AIM：To determine the impact of age on the morphology of endothelial cells and central corneal thickness（CCT） in Chinese tree shrew.METHODS：One-hundred and twenty eyes of 60 healthy Chinese tree shrews were studied...AIM：To determine the impact of age on the morphology of endothelial cells and central corneal thickness（CCT） in Chinese tree shrew.METHODS：One-hundred and twenty eyes of 60 healthy Chinese tree shrews were studied.Based on age,the tree shrews were divided into four groups.After general anesthesia,the images of endothelium were acquired using non-contact specular microscope Topcon 3000 P.Eight parameters of corneal endothelial cells were measured by built-in software,including CCT,endothelial cell density（ECD）,percent hexagonality（HG%）,coeffi cient of variability（CV）,size of minimal cell（Smin）,size of maximal cell（Smax）,average cells size（Savg） and size standard deviation（Ssd）.Data were analyzed using STATA software.The differences of eight parameters among groups and correlations with age were analyzed.RESULTS：In all studied animals,the average CCT was 2 4 9.6 ± 2 .29 μ m（202-301 μm）,ECD was 308 0.72 ± 460.76 cells/mm^2（1239.6-4047.6 cells/mm^2） and CV was 29.10±7.60（13.6-54.6）.CV was significantly different among different groups（P〈0.001）.Strong correlation with age was found in ECD,Smax,Savg,Ssd and CV.CONCLUSION：Cornea of Chinese tree shrews had half CCT of human cornea and similar ECD,CV and size of corneal endothelial cells.Young adult tree shrews had higher ECD,HG% and low CV.ECD,Smax,Savg,Ssd and CV correlated with age signifi cantly.展开更多
A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring tech...A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.展开更多
Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess ...Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric,electronic,transport,and optical properties.However,the fabrication of large-scale and high-quality monolayer Pd2Se3 is still challenging.Here,we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC(0001)by a two-step epitaxial growth.The atomic structure of Pd2Se3 was investigated by scanning tunneling microscope(STM)and confirmed by non-contact atomic force microscope(nc-AFM).Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic structure.Scanning tunneling spectroscopy(STS)reveals a bandgap of 1.2 eV,suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic applications.The atomic structure and defect levels of a single Se vacancy were also investigated.The spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic behavior.The two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.展开更多
基金Supported by the Natural Science Foundation of Yunnan Province[No.2017FE467(-195)]the National Science and Technology Support Program(No.2014BAI01B01)Yunnan Joint Support for National Program(No.2015GA009)
文摘AIM：To determine the impact of age on the morphology of endothelial cells and central corneal thickness（CCT） in Chinese tree shrew.METHODS：One-hundred and twenty eyes of 60 healthy Chinese tree shrews were studied.Based on age,the tree shrews were divided into four groups.After general anesthesia,the images of endothelium were acquired using non-contact specular microscope Topcon 3000 P.Eight parameters of corneal endothelial cells were measured by built-in software,including CCT,endothelial cell density（ECD）,percent hexagonality（HG%）,coeffi cient of variability（CV）,size of minimal cell（Smin）,size of maximal cell（Smax）,average cells size（Savg） and size standard deviation（Ssd）.Data were analyzed using STATA software.The differences of eight parameters among groups and correlations with age were analyzed.RESULTS：In all studied animals,the average CCT was 2 4 9.6 ± 2 .29 μ m（202-301 μm）,ECD was 308 0.72 ± 460.76 cells/mm^2（1239.6-4047.6 cells/mm^2） and CV was 29.10±7.60（13.6-54.6）.CV was significantly different among different groups（P〈0.001）.Strong correlation with age was found in ECD,Smax,Savg,Ssd and CV.CONCLUSION：Cornea of Chinese tree shrews had half CCT of human cornea and similar ECD,CV and size of corneal endothelial cells.Young adult tree shrews had higher ECD,HG% and low CV.ECD,Smax,Savg,Ssd and CV correlated with age signifi cantly.
基金Supported by the National Natural Science Foundation of China (50605018)
文摘A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0202300,2018YFA0305800,and 2019YFA0308500)the National Natural Science Foundation of China(Grant Nos.51922011,51872284,and 61888102)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB30000000 and XDB28000000)the Science Fund from University of the Chinese Academy of Sciences.
文摘Two-dimensional(2D)materials received large amount of studies because of the enormous potential in basic science and industrial applications.Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric,electronic,transport,and optical properties.However,the fabrication of large-scale and high-quality monolayer Pd2Se3 is still challenging.Here,we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC(0001)by a two-step epitaxial growth.The atomic structure of Pd2Se3 was investigated by scanning tunneling microscope(STM)and confirmed by non-contact atomic force microscope(nc-AFM).Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic structure.Scanning tunneling spectroscopy(STS)reveals a bandgap of 1.2 eV,suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic applications.The atomic structure and defect levels of a single Se vacancy were also investigated.The spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic behavior.The two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.
