974 resultados para Electron-Cyclotron Resonance


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A new species of a trichurid nematode Trichuris travassosi n. sp., recovered from a wild rodent in the State of Rio Grande do Sul, Brazil, is described and compared to T. myocastoris (Enigk, 1933) and their differentiation was on the basis of detailed morphometrical study. Oryzomys nigripes (Olfers, 1818) is a new host record for the genus. The denomination spicular prepuce is proposed to designate the structure previously named spicular sheath and, conversely, spicular sheath to indicate the cuticle that convers the spicule.

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Balanorchis anastrophus Fischoeder, 1901 from the reticulum from Bos taurus is reported for the first time in State of Pará, Brazil. The surface topography as revealed by scanning electron microscopy is presented.

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Bicotylophora trachinoti (Mac Callum, 1921) from Trachinotus carolinus L.; Pseudanthocotyloides heterocotyle (Van Beneden, 1871) from Cetengraulis edentulus (Cuvier), and Decapterus punctatus (Cuvier), new host records; Pseudomazocraes selene Hargis, 1957 from Selene vomer (L.) and Caranx latus Agassiz, new host record, are reported for the first time in Brazil from the coast of Rio de Janeiro State. The marine fishes Diplectrum sp. and Pomatomus saltatrix (L.) are respectively new host records for Pseudotagia cupida (Hargis, 1956) and Macrovalvitrema sinaloense Caballero & Bravo Hollis, 1955. Measurements, original figures and photos in scanning electron microscopy of B. trachinoti are presented. The egg with filaments is reffered for the first time in the genus Pseudanthocotyloides.

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Coronary magnetic resonance angiography (MRA) is a technique aimed at establishing a noninvasive test for the assessment of significant coronary stenoses. There are certain boundary conditions that have hampered the clinical success of coronary MRA and coronary vessel wall imaging. Recent advances in hardware and software allow for consistent visualization of the proximal and mid portions of the native coronary arteries. Current research focuses on the use of intravascular MR contrast agents and black blood coronary angiography. One common goal is to create a noninvasive test which might allow for screening for major proximal and mid coronary artery disease. These novel approaches will represent a major step forward in diagnostic cardiology.

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BACKGROUND: According to recent guidelines, patients with coronary artery disease (CAD) should undergo revascularization if significant myocardial ischemia is present. Both, cardiovascular magnetic resonance (CMR) and fractional flow reserve (FFR) allow for a reliable ischemia assessment and in combination with anatomical information provided by invasive coronary angiography (CXA), such a work-up sets the basis for a decision to revascularize or not. The cost-effectiveness ratio of these two strategies is compared. METHODS: Strategy 1) CMR to assess ischemia followed by CXA in ischemia-positive patients (CMR + CXA), Strategy 2) CXA followed by FFR in angiographically positive stenoses (CXA + FFR). The costs, evaluated from the third party payer perspective in Switzerland, Germany, the United Kingdom (UK), and the United States (US), included public prices of the different outpatient procedures and costs induced by procedural complications and by diagnostic errors. The effectiveness criterion was the correct identification of hemodynamically significant coronary lesion(s) (= significant CAD) complemented by full anatomical information. Test performances were derived from the published literature. Cost-effectiveness ratios for both strategies were compared for hypothetical cohorts with different pretest likelihood of significant CAD. RESULTS: CMR + CXA and CXA + FFR were equally cost-effective at a pretest likelihood of CAD of 62% in Switzerland, 65% in Germany, 83% in the UK, and 82% in the US with costs of CHF 5'794, euro 1'517, £ 2'680, and $ 2'179 per patient correctly diagnosed. Below these thresholds, CMR + CXA showed lower costs per patient correctly diagnosed than CXA + FFR. CONCLUSIONS: The CMR + CXA strategy is more cost-effective than CXA + FFR below a CAD prevalence of 62%, 65%, 83%, and 82% for the Swiss, the German, the UK, and the US health care systems, respectively. These findings may help to optimize resource utilization in the diagnosis of CAD.

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This prospective study compares repetitive thick-slab single-shot projection magnetic resonance cholangiopancreatography (MRCP) with endoscopic ultrasonography (EUS) for the detection of choledocholithiasis. Fifty-seven consecutive patients (36 women, mean age 61) referred for suspected choledocholithiasis underwent MRCP, followed by EUS. Each procedure was performed by different operators blinded to the results of the other investigation. MR technique included a turbo spin-echo T2-weighted axial sequence with selective fat saturation (SPIR/TSE, TE=70 ms, TR=1,600 ms), followed by coronal dynamic MRCP. The same thick-slab slice was sequentially acquired 12 times as breath-hold single-shot projection imaging (SSh, TE=900 ms, TE=8,000 ms) centred on the common bile duct (CBD). Two experienced radiologists independently and blindly evaluated MR images for the detection of CBD stones. Their inter-observer agreement kappa was determined. Secondly, the two observers read MR images in consensus again. CBD stones were demonstrated in 18 out of 57 patients (31.6 %) and confirmed by endoscopic retrograde cholangiography (ERCP, n=17) or intraoperative cholangiography (n=1). Clinical follow-up served as the "gold standard" in patients with negative results without following invasive procedure (n=28). Sensitivity, specificity, accuracy, positive and negative predictive value for MRCP resulting from consensus reading were 94.9%, 94.4%, 94.7%, 97.4% and 89.5%, respectively. Corresponding values of EUS were 97.4%, 94.4%, 96.5%, 97.4% and 94.4%. Inter-observer agreement kappa was 0.81. Repetitive thick-slab single-shot projection MRCP is an accurate non-invasive imaging modality for suspected choledocholithiasis and should be increasingly used to select those patients who require a subsequent therapeutic procedure, namely ERCP.

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The eggs of Anopheles cruzii and An. bellator are described and illustrated using scanning electron micrographs. Hatching was observed, and larval exit documented. No morphological differences were found between the eggs of the two species.

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PURPOSE: To assess the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography of the wrist with regard to joint space width and amount of contrast material between the opposing cartilage surfaces. MATERIALS AND METHODS: Fifteen consecutive patients (12 male, mean age 38.1 years) were included in this Institutional Review Board-approved prospective study. Three-compartment wrist MR arthrographies were performed between October and December 2009 on a 3 T unit using a fat-suppressed T1-weighted isotropic high-resolution volumetric interpolated breathhold examination (VIBE) sequence in the coronal plane, with and without axial traction (3 kg). Two radiologists measured radiocarpal (radioscaphoid, radiolunate) and midcarpal (lunocapitate, hamatolunate) joint space widths, with and without traction, and assessed the amount of contrast material between the opposing cartilage surfaces using a three-point scale: 0 = absence, 1 = partial, 2 = complete. RESULTS: With traction, joint space width increased significantly at the radioscaphoid (Delta = 0.78 mm, P < 0.01), radiolunate (Delta = 0.18 mm, P < 0.01), and lunocapitate (Delta = 0.45 mm, P < 0.01) spaces, and both observers detected significantly more contrast material between the cartilage surfaces. At the hamatolunate space, the differences in joint space width (Delta = 0.14 mm, P = 0.54) and amount of contrast material were not significant. CONCLUSION: Direct wrist MR arthrography with axial traction of 3 kg increases joint space width at the radiocarpal and lunocapitate spaces, and prompts better coverage of the articular cartilage by the contrast material. J. Magn. Reson. Imaging 2011;. (c) 2011 Wiley-Liss, Inc.

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In correlative microscopy, light microscopy provides the overview and orientation of the complex cells and tissue, while electron microscopy offers the detailed localization and correlation of subcellular structures. In this chapter we offer detailed high-quality electron microscopical preparation methods for optimum preservation of the cellular ultrastructure. From such preparations serial thin sections are collected and used for comparative histochemical, immunofluorescence, and immunogold staining.In light microscopy histological stains identify the orientation of the sample and immunofluorescence labeling facilitates to find the region of interest, namely, the labeled cells expressing the macromolecule under investigation. Sections, labeled with immunogold are analyzed by electron microscopy in order to identify the label within the cellular architecture at high resolution.

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Image quality in magnetic resonance imaging (MRI) is considerably affected by motion. Therefore, motion is one of the most common sources of artifacts in contemporary cardiovascular MRI. Such artifacts in turn may easily lead to misinterpretations in the images and a subsequent loss in diagnostic quality. Hence, there is considerable research interest in strategies that help to overcome these limitations at minimal cost in time, spatial resolution, temporal resolution, and signal-to-noise ratio. This review summarizes and discusses the three principal sources of motion: the beating heart, the breathing lungs, and bulk patient movement. This is followed by a comprehensive overview of commonly used compensation strategies for these different types of motion. Finally, a summary and an outlook are provided.