196,264 research outputs found
Recent developments in the management of dry age-related macular degeneration
No full textElisa Buschini, Antonio M Fea, Carlo A Lavia, Marco Nassisi, Giulia Pignata, Marta Zola, Federico M Grignolo Ospedale Oftalmico, Ophthalmic Section, Department of Clinical Pathophysiology, University of Turin, Turin, Italy Abstract: Dry age-related macular degeneration (AMD), also called geographic atrophy, is characterized by the atrophy of outer retinal layers and retinal pigment epithelium (RPE) cells. Dry AMD accounts for 80% of all intermediate and advanced forms of the disease. Although vision loss is mainly due to the neovascular form (75%), dry AMD remains a challenge for ophthalmologists because of the lack of effective therapies. Actual management consists of lifestyle modification, vitamin supplements, and supportive measures in the advanced stages. The Age-Related Eye Disease Study demonstrated a statistically significant protective effect of dietary supplementation of antioxidants (vitamin C, vitamin E, beta-carotene, zinc, and copper) on dry AMD progression rate. It was also stated that the consumption of omega-3 polyunsaturated fatty acids, such as docosahexaenoic acid and eicosapentaenoic acid, has protective effects. Other antioxidants, vitamins, and minerals (such as crocetin, curcumin, and vitamins B9, B12, and B6) are under evaluation, but the results are still uncertain. New strategies aim to 1) reduce or block drusen formation, 2) reduce or eliminate inflammation, 3) lower the accumulation of toxic by-products from the visual cycle, 4) reduce or eliminate retinal oxidative stress, 5) improve choroidal perfusion, 6) replace/repair or regenerate lost RPE cells and photoreceptors with stem cell therapy, and 7) develop a target gene therapy. Keywords: dry AMD, geographic atrophy, new AMD therap
80 A/cm2 ELECTRON BEAMS FROM METAL TARGETS IRRADIATED BY A KRCL AND XECL EXCIMER LASER
No full textDue to the growing demand for high-current and long-duration electron-beam devices, laser electron sources were investigated in our laboratory. Experiments on electron-beam generation and propagation from aluminium and copper targets illuminated by XeCl (308 nm) and KrCl (222 nm) excimer lasers, were carried out under plasma ignition due to laser irradiation. This plasma supplied a spontaneous accelerating electric field of about 370kV/m without an external accelerating voltage. By applying the modified one-dimensional Poisson equation, we computed the expected current and we also estimated the plasma concentration during the accelerating process. At 40 kV of accelerating voltage, an output current pulse of about 80 A/cm(2) was detected from an Al target irradiated by the shorter wavelength laser
Experimental results of transmutation of elements observed in etched Pd samples by an excimer laser”, Fusion Technology, 31, 247-52 (2000)
No full textFusion Technology, 31, 247-52 (2000
Il repubblicanesimo storico di Pantaleo Ingusci
No full textLa storia del repubblicanesimo meridionale negli anni '20-'30 del'900 è strettamente legata alla figura di Egidio Reale, amico di Carlo Rosselli, di Guglielmo Ferrero, Gaetano Salvemini e di altri dirigenti del movimento di Giustizia e Libertà. Fu anello di collegamento fra la Resistenza italiana e la Resistenza francese, fra il Governo Alleato e i partigiani. Pantaleo Ingusci e i fratelli Reale (Egidio e Attilio) ben rappresentano la tradizione mazziniana e ghisleriana del neorepubblicanesimo
Effects of physical stresses on radish seed germination and growth
No full textIn this work we explore the consequences on variable magnetic fields applied to radish seeds (Raphanus sativum L.) on germination and seedling growth. Three, different alternate magnetic fields have been tested having a high intensity, 40 mT, at very low frequency, 0.2 Hz (B0. 2), a low intensity, 577 μT, at low frequency, 370 kHz (B370), and a very low intensity, about 250 nT, at ultra high frequency, 900 MHz (RF900). These last generate electromagnetic waves which are nowadays very used for mobile communications. Groups of uniform radish seeds were exposed to alternate magnetic fields at three duration time values: i) 120 h (BO. 2/1), 260 h (B0. 2/2) and 360 h (B0. 2/3) at high intensity and very low frequency, 0.2 Hz; ii) 120 h (B370/1), 260 h (B370/2), 360 h (B370/3) at low intensity and low frequency, 370 kHz; iii) 120 h (RF/1), 260 h (RF/2), 360 h (RF/3) at very low intensity and ultra high frequency, 900 MHz. Furthermore, another group of seeds was treated by laser beams of 248 nm wavelength whose magnetic field is coupled to an electric field. These two fields, by the Planck theory, origin the quantum energy, expresses by photons. Therefore, in the laser-matter interaction photons are absorbed dependent on laser shots. Again, we performed experiments at three duration time values that applied: 30 kshots (KrF/1), 80 kshots (KrF/2) and 135 kshots (KrF/3) at 40 mJcm2/fluence. The magnetic field and electric field presented by the laser beam are approximatively 250 kVm/and 850 μT, respectively. All treatments were performed at room temperature. Both untreated seeds and each group of seeds exposed to the physical stresses were ..
Ocular Imaging for Enhancing the Understanding, Assessment, and Management of Age-Related Macular Degeneration
No full textAge-related macular degeneration (AMD) is a progressive neuro-retinal disease and the leading cause of central vision loss among elderly individuals in the developed countries. Modern ocular imaging technologies constitute an essential component of the evaluation of these patients and have contributed extensively to our understanding of the disease. A challenge with any review of ocular imaging technologies is the rapid pace of progress and evolution of these instruments. Nonetheless, for proper and optimal use of these technologies, it is essential for the user to understand the technical principles underlying the imaging modality and their role in assessing the disease in various settings. Indeed, AMD, like many other retinal diseases, benefits from a multimodal imaging approach to optimally characterize the disease. In this chapter, we will review the various imaging technologies currently used in the assessment and management of AMD
Photoelectron-Beam Generation Up To Short Threshold
No full textWe report on the behaviour of electron beams extracted from metal cathodes illuminated by a powerful XeCl-laser beam. The target materials used were Zn, Y and Ge. During the electron extraction a plasma was created on the target surface. At high laser energies and high accelerating voltages the plasma introduces an impedance into the cathode-anode region. Owing to the plasma formation short-circuits occur in the accelerating region thus limiting the maximum output current. Under our experimental conditions, a laser energy of 27 mJ and 3 mm of distance cathode-anode, a maximum output corrent density of about 4.9 A/cm2 was obtained with the Zn cathode. The yttrium target may provide a higher current density but so far it could not be demonstrated due to plasma formation which short-circuits the anode-cathode region. The experimental results obtained with Ge targets are interesting for obtaining short electron pulses
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