Better Fibre Orientation Estimation with Single-Shell Diffusion MRI Using Spherical U-Net

Diffusion MRI is an important technology for detecting human brain nerve pathways,aiding in neuroscience and clinical diagnosis.However,the Multi-ShellMulti-TissueConstrainedSphericalDeconvolution(M-CSD)method,which is a significant technique for reconstructing thefibre orientation distribution func-tion(fODF),requires multishell data with a considerable number of gradient direc-tions to achieve high accuracy.As multishell data are not easy to acquire,the Single-Shell Single-Tissue CSD(S-CSD)suffers from the Partial Volume Effect(PVE).It would be more convenient if we could use single-shell data to reconstruct better fODFs.We propose a novel method that utilizes the spatial structure and anisotropy of dMRI data through a spherical convolution network.We reduce the need for high-quality data by utilizing b=1000 s/mm2 with 60 gradient directions or even less.Our results show that our method outperforms the traditional S-CSD when compared to the M-CSD results as our gold standard.

Using Gaussian Mixture Model to Fix Errors in SFS Approach Based on Propagation

A new Gaussian mixture model is used to improve the quality of propagation method for SFS in this paper. The improved algorithm can overcome most difficulties of propagation SFS method including slow convergence, interdependence of propagation nodes and error accumulation. To slow convergence and interdependence of propagation nodes, stable propagation source and integration path are used to make sure that the reconstruction work of each pixel in the image is independent. A Gaussian mixture model based on prior conditions is proposed to fix the error of integration. Good result has been achieved in the experiment for Lambert composite image of the front illumination.

Preparation and characterization of PVDF-PFSA flat sheet ultrafiltration membranes

High performance polyvinylidene fluoride （PVDF） flat sheet ultrafiltration （UF） membranes have been prepared by an immersion precipitation phase inversion method using perfluorosulfonic acid （PFSA） as a pore former and as a hydrophilic component of the membranes and polyethylene glycol （Mw = 400） （PEG400） as a pore forming agent. The effects of the presence of PEG and the concentration of the PFSA on the phase separation of the casting solutions and on the morphologies and performance of UF membranes including their porosity, water flux, rejection of bovine serum albumin （BSA） protein, and anti-fouling property were investigated. Phase diagrams, viscosities and the phase separations upon exposure to water vapor showed that both PEG400 and PFSA promoted demixing of the casting solution. Scanning electron microscopy measurements showed that the PVDF-PFSA blend membranes had more macropores and finger-like structures than the native PVDF membranes. The PVDF-PFSA membrane （5 wt-% PEG400 ＋ 5 wt-% PFSA） had a pure water flux of 141.7L/m2.h, a BSA rejection of 90.1% and a relative pure water flux reduction （RFR） of 15.28%. These properties were greatly superior to those of the native PVDF membrane （pure water flux of 5.6 L/m2. h, BSA rejection of 96.3% and RFR of 42.86%）.