Ácido cítrico e quitosana na conservação de lichias 'Bengal'

The aim of this study was to evaluate citric acid application with or without chitosan on the maintenance of the quality of litchi 'Bengal'. It was used litchi on mature maturation stage. After selection, fruits were immersed for one minute on the solution of citric acid and chitosan: [1]Control - without immersion; [2] citric acid 300g L-1, [3] citric acid 300 g L-1 + chitosan 0,3%, [4]citric acid 300 g L-1 + chitosan 0,6%, [5] citric acid 600 g L-1, [6] citric acid 600 g L-1 + chitosan 0,3%, [7] citric acid 600 g L-1 + chitosan 0,6%. Chitosan of low molecular weight and deacetylation degree of 75,58% (Sigma - Aldrich®) were used. After immersion, fruits were put to drain the excess of solution. Then, they were stored in cool chamber at 5ºC, previously sanitized, for 20 days. The experiment was conducted following a completely randomized design, with a factorial scheme composed by seven coating solutions and five sampling dates. Every five days were evaluated: loss of fresh mass of fruits; color; content of anthocyanins and the activity of peel enzymes polyphenoloxidase and peroxidase. It was verified that the solution of citric acid 600 g L-1, associated or not to chitosan, and the combination of chitosan 0,3% to 300 g L-1 of citric acid were the most efficient to maintain the quality of litchi 'Bengal' for 20 days at 5ºC.

Abordagens biossintéticas em piper tuberculatum auxiliada pela síntese de precursores fenilpropanoídicos

Pós-graduação em Química - IQ

Effect of Resin Cement Type on the Microtensile Bond Strength to Lithium Disilicate Ceramic and Dentin Using Different Test Assemblies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of Surface Conditioning Modalities on the Repair Bond Strength of Resin Composite to the Zirconia Core / Veneering Ceramic Complex

Purpose: This study evaluated the effect of different surface conditioning protocols on the repair strength of resin composite to the zirconia core / veneering ceramic complex, simulating the clinical chipping phenomenon.Materials and Methods: Forty disk-shaped zirconia core (Lava Zirconia, 3M ESPE) (diameter: 3 mm) specimens were veneered circumferentially with a feldspathic veneering ceramic (VM7, Vita Zahnfabrik) (thickness: 2 mm) using a split metal mold. They were then embedded in autopolymerizing acrylic with the bonding surfaces exposed. Specimens were randomly assigned to one of the following surface conditioning protocols (n = 10 per group): group 1, veneer: 4% hydrofluoric acid (HF) (Porcelain Etch) + core: aluminum trioxide (50-mu m Al2O3) + core + veneer: silane (ESPE-Sil); group 2: core: Al2O3 (50 mu m) + veneer: HF + core + veneer: silane; group 3: veneer: HF + core: 30 mu m aluminum trioxide particles coated with silica (30 mu m SiO2) + core + veneer: silane; group 4: core: 30 mu m SiO2 + veneer: HF + core + veneer: silane. Core and veneer ceramic were conditioned individually but no attempt was made to avoid cross contamination of conditioning, simulating the clinical intraoral repair situation. Adhesive resin (VisioBond) was applied to both the core and the veneer ceramic, and resin composite (Quadrant Posterior) was bonded onto both substrates using polyethylene molds and photopolymerized. After thermocycling (6000 cycles, 5 degrees C-55 degrees C), the specimens were subjected to shear bond testing using a universal testing machine (1 mm/min). Failure modes were identified using an optical microscope, and scanning electron microscope images were obtained. Bond strength data (MPa) were analyzed statistically using the non-parametric Kruskal-Wallis test followed by the Wilcoxon rank-sum test and the Bonferroni Holm correction (alpha = 0.05).Results: Group 3 demonstrated significantly higher values (MPa) (8.6 +/- 2.7) than those of the other groups (3.2 +/- 3.1, 3.2 +/- 3, and 3.1 +/- 3.5 for groups 1, 2, and 4, respectively) (p < 0.001). All groups showed exclusively adhesive failure between the repair resin and the core zirconia. The incidence of cohesive failure in the ceramic was highest in group 3 (8 out of 10) compared to the other groups (0/10, 2/10, and 2/10, in groups 1, 2, and 4, respectively). SEM images showed that air abrasion on the zirconia core only also impinged on the veneering ceramic where the etching pattern was affected.Conclusion: Etching the veneer ceramic with HF gel and silica coating of the zirconia core followed by silanization of both substrates could be advised for the repair of the zirconia core / veneering ceramic complex.

ATP in the locus coeruleus as a modulator of cardiorespiratory control in unanaesthetized male rats

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

Estudo da infiltração marginal em restaurações de resinas compostas para dentes posteriores: efeito de material, preparo cavitário e condicionamento do esmalte a nível cervical

Pós-graduação em Odontologia Restauradora - ICT

Fabricação de filmes ultrafinos automontados para aplicações em células a combustível

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

On the stability of the RuCl2(triphenylphosphine)(2)(amine) complexes: Ligand substituent effects of cyclic and acyclic amines

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

Peptídeos cíclicos hepatotóxicos: MALDI-TOF como uma ferramenta analítica

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

Modulation of synaptic transmission in hippocampal CA1 neurons by a novel neurotoxin (beta-pompilidotoxin) derived from wasp venom

We examined the effects of beta-pompilidotoxin (beta-PMTX), a neurotoxin derived from wasp venom. on synaptic transmission in the mammalian central nervous system (CNS). Using hippocampal slice preparations of rodents, we made both extracellular and intracellular recordings from the CA1 pyramidal neurons in response to stimulation of the Schaffer collateral/commissural fibers. Application of 5-10 muM beta-PMTX enhanced excitatory postsynaptic potentials (EPSPs) but suppressed the fast component of the inhibitory postsynaptic potentials (IPSPs). In the presence of 10 muM bicuculline, beta-PMTX potentiated EPSPs that were composed of both non-NMDA and NMDA receptor-mediated potentials. Potentiation of EPSPs was originated by repetitive firings of the prosynaptic axons, causing Summation of EPSPs. In the presence of 10 muM CNQX and 50 muM APV, beta-PMTX suppressed GABA(A) receptor-mediated fast IPSPs but retained GABA(B) receptor-mediated slow IPSPs. Our results suggest that beta-PMTX facilitates excitatory synaptic transmission by a presynaptic mechanism and that it causes overexcitation followed by block of the activity of some population of interneurons which regulate the activity of GABA(A) receptors. (C) 2001 Published by Elsevier B.V. Ireland Ltd and the Japan Neuroscience Society.

Glyphosate effects on sugarcane metabolism and growth

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

Bioprospecção em espécies de Inga (Fabaceae Mimosoideae)

Pós-graduação em Química - IQ

Estudo químico dos escapos de Paepalanthus geniculatus Kunth

Eriocaulaceae species are popularly known as sempre-vivas. This family comprising approximately 1.200 species divided into 10 genera, with high endemic levels. Paepalanthus genus has high incidence in the Espinhaço Range region and the report of biological activities. Despite the large number of previous studies with Eriocaulaceae species, Paepalanthus geniculatus has no studies about their scapes, which demonstrates the need for new research to identify their chemical and biological composition. The aim of this work was to study the chemical composition of P. geniculatus ethanolic extract seeking the isolation and identification of metabolites and evaluate the radical scavenging activity of the extract and isolated substances. P. geniculatus were collected in Serra do Cipó-MG in 2013 (Voucher: SANO 3193) and the scapes were dried, crushed and the powder was percolated with ethanol. With the etanolic extract it is carried out a fractionation by gel permeation chromatography, yielding fractions analyzed by TLC assay. The fraction J89 (45,6 mg) was purified by semipreparative HPLC-PDA, resulting in the isolation of substance S1. The fractionation was also performed by medium pressure liquid chromatography, yielding fractions analyzed by TLC assay. The fraction number 4 (92,6 mg) were purified by semipreparative HPLC-PDA resulting in the isolation of substances S2 and S3. The substances S1 and S3 were analyzed by mono and twodimensional NMR, resulting in the identification of 3,4-dihydroxybenzoic acid (protocatechuic acid) and the flavonoid 6-hydroxyquercetin-7-O-β-Dglucopyranoside. The substance S2 were identified by comparison with standards, were it was possible to determine the presence of the flavonoid 6-hydroxy-7- methoxyquercetin-3-O-β-D-glucopyranoside. The evaluation of radical scavenging activity for the extract and the isolated substances using DPPH, showed consistent activity to S1...

Estudo químico dos escapos de Paepalanthus geniculatus Kunth

Eriocaulaceae species are popularly known as sempre-vivas. This family comprising approximately 1.200 species divided into 10 genera, with high endemic levels. Paepalanthus genus has high incidence in the Espinhaço Range region and the report of biological activities. Despite the large number of previous studies with Eriocaulaceae species, Paepalanthus geniculatus has no studies about their scapes, which demonstrates the need for new research to identify their chemical and biological composition. The aim of this work was to study the chemical composition of P. geniculatus ethanolic extract seeking the isolation and identification of metabolites and evaluate the radical scavenging activity of the extract and isolated substances. P. geniculatus were collected in Serra do Cipó-MG in 2013 (Voucher: SANO 3193) and the scapes were dried, crushed and the powder was percolated with ethanol. With the etanolic extract it is carried out a fractionation by gel permeation chromatography, yielding fractions analyzed by TLC assay. The fraction J89 (45,6 mg) was purified by semipreparative HPLC-PDA, resulting in the isolation of substance S1. The fractionation was also performed by medium pressure liquid chromatography, yielding fractions analyzed by TLC assay. The fraction number 4 (92,6 mg) were purified by semipreparative HPLC-PDA resulting in the isolation of substances S2 and S3. The substances S1 and S3 were analyzed by mono and twodimensional NMR, resulting in the identification of 3,4-dihydroxybenzoic acid (protocatechuic acid) and the flavonoid 6-hydroxyquercetin-7-O-β-Dglucopyranoside. The substance S2 were identified by comparison with standards, were it was possible to determine the presence of the flavonoid 6-hydroxy-7- methoxyquercetin-3-O-β-D-glucopyranoside. The evaluation of radical scavenging activity for the extract and the isolated substances using DPPH, showed consistent activity to S1...

Supercritical CO2 extraction of phenolic compounds from Baccharis dracunculifolia

Extracts from Baccharis dracunculifolia leaves were obtained using the following solvents: supercritical carbon dioxide (SC-CO2), ethanol and methanol. Supercritical extraction was carried out at temperatures of 40, 50 and 60 degrees C and pressures of 20, 30 and 40 MPa. Four phenolic compounds were analysed in the extracts by high-performance liquid chromatography: 3,5-diprenyl-4-hydroxycinnamic acid (DHCA or artepillin C); 3-prenyl-4-hydroxycinnamic acid (PHCA); 4-hydroxycinnamic acid (p-coumaric acid) and 4-methoxy-3,5,7-trihydroxyflavone (kaempferide). The global extraction yields (X-0) obtained by the conventional methods with ethanol and methanol were higher than those obtained by SC-CO2. However on analysing the components of interest extracted at 60 degrees C and 40 MPa, the extraction yields of kaempferide, DHCA and PHCA were 156%, 98% and 64% higher, respectively, than in the ethanolic extracts. Only the p-coumaric acid extraction yield was better when extracted using the conventional method. (C) 2008 Elsevier B.V. All rights reserved.