Reactions between silicate deposits and environmental barrier coatings (EBCs) for SiC/SiC composites can severely degrade coating performance. The goal of the present study is to elucidate effects of ...deposit composition and exposure temperature and time on the recession of yttrium disilicate (YDS), a candidate EBC material. Phase equilibrium calculations are used to predict reactions of YDS with deposits of twelve different compositions at 1300 °C and 1400 °C; experimental observations are reported for three exemplary compositions at both temperatures and compared with the thermodynamic predictions. For initial deposit thicknesses of about 100 μm, recession depths reach terminal values after exposures of about 100 h. Terminal recession depths are sensitive to deposit composition but are only weakly affected by temperature. Deposits with high initial Ca:Si ratios react most severely with YDS, forming thick layers containing apatite interpenetrated by residual melt, whereas reactions with deposits that have Ca:Si ratios below a threshold for apatite formation are more benign, albeit still significant.
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The lymphatic vasculature is critical for lung function, but defects in lymphatic function in the pathogenesis of lung disease is understudied. In mice, lymphatic dysfunction alone is sufficient to ...cause lung injury that resembles human emphysema. Whether lymphatic function is disrupted in cigarette smoke (CS)-induced emphysema is unknown. In this study, we investigated the effect of CS on lung lymphatic function. Analysis of human lung tissue revealed significant lung lymphatic thrombosis in patients with emphysema compared to control smokers that increased with disease severity. In a mouse model, CS exposure led to lung lymphatic thrombosis, decreased lymphatic drainage, and impaired leukocyte trafficking that all preceded the development of emphysema. Proteomic analysis demonstrated an increased abundance of coagulation factors in the lymph draining from the lungs of CS-exposed mice compared to control mice. In addition, in vitro assays demonstrated a direct effect of CS on lymphatic endothelial cell integrity. These data show that CS exposure results in lung lymphatic dysfunction and a shift in thoracic lymph towards a prothrombic state. Furthermore, our data suggest that lymphatic dysfunction is due to effects of CS on the lymphatic vasculature that precede emphysema. These studies demonstrate a novel component of CS-induced lung injury that occurs early in the pathogenesis of emphysema.
The aim of this paper is to study the methods for assembly representation supporting the level of automation (LoA) decision process. Based on a literature review on the topic of LoA decision-making, ...a need for involving the assembly sequence in the decision was identified. The representation methods used in both assembly modelling and planning and other more generic approaches in the literature were studied and evaluated. The evaluation has been based on a requirements definition describing how the representation should support the decision about automation. Identified gaps in requirement satisfaction from the existing approaches led to the definition of the assembly sequence modelling language (ASML), a new modelling language that combines principles from and improvements on the studied methods and a standard vocabulary of assembly actions. The modelling language was demonstrated in an assembly example and was successfully evaluated with regard to the defined requirements. Thus, this new modelling approach, ASML, is offered as an innovative and intuitive support in the decision-making process for selecting automation levels in Assembly.
Abstract
Background
Older adults and people from certain racial and ethnic groups are disproportionately represented in coronavirus disease 2019 (COVID-19) hospitalizations and deaths.
Methods
Using ...data from the Premier Healthcare Database on 181 813 hospitalized adults diagnosed with COVID-19 during March–September 2020, we applied multivariable log-binomial regression to assess the associations between age and race/ethnicity and COVID-19 clinical severity (intensive care unit ICU admission, invasive mechanical ventilation IMV, and death) and to determine whether the impact of age on clinical severity differs by race/ethnicity.
Results
Overall, 84 497 (47%) patients were admitted to the ICU, 29 078 (16%) received IMV, and 27 864 (15%) died in the hospital. Increased age was strongly associated with clinical severity when controlling for underlying medical conditions and other covariates; the strength of this association differed by race/ethnicity. Compared with non-Hispanic White patients, risk of death was lower among non-Hispanic Black patients (adjusted risk ratio, 0.96; 95% CI, 0.92–0.99) and higher among Hispanic/Latino patients (risk ratio RR, 1.15; 95% CI, 1.09–1.20), non-Hispanic Asian patients (RR, 1.16; 95% CI, 1.09–1.23), and patients of other racial and ethnic groups (RR, 1.13; 95% CI, 1.06–1.21). Risk of ICU admission and risk of IMV were elevated among some racial and ethnic groups.
Conclusions
These results indicate that age is a driver of poor outcomes among hospitalized persons with COVID-19. Additionally, clinical severity may be elevated among patients of some racial and ethnic minority groups. Public health strategies to reduce severe acute respiratory syndrome coronavirus 2 infection rates among older adults and racial and ethnic minorities are essential to reduce poor outcomes.
We examine how the growth of magnetospheric whistler-mode waves depends on the cold (background) electron number density N0. The analysis is carried out by varying the cold-plasma parameter a = ...(electron gyrofrequency)2/(electron plasma frequency)2 which is proportional to 1/N0. For given values of the thermal anisotropy AT and the ratio Nh/N0, where Nh is the hot (energetic) electron number density, we find that, as N0 decreases, the maximum values of the linear and nonlinear growth rates decrease and the threshold wave amplitude for nonlinear growth increases. Generally, as N0 decreases, the region of (Nh/N0, AT)-parameter space in which nonlinear wave growth can occur becomes more limited; that is, as N0 decreases, the parameter region permitting nonlinear wave growth shifts to the top right of (Nh/N0, AT) space characterized by larger Nh/N0 values and larger AT values. The results have implications for choosing input parameters for full-scale particle simulations and also in the analysis of whistler-mode chorus data.
The Emirates Exploration Imager (EXI) on-board the Emirates Mars Mission (EMM) offers both regional and global imaging capabilities for studies of the Martian atmosphere. EXI is a framing camera with ...a field-of-view (FOV) that will easily capture the martian disk at the EMM science orbit periapsis. EXI provides 6 bandpasses nominally centered on 220, 260, 320, 437, 546, 635 nm using two telescopes (ultraviolet (UV) and visible(VIS)) with separate optics and detectors. Images of the full-disk are acquired with a resolution of 2–4 km per pixel, where the variation is driven by periapsis and apoapsis points of the orbit, respectively. By combining multiple observations within an orbit with planetary rotation, EXI is able to provide diurnal sampling over most of the planet on the scale of 10 days. As a result, the EXI dataset allows for the delineation of diurnal and seasonal timescales in the behavior of atmospheric constituents such as water ice clouds and ozone.
This combination of temporal and spatial distinguishes EXI from somewhat similar imaging systems, including the Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter (MRO) (Malin et al. in Icarus 194(2):501–512,
2008
) and the various cameras on-board the Hubble Space Telescope (HST;
e.g.,
James et al. in J. Geophys. Res. 101(E8):18,883–18,890,
1996
; Wolff et al. in J. Geophys. Res. 104(E4):9027–9042,
1999
). The former, which has comparable spatial and spectral coverage, possesses a limited local time view (e.g., mid-afternoon). The latter, which provides full-disk imaging, has limited spatial resolution through most of the Martian year and is only able to provide (at most) a few observations per year given its role as a dedicated, queue-based astrophysical observatory. In addition to these unique attributes of the EXI observations, the similarities with other missions allows for the leveraging of both past and concurrent observations. For example, with MARCI, one can build on the ∼6 Mars years of daily global UV images as well as those taken concurrently with EXI.
Functionalization of nanoparticles with cationic moieties, such as polyethyleneimine (PEI), enhances binding to the cell membrane; however, it also disrupts the integrity of the cell's plasma and ...vesicular membranes, leading to cell death. Primary fibroblasts were found to display high surface affinity for cationic iron oxide nanoparticles and greater sensitivity than their immortalized counterparts. Treatment of cells with cationic nanoparticles in the presence of incremental increases in serum led to a corresponding linear decrease in cell death. The surface potential of the nanoparticles also decreased linearly as serum increased and this was strongly and inversely correlated with cell death. While low doses of nanoparticles were rendered non-toxic in 25% serum, large doses overcame the toxic threshold. Serum did not reduce nanoparticle association with primary fibroblasts, indicating that the decrease in nanoparticle cytotoxicity was based on serum masking of the PEI surface, rather than decreased exposure. Primary endothelial cells were likewise more sensitive to the cytotoxic effects of cationic nanoparticles than their immortalized counterparts, and this held true for cellular responses to cationic microparticles despite the much lower toxicity of microparticles compared to nanoparticles.
Stochastic simulations are used to characterize the knotting distributions of random ring polymers confined in spheres of various radii. The approach is based on the use of multiple Markov chains and ...reweighting techniques, combined with effective strategies for simplifying the geometrical complexity of ring conformations without altering their knot type. By these means we extend previous studies and characterize in detail how the probability to form a given prime or composite knot behaves in terms of the number of ring segments N and confining radius R. For 50 < or =N < or =450 we show that the probability of forming a composite knot rises significantly with the confinement, while the occurrence probability of prime knots are, in general, nonmonotonic functions of 1R. The dependence of other geometrical indicators, such as writhe and chirality, in terms of R and N is also characterized. It is found that the writhe distribution broadens as the confining sphere narrows.
There are sections where you can revise normal anatomy, test yourself on the top 100 brain structures, or review the imaging appearances of a number of more common neurological conditions.
We have searched the four brightest objects in the Kuiper Belt for the presence of satellites using the newly commissioned Keck Observatory Laser Guide Star Adaptive Optics system. Satellites are ...seen around three of the four objects: Pluto (whose satellite Charon is well-known and whose recently discovered smaller satellites are too faint to be detected), 2003 EL61 (where a second satellite is seen in addition to the previously known satellite), and 2003 UB313 (where a satellite is seen for the first time). The object 2005 FY9, the brightest Kuiper Belt object (KBO) after Pluto, does not have a satellite detectable within 0 4 with a brightness of more than 1% of the primary. The presence of satellites around three of the four brightest KBOs is inconsistent with the fraction of satellites in the Kuiper Belt at large at the 99.2% confidence level, suggesting a different formation mechanism for these largest KBO satellites. The two satellites of 2003 EL61, and the one satellite of 2003 UB313, with fractional brightnesses of 5% and 1.5%, and 2%, of their primaries, respectively, are significantly fainter relative to their primaries than other known KBO satellites, again pointing to possible differences in their origin.
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