211,224 research outputs found
Cittadinanza e idea di responsabilità
No full textL'idea di cittadinanza ha bisogno di essere alimentata da una forte tensione etica e da un diffuso senso della democrazi
Evaluation of retinal nerve fiber layer with optic nerve tracking optical coherence tomography in thyroid-associated orbitopathy.
No full textAbstract
AIMS:
To evaluate retinal nerve fiber layer (RNFL) thickness in eyes with Graves' orbitopathy (GO), in eyes with ocular hypertension (OHT) and in a control group of healthy eyes.
METHODS:
Observational, controlled cross-sectional study. We evaluated all patients with primary open-angle glaucoma (POAG) and all patients with GO and intraocular pressure >23 mm Hg in primary position examined from March 2006 to June 2007. Forty apparently healthy patients (80 eyes) were enrolled as a control group. Complete ophthalmic evaluation, visual field (VF) examination with the Humphrey Visual Field Analyzer and RNFL thickness measurement with optic nerve tracking optical coherence tomography (ONT-OCT; OCT/SLO, OTI, Toronto, Ont., Canada) were performed.
RESULTS:
Among 116 eyes with POAG [58 patients, 32 males, 26 females, mean age 62 (46-71) years], RNFL was reduced in 87 eyes (75%, p = 0.05) when compared with the control group, and a good correlation was found between RNFL thickness and VF abnormalities (Spearman's rho 0.822; p = 0.001). Among 60 eyes [30 patients, 12 males, 18 females, mean age 56 (50-69) years] with GO and OHT, nonglaucomatous diffuse abnormalities of the VF were detected in 44 eyes (73.3%, p = 0.03), while RNFL thinning was present in 14 eyes (9 patients, 23.3%, p = 0.03). No correlation was found between RNFL thickness and VF abnormalities (Spearman's rho 0.365; p = 0.02). No significant differences in RNFL pattern were present between the group with GO, OHT and RNFL thinning and the group with POAG.
CONCLUSIONS:
In patients with GO and OHT, evaluation of RNFL thickness with ONT-OCT may represent an objective diagnostic technique for detecting optic neuropathy
The ReZoom multifocal intraocular lens: 2-year follow-up.
No full textAbstract
PURPOSE:
To evaluate distance, intermediate, and near visual acuity and patient satisfaction over a period of 2 years after implantation of the ReZoom multifocal intraocular lens.
METHODS:
Fifty-five eyes of 35 cataract patients were included in this retrospective study. Only patients with a preoperative photopic pupillary diameter superior to 3 mm were included. Monocular visual acuities and visual symptoms were compared at different time points.
RESULTS:
Preoperative mean distance uncorrected visual acuity (UCVA) was 0.5+/-0.3 LogMAR, uncorrected intermediate visual acuity (UCiVA) at 50 cm was 0.6+/-0.3 LogMAR, and near uncorrected visual acuity (UNVA) was J7.8+/-0.6. Mean follow-up was 28.1+/-7.2 months. At 6 months, UCVA improved to 0.05+/-0.09 logMAR (p<0.001), UCiVA to 0.08+/-0.1 LogMAR (p<0.001), and UNVA to J2.4+/-0.4 (p<0.001). At 24 months, UCVA was 0.04+/-0.08 LogMAR, UCiVA was 0.07+/-0.1 LogMAR, and UNVA was J2.3+/-0.7. No significant differences were observed between the values at 6 months versus 24 months. At the 3-month visit, moderate glare and halo were reported by 10% and 13% of patients, respectively. The occurrence of visual symptoms decreased with time, with only 7% and 5% of patients reporting moderate glare and halo at the last visit, respectively.
CONCLUSIONS:
The ReZoom lens provides quality vision at all distances. Between 6 and 24 months of follow-up, a further improvement of optical disturbances rather than uncorrected visual acuity may be expected
Simulation of the Vibratory Behavior of Slender Shafts Subject to Transverse Loads Moving in the Axial Direction
No full textIn various machines of the manufacturing industry, and in particular in paper converting machinery, there are shafts operating under conditions similar to that of a slender beam subjected to a transverse load moving in the axial direction. This condition can lead to vibrations and consequent deterioration of the machine performance and of the product quality. The problem has been theoretically studied in the literature since the 1990s. While shaft mass and stiffness are universally considered among the most influential parameters on its vibratory behavior, less obvious and not investigated in the literature is the influence of the spatial interval between two successive loads, an aspect that should be considered in the shaft design phase. In fact, if that is less than the length of the shaft, i.e., if there is more than one transverse load on the shaft at a given time, the vibration level may decrease with respect to the single-load configuration. This work describes the development of a mathematical model of a slender shaft hinged at its ends, representing the rotor of a paper roll perforating unit, with the SW Mathematica. The effect of a load moving axially at a given speed followed by similar loads after given spatial intervals was simulated investigating the influence of speed and load interval on shaft vibrations and resonance. The results showed how reducing the load interval can lead to a reduction of the shaft vibration which is a useful indication on possible design corrective actions
Applicazione di un codice FEM per la determinazione delle caratteristiche del cuscino a pattini oscillanti
No full textCaratterizzazione teorica e sperimentale di cuscini radiali idrodinamici a pattini oscillanti
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