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We describe a theoretical and experimental study of an axisymmetric viscous gravity current with a constant flux, confined to the space between two horizontal parallel plates. The effect of confinement results in two regions of flow: an inner region where the fluid is in contact with both plates and an outer annular region where the fluid forms a gravity current along the lower plate. We present a simple theoretical model that describes the flow dynamics by a single dimensionless parameter $J$ , which is the ratio of the characteristic height of an unconfined gravity current to the height of the confined space. Theoretical height profiles display the same characteristics as unconfined gravity currents until $J \approx 0.48$ , where a rapid change in behaviour occurs as confinement comes into effect. For larger values of $J$ , the confined viscous gravity current gradually tends to Hele-Shaw flow, with the transition essentially complete by $J \approx 2$ . We compare the findings from our theoretical model with the results of a series of experiments using golden syrup with various fluxes and gap spacings. Although the data aligns with the major aspects of the model, it is clear that other physics is at play and a single non-dimensional parameter is not sufficient to capture the flow behaviour fully. We speculate on the factors absent in our model that may be responsible for this mismatch.

We consider the multidirectional swelling and drying of hydrogels formed from super-absorbent polymers and water, focusing on the elastic deformation caused by differential swelling. By modelling hydrogels as instantaneously incompressible linear elastic materials and considering situations in which there can be large isotropic strains (arising from swelling), while deviatoric strains remain small, it is possible to describe accurately a wider range of gel states than traditional linear elastic theories allow. An equation is derived relating the displacement field to the polymer fraction in such hydrogels, permitting the shape of the swelling gel to be determined as it evolves in time, using the formulation of Part 1 to find the local polymer fraction. We discuss the boundary conditions to be applied at the edges of a gel, both on the bulk elastic stress and on the pervadic (pore) pressure in the interstices. Similarities between the equation for the displacements and the equations of classical plate theory are investigated by considering a model problem of a slender cylinder with its base immersed in water drying by evaporation into the surrounding air. In this problem, there is differential drying along the axis of the cylinder, as the base remains swollen while the top dries. The results of our displacement formulation agree qualitatively with experiments we have conducted and provide a physical interpretation of the forced biharmonic equation describing the displacement field.

We report an iron-based graphite-conjugated electrocatalyst (GCC-FeDIM) that combines the well-defined nature of homogeneous molecular electrocatalysts with the robustness of a heterogeneous electrode. A suite of spectroscopic methods, supported by the results of DFT calculations, reveals that the electrode surface is functionalized by high spin (

Purpose We examined changes in annual paramedic transport incidence over the ten years prior to COVID-19 in comparison to increases in population growth and emergency department (ED) visitation by walk-in. Methods We conducted a population-level cohort study using the National Ambulatory Care Reporting System from January 1, 2010 to December 31, 2019 in Ontario, Canada. We included all patients triaged in the ED who arrived by either paramedic transport or walk-in. We clustered geographical regions using the Local Health Integration Network boundaries. Descriptive statistics, rate ratios (RR), and 95% confidence intervals were calculated to explore population-adjusted changes in transport volumes. Results Overall incidence of paramedic transports increased by 38.3% (n = 264,134), exceeding population growth fourfold (9.4%) and walk-in ED visitation threefold (13.4%). Population-adjusted transport rates increased by 26.2% (rate ratio 1.26, 95% CI 1.26–1.27) compared to 3.4% for ED visit by walk-in (rate ratio 1.03, 95% CI 1.03–1.04). Patient and visit characteristics remained consistent (age, gender, triage acuity, number of comorbidities, ED disposition, 30-day repeat ED visits) across the years of study. The majority of transports in 2019 had non-emergent triage scores (60.0%) and were discharged home directly from the ED (63.7%). The largest users were persons aged 65 or greater (43.7%). The majority of transports occurred in urbanized regions, though rural and northern regions experienced similar paramedic transport growth rates. Conclusion There was a substantial increase in the demand for paramedic transportation. Growth in paramedic demand outpaced population growth markedly and may continue to surge alongside population aging. Increases in the rate of paramedic transports per population were not bound to urbanized regions, but were province-wide. Our findings indicate a mounting need to develop innovative solutions to meet the increased demand on paramedic services and to implement long-term strategies across provincial paramedic systems.

Background. In suspected myocardial infarction (MI), guidelines recommend using high-sensitivity cardiac troponin (hs-cTn)-based approaches. These require fixed assay-specific thresholds and timepoints, without directly integrating clinical information. Using machine-learning techniques including hs-cTn and clinical routine variables, we aimed to build a digital tool to directly estimate the individual probability of MI, allowing for numerous hs-cTn assays.Methods. In 2,575 patients presenting to the emergency department with suspected MI, two ensembles of machine-learning models using single or serial concentrations of six different hs cTn assays were derived to estimate the individual MI probability (ARTEMIS model). Discriminative performance of the models was assessed using area under the receiver operating characteristic curve (AUC) and logLoss. Model performance was validated in an external cohort with 1,688 patients and tested for global generalizability in 13 international cohorts with 23,411 patients.Results. Eleven routinely available variables including age, sex, cardiovascular risk factors, electrocardiography, and hs-cTn were included in the ARTEMIS models. In the validation and generalization cohorts, excellent discriminative performance was confirmed, superior to hs-cTn only. For the serial hs-cTn measurement model, AUC ranged from 0.92-0.98. Good calibration was observed. Using a single hs-cTn measurement, the ARTEMIS model allowed direct rule-out of MI with very high and similar safety but up to tripled efficiency compared to the guideline-recommended strategy.Conclusion. We developed and validated diagnostic models to accurately estimate the individual probability of MI, which allow for variable hs-cTn use and flexible timing of resampling. Their digital application may provide rapid, safe and efficient personalized patient care.

We consider the multidirectional swelling and drying of hydrogels formed from super-absorbent polymers and water, focusing on the elastic deformation caused by differential swelling. By modelling hydrogels as instantaneously incompressible, linear-elastic materials and considering situations in which there can be large isotropic strains (arising from swelling) while deviatoric strains remain small, it is possible to describe accurately a wider range of gel states than traditional linear elastic theories allow. An equation is derived relating the displacement field to the polymer fraction in such hydrogels, permitting the shape of the swelling gel to be determined as it evolves in time, using the formulation of Part 1 to find the local polymer fraction. We discuss the boundary conditions to be applied at the surfaces of a gel, both on the bulk elastic stress and on the pervadic (pore) pressure in the interstices. Similarities between the equation for the displacements and the equations of classical plate theory are investigated by considering a model problem of a slender cylinder with its base immersed in water drying by evaporation into the surrounding air. In this problem, there is differential drying along the axis of the cylinder, as the base remains swollen while the top dries. The results of our displacement formulation agree qualitatively with experiments that we have conducted, and provide a physical interpretation of the forced biharmonic equation describing the displacement field.

We introduce a new approach for modelling the swelling, drying and elastic behaviour of hydrogels, which leverages the tractability of classical linear-elastic theory whilst incorporating nonlinearities arising from large swelling strains. Relative to a reference state of a fully swollen gel, in which the polymer scaffold may only comprise less than $1\,\%$ of the total volume, a constitutive model for the Cauchy stress tensor is presented, which linearises around small deviatoric strains corresponding to shearing deformations of the material whilst allowing for a nonlinear relation between stress and isotropic strains. Such isotropic strains are considered only to be a consequence of losses and gains of water, while the hydrogel is taken to be instantaneously incompressible. The dynamics governing swelling and drying are described by coupling the interstitial flow of the water through the porous gel with the elastic response of the gel. This approach allows for a complete description of gel behaviour using only three macroscopic polymer-fraction-dependent parameters: an osmotic modulus, a shear modulus and a permeability. It is shown how these three material parameters can, in principle, be determined experimentally using a simple rheometry experiment in which a gel is compressed between two plates surrounded by water and the total force on the top plate is measured. To illustrate our approach, we solve for the swelling of a gel under horizontal confinement and for a partially dried hydrogel bead placed in water.

In a CODE-MI sub-study, six troponin assays were evaluated over 12 months using 3-samples (normal, female and male 99th-percentile levels; n=2,142 results from 67 instruments). Mean differences varied per assay with maximum values being ±4, ±8 and ±9 ng/L at the normal and sex-specific 99th-percentiles, respectively. A pragmatic approach, combining all assays, established maximum differences of ±3 ng/L or ±30%.

We present experiments and theory relating to transpiration through unrestrained hydrogel beads in contact with a water reservoir below and air above. Experimentally, we find that saturated hydrogel beads shrink until a steady state is reached in which water flows continuously through the beads. The size of the bead in steady state is sensitive to the evaporation rate, which depends on the relative humidity and speed of the surrounding air, and to the pressure head imposed by the fluid reservoir. Specifically, the bead size decreases with increasing pressure head or evaporation rate. Our one-dimensional model proposes that transport in the hydrogel is driven by gradients in osmotic pressure, caused by gradients in polymer concentration in the hydrogel that correspond to gradients in swelling. If the evaporation rate or the pressure head changes, the adjustment of this gradient requires the bead to change shape and size. Smaller beads have larger gradients of osmotic pressure, which drive higher transpiration rates and can draw water against larger pressure heads.

Highly concentrated solutions of chlorophyll display rapid fluorescence quenching. The same devastating energy loss is not seen in photosynthetic light-harvesting antenna complexes, despite the need for chromophores to be in close proximity to facilitate energy transfer. A promising, though unconfirmed mechanism for the observed quenching is energy transfer from an excited chlorophyll monomer to a closely associated chlorophyll pair that subsequently undergoes rapid nonradiative decay to the ground state via a short-lived intermediate charge-transfer state. In this work, we make use of newly emerging fast methods in quantum chemistry to assess the feasibility of this proposed mechanism. We calculate rate constants for the initial charge separation, based on Marcus free-energy surfaces extracted from molecular dynamics simulations of solvated chlorophyll pairs, demonstrating that this pathway will compete with fluorescence (i.e., drive quenching) at experimentally measured quenching concentrations. We show that the rate of charge separation is highly sensitive to interchlorophyll distance and the relative orientations of chromophores within a quenching pair. We discuss possible solvent effects on the rate of charge separation (and consequently the degree of quenching), using the light-harvesting complex II (LH2) protein from rps. acidophila as a specific example of how this process might be controlled in a protein environment. Crucially, we reveal that the LH2 antenna protein prevents quenching, even at the high chlorophyll concentrations required for efficient energy transfer, by restricting the range of orientations that neighboring chlorophyll pairs can adopt.

A novel mass spectrometry system is described here comprising a quadrupole-multireflecting time-of-flight design. The new multireflecting time-of-flight analyzer has an effective path length of 48 m and employs planar, gridless ion mirrors providing fourth-order energy focusing resulting in resolving power over 200 000 fwhm and sub-ppm mass accuracy. We show how these attributes are maintained with relatively fast acquisition speeds, setting the system apart from other high resolution mass spectrometers. We have integrated this new system into both liquid chromatography-mass spectrometry and mass spectrometry imaging workflows to demonstrate how the instrument characteristics are of benefit to these applications.

Introduction. The COVID-19 pandemic required providers to re-evaluate traditional models of healthcare delivery. In particular, the proportion of care delivered remotely through telehealth has sharply increased to minimize contact between patients and providers. This shift has magnified barriers associated with telehealth use and disparities among uptake, preference, and acceptability of telehealth solutions. The objective of this scoping review is to document the disparities in telehealth uptake and use that have been documented in literature. Methods and analysis. Following the guidelines of the Joanna Briggs Institute,we will conduct a scoping review of PubMed, CINAHL, and Scopus, as well as several sources of grey literature. Analysis will occur over two stages: title and abstract review, and full-text review. We aim to provide a summary and synthesis of key findings in standardized tables for use at a consensus conference. Ethics and dissemination. Ethics approval is not required for this scoping review because no primary data will be collected. This review will provide the framework for discussion at a consensus conference to develop a patient-centered research agenda to reduce disparities in telehealth uptake and use. We intend to publish our results in a peer-reviewed scientific journal and present them at national conferences.

Despite increased rates of cannabis use among patients with cancer, there are gaps in our understanding of barriers to accessing cannabis. Social determinants of health (SDoH) are associated with access to healthcare, but few studies have evaluated how SDoH relate to cannabis access and use among cancer patients. We examined whether access to and modes of cannabis use differed across indicators of SDoH among patients receiving treatment from a large National Cancer Institute (NCI) designated cancer center. This anonymous cross-sectional survey was developed in collaboration with the NCI Cannabis Supplement consortium, which funded 12 supplements to NCI Center Core Grants across the United States. We evaluated the association of race, gender, income, and age with mode of cannabis use, source of obtaining cannabis, what influences their purchase, and medical cannabis certification status. Overall, 1,053 patients receiving treatment for cancer in Pennsylvania completed the survey and 352 (33.4%) reported using cannabis since their cancer diagnosis. Patients who identified as Black/African-American were less likely to have medical cannabis certifications (p=0.04). Males and Black/African-Americans were more likely to report smoking cannabis (vs other forms, ps

Prescription Drug Monitoring Programs (PDMPs) have shown impacts on a number of opioid-related outcomes but their role in clinician emotional experience of opioid prescribing has not been studied.This study explores the impact of PDMPs on clinician attitudes toward and comfort with opioid prescribing, their satisfaction with patient interactions involving discussion of opioid prescriptions, and their recognition of opioid use disorder (OUD) and ability to refer patients to treatment.Researchers conducted semi-structured interviews with five physicians and two nurse practitioners from a variety of specialties and practice environments.Many participants reported negative emotions surrounding opioid-related patient encounters, with decreased anxiety related to PDMP availability. These effects were less pronounced with clinicians who had greater opioid prescribing experience (either longer careers or higher-volume pain practices). Many participants felt uncomfortable around opioid prescribing. Data from the PDMP often changed prescribing practices, sometimes leading to greater comfort writing a prescription that might have felt riskier without PDMP data. Clinicians easily recognized patient behaviors, symptoms, and prescription requests suggesting that opioid-related adverse events were accumulating, but did not usually apply a label of OUD to these situations. PDMP findings occasionally contributed to a diagnosis and treatment referral for OUD.PDMP data is part of a nuanced approach to prescribing opioids. The objectivity of the data may be helpful in mitigating clinician negative emotions that are common around opioid therapy.

BACKGROUND The 2020 European Society of Cardiology (ESC) guidelines recommend using the 0/1-hour and 0/2-hour algorithms over the 0/3-hour algorithm as the first and second choices of high-sensitivity cardiac troponin (hs-cTn)-based strategies for triage of patients with suspected acute myocardial infarction (AMI). PURPOSE To evaluate the diagnostic accuracies of the ESC 0/1-hour, 0/2-hour, and 0/3-hour algorithms. DATA SOURCES PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus from 1 January 2011 to 31 December 2020. (PROSPERO: CRD42020216479). STUDY SELECTION Prospective studies that evaluated the ESC 0/1-hour, 0/2-hour, or 0/3-hour algorithms in adult patients presenting with suspected AMI. DATA EXTRACTION The primary outcome was index AMI. Twenty unique cohorts were identified. Primary data were obtained from investigators of 16 cohorts and aggregate data were extracted from 4 cohorts. Two independent authors assessed each study for methodological quality. DATA SYNTHESIS A total of 32 studies (20 cohorts) with 30 066 patients were analyzed. The 0/1-hour algorithm had a pooled sensitivity of 99.1% (95% CI, 98.5% to 99.5%) and negative predictive value (NPV) of 99.8% (CI, 99.6% to 99.9%) for ruling out AMI. The 0/2-hour algorithm had a pooled sensitivity of 98.6% (CI, 97.2% to 99.3%) and NPV of 99.6% (CI, 99.4% to 99.8%). The 0/3-hour algorithm had a pooled sensitivity of 93.7% (CI, 87.4% to 97.0%) and NPV of 98.7% (CI, 97.7% to 99.3%). Sensitivity of the 0/3-hour algorithm was attenuated in studies that did not use clinical criteria (GRACE score