Repeatability and reproducibility of corneal thickness using SOCT Copernicus HR

Purpose: The aim of this study is to determine the reliability of corneal thickness measurements derived from SOCT Copernicus HR (Fourier domain OCT). Methods: Thirty healthy eyes of 30 subjects were evaluated. One eye of each patient was chosen randomly. Images were obtained of the central (up to 2.0 mm from the corneal apex) and paracentral (2.0 to 4.0 mm) cornea. We assessed corneal thickness (central and paracentral) and epithelium thickness. The intra-observer repeatability data were analysed using the intra-class correlation coefficient (ICC) for a range of 95 per cent within-subject standard deviation (SW) and the within-subject coefficient of variation (CW). The level of agreement by Bland–Altman analysis was also represented for the study of the reproducibility between observers and agreement between methods of measurement (automatic versus manual). Results: The mean value of the central corneal thickness (CCT) was 542.4 ± 30.1 μm (SD). There was a high intra-observer agreement, finding the best result in the central sector with an intra-class correlation coefficient of 0.99, 95 per cent CI (0.989 to 0.997) and the worst, in the minimum corneal thickness, with an intra-class correlation coefficient of 0.672, 95 per cent CI (0.417 to 0.829). Reproducibility between observers was very high. The best result was found in the central sector thickness obtained both manually and automatically with an intra-class correlation coefficient of 0.990 in both cases and the worst result in the maximum corneal thickness with an intra-class correlation coefficient of 0.827. The agreement between measurement methods was also very high with intra-class correlation coefficient greater than 0.91. On the other hand the repeatability and reproducibility for epithelial measurements was poor. Conclusion: Pachymetric mapping with SOCT Copernicus HR was found to be highly repeatable and reproducible. We found that the device lacks an appropriate ergonomic design as proper focusing of the laser beam onto the cornea for anterior segment scanning required that patients were positioned slightly farther away from the machine head-rest than in the setup for retinal imaging

Halloysite and Laponite Hybrid Pigments Synthesis with Copper Chlorophyll

Sustainable and green materials have been studied in dye and pigment productions to reduce their environment impacts from being produced and applied. Although natural dyes are an excellent choice to move from agrowaste, some improvements must be made before they are applied given their poor fastness. One way of improving natural dye properties is their adsorption into nanoclay structures to give hybrid pigments. This work used tubular halloysite and laminar laponite to adsorb and stabilize natural copper chlorophyll. With a statistical design of experiments, we observed interactions between synthesis factors, such as pH, ionic strength, and surfactant or silane modification. Cool hybrid pigments with high TSR (%) values and a wide color range were obtained by using dispersions with only distilled water at room temperature. Successful chlorophyll adsorption on both nanoclay surfaces took place by XRD and DTA analyses. The maximum natural dye absorption for both nanoclay types took place under acid conditions, pH 3–4, and in the presence of mordant. The TSR (%) improved by the silane pH interaction, and halloysite hybrid pigments obtained higher TSR values than the laponite ones. Finally, a wide chromatic green color range was obtained with the surfactant modification in both nanoclays, and the color fastening was also improved in the hybrid pigments application. The samples generated with 10% of hybrid pigments from both nanoclays and an Epoxy bioresin, show higher colorfastness than the sample with the natural chlorophyll, due to the nanoclays–dye interaction and protection.This research was funded by Spanish Ministry of Economy and Competitiveness (project RTI2018-096000-B-100)

Evaluating the Graininess Attribute by Visual Scaling for Coatings with Special-Effect Pigments

[EN] In our society, objects' visual appearance is an essential factor because it allows us to recognize and differentiate one object from another. In different industrial sectors like cosmetics, textiles and automotive, special-effect pigments are largely used to achieve attractive visual features. These pigments provide a color change with viewing and illumination direction, and visually provide texture. Depending on a finish's properties, and also on the viewing and illumination conditions, coatings exhibit sparkle or a graininess-like texture. Currently, not many scientific works on the visual perception of these texture effects can be found in the literature. In addition, choice of experimental method can influence the measurement scale obtained from visual data. For this reason, the purpose of this work was to analyze graininess visual scaling constructed by two different psychophysical methods. The experimental design was based on the rank-order and paired-comparison methods. The data analysis was conducted by following the law of comparative judgments to obtain a visual scale of the graininess attribute to compare it to instrumental data. A good correlation appeared between both magnitudes with a correlation coefficient close to 0.9. Both methods provided useful results with a reasonable correspondence between them, which ensures that data can be considered reliable, while the visual obtained scale can act as a good graininess scale perceived by the human visual system.This research was funded by EMRP, grant number 16NRM08, and by the Ministerio de Ciencia, Innovacion y Universidades, grant number RTI2018-096000-B-I00.Perales, E.; Micó-Vicent, B.; Huraibat, K.; Viqueira, V. (2020). Evaluating the Graininess Attribute by Visual Scaling for Coatings with Special-Effect Pigments. Coatings. 10(4):1-10. https://doi.org/10.3390/coatings10040316S11010

Design of online practical lessons in colorimetry

Applied colorimetry is an important module in the program of the elective subject "Colour Science: industrial applications”. This course is taught in the Optics and Optometry Degree and it has been used as a testing for the application of new teaching and assessment techniques consistent with the new European Higher Education Area. In particular, the main objective was to reduce the attendance to lessons and encourage the individual and collective work of students. The reason for this approach is based on the idea that students are able to work at their own learning pace. Within this dynamic work, we propose online lab practice based on Excel templates that our research group has developed ad-hoc for different aspects of colorimetry, such as conversion to different colour spaces, calculation of perceptual descriptors (hue, saturation, lightness), calculation of colour differences, colour matching dyes, etc. The practice presented in this paper is focused on the learning of colour differences. The session is based on a specific Excel template to compute the colour differences and to plot different graphs with these colour differences defined at different colour spaces: CIE ΔE, CIE ΔE94 and the CIELAB colour space. This template is implemented on a website what works by addressing the student work at a proper and organized way. The aim was to unify all the student work from a website, therefore the student is able to learn in an autonomous and sequential way and in his own pace. To achieve this purpose, all the tools, links and documents are collected for each different proposed activity to achieve guided specific objectives. In the context of educational innovation, this type of website is normally called WebQuest. The design of a WebQuest is established according to the criteria of usability and simplicity. There are great advantages of using WebQuests versus the toolbox “Campus Virtual” available in the University of Alicante. The Campus Virtual is an unfriendly environment for this specific purpose as the activities are organized in different sectors depending on whether the activity is a discussion, an activity, a self-assessment or the download of materials. With this separation, it is more difficult that the student follows an organized sequence. However, our WebQuest provides a more intuitive graphical environment, and besides, all the tasks and resources needed to complete them are grouped and organized according to a linear sequence. In this way, the student guided learning is optimized. Furthermore, with this simplification, the student focuses on learning and not to waste resources. Finally, this tool has a wide set of potential applications: online courses of colorimetry applied for postgraduate students, Open Course Ware, etc

Guías y materiales docentes en Moodle para el programa de postgrado en tecnología de color

Actualmente la medida y gestión de la calidad de color de materiales gonio-aparentes es compleja, pero altamente demandada desde varios sectores industriales, como en automoción. En particular, en los últimos años, ha habido una gran demanda de titulados con una buena formación en Tecnología de Color. Por tal motivo, para satisfacer las competencias demandas por la industria, desde el Grupo de Visión y Color de la Universidad de Alicante, se está trabajando en la articulación de un programa de postgrado que oferte a estudiantes, titulados y no titulados, de una amplia y completa formación en Tecnología de Color. Por tanto, el objetivo principal de este trabajo es la elaboración del diseño curricular y materiales docentes para el programa de postgrado propuesto. En una primera fase, el trabajo se centra en la elaboración de la guía docente de cada una de las asignaturas. La segunda fase se centra en la gestión de los materiales docentes mediante la plataforma Moodle que permitirá el seguimiento por parte del alumno a distancia (b-learning). De esta forma, mediante este programa de postgrado se pretende aportar mayores vías de empleabilidad laboral a unos postgraduados en un sector industrial de gran importancia socio-económica a nivel mundial

Diseño curricular y elaboración de materiales para el programa de postgrado en tecnología de color utilizando la plataforma Moodle

En los últimos años, la investigación realizada por el grupo de Visión y Color nos ha permitido conocer la demanda existente en el mercado laboral de expertos en tecnología y reproducción del color, especialmente relacionado con los materiales gonio-aparentes, materiales que ofrecen atractivos atributos para el sector del automóvil, entre otros. Por esta razón, miembros del Grupo de Visión y Color de la Universidad de Alicante nos hemos involucrado en esta red cuyo objetivo principal es ofrecer un programa de postgrado para titulados y no titulados, con una amplia y completa formación en Tecnología de Color. En particular, esta red se ha centrado en el diseño curricular y la elaboración de materiales docentes para este programa de postgrado. En primer lugar, se han desarrollado las guías docentes de cada una de las asignaturas propuestas con el fin de planificar cada una de ellas y poder desarrollar los materiales docentes adecuados. Dado las características de este programa de postgrado, todos los materiales se han elaborado en la plataforma Moodle ya que permite el seguimiento por parte del alumno a distancia (b-learning)

Visual and instrumental correlation of sparkle by the magnitude estimation method

Most real surfaces and objects show variations in appearance with viewing and illumination directions. Besides angular dependency, they also show spatial variation in color, i.e., they exhibit some sort of texture. Of the surfaces we see, surfaces colored by special-effect pigments produce several complex visual effects, like change in color and lightness with viewing and illumination angles, and effects like sparkle and gloss on other textures. In the last two decades, different commercial devices have appeared to help ensure the proper characterization of materials with special-effect pigments. However, the instrumental characterization of sparkle is currently available only by a commercial device integrated into a multi-angle spectrophotometer. As it is difficult to find complete open original studies about the sparkle effect for designing and calibrating this commercial instrument, the main objective of this work was to check whether a good visual and instrumental correlation exists between the sparkle that the observer perceives and the sparkle value provided by the device using some subsets of goniochromatic samples with different types of special-effect pigments and colors. Visual assessments were made by a conventional magnitude estimation method in a directional lighting booth, which belonged to the same company owner of the sparkle instrument, in different geometries and at distinct illuminance levels. The results revealed that there was a good visual correlation of the sparkle grade value. By separately analyzing the factors used in its instrument algorithm, such as sparkle intensity and sparkle area values, it was clearly shown that the correlation was not good or simply did not exist. Consequently, and perhaps in regards to the choice of new special-effect pigments, such as synthetic mica and other future ones, we generated herein even more questions about current mathematical algorithms, and only recognized calculating this texture effect at the industrial level.The authors are grateful to the EMRP for funding the project “Multidimensional Reflectometry for Industry”. The EMRP is jointly funded by EMRP participating countries within EURAMET and the European Union. We thank the Spanish Ministry of Economy and Competitiveness for the coordinated project DPI2011-30090-C02 and project DPI-2015-68514 and University of Alicante for project GRE13-28. Omar Gómez Lozano would also like to thank the above-cited ministry for his pre-doctoral fellowship (FPI BES-2012-053080)

Strategies for continuous improvement in the master's degree in "Colour Technology for the automotive sector" based on feedback from graduates

[ES] The first edition of the Master's Degree in "Color Technology for the Automotive Sector" was held during the last academic year. The academic results in terms of qualifications, achievement and learning were good. In spite of the good sensations, there are aspects to be improved, both in methodology and the development of the subjects, timing of the contents, organization or communication channels. Following this line, the Academic, agreed on a plan of continuous improvement based on the feedback provided by the graduate surveys. A specific survey was carried out to gather their specific experience of the course in order to be able to modify the general strategy of the master's degree at the teaching and organisational level. The objectives were to adapt the teaching methodology to facilitate a more reflexive, participative and autonomous learning with a high degree of involvement and motivation of the students, to improve the academic results in terms of learning and satisfaction, to simplify and improve the logistic management of the course, etc. Thus, the survey included questions relating to the usefulness of the master's degree, methodology, organisation and planning of teaching, as well as a final question relating to the overall satisfaction of the course. A short survey was chosen with only 10 questions that the student rated from 1 to 5 on a scale from "strongly disagree" to "strongly agree". From the analysis of the responses, some important weaknesses were detected, such as the lack of content developed in video format, and the slowness of feedback on the results obtained in the proposed tasks. Based on these results, it was proposed an improvement plan that included the incorporation of videos to teaching materials, flexibility in the deadlines for activities, and the periodic monitoring of student learning and concerns through "Adobe Connect".Perales, E.; Micó-Vicent, B.; Viqueira, V.; Huraibat, K.; Martínez-Verdú, FM. (2019). Strategies for continuous improvement in the master's degree in "Colour Technology for the automotive sector" based on feedback from graduates. En INNODOCT/18. International Conference on Innovation, Documentation and Education. Editorial Universitat Politècnica de València. 165-174. https://doi.org/10.4995/INN2018.2018.8846OCS16517

Changes in contrast sensitivity for aged users of tinted sunglasses

Hoy en día es cada vez más habitual el uso de filtros solares coloreados en un gran número de actividades, tanto de ocio como en el trabajo, al aire libre o en ambientes cerrados. Nos hemos planteado si es recomendable el uso de lentes con cromaticidades diferentes y si esa recomendación sería dependiente del grupo de edad del sujeto.Tinted lenses are increasingly used in many activities, both during leisure time and for work, out in the open and indoors. Our aim is to test if any tinted lens is more advisable than another, and if the choice of colour depends on the age group.Esta investigación se ha llevado a cabo en el marco del proyecto de la Generalitat Valenciana GV06/185

Using Laminar Nanoclays for Phycocyanin and Phycoerythrin Stabilization as New Natural Hybrid Pigments from Microalgae Extraction

C-Phycocyanin (PC) and B-phycoerythrin (PE) are light-harvesting water-soluble phycobiliproteins from microalgae that belong mainly to the cyanobaceria and rhodhophytes families. Different methods have been developed for PC and PE extraction and purification from microalgae, and offer a high potential for their use as additives in sectors such as food and cosmetics. However, the main limitations of using these dyes are the sensitivity of their environmental factors, such as light fastness, temperature, and pH. We successfully employed safe lamellar nanoclays such as montmorillonite (M) and Laponite (L) for phycobiliproteins stabilization, as we did before with other natural dyes. We obtained a wide color gamut from blues to pink by combining four different factors under synthesis conditions: three dye concentrations; two laminar nanoclay sizes; a two nanoclay surface modifiers combination with cetylpyridinium bromide (CPB) and a coupling agent (3-Aminopropyl) triethoxysilane. The experimental conditions were defined according to a multilevel factorial design of experiment (DOE) to study the factors interacting in the final hybrid pigment characteristics. In both M and L, the d001 distance (nm) increased due to PC and PE adsorption. The best conditions to increase the basal space depend on the nanoclay structure, and it is better to use the surfactant for M, and silane modification for L. In addition, optical and thermal PE and PC properties significantly improved. We show the optimal synthesis conditions to increase PC and PE adsorption using the high dye concentration, with surfactant and silane depending on the nanoclay. The hybrid pigments from these phycobiliproteins offer the opportunity to perform several industrial applications, including in polymer additives, cosmetics, and packaging.This research was funded by Spanish Ministry of Economy and Competitiveness (Project RTI2018-096000-B-100)