81 resultados para grating acuity


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This work presents a method to obtain B-scan images based on linear array scanning and 2R-SAFT. Using this technique some advantages are obtained: the ultrasonic system is very simple; it avoids the grating lobes formation, characteristic in conventional SAFT; and subaperture size and focussing lens (to compensate emission-reception) can be adapted dynamically to every image point. The proposed method has been experimentally tested in the inspection of CFRP samples. © 2010 American Institute of Physics.

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Photoluminescence and photo-excited conductivity data as well as structural analysis are presented for sol-gel SnO2 thin films doped with rare earth ions Eu3+ and Er3+, deposited by sol-gel-dip-coating technique. Photoluminescence spectra are obtained under excitation with various types of monochromatic light sources, such as Kr+, Ar+ and Nd:YAG lasers, besides a Xe lamp plus a selective monochromator with UV grating. The luminescence fine structure is rather different depending on the location of the rare-earth doping, at lattice symmetric sites or segregated at the asymmetric grain boundary layer sites. The decay of photo-excited conductivity also shows different trapping rate depending on the rare-earth concentration. For Er-doped films, above the saturation limit, the evaluated capture energy is higher than for films with concentration below the limit, in good agreement with the different behaviour obtained from luminescence data. For Eu-doped films, the difference in the capture energy is not so evident in these materials with nanoscocopic crystallites, even though the luminescence spectra are rather distinct. It seems that grain boundary scattering plays a major role in Eu-doped SnO2 films. Structural evaluation helps to interpret the electro-optical data. © 2010 IOP Publishing Ltd.

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Purpose: To report the surgical technique and outcomes of a no-ring approach to posterior chamber intraocular lens (IOL) implantation in children and young adults with subluxation of the crystalline lens. Methods: A three-piece 5.5-mm hydrophobic acrylic IOL was implanted in which the optic and one haptic were inside the capsular bag and the other haptic was in the ciliary sulcus. The implantations were done in 13 eyes of 10 patients with lens subluxation. One haptic was fixated in the ciliary sulcus by passing it through an operculum-shaped opening in the capsular bag edge, made between 2 and 3 clock hours, clockwise from the middle point of the subluxated area. Results: The mean age of the 10 patients was 12.61 ± 8.04 years and the mean follow-up was 21.38 ± 11.29 months. The mean preoperative and postoperative best-corrected visual acuity (BCVA) was 1.15 ± 0.58 and 0.37 ± 0.17 logarithm of the minimum angle of resolution, respectively, in 11 measured eyes. The postoperative BCVA was 20/40 or better in 4 eyes (36.36%), between 20/40 and 20/60 in 6 eyes (54.54%), and between 20/80 and 20/100 in 1 eye (9.09%). The BCVA improved in all eyes. Postoperative IOL decentration between 1.0 and 1.5 mm occurred in 3 of 13 eyes (23.08%). Conclusion: The results indicate that the no-ring technique allows centration of an IOL implanted into a subluxated capsular bag without using capsule tension rings. © SLACK Incorporated.

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Purpose: To assess the safety and efficacy of transitioning patients whose intraocular pressure (IOP) had been insufficiently controlled on prostaglandin analog (PGA) monotherapy to treatment with travoprost 0.004%/timolol 0.5% fixed combination with benzalkonium chloride (TTFC). Methods: This prospective, multicenter, open-label, historical controlled, single-arm study transitioned patients who had primary open-angle glaucoma, pigment dispersion glaucoma, or ocular hypertension and who required further IOP reduction from PGA monotherapy to oncedaily treatment with TTFC for 12 weeks. IOP and safety (adverse events, corrected distance visual acuity, and slit-lamp biomicroscopy) were assessed at baseline, week 4, and week 12. A solicited ocular symptom survey was administered at baseline and at week 12. Patients and investigators reported their medication preference at week 12. Results: Of 65 patients enrolled, 43 had received prior travoprost therapy and 22 had received prior nontravoprost therapy (n = 18, bimatoprost; n = 4, latanoprost). In the total population, mean IOP was significantly reduced from baseline (P = 0.000009), showing a 16.8% reduction after 12 weeks of TTFC therapy. In the study subgroups, mean IOP was significantly reduced from baseline to week 12 (P = 0.0001) in the prior travoprost cohort (19.0% reduction) and in the prior nontravoprost cohort (13.1% reduction). Seven mild, ocular, treatment-related adverse events were reported. Of the ten ocular symptom questions, eight had numerically lower percentages with TTFC compared with prior PGA monotherapy and two had numerically higher percentages with TTFC (dry eye symptoms and ocular stinging/burning). At week 12, TTFC was preferred over prior therapy for 84.2% of patients (48 of 57) by the patients themselves, and for 94.7% of patients (54 of 57) by their physicians. Conclusion: When TTFC replaced PGA monotherapy in patients whose IOP had been uncontrolled, the outcome was a significant reduction in IOP and an acceptable safety and tolerability profile. Most patients and investigators preferred TTFC to prior PGA monotherapy. © 2012 Costa et al, publisher and licensee Dove Medical Press Ltd.

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Background: Orbital infection is an uncommon devastating infection and is usually a complication of paranasal sinus infection. Without appropriate treatment, orbital infection may lead to serious complications, even death. Prompt treatment is mandatory to avoid visual loss or intracranial complications. The literature shows that initially, intravenous antibiotics should be administered, and after 48 h, if no improvement appears, the affected orbit and the sinuses must be surgically drained. The authors describe two cases of orbital cellulitis with a brief literature review. Case report: The authors describe two cases of orbital abscess caused by paranasal sinus infection. In case 1, the patient presented a decreased visual acuity associated with ophthalmoplegia of the right eye. In case 2, the patient presented a decreased visual acuity. Thus, administration of intravenous antibiotic combined with surgical drainage was performed. After surgical procedure, eye movements were normalized in case 1, and in both patients, the visual acuity returned to normal parameters. Discussion: The authors recommend early surgical drainage with parenteral antibiotic administration and careful postoperative observations by monitoring the signs and symptoms of the orbital complaint. © 2012 Springer-Verlag.

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The leaf spot (Mycosphaerella leaf disease = MLD) caused by Teratosphaeria nubilosa has caused damage in eucalypt plantations in southern and southeastern Brazil. The need to assess the disease in the field to evaluate of this damage, efficiency control, evaluation of germplasm induces to the necessity of having a visual scale for evaluation of disease. The objective was to develop a diagrammatic scale for young leaves and one for adult leaves of Eucalyptus globules for MLD. To do so, the leaves collected in the field were scanned for image analysis. The damaged area, the healthy leaf area and the external area of the same scale RGB (Red, Green, Blue) were determined. Subsequently, it was determinate the levels of severity depending on the sample distribution with seven levels for young leaves and six for adult leaves. For the visual acuity test and validate the scale, the leaves were evaluated for severity, with and without scale. With this proposed scales, the assessors showed good accuracy both for young and adult leaves with R2=0,98 and R2=0,80, respectively. The importance of the development of diagrammatic scales for assessing MLD in eucalyptus must to the fact that allows quantification of the symptoms accurately and precisely.

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Several Lamb wave modes can be coupled to a particular structure, depending on its geometry and transducer used to generate the guided waves. Each Lamb mode interacts in a particular form with different types of defects, like notches, delamination, surface defects, resulting in different information which can be used to improve damage detection and characterization. An image compounding technique that uses the information obtained from different propagation modes of Lamb waves for non-destructive testing of plate-like structures is proposed. A linear array consisting of 16 piezoelectric elements is attached to a 1 mm thickness aluminum plate, coupling the fundamental A0 and S0 modes at the frequencies of 100 kHz and 360 kHz, respectively. For each mode two images are obtained from amplitude and phase information: one image using the Total Focusing Method (TFM) and one phase image obtained from the Sign Coherence Factor (SCF). Each TFM image is multiplied by the SCF image of the respective mode to improve contrast and reduce side and grating lobes effects. The high dispersive characteristic of the A0 mode is compensated for adequate defect detection. The information in the SCF images is used to select one of the TFM mode images, at each pixel, to obtain the compounded image. As a result, dead zone is reduced, resolution and contrast are improved, enhancing damage detection when compared to the use of only one mode. © 2013 Elsevier Ltd.

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Purpose: To observe the frequency of the occurrence of the anophthalmic socket in the Middle West region of the state of São Paulo and to describe the demographic profile of the carriers in a population-based data. Methods: A cross-sectional study involve a random sampling carried out in twelve cities of the Middle West region of the state of São Paulo, for which the reference center is the city of Botucatu was done. The participators were chosen by assortment which considered the houses of these people. It was established a sampling with 11,453 people. All the exams were realized using a Mobile Ophthalmologic Unit. The research protocol included the demographic data and the complete ophthalmologic exam (anamnesis, ocular and systemic antecedents, familiar antecedents, visual acuity with and without correction, tonometry, biomicroscopy, fundoscopy, and refraction exam). All the data were transferred to an Excel spreadsheet and submitted to a descriptive analysis and were presented by the frequency of the occurrence. Results: Ophthalmic socket frequency in the Middle West region of the state of São Paulo was 0.96%. We found 11 cases of anophthalmic socket, with involvement of 0.7 % in females and 1.3 %, male. The most common causes of anophthalmic socket were glaucoma (blind painful eye), microphthalmia, trauma, and endophthalmitis. The majority of the people were 40 years old or more, and we found just one person younger than 19 years old. Conclusion: The anophthalmic socket occurred in 0.96% of the habitants of the Middle West region of São Paulo State, occurring mainly in male and with large variety of the affected ages.

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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Comunicação - FAAC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Educação - FCT