929 resultados para high speed optical switch
Resumo:
Methods based on visual estimation still is the most widely used analysis of the distances that is covered by soccer players during matches, and most description available in the literature were obtained using such an approach. Recently, systems based on computer vision techniques have appeared and the very first results are available for comparisons. The aim of the present study was to analyse the distances covered by Brazilian soccer players and compare the results to the European players', both data measured by automatic tracking system. Four regular Brazilian First Division Championship matches between different teams were filmed. Applying a previously developed automatic tracking system (DVideo, Campinas, Brazil), the results of 55 outline players participated in the whole game (n = 55) are presented. The results of mean distances covered, standard deviations (s) and coefficient of variation (cv) after 90 minutes were 10,012 m, s = 1,024 m and cv = 10.2%, respectively. The results of three-way ANOVA according to playing positions, showed that the distances covered by external defender (10642 ± 663 m), central midfielders (10476 ± 702 m) and external midfielders (10598 ± 890 m) were greater than forwards (9612 ± 772 m) and forwards covered greater distances than central defenders (9029 ± 860 m). The greater distances were covered in standing, walking, or jogging, 5537 ± 263 m, followed by moderate-speed running, 1731 ± 399 m; low speed running, 1615 ± 351 m; high-speed running, 691 ± 190 m and sprinting, 437 ± 171 m. Mean distance covered in the first half was 5,173 m (s = 394 m, cv = 7.6%) highly significant greater (p < 0.001) than the mean value 4,808 m (s = 375 m, cv = 7.8%) in the second half. A minute-by-minute analysis revealed that after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half. ©Journal of Sports Science and Medicine (2007).
Compostos fenólicos e atividade antioxidante de Leiothrix flavescens (Bong.) Ruhland (Eriocaulaceae)
Resumo:
This paper describes a chemical investigation (by high-speed counter-current chromatography) of an extract in methanol of the capitula (flower-heads) of the endemic Brazilian herb Leiothrix flavescens (Bong.) Ruhland (Eriocaulaceae). Fractionation of this extract by preparative chromatography and identification of the isolated compounds by spectrometric methods (IR, UV, ESI-MS, NMR) led to the identification of flavones (apigenin, luteolin and 6-methoxyluteolin) and 1,3-di-O-feruloyl glycerol. The antioxidant activity of the extract was determined by DPPH reduction and the total phenolic content by the Folin-Ciocalteau assay. It was found that the methanolic extract of L. flavescens possesses strong antioxidant activity. Additionally, the chemical profile provided useful data for a discussion of the taxonomy of the Eriocaulaceae.
Resumo:
The aim of this study was to determine the serum activities of enzymes aspartate aminotransferase, creatine kinase and lactate dehydrogenase in Arabian horses submitted to exercise on high-speed equine treadmill. Eleven mature Arabian horse were training and submitted to Standard Incremental Exercise Test on high-speed equine treadmill. Venous blood samples were taken before exercise, immediately and 30 min, 60min, 3h, 6h, 24h, 3 days and 5 days after exercise. The serum activity aspartate aminotransferase, creatine kinase and lactate dehydrogenase were determined. The serum activies of AST, CK and LDH increase immediately and returned to baseline value 30 minutes after exercise. The AST enzyme activity increased at 12 hours and 24 hours, CK at 3 hours and 6 hours, and LDH at 24 hours after Standard Incremental Exercise Test.
Resumo:
There has been a great interest for improving the machining of cast iron materials in the automotive and other industries. Comparative studies for tool used to machine grey cast iron (CI) and compacted graphite iron (CGI) on dry machining were also performed in order to find out why in this case the tool lifetime is not significantly higher. However the machining these materials while considering turning with the traditional high-speed steel and carbide cutting tools present any disadvantages. One of these disadvantages is that all the traditional machining processes involve the cooling fluid to remove the heat generated on workpiece due to friction during cutting. This paper present a new generation of ceramic cutting tool exhibiting improved properties and important advances in machining CI and CGI. The tool performance was analyzed in function of flank wear, temperature and roughness, while can be observed that main effects were found for tool wear, were abrasion to CI and inter-diffusion of constituting elements between tool and CGI, causing crater. However the difference in tool lifetime can be explained by the formation of a MnS layer on the tool surface in the case of grey CI. This layer is missing in the case of CGI.
Resumo:
The current study evaluated equine gas exchange responses through spirometry, by measuring oxygen uptake (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (R) and maximum oxygen uptake (VO2max) of Arabian horses during a standard incremental exercise test performed on a high-speed treadmill. Six clinically healthy Arabian horses were submitted to a standard incremental exercise test, performed on a high-speed treadmill at a 6% slope, and initial speed of 1,8 m.s-1 for 5 minutes, then 4,0 m.s-1 for 3 minutes, 6,0 m.s-1 for 2 minutes and 8,0 m.s-1, 9,0 m.s-1, 10,0 m.s-1 and 11,0 m.s-1 for one minute for each of these speed. The end of the exercise test was defined as the point in which the horse was no longer able to keep pace with the treadmill. Gas exchange was measured through respiratory analyses horse mask on the last 10 seconds at the end of each speed transition and at 1, 2 and 3 minutes after the end of the exercise, defined as experiment moments. During exercise, it was noticed an increase on both VO2 and VCO2 with linear relationship between exercise and speed. Arabian horses VO2max was 114,9 mL.kg-1.min-1. The respiratory exchange ratio increased over 1,0 by the speed of 9,0 m.s-1, indicating the preponderance of the anaerobic metabolism, and remains at a high level on the post-exercise period.
Resumo:
The effect of physical exercise, training and vitamin E supplementation on electrocardiographic parameters was evaluated in eight untrained Arabian mares, divided into two groups: control (n=4) and supplemented with vitamin E (n=4) at the daily dose of 1.000 UI. Animals were submitted to an incremental exercise test (P1) on high-speed treadmill inclined +7%, after that to a training period of 20 days and later to a new incremental exercise test (P2). Analysis and interpretation of electrocardiographic tracings were performed regarding the rhythm, heart rate, duration and amplitude of waves and intervals, before, immediately after and 30 min after the incremental exercise. A reduction of the rest heart rate was observed after training. There was no effect of vitamin E supplementation on electrocardiographic parameters. Results indicated that the electrocardiogram was efficient in detention of cardiac alterations promoted by the physical exercise, but more studies are needed to elucidate its clinical meaning.
Resumo:
This study evaluated the Influence of the coloring agent concentration on the temperature of the gel layer and pulp chamber during dental bleaching with an LED/laser light source. Ten human incisors and a digital thermometer with K-type thermocouples were used. Using a high-speed spherical diamond bur, endodontic access was gained through openings on the lingual faces until pulp chamber was exposed. One end of the thermocouple was placed on the labial surface (immersed in bleaching gel) and the other end in the pulp chamber. The same 10 specimens were used in the 12 groups, according to the type and concentration of bleaching gel. Each bleaching gel was used in four different concentrations: manipulated without coloring, with normal quantity recommended by the manufacturer, with double the recommended amount of coloring, and with triple the recommended amount of coloring. The temperature rise was measured every 30 seconds for three minutes with a K-type thermocouple. The data were analyzed by ANOVA to examine the concentration and type of bleaching gel. This test was followed by Tukey's test, which was performed Independently for the gel at the labial surface and the pulp chamber (a = 5%). For both surfaces, values of p = 0.00 were obtained for all factors and for the Interaction between them. The varying concentrations of coloring agent produced statistically significant differences in terms of temperature increase for both the gel layer and the pulp chamber during activation.
Resumo:
OBJECTIVES: The purpose of this in vitro study was to quantify the alterations in human root dentin permeability after exposure to dietary acids and to evaluate the effect of toothbrushing after acid application. METHOD AND MATERIALS: Extracted human third molars had their crowns sectioned above the CEJ, pulp tissue removed, and cervical root dentin exposed using a high-speed bur (approximately 1 mm in depth of substance loss). From each root fragment, one specimen was prepared. A total of 25 specimens were used and distributed randomly into five groups. The specimens were attached to a hydraulic pressure apparatus to evaluate the alterations of root dentin permeability after exposure to different acids. Dentin permeability was measured after the following sequential steps: (1) treatment with EDTA for 3 minutes to obtain the maximum permeability; (2) root planing to create a smear layer; (3) exposure to different acidic substances for 5 minutes (vinegar, cola drink, lemon juice, white wine, and orange juice); and (4) brushing for 3 minutes. RESULTS: All acidic substances increased dentin permeability after root planing. Lemon juice produced higher values for permeability when compared to the other substances (P = .009); moreover, orange juice showed similar results (P < .02) except when compared to vinegar (P = .12). Brushing right after acid exposure significantly reduced dentin permeability except in the vinegar group (P = .07). CONCLUSION: Under the experimental conditions, dietary acids increased root dentin permeability, and immediate brushing reduced permeability levels.
Resumo:
The influence of the type of rotary cutting instrument on bone repair after osteotomy in swine jaw, was evaluated using digital and densitometric radiographic examinations, at controlled times. Two cross-sectional dissections were made through the base of the right jaw, one using a high speed rotary instrument and the other using low speed, both with liquid cooling. After established periods the animals were sacrificed and their jaws removed for direct and indirect digital radiographic and densitometric studies using the CROMOX, DIGORA and ODR systems. In the initial periods (7 and 28 days) the bone density was higher in osteotomy areas performed with high rotation speeds, and in the final periods (60 and 90 days) the bone density was higher in the osteotomies performed with low rotation, indicating a better final bone repair with the use of low rotation. The qualitative analysis of the repair process was made by the ODR system which obtained three-dimensional and coloured digital images, which enable the bone thickness to be measured using an aluminium wedge. This showed that by twenty-eight days the bone repair was already apparently complete. © 2010 SECOM.
Resumo:
Includes bibliography
Resumo:
The aim of this paper was to compare the dentin-pulp complex response to cavity preparation in human teeth using ultrasonic chemical vapor deposition (CVD) diamond tip and high-speed diamond bur. Class V buccal cavities were randomly prepared in 40 premolars from 14 patients aged 11 to 15 years. The cutting time was recorded and the cavities had the axial walls protected with gutta-percha and were filled with glass ionomer cement. The teeth were extracted at intervals of 0, 5, 10 and 20 days, and were decalcified, sectioned and stained by Hematoxylin & Eosin, Masson's Trichrome and Brown & Brenn techniques. The inflammatory response and cell disorganization were blindly evaluated by two examiners. The remaining dentin thickness (RDT) was measured by a linear scale using computer software. Statistical analysis by one-way ANOVA showed no statistically significant difference (P≤0.05) among the cavities prepared with either type of instrument, with mean RDT of 1132.50 mm. Cutting time and the pulp-dentin complex responses were analyzed statistically by Kruskal-Wallis and Dunn tests (P≤0.05). The ultrasonic CVD diamond tip took 5 times longer to prepare the cavities and there were no typical inflammatory pulp responses in cavities prepared with either type of cutting instrument, only mild to moderate cell disorganization was present. Even taking longer to cut the dental substrate, the ultrasonic CVD diamond tip produced similar pulp response compared to the conventional high-speed diamond bur.
The influence of grain size coating and shaft angulation of different diamond tips on dental cutting
Resumo:
Objectives: To evaluate the influence of the grain size coating and shaft angulation of ultrasonic and high-speed diamond burs on the dental cutting effectiveness. Materials and Methods: For the grain size evaluation, cavities were prepared on 40 incisors using high-speed (1092 and 1093F KG Sorensen®) and ultrasonic tips (8.2142 and 6.2142-CVDentus®). For the shaft angulation evaluation, cavities were prepared on 40 incisors using uniangulated (T1-CVDentus®) and biangulated (T1-A CVDentus®) ultrasonic tips. The cavities were bisected and examined at 50 magnification. The width and depth of cavities were measured by Leica QWin software. Kruskal-Wallis non-parametric test was used for analysis. Results: The grain size did not affect the cutting effectiveness, but the high-speed burs promoted deeper and wider cavities than the ultrasonic tips. The shaft angulation did not affect the cutting effectiveness; both the angulated and biangulated tips had greater cutting efficiency in dentin than in enamel. Conclusions: Ultrasonic tips promoted more conservative preparations and seemed promising for cavity preparation.
Resumo:
Introduction: An appropriate selection of instruments is essential to perform a correct debonding technique, by properly removing orthodontic brackets and the remaining resin. Objective: The aim of this study was to evaluate three methods of remaining resin removal on enamel surface after bracket debonding, by means of Scanning Electron Microscopy (SEM). Methods: Eighteen bovine incisors were selected and divided into three groups (A, B and C) of six teeth each. Before bracket bonding, epoxy resin casts were obtained by impression of the teeth with addition silicon, in order to register baseline enamel characteristics and representing the control group. The methods for remaining resin removal were: Group A - gross and medium granulation Soflex discs; Group B - carbide bur in low-speed; Group C - carbide bur in high-speed. Soflex polishing system fine and ultrafine granulation discs were used for Group A, rubber tips for Groups B and C, and polishing paste for all groups. After polishing, impression of teeth were taken and casts were analyzed by means of SEM. The baseline enamel characteristics (Control Group) were compared to the final aspect of enamel to determine the method that generated less enamel abrasion. Results and Conclusion: The remaining resin removal by carbide bur in low-rotation, and enamel polished with rubber tips followed by polishing paste produced the smaller damage to the enamel.
Resumo:
Includes bibliography
Resumo:
Taking into account the bone repair process in pigs has shown a greater similarity among the histological variables studied compared to other biological models, the present study has as its aim to evaluate the histological bone repair process of osteotomy performed on alveolar and extra-alveolar bones, using drilling tools with liquid refrigeration. Material and method: Eighteen Large White pigs weighing between 20 and 25 Kg were divided into three groups of six animals in order to evaluate the osteotomy repairs with low and high speed in the alveolar bone and threes in the extra-alveolar area, study periods of 7, 14 and 28 days. Results: It was observed that in the alveolar bone at the postoperative times of 14 and 28 days, the best repair results were in the osteotomy performed with low speed, while in the 7 day postoperative period, the results with high speed were slightly better, in alveolar areas as well as extra-alveolar areas. There no statistically significant differences between the alveolar and extra-alveolar bone repair process. Conclusions: The repair process, by means of microscopic analysis in the alveolar and extra-alveolar areas, are similar with better results observed in osteotomies performed with low speed drills in the 14 and 28 day study periods, and at 7 days postoperative the results with high speed drills and refrigeration were slightly better. Research works using pigs as an animal model are perfectly viable. © 2011 SECOM.