466 research outputs found

    Optical Coherence Tomography Angiography of the Optic Disc; an Overview.

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    Different diseases of the optic disc may be caused by or lead to abnormal vasculature at the optic nerve head. Optical coherence tomography angiography (OCTA) is a novel technology that provides high resolution mapping of the retinal and optic disc vessels. Recent studies have shown the ability of OCTA to visualize vascular abnormalities in different optic neuropathies. In addition, quantified OCTA measurements were found promising for differentiating optic neuropathies from healthy eyes

    Angioarchitectural evolution of clival dural arteriovenous fistulas in two patients.

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    Dural arteriovenous fistulas (dAVFs) may present in a variety of ways, including as carotid-cavernous sinus fistulas. The ophthalmologic sequelae of carotid-cavernous sinus fistulas are known and recognizable, but less commonly seen is the rare clival fistula. Clival dAVFs may have a variety of potential anatomical configurations but are defined by the involvement of the venous plexus just overlying the bony clivus. Here we present two cases of clival dAVFs that most likely evolved from carotid-cavernous sinus fistulas

    Macular Microcysts in Mitochondrial Optic Neuropathies: Prevalence and Retinal Layer Thickness Measurements.

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    PurposeTo investigate the thickness of the retinal layers and to assess the prevalence of macular microcysts (MM) in the inner nuclear layer (INL) of patients with mitochondrial optic neuropathies (MON).MethodsAll patients with molecularly confirmed MON, i.e. Leber's Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), referred between 2010 and 2012 were enrolled. Eight patients with MM were compared with two control groups: MON patients without MM matched by age, peripapillary retinal nerve fiber layer (RNFL) thickness, and visual acuity, as well as age-matched controls. Retinal segmentation was performed using specific Optical coherence tomography (OCT) software (Carl Zeiss Meditec). Macular segmentation thickness values of the three groups were compared by one-way analysis of variance with Bonferroni post hoc corrections.ResultsMM were identified in 5/90 (5.6%) patients with LHON and 3/58 (5.2%) with DOA. The INL was thicker in patients with MON compared to controls regardless of the presence of MM [133.1±7μm vs 122.3±9μm in MM patients (p<0.01) and 128.5±8μm vs. 122.3±9μm in no-MM patients (p<0.05)], however the outer nuclear layer (ONL) was thicker in patients with MM (101.4±1mμ) compared to patients without MM [77.5±8mμ (p<0.001)] and controls [78.4±7mμ (p<0.001)]. ONL thickness did not significantly differ between patients without MM and controls.ConclusionThe prevalence of MM in MON is low (5-6%), but associated with ONL thickening. We speculate that in MON patients with MM, vitreo-retinal traction contributes to the thickening of ONL as well as to the production of cystic spaces

    The Use of Energy Dispersive X-ray Diffraction (EDXD) for the Investigation of the Structural and Compositional Features of Old and Modern Papers

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    Abstract This work reports the first application of the Energy Dispersive X-ray Diffraction (EDXD) for the investigation of the structural and compositional features of old and modern papers. Based on the differences observed among various types of paper and building an appropriate database we expect to be able to rapidly identify the provenance of the paper itself using a fast non-destructive technique. This result is quite interesting in the field of art conservation and archaeometry

    Effectiveness of pre-procedural rinsing with essential oils-based mouthrinse to reduce aerosol contamination of periodontitis patients

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    This research aims to evaluate the effectiveness of pre-procedural rinsing using essential oils-mouthwash (Listerine®) in reducing bioaerosol contamination in a dental clinic. Thirty (30) subjects who consisted of those receiving treatment for periodontitis problems were randomly assigned to rinse with either 20 mL of Listerine® or 20 mL of placebo as control rinse. Every subject was instructed to gargle using the rinse for 1 min. Microbial samples of environmental air and saliva were collected before and after the rinse. All samples were further analyzed for total plate counts to measure the microbial level. Rinsing using Listerine® showed significant reduction in the level of microbial load in saliva compared to the control mouthrinses. Analysis done at three defined distance intervals from the operating site showed the level of bioaerosol contamination was highest at distance nearest to the treatment point of 1 ft. Based on counts of cfu, there was higher presence of microbial contaminant in bioaerosols of the control-rinsed group compared to the test-rinsed group using Listerine®. Therefore, it can be concluded that rinsing using Listerine® was effective towards reducing the microorganisms in saliva and oral cavity in general

    The geometry of entanglement: metrics, connections and the geometric phase

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    Using the natural connection equivalent to the SU(2) Yang-Mills instanton on the quaternionic Hopf fibration of S7S^7 over the quaternionic projective space HP1S4{\bf HP}^1\simeq S^4 with an SU(2)S3SU(2)\simeq S^3 fiber the geometry of entanglement for two qubits is investigated. The relationship between base and fiber i.e. the twisting of the bundle corresponds to the entanglement of the qubits. The measure of entanglement can be related to the length of the shortest geodesic with respect to the Mannoury-Fubini-Study metric on HP1{\bf HP}^1 between an arbitrary entangled state, and the separable state nearest to it. Using this result an interpretation of the standard Schmidt decomposition in geometric terms is given. Schmidt states are the nearest and furthest separable ones lying on, or the ones obtained by parallel transport along the geodesic passing through the entangled state. Some examples showing the correspondence between the anolonomy of the connection and entanglement via the geometric phase is shown. Connections with important notions like the Bures-metric, Uhlmann's connection, the hyperbolic structure for density matrices and anholonomic quantum computation are also pointed out.Comment: 42 page
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