Objectives: To use a novel in vitro model of three-dimensional(3D) neurosphere cultures to assess neurotoxic or neuroprotective effects with harmane as a model compound.Methods: A reproducible model of 3D spheroids wa...Objectives: To use a novel in vitro model of three-dimensional(3D) neurosphere cultures to assess neurotoxic or neuroprotective effects with harmane as a model compound.Methods: A reproducible model of 3D spheroids was developed from embryonic mouse cortical neurons,using molded agarose micro-wells;this method seems particularly practical as it is customizable and widely available and does not require specific cell treatments or assay components different from 2D cultures, allowing for the easy transposition of routine protocols. To assess the neurotoxic effects of harmane, a resazurin assay was performed to measure cell viability, and a highly sensitive fluorometric method, based on the oxidation of dichlorodihydrofluorescein, was applied to measure eventually induced reactive oxygen species(ROS) after exposure to harmane at increasing concentrations of 50 100,and 250 μm.Results: Hydrogel microwells facilitated the assembly of spheroids containing neurons and glial cells into a complex 3D structure and prevented the agglomeration of spheroids. Exposure to harmane induced cytotoxicity in 3D neural spheroids, which was correlated with harmane concentrations, with a 27%reduction in viability at 250 μm. Harmane that did not induce significant levels of oxidative stress was detected for all tested concentrations.Conclusion: This 3D neurosphere model mimics a neuronal microenvironment, allowing a fine study of neurodegenerative disorders and the effects of chemicals on the brain. This model opens novel opportunities, not only from a pathogenetic point of view but also from a therapeutic perspective.展开更多
特高压直流(UHVDC)干式平波电抗器的谐波特征参量直接影响着它的安全稳定运行。为准确测量平波电抗器各次谐波特征参量,从而评估它的性能,通过理论及仿真分析,验证了小电流下的等效测量原理并获得了平波电抗器在双12脉动换流工况下的谐...特高压直流(UHVDC)干式平波电抗器的谐波特征参量直接影响着它的安全稳定运行。为准确测量平波电抗器各次谐波特征参量,从而评估它的性能,通过理论及仿真分析,验证了小电流下的等效测量原理并获得了平波电抗器在双12脉动换流工况下的谐波电流频谱;提出了多谐波特征参量测量系统,并开展了±800 k V特高压平波电抗器特征参量的实测研究。结果表明:电压和电流准确度为0.03%、功率因数角准确度为0.05%时,在95%置信水平下谐波电抗测量不确定度为0.11%,提出的系统能够准备测量平波电抗器特征参量。研究结果可为特高压直流平波电抗器产品设计、性能考核和评估提供方法和指导依据。展开更多
基金funded through a Fonds Medical pour la Recherche dans le Hainaut(FMRH)granta Kangaroo grant from the UMONS Health Institute.
文摘Objectives: To use a novel in vitro model of three-dimensional(3D) neurosphere cultures to assess neurotoxic or neuroprotective effects with harmane as a model compound.Methods: A reproducible model of 3D spheroids was developed from embryonic mouse cortical neurons,using molded agarose micro-wells;this method seems particularly practical as it is customizable and widely available and does not require specific cell treatments or assay components different from 2D cultures, allowing for the easy transposition of routine protocols. To assess the neurotoxic effects of harmane, a resazurin assay was performed to measure cell viability, and a highly sensitive fluorometric method, based on the oxidation of dichlorodihydrofluorescein, was applied to measure eventually induced reactive oxygen species(ROS) after exposure to harmane at increasing concentrations of 50 100,and 250 μm.Results: Hydrogel microwells facilitated the assembly of spheroids containing neurons and glial cells into a complex 3D structure and prevented the agglomeration of spheroids. Exposure to harmane induced cytotoxicity in 3D neural spheroids, which was correlated with harmane concentrations, with a 27%reduction in viability at 250 μm. Harmane that did not induce significant levels of oxidative stress was detected for all tested concentrations.Conclusion: This 3D neurosphere model mimics a neuronal microenvironment, allowing a fine study of neurodegenerative disorders and the effects of chemicals on the brain. This model opens novel opportunities, not only from a pathogenetic point of view but also from a therapeutic perspective.
文摘特高压直流(UHVDC)干式平波电抗器的谐波特征参量直接影响着它的安全稳定运行。为准确测量平波电抗器各次谐波特征参量,从而评估它的性能,通过理论及仿真分析,验证了小电流下的等效测量原理并获得了平波电抗器在双12脉动换流工况下的谐波电流频谱;提出了多谐波特征参量测量系统,并开展了±800 k V特高压平波电抗器特征参量的实测研究。结果表明:电压和电流准确度为0.03%、功率因数角准确度为0.05%时,在95%置信水平下谐波电抗测量不确定度为0.11%,提出的系统能够准备测量平波电抗器特征参量。研究结果可为特高压直流平波电抗器产品设计、性能考核和评估提供方法和指导依据。
