Oligomers of poly(vinyl alcohol) were grafted onto poly(3-hydroxybutyrate) (PHB) by radiation-induced polymerization. The aim of this study was to elucidate the structure of these copolymers using nuclear magnetic resonance (heteronuclear multiple quantum coherence) spectroscopy supported by dynamic light scattering (DLS) and atomic force microscopy (AFM). It was concluded that vinyl alcohol (VA) was grafted onto PHB for the methylenic and methynic sites. A mechanism for the grafting reaction was proposed based on the experimental evidence. AFM and DLS allowed the characterization of the particles obtained from P(HB-g-VA). The prepared materials showed suitable properties for use in drug delivery systems.

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We have prepared carboxymethyl cellulose fibers (CMC) by chemically modifying cotton cellulose with monochloroacetic acid and calcium chloride solution. This modification favored the growth of hydroxyapatite (HAP) on the surface of the CMC fibers in contact with simulated body fluid solutions (SBF). After soaking in SBF for periods of 7, 14 and 21 days, formation of HAP was observed. Analysis by scanning electron microscopy and X-ray diffraction showed that crystallinity, crystallite size, and growth of HAP increased with the soaking time. The amount of HAP deposited on CMC fibers increased greatly after 21 days of immersion in the SBF, while the substrate surface was totally covered with hemispherical aggregates with the size of the order of 2 microns. Elemental analysis showed the presence of calcium and phosphate, with calcium/phosphate atomic ratio of 1.54. Fourier transform infrared spectroscopy bands confirmed the presence of HAP. The results suggest that cotton modified by calcium treatment has a nucleating ability and can accelerate the nucleation of HAP crystals.

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Review question / Objective: The aim of this systematic review is to determine whether mechanical vibration increases alveolar bone density in animals models and their possible application during orthodontic treatment. In this sense, the focused question is: Is the increase in alveolar bone density by mechanical vibrations in animal models an alternative to improve bone quality during orthodontic treatment? Eligibility criteria: All published animal studies will be included. Animal studies where high or low frequency vibrations were be applied, Articles where density or osteogenesis were be measured and compared to a control group. All publications will be considered except for those where the full-text article will not available, or the authors’ affiliation or the place of publication will not be specified. Only articles published in English.