71 resultados para Power Doppler ultrasound


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Pós-graduação em Fisiopatologia em Clínica Médica - FMB

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The process of spermatic division and differentiation (spermatogenesis) occurs with intratesticular temperature lower that the corporal temperature and for that is essential that the testicular thermoregulation mechanism occurs properly. For evaluation of the scrotal surface temperature can be used the infrared thermography or testicular sensors, besides that, can be evaluated the blood flux in the spermatic cord through the Doppler ultrasonography. Thus, the aim of this study is to analyze the testicular thermoregulation in adult buffaloes through scrotal thermography and Doppler ultrasound of testicular artery and verify its effect on sperm quality. For that were used seven healthy buffaloes, with age of 3 and 4 years, of the Murrah breed. The animals were subjected to 3 semen collections using artificial vagina, with one day of interval. In addiction, the retal temperature measurement (RT) with dry bulb thermometer, the measurement of scrotal surface temperature (SST) and body surface temperature (BST) through infrared thermography and the pulsatility (PI) and resistivity (RI) index of testicular artery by Doppler ultrasonography, were performed using 2 distinct moments: animals previously placed to shade (M1) and animals subjected to 4 hours of sun (M2). All parameters were compared by T test and the correlations were performed by Pearson test using the In Stat Graph Pad 3 (R) program. The significant level considered was 5%. There was an increase (p<0,05) of RT, SST, SNT and RI in M2. increasing trend was observed (0,05>p>0,01) PI and RI between M1 and M2. There was a low correlation between SST and semen quality. The results of this study allow us to conclude that adult buffaloes have low ability to perform body and testicular thermoregulation in situations of enviromental heat stress. However, this low capacity of testicular temperature maintenance demonstrated no correlation with the sperm kinetic parameters and sperm morphological defects in buffalo spermatozoa.

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

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Portal hypertension (PH) is the pathological increase in portal vein pressure above normal limits. Two variables control the pressure in the portal system: the resistance to blood flow and blood flow volume in the portal system. If one these variables changes, PH may develop. Classification: Pre-hepatic (e. g. compression of the portal vein), intrahepatic (e. g. chronic hepatitis and cirrhosis) or post-hepatic (e. g. right heart failure). The invasive methods (intravenous catheter) were replaced by an indirect method of diagnosis: Doppler Ultrasound. This technique does not measure portal pressure, but indirectly allows the diagnosis of PH. Average speed of portal flow decrease (<10 cm/s) and hepatofugal flow have been reported in cirrhotic dogs with PH. Currently, the focus of the ultrasound is the detection of acquired collateral portal circulation (ACPC), closely correlated with hepatic encephalopathy. The characterization of these vessels is essential to differentiate them from congenital shunts. They are usually multiple vessels, small and tortuous, with turbulent flow, near to the kidneys, and/or a single and larger vessel, draining into the left renal vein (dilated gonadal vein). Gastric, esophageal and mesenteric varices may occur. After identifying the PH, it is important to determine its origin in order to treat the underlying disease. B-Mode Ultrasound and Doppler are the best choices in cases of suspected PH, because they may recognize not just the hypertension, but also its complications and origin.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A kinetic study of the ultrasound-stimulated and acid-catalyzed sonohydrolysis of tetraethyl orthosilicate (TEOS) in solventless TEOS-water heterogeneous mixtures was carried out by means of a calorimetric method as a function of the ultrasound power. The hydrolysis reaction starts in acidulated heterogeneous water-TEOS mixtures after an induction period under ultrasonic stimulation. The ultrasound power seems to play a role on the dynamical coupling of the system originating a continuum upward shifting of the base line during the induction period of sonication. The rate in which the base line is upward shifted diminishes with the power. The best coupling between the ultrasound and the reactant heterogeneous mixtures for this experimental setup was found to occur at 50 W, for which the gelation time was found to be a minimum. The kinetics of the heterogeneous TEOS sonohydrolysis was studied on the basis of a dissolution and reaction modeling. The heterogeneous reaction pathway as deduced from the kinetic study was drawn in a ternary diagram as a function of the ultrasound power. (C) 2006 Elsevier B.V. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Twenty eight Mediterranean buffaloes bulls were scanned with real-time ultrasound (RTU), slaughtered, and fabricated into retail cuts to determine the potential for ultrasound measures to predict carcass retail yield. Ultrasound measures of fat thickness, ribeye area and rump fat thickness were recorded three to five days prior to slaughter. Carcass measurements were taken, and one side of each carcass was fabricated into retail cuts. Stepwise regression analysis was used to compare possible models for prediction of either kilograms or percent retail product from carcass mesaurements and ultrasound measures. Results indicate that possible prediction models for percent or kilograms of retail products using RTU measures were similar in their predictive power and accuracy when compared to models derived from carcass measurements. Both fat thickness and ribeye area were over-predicted when measured ultrasonically compared to measurements taken on the carcass in the cooler. The mean absolute differences for both traits are larger than the mean differences, indicating that some images were interpreted to be larger and some smaller than actual carcass measurements. Ultrasound measurements of REA and FT had positive correlations with carcass measures of the same traits (r=.96 for REA and r=.99 for FT). Standard errors of prediction currently are being used as the standard to certify ultrasound technicians for accuracy. Regression equations using live weight (LW), rib eye area (REAU) and subcutaneous fat thickness (FTU) between 12(th) and 13 (th) ribs and also over the biceps femoris muscle (FTP8) by ultrasound explained 95% of the variation in the hot carcass weight when measure immediately before slaughter.

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Temporal and spatial acoustic intensity (SATA) of therapeutic ultrasound (US) equipment should be monitored periodically. In order to evaluate the conditions of US equipment in use in the city of Piracicaba-Sao Paulo, Brazil, 31 machines - representing all Brazilian manufacturers - were analysed under continuous and pulsed conditions at a frequency of 1 MHz. Data about temporal and spatial acoustic intensity were collected and the use of equipment was surveyed. Intensities of 0.1, 0.2, 0.5, 0.8, 1.0, 1.5, 2.0, 2.5 and 3.0 Wcm -2, indicated on the equipment panel were analysed using a previously calibrated digital radiation pressure scale, model UPM-DT-1 (Ohmic Instruments Co). The acoustic intensity (I) results were expressed as superior and inferior quartile ranges for transducers with metal surfaces of 9 cm 2 and an effective radiation area (ERA) Of 4 cm 2. The results under continuous conditions were: I 0.1 = -20.0% and -96%. I 0.2 = -3.1% and -83.7%. I 0.5 = -35.0% and -86.5%. I 0.8 = -37.5% and -71.0%. I 2.5 = -49.0% and -69.5%. I 3.0 = -58.1% and -77.6%. For pulsed conditions, intensities were: I 0.1 = -40.0% and -86.2%. I 1.0 = -50.0% and -86.5%. I 1.5 = -62.5% and -82.5%. I 2.0 = -62.5% and -81.6%. I 2.5 = -64.7% and -88.8%. I 3.0 = -87.1% and -94.8%. In reply to the questionnaire drawn up to check the conditions of use of equipment, all users reported the use of hydrosoluble gel as a coupling medium and none had carried out previous calibrations. Most users used intensities in the range of 0.4. to 1.0 Wcm -2 and used machines for 300 to 400 minutes per week. The majority of machines had been bought during the previous seven years and weekly use ranged from less than 100 minutes to 700 minutes (11 hours 40 minutes). Findings confirm previous observations of discrepancy between the intensity indicated on the equipment panel and that emitted by the transducer and highlight the necessity for periodic evaluations of US equipment.

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The aim of this study was to evaluate the shape of dental cavities made with the CVDentus® system using different ultrasound power levels. One standard cavity was made on the buccal aspect of 15 bovine incisors with a CVDentus® cylindrical bur (82142). The sample was divided into three groups: G1 - ultrasound with power II; G2 - ultrasound with power III; and G3 - ultrasound with power IV. A standardizing device was used to obtain standardized preparations and ultrasound was applied during one minute in each dental preparation. The cavities were sectioned in the middle, allowing observation of the cavity's profile with a magnifying glass, and width and depth measurement using the Leica Qwin program. The Kruskal-Wallis (p < 0.05) and Dunn statistical analyses demonstrated differences between the dental cavity shapes when powers III and IV were used. However, the cavities that were made with power III presented dimensions similar to those of the bur used for preparation. We concluded that the power recommended by the manufacturer (III) is the most adequate for use with the CVDentus® system.