对植物幼苗进行三维重建,常存在叶片间的遮挡、摄像头视野限制等因素导致植物幼苗点云出现缺失的情况,影响了植物表型分析的准确度。为了能获得完整的植物点云,提出了基于多尺度几何感知Transformer(Multi-Scale Geometry-Aware Point T...对植物幼苗进行三维重建,常存在叶片间的遮挡、摄像头视野限制等因素导致植物幼苗点云出现缺失的情况,影响了植物表型分析的准确度。为了能获得完整的植物点云,提出了基于多尺度几何感知Transformer(Multi-Scale Geometry-Aware Point Transformer,MGA-PT)的植物点云补全网络。该网络首先通过降采样特征提取模块对原始点云进行邻域特征提取;然后利用Transformer提取语义信息,引入多尺度几何感知模块提取不同尺度下的几何信息,加强对植株不同器官的特征提取能力;最后使用双路稠密点云生成模块分别对输入部分和预测部分进行细粒度生成,避免输入点云特征的丢失,保证稠密点云贴近实际分布。试验使用基于运动恢复结构的方法对植物幼苗进行三维重建,通过旋转与固定视点缺失构建数据集。试验结果表明,该补全网络表现出色,比目前主流的补全网络更优,对植株数据集补全结果的倒角距离为0.79×10^(-4)cm,地面移动距离为0.11 cm,F1分数为70.77%,且对不同形态、不同比例的缺失均能补全,体现网络具有稳定性与健壮性。该网络对叶类植物补全效果好,为植物幼苗点云补全提供了新思路。展开更多
结合阴离子光电子能谱(Negative Ion Photoelectron Spectroscopy,NIPES)实验和量子化学计算,研究了广泛存在于大气气溶胶中的SO_(3)^(–)和HSO_(3)^(–)的电子结构、微溶剂化作用及其稳定化机制.首先,基于高分辨NIPES测得了上述两种阴...结合阴离子光电子能谱(Negative Ion Photoelectron Spectroscopy,NIPES)实验和量子化学计算,研究了广泛存在于大气气溶胶中的SO_(3)^(–)和HSO_(3)^(–)的电子结构、微溶剂化作用及其稳定化机制.首先,基于高分辨NIPES测得了上述两种阴离子SO_(3)^(–)和HSO_(3)^(–)的垂直电离能((3.31±0.02)和(3.91±0.02)eV)和绝热电离能((3.02±0.05)和(3.56±0.05)eV).进一步发现,结合核系综方法和Dyson轨道计算可以很好地模拟实验测得NIPES,而传统基于态密度方法不能很好地反映核振动效应、电离概率和电离过程中的轨道弛豫效应.此外,系统研究了HSO_(3)^(–)·(H_(2)O)_(n)(n=0~5)体系的微溶剂化效应,结果发现,随着水分子数目的增加,络合体系的稳定性增强,其中静电作用占主导,诱导作用也逐渐发挥重要作用.相信本研究将有利于推动基于硫酸盐的大气气溶胶模型的完善,为有效控制我国雾霾形成提供基础科学依据.展开更多
This paper aims to observe the changes of the inflammatory cytokines in microglial BV2 cells stimulated by apelin, and inves- tigate the mechanism of inflammatory cytokines secretion after apelin stimulation. Immunofl...This paper aims to observe the changes of the inflammatory cytokines in microglial BV2 cells stimulated by apelin, and inves- tigate the mechanism of inflammatory cytokines secretion after apelin stimulation. Immunofluorescence and quantitative re- al-time PCR were performed to observe expression of TNF-α, IL-Iβ, IL-10, MIP-let, and MCP-1 in BV2 cells. Western blot was used to investigate the expression of phosphorylation PI-3K/Akt and phosphorylation Erk signaling pathways in BV2 cells after stimulation by apelin. Furthermore, PI-3K/Akt inhibitor （LY294402） and Erk inhibitor （U0126） were used as antagonists to detect the secretion mechanisms of cytokines in BV2 cells stimulated by apelin. Exogenous recombinant apelin activated the expression of TNF-α, IL-1β, MCP-1 and MIP-1α in BV2 cells by the detection of fluorescence expression and mRNA. Apelin also unregulated the protein expression of p-PI-3K/Akt and p-Erk in BV2 cells induced by apelin. LY294002 and U0126 in- hibited activation of p-PI-3K/Akt and p-Erk expression by Western blot and attenuated the expression of inflammation factors in BV2 cells by fluorescence staining. This study demonstrates that apelin is a potential activator of inflammation factors through the PI3K/Akt and Erk signaling pathway and is potential therapeutically relevant to inflammatory responses of micro- glia cells.展开更多
文摘对植物幼苗进行三维重建,常存在叶片间的遮挡、摄像头视野限制等因素导致植物幼苗点云出现缺失的情况,影响了植物表型分析的准确度。为了能获得完整的植物点云,提出了基于多尺度几何感知Transformer(Multi-Scale Geometry-Aware Point Transformer,MGA-PT)的植物点云补全网络。该网络首先通过降采样特征提取模块对原始点云进行邻域特征提取;然后利用Transformer提取语义信息,引入多尺度几何感知模块提取不同尺度下的几何信息,加强对植株不同器官的特征提取能力;最后使用双路稠密点云生成模块分别对输入部分和预测部分进行细粒度生成,避免输入点云特征的丢失,保证稠密点云贴近实际分布。试验使用基于运动恢复结构的方法对植物幼苗进行三维重建,通过旋转与固定视点缺失构建数据集。试验结果表明,该补全网络表现出色,比目前主流的补全网络更优,对植株数据集补全结果的倒角距离为0.79×10^(-4)cm,地面移动距离为0.11 cm,F1分数为70.77%,且对不同形态、不同比例的缺失均能补全,体现网络具有稳定性与健壮性。该网络对叶类植物补全效果好,为植物幼苗点云补全提供了新思路。
文摘结合阴离子光电子能谱(Negative Ion Photoelectron Spectroscopy,NIPES)实验和量子化学计算,研究了广泛存在于大气气溶胶中的SO_(3)^(–)和HSO_(3)^(–)的电子结构、微溶剂化作用及其稳定化机制.首先,基于高分辨NIPES测得了上述两种阴离子SO_(3)^(–)和HSO_(3)^(–)的垂直电离能((3.31±0.02)和(3.91±0.02)eV)和绝热电离能((3.02±0.05)和(3.56±0.05)eV).进一步发现,结合核系综方法和Dyson轨道计算可以很好地模拟实验测得NIPES,而传统基于态密度方法不能很好地反映核振动效应、电离概率和电离过程中的轨道弛豫效应.此外,系统研究了HSO_(3)^(–)·(H_(2)O)_(n)(n=0~5)体系的微溶剂化效应,结果发现,随着水分子数目的增加,络合体系的稳定性增强,其中静电作用占主导,诱导作用也逐渐发挥重要作用.相信本研究将有利于推动基于硫酸盐的大气气溶胶模型的完善,为有效控制我国雾霾形成提供基础科学依据.
基金supported by European Foundation for the Study of Diabetes/Chinese Diabetes Society/Lilly grant(90561 and 94410)
文摘This paper aims to observe the changes of the inflammatory cytokines in microglial BV2 cells stimulated by apelin, and inves- tigate the mechanism of inflammatory cytokines secretion after apelin stimulation. Immunofluorescence and quantitative re- al-time PCR were performed to observe expression of TNF-α, IL-Iβ, IL-10, MIP-let, and MCP-1 in BV2 cells. Western blot was used to investigate the expression of phosphorylation PI-3K/Akt and phosphorylation Erk signaling pathways in BV2 cells after stimulation by apelin. Furthermore, PI-3K/Akt inhibitor （LY294402） and Erk inhibitor （U0126） were used as antagonists to detect the secretion mechanisms of cytokines in BV2 cells stimulated by apelin. Exogenous recombinant apelin activated the expression of TNF-α, IL-1β, MCP-1 and MIP-1α in BV2 cells by the detection of fluorescence expression and mRNA. Apelin also unregulated the protein expression of p-PI-3K/Akt and p-Erk in BV2 cells induced by apelin. LY294002 and U0126 in- hibited activation of p-PI-3K/Akt and p-Erk expression by Western blot and attenuated the expression of inflammation factors in BV2 cells by fluorescence staining. This study demonstrates that apelin is a potential activator of inflammation factors through the PI3K/Akt and Erk signaling pathway and is potential therapeutically relevant to inflammatory responses of micro- glia cells.
