736 research outputs found
Short-Facelift Approach in Temporal Artery Biopsy: Is It Safe?
Giant cell arteritis (GCA) is a quite common panarteritis of the elderly that affects medium- and large-size arteries. Despite the increasing role of imaging with advancing technology, the gold standard for the diagnosis of GCA is still the temporal artery biopsy. A described complication of superficial temporal artery biopsy (STAB), for which incidence is not clear, is the accidental damage of the frontal branch of the facial nerve. In this paper, we described the short-scar facelift surgical approach for STAB on 23 consecutive patients who underwent unilateral superficial temporal artery biopsy for GCA suspicion. We collected data in terms of postoperative complications, biopsy specimen length, biopsy result and cosmetic appearance of the scar. In our experience, this surgical approach combines the advantage of avoiding incisions within the dangerous anatomical area, minimizing the risk of facial nerve damage, with an acceptable complication rate and a good final aesthetic result which avoids visible scarring
Testing the Dispersion of Nanoparticles in a Nanocomposite with an Ultra-Low Fill Content Using a Novel Non-Destructive Evaluation Technique
A non-destructive evaluation (NDE) technique capable of testing the dispersion of nanoparticles in a nanocomposite would be of great use to the industry to check the quality of the products made and to ensure compliance with their specifications. Very few NDE techniques found in the literature can evaluate the level of dispersion of the nanoparticles in the whole nanocomposite. Here, a recently developed NDE technique based on pulsed phase thermography (PPT) in transmission mode was used to assess the particle dispersion in ultra-low, less than 0.05 wt%, Ag enriched polymeric based nanocomposite manufactured with an innovative nano-coating fragmentation technique. The phasegrams obtained with the presented technique clearly showed clusters or bundles of Ag nanoparticles when present, down to the size of 6 µm. Therefore, the new NDE approach can be applied to verify that the expected levels of dispersion are met in the production process
Doubling the Mechanical Properties of Spider Silk by C60 Supersonic Molecular Beam Epitaxy
Spider silk is one of the most fascinating natural materials, owing to its outstanding mechanical properties. In fact, it is able to combine usually self-excluding properties, like strength and toughness that synthetic fibers fail to replicate. Here, we report a method to further enhance the already excellent mechanical properties of spider's silk, producing nanocomposite fibers where the matrix of spider silk is reinforced with C60 molecules. These are deposited by Supersonic Molecular Beam Epitaxy (SuMBE) and are able to efficiently interact with silk, as evidenced by XPS analysis. As a consequence, upon proper adjustment of the fullerene kinetic energy, the treated fibers show improved strength, Young's modulus and toughness
General Relativistic Dynamics of Irrotational Dust: Cosmological Implications
The non--linear dynamics of cosmological perturbations of an irrotational
collisionless fluid is analyzed within General Relativity. Relativistic and
Newtonian solutions are compared, stressing the different role of boundary
conditions in the two theories. Cosmological implications of relativistic
effects, already present at second order in perturbation theory, are studied
and the dynamical role of the magnetic part of the Weyl tensor is elucidated.Comment: 12 pages , DFPD 93/A/6
Fractoluminescence characterization of the energy dissipated during fast fracture of glass
Fractoluminescence experiments are performed on two kinds of silicate
glasses. All the light spectra collected during dynamic fracture reveal a black
body radiator behaviour, which is interpreted as a crack velocity-dependent
temperature rise close to the crack tip. Crack velocities are estimated to be
of the order of 1300 m.s and fracture process zones are shown to extend
over a few nanometers.Comment: Accepted for publication in Europhysics Letters; 5 pages; 4 figure
A Plant Bioreactor for the Synthesis of Carbon Nanotube Bionic Nanocomposites
Bionic composites are an emerging class of materials produced exploiting living organisms as reactors to include synthetic functional materials in their native and highly performing structures. In this work, single wall carboxylated carbon nanotubes (SWCNT-COOH) were incorporated within the roots of living plants of Arabidopsis thaliana. This biogenic synthetic route produced a bionic composite material made of root components and SWCNT-COOH. The synthesis was possible exploiting the transport processes existing in the plant roots. Scanning electrochemical microscopy (SECM) measurements showed that SWCNT-COOH entered the vascular bundles of A. thaliana roots localizing within xylem vessels. SWCNT-COOH preserved their electrical properties when embedded inside the root matrix, both at a microscopic level and a macroscopic level, and did not significantly affect the mechanical properties of A. thaliana roots
Micromechanical model for protein materials: From macromolecules to macroscopic fibers
We propose a model for the mechanical behavior of protein materials. Based on
a limited number of experimental macromolecular parameters (persistence and
contour lengths, rate of unfolding dissipation) we obtain the macroscopic
behavior of keratin fibers (human, cow, and rabbit hair), taking into account
the damage and residual stretches effects which are fundamental in many
functions of life. We support our theoretical results by showing that our model
is robust and able to reproduce with high quantitive accuracy the cyclic
experimental behavior of different keratinous protein materials we tested. We
also show the capability of describing, even if with lower precision, the
dissipation and permanent strain effects in spider silks
Functional Connectivity Changes After Initial Treatment With Fingolimod in Multiple Sclerosis
On the basis of recent functional MRI studies, Multiple Sclerosis (MS) has been interpreted as a multisystem disconnection syndrome. Compared to normal subjects, MS patients show alterations in functional connectivity (FC). However, the mechanisms underlying these alterations are still debated. The aim of the study is to investigate resting state (RS) FC changes after initial treatment with fingolimod, a proven anti-inflammatory and immunomodulating agent for MS. We studied 32 right-handed relapsing-remitting MS patients (median Expanded Disability Status Scale: 2.0, mean disease duration: 8.8 years) who underwent both functional and conventional MRI with a 3 Tesla magnet. All assessments were performed 3 weeks before starting fingolimod, then, at therapy-initiation stage and at month 6. Each imaging session included scans at baseline (run1) and after (run2) a 25-min, within-session, motor-practice task, consisting of a paced right-thumb flexion. FC was assessed using a seed on the left primary motor cortex to obtain parametric maps at run1 and task-induced FC change (run2-run1). Comparison between 3-week before- and fingolimod start sessions accounted for a test-retest effect. The main outcome was the changes in both baseline and task-induced changes in FC, between initiation and 6 months. MRI contrast enhancement was detected in 14 patients at initiation and only in 3 at month 6. There was a significant improvement (p < 0.05) in cognitive function, as measured by the Paced Auditory Serial Addition Task, at month 6 compared to initiation. After accounting for test-retest effect, baseline FC significantly decreased at month 6, with respect to initiation (p < 0.05, family-wise error corrected) in bilateral occipito-parietal areas and cerebellum. A task-induced change in FC at month 6 showed a significant increment in all examined sessions, involving not only areas of the sensorimotor network, but also posterior cortical areas (cuneus and precuneus) and areas of the prefrontal and temporal cortices (p < 0.05, family-wise error corrected). Cognitive improvement at month 6 was significantly (p < 0.05) related to baseline FC reduction in posterior cortical areas. This study shows significant changes in functional connectivity, both at baseline and after the execution of a simple motor task following 6 months of fingolimod therapy
Functional Connectivity Changes After Initial Treatment With Fingolimod in Multiple Sclerosis
On the basis of recent functional MRI studies, Multiple Sclerosis (MS) has been interpreted as a multisystem disconnection syndrome. Compared to normal subjects, MS patients show alterations in functional connectivity (FC). However, the mechanisms underlying these alterations are still debated. The aim of the study is to investigate resting state (RS) FC changes after initial treatment with fingolimod, a proven anti-inflammatory and immunomodulating agent for MS. We studied 32 right-handed relapsing-remitting MS patients (median Expanded Disability Status Scale: 2.0, mean disease duration: 8.8 years) who underwent both functional and conventional MRI with a 3 Tesla magnet. All assessments were performed 3 weeks before starting fingolimod, then, at therapy-initiation stage and at month 6. Each imaging session included scans at baseline (run1) and after (run2) a 25-min, within-session, motor-practice task, consisting of a paced right-thumb flexion. FC was assessed using a seed on the left primary motor cortex to obtain parametric maps at run1 and task-induced FC change (run2-run1). Comparison between 3-week before- and fingolimod start sessions accounted for a test-retest effect. The main outcome was the changes in both baseline and task-induced changes in FC, between initiation and 6 months. MRI contrast enhancement was detected in 14 patients at initiation and only in 3 at month 6. There was a significant improvement (p < 0.05) in cognitive function, as measured by the Paced Auditory Serial Addition Task, at month 6 compared to initiation. After accounting for test-retest effect, baseline FC significantly decreased at month 6, with respect to initiation (p < 0.05, family-wise error corrected) in bilateral occipito-parietal areas and cerebellum. A task-induced change in FC at month 6 showed a significant increment in all examined sessions, involving not only areas of the sensorimotor network, but also posterior cortical areas (cuneus and precuneus) and areas of the prefrontal and temporal cortices (p < 0.05, family-wise error corrected). Cognitive improvement at month 6 was significantly (p < 0.05) related to baseline FC reduction in posterior cortical areas. This study shows significant changes in functional connectivity, both at baseline and after the execution of a simple motor task following 6 months of fingolimod therapy
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