The increasing number of experimental observations on highly concentrated electrolytes and ionic liquids show qualitative features that are distinct from dilute or moderately concentrated electrolytes, such as self-assembly, multiple-time relaxation, and under-screening, which all impact the emergence of fluid/solid interfaces, and transport in these systems. Since these phenomena are not captured by existing mean field models of electrolytes, there is a paramount need for a continuum framework for highly concentrated electrolytes and ionic liquids. In this work, we present a self-consistent spatiotemporal framework for a ternary composition that comprises ions and solvent employing free energy that consists of short and long range interactions, together with a dissipation mechanism via Onsagers' relations. We show that the model can describe multiple bulk and interfacial morphologies at steady-state. Thus, the dynamic processes in the emergence of distinct morphologies become equally as important as 1

Diffusion MRI studies consistently report group differences in white matter between individuals diagnosed with schizophrenia and healthy controls. Nevertheless, the abnormalities found at the group‐level are often not observed at the individual level. Among the different approaches aiming to study white matter abnormalities at the subject level, normative modeling analysis takes a step towards subject‐level predictions by identifying affected brain locations in individual subjects based on extreme deviations from a normative range. Here, we leveraged a large harmonized diffusion MRI dataset from 512 healthy controls and 601 individuals diagnosed with schizophrenia, to study whether normative modeling can improve subject‐level predictions from a binary classifier. To this aim, individual deviations from a normative model of standard (fractional anisotropy) and advanced (free‐water) dMRI measures, were calculated by means of age and sex‐adjusted z‐scores relative to control data, in 18 white matter regions. Even though larger effect sizes are found when testing for group differences in z‐scores than are found with raw values (p < .001), predictions based on summary z‐score measures achieved low predictive power (AUC < 0.63). Instead, we find that combining information from the different white matter tracts, while using multiple imaging measures simultaneously, improves prediction performance (the best predictor achieved AUC = 0.726). Our findings suggest that extreme deviations from a normative model are not optimal features for prediction. However, including the complete distribution of deviations across multiple imaging measures improves prediction, and could aid in subject‐level classification.

Steady-state solutions of the Poisson-Nernst-Planck model are studied in the asymptotic limit of large, but finite domains. By using asymptotic matching for integrals, we derive an approximate solution for the steady-state equation with exponentially small error with respect to the domain size. The approximation is used to quantify the extent of finite domain effects over the full parameter space. Surprisingly, already for small applied voltages (several thermal voltages), we found that finite domain effects are significant even for large domains (on the scale of hundreds of Debye lengths). Namely, the solution near the boundary, i.e., the boundary layer (electric double layer) structure, is sensitive to the domain size even when the domain size is many times larger than the characteristic width of the boundary layer. We focus on this intermediate regime between confined domains and 'essentially infinite' domains, and study how the domain size effects the solution properties. We conclude by providing an outlook to higher dimensions with applications to ion channels and porous electrodes.

No abstract

A catheter for intra-airway sampling of gas concentrations was constructed from concentric polyethylene tubes. The internal tube (0.58 mm ID, 0.91 mm OD) was connected to a gas analyzer while the external tube (1.20 mm ID, 1.75 mm OD) was constantly flushed by air or a calibration gas, except during sampling. Injection and sampling dead spaces were 0.35 and 0.28 ml, respectively. Delay at 4-ml/min sampling rate was 4.0 +/- 0.2 s. The 0-90% step response to a sudden change in gas composition was 0.24 s when connected to a mass spectrometer. This catheter was used to assess tracer gas dispersion during oscillatory flow (1-20 Hz) in a straight long tube. Local concentrations measured through the catheter, after a small bolus of tracer gas was injected through the external tube, compared favorably with direct measurements through needles inserted via the tube wall and with theoretical predictions. The catheter was also used to measure intra-airway gas concentrations in dog airways during spontaneous breathing, conventional mechanical ventilation, high-frequency ventilation, high-frequency vibration ventilation, and constant-flow ventilation. It ws placed by a fiber-optic bronchoscope and used to measure local quasi-steady concentrations of CO2 and local dispersion with the bolus method. The occurrence of catheter clogging with secretions was substantially reduced with flow through the external tube. Transmitting a calibration gas through the external tube facilitated in situ recalibration of the gas analyzer without removing the catheter. The use of this catheter improved the efficiency and accuracy of measurements of gas concentrations inside lung airways.

Studies applying Free Water Imaging have consistently reported significant global increases in extracellular FW in populations of individuals with early psychosis. However, these published studies focused on homogenous clinical participant groups (e.g., only first episode or chronic), thereby limiting our understanding of the time course of free water (FW) elevations across illness stages. Moreover, the relationship between FW and duration of illness has yet to be directly tested. Leveraging our multi-site diffusion magnetic resonance imaging(dMRI) harmonization approach, we analyzed dMRI scans collected by 12 international sites from 441 healthy controls and 434 individuals diagnosed with schizophrenia-spectrum disorders who represent different illness stages and ages (15–58 years). We characterized the pattern of age-related FW changes by assessing whole brain white matter in individuals with schizophrenia and healthy controls. Quadratic and non-parametric curves were used to model between-group FW differences in averaged whole brain white matter. In individuals with schizophrenia, whole brain FW was higher than in controls across all ages, with the greatest FW values observed from 15 to 23 years of age (effect size range= [0.70-0.87]). Following this peak, FW exhibited a monotonic decrease until reaching a minima at the age of 39 years. After 39 years of age, an attenuated monotonic increase in FW was observed, but with markedly lower effect sizes when compared to younger patients (effect size range = [0.32-0.43]). Importantly, FW was found to be negatively associated with duration of illness in schizophrenia (p=0.006), independent of the effects of age. In summary, our study finds in a large, age-diverse sample that participants with schizophrenia with a shorter duration of illness showed higher FW values compared to participants with more prolonged illness. Our findings indicate that FW might be a reliable imaging marker of acute, extracellular processes which appear to occur predominantly in the early stages of schizophrenia.

No abstract

No abstract