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991.
Alexandre Félix FragaEdson de Almeida Filho Eliana Cristina da Silva RigoAnselmo Ortega Boschi 《Applied Surface Science》2011,257(9):3888-3892
Chitosan, which is a non-toxic, biodegradable and biocompatible biopolymer, has been widely researched for several applications in the field of biomaterials. Calcium phosphate ceramics stand out among the so-called bioceramics for their absence of local or systemic toxicity, their non-response to foreign bodies or inflammations, and their apparent ability to bond to the host tissue. Hydroxyapatite (HA) is one of the most important bioceramics because it is the main component of the mineral phase of bone. The aim of this work was to produce chitosan membranes coated with hydroxyapatite using the modified biomimetic method. Membranes were synthesized from a solution containing 2% of chitosan in acetic acid (weight/volume) via the solvent evaporation method. Specimens were immersed in a sodium silicate solution and then in a 1.5 SBF (simulated body fluid) solution. The crystallinity of the HA formed over the membranes was correlated to the use of the nucleation agent (the sodium silicate solution itself). Coated membranes were characterized by means of scanning electron microscopy - SEM, X-ray diffraction - XRD, and Fourier transform infrared spectroscopy - FTIR. The results indicate a homogeneous coating covering the entire surface of the membrane and the production of a semi-crystalline hydroxyapatite layer similar to the mineral phase of human bone. 相似文献
992.
Dr. Simone Ghinato Federica De Nardi Paola Bolzoni Dr. Achille Antenucci Dr. Marco Blangetti Prof. Cristina Prandi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(37):e202201154
A straightforward and efficient protocol to promote the metalation/anionic Fries rearrangements of O-aryl carbamates, using for the first time a lithium amide as metalating agent under aerobic/ambient-friendly reaction conditions, is reported. This approach enables the sustainable preparation of salicylamide derivatives with high levels of chemoselectivity within ultrafast reaction times, working at room temperature in the presence of air/moisture, and using environmentally responsible cyclopentyl methyl ether as a solvent. Furthermore, the regioselective manipulation of O-2-tolyl carbamates has been accomplished using interchangeably alkyllithiums or lithium amides, with an unexpected beneficial contribution from the employment of biorenewable protic eutectic mixtures as non-innocent reaction media. 相似文献
993.
Fast and reliable determination of antioxidant capacity based on the formation of gold nanoparticles
Vilela Diana Castañeda Raquel González María Cristina Mendoza Sandra Escarpa Alberto 《Mikrochimica acta》2015,182(1-2):105-111
Microchimica Acta - We demonstrate that the formation of gold nanoparticles (AuNPs) can be exploited in a well-defined and reliable electron-transfer assay for antioxidant capacity (AOxC). The AOxC... 相似文献
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