Effect of UV-photofunctionalization on oral bacterial attachment and biofilm formation to titanium implant material

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Saresp e diversidade textual: perspectivas na formação do leitor

Pós-graduação em Educação - FCT

Branch formation in Pulvinularia suecica (Nostocales, Cyanoprokaryota) and considerations on the classification of dichotomously and pseudodichotomously branched genera

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of processing route on the phase formation and properties of Bi4Ti3O12 ceramics

Our efforts were directed to the preparation of bismuth titanate-Bi4Ti3O12 (BIT) by two procedures: mechanically assisted synthesis and polymeric precursor method to display a variety of their advantages. To follow the nucleation and phase formation of BIT, XRD and Rietveld refinement analysis were used and it was shown that Bi4Ti3O12 ceramic can been successfully prepared from nano-sized powders obtained by both methods. The ferroelectric properties were determined and the loops from BIT obtained by polymeric precursor method were not fully saturated with a remnant polarization of 20 mu C/cm(2) and coercitive field of 1500 kV/cm. BIT obtained from powders prepared by mechanically assisted synthesis shows a remnant polarization of 0.65 mu C/cm(2) and coercitive field of 1050 kV/cm. The grain morphology may be the factor causing the observed differences. (C) 2005 Published by Elsevier Ltd and Techna Group S.r.l.

SAXS study of formation and growth of tin oxide nanoparticles in the presence of complexing ligands

The effect of acetylacetone (acac) complexing ligand on the formation and growth of tin oxide-based nanoparticles during thermohydrolysis at 70 degreesC of a tin precursor SnCl4-n(acac)(n) (0 less than or equal to n less than or equal to 2) solution was analyzed by in situ small-angle X-ray scattering. A. transparent and stable sol was obtained after 2 h of thermohydrolysis at 70 degreesC, allowing the quantitative determination of the particle volume distribution function and its variation with the reaction time. The number of colloidal particles for equivalent thermohydrolysis temperature and time decreases as the [acac]/[Sn] ratio in initial solution increases from 0.5 to 6. Instead, the amount of soluble species remaining in solution increases for increasing [acac]/[Sn] ratio within the same range. This indicates that increasing amounts of Sn-acetylacetone complexes partially prevent the hydrolysis and consequent formation of colloidal particles. The N-2 adsorption isotherm characterization of freeze-dried powders demonstrates that the average pore size is approximately equal to the average size (approximate to9 Angstrom) of the colloidal primary particles in the sol, and that the porosity and surface area (approximate to200 m(2) g(-1)) are independent of the acac content in the initial solution.

Subinhibitory Concentrations of Triclosan Promote Streptococcus mutans Biofilm Formation and Adherence to Oral Epithelial Cells

Triclosan is a general membrane-active agent with a broad-spectrum antimicrobial activity that is commonly used in oral care products. In this study, we investigated the effect of sub-minimum inhibitory concentrations (MICs) of triclosan on the capacity of the cariogenic bacterium Streptococcus mutans to form biofilm and adhere to oral epithelial cells. As quantified by crystal violet staining, biofilm formation by two reference strains of S. mutans was dose-dependently promoted, in the range of 2.2- to 6.2-fold, by 1/2 and 1/4 MIC of triclosan. Observations by scanning electron microscopy revealed the presence of a dense biofilm attached to the polystyrene surface. Growth of S. mutans in the presence of triclosan at subMICs also increased its capacity to adhere to a monolayer of gingival epithelial cells. The expression of several genes involved in adherence and biofilm formation in S. mutans was investigated by quantitative RT-PCR. It was found that subMICs of triclosan significantly increased the expression of comD, gtfC, and luxS, and to a lesser extent of gtfB and atlA genes. These findings stress the importance of maintaining effective bactericidal concentrations of therapeutic triclosan since subMICs may promote colonization of the oral cavity by S. mutans.

The symbology of the sea in Lygia Bojunga Nunes's work: a reflection on utopian and dystopian framing

The ambivalent image of the sea is recurrent in Bojunga Nunes’s work. It receives a lot of symbolic meanings in her production, being sometimes a positive and sometimes a negative element. Thus, the sea is used in a utopic way, as a place for pleasure and leisure, and in a dystopic way, as scenery of a rite of passage, which includes the pain and suffering, part of the rite of passage that characterizes the bildungsromans. So, if in some texts the sea assumes a utopic character, being a place of snuggle, security, the ideal to reach, in others it is represented as dystopic, a place of distress, asphyxia and death. In this text we will study the hypothesis that, even in its dark symbolic meaning, in the author’s work the sea is an element of reflection and revelation. Thereby, it assumes metaphorically a sense of magnification of the reader’s expectative, being an element of emancipation. The objective of this text is to present a reflection on the sea’s symbolism on the mentioned texts and its importance for the reader’s formation.

Rimbaud, Molière e Sade lidos pelos brasileiros: aspectos da representação literária dos escritores franceses homenageados na coleção Literatura ou Morte

Pós-graduação em Letras - FCLAS

Demecolcine Effects on Microtubule Kinetics and on Chemically Assisted Enucleation of Bovine Oocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oxidation of melatonin and its catabolites, N-1-acetyl-N (2)-formyl-5-methoxykynuramine and N-1-acetyl-5-methoxykynuramine, by activated leukocytes

N-1-acetyl-N-2-formyl-5-methoxykynuramine (AFMK) and N-1-acetyl-5-methoxykynuramine (AMK), two melatonin catabolites, have been described as potent antioxidants. We aimed to follow the kinetics of AFMK and AMK formation when melatonin is oxidized by phorbol myristate acetate (PMA) and lipopolysaccharide (LPS)-activated leukocytes. An HPLC-based method was used for AFMK and AMK determination in neutrophil and peripheral blood mononuclear cell cultures supernatants. Samples were separated isocratically on a C18 reverse-phase column using acetonitrile/H2O (25:75) as the mobile phase. AFMK was detected by fluorescence (excitation 340 nm and emission 460 nm) and AMK by UV-VIS absorbance (254 nm). Activation of neutrophils and mononuclear cells with PMA produces larger amounts of AFMK than activation with LPS, probably due to the lower levels of reactive oxygen species formation and myeloperoxidase (MPO) degranulation that occurs when cells are stimulated with LPS. The concentration of AMK found in the supernatant was about 5-10% (from 18-hr cultures) compared with AFMK. This result may reflect its reactivity. Indeed AMK, but not AFMK, is easily oxidized by activated neutrophils in a MPO and hydrogen peroxide-dependent reaction. In conclusion, we defined a simple procedure for the determination of AFMK and AMK in biological samples and demonstrated the capacity of leukocytes to oxidize melatonin and AMK.

Propolis as storage media for avulsed teeth: microscopic and morphometric analysis in rats

The maintenance of the avulsed teeth in appropriate media for preserving the cellular viability has been important for repairing the periodontal ligament and preventing the root resorption after tooth reimplantation. Propolis is a substance capable of preserving cellular viability. This study aimed to analyze the propolis substance as a storage media for maintaining the avulsed teeth, besides to determine the ideal time period for keeping the tooth inside it. Thus, 60 maxillary right central incisors of rats were extracted and divided into five groups. In groups I and II, teeth were kept in propolis for 60 min and 6 h, respectively; in group III, teeth were kept in milk for 6 h; in group IV, teeth were kept dry for 60 min; and in group V, they were immediately reimplanted. All teeth had their root canals filled with calcium hydroxide paste. Following, teeth were reimplanted in their sockets. After 15 and 60 days, animals were killed and the obtained samples were processed in laboratory for microscopic and morphometric analyzing. The results showed that the occurrence of inflammatory resorption, dental ankylosis and the formation of the connective tissue parallel to the root surface were similar among groups. It could be verified a greater occurrence of replacement resorption in group IV when comparing to other groups. In groups I and IV, the presence of periodontal ligament-like connective tissue was substantially smaller than the other groups. Regarding to the cementum amount over the root, it could be observed that this was present in smaller amount in groups I and IV. Group II was similar to groups III and IV. Therefore, according to the results of this study, the use of propolis as a storage media for maintaining avulsed teeth could be highlighted, and the 6-h period was more appropriate than the 60-min period.

Anatomy and ontogeny of the pericarp of Pterodon emarginatus Vogel (Fabaceae, Faboideae), with emphasis on secretory ducts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seasonal development of secondary xylem and phloem in Schizolobium parahyba (Vell.) Blake (Leguminosae : Caesalpinioideae)

The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. This paper describes the relationship between seasonal cambial activity, xylem and phloem development, and phenology in Schizolobium parahyba, a fast growing semideciduous seasonal forest tree from southeastern Brazil. From 2002 to 2003, wood samples were collected periodically and phenology and climate were recorded monthly in the same period. S. parahyba forms annual growth increments in wood, delimited by narrow initial parenchyma bands. The reduction of the cambial activity to a minimum correlates to the dry season and leaf fall. The higher cambial activity correlates to the wet season and the presence of mature leaves. In phloem, a larger conductive region was observed in the wet season, when the trees were in full foliage. The secondary phloem did not exhibit any incremental zone marker; however, we found that the axial parenchyma tends to form irregular bands.

In situ evaluation of anticancer drug methotrexate-DNA interaction using a DNA-electrochemical biosensor and AFM characterization

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Developmental anatomy and morphology of the ovule and seed of Heliconia (Heliconiaceae, Zingiberales)

The developmental anatomy and morphology of the ovule and seed in several species of Heliconia were investigated as part of an embryological study of the Heliconiaceae and to provide a better understanding of their relationships with the other families of the Zingiberales. Heliconia species have an ovule primordium with an outer integument of both dermal and subdermal origin. The archesporial cell is divided into a megasporocyte and a single parietal cell, which in turn are divided only anticlinally to form a single parietal layer, disintegrating later during gametogenesis. The embryo sac was fully developed prior to anthesis. In the developing seed, the endosperm was nuclear, with wall formation in the globular stage; a nucellar pad was observed during embryo development, but later became compressed. The ripe fruit contained seeds enveloped by a lignified endocarp that formed the pyrenes, with each pyrene having an operculum at the basal end; the embryo was considered to be differentiated. Most of these characteristics are shared with other Zingiberales, although the derivation of the operculum from the funicle and the formation of the main mechanical layer by the endocarp are unique to the Heliconiaceae.