Habitat Split as a Cause of Local Population Declines of Amphibians with Aquatic Larvae

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

Influência da temperatura e da concentração do cloreto de sódio (NaCl) nas isotermas de sorção da carne de tambaqui (Colossoma macroparum)

As isotermas de sorção da carne de tambaqui desidratada osmoticamente foram determinadas a três temperaturas (5, 17 e 29ºC) e com duas concentrações de solução osmótica (10 e 30% de NaCl), pelo método gravimétrico. Quatro modelos de sorção foram testados para verificar o melhor ajuste; GAB, Oswin, BET e PELEG. Os dados experimentais se ajustaram satisfatoriamente aos modelos. O modelo escolhido para este trabalho foi o de PELEG. Para o ajuste nas curvas de sorção, foi feita a análise de regressão não-linear, usada o programa estatístico ORIGIN 4.0 para estimar as constantes dos modelos. A avaliação do melhor ajuste foi feita pela análise do coeficiente de determinação do ajuste (r²) e teste de Qui-quadrado (x²). Foram analisadas as influências da variação da temperatura e concentração de NaCl na atividade de água da carne do tambaqui. À medida que decresce a temperatura há um decréscimo na atividade de água. Um aumento na concentração do NaCl diminui a atividade de água. A propriedade termodinâmica estudada foi o calor isostérico de sorção. A medida que aumenta a concentração da solução osmótica aumenta o valor do calor isostérico de sorção.

Ascorbic acid degradation kinetics in tomatoes at different drying conditions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Utilização de métodos combinados para obtenção de mamão formosa (carica papaya) seco

COMBINED METHODS TO OBTAIN DRIED PAPAYA of FORMOSA CULTIVAR (Carica papaya) The aim of this work was to evaluate the influence of blanching in hot water, osmotic dehydration in sucrose solution and pectin coating on color and water activity of papaya slices after convective drying. on the first experiments, the influence of concentration and time of dehydration on color changes and water activity of fresh and blanched papaya slices was evaluated based on a factorial design. It was not verified significant color changes at the studied ranges. An expression for the water activity of osmotically dehydrated blanched samples was found. Then, the influences of blanching, osmotic dehydration, edible coating and combinations among these pre-treatments on color and water activity were evaluated after convective drying of papaya slices. Blanching was not an advantageous pre-treatment to maintain color and reduce water activity of dried fruits. Osmotically dehydrated fresh samples with or without coating presented the best results.

Influência de pré-influência de pré-tratamentos sobre a desidratação osmótica de carambolas

A desidratação osmótica (DO) de fatias de carambola (Averrhoa carambola L.) em solução de sacarose foi estudada, com o objetivo de otimizar o processo. Num primeiro conjunto de experimentos, aplicou-se revestimento de coberturas comestíveis (pectina ou pectina+amido) sobre as fatias, seguido de do em solução aquosa de sacarose (50%, p/p, 27°C). Num segundo conjunto, foi realizada secagem parcial da cobertura, em estufa, antes da DO. Num terceiro conjunto de experimentos testou-se a adição de CaCl2 na solução osmótica. A aplicação dos revestimentos antes da do não melhorou a eficiência (máxima perda água/ganho soluto) devido à grande retenção de umidade e à fácil impregnação de sacarose nos mesmos, enquanto que o tecido vegetal sem revestimento restringiu mais o ganho de soluto e propiciou maior saída de água. A utilização de CaCl2 a 0,04M, na própria solução osmótica de sacarose, melhorou ligeiramente a eficiência do processo, em relação à solução sem o sal. A do em solução de sacarose, sem e com a adição de CaCl2, geraram resultados positivos na qualidade sensorial da carambola em fatias, desidratadas em secador (60 e 70°C), em comparação com a fruta não tratada, sendo que a melhor temperatura de secagem foi 60°C.

Efeito do pré-tratamento osmótico com sacarose e cloreto de sódio sobre a secagem convectiva de abóbora

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

An ultraviolet photoacoustic spectroscopy study of the interaction between Lys49-phospholipase A(2) and amphiphilic molecules

We have used near ultraviolet photoacoustic spectroscopy (PAS) over the wavelength range 240-320 nm to investigate the complex formed between the homodimeric bothropstoxin-I, a lysine-49-phospholipase A(2) from the venom of Bothrops jararacussu (BthTx-I), with the anionic amphiphile sodium dodecyl sulfate (SDS). At molar ratios > 10, the complex developed a significant light scatter, accompanied by a decrease in the intrinsic tryptophan fluorescence intensity emission (ITFE) of the protein, and an increase in the near UV-PAS signal. Difference PAS spectroscopy at SDS/BthTx-I ratios < 8 were limited to the region 280-290 nm, suggesting initial SDS binding to the tryptophan 77 located at the dimer interface. At SDS/BthTx-I ratios > 10, the intensity between 260 and 320 nm increases demonstrating that the more widespread tyrosine and phenylalanine residues contribute to the SDS/BthTx-I interaction. PAS signal phase changes at wavelengths specific for each aromatic residue suggest that the Trp77 becomes more buried on SDS binding, and that protein structural changes and dehydration may alter the microenvironments of Tyr and Phe residues. These results demonstrate the potential of near UV-PAS for the investigation of membrane proteins/detergent complexes in which light scatter is significant. (c) 2006 Elsevier B.V. All rights reserved.

Synthesis, characterization and solution properties of amphiphilic N-isopropylacrylamide-poly(ethylene glycol)-dodecyl methacrylate thermosensitive polymers

Terpolymers of N-isopropylacrylamide, dodecyl methacrylate (DOMA) and poly(ethylene glycol) (PEG) methacrylate, were synthesized by random copolymerization, and the composition was controlled to achieve systems having different thermosensitivities. H-1 NMR spectra and gel permeation chromatography (GPC) were employed to characterize the different samples obtained. The solution properties were studied by employing spectrophotometry, fluorescence, and dynamic light scattering techniques. The chemical compositions in the final terpolymers are close to those in the feed. The polymers exhibited cloud point temperatures (T-es) varying from 17 to 52 degrees C. Micropolarity studies using I-1/I-3 ratio of the vibronic bands of pyrene show the formation of amphiphilic aggregates capable of incorporating hydrophobic drugs as the polymer concentration is increased. The critical aggregation concentration (CAC) increases from 3.6 x 10(-3) to 1 x 10(-2) g/l with the PEG content varying from 5 to 35 mol%. Anisotropy measurements confirm the results obtained by pyrene fluorescence and show that the aggregates resulting from intermolecular interactions present different organizations. The hydrodynamic diameters (Dh) of the aggregates determined by dynamic light scattering (DLS) vary from 40 to 150 nm depending on the terpolymer composition. The T-cs and Dh values decreased with the ionic strength, and this behavior was attributed to the dehydration of the polymeric micelles. The capacity of solubilization of the aggregates was evaluated by employing pyrene, and the obtained results confirm the ability to incorporate hydrophobic molecules. (c) 2005 Elsevier B.V All rights reserved.

Thermal behavior of residues (sludge) originating from the sugarcane industry

The Brazilian sugarcane industry shows a great amount of generated sludge which should be utilized adequately. Two sludge samples, aerobic and anaerobic, were collected. Both were evaluated by thermogravimetry and differential thermal analysis (DTA) as well as X-ray power diffraction. These compounds show variations of mass between 30 and 140 A degrees C due to the dehydration stage. The DTA curves show that the compounds have an exothermic reaction between 450 and 550 A degrees C, which indicates that this can be used as an energy source. Details concerning the kinetic parameters of the dehydration and thermal decomposition have also been described here. The kinetic study of these stages was evaluated in open crucibles under nitrogen atmosphere. The obtained data were evaluated with the isoconversional kinetic method. The results show that different activation energies were obtained for thermal decomposition.

Preparation of the Ca-diclofenac complex in solid state

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The Interaction Between N-Isopropylacrylamide-Acrylic Acid-Ethyl Methacrylate Thermosensitive Polymers and Cationic Surfactants

The interaction between cationic surfactants and isopropylacrylamide-acrylic acid-ethyl methacrylate (IPA:AA:EMA) terpolymers has been investigated using steady-state fluorescence and spectrophotometric measurements to assess the effect of the polymer composition on the aggregation process and terpolymers' thermosensitivities. Micropolarity studies using pyrene show that the interaction of cationic surfactants with IPA:AA:EMA terpolymers occurs at surfactant concentrations much smaller than that observed for the pure surfactant in aqueous solution. The critical aggregation concentration (CAC) values decrease with both the hydrocarbon length of the surfactant and the content of ethyl methacrylate. These results were interpreted as a manifestation of the increasing contribution of attractive hydrophobic and electrostatic forces between negatively charged polymer chains and positively charged surfactant molecules. The increase of ethyl methacrylate in the copolymers lowers the CAC due to the larger hydrophobic character of the polymer backbone. The cloud point determination reveals that the lower critical solution temperatures (LCST) depend strongly on the copolymer composition and surfactant nature. The binding of surfactants molecules to the polymer chain screens the electrostatic repulsion between the carboxylic groups inducing a conformational transition and the dehydration of the polymer chain.

Ability of different restorative materials to prevent in situ secondary caries: analysis by polarized light-microscopy and energy-dispersive X-ray

Secondary caries is the main cause of direct restoration replacement. The purpose of this study was to analyze enamel adjacent to different restorative materials after in situ cariogenic challenge using polarized-light microscopy (PLM), scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDS). Twelve volunteers, with a low level of dental plaque, a low level of mutans streptococci, and normal salivary flow, wore removable palatal acrylic appliances containing enamel specimens restored with Z250 composite, Freedom composite, Fuji IX glass-ionomer cement, or Vitremer resin-modified glass-ionomer for 14 days. Volunteers dripped one drop of 20% sucrose solution (n = 10) or distilled water (control group) onto each specimen 8 times per day. Specimens were removed from the appliances and submitted to PLM for examination of the lesion area (in mm(2)), followed by dehydration, gold-sputtering, and submission to SEM and EDS. The calcium (Ca) and phosphorus (P) contents were evaluated in weight per cent (%wt). Differences were found between Z250 and Vitremer, and between Z250 and FujiIX, when analyzed using PLM. Energy-dispersive X-ray analysis results showed differences between the studied materials regarding Ca %wt. In conclusion, enamel adjacent to glass-ionomer cement presented a higher Ca %wt, but this material did not completely prevent enamel secondary caries under in situ cariogenic challenge.

Efficiency of ethanol conversion induced by controlled modification of pore structure and acidic properties of alumina catalysts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Obstrução intestinal e enterotomia em tigre d’água (Trachemys dorbignyi)

Intestinal obstruction occurs in chelonian mainly due parasitism and foreign bodies, as stones and sand. An intestinal compaction was described in a five year-old male d'orbigny's slider which was taken to the Veterinary Medical Teaching Hospital of the UNICASTELO, at Fernandopolis, SP, Brazil, presenting anorexia for a week, severe dehydration and stupor. Definitive diagnostic was performed by radiographic exam and great amount of intestinal radiopac substance was detected. The animal went through emergency celiotomy for removing the intestinal foreign bodies. Inhalatory anesthesia with isofluorane was used for anesthesia induction and manutention. After local antisepsy, a 4cm(2) oblique opening was conducted on plastron by using a vibratory saw. Peritoneum was cut, intestines exteriorized and enterotomy performed. During the surgery, the animal was radiographed to confirm the complete taken out of the foreign bodies. Mononylon 4-0 strand was applied for intestinal suture in two planes. The plastron piece that was taken out was replaced and set with epoxy resine and gaze on the surgical window, making it waterproof. In the postoperative time, animal was medicated with analgesics for two days and pentabiotics for five days. Oral creamy diet was used with oral tube from the second to tenth day, what provided a great clinicosurgical recovering.

Quantum Mechanics Insight into the Microwave Nucleation of SrTiO3 Nanospheres

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)