Sensitivity volume as figure-of-merit for maximizing data importance in electrical impedance tomography.

Objective.Electrical impedance tomography (EIT) is a noninvasive imaging method whereby electrical measurements on the periphery of a heterogeneous conductor are inverted to map its internal conductivity. The EIT method proposed here aims to improve computational speed and noise tolerance by introducing sensitivity volume as a figure-of-merit for comparing EIT measurement protocols.Approach.Each measurement is shown to correspond to a sensitivity vector in model space, such that the set of measurements, in turn, corresponds to a set of vectors that subtend a sensitivity volume in model space. A maximal sensitivity volume identifies the measurement protocol with the greatest sensitivity and greatest mutual orthogonality. A distinguishability criterion is generalized to quantify the increased noise tolerance of high sensitivity measurements.Main result.The sensitivity volume method allows the model space dimension to be minimized to match that of the data space, and the data importance to be increased within an expanded space of measurements defined by an increased number of contacts.Significance.The reduction in model space dimension is shown to increasecomputational efficiency, accelerating tomographic inversion by several orders of magnitude, while the enhanced sensitivitytolerates higher noiselevels up to several orders of magnitude larger than standard methods.

Analysis of characteristics related to interstitial lung disease or pulmonary hypertension in patients with dermatomyositis.

INTRODUCTION: Dermatomyositis (DM) is often associated with interstitial lung disease (ILD) or pulmonary hypertension (PH). The aim of this study was to investigate the clinical characteristics of DM patients with ILD or PH. METHODS: This study retrospectively analysed the clinical characteristics of 372 patients with DM, including cytokines, lymphocyte subsets, immunoglobulin and complement. The DM patients were divided into different groups according to whether complicated with ILD, PH or anti-melanoma differentiation-associated gene 5 antibodies (MDA5). A qualitative and quantitative data analysis was performed. RESULTS: IgG, IgA and IgM in the DM-associated ILD (ILD-DM) were higher than that of the DM non-complicating ILD (Non-ILD-DM) (p = 0.022, 0.002 and 0.029, respectively). Meanwhile, IL-6 (p = 0.008) and IL-10 (p = 0.001) were increased in the DM-associated PH (PH-DM) than in the DM non-complicating PH (Non-PH-DM), while IL-17 (p = 0.004), double positive (DP) cell ratio and B lymphocyte ratio were reduced in the PH-DM. Moreover, the incidence of ILD and levels of C4 were higher in the DM with MDA5 (MDA5+ DM) than that of the DM without MDA5. CONCLUSION: ILD-DM has higher IgG, IgA and IgM than that of Non-ILD-DM. PH-DM has higher IL-6, IL-10 and lower IL-17, DP cell ratio and B lymphocyte ratio than that of Non-PH-DM.

Observation of current-induced switching in non-collinear antiferromagnetic IrMn3 by differential voltage measurements.

There is accelerating interest in developing memory devices using antiferromagnetic (AFM) materials, motivated by the possibility for electrically controlling AFM order via spin-orbit torques, and its read-out via magnetoresistive effects. Recent studies have shown, however, that high current densities create non-magnetic contributions to resistive switching signals in AFM/heavy metal (AFM/HM) bilayers, complicating their interpretation. Here we introduce an experimental protocol to unambiguously distinguish current-induced magnetic and nonmagnetic switching signals in AFM/HM structures, and demonstrate it in IrMn3/Pt devices. A six-terminal double-cross device is constructed, with an IrMn3 pillar placed on one cross. The differential voltage is measured between the two crosses with and without IrMn3 after each switching attempt. For a wide range of current densities, reversible switching is observed only when write currents pass through the cross with the IrMn3 pillar, eliminating any possibility of non-magnetic switching artifacts. Micromagnetic simulations support our findings, indicating a complex domain-mediated switching process.