Modified Synthesis and Physicochemical Characterization of a Bioglass-Based Composite for Guided Bone Regeneration.

OBJECTIVES: Bioglass composites and polymers are materials of great interest for the medical and dental areas due to their properties, combining the bioactivity of ceramic materials and the mechanical properties of polymers. The purpose of the present study was to develop and to characterize the physicochemical and morphological properties an experimental bioglass-based ternary composite composed associated with sodium carboxymethylcellulose (Na-CMC) and polyvinyl alcohol (PVA). The compatibility of functional groups with bioglass was previously evaluated. The composite was then synthesized and evaluated in terms of morphology, elemental composition, compressive strength, porosity, and bioactivity. MATERIALS AND METHODS: The bioglass was previously synthesized using a sol-gel route and characterized using FTIR analysis to identify the functional groups. The bone graft composite was then synthesized associating the bioglass with PVA, surfactant Triton X, and Na-CMC. The composite was then morphologically characterized using SEM/EDS. The porosity of the composite was analyzed using µCT, which also provided the composite compression strength. The composite was then evaluated in terms of its bioactivity using SEM/EDS analyses after immersion in SBF for 12, 24, 48, and 72 h. RESULTS: FTIR analysis confirmed, among other components, the presence of Si-O-Ca and Si-O-Si bonds, compatible with bioglass. SEM analysis exhibited a composite with a porous structure without spikes. The elemental mapping confirmed the presence of Si, Ca, and P in the composite. µCT analysis demonstrated a porous structure with 42.67% of open pores and an average compression strength of 124.7 MPa. It has also demonstrated ionic changes in the composite surface after immersion in SBF, with increasing detection of Ca and P as a function of time, highlighting its chemical bioactivity. CONCLUSIONS: It can be concluded that the proposed bioglass-based composite presents a three-dimensional, well-structured, chemically bioactive porous structure, mechanically resistant for being reinforced with polymeric phases, with promising results as a synthetic bone graft, which makes it suitable for guided bone regeneration.

DNA Barcoding for the Identification of Phyllanthus Taxa Used Medicinally in Brazil.

Plants of the genus Phyllanthus, principally Phyllanthus amarus, Phyllanthus urinaria, Phyllanthus niruri, and Phyllanthus tenellus, are used in Brazilian folk medicine to treat kidney stones as well as other ailments, where the latter two species are listed in the Brazilian Pharmacopeia as quebra-pedra (stone-breaker). However, only P. niruri has been shown to be effective in a clinical setting. Nuclear ribosomal internal transcribed spacer (ITS1 - 5.8S rRNA-ITS2), internal transcribed spacer 2, and chloroplasts rbcL, matK, psbA-trnH, trnL, and trnL-trnF were screened for their potential as DNA barcodes for the identification of 48 Phyllanthus taxa in Brazilian medicinal plant germplasm banks and in "living pharmacies". The markers were also tested for their ability to validate four commercial herbal teas labelled as quebra-pedra. Using the criterion of high clade posterior probability in Bayesian phylogenetic analysis, the internal transcribed spacer, internal transcribed spacer 2, and chloroplast matK, psbA-trnH, trnL, and trnL-trnF markers all reliably differentiated the four Phyllanthus species, with the internal transcribed spacer and matK possessing the additional advantage that the genus is well represented for these markers in the Genbank database. However, in the case of rbcL, posterior probability for some clades was low and while P. amarus and P. tenellus formed monophyletic groups, P. niruri and P. urinaria accessions could not be reliably distinguished with this marker. Packaged dried quebra-pedra herb from three Brazilian commercial suppliers comprised P. tenellus, but one sample was also found to be mixed with alfalfa (Medicago sativa). An herb marketed as quebra-pedra from a fourth supplier was found to be composed of a mixture of Desmodium barbatum and P. niruri.

Correction to: Extrafloral nectaries of four varieties of Chamaecrista ramosa (Vogel) H.S.Irwin & Barneby (Fabaceae): anatomy, chemical nature, mechanisms of nectar secretion, and elimination.

The published online version contains mistake. The author name Letícia de Almeida Golçalves should be Letícia de Almeida Gonçalves. Corrected name is shown in the author group section above.

Extrafloral nectaries of four varieties of Chamaecrista ramosa (Vogel) H.S.Irwin & Barneby (Fabaceae): anatomy, chemical nature, mechanisms of nectar secretion, and elimination.

Considering the importance of extrafloral nectaries (EFNs) in Fabaceae, the objectives of this research were to analyze (1) the anatomical and histochemical characteristics of the EFNs of Chamaecrista ramosa var. ramosa, C. ramosa var. curvifoliola, C. ramosa var. parvifoliola, and C. ramosa var. lucida and (2) the ultrastructure of the EFNs of C. ramosa var. ramosa. Standard techniques in plant anatomy and transmission electron microscopy were used. The anatomical analyses confirmed the characteristics described for extrafloral nectaries, evidencing three well-defined regions: epidermis, nectariferous, and subnectariferous parenchymas. Carbohydrates, proteins, pectins/mucilages, and lipids were detected by histochemical analyzes in all varieties. The ultrastructure of the EFNs of C. ramosa var. ramosa allowed the observation of microchannels at the external periclinal cell walls of the epidermis covering the secretory region. The nectariferous and subnectariferous parenchyma cells have periplasmic spaces, large plastids containing starch grains and plastoglobules, mitochondria, developed endoplasmic reticulum, large vacuoles with electron-dense contents, and membrane residues may be associated with the vacuole, suggesting the occurrence of autophagic processes. The anatomical, histochemical, and ultrastructural patterns revealed characteristics that confirm the glands of C. ramosa as extrafloral nectaries and suggest the eccrine mechanism of secretion.

Morphological characteristics and genetic evidence reveals a new species of Manihot (Euphorbiaceae, Crotonoideae) from Goiás, Brazil.

During botanical expeditions between 2010 and 2015, as part of a taxonomic study of Manihot in the Midwest region of Brazil, approximately 500 specimens of the genus were collected. Some of these specimens presented similarities to Manihot irwinii. However, after careful morphological analyses, associated with genetic evidence, we propose here Manihot pulchrifolius as a new species. The new species is described, illustrated, and compared to Manihot irwinii, its most similar species. Furthermore, geographic distribution, conservation status, and period of flowering and fruiting of the novel species are also provided.

Morphological and anatomical evidence support a new wild cassava: Manihot fallax (Crotonoideae, Euphorbiaceae), from Mato Grosso, Brazil.

During the preparation of the taxonomic treatment of Manihot in the Midwest Region of Brazil, a new species was found. Manihot fallax M.J. Silva & L.S. Inocencio is described, illustrated and morphologically compared with similar simple-leaved species. The conservation status, geographic distribution (including map), ecology, phenology and notes about leaf anatomy of the new species are given. The synonymisation of M. robusta M. Mend. & T. B. Cavalc. under M. attenuata Müll. Arg. and lectotypes for M. attenuata and M. brachystachys Pax & K. Hoffm are also proposed. An emended description of M. attenuata is proposed as the original description is incomplete as it lacks information on the pistillate flowers, fruits and seeds.