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  1 / 14507 MEDLINE  
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[PMID]:29475304
[Au] Autor:Chacón A; Ruiz C
[Ti] Título:Attosecond delay in the molecular photoionization of asymmetric molecules.
[So] Source:Opt Express;26(4):4548-4562, 2018 Feb 19.
[Is] ISSN:1094-4087
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We report theoretical calculations of the delay in photoemission from CO with particular emphasis on the role of the ultrafast electronic bound dynamics. We study the delays in photoionization in the HOMO and HOMO-1 orbitals of the CO molecule by looking into the stereo Wigner time delay technique. That compares the delay in photoemission from electrons emitted to the left and right to extract structural and dynamical information of the ionization process. For this we apply two techniques: The attosecond streak camera and the time of flight technique. Although they should provide the same results we have found large discrepancies of up to 36 in the case of HOMO, while for the HOMO-1 we obtain the same results with the two techniques. We have found that the large time delays observed in the HOMO orbital with the streaking technique are a consequence of the resonant transition triggered by the streaking field. This resonant transition produces a bound electron wavepacket that modifies the measurements of delay in photoionization. As a result of this observation, our technique allows us to reconstruct the bound wavepacket dynamics induced by the streaking field. By measuring the expected value of the electron momentum along the polarization direction after the streaking field has finished, we can recover the relative phase between the complex amplitudes of the HOMO and LUMO orbitals. These theoretical calculations pave the way for the measurement of ultrafast bound-bound electron transitionsand its crucial role for the delay in photoemission observation.
[Mh] Termos MeSH primário: Monóxido de Carbono/química
Modelos Teóricos
Óptica e Fotônica
Fotoquímica
[Mh] Termos MeSH secundário: Luz
Teoria Quântica
Espalhamento de Radiação
Análise Espectral
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
7U1EE4V452 (Carbon Monoxide)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180225
[St] Status:MEDLINE
[do] DOI:10.1364/OE.26.004548


  2 / 14507 MEDLINE  
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[PMID]:29475280
[Au] Autor:Yuan R; Ye WJ; Xing HY; Li ZJ; Sun TT; Sun YB; Zhu JL; Xiang Y; Zhang ZY; Cai ML
[Ti] Título:Continuously adjustable period optical grating based on flexoelectric effect of a bent-core nematic liquid crystal in planar cells.
[So] Source:Opt Express;26(4):4288-4299, 2018 Feb 19.
[Is] ISSN:1094-4087
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The structures of flexodomains, which are similar to optical gratings and can be controlled by the amplitude of applied voltage and temperature, were verified through polarizing microscopy and light diffraction techniques. The properties of the optical grating induced by a bent-core nematic liquid crystal in planar cells with varied cell gaps and pretilt angles were studied. The period of optical grating decreases with the increase in the amplitude of the applied voltage and pretilt angle. In addition, the period increases with the increase in cell gap and temperature. The period of optical grating has a linear relationship with temperature. The continuously adjustable period has the potential to become an important and extended application of optical grating.
[Mh] Termos MeSH primário: Cristais Líquidos/química
Modelos Químicos
Modelos Moleculares
Óptica e Fotônica
[Mh] Termos MeSH secundário: Simulação por Computador
Módulo de Elasticidade
Campos Eletromagnéticos
Teste de Materiais
Refratometria/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180225
[St] Status:MEDLINE
[do] DOI:10.1364/OE.26.004288


  3 / 14507 MEDLINE  
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[PMID]:29475281
[Au] Autor:Chen X; Gao J; Kang B
[Ti] Título:Achieving a tunable metasurface based on a structurally reconfigurable array using SMA.
[So] Source:Opt Express;26(4):4300-4308, 2018 Feb 19.
[Is] ISSN:1094-4087
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:We introduce a structurally reconfigurable metasurface which is made of shape memory alloys (SMA). It could change the morphology of the unit cells repeatedly as we expect in response to a thermal stimulus and realize a tuning range from 13.3GHz to 17.2GHz for both polarizations simultaneously. Equivalent circuit models describe the operational principle and design methodology, the physical mechanism is interpreted with the variation of surface current distribution on the structure. The experimental results coincide with the numerical simulations, making the all-metal metasurface an attractive choice for manipulating the electromagnetic wave in a wide range of spectrums with the merits of higher controllability for dynamic behavior and greater freedom for design and manufacturing.
[Mh] Termos MeSH primário: Ligas/química
Campos Eletromagnéticos
Eletrônica/instrumentação
Óptica e Fotônica/instrumentação
[Mh] Termos MeSH secundário: Desenho de Equipamento
Modelos Teóricos
Condutividade Térmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Alloys)
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180225
[St] Status:MEDLINE
[do] DOI:10.1364/OE.26.004300


  4 / 14507 MEDLINE  
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[PMID]:29439230
[Au] Autor:Amo A
[Ad] Endereço:Université de Lille, CNRS, UMR 8523, Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), F-59000 Lille, France. alberto.amo@univ-lille1.fr.
[Ti] Título:When quantum optics meets topology.
[So] Source:Science;359(6376):638-639, 2018 02 09.
[Is] ISSN:1095-9203
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Óptica e Fotônica
Teoria Quântica
[Pt] Tipo de publicação:JOURNAL ARTICLE; COMMENT
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180227
[Lr] Data última revisão:
180227
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180214
[St] Status:MEDLINE
[do] DOI:10.1126/science.aar7396


  5 / 14507 MEDLINE  
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[PMID]:29227508
[Au] Autor:Tandogan T; Son HS; Choi CY; Knorz MC; Auffarth GU; Khoramnia R
[Ti] Título:Laboratory Evaluation of the Influence of Decentration and Pupil Size on the Optical Performance of a Monofocal, Bifocal, and Trifocal Intraocular Lens.
[So] Source:J Refract Surg;33(12):808-812, 2017 Dec 01.
[Is] ISSN:1081-597X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To assess the influence of decentration and aperture size on the optical quality of different intraocular lenses (IOLs) of the same material, body design, and refractive power using standardized optical bench testing. METHODS: Using an optical bench set-up, an aspheric monofocal (CT ASPHINA 409M; Carl Zeiss Meditec, Jena, Germany), an aspheric diffractive bifocal (AT LISA 809M; Carl Zeiss Meditec), and an aspheric diffractive trifocal (AT LISA 839M; Carl Zeiss Meditec) intraocular lens (IOL) were evaluated, each with the same distance power, body design, and material. Modulation transfer function (MTF) values were measured at spatial frequencies of 50 lp/mm and aperture sizes of 3 and 4.5 mm. Each IOL was measured while centered, then decentered by 0.25, 0.5, 0.75, and 1 mm. RESULTS: MTF values for the monofocal IOL at far focus with 3- and 4.5-mm aperture size were 0.80/0.80 with maximum reduction to 0.77/0.73 for 1-mm decentration, respectively. Centered IOL MTFs of the bifocal and trifocal IOLs were lower for the far focus at 0.46/0.41 and 0.39/0.26, with reduction at 1-mm decentration to 0.35/0.25 and 0.25/0.18, respectively. Values for near focus of the bifocal and trifocal IOLs reduced from 0.27/0.31 and 0.19/0.18 to 0.2/0.21 and 0.12/0.13, respectively. The trifocal intermediate focus MTF reduced from 0.15/0.10 to 0.12/0.08. MTF values of all three lenses decreased significantly under all conditions with decentration of 0.5 to 0.75 mm. CONCLUSIONS: Monofocal lenses were least negatively affected by decentration, with mean optical quality reduction of less than 10% for 1-mm decentration at physiological pupil sizes. For diffractive bifocal and trifocal lenses, optical quality at all distances was significantly reduced if decentration exceeded 0.75 mm, with intermediate focus showing the least reduction. [J Refract Surg. 2017;33(12):808-812.].
[Mh] Termos MeSH primário: Migração do Implante de Lente Intraocular/fisiopatologia
Iris/anatomia & histologia
Lentes Intraoculares
Óptica e Fotônica
Pseudofacia/fisiopatologia
Pupila/fisiologia
Refração Ocular/fisiologia
[Mh] Termos MeSH secundário: Seres Humanos
Modelos Teóricos
Desenho de Prótese
Visão Ocular
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180223
[Lr] Data última revisão:
180223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171212
[St] Status:MEDLINE
[do] DOI:10.3928/1081597X-20171004-02


  6 / 14507 MEDLINE  
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[PMID]:29227506
[Au] Autor:Ferreira TB; Ribeiro P; Ribeiro FJ; O'Neill JG
[Ti] Título:Comparison of Methodologies Using Estimated or Measured Values of Total Corneal Astigmatism for Toric Intraocular Lens Power Calculation.
[So] Source:J Refract Surg;33(12):794-800, 2017 Dec 01.
[Is] ISSN:1081-597X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To compare the prediction error in the calculation of toric intraocular lenses (IOLs) associated with methods that estimate the power of the posterior corneal surface (ie, Barrett toric calculator and Abulafia-Koch formula) with that of methods that consider real measures obtained using Scheimpflug imaging: a software that uses vectorial calculation (Panacea toric calculator: http://www.panaceaiolandtoriccalculator.com) and a ray tracing software (PhacoOptics, Aarhus Nord, Denmark). METHODS: In 107 eyes of 107 patients undergoing cataract surgery with toric IOL implantation (Acrysof IQ Toric; Alcon Laboratories, Inc., Fort Worth, TX), predicted residual astigmatism by each calculation method was compared with manifest refractive astigmatism. Prediction error in residual astigmatism was calculated using vector analysis. RESULTS: All calculation methods resulted in overcorrection of with-the-rule astigmatism and undercorrection of against-the-rule astigmatism. Both estimation methods resulted in lower mean and centroid astigmatic prediction errors, and a larger number of eyes within 0.50 diopters (D) of absolute prediction error than methods considering real measures (P < .001). Centroid prediction error (CPE) was 0.07 D at 172° for the Barrett toric calculator and 0.13 D at 174° for the Abulafia-Koch formula (combined with Holladay calculator). For methods using real posterior corneal surface measurements, CPE was 0.25 D at 173° for the Panacea calculator and 0.29 D at 171° for the ray tracing software. CONCLUSIONS: The Barrett toric calculator and Abulafia-Koch formula yielded the lowest astigmatic prediction errors. Directly evaluating total corneal power for toric IOL calculation was not superior to estimating it. [J Refract Surg. 2017;33(12):794-800.].
[Mh] Termos MeSH primário: Astigmatismo/diagnóstico
Córnea/patologia
Implante de Lente Intraocular
Lentes Intraoculares
Óptica e Fotônica/métodos
[Mh] Termos MeSH secundário: Adulto
Idoso
Idoso de 80 Anos ou mais
Biometria/métodos
Topografia da Córnea
Feminino
Seres Humanos
Masculino
Meia-Idade
Nomogramas
Facoemulsificação
Refração Ocular/fisiologia
Estudos Retrospectivos
Acuidade Visual/fisiologia
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180223
[Lr] Data última revisão:
180223
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171212
[St] Status:MEDLINE
[do] DOI:10.3928/1081597X-20171004-03


  7 / 14507 MEDLINE  
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[PMID]:29342178
[Au] Autor:Ma J; Zhou P; Ahmad B; Ren G; Wang C
[Ad] Endereço:School of Science, Chongqing University of Posts and Telecommunications, Chongqing, China.
[Ti] Título:Chaos and multi-scroll attractors in RCL-shunted junction coupled Jerk circuit connected by memristor.
[So] Source:PLoS One;13(1):e0191120, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In this paper, a new four-variable dynamical system is proposed to set chaotic circuit composed of memristor and Josephson junction, and the dependence of chaotic behaviors on nonlinearity is investigated. A magnetic flux-controlled memristor is used to couple with the RCL-shunted junction circuit, and the dynamical behaviors can be modulated by changing the coupling intensity between the memristor and the RCL-shunted junction. Bifurcation diagram and Lyapunov exponent are calculated to confirm the emergence of chaos in the improved dynamical system. The outputs and dynamical behaviors can be controlled by the initial setting and external stimulus as well. As a result, chaos can be suppressed and spiking occurs in the sampled outputs under negative feedback, while applying positive feedback type via memristor can be effective to trigger chaos. Furthermore, it is found that the number of multi-attractors in the Jerk circuit can be modulated when memristor coupling is applied on the circuit. These results indicate that memristor coupling can be effective to control chaotic circuits and it is also useful to reproduce dynamical behaviors for neuronal activities.
[Mh] Termos MeSH primário: Iluminação
Retina/anatomia & histologia
Células Fotorreceptoras Retinianas Cones
[Mh] Termos MeSH secundário: Adulto
Seres Humanos
Meia-Idade
Óptica e Fotônica
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180215
[Lr] Data última revisão:
180215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180118
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191120


  8 / 14507 MEDLINE  
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[PMID]:29338027
[Au] Autor:Legras R; Gaudric A; Woog K
[Ad] Endereço:Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Paris-Saclay, Université Paris-Saclay, Orsay, France.
[Ti] Título:Distribution of cone density, spacing and arrangement in adult healthy retinas with adaptive optics flood illumination.
[So] Source:PLoS One;13(1):e0191141, 2018.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The aim of this article is to analyse cone density, spacing and arrangement using an adaptive optics flood illumination retina camera (rtx1™) on a healthy population. Cone density, cone spacing and packing arrangements were measured on the right retinas of 109 subjects at 2°, 3°, 4°, 5° and 6° of eccentricity along 4 meridians. The effects of eccentricity, meridian, axial length, spherical equivalent, gender and age were evaluated. Cone density decreased on average from 28 884 ± 3 692 cones/mm2, at 2° of eccentricity, to 15 843 ± 1 598 cones/mm2 at 6°. A strong inter-individual variation, especially at 2°, was observed. No important difference of cone density was observed between the nasal and temporal meridians or between the superior and inferior meridians. However, the horizontal and vertical meridians differed by around 14% (T-test, p<0.0001). Cone density, expressed in units of area, decreased as a function of axial length (r2 = 0.60), but remained constant (r2 = 0.05) when cone density is expressed in terms of visual angle supporting the hypothesis that the retina is stretched during the elongation of the eyeball. Gender did not modify the cone distribution. Cone density was slightly modified by age but only at 2°. The older group showed a smaller density (7%). Cone spacing increased from 6,49 ± 0,42 µm to 8,72 ± 0,45 µm respectively between 2° and 6° of eccentricity. The mosaic of the retina is mainly triangularly arranged (i.e. cells with 5 to 7 neighbors) from 2° to 6°. Around half of the cells had 6 neighbors.
[Mh] Termos MeSH primário: Luz
Retina/anatomia & histologia
Células Fotorreceptoras Retinianas Cones
[Mh] Termos MeSH secundário: Adolescente
Adulto
Feminino
Seres Humanos
Masculino
Meia-Idade
Óptica e Fotônica
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180215
[Lr] Data última revisão:
180215
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180117
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0191141


  9 / 14507 MEDLINE  
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[PMID]:27774618
[Au] Autor:Aldaba M; Otero C; Pujol J; Atchison DA
[Ad] Endereço:Davalor Research Center (DRC), Universitat Politècnica de Catalunya, Terrassa, Spain.
[Ti] Título:Does the Badal optometer stimulate accommodation accurately?
[So] Source:Ophthalmic Physiol Opt;37(1):88-95, 2017 01.
[Is] ISSN:1475-1313
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:PURPOSE: To study whether the accommodation response to Badal optometer is equivalent to the response for real space targets. METHODS: Accommodative responses were measured for 28 young eyes with the WAM-5500 autorefractometer in eight configurations for 0.17 D, 2.0 D and 5.0 D accommodation stimuli. Parameters that might contribute to differences in response were systematically isolated: stimulation method (real space vs Badal targets), field of view, instrument's cover proximity, the looming effect, and the peripheral interposition of objects in depth. RESULTS: Mean accommodative response differences between a natural view configuration and a configuration with a Badal Optometer were 0.50 ± 0.43 D and 0.58 ± 0.53 D for 2.0 D and 5.0 D stimulation, respectively (p < 0.001), with accommodation lags for the latter condition. Of the isolated parameters that might contribute to these differences, varying the interposition of objects in depth affected accommodation response more markedly. CONCLUSIONS: It is likely that Badal optometers affect accommodation through a combination of some or all of the studied parameters. We conclude that accommodation response to closed-view Badal optometers is not equivalent to real space target response.
[Mh] Termos MeSH primário: Acomodação Ocular/fisiologia
Óptica e Fotônica
Optometria/instrumentação
[Mh] Termos MeSH secundário: Adolescente
Adulto
Feminino
Seres Humanos
Masculino
Matemática
Reprodutibilidade dos Testes
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1707
[Cu] Atualização por classe:180109
[Lr] Data última revisão:
180109
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE
[do] DOI:10.1111/opo.12334


  10 / 14507 MEDLINE  
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[PMID]:29208808
[Au] Autor:Siddiqui AA; Devgan U
[Ad] Endereço:Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
[Ti] Título:Intraocular lens calculations in atypical eyes.
[So] Source:Indian J Ophthalmol;65(12):1289-1293, 2017 Dec.
[Is] ISSN:1998-3689
[Cp] País de publicação:India
[La] Idioma:eng
[Ab] Resumo:Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL) calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.
[Mh] Termos MeSH primário: Biometria/métodos
Lentes Intraoculares
Óptica e Fotônica
Erros de Refração/fisiopatologia
[Mh] Termos MeSH secundário: Seres Humanos
Testes Visuais
Acuidade Visual
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1712
[Cu] Atualização por classe:180103
[Lr] Data última revisão:
180103
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171207
[St] Status:MEDLINE
[do] DOI:10.4103/ijo.IJO_834_17



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