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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 242: 118723, 2020 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-32739517

RESUMO

The bulk interior of Kemer L4 ordinary chondrite was characterized for the first time by means of optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, Raman spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy with a high velocity resolution. The main and minor iron-bearing phases were found as well as ferrihydrite as a result of weathering. The Fe2+ partitioning among the M1 and M2 sites in olivine, orthopyroxene and clinopyroxene was determined from the X-ray diffraction. The ratios of Fe2+ occupancies for these crystals were estimated from both X-ray diffraction and Mössbauer spectroscopy data and appeared to be in a good agreement. The distribution coefficients KD and the temperatures of equilibrium cation distribution Teq were also evaluated for olivine and orthopyroxene from two independent techniques and were in a good consistence: KD = 1.77, Teq = 441 K (X-ray diffraction) and KD = 1.77, Teq = 439 K (Mössbauer spectroscopy) for olivine and KD = 0.10, Teq = 806 K (X-ray diffraction) and KD = 0.09, Teq = 787 K (Mössbauer spectroscopy) for orthopyroxene. The fusion crust of Kemer L4 was studied using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. Magnesioferrite and probably maghemite were found in the fusion crust in addition to other phases observed in the bulk interior.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 228: 117819, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31806480

RESUMO

The meteorite Sariçiçek, a 2015 howardite fall in Turkey, was analyzed using various physical techniques. Both the interior and the fusion crust were studied by optical and scanning electron microscopy with energy dispersive spectroscopy, X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. The main and minor iron-bearing phases such as orthopyroxene, Ca-poor and Ca-rich clinopyroxene, chromite with hercynite, Fe2+ and Fe3+ ilmenite, troilite, α-Fe(Ni, Co), α2-Fe(Ni, Co) and γ-Fe(Ni, Co) phases were identified. The ratios of Fe2+ occupancies in the M1 and M2 sites in the silicate phases as well as the equilibrium Fe2+ and Mg2+ cations distribution temperatures (Teq) for orthopyroxene were estimated using X-ray diffraction and Mössbauer spectroscopy, which appeared to be in a good agreement: for example, Teq were 886 and 878 K, respectively. The glass-like fusion crust of Sariçiçek consists of orthopyroxene with ferrous and ferric compounds that are likely products of combustion and melting.

3.
Dokl Biol Sci ; 486(1): 91-93, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31317453

RESUMO

Anodization of titanium implants is accompanied by the formation of titanium oxide nanotubes improving osseointegration. An excessive fibroblast adhesion on the surface might lead to the formation of fibrous capsule resulting in implant rejection. In our research, we demonstrated that the adhesion activity of human dermal fibroblasts on anodized surface was not elevated, which is promising for the use of titanium with nanotube-layered surface for implantology.


Assuntos
Materiais Biocompatíveis/farmacologia , Adesão Celular , Fibroblastos/fisiologia , Nanotubos/química , Titânio/farmacologia , Materiais Biocompatíveis/química , Interface Osso-Implante , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Humanos , Titânio/química
4.
Dokl Biol Sci ; 475(1): 175-179, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28861876

RESUMO

Methods for obtaining osteoblast cultures from the calvaria of adult Wistar rats and 12-day-old embryos of these rats have been adapted for studying the biocompatibility and ossointegration of titanium-based implants. The osteoblast morphology and their differentiation into osteocytes on a titanium matrix with specially treated surface have been studied. It has been confirmed that two cultures of diploid rat cells obtained in the study can serve as efficient models for preclinical in vitro testing of nanostructured titanium implants for biocompatibility and osseointegration.


Assuntos
Embrião de Mamíferos , Implantes Experimentais , Teste de Materiais , Osteoblastos , Titânio , Animais , Linhagem Celular , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Ratos
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