анализ, ЯМР и ИК-спектроскопическое исследование. Установлено, что соединение I кристаллизуется в моноклинной сингонии в пространственной группе P 21/ n. Параметры элементарной ячейки: a = 19.945(4), b = 13.340(3), c = 28.110(6) Å, β = 110.75(3)°, ρвыч = 2.232 г/см3, М = 2350.63, Z = 4, V = 6994(3) Å3

Исследование кислого (тетракапролактам) додекамолибдосиликата состава (C₆H₁₁NO)_4.5Н₄[SiМо₁₂O₄₀]

New caprolactam dodecamolybdosilicate of the composition (C6H11NO)4.5Н4 [SiМо12O40] (I) is synthesized. Chemical and crystallographic analyses, NMR and IR spectroscopic studies are performed. Compound I is found to crystallize in the monoclinic system with the space group P 21/ n. Unit cell parameters are: a = 19.945(4), b = 13.340(3), c = 28.110(6) Å, b = 110.75(3)°, rcalc = 2.232 g/cm3, М = 2350.63, Z = 4, V = 6994(3) Å3.Синтезирован новый додекамолибдосиликат капролактама состава (C6H11NO)4.5Н4·[SiМо12O40] (I). Проведен химический, рентгеноструктурный анализ, ЯМР и ИК-спектроскопическое исследование. Установлено, что соединение I кристаллизуется в моноклинной сингонии в пространственной группе P 21/ n. Параметры элементарной ячейки: a = 19.945(4), b = 13.340(3), c = 28.110(6) Å, β = 110.75(3)°, ρвыч = 2.232 г/см3, М = 2350.63, Z = 4, V = 6994(3) Å3

Short and long range order balance in nanocrystalline Gd2Zr2O7 powders with a fluorite pyrochlore structure

A series of nanocrystalline $Gd_{2}Zr_{2}O_{7}$ powders has been studied using a combination of X-ray diffraction and X-ray spectroscopy with synchrotron radiation. It has been shown that isothermal annealing of an X-ray amorphous mixed hydroxide first leads to the formation of an oxide nanomaterial with a defect fluorite structure and clearly pronounced nonequivalence of the local environment of the $Gd^{3+} and Zr^{4+}$ ions. Increasing heat treatment temperature results in initiation and growth of nanodomains with pyrochlore-type superstructure ordering of cations inside bulkier crystallites of defect fluorite. To adequately describe the evolution of the real nanocrystalline structure of gadolinium zirconate, a combination of X-ray structural methods sensitive to the averaged crystal structure and local atomic structure should be used

Effect of the synthesis conditions on the crystal, local, and electronic structure of Ce1-x 3+ Cex 4+ AlO3 + x/2

Cerium monoaluminate Ce1-x 3+ Cex 4+ AlO3+x/2 powders with low contents of Ce4+ cations (x ∼ 0.052) were synthesized. A set of modern local structure sensitive methods of analysis, including X-ray absorption spectroscopy and Raman spectroscopy, were used to study the crystal, local, and electronic structures of the synthesized compounds. The degree of reduction and the thermal stability to oxidation of reduced powders depend not only on the reduction conditions but also on the conditions of heat pretreatment of the initial samples. It was concluded that the reaction 4CeAlO3 + O2 ↔ 4CeO2 + 2Al2O3 is reversible. © Pleiades Publishing, Ltd., 2016