78 research outputs found

    Binocular Interactions in Glaucoma Patients With Nonoverlapping Visual Field Defects:Contrast Summation, Rivalry, and Phase Combination

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    PURPOSE. In glaucoma, visual field defects in the left and right eye may be non-overlapping, resulting in an intact binocular visual field. In clinical management, these patients are often considered to have normal vision. However, visual performance also relies on binocular processing. The aim of this study was to evaluate binocular visual functions in glaucoma patients with intact binocular visual field, normal visual acuity, and stereoscopy.METHODS. We measured in 10 glaucoma patients and 12 age-similar controls: (1) monocular and binocular contrast sensitivity functions (CSF) using a modified quick CSF test to assess binocular contrast summation, (2) dominance during rivalry, and (3) contrast ratio at balance point with a binocular phase combination test. A mirror stereoscope was used to combine the left and right eye image (each 10 degrees horizontally by 12 degrees vertically) on a display.RESULTS. Area under the monocular and binocular CSF was lower in glaucoma compared to healthy (P &lt; 0.001), but the binocular contrast summation ratio did not differ (P = 0.30). For rivalry, the percentage of time of mixed percept was 9% versus 18% (P = 0.056), the absolute difference of the percentage of time of dominance between the two eyes 19% versus 10% (P = 0.075), and the rivalry rate 8.2 versus 12.1 switches per minute (P = 0.017) for glaucoma and healthy, respectively. Median contrast ratio at balance point was 0.66 in glaucoma and 1.03 in controls (P = 0.011).CONCLUSIONS. Binocular visual information processing deficits can be found in glaucoma patients with intact binocular visual field, normal visual acuity, and stereoscopy.</p

    Retinal Contrast Gain Control and Temporal Modulation Sensitivity Across the Visual Field in Glaucoma at Photopic and Mesopic Light Conditions

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    PURPOSE. Glaucoma affects many aspects of visual performance, including adaptation, and this may depend on ambient luminance. We determine the influence of glaucoma and luminance on temporal aspects of adaptation, specifically on contrast gain control and temporal modulation sensitivity (TMS). METHODS. This case-control study included 12 glaucoma patients and 25 age-similar controls (50-70 years). Threshold perimetry was performed with a minimized testing grid (fovea and four peripheral locations). Stimuli (Goldmann size III 50 ms increment/decrement) were presented on a time-varying background with sinusoidally-modulated luminance (amplitude 60%; frequency 0-30 Hz; mean background luminance, 1 and 100 cd/m(2)). TMS (2.5-30 Hz) was measured in the same locations with a sinusoidally-modulated stimulus (Goldmann size IV, 334 ms) on a steady background (1 and 100 cd/m(2)). RESULTS. In healthy subjects, contrast sensitivity decreased with increasing background modulation frequency and increased again at very high frequencies, indicating contrast gain control. Minimum sensitivity was located between 2.5 and 20 Hz, depending on luminance and eccentricity. In glaucoma patients, the same frequency dependency was found (P = 0.12) but with an overall reduced sensitivity (P = 1 x 10(-5)), independent of luminance (P = 0.20). Decrements differentiated better between glaucoma and healthy subjects than increments (P = 0.004). TMS was reduced in glaucoma (P = 5 x 10(-6)) across all frequencies and luminance levels, with complete loss for high frequencies at 1 cd/m(2). CONCLUSIONS. Contrast gain control is largely unaffected in glaucoma, suggesting intact amacrine cell function. Perimetry with decrements or a high-frequency stimulus on a low-luminance background seems best to differentiate between glaucoma and healthy subjects

    Binocular Interactions in Glaucoma Patients With Nonoverlapping Visual Field Defects:Contrast Summation, Rivalry, and Phase Combination

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    PURPOSE: In glaucoma, visual field defects in the left and right eye may be non-overlapping, resulting in an intact binocular visual field. In clinical management, these patients are often considered to have normal vision. However, visual performance also relies on binocular processing. The aim of this study was to evaluate binocular visual functions in glaucoma patients with intact binocular visual field, normal visual acuity, and stereoscopy. METHODS: We measured in 10 glaucoma patients and 12 age-similar controls: (1) monocular and binocular contrast sensitivity functions (CSF) using a modified quick CSF test to assess binocular contrast summation, (2) dominance during rivalry, and (3) contrast ratio at balance point with a binocular phase combination test. A mirror stereoscope was used to combine the left and right eye image (each 10° horizontally by 12° vertically) on a display. RESULTS: Area under the monocular and binocular CSF was lower in glaucoma compared to healthy (P < 0.001), but the binocular contrast summation ratio did not differ (P = 0.30). For rivalry, the percentage of time of mixed percept was 9% versus 18% (P = 0.056), the absolute difference of the percentage of time of dominance between the two eyes 19% versus 10% (P = 0.075), and the rivalry rate 8.2 versus 12.1 switches per minute (P = 0.017) for glaucoma and healthy, respectively. Median contrast ratio at balance point was 0.66 in glaucoma and 1.03 in controls (P = 0.011). CONCLUSIONS: Binocular visual information processing deficits can be found in glaucoma patients with intact binocular visual field, normal visual acuity, and stereoscopy

    Are Vascularized Fibula Autografts a Long-lasting Reconstruction After Intercalary Resection of the Humerus for Primary Bone Tumors?

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    BackgroundA vascularized fibula graft (VFG) is the vascular autograft most frequently used to restore large segmental long bone defects, particularly in the upper limb. Because the use of a vascularized fibula involves an operation in an uninvolved extremity with potential morbidity, it is important to document that this type of reconstruction is successful in restoring function to the humerus. However, the long-term results of VFG after intercalary resection of the humeral diaphysis for bone tumors are still unknown.Questions/purposes(1) What was the complication rate of reconstruction? (2) What was the functional result after surgical treatment, as assessed by the Musculoskeletal Tumor Society (MSTS) score, the American Shoulder and Elbow Society (ASES) score, and Constant score? (3) What was the survivorship of these grafts free from revision and graft removal at 5, 10, and 15 years?MethodsBetween 1987 and 2021, 127 patients were treated at our institution with en bloc resection for a primary malignant or an aggressive benign bone tumor of the humerus; we excluded patients treated with extra-articular resection or amputation. Of those, 14% (18 of 127) were treated with intercalary resection of the humeral diaphysis for primary bone tumors and reconstruction with VFG, with or without a bulk allograft, and were analyzed in this retrospective study. Generally, our indications for reconstruction with VFG are intercalary resection of the humerus for primary malignant or aggressive benign bone tumors in patients with long life expectancy and high functional demands, in whom adequate bone stock of the proximal and distal epiphysis can be preserved. In 13 patients, VFG was used alone, whereas in five patients, a massive allograft was used. Our policy was to use VFG combined with a massive allograft in patients undergoing juxta-articular joint-sparing resections in which proximal osteotomy was performed close to the anatomic neck of the humerus to obtain more stable fixation and better tendinous reattachment of the rotator cuff and deltoid. All 18 patients who were treated with a VFG were available for follow-up at a minimum of 2 years (median follow-up 176 months, range 26 to 275 months), and although three have not been seen in the past 5 years and are not known to have died, they had 172, 163, and 236 months of follow-up, and were included. The median age at surgery was 25 years (range 2 to 63 years), the median humeral resection length was 15 cm (range 8 to 21 cm), and the median fibular length was 16 cm (range 12 to 23 cm). Complications and functional scores were ascertained by chart review that was performed by an individual not involved in patient care. Functional results were assessed with the MSTS score (range 0 to 30), the ASES score (range 0 to 100), and the Constant score (range 0% to 100%). Survivorship was estimated using a Kaplan-Meier survivorship estimator, which was suitable because there were few deaths in this series.ResultsSeven patients underwent a revision procedure (one radial nerve transient palsy because of screw impingement, four nonunions in three patients with one humeral head avascular necrosis, treatment for screw-related pain in one patient, and two VFG fractures), and one patient underwent VFG removal. Donor site complications were observed in four patients (one ankle valgus deformity and three claw toes - the first toe in two patients and the other toes in the third). At the final clinical control, at a median follow-up of 176 months (range 26 to 275 months), the median MSTS score was 30 of 30 (range 28 to 30), the median ASES score was 98.3 (range 93 to 100), and the median Constant score was 93.5% (range 79% to 100%). Revision-free survival was 71% (95% CI 53% to 96%) at 5 years and 57% (95% CI 37% to 88%) at 10 and 15 years; VFG removal-free survival was 94% (95% CI 83% to 100%) at 5, 10, and 15 years.ConclusionVFG appears to be an effective reconstructive option after humeral intercalary resection for primary bone tumors. These are complex procedures and should be performed by an experienced team of surgeons who recognize that complications may occur frequently in the first years after the procedure. The frequency of mechanical complications observed in the first 5 years postoperatively may be lessened by using long spanning-plate fixation, and if successful, this reconstruction provides a long-term, durable reconstruction with excellent functional results.Level of EvidenceLevel IV, therapeutic study

    Removal of ammonium from wastewater with geopolymer sorbents fabricated via additive manufacturing

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    Geopolymers have been recently explored as sorbents for wastewater treatment, thanks to their mechanical and chemical stability and to their low-energy manufacturing process. One specific application could be the removal of ammonium (NH4+) through exchange with Na+ ions. Additive manufacturing (AM) represents an especially interesting option for fabrication, as it allows to tailor the size, distribution, shape, and interconnectivity of pores, and therefore the access to charge-bearing sites. The present study provides a proof of concept for NH4+ removal from wastewater using porous geopolymer components fabricated via direct ink writing (DIW) AM approach. A metakaolin-based ink was employed for the fabrication of a log-pile structure with 45\ub0 rotation between layers, producing continuous yet tortuous macropores which are responsible for the high permeability of the sorbents. The ink consolidates in an amorphous, mesoporous network, with the mesopores acting as preferential sites for ion exchange. The printed sorbents were characterized for their physicochemical and mechanical properties and the NH4+ removal capacity in continuous-flow column experiments by using a model effluent. The lattices present high permeability and high cation exchange capacity and maintained a high amount of active ions after four cycles, allowing to reuse them multiple times

    Implant supported cantilevered fixed dental rehabilitations in partially edentulous patients : systematic review of the literature. Part I

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    Objectives: To investigate in which clinical situations a cantilever fixed implant supported restorations can be a treatment alternative and which complications are reported. Materials and Methods: Two operators screened the literature (MEDLINE, EMBASE) and performed a hand search on the main journals dealing with implantology and prosthetics until 31 December 2017. Only articles that considered cantilever implant fixed restorations with at least 10 patients and with a mean follow-up of at least 5\ua0year were selected. The outcome variables were survival of implants and prosthesis, mechanical, technical and biological complications, marginal bone loss. The review was performed according to the PRISMA statements. Risk of bias assessment was evaluated. Failure and complication rates were analysed using random effect Poisson regression models to obtain summary estimate of 5- and 10-year survival and complication rates. Results: A total of nine papers were selected for partially edentulous patients and reported high survival rate of the prosthesis. The estimated survival rate for 5\u201310\ua0years was calculated to be 98.4% for the implants and 99.2% for the rehabilitations. Mechanical, technical and biological complications were reported with a cumulative 5\u201310\ua0years complication rate of 28.66% and 26.57% for the patients and for the prosthesis, respectively. Two papers for single implant supporting 2-unit cantilever were not sufficient to draw conclusions. Conclusions: There is evidence that cantilever can be successful treatment in partially edentulous patients. In two adjacent edentulous sites, data are not yet sufficient

    Identification of most relevant variables and processes to assess the environmental impacts of remediation technologies along their life cycles: Focus on the waste management scenarios

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    The application of Life Cycle Assessment (LCA) to remediation technologies is still not a consolidated practice and it is especially lacking in the assessment of the environmental impacts associated to the management of the waste produced during remediation. This study aims at addressing these methodological gaps by identifying the typologies of waste typically generated during the remediation of a contaminated site and classifying them according to the European Waste Catalogue (EWC) codes. Thereafter, the following steps are: (i) the identification of the waste management scenarios (WMSs) applicable to the identified waste typologies, (ii) the selection of Life Cycle Assessment processes that can be used to assess the impacts of the different WMSs and (iii) the quantification and comparison of the environmental impacts caused by the different WMSs applied considering hazardousness levels to which the same waste may belong in relation to its contamination levels and characteristics: inert, non-hazardous and hazardous waste (Waste Framework Directive 2008/98/EC). As results, a matrix reporting the classes and typologies of waste, their EWC codes, their different WMSs and the suitable LCA processes from the Ecoinvent database that can be applied to each EWC within a specific WMS, has been developed. Additionally, the comparative assessment of the impacts caused by the Ecoinvent processes applicable to the same waste typology within the same WMS has been performed to support the selection of the most appropriate WMS case by case

    New record of Hippidion (Mammalia Perissodactyla) from the late Pleistocene of Buenos Aires province, Argentina

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    En este estudio se describen dos nuevos cráneos referidos a Hippidion principale (Lund) y varios elementos del esqueleto apendicular referidos a H. devillei procedentes de dos localidades clásicas de la provincia de Buenos Aires, las márgenes de los ríos Salado y Quequén Grande. Para la identificación taxonómica de los restos apendiculares, se realizó un análisis multivariante en el que se incluyeron los metacarpianos y falanges descritos y los registrados en varias localidades de Argentina y Brasil. Para la determinación de los cráneos se realizó un estudio comparativo con otros cráneos de diversas localidades. Estos hallazgos incrementan el registro de Hippidion en América del Sur y aportan nuevas evidencias sobre la cronología de sus especies en Argentina. Se realizó una datación por AMS para el ejemplar de Río Salado (MHM-P54) que ha suministrado una edad 14C 14120 ± 50 BP. En general, los sedimentos portadores en ambas localidades son referibles a la Edad Lujanense, Biozona de Equus (Amerhippus) neogeus.This study describes two new skulls referred to Hippidion(Lund) and various elements of the appendicular skeleton referred to H. devillei from two classic localities from Buenos Aires province: the Salado and Quequén Grande Rivers. For taxonomic identification of the appendicular remains was performed a multivariate analysis that included the metacarpals and phalanges described and several remains recorded in various locations in Argentina and Brazil. For the determination of the skulls was made a comparative study with other skulls from different localities. These data increasing the record of Hippidion in South America and provide new evidence about the chronological distribution of two species of Hippidion. One radiometric data was obtained by the method of AMS dating to the skull from Salado River (MHM-P54) about a 14C age 14120 ± 50 BP. In general, bearing sediments at both localities are referable to the Lujanian Age and the Biozone of Equus (Amerhippus) neogeus.Facultad de Ciencias Naturales y MuseoFacultad de Ciencias Agrarias y Forestale

    Effects of mineral amendments on trace elements leaching from pre-treated marine sediment after simulated rainfall events

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    Bauxite extraction by-products (red mud) were used to evaluate their potential ability to stabilize trace elements from dredged and aerated/humidified marine sediment. The investigated by-products were: bauxaline®(BX) that is a press-filtered red mud; bauxsol™(BS) that is a press-filtered red mud previously washed with excess of seawater, and gypsum neutralized bauxaline® (GBX). These materials were separately mixed to dredged composted sediment sample considering 5% and 20% sediment: stabilizer ratios. For pilot experiments, rainfall events were regularly simulated for 3 months. Concentrations of As, Mo, Cd, Cr, Zn, Cu, and Ni were analyzed in collected leachates as well as toxicity. Results showed that Cd, Mo, Zn, and Cu were efficiently stabilized in the solid matrix when 20% of BX, BS, and GBX was applied. Consequently, toxicity of leachates was lower than for the untreated sediment, meaning that contaminants mobility was reduced. A 5% GBX was also efficient for Mo, Zn and Cu stabilization. In all scenarios, As stabilization was not improved. Compared to all other monitored elements, Mo mobility seemed to depend upon temperature-humidity conditions during pilot experiments suggesting the need of further investigations
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