Decay resistance of thermally-modified Eucalyptus grandis wood at 140 degrees C, 160 degrees C, 180 degrees C, 200 degrees C and 220 degrees C

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

Electrochemical sensor for sulfite determination based on a nanostructured copper-salen film modified electrode

The electrochemical preparation described herein involved the electrocatalytic oxidation of sulfite on a platinum electrode modified with nanostructured copper salen (salen=N,N'-ethylenebis(salicylideneiminato)) polymer films. The complex was prepared and electropolymerized at a platinum electrode in a 0.1 mol L-1 solution of tetrabutylammonium perchlorate in acetonitrile by cyclic voltammetry between 0 and 1.4V vs. SCE. After cycling the modified electrode in a 0.50 mol L-1 KCI solution, the estimated surface concentration was found to be equal to 2.2 x 10(-9) Mol cm(-2). This is a typical behavior of an electrode surface immobilized with a redox couple that can usually be considered as a reversible single-electron reduction/oxidation of the copper(II)/copper(III) couple. The potential peaks of the modified electrode in the electrolyte solution (aqueous) containing the different anions increase with the decrease of the ionic radius, demonstrating that the counter-ions influence the voltammetric behavior of the sensor. The potential peak was found to be linearly dependent upon the ratio [ionic charge]/[ionic radius]. The oxidation of the sulfite anion was performed at the platinum electrode at +0.9V vs. SCE. However, a significant decrease in the overpotential (+0.45V) was obtained while using the sensor, which minimized the effect of oxidizable interferences. A plot of the anodic current vs. the sulfite concentration for chronoamperometry (potential fixed = +0.45V) at the sensor was linear in the 4.0 x 10(-6) to 6.9 x 10(-5) mol L-1 concentration range and the concentration limit was 1.2 x 10(-6) mol L-1. The reaction order with respect to sulfite was determined by the slope of the logarithm of the current vs. the logarithm of the sulfite concentration. (C) 2009 Elsevier Ltd. All rights reserved.

Phytase immobilization on modified electrodes for amperometric biosensing

Phytase (myo-inositol hexaphosphate phosphohydrolase) and phytic acid (myo-inositol hexaphosphate) play an important environmental role, in addition to being a health issue in food industry. Phytic acid is antinutritional due to its ability to chelate metal ions and may also react with proteins decreasing their bioavailability. In this work, we produced biosensors with phytase immobilized in Layer-by-Layer (LbL) films, which could detect phytic acid with a detection limit of 0.19 mmol L-1, which is sufficient to detect phytic acid in seeds of grains and vegetables. The biosensosrs consisted of LbL films containing up to eight bilayers of phytase alternated with poly(allylamine) hydrochloride (PAH) deposited onto an indium-tin oxide (ITO) substrate modified with Prussian Blue. Amperometric detection was conducted in an acetate buffer solution (at pH 5.5) at room temperature, with the biosensor response attributed to the formation of phosphate ions. In subsidiary experiments with the currents measured at 0.0 V (vs. SCE), we demonstrated the absence of effects from some interferents, pointing to a good selectivity of the biosensor. (c) 2007 Elsevier B.V. All rights reserved.

Voltammetric performance and application of a sensor for sodium ions constructed with layered birnessite-type manganese oxide

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparação e mobilidade, equilíbrio corporal e desempenho muscular segundo a auto-eficácia para quedas em idosas

The aging process modifies various systems in the body, leading to changes in mobility, balance and muscle strength. This can cause a drop in the elderly, or not changing the perceived self-efficacy in preventing falls. Objective: To compare the mobility, body balance and muscle performance according to self-efficacy for falls in community-dwelling elderly. Methods: A cross-sectional comparative study with 63 older (65-80 years) community. Were evaluated for identification data and sociodemographic, cognitive screening using the Mini Mental State Examination (MMSE), effective for the fall of Falls Efficacy Scale International Brazil (FES-I-BRAZIL), Mobility through the Timed Up and Go Test , the balance Berg Balance Scale (BBS) and the Modified Clinical Test tests of Sensory Interaction on Balance (mCTSIB), tandem walk (TW) and Sit to Stand (STS) of the Balance Master® System. Finally, muscle performance by using isokinetic dynamometry. Statistical analysis was performed Student t test for comparison between groups, with p value ≤ 0.05. Results: Comparing the elderly with low-efficacy for falls with high-efficacy for falls, we found significant differences only for the variable Timed Up and Go Test (p = 0.04). With regard to data on balance tests were significant differences in the speed of oscillation firm surface eyes open modified Clinical Test of Sensory Interaction on Test of Balance (p = 0.01). Variables to isokinetic dynamometry were no significant differences in movement knee extension, as regards the variables peak torque (p = 0.04) and power (p = 0.03). Conclusion: The results suggest that, compared to older community with low-and high-efficacy for falls, we observed differences in variables related to mobility, balance and muscle function

Use of scrap tire rubber in place of SBS in modified asphalt as an environmentally correct alternative for Brazil

Reusing scrap tires has become a worldwide challenge, especially due to the great difficulty in finding ecologically and economically feasible ways to dispose of them. This has led to the creation of specific programs and legislation for reusing scrap tires. Research has shown that a certain percentage of scrap tire rubber can be added to asphalt compositions, and this has become a worldwide practice. This paper describes the properties of four asphalt compositions modified with scrap tire rubber (STR) prepared in the laboratory. These properties are then compared with those of asphalt modified with styrene butadiene styrene (SBS), a synthetic polymer and one of the most common modifiers, to verify the feasibility of using scrap tire rubber as a substitute for SBS. The scope of this study does not include an analysis of how STR affects end-of-life asphalt. The main findings indicate that STR is a potential substitute of SBS in paving material, and although it does not meet some of the standard specifications when compared with SBS, these issues can be overcome by proper care during storage and transportation. The substitution of SBS by STR also showed the potential for about 10% in expenditure savings. (C) 2012 Elsevier Ltd. All rights reserved.

Ferrocene adsorbed into the porous octakis(hydridodimethylsiloxy) silsesquioxane after thermolysis in tetrahydrofuran media: An applied surface for ascorbic acid determination

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

Cellulose nanowhiskers from coconut husk fibers: Effect of preparation conditions on their thermal and morphological behavior

Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis from coconut husk fibers which had previously been submitted to a delignification process. The effects of preparation conditions on the thermal and morphological behavior of the nanocrystals were investigated. Cellulose nanowhisker suspensions were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X-ray diffraction. Results showed that it was possible to obtain ultrathin cellulose nanowhiskers with diameters as low as 5 nm and aspect ratio of up to 60. A possible correlation between preparation conditions and particle size was not observed. Higher residual lignin content was found to increase thermal stability indicating that by controlling reaction conditions one can tailor the thermal properties of the nanowhiskers. Published by Elsevier Ltd.

Psycholinguistic abilities of children with Williams syndrome

The objective of this study was to investigate the psycholinguistic abilities of children with Williams syndrome (WS) and typically developing children using the Illinois Test of Psycholinguistic Abilities (ITPA). Performance on the ITPA was analysed in a group with WS (N = 20, mean age = 8.5 years, SD = 1.62) and two typically developing groups, matched in mental (MA, N = 20, mean age = 4.92 years, SD = 1.14) and chronological age (CA, N = 19, mean age = 8.35 years, SD = 3.07). Overall, within-group analyses showed that individuals with WS displayed higher scalar scores on the visual reception and visual association subtests. When groups were compared, we observed inferior performance of the WS group on all ITPA subtests when compared with typically developing groups. Moreover, an interaction between reception and group was found, only the WS group demonstrated superior performance on the visual reception subtest when compared to the auditory reception subtest. Evidence from this study offers relevant contributions to the development of educational intervention programs for children with WS. (C) 2011 Elsevier Ltd. All rights reserved.

O bloqueio do sistema renina-angiotensina atenua a remodelação cardíaca de ratos submetidos a estenose aórtica

OBJETIVO: Avaliar o papel do bloqueador dos receptores AT1 e do inibidor da enzima conversora da angiotensina na remodelação cardíaca induzida por estenose aórtica em ratos. MÉTODOS: Ratos Wistar foram divididos em 4 grupos: controle (C, n=13), estenose aórtica (EAo, n=11), EAo com lisinopril, 20 mg/kg/dia (LIS, n=11) e EAo com losartan, 40 mg/kg/dia (LOS, n=9). Os tratamentos foram iniciados 3 dias antes da cirurgia. Após 6 semanas, os animais foram submetidos ao estudo ecocardiográfico, quantificação da concentração de hidroxiprolina e da área seccional (CSA) miocitária do ventrículo esquerdo (VE). RESULTADOS: A EAo induziu aumento da espessura da parede do VE. Os animais LIS e LOS não apresentaram diferença em relação aos animais controles. Os ratos EAo e LIS apresentaram maiores diâmetros do átrio esquerdo que os ratos controles, enquanto nos animais LOS não houve diferença. Os animais com EAo apresentaram maiores valores da porcentagem de encurtamento que os controle. Esse fato não foi modificado com LIS ou LOS. A CSA dos animais do grupo EAo foi maior que a dos controle. Entretanto, o tratamento com LOS e com LIS atenuou o aumento da área induzida pela EAo. A EAo resultou em aumento na concentração de HOP, enquanto o grupo LOS não apresentou diferença em relação ao grupo controle. CONCLUSÃO: O bloqueio do sistema renina-angiotensina, com bloqueador AT1 e com IECA, pode atenuar o desenvolvimento de hipertrofia cardíaca, porém só o bloqueio dos receptores AT1 atenua a fibrose intersticial do VE.

Association of dyslipidemia with intakes of fruit and vegetables and the body fat content of adults clinically selected for a lifestyle modification program

To investigate the relationship of dyslipidemia with demographic distribution and patterns of body fat and dietary intakes. From a universe of adults clinically selected for a lifestyle modification program 979 subjects (409 males and 570 females, 52.2 +/- 9.6 years) fulfilled the inclusion criteria. Overnight-fasting plasma was assayed (dry chemistry) for triglycerides (TG), total (TC) and HDL fraction of cholesterol given the non-HDL (n-HDL) fraction by the difference. Anthropometric assessment included body weight (kg), height (m), fat (bioelectrical impedance) and waist circumference (WC). Food intake was assessed by the 24-hour recall questionnaire and the food groups evaluated through recommendations from an adapted food pyramid. The chances of dyslipidemia from other variable changes were determined by logistic regression with p < 0.05. Normal values of BMI and WC were protective against all dyslipidemia markers whereas only hypercholesterolemia was influenced by diet (meat intake > 2 servings). Dietary intakes have protective effects against hypertriglyceridemia with whole grains, odds ratio (OR) 0.342 (Cl 95%, 0.154-0.760), fruits >= 3 servings (OR 0.523, 0.290-0.941) and vegetables >= 4 servings (OR 0.360, 0.176-0.735). In general total body and abdominal adiposity influenced all dystipidemia markers while dietary intake of fruits and vegetables protected against triglyceridemia.

Increased plasma and salivary cortisol levels in patients with oral cancer and their association with clinical stage

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

Reaction of the lateral periodontium of dogs' teeth to contaminated and noncontaminated perforations filled with mineral trioxide aggregate

It has been shown that the mineral trioxide aggregate (MTA) used to seal lateral/furcal perforations stimulates the deposition of newly formed cementum. Nevertheless, when the site of the perforation is contaminated, the healing process might occur under less favorable conditions. This study evaluated the repair healing process of noncontaminated and contaminated lateral perforations filled with MTA and the effect of previously filling the contaminated perforations with a bactericidal agent. Thirty lateral root perforations were prepared in endodontically treated dog's teeth, thus forming 3 groups with 10 specimens each. In group 1 the perforations were immediately sealed with MTA. In group 2 the perforations were left open for 7 days and thereafter sealed with MTA. In group 3 the perforations were left open for 7 days, filled temporarily with a calcium hydroxide-based paste for 14 days, and then sealed with MTA. The animals were killed after 90 days, and the pieces were prepared for histomorphologic and histomicrobiologic evaluations. The statistical analysis showed that group 1 had significantly better repair than groups 2 (P <.05) and 3 (P <.05), which validates the superior results obtained when MTA was immediately used to seal root perforations. Groups 2 and 3 had statistically similar repair to each other (P >.05). There were a larger number of cases of complete or partial biologic seal in group 1 compared with the contaminated groups. It might be concluded that the lateral root perforations sealed with MTA after contamination presented worse repair than the noncontaminated, immediately sealed perforations. The temporary filling with a bactericidal agent (calcium hydroxide-based paste) did not improve the repair of perforations exposed to contamination, and the contaminated groups presented similar results to each other.

Saliva substitute in combination with high-concentrated fluoride toothpaste: Effects on demineralised dentin in vitro

Objectives: The aim of this in vitro study was to assess the effects of saliva substitutes (modified with respect to calcium, phosphates, and fluorides) in combination with a high-concentrated fluoride toothpaste on demineralised dentin.Methods: Before and after demineralisation of bovine dentin specimens (subsurface lesions; 37 degrees C, pH 5.0, 5 d), one-quarter of each specimen's surface was covered with nail varnish (control of sound/demineralised tissue). Subsequently, specimens were exposed to original Saliva natura (saturation with respect to octacalciumphosphate [S(OCP)]: 0.03; SN 0), or to three lab-produced Saliva natura modifications (S(OCP): 1, 2, and 3; SN 1-3) for 2 and 5 weeks (37 degrees C). An aqueous solution (S(OCP): 2.5) served as positive control (PC). Two times daily (2 min each), Duraphat toothpaste (5000 ppm F(-); Colgate)/saliva substitute slurry (ratio 1:3) was applied gently. Differences in mineral losses (Delta Delta Z) and lesion depths (Delta LD) between values before and after exposure were microradiographically evaluated.Results: After both treatment periods specimens immersed in SN 0 revealed significantly higher mineral losses (lower Delta Delta Z values) and lesion depths (lower Delta LD) compared to PC (p < 0.05; ANOVA). After 5 weeks, specimens stored in SN 1 and 2 showed significantly higher mineral losses compared to PC (p < 0.05), while those stored in SN 3 showed similar results (p > 0.05). No differences in mineral loss could be observed between SN 2 and 3 (p > 0.05).Conclusions: Under the conditions of this limited protocol, the combination of Saliva natura solutions slightly saturated with respect to OCP in combination with a high-concentrated fluoride toothpaste enabled remineralisation of dentin in vitro. Crown Copyright (c) 2009 Published by Elsevier Ltd. All rights reserved.

Comparison between apo and complexed structures of bothropstoxin-I reveals the role of Lys122 and Ca2+-binding loop region for the catalytically inactive Lys49-PLA(2)s

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