Adaptive optics in the mouse eye: wavefront sensing based vs. image-guided aberration correction

Adaptive Optics (AO) is required to achieve diffraction limited resolution in many real-life imaging applications in biology and medicine. AO is essential to guarantee high fidelity visualization of cellular structures for retinal imaging by correcting ocular aberrations. Aberration correction for mouse retinal imaging by direct wavefront measurement has been demonstrated with great success. However, for mouse eyes, the performance of the wavefront sensor (WFS) based AO can be limited by several factors including non-common path errors, wavefront reconstruction errors. and an ill-defined reference plane. Image-based AO can avoid these issues at the cost of algorithmic execution time. Furthermore, image-based approaches can provide improvements to compactness, accessibility, and even the performance of AO systems. Here, we demonstrate the ability of image-based AO to provide comparable aberration correction and image resolution to the conventional Shack-Hartmann WFS-based AO approach. The residual wavefront error of the mouse eye was monitored during a wavefront sensorless optimization to allow comparison with classical AO. This also allowed us to improve the performance of our AO system for small animal retinal imaging. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen

Effect of a contact lens on mouse retinal in vivo imaging: Effective focal length changes and monochromatic aberrations

For in vivo mouse retinal imaging, especially with Adaptive Optics instruments, application of a contact lens is desirable, as it allows maintenance of cornea hydration and helps to prevent cataract formation during lengthy imaging sessions. However, since the refractive elements of the eye (cornea and lens) serve as the objective for most in vivo retinal imaging systems, the use of a contact lens, even with 0 Dpt. refractive power, can alter the system's optical properties. In this investigation we examined the effective focal length change and the aberrations that arise from use of a contact lens. First, focal length changes were simulated with a Zemax mouse eye model. Then ocular aberrations with and without a 0 Dpt. contact lens were measured with a Shack-Hartmann wavefront sensor (SHWS) in a customized AO-SLO system. Total RMS wavefront errors were measured for two groups of mice (14-month, and 2.5-month-old), decomposed into 66 Zernike aberration terms, and compared. These data revealed that vertical coma and spherical aberrations were increased with use of a contact lens in our system. Based on the ocular wavefront data we evaluated the effect of the contact lens on the imaging system performance as a function of the pupil size. Both RMS error and Strehl ratios were quantified for the two groups of mice, with and without contact lenses, and for different input beam sizes. These results provide information for determining optimum pupil size for retinal imaging without adaptive optics, and raise critical issues for design of mouse optical imaging systems that incorporate contact lenses

Fast stabilization of a high-energy ultrafast OPA with adaptive lenses

The use of fast closed-loop adaptive optics has improved the performance of optical systems since its first application. Here we demonstrate the amplitude and carrier-envelope phase stabilization of a high energy IR optical parametric amplifier devoted to Attosecond Science exploiting two high speed adaptive optical systems for the correction of static and dynamic instabilities. The exploitation of multi actuator adaptive lenses allowed for a minimal impact on the optical setup

Functional properties of sodium and calcium caseinate antimicrobial active films containing carvacrol

Active edible films were prepared by adding carvacrol into sodium caseinate (SC) and calcium caseinate (CC) matrices plasticized with two different glycerol concentrations (25 and 35 wt%) prepared by solvent casting. Functional characterisation of these bio-films was carried out by determination of some of their physico-chemical properties, such as colour, transparency, oxygen barrier, wettability, dye permeation properties and antibacterial effectiveness against Gram negative and Gram positive bacteria. All films exhibited good performance in terms of optical properties in the CIELab space showing high transparency. Carvacrol was able to reduce CC oxygen permeability and slightly increased the surface hydrophobicity. Dye diffusion experiments were performed to evaluate permeation properties. The diffusion of dye through films revealed that SC was more permeable than CC. The agar diffusion method was used for the evaluation of the films antimicrobial effectiveness against Escherichia cell and Staphylococcus aureus. Both SC and CC edible films with carvacrol showed inhibitory effects on both bacteria. (C) 2013 Elsevier Ltd. All rights reserved.This research was supported by the Ministry of Science and Innovation of Spain through the projects MAT2011-28468-C02-01, MAT2011-28468-C02-02 and HP2008-0080. M.P. Arrieta thanks Fundacion MAPFRE for "Ignacio Hernando de Larramendi 2009-Medio Ambiente" fellowship (MAPFRE-IHL-01). Authors thank Ferrer Alimentacion S.A., for providing the caseinates powders.Arrieta, MP.; Peltzer, MA.; López Martínez, J.; Garrigós Selva, MDC.; Valente, AJM.; Jimenez Migallon, A. (2014). Functional properties of sodium and calcium caseinate antimicrobial active films containing carvacrol. Journal of Food Engineering. 121:94-101. https://doi.org/10.1016/j.jfoodeng.2013.08.015S9410112

Structure and mechanical properties of sodium and calcium caseinate edible active films with carvacrol

Edible active films based on sodium caseinate (SC) and calcium caseinate (CC) plasticized with glycerol (G) at three different concentrations and carvacrol (CRV) as active agent were prepared by solvent casting. Transparent films were obtained and their surfaces were analysed by optical microscopy and scanning electron microscopy (SEM). The influence of the addition of three different plasticizer concentrations was studied by determining tensile properties, while Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to evaluate the structural and thermal behavior of such films. The addition of glycerol resulted in a reduction in the elastic modulus and tensile strength, while some increase in the elongation at break was observed. In general terms, SC films showed flexibility higher than the corresponding CC counterparts. In addition, the presence of carvacrol caused further improvements in ductile properties suggesting the presence of stronger interactions between the protein matrix and glycerol, as it was also observed in thermal degradation studies. FTIR spectra of all films showed the characteristic bands and peaks corresponding to proteins as well as to primary and secondary alcohols. In summary, the best results regarding mechanical and structural properties for caseinates-based films containing carvacrol were found for the formulations with high glycerol concentrations.Marina Patricia Arrieta thanks Fundacion MAPFRE for "Ignacio Hernando de Larramendi 2009- Medio Ambiente" fellowship (MAPFRE-IHL-01). The Spanish Ministry of Economy and Competitiveness is acknowledged by financial support (project Ref. MAT2011-28468-C02-01). Authors thank to Ferrer Alimentacion S.A., for providing caseinates and to Prof. Juan Lopez Martinez (Polytechnic University of Valencia, Spain) for his collaboration and useful discussions.Arrieta, MP.; Peltzer, MA.; Garrigós, MDC.; Jimenez, A. (2013). Structure and mechanical properties of sodium and calcium caseinate edible active films with carvacrol. Journal of Food Engineering. 114(4):486-494. https://doi.org/10.1016/j.jfoodeng.2012.09.002S486494114