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Nomenclatura Unesco > (22) Física > (2209) Óptica
(2209.01) Espectroscopía de absorción (2209.02) Cinematografía
(2209.03) Colorimetría (2209.04) Espectroscopía de emisión
(2209.05) Fibras ópticas (2209.06) Óptica geométrica
(2209.07) Holografía (2209.08) Iluminación
(2209.09) Radiación infrarroja (2209.10) Láseres
(2209.11) Luz (2209.12) Microscopios
(2209.13) Óptica no lineal (2209.14) Propiedades ópticas de los sólidos
(2209.15) Optometría (2209.16) Instrumentos fotográficos
(2209.17) Fotografía (2209.18) Fotometría
(2209.19) Óptica física (2209.20) Radiometría
(2209.21) Espectroscopía (2209.22) Radiación ultravioleta
(2209.23) Radiación visible (2209.24) Física de la visión
(2209.90) Tratamiento digital. Imágenes (2209.99) Otras (especificar)

Categorías relacionadas:
(3311.11) Instrumentos ópticos

Mostrando recursos 1 - 20 de 25,046

1. Effects of localmelatonin application on post-extraction sockets after third molar surgery: a pilot study - Fernández-Tresguerres Hernández-Gil, Isabel; Ortega Aranegui, Ricardo; López Quiles, Juan; Cobo Vázquez, Carlos
Objectives: The purpose of this study was to assess the anti-inflammatory, analgesic and osteogenic early effects of melatonin on post-extraction sockets ofpatients requiring third molars extraction. Study Design: A randomized, triple-blind clinical trial was made using a split-mouth design. Both lower third molars of 10 patients were extracted and 3 mg of local melatonin or placebo were applied. Concentrations of interleukin-6 and nitrotyrosine were determined on samples of the clot from the socket by independent ELISA tests. Radiographic bone density was evaluated by measuring Hounsfield Units in panoramic and cross sections obtained by digital scanner. Statistycal analysis by Kolmogorov-Smirnov test was performed for ELISA data. Bone density...

2. The role of high-level visual areas in short- and longer-lasting forms of neural plasticity - Pavan, Andrea; Campana, Gianluca; Maniglia, Marcello; Casco, Clara
Striate and extrastriate neurons present short-term synaptic depression and facilitation in response to brief stimulations. Recent psychophysical studies have shed light on some possible relationships between these short-term forms of neural plasticity and of psychophysical behavior. It has been shown that a brief adaptation to directional motion biases the perceived direction of a subsequently presented ambiguous test pattern towards the same direction to that of the adaptation (rapid visual motion priming--rVMP), but only after brief (40ms) adaptation-test blank intervals. Although when the adaptation duration is increased, the perceived motion direction of the ambiguous test pattern is biased towards the opposite...

3. DRAFT - Mark Allman
This is a draft and is not to be reproduced or quoted without the author’s explicit permission. For the first time in history, human beings are able to quickly, accurately and efficiently communicate, trade and interact on a global scale. What makes this phenomenon possible are the rapid advances in technology (especially the computer and digitization), communication (such as, fiber optic cables, satellites and the internet) and transportation witnessed in the last century. With these advances, geography, as a social barrier, has been transcended and many aspects of social life (conversing, buying, selling, art, literature, music, philosophy, religion, politics, economics...

4. Monitoring of Environmental Effects using Optical-Fibers - Tarek Elsarnagawy Ph. D
This paper introduces the application of a single-mode optical fiber as a temperature sensor. The application is based on a Michelson-Interferometer where the optical fiber represents the arms of the Michelson-Interferometer which are affected by the external stimulus to be measured. The sensor configuration is composed of a single-mode fiber of several meters. The used light source is a Laser-diode operating at 830 nm. The signal response of this configuration is detected by means of a fringe counting electronic setup (digital readout), where the detected number of counts directly represent the amount of the external stimulus. The results are compared...

5. Functional Characterization of Retina and Optic Nerve after Acute Ocular Ischemia in Rats - Ioana M. Sonea
PURPOSE. To functionally characterize the status of the rat retina and optic nerve after acute elevation of intraocular pressure (IOP) and to determine the dynamics of the pathologic changes in the ischemic retina and optic nerve. METHODS. Retinal ischemia was induced in rats by acutely increasing the IOP (110 mm Hg/60 minutes). Direct and indi-rect pupil light reflexes (PLRs) were recorded from the nonin-jured eye, and electroretinograms (flash and flicker ERG) were recorded from the injured and control eyes before and after surgery. Amplitudes and latencies were calculated for each recording session. RESULTS. Preoperative PLRratios (indirect/direct PLR) were 76.7 2.6...

6. ETHAMBUTOL INDUCED OPTIC NEURITIS IN TWO BROTHERS - P. R. Gupta; S. D. Purohit; R. G. Sharma; K. C. Agarwal
Summary: Two cases of ethambutol induced optic neuritis are reported. The patients were brothers. Both patients developed visual defects simultaneously while on ethambutol therapy in daily dosage of 20 mg. /kg. throughout. Zinc deficiency was possibly responsible for this.

7. mitochondrial genome - Byung-ok Choi; Jung Hee Hwang; Joonki Kim; Eun Min Cho; Sun Young Cho; Su Jin Hwang; Hyang Woon Lee; Song Ja Kim; Ki Wha Chung
stroke-like episodes; MERRF, myoclonus epilepsy with ragged-red fibers; mtDNA, mitochondrial DNA; NAION, non-arteritic anterior ischemic optic neuropathy; ND5, NADH dehydrogenase subunit 5; rCRS, revised Cambridge reference sequence Mitochondrial myopathy, encephalopathy, lactic aci-dosis, and stroke-like episodes (MELAS) syndrome is a genetically heterogeneous mitochondrial disorder with variable clinical symptoms. Here, from the se-quencing of the entire mitochondrial genome, we re-port a Korean MELAS family harboring two homo-plasmic missense mutations, which were reported 9957T>C (Phe251Leu) transition mutation in the cyto-chrome c oxidase subunit 3 (COX3) gene and a novel 13849A>C (Asn505His) transversion mutation in the NADH dehydrogenase subunit 5 (ND5) gene. Neither of...

8. International Conference on Computer Systems and Technologies- CompSysTech ’ 2005 An Algorithm for Synthesis of Aperiodic Optical Orthogonal Codes - Borislav Y. Bedzhev; Zhaneta N. Tasheva; Borislav P. Stoyanov; Er P. Milev
Abstract: Communication and computer systems have formed a common space where the quantity and quality of offered services are growing very fast at present. This situation leads to necessity of extreme optimal using of the connecting channels. A promising approach to the solution to this hard technical problem is applying of optic fibre systems with Code Division Multiple Access. The employing a special class of codes, named Optical Orthogonal Codes, enables to simplify greatly the complexity of the optic fibre system, to implement it with available technology, and to achieve potentially higher transmission efficiency. Unfortunately some important problems in the...

9. Further Clinical and Pathological Observations on Leber's Optic Atrophy. By - Denis Williams M. D; J. N. Cumings; Sir Aubrey Lewis; W. H. Mcmenemey; D. W. C. Northfield; S. Nevin M. D; J. Hume Adams; William Blackwood; John Wilson
F.R.C.S.Ed., F.R.S.Ed.

10. Abnormal auditory experience induces frequency-specific adjustments in unit tuning for binaural localization cues in the optic tectum of juvenile owls - Joshua I. Gold; Eric I. Knudsen
Early auditory experience shapes the auditory spatial tuning of neurons in the barn owl’s optic tectum in a frequency-dependent manner. We examined the basis for this adaptive plasticity in terms of changes in tuning for frequency-specific interaural time differences (ITDs) and level differences (ILDs), the dominant sound localization cues. We characterized broad-band and narrowband ITD and ILD tuning in normal owls and in owls raised with an acoustic filtering device in one ear that caused frequency-dependent changes in sound timing and level. In normal owls, units were tuned to frequency-specific ITD and ILD values that matched those produced by sound...

11. Printed in Great Britain CLASSES OF LIGHT-EVOKED RESPONSE IN THE RETINA OF STROMBUS - N. Quandt; Howard; L. Gillary
Two general classes of light-evoked responses were recorded intra-cellularly from the retina of Strombus luhuanus. In one class, retinal illumina-tion caused depolarization, the amplitude of which was graded with light intensity. In the other, it produced hyperpolarization and concomitant inhibition of repetitive action potentials. There were two types of depolarizing waveform. Each was associated with a different type of intraccllular recording site, characterized on the basis of electrical properties in the dark. In general, the type of response with a more rapid rate of decay was recorded from a site which exhibited a lower resting potential, higher input resistance, and...

12. Electro-optic techniques in electron beam diagnostics - J. Van Tilborg; N. H. Matlis; G. R. Plateau; W. P. Leemans
Electron accelerators such as laser wakefield accel-erators, linear accelerators driving free electron lasers, or femto-sliced synchrotrons, are capable of producing femtosecond-long electron bunches. Single-shot character-ization of the temporal charge profile is crucial for opera-tion, optimization, and application of such accelerators. A variety of electro-optic sampling (EOS) techniques exists for the temporal analysis. In EOS, the field profile from the electron bunch (or the field profile from its coherent radia-tion) will be transferred onto a laser pulse co-propagating through an electro-optic crystal. This paper will address the most common EOS schemes and will list their advantages and limitations. Strong points that...

13. Giant Cell Reparative Granuloma of the Orbit Associated with Cherubism - Ramon L. Font; Gonzalo Blanco; Charles N. Soparkar; James R. Patrinely; Mary L. Ostrowski
Purpose: To report a case of cherubism with extensive, bilateral orbital involvement occurring in a 27-year-old woman who had the diagnosis established at the age of 4 years. Design: Single interventional case report. Intervention: Ophthalmologic examination and computed tomography were performed. The patient under-went multiple surgical excisions using a bicoronal and transorbital approach. The excised orbital tissues were studied histopathologically. Results: Computed tomography showed bilateral inferior lateral masses involving the orbital floors and producing marked superior displacement of the orbital contents. The intrinsic expansile bone lesions involved the inferior and lateral orbital walls with apical compression of the optic nerves....

14. Fiber-Optic Current and Voltage Sensors for High-Voltage Substations - K. Bohnert; P. Gabus; H. Brändle; Aftab Khan
We report on ABB’s fiber-optic current and voltage transducers and their applications in high-voltage substations. We consider bulk-optics and all-fiber current sensors and voltage sensors that exploit the electro-optic effect in BGO and the piezo-electric effect in quartz.

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Abstract – – We propose in this paper a new methodology to generate the output signals of an artificial retinal stimulator to selectively stimulate the human optic nerve. The output signal generator is based on clinical electrical patterns recorded from a multi-focal electroretinography. An adaptive filter is proposed to estimate the weights of a set of finte impulse response (FIR) filters, that generate each electrical response highly correlated with the visual patterns. The proposed model let to analyse the behaviour of the retina coded signals with a set of linear FIR filters.

16. CLINICAL SCIENCES Comparison of Optic Disc Margin Identified by Color Disc Photography and High-Speed Ultrahigh-Resolution Optical Coherence Tomography - Richard A. Bilonick; Phd Larry Kagemann; Msc Michelle; L. Gabriele; Bsc Kyung; Rim Sung
Objective: To determine the correspondence between optic disc margins evaluated using disc photography (DP) and optical coherence tomography (OCT). Methods:FromMay1,2005, throughNovember10,2005, 17healthyvolunteers(17eyes)hadrasterscans(180frames, 501 samplings per frame) centered on the optic disc taken with stereo-optic DP and high-speed ultrahigh-resolution OCT(hsUHR-OCT).Twoimageoutputswerederivedfrom the hsUHR-OCT data set: an en face hsUHR-OCT fundus imageandasetof180framesofcross-sectionalimages.Three ophthalmologists independentlyandinamasked, random-ized fashion marked the disc margin on the DP, hsUHR-OCTfundus,andcross-sectional imagesusingcustomsoft-ware.Disc size (areaandhorizontal andverticaldiameters) and location of the geometric disc center were compared

Abstract: A new in situ test, called the Hydromechanical Pulse Injection Test (HMPIT), is proposed for determination of rock-fracture hydromechanical properties. Compared to a conventional hydraulic pulse test, which typically uses only the pulse-pressure decrease stage, the HMPIT provides interpretable high-frequency data of both the pulse-pressure increase and decrease stages. Moreover, the HMPIT provides simultaneous high-frequency data of both pressure and fracture-mechanical displacement simultaneously, and can therefore be used to assess both hydraulic permeability and normal stiffness of fractures in rock. The paper describes the specialized field test equipment for HMPIT (with fiber-optic sensors), its application in measuring the in...

18. Characterisation of phototransistors by beating of lasers - Jean-luc Polleux; Anne-laure Billabert-germond; Gérard Hincelin; Christian Rumelhard
Abstract: In the design of communication systems like radio on fibre, an important step is the characterisation of opto-microwave receivers. This paper presents two equipments based on the generation of millimetre-waves by the beating of lasers. The sources of the two benches are different. So the particularities of each of them will be showed. An example of application is given by the characterisation of an Heterojunction Photo Transistor (HPT). I. Overview of the techniques of microwave single-tone-signal transport by an optical carrier Different fibre optic communication systems imply components having to work at very high frequencies. It is the case,...

Purpose: To study the effects of geranylgeranylacetone (GGA) on the expression of inducible (HSP72) and constitutive (HSC70) heat shock proteins (HSPs) on retinal ganglion cells (RGCs) in a rat model of glaucoma. Methods: Adult Wistar rats were given intraperitoneal injections of GGA, 200 mg/kg daily. Western blot analysis and immunohistochemical staining for HSP72 and HSC70 were performed after 1, 3, and 7 days of GGA administration. After 7 days of GGA pretreatment, intraocular pressure (IOP) was elevated unilaterally by repeated trabecular argon laser photocoagulation 5 days after intracameral injection of india ink. After the first laser photocoagulation, GGA was given...

20. Review Ophthalmological manifestations in VHL and NF 1: pathological and diagnostic - Klaus-martin Kreusel
Von Hippel–Lindau disease (VHL) and neurofibromatosis type 1 (NF 1) are hereditary multitumor syndromes that show associated ocular manifestations. Capillary retinal angioma, a benign vascular tumor, is the classical ocular lesion in VHL. It often appears as the first manifestation of the disease and may thus lead to the diagnosis of VHL. Since small angiomas can be treated easily by laser photocoagulation, a regular ocular screening of VHL patients is recommended. Ocular manifestations of NF 1 are more diverse as compared to VHL. Lisch nodules of the iris are an important diagnostic criteria of NF 1 since they can be...

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