238 research outputs found
System Reliability Evaluation Based on Convex Combination Considering Operation and Maintenance Strategy
The approaches to the system reliability evaluation with respect to the cases, where the components are independent or the components have interactive relationships within the system, were proposed in this paper. Starting from the higher requirements on system operational safety and economy, the reliability focused optimal models of multiobjective maintenance strategies were built. For safety-critical systems, the pessimistic maintenance strategies are usually taken, and, in these cases, the system reliability evaluation has also to be tackled pessimistically. For safety-uncritical systems, the optimistic maintenance strategies were usually taken, and, in these circumstances, the system reliability evaluation had also to be tackled optimistically, respectively. Besides, the reasonable maintenance strategies and their corresponding reliability evaluation can be obtained through the convex combination of the above two cases. With a high-speed train system as the example background, the proposed method is verified by combining the actual failure data with the maintenance data. Results demonstrate that the proposed study can provide a new system reliability calculation method and solution to select and optimize the multiobjective operational strategies with the considerations of system safety and economical requirements. The theoretical basis is also provided for scientifically estimating the reliability of a high-speed train system and formulating reasonable maintenance strategies
SCOREH+: A High-Order Node Proximity Spectral Clustering on Ratios-of-Eigenvectors Algorithm for Community Detection
The research on complex networks has achieved significant progress in
revealing the mesoscopic features of networks. Community detection is an
important aspect of understanding real-world complex systems. We present in
this paper a High-order node proximity Spectral Clustering on
Ratios-of-Eigenvectors (SCOREH+) algorithm for locating communities in complex
networks. The algorithm improves SCORE and SCORE+ and preserves high-order
transitivity information of the network affinity matrix. We optimize the
high-order proximity matrix from the initial affinity matrix using the Radial
Basis Functions (RBFs) and Katz index. In addition to the optimization of the
Laplacian matrix, we implement a procedure that joins an additional eigenvector
(the leading eigenvector) to the spectrum domain for clustering if
the network is considered to be a "weak signal" graph. The algorithm has been
successfully applied to both real-world and synthetic data sets. The proposed
algorithm is compared with state-of-art algorithms, such as ASE, Louvain,
Fast-Greedy, Spectral Clustering (SC), SCORE, and SCORE+. To demonstrate the
high efficacy of the proposed method, we conducted comparison experiments on
eleven real-world networks and a number of synthetic networks with noise. The
experimental results in most of these networks demonstrate that SCOREH+
outperforms the baseline methods. Moreover, by tuning the RBFs and their
shaping parameters, we may generate state-of-the-art community structures on
all real-world networks and even on noisy synthetic networks
Analysis of the Clinical Characteristics of Malignant Tumor Patients with Rheumatic Symptoms and Rheumatic Disease Combined with Malignant Tumor Patients
Objective: We study the relationship between rheumatic immune disease and malignant tumor to provide the basis for clinical diagnosis and treatment. Methods: We selected 53 patients who were hospitalized in our department from January 2013 to February 2020, including 26 patients with rheumatic immune disease combined with malignant tumor and 27 patients with malignant tumor with rheumatic symptoms. We retrospectively analyzed the relationship between gender, age, main clinical manifestations, tumor system distribution, metastasis rate, rheumatic immune disease type and tumor type. Results: Among the patients with rheumatic immune disease complicated with tumor, 26.1% were male and 66.7% were female. Among the tumor patients with rheumatic symptoms, 73.9% were male and 33.3% were female. There was a significant difference in gender composition between the two groups. Among the patients with rheumatic immune disease complicated with tumor, respiratory system tumor was the highest. Among the tumor patients with rheumatic symptoms, the incidence of hematological tumors was the highest. The distribution of tumor system was different between the two groups. The proportion of metastatic tumor in patients with rheumatic symptoms is higher than that in patients with rheumatic immune disease combined with malignant tumor. The percentage of concurrent tumor in three diseases in the same period was 0.363% for rheumatoid arthritis, 2.02% for polymyositis/ dermatomyositis and 0.24% for Sjogren's syndrome. This study shows that patients with polymyositis/ dermatomyositis are more likely to develop malignant tumors. Conclusion: There were significant differences in gender composition, distribution of tumor system and the proportion of metastatic tumor between patients with rheumatic immune disease complicated with malignant tumor and patients with rheumatic symptoms, and malignant tumor was more common in patients with polymyositis/ dermatomyositis
Reliability Model Construction for Complex System Based on Common Cause Failure Network
A new construction method of system reliability was proposed in this paper based on network and relevant failure. Taking the component units as the nodes and the interaction relationships between the nodes as the side lines, a new directional network reliability model with certain network topology characteristics was constructed. It can indicate the complex topology relationship, interaction mechanism, and the transmission mechanism of failure affect between mechanical integration and electrical integration of system components. Compared with the traditional research methods, the relevant failure was considered during this process. Through the application of the fault data in the bogie system of high-speed train, it was shown that a new network reliability model which considered the relevant failure can be constructed by the method proposed in this paper and the result can be more accurate, especially for the complex mechanical and electrical integration systems
Effect of amber powder on endometrial ultrastructure and MAPK pathway in endometriosis model rats
Purpose: To explore the therapeutic role of amber powder in endometriosis by investigating its effect on endometrial ultrastructure, ERK1/2, p38MAPK, and NF-κB mRNA pathways and CSRC/EFR/ERK1/2 proteins.
Methods: Sprague Dawley (SD) rats were randomly divided into blank group, disease model group (untreated), amber powder high-dose group, amber powder medium-dose group, amber powder lowdose group and danazol group. Morphological changes in endometrial cells were studied using transmission electron microscopy. The expression of ERK1/2, p38MAPK, and NF-κB mRNA in endometrial tissues of each group was determined using quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry was utilized for the measurement of C-SRC/EFR/ERK1/2 pathway protein expression.
Results: The endometriosis rats treated with a high-, medium- and low-dose amber powder showed a decrease in the volume of ectopic lesions, compared with the untreated disease model group. The expressions of ERK1/2, p38MAPK, NF-κB mRNA, and C-SRC/EFR/ERK1/2 protein were higher in the eutopic and ectopic endometrial tissues in untreated disease group than those in normal control group. Moreover, treatment of endometriosis rats with amber powder revealed a reduction in the expressions of ERK1/2, p38MAPK, NF-κB mRNA and C-SRC/EFR/ERK1/2 proteins in eutopic and ectopic endometrium tissues.
Conclusion: Amber powder reduces ectopic lesions and slows down the development of endometriosis, probably via inhibition of MAPK pathway genes in eutopic and ectopic endometrial tissues
Panacea: Panoramic and Controllable Video Generation for Autonomous Driving
The field of autonomous driving increasingly demands high-quality annotated
training data. In this paper, we propose Panacea, an innovative approach to
generate panoramic and controllable videos in driving scenarios, capable of
yielding an unlimited numbers of diverse, annotated samples pivotal for
autonomous driving advancements. Panacea addresses two critical challenges:
'Consistency' and 'Controllability.' Consistency ensures temporal and
cross-view coherence, while Controllability ensures the alignment of generated
content with corresponding annotations. Our approach integrates a novel 4D
attention and a two-stage generation pipeline to maintain coherence,
supplemented by the ControlNet framework for meticulous control by the
Bird's-Eye-View (BEV) layouts. Extensive qualitative and quantitative
evaluations of Panacea on the nuScenes dataset prove its effectiveness in
generating high-quality multi-view driving-scene videos. This work notably
propels the field of autonomous driving by effectively augmenting the training
dataset used for advanced BEV perception techniques.Comment: Project page: https://panacea-ad.github.io
Aberrant Brain Regional Homogeneity and Functional Connectivity of Entorhinal Cortex in Vascular Mild Cognitive Impairment: A Resting-State Functional MRI Study
The aim of this study was to investigate changes in regional homogeneity (ReHo) and the functional connectivity of the entorhinal cortex (EC) in vascular mild cognitive impairment (VaMCI) and to evaluate the relationships between such changes and neuropsychological measures in VaMCI individuals. In all, 31 patients with VaMCI and 32 normal controls (NCs) underwent rs-fMRI. Differences in whole-brain ReHo and seed-based bilateral EC functional connectivity (EC-FC) were determined. Pearson's correlation was used to evaluate the relationships between regions with significant group differences and different neuropsychological measures. Vascular mild cognitive impairment (VaMCI) patients had lower scores in Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) and higher ones in Activity of Daily Living (ADL) (p < 0.05). Vascular mild cognitive impairment (VaMCI) individuals had significantly lower ReHo in the left cerebellum and right lentiform nucleus than NCs (P < 0.05, TFCE FWE correction). Vascular mild cognitive impairment (VaMCI) subjects showed significant decreases in the FC of the right EC in the right inferior frontal gyrus, right middle frontal gyrus, bilateral pre-central gyrus, and right post-central/superior parietal lobules (P < 0.05, TFCE FWE correction). Significant positive correlations were found between ReHo and MoCA scores for the right lentiform nucleus (r = 0.37, P < 0.05). The right post-central/superior parietal lobules showed a significant positive correlation between right EC-FC and MoCA scores (r = 0.37, P < 0.05). Patterns in ReHo and EC-FC changes in VaMCI patients and their correlations with neuropsychological measures may be a pathophysiological foundation of cognitive impairment, which may aid the early diagnosis of VaMCI
Surface vitrification of carbon by laser treatment: Insights of glass formation from molecular dynamics
Microstructural modification of carbon materials, such as carbon fibers (Cf) and pyrolytically deposited carbon, is important for engineering applications. However, the regulation of these materials is not an effortless task. To understand the impacts of thermal spikes from pulsed laser processing on the structural adaptation of amorphous carbon (a-C), we performed melt quenching by molecular dynamics (MD) simulations. Our results confirm that the vitrification behavior of carbon can be tuned by adjusting the cooling rate (R), which is controlled by the thermal spikes of laser processing. Moreover, we set up a two-step way to locate the critical cooling rate (Rc) of monoatomic carbon, which is refined by the sharp change in the environmental similarity parameter. Using this novel technique, we demonstrate that the ordering degree and the local atomic motif can be largely modified by going across a bar of 100 K/ps, which is extracted as the critical cooling rate to ensure the complete amorphization of carbon. This approach provides a criterion for both experimentally processing and theoretically simulating a-C structures. Therefore, this work provides guidelines on how to tune the amorphous carbon structures of engineering materials and provides an outlook for the wonderland of amorphous carbon materials
Bone Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote Recovery Following Spinal Cord Injury via Improvement of the Integrity of the Blood-Spinal Cord Barrier
Mesenchymal stem cell (MSC) transplantation has been shown to represent a potential treatment for traumatic spinal cord injury (SCI). However, there are several obstacles that need to be overcome before MSCs can be considered for clinical application, such as failure of MSCs to reach the spinal cord lesion core and possible tumor formation. Recent studies have suggested that MSC treatment is beneficial owing to paracrine-secreted factors. Extracellular vesicles are considered to be some of the most valuable paracrine molecules. However, the therapeutic mechanism of extracellular vesicles on spinal cord injury has not been studied clearly. Therefore, our study investigated the effect of systemic administration of extracellular vesicles on the loss of motor function after SCI and examined the potential mechanisms underlying their effects. Disruption of the blood-spinal cord barrier (BSCB) is a crucial factor that can be detrimental to motor function recovery. Pericytes are an important component of the neurovascular unit, and play a pivotal role in maintaining the structural integrity of the BSCB. Our study demonstrated that administration of bone mesenchymal stem cell-derived extracellular vesicles (BMSC-EV) reduced brain cell death, enhanced neuronal survival and regeneration, and improved motor function compared with the administration of BMSC-EV free culture media (EV-free CM). Besides, the BSCB was attenuated and pericyte coverage was significantly decreased in vivo. Furthermore, we found that exosomes reduced pericyte migration via downregulation of NF-κB p65 signaling, with a consequent decrease in the permeability of the BSCB. In summary, we identified that extracellular vesicles treatment suppressed the migration of pericytes and further improved the integrity of the BSCB via NF-κB p65 signaling in pericytes. Our data suggest that extracellular vesicles may serve as a promising treatment strategy for SCI
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