Monitoramento e avaliação da borracha natural crua utilizando a técnica de análise térmica dinâmico-mecânica

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

Avaliação de clones de borracha natural crua por ensaios padrão e análise dinâmico-mecânica

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

Thermomechanical characterization of PVDF and P(VDF-TrFE) blends containing corn starch and natural rubber

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

Tailoring the Structural Properties of PVDF and P(VDF-TrFE) by Using Natural Polymers as Additives

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

Caracterização de látices acrílicos em função da neutralização de seus grupos carboxilas

Latexes based on acrylic acid, acrylamide, ethyl methacrylate, and ethyl acrylate were synthesized via emulsion polymerization with different monomer compositions. The resultant latices were thickened with different molar ratios of NaOH to acrylic acid and were analyzed in terms of acid‐basis titrimetry, turbidimetry, rheology, and tensiometry. Titrimetry, turbidimetry, and rheometry were used to analyze factors such as carboxyl group availability and particle solubilization, tensiometry monitoring the influence of carboxyl neutralization on polymer‐surfactant interactions. For the acrylic acid content used in this work (20 wt%), the results indicated that as carboxyl groups distribution became more homogeneous, the process of latex thickening became more effective

Encapsulação de nanopartículas de magnetita em matriz de poli(metacrilato de metilacoácido metacrílico) por processo de polimerização em miniemulsão

Magnetic particles are systems with potential use in drug delivery systems, ferrofluids, and effluent treatment. In many situations, such as in biomedical applications, it is necessary to cover magnetic particles with an organic material, as polymers. In this work, magnetic particles were obtained through covering magnetite particles with poly(methyl methacrylate‐comethacrylic acid) via miniemulsion polymerization process. The resultant materials were characterized X‐ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential (��) measurements and vibrating sample magnetometry (VSM). XRD results showed magnetite as the predominant cristalline phase in all samples and that cristallites had nanometric dimensions. Thermogravimetric analysis revealed an increase in polymer thermal stability as a result of magnetite encapsulation. TGA results showed also that the encapsulation efficiency was directly related to nanoparticles s hidrofobicity degree. VSM measurements showed that magnetic polymeric particles were superparamagnetic, so that they may be potentially used for magnetic (bio)separation

Double aortic arch in a dog (Canis familiaris): a case report

We herein report a case of a double aortic arch in a 10-week-old male dog of no defined race, which presented episodes of regurgitation at the time of weaning. This vascular malformation was Characterized by the persistence of two aortic arches, right and left, of varying dimensions. The right aortic arch was observed to be larger. During post mortem examination the vessels of the animal were injected with coloured latex bi-centrifuged CIS 1-4 polisopreno which revealed the patency of the two aortic arches. Concomitantly, dilation of the cranial oesophagus causing constriction was observed, indicating megaesophagus, Apart from the constriction, the oesophagus presented normal morphometric parameters in relation to its dimensions.

Veias do sistema porta-hepático em gansos domésticos

A distribuição intraparenquimal das veias porta-hepáticas foi estudada em 30 gansos domésticos. Latex Neoprene corado foi injetado pela veia isquiática e os animais forma fixados por imersão e injeção intramuscular com formol a 10% e dissecados. O fígado esteve composto por um grande lobo hepático direito e por um lobo hepático esquerdo menor, os quais estiveram conectados por uma ponte de parênquima. O lobo direito do fígado teve exclusivamente vasos do sistema porta-hepático formados pela distribuição intraparenquimal da veia porta-hepática direita, enquanto que no lobo esquerdo estes originaram-se da veia porta-hepática direita e de pequenas veias porta-hepáticas esquerdas. A veia porta-hepática direita emitiu o ramo caudal direito, que emitiu um pequeno ramo caudolateral direito e um grande ramo caudomedial direito. Cranialmente esta veia emitiu os ramos craniais direito e ramos lateral direito. A porção transversa da veia porta-hepática direita cruzou para o lobo hepático esquerdo, emitindo de 1 a 6 pequenos ramos craniais e caudais para a região média do fígado. No lobo esquerdo, o ramo esquerdo da veia porta-hepática direita emitiu o ramo cranial esquerdo, o ramo lateral esquerdo e o ramo medial. de 1 a 6 veias porta-hepáticas esquerdas foram identificadas desembocando ou no ramo esquerdo da veia porta-hepática direita ou em sua porção transversa, oriundos do ventrículo gástrico e do pró-ventrículo. em 40% dos gansos uma veia porta-hepática própria oriunda da confluência de vasos venosos da face esquerda do ventrículo distribuiu-se na extremidade caudal do lobo esquerdo isoladamente.

Contribuição do contraste negativo na artrografia tomográfica do joelho normal de cães

A ruptura do ligamento cruzado cranial é uma das causas mais comuns de claudicação do membro pélvico de cães. A radiografia e a ultrassonografia são métodos de diagnóstico frequentemente utilizados na rotina clínica de pequenos animais, porém a tomografia computadorizada é uma modalidade de imagem ainda pouco estudada para avaliar a articulação do joelho de cães. O presente trabalho teve por objetivo avaliar a contribuição do contraste negativo na artrografia tomográfica do joelho normal de cães, para visibilizar as estruturas intra-articulares e padronizar o uso desse contraste na articulação. Foram utilizados 24 membros pélvicos de cães de raças variadas, selecionados pela ausência de histórico de doença articular prévia do joelho e por apresentarem exames radiográficos, ultrassonográficos e macroscópicos normais. O experimento foi delineado em dois grupos, sendo o grupo I constituído de animais com peso até 20 kg e grupo II acima de 20 kg. Foram feitos cortes tomográficos com o membro flexionado e estendido. A quantidade média de ar empregada para a distensão da cápsula articular foi de 49 ml para o Grupo I e de 81 ml para o Grupo II. Utilizou-se um tubo de látex na porção distal à articulação do joelho para reduzir o escape de ar pelo tendão extensor digital profundo, que possui comunicação intra-articular. Foi possível visibilizar pela imagem tomográfica, em todas as articulações, as seguintes estruturas: ligamento cruzado cranial e caudal, meniscos medial e lateral, ligamento patelar, ligamentos colaterais e cápsula articular. Desta forma, o contraste negativo se mostrou uma alternativa eficaz para auxiliar a identificação das estruturas anatômicas do joelho na artrografia tomográfica.

Accuracy of impression and pouring techniques for an implant-supported prosthesis

Purpose: The purpose of this in vitro study was to compare the dimensional accuracy of a stone index and of 3 impression techniques (tapered impression copings, squared impression copings, and squared impression copings splinted with acrylic resin) associated with 3 pouring techniques (conventional, pouring using latex tubes fitted onto analogs, and pouring after joining the analogs with acrylic resin) for implant-supported prostheses. Materials and Methods: A mandibular brass cast with 4 stainless steel implant-abutment analogs, a framework, and 2 aluminum custom trays were fabricated. Polyether impression material was used for all impressions. Ten groups were formed (a control group and 9 test groups formed by combining each pouring technique and impression technique). Five casts were made per group for a total of 50 casts and 200 gap values (1 gap value for each implant-abutment analog). Results: The mean gap value with the index technique was 27.07 mu m. With the conventional pouring technique, the mean gap values were 116.97 mu m for the tapered group, 5784 mu m for the squared group, and 73.17 mu m for the squared splinted group. With pouring using latex tubes, the mean gap values were 65.69 mu m for the tapered group, 38.03 mu m for the squared group, and 82.47 mu m for the squared splinted group. With pouring after joining the analogs with acrylic resin, the mean gap values were 141.12 jum for the tapered group, 74.19 mu m for the squared group, and 104.67 mu m for the squared splinted group. No significant difference was detected among Index, squarellatex techniques, and master cast (P > .05). Conclusions: The most accurate impression technique utilized squared copings. The most accurate pouring technique for making the impression with tapered or squared copings utilized latex tubes. The pouring did not influence the accuracy of the stone casts when using splinted squared impression copings. Either the index technique or the use of squared coping combined with the latex-tube pouring technique are preferred methods for making implant-supported fixed restorations with dimensional accuracy.

Persistence of endodontic methacrylate-based cement residues on dentin adhesive surface treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of methacrylate-based cement residues on the dentin, after dentin surface cleaning with ethanol or acetone, with or without previous application of a dentin adhesive. Forty bovine crown fragments were obtained and the dentin surface was washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% ethylenediaminetetraacetic acid application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. In 20 specimens, previously to cement, a dentin adhesive was applied in all surfaces. After 15 min, the surface was scrubbed with a cotton pellet and moistened with ethanol or acetone, compounding the following groups: G199.5% ethanol and G2acetone, without previous use of dentin adhesive; G399.5% ethanol and G4acetone, with previous use of dentin adhesive. The dentin surface was scrubbed until the cement residues could not be visually detected. Sections were then processed for scanning electron microscopy and evaluated at 500x magnification and scores were attributed to each image according to the area covered by residual sealer, and data were subjected to KruskalWallis at 5% significance. The lower residue presence was observed in G3 (P = 0.005). All surface presented cement residues when acetone was used as cleaning solution (P = 0.0005). The cleaning solutions were unable to completely remove the cement residues from both surfaces. The ethanol used after previous application of the dentin adhesive promoted the lower presence of residues.

Persistence of resinous cement residues in dentin treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of resin cement residues after dentin surface cleaning with different alcohol-based solutions or an essential oil (eucalyptol). Forty bovine teeth were sectioned in order to expose pulp chamber dentin to be washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% EDTA application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin-based cement was rubbed onto the dentine surface with a microbrush applicator. After 15 min, the surface was scrubbed with a cotton pellet and moistened with different dentin cleaning solutions, compounding the following groups: G195% ethanol, G270% ethanol, G370% isopropyl alcohol, or G4eucalyptol. The dentin was scrubbed until the cement residues could not be visually detected. Sections were then processed for SEM and evaluated at x 500 magnification. Scores were attributed to each image according to the area covered by residual sealer, and data were subjected to KruskalWallis at 5% significance. Eucalyptol promoted the most adequate dentin cleaning, although no statistical difference was detected amongst the groups (P > 0.05), except between the eucalyptol and 70% ethanol groups (P < 0.05). All the evaluated dentin cleaning solutions were unable to completely remove the cement residues from the dentin surface. Microsc. Res. Tech., 2012. (C) 2012 Wiley Periodicals, Inc.

Study on Cranial and Caudal Mesenteric Arteries in Opossum (Didelphis albiventris)

The objective of this study is to describe the cranial and caudal mesenteric arteries in 10 opossuns after Neoprene latex injection. The cranial mesenteric artery arises from the abdominal aorta, caudally to the celiac trunk, originating the caudal duodenal pancreatic artery, middle and right colic, jejunal and ileocecocolic arteries. The caudal mesenteric artery arises from the aorta, cranially to the external iliac arteries, originating the cranial rectal and left colic arteries.

Detection of enterotoxins genes in coagulase-negative staphylococci isolated from foods

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

Phenotype characterization of Staphylococcus species strains isolated from buffalo (Bubalus bubalis) milk

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