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Whole-brain mesoscale mapping in primates has been hindered by large brain sizes and the relatively low throughput of available microscopy methods. Here, we present an approach that combines primate-optimized tissue sectioning and clearing with ultrahigh-speed fluorescence microscopy implementing improved volumetric imaging with synchronized on-the-fly-scan and readout technique, and is capable of completing whole-brain imaging of a rhesus monkey at 1 × 1 × 2.5 µm3 voxel resolution within 100 h. We also developed a highly efficient method for long-range tracing of sparse axonal fibers in datasets numbering hundreds of terabytes. This pipeline, which we call serial sectioning and clearing, three-dimensional microscopy with semiautomated reconstruction and tracing (SMART), enables effective connectome-scale mapping of large primate brains. With SMART, we were able to construct a cortical projection map of the mediodorsal nucleus of the thalamus and identify distinct turning and routing patterns of individual axons in the cortical folds while approaching their arborization destinations. A whole monkey brain is imaged at high resolution in 100 hours.

Additional file 1. Supplemental material.

The speed of high-resolution optical imaging has been a rate-limiting factor for meso-scale mapping of brain structures and functional circuits, which is of fundamental importance for neuroscience research. Here, we describe a new microscopy method of Volumetric Imaging with Synchronized on-the-fly-scan and Readout (VISoR) for high-throughput, high-quality brain mapping. Combining synchronized scanning beam illumination and oblique imaging over cleared tissue sections in smooth motion, the VISoR system effectively eliminates motion blur to obtain undistorted images. By continuously imaging moving samples without stopping, the system achieves high-speed 3D image acquisition of an entire mouse brain within 1.5 hours, at a resolution capable of visualizing synaptic spines. A pipeline is developed for sample preparation, imaging, 3D image reconstruction and quantification. Our approach is compatible with immunofluorescence methods, enabling flexible cell-type specific brain mapping and is readily scalable for large biological samples such as primate brains. Using this system, we examined behaviorally relevant whole-brain neuronal activation in 16 c-Fos-shEGFP mice under resting or forced swimming conditions. Our results indicate the involvement of multiple subcortical areas in stress response. Intriguingly, neuronal activation in these areas exhibits striking individual variability among different animals, suggesting the necessity of sufficient cohort size for such studies.

The lateral load transfer rate(LTR), as a rollover index, is widely used in conventional vehicle stability control. However, the LTR cannot be applied to the articulated steering vehicles(ASV) directly due to its varying center of gravity. In this paper, considering the overall dynamic of ASV and the posture on the slope without calculating its tire deformations, we propose the avLTR as a rollover index for ASV. The validity of avLTR is verified on a 1:5 prototype driving on dangerous conditions. The experimental results show that avLTR can be used to assess the lateral stability of ASV. The avLTR is beneficial for the lateral stability control and intelligent driving of ASV.

Whole-brain mesoscale mapping of primates has been hindered by large brain size and the relatively low throughput of available microscopy methods. Here, we present an integrative approach that combines primate-optimized tissue sectioning and clearing with ultrahigh-speed, large-scale, volumetric fluorescence microscopy, capable of completing whole-brain imaging of a rhesus monkey at 1 µm × 1 µm × 2.5 µm voxel resolution within 100 hours. A progressive strategy is developed for high-efficiency, long-range tracing of individual axonal fibers through the dataset of hundreds of terabytes, establishing a “Serial sectioning and clearing, 3-dimensional Microscopy, with semi-Automated Reconstruction and Tracing” (SMART) pipeline. This system supports effective connectome-scale mapping of large primates that reveals distinct features of thalamocortical projections of the rhesus monkey brain at the level of individual axonal fibers.

During the activation and ageing, the evaporation components and rates from 4.56: 1.44: 2 impregnated dispenser cathode have been determined by the vapor-collect method based on the Auger electron spectroscopy (AES). (1) The evaporation rate of a cathode after ageing differs from that of a just activated cathode by a factor of 5 to 10. The evaporation energy of the former is 4.58 eV, and that of the latter is 4.34eV. (2) At operating temperature, the metallic barium in the evaporated materials is about 90%, and the barium oxide is about 9.3%. (3) Blow 1000°C the evaporation of Ca is not significant; over 1150°C the Ca starts evaporating rapidly, particularly in the activation process, it may approach 3.5% at 1250°C.