ABSTRACT.Purpose: To compile a multicenter normative database of retinal nerve fibre layer (RNFL) and macular thicknesses and macular volume values in healthy Caucasian children 4-17 years using spectral-domain optical coherence tomography (SD-OCT). To analyse variations in the OCT measurements as a function of age, sex, refraction, and axial length (AL).Methods: An observational, multicenter and cross-sectional study among 301 healthy Caucasian children recruited at three Spanish centres was performed. To compile the database, each child underwent a dilated eye examination and a cycloplegic refraction, five AL measurements (IOL Master; Carl Zeiss Meditec, Dublin, CA, USA), five OCT scans with Cirrus OCT: three peripapillary RNFL scans (Optic Disc Cube 200X200 protocol) and two macular scans (Macular Cube 512X128 protocol). One eye of each subject was selected randomly for analysis.Results: Two hundred eighty-three children (117 boys, 41.34%; 166 girls, 58.66%) were included in this study. The mean age of the children was 9.58 ± 3.12 years (range, 4-17). The mean SE was +0.63 ± 1.65 D; (range, )4.88 to +5.25). The mean AL was 22.94 ± 1.10 mm (range, 20.10-26.27). The mean global RNFL thickness was 97.40 ± 9.0 lm (range, 77-121.7 lm). Multivariate analysis showed a positive correlation between the RNFL and spherical equivalent (SE) (p = 0.014). The mean central macular thickness was 253.85 ± 19.76 lm, the average thickness 283.62 ± 14.08 lm, and the mean macular volume 10.22 ± 0.49 lm 3. Multivariate analysis showed a positive correlation between central macular thickness and age (p < 0.001). Boys had a significantly thicker central macula than girls (p < 0.001).Conclusions: Normative paediatric SD-OCT data might facilitate use of SD-OCT for assessing childhood ophthalmic diseases. This study provides a multicenter paediatric normative database of SD-OCT peripapillary RNFL and macular data.

This paper investigates the sequence of morphological transitions in a nearly hard sphere arrangement confined in a wedge cell. A model that shows smooth transitions between the different particle orderings for a small number of layers is proposed. In this model, both the buckling and the (100) hexagonal close packed (hcp) phases are particular cases of a much more general particle arrangement tendency that we call hcp-like ordering. This phase, which does not correspond to any known close packed ordering, is able to adopt packing arrangements commensurate with the cell thickness. More striking, the hcp-like phase adapts itself to the progressive changes of the cell thickness by a smooth change in the interlayer spacing. We present hcp-like orderings up to six layers and a complete sequence of transformations between two and four layers. Finally, a packing model of the transition from two to three layers is also presented.

This Letter investigates the influence of finite size effects on the particle arrangement of thin film colloidal crystals. A rich variety of crystallographic faceting with large single domain microcrystallites is shown. Optical reflectance experiments together with scanning electron microscopy permit the identification of the crystal symmetry and the facet orientation, as well as the exact number of monolayers. When the cell thickness is not commensurable with a high symmetry layering, particles arrange themselves in a periodic distribution of (111)- and (100)-orientated face centered cubic (fcc) microcrystallites separated by planar defects. These structures can be described as a fcc ordering orientated along a vicinal surface, modified by a periodic distribution of fcc (111) stacking faults.

A sensitive and highly selective enzyme-linked immunosorbent assay was developed for triclosan, one of the most common bactericides in personal care products, which is also considered as an emerging contaminant, given its presence in the effluents of sewage and wastewater treatment plants. From synthesized haptens, polyclonal rabbit antibodies against triclosan were raised. The best ELISA immunoassay was based on an antibody-coated format, yielding a detection limit of 0.03 microg L(-1), an I50 of 3.85 microg L(-1), and a dynamic range from 0.22 to 42.16 microg L(-1), with little or no cross-reactivity (< 10%) to similarly structured compounds, including its metabolite methyltriclosan (CR < 6%). The assay was applied as a screening method to quantify triclosan in surface water and in wastewaters. After C18 solid-phase extraction, nanogram per liter concentrations were determined in effluents of urban wastewater treatment plants. The satisfactory recoveries achieved as well as the agreement between immunochemical and chromatographic methods (GC-MS) indicate its potential for either screening or laboratory quantification.

This paper investigates the sequence of morphological transitions in a nearly hard particle arrangement of colloidal crystals confined in a wedge cell. Earlier studies have shown intermediate particle arrangements (such as the buckling, rhombic, prismatic, and hcp like phases) to account for the drastic changes in the filling fraction values between the triangular and square arrangements. However, to the best of our knowledge, there is no complete description of the transitions between n and n + 1 layers.Here we describe the ordering of the particles for films between 1 and 4 layers. We also present a new intermediate phase hcp(011) to show the transition between n, / nO for n > 2 layers.