信号素(Semaphorin)作为一组多功能的蛋白质,占据神经系统功能发育的关键,包括对调节突触形成和神经元的生长的同时,还参与调控细胞周期、影响细胞形态的转变,以及在肿瘤学中,它们能够影响肿瘤细胞的生长、侵袭和转移,以及在免疫反应中...信号素(Semaphorin)作为一组多功能的蛋白质,占据神经系统功能发育的关键,包括对调节突触形成和神经元的生长的同时,还参与调控细胞周期、影响细胞形态的转变,以及在肿瘤学中,它们能够影响肿瘤细胞的生长、侵袭和转移,以及在免疫反应中发挥作用。信号素(Semaphorin, SEMA)是一类分泌型、膜结合型或糖磷脂酰肌醇锚定的糖蛋白,与神经发育、轴突引导、骨分化、心血管系统以及癌症等相关。Sema3F (Semaphorin 3F)是信号素家族轴突引导分子的一种分泌型,参与神经元的发育。Sema3F及其受体神经纤毛蛋白-2在胚胎小鼠大脑区域(包括嗅球、海马体和大脑皮层)中以互斥方式表达。Sema3F作用在神经元上,可引起下游因子的改变,包括CREBBP、CREB、VEGF等,能够下调P53表达、影响GABA能系统、下调RacGTP水平、促进CRMP2磷酸化等。本文通过综述的方法,对Sema3F在神经元下游因子进行叙述,为研究Sema3F在神经元中的功能提供帮助。Semaphorin, as a group of multifunctional proteins, plays a crucial role in the functional development of the nervous system. It not only regulates synapse formation and the growth of neurons but also participates in the regulation of the cell cycle, influences the transformation of cell morphology. Moreover, in oncology, it can affect the growth, invasion and metastasis of tumor cells and also plays a role in immune responses. Semaphorin (SEMA) is a type of secreted, membrane-bound or glycosylphosphatidylinositol-anchored glycoprotein, which is related to neural development, axon guidance, bone differentiation, the cardiovascular system and cancer, etc. Sema3F, a secreted form of the axon guidance molecules in the Semaphorin family, is involved in the development of neurons. Sema3F and its receptor neuropilin-2 are expressed in a mutually exclusive manner in the brain regions (including the olfactory bulb, hippocampus and cerebral cortex) of embryonic mice. When Sema3F acts on neurons, it can cause changes in downstream factors, including CREBBP, CREB, VEGF, etc. It can downregulate the expression of P53, affect the GABAergic system, downregulate the level of RacGTP and promote the phosphorylation of CRMP2, etc. Through the method of review, this article describes the downstream factors of Sema3F in neurons, aiming to provide assistance for the research on the functions of Sema3F in neurons.展开更多
本文通过综述的形式,论述了保守轴突导向因子Semaphorins的信号蛋白Semaphorins3F (Sema3F)的在神经系统中作用的研究。基于对Sema3F的概述,我们对神经的作用进行了系统总结。在神经发育的过程中,Sema3F作为调节因子,参与皮层椎体神经...本文通过综述的形式,论述了保守轴突导向因子Semaphorins的信号蛋白Semaphorins3F (Sema3F)的在神经系统中作用的研究。基于对Sema3F的概述,我们对神经的作用进行了系统总结。在神经发育的过程中,Sema3F作为调节因子,参与皮层椎体神经元树突密度的调节及诱导树突消除和树突细胞体的回缩等多种功能。同样在对Sema3F在感觉神经中的作用的研究中,我们发现其对于嗅觉系统、视觉、内耳和牙神经等有着重要的作用。本文还探讨了Sema3F对于包括自闭症、精神分裂症和癫痫等神经系统疾病的作用。我们认为,Sema3F在神经元的发育、感觉神经以及多种神经系统疾病中均起着重要的作用。This article, in the form of a review, discusses the research on the role of the semaphorin family member Semaphorin 3F (Sema3F), a conserved axon guidance molecule, in the nervous system. Based on an overview of Sema3F, we systematically summarize its effects on neurons. During the process of neural development, Sema3F acts as a regulatory factor, participating in the modulation of dendritic density in cortical pyramidal neurons, as well as inducing dendritic elimination and retraction of dendritic cell bodies, among other functions. Similarly, in studies on the role of Sema3F in sensory neurons, we have found that it plays an important role in the olfactory system, vision, inner ear, and dental nerves. The article also explores the role of Sema3F in various neurological disorders, including autism, schizophrenia, and epilepsy. We believe that Sema3F plays a significant role in the development of neurons, sensory neurons, and a variety of neurological diseases.展开更多
The Hyperspectral Infrared Atmospheric Sounder-II(HIRAS-II)onboard China’s FungYun(FY)-3F meteorological satellite was launched in August 2023.This study presents the first attempt to retrieve the global carbon monox...The Hyperspectral Infrared Atmospheric Sounder-II(HIRAS-II)onboard China’s FungYun(FY)-3F meteorological satellite was launched in August 2023.This study presents the first attempt to retrieve the global carbon monoxide(CO)column from HIRAS-II/FY-3F spectra based on a newly established full-physics algorithm.The CO global columns derived from the HIRAS-II/FY-3F satellite are compared to measurements from the Infrared Atmospheric Sounding Interferometer(IASI)onboard Europe’s MetopB satellite,as both satellites have the same spectral range with a similar overpass time.The correlation coefficient between the IASI/Metop-B and HIRAS-II/FY-3F CO retrievals is about 0.8.The HIRAS-II/FY-3F satellite can capture well the regions with high CO values,e.g.,Africa,North America,and East Asia.The relative difference in the CO global column between HIRAS-II and IASI is 1.2±13.7(1)%,which is within their combined retrieval uncertainty.The CO plumes from the fire emissions in North America between 18 and 23 July 2024 were observed by the HIRAS-II/FY-3F satellite and consistent with the CAMS(Copernicus Atmosphere Monitoring Service)model simulations.Our results show that the HIRAS-II/FY-3F spectra are of good enough quality to provide quantitative observations of global CO column remote sensing observations.展开更多
目前在电力行业中广泛应用的SF6气体具有严重的温室效应,寻找一种绝缘性能优良的环保型替代气体成为研究热点。近年来,C3F7CN及其混合气体凭借出色的绝缘性能和环保特性得到了国内外学者的广泛关注。目前针对其放电分解机理的研究较少...目前在电力行业中广泛应用的SF6气体具有严重的温室效应,寻找一种绝缘性能优良的环保型替代气体成为研究热点。近年来,C3F7CN及其混合气体凭借出色的绝缘性能和环保特性得到了国内外学者的广泛关注。目前针对其放电分解机理的研究较少。首先,基于ReaxFF反应分子动力学方法和密度泛函理论,从微观层面模拟研究了C3F7CN/CO2混合气体的分解机理。基于构建的C3F7CN/CO2混合气体模型,研究了温度对C3F7CN分解过程的影响,分析了其可能的分解路径、产物类型及分布等。计算结果表明,C3F7CN在局部过热或放电等故障条件下分解容易产生CF3·、C3F7·、C·、CF3CFCN·、CF2·和F·等各类自由基,上述自由基复合将产生CF4、C2F6、C3F8、CF3CN、CO等产物。其次,利用气体绝缘试验平台和气相色谱质谱联用仪(gas chromatography mass spectrometer,GC-MS),试验分析了其多次击穿后的分解产物。试验结果表明,混合气体多次击穿后的主要分解产物是CF4、C2F6、CF3CN。这些产物分子均具有比较好的绝缘能力,保障了C3F7CN/CO2混合气体的绝缘性能不被破环。相关结论为进一步探究C3F7CN/CO2混合气体的绝缘特性及协同效应等课题提供理论依据和工程指导。展开更多
为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数...为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数据划分成信号帧和噪声帧,采用3F–C法估计了白噪声和窄带干扰参数。通过仿真实验和实测数据处理,与传统小波包降噪方法的结果进行了对比。数据分析结果表明:无论是针对单一白噪声环境还是存在窄带干扰的混合噪声环境,该能量估计方法的准确性均优于传统小波包降噪方法,且随着信噪比的降低和信号时间窗口长度的增加,该方法表现出更明显的优势。在信噪比为–8 d B的条件下,使用该方法对实测局部放电脉冲信号进行能量估计的相对误差仅为4.07%,而使用小波包降噪方法时相对误差则达到44.12%。展开更多
文摘信号素(Semaphorin)作为一组多功能的蛋白质,占据神经系统功能发育的关键,包括对调节突触形成和神经元的生长的同时,还参与调控细胞周期、影响细胞形态的转变,以及在肿瘤学中,它们能够影响肿瘤细胞的生长、侵袭和转移,以及在免疫反应中发挥作用。信号素(Semaphorin, SEMA)是一类分泌型、膜结合型或糖磷脂酰肌醇锚定的糖蛋白,与神经发育、轴突引导、骨分化、心血管系统以及癌症等相关。Sema3F (Semaphorin 3F)是信号素家族轴突引导分子的一种分泌型,参与神经元的发育。Sema3F及其受体神经纤毛蛋白-2在胚胎小鼠大脑区域(包括嗅球、海马体和大脑皮层)中以互斥方式表达。Sema3F作用在神经元上,可引起下游因子的改变,包括CREBBP、CREB、VEGF等,能够下调P53表达、影响GABA能系统、下调RacGTP水平、促进CRMP2磷酸化等。本文通过综述的方法,对Sema3F在神经元下游因子进行叙述,为研究Sema3F在神经元中的功能提供帮助。Semaphorin, as a group of multifunctional proteins, plays a crucial role in the functional development of the nervous system. It not only regulates synapse formation and the growth of neurons but also participates in the regulation of the cell cycle, influences the transformation of cell morphology. Moreover, in oncology, it can affect the growth, invasion and metastasis of tumor cells and also plays a role in immune responses. Semaphorin (SEMA) is a type of secreted, membrane-bound or glycosylphosphatidylinositol-anchored glycoprotein, which is related to neural development, axon guidance, bone differentiation, the cardiovascular system and cancer, etc. Sema3F, a secreted form of the axon guidance molecules in the Semaphorin family, is involved in the development of neurons. Sema3F and its receptor neuropilin-2 are expressed in a mutually exclusive manner in the brain regions (including the olfactory bulb, hippocampus and cerebral cortex) of embryonic mice. When Sema3F acts on neurons, it can cause changes in downstream factors, including CREBBP, CREB, VEGF, etc. It can downregulate the expression of P53, affect the GABAergic system, downregulate the level of RacGTP and promote the phosphorylation of CRMP2, etc. Through the method of review, this article describes the downstream factors of Sema3F in neurons, aiming to provide assistance for the research on the functions of Sema3F in neurons.
文摘本文通过综述的形式,论述了保守轴突导向因子Semaphorins的信号蛋白Semaphorins3F (Sema3F)的在神经系统中作用的研究。基于对Sema3F的概述,我们对神经的作用进行了系统总结。在神经发育的过程中,Sema3F作为调节因子,参与皮层椎体神经元树突密度的调节及诱导树突消除和树突细胞体的回缩等多种功能。同样在对Sema3F在感觉神经中的作用的研究中,我们发现其对于嗅觉系统、视觉、内耳和牙神经等有着重要的作用。本文还探讨了Sema3F对于包括自闭症、精神分裂症和癫痫等神经系统疾病的作用。我们认为,Sema3F在神经元的发育、感觉神经以及多种神经系统疾病中均起着重要的作用。This article, in the form of a review, discusses the research on the role of the semaphorin family member Semaphorin 3F (Sema3F), a conserved axon guidance molecule, in the nervous system. Based on an overview of Sema3F, we systematically summarize its effects on neurons. During the process of neural development, Sema3F acts as a regulatory factor, participating in the modulation of dendritic density in cortical pyramidal neurons, as well as inducing dendritic elimination and retraction of dendritic cell bodies, among other functions. Similarly, in studies on the role of Sema3F in sensory neurons, we have found that it plays an important role in the olfactory system, vision, inner ear, and dental nerves. The article also explores the role of Sema3F in various neurological disorders, including autism, schizophrenia, and epilepsy. We believe that Sema3F plays a significant role in the development of neurons, sensory neurons, and a variety of neurological diseases.
基金supported by the FengYun Application Pioneering Project (Grant No. FY-APP-2022.0502)the National Natural Science Foundation of China (42205140)the State Key Laboratory of Atmospheric Environment end Extreme Meteorology (Grant No. 2024QN04)
文摘The Hyperspectral Infrared Atmospheric Sounder-II(HIRAS-II)onboard China’s FungYun(FY)-3F meteorological satellite was launched in August 2023.This study presents the first attempt to retrieve the global carbon monoxide(CO)column from HIRAS-II/FY-3F spectra based on a newly established full-physics algorithm.The CO global columns derived from the HIRAS-II/FY-3F satellite are compared to measurements from the Infrared Atmospheric Sounding Interferometer(IASI)onboard Europe’s MetopB satellite,as both satellites have the same spectral range with a similar overpass time.The correlation coefficient between the IASI/Metop-B and HIRAS-II/FY-3F CO retrievals is about 0.8.The HIRAS-II/FY-3F satellite can capture well the regions with high CO values,e.g.,Africa,North America,and East Asia.The relative difference in the CO global column between HIRAS-II and IASI is 1.2±13.7(1)%,which is within their combined retrieval uncertainty.The CO plumes from the fire emissions in North America between 18 and 23 July 2024 were observed by the HIRAS-II/FY-3F satellite and consistent with the CAMS(Copernicus Atmosphere Monitoring Service)model simulations.Our results show that the HIRAS-II/FY-3F spectra are of good enough quality to provide quantitative observations of global CO column remote sensing observations.
文摘目前在电力行业中广泛应用的SF6气体具有严重的温室效应,寻找一种绝缘性能优良的环保型替代气体成为研究热点。近年来,C3F7CN及其混合气体凭借出色的绝缘性能和环保特性得到了国内外学者的广泛关注。目前针对其放电分解机理的研究较少。首先,基于ReaxFF反应分子动力学方法和密度泛函理论,从微观层面模拟研究了C3F7CN/CO2混合气体的分解机理。基于构建的C3F7CN/CO2混合气体模型,研究了温度对C3F7CN分解过程的影响,分析了其可能的分解路径、产物类型及分布等。计算结果表明,C3F7CN在局部过热或放电等故障条件下分解容易产生CF3·、C3F7·、C·、CF3CFCN·、CF2·和F·等各类自由基,上述自由基复合将产生CF4、C2F6、C3F8、CF3CN、CO等产物。其次,利用气体绝缘试验平台和气相色谱质谱联用仪(gas chromatography mass spectrometer,GC-MS),试验分析了其多次击穿后的分解产物。试验结果表明,混合气体多次击穿后的主要分解产物是CF4、C2F6、CF3CN。这些产物分子均具有比较好的绝缘能力,保障了C3F7CN/CO2混合气体的绝缘性能不被破环。相关结论为进一步探究C3F7CN/CO2混合气体的绝缘特性及协同效应等课题提供理论依据和工程指导。
文摘为抑制白噪声和窄带干扰对局部放电脉冲信号能量测量的影响,提出了一种基于噪声参数的能量估计方法。研究了现场信号模型和信号能量谱系数的概率分布,得到噪声参数已知条件下脉冲信号能量的最大似然估计。同时为获得噪声参数,将采样数据划分成信号帧和噪声帧,采用3F–C法估计了白噪声和窄带干扰参数。通过仿真实验和实测数据处理,与传统小波包降噪方法的结果进行了对比。数据分析结果表明:无论是针对单一白噪声环境还是存在窄带干扰的混合噪声环境,该能量估计方法的准确性均优于传统小波包降噪方法,且随着信噪比的降低和信号时间窗口长度的增加,该方法表现出更明显的优势。在信噪比为–8 d B的条件下,使用该方法对实测局部放电脉冲信号进行能量估计的相对误差仅为4.07%,而使用小波包降噪方法时相对误差则达到44.12%。
