Exploratory Study on the Methodology of Fast Imaging of Unilateral Stroke Lesions by Electrical Impedance Asymmetry in Human Heads

Stroke has a high mortality and disability rate and should be rapidly diagnosed to improve prognosis. Diagnosing stroke is not a problem for hospitals with CT, MRI, and other imaging devices but is difficult for community hospitals without these devices. Based on the mechanism that the electrical impedance of the two hemispheres of a normal human head is basically symmetrical and a stroke can alter this symmetry, a fast electrical impedance imaging method called symmetrical electrical impedance tomography (SEIT) is proposed. In this technique, electrical impedance tomography (EIT) data measured from the undamaged craniocerebral hemisphere (CCH) is regarded as reference data for the remaining EIT data measured from the other CCH for difference imaging to identify the differences in resistivity distribution between the two CCHs. The results of SEIT imaging based on simulation data from the 2D human head finite element model and that from the physical phantom of human head verified this method in detection of unilateral stroke

Quantitative index of EIT based on 3D abdominal bleeding simulation model

According CT images, a 3D abdominal bleeding simulation model with real shape was set up using COMOSOL Multi-physics. By parameter sweeping, the surface measurement data for EIT were obtained while bleeding from 0~800ml. Total relative changes (TRC) of the data were calculated, shown a linear correlation (R>0.99) with bleeding volume (BV), which implies TRC be a good quantitative index to indicate BV

Association between increased and decreased gut microbiota abundance and Parkinson's disease: A systematic review and subgroup meta-analysis

Objective: The objective of the study was to systematically investigate the association between gut microbiota (GM) abundance and Parkinson's disease (PD). Methods: PubMed, Medline, Cochrane Library and other literature datebase platforms were searched for eligible studies in the English-language from conception to March 1, 2024. Studies evaluating the association between GM and PD were included. The results of the included studies were analyzed using a random effects model with calculation of the mean difference (MD) with the 95 % confidence interval to quantify the incidence of differences in abundance of various bacterial families in PD patients. Continuous models were used to analyze the extracted data. Results: A total of 14 studies with 1045 PD cases and 821 healthy controls were included for data extraction and meta-analysis. All the included studies exhibited reasonable quality. The included studies reported the data on the ratios of 10 families of GM. Of these 10 microbiota families, Bifidobacteriaceae, Ruminococcaceae, Rikenellaceae, Lactobacillaceae, Verrucomicrobiaceae and Christensenellaceae were found to have increased ratios according to the pooled ratios, while Prevotellaceae, Lachnospiraceae, Erysipelotrichaceae and Faecalibacterium were decreased in PD cases. Conclusion: Patients in the PD cohort exhibited distinctive microbiota compositions compared to healthy individuals, with unique differential patterns in gut microbiome abundance at the phylum, family, and genus levels that may be associated wtih PD pathogenesis

Grain coarsening of cast magnesium alloys at high cooling rate: a new observation

Most studies in the area of grain refinement have always taken for granted that higher cooling rate results in finer grains. However, when microstructural variation of the as-cast Mg with cooling rate was investigated using a specially designed V-shaped copper mold, the results were different. Although fast cooling during solidification led to microstructural refining in pure Mg, grain coarsening was observed at a higher cooling rate in Mg alloys that were inoculation treated with 1.0wt pctZr and 1.4wt pctCaO, and in the Mg-Al binary alloys. It is considered that the grain coarsening at higher cooling rate was attributed to the smaller constitutional undercooling zone formed at fast cooling due to the high temperature gradient in the three Mg alloys. These results can help in redefining the role of cooling rate in the grain refinement process

Resistivity and Its Anisotropy Characterization of 3D-Printed Acrylonitrile Butadiene Styrene Copolymer (ABS)/Carbon Black (CB) Composites

The rapid printing of 3D parts with desired electrical properties enables numerous applications. Fused deposition modeling (FDM) using conductive thermoplastic composites has been a valuable approach for such fabrication. The parts produced by FDM possess various controllable structural features, but the effects of the structural features on the electrical properties remain to be determined. This study investigated the effects of these features on the electrical resistivity and resistivity anisotropy of 3D-printed ABS/CB composites. The effects of the process parameters of FDM, including the layer thickness, raster width, and air gap, on the resistivity in both the vertical and horizontal directions for cubic samples were studied because the internal structure of the printed parts depended on those process parameters. The resistivities of printed parts in different parameter combinations were measured by an impedance analyzer and finite element models were created to investigate the relationship between the resistivity and the internal structure. The results indicated that the parameters remarkably affected the resistivity due to the influence of voids and the bonding condition between adjacent fibers. The resistivity in the vertical direction ranged from 70.40 ± 2.88 Ω·m to 180.33 ± 8.21 Ω·m, and the resistivity in the horizontal direction ranged from 41.91 ± 2.29 Ω·m to 58.35 ± 0.61 Ω·m at the frequency of 1 kHz. Moreover, by adjusting the resistivities in different directions, the resistivity anisotropy of the printed parts can be manipulated from 1.01 to 3.59. This research may serve as a reference to fabricate parts with sophisticated geometry with desired electrical resistivity and resistivity anisotropy

pyEIT: A python based framework for Electrical Impedance Tomography

We present a Python-based, open source Electrical Impedance Tomography (EIT) library called pyEIT. It is a multiplatform software released under the Apache License v2.0. pyEIT has a clean architecture and is well documented. It implements state-of-the-art EIT imaging algorithms and is also capable of simple 2D/3D meshing. pyEIT is written in Python. It accelerates the analysis of offline EIT data and can be incorporated into clinical EIT applications. In this paper, we focus on illustrating the fundamental design principles of pyEIT by using some intuitive examples about EIT forward computing and inverse solving. Keywords: Electrical Impedance Tomography, Inverse problems, Finite element method, Unstructrual mes

Local characteristics of molecular epidemiolgy of Acinetobacter baumannii in Jilin province (northeast China)

Highlights 1. The epidemiology of A. baumannii in Jilin Province showed distinctive local characteristic. 2. Newly discovered sequence types (STs), the results of genetic relatedness and geographical distribution of all STs showed epidemiological research by multi-locus sequence typing (MLST) in single hospital is helpful to monitor and control nosocomial infection of A. baumannii. 3. The rate of carbapenems resistance among A. baumannii is about 94% in Jilin province (northeast China). Carbapenems resistance is a helpful factor for predominant STs spreading

In situ compressive investigations on the effects of solid solution Gd on the texture and lattice strain evolution of Mg

The present work studies the effects of solid solution Gd on the texture and lattice strain evolution of an extruded Mg15Gd alloy under uniaxial compression. In situ experiments were carried out using high energy X-ray diffraction on samples of the investigated materials with three different orientations. The original textures of the pure Mg and the Mg15Gd alloy exhibit basal planes that are preferentially parallel and perpendicular to the extrusion direction (ED), respectively. The c/a ratio of the Mg15Gd alloy decreases with increasing Gd content in the solid solution, leading to a different deformation behavior compared with pure Mg under the compressive load. The addition of Gd enhances the slip and twinning modes. However, prismatic slip is activated earlier in the Mg15Gd alloy due to the lower c/a ratio