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The electron layer structure and physical chemical properties of rare earth elements are very similar, rare earths are difficult to separaterare. Therefore, the extraction of rare earth is always research hot issue in rare earth metallurgy. A new emulsion extractant was prepared with 6%D2EHPA as the flow carrier, 5 % Tl 54 as the surfactant, 3.0 mol/L HCl solution as the inner water phase, sulfonated kerosene as the membrane solvent and control Roi of 1.5. By using the emulsion extractor to extract La3+, Ce3+, Sm3+, Eu3+, Ho3+ and Er3+ in sulfuric acid system, the optimal kinetic conditions for the extraction of RE (III) by emulsion film method (ELM) were determined. The results show that under optimal kinetic conditions of emulsification time of 5 min, extraction time of 6 min, emulsion to water ratio (Rew) of 0.5, extraction temperature of 25 °C, the outer water phase is rare earth element aqueous solution, the highest extraction rate of La3+ is 99.92%, the maximum enrichment ratio is 3.33, and the mass transfer rate k = 9. 35 X 10-10 m/s. The ELM shows excellent extraction performance and enrichment effect for low concentration La3+ solution. [ABSTRACT FROM AUTHOR]

Aiming at the difficulty of extracting and separating of high purity single rare earth elements or compounds, a new emulsion liquid film was constructed and used for the extraction and separation of Re(III) (La3+, Ce3+, Pr3+, Nd3+). The types and concentrations of mobile carriers and surfactants, and the internal water phase in liquid film system were determined by single factor experiment. The results show that the optimal composition of the emulsion liquid membrane system is 6% D2EHPA, 5% T154, 3 mol/L HC1 solution, phase ratio Roi = 1.5. The emulsion film constructed in this system has stable phase and excellent extraction effect, and can realize efficient separation of Re(III). [ABSTRACT FROM AUTHOR]

Proton MR spectra of the brain, especially those measured at short and intermediate echo times, contain signals from mobile macromolecules (MM). A description of the main MM is provided in this consensus paper. These broad peaks of MM underlie the narrower peaks of metabolites and often complicate their quantification but they also may have potential importance as biomarkers in specific diseases. Thus, separation of broad MM signals from low molecular weight metabolites enables accurate determination of metabolite concentrations and is of primary interest in many studies. Other studies attempt to understand the origin of the MM spectrum, to decompose it into individual spectral regions or peaks and to use the components of the MM spectrum as markers of various physiological or pathological conditions in biomedical research or clinical practice. The aim of this consensus paper is to provide an overview and some recommendations on how to handle the MM signals in different types of studies together with a list of open issues in the field, which are all summarized at the end of the paper. [ABSTRACT FROM AUTHOR]

Hippocampus plays a critical role in linking brain energetics and behavior typically associated to stress exposure. In this study, we aimed to simultaneously assess excitatory and inhibitory neuronal metabolism in mouse hippocampus in vivo by applying 18FDG-PET and indirect 13C magnetic resonance spectroscopy (1H-[13C]-MRS) at 14.1 T upon infusion of uniformly 13C-labeled glucose ([U-13C6]Glc). Improving the spectral fitting by taking into account variable decoupling efficiencies of [U-13C6]Glc and refining the compartmentalized model by including two γ-aminobutyric acid (GABA) pools permit us to evaluate the relative contributions of glutamatergic and GABAergic metabolism to total hippocampal neuroenergetics. We report that GABAergic activity accounts for ∼13% of total neurotransmission (VNT) and ∼27% of total neuronal TCA cycle (VTCA) in mouse hippocampus suggesting a higher VTCA/VNT ratio for inhibitory neurons compared to excitatory neurons. Finally, our results provide new strategies and tools for bringing forward the developments and applications of 13C-MRS in specific brain regions of small animals. [ABSTRACT FROM AUTHOR]

Dynamic characteristics of rock masses are an important part of the safety and stability analysis in rock mass engineering. The split Hopkinson pressure bar (SHPB) tests on the phosphate rock in Yichang are conducted, combined with the Split-desktop digital image method and mesoscopic discrete element method (DEM). Both macroscopic and mesoscopic characteristics of the phosphate rock have been studied from such perspectives as stress and strain, fractal characteristics of fragment size, and the spatial and temporal evolution of cracks. The research results show that the dynamic strength of the phosphate rock presents obvious strain rate effect, but the dynamic elasticity modulus is not so sensitive to the strain rate. There is a great correlation between the failure degree of rock specimens and the strain rate. The fractal characteristics of specimen fragments can be used to quantitatively evaluate the rock failure degree under impact loading. According to the characteristics of crack propagation, the rock failure process under the impact can be divided into four stages, namely the elastic crack-free stage, the crack initiation stage, the rapid crack growth stage, and the slow crack development stage. Moreover, with the increase of impact loading, micro-cracks are activated in large quantities. The specimens gradually change from the local damage mode to the axial splitting failure mode and to the crushing failure mode, and in this process, the number of tensile cracks takes an absolute advantage compared with the number of shear cracks. [ABSTRACT FROM AUTHOR]

Despite the improving imaging techniques, it remains challenging to produce magnetic resonance (MR) imaging fingerprints depicting severity of acute ischemia. The aim of this study was to evaluate the potential of the overall high‐field 1H MR Spectroscopy (1H‐MRS) neurochemical profile as a metabolic signature for acute ischemia severity in rodent brains. We modeled global ischemia with one‐stage 4‐vessel‐occlusion (4VO) in rats. Vascular structures were assessed immediately by magnetic resonance angiography. The neurochemical responses in the bilateral cortex were measured 1 h after stroke onset by 1H‐MRS. Then we used Partial‐Least‐Squares discriminant analysis on the overall neurochemical profiles to seek metabolic signatures for ischemic severity subgroups. This approach was further tested on neurochemical profiles of mouse striatum 1 h after permanent middle cerebral artery occlusion, where vascular blood flow was monitored by laser Doppler. Magnetic resonance angiography identified successful 4VO from controls and incomplete global ischemia (e.g., 3VO). 1H‐MR spectra of rat cortex after 4VO showed a specific metabolic pattern, distinct from that of respective controls and rats with 3VO. Partial‐Least‐Squares discriminant analysis on the overall neurochemical profiles revealed metabolic signatures of acute ischemia that may be extended to mice after permanent middle cerebral artery occlusion. Fingerprinting severity of acute ischemia using neurochemical information may improve MR diagnosis in stroke patients. [ABSTRACT FROM AUTHOR]