We report the controlled formation of internally porous polyelectrolyte particles with diameters ranging from tens to hundreds of micrometers through selective solvent extraction using microfluidics. ...Solvent-resistant microdevices, fabricated by frontal photopolymerization, encapsulate binary polymer (P)/solvent (S1) mixtures by a carrier solvent phase (C) to form plugs with well-defined radii and low polydispersity; the suspension is then brought into contact with a selective extraction solvent (S2) that is miscible with C and S1 but not P, leading to the extraction of S1 from the droplets. The ensuing phase inversion yields polymer capsules with a smooth surface but highly porous internal structure. Depending on the liquid extraction time scale, this stage can be carried out in situ, within the chip, or ex situ, in an external S2 bath. Bimodal polymer plugs are achieved using asymmetrically inverted T junctions. For this demonstration, we form sodium poly(styrenesulfonate) (P) particles using water (S1), hexadecane (C), and methyl ethyl ketone (S2). We measure droplet extraction rates as a function of drop size and polymer concentration and propose a simple scaling model to guide particle formation. We find that the extraction time required to form particles from liquid droplets does not depend on the initial polymer concentration but is rather proportional to the initial droplet size. The resulting particle size follows a linear relationship with the initial droplet size for all polymer concentrations, allowing for the precise control of particle size. The internal particle porous structure exhibits a polymer density gradient ranging from a dense surface skin toward an essentially hollow core. Average particle porosities between 10 and 50% are achieved by varying the initial droplet compositions up to 15 wt % polymer. Such particles have potential applications in functional, optical, and coating materials.
Abstract
We perform a full 3D general relativistic magnetohydrodynamical (GRMHD) simulation of an equal-mass, spinning, binary black hole approaching merger, surrounded by a circumbinary disk and ...with a minidisk around each black hole. For this purpose, we evolve the ideal GRMHD equations on top of an approximated spacetime for the binary that is valid in every position of space, including the black hole horizons, during the inspiral regime. We use relaxed initial data for the circumbinary disk from a previous long-term simulation, where the accretion is dominated by a
m
= 1 overdensity called the lump. We compare our new spinning simulation with a previous non-spinning run, studying how spin influences the minidisk properties. We analyze the accretion from the inner edge of the lump to the black hole, focusing on the angular momentum budget of the fluid around the minidisks. We find that minidisks in the spinning case have more mass over a cycle than the non-spinning case. However, in both cases we find that most of the mass received by the black holes is delivered by the direct plunging of material from the lump. We also analyze the morphology and variability of the electromagnetic fluxes, and we find they share the same periodicities of the accretion rate. In the spinning case, we find that the outflows are stronger than the non-spinning case. Our results will be useful to understand and produce realistic synthetic light curves and spectra, which can be used in future observations.
Abstract
Study Objectives
Working outside the conventional “9-to-5” shift may lead to reduced sleep and alertness impairment. Here, we developed an optimization algorithm to identify sleep and work ...schedules that minimize alertness impairment during work hours, while reducing impairment during non-work hours.
Methods
The optimization algorithm searches among a large number of possible sleep and work schedules and estimates their effectiveness in mitigating alertness impairment using the Unified Model of Performance (UMP). To this end, the UMP, and its extensions to estimate sleep latency and sleep duration, predicts the time course of alertness of each potential schedule and their physiological feasibility. We assessed the algorithm by simulating four experimental studies, where we compared alertness levels during work periods for sleep schedules proposed by the algorithm against those used in the studies. In addition, in one of the studies we assessed the algorithm’s ability to simultaneously optimize sleep and work schedules.
Results
Using the same amount of sleep as in the studies but distributing it optimally, the sleep schedules proposed by the optimization algorithm reduced alertness impairment during work periods by an average of 29%. Similarly, simultaneously optimized sleep and work schedules, for a recovery period following a chronic sleep restriction challenge, accelerated the return to baseline levels by two days when compared to the conventional 9-to-5 work schedule.
Conclusions
Our work provides the first quantitative tool to optimize sleep and work schedules and extends the capabilities of existing fatigue-management tools.
Quantum emitters such as the diamond nitrogen-vacancy (NV) center are the basis for a wide range of quantum technologies. However, refraction and reflections at material interfaces impede photon ...collection, and the emitters' atomic scale necessitates the use of free space optical measurement setups that prevent packaging of quantum devices. To overcome these limitations, we design and fabricate a metasurface composed of nanoscale diamond pillars that acts as an immersion lens to collect and collimate the emission of an individual NV center. The metalens exhibits a numerical aperture greater than 1.0, enabling efficient fiber-coupling of quantum emitters. This flexible design will lead to the miniaturization of quantum devices in a wide range of host materials and the development of metasurfaces that shape single-photon emission for coupling to optical cavities or route photons based on their quantum state.
We construct an approximate metric that represents the spacetime of spinning binary black holes (BBH) approaching merger. We build the metric as an analytical superposition of two Kerr metrics in ...harmonic coordinates, where we transform each black hole term with time-dependent boosts describing an inspiral trajectory. The velocities and trajectories of the boost are obtained by solving the post-Newtonian (PN) equations of motion at 3.5 PN order. We analyze the spacetime scalars of the new metric and we show that it is an accurate approximation of Einstein’s field equations in vacuum for a BBH system in the inspiral regime. Furthermore, to prove the effectiveness of our approach, we test the metric in the context of a 3D general relativistic magnetohydrodynamical (GRMHD) simulation of accreting minidisks around the black holes. We compare our results with a previous well-tested spacetime construction based on the asymptotic matching method. We conclude that our new spacetime is well-suited for long-term GRMHD simulations of spinning binary black holes on their way to the merger.
Six millions de français ont subi l’inceste selon un sondage réalisé par la Sofres pour l’Association internationale des victimes de l’inceste en 2006. Dix pour cent des enfants sont maltraités dans ...les pays à hauts revenus. Les troubles que génèrent ces maltraitances, dont l’inceste est la forme la plus sévère, sont l’objet d’un puissant déni qui pourrait être levé en posant systémiquement la question de sa survenue, ce qui nécessite une connaissance minimum de la psychotraumatologie et de la victimologie. L’adulte jeune victime d’inceste présente dans la forme typique un trouble de la personnalité qui se manifeste par : des difficultés à gérer les émotions avec des troubles dissociatifs ; un manque totale de confiance en soi et en toute forme d’aide possible, thérapeutique notamment ; des symptômes comorbides écrans ; une tendance à la répétition littérale du scénario traumatique, notamment dans la relation qui s’instaure avec le thérapeute (transfert et contre-transfert traumatique). Le thérapeute doit mettre en place un cadre thérapeutique qui permet la réécriture de scénario traumatique : recherche systématique de maltraitances infantiles ; rappel de la loi et incitation à porter plainte ; travail en réseau en non pas colloque singulier ; négociation « démocratique » du cadre thérapeutique ; critique du système agresseur qui entretient le déni ; contrôle des contre attitudes de rejet qui affectent les thérapies ; absence de passage. Dans ce contexte relationnel, l’EMDR est une technique qui permet de traiter certains symptômes et, notamment, les intrusions psychotraumatiques caractéristiques de la plupart des troubles psychotraumatiques.
Highlights • Forebrain axonal connections are highly specified by fate determinants. • Their pathfinding is controlled by stereotyped guidance mechanisms. • Guidance cue interactions are becoming ...relevant for topographical tracts. • Reprogramming forebrain connectivity is possible by master gene manipulations.
Ischemic injury represents the most frequent cause of death and disability, and it remains unclear why, of all body organs, the brain is most sensitive to hypoxia. In many tissues, type 4 NADPH ...oxidase is induced upon ischemia or hypoxia, converting oxygen to reactive oxygen species. Here, we show in mouse models of ischemia in the heart, brain, and hindlimb that only in the brain does NADPH oxidase 4 (NOX4) lead to ischemic damage. We explain this distinct cellular distribution pattern through cell-specific knockouts. Endothelial NOX4 breaks down the BBB, while neuronal NOX4 leads to neuronal autotoxicity. Vascular smooth muscle NOX4, the common denominator of ischemia within all ischemic organs, played no apparent role. The direct neuroprotective potential of pharmacological NOX4 inhibition was confirmed in an ex vivo model, free of vascular and BBB components. Our results demonstrate that the heightened sensitivity of the brain to ischemic damage is due to an organ-specific role of NOX4 in blood–brain-barrier endothelial cells and neurons. This mechanism is conserved in at least two rodents and humans, making NOX4 a prime target for a first-in-class mechanism-based, cytoprotective therapy in the unmet high medical need indication of ischemic stroke.
► The conical spouted bed reactor has been proven to be an excellent technology for biomass flash pyrolysis, as bio-oil yields higher than with other technologies are obtained. ► The CSBR allows ...continuous operation, as char is removed from the reaction environment by the segregation of char and sand in the fountain. ► Temperature has great influence on pyrolysis product composition. Thus, the yield of phenolic compounds decreases with temperature in the studied range, 400–600
°C. ► Char properties, such as heating value and surface properties, are improved when pyrolysis is carried out at higher temperatures.
Pinewood sawdust flash pyrolysis has been performed in continuous mode in a pilot plant provided with a conical spouted bed reactor, in the 400–600
°C range. The influence of temperature on the pyrolysis yields and product properties has been studied. Product analysis has been carried out on-line by means of chromatographic methods. High liquid yields have been achieved, with the maximum bio-oil yield (75
wt%) at 500
°C. Gas yield is very low at low temperatures and this fraction is mainly composed of carbon dioxide, carbon monoxide and small amounts of methane, hydrogen and C
2–C
4 hydrocarbons. Bio-oil has been characterized and its major compounds are phenols, specifically guaiacols at low temperatures and catechols at high temperatures. At 600
°C, there is an increase in light compounds due to the cracking reactions, but no aromatic compounds have been detected due to the low residence time of the volatiles in the reactor. The fuel properties of the bio-oil have been measured and the results indicate that it can be a potential substitute to conventional fuels, although its heating value should be improved by subjecting to further treatments. Char can be used as energy source or as active carbon. The char obtained at 600
°C has a high surface area and is suitable for active carbon production.
Using the observations of the EPT (Energetic Particle Telescope) onboard the satellite PROBA‐V, we study the dynamics of inner and outer belt electrons from 500 keV to 8 MeV during quiet periods and ...geomagnetic storms. This high time‐resolution (2‐s) spectrometer operating at the altitude of 820 km on a low polar orbit is providing continuously valuable electrons fluxes for already 5 years. We emphasize especially that some megaeleactron volt electrons are observed in low quantities in the inner belt, even during periods when they are not observed by Van Allen Probes. We show that they are not due to proton contamination but to clear injections of particles from the outer belt during strong geomagnetic storms of March and June 2015, and September 2017. Electrons with lower energy are injected also during less strong storms and the L shell of the electron flux peak in the outer belt shifts inward with a high dependence on the electron energy. With the new high‐resolution EPT instrument, we can study the dynamics of relativistic electrons, including megaelectron volt electrons in the inner radiation belt, revealing how and when such electrons are injected into the inner belt and how long they reside there before being scattered into the Earth's atmosphere or lost by other mechanisms.
Plain Language Summary
New high resolution EPT/PROBA‐V measurements of the electrons fluxes allow us to better understand the dynamics of the electrons in the inner and outer radiation belts. EPT put in perspective the VAP discovery that the expected population of MeV electrons in the inner belt was "missing" and that previous studies suggesting a long‐lived, relatively static inner radiation belts likely misidentified penetrating protons as inner belt electrons. Some MeV electrons are observed by EPT in the inner belt, but in very low quantity. This observation of EPT cannot be due to proton contamination since injections associated to geomagnetic storms are clearly identified. The new capability of EPT to well discriminate the particle species and energy ranges led to new discoveries concerning their source and loss mechanisms regarding the dynamics in this region.
Key Points
Five years of EPT observations show injections of energetic electrons in the slot region and in the inner belt during strong geomagnetic storms
EPT detects megaelectron volt electrons present in the inner belt, especially in the south part of the South Atlantic Anomaly (SAA)
The penetration of the electrons in the SAA is strongly dependent on the geomagnetic activity level and on the energy of the electrons
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