Cuidado com vacinas na perspectiva evolucionária de Rodgers

Medeiros, Suzane Gomes de; Santos, Viviane Euzébia Pereira

doi:10.5216/ree.v21.54309

Cited by 1 publication

(2 citation statements)

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“…The search for biomaterials that show bioactivity and bioreabsorption capacity led to the development of a material known as bioglass. The first formulation of this material was created by Larry L. Hench, in the 60s through Bioglass 45S5 with the composition 45% SiO 2 -24.5% Na 2 O-24.5% CaO-6% P 2 O 5 [1]. This material establishes a fast and durable chemical bond with bone tissue, through a surface of hydroxyapatite that is formed due to the release of ions between the implant and the body's physical solution [2].…”

Section: Introductionmentioning

confidence: 99%

“…An alternative method is a sol-gel technique, which has a low processing temperature and allows to obtain glasses with greater purity, homogeneity, and bioactivity [5][6][7]. This is because the sol-gel process allows greater chemical control of the surface and has fewer steps, reducing the risk of contaminations, in addition to generating products with higher surface area and porosity that are critical factors for its bioactivity [1,4]. In addition, it is a method that allows high reproducibility and can be easily adapted from laboratory production to a large scale [8].…”

Section: Introductionmentioning

confidence: 99%

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Influence of the use of rice husk as source of silica on the sol-gel synthesis of bioglass

2021

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Among the agro-industrial residues, the rice husk has stood out for presenting contents higher than 90% of silica, the main oxide of bioglass. Thus, the objective of this research was to compare the use of two different sources of silica, tetraethylorthosilicate (TEOS) and rice husk ash (RHA), in the sol-gel synthesis of the bioglass of the SiO 2 -CaO-Na 2 O system. For the silica extraction, the rice husk was treated with oxalic acid and calcined at 600 °C. This temperature was determined using thermogravimetry and the calcined powder was analyzed by X-ray diffraction and X-ray fluorescence spectroscopy, proving the achievement of highpurity amorphous silica. In the production of the bioglass, the solution made with the rice husk showed great synthesis efficiency, and the powder calcined was evaluated by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy. FTIR spectra presented characteristic bands of siloxane (Si-O-Si) bonds, which indicated a vitreous network and provided the formation of silanol groups, fundamentals for the growth of the hydroxyapatite layer. The microstructures of the samples were similar, but the sample made from RHA (BRHA) presented porous agglomerates, while the BTEOS had smaller and well-defined particles. The silica obtained from rice husk showed potential to be used in the sol-gel synthesis of bioglass.

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Section: Introductionmentioning

confidence: 99%