Gradient Descending
Mostrando 1-12 de 26 artigos, teses e dissertações.
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1. 3D image registration of the human brain / Registro de imagens 3D do cerebro humano
Image Registration is the process that aligns two or more images in a common reference system of spacial coordinates [31]. It is an important problem with several applications in Medical Imaging, enabling, for instance, the analysis of changes in anatomy along time by the registration of images from the same modality, and the study of combined anatomic and p
Publicado em: 2009
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2. Estudo tomográfico de pressões de colapso alveolar e níveis isogravitacionais em pulmões de pacientes com SDRA e LPA / Tomographic study of alveolar collapsing pressures and isogravitational levels and in the lungs of patients with ARDS and/or ALI
A prospective clinical study performed on 11 patients with ARDS or ALI with the intention of studying the regional behavior of lung tissue density and alveolar collapse along the three spatial axes. An initial recruitment maneuver was followed by multiple semi-complete CT scans at descending levels of PEEP. Multiple linear regression (R2=0.83) showed a gravi
Publicado em: 2009
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3. Coarctation of the aorta with right aortic arch. A rare case and atypical clinical picture.
We report the case of a 13-year-old girl with a diffusely hypoplastic right aortic arch, anomalous origin of the left subclavian artery, and a small, insignificant ventricular septal defect. The patient's pulse was forceful at the carotid arteries, but it was markedly weaker at all extremities. Catheterization revealed that both common carotid arteries arose
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4. Use of continuous wave Doppler ultrasound velocimetry to assess the severity of coarctation of the aorta by measurement of aortic flow velocities.
Peak ascending and descending aortic blood flow velocities were measured using continuous wave Doppler ultrasound velocimetry in 30 children with coarctation or recoarctation of the aorta and in 13 control subjects. The results were compared with the arm to leg systolic blood pressure difference. The peak flow velocities in the descending aorta were signific
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5. Requirement of aquaporin-1 for NaCl-driven water transport across descending vasa recta
Deletion of AQP1 in mice results in diminished urinary concentrating ability, possibly related to reduced NaCl- and urea gradient–driven water transport across the outer medullary descending vasa recta (OMDVR). To quantify the role of AQP1 in OMDVR water transport, we measured osmotically driven water permeability in vitro in microperfused OMDVR from wild-
American Society for Clinical Investigation.
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6. Continuous wave Doppler echocardiography and coarctation of the aorta: gradients and flow patterns in the assessment of severity.
Indices of the severity of coarctation derived from non-invasive Doppler echocardiography were compared with measurements derived from cardiac catheterisation and angiography. In 24 Doppler studies from 17 children instantaneous peak systolic and diastolic gradients and time to half peak systolic and diastolic velocities were compared with the ratio of the c
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7. Evaluation of aortic coarctation after surgical repair: role of magnetic resonance imaging and Doppler ultrasound.
OBJECTIVE--To compare the usefulness of magnetic resonance imaging (MRI) and Doppler ultrasound with that of cross sectional echocardiography and oscillometric blood pressure measurement for the evaluation of aortic coarctation after surgical repair. DESIGN--Prospective study. Aortic diameters measured by cross sectional echocardiography, MRI, and angiograph
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8. Functional significance of coronary collateral circulation during dynamic exercise evaluated by thallium-201 myocardial scintigraphy.
Sixty-five patients with angiographically documented coronary artery disease were investigated by thallium-201 (201Tl) scintigraphy to determine the role of the collateral circulation during dynamic exercise. Fifty-three patients had complete proximal occlusion of at least one major coronary artery. One patient had total occlusion of all three major coronary
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9. Exercise haemodynamics of coarctation of the aorta: Acute effects of propranold1
Eight patients with aortic coarctation were studied at rest and during supine bicycle exercise before and after intravenous propranolol 0·17 mg./kg. The mean pressure gradient across the aortic narrowing increased from 16 to 45 mm. Hg during exercise, and was reduced to 11 and 31 mm. Hg after propranolol. Total peripheral resistance was increased by propran
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10. Case Study of the Distribution of Mucosa-Associated Bifidobacterium Species, Lactobacillus Species, and Other Lactic Acid Bacteria in the Human Colon
The distribution of mucosa-associated bacteria, bifidobacteria and lactobacilli and closely related lactic acid bacteria, in biopsy samples from the ascending, transverse, and descending parts of the colon from four individuals was investigated by denaturing gradient gel electrophoresis (DGGE). Bifidobacterial genus-specific, Lactobacillus group-specific, an
American Society for Microbiology.
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11. Evidence for a concentration gradient favoring outward movement of sodium from the thin loop of Henle.
Recent models of the urinary concentrating mechanism have postulated that urea in the medullary interstitium creates a transtubular concentration gradient for sodium between fluid at the end of the descending limb of Henle's loop and the medullary interstitium, favoring the passive outward movement of sodium from Henle's thin ascending limb. These experiment
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12. Regional distribution and alterations of lectin binding to colorectal mucin in mucosal biopsies from controls and subjects with inflammatory bowel diseases.
Glycoconjugate composition of colorectal goblet cell mucin was characterized according to the anatomical distribution of lectin-binding sites in mucosal biopsies from 35 control subjects and 55 patients with inflammatory bowel disease. 24 of the controls had mucosal inflammation on biopsy, without clinical evidence of inflammatory bowel disease. These inflam