Search

The performance of O-rings is crucial to the large variety of core equipment or components that employ O-ring seals. O-ring surface imperfections that meet quality standards are allowed to be put into service. However, the presence of surface imperfections will inevitably affect the performance of the O-ring seal. To this end, in this study, nonlinear finite element models of O-ring structures with an ideal circular cross section and three surface imperfections of parting line projection, backrind, and excessive trimming in accordance with ISO standards are developed. On this basis, their contact conditions and stress distributions are calculated, analyzed, discussed, and compared. The results show that the maximum contact pressure in the area where the imperfection is located increases and that the presence of the imperfection does not reduce the sealing performance. Backrind under low pressure conditions and excessive trimming do not affect the maximum Von-Mises stress. While backrind under high pressure conditions and parting line projection can make the maximum Von-Mises stress increase significantly. In particular, at a fluid pressure of 10 MPa, backrind causes a 21% increase in the maximum Von-Mises stress, while parting line projection causes a 198% increase. Such a large increase in stress will increase the likelihood of fatigue failure and breakage. [ABSTRACT FROM AUTHOR]

Background: Synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome is a rare autoimmune disease characterized by skin or osteoarticular damage. SAPHO syndrome is often misdiagnosed or missed diagnosis due to lack of overall understanding of the disease by clinicians. Purpose: To analyze the clinical symptoms and imaging features of six Han patients with SAPHO syndrome in order to provide reference for doctors to diagnose SAPHO syndrome. Material and Methods: This study retrospectively analyzed the clinical data of six Han patients with SAPHO syndrome. Results: All six Han patients with SAPHO syndrome had severe acne or pustulosis of the hands and feet, and all of them had osteoarticular damage, including five cases involving the sternoclavicular joint. Some patients showed a specific and typical "bull's head" sign on 99mTc-labeled methylene diphosphonate bone imaging. Among the six patients recruited, there was one thoracic vertebra, one cervical vertebra, one sacroiliac joint, and one peripheral joint involvement. Two patients had limited activity due to severe osteoarticular damage. Conclusion: Due to the atypical clinical symptoms of SAPHO syndrome, most patients will experience a tortuous and long diagnostic process, while a correct understanding and timely intervention of SAPHO syndrome are essential to improve the prognosis of patients. [ABSTRACT FROM AUTHOR]

Laminar flow in circular pipes is widespread in various fields. Poiseuille's law is the classical equation describing the pressure–flow rate relationship for laminar flow in circular pipes. However, the fluid viscosity is treated as a constant in Poiseuille's law. Therefore, Poiseuille's law cannot be used to accurately analyze fluids that have viscosities that vary exponentially with pressure, such as hydraulic oils and lubricating oils. In this study, with the exponential viscosity-pressure characteristics, a total of four simple and explicit equations are given for calculating the flow rate or pressure difference of the pipe, and corresponding polynomial expansions are derived based on the Taylor series. Experimental tests and computational fluid dynamics simulations are carried out to verify the correctness of the theoretical equations, with error of less than 6% and 2%, respectively. An error analysis of the theoretical equations for different numbers of polynomial terms is also performed. The results show that the proposed theoretical equations all degenerate to the classical Poiseuille's law when the number of polynomial terms is taken to be 1, and the relative errors are less than ±5% for viscosity changes less than 10%. When the number of terms is 2, the relative error is less than ±5% for viscosity changes less than 40%. In the calculation of connection pipelines of a deep-sea hydraulic actuator, the difference in pressure loss calculated with or without viscosity change is 31.47% and reaches up to 5.7202 MPa, which shows the practical value of this research in piping systems. [ABSTRACT FROM AUTHOR]

The pressure compensator is an important equipment of the deep-sea hydraulic system to provide the functions of pressure and volume compensation. In this paper, the structure features and static force analysis of the pressure compensator are studied. The physical model of the pressure compensator is established, and its dynamic characteristics influenced by the ambient pressure, the compensated flow and the temperature change are all analyzed. The entire working process of the pressure compensator is then researched. Therefore, two design criteria for reliability and dynamic characteristics respectively are proposed. A pressure compensator for 6000 m deep in the sea was designed and manufactured. Simulations and high-pressure experiments of the designed pressure compensator were conducted. The results show that the dynamic response of the compensated pressure under each input is all composed of a ramp change, a step change and a damped oscillation. The effective area of the rolling diaphragm, the spring stiffness and the mass of the diaphragm-piston assembly are the key design parameters to ensure the reliability and good dynamic characteristics of the pressure compensator. Simulation and high-pressure experiments verified the volume and pressure compensation function of the pressure compensator in the deep-sea environment. [ABSTRACT FROM AUTHOR]

A study was conducted to characterize a spatiotemporal neural network for partially occluded object recognition. The neural network supported tap delays to recognize both single objects and partially occluded objects. The dominant points of objects were obtained using curvature guided polygonal approximation and a split-and-merge algorithm. Results indicated that the spatiotemporal neural network can effectively recognize partially occluded objects by sequential correlation.

Objective: We conducted an in-depth study of the immune system and ferroptosis to identify prognostic biomarkers and therapeutic targets for renal clear cell carcinoma., Methods: Immune ferroptosis-related differentially expressed genes (IFR-DEGs) were selected from The Cancer Genome Atlas (TCGA). A lasso-Cox risk scoring model was established; its prognostic value was determined using prognostic analysis and single multivariate Cox analysis. Model genes were subjected to subcellular fluorescence localization, mRNA and protein expression analyses, and single-cell RNA sequencing localization analysis. Risk score was analyzed using the immune score, immune infiltrating cell correlation, immune checkpoint, TIDE, and drug sensitivity., Results: A total of 103 IFR-DEGs were identified; a risk model comprising ACADSB, CHAC1, LURAP1L, and PLA2G6 was established. The survival curve, single multivariate Cox regression, and receiver operating characteristic (ROC) curve analysis showed that the model had good predictive ability (p < 0.05). It was also validated using the validation set and total cohort. Subcellular fluorescence localization revealed that ACADSB, CHAC1, and PLA2G6 were distributed in the cytoplasm and LURAP1L in the nucleus. The mRNA and protein expression trends were consistent. Single-cell RNA sequencing mapping revealed that ACADSB was enriched in distal tubule cell clusters. In the Kidney renal clear cell carcinoma (KIRC) mutation correlation analysis, 1.56% of the patients were found to have genetic alterations; The Spearman correlation analysis of model gene mutations showed that ACADSB was positively correlated with LURAP1L , which may have a synergistic effect; it was negatively correlated with CHAC1 and PLA2G6 , and CHAC1 was negatively correlated with LURAP1L , which may have an antagonistic effect. Model and immune correlation analyses found that high-risk patients had significantly higher levels of CD8+ T cells, regulatory T cells (Tregs), immune checkpoints, immune scores, and immune escape than those in low-risk patients. High-risk patients had a higher susceptibility to small-molecule drugs., Conclusion: A novel prognostic model of immune ferroptosis-related genes ( ACADSB, CHAC1, LURAP1L, and PLA2G6 ), which plays an important role in immune infiltration, microenvironment, and immune escape, was constructed. It effectively predicts the survival of patients with KIRC., Competing Interests: None., (AJTR Copyright © 2022.)

The gut microbiota can affect human metabolism, immunity, and other biologic pathways through the complex gut-kidney axis (GKA), and in turn participate in the occurrence and development of kidney disease. In this study, 39 patients with stage 4-5 chronic kidney disease (CKD) and 40 healthy individuals were recruited and 16S rDNA sequencing was performed to analyze the V3-V4 conserved regions of their microbiota. A total of 795 operational taxonomic units (OTUs) shared between groups or specific to each group were obtained, among which 255 OTUs with significant differences between the two groups were identified ( P <0.05). Adonis differential analysis showed that the diversity of gut microbiota was highly correlated with CKD stages 4-5. Additionally, 61 genera with differences in the two groups were identified ( P <0.05) and 111 species with significant differences in the phyla, classes, orders, families, and genera between the two groups were identified ( P <0.05). The differential bacterial genera with the greatest contribution were, in descending order: c&#95;Bacteroidia, o&#95;Bacteroidales, p&#95;Bacteroidetes, c&#95;Clostridia, o&#95;Clostridiales, etc. Those with the greatest contribution in stages 4-5 CKD were, in descending order: p&#95;Proteobacteria, f&#95;Enterobacteriaceae, o&#95;Enterobacteriales, c&#95;Gammaproteobacteria, c&#95;Bacilli, etc. The results suggest that the diversity of the microbiota may affect the occurrence, development, and outcome of the terminal stages of CKD., Competing Interests: None., (AJTR Copyright © 2021.)