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Serial block face scanning electron microscopy reveals novel organizational details of the retinal pigment epithelium

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Neural Regeneration Research 2022年第3期17卷 569-571页

作者： J.Arjuna Ratnayaka Eloise Keeling Clinical and Experimental Sciences Faculty of MedicineUniversity of SouthamptonSouthamptonUK

Advances in imaging have led to the development of several new types of microscopes such as serial block face scanning electron microscopy (SBF-SEM),lightsheet microscopy,as well as X-ray micro-computed tomography (mi... 详细信息

关键词： details enable scanning

A whispering-gallery scanning microprobe for Raman spectroscopy and imaging

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Light(Science & Applications) 2023年第11期12卷 2402-2410页

作者： Wenbo Mao Yihang Li Xuefeng Jiang Zhiwen Liu Lan Yang Department of Electrical and Systems Engineering Washington UniversitySt LouisMO 63130USA Department of Electrical Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA

Optical whispering-gallery-mode microsensors are a promising platform for many applications,such as biomedical monitoring,magnetic sensing,and vibration detection.However,like many other micro/nanosensors,they cannot simultaneously have two critical properties–ultrahigh sensitivity and large detection area,which are desired for most sensing applications.Here,we report a novel scanning whispering-gallery-mode microprobe optimized for both features and demonstrate enhanced Raman spectroscopy,providing high-specificity information on molecular fingerprints that are important for numerous sensing applications.Combining the superiorities of whispering-gallery modes and nanoplasmonics,the microprobe exhibits a two-orders-of-magnitude sensitivity improvement over traditional plasmonics-only enhancement;this leads to molecular detection demonstrated with stronger target signals but less optical power required than surface-enhanced-Raman-spectroscopy substrates.Furthermore,the scanning microprobe greatly expands the effective detection area and realizes two-dimensional micron-resolution Raman imaging of molecular distribution.The versatile and ultrasensitive scanning microprobe configuration will thus benefit material characterization,chemical imaging,and quantum-enhanced sensing.

关键词： microprobe scanning spectroscopy

Raster-scanning Donut simplifies MINFLUX and provides alternative implement on other scanning-based microscopes

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Light(Science & Applications) 2022年第10期11卷 2271-2275页

作者： Xinzhu Xu Shu Jia Peng Xi Department of Biomedical Engineering College of Future TechnologyPeking UniversityBeijing 100871China Wallace H.Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory UniversityAtlantaGeorgia 30332USA UTS-SUStech Joint Research Centre for Bio-medical Materials&Devices Department of Biomedical EngineeringCollege of EngineeringSouthern University of Science and TechnologyShenzhenGuangdong 518055China National Biomedical Imaging Center Peking UniversityBeijing 100871China

A donut excitation moves around a single molecule with a zigzag configuration lattice by lattice.Such a method implemented in scanning fluorescence microscopy simplifies the conventional MINFLUX process.Consisting of hollow zero-intensity excitation,single-pixel detection,time-correlated single photon counting,and drift stabilization,the system achieves localization precision and resolution very close to conventional MINFLUX theoretically and experimentally.An averaged high-SNR reference,and pixel-registered intensity from a single molecule is essential to reconstruct localization in maximum likelihood estimation.With performance reaching nearly conventional MINFLUX's,the proposed raster-scanning MINFLUX can inspire researchers expertized in STED or confocal setup to quickly transform to MINFLUX and develop for further exploring on bio-specimens or optical applications.

关键词： scanning excitation stabilization

50 years of scanning electron microscopy of bone——a comprehensive overview of the important discoveries made and insights gained into bone material properties in health,disease,and taphonomy

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Bone Research 2019年第2期7卷 123-137页

作者： Furqan A.Shah Krisztina Ruscsák Anders Palmquist Department of Biomaterials Sahlgrenska AcademyUniversity of Gothenburg

Bone is an architecturally complex system that constantly undergoes structural and functional optimisation through renewal and repair.The scanning electron microscope (SEM) is among the most frequently used instruments for examining bone.It offers the key advantage of very high spatial resolution coupled with a large depth of field and wide field of view.Interactions between incident electrons and atoms on the sample surface generate backscattered electrons,secondary electrons,and various other signals including X-rays that relay compositional and topographical information.Through selective removal or preservation of specific tissue components (organic,inorganic,cellular,vascular),their individual contribution(s) to the overall functional competence can be elucidated.With few restrictions on sample geometry and a variety of applicable sample-processing routes,a given sample may be conveniently adapted for multiple analytical methods.While a conventional SEM operates at high vacuum conditions that demand clean,dry,and electrically conductive samples,non-conductive materials (e.g.,bone) can be imaged without significant modification from the natural state using an environmental scanning electron microscope.This review highlights important insights gained into bone microstructure and pathophysiology,bone response to implanted biomaterials,elemental analysis,SEM in paleoarchaeology,3D imaging using focused ion beam techniques,correlative microscopy and in situ experiments.The capacity to image seamlessly across multiple length scales within the meso-micro-nano-continuum,the SEM lends itself to many unique and diverse applications,which attest to the versatility and user-friendly nature of this instrument for studying bone.Significant technological developments are anticipated for analysing bone using the SEM.

关键词： scanning electron microscopy comprehensive overview important discoveries

scanning tunneling microscopic observation of enhanced superconductivity in epitaxial Sn islands grown on SrTiO3 substrate

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Science Bulletin 2018年第20期63卷 1332-1337页

作者： Zhibin Shao Zongyuan Zhang Hui Yuan Haigen Sun Yan Cao Xin Zhang Shaojian Li Habakubaho Gedeon Tao Xiang Qi-Kun Xue Minghu Pan School of Physics Huazhong University of Science and TechnologyWuhan 430074China Institute of Physics Chinese Academy of ScienceBeifing 100190China Collaborative Innovation Center of Quantum Matter Beijing 100084China State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua UniversityBejiing 100084China

Recent experimental and theoretical studies of single-layer FeSe film grown on SrTiO_3 have revealed interface enhanced superconductivity, which opens up a pathway to promote the superconducting transition temperature. Here, to investigate the role of SrTiO_3 substrate in epitaxial superconducting film, we grew a conventional superconductor b-Sn(bulk T_c～ 3.72 K) onto SrTiO_3 substrate by molecular beam epitaxy. By employing scanning tunneling microscope and spectroscopic measurements, an enhanced Tcof 8.2 K is found for epitaxial b-Sn islands, deduced by fitting the temperature dependence of the gap values using the BCS formula. The observed interfacial charge injection and enhanced electron–phonon coupling are responsible for this Tcenhancement. Moreover, the critical field of 8.3 T exhibits a tremendous increase due to the suppression of the vortex formation. Therefore, the coexistence of enhanced superconductivity and high critical field of Sn islands demonstrates a feasible and effective route to improve the superconductivity by growing the islands of conventional superconductors on perovskite-type titanium oxide substrates.

关键词： Sn islands/SrTiO3 Interface-enhanced superconductivity Molecular beam epitaxy scanning tunneling microscope scanning tunneling spectroscopy

Design rules for dense and rapid Lissajous scanning

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Microsystems & Nanoengineering 2020年第1期6卷 158-164页

作者： Junya Wang Gaofei Zhang Zheng You Department of Precision Instrument Tsinghua UniversityBeijingChina State Key Laboratory of Precision Testing Technology and Instruments Tsinghua University10084 BeijingChina Information Engineering University ZhengzhouChina

Lissajous microscanners are very popular in compact laser-scanning applications,such as solid-state light detection and ranging(LIDAR),owing to their high-quality factor and low power consumption.In the Lissajous scanner driven by a two-axis micro-electro-mechanical system scanning mirror(MEMS-SM),the design theory is insufficient to meet the temporal and spatial resolution at the same time.In this paper,the greatest common divisor of the two-axis driving frequency is used as the temporal resolution,the concept of the fill factor(FF)is used to describe the spatial resolution of the scanner,and a general algorithm for calculating the FF is presented.Combined with the characteristics of the Lissajous trajectory,three design rules of the general Lissajous scanner are proposed,and the design theory of the Lissajous scanner enabling MEMS LIDAR is perfected.Experimental results show that the proposed design rules can effectively meet the LIDAR design requirements.

关键词： scanner LIDAR scanning

Ultrastructure of the gastro intestinal tract of healthy Japanese quail(Coturnix japonica) using light and scanning electron microscopy

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Animal Nutrition 2018年第4期4卷 378-387页

作者： Ngare Wilkinson Ivan Dinev William J.Aspden Robert J.Hughes Ingrid Christiansen James Chapman Sheeana Gangadoo Robert J.Moore Dragana Stanley Central Queensland University Institute for Future Farming Systems Poultry Cooperative Research Centre University of New England Armidale Faculty of Veterinary Medicine Trakia University South Australian Research and Development Institute Pig and Poultry Production Institute School of Animal and Veterinary Sciences University of Adelaide School of Science RMIT University Department of Microbiology Monash University

The Japanese quail(Coturnix japonica) are popular both as an alternative protein source and as a model of choice for scientific research in several disciplines. There is limited published information on the histological features of the intestinal tract of Japanese quail. The only comprehensive reference is a book published in 1969. This study aims to fill that niche by providing a reference of general histological features of the Japanese quail, covering all the main sections of the intestinal tract. Both light and scanning electron microscope(SEM) images are presented. Results showed that the Japanese quail intestinal tract is very similar to that of the chicken with the exception of the luminal koilin membrane of the gizzard. scanning electron microscopic photomicrographs show that in the Japanese quail koilin vertical rods are tightly packed together in a uniform manner making a carpet-like appearance. This differs in chicken where the conformations of vertical rods are arranged in clusters.

关键词： Japanese quail Coturnix japonica Histology Microscopy scanning electron microscopy Gastrointestinal tract

scanning Mode Application of Neutron-Gamma Analysis for Soil Carbon Mapping

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Pedosphere 2019年第3期29卷 334-343页

作者： Aleksandr KAVETSKIY Galina YAKUBOVA Nikolay SARGSYAN Clyde WIKLE Stephen A. PRIOR Henry Allen TORBERT Bryan A. CHIN United States Department of Agriculture-Agricultural Research Service (USDA-ARS) National Soil Dynamics Laboratory Auburn AL 36832 (USA) Auburn University Detection and Food Safety Center Samuel Ginn College of Engineering Auburn AL 36849 (USA)

Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A Global Positioning System(GPS) device and softwares required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from static mode. The error analysis indicated that scanning measurements can be conducted with the same accuracy as static measurements in approximately one fourth the time. To obtain results suitable for mapping analogous to traditional chemical analyses(i.e.,± 0.5 in weight percent or ± 0.5 w%), scanning time over a given site should be ca. 15 min using the current measurement system configuration. Based on this measurement time, a reasonable towing speed of 3–5 km h^-1, the necessity for complete site coverage during scanning, the number of sites(within the surveyed field), and the required total measurement time can be estimated. Soil carbon measurements for 28 field sites(total area ca. 2.5 ha) were conducted in ca. 8 h. Based on acquired data,a soil carbon distribution map was constructed utilizing various softwares. The surveyed field area included an asphalt road that had carbon readings higher than the surrounding land. The clarity with which these carbon-rich zones were delineated on the constructed map represents evidence supporting the veracity of this method. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps.

关键词： ArcGIS Google Earth Pro IGOR scanning technology soil carbon distribution map soil carbon storage

Application of laser scanning for rock mass characterization and discrete fracture network generation in an underground limestone mine

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International Journal of Mining Science and Technology 2019年第1期29卷 131-137页

作者： Juan J.Monsalve Jon Baggett Richard Bishop Nino Ripepi Mining and Minerals Department Virginia Polytechnic Institute&State University

Terrestrial laser scanning(TLS) is a useful technology for rock mass characterization. A laser scanner produces a massive point cloud of a scanned area, such as an exposed rock surface in an underground tunnel,with millimeter precision. The density of the point cloud depends on several parameters from both the TLS operational conditions and the specifications of the project, such as the resolution and the quality of the laser scan, the section of the tunnel, the distance between scanning stations, and the purpose of the scans. One purpose of the scan can be to characterize the rock mass and statistically analyze the discontinuities that compose it for further discontinuous modeling. In these instances, additional data processing and a detailed analysis should be performed on the point cloud to extract the parameters to define a discrete fracture network(DFN) for each discontinuity set. I-site studio is a point cloud processing software that allows users to edit and process laser scans. This software contains a set of geotechnical analysis tools that assist engineers during the structural mapping process, allowing for greater and more representative data regarding the structural information of the rock mass, which may be used for generating DFNs. This paper presents the procedures used during a laser scan for characterizing discontinuities in an underground limestone mine and the results of the scan as applied to the generation of DFNs for further discontinuous modeling.

关键词： Rock mass characterization Laser scanning Discrete fracture network I-site studio