Biomechanical effects of posterior lumbar interbody fusion with vertical placement of pedicle screws compared to traditional placement.

BACKGROUND: The pedicle screw technique is widely employed for vertebral body fixation in the treatment of spinal disorders. However, traditional screw placement methods require the dissection of paraspinal muscles and the insertion of pedicle screws at specific transverse section angles (TSA). Larger TSA angles require more force to pull the muscle tissue, which can increase the risk of surgical trauma and ischemic injury to the lumbar muscles. AIM: To study the feasibility of zero-degree TSA vertical pedicle screw technique in the lumbosacral segment. METHODS: Finite element models of vertebral bodies and pedicle screw-rod systems were established for the L4-S1 spinal segments. A standard axial load of 500 N and a rotational torque of 10 N/m were applied. Simulated screw pull-out experiment was conducted to observe pedicle screw resistance to pull-out, maximum stress, load-displacement ratio, maximum stress in vertebral bodies, load-displacement ratio in vertebral bodies, and the stress distribution in pedicle screws and vertebral bodies. Differences between the 0-degree and 17-degree TSA were compared. RESULTS: At 0-degree TSA, the screw pull-out force decreased by 11.35% compared to that at 17-degree TSA (P < 0.05). At 0-degree and 17-degree TSA, the stress range in the screw-rod system was 335.1-657.5 MPa and 242.8-648.5 MPa, separately, which were below the fracture threshold for the screw-rod system (924 MPa). At 0-degree and 17-degree TSA, the stress range in the vertebral bodies was 68.45-78.91 MPa and 39.08-72.73 MPa, separately, which were below the typical bone yield stress range for vertebral bodies (110-125 MPa). At 0-degree TSA, the load-displacement ratio for the vertebral bodies and pedicle screws was slightly lower compared to that at 17-degree TSA, indicating slightly lower stability (P < 0.05). CONCLUSION: The safety and stability of 0-degree TSA are slightly lower, but the risks of screw-rod system fracture, vertebral body fracture, and rupture are within acceptable limits.

Multi-LiDAR human joint recognition algorithm in hospital wards based on improved V2V-Posenet.

To prevent convulsions and falls of patients in the absence of medical staff, it is crucial to monitor their physical condition in hospital wards. However, several unresolved challenges in human joint recognition remain, such as object occlusion, human self-occlusion and complex backgrounds, resulting in difficulties in its practical application. In this paper, a multi-LiDAR system is proposed to obtain a multi-view human body point cloud. An improved V2V-Posenet model was introduced to detect the actual position of the human joint. In this system, each point cloud was spliced into a full point cloud and voxelized into the model. We also used a random voxel zero setting for data enhancement, constraining the relative length between human joints into a loss function and three-dimensional Gaussian filtering in a heat map for model learning. The improved model exhibited excellent performance in detecting human joints in hospital wards. The experimental results showed that the improved model achieved 91.6 % mean average precision, compared to 80.1 % for the original model and 77.4 % for the comparison algorithm A2J-Posenet. The speed of the improved model meets the requirements for real-time target detection.

Consensus clustering and novel risk score model construction based on m6A methylation regulators to evaluate the prognosis and tumor immune microenvironment of early-stage lung adenocarcinoma.

BACKGROUND: The aim of this study was to investigate the correlation between m6A methylation regulators and cell infiltration characteristics in tumor immune microenvironment (TIME), so as to help understand the immune mechanism of early-stage lung adenocarcinoma (LUAD). METHODS: The expression and consensus cluster analyses of m6A methylation regulators in early-stage LUAD were performed. The clinicopathological features, immune cell infiltration, survival and functional enrichment in different subtypes were analyzed. We also constructed a prognostic model. Clinical tissue samples were used to validate the expression of model genes through real-time polymerase chain reaction (RT-PCR). In addition, cell scratch assay and Transwell assay were also performed. RESULTS: Expression of m6A methylation regulators was abnormal in early-stage LUAD. According to the consensus clustering of m6A methylation regulators, patients with early-stage LUAD were divided into two subtypes. Two subtypes showed different infiltration levels of immune cell and survival time. A prognostic model consisting of HNRNPC, IGF2BP1 and IGF2BP3 could be used to predict the survival of early-stage LUAD. RT-PCR results showed that HNRNPC, IGF2BP1 and IGF2BP3 were significantly up-regulated in early-stage LUAD tissues. The results of cell scratch assay and Transwell assay showed that overexpression of HNRNPC promotes the migration and invasion of NCI-H1299 cells, while knockdown HNRNPC inhibits the migration and invasion of NCI-H1299 cells. CONCLUSIONS: This work reveals that m6A methylation regulators may be potential biomarkers for prognosis in patients with early-stage LUAD. Our prognostic model may be of great value in predicting the prognosis of early-stage LUAD.

[Spatial distribution patterns and intraspecific and interspecific spatial associations of Quercus myrsinifolia population in Shennongjia, China]. / ç¥žå†œæž¶å°å¶é’å†ˆç§ç¾¤çš„ç©ºé—´åˆ†å¸ƒæ ¼å±€åŠç§å† ç§é—´ç©ºé—´å ³è”.

Quercus myrsinifolia is one of the dominant species in the evergreen broad-leaf forest on the southern slope of Shennongjia. The study of spatial distribution pattern and spatial correlation of Q. myrsinifolia population will help to understand population development and potential ecological processes, as well as the structure and biodiversity maintenance mechanism of evergreen broad-leaf forests at the northern edge of the subtropics. Based on forest dynamic monitoring data from one 1 hm2 permanent plot on the southern slope of Shennongjia, we employed pair correlation functions g(r) and marked correlation functions to analyze the diameter structure of the Q. myrsinifolia population, spatial distribution patterns at different diameter classes, and intraspecific and interspecific spatial associations. The results showed that diameter structure of Q. myrsinifolia population exhibited an inverted 'J'-shaped distribution, suggesting a healthy regeneration status and belonging to a growing population type. The spatial distribution showed a decreasing trend in aggregation with increasing diameter. Positive correlations among individuals strengthened with closer diameter classes, while weakening with larger diameter differences. Interspecific spatial associations showed an increasing correlation of Q. myrsinifolia with understory dominant species with increasing spatial scales, but no correlation was observed with canopy-dominant species. Our results suggested that the spatial pattern of Q. myrsinifolia populations on the southern slope of Shennongjia was mainly influenced by habitat filtering, seed dispersal limitation, and intraspecific and interspecific competition. Furthermore, the adaptive strategies of Q. myrsinifolia varied when they coexisted with different species.

Piezo-photocatalytic reduction of nitrates to N2 over silver dispersed on BaTiO3@TiO2.

This communication first achieved piezo-photocatalytic reduction of nitrates to N2 through designing an Ag2O/BaTiO3@TiO2 core-shell catalyst. The built-in electric field induced by piezoelectric polarization suppresses photoexcited carrier recombination, and simultaneously causes energy band tilting, leading to the generation of electrons with higher reducibility to directly trigger the NO3- reduction to ˙NO32-, even without hole scavengers.

Micro-motion characteristics of multi-feature targets on the double pulse coherent system.

In this paper, we study the micro-motion characteristics of multi-feature targets based on a double pulse coherent system under atmospheric conditions. The theoretical model for echo signal and micro-motion characteristics of a 3D target in double pulse coherent system is deduced. We discuss the influence of micro-motion characteristics, the relative size of light spot and target, target shapes, and incident direction on frequency shift. LRCS (Lidar cross-section), echo waveform, intensity and radiation energy distribution under different conditions are obtained additionally. Simulation results conclude that these parameters are of advantage to the inversion of target shape properties and motion types.

Multi-Branch Mutual-Distillation Transformer for EEG-Based Seizure Subtype Classification.

Cross-subject electroencephalogram (EEG) based seizure subtype classification is very important in precise epilepsy diagnostics. Deep learning is a promising solution, due to its ability to automatically extract latent patterns. However, it usually requires a large amount of training data, which may not always be available in clinical practice. This paper proposes Multi-Branch Mutual-Distillation (MBMD) Transformer for cross-subject EEG-based seizure subtype classification, which can be effectively trained from small labeled data. MBMD Transformer replaces all even-numbered encoder blocks of the vanilla Vision Transformer by our designed multi-branch encoder blocks. A mutual-distillation strategy is proposed to transfer knowledge between the raw EEG data and its wavelets of different frequency bands. Experiments on two public EEG datasets demonstrated that our proposed MBMD Transformer outperformed several traditional machine learning and state-of-the-art deep learning approaches. To our knowledge, this is the first work on knowledge distillation for EEG-based seizure subtype classification.

Constructing sulfur and oxygen super-coordinated main-group electrocatalysts for selective and cumulative H2O2 production.

Direct electrosynthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction presents a burgeoning alternative to the conventional energy-intensive anthraquinone process for on-site applications. Nevertheless, its adoption is currently hindered by inferior H2O2 selectivity and diminished H2O2 yield induced by consecutive H2O2 reduction or Fenton reactions. Herein, guided by theoretical calculations, we endeavor to overcome this challenge by activating a main-group Pb single-atom catalyst via a local micro-environment engineering strategy employing a sulfur and oxygen super-coordinated structure. The main-group catalyst, synthesized using a carbon dot-assisted pyrolysis technique, displays an industrial current density reaching 400 mA cm-2 and elevated accumulated H2O2 concentrations (1358 mM) with remarkable Faradaic efficiencies. Both experimental results and theoretical simulations elucidate that S and O super-coordination directs a fraction of electrons from the main-group Pb sites to the coordinated oxygen atoms, consequently optimizing the *OOH binding energy and augmenting the 2e- oxygen reduction activity. This work unveils novel avenues for mitigating the production-depletion challenge in H2O2 electrosynthesis through the rational design of main-group catalysts.

Ergothioneine and its congeners: anti-ageing mechanisms and pharmacophore biosynthesis.

Ergothioneine, Ovothiol, and Selenoneine are sulfur/selenium-containing histidine-derived natural products widely distributed across different organisms. They exhibit significant antioxidant properties, making them as potential lead compounds for promoting health. Increasing evidence suggests that Ergothioneine is positively correlated with healthy ageing and longevity. The mechanisms underlying Ergothioneine's regulation of the ageing process at cellular and molecular levels are beginning to be understood. In this review, we provide an in-depth and extensive coverage of the anti-ageing studies on Ergothioneine and discuss its possible intracellular targeting pathways. In addition, we highlight the recent efforts in elucidating the biosynthetic details for Ergothioneine, Ovothiol, and Selenoneine, with a particular focus on the study of their pharmacophore-forming enzymology.

Disentangling the role of environmental filtering and biotic resistance on alien invasions in a reservoir area.

Large-scale water conservancy projects benefit human life but have modified the landscape and provided opportunities for alien plant invasions. Understanding the environmental (e.g., climate), human-related (e.g., population density, proximity to human activities), and biotic (e.g., native plant, community structure) factors driving invasions is essential in the management of alien plants and biodiversity conservation in areas with intense human pressure. To this end, we investigated the spatial patterns of alien plant species distribution in the Three Gorges Reservoir Area (TGRA) of China and distinguished the role of the external environment and community characteristics in determining the occurrence of alien plants with differing levels of known invasion impacts in China using random forest analyses and structural equation models. A total of 102 alien plant species belonging to 30 families and 67 genera were recorded, the majority being annual and biennial herbs (65.7%). The results showed a negative diversity-invasibility relationship and supported the biotic resistance hypothesis. Moreover, percentage coverage of native plants was found to interact with native species richness and had a predominant role in resisting alien plant species. We found alien dominance was mainly the result of disturbance (e.g., changes in hydrological regime), which drove native plant loss. Our results also demonstrated that disturbance and temperature were more important for the occurrence of malignant invaders than all alien plants. Overall, our study highlights the importance of restoring diverse and productive native communities in resistance to invasion.

Impact of Elevational Gradients and Chemical Parameters on Changes in Soil Bacterial Diversity Under Semiarid Mountain Region.

Elevation gradients, often regarded as "natural experiments or laboratories", can be used to study changes in the distribution of microbial diversity related to changes in environmental conditions that typically occur over small geographical scales. We obtained bacterial sequences using MiSeq sequencing and clustered them into operational taxonomic units (OTUs). The total number of reads obtained by the bacterial 16S rRNA sequencing analysis was 1,090,555, with an average of approximately 45,439 reads per sample collected from various elevations. The current study observed inconsistent bacterial diversity patterns in samples from the lowest to highest elevations. 983 OTUs were found common among all the elevations. The most unique OTUs were found in the soil sample from elevation_2, followed by elevation_1. Soil sample collected at elevation_6 had the least unique OTUs. Actinobacteria, Protobacteria, Chloroflexi were found most abundant bacterial phyla in current study. Ammonium nitrogen (NH4+-N), and total phosphate (TP) are the main factors influencing bacterial diversity at elevations_1. pH was the main factor influencing the bacterial diversity at elevations_2, elevation_3 and elevation_4. Our results provide new visions on forming and maintaining soil microbial diversity along an elevational gradient and have implications for microbial responses to environmental change in semiarid mountain ecosystems.

Anthropogenic activities explained the difference in exotic plants invasion between protected and non-protected areas at a northern subtropics biodiversity hotspot.

Biological invasion poses a major threat to biodiversity and conservation efforts in protected areas. The Greater Shennongjia Area (GSA) is one of China's 16 key areas for biodiversity, as stated in the China National Biodiversity Conservation Strategy and Action Plan. However, the local authorities lack appropriate data on the extent and impact of exotic species in protected areas, as well as lack the capacity and motivation to properly plan for exotic species strategy and action plan to support both prevention, control as well as management of exotic plants in their jurisdiction. In addition, while most previous studies have focused on exotic species in protected areas, little effort has been devoted to specifying which environmental factors contribute to the difference between protected and non-protected areas. Here, we explored the current distribution pattern of the richness and abundance of exotic species in relation to environmental variables within the GSA. In total, we found 84 exotic plant species, of which 41 exotic species within the protected areas, in 64 genera and 27 families, predominately from Asteraceae, Fabaceae, and Poaceae. The generalized linear mixed models (GLMMs) revealed that the protection status and the distance to human settlements were the most important predictors of exotic plant richness and abundance in the GSA. Our results showed that the average exotic plant richness and coverage in the protected areas were 22% and 31% lower than outside the protected areas, respectively. Such differences were probably the result of anthropogenic activities (e.g., proximity to human settlements and the proportion of cropland). Although protected areas provide an important barrier against plant invasions, invasion may be a tricky issue for protected area management in the future. The Alliance of Protected areas in Western Hubei and Eastern Chongqing will need to further consider stringent control and management strategies for the entry of exotic species into protected areas to effectively maintain the continuity and integrity of the GSA's biodiversity and ecosystems. Our results provided guidance and support to enhance the capacity of scientific and effective management and sustainable development of the Shennongjia World Natural Heritage Site and other protected areas.

Error analysis and optimization for a full-Stokes division-of-space polarimeter.

A generalized four-channel, full-Stokes division-of-space (DoSP) error propagation model and its version with a reference optical path are presented in this paper, covering all potential error sources such as the main detector noise, intensity fluctuations, and instrument matrix error. Based on the model, a classical division-of-amplitude polarimeter (DoAmP) structure consisting of a partially polarized beam splitter (PPBS), PBS, and wave plates is thoroughly evaluated. By optimizing the PPBS and azimuth of the wave plates, several optimal parameter configurations are identified where the condition number is 1.84, and the maximum wavelength deviation range is limited to (-3.4n m, 3.62 nm), where the degree of polarization and polarized angle errors do not exceed 0.03 and 0.3°, respectively, and the instrument matrix deterioration effect is minimal enough to be disregarded. In addition to the DoAmP structure, this error propagation model can be directly extended to other arbitrary four-channel DoSP structures such as division-of-focal-plane and division-of-aperture systems, which have guidance values for system structural design, error optimization, and discovering multi-wavelength compatibility of the instrument.

Understanding oxygen evolution mechanisms by tracking charge flow at the atomic level.

Current classifications of oxygen evolution catalysts are based on energy levels of the clean catalysts. It is generally asserted that a LOM-catalyst can only follow LOM chemistry in each electron transfer step and that there can be no mixing between AEM and LOM steps without an external trigger. We use ab initio theory to track the charge flow of the water-on-catalyst system and show that the position of water orbitals is pivotal in determining whether an electron transfer step is water dominated oxidation (WDO), lattice-oxygen dominated oxidation (LoDO), or metal dominated oxidation (MDO). Microscopic photo-catalytic pathways of TiO2 (110), a material whose lattice oxygen bands lie above the metal bands, show that viable OER pathways follow either all AEM steps or mixed AEM-LOM steps. The results provide a correct description of redox chemistries at the atomic level and advance our understanding of how water-splitting catalysts produce desorbed oxygen.

Research on echo characteristics in remote detection with the pulse LiDAR of aerial targets under diverse atmospheric conditions.

This paper utilizes the idea of theoretical analysis to introduce a method for echo characteristics in remote detection with the pulse LiDAR of aerial targets under atmospheric conditions. A Missiles and an aircraft are selected as simulation targets. The relation among mutual mapping of target surface elements can be directly gained by setting light source and target parameters. We discuss influences on atmospheric transport conditions, target shapes and detection conditions on echo characteristics. Atmospheric transport model is introduced as weather conditions, including sunny and cloudy days, with or without turbulence. Simulation results conclude that the outline of scanned waveform can invert the target shape. These provide a theoretical basis for improving the target detection and tracking performance.

Universal understanding of self-healing and transformation of complex structured beams based on eigenmode superposition.

The self-healing property of laser beams with special spatial structures is of great interest. We take the Hermite-Gaussian (HG) eigenmode as an example, theoretically and experimentally investigating the self-healing and transformation characteristics of complex structured beams composed of incoherent or coherent superposition of multiple eigenmodes. It is found that a partially blocked single HG mode can recover the original structure or transfer to a lower order distribution in the far field. When the obstacle retains one pair of edged bright spots of the HG mode in each direction of two symmetry axes, the beam structure information (number of knot lines) along each axis can be restored. Otherwise, it will transfer to the corresponding low-order mode or multi-interference fringes in the far field, according to the interval of the two most-edged remaining spots. It is proved that the above effect is induced by the diffraction and interference results of the partially retained light field. This principle is also applicable to other scale-invariant structured beams such as Laguerre-Gauss (LG) beams. The self-healing and transformation characteristics of multi-eigenmode composed beams with specially customized structures can be intuitively investigated based on eigenmode superposition theory. It is found that the HG mode incoherently composed structured beams have a stronger ability to recover themselves in the far field after occlusion. These investigations can expand the applications of optical lattice structures of laser communication, atom optical capture, and optical imaging.

Complex structured beam direct generation by coherent superposition of a complete set of degenerate eigenmodes.

Structured beams have played an important role in many fields due to their rich spatial characteristics. The microchip cavity with a large Fresnel number can directly generate structured beams with complex spatial intensity distribution, which provides convenience for further exploring the formation mechanism of structured beams and realizing low-cost applications. In this article, theoretical and experimental studies are carried out on complex structured beams directly generated by the microchip cavity. It is demonstrated that the complex beams generated by the microchip cavity can be expressed by the coherent superposition of whole transverse eigenmodes within the same order, thus forming the eigenmode spectrum. The mode component analysis of complex propagation-invariant structured beams can be realized by the degenerate eigenmode spectral analysis described in this article.

Source-Free Domain Adaptation (SFDA) for Privacy-Preserving Seizure Subtype Classification.

Electroencephalogram (EEG) based seizure subtype classification is very important in clinical diagnostics. Source-free domain adaptation (SFDA) uses a pre-trained source model, instead of the source data, for privacy-preserving transfer learning. SFDA is useful in seizure subtype classification, which can protect the privacy of the source patients, while reducing the amount of labeled calibration data for a new patient. This paper introduces semi-supervised transfer boosting (SS-TrBoosting), a boosting-based SFDA approach for seizure subtype classification. We further extend it to unsupervised transfer boosting (U-TrBoosting) for unsupervised SFDA, i.e., the new patient does not need any labeled EEG data. Experiments on three public seizure datasets demonstrated that SS-TrBoosting and U-TrBoosting outperformed multiple classical and state-of-the-art machine learning approaches in cross-dataset/cross-patient seizure subtype classification.

NiO Matrix Decorated by Ru Single Atoms: Electron-Rich Ru-Induced High Activity and Selectivity toward Electrochemical N2 Reduction.

Developing a single-atom catalyst with electron-rich active sites is a promising strategy for catalyzing the electrochemical N2 reduction reaction (NRR). Herein, we choose NiO(001) as a model template and deposit a series of single transition metal (TM) atoms with higher formal charges to create the electron-rich active centers. Our first-principles calculations show that low-valent Ru (+2) on NiO(001) can significantly activate N2, with its oxidation states varying from +2 to +4 throughout the catalytic cycle. The Ru/NiO(001) catalyst exhibits the best activity with a relatively low limiting potential of -0.49 V. Furthermore, under NRR operating conditions, the Ru site is primarily occupied by *N2 rather than *H, indicating that NRR overwhelms the hydrogen evolution reaction and thus exhibits excellent selectivity. Our work highlights the potential of designing catalysts with electron-rich active sites for NRR.