Toxicity and Applications of Internalised Magnetite Nanoparticles Within Live Paramecium caudatum Cells

© 2017, The Author(s). The nanotechnology revolution has allowed us to speculate on the possibility of hybridising nanoscale materials with live substrates, yet significant doubt still remains pertaining to the effects of nanomaterials on biological matter. In this investigation, we cultivate the ciliated protistic pond-dwelling microorganism Paramecium caudatum in the presence of excessive quantities of magnetite nanoparticles in order to deduce potential beneficial applications for this technique, as well as observe any deleterious effects on the organisms’ health. Our findings indicate that this variety of nanoparticle is well-tolerated by P. caudatum cells, who were observed to consume them in quantities exceeding 5–12% of their body volume: cultivation in the presence of magnetite nanoparticles does not alter P. caudatum cell volume, swimming speed, growth rate or peak colony density and cultures may persist in nanoparticle-contaminated media for many weeks. We demonstrate that P. caudatum cells ingest starch-coated magnetite nanoparticles which facilitates their being magnetically immobilised whilst maintaining apparently normal ciliary dynamics, thus demonstrating that nanoparticle biohybridisation is a viable alternative to conventional forms of ciliate quieting. Ingested magnetite nanoparticle deposits appear to aggregate, suggesting that (a) the process of being internalised concentrates and may therefore detoxify (i.e. render less reactive) nanomaterial suspensions in aquatic environments, and (b) P. caudatum is a candidate organism for programmable nanomaterial manipulation and delivery

Large bolometer arrays with superconducting NbSi sensors for future space experiments

International audienceNew techniques in microelectronics allow to build large arrays of bolometers filling the focal plane of submillimeter and millimeter telescopes. The expected sensitivity increase is the key for the next generation of space experiments in this wavelength range. Superconducting bolometers offer currently the best prospects in terms of sensitivity and multiplexed readout. We present here the developments led in France based on NbSi alloy thermometers. The manufacturing process of a 23 pixel array and the test setup are described

Variable expressivity of FGF3 mutations associated with deafness and LAMM syndrome

<p>Abstract</p> <p>Background</p> <p>Recessive mutations of fibroblast growth factor 3 (FGF3) can cause LAMM syndrome (OMIM 610706), characterized by fully penetrant complete labyrinthine aplasia, microtia and microdontia.</p> <p>Methods</p> <p>We performed a prospective molecular genetic and clinical study of families segregating hearing loss linked to <it>FGF3 </it>mutations. Ten affected individuals from three large Pakistani families segregating <it>FGF3 </it>mutations were imaged with CT, MRI, or both to detect inner ear abnormalities. We also modeled the three dimensional structure of FGF3 to better understand the structural consequences of the three missense mutations.</p> <p>Results</p> <p>Two families segregated reported mutations (p.R104X and p.R95W) and one family segregated a novel mutation (p.R132GfsX26) of <it>FGF3</it>. All individuals homozygous for p.R104X or p.R132GfsX26 had fully penetrant features of LAMM syndrome. However, recessive p.R95W mutations were associated with nearly normal looking auricles and variable inner ear structural phenotypes, similar to that reported for a Somali family also segregating p.R95W. This suggests that the mild phenotype is not entirely due to genetic background. Molecular modeling result suggests a less drastic effect of p.R95W on FGF3 function compared with known missense mutations detected in fully penetrant LAMM syndrome. Since we detected significant intrafamilial variability of the inner ear structural phenotype in the family segregating p.R95W, we also sequenced <it>FGF10 </it>as a likely candidate for a modifier. However, we did not find any sequence variation, pointing out that a larger sample size will be needed to map and identify a modifier. We also observed a mild to moderate bilateral conductive hearing loss in three carriers of p.R95W, suggesting either a semi-dominant effect of this mutant allele of <it>FGF3</it>, otitis media, or a consequence of genetic background in these three family members.</p> <p>Conclusions</p> <p>We noted a less prominent dental and external ear phenotype in association with the homozygous p.R95W. Therefore, we conclude that the manifestations of recessive <it>FGF3 </it>mutations range from fully penetrant LAMM syndrome to deafness with residual inner ear structures and, by extension, with minimal syndromic features, an observation with implications for cochlear implantation candidacy.</p

Habitat properties are key drivers of Borrelia burgdorferi (s.l.) prevalence in Ixodes ricinus populations of deciduous forest fragments

Background: The tick Ixodes ricinus has considerable impact on the health of humans and other terrestrial animals because it transmits several tick-borne pathogens (TBPs) such as B. burgdorferi (sensu lato), which causes Lyme borreliosis (LB). Small forest patches of agricultural landscapes provide many ecosystem services and also the disservice of LB risk. Biotic interactions and environmental filtering shape tick host communities distinctively between specific regions of Europe, which makes evaluating the dilution effect hypothesis and its influence across various scales challenging. Latitude, macroclimate, landscape and habitat properties drive both hosts and ticks and are comparable metrics across Europe. Therefore, we instead assess these environmental drivers as indicators and determine their respective roles for the prevalence of B. burgdorferi in I. ricinus. Methods: We sampled I. ricinus and measured environmental properties of macroclimate, landscape and habitat quality of forest patches in agricultural landscapes along a European macroclimatic gradient. We used linear mixed models to determine significant drivers and their relative importance for nymphal and adult B. burgdorferi prevalence. We suggest a new prevalence index, which is pool-size independent. Results: During summer months, our prevalence index varied between 0 and 0.4 per forest patch, indicating a low to moderate disservice. Habitat properties exerted a fourfold larger influence on B. burgdorferi prevalence than macroclimate and landscape properties combined. Increasingly available ecotone habitat of focal forest patches diluted and edge density at landscape scale amplified B. burgdorferi prevalence. Indicators of habitat attractiveness for tick hosts (food resources and shelter) were the most important predictors within habitat patches. More diverse and abundant macro- and microhabitat had a diluting effect, as it presumably diversifies the niches for tick-hosts and decreases the probability of contact between ticks and their hosts and hence the transmission likelihood.[br/] Conclusions: Diluting effects of more diverse habitat patches would pose another reason to maintain or restore high biodiversity in forest patches of rural landscapes. We suggest classifying habitat patches by their regulating services as dilution and amplification habitat, which predominantly either decrease or increase B. burgdorferi prevalence at local and landscape scale and hence LB risk. Particular emphasis on promoting LB-diluting properties should be put on the management of those habitats that are frequently used by humans. In the light of these findings, climate change may be of little concern for LB risk at local scales, but this should be evaluated further

Hall effects in Carroll dynamics

70 pages,10 figures``Do Carroll particles move?'' The answer depends on the characteristics of the particle such as its mass, spin, electric charge, and magnetic moment. A massive Carroll particle (closely related to fractons) does not move; its immobility follows from the Carroll boost symmetry. A strictly massless Carroll particle may propagate by following the Hall law consistently with partial breaking of their Carroll boost symmetry. In $d=2$ space dimensions, the Carroll group has a two-fold central extension which allows us to generalize the dynamics to massive and massless particles, including anyons. The anyonic spin and magnetic moment combine with the doubly-extended structure parameterized by two Casimir invariants interpreted as intrinsic magnetization and non-commutativity parameter. The extended Carroll particle subjected to an electromagnetic background field moves following a generalized (anomalous) Hall law which includes a Zeeman force. Our theory is illustrated by massless, uncharged anyons with doubly-centrally extended structure (we call ``exotic photons'') which move on the horizon of a Kerr-Newman Black Hole, giving rise to an anyonic spin-Hall Effect

Étude du mode de croissance du Co sur l'Au (111) par photoémission des niveaux de cœur

Nous avons étudié la croissance de films ultra-minces de Co déposés sur une surface d'Au(111), à température ambiante, par photoémission des niveaux de coeur (PES) sous rayonnement synchrotron et par spectroscopie d'électrons Auger (AES). Nous avons observé en PES le niveau de coeur Au 4f7/2 (pic de volume : 84 eV, pic de surface : 83.65 en énergie de liaison) durant la croissance et nous avons suivi l'évolution de l'intensité des transitions Auger Au NVV (69 eV) et Co MVV (53 eV). L'étude de l'intensité et de la position des différentes contributions du pic d'Au 4f7/2 permet la mise en évidence de trois étapes dans la croissance du Co sur l'Au : jusqu'à 1 monocouche (MC) la croissance est tridimensionnelle et la surface n'est qu'à moitié recouverte, entre 1 et 2 MC la surface d'Au non recouverte n'évolue plus : on augmente alors essentiellement la hauteur des îlots. Au dessus de 2 MC, on assiste à une coalescence des îlots qui coïncide avec l'apparition d'un pic d'interdiffusion entre l'Au et le Co à l'interface.We have analysed by means of synchrotron radiation induced angle resolved photoemission spectroscopy (PES) and Auger electron spectroscopy (AES) the growth of Cobalt layers deposited at room temperature on a Au(111) surface. We have studied the behaviour of the Au 4f 7/2 photoemission lines (bulk peak at 84 eV, surface peak at 83.65 eV in binding energy) and Auger transitions (Au NVV at 69 eV, Co MVV at 53 eV). The analysis of the Au 4f 7/2 photoemission core level, for several thicknesses, shows core level shifts corresponding to different environments for the Au atoms. From the evolution of the positions and intensities of the different contributions of Au 4f 7/2 line, three stages in the growth of Co on Au (111) can be deduced. Up until 1 monolayer (ML) of Co deposited, we observe a regular attenuation of the surface line corresponding to a three-dimensional growth : only half of the surface is covered. Between 1 and 2 ML, the uncovered surface does not change : the height of the islands increases. Above 2 ML, the coalescence of islands starts and a third component appears in the photoemission line at a binding energy of 84.4 eV which can be attributed to an interdiffusion between the Co overlayer and the Au substrate at the interface

Hall effects in Carroll dynamics

70 pages,10 figures``Do Carroll particles move?'' The answer depends on the characteristics of the particle such as its mass, spin, electric charge, and magnetic moment. A massive Carroll particle (closely related to fractons) does not move; its immobility follows from the Carroll boost symmetry. A strictly massless Carroll particle may propagate by following the Hall law consistently with partial breaking of their Carroll boost symmetry. In $d=2$ space dimensions, the Carroll group has a two-fold central extension which allows us to generalize the dynamics to massive and massless particles, including anyons. The anyonic spin and magnetic moment combine with the doubly-extended structure parameterized by two Casimir invariants interpreted as intrinsic magnetization and non-commutativity parameter. The extended Carroll particle subjected to an electromagnetic background field moves following a generalized (anomalous) Hall law which includes a Zeeman force. Our theory is illustrated by massless, uncharged anyons with doubly-centrally extended structure (we call ``exotic photons'') which move on the horizon of a Kerr-Newman Black Hole, giving rise to an anyonic spin-Hall Effect