Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Wel...Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Well-balanced neuronal-microglial interactions are essential for brain functions.However,determining the role of microglia—the primary immune cells in the brain—in neuroinflammation in AD and the associated molecular basis has been challenging.Methods:Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed.The mechanism for microglial inflammation was investigated.IL6 and TNF-α were found to be significantly increased in the AD stage.Results:Our analysis revealed that microglia were extensively activated in AD cerebra,releasing sufficient amounts of cytokines to impair the neural stem cells(NSCs)function.Moreover,the ApoD-induced NLRC4 inflammasome was activated in microglia,which gave rise to the proinflammatory phenotype.Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis.These findings demonstrate the critical role of ApoD in microglial inflammasome activation,and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation.Conclusion:Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment.展开更多
This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle se...This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons. Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion, which is much more approximate to the light source for the practical purpose. We discuss in detail the effects of the soliton＇s velocity with some parameters in the process of transmission. The results show that by choosing special parameters, one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale.展开更多
The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the...The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast coronagraph.To solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function.The system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space.展开更多
The coherence factor of a single parameter is difficult to simultaneously improve the resolution and contrast of ultrasound images in complex imaging scenarios.Therefore,an ultrasound imaging algorithm combining optim...The coherence factor of a single parameter is difficult to simultaneously improve the resolution and contrast of ultrasound images in complex imaging scenarios.Therefore,an ultrasound imaging algorithm combining optimal apodization function and multi-parameter composite conditional factor(OA-MCCF)is proposed to improve the overall image quality.Firstly,several sets of apodization window functions are weighted on the received echo signals,and the optimal apodization function is selected based on the principle of minimizing the variance of the beamformer output.Secondly,the selected apodization function is weighted onto the echo signals to obtain the optimized array signals,and the current conditional coherence is calculated by the signals at multiple sampling times.Finally,the weighted factor is obtained by composing the conditional factors with multiple parameters according to the global image coherence information.The simulated and experimental results demonstrate that,compared with the traditional delay-and-sum algorithm,the proposed OA-MCCF algorithm can significantly enhance image resolution and contrast.Specifically,the OA-MCCF algorithm can achieve the greatest improvements in full width at half maximum of 89.23%in the point-target simulation and 63.22%in the carotid longitudinal-section experiment.Compared with the traditional coherence factor algorithm,the proposed algorithm improves resolution performance while maintaining image contrast.展开更多
在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,AP...在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,APOD)所需滤波器总电感量较大。针对以上问题,在定量分析比较PD和APOD两种调制方式谐波分布及边带谐波扩散特点的基础上,给出了两种调制方式总电感量约束方程。为保有APOD调制谐波分布集中优点的同时减小APOD总电感量需求,研究了一种基于最优三次谐波注入的改进APOD调制策略,分析了不同三次谐波注入量对APOD电压谐波分布及总电感量需求的影响,进而给出了以总电感量需求最小为目标的三次谐波最优注入量的计算方法,该方法可以实时根据当前调制度自动计算需要注入的三次谐波最优幅值,实现最优三次谐波的在线注入。最后,仿真和实验结果表明,所提策略不仅可以有效地避开高阶滤波器的谐振点,而且可有效降低主导谐波电压幅值,从而减小所需滤波器总电感量。展开更多
基金supported by the Guiding Science and Technology Development Grant in the Social Sector of Luoyang(2101083A)。
文摘Background:Alzheimer's disease(AD)is a progressive neurodegenerative disease with no effective therapies.It is well known that chronic neuroinflammation plays a critical role in the onset and progression of AD.Well-balanced neuronal-microglial interactions are essential for brain functions.However,determining the role of microglia—the primary immune cells in the brain—in neuroinflammation in AD and the associated molecular basis has been challenging.Methods:Inflammatory factors in the sera of AD patients were detected and their association with microglia activation was analyzed.The mechanism for microglial inflammation was investigated.IL6 and TNF-α were found to be significantly increased in the AD stage.Results:Our analysis revealed that microglia were extensively activated in AD cerebra,releasing sufficient amounts of cytokines to impair the neural stem cells(NSCs)function.Moreover,the ApoD-induced NLRC4 inflammasome was activated in microglia,which gave rise to the proinflammatory phenotype.Targeting the microglial ApoD promoted NSC self-renewal and inhibited neuron apoptosis.These findings demonstrate the critical role of ApoD in microglial inflammasome activation,and for the first time reveal that microglia-induced inflammation suppresses neuronal proliferation.Conclusion:Our studies establish the cellular basis for microglia activation in AD progression and shed light on cellular interactions important for AD treatment.
基金supported by the National Natural Science Foundation of China (Grant No. 60677003)
文摘This paper numerically and analytically investigates the formation and propagation motion of optical soliton in the Bragg grating. We choose the fibre Bragg grating with hyperbolic tangent apodization in the middle section in order to obtain slower solitons. Optical fibre soliton but not Bragg grating soliton is used as input pulse in the discussion, which is much more approximate to the light source for the practical purpose. We discuss in detail the effects of the soliton＇s velocity with some parameters in the process of transmission. The results show that by choosing special parameters, one can make the soliton slow-down with a little distortion and energy decay and obtain tunable time-delay on a small scale.
基金supported by the National Natural Science Foundation of China (U2031210 and 11827804)Science Research from the China Manned Space Project (CMS-CSST-2021-A11 and CMS-CSST-2021-B04).
文摘The primary mirrors of current and future large telescopes always employ a segmented mirror configuration.The small but non-negligible gaps between neighboring segments cause additional diffraction,which restricts the performance of high-contrast coronagraph.To solve this problem,we propose a coronagraph system based on a single liquid crystal spatial light modulator(SLM).This spatial light modulator is used for amplitude apodization,and its feasibility and potential performance are demonstrated using a laboratory setup using the stochastic parallel gradient descent(SPGD)algorithm to control the spatial light modulator,which is based on point spread function(PSF)sensing and evaluation and optimized for maximum contrast in the discovery working area as a merit function.The system delivers a contrast in the order of 10−6,and shows excellent potential to be used in current and future large aperture telescopes,both on the ground and in space.
基金supported by the National Natural Science Foundation of China(62071074)the Chongqing Natural Science Foundation Project(CSTB2022NSCQ-MSX0298).
文摘The coherence factor of a single parameter is difficult to simultaneously improve the resolution and contrast of ultrasound images in complex imaging scenarios.Therefore,an ultrasound imaging algorithm combining optimal apodization function and multi-parameter composite conditional factor(OA-MCCF)is proposed to improve the overall image quality.Firstly,several sets of apodization window functions are weighted on the received echo signals,and the optimal apodization function is selected based on the principle of minimizing the variance of the beamformer output.Secondly,the selected apodization function is weighted onto the echo signals to obtain the optimized array signals,and the current conditional coherence is calculated by the signals at multiple sampling times.Finally,the weighted factor is obtained by composing the conditional factors with multiple parameters according to the global image coherence information.The simulated and experimental results demonstrate that,compared with the traditional delay-and-sum algorithm,the proposed OA-MCCF algorithm can significantly enhance image resolution and contrast.Specifically,the OA-MCCF algorithm can achieve the greatest improvements in full width at half maximum of 89.23%in the point-target simulation and 63.22%in the carotid longitudinal-section experiment.Compared with the traditional coherence factor algorithm,the proposed algorithm improves resolution performance while maintaining image contrast.
文摘在采用高阶滤波器的三电平变流器中,载波同相层叠调制(phase disposition,PD)产生的开关频率次边带谐波易扩散到高阶滤波器固有谐振点附近,引起输出电流谐波增加或振荡,而载波交替反相层叠(alternative phase opposition disposition,APOD)所需滤波器总电感量较大。针对以上问题,在定量分析比较PD和APOD两种调制方式谐波分布及边带谐波扩散特点的基础上,给出了两种调制方式总电感量约束方程。为保有APOD调制谐波分布集中优点的同时减小APOD总电感量需求,研究了一种基于最优三次谐波注入的改进APOD调制策略,分析了不同三次谐波注入量对APOD电压谐波分布及总电感量需求的影响,进而给出了以总电感量需求最小为目标的三次谐波最优注入量的计算方法,该方法可以实时根据当前调制度自动计算需要注入的三次谐波最优幅值,实现最优三次谐波的在线注入。最后,仿真和实验结果表明,所提策略不仅可以有效地避开高阶滤波器的谐振点,而且可有效降低主导谐波电压幅值,从而减小所需滤波器总电感量。
