322,954 research outputs found
Valore del wash-out in confronto alle altre metodiche radiologiche nel diagnostico della ipertensione nefrovascolare e renale
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Contrast-enhanced three dimensional (3D) MR angiography (CEMRA) of neck vessels: does dephasing effect alter diagnostic accuracy?
No full textThe aim of this study was to evaluate diagnostic accuracy of contrast-enhanced MRA (CEMRA) compared with digital subtraction angiography (DSA) in studying neck vessels of 48 patients. In three groups of patients, we used three MRA protocols differing for voxel size to assess if intravoxel dephasing effects could modify accuracy of CEMRA. Accuracy and correlation with DSA results were calculated in all patients and separately in the three groups. A qualitative analysis of the likeness between morphology of the stenosis in CEMRA and DSA images was also assessed. In all patients accuracy and agreement with DSA were 96% and k=0.85 in subclavian arteries, 96% and k=0.84 in vertebral artery, 97% and k=0.88 in common carotid arteries, and 94% and k=0.86 in internal carotid arteries. In the three groups accuracy and agreement with DSA did not show any significant difference. Qualitative analysis of CEMRA and DSA images revealed a better agreement in depicting the morphology of stenosis using a smaller voxel size. The CEMRA represents a powerful tool for the non-invasive evaluation of neck vessels. Overestimation trend of CEMRA is confirmed and the reduction of voxel size, decreasing the dephasing intravoxel effect, allows to have a better overlapping of stenosis morphology on CEMRA compared with DSA, but it does not yield diagnostic gain in the stenosis grading
[Early diagnosis of rapidly progressive glomerulonephritis]
No full textThe term rapidly progressive glomerulonephritis (RPGN) designates a group of glomerular diseases with different pathogenetic and clinical features, rapidly leading to renal or patient death in about 90% of the untreated cases. Histopathologically, it is characterized by glomerular crescents in at least 50-75% of the glomeruli (necrotizing crescentic glomerulonephritis), and very often, glomerular necrosis. The situation is, however, potentially reversible if adequately treated, and a favourable outcome depends largely on early diagnosis and treatment. Early diagnosis can be achieved if due importance is given to even seemingly unspecific manifestations such as "flu like syndrome" associated with "glomerular" hematuria. These manifestations are detectable before the down-hill course of renal functional derangement becomes evident and should lead the physician to consider RPGN among the diagnostic possibilities. Final diagnosis rests on serological tests and kidney biopsy. The battery of diagnostic serological tests (anti-GBM, anti-DNA antibodies, cryoglobulins, etc.) has recently been enriched by the assay of anti-neutrophil cytoplasmic antibodies (ANCA). These antibodies are detectable in over 90% of cases of Wegener's granulomatosis and primary necrotizing crescentic glomerulonephritis with or without lung involvement. ANCA-associated glomerulonephritis is the commonest form of RPGN, and the new serological assay provides an important tool for its early recognition. Renal biopsy is necessary to evaluate the severity of the nephritic process and modulate treatment accordingly. Timely diagnosis is one of the most important factors contributing to successful treatment outcome over both the short and the long term
Transient reduction of regional myocardial perfusion during angina at rest with S-T segment depression or normalization of negative T-waves
No full textAverage magnitude of heartbeat fluctuactions in healthy subjects after exposure to 4 hours head down bed rest.
No full textKinetic Combustion Neural Modelling Integrated into Computational Fluid Dynamics
No full textA methodology has been developed to replace traditional chemical kinetics model calculation with Neural Models and applied to air-methane combustion. The reacting flow field has been described taking a detailed chemistry reaction mechanism into account. Convective and turbulent diffusive transport of species have been taken into consideration by means of a well known finite volume CFD code. Two version of such a mechanism have been developed. The first one is based on traditional differential equations representing the specie production rates. Such equations are integrated over the time intervals related to the cell volumes and local volumetric flows.A reduced combustion mechanism involving twenty species and sixty-eight reactions has been developed both for traditional calculation as well as for the Neural Model ones. At the real end combustion flow fields are calculated with kinetics Neural Models with a CPU time forty-two times smaller than that of traditional procedures with a comparable solution accuracy of the combustion flow fields
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cardiovascular reactivity to physical and psychologic stress during long-term treatment with nitrendipine in essential hypertension.
No full textNitrendipine is a second-generation dihydropyridine calcium antagonist selective for hypertension. The aim of this study was to assess whether, in addition to reduce resting blood pressure, nitrendipine also affects the cardiovascular reactivity to physical and psychologic stress. Ten essential hypertensive patients, out of treatment for at least 2 weeks, underwent a symptom-limited dynamic maximal exercise and a mental arithmetic stress test (MAT) after placebo (1 week) and 1 and 5 weeks of active treatment with nitrendipine (20 mg q.i.d.). To evaluate the cardiovascular response to exercise and its changes during treatment, the slope of the regression line (if statistically significant) of the blood pressure, heart rate, and rate-pressure product (RPP) values against workload were considered, together with exercise capacity, blood pressure, and pressure-rate product at the peak of maximal exercise. During mental stress, indexes of stroke volume (SVI), cardiac output (COI), and peripheral resistance (TPRI) were obtained by Doppler transcutaneous aortovelography (TAV). Resting systolic and diastolic BP were significantly reduced during treatment. The average length of exercise was 7.3, 7.64, and 8.0 min after, respectively, placebo, 1, and 5 weeks of treatment. Peak systolic and diastolic BP, peak RPP, and RPP slope were consistently decreased after treatment, significantly for peak DBP and RPP. During mental arithmetics, a significant increase of BP and HR and a decrease of SVI were observed on placebo; both BP and SVI responses disappeared after 5 weeks on nitrendipine, whereas the HR increase was unchanged. Peak values of COI and TPRI during MAT were significantly increased and decreased, respectively, after nitrendipine, whereas basal values showed similar changes, but not statistically significant
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