The Purkinje system (PS) and the His bundle have been recently implicated as an important driver of the rapid activation rate after 1-2 minutes of ventricular fibrillation (VF). It is unknown whether activations during VF propagate through the His-Purkinje system to other portions of the the working myocardium (WM). Little is known about restitution characteristic differences between the His bundle and working myocardium at short cycle lengths. In this study, rabbit hearts (n=9) were isolated, Langendorff- perfused, and electromechanically uncoupled with blebbistatin (10 μM). Pacing pulses were delivered directly to the His bundle. By using standard glass microelectrodes, action potentials duration (APD) from the His bundle and WM were obtained simultaneously over a wide range of stimulation cycle lengths (CL). The global F-test indicated that the two restitution curves of the His bundle and the WM are statistically significantly different (P<0.05). Also, the APD of the His bundle was significantly shorter than that of WM throughout the whole pacing course (P<0.001). The CL at which alternans developed in the His bundle vs. the WM were shorter for the His bundle (134.2±13.1ms vs. 148.3±13.3ms, P<0.01) and 2:1 block developed at a shorter CL in the His bundle than in WM (130.0±10.0 vs. 145.6±14.2ms, P<0.01). The His bundle APD was significantly shorter than that of WM under both slow and rapid pacing rates, which suggest that there may be an excitable gap during VF and that the His bundle may conduct wavefronts from one bundle branch to the other at short cycle lengths and during VF.
This dataset contains the electric field data sampled along ocean-continent boundaries during space weather hazards. A finite-difference time-domain (FDTD) technique is used to study potential space weather hazards to electric power grids located at the proximity of the coast. The most of the data are in floating point representation, and the data files are in .txt format. The data can be visualized using software such as MATLAB and Python. The data can be used to plot electric and magnetic fields along the ocean-continent boundaries for different scenarios (different depths of an ocean, different conductivities of a lithosphere and different frequencies of ionospheric disturbance).
Evaluator responses to compliance, understandability, actionability, and readability criteria, by base and type, for Hearing Conservation educational materials from active-duty, continental United States Air Force bases.
This dataset is a retrospective study of de-identified electronic-medical record data of transgender and gender-diverse (TGD; i.e. those whose gender identity does not align with their sex assigned at birth) adults 18 years and older who receive gender-affirming care within the University of Utah healthcare system. Gender-affirming care includes gender-affirming hormone therapy (i.e. estrogen- or testosterone-based medications) and gender-affirming surgeries. The goal of creating this dataset is to contribute to the growing literature needed about the TGD population in order to facilitate public health efforts to address health disparities as well as answer clinically impactful questions.
Environmental noise may affect hearing and a variety of non-auditory disease processes. There is some evidence that, like other environmental hazards, noise may be differentially distributed across communities based on socioeconomic status. We aimed to a) predict daytime noise pollution levels and b) assess disparities in daytime noise exposure in Chicago, Illinois. We measured 5-minute daytime noise levels (Leq, 5-min) at 75 randomly selected sites in Chicago in March 2019. Geographically based variables thought to be associated with noise were obtained and used to fit a noise land-use regression model to estimate the daytime environmental noise level at the centroid of the census blocks. Demographic and socioeconomic data were obtained from the City of Chicago for the 77 community areas, and associations with daytime noise levels were assessed using spatial autoregressive models. Mean sampled noise level (Leq, 5-min) was 60.6 dBA. The adjusted R2 and root mean square error of the noise land use regression model and the validation model were 0.60 and 4.67 dBA and 0.51 and 5.90 dBA, respectively. Nearly 75% of city blocks and 85% of city communities have predicted daytime noise level higher than 55 dBA. Of the socioeconomic variables explored, only community per capita income was associated with mean community predicted noise levels and was highest for communities with incomes in the 2nd quartile. Both the noise measurements and land-use regression modeling demonstrate that Chicago has levels of environmental noise likely contributing to the total burden of environmental stressors. Noise is not uniformly distributed across Chicago; it is associated with proximity to roads and public transportation and is higher among communities with mid-to-low incomes per capita, which highlights how socially and economically disadvantaged communities may be disproportionately impacted by this environmental exposure.
This study of the role and impact of the subject selector in academic libraries is unique and long overdue. We focused on the Pac-12 university libraries, a representative sample of nationwide academic libraries. The strength of our investigation is this small, focused sample size and unique statistical analysis of subject specialists. There is a wide variety among these libraries with respect to the hiring requirements for MLIS, the MLIS with an additional advanced-subject master’s degree, and those libraries who hire non-MLIS librarians. This investigation has the possibility of promoting greater awareness for the future of subject specialists in academic libraries.