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BACKGROUND: Although many molecules have been investigated as biomarkers for spinal cord injury (SCI) or ischemic stroke, none of them are specifically induced in central nervous system (CNS) neurons following injuries with low baseline expression. However, neuronal injury constitutes a major pathology associated with SCI or stroke and strongly correlates with neurological outcomes. Biomarkers characterized by low baseline expression and specific induction in neurons post-injury are likely to better correlate with injury severity and recovery, demonstrating higher sensitivity and specificity for CNS injuries compared to non-neuronal markers or pan-neuronal markers with constitutive expressions. METHODS: In animal studies, young adult wildtype and global Atf3 knockout mice underwent unilateral cervical 5 (C5) SCI or permanent distal middle cerebral artery occlusion (pMCAO). Gene expression was assessed using RNA-sequencing and qRT-PCR, while protein expression was detected through immunostaining. Serum ATF3 levels in animal models and clinical human samples were measured using commercially available enzyme-linked immune-sorbent assay (ELISA) kits. RESULTS: Activating transcription factor 3 (ATF3), a molecular marker for injured dorsal root ganglion sensory neurons in the peripheral nervous system, was not expressed in spinal cord or cortex of naïve mice but was induced specifically in neurons of the spinal cord or cortex within 1 day after SCI or ischemic stroke, respectively. Additionally, ATF3 protein levels in mouse blood significantly increased 1 day after SCI or ischemic stroke. Importantly, ATF3 protein levels in human serum were elevated in clinical patients within 24 hours after SCI or ischemic stroke. Moreover, Atf3 knockout mice, compared to the wildtype mice, exhibited worse neurological outcomes and larger damage regions after SCI or ischemic stroke, indicating that ATF3 has a neuroprotective function. CONCLUSIONS: ATF3 is an easily measurable, neuron-specific biomarker for clinical SCI and ischemic stroke, with neuroprotective properties. HIGHLIGHTS: ATF3 was induced specifically in neurons of the spinal cord or cortex within 1 day after SCI or ischemic stroke, respectively. Serum ATF3 protein levels are elevated in clinical patients within 24 hours after SCI or ischemic stroke. ATF3 exhibits neuroprotective properties, as evidenced by the worse neurological outcomes and larger damage regions observed in Atf3 knockout mice compared to wildtype mice following SCI or ischemic stroke.

The start-up of a high temperature heat pipe is a complex multi-phase transition and flow heat transfer process, which may result in heat transfer oscillations, causing fluctuations in the heat pipe temperature and thus affecting the operational safety of the reactor. In this study, for the high temperature sodium heat pipe with a length of 1 000 mm and a diameter of 20 mm, the evolution law of the heat transfer oscillation was summarized through start-up experiments under vertical and horizontal conditions. The finite element thermal-mechanical simulation and thermal fatigue program analysis of a localized heat pipe reactor core design with generalized characteristics were carried out, and the stress response and the consequences of fatigue damage induced by heat pipe heat transfer oscillations were investigated. The experimental results show that the change of sodium evaporation rate causes the change of heat pipe pressure under vertical condition, which affects the evaporation and reflux balance of working medium, and causes the oscillation of heat transfer in different characteristics during start-up process. Enhancing the input power will shorten the frequency and decrease the amplitude of the oscillation. When the heat flow density increases from 9 973.71 W/m2 to 12 452.28 W/m2, the temperature oscillation amplitude decreases by nearly 30% and the oscillation period is shortened by about 40%. In the heat transfer oscillation state, the heat pipe will still maintain the heat transfer oscillation when the input power is suddenly reduced, but the waveform changes from a sawtooth shape to a trapezoid shape. The oscillation is obviously suppressed under horizontal condition. Simulation results show that, when the high temperature heat pipe heat transfer oscillation occurs, the thermal fatigue failure risk area of the localized reactor core is the inner wall of the evaporation section of the heat pipe. Fatigue damage is the largest in same-phase oscillation. The average value of the stress increases when the peak temperature difference increases due to the phase difference of oscillation, but because the decrease in the amplitude of stress of different-phase condition, the fatigue damage is reduced compared to the same-phase condition. Considering the effect of the conservatism deviation and creep on the fatigue damage, the thermal fatigue analysis is based on the safety factor K. Fatigue safety analysis results show that when the safety factor K is lower than 1.4 there is almost no risk of fatigue failure. K reaches 1.4 or more fatigue damage is gradually significant. When K=1.6 the fatigue life of the pipe wall material reduces to 3.29 years. This study is of great significance in analyzing the mechanism of heat transfer oscillation of high temperature sodium heat pipe and improving the reliability assessment of heat pipe.

Chronic pain remains a public health problem and contributes to the ongoing opioid epidemic. Current pain management therapies still leave many patients with poorly controlled pain, thus new or improved treatments are desperately needed. One major challenge in pain research is the translation of preclinical findings into effective clinical practice. The local neuroimmune interface plays an important role in the initiation and maintenance of chronic pain and is therefore a promising target for novel therapeutic development. Neurons interface with immune and immunocompetent cells in many distinct microenvironments along the nociceptive circuitry. The local neuroimmune interface can modulate the activity and property of the neurons to affect peripheral and central sensitization. In this review, we highlight a specific subset of many neuroimmune interfaces. In the central nervous system, we examine the interface between neurons and microglia, astrocytes, and T lymphocytes. In the periphery, we profile the interface between neurons in the dorsal root ganglion with T lymphocytes, satellite glial cells, and macrophages. To bridge the gap between preclinical research and clinical practice, we review the preclinical studies of each neuroimmune interface, discuss current clinical treatments in pain medicine that may exert its action at the neuroimmune interface, and highlight opportunities for future clinical research efforts.

Due to the advantages of long service life, compact structure, strong environmental adaptability and high inherent safety, the heat pipe reactor power supply system is worth studying. The NUSTER2.0 dual-mode heat pipe reactor non-nuclear prototype built by Xi’an Jiaotong University adopts the integrated design of “simulated reactor core-high temperature heat pipe-Stirling generator-thermoelectric power generation”. The combination of the dynamic module coupled with Stirling and the static module coupled with thermoelectric power generation device can meet the diversified demands of energy. In this paper, the steady-state experiment of NUSTER2.0 was carried out to verify the design, and the system coupling simulation of the prototype was carried out by COMSOL multiphysics to analyze its operation and mechanical characteristics. In the 15 kW thermal power steady-state experiment, the generating power of the dynamic module is 2 019 W, and the static module is 493.2 W. The overall thermoelectric conversion efficiency is 16.7%, which verifies the engineering feasibility of the design. The system simulation model is coupled with the thermal resistance network model of high temperature heat pipe, the equivalent thermal conductivity model of thermoelectric power generation device and the Stirling adiabatic analysis program. The heat source of fuel rod and the heat sink of cooling water were simulated by heat flux boundary and convective boundary respectively. Under 15 kW thermal power, the steady-state simulation results are in good agreement with the experimental results on both the heat pipe temperature distribution and the main operating parameters of the dynamic and static modules, while the maximum relative error is 6.73%, which verifies that the coupled model is reliable. The variable thermal power steady-state simulation determines that the limit due to Stirling is 16.5 kW, and predicts that the static module will reach the peak efficiency near 25 kW. The system start-up transient simulation obtains the start-up characteristics under the 3.5-10.15 kW stepped power platform. The prototype start-up strategy based on the combination of power platform cold start and thermal insulation restart was also proposed. The thermal-mechanical coupling simulation indicates that the stress danger zone of the system is the coupling between the heat pipe and assembly matrix. Under 15 kW thermal power, the maximum stress at the coupling of heat pipe-core matrix and heat pipe-collector matrix are 160 MPa and 97 MPa, respectively. In the experiment, the self-adjusting function of the Stirling insulation ring can significantly relieve the 366 MPa stress between it and the Stirling matrix. The thermal expansion rate of the reactor core is 1.21%, which will cause negative feedback on the reactivity. The simulation results provide the numerical basis for the operation safety analysis and further experimental design of the NUSTER2.0 prototype.

In recent years, with the rapid development of unmanned aerial vehicle (UAV) technology, multi-view 3D reconstruction has once again become a hot spot in computer vision. Incremental Structure From Motion (SFM) is currently the most prevalent reconstruction pipeline, but it still faces challenges in reconstruction efficiency, accuracy, and feature matching. In this paper, we use deep learning algorithms for feature matching to obtain more accurate matching point pairs. Moreover, we adopted the improved Gauss–Newton (GN) method, which not only avoids numerical divergence but also accelerates the speed of bundle adjustment (BA). Then, the sparse point cloud reconstructed by SFM and the original image are used as the input of the depth estimation network to predict the depth map of each image. Finally, the depth map is fused to complete the reconstruction of dense point clouds. After experimental verification, the reconstructed dense point clouds have rich details and clear textures, and the integrity, overall accuracy, and reconstruction efficiency of the point clouds have been improved. [ABSTRACT FROM AUTHOR]