Evaluation of caries-associated virulence of biofilms from Candida albicans isolated from saliva of pediatric patients with sickle-cell anemia

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

Estudo da aplicabilidade do sistema pultrudado de fenólica/fibras de carbono em cabos condutores

Pós-graduação em Engenharia Mecânica - FEG

Estudo químico e atividade mutagênica e antirradicalar de caesalpinia ferrea

Pós-graduação em Química - IQ

Determination of carbofuran and diuron in FIA system using electrochemical sensor modified with organometallic complexes and graphene oxide

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

Suitability of carbon fiber-reinforced polymers as power cable cores: Galvanic corrosion and thermal stability evaluation

The increasing demand for electrical energy and the difficulties involved in installing new transmission lines presents a global challenge. Transmission line cables need to conduct more current, which creates the problem of excessive cable sag and limits the distance between towers. Therefore, it is necessary to develop new cables that have low thermal expansion coefficients, low densities, and high resistance to mechanical stress and corrosion. Continuous fiber-reinforced polymers are now widely used in many industries, including electrical utilities, and provide properties that are superior to those of traditional ACSR (aluminum conductor steel reinforced) cables. Although composite core cables show good performance in terms of corrosion, the contact of carbon fibers with aluminum promotes galvanic corrosion, which compromises mechanical performance. In this work, three different fiber coatings were tested (phenol formaldehyde resin, epoxy-based resin, and epoxy resin with polyester braiding), with measurements of the galvanic current. The use of epoxy resin combined with polyester braiding provided the best inhibition of galvanic corrosion. Investigation of thermal stability revealed that use of phenol formaldehyde resin resulted in a higher glass transition temperature. On the other hand, a post-cure process applied to epoxy-based resin enabled it to achieve glass transition temperatures of up to 200 degrees C. (C) 2014 Elsevier Ltd. All rights reserved.

Increasing Doxycycline Hyclate Photostability by Complexation with beta-Cyclodextrin

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização física e mecânica de compensado produzido com dois diferentes adesivos em duas variações de pressão de prensagem

The adhesives used in the production of engineered boards have been object of study over the years in order to improve the properties of the boards with less energy consumption, lower production costs and reduced environmental impact. In addition to that, process variables may affect the properties of the board. The present study aimed to characterize sheets of plywood, manufactured with two types of adhesives, under two different pressing conditions. The adhesives used for the study were Phenol-formaldehyde and Polyurethane castor oil based. The pressure of pressing was varied in a range from 75 to 160 Bar, in order to verify how they influence the physical and mechanical properties of the board. The tests performed resulted in a conclusion that shows that the moister content of the veneers interferes on the physical and mechanical tests. In general, boards produced with polyurethane resin showed superior physical and mechanical results; although the ones produced with phenol formaldehyde at a pressure of 75 Bar had always equal or higher values, compared to what is found in literature

Produção e caracterização físico-mecânica de painel de compensado de Eucalyptus sp. e adesivo PVA

Studies on new adhesives and resins for bonding wood and wood products are being conducted with the intention of improving their properties, taking into account a lower environmental impact. For this reason new formulations of polyvinyl acetate (PVA) adhesives have been developed, because they have no chemicals in its composition extremely polluting and harmful to health, as is the case of formaldehyde-based resins, which in turn are the most commonly used today for wood panels production. This study tested three different formulations of PVA adhesives, with different times and temperatures of pressing for the production of Eucalyptus sp. Plywood, coming up in satisfactory results with respect to shear strength at the bondline, which was higher for the PVA adhesives compared with urea-formaldehyde and phenol. The results of MOE and MOR were lower than those values of the panels produced with urea and phenol-formaldehyde, and the results of physical tests showed to be close to the panels produced with these same adhesives

Uma revisão sobre a resina uréia-formadeído (RUF) empregada na produção de painéis de madeira reconstituída

According to ABIPA (2009), Brazil is currently among the major producers of reconstituted wood panels, with one of the main factors for this condition, its climate and its large land area, which allows the cultivation of forests, which provide raw materials for these industries. To establish that market as power, Brazil has invested about R$ 1.3 billion in the last 10 years, yet designed an investment of 0.8 billion dollars over the next three years (BNDES, 2008). With the new investments in this segment, we expect a growth of about 66% in the resin consumption of urea-formaldehyde (GPC, 2009) which should also result in major investments by the companies producing this polymer. Currently employees are mainly three types of resins in the production industry panels, as follows: Urea-Formaldehyde Resin (R-UF), melamine-formaldehyde resin (R-MF) and Phenol-Formaldehyde Resin (R-FF). Especially the cost factor, the urea-formaldehyde resin is the most used by companies producing reconstituted wood panels. The UF-R is a polymer obtained by condensation of urea and formaldehyde reactors (usually batch type), characterized by being a thermosetting polymer which makes it very efficient for bonding wood composites. The urea-formaldehyde polymer, to present a quite complex, it becomes very difficult to predict the exact chain resulting in the process of condensation of urea with formaldehyde, so that a greater knowledge of its characteristics and methods for their characterization can result in greater control in industrial processes and subsequent decrease cost and improve the quality of reconstituted wood panels produced in Brazil

Sintese e caracterização da resina fenol-furfurílica para a obtenção de carbono vítreo monolítico

The monolithic glassy carbon is a carbonaceous material, isotropic, non graphitizable obtained by means of carbonization of resins up to 1000 °C. The good physicochemical properties make this material applied in several areas such as aerospace, medicine, electronics, chemistry, among others. It has generally been processed from the use of phenolic and furfuryl alcohol resins. These resins have high crosslink density and high fixed carbon content and are therefore widely applied in aerospace. The combination phenol / furfuryl alcohol resins search for obtaining the most suitable process for the glass-like carbon processing with phenolic resins currently available and of lower cost and easier to synthesize than the furfuryl alcohol resin. The main objective of this work is to obtain a phenol-furfuryl resin with high fixed carbon content combined with low porosity of the material. Different synthesis routes have been adopted along with thermal analysis techniques, FTIR and image analysis. The resin obtained through partial synthesis process presented the characteristics sought in this work

Caracterização morfológica e fenotípica de leveduras do gênero Cryptococcus com ênfase na pesquisa de Cryptococcus neoormans isoladas de amostras de água de mar e areia de três ambientes costeiros do estado de São Paulo: Canal de São Sebastião, Baixada Santista e Ubatuba

The yeast Cryptococcus neoformans is the etiologic agent of cryptococcosis, an infectious cosmopolitan disease that affects humans. Although rare, this disease is potentially fatal, especially for immunocompromised hosts. This pathogen is frequently isolated from excrements of pigeons and parrots, with many environmental sources such as birds, pigeon droppings, eucalyptus leaves, decaying trees, towers, churches and places of storage of grain (the port area). The isolation of this microorganism has been obtained also from the aquatic environment. The identification of environmental sources is needed to protect human health, especially susceptible populations such as immunocompromised. Therefore, this study investigated the presence of Cryptococcus neoformans in yeast isolates obtained from samples of sea water and sand from three regions of São Paulo: São Sebastião Channel, Santos and Ubatuba. Isolates were analyzed according to micro-and macroscopic characteristics and biochemical tests: microculture, urease, ink nankin, auxanograma, zymogram and phenol. We analyzed 199 isolates, 175 of which had features suggestive for Cryptococcus spp. in microculture. All these 175 isolates were sown in the Christensen urea middle to verify the production of urease and submitted to the technique nankin ink to visualize the capsule. Of these, only 24 were selected for the next test that was the auxanograma (assimilation of carbohydrate and nitrogen). Of the 24, 10 were tested in zymograms (fermented sugar), from which 5 were selected for the phenoloxidase test in medium containing dopamine. None of the 5 isolates tested had black or brown color characteristic of Cryptococcus neoformans. According to these tests, we arrived at 5 isolates identified to the genus Cryptococcus, but not the neoformans specie

Biosusceptometria de corrente alternada para avaliação do trânsito gastrintestinal de alimentos líquidos em ratos

The gastrointestinal tract is the main route of nutrients absorption and drugs delivery. Is important to know the parameters related to the tract, like gastric emptying and gastrointestinal transit, in order to better understand the behavior of different kind of meals or drugs passing through the GIT. Many techniques are used to study these parameters, such as manometry, scintigraphy, phenol red, activated charcoal and carbon-13 reading. However, these methods use radiation, are invasive and require animal sacrifice. As an alternative proposal, the Alternate Current Biosusceptometry (ACB), a magnetic technique, has proved to be effective for these studies with small animals, in a noninvasive way, low cost, radiation free and avoiding the animal death. Associating the ACB to magnetic micro or nanoparticles used as tracers, it is possible to observe the meal behavior inside of the GIT. Focusing meanly on liquid meals digestion, this paper had the objective to evaluate the efficiency of the ACB technique in gastric emptying and gastrointestinal transit evaluation of liquid meals in rats. To perform the experiments, magnetic nanoparticles (ferrite, MgFe2O4) were used on a 1,5 ml solution introduced by gavage on similar weight and age rats. The sensor made by 2 pairs of coils, capable of generating and detecting magnetic fields, creates a field on the interest place and when this field is in contact with the marked meal, it changes, resulting on a variation of the measured voltage. The voltage variation is analyzed and is obtained a particle concentration on the interest region. The results showed that is possible to apply the ACB technique on the GIT evaluation of liquid particles digestion, gastric emptying and meal cecum arrival time curves were obtained and from that, is possible to observe a pattern of gastrointestinal transit. Both mean process time values were acquired, proving the technique capability of ...

Avaliação dos efeitos citotóxicos, genotóxicos e mutagênicos do fipronil, após fotodegradação, utilizando Allium cepa como organismo teste

Compounds released into the environment can induce genetic alterations in living organisms. A group of chemicals that shows proven toxicity is the pesticides, and the insecticides are the most harmful. The insecticides of the family phenylpyrazole have wide application both in agriculture and in homes. Fipronil, an insecticide of this chemical group, is widely used in various cultures and in homes, mainly for fighting fleas and ticks on dogs and cats. The use of fipronil may represent a risk to man and the environmental health, since this pesticide can potentially induce cell death, regardless of cell type. Fipronil, when in contact with the environment, can undergo various degradation processes, including photodegradation. The toxic effect of one of its metabolites derived from photodegradation, sulfone-fipronil, is approximately 20 fold as great as fipronil itself. The A. cepa test system was used to evaluate cytotoxic, genotoxicity and mutagenic effects of fipronil before and after phptodegradation. Seeds of Allium cepa were subjected to solutions of fipronil, pre-exposed or not exposed to degradation by sunlight. The germination tests were conducted both under the effect of light and in the dark. We evaluated the cumulative potential of this insecticide using 48 and 72-hours recovery tests. The results showed that when fipronil was previously exposed to the sun, it presented a greater genotoxic and mutagenic potential, showing that the metabolites formed by photodegradation can show more harmfull effects

Sintese e caracterização do compósito TixOy- MWCNT para fotodegradação de carbaril

In this study, a composite of titanium oxide (TixOy) and carbon nanotubes multi-walled (MWCNT) was synthesized on a titanium substrate using the sol-gel method. The electrode obtained (TixOy-MWCNT/Ti) was used to the photodegradation of Carbaryl. The morphology and structure of the TixOy-MWCNT composite were characterized by scanning electron microscopy (SEM), scanning electron microscopy by field emission (FEG-SEM) and X-ray diffraction (XRD). The electrode was evaluated for degradation of Carbaryl (0.9 mmol L-1) in phosphate buffer pH 6, and using chronoamperometry by applying a potential of +1,5 V for 1 h. Using the Ultraviolet-Visible test, the absorbance at 220 nm was collected every 15 min to calculate the percentage of Cabaryl´s degradation. Can be evaluated that the Carbaryl degradation using the TixOy-MWCNT/Ti electrode was 22% more efficient when compared with the electrode without the presence of titanium oxides (MWCNT / Ti)

Obtenção e caracterização térmica de compósitos nanoestruturados de resina fenol-furfurílica/CNT

Pós-graduação em Engenharia Mecânica - FEG