Independent component analysis was applied to analyze the acoustic signals from diesel engine. First the basic prin-ciple of independent component analysis (ICA) was reviewed. Diesel engine acoustic signal was decompo...Independent component analysis was applied to analyze the acoustic signals from diesel engine. First the basic prin-ciple of independent component analysis (ICA) was reviewed. Diesel engine acoustic signal was decomposed into several inde-pendent components (ICs); Fourier transform and continuous wavelet transform (CWT) were applied to analyze the independent components. Different noise sources of the diesel engine were separated, based on the characteristics of different component in time-frequency domain.展开更多
An approach was proposed for optimizing beamforming that was based on Support Vector Regression (SVR). After studying the mathematical principal of the SVR algorithm and its primal cost function, the modified cost fun...An approach was proposed for optimizing beamforming that was based on Support Vector Regression (SVR). After studying the mathematical principal of the SVR algorithm and its primal cost function, the modified cost function was first applied to uniform array beamforming, and then the corresponding parameters of the beamforming were optimized. The framework of SVR uniform array beamforming was then established. Simulation results show that SVR beamforming can not only approximate the performance of conventional beamforming in the area without noise and with small data sets, but also improve the generalization ability and reduce the computation burden. Also, the side lobe level of both linear and circular arrays by the SVR algorithm is improved sharply through comparison with the conventional one. SVR beamforming is superior to the conventional method in both linear and circular arrays, under single source or double non-coherent sources.展开更多
Objective: Reactive oxygen species(ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but diffi...Objective: Reactive oxygen species(ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli. Methods: Modified microfluidics and imaging techniques were used to determine O2·- levels and construct an O2^·- reaction network. To elucidate the consequences of increased O2^·- input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca2+ levels, mitochondrial Ca^2+ uptake, auto-amplification of intracellular ROS and the intrinsic apoptotic pathway. Results and conclusions: Results from a modified microchip demonstrated that 1 mmol/L H·-2 O2 induced a rapid increase in cellular O2 levels(>27 vs.>406 amol in 20 min), leading to increased cellular oxidizing power(evaluated by ROS levels) and decreased reducing power(evaluated by glutathione(GSH) levels). In addition, we examined the dynamics of cytosolic Ca^2+ and mitochondrial Ca^2+ by confocal laser scanning microscopy and confirmed that Ca^2+ stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca^2+ bursts. It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate. The stress response involves the transfer of Ca^2+ signals between organelles,ROS auto-amplification, mitochondrial dysfunction, and a caspase-dependent apoptotic pathway.展开更多
As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can b...As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.展开更多
基金Project (No. 50575203) supported by the National Natural ScienceFoundation of China
文摘Independent component analysis was applied to analyze the acoustic signals from diesel engine. First the basic prin-ciple of independent component analysis (ICA) was reviewed. Diesel engine acoustic signal was decomposed into several inde-pendent components (ICs); Fourier transform and continuous wavelet transform (CWT) were applied to analyze the independent components. Different noise sources of the diesel engine were separated, based on the characteristics of different component in time-frequency domain.
基金the Foundation of Returned Scholar of Shaanxi Province(SLZ2008006)
文摘An approach was proposed for optimizing beamforming that was based on Support Vector Regression (SVR). After studying the mathematical principal of the SVR algorithm and its primal cost function, the modified cost function was first applied to uniform array beamforming, and then the corresponding parameters of the beamforming were optimized. The framework of SVR uniform array beamforming was then established. Simulation results show that SVR beamforming can not only approximate the performance of conventional beamforming in the area without noise and with small data sets, but also improve the generalization ability and reduce the computation burden. Also, the side lobe level of both linear and circular arrays by the SVR algorithm is improved sharply through comparison with the conventional one. SVR beamforming is superior to the conventional method in both linear and circular arrays, under single source or double non-coherent sources.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(No.LY18H300002)the Medical Health Science and Technology Project of Zhejiang Provincial Health Commission(No.2019RC061/2019312897)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(Nos.Y4110212 and LY19H090001)partly by the National Natural Science Foundation of China(Nos.81372301 and 81301113)
文摘Objective: Reactive oxygen species(ROS) are involved in a variety of biological phenomena and serve both deleterious and beneficial roles. ROS quantification and assessment of reaction networks are desirable but difficult because of their short half-life and high reactivity. Here, we describe a pro-oxidative model in a single human lung carcinoma SPC-A-1 cell that was created by application of extracellular H2O2 stimuli. Methods: Modified microfluidics and imaging techniques were used to determine O2·- levels and construct an O2^·- reaction network. To elucidate the consequences of increased O2^·- input, the mitochondria were given a central role in the oxidative stress mode, by manipulating mitochondria-interrelated cytosolic Ca2+ levels, mitochondrial Ca^2+ uptake, auto-amplification of intracellular ROS and the intrinsic apoptotic pathway. Results and conclusions: Results from a modified microchip demonstrated that 1 mmol/L H·-2 O2 induced a rapid increase in cellular O2 levels(>27 vs.>406 amol in 20 min), leading to increased cellular oxidizing power(evaluated by ROS levels) and decreased reducing power(evaluated by glutathione(GSH) levels). In addition, we examined the dynamics of cytosolic Ca^2+ and mitochondrial Ca^2+ by confocal laser scanning microscopy and confirmed that Ca^2+ stores in the endoplasmic reticulum were the primary source of H2O2-induced cytosolic Ca^2+ bursts. It is clear that mitochondria have pivotal roles in determining how exogenous oxidative stress affects cell fate. The stress response involves the transfer of Ca^2+ signals between organelles,ROS auto-amplification, mitochondrial dysfunction, and a caspase-dependent apoptotic pathway.
基金supported by the National Natural Science Foundation of China(Grant No.30670791)the National Basic Research Program of China(Grant No.2009CB918301)+1 种基金the National High Technology Research and Development Program of China(Grant No.2008AA02Z124)the State Key Laboratory of Proteomics(Grant No.SKLP-Y200810)
文摘As a pivotal signal pathway,the Ras/Raf/MEK/ERK cascade can be activated by multiple extracellular stimuli and can transmit signals to diverse substrates.It remains to be elucidated how so many different signals can be variously transferred by only two MEK molecules(MEK1 and MEK2) .Because of technological limitations the complete structures of the MEKs are still unavailable.Here,we report the full-length structure of MEK2 obtained by homology modeling and molecular dynamics simulations.The simulations show that the N-terminal part of MEK2 is highly flexible and this flexibility may enable MEK2 to interact with ERKs and other ligands in diverse manners that correspond to various upstream signals and downstream consequences.
