The vast majority of people worldwide have been impacted by coronavirus disease (COVID-19). In addition to the millions of individuals who have been infected with the disease, billions of individuals ...have been asked or required by local and national governments to change their behavioral patterns. Previous research on epidemics or traumatic events suggests that this can lead to profound behavioral and mental health changes; however, researchers are rarely able to track these changes with frequent, near-real-time sampling or compare their findings to previous years of data for the same individuals.
By combining mobile phone sensing and self-reported mental health data among college students who have been participating in a longitudinal study for the past 2 years, we sought to answer two overarching questions. First, have the behaviors and mental health of the participants changed in response to the COVID-19 pandemic compared to previous time periods? Second, are these behavior and mental health changes associated with the relative news coverage of COVID-19 in the US media?
Behaviors such as the number of locations visited, distance traveled, duration of phone usage, number of phone unlocks, sleep duration, and sedentary time were measured using the StudentLife smartphone sensing app. Depression and anxiety were assessed using weekly self-reported ecological momentary assessments of the Patient Health Questionnaire-4. The participants were 217 undergraduate students, with 178 (82.0%) students providing data during the Winter 2020 term. Differences in behaviors and self-reported mental health collected during the Winter 2020 term compared to previous terms in the same cohort were modeled using mixed linear models.
During the first academic term impacted by COVID-19 (Winter 2020), individuals were more sedentary and reported increased anxiety and depression symptoms (P<.001) relative to previous academic terms and subsequent academic breaks. Interactions between the Winter 2020 term and the week of the academic term (linear and quadratic) were significant. In a mixed linear model, phone usage, number of locations visited, and week of the term were strongly associated with increased amount of COVID-19-related news. When mental health metrics (eg, depression and anxiety) were added to the previous measures (week of term, number of locations visited, and phone usage), both anxiety (P<.001) and depression (P=.03) were significantly associated with COVID-19-related news.
Compared with prior academic terms, individuals in the Winter 2020 term were more sedentary, anxious, and depressed. A wide variety of behaviors, including increased phone usage, decreased physical activity, and fewer locations visited, were associated with fluctuations in COVID-19 news reporting. While this large-scale shift in mental health and behavior is unsurprising, its characterization is particularly important to help guide the development of methods to reduce the impact of future catastrophic events on the mental health of the population.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Recent advances in 3D bioprinting allow for generating intricate structures with dimensions relevant for human tissue, but suitable bioinks for producing translationally relevant tissue with complex ...geometries remain unidentified. Here, a tissue‐specific hybrid bioink is described, composed of a natural polymer, alginate, reinforced with extracellular matrix derived from decellularized tissue (rECM). rECM has rheological and gelation properties beneficial for 3D bioprinting while retaining biologically inductive properties supporting tissue maturation ex vivo and in vivo. These bioinks are shear thinning, resist cell sedimentation, improve viability of multiple cell types, and enhance mechanical stability in hydrogels derived from them. 3D printed constructs generated from rECM bioinks suppress the foreign body response, are pro‐angiogenic and support recipient‐derived de novo blood vessel formation across the entire graft thickness in a murine model of transplant immunosuppression. Their proof‐of‐principle for generating human tissue is demonstrated by 3D bioprinting human airways composed of regionally specified primary human airway epithelial progenitor and smooth muscle cells. Airway lumens remained patent with viable cells for one month in vitro with evidence of differentiation into mature epithelial cell types found in native human airways. rECM bioinks are a promising new approach for generating functional human tissue using 3D bioprinting.
A new class of microscale phase‐separated hybrid bioinks is described by combining tissue specific extracellular matrix (ECM) with alginate. This novel rECM hybrid bioink is tissue specific, cytocompatible, biocompatible, and pro‐angiogenic, and is used to bioprint human airways composed of multiple, regionally specified primary human lung cell types.
Heterogeneous nucleation constitutes the initial step in the formation of new aerosol particles that evolve on the surface of pre-existing (seed) particles. To this end the interaction of vapor and ...seed particle plays a critical role which is governed by the seed particle's size, composition, solubility, electrical charge state as well as the chemical nature of the vapor and the wetting properties of the condensing liquid with the underlying surface. Despite being a process on the nanoscale under most conditions of relevance the effect of heterogeneous nucleation has global implications via the formation of clouds, and is technically utilized in condensation particle counters for the detection of nanoparticles. Proper techniques for the characterization of heterogeneous nucleation thus serve a better fundamental understanding and improve the detectability of nanoparticles. Here we review state-of-the-art experimental and theoretical techniques allowing quantitative analysis of heterogeneous nucleation and providing insight to properties of nucleating clusters. Building upon current knowledge we identify and discuss open questions in the field motivating prospective future research.
•Observation of heterogeneous nucleation on seed particles with diameters well below Kelvin diameter.•Proving the validity of the Kelvin equation on nearly molecular scale.•Characterization of cluster geometry from combined application of Kelvin equation and the heterogeneous nucleation theorem.•Experimental determination of microscopic contact angle and line tension.•Research needs in heterogeneous nucleation.
Generation, investigation, and manipulation of nanostructured materials are of fundamental and practical importance for several disciplines, including materials science and medicine. Recently, ...atmospheric new particle formation in the nanometer-size range has been found to be a global phenomenon. Still, its detailed mechanisms are mostly unknown, largely depending on the incapability to generate and measure nanoparticles in a controlled way. In our experiments, an organic vapor (n-propanol) condenses on molecular ions, as well as on charged and uncharged inorganic nanoparticles, via initial activation by heterogeneous nucleation. We found a smooth transition in activation behavior as a function of size and activation to occur well before the onset of homogeneous nucleation. Furthermore, nucleation enhancement for charged particles and a substantial negative sign preference were quantitatively detected.
Atmospheric aerosol particles have a significant effect on global climate, air quality, and consequently human health. Condensation of organic vapors is a key process in the growth of nanometer-sized ...particles to climate relevant sizes. This growth is very sensitive to the mass accommodation coefficient α, a quantity describing the vapor uptake ability of the particles, but knowledge on α of atmospheric organics is lacking. In this work, we have determined α for four organic molecules with diverse structural properties: adipic acid, succinic acid, naphthalene, and nonane. The coefficients are studied using molecular dynamics simulations, complemented with expansion chamber measurements. Our results are consistent with α = 1 (indicating nearly perfect accommodation), regardless of the molecular structural properties, the phase state of the bulk condensed phase, or surface curvature. The results highlight the need for experimental techniques capable of resolving the internal structure of nanoparticles to better constrain the accommodation of atmospheric organics.
Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the ...fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.
OBJECTIVE To assess the prevalence, clinical presentations, and neuroimaging abnormalities in a series of patients treated for eclampsia at Mayo Clinic in Rochester, MN. PATIENTS AND METHODS We ...reviewed the records of all pregnant patients diagnosed as having eclampsia at Mayo Clinic in Rochester, MN, between January 1, 2001, and December 31, 2008. All patients who underwent neuroimaging were identified, and all studies were reviewed by an independent neuroradiologist. Comparisons were made between groups who did and did not undergo imaging to identify differentiating clinical or laboratory variables. RESULTS Thirteen cases of eclampsia were found, with neuroimaging studies available for 7: magnetic resonance imaging (n=6) and computed tomography (n=1). All 7 patients developed eclamptic seizures, and 2 of 7 patients had severe hypertension, with recorded systolic blood pressures exceeding 180 mm Hg. Neuroimaging showed characteristic changes of posterior reversible encephalopathy syndrome (PRES) in all patients. Follow-up imaging showed resolution in 2 of 3 patients; 1 patient had residual neuroimaging abnormalities. CONCLUSION Our results suggest that the clinical syndrome of eclampsia is associated with an anatomical substrate that is recognizable by neuroimaging as PRES. The levels of blood pressure elevation are lower than those reported in cases of PRES because of hypertensive encephalopathy. Further studies are needed to determine whether more aggressive blood pressure control and early neuroimaging may have a role in the management of these patients.
Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that ...almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100-1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H(2)SO(4)-H(2)O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A re-examination of measurements of heterogeneous nucleation of water vapor on silver nanoparticles is presented here using a model-free framework that derives the energy of critical cluster ...formation directly from measurements of nucleation probability. Temperature dependence is correlated with cluster stabilization by the nanoparticle seed and previously found cases of unusual increasing nucleation onset saturation ratio with increasing temperature are explained. A necessary condition for the unusual positive temperature dependence is identified, namely that the critical cluster be more stable, on a per molecule basis, than the bulk liquid to exhibit the effect. Temperature dependence is next examined in the classical Fletcher model, modified here to make the energy of cluster formation explicit in the model. The contact angle used in the Fletcher model is identified as the microscopic contact angle, which can be directly obtained from heterogeneous nucleation experimental data by a recently developed analysis method. Here an equivalent condition, increasing contact angle with temperature, is found necessary for occurrence of unusual temperature dependence. Our findings have immediate applications to atmospheric particle formation and nanoparticle detection in condensation particle counters (CPCs).
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•Pyrolysis is an alternative to municipal solid waste incineration.•Self-powered pyrolysis can meet CO, NOX, and SO2 EPA emissions standards.•Particulate matter emissions are the ...biggest concern for pyrolysis of waste.•Pyrolysis does not need advanced air pollution control to meet EPA regulations.
Fast pyrolysis of organic wastes has the potential to reduce gaseous emissions and particulate matter compared to waste incineration. Fast pyrolysis converts organic material to a primarily liquid product (bio-oil), which can be burned more cleanly than solid wastes, while still providing heat/power. Pyrolysis reactors can operate without external power by burning pyrolysis products to generate process heat needed to dry feedstock and operate the reactor. The potential of processing organic wastes using pyrolysis was evaluated by determining the total emissions for a pine-fed, fast-pyrolysis system with on-site utilization of pyrolysis products. Emissions were measured during the operation of three different burners fueled by pyrolysis bio-oil, char, and gas. Measured emissions were compared to EPA standards for waste incinerators. Five of the EPA regulated pollutants (Cd, Pb, Hg, HCl, and dioxins/furans) were not observed during testing as they typically depend on feedstock composition (Cd, Pb, Hg, HCl) or are greatly reduced by burning liquid rather than solid fuels (dioxins/furans). Burning pyrolysis products met carbon monoxide (CO), nitrogen oxides (NOX), and sulfur dioxide (SO2) emissions standards at 10.6 ppm, 16.8 ppm, and 2.3 ppm, respectively. PM emissions were measured at 60 mg/m3, which exceeded the EPA limit of 30 mg/m3. However, PM emissions are reducible by using a baghouse filter and optimizing the bio-oil burner air–fuel ratio. These results demonstrated that pyrolysis can convert organic wastes while also meeting CO, NOX, SO2, and PM emission standards set by the EPA for waste incinerators without using advanced air pollution control systems.
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