Survival rate, load to fracture, and finite element analysis of incisors and canines restored with ceramic veneers having varied preparation design

Purpose: To evaluate the survival rate, success rate, load to fracture, and finite element analysis (FEA) of maxillary central incisors and canines restored using ceramic veneers and varying preparation designs.Methods and Materials: Thirty human maxillary central incisors and 30 canines were allocated to the following four groups (n=15) based on the preparation design and type of tooth: Gr1 = central incisor with a conservative preparation; Gr2 = central incisor with a conventional preparation with palatal chamfer; Gr3 = canine with a conservative preparation; Gr4 = canine with a conventional preparation with palatal chamfer. Ceramic veneers (lithium disilicate) were fabricated and adhesively cemented (Variolink Veneer). The specimens were subjected to 4 x 106 mechanical cycles and evaluated at every 500,000 cycles to detect failures. Specimens that survived were subjected to a load to fracture test. Bidimensional models were modeled (Rhinoceros 4.0) and evaluated (MSC.Patrans 2005r2 and MSC.Marc 2005r2) on the basis of their maximum principal stress (MPS) values. Survival rate values were analyzed using the Kaplan-Meier test (alpha = 0.05) and load to fracture values were analyzed using the Student t-test (alpha = 0.05).Results: All groups showed 100% survival rates. The Student t-test did not show any difference between the groups for load to fracture. FEA showed higher MPS values in the specimens restored using veneers with conventional preparation design with palatal chamfer.Conclusion: Preparation design did not affect the fracture load of canines and central incisors, but the veneers with conventional preparation design with palatal chamfer exhibited a tendency to generate higher MPS values.

Influência do alongamento prévio no pico de torque e na taxa de força em exercício de contração isométrica

The objective of this study was to investigate the influence of previous active static stretch on the isometric peak torque (PT) and rate of force development (RFD) measured from different time intervals from the beginning of muscle contraction. Participated of this study 15 male individuals, apparently healthy, with ages between 18 and 25 years, without regular physical activity practice. The individuals were submitted in different days to the following tests: 1) Familiarization session to the isokinetic dynamometer; 2) Two maximal isometric concentric contractions for knee extensors in isokinetic dynamometer to determine PT and RFD (Control), and; 3) Two active static stretching exercises for the dominant leg extensors (10 x 30 s for each exercise, with 20 s of rest). After the stretching, the isokinetic test was repeated (Post-Stretching). The conditions 2 and 3 were performed in random order. The RFD was considered as the mean slope of the moment-time curve at time intervals of 0-30, 0-50 and 0-100ms relative to the beginning of muscle contraction. It was verified significant reduction for both maximal RFD and PT after the stretching (p < 0.05). At intervals of 0- 30ms, 0-50ms and 0-100ms, the RFD at the conditions with stretching was similar to the RFD without stretching (p > 0.05). At intervals of 0-150ms and 0-200ms, the RFD obtained at the contraction without stretching was significantly higher that that obtained at the contraction with stretching (p < 0.05). It can be concluded that the static stretching, performed with duration of 600 s diminish isometric PT, maximal RFD and RFD measured at late phase (> 100 ms) of muscle contraction.

Perfil hematológico de cabras Saanen e mestiças (1/2 Saanen e 1/2 Anglo-nubiana) criadas em clima tropical do Ceará

The aim of this study was to determine the influence of climatic conditions on the hematological profile of Saanen and mixed-breed (1/2 Saanen x 1/2 Anglo-Nubian) goats, as well as to define reference values for these animals bred in Ceara, Brazil. Thirty goats were utilized and blood samples were collected monthly during the rainy (February to May) and dry (August to November) periods to obtain an erythrogram a leukogram. The averange were compared by the t-Student test and Mann Whitney test, with parametric and non-parametric distribution of the data, respectively, where p<0.05 was considered significant. A study was carried out of simple Pearson correlations of the hematological parameters with environmental and physiological variables. The number of red blood cells (RBCs) was higher in the Saanen goats and in the rainy period, while the hematocrit was higher in the dry period (p<0.05). The leukocytes and lymphocytes were higher in the 1/2S1/2 AN goats in the two periods (p<0.05). In the two genotypes, the leukocytes and lymphocytes were higher in the dry season and the segmented neutrophils higher in the rainy season (p<0.05). The other parameters did not differ (p>0.05). The RBCs and segmented neutrophils displayed a negative correlation with air temperature, but positive with relative humidity and rectal temperature (p<0.05). The hematocrit positively correlated with air temperature and respiratory rate (p<0.05). The leukocytes and lymphocytes showed a negative correlation with rectal temperature (p<0.05). It was therefore concluded that Saanen females are more affected by climatic variations and that the rainy season has a greater negative impact on hematological parameters. The values obtained could serve as a reference for these genotypes in Ceara.

Correlation between heart rate variability indexes and aerobic physiological variables in patients with COPD

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

Maximal Oxygen uptake cannot be determined in the incremental phase of the lactate minimum test on a cycle ergometer

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

Effect of an acute β-adrenergic blockade on the blood glucose response during lactate minimum test

The aim of this study was to determine the relationship between blood lactate and glucose during an incremental test after exercise induced lactic acidosis, under normal and acute β-adrenergic blockade. Eight fit males (cyclists or triathletes) performed a protocol to determine the intensity corresponding to the individual equilibrium point between lactate entry and removal from the blood (incremental test after exercise induced lactic acidosis), determined from the blood lactate (Lacmin) and glucose (Glucmin) response. This protocol was performed twice in a double-blind randomized order by ingesting either propranolol (80 mg) or a placebo (dextrose), 120 min prior to the test. The blood lactate and glucose concentration obtained 7 minutes after anaerobic exercise (Wingate test) was significantly lower (p<0.01) with the acute β-adrenergic blockade (9.1±1.5 mM; 3.9±0.1 mM), respectively than in the placebo condition (12.4±1.8 mM; 5.0±0.1 mM). There was no difference (p>0.05) between the exercise intensity determined by Lacmin (212.1±17.4 W) and Glucmin (218.2±22.1 W) during exercise performed without acute β-adrenergic blockade. The exercise intensity at Lacmin was lowered (p<0.05) from 212.1±17.4 to 181.0±15.6 W and heart rate at Lacmin was reduced (p<0.01) from 161.2±8.4 to 129.3±6.2 beats min-1 as a result of the blockade. It was not possible to determine the exercise intensity corresponding to Glucmin with β-adrenergic blockade, since the blood glucose concentration presented a continuous decrease during the incremental test. We concluded that the similar pattern response of blood lactate and glucose during an incremental test after exercise induced lactic acidosis, is not present during β-adrenergic blockade suggesting that, at least in part, this behavior depends upon adrenergic stimulation.

Effect of hexadecyltrimethylammonium bromide-based microemulsions on the rate of decomposition of the beta-lactam antibiotic cephaclor

Microemulsions of hexadecyltrimethylammonium bromide (HTAB)/n-butanol/hexadecane/water catalyze the intramolecular degradation of cephaclor. The rate increase is a sensitive function of the microemulsion volume fraction and salt concentration. The effects of microemulsions, analyzed quantitatively using a pseudophase ion-exchange model, assumed that the extent of ion dissociation from the microemulsions varies with volume fraction. Comparison of micellar and microemulsion effects on the same reaction shows that microemulsions are less effective catalysts. Acceleration decreased significantly by increasing the relative proportion of n-butanol ratio in microemulsions and by addition of n-butanol in HTAB micelles. Comparison of the activation parameters of the reaction in aqueous solution, microemulsions, and micelles suggests that catalysis by both aggregates is driven mainly by entropic contributions.

Fluorescent antibody test, quantitative polymerase chain reaction pattern and clinical aspects of rabies virus strains isolated from main reservoirs in Brazil

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

Maximal power output during incremental cycling test is dependent on the curvature constant of the power-time relationship

The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.

Exercise tolerance can be enhanced through a change in work rate within the severe intensity domain: work above critical power is not constant

The characterization of the hyperbolic power-time (P-tlim) relationship using a two-parameter model implies that exercise tolerance above the asymptote (Critical Power; CP), i.e. within the severe intensity domain, is determined by the curvature (W') of the relationship. The purposes of this study were (1) to test whether the amount of work above CP (W>CP) remains constant for varied work rate experiments of high volatility change and (2) to ascertain whether W' determines exercise tolerance within the severe intensity domain. Following estimation of CP (208 ± 19 W) and W' (21.4 ± 4.2 kJ), 14 male participants (age: 26 ± 3; peak [Formula: see text]: 3708 ± 389 ml.min-1) performed two experimental trials where the work rate was initially set to exhaust 70% of W' in 3 ('THREE') or 10 minutes ('TEN') before being subsequently dropped to CP plus 10 W. W>CP for TEN (104 ± 22% W') and W' were not significantly different (P>0.05) but lower than W>CP for THREE (119 ± 17% W', P<0.05). For both THREE (r = 0.71, P<0.01) and TEN (r = 0.64, P<0.01), a significant bivariate correlation was found between W' and tlim. W>CP and tlim can be greater than predicted by the P-tlim relationship when a decrement in the work rate of high-volatility is applied. Exercise tolerance can be enhanced through a change in work rate within the severe intensity domain. W>CP is not constant.

Impact of obesity on autonomic modulation, heart rate and blood pressure in obese young people

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Própolis na dieta de abelhas Apis mellifera L. e seu efeito no sistema imune, expressão de genes após o desafio bacteriano e detoxificação frente ao agroquímico fipronil

Pós-graduação em Zootecnia - FMVZ

Análise da modulação autonômica em repouso e em resposta ao Tilt Test ativo em crianças com diabetes tipo 1

Pós-graduação em Fisioterapia - FCT

Comparison of anaerobic threshold, oxygen uptake and heart rate between specific table

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reproducibility of heart rate and rating of perceived exertion values obtained from different incremental treadmill tests

Objective The present study aimed to examine the reproducibility of heart rate (HR) and rating of perceived exertion (RPE) values obtained during different incremental treadmill tests. Equipment and methods Twenty male, recreational, endurance-trained runners (10-km running pace: 10–15 km·h−1) performed, in a counterbalanced order, three continuous incremental exercise tests with different speed increments (0.5 km·h−1, 1 km·h−1 and 2 km·h−1). Thereafter, each participant performed the three tests again, maintaining the same order as before. The reproducibility of the HR and RPE values were analyzed for all protocols during submaximal intensities (8, 10, 12, and 14 km·h−1). In addition, it was examined the reproducibility of maximal HR (HRmax) and peak RPE (RPEpeak). Results The variability of both the HR and RPE values showed a tendency to decrease over the stages during the incremental test and was not or slightly influenced by the incremental test design. The HR at 14 km·h−1 and HRmax presented the highest reproducibility (CV < 2%). In contrast, the submaximal RPE values showed higher variability indices (i.e., CV > 5.0%). In conclusion, the HR values were highly reproducible during the stages of the incremental test, in contrast to the RPE values that presented limited reproducibility.