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We performed an experiment in a laboratory flume to test the effects of water flow speed and the concentration of aqueaous copper on the feeding behavior, growth rate, and accumulation of copper in the tissues of juvenile polychaetes Polydora cornuta. The experiment included two flow speeds (6 or 15 cm/s) and two concentrations of added copper (0 or 85 μg/L). Worms grew significantly faster in the faster flow and in the lower copper concentration. In the slower flow, the total time worms spent feeding decreased significantly as copper concentration increased, but copper did not significantly affect the time worms spent feeding in the faster flow. Across all treatments, there was a significant, positive relationship between the time individuals spent feeding and their relative growth rate. Worms were observed suspension feeding significantly more often in the faster flow and deposit feeding significantly more often in the slower flow, but copper concentration did not affect the proportion of time spent in either feeding mode. The addition of 85 μg/L copper significantly increased copper accumulation in P. cornuta tissue, but the accumulation did not differ significantly due to flow speed. There was a significant interaction between copper and flow; the magnitude of the difference in copper accumulation between the 0 and 85 μg/L treatments was greater in the faster flow than in the slower flow. In slow flows that favor deposit feeding, worms grow slowly and accumulate less copper in their tissue than in faster flows that favor suspension feeding and faster growth.

Copyright © 2020 The Author(s). Background: Pollution – unwanted waste released to air, water, and land by human activity – is the largest environmental cause of disease in the world today. It is responsible for an estimated nine million premature deaths per year, enormous economic losses, erosion of human capital, and degradation of ecosystems. Ocean pollution is an important, but insufficiently recognized and inadequately controlled component of global pollution. It poses serious threats to human health and well-being. The nature and magnitude of these impacts are only beginning to be understood. Goals: (1) Broadly examine the known and potential impacts of ocean pollution on human health. (2) Inform policy makers, government leaders, international organizations, civil society, and the global public of these threats. (3) Propose priorities for interventions to control and prevent pollution of the seas and safeguard human health. Methods: Topic-focused reviews that examine the effects of ocean pollution on human health, identify gaps in knowledge, project future trends, and offer evidence-based guidance for effective intervention. Environmental Findings: Pollution of the oceans is widespread, worsening, and in most countries poorly controlled. It is a complex mixture of toxic metals, plastics, manufactured chemicals, petroleum, urban and industrial wastes, pesticides, fertilizers, pharmaceutical chemicals, agricultural runoff, and sewage. More than 80% arises from land-based sources. It reaches the oceans through rivers, runoff, atmospheric deposition and direct discharges. It is often heaviest near the coasts and most highly concentrated along the coasts of low- and middle-income countries. Plastic is a rapidly increasing and highly visible component of ocean pollution, and an estimated 10 million metric tons of plastic waste enter the seas each year. Mercury is the metal pollutant of greatest concern in the oceans; it is released from two main sources – coal combustion and small-scale gold mining. Global spread of industrialized agriculture with increasing use of chemical fertilizer leads to extension of Harmful Algal Blooms (HABs) to previously unaffected regions. Chemical pollutants are ubiquitous and contaminate seas and marine organisms from the high Arctic to the abyssal depths. Ecosystem Findings: Ocean pollution has multiple negative impacts on marine ecosystems, and these impacts are exacerbated by global climate change. Petroleum-based pollutants reduce photosynthesis in marine microorganisms that generate oxygen. Increasing absorption of carbon dioxide into the seas causes ocean acidification, which destroys coral reefs, impairs shellfish development, dissolves calcium-containing microorganisms at the base of the marine food web, and increases the toxicity of some pollutants. Plastic pollution threatens marine mammals, fish, and seabirds and accumulates in large mid-ocean gyres. It breaks down into microplastic and nanoplastic particles containing multiple manufactured chemicals that can enter the tissues of marine organisms, including species consumed by humans. Industrial releases, runoff, and sewage increase frequency and severity of HABs, bacterial pollution, and anti-microbial resistance. Pollution and sea surface warming are triggering poleward migration of dangerous pathogens such as the Vibrio species. Industrial discharges, pharmaceutical wastes, pesticides, and sewage contribute to global declines in fish stocks. Human Health Findings: Methylmercury and PCBs are the ocean pollutants whose human health effects are best understood. Exposures of infants in utero to these pollutants through maternal consumption of contaminated seafood can damage developing brains, reduce IQ and increase children’s risks for autism, ADHD and learning disorders. Adult exposures to methylmercury increase risks for cardiovascular disease and dementia. Manufactured chemicals – phthalates, bisphenol A, flame retardants, and perfluorinated chemicals, many of them released into the seas from plastic waste – can disrupt endocrine signaling, reduce male fertility, damage the nervous system, and increase risk of cancer. HABs produce potent toxins that accumulate in fish and shellfish. When ingested, these toxins can cause severe neurological impairment and rapid death. HAB toxins can also become airborne and cause respiratory disease. Pathogenic marine bacteria cause gastrointestinal diseases and deep wound infections. With climate change and increasing pollution, risk is high that Vibrio infections, including cholera, will increase in frequency and extend to new areas. All of the health impacts of ocean pollution fall disproportionately on vulnerable populations in the Global South – environmental injustice on a planetary scale. Conclusions: Ocean pollution is a global problem. It arises from multiple sources and crosses national boundaries. It is the consequence of reckless, shortsighted, and unsustainable exploitation of the earth’s resources. It endangers marine ecosystems. It impedes the production of atmospheric oxygen. Its threats to human health are great and growing, but still incompletely understood. Its economic costs are only beginning to be counted. Ocean pollution can be prevented. Like all forms of pollution, ocean pollution can be controlled by deploying data-driven strategies based on law, policy, technology, and enforcement that target priority pollution sources. Many countries have used these tools to control air and water pollution and are now applying them to ocean pollution. Successes achieved to date demonstrate that broader control is feasible. Heavily polluted harbors have been cleaned, estuaries rejuvenated, and coral reefs restored. Prevention of ocean pollution creates many benefits. It boosts economies, increases tourism, helps restore fisheries, and improves human health and well-being. It advances the Sustainable Development Goals (SDG). These benefits will last for centuries. Recommendations: World leaders who recognize the gravity of ocean pollution, acknowledge its growing dangers, engage civil society and the global public, and take bold, evidence-based action to stop pollution at source will be critical to preventing ocean pollution and safeguarding human health. Prevention of pollution from land-based sources is key. Eliminating coal combustion and banning all uses of mercury will reduce mercury pollution. Bans on single-use plastic and better management of plastic waste reduce plastic pollution. Bans on persistent organic pollutants (POPs) have reduced pollution by PCBs and DDT. Control of industrial discharges, treatment of sewage, and reduced applications of fertilizers have mitigated coastal pollution and are reducing frequency of HABs. National, regional and international marine pollution control programs that are adequately funded and backed by strong enforcement have been shown to be effective. Robust monitoring is essential to track progress. Further interventions that hold great promise include wide-scale transition to renewable fuels; transition to a circular economy that creates little waste and focuses on equity rather than on endless growth; embracing the principles of green chemistry; and building scientific capacity in all countries. Designation of Marine Protected Areas (MPAs) will safeguard critical ecosystems, protect vulnerable fish stocks, and enhance human health and well-being. Creation of MPAs is an important manifestation of national and international commitment to protecting the health of the seas. The Centre Scientifique de Monaco, the Prince Albert II of Monaco Foundation and the Government of the Principality of Monaco John J. Stegeman is supported by U.S. Oceans and Human Health Program (NIH grant P01ES028938 and National Science Foundation grant OCE-1840381). Lora E. Fleming is supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 774567 (H2020 SOPHIE Project) and No 666773 (H2020 BlueHealth Project). Plastic toxicity research for Dimitri Deheyn is supported by the BEST Initiative (https://deheynlab.ucsd.edu/best-2/). Barbara Demeneix is supported by grants from the program H2020. Charles J. Dorman is supported by Science Foundation Ireland Investigator Award 13/IA/1875. William H. Gaze is supported by a Natural Environment Research Council Knowledge Exchange Fellowship NE/S006257/1 on the environmental dimension of antimicrobial resistance. Philippe Grandjean is supported by National Institute of Environmental Health Sciences (NIEHS) of the NIH (grant No. ES027706), a Superfund center grant for the Sources, Transport, Exposure and Effects of Perfluoroalkyl Substances (STEEP) Center. Mark E. Hahn is supported by U.S. Oceans and Human Health Program (NIH grant P01ES028938 and National Science Foundation grant OCE-1840381). Amro Hamdoun is supported by NIH and NSF Program on Oceans and Human Health Grants NIH ES030318 and NSF 1840844. Philipp Hess is supported by the IAEA Core Research Project K41014, by the European H2020 program for funding the EMERTOX project (grant number 778069), by the Atlantic Interreg (grant number Alertox-Net EAPA-317-2016) and by EFSA for the project EUROCIGUA (framework partnership agreement GP/EFSA/AFSCO/2015/03). Rachel T. Noble was supported by the US National Science Foundation Accelerating Innovations in Research #1602023 and the NOAA NERRS Science Collaborative. Maria Luiza Pedrotti is supported by Centre National de la Recherche Scientifique (CNRS). Luigi Vezzulli is supported by the following grants: European FP7 Program Grant AQUAVALENS 311846 and European Union’s Horizon 2020 Research and Innovation Program Grant VIVALDI 678589. Pál Weihe is supported by the Danish EPA programme: Danish Cooperation for Environment in the Arctic and by the Faroese Research Council.

Significance A foundational question in biology is how phenotypically similar traits arise. Here we identify two distinct white pigment cell populations, leucophores, that arise from independent progenitors in zebrafish and its relatives. Remarkably, one of these leucophore populations develops from previously differentiated, black melanophores. These different leucophores exhibited distinct pigment chemistries, cytological features, gene expression profiles, and genetic requirements, and whole-animal experiments implicated these cells in behavioral interactions. Our several approaches provide insights into pigment cell complements and origins in zebrafish and contribute to our understanding of form and function in the spectacular pigment patterns of teleost fishes., Understanding genetic and cellular bases of adult form remains a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells of vertebrates, derived from embryonic neural crest, are a useful system for elucidating mechanisms of fate specification, pattern formation, and how particular phenotypes impact organismal behavior and ecology. In a survey of Danio fishes, including the zebrafish Danio rerio, we identified two populations of white pigment cells—leucophores—one of which arises by transdifferentiation of adult melanophores and another of which develops from a yellow–orange xanthophore or xanthophore-like progenitor. Single-cell transcriptomic, mutational, chemical, and ultrastructural analyses of zebrafish leucophores revealed cell-type–specific chemical compositions, organelle configurations, and genetic requirements. At the organismal level, we identified distinct physiological responses of leucophores during environmental background matching, and we showed that leucophore complement influences behavior. Together, our studies reveal independently arisen pigment cell types and mechanisms of fate acquisition in zebrafish and illustrate how concerted analyses across hierarchical levels can provide insights into phenotypes and their evolution.

We present a procedure for simulating epitaxial growth based on the phase-field method. We consider a basic model in which growth is initiated by a flux of atoms onto a heated surface. The deposited atoms diffuse in the presence of this flux and eventually collide to form islands which grow and decay by the attachment and detachment of migrating atoms at their edges. Our implementation of the phase-field method for this model includes uniform deposition, isotropic surface diffusion, and stochastic nucleation (in both space and time), which creates islands whose boundaries evolve as the surface atoms "condense" into and "evaporate" from the islands. Computations using this model in the submonolayer regime, prior to any appreciable coalescence of islands, agree with the results of kinetic Monte Carlo (KMC) simulations for the coverage-dependence of adatom and island densities and island-size distributions, for both reversible and irreversible growth. The scaling of the island density, as obtained from homogeneous rate equations, agrees with KMC simulations for irreversible growth and for reversible growth for varying deposition flux at constant temperature. For reversible growth with varying temperature but constant flux, agreement relies on an estimate of the formation energy of the critical cluster. Taken together, our results provide a comprehensive analysis of the phase-field method in the submonolayer regime of epitaxial growth, including the verification of the main scaling laws for adatoms and island densities and the scaling functions for island-size distributions, and point to the areas where the method can be extended and improved.

The Markov chain Monte Carlo (MCMC) method is used to evaluate the imaginary-time path integral of a quantum oscillator with a potential that includes both a quadratic term and a quartic term whose coupling is varied by several orders of magnitude. This path integral is discretized on a time lattice and calculations for the energy and probability density of the ground state and energies of the first few excited states are carried out on lattices with decreasing spacing to estimate these quantities in the continuum limit. The variation of the quartic coupling constant produces corresponding variations in the optimum simulation parameters for the MCMC method and in the statistical uncertainty for a fixed number of paths used for measurement. The energies and probability densities are in excellent agreement with those obtained from numerical solutions of Schr\"odinger's equation., Comment: Published in European Journal of Physics

The calculation of phonon dispersion for crystalline solids with r atoms in a unit cell requires solving a 3r-dimensional eigenvalue problem. We propose a simplified approach to lattice dynamics which yields approximate analytical expressions and accurate numerical solutions to phonon dispersion without explicitly solving this eigenvalue problem. This is accomplished by a coordinate transformation to the normal modes of the isolated primitive unit cell, which is extended over the entire crystal by Fourier transformation, so each phonon branch is labelled by the irreducible representations of the symmetry group of the unit cell from which the atomic displacements can be readily identified from standard group theoretic methods. The resulting dynamical matrix is analyzed perturbatively, with the diagonal elements as the zeroth-order matrix and the off-diagonal elements as the perturbation. The zeroth-order matrix provides approximate analytical expressions for the phonon dispersions, the first-order terms vanish, with the higher-order terms converging to the exact solutions. We describe the application of this method to a one-dimensional diatomic chain, graphene, and hexagonal close-packed zirconium. In all cases, the zeroth-order solution provides reasonable approximations, while the second-order solutions already show the rapid convergence to the exact dispersion curves. This methodology provides insight into the lattice dynamics of crystals, molecular solids, and Jahn–Teller systems, while significantly reducing the computational cost. Similarities between our method and other techniques that use local basis sets for calculating electronic and vibrational properties of materials are discussed. We conclude by exploring extensions that widen the scope of our approach.The calculation of phonon dispersion for crystalline solids with r atoms in a unit cell requires solving a 3r-dimensional eigenvalue problem. We propose a simplified approach to lattice dynamics which yields approximate analytical expressions and accurate numerical solutions to phonon dispersion without explicitly solving this eigenvalue problem. This is accomplished by a coordinate transformation to the normal modes of the isolated primitive unit cell, which is extended over the entire crystal by Fourier transformation, so each phonon branch is labelled by the irreducible representations of the symmetry group of the unit cell from which the atomic displacements can be readily identified from standard group theoretic methods. The resulting dynamical matrix is analyzed perturbatively, with the diagonal elements as the zeroth-order matrix and the off-diagonal elements as the perturbation. The zeroth-order mat...

Corals and humans represent two extremely disparate metazoan lineages and are therefore useful for comparative evolutionary studies. Two lipid-based molecules that are central to human immunity, platelet-activating factor (PAF) and Lyso-PAF were recently identified in scleractinian corals. To identify processes in corals that involve these molecules, PAF and Lyso-PAF biosynthesis was quantified in conditions known to stimulate PAF production in mammals (tissue growth and exposure to elevated levels of ultraviolet light) and in conditions unique to corals (competing with neighbouring colonies over benthic space). Similar to observations in mammals, PAF production was higher in regions of active tissue growth and increased when corals were exposed to elevated levels of ultraviolet light. PAF production also increased when corals were attacked by the stinging cells of a neighbouring colony, though only the attacked coral exhibited an increase in PAF. This reaction was observed in adjacent areas of the colony, indicating that this response is coordinated across multiple polyps including those not directly subject to the stress. PAF and Lyso-PAF are involved in coral stress responses that are both shared with mammals and unique to the ecology of cnidarians.

A hybrid solar energy conversion system has been developed for converting sunlight into electricity and thermal energy. The system increases efficiency and reduces cost by utilizing a transmissive, spectrum-splitting concentrator photovoltaic module featuring triple junction III-V solar cells. This enables cell temperatures to be maintained below 100°C while thermal temperatures may rise as high as 600°C. The presentation will discuss module and system design, a series of prototype iterations, and multi-day outdoor field testing. Techno-economic analysis will be presented in a variety of locations and industrial process heat contexts.

We present a path integral formulation of Darcy's equation in one dimension with random permeability described by a correlated multi-variate lognormal distribution. This path integral is evaluated with the Markov chain Monte Carlo method to obtain pressure distributions, which are shown to agree with the solutions of the corresponding stochastic differential equation for Dirichlet and Neumann boundary conditions. The extension of our approach to flow through random media in two and three dimensions is discussed.

Author(s): Yates, KK; Turley, C; Hopkinson, BM; Todgham, AE; Cross, JN; Greening, H; Williamson, P; Van Hooidonk, R; Deheyn, DD; Johnson, Z | Abstract: The global nature of ocean acidification (OA) transcends habitats, ecosystems, regions, and science disciplines. The scientific community recognizes that the biggest challenge in improving understanding of how changing OA conditions affect ecosystems, and nassociated consequences for human society, requires integration of experimental, observational, and modeling approaches from many disciplines over a wide range of temporal and spatial scales. Such transdisciplinary science is the next step in providing relevant, meaningful results and optimal guidance to policymakers and coastal managers. We discuss the challenges associated with integrating ocean acidification science across funding agencies, institutions, disciplines, topical areas, and regions, and the value of unifying science objectives and activities to deliver insights into local, regional, and global scale impacts. We identify guiding principles and strategies for developing transdisciplinary research in the ocean acidification science community.

Structural colors arising from interactions of light with submicron scale periodic structures have been found in many species across all taxa, serving multiple biological functions including sexual signaling, camouflage, and aposema- tism. Directly inspired by the extensive use of self-assembled melanosomes to produce colors in avian feathers, we set out to synthesize and assemble poly- dopamine-based synthetic melanin nanoparticles in an effort to fabricate colored films. We have quantitatively demonstrated that synthetic melanin nanoparticles have a high refractive index and broad absorption spanning across the UVvisible range, similar to natural melanins. Utilizing a thin-film interference model, we demonstrated the coloration mechanism of deposited films and showed that the unique optical properties of synthetic melanin nanoparticles provide advantages for structural colors over other polymeric nanoparticles (i.e., polystyrene colloidal particles).

Liquid foams are two-phase systems in which a large volume of gas is dispersed as bubbles in a continuous liquid phase. These foams are ubiquitous in nature. In addition, they are found in industrial applications, such as pharmaceutical formulation, food processing, wastewater treatment, construction, and cosmetics. Recently, we reported a new type of foam material, capillary foam, which is stabilized by the synergistic action of particles and a small amount of an immiscible secondary liquid. In this study, we explore in more detail the foam preparation routes. To illustrate some of the potential applications, we create vividly colored wet and dried foams, which are difficult to prepare using traditional methods, and load-bearing porous solids. The combined action of particles and immiscible secondary fluid confers exceptional stability to capillary foams and many options for functionalization, suggesting a wide range of possible applications.

The complete mechanism behind the thermal decomposition of ethylene (C2H4) on Ir(111), which is the first step of graphene growth, is established for the first time employing a combination of experimental and theoretical methods. High-resolution X-ray photoelectron spectroscopy was employed, along with calculations of core level binding-energies, to identify the surface species and their evolution as the surface temperature is increased. To understand the experimental results, we have developed a reaction sequence between the various CnHm species, from ethylene to C monomers and dimers, based on ab initio density functional calculations of all the energy barriers and the Arrhenius prefactors for the most important processes. The resulting temperature evolution of all species obtained from the simulated kinetics of ethylene decomposition agrees with photoemission measurements. The molecular dissociation mechanism begins with the dehydrogenation of ethylene to vinylidene (CH2C), which is then converted to acetylene (CHCH) by the removal and addition of an H atom. The C–C bond is then broken to form methylidyne (CH), and in the same temperature range a small amount of ethylidyne (CH3C) is produced. Finally methylidyne dehydrogenates to produce C monomers that are available for the early stage nucleation of the graphene islands.

Marine worms of the genus Odontosyllis (Syllidae, Annelida) are well known for their spectacular bioluminescent courtship rituals. During the reproductive period, the benthic marine worms leave the ocean floor and swim to the surface to spawn, using bioluminescent light for mate attraction. The behavioral aspects of the courtship ritual have been extensively investigated, but little is known about the origin and evolution of light production in Odontosyllis, which might in fact be a key factor shaping the natural history of the group, as bioluminescent courtship might promote speciation. To investigate the speciation patterns and evolutionary history of Odontosyllis and to trace the origin of bioluminescence within the group, we inferred phylogenies using both gene concatenation and multispecies coalescent species-tree approaches with a multilocus molecular dataset (18S rRNA, 16S rRNA and COI). We also used this dataset to estimate divergence times and diversification rates in a relaxed molecular clock Bayesian framework. Our results suggest that Odontosyllis has undergone a recent rapid radiation, possibly triggered by the origin of bioluminescent courtship, which might have increased speciation rates and lineage divergence through sexual selection. Additionally, our analyses reveal that the genus Odontosyllis as currently delineated is a paraphyletic group that needs to be reorganized to reflect evolutionary relationships.

This review summarizes the existing available data on the use of transcranial Direct Current Stimulation (tDCS) as a treatment for migraine symptoms both with and without aura. 27 studies were examined and 5 were included in the review (which satisfied the inclusion criteria, i.e., duration of tDCS, intensity of stimulation, type of stimulation and stimulated cerebral area). The visual cortex was stimulated in 4 of the 5 analyzed studies. All these studies reported a 1 mA current flowing (anodic stimulation), with a duration of 15-to-20 minutes but not the same montage protocol. The sessions were then repeated 2-4 times a week, for a variable period of 4-8 weeks. The other study adopted a cathodic stimulation on the primary motor cortex with an intensity of 2 mA. Both anodic and cathodic stimulations on the visual cortex provided important results: repeated series of preventive anodic stimulations resulted in a decrease in the regularity of migraine attacks, duration and pain perceived by the patient. The study about the stimulation of the motor cortex pointed out a decrease in the regularity and duration of attacks. Overall, the tDCS can be considered as a useful instrument, capable of bringing benefits to patient suffering from migraine; however, the duration of the obtained benefits was limited in all the cases reported and the size of sample was too small. Further studies are therefore needed to better comprehend the mechanisms involved in the pathogenesis of migraine symptoms.

The formation of nanostructures during metalorganic vapor-phase epitaxy on patterned (001)/(111)B GaAs substrates is reviewed. The focus of this review is on the seminal experiments that revealed the key kinetic processes during nanostructure formation and the theory and modelling that explained the phenomenology in successively greater detail. Experiments have demonstrated that V-groove quantum wires and pyramidal quantum dots result from self-limiting concentration profiles that develop at the bottom of V-grooves and inverted pyramids, respectively. In the 1950s, long before the practical importance of patterned substrates became evident, the mechanisms of capillarity during the equilibration of non-planar surfaces were identified and characterized. This was followed, from the late 1980s by the identification of growth rate anisotropies (i.e. differential growth rates of crystallographic facets) and precursor decomposition anisotropies, with parallel developments in the fabrication of V-groove quantum wires and pyramidal quantum dots. The modelling of these growth processes began at the scale of facets and culminated in systems of coupled reaction-diffusion equations, one for each crystallographic facet that defines the pattern, which takes account of the decomposition and surface diffusion kinetics of the group-III precursors and the subsequent surface diffusion and incorporation of the group-III atoms released by these precursors. Solutions of the equations with optimized parameters produced concentration profiles that provided a quantitative interpretation of the time-, temperature-, and alloy-concentration dependence of the self-ordering process seen in experiments., 26 pages, 13 images

Ferritin, a multimeric cage-like enzyme, is integral to iron metabolism across all phyla through the sequestration and storage of iron through efficient ferroxidase activity. While ferritin sequences from ∼900 species have been identified, crystal structures from only 50 species have been reported, the majority from bacterial origin. We recently isolated a secreted ferritin from the marine invertebrate Chaetopterus sp. (parchment tube worm), which resides in muddy coastal seafloors. Here, we present the first ferritin from a marine invertebrate to be crystallized and its biochemical characterization. The initial ferroxidase reaction rate of recombinant Chaetopterus ferritin (ChF) is 8-fold faster than that of recombinant human heavy-chain ferritin (HuHF). To our knowledge, this protein exhibits the fastest catalytic performance ever described for a ferritin variant. In addition to the high-velocity ferroxidase activity, ChF is unique in that it is secreted by Chaetopterus in a bioluminescent mucus. Previous work has linked the availability of Fe2+ to this long-lived bioluminescence, suggesting a potential function for the secreted ferritin. Comparative biochemical analyses indicated that both ChF and HuHF showed similar behavior toward changes in pH, temperature, and salt concentration. Comparison of their crystal structures shows no significant differences in the catalytic sites. Notable differences were found in the residues that line both 3-fold and 4-fold pores, potentially leading to increased flexibility, reduced steric hindrance, or a more efficient pathway for Fe2+ transportation to the ferroxidase site. These suggested residues could contribute to the understanding of iron translocation through the ferritin shell to the ferroxidase site.

The networks of veins and arteries on the chorionic plate of the human placenta are analyzed in terms of Voronoi cells derived from these networks. Two groups of placentas from the United States are studied: a population cohort with no prescreening, and a cohort from newborns with an elevated risk of developing autistic spectrum disorder. Scaled distributions of the Voronoi cell areas in the two cohorts collapse onto a single distribution, indicating common mechanisms for the formation of the complete vasculatures, but which have different levels of activity in the two cohorts.

Background: Introducing comprehensive smoke-free policies to public places is expected to reduce health costs. This includes prevented health damages by avoiding environmental tobacco smoke (ETS) exposure as well as indirect health benefits from reduced tobacco consumption. Methods: The aim of this study was to estimate direct health costs of ETS exposure in public places and indirect health benefits from reduced tobacco consumption. We calculated attributable hospital days and years of life lost (YLL), based on the observed passive smoking and disease rates in Switzerland. The exposure-response associations of all relevant health outcomes were derived by meta-analysis from prospective cohort studies in order to calculate the direct health costs. To assess the indirect health benefits, a meta-analysis of smoking ban studies on hospital admissions for acute myocardial infarction was conducted. Results: ETS exposure in public places in Switzerland causes 32 000 preventable hospital days (95% CI: 10 000-61 000), 3000 YLL (95% CI: 1000-5000), corresponding to health costs of 330 Mio CHF. The number of hospital days for ischaemic heart disease attributable to passive smoking is much larger if derived from smoking ban studies (41 000) than from prospective cohort studies (3200), resulting in additional health costs of 89 Mio CHF, which are attributed to the indirect health benefits of a smoking ban introduction. Conclusion: The example of smoking ban studies on ischaemic heart disease hospitalization rates suggests that total health costs that can be prevented with smoking bans are considerably larger than the costs arising from the direct health impact of ETS exposure in public places

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurally-coloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm2) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders’ scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required for light-dispersive components to resolve individual wavelengths constrain current spectrometers to bulky sizes, our nano-3D printed prototypes demonstrate that the design principle of the peacock spiders’ scales could inspire novel, miniature light-dispersive components., Several animals and plants get their often spectacular colouration and iridescence from structural colouration. Here, Hsiung et al. show the 3-dimensional nanostructures that produce the rainbow colours on the abdomen of miniature peacock spiders.

Novel transmissive concentrator multijunction (TCMJ) solar cells, and their corresponding module, are here introduced and demonstrated as a promising component of a hybrid concentrator photovoltaic/concentrated solar thermal power (CPV/CSP) system. Using this system, incoming concentrated light can be effectively split into two parts; “in-band”, shorter-wavelength light is absorbed into the TCMJ solar cells to generate electricity, and “out-of-band” light transmits through the cells and module to a thermal receiver where photons are collected as heat that may be used for a variety of purpose. When on-substrate cells are employed, the in-band power conversion efficiencies measured under 1 sun at room temperature are 34.7% and 35.8% and the energy-weighted out-of-band light transmission is 68.6% and 60.8% for the TCMJ cell and module, respectively. We also demonstrate the stability of TCCMJ cells and modules via thermal cycling and show that the temperature of the TCMJ module can be controlled under 105°C via transparent active cooling micro fluidic channels. Thin-film cells fabricated by means of the epitaxial lift-off (ELO) technique are being developed to enhance both the spectrum splitting efficiency and cost effectiveness of this TCMJ module.

The synthesis of transition metal nitride nanoparticles is challenging, in part because the unreactive nature of the most common nitrogen reagents necessitates high-temperature and/or high-pressure reaction conditions. Here we report the solution-phase synthesis and characterization of antiperovskite-type Cu3PdN nanocrystals that are multifaceted, uniform, and highly dispersible as colloidal solutions. Colloidal Cu3PdN nanocrystals were synthesized by reacting copper(II) nitrate and palladium(II) acetylacetonate in 1-octadecene with oleylamine at 240 °C. The Cu3PdN nanocrystals were evaluated as electrocatalysts for the oxygen reduction reaction (ORR) under alkaline conditions, where both Cu3N and Pd nanocrystals are known to be active. The ORR activity of the Cu3PdN nanocrystals appears to be superior to that of Cu3N and comparable to that of Pd synthesized using similar methods, but with significantly improved mass activity than Pd control samples. The Cu3PdN nanocrystals also show greater stability tha...

A detailed review of the literature for the last 5–10 years on epitaxial growth of graphene is presented. Both experimental and theoretical aspects related to growth on transition metals and on silicon carbide are thoroughly reviewed. Thermodynamic and kinetic aspects of growth on all these materials, where possible, are discussed. To make this text useful for a wider audience, a range of important experimental techniques that have been used over the last decade to grow (e.g. CVD, TPG and segregation) and characterize (STM, LEEM, etc.) graphene are reviewed, and a critical survey of most important theoretical techniques is given. Finally, we critically discuss various unsolved problems related to growth and its mechanism which we believe require proper attention in future research.

Weight at delivery is a standard cumulative measure of placental growth. But weight is a crude summary of other placental characteristics, such as the size and shape of the chorionic plate and the location of the umbilical cord insertion. Distributions of such measures across a cohort reveal information about the developmental history of the chorionic plate that is unavailable from an analysis based solely on the mean and standard deviation. Various measures were determined from digitized images of chorionic plates obtained from the Pregnancy, Infection, and Nutrition Study, a prospective cohort study of preterm birth in central North Carolina between 2002 and 2004. The centroids (the geometric centers) and umbilical cord insertions were taken directly from the images. The chorionic plate outlines were obtained from an interpolation based on a Fourier series, while eccentricity (of the best-fit ellipse), skewness, and kurtosis were determined from a shape analysis using the method of moments. The distribution of each variable was compared against the normal, lognormal, and Levy distributions. We found only a single measure (eccentricity) with a normal distribution. All other placental measures required lognormal or "heavy-tailed" distributions to account for moderate to extreme deviations from the mean, where relative likelihoods in the cohort far exceeded those of a normal distribution. Normal and lognormal distributions result from the accumulated effects of a large number of independent additive (normal) or multiplicative (lognormal) events. Thus, while most placentas appear to develop by a series of small, regular, and independent steps, the presence of heavy-tailed distributions suggests that many show shape features which are more consistent with a large number of correlated steps or fewer, but substantially larger, independent steps., Comment: 26 pages, 7 figures, 2 tables

The path integral for classical statistical dynamics is used to determine the properties of one-dimensional Darcy flow through a porous medium with a correlated stochastic permeability for several spatial correlation lengths. Pressure statistics are obtained from the numerical evaluation of the path integral by using the Markov chain Monte Carlo method. Comparisons between these pressure distributions and those calculated from the classic finite-volume method for the corresponding stochastic differential equation show excellent agreement for Dirichlet and Neumann boundary conditions. The evaluation of the variance of the pressure based on a continuum description of the medium provides an estimate of the effects of discretization. Log-normal and Gaussian fits to the pressure distributions as a function of position within the porous medium are discussed in relation to the spatial extent of the correlations of the permeability fluctuations.