608 research outputs found

    Effects of nanoparticles on murine macrophages

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    Metallic nanoparticles are more and more widely used in an increasing number of applications. Consequently, they are more and more present in the environment, and the risk that they may represent for human health must be evaluated. This requires to increase our knowledge of the cellular responses to nanoparticles. In this context, macrophages appear as an attractive system. They play a major role in eliminating foreign matter, e.g. pathogens or infectious agents, by phagocytosis and inflammatory responses, and are thus highly likely to react to nanoparticles. We have decided to study their responses to nanoparticles by a combination of classical and wide-scope approaches such as proteomics. The long term goal of this study is the better understanding of the responses of macrophages to nanoparticles, and thus to help to assess their possible impact on human health. We chose as a model system bone marrow-derived macrophages and studied the effect of commonly used nanoparticles such as TiO2 and Cu. Classical responses of macrophage were characterized and proteomic approaches based on 2D gels of whole cell extracts were used. Preliminary proteomic data resulting from whole cell extracts showed different effects for TiO2-NPs and Cu-NPs. Modifications of the expression of several proteins involved in different pathways such as, for example, signal transduction, endosome-lysosome pathway, Krebs cycle, oxidative stress response have been underscored. These first results validate our proteomics approach and open a new wide field of investigation for NPs impact on macrophagesComment: Nanosafe2010: International Conference on Safe Production and Use of Nanomaterials 16-18 November 2010, Grenoble, France, Grenoble : France (2010

    Investigating Gender Disparities in Internal Medicine Residency Awards

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    Background: Significant gender disparities persist in career advancement for physicians. Studies have highlighted the lack of female representation in awards from both academic institutions and professional societies; these awards play a role in promotions, making them a fundamental building block of success. Objectives: We aim to explore the gender breakdown among resident awards presented by several Internal Medicine residency programs across the United States in this pilot study. Our ultimate goals are to define disparities in award selection, determine what variables contribute to these disparities, and work to mitigate these variables. Methods/Research: We generated a survey in REDCap to collect retrospective data about resident award selection from academic Internal Medicine residency programs across the country. This survey gathered awards data from 2009-2019 and included variables such as gender breakdown of the program, gender of resident award recipients, and details about how awards are selected. Eight programs completed the survey; these programs were from six different states in various geographic regions. Overall 43.1 percent of residents were female. Across all residency programs and years, there were 51 distinct resident awards with 290 (39.7%) female winners. Of the 51 distinct awards, there were 10 which were awarded to female residents with the same or higher frequency as males; 6 of these mentioned words that have been differentially associated with women in medicine such as “ambulatory,” “community,” “compassion,” and “humanism.” In the 41 awards favoring males, there was only a single mention of the word “compassion,” and no mention of the others. Conclusions/Impact: This data shows a concerning disparity in gender of award winners. In the future we will collect data from more residency programs and perform a thorough investigation of selection mechanisms that may help mitigate bias in order to ultimately propose strategies to reduce these gender disparities.https://jdc.jefferson.edu/sexandgenderhealth/1007/thumbnail.jp

    The Halo Mass of Optically Luminous Quasars at z ,F≈ ,F1-2 Measured via Gravitational Deflection of the Cosmic Microwave Background

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    © 2019. The American Astronomical Society. All rights reserved.We measure the average deflection of cosmic microwave background photons by quasars at 〈Z〉= 1.7. Our sample is selected from the Sloan Digital Sky Survey to cover the redshift range 0.9 ≀z≀2.2 with absolute i-band magnitudes of M i ≀-24 (K-corrected to z = 2). A stack of nearly 200,000 targets reveals an 8ÎŽ detection of Planck's estimate of the lensing convergence toward the quasars. We fit the signal with a model comprising a Navarro-Frenk-White density profile and a two-halo term accounting for correlated large-scale structure, which dominates the observed signal. The best-fitting model is described by an average halo mass log 10 (M h h -1 M)12.6 ±0.2 = and linear bias b=2.7±0.3 at 〈Z 〉= 1.7, in excellent agreement with clustering studies. We also report a hint, at a 90% confidence level, of a correlation between the convergence amplitude and luminosity, indicating that quasars brighter than Miâ‰Č -26 reside in halos of typical mass M h ≈ 10 13 h -1 M, scaling roughly as M h ∞ L opt 3/4 at M i â‰Č-24 mag, in good agreement with physically motivated quasar demography models. Although we acknowledge that this luminosity dependence is a marginal result, the observed Mh-L opt relationship could be interpreted as a reflection of the cutoff in the distribution of black hole accretion rates toward high Eddington ratios: the weak trend of Mh with Lopt observed at low luminosity becomes stronger for the most powerful quasars, which tend to be accreting close to the Eddington limit.Peer reviewedFinal Accepted Versio

    Optimal trapping wavelengths of Cs2_2 molecules in an optical lattice

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    The present paper aims at finding optimal parameters for trapping of Cs2_2 molecules in optical lattices, with the perspective of creating a quantum degenerate gas of ground-state molecules. We have calculated dynamic polarizabilities of Cs2_2 molecules subject to an oscillating electric field, using accurate potential curves and electronic transition dipole moments. We show that for some particular wavelengths of the optical lattice, called "magic wavelengths", the polarizability of the ground-state molecules is equal to the one of a Feshbach molecule. As the creation of the sample of ground-state molecules relies on an adiabatic population transfer from weakly-bound molecules created on a Feshbach resonance, such a coincidence ensures that both the initial and final states are favorably trapped by the lattice light, allowing optimized transfer in agreement with the experimental observation

    Molecular hydrogen in IllustrisTNG galaxies: Carefully comparing signatures of environment with local CO and SFR data

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    We examine how the post-processed content of molecular hydrogen (H2) in galaxies from the TNG100 cosmological, hydrodynamic simulation changes with environment at z = 0, assessing central/satellite status and host halo mass. We make close comparisons with the carbon monoxide (CO) emission survey xCOLD GASS where possible, having mock-observed TNG100 galaxies to match the survey's specifications. For a representative sample of host haloes across 1011 â‰Č M200c/M· < 1014.6, TNG100 predicts that satellites with $m∗ ≄ 109, M⊙ should have a median deficit in their H2 fractions of ∌0.6 dex relative to centrals of the same stellar mass. Once observational and group-finding uncertainties are accounted for, the signature of this deficit decreases to ∌0.2 dex. Remarkably, we calculate a deficit in xCOLD GASS satellites' H2 content relative to centrals of 0.2-0.3 dex, in line with our prediction. We further show that TNG100 and SDSS data exhibit continuous declines in the average star formation rates of galaxies at fixed stellar mass in denser environments, in quantitative agreement with each other. By tracking satellites from their moment of infall in TNG100, we directly show that atomic hydrogen (H i) is depleted at fractionally higher rates than H2 on average. Supporting this picture, we find that the H2/H i mass ratios of satellites are elevated relative to centrals in xCOLD GASS. We provide additional predictions for the effect of environment on H2-both absolute and relative to H i-that can be tested with spectral stacking in future CO surveys

    Evidence for Marine Influence on a Low-Gradient Coastal Plain: Ichnology and Invertebrate Paleontology of the Lower Tongue River Member (Fort Union Formation, Middle Paleocene), Western Williston Basin, U.S.A.

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    The Paleocene Tongue River Member of the Fort Union Formation contains trace-fossil associations indicative of marine influence in otherwise freshwater facies. The identified ichnogenera include: Arenicolites, Diplocraterion, Monocraterion, Ophiomorpha, Rhizocorallium, Skolithos linearis, Teichichnus, Thalassinoides, and one form of uncertain affinity. Two species of the marine diatom Coscinodiscus occur a few meters above the base of the member. The burrows occur in at least five discrete, thin, rippled, fine-grained sandstone beds within the lower 85 m of the member west of the Cedar Creek anticline (CCA) in the Signal Butte, Terry Badlands, and Pine Hills areas. Two discrete burrowed beds are found in the lower 10 m of the member east of the CCA in the little Missouri River area. Abundant freshwater ostracodes include Bisulcocypridea arvadensis, Candona, and Cypridopsis. Freshwater bivalves include Plesielliptio and Pachydon mactriformis. We recognize four fossil assemblages that represent fluvio-lacustrine, proximal estuarine, central estuarine, and distal estuarine environments. Biostratal alternations between fresh- and brackish-water assemblages indicate that the Tongue River Member was deposited along a low-gradient coastal plain that was repeatedly inundated from the east by the Cannonball Sea. The existence of marine-influenced beds in the Tongue River Member invalidates the basis for the Slope Formation

    The Vice Chair of Education in Emergency Medicine: A Workforce Study to Establish the Role, Clarify Responsibilities, and Plan for Success

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    ObjectivesDespite increasing prevalence in emergency medicine (EM), the vice chair of education (VCE) role remains ambiguous with regard to associated responsibilities and expectations. This study aimed to identify training experiences of current VCEs, clarify responsibilities, review career paths, and gather data to inform a unified job description.MethodsA 40‐item, anonymous survey was electronically sent to EM VCEs. VCEs were identified through EM chairs, residency program directors, and residency coordinators through solicitation e‐mails distributed through respective listservs. Quantitative data are reported as percentages with 95% confidence intervals and continuous variables as medians with interquartiles (IQRs). Open‐ and axial‐coding methods were used to organize qualitative data into thematic categories.ResultsForty‐seven of 59 VCEs completed the survey (79.6% response rate); 74.4% were male and 89.3% were white. Average time in the role was 3.56 years (median = 3.0 years, IQR = 4.0 years), with 74.5% serving as inaugural VCE. Many respondents held at least one additional administrative title. Most had no defined job description (68.9%) and reported no defined metrics of success (88.6%). Almost 78% received a reduction in clinical duties, with an average reduction of 27.7% protected time effort (median = 27.2%, IQR = 22.5%). Responsibilities thematically link to faculty affairs and promotion of the departmental educational mission and scholarship.ConclusionGiven the variability in expectations observed, the authors suggest the adoption of a unified VCE job description with detailed responsibilities and performance metrics to ensure success in the role. Efforts to improve the diversity of VCEs are encouraged to better match the diversity of learners.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154254/1/aet210407_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154254/2/aet210407.pd

    Charges and fluxes in Maxwell theory on compact manifolds with boundary

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    We investigate the charges and fluxes that can occur in higher-order Abelian gauge theories defined on compact space-time manifolds with boundary. The boundary is necessary to supply a destination to the electric lines of force emanating from brane sources, thus allowing non-zero net electric charges, but it also introduces new types of electric and magnetic flux. The resulting structure of currents, charges, and fluxes is studied and expressed in the language of relative homology and de Rham cohomology and the corresponding abelian groups. These can be organised in terms of a pair of exact sequences related by the Poincar\'e-Lefschetz isomorphism and by a weaker flip symmetry exchanging the ends of the sequences. It is shown how all this structure is brought into play by the imposition of the appropriately generalised Maxwell's equations. The requirement that these equations be integrable restricts the world-volume of a permitted brane (assumed closed) to be homologous to a cycle on the boundary of space-time. All electric charges and magnetic fluxes are quantised and satisfy the Dirac quantisation condition. But through some boundary cycles there may be unquantised electric fluxes associated with quantised magnetic fluxes and so dyonic in nature.Comment: 28 pages, plain Te

    Low-Temperature Phase Transitions in a Soluble Oligoacene and Their Effect on Device Performance and Stability

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    The use of organic semiconductors in high-performance organic field-effect transistors requires a thorough understanding of the effects that processing conditions, thermal, and bias-stress history have on device operation. Here, we evaluate the temperature dependence of the electrical properties of transistors fabricated with 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene, a material that has attracted much attention recently due to its exceptional electrical properties. We have discovered a phase transition at T = 205 K and discuss its implications on device performance and stability. We examined the impact of this low-temperature phase transition on the thermodynamic, electrical, and structural properties of both single crystals and thin films of this material. Our results show that while the changes to the crystal structure are reversible, the induced thermal stress yields irreversible degradation of the devices

    Prototype tasks: Improving crowdsourcing results through rapid, iterative task design

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    Low-quality results have been a long-standing problem on microtask crowdsourcing platforms, driving away requesters and justifying low wages for workers. To date, workers have been blamed for low-quality results: they are said to make as little effort as possible, do not pay attention to detail, and lack expertise. In this paper, we hypothesize that requesters may also be responsible for low-quality work: they launch unclear task designs that confuse even earnest workers, under-specify edge cases, and neglect to include examples. We introduce prototype tasks, a crowdsourcing strategy requiring all new task designs to launch a small number of sample tasks. Workers attempt these tasks and leave feedback, enabling the requester to iterate on the design before publishing it. We report a field experiment in which tasks that underwent prototype task iteration produced higher-quality work results than the original task designs. With this research, we suggest that a simple and rapid iteration cycle can improve crowd work, and we provide empirical evidence that requester “quality” directly impacts result quality
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