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Abstract Sarcopenia has been considered an adverse prognostic factor in cancer patients. Intramuscular adipose tissue content, as a new marker of sarcopenia, can effectively reflect skeletal muscle quality. The aim of this study was performed to evaluate the association between high intramuscular adipose tissue content (IMAC) and survival outcomes and postoperative complications in cancer patients. Specific databases, including the Web of Science, Embase and Web of Science, were systematically searched to identify relevant articles evaluating the prognostic value of IMAC in cancer patients. Hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were utilized for comprehensive analysis. All data analyses were performed using STATA 12.0 software. A total of 25 studies from 24 articles including 5663 patients were enrolled in the study. Meta‐analysis showed that high IMAC was associated with unfavourable overall survival (OS) (HR: 2.21, 95% CI: 1.70–2.86, P

Parabolic dish concentrators have demonstrated the highest thermal and optical efficiencies among the available concentrator options. This paper proposes a novel design approach for fabricating large parabolic dish concentrators by employing compliant petals optimized through Particle Swarm Optimization-Genetic Algorithm (PSO-GA). The design concept involves using cables to pull the outer corners of the petals towards the center, resulting in the creation of finely formed dish mirrors. These mirrors are constructed from thin, optimal-shaped metal petals with highly reflective surfaces. In addition, an analytical model is presented to optimize the bending stiffness of the petals by strategically arranging punched holes using PSO-GA. The proposed design concept is validated through the application of Finite Element Analysis and ray tracing software, specifically LightTools, as well as laboratory experiments. Based on the demonstration with a 1m-diameter parabolic dish, it was observed that a receiver surface with a radius of 3.5 cm could achieve an impressive sunlight collection efficiency of up to 98%. This innovative design approach offers several advantages, including simplified fabrication and transportation of flat mirror elements to field sites, which can potentially lead to cost reductions and highly efficient solar energy solutions.

BackgroundTumor burden score (TBS) based on maximum tumor diameter and number has been shown to correlate with prognosis in patients with hepatocellular carcinoma (HCC). Nevertheless, the results are conflicting. Hence, we conducted a meta-analysis to analyze the association between TBS and survival outcomes of HCC patients.MethodsA comprehensively search of the databases including PubMed, Embase and Web of Science was performed to retrieve studies satisfying the inclusion criteria until August 31, 2023. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. All the data analyses were carried out by STATA 12.0.Results10 retrospective studies containing 25073 patients were incorporated in the study. The results demonstrated that high TBS was markedly association with poor overall survival (OS) (HR: 1.79, 95% CI: 1.45-2.23) and relapse-free survival / progression-free survival(RFS/PFS) (HR: 1.71; 95% CI: 1.42-2.07). Subgroup analysis showed that the prognostic value of TBS in HCC was not affected by any subgroup.ConclusionsTBS may be an efficient prognostic index in HCC patients.

Spaceborne deployable cylindrical antennas have broad application prospects in the fields of space earth observation and remote-sensing detection because of their significant advantages of ultralong aperture, high gain, and flexible beam scanning. As application requirements rapidly develop, a new type of spaceborne deployable cylindrical antenna mechanism with a large diameter and deployability is urgently needed. This paper presents an innovative design for a cylindrical deployable antenna mechanism based on 18R triangular prism elements based on graph theory. The correctness of the configuration is verified by developing a prototype. First, four kinds of nonoverconstrained 12-bar triangular prism-stabilized truss structure configurations and their corresponding topological diagrams are constructed. Second, based on graph theory, three types of 102 triangular prism-stabilized truss mechanism configurations that can be folded into linear mechanisms are derived. Third, the kinematic pair configuration is established to achieve a single-degree-of-freedom 7R2U9S triangular prism deployable unit. Fourth, combined with the geometric topology characteristics of the unit network, a triangular prism unit networking method is proposed, and a cylindrical network mechanism configuration based on 18R triangular prism units is obtained. A prototype was fabricated by 3D printing, and an expansion and retraction function test was conducted, which verified the correctness of the theoretical analysis in this paper. Finally, a new concept configuration for a parabolic cylindrical antenna is proposed. This paper provides a reference for the configuration of large-scale folding truss structures with unit expansion.

Abstract Background Breast cancer (BC) negatively impacts the health of women worldwide. Circular RNAs (circRNAs) are a group of endogenous RNAs considered essential regulatory factor in BC tumorigenesis and progression. However, the underlying molecular mechanisms of circRNAs remain unclear. Methods Expression levels of circPAPD4, miR-1269a, CREBZF, and ADAR1 in BC cell lines and tissues were measured using bioinformatics analysis, RT-qPCR, ISH, and IHC. Cell proliferation and apoptosis were measured using CCK8, EdU staining, flow cytometry, and TUNEL assays. Pearson correlation analysis, RNA pull-down, dual-luciferase reporter, and co-immunoprecipitation assays were used to explore the correlation among circPAPD4, miR-1269a, CREBZF, STAT3, and ADAR1. Effects of circPAPD4 overexpression on tumor progression were investigated using in vivo assays. Moreover, CREBZF mRNA delivered by polymeric nanoparticles (CREBZF-mRNA-NPs) was used to examine application value of our findings. Results CircPAPD4 expression was low in BC tissues and cells. Functionally, circPAPD4 inhibited proliferation and promoted apoptosis in vitro and in vivo. Mechanistically, circPAPD4 biogenesis was regulated by ADAR1. And circPAPD4 promoted CREBZF expression by competitively binding to miR-1269a. More importantly, CREBZF promoted circPAPD4 expression by suppressing STAT3 dimerization and ADAR1 expression, revealing a novel positive feedback loop that curbed BC progression. Systematic delivery of CREBZF-mRNA-NPs effectively induced CREBZF expression and activated the positive feedback loop of circPAPD4/miR-1269a/CREBZF/STAT3/ADAR1, which might suppress BC progression in vitro and in vivo. Conclusion Our findings firstly illustrated that circPAPD4/miR-1269a/CREBZF/STAT3/ADAR1 positive feedback loop mediated BC progression, and delivering CREBZF mRNA nanoparticles suppressed BC progression in vitro and in vivo, which might provide novel insights into therapeutic strategies for breast cancer.

Abstract Solar arrays are the primary energy source for spacecraft. Although traditional rigid solar arrays improve power supply, the quality increases proportionally. Hence, it is difficult to satisfy the requirements of high-power and low-cost space applications. In this study, a shape-memory polymer composite (SMPC) boom was designed, fabricated, and characterized for flexible reel-type solar arrays. The SMPC boom was fabricated from a smart material, a shape-memory polymer composite, whose mechanical properties were tested. Additionally, a mathematical model of the bending stiffness of the SMPC boom was developed, and the bending and buckling behaviors of the boom were further analyzed using the ABAQUS software. An SMPC boom was fabricated to demonstrate its shape memory characteristics, and the driving force of the booms with varying geometric parameters was investigated. We also designed and manufactured a reel-type solar array based on an SMPC boom and verified its self-deployment capability. The results indicated that the SMPC boom can be used as a deployable unit to roll out flexible solar arrays.

Aiming at the problems of aerodynamic resistance, noise, and operation safety of rubber windshields, a new mechanical external windshield for the train was designed. Based on the model of three car high-speed train, the frequency spectrum characteristics of aerodynamic noise were analyzed under 300 km/h, 400 km/h, and 500 km/h working conditions, and the aerodynamic characteristics and flow field distribution of mechanical external windshield were compared with those of the existing windshields. The results show that under the same speed, the pressure distribution of the mechanical external windshield was relatively gentle, and the velocity loss of the vortex generated in the cavity was small. The radiated noise from the dipole sound source on the train surface decreased with the increase of the distance from the vehicle body. Also, as the frequency increased, the noise sound pressure presented a downward trend, and the distribution tended to be uniform gradually. In directivity, the sound pressure on both sides of the windshield has a certain symmetry. The sound pressure fluctuation was consistent with the frequency change, and the maximum sound pressure occurred at the position where the curvature change at the upper end of the windshield was the largest. The research results in this paper can provide some reference for the design of the train windshield structure and the reduction of train resistance and noise.

Background: Identifying patients with hepatocellular carcinoma (HCC) at high risk of recurrence after hepatectomy can help to implement timely interventional treatment. This study aimed to develop a machine learning (ML) model to predict the recurrence risk of HCC patients after hepatectomy. Methods: We retrospectively collected 315 HCC patients who underwent radical hepatectomy at the Third Affiliated Hospital of Sun Yat-sen University from April 2013 to October 2017, and randomly divided them into the training and validation sets at a ratio of 7:3. According to the postoperative recurrence of HCC patients, the patients were divided into recurrence group and non-recurrence group, and univariate and multivariate logistic regression were performed for the two groups. We applied six machine learning algorithms to construct the prediction models and performed internal validation by 10-fold cross-validation. Shapley additive explanations (SHAP) method was applied to interpret the machine learning model. We also built a web calculator based on the best machine learning model to personalize the assessment of the recurrence risk of HCC patients after hepatectomy. Results: A total of 13 variables were included in the machine learning models. The multilayer perceptron (MLP) machine learning model was proved to achieve optimal predictive value in test set (AUC = 0.680). The SHAP method displayed that γ-glutamyl transpeptidase (GGT), fibrinogen, neutrophil, aspartate aminotransferase (AST) and total bilirubin (TB) were the top 5 important factors for recurrence risk of HCC patients after hepatectomy. In addition, we further demonstrated the reliability of the model by analyzing two patients. Finally, we successfully constructed an online web prediction calculator based on the MLP machine learning model. Conclusion: MLP was an optimal machine learning model for predicting the recurrence risk of HCC patients after hepatectomy. This predictive model can help identify HCC patients at high recurrence risk after hepatectomy to provide early and personalized treatment.

Abstract Background Systemic inflammation is crucial for the development and progression of cancers. The advanced lung cancer inflammation index (ALI) is considered to be a better indicator of systemic inflammation than current biomarkers. However, the prognostic value of the ALI in gastrointestinal neoplasms remains unclear. We performed the first meta-analysis to explore the association between ALI and gastrointestinal oncologic outcomes to help physicians better evaluate the prognosis of those patients. Methods Eligible articles were retrieved using PubMed, the Cochrane Library, EMBASE, and Google Scholar by December 29, 2022. Clinical outcomes were overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and cancer-specific survival (CSS). Results A total of 18 articles with 6898 patients were included in this meta-analysis. The pooled results demonstrated that a low ALI was correlated with poor OS (HR = 1.914, 95% CI: 1.514–2.419, P

A novel three-layer integrated structure was designed to meet the thermal-insulation and load-bearing requirements of high-speed telescopic wing aircraft. The structure consists of heat shield layer, load-bearing skeleton, and pyramid lattice structure filled with aerogel to achieve the insulation function. Sensitivity analysis of the design parameters and optimal design of the integrated structure was carried out, and the structure was optimized by using response surface method. Compared to the initial structure, the optimized structure has an equivalent thermal conductivity of 0.0276, reduced by 40%, and a relative density of 685 . 5 kg / m 3 , reduced by 3.7%. And it has a thermal conductivity that is over 20% lower than that of ceramic insulating tiles. Then, the integrated structure was regarded as a homogeneous plate, and the equivalent mechanical and thermal parameters were determined and verified by simulation and experimental results. The equivalence error was controlled within 10%. Finally, a simulation model of the telescopic wing was established. The result shows that the maximum deformation under 20 kPa surface pressure is 3.96 mm. The temperature resistance of the structure surface is up to 1500°C, and the wing internal temperature is controlled within 200°C after 1200 s of thermal loading. The results verified that the integrated structure meets the requirement of a high-speed telescopic wing.

ObjectiveThere is some evidence for an association between gut microbiota and nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), and viral hepatitis, but no studies have explored their causal relationship.MethodsInstrumental variables of the gut microbiota (N = 13266) and gut microbiota-derived metabolites (N = 7824) were acquired, and a Mendelian randomization study was performed to explore their influence on NAFLD (1483 European cases and 17,781 European controls), ALD (2513 European cases and 332,951 European controls), and viral hepatitis risk (1971 European cases and 340,528 European controls). The main method for examining causality is inverse variance weighting (IVW).ResultsIVW results confirmed that Anaerotruncus (p = 0.0249), Intestinimonas (p = 0.0237), Lachnoclostridium (p = 0.0245), Lachnospiraceae NC2004 group (p = 0.0083), Olsenella (p = 0.0163), and Peptococcus (p = 0.0472) were protective factors for NAFLD, and Ruminococcus 1 (p = 0.0120) was detrimental for NAFLD. The higher abundance of three genera, Lachnospira (p = 0.0388), Desulfovibrio (p = 0.0252), and Ruminococcus torques group (p = 0.0364), was correlated with a lower risk of ALD, while Ruminococcaceae UCG 002 level was associated with a higher risk of ALD (p = 0.0371). The Alistipes (p = 0.0069) and Ruminococcaceae NK4A214 group (p = 0.0195) were related to a higher risk of viral hepatitis. Besides, alanine (p = 0.0076) and phenyllactate (p = 0.0100) were found to be negatively correlated with NAFLD, while stachydrine (Op = 0.0244) was found to be positively associated with NAFLD. The phenylacetate (p = 0.0353) and ursodeoxycholate (p = 0.0144) had a protective effect on ALD, while the threonate (p = 0.0370) exerted a detrimental influence on ALD. The IVW estimates of alanine (p = 0.0408) and cholate (p = 0.0293) showed their suggestive harmful effects against viral hepatitis, while threonate (p = 0.0401) displayed its suggestive protective effect against viral hepatitis.ConclusionIn conclusion, our research supported causal links between the gut microbiome and its metabolites and NAFLD, ALD, and viral hepatitis.

BackgroundMany reports have described that abnormal nectin-4 expression may be used as a prognostic marker in many tumors. However, these studies failed to reach a consensus. Here, we performed a meta-analysis to comprehensively evaluate the prognostic value of nectin-4 in cancers.MethodsRelevant studies were identified through a comprehensive search of PubMed, EMBASE and Web of science until August 31, 2022. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to evaluate the relationship between nectin-4 expression and overall survival (OS) and disease-free survival/progression-free survival/relapse-free survival (DFS/PFS/RFS). Odds ratios (ORs) with 95% CIs were applied to assess the relationship between nectin-4 expression and clinicopathologic features. Subgroup analysis was performed to explore the sources of heterogeneity. Sensitivity analysis and funnel plot were used to test the reliability of the results. All data analyses were performed using STATA version 12.0 software.ResultsFifteen articles involving 2245 patients were included in the meta-analysis. The pooled analysis showed that high nectin-4 expression was significantly associated with poor OS (HR: 1.75, 95% CI: 1.35–2.28). There was no relationship between high nectin-4 expression and DFS/PFS/RFS (HR: 178, 95% CI: 0.78–4.08).Subgroup analyses revealed that that high nectin-4 expression mainly presented adverse OS in esophageal cancer (EC) (HR: 1.78, 95% CI: 1.30–2.44) and gastric cancer (GC) (HR: 1.92, 95% CI: 1.43–2.58). We also found that high nectin-4 expression was associated with tumor diameter (big vs small) (OR: 1.96, 95% CI: 1.02–3.75), tumor stage (III-IV vs I-II) (OR: 2.04, 95% CI: 1.01–4.12) and invasion depth (T3+T4 vs T2+T1) (OR: 3.95, 95% CI: 2.06–7.57).ConclusionsNectin-4 can be used as an effective prognostic indicator for specific cancers.

The variable-sweep wing is very attractive for cross-speed domain aircraft. The shear-sliding rigid-flexible coupled skin variable-sweep wing and its associated mechanism are designed and optimized. The variable-sweep wing has smooth continuous deformation and rigid-flexible coupling features. The calculation model of the sliding skin patch segmentation strategy is established, and the aerodynamic characteristics of the two-dimensional airfoil before and after the deformation of the wing skin are analyzed. According to the deformation characteristics of sliding skin, the configuration of the associated mechanism is determined, and the kinematic characteristics of the reference points of each skin are calculated. The kinematic simulation verifies the force of the mechanism model at the joint of skin surfaces during the deformation process. Considering the aerodynamic heat at supersonic speed, the heat transfer, heat distribution, and structural thermal modes between the flow field and the skin are calculated based on the finite element method. The dynamic characteristics of the swept wing with different flight speeds and different morphologies are analyzed. The natural frequencies are found to be reduced by about 30% to 50% compared to cold models at supersonic speeds. Based on the results of the thermal fluid-solid coupling calculation, the skeleton structure of the swept wing is optimized, and the skeleton structure with 25% mass reduction and better performance is obtained.

BackgroundNumerous studies showed that preoperative platelet-albumin-bilirubin (PALBI) grade was closely related to the prognostic outcome of patients with hepatocellular carcinoma (HCC). However, the conclusions were inconsistent. Therefore, we implemented the study to comprehensively evaluate the association between PALBI grade and prognosis in patients with HCC.MethodsRelevant articles were collected from the specified databases until February 10, 2022. We included all studies exploring the relationship between PALBI grade and prognosis in HCC patients. We used the hazard ratio (HR) and 95% confidence interval (CI) to calculate the comprehensive analysis. All data analyses were performed using STATA 12.0.ResultsThirteen retrospective articles containing 15534 patients were included in the meta-analysis. The pooled results displayed that the high PALBI grade was obviously correlated with poor overall survival (OS) (HR: 1.71, 95% CI: 1.46-2.02) and disease-free survival/relapse-free survival (DFS/RFS) (HR:1.31; 95% CI: 1.11–1.54). Subgroup analyses further confirmed the reliability of the comprehensive results.ConclusionsPALBI may be a valid prognostic indicator in HCC patients. More investigations were needed to test our findings.

In the spin-off acceleration stage during high-speed rotation in space, the deployable arm of the space gravity simulation device must withstand a large axial centrifugal force and a driving torque. In this paper, a large-scale high-speed rotating deployable arm is proposed, and the relevant characteristics during the rotation process are analyzed. A new driving mode of towed deployment is proposed that can lead to the rapid and efficient deployment of a large-scale deployable arm. First, an optimized configuration of a deployable arm is proposed. Second, the deployment driving process of the deployable arm under several different drag driving modes is simulated and analyzed, and a comparative analysis is performed to select a simple and reliable drag deployment driving scheme. Then, the effects of various disturbances on the posture of the deployable arm during the rotation process are explored, guiding the posture control of the deployable arm. Finally, a 10 m four-unit prototype is developed for the stiffness and rotation tests, which verify that the theoretical analysis in this paper is correct.

Background: Although many genes related to epithelial-mesenchymal transition (EMT) have been explored in hepatocellular carcinoma (HCC), their prognostic significance still needs further analysis.Methods: Differentially expressed EMT-related genes were obtained through the integrated analysis of 4 Gene expression omnibus (GEO) datasets. The univariate Cox regression and Lasso Cox regression models are utilized to determine the EMT-related gene signature. Based on the results of multivariate Cox regression, a predictive nomogram is established. Time-dependent ROC curve and calibration curve are used to show the distinguishing ability and consistency of the nomogram. Finally, we explored the correlation between EMT risk score and immune immunity.Results: We identified a nine EMT-related gene signature to predict the survival outcome of HCC patients. Based on the EMT risk score’s median, HCC patients in each dataset were divided into high and low-risk groups. The survival outcomes of HCC patients in the high-risk group were significantly worse than those in the low-risk group. The prediction nomogram based on the EMT risk score has better distinguishing ability and consistency. High EMT risk score was related to immune infiltration.Conclusion: The nomogram based on the EMT risk score can reliably predict the survival outcome of HCC patients, thereby providing benefits for medical decisions.

Motion strategy analysis at the pre-bending stage is a fundamental component of underactuated finger grasp research. This study presents the pre-bending motion strategy and corresponding analysis of cable driving forces a 3-DOF underactuated finger comprising cable truss units. The structure and four motion strategies at the pre-bending stage are illustrated. The equivalent joint-driven and quasi-static motion models are established in the case where one or two cable driving forces drive the finger. Quasi-static motion model is established, and four typical quasi-static coupled motion space and distributions of corresponding cable driving forces are analysed. In accordance with the kinetic energy theorem and Lagrange’s dynamical method, a sampled and general dynamic model is established. Through matrix transformation, a hypothetical “PPA” type dynamic model is obtained. On the basis of the “PPA” dynamic model, three grasping control strategies at pre-bending stage are carried out. Valid simulations and experiments are conducted to verify the accuracy of the coupled bend inwards motion and control strategy.

Thin-walled structures are widely used in anti-collision devices for various vehicles due to their light weight and high energy absorption. Offset collision is a common scene in various traffic accidents. Because the commonly used thin-walled structures do not consider this complex collision method, the energy absorption effect of the structure cannot meet the requirements. In this paper, a C-shaped frame structure composed of thin-walled steel tubes is proposed. The configuration of the structure is studied through theoretical analysis and numerical simulation, and it is found that the structure can absorb energy stably in the offset collision. The offset experiment and simulation were carried out, and the crashworthiness of the structure was investigated to verify the accuracy and feasibility of the numerical analysis method. A large-scale parameter simulation analysis was carried out, and the influence characteristics of the structure configuration, different materials and different sections were investigated. Based on the above test and numerical analysis results, an optimal design method for improving the crashworthiness of structures considering offset collisions is proposed. This paper can provide theoretical and technical support for the related research on the integrated anti-climbing energy-absorbing parts of rail trains under offset collision.

To meet the requirements of deployable structures in aerospace engineering with light weight and high stiffness, this paper proposes the triangular space membrane deployable mechanism based on deployable booms, then conducts dynamic analysis and multiobjective optimization. The configuration design and mass calculation for the membrane mechanism are carried out, including its unfolding support mechanism and tensioned membrane scheme. With a view to performing the dynamic characteristics analysis and parametric studies, the finite element simulation model of the membrane mechanism, including boom, cable and membrane, is built and validated against test results obtained by Polytec. On the basis of the simulation results, a surrogate model of fundamental frequency is established by adopting the response surface method and applied to multiobjective optimization combined with the mass formula. Then, the optimal dynamic and lightweight design parameters are solved via the genetic algorithm. The results provide an indication to aid with the design and analysis of space membrane deployable mechanisms according to the required properties and space mission requirements.

Collisions between rail transit vehicles are unavoidable. In order to alleviate the disaster caused by the collision, energy-absorbing and shock-absorbing materials are generally installed at the front end of the rail vehicle. In this paper, a variable buffer-force planing energy-absorbing device for rail transit vehicles was prepared. The buffer force was changed by length (Dx), angle (A) and thickness (W). First, we manufactured one type of material, and data were obtained through experimentation. Second, we used Ls-DYNA to simulate this material, and determined the accuracy between the simulation and the test. Third, various parameters of the material were simulated by Ls-DYNA. The results show that changing Dx greatly affects the performance of the material, W has no obvious effect on the performance, and A is important for the materials properties. Based on finite element simulation, the functional model relationship between the average force and various parameters was deduced. This lays the groundwork for the application of the variable buffer-force planing energy absorbing device.

BackgroundThe prognostic significance of tumor burden score (TBS) on patients who underwent curative-intent resection of intrahepatic cholangiocarcinoma (ICC) has not been evaluated. The present study aimed to investigate the impact of TBS and its synergistic effect with CA19-9 (combination of TBS and CA19-9, CTC grade) on long-term outcomes.MethodsPatients who underwent radical resection of ICC between 2009 and 2017 were retrospectively identified from a multi-center database. The overall survival (OS) and recurrence-free survival (RFS) were examined in relation to TBS, serum preoperative CA19-9, and CTC grade.ResultsA total of 650 patients were included in our study (509 in the derivation cohort and 141 in the validation cohort). Kaplan–Meier curves showed that both TBS and CA19-9 levels were strong predictors of survival outcomes. Patients with elevated TBS grade or elevated CA19-9 were associated with worse OS and RFS (both p < 0.001). As expected, CTC grade also performed well in predicting long-term outcomes. Patients with low TBS/low CA19-9 (CTC grade 1) were associated with the best OS as well as RFS, while high TBS/high CA19-9 (CTC grade 3) correlated to the worst outcomes. In the validation cohort, TBS grade, preoperative CA19-9, and CTC grade also stratified prognosis among patients (p < 0.001 for each).ConclusionsBoth tumor morphology (tumor burden) and tumor-specific biomarker (serum CA19-9) were important when evaluating prognosis of patients with resectable ICC. Serum CA19-9 and TBS showed a synergistic effect on prognostic evaluation. CTC grade was a promising tool in stratifying prognosis of ICC patients after curative resection.

PurposeTo unravel the oncogenic role of CDCA4 in different cancers from the perspective of tumor immunity.MethodsRaw data on CDCA4 expression in tumor samples and paracancerous samples were obtained from TCGA and GTEX databases. In addition, we investigated pathological stages and the survival analysis of CDCA4 in pan-cancer across Gene Expression Profiling Interactive Analysis (GEPIA) database. Cox Proportional Hazards Model shows that high CDCA4 levels are associated with several vital indicators in oncology. On the one hand, we explored the correlation between CADA4 expression and tumor immune infiltration by the TIMER tool; On the other hand, we utilized the methods of CIBERSORT and ESTIMATE computational to evaluate the proportion of tumor infiltrating immune cells (TIIC) and the amounts of stromal and immune components based on TCGA database. The use of antineoplastic drugs and the expression of CDCA4 also showed a high correlation via linear regression. Protein–Protein Interaction analysis was performed in the GeneMANIA database, and enrichment analysis was performed and predicted signaling pathways were identified by using Gene Ontology and Kyoto Encyclopedia of Genes. The correlation between CDCA4 expression with Copy number variations (CNV) and methylation is detailed, respectively. Molecular biology experiments including Western blotting, flow cytometry, EDU staining, Transwell and Wound Healing assay to validate the cancer promoting role of CDCA4 in hepatocellular carcinoma (HCC).ResultsMost tumors highly expressed CDCA4. Elevated CDCA4 expression was associated with poor OS and DFS. There was a significant correlation between CDCA4 expression and TITCs. Moreover, markers of TIICs exhibited distinct patterns of CDCA4 associated immune infiltration. In addition, we pay attention to the association between the expression of CDCA4 and the use of the anti-tumor drugs. CDCA4 is related to biological progress (BP), cellular component (CC) and molecular function (MF). Dopaminergic Synapse, AMPK, Sphingolipid, Chagas Disease, mRNA Surveillance were significantly enriched pathways in positive and negative correlation genes with CDCA4. CNV is thought to be a positive correlation with CDCA4 expression. Conversely, methylation is negative correlation with CDCA4 expression. Molecular biology experiments confirm a cancer promoting role for CDCA4 in HCCConclusionCDCA4 may serve as a biomarker for cancer immunologic infiltration and poor prognosis, providing a new way of thinking for cancer treatment.

A high-precision networking method for a modular deployable antenna with ultramultiple modules is proposed to solve the problem of achieving an accurate formation of the structure of a large-aperture modular deployable space antenna. In accordance with the general requirements for the deployment surface of deployable antennas, the structure composition and deployment principle of a deployable antenna are analyzed, and the topological law of a hexagonal prism modular structure is expounded. On the basis of basic theories of differential geometry, analytical geometry, and robotics, the mathematical model of an envelope circle and that of its center are established. Then, a networking model of structure that includes 61 modules in the fully deployed state is established. Finally, the established model is verified via a numerical simulation method, and the influence law of structural parameters on networking characteristics is analyzed and studied. Simulation results show that the networking method can realize an accurate connection of multiple modules. The networking method for the structure of a modular deployable antenna proposed in this study can provide a reference for research on basic theory of a deployable antenna’s mechanism and related engineering applications.

The hinge, a key component of deployable space mechanism, has a significant influence on the precision of the whole mechanism. Hysteresis is one of the uncontrollable factors affecting the precision of the hinge. However, much work so far has focused on the equivalent model of hysteresis, which is far from the actual situation. In this paper, the hysteresis model of the general rotary hinge was established via the finite element method (ABAQUS/Standard 6.14-4). The correctness of the model was verified by experiments, and the loss factor was defined to measure the size of hysteresis. The response surface method was then used to establish the response surface of the hysteresis loss factor of the general rotary hinge. Results show that the hinge was optimised. By comparing the response surfaces of the two types of hinges, the modified hinge can effectively reduce hysteresis loss factor. Importantly, the repeatability of the hinge can be effectively improved by reducing hysteresis loss factor through repeatability experiments. Using this method, the response surface of the hinge's hysteresis loss factor can be established accurately, and the hysteresis loss factor can be reduced through optimal design to improve the precision of the hinge. This method can provide reference and guidance for the hinge design of the high-precision deployable mechanism.

This article proposes a novel soft pneumatic actuator inspired by the segmented structure of earthworms. The actuator adopts a new structure of free bottom to eliminate the constraint of the bottom and enlarge the bending capacity of the actuator. Through simulation, it is found that the new actuator improves the bending angle by 20% and output force by 40% compared with traditional actuator. Moreover, key parameters of the actuator are analyzed to acquire their effect on bending angle and bending linearity. A guideline for the design and optimization of the actuator is proposed. To validate the simulation results, we build up a test platform to test bending angle and output force of the actuators, the results shows that errors between the simulation and the test remained in the limit of about 10%. Finally, a three-jaw soft gripper is fabricated and its grasping strategy is studied. The quantitative analysis shows its excellent adaptability and load capacity.

Background: The potential role of Neurotrophic factor-3(NTF3) in liver cancer is unknown. Therefore, we aimed to explore the clinical value of NTF3 in hepatocellular carcinoma (HCC).Methods: We used a variety of databases to analyze the expression, relationship with prognosis and immune significance of NTF3 in liver cancer through bioinformatics.Results: NTF3 was low expressed in HCC and was an independent prognostic factor in patients with HCC. CIBERSORT analysis indicated that NTF3 expression was positively correlated with CD4+ cells, mast cells, NK cells, macrophages and B cells in the tumor microenvironment. Furthermore, we found that NTF3 expression was negatively correlated with the immune checkpoints PD-L1, TIGIT and TIM-3. Functional network analysis revealed that NTF3 regulates HCC progression through a variety of cancer-related kinases, transcription factors and signaling pathways.Conclusions: We demonstrate that NTF3 correlates with prognosis and immune infiltration in HCC.

Background: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, and its prognosis remains unsatisfactory. The identification of new and effective markers is helpful for better predicting the prognosis of patients with HCC and for conducting individualized management. The oncogene Aurora kinase A (AURKA) is involved in a variety of tumors; however, its role in liver cancer is poorly understood. The aim of this study was to establish AURKA-related gene signatures for predicting the prognosis of patients with HCC.Methods: We first analyzed the expression of AURKA in liver cancer and its prognostic significance in different data sets. Subsequently, we selected genes with prognostic value related to AURKA and constructed a gene signature based on them. The predictive ability of the gene signature was tested using the HCC cohort development and verification data sets. A nomogram was constructed by integrating the risk score and clinicopathological characteristics. Finally, the influence of the gene signature on the immune microenvironment in HCC was comprehensively analyzed.Results: We found that AURKA was highly expressed in HCC, and it exhibited prognostic value. We selected eight AURKA-related genes with prognostic value through the protein-protein interaction network and successfully constructed a gene signature. The nine-gene signature could effectively stratify the risk of patients with HCC and demonstrated a good ability in predicting survival. The nomogram showed good discrimination and consistency of risk scores. In addition, the high-risk group showed a higher percentage of immune cell infiltration (i.e., macrophages, myeloid dendritic cells, neutrophils, and CD4+T cells). Moreover, the immune checkpoints SIGLEC15, TIGIT, CD274, HAVCR2, and PDCD1LG2 were also higher in the high-risk group versus the low-risk group.Conclusions: This gene signature may be useful prognostic markers and therapeutic targets in patients with HCC.

With the increasing number of automobiles on the road, passive safety has become a particularly important issue. In this paper, an energy-absorbing material, origami aluminum honeycomb, was manufactured by a welding process for use as an automobile energy absorbing box. The mechanical properties and deformation of welded origami aluminum honeycomb in three directions were studied through quasi-static and dynamic compression tests. The results show that the origami aluminum honeycomb had good mechanical energy absorption performance, and the optimal directions are identified. Combined with theoretical analysis, the errors between experiments and simulations are shown. The origami honeycomb structure was designed for use as an automobile energy absorbing box. Analysis shows that it could absorb at least 10% of the kinetic energy of a vehicle during a collision, and could play a role in protecting the interior of the vehicle.

BackgroundTimely and appropriate administration of post-exposure prophylaxis (PEP) is an essential component of human rabies prevention programs. We evaluated patient care at rabies clinics in a high-risk county in Hunan Province, China to inform strategies needed to achieve dog-mediated human rabies elimination by 2030.MethodsWe collected information on PEP, staff capacity, and service availability at the 17 rabies clinics in the high-risk county during onsite visits and key staff interviews. Additionally, we conducted observational assessments at five of these clinics, identified through purposive sampling to capture real-time information on patient care during a four-week period. Wound categories assigned by trained observers were considered accurate per national guidelines for comparison purposes. We used the kappa statistic and an alpha level of 0.05 to assess agreement between observers and clinic staff.ResultsIn 2015, the 17 clinics provided PEP to 5,261 patients. Although rabies vaccines were available at all 17 clinics, rabies immune globulin (RIG) was only available at the single urban clinic in the county. During the assessment period in 2016, 196 patients sought care for possible rabies virus exposures. According to observers, 88 (44%) patients had category III wounds, 104 (53%) had category II wounds and 4 (2%) had category I wounds. Observers and PEP clinic staff agreed on approximately half of the assigned wound categories (kappa = 0.55, p-value< 0.001). Agreement for the urban county-level CDC clinic (kappa = 0.93, p-valueConclusionRabies PEP services were available at each town of the project county; however, gaps between clinical practice and national rabies guidelines on the use of PEP were identified. We used these findings to develop and implement a training to rabies clinic staff on wound categorization, wound care, and appropriate use of PEP. Additional risk-based approaches for evaluating human rabies virus exposures may be needed as China progresses towards elimination.

The planar three-degree-of-freedom (DoF) parallel mechanism plays a significant role in the fields of automobiles and electronics due to its advantages such as high stiffness, large carrying capability, and stable operation. In this paper, a planar 3-DoF (2T1R) parallel mechanism is derived by structural evolution from the parallelogram by means of Grassmann line geometry and the Atlas method. First, the position equation of the mechanism is established and the inverse kinematics and Jacobian matrix are investigated. The maximum deviation between the theory and simulation results of the inverse kinematics and Jacobian matrix is 0.48%, which verifies the accuracy of the theoretical model. Then, the constraint conditions of the mechanism are defined. Based on the inverse position solution, the numerical method is used to solve the workspace of the mechanism. It is concluded that the ratio of the workspace to the entire triangular space is about 15% higher than that of the 3-PRR parallel mechanism. Next, based on the Jacobian matrix, the performance indexes are established to evaluate stiffness and dexterity. Finally, the size of the mechanism is optimized by means of the genetic algorithm to improve the comprehensive performance.

BackgroundCachexia is defined as an involuntary decrease in body weight, which can increase the risk of death in cancer patients and reduce the quality of life. Cachexia-inducing factors (CIFs) have been reported in colorectal cancer and pancreatic adenocarcinoma, but their value in diffuse large B-cell lymphoma (DLBCL) requires further genetic research.MethodsWe used gene expression data from Gene Expression Omnibus to evaluate the expression landscape of 25 known CIFs in DLBCL patients and compared them with normal lymphoma tissues from two cohorts [GSE56315 (n = 88) and GSE12195 (n = 136)]. The mutational status of CIFs were also evaluated in The Cancer Genome Atlas database. Based on the expression profiles of 25 CIFs, a single exploratory dataset which was merged by the datasets of GSE10846 (n = 420) and GSE31312 (n = 498) were divided into two molecular subtypes by using the method of consensus clustering. Immune microenvironment between different subtypes were assessed via single-sample gene set enrichment analysis and the CIBERSORT algorithm. The treatment response of commonly used chemotherapeutic drugs was predicted and gene set variation analysis was utilized to reveal the divergence in activated pathways for distinct subtypes. A risk signature was derived by univariate Cox regression and LASSO regression in the merged dataset (n = 882), and two independent cohorts [GSE87371 (n = 221) and GSE32918 (n = 244)] were used for validation, respectively.ResultsClustering analysis with CIFs further divided the cases into two molecular subtypes (cluster A and cluster B) associated with distinct prognosis, immunological landscape, chemosensitivity, and biological process. A risk-prognostic signature based on CCL2, CSF2, IL15, IL17A, IL4, TGFA, and TNFSF10 for DLBCL was developed, and significant differences in overall survival analysis were found between the low- and high-risk groups in the training dataset and another two independent validation datasets. Multivariate regression showed that the risk signature was an independently prognostic factor in contrast to other clinical characteristics.ConclusionThis study demonstrated that CIFs further contribute to the observed heterogeneity of DLBCL, and molecular classification and a risk signature based on CIFs are both promising tools for prognostic stratification, which may provide important clues for precision medicine and tumor-targeted therapy.

Composite ultra-thin boom can be folded elastically. Moreover, such booms are able to self-deploy by releasing stored strain energy, which can be applied in deployable antenna, solar sail, and optical telescopes. Surrogate models for imperfection-sensitive quantities of interest and multi-objective optimization are developed for the design of a new N-shape cross-section composite ultra-thin deployable boom. The proposed optimal design method integrates four general steps: (1) design of experiments, wherein the sampling designs of the N boom are created on the basis of the two-factor five-level full factorial design of experiments method; (2) efficient computational analyses of each design sample, wherein the post-buckling behavior of the N boom are analyzed under three different axial directions using nonlinear finite element ABAQUS/Explicit solver; (3) establishing the surrogate models of bending stiffness around the $x$ -and $y$ - axes and torsional stiffness around the $z$ -axis by response surface method (RSM); (4) performing the multi-objective optimization design using modified non-dominated sorting genetic algorithm to realize the optimal design. The bending stiffness around the $x$ -and $y$ - axes and the torsional stiffness around the $z$ -axis are set as the objectives, mass is set as the constraint, and the bonded web height and the central angle of the middle tape spring of the N boom are set as the variables. The typical surrogate modeling method can be applied to different problems in structural and material design.

To meet the needs of large space telescopes, such as light weight, high folding ratio, and low manufacturing cost, a flexible deployable regular hexagonal membrane sunshield is proposed in this paper. Firstly, the dynamic equation of the membrane plane is established by the micro-element method. Then, the response surface method is used to obtain the mathematical model of the fundamental frequency of the membrane sunshield. The factors influencing this model, such as the corner pulling force, the effective circle radius, and the edge arch height, are analyzed. By combining the formula of the fundamental frequency of the membrane sunshield and the effective area ratio of the sunshield, the multi-objective optimization function of the fundamental frequency of the membrane sunshield is obtained. A scaled-down experimental prototype of the membrane sunshield is built, and the modal test is performed on the thin membrane plane with a circular fixed boundary in the middle. Comparing the experimental results with the finite element simulation results, the mode shape and the fundamental frequency are highly consistent. This proves that the model can be used to solve the fundamental frequency of the membrane sunshield under the same boundary.

For large bearing capacity and low current consumption of the magnetic suspension platform, a 2-DOF electromagnetic actuator with a new structure of halbach array is proposed to improve driving force coefficients. The structure and the working principle are introduced. An accurate sub domain model of the new structure is established to accurately and rapidly calculate the magnetic field distribution for obtaining the parameters and performance of the electromagnetic actuators. The analytical model results are verified by the finite element method. The force/torque model of the magnetic suspension platform is established based on the proposed 2-DOF electromagnetic actuator. Three position-sensitive detectors and six accelerometers are applied to perceive in real time the posture and vibration acceleration of the platform, respectively. Their hardware information is introduced and measurement models are established based on the layout. Finally, the electromagnetic characteristics of the proposed actuator are investigated and compared with the conventional counterpart by finite element analysis. The results show that the average magnetic field, 0.432 T, horizontal and vertical force coefficient, 92.3 N/A and 30.95 N/A, and torque in x and z direction, 3.61 N·m and 8.49 N·m, of the proposed actuator are larger than those of the conventional one.

In this paper, the stress superposition method (SSM) is proposed to solve the stress distribution of regular polygon membranes. The stress-solving coefficient and the calculation formula of arbitrary point stress of regular polygon membrane are derived. The accuracy of the SSM for calculating stresses in regular polygonal membranes is verified by comparing the calculation results of the SSM with the finite element simulation results. This article is the first to propose a method to investigate the response of the arch height of the membrane curved edge to the membrane’s mechanical properties while keeping the effective area constant. It is found that the equivalent stress and the second principal stress at the midpoint of the membrane curved edge are effectively increased with the increase of the arch height of the curved edge. The second principal stress at the edge region of the membrane is relatively small, leading to the occurrence of wrinkles. When the stress at the midpoint of the curved edge is equal to that at the center of the membrane, the membrane plane attains the maximum stiffness and reduces the possibility of wrinkling at the edge.

The detonation wave propagation characteristics in micro-scale groove charges are very important for optimizing the structure of the Micro-Electro-Mechanics System explosive train and improving its detonation reliability. Focusing on the problem of detonation wave propagation of micro-scale groove charges under strong confinement, the effects of charge density, groove size and confinement are considered. A theoretical model of curved detonation wave propagation in a micro-scale groove charge under a strong confinement was established by means of equivalent mass correction. The mathematical expression for the detonation velocity was derived and a numerical calculation method of detonation velocity and shock front shape was given using MATLAB software. An experiment was designed to test the detonation velocities for micro-scale groove charges with a booster explosive. The results closely agreed with the calculations, validating the propagation model of curved detonation waves. The results show that the smaller the groove size, the bigger the detonation velocity loss and the curvature of shock front in the central axis. When the charge size was 0.6×0.6mm, the detonation velocity loss was 11.49%. The detonation velocity and maximum streamline deflection angle increase with increasing charge density and size. The increase of streamline deflection angle reduces the detonation velocity of the explosive. However, the streamline deflection angle changes by only a small amount in the micro-scale with an effect on the detonation velocity of less than 1%. The detonation velocity has a strong correlation with charge size and density. This paper contains theoretical guidance for the design and performance optimization of charge structures in the MEMS explosive train.

The modular magnetic suspension platform depends on multi degree of freedom of Lorentz force actuators for large bearing capacity, high precision positioning and structure miniaturization. To achieve the integration of vertical driving force and horizontal driving force, a novel 2- (two degrees-of-freedom) DOF Lorentz force actuator is developed by designing the pose of the windings and permanent magnets (PMs). The structure and the working principle are introduced. The electromagnetic force mathematical model is established by the equivalent magnetic circuit method to analyze the coupling of magnetic flux. The distribution characteristics of magnetic flux density are analyzed by the finite-element method (FEM). It is found that the coupling of the magnetic flux and the large magnetic field gradient severely reduce the uniformity of the air-gap magnetic field. The electromagnetic force characteristic is investigated by FEM and measurement experiments. The difference between FEM and experiment results is within 10%. The reasons of driving force fluctuation are explained based on the distribution of air-gap magnetic field. The actuator performance are compared under the sliding mode control algorithm and PID control algorithm and the positioning accuracy is 20 μm and 15 μm respectively. Compared with the similar configuration, the motion range and force coefficient of the Lorentz force actuator in this paper are larger. It has a certain guiding significance on the structure design of the multi degree of freed Lorentz force actuator.

This study proposes deployable units driven by elastic hinges and a double-layer hoop deployable antenna composed of these units. A rational modeling method based on the energy equivalence principle is presented to develop an equivalent model of the double-layer hoop antenna in accordance with the structural characteristics of the antenna. The equivalent beam models of the rods with elastic hinges are proposed. The relationship of geometrical and material parameters is established considering the strain energy and the kinetic energy of the periodic unit, which are the same as those of the equivalent beam in the same displacement field. The equivalent model of the antenna is obtained by assembling several equivalent beam models in the circumferential direction. The precision of the equivalent model of the antenna is acceptable as found by comparing the modal analysis results obtained through equivalent model calculation, finite element simulation, and modal test.

To meet space science experiments in micro-gravity environment, micro-spacecraft vibration isolation technology was developed in recent years. A new kind of 2-degree-of-freedom electromagnetic actuator based on Lorentz principle was developed in this article. The composition and working principle of the actuator were introduced, the parametric model for electromagnetic actuator was established, the structural optimization was carried out with the help of genetic algorithm in the MATLAB toolbox, and the final optimal structural parameters were obtained. For achieving the magnetic induction intensity in radial and axial directions, theoretical model for electromagnetic characteristics of the 2-degree-of-freedom actuator was established, and the expression for electromagnetic force was obtained. A static electric–magnetic coupling simulation of the whole actuator and also the experiments for measuring magnetic induction and magnetic force were carried out, and the correctness of theoretical model was verified.

High precision measurement of acceleration levels is required to allow active control for vibration isolation platforms. It is necessary to propose an accelerometer configuration measurement model that yields such a high measuring precision. In this paper, an accelerometer configuration to improve measurement accuracy is proposed. The corresponding calculation formulas of the angular acceleration were derived through theoretical analysis. A method is presented to minimize angular acceleration noise based on analysis of the root mean square noise of the angular acceleration. Moreover, the influence of installation position errors and accelerometer orientation errors on the calculation precision of the angular acceleration is studied. Comparisons of the output differences between the proposed configuration and the previous planar triangle configuration under the same installation errors are conducted by simulation. The simulation results show that installation errors have a relatively small impact on the calculation accuracy of the proposed configuration. To further verify the high calculation precision of the proposed configuration, experiments are carried out for both the proposed configuration and the planar triangle configuration. On the basis of the results of simulations and experiments, it can be concluded that the proposed configuration has higher angular acceleration calculation precision and can be applied to different platforms.

The energy transport inside a phase change material (PCM) based thermal energy storage system using metal foam as an enhancement technique is investigated numerically. The paraffin is used as the PCM and water as the heat transfer fluid (HTF). The transient heat transfer during the charging and discharging processes is solved, based on the volume averaged conservation equations. The flow in PCM/foam and HTF/foam composites is modelled by the Forchheimer-extended Darcy equation, while the two-temperature model is employed to account for the local thermal non-equilibrium effect between the foam matrix and fluid phase. The results show that the overall performance is greatly improved by inserting metal foam in both HTF and PCM sides. A nearly 84.9% decrease in the time needed for the total process is found compared with the case of pure PCM, and 40% compared with the case of metal foam insert only in the PCM side. Foam porosity and HTF inlet temperature greatly affect the dynamic heat storage/release process.

Forced flow and radiation-convection coupled heat transfer in an annulus filled with open-cell foam was numerically investigated at high temperatures. The Darcy-Brinkman-Forchheimer model was utilized to represent the fluid transport. The two-energy equation model was applied for the non-equilibrium heat exchange between the fluid and solid phases, while the radiation heat transfer within the foam material was solved using the P1 approximation. Two different cases of thermal boundary conditions were studied and discussed in detail, namely the inner wall with a constant heat flux while the outer wall was adiabatic (case I) and vice versa (case II). The effects of pertinent factors on the heat transfer characteristics were examined, such as the foam structural parameters and the radii ratio of the annulus. The temperature, local and average Nusselt number were predicted. The results indicate that neglecting the thermal radiation causes a large deviation in predicting the thermal performance of such foam-fluid systems. Increasing the porosity and pore diameter both promote the radiation heat transfer, while it is weakened by increasing the radii ratio. The average Nusselt number decreases as the porosity increases, while it exhibits a non-monotonic change with the pore diameter and radii ratio. Besides, case I shows a higher average Nusselt number than case II and presents an improved thermal performance.

In this paper, a systematic method to synthesize parallel mechanisms for feed support mechanisms based on screw theory is proposed. First, the motion requirement of the feed support mechanism is studied. Then, a class of parallel mechanisms having a translational motion with different degrees of freedom is synthesized based on the constraint-synthesis method. Then, these parallel mechanisms are modified based on the specificities of deployable mechanisms, and two kinds of mechanisms are selected as the unit for the feed support mechanism. Finally, the deployment ratio of two kinds of mechanisms is optimized. The configurations obtained in this paper can enrich the types of feed support mechanisms.

Compared with the fixed morphological robots, the self-reconfigurable robots (SR) are very flexible as they can adapt to a wide range of task requirements. However, the current efforts on SR mainly focus on the locomotion issues, while the manipulation capabilities of existing systems are still quite limited. In this paper, a new kind of mobility reconfigurable robotic structures (MRRS) with self-reconfiguration ability is presented. The reconfigurable topology and variable mobility characteristics of the MRRS are realized by integrating the cooperative kinematic mechanism (CKM) and the separable parallel kinematic mechanism (SPKM) into one robotic system, which makes the robot capable of reconfiguring its mechanical assembly to adapt to the multiple motion task requirements. Based on Lie group of displacements, the commonly used robotic tasks are first classified into three categories: positioning motion, tooling motion and grasping motion, possible motion types of these tasks are enumerated, then how to deal with the multiple tasks by using the MRRS is synthesized systematically. Finally, a multi-task working process is employed as an example to illustrate the advantages of this reconfigurable robotic structure.

The microvibration has a serious impact on science experiments on the space station and on image quality of high resolution satellites. As an important component of the active vibration isolation platform, the maglev actuator has a large stroke and exhibits excellent isolating performance benefiting from its noncontact characteristic. A maglev actuator with good linearity was designed in this paper. Fundamental features of the maglev actuator were obtained by finite element simulation. In order to minimize the coil weight and the heat dissipation of the maglev actuator, parametric design was carried out and multiobjective optimization based on the genetic algorithm was adopted. The optimized actuator has better mechanical properties than the initial one. Active vibration isolation platforms for different-scale payload were designed by changing the arrangement of the maglev actuators. The prototype to isolate vibration for small-scale payload was manufactured and the experiments for verifying the characteristics of the actuators were set up. The linearity of the actuator and the mechanical dynamic response of the vibration isolation platform were obtained. The experimental results highlight the effectiveness of the proposed design.

Clearance joints significantly affect the dynamic properties of deployable structures (DSs). This paper presents a spring-mass model with clearance for the study of the axial stiffness of a jointed structure. The nonlinear stiffness can be predicted by calculating the model's natural frequency which is the reciprocal of the motion period of the model. The results of the theoretical model show that the dynamic stiffness of the clearance joint increases with increases in the displacement amplitude; this finding is consistent with the experimental results. With the inclusion of sliding factors, contact friction, and impact, the established model of energy dissipation is useful for estimating the effects of joint damping on DSs. The energy dissipation model reveals the effects of joint features and excitation conditions on the dissipation of the jointed structure, that is, the excitation frequency and amplitude. Dynamic experiments were performed on jointed structures to characterize the dissipation variations. An exponentially fitting equation was developed based on the energy dissipation model and was verified through the experimental data. This formulation is more efficient than numerical integration for the calculation of the energy dissipation.