Light scattering and color adaptation that originate from a natural nanomaterial

Color is ubiquitous in nature; however, the ability to rapidly change color in response to environmental cues is unique to few biological systems. Cephalopods, including squid, octopus, and cuttlefish, are one such system; they use sophisticated optical organs that assist in color adaptation in different environments. While several attempts have been made to explore, understand, and exploit the adaptive coloration of cephalopods for materials applications, much of the progress to date has relied on modeling with assumptions that all light not reflected or transmitted is absorbed, which ignores the contribution of light scattering in the skin. We believe that scattering plays a significant role in color perception and should be included in discussions of new colors and color-changing materials. We argue that both forward and backward scattering must be accounted for in the optical analysis of a sample; otherwise, an incorrect absorption spectrum and resulting color analysis may be deduced from the experimental data. To test these hypotheses, we fabricated films comprising a distribution of bio-derived pigmented nanoparticles with multiple thicknesses. To achieve these different thicknesses, we casted a suspension (0.16 - 2.45 mg/ml) of nanoparticles which were first isolated and purified from squid Doryteuthis pealeii skin onto functionalized surfaces. We chose squid particles in our model system due to their unique refractive index (n =1.92) and ability to potentiate color change via translocation in the skin. The color quality and consistency of the films were measured using the International Commission on Illumination (CIE) tristimulus values. We observed that that both color and brightness in mimetic films could be controlled by varying particle layer thicknesses and by combining a back-reflector with a specific band pass, illustrating new materials applications for these biological nanostructures. Diffuse and specular scattering of the granules was also measured using experimental and theoretical approaches. We observed that the squid-derived pigments not only provide rich color but they can also scatter attenuated light. Combined, these characteristics make such bio-derived materials interesting candidates for future topical materials such as cosmetics and coatings designed to provide color or color-matching to a specific environment

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Optical extinction of size-controlled aerosols generated from squid chromatophore pigments

Nanophotonic granules populate the interior of cephalopod chromatophores, contributing to their visible color by selectively absorbing and scattering light. Inspired by the performance of these granules, we fabricated nanostructured aerosols by nebulizing a pigment solution extracted from native squid chromatophores. We determined their optical extinction using cavity ring-down spectroscopy and show how extinction cross section is dependent on both particle concentration and size. This work not only advances the fundamental knowledge of the optical properties of chromatophore pigments but also serves as a proof-of-concept method that can be adapted to develop coatings derived from these pigmentary aerosols

A new paradigm of electrical stimulation to enhance sensory neural function

The ability to improve peripheral neural transmission would have significant therapeutic potential in medicine. A technology of this kind could be used to restore and/or enhance sensory function in individuals with depressed sensory function, such as older adults or patients with peripheral neuropathies. The goal of this study was to investigate if a new paradigm of subsensory electrical noise stimulation enhances somatosensory function. Vibration (50. Hz) was applied with a Neurothesiometer to the plantar aspect of the foot in the presence or absence of subsensory electrical noise (1/f type). The noise was applied at a proximal site, on a defined region of the tibial nerve path above the ankle. Vibration perception thresholds (VPT) of younger adults were measured in control and experimental conditions, in the absence or presence of noise respectively. An improvement of ~16% in VPT was found in the presence of noise. These are the first data to demonstrate that modulation of axonal transmission with externally applied electrical noise improves perception of tactile stimuli in humans

Contributions of Phenoxazone-Based Pigments to the Structure and Function of Nanostructured Granules in Squid Chromatophores

Understanding the structure–function relationships of pigment-based nanostructures can provide insight into the molecular mechanisms behind biological signaling, camouflage, or communication experienced in many species. In squid Doryteuthis pealeii, combinations of phenoxazone-based pigments are identified as the source of visible color within the nanostructured granules that populate dermal chromatophore organs. In the absence of the pigments, granules experience a reduction in diameter with the loss of visible color, suggesting important structural and functional features. Energy gaps are estimated from electronic absorption spectra, revealing highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energies that are dependent upon the varying carboxylated states of the pigment. These results implicate a hierarchical mechanism for the bulk coloration in cephalopods originating from the molecular components confined within in the nanostructured granules of chromatophore organs

Cost effectiveness of group follow-up after structured education for type 1 diabetes:A cluster randomised controlled trial

Background: This study examines the cost effectiveness of group follow-up after participation in the Dose Adjustment for Normal Eating (DAFNE) structured education programme for type 1 diabetes. Methods: Economic evaluation conducted alongside a cluster randomised controlled trial involving 437 adults with type 1 diabetes in Ireland. Group follow-up involved two group education 'booster' sessions post-DAFNE. Individual follow-up involved two standard one-to-one hospital clinic visits. Incremental costs, quality-adjusted life years (QALYs) gained and cost effectiveness were estimated at 18 months. Uncertainty was explored using sensitivity analysis and by estimating cost effectiveness acceptability curves. Results: Group follow-up was associated with a mean reduction in QALYs gained of 0.04 per patient (P value, 0.052; 95% CI, -0.08 to 0.01, intra-class correlation (ICC), 0.033) and a mean reduction in total healthcare costs of is an element of 772 (P value, 0.020; 95% CI, -1,415 to -128: ICC, 0.016) per patient. At alternative threshold values of is an element of 5,000, is an element of 15,000, is an element of 25,000, is an element of 35,000, and is an element of 45,000, the probability of group follow-up being cost effective was estimated to be 1.000, 0.762, 0.204, 0.078, and 0.033 respectively. Conclusions: The results do not support implementation of group follow-up as the sole means of follow-up post-DAFNE. Given the reported cost savings, future studies should explore the cost effectiveness of alternative models of group care for diabetes