The mammalian brain is a highly complex network that consists of millions to billions of densely-interconnected neurons.Precise dissection of neural circuits at the mesoscopic level can provide important structural in...The mammalian brain is a highly complex network that consists of millions to billions of densely-interconnected neurons.Precise dissection of neural circuits at the mesoscopic level can provide important structural information for understanding the brain.Optical approaches can achieve submicron lateral resolution and achieve“optical sectioning”by a variety of means,which has the natural advantage of allowing the observation of neural circuits at the mesoscopic level.Automated whole-brain optical imaging methods based on tissue clearing or histological sectioning surpass the limitation of optical imaging depth in biological tissues and can provide delicate structural information in a large volume of tissues.Combined with various fluorescent labeling techniques,whole-brain optical imaging methods have shown great potential in the brain-wide quantitative profiling of cells,circuits,and blood vessels.In this review,we summarize the principles and implementations of various whole-brain optical imaging methods and provide some concepts regarding their future development.展开更多
The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the abso...The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the absorption spectra and the Judd-Ofelt theory, by which the radiative transition probabilities （A）, fluorescence branching ratios （β） and radiative lifetime （τ rad） were obtained. The radiative lifetimes of 5/6 and 5/7 levels in Ho3＋ （1 mol%）：LiYF4 are 10.89 and 20.19 ms, respectively, while 9.77 and 18.50 ms in Ho3＋/pr3＋ doped crystals. Hence, the τ rad of 5/7 level decreases significantly by introduction of Pr3＋ into Ho3＋：LiYF4 crystal which is beneficial to the emission of 2.9 μm. The maximum emission cross section of Ho3＋：LiYF4 crystal located at 2.05 μm calculated by McCumber theory is 0.51 ×10-20 cm2 which is compared with other crystals. The maximum emission cross section at 2948 nm in Ho3＋/pr3＋ co-doped LiYF4 crystal obtained by Fuchtbauer- Ladenburg theory is 0.68 × 10-20 cm2, and is larger than the value of 0.53 × 10-20 cm2 in Ho3＋ singly doped LiYF4 crystal. Based on the absorption and emission cross section spectra, the gain cross section spectra were calculated. In the Ho3- ions singly doped LiYF4 crystal, the gain cross sections for 2.05 μm infrared emission becomes positive once the population inversion level reaches 30%. It means that the pump threshold for obtaining 2.05 μm laser is probably lower which is an advantage for Ho3＋-doped LiYF4 2.05 μm infrared lasers. The calculated gain cross section for 2.9 μm mid-infrared emission does not become positive until the population inversion level reaches 40% in Ho3＋/pr3＋：LiYF4 crystal, but 50% in Ho3＋ singly doped LiYF4 crystal, indicating that a low pumping threshold is achieved for the H03＋：5/6 → 5/7 laser operation with the introduction of Pr3＋ ions. It was also demonstrated that Pr3＋ ion can deplete rapidly the lower laser Ho3＋：5/7 level and has influence on the Ho3＋：5/6 level. The Ho3＋/pr3＋：LiYF4 crystal may be a potential media for 2.9 μm mid-infrared laser.展开更多
We evaluate the applicability of an optical transmission measurement method commonly used for the analysis of the Black Carbon (BC) content of aerosol sample, to determine the BC content of loess sediments. A number o...We evaluate the applicability of an optical transmission measurement method commonly used for the analysis of the Black Carbon (BC) content of aerosol sample, to determine the BC content of loess sediments. A number of different sample pretreatment procedures are developed and compared, leading to an optimum preparation process. The results include: 1) Subtraction of the optical attenuation values before and after heating of the sample filters (“ΔATN”) varies linearly with the sample mass. The slope of the regression line provides the best determination of BC concentration. 2) When the sample mass is small, (NaPO3)6 pretreatment is best for BC measurement, and the BC concentration results are given by the slope of the regression between ΔATN and sample mass, for a series of samples of varying mass. 3) HF pretreatment accompanied by centrifugation and rinsing may produce a negative bias on the result. 4) Replicate measurements of BC for loess samples showed a maximum deviation less than 5.6%, suggesting that measurements of the BC concentration of a sequence of loess samples could determine variations to this degree of significance. 5) The overall trends of BC concentration in loess section sequences were similar for all chemical pretreatments. The BC concentration result for replicate samples is comparable when pretreated by the same procedure.展开更多
We used the close-coupling optical （CCO） approach to investigate the open-shell carbon atom. The elastic cross sections have been presented at the energies below 90eV, and the present CCO results have been compared ...We used the close-coupling optical （CCO） approach to investigate the open-shell carbon atom. The elastic cross sections have been presented at the energies below 90eV, and the present CCO results have been compared with other theoretical results. We found that polarization and the continuum states have significant contributions to the elastic cross sections. The present calculations show that the CCO method is capable of calculating electron scattering from open-shell atoms.展开更多
The originally published version of this paper regrettably contained some typos.First,“structure illumination microscopy”should have been written as“structured illumination microscopy”throughout the text,including...The originally published version of this paper regrettably contained some typos.First,“structure illumination microscopy”should have been written as“structured illumination microscopy”throughout the text,including in the article title,graphical abstract,the summary,and the main text.Second,in Figure 1A,“iFFT”should be written as“FFT.”Third,in Video S2,the labels“FO”and“Open”were placed incorrectly;FO is the high-quality reconstruction result,while Open contains reconstruction artifact.展开更多
Three-dimensional structured illumination microscopy(3DSIM)is a popular method for observing subcellular/cellular structures or animal/plant tissues with gentle phototoxicity and 3D super-resolution.However,its time-c...Three-dimensional structured illumination microscopy(3DSIM)is a popular method for observing subcellular/cellular structures or animal/plant tissues with gentle phototoxicity and 3D super-resolution.However,its time-consuming reconstruction process poses challenges for high-throughput imaging and real-time observation.Moreover,traditional 3DSIM typically requires more than six z layers for successful reconstruction and is susceptible to defocused backgrounds.This poses a great gap between single-layer 2DSIM and 6-layer 3DSIM,and limits the observation of thicker samples.To address these limitations,we developed FO-3DSIM,a novel method that integrates spatial-domain reconstruction with optical-sectioning SIM.FO-3DSIM enhances reconstruction speed by up to 855.7 times with superior performance with limited z layers and under high defocused backgrounds.It retains the high-fidelity,low-photon reconstruction capabilities of our previously proposed Open-3DSIM.Utilizing fast reconstruction and optical sectioning,we achieved large field-of-view(FOV)3D super-resolution imaging of mouse kidney actin,covering a region of 0.453 mm×0.453 mm×2.75μm within 23 min of acquisition and 13 min of reconstruction.Near real-time performance was demonstrated in live actin imaging with FO-3DSIM.Our approach reduces photodamage through limited z layer reconstruction,allowing the observation of ER tubes with just three layers.We anticipate that FO-3DSIM will pave the way for near real-time,large FOV 6D imaging,encompassing xyz super-resolution,multi-color,long-term,and polarization imaging with less photodamage,removed defocused backgrounds,and reduced reconstruction time.展开更多
基金supported by the STI2030-Major Projects(2021ZD0201001 and 2021ZD0201000)the National Natural Science Foundation of China(81827901 and 32192412).
文摘The mammalian brain is a highly complex network that consists of millions to billions of densely-interconnected neurons.Precise dissection of neural circuits at the mesoscopic level can provide important structural information for understanding the brain.Optical approaches can achieve submicron lateral resolution and achieve“optical sectioning”by a variety of means,which has the natural advantage of allowing the observation of neural circuits at the mesoscopic level.Automated whole-brain optical imaging methods based on tissue clearing or histological sectioning surpass the limitation of optical imaging depth in biological tissues and can provide delicate structural information in a large volume of tissues.Combined with various fluorescent labeling techniques,whole-brain optical imaging methods have shown great potential in the brain-wide quantitative profiling of cells,circuits,and blood vessels.In this review,we summarize the principles and implementations of various whole-brain optical imaging methods and provide some concepts regarding their future development.
基金supported by the National Natural Science Foundation of China(Grant Nos.51272109 and 50972061)the Natural Science Foundation of Zhejiang Province(Grant Nos.R4100364)the Natural Science Foundation of Ningbo City(Grant No.2012A610115)
文摘The LiYF4 single crystals singly doped Ho3＋ and co-doped Ho3＋, Pr3＋ ions were grown by a modified Bridgman method. The Judd-Ofelt strength parameters （Ω2, Ω4, Ω6） of No3＋ were calculated according to the absorption spectra and the Judd-Ofelt theory, by which the radiative transition probabilities （A）, fluorescence branching ratios （β） and radiative lifetime （τ rad） were obtained. The radiative lifetimes of 5/6 and 5/7 levels in Ho3＋ （1 mol%）：LiYF4 are 10.89 and 20.19 ms, respectively, while 9.77 and 18.50 ms in Ho3＋/pr3＋ doped crystals. Hence, the τ rad of 5/7 level decreases significantly by introduction of Pr3＋ into Ho3＋：LiYF4 crystal which is beneficial to the emission of 2.9 μm. The maximum emission cross section of Ho3＋：LiYF4 crystal located at 2.05 μm calculated by McCumber theory is 0.51 ×10-20 cm2 which is compared with other crystals. The maximum emission cross section at 2948 nm in Ho3＋/pr3＋ co-doped LiYF4 crystal obtained by Fuchtbauer- Ladenburg theory is 0.68 × 10-20 cm2, and is larger than the value of 0.53 × 10-20 cm2 in Ho3＋ singly doped LiYF4 crystal. Based on the absorption and emission cross section spectra, the gain cross section spectra were calculated. In the Ho3- ions singly doped LiYF4 crystal, the gain cross sections for 2.05 μm infrared emission becomes positive once the population inversion level reaches 30%. It means that the pump threshold for obtaining 2.05 μm laser is probably lower which is an advantage for Ho3＋-doped LiYF4 2.05 μm infrared lasers. The calculated gain cross section for 2.9 μm mid-infrared emission does not become positive until the population inversion level reaches 40% in Ho3＋/pr3＋：LiYF4 crystal, but 50% in Ho3＋ singly doped LiYF4 crystal, indicating that a low pumping threshold is achieved for the H03＋：5/6 → 5/7 laser operation with the introduction of Pr3＋ ions. It was also demonstrated that Pr3＋ ion can deplete rapidly the lower laser Ho3＋：5/7 level and has influence on the Ho3＋：5/6 level. The Ho3＋/pr3＋：LiYF4 crystal may be a potential media for 2.9 μm mid-infrared laser.
文摘We evaluate the applicability of an optical transmission measurement method commonly used for the analysis of the Black Carbon (BC) content of aerosol sample, to determine the BC content of loess sediments. A number of different sample pretreatment procedures are developed and compared, leading to an optimum preparation process. The results include: 1) Subtraction of the optical attenuation values before and after heating of the sample filters (“ΔATN”) varies linearly with the sample mass. The slope of the regression line provides the best determination of BC concentration. 2) When the sample mass is small, (NaPO3)6 pretreatment is best for BC measurement, and the BC concentration results are given by the slope of the regression between ΔATN and sample mass, for a series of samples of varying mass. 3) HF pretreatment accompanied by centrifugation and rinsing may produce a negative bias on the result. 4) Replicate measurements of BC for loess samples showed a maximum deviation less than 5.6%, suggesting that measurements of the BC concentration of a sequence of loess samples could determine variations to this degree of significance. 5) The overall trends of BC concentration in loess section sequences were similar for all chemical pretreatments. The BC concentration result for replicate samples is comparable when pretreated by the same procedure.
基金Project supported by the National Natural Science Foundation of China （Grant No 10274724）.
文摘We used the close-coupling optical （CCO） approach to investigate the open-shell carbon atom. The elastic cross sections have been presented at the energies below 90eV, and the present CCO results have been compared with other theoretical results. We found that polarization and the continuum states have significant contributions to the elastic cross sections. The present calculations show that the CCO method is capable of calculating electron scattering from open-shell atoms.
文摘The originally published version of this paper regrettably contained some typos.First,“structure illumination microscopy”should have been written as“structured illumination microscopy”throughout the text,including in the article title,graphical abstract,the summary,and the main text.Second,in Figure 1A,“iFFT”should be written as“FFT.”Third,in Video S2,the labels“FO”and“Open”were placed incorrectly;FO is the high-quality reconstruction result,while Open contains reconstruction artifact.
基金supported by the National Key R&D Program of China(2022YFC3401100)the National Natural Science Foundation of China(624B2009,62405010,62335008,62025501,92150301,and 62411540238).
文摘Three-dimensional structured illumination microscopy(3DSIM)is a popular method for observing subcellular/cellular structures or animal/plant tissues with gentle phototoxicity and 3D super-resolution.However,its time-consuming reconstruction process poses challenges for high-throughput imaging and real-time observation.Moreover,traditional 3DSIM typically requires more than six z layers for successful reconstruction and is susceptible to defocused backgrounds.This poses a great gap between single-layer 2DSIM and 6-layer 3DSIM,and limits the observation of thicker samples.To address these limitations,we developed FO-3DSIM,a novel method that integrates spatial-domain reconstruction with optical-sectioning SIM.FO-3DSIM enhances reconstruction speed by up to 855.7 times with superior performance with limited z layers and under high defocused backgrounds.It retains the high-fidelity,low-photon reconstruction capabilities of our previously proposed Open-3DSIM.Utilizing fast reconstruction and optical sectioning,we achieved large field-of-view(FOV)3D super-resolution imaging of mouse kidney actin,covering a region of 0.453 mm×0.453 mm×2.75μm within 23 min of acquisition and 13 min of reconstruction.Near real-time performance was demonstrated in live actin imaging with FO-3DSIM.Our approach reduces photodamage through limited z layer reconstruction,allowing the observation of ER tubes with just three layers.We anticipate that FO-3DSIM will pave the way for near real-time,large FOV 6D imaging,encompassing xyz super-resolution,multi-color,long-term,and polarization imaging with less photodamage,removed defocused backgrounds,and reduced reconstruction time.
