How to Tailor Structural Colors for Extended Visibility and White Light Generation Employing Direct Laser Interference Patterning

The appearance of a surface can be controlled by creating periodic microstructures designed to diffract light and produce structural colors. Nevertheless, since structural coloration is based on diffraction, the produced colors have a strong dependence on the viewing angle and absence of coloration takes place while tilting the samples. In this work direct laser interference patterning is used to firstly provide transparent polymer sheets a structural coloration with a high‐range observation angle, and secondly to demonstrate the combination of structural colors, producing a white coloring effect. The employed approaches are based on the fabrication of micro‐gratings with multiple periods in the same structured area and on the engineering of the diffraction orders of the diffraction spectrum. The patterned surfaces are characterized by confocal microscopy and angular spectrometry in reflection mode. The morphological characterization shows homogeneous surface patterns, while the spectral results demonstrate that combining four spatial periods on a single patterned surface, a white appearance is obtained over an angular observation range higher than 30°. The experimental results are supported by theoretical predictions by means of generalized formulas based on the diffraction of light.     

One step forward,two steps back: Tensions between malaria elimination and improved malaria surveillance in the Solomon Islands

The Solomon Islands experienced, between 2010, an apparent meteoric fall in the level of malaria incidence and prevalence [1]. Thanks ostensibly to the efforts of bilateral and multilateral partners and donors, annual parasite incidence (API) fell from 70 to 40 per 1,000 population. With such dramatic progress, international efforts were hailed as dramatic successes and showcased as progress towards malaria elimination and eradication, Yet, paradoxically, the true caseload of malaria in the Solomon Islands has revealed a situation that calls for more, rather than less, support.     

Influence of surface properties of resin‐based composites on in vitro Streptococcus mutans biofilm development

The aim of this in vitro study was to evaluate the influence of physicochemical surface properties of resin‐based composites on Streptococcus mutans biofilm formation. Specimens were prepared from each of four resin‐based composites by polymerization against Mylar strips. Half of the number of specimens received no further surface treatment, whereas the other half were subjected to a polishing treatment. Surface roughness (SR) and topography were assessed using profilometry and atomic force microscopy. Surface free‐energy (SFE) was determined, and the chemical surface composition was analysed by X‐ray photoelectron spectroscopy (XPS). S. mutans biofilms were formed on the surface of the resin‐based composite specimens for either 48 or 96 h using an artificial mouth system (AMS). Polishing caused a significant decrease in SFE, and XPS analysis indicated an increase of surface silicon and a decrease of surface carbon. Only for Grandio was a significant increase in SR identified after polishing, which was probably related to the higher concentration of filler particles on its surface. Significantly less S. mutans biofilm formation was observed on polished resin‐based composites than on unpolished resin‐based composites. These results indicate that the proportions of resin matrix and filler particles on the surface of resin‐based composites strongly influence S. mutans biofilm formation in vitro, suggesting that minimization of resin matrix exposure might be useful to reduce biofilm formation on the surface of resin‐based composites.     

Gonadal function recovery in very long-term male survivors of childhood cancer

BackgroundAlthough gonadal toxicity has been reported, no data are available on recovery of gonadal function in very long-term survivors of childhood cancer. Inhibin B is a novel reliable serum marker which has been shown to be of value in childhood cancer survivor studies to identify risk groups for impaired gonadal function, but consecutive long-term follow-up studies using serum inhibin B as a marker are not available.ObjectiveTo evaluate possible recovery of gonadal dysfunction over time in adult male survivors of childhood cancer.MethodsIn this retrospective study, adult male long-term childhood cancer survivors (n = 201) who visited our outpatient late effects clinic were included and we used inhibin B as a surrogate marker for gonadal function.ResultsMedian age at diagnosis was 5.9 years (range 0.0–17.5) and discontinuation of treatment was reached at a median age of 8.2 years (range 0.0–20.8). Inhibin B levels were first measured after a median follow-up time of 15.7 years (range 3.0–37.0). Median interval between the first (T1) and second measurement (T2) was 3.3 years (range 0.7–11.3). Median inhibin B level was 127 ng/L (range 5–366) at T1 and 155 ng/L (range 10–507) at T2. The prediction model suggests that inhibin B levels do not normalise in survivors with a very low Inhibin B level at T1.ConclusionsOur results suggest that recovery of gonadal function is possible even long after discontinuation of treatment. However, this recovery does not seem to occur in survivors who already reached critically low inhibin B levels after discontinuation of treatment.