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Per- and polyfluoroalkyl substances (PFASs) are omnipresent and have been shown to induce a wide range of adverse effects, including hepatotoxicity, developmental toxicity and immunotoxicity. So far, little information is available about the mechanisms underlying the toxicity of PFASs, including those related to their immunotoxicity. Reported immunotoxic effects of PFASs include decreased antibody responses in experimental animals and humans, indicating that PFASs may, among others, affect B cell function. In the present study, we first assessed the effects of PFOA on the transcriptome of the human Namalwa B cell line using RNA seq analysis. Gene expression changes, analyzed using Ingenuity Pathway Analysis, pointed to various cellular processes affected by PFOA, including ‘B cell development’ and ‘Primary immunodeficiency signaling’. Interestingly, PFOA decreased the expression of RAG1 and RAG2, genes involved in immunoglobulin and T cell receptor V(D)J recombination. As a next step, time- and concentration-dependent changes in the expression of RAG1 and RAG2 upon exposure to PFOA, PFNA, PFHxS and PFOS were studied through RT-qPCR analysis. Analysis with the concentration–response modeling software PROAST resulted in the following potency ranking: PFNA > PFOA > PFOS > PFHxS. Altogether, the present in vitro study provides insights into the effects of selected PFASs on B cells, identifying RAG1 and RAG2 expression as possible relevant targets that may play a role in the immunotoxicity of PFASs.

The uptake pathways of nanoplastics by edible plants have recently been qualitatively investigated. There is an urgent need to accurately quantify nanoplastics accumulation in plants. Polystyrene (PS) particles with a diameter of 200 nm were doped with the europium chelate Eu-β-diketonate (PS-Eu), which was used to quantify PS-Eu particles uptake by wheat (Triticum aestivum) and lettuce (Lactuca sativa), grown hydroponically and in sandy soil using inductively coupled plasma mass spectrometry. PS-Eu particles accumulated mainly in the roots, while transport to the shoots was limited (for example,3% for 5,000 μg PS particles per litre exposure). Visualization of PS-Eu particles in the roots and shoots was performed with time-gated luminescence through the time-resolved fluorescence of the Eu chelate. The presence of PS-Eu particles in the plant was further confirmed by scanning electron microscopy. Doping with lanthanide chelates provides a versatile strategy for elucidating the interactions between nanoplastics and plants.

A new report from the World Health Organization has evaluated the risks of dietary exposure to nanoplastic and microplastic particles (NMPs) to human health. Although challenges in the detection of NMPs in food and beverages remain, it is clear that humans are being exposed. Presently, no convincing evidence of adverse health effects are found, but major knowledge gaps remain.

Eells and Sober proved in 1983 that screening off is a sufficient condition for the transitivity of probabilistic causality, and in 2003 Shogenji noted that the same goes for probabilistic support. We start this paper by conjecturing that Hans Reichenbach may have been aware of this fact. Then we consider the work of Suppes and Roche, who demonstrated in 1986 and 2012 respectively that screening off can be generalized, while still being sufficient for transitivity. We point out an interesting difference between Reichenbach’s screening off and the generalized version, which we illustrate with an example about haemophilia among the descendants of Queen Victoria. Finally, we embark on a further generalization: we develop a still weaker condition, one that can be made as weak as one wishes.

In a recent paper Ronald Meester and Timber Kerkvliet argue by example that infinite epistemic regresses have different solutions depending on whether they are analyzed with probability functions or with belief functions. Meester and Kerkvliet give two examples, each of which aims to show that an analysis based on belief functions yields a different numerical outcome for the agent’s degree of rational belief than one based on probability functions. In the present paper we however show that the outcomes are the same. The only way in which probability functions and belief functions can yield different solutions for the agent’s degree of belief is if they are applied to different examples, i.e. to different situations in which the agent finds himself.

Purpose The goal of this study is to perform an ex-ante life cycle assessment (LCA) of the emerging gallium-arsenide nanowire tandem solar cells on silicon (GaAs/Si) and to provide a benchmark for the commercialization of the technology. The environmental impacts and energy payback time (EPBT) of the GaAs/Si modules are compared with those of the incumbent single-Si modules. Parameters and efficiencies most relevant to be optimized in order to commercialize the technology are identified and discussed. Methods Two production routes for GaAs/Si solar cells are being up-scaled: the growth of GaAs nanowires on a native substrate, peel-off, and transfer to a silicon substrate (transfer route) and the direct growth of GaAs nanowires on a silicon substrate with assistance of a silicon-dioxide (SiO2) nanotube template (direct growth route). Two ex-ante LCAs for the different manufacturing routes and an LCA for the incumbent single-Si technology were conducted. Environmental impacts of the GaAs/Si technology were assessed and compared with the incumbent. Various scenarios regarding sensitive parameters and processes were modeled—such as modeling several industrial scale tools, the energy consumption of sensitive processes, the number of substrate reuses, the frequency of re-polishing the wafer, and benchmarking the scale of improvement of major impact drivers. Results and discussion The analysis showed that, if expected process efficiencies are achieved, a 28% efficient GaAs/Si module performs 5 to 20% better (transfer route) and 20 to 30% better (direct growth route, except the ozone depletion impact) compared with an 18% efficient single-Si module, for all impact categories assessed—climate change, land use, acidification, ozone depletion, freshwater, marine, terrestrial ecotoxicity, eutrophication, human toxicity, and photochemical oxidation. Critical hotspots identified include the use of gold, trifluoromethane (CHF3), and a GaAs wafer. The EPBT of the GaAs/Si nanowire tandem module is in between 1.37 (expected process efficiencies achieved) and 1.9 years (worst case scenario), while the EPBT of the single-Si module is 1.84 years. Results can be considered as a benchmark for the successful commercialization of the technology. Conclusions If 28% efficient GaAs/Si nanowire tandem modules are developed, expected process efficiencies are achieved, and at least 100 reuses of the GaAs substrate (transfer route) are realized; then, the GaAs/Si modules perform better compared with an 18% efficient single-Si module for most impact categories assessed. Conclusions from the ex-ante LCA are conditional (if-then) and can be used as a benchmark, allowing to quantify the efficiencies that need to be achieved to commercialize the technology.

The plasma-induced charge of non-spherical microparticles is a crucial parameter in complex plasma physics, aerosol science and astrophysics. Yet, the literature describes this charge by two competing models, neither of which has been experimentally verified or refuted. Here we offer experimental proof that the charge on a two-particle cluster (doublet) in the spatial afterglow of a low-pressure plasma equals the charge that would be obtained by the smallest enclosing sphere and that it should therefore not be based on its geometrical capacitance but rather on the capacitance of its smallest enclosing sphere. To support this conclusion, the size, mass and charge of single particles (singlets) and doublets are measured with high precision. The measured ratio between the plasma-afterglow-induced charges on doublets and singlets is compared to both models and shows perfect agreement with the predicted ratio using the capacitance of the smallest enclosing sphere, while being significantly dissimilar to the predicted ratio based on the particle’s geometrical capacitance., Here the authors report measurements of the charge ratio and mass of two-particle clusters and single microparticles in the spatial plasma afterglow. The insights contribute to the general understanding of non-spherical particle charging in ionized gasses.

Environmental waters cover a range of water quality characteristics which could greatly affect the behavior and fate of C60 in the aquatic environment. In this study, the dispersion and stability of C60 in several environmental water matrices during a 70-day extended mixing period were investigated to better understand its environmental behavior and fate in environmental waters. Relatively stable nanoscale aggregates in water (aqu/nC60) could be formed in wastewater influent, while unstable suspensions were obtained in river water, wastewater effluent, seawater, and estuarine water. During the extended mixing under sunlight, oxygen-containing moieties were produced on the surface of the C60 aggregates, independent of the kind of environmental water matrices. Once the mixed system went under quiescent condition, aggregation and sedimentation of aqu/nC60 occurred. However, an extremely short-time disturbance could easily resuspend the C60 aggregates deposited and increase the concentration of aqu/nC60 in the overlying water column. Therefore, the effects of resuspension should be considered when investigating the environmental behavior and fate of C60.

Characterization of species diversity of zooplankton is key to understanding, assessing, and predicting the function and future of pelagic ecosystems throughout the global ocean. The marine zooplankton assemblage, including only metazoans, is highly diverse and taxonomically complex, with an estimated ~28,000 species of 41 major taxonomic groups. This review provides a comprehensive summary of DNA sequences for the barcode region of mitochondrial cytochrome oxidase I (COI) for identified specimens. The foundation of this summary is the MetaZooGene Barcode Atlas and Database (MZGdb), a new open-access data and metadata portal that is linked to NCBI GenBank and BOLD data repositories. The MZGdb provides enhanced quality control and tools for assembling COI reference sequence databases that are specific to selected taxonomic groups and/or ocean regions, with associated metadata (e.g., collection georeferencing, verification of species identification, molecular protocols), and tools for statistical analysis, mapping, and visualization. To date, over 150,000 COI sequences for ~ 5600 described species of marine metazoan plankton (including holo- and meroplankton) are available via the MZGdb portal. This review uses the MZGdb as a resource for summaries of COI barcode data and metadata for important taxonomic groups of marine zooplankton and selected regions, including the North Atlantic, Arctic, North Pacific, and Southern Oceans. The MZGdb is designed to provide a foundation for analysis of species diversity of marine zooplankton based on DNA barcoding and metabarcoding for assessment of marine ecosystems and rapid detection of the impacts of climate change.

InA Treatise of Human Nature, David Hume presents an argument according to which all knowledge reduces to probability, and all probability reduces to nothing. Many have criticized this argument, while others find nothing wrong with it. In this paper we explain that the argument is invalid as it stands, but for different reasons than have been hitherto acknowledged. Once the argument is repaired, it becomes clear that there is indeed something that reduces to nothing, but it is something other than what, according to many, Hume had in mind. Thus two views emerge of what exactly it is that reduces. We surmise that Hume failed to distinguish the two, because he lacked the formal means to differentiate between a rendering of his argument that is in accordance with the probability calculus, and one that is not.

Measuring specific ion fluxes from different regions of the root under practical physiological conditions is crucial for understanding metal uptake mechanisms by plants. We developed and tested a neutral carrier-based liquid-membrane Pb2+ and Cu2+ ion selective microelectrode (ISME) to investigate ion-transport processes along the roots of three common wetland plant species. The Pb2+ and Cu2+ ISME exhibited a Nernstian response with Pb2+ and Cu2+ activities as low as 1.0 nM and 1.0 μM in deionized water and simulated soil solution, respectively. Phragmites australis had a region of Cu2+ release for approximately the first 200 μm, while it exhibited Pb2+ and Cd2+ outward net flux up to the first 500 μm. Although in older sections of the root of Phragmites australis there were areas of influx of Cu2+, Pb2+ and Cd2+, the overall influx was much smaller than that of Typha latifolia or Canna indica. Such a reduced uptake and/or an increased efflux of metal ions across the root-cell plasma-membrane might explain the higher resistance of Phragmites australis to metals, at least in part. The Pb2+ and Cu2+ ISMEs are shown to permit detailed investigation of heavy-metal ion transport in plant roots, especially for plants used for phytoremediation.