Myelin sheaths wrapping axons are key structures that help maintain the propagation speed of action potentials in both central and peripheral nervous systems(CNS and PNS).However,noninvasive,deep imaging technologies ...Myelin sheaths wrapping axons are key structures that help maintain the propagation speed of action potentials in both central and peripheral nervous systems(CNS and PNS).However,noninvasive,deep imaging technologies visualizing myelin sheaths in the digital skin in vivo are lacking in animal models.3-photon°uorescence(3PF)imaging excited at the 1700-nm window enables deep imaging of myelin sheaths,but necessitates labeling by exogenous°uorescent dyes.Since myelin sheaths are lipid-rich structures which generate strong third-harmonic signals,in this paper,we perform a detailed comparative experimental study of both third-harmonic generation(THG)and 3PF imaging in the mouse digital skin in vivo.Our results show that THG imaging also enables visualization of myelin sheaths deep in the mouse digital skin,which shows colocalization with 3PF signals from labeled myelin sheaths.Besides its superior label-free advantage,THG does not su®er from photobleaching due to its 3PF property.展开更多
Multiphoton microscopy(MPM)is a powerful imaging technology for brain research.The imaging depth in MPM is partly determined by emission wavelength of fluorescent labels.It has been demonstrated that a longer emission...Multiphoton microscopy(MPM)is a powerful imaging technology for brain research.The imaging depth in MPM is partly determined by emission wavelength of fluorescent labels.It has been demonstrated that a longer emission wavelength is favorable for signal detection as imaging depth increases.However,there has been no comparison with near-infrared(NIR)emission.In order to quantitatively analyze the effect of emission wavelength on 3-photon imaging of mouse brains in vivo,we utilize the same excitation wavelength to excite a single fluorescent dye and simultaneously collect NIR and orange-red emission fluorescence at 828 nm and 620 nm,respectively.Both experimental and simulation results show that as the imaging depth increases,NIR emission decays less than orange-red fluorescent emission.These results show that it is preferable to shift the emission wavelength to NIR to enable more e±cient signal collection deep in the brain.展开更多
The results of a series of experiments on 3-photon annihilation of positrons and electrons, including the energy-angular correlation, angular distribution, energy spectrum and linear polarization of the annihilation p...The results of a series of experiments on 3-photon annihilation of positrons and electrons, including the energy-angular correlation, angular distribution, energy spectrum and linear polarization of the annihilation photons, the method of measuring the intensities of 3-photon annihilation, and the upper limit of axion production in the triplet positronium decay, are reported.展开更多
A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence...A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence was attributed to ^5D3→^7F5, ^5D3→^7F4, ^5D3→^7F3, ^5D4→^7F6, ^5D4→^7F5, ^5D4→^7F4, and ^5D4→^7F3 transitions of Tb^3＋. The relationship between upconversion luminescence intensity and the pump power indicated that a three-photon simultaneous absorption process was dominant in this upconversion luminescence. The intense red, green, and blue upconversion luminescence of Tb^3＋-doped CaO-Al2O3-SiO2 glass may be potentially useful in developing three-dimensional display applications.展开更多
基金National Natural Science Foundation of China(NSFC)(61775143,61975126)the Science and Technology Innovation Commission of Shenzhen under(No.JCYJ20190808174819083,JCYJ20190808175201640,KQTD20150710165601017).
文摘Myelin sheaths wrapping axons are key structures that help maintain the propagation speed of action potentials in both central and peripheral nervous systems(CNS and PNS).However,noninvasive,deep imaging technologies visualizing myelin sheaths in the digital skin in vivo are lacking in animal models.3-photon°uorescence(3PF)imaging excited at the 1700-nm window enables deep imaging of myelin sheaths,but necessitates labeling by exogenous°uorescent dyes.Since myelin sheaths are lipid-rich structures which generate strong third-harmonic signals,in this paper,we perform a detailed comparative experimental study of both third-harmonic generation(THG)and 3PF imaging in the mouse digital skin in vivo.Our results show that THG imaging also enables visualization of myelin sheaths deep in the mouse digital skin,which shows colocalization with 3PF signals from labeled myelin sheaths.Besides its superior label-free advantage,THG does not su®er from photobleaching due to its 3PF property.
基金work is funded by the National Natural Sci-ence Foundation of China(Grant/Award Numbers 62075135 and 61975126)Shenzhen Science and Technology Planning Project(ZDSYS2021-0623092006020)+2 种基金Key R&D Program of Shandong Province(Grant Number 2021CXGC010202)the Science and Technology Innovation Commission of Shenzhen(Grant/Award Numbers JCYJ201908-08174819083 and JCYJ20190808175201640)and Natural Science Foundation of Shandong Province(Grant Number ZR2022MA046)Major Innovation Projects for Integrating Science,Education&Industry of Qilu University of Technology(Shan-dong Academy of Sciences,Grant Number 2022JBZ01-04).
文摘Multiphoton microscopy(MPM)is a powerful imaging technology for brain research.The imaging depth in MPM is partly determined by emission wavelength of fluorescent labels.It has been demonstrated that a longer emission wavelength is favorable for signal detection as imaging depth increases.However,there has been no comparison with near-infrared(NIR)emission.In order to quantitatively analyze the effect of emission wavelength on 3-photon imaging of mouse brains in vivo,we utilize the same excitation wavelength to excite a single fluorescent dye and simultaneously collect NIR and orange-red emission fluorescence at 828 nm and 620 nm,respectively.Both experimental and simulation results show that as the imaging depth increases,NIR emission decays less than orange-red fluorescent emission.These results show that it is preferable to shift the emission wavelength to NIR to enable more e±cient signal collection deep in the brain.
文摘The results of a series of experiments on 3-photon annihilation of positrons and electrons, including the energy-angular correlation, angular distribution, energy spectrum and linear polarization of the annihilation photons, the method of measuring the intensities of 3-photon annihilation, and the upper limit of axion production in the triplet positronium decay, are reported.
基金supported by the Education Department of Zhejiang Province (20050359)
文摘A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence was attributed to ^5D3→^7F5, ^5D3→^7F4, ^5D3→^7F3, ^5D4→^7F6, ^5D4→^7F5, ^5D4→^7F4, and ^5D4→^7F3 transitions of Tb^3＋. The relationship between upconversion luminescence intensity and the pump power indicated that a three-photon simultaneous absorption process was dominant in this upconversion luminescence. The intense red, green, and blue upconversion luminescence of Tb^3＋-doped CaO-Al2O3-SiO2 glass may be potentially useful in developing three-dimensional display applications.
