Publications by authors named "J Vieira"

1,251 Publications

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Magnetic-field-assisted deposition of self-assembling crystallite layers of Co-containing layered double hydroxides.

Chem Commun (Camb) 2021 Jun 21. Epub 2021 Jun 21.

Department of Materials and Ceramic Engineering, CICECO - Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.

Precipitation of nanocrystallites of cobalt-aluminium layered double hydroxides in a magnetic field has been studied. In a magnetic field perpendicular to the substrate, dense and homogeneous films have been obtained. Magnetic anisotropy of the crystallites is explained by deviation from the statistical cation distribution in favour of honeycomb-like coordination of cobalt.
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http://dx.doi.org/10.1039/d1cc01599kDOI Listing
June 2021

Dissolution, bioactivity behavior, and cytotoxicity of 19.58Li O·11.10ZrO ·69.32SiO glass-ceramic.

J Biomed Mater Res B Appl Biomater 2021 Jun 14. Epub 2021 Jun 14.

Engenharia Química, Universidade do Extremo Sul Catarinense, Criciúma, Brazil.

Glass and bioactive glass-ceramic can be used in several applications. In bone growth where good bone/biomaterial adhesion was required, bioactive coatings for implants can improve bone formation. The glass and glass-ceramics of the LZS (Li O-ZrO -SiO ) system are very interesting because of their mechanical, electrical, and thermal properties. Very recently, their biological response in contact with human osteoblast has been evaluated. However, despite several initiatives, there are still no studies that systematically assess this system's bioactivity, dissolution, and cytotoxicity in vitro. This work aims to investigate the dissolution, bioactivity behavior, and cytotoxicity of LZS glass-ceramic. LZS glass-ceramics were produced from SiO , Li CO and ZrSiO by melting followed by quenching. The obtained glass frits were milled and uniaxially pressed and heat-treated at 800 and 900°C and submitted to physical-chemical, structural and mechanical characterization. Their dissolution behavior was studied in Tris-HCl, while bioactivity was performed in simulated solution body fluid (SBF). The cytotoxicity test was performed using glass-ceramic in direct contact with mesenchymal stem/stromal cells (SC) isolated from human exfoliated deciduous teeth. Structural and microstructural analyzes confirmed bioactivity. The results show that it was possible to produce bioactive glass-ceramic from LZS, proven by the formation of new calcium phosphate structures such as hydroxyapatite on the surface of the samples after exposure to SBF. The SC viability test performed indicated that the materials were not cytotoxic at 0.25, 0.5, and 1.0 mg/ml. The glass-ceramic system under study is very promising for a medicinal application that requires bioactivity and/or biocompatibility for bone regeneration.
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http://dx.doi.org/10.1002/jbm.b.34889DOI Listing
June 2021

Cyperus prophyllatus: An endangered aquatic new species of Cyperus L. (Cyperaceae) with a exceptional spikelet disarticulation pattern among about 950 species, including molecular phylogenetic, anatomical and (micro)morphological data.

PLoS One 2021 9;16(6):e0249737. Epub 2021 Jun 9.

Departamento de Botânica, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.

Cyperus prophyllatus, an endangered new species of Cyperus (Cyperaceae) from an aquatic ecosystem of the Atlantic Forest, Espírito Santo State, southeastern Brazil, is described and illustrated. The spikelet morphology of Cyperus prophyllatus is unique among the c. 950 species of Cyperus in having both a conspicuous spikelet prophyll and a corky rachilla articulation, which remain persistent at the base of the spikelet after disarticulation. Our molecular phylogenetic data support the placement of C. prophyllatus in the C3 Cyperus Grade and more precisely in the clade representing Cyperus sect. Oxycaryum, which also includes C. blepharoleptos and C. gardneri. Anatomical and (micro)morphological analyses corroborate the phylogenetic results, provide a better understanding of ecology and taxonomy, as well as reveal compatibility of structures with survival and dispersion in aquatic environments. A distribution map, table with distinctive characters of allied species, and conservation status are made available.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249737PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8189457PMC
June 2021