We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkyn...We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.展开更多
Coherent Raman scattering(CRS)microscopy is a chemical imaging modality that provides contrast based on intrinsic biomolecular vibrations.To date,endeavors on instrumentation have advanced CRS into a powerful analytic...Coherent Raman scattering(CRS)microscopy is a chemical imaging modality that provides contrast based on intrinsic biomolecular vibrations.To date,endeavors on instrumentation have advanced CRS into a powerful analytical tool for studies of cell functions and in situ clinical diagnosis.Nevertheless,the small cross-section of Raman scattering sets up a physical boundary for the design space of a CRS system,which trades off speed,signal fidelity and spectral bandwidth.The synergistic combination of instrumentation and computational approaches offers a way to break the trade-off.In this review,we first introduce coherent Raman scattering and recent instrumentation developments,then discuss current computational CRS imaging methods,including compressive micro-spectroscopy,computational volumetric imaging,as well as machine learning algorithms that improve system performance and decipher chemical information.We foresee a constant permeation of computational concepts and algorithms to push the capability boundary of CRS microscopy.展开更多
Spectroscopic stimulated Raman scattering(SRS)imaging generates chemical maps of intrinsic molecules,with no need for prior knowledge.Despite great advances in instrumentation,the acquisition speed for a spectroscopic...Spectroscopic stimulated Raman scattering(SRS)imaging generates chemical maps of intrinsic molecules,with no need for prior knowledge.Despite great advances in instrumentation,the acquisition speed for a spectroscopic SRS image stack is fundamentally bounded by the pixel integration time.In this work,we report three-dimensional sparsely sampled spectroscopic SRS imaging that measures~20%of pixels throughout the stack.In conjunction with related work in low-rank matrix completion(e.g.,the Netflix Prize),we develop a regularized non-negative matrix factorization algorithm to decompose the sub-sampled image stack into spectral signatures and concentration maps.This design enables an acquisition speed of 0.8 s per image stack,with 50 frames in the spectral domain and 40,000 pixels in the spatial domain,which is faster than the conventional raster laser-scanning scheme by one order of magnitude.Such speed allows real-time metabolic imaging of living fungi suspended in a growth medium while effectively maintaining the spatial and spectral resolutions.This work is expected to promote broad application of matrix completion in spectroscopic laser-scanning imaging.展开更多
基金We thank the financial support from the Program for Young Talents of Shaanxi Province(5113200043)the Fundamental Research Funds for the Central Universities.
文摘We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.
文摘Coherent Raman scattering(CRS)microscopy is a chemical imaging modality that provides contrast based on intrinsic biomolecular vibrations.To date,endeavors on instrumentation have advanced CRS into a powerful analytical tool for studies of cell functions and in situ clinical diagnosis.Nevertheless,the small cross-section of Raman scattering sets up a physical boundary for the design space of a CRS system,which trades off speed,signal fidelity and spectral bandwidth.The synergistic combination of instrumentation and computational approaches offers a way to break the trade-off.In this review,we first introduce coherent Raman scattering and recent instrumentation developments,then discuss current computational CRS imaging methods,including compressive micro-spectroscopy,computational volumetric imaging,as well as machine learning algorithms that improve system performance and decipher chemical information.We foresee a constant permeation of computational concepts and algorithms to push the capability boundary of CRS microscopy.
基金supported by a Keck Foundation Science and Engineering Grant and NIH R01GM118471 grant to JXC。
文摘Spectroscopic stimulated Raman scattering(SRS)imaging generates chemical maps of intrinsic molecules,with no need for prior knowledge.Despite great advances in instrumentation,the acquisition speed for a spectroscopic SRS image stack is fundamentally bounded by the pixel integration time.In this work,we report three-dimensional sparsely sampled spectroscopic SRS imaging that measures~20%of pixels throughout the stack.In conjunction with related work in low-rank matrix completion(e.g.,the Netflix Prize),we develop a regularized non-negative matrix factorization algorithm to decompose the sub-sampled image stack into spectral signatures and concentration maps.This design enables an acquisition speed of 0.8 s per image stack,with 50 frames in the spectral domain and 40,000 pixels in the spatial domain,which is faster than the conventional raster laser-scanning scheme by one order of magnitude.Such speed allows real-time metabolic imaging of living fungi suspended in a growth medium while effectively maintaining the spatial and spectral resolutions.This work is expected to promote broad application of matrix completion in spectroscopic laser-scanning imaging.
