Self-Adaptive Macroscale Superlubricity Based on the Tribocatalytic Properties of Partially Oxidized Black Phosphorus.

The high-flash heat generated by direct contact at asperity tips under high contact stress and shear significantly promotes the tribocatalytic reaction between a lubricating medium and a friction interface. Macroscale superlubricity can be achieved by using additives with good lubrication properties to promote the decomposition and transformation of a lubricating medium to form an ultralow shear interface during the friction process. This paper proposed a way to achieve self-adaptive oil-based macroscale superlubricity on different tribopairs, including steel-steel and steel-DLC (diamond-like carbon), which is based on the excellent lubricating performance of black phosphorus with active oxidation and the catalytic cleavage behavior of oil molecules on the surface of oBP. This work potentially expands the industrial application of superlubricity.

Astrocyte scar formation aids central nervous system axon regeneration.

Transected axons fail to regrow in the mature central nervous system. Astrocytic scars are widely regarded as causal in this failure. Here, using three genetically targeted loss-of-function manipulations in adult mice, we show that preventing astrocyte scar formation, attenuating scar-forming astrocytes, or ablating chronic astrocytic scars all failed to result in spontaneous regrowth of transected corticospinal, sensory or serotonergic axons through severe spinal cord injury (SCI) lesions. By contrast, sustained local delivery via hydrogel depots of required axon-specific growth factors not present in SCI lesions, plus growth-activating priming injuries, stimulated robust, laminin-dependent sensory axon regrowth past scar-forming astrocytes and inhibitory molecules in SCI lesions. Preventing astrocytic scar formation significantly reduced this stimulated axon regrowth. RNA sequencing revealed that astrocytes and non-astrocyte cells in SCI lesions express multiple axon-growth-supporting molecules. Our findings show that contrary to the prevailing dogma, astrocyte scar formation aids rather than prevents central nervous system axon regeneration.

LncRNA MALAT1 inhibits hypoxia/reoxygenation-induced human umbilical vein endothelial cell injury via targeting the microRNA-320a/RAC1 axis.

Angiogenesis is believed to protect against hypoxia/reoxygenation (H/R)-induced cell injury. MALAT1 and microRNA-320a (miR-320a) are involved in cancer angiogenesis. To investigate the function of the MALAT1/miR-320a axis in H/R-induced cell injury, human umbilical vein endothelial cell (HUVEC) angiogenesis was detected using the Cell Counting Kit-8 (CCK-8), Transwell migration, cell adhesion and tube formation assays. The expression of MALAT1 and miR-320a was revealed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The direct binding relationship between miR-320a and MALAT1 was detected by RNA immunoprecipitation (RIP) and dual luciferase reporter assays. The data indicated that H/R induces angiogenesis injury and that the expression of MALAT1 was augmented in H/R-stimulated HUVECs. Overexpression of MALAT1 alleviated H/R-stimulated HUVEC dysfunction, whereas silencing of MALAT1 exerted the opposite effects. MALAT1 also reduced miR-320a levels in HUVECs. Overexpression of miR-320a repressed the function of MALAT1 on H/R-stimulated HUVECs, whereas inhibition of miR-320a exerted the opposite effect. Additionally, miR-320a inhibition alleviated H/R-stimulated HUVEC injury via RAC1. Taken together, this investigation concluded that MALAT1 represses H/R-stimulated HUVEC injury by targeting the miR-320a/RAC1 axis.

Short-Term Traffic State Prediction Based on the Spatiotemporal Features of Critical Road Sections.

Recently, short-term traffic prediction under conditions with corrupted or missing data has become a popular topic. Since a road section has predictive power regarding the adjacent roads at a specific location, this paper proposes a novel hybrid convolutional long short-term memory neural network model based on critical road sections (CRS-ConvLSTM NN) to predict the traffic evolution of global networks. The critical road sections that have the most powerful impact on the subnetwork are identified by a spatiotemporal correlation algorithm. Subsequently, the traffic speed of the critical road sections is used as the input to the ConvLSTM to predict the future traffic states of the entire network. The experimental results from a Beijing traffic network indicate that the CRS-ConvLSTM outperforms prevailing deep learning (DL) approaches for cases that consider critical road sections and the results validate the capability and generalizability of the model when predicting with different numbers of critical road sections.

Role of durotomy on function outcome, tissue sparing, inflammation, and tissue stiffness after spinal cord injury in rats.

Currently, there is a lack of effective treatments for spinal cord injury (SCI), a debilitating medical condition associated with enduring paralysis and irreversible neuronal damage. Extradural decompression of osseous as well as soft tissue components has historically been the principal objective of surgical procedures. Nevertheless, this particular surgical procedure fails to tackle the intradural compressive alterations that contribute to secondary SCI. Here, we propose an early intrathecal decompression strategy and evaluate its role on function outcome, tissue sparing, inflammation, and tissue stiffness after SCI. Durotomy surgery significantly promoted recovery of hindlimb locomotor function in an open-field test. Radiological analysis suggested that lesion size and tissue edema were significantly reduced in animals that received durotomy. Relative to the group with laminectomy alone, the animals treated with a durotomy had decreased cavitation, scar formation, and inflammatory responses at 4 weeks after SCI. An examination of the mechanical properties revealed that durotomy facilitated an expeditious restoration of the injured tissue's elastic rigidity. In general, early decompressive durotomy could serve as a significant strategy to mitigate the impairments caused by secondary injury and establish a more conducive microenvironment for prospective cellular or biomaterial transplantation.

Derivation and transcriptional reprogramming of border-forming wound repair astrocytes after spinal cord injury or stroke in mice.

Central nervous system (CNS) lesions become surrounded by neuroprotective borders of newly proliferated reactive astrocytes; however, fundamental features of these cells are poorly understood. Here we show that following spinal cord injury or stroke, 90% and 10% of border-forming astrocytes derive, respectively, from proliferating local astrocytes and oligodendrocyte progenitor cells in adult mice of both sexes. Temporal transcriptome analysis, single-nucleus RNA sequencing and immunohistochemistry show that after focal CNS injury, local mature astrocytes dedifferentiate, proliferate and become transcriptionally reprogrammed to permanently altered new states, with persisting downregulation of molecules associated with astrocyte-neuron interactions and upregulation of molecules associated with wound healing, microbial defense and interactions with stromal and immune cells. These wound repair astrocytes share morphologic and transcriptional features with perimeningeal limitans astrocytes and are the predominant source of neuroprotective borders that re-establish CNS integrity around lesions by separating neural parenchyma from stromal and immune cells as occurs throughout the healthy CNS.

Spinal cord injury: molecular mechanisms and therapeutic interventions.

Spinal cord injury (SCI) remains a severe condition with an extremely high disability rate. The challenges of SCI repair include its complex pathological mechanisms and the difficulties of neural regeneration in the central nervous system. In the past few decades, researchers have attempted to completely elucidate the pathological mechanism of SCI and identify effective strategies to promote axon regeneration and neural circuit remodeling, but the results have not been ideal. Recently, new pathological mechanisms of SCI, especially the interactions between immune and neural cell responses, have been revealed by single-cell sequencing and spatial transcriptome analysis. With the development of bioactive materials and stem cells, more attention has been focused on forming intermediate neural networks to promote neural regeneration and neural circuit reconstruction than on promoting axonal regeneration in the corticospinal tract. Furthermore, technologies to control physical parameters such as electricity, magnetism and ultrasound have been constantly innovated and applied in neural cell fate regulation. Among these advanced novel strategies and technologies, stem cell therapy, biomaterial transplantation, and electromagnetic stimulation have entered into the stage of clinical trials, and some of them have already been applied in clinical treatment. In this review, we outline the overall epidemiology and pathophysiology of SCI, expound on the latest research progress related to neural regeneration and circuit reconstruction in detail, and propose future directions for SCI repair and clinical applications.

The origins and dynamic changes of C3- and S100A10-positive reactive astrocytes after spinal cord injury.

Accaumulating studies focus on the effects of C3-positive A1-like phenotypes and S100A10-positive A2-like phenotypes of reactive astrocytes on spinal cord injury (SCI), however the origins and dynamic changes of C3- and S100A10-positive reactive astrocytes after SCI remain poorly understood. Through transgenic mice and lineage tracing, we aimed to determine the origins of C3- and S100A10-positive reactive astrocytes. Meanwhile, the distribution and dynamic changes in C3- and S100A10-positive reactive astrocytes were also detected in juvenile and adult SCI mice models and cultured astrocytes. Combing with bulk RNA sequencing (RNA-seq), single-cell RNA sequencing (scRNA-seq) and bioinformatic analysis, we further explored the dynamic transcripts changes of C3- and S100A10-positive reactive astrocytes after SCI. We confirmed that resident astrocytes produced both C3- and S100A10-positive reactive astrocytes, whereas ependymal cells regenerated only S100A10-positive reactive astrocytes in lesion area. Importantly, C3-positive reactive astrocytes were predominantly activated in adult SCI mice, while S100A10-positive reactive astrocytes were hyperactivated in juvenile mice. Furthermore, we observed that C3- and S100A10-positive reactive astrocytes had a dynamic transformation process at different time in vitro and vivo, and a majority of intermediate states of C3- and S100A10-positive reactive astrocytes were found during transformation. RNA-seq and scRNA-seq results further confirmed that the transcripts of C3-positive reactive astrocytes and their lipid toxicity were gradually increased with time and age. In contrast, S100A10-positive reactive astrocytes transcripts increased at early time and then gradually decreased after SCI. Our results provide insight into the origins and dynamic changes of C3- and S100A10-positive reactive astrocytes after SCI, which would be valuable resources to further target C3- and S100A10-positive reactive astrocytes after SCI.

Spinal cord injury-activated C/EBPß-AEP axis mediates cognitive impairment through APP C586/Tau N368 fragments spreading.

Spinal cord injury (SCI) leads to mental abnormalities such as dementia and depression; however, the molecular mechanism of SCI-induced dementia remains a matter of debate. Asparagine endopeptidase (AEP) mediated dementia by enhancing amyloid plaque and Tau hyperphosphorylation, indicating that it played an important role in neurodegeneration. Here we revealed that SCI stimulated AEP activation in mice with T9 contusion injury. Activated-AEP cleaved APP and Tau, resulting in APP C586 and Tau N368 formations, and consequentially accelerated Aß deposit and Tau hyperphosphorylation, respectively. At 9 months following injury, mice demonstrated a severe deterioration in cognitive-behavioral function, which was corroborated by the presence of accumulated AD-specific pathologies. Surprisingly, activated AEP was found in the brains of mice with spinal cord injury. In contrast, AEP knockout reduced SCI-induced neuronal death and neuroinflammation, resulting in cognitive-behavioral restoration. Interestingly, compared to the full-length proteins, truncated Tau N368 and APP C586 were easier to bind to each other. These AEP-processed fragments can not only be induced to pre-formed fibrils, but also amplified their abilities of spreading and neurotoxicity in vitro. Furthermore, as a critical transcription factor of AEP, C/EBPß was activated in injured spinal cord. Elevated C/EBPß level, as well as microglia population and inflammatory cytokines were also noticed in the cortex and hippocampus of SCI mice. These neuroinflammation pathologies were close related to the amount of Tau N368 and APP C586 in brain. Moreover, administration with the AEP-specific inhibitor, compound #11, was shown to decelerate Aß accumulation, tauopathy and C/EBPß level in both spinal cord and brain of SCI mice. Thus, this study highlights the fact that spinal cord injury is a potential risk factor for dementia, as well as the possibility that C/EBPß-AEP axis may play a role in SCI-induced cognitive impairment.

The Analysis of Classification and Spatiotemporal Distribution Characteristics of Ride-Hailing Driver's Driving Style: A Case Study in China.

Monitoring the driving styles of ride-hailing drivers is helpful for providing targeted training for drivers and improving the safety of the service. However, previous studies have lacked analyses of the temporal variation as well as spatial variation characteristics of driving styles. Understanding the variations can also help authorities formulate driver management policies. In this study, trajectory data are used to analyze driving styles in various temporal and spatial scenarios involving 34,167 drivers. The k-means method is used to cluster sample drivers. In terms of driving style time-varying, we found that only 31.79% of drivers could maintain a stable driving style throughout the day. Spatially, we divided the research area into two parts, namely, road segments and intersections, to analyze the spatial driving characteristics of drivers with different styles. The speed distribution, the acceleration and deceleration distributions are analyzed, results indicated that aggressive drivers display more aggressive driving styles in road segments, and conservative drivers exhibit more conservative driving styles at intersections. The findings of this study provide an understanding of temporal and spatial driving behavior factors for ride-hailing drivers and offer valuable contributions to ride-hailing driver training and road safety management.

MGCAF: A Novel Multigraph Cross-Attention Fusion Method for Traffic Speed Prediction.

Traffic speed prediction is an essential part of urban transportation systems that contributes to minimizing the environmental pollution caused by vehicle emissions. The existing traffic speed prediction studies have achieved good results, but some challenges remain. Most previously developed methods only account for road network characteristics such as distance while ignoring road directions and time patterns, resulting in lower traffic speed prediction accuracy. To address this issue, we propose a novel model that utilizes multigraph and cross-attention fusion (MGCAF) mechanisms for traffic speed prediction. We construct three graphs for distances, position relationships, and temporal correlations to adequately capture road network properties. Furthermore, to adaptively aggregate multigraph features, a multigraph attention mechanism is embedded into the network framework, enabling it to better connect the traffic features between the temporal and spatial domains. Experiments are performed on real-world datasets, and the results demonstrate that our method achieves positive performance and outperforms other baselines.

Exploring Influential Factors Affecting the Severity of Urban Expressway Collisions: A Study Based on Collision Data.

When traffic collisions occur on urban expressways, the consequences, including injuries, the loss of lives, and damage to properties, are more serious. However, the existing research on the severity of expressway traffic collisions has not been deeply explored. The purpose of this research was to investigate how various factors affect the severity of urban expressway collisions. The severity of urban expressway collisions was set as the dependent variable, which could be divided into three categories: slight collisions, severe collisions, and fatal collisions. Ten variables, including individual characteristics, collision characteristics, and road environment conditions, were selected as independent factors. Based on 975 valid urban expressway collisions, an ordered logistic regression model was established to evaluate the impacts of influence factors on the severity of these crashes. The results show that gender, collision modality, road pavement conditions, road surface conditions, and visibility are significant factors that affect the severity of urban expressway collisions. Females were more likely to be involved in more severe urban expressway collisions than males. For collisions involving pedestrians and non-motorized vehicles, the risk of more severe injury was 7.508 times higher than that associated with vehicle-vehicle collisions. The probability of more severe collisions on urban expressways with poor pavement conditions and wet surface conditions is greater than that on urban expressways with good pavement conditions and dry surface conditions. In addition, as visibility increases, the probability of more severe collisions on urban expressways gradually decreases. These results provide more effective strategies to reduce casualties as a result of urban expressway collisions.

Clinical and Radiographic Outcomes of Combined Posterior Transfacet Screw Fixation and Anterior Cervical Discectomy and Fusion Surgery for Unilateral Cervical Facet Fracture with Traumatic Disc Herniation: A Retrospective Cohort Study.

INTRODUCTION: Combined lateral mass screw-rod (LMSR) fixation and anterior cervical discectomy and fusion (ACDF) surgery is currently the most widely described and accepted procedure for subaxial cervical facet fracture with traumatic disc herniation. Recent biomechanical studies have demonstrated that the use of transfacet screw (TFS) can be considered as a simple alternative method to LMSR. However, to date, little is known about the feasibility and effectiveness of TFS in the combined approach. The aim of this study was to compare the clinical and radiographic results of TFS + ACDF surgery and LMSR + ACDF surgery, and to provide a less invasive alternative technique for spine surgeons. METHOD: We retrospectively reviewed patients with unilateral cervical facet fracture with traumatic disc herniation who had undergone TFS + ACDF (N = 36) or LMSR + ACDF (N = 34) with a minimum 2-year follow-up. Clinical assessments, which included American Spinal Injury Association impairment scale (AIS), visual analog scale for neck pain (VASSNP) score and patient satisfaction, were made before surgery and at follow-up. For the radiographic outcomes, the instability parameters of segmental kyphosis and sagittal translation were measured. RESULTS: The demographic characteristics of the two groups of patients were similar. In terms of clinical outcomes, both two groups were associated with significant improvements at the final follow-up. There were no significant between-group differences in VASSNP score or patient satisfaction (both P > 0.05). The LMSR + ACDF group suffered more blood loss and had longer operative time (mean 206.0 ml; mean 274.4 min, respectively) than in the TFS + ACDF group (mean 110.0 ml; mean 142.8 min, respectively) (P < 0.001 for both comparisons). For the radiographic results, the segmental kyphosis and sagittal translation were significantly corrected after surgery in both groups (P < 0.001 for both groups), and no significant differences were found between groups at the last follow-up (P > 0.05). CONCLUSION: In the absence of any self-evident clinical and radiographic benefits of one technique over the other (TFS + ACDF vs. LMSR + ACDF), we recommend combined TFS + ACDF surgery as a safe and less invasive alternative treatment for unilateral cervical facet fractures with traumatic disc herniation, as it was associated with a shorter duration of surgery and lower estimated blood loss than LMSR + ACDF surgery.

Neurogenesis potential of oligodendrocyte precursor cells from oligospheres and injured spinal cord.

Severe traumatic spinal cord injury (SCI) leads to long-lasting oligodendrocyte death and extensive demyelination in the lesion area. Oligodendrocyte progenitor cells (OPCs) are the reservoir of new mature oligodendrocytes during damaged myelin regeneration, which also have latent potential for neurogenic regeneration and oligospheres formation. Whether oligospheres derived OPCs can differentiate into neurons and the neurogenesis potential of OPCs after SCI remains unclear. In this study, primary OPCs cultures were used to generate oligospheres and detect the differentiation and neurogenesis potential of oligospheres. In vivo, SCI models of juvenile and adult mice were constructed. Combining the single-cell RNA sequencing (scRNA-seq), bulk RNA sequencing (RNA-seq), bioinformatics analysis, immunofluorescence staining, and molecular experiment, we investigated the neurogenesis potential and mechanisms of OPCs in vitro and vivo. We found that OPCs differentiation and oligodendrocyte morphology were significantly different between brain and spinal cord. Intriguingly, we identify a previously undescribed findings that OPCs were involved in oligospheres formation which could further differentiate into neuron-like cells. We also firstly detected the intermediate states of oligodendrocytes and neurons during oligospheres differentiation. Furthermore, we found that OPCs were significantly activated after SCI. Combining scRNA-seq and bulk RNA-seq data from injured spinal cord, we confirmed the neurogenesis potential of OPCs and the activation of endoplasmic reticulum stress after SCI. Inhibition of endoplasmic reticulum stress could effectively attenuate OPCs death. Additionally, we also found that endoplasmic reticulum may regulate the stemness and differentiation of oligospheres. These findings revealed the neurogenesis potential of OPCs from oligospheres and injured spinal cord, which may provide a new source and a potential target for spinal cord repair.

Temporal and spatial cellular and molecular pathological alterations with single-cell resolution in the adult spinal cord after injury.

Spinal cord injury (SCI) involves diverse injury responses in different cell types in a temporally and spatially specific manner. Here, using single-cell transcriptomic analyses combined with classic anatomical, behavioral, electrophysiological analyses, we report, with single-cell resolution, temporal molecular and cellular changes in crush-injured adult mouse spinal cord. Data revealed pathological changes of 12 different major cell types, three of which infiltrated into the spinal cord at distinct times post-injury. We discovered novel microglia and astrocyte subtypes in the uninjured spinal cord, and their dynamic conversions into additional stage-specific subtypes/states. Most dynamic changes occur at 3-days post-injury and by day-14 the second wave of microglial activation emerged, accompanied with changes in various cell types including neurons, indicative of the second round of attacks. By day-38, major cell types are still substantially deviated from uninjured states, demonstrating prolonged alterations. This study provides a comprehensive mapping of cellular/molecular pathological changes along the temporal axis after SCI, which may facilitate the development of novel therapeutic strategies, including those targeting microglia.

Anterior decompression of persistent vertebral artery occlusion caused by the cervical facet joint originated osteophyte.

BACKGROUND: Persistent vertebral artery occlusion caused by compression of cervical facet joint originated osteophyte is exceptional rare. The authors sought to achieve adequate decompression of the vertebral artery (VA) with less stability decrease and movement restriction via the anterior approach, and to the authors' knowledge, no case of anterior decompression of this condition has been reported, and combination of intraoperative indocyanine green (ICG) angiography in the setting of VA decompression is also rare. CASE PRESENTATION: A 77-year-old man presented continuous vertigo, unsteady gait and dysphagia with no relationship to the head movement. Preoperative computed tomography angiography (CTA) and digital substraction angiography (DSA) examination revealed the left vertebral artery was severely compressed at C4-5 level with approximately 95% occlusion due to a left C4-5 facet joint originated large osteophyte. Successful anterior decompression was performed without fusion and intraoperative ICG fluorescence angiography proved excellent blood flow. After surgery, vertebrobasilar insufficiency symptoms remarkably improved with no neurological deficits and no recurrence at 12 months' follow-up. CONCLUSIONS: The authors' therapeutic strategy of anterior decompression was successful in treating VA compression due to facet joint overgrowth with adequate exposure, no stability decrease and movement restriction, and lower rates of neck pain and blood loss.

Short-Term Traffic State Prediction Based on the Critical Road Selection Optimization in Transportation Networks.

Short-term traffic prediction under corrupted or missing data for large-scale transportation networks has become an important and challenging topic in recent decades. Since the critical roads have predictive power on their adjacent roads, this paper proposes a novel hybrid short-term traffic state prediction method based on critical road selection optimization. First, the utility function of the quality of service (QoS) for the critical roads in a large-scale road network is proposed based on the coverage and the data score. Then, the critical road selection optimization model in the transportation networks is presented by selecting an appropriate set of critical roads with the maximum proportion of the total calculation resources to maximize the utility value of the QoS. Also, an innovative critical road selection method is introduced, which is considering the topological structure and the mobility of the urban road network. Subsequently, the traffic speed of the critical roads is regarded as the input of the convolutional long short-term memory neural network to predict the future traffic states of the entire network. Experiment results on the Beijing traffic network indicate that the proposed method outperforms prevailing DL approaches in the case of considering critical road sections.

Immunomodulatory Layered Double Hydroxide Nanoparticles Enable Neurogenesis by Targeting Transforming Growth Factor-ß Receptor 2.

Immune microenvironment amelioration and reconstruction by functional biomaterials has become a promising strategy for spinal cord injury (SCI) recovery. In this study, we evaluated the neural regeneration and immunoregulation functions of Mg/Al layered double hydroxide (Mg/Al-LDH) nanoparticles in completely transected and excised mice and revealed the immune-related mechanisms. LDH achieved significant performance in accelerating neural stem cells (NSCs) migration, neural differentiation, L-Ca2+ channel activation, and inducible action potential generation. In vivo, the behavioral and electrophysiological performance of SCI mice was significantly improved by LDH implantation, with BrdU+ endogenous NSCs and neurons clearly observed in the lesion sites. According to RNA-seq and ingenuity pathway analysis, transforming growth factor-ß receptor 2 (TGFBR2) is the key gene through which LDH inhibits inflammatory responses and accelerates neural regeneration. Significant colocalization of TGFBR2 and LDH was found on the cell membranes of NSCs both in vitro and in vivo, and LDH increased the expression of TGF-ß2 in NSCs and activated the proliferation of precursor neural cells. LDH decreased the expression of M1 markers and increased the expression of M2 markers in both microglia and bone marrow-derived macrophages, and these effects were reversed by a TGFBR2 inhibitor. In addition, as a carrier, LDH loaded with NT3 exhibited better recovery effects with regard to the basso mouse scale score, motor evoked potential performance, and regenerated neural cell numbers than LDH itself. Thus, we have developed Mg/Al-LDH that can be used to construct a suitable immune microenvironment for SCI recovery and have revealed the targeted receptor.

How Does Cervical Sagittal Balance Change After Hangman Fracture Treated with Anterior or Posterior Approach Surgery?

OBJECTIVE: To assess and compare clinical outcomes and sagittal balance after unstable hangman fracture between C2-C3 anterior discectomy and fusion (ACDF) and posterior C2-C3 short-segment fixation and fusion. METHODS: A total of 45 patients underwent ACDF (20 patients) and posterior C2-C3 short-segment fixation and fusion (25 patients) between March 2005 and June 2013. Visual analog scale, Neck Disability Index, Odom grading system, American Spinal Injury Association Impairment Scale (AIS), C2-C3 angle, displacement of C2-C3 (DC2-C3), occiput-C2 angle (O-C2 angle), cervical lordosis (CL), and C2-C7 sagittal vertical axis (cSVA) were assessed preoperatively and at final follow-up. RESULTS: The follow-up duration was 20.0 months (range, 18.0-21.0 months) in the anterior group and 19.0 months (range, 18.0-20.0 months) in the posterior group. Satisfactory bony fusions were achieved in 2 groups. The VAS score and NDI score were significantly lower than their respective preoperative score in each group (P < 0.001), whereas there was no difference between 2 groups (P = 0.78; P = 0.85). A statistically significant decrease of O-C2 angle and cSVA between preoperative and postoperative data was found in each group (P < 0.001), and CL increased statistically (P < 0.001). For O-C2 angle, CL, and cSVA, the changes of parameters after the posterior approach were more significant than after the anterior approach (P < 0.05). CONCLUSIONS: Both anterior and posterior surgical techniques are effective for unstable hangman fracture and both can restore the sagittal balance of the cervical spine. Furthermore, the posterior approach has an advantage over the anterior approach in promoting recovery of cervical sagittal balance.

Super-Slippery Degraded Black Phosphorus/Silicon Dioxide Interface.

The interfaces between two-dimensional (2D) materials and the silicon dioxide (SiO2)/silicon (Si) substrate, generally considered as a solid-solid mechanical contact, have been especially emphasized for the structure design and the property optimization in microsystems and nanoengineering. The basic understanding of the interfacial structure and dynamics for 2D material-based systems still remains one of the inevitable challenges ahead. Here, an interfacial mobile water layer is indicated to insert into the interface of the degraded black phosphorus (BP) flake and the SiO2/Si substrate owing to the induced hydroxyl groups during the ambient degradation. A super-slippery degraded BP/SiO2 interface was observed with the interfacial shear stress (ISS) experimentally evaluated as low as 0.029 ± 0.004 MPa, being comparable to the ISS values of incommensurate rigid crystalline contacts. In-depth investigation of the interfacial structure through nuclear magnetic resonance spectroscopy and in situ X-ray photoelectron spectroscopy depth profiling revealed that the interfacial liquid water was responsible for the super-slippery BP/SiO2 interface with extremely low shear stress. This finding clarifies the strong interactions between degraded BP and water molecules, which supports the potential wider applications of the few-layer BP nanomaterial in biological lubrication.