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The experimental research was carried out to reveal the feasibility of induction heating fused wire continuous deposition forming of 7075 aluminum alloy. Single-channel, single-layer and multi-layer forming processes were investigated respectively. The influences of printing speed, filling height, substrate temperature and filling spacing on forming quality were studied, and the performance of the forming sample was tested and analyzed. The results show that in the single-channel forming experiment, the printing speed has the most significant effect on the melting width and melting height. With the increase of the printing speed, the melting height and melting width are reduced, and the reduction rate is gradually slow. The effect of filling height on melting height and melting width is not obvious. When the substrate temperature is 600 °C, the fusion performance between the forming melt and the substrate is the best. In the single-layer forming experiment, the filling spacing has obvious influence on the bonding effect between the melting channel, and the substrate temperature has great influence on the uniformity and overall quality of the melting channel. In the multi-layer forming experiment, the overlapping between the layers of the forming sample is dense, and the overall fusion performance of the sample is good. The overall hardness fluctuation range is about 65∼78HV, and its tensile strength reaches 184 MPa, which is about 57.3% of the tensile strength of the aluminum substrate. The research results of this paper demonstrate the feasibility of the additive manufacturing method of induction heating fused wire continuous deposition.

Hazardous materials pose significant dangers during transportation due to their flammable and explosive properties. The consequences of accidents involving such materials are often severe and irreparable. A well-designed hazardous materials transportation network can mitigate these risks. However, designing such a network presents two major challenges: quantifying the risk associated with hazardous materials transportation and addressing the hierarchical relationship between government and companies. To address these challenges, we enhance the accuracy of accident probability estimates and the comprehensiveness of accident consequence assessments, incorporating the uncertainty of accident outcomes. We propose a comprehensive risk assessment model and develop a bilevel programming model to reflect the hierarchical relationship. In this model, the government at the upper level aims to minimize the total risk, while companies at the lower level seek to minimize their total costs. The model is transformed using chance-constrained programming and solved using heuristic algorithms. We apply the model to the highway network in Anhui province, China, to verify its validity. The results demonstrate that the model effectively manages the hierarchical relationship between government and companies, reduces the risk of hazardous materials transportation, and enhances the stability and safety of the transportation network.

Abstract The success of blockchain technology in cryptocurrencies reveals its potential in the data management field. Recently, there is a trend in the database community to integrate blockchains and traditional databases to obtain security, efficiency, and privacy from the two distinctive but related systems. In this survey, we discuss the use of blockchain technology in the data management field and focus on the fusion system of blockchains and databases. We first classify existing blockchain-related data management technologies by their locations on the blockchain-database spectrum. Based on the taxonomy, we discuss three types of fusion systems and analyze their design spaces and trade-offs. Then, by further investigating the typical systems and techniques of each type of fusion system and comparing the solutions, we provide insights of each fusion model. Finally, we outline the unsolved challenges and promising directions in this field and believe that fusion systems will take a more important role in data management tasks. We hope this survey can help both academia and industry to better understand the advantages and limitations of blockchain-related data management systems and develop fusion systems that meet various requirements in practice.

An infrared photodetector is a critical component that detects, identifies, and tracks complex targets in a detection system. Infrared photodetectors based on 3D bulk materials are widely applied in national defense, military, communications, and astronomy fields. The complex application environment requires higher performance and multi-dimensional capability. The emergence of 2D materials has brought new possibilities to develop next-generation infrared detectors. However, the inherent thickness limitations and the immature preparation of 2D materials still lead to low quantum efficiency and slow response speeds. This review summarizes 2D/3D hybrid van der Waals heterojunctions for infrared photodetection. First, the physical properties of 2D and 3D materials related to detection capability, including thickness, band gap, absorption band, quantum efficiency, and carrier mobility, are summarized. Then, the primary research progress of 2D/3D infrared detectors is reviewed from performance improvement (broadband, high-responsivity, fast response) and new functional devices (two-color detectors, polarization detectors). Importantly, combining low-doped 3D and flexible 2D materials can effectively improve the responsivity and detection speed due to a significant depletion region width. Furthermore, combining the anisotropic 2D lattice structure and high absorbance of 3D materials provides a new strategy in high-performance polarization detectors. This paper offers prospects for developing 2D/3D high-performance infrared detection technology.

The Wingless-type protein 7a (Wnt7a) plays an antiproliferative role in non-small-cell lung cancer (NSCLC). Previous studies have indicated that Wnt7a expression was downregulated in radiation-resistant NSCLC cells. However, little is known about its biological functions and molecular mechanisms in radiosensitivity of NSCLC. Thus, NSCLC cell proliferation and apoptosis in response to Wnt7a overexpression and/or radiation were determined by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl-tertazolium bromide (MTT) assay and flow cytometry, respectively. The activation of the Wnt/cJun N-terminal kinase (JNK) and Wnt/β-catenin signaling pathways were further examined by western blot in NSCLC cell lines H1650 and A549. Wnt7a overexpression combined with radiation-inhibited cell proliferation and induced apoptosis in NSCLC cell lines compared to Wnt7a overexpression or radiotherapy alone. In addition, the phosphorylation of JNK, but not β-catenin, was congruent with the changes in Wnt7a overexpression and/or radiation. Moreover, the Wnt/JNK pathway could induce the apoptosis of NSCLC cells through the mitochondrial pathway. Inhibition of the Wnt/JNK signaling pathway by SP600125, a JNK inhibitor, contributed to proliferation induction in NSCLC cells. Taken together, these results showed that Wnt7a overexpression sensitized NSCLC cell lines to radiotherapy through the Wnt/JNK signaling pathway.

Abstract Background Evidence from quantitative studies suggest that Tai Chi produces a variety of health-related benefits, but few qualitative studies have investigated how older adults perceive the benefit of Tai Chi. The objective of the current study was to qualitatively evaluate the perceived benefits of Tai Chi practice among community older population. Methods This study was conducted with participants from a trial examining the effects of a 12-week Tai Chi training on ischemic stroke risk in community older adults (n = 170). A total of 20 participants were randomly selected from a convenience sample of participants who had completed 12-week Tai Chi training (n = 68) were interviewed regarding their perceived benefit on physical and mental health and whether Tai Chi exercise was suitable for the elderly. Results All participants agreed that Tai Chi training could relax their body and make them comfortable. Most of them thought Tai Chi training could promote physical health, including relieving pain, enhancing digestion, strengthening immunity, enhancing energy and improving sleep quality, enhancing their mental and emotional state (e.g. improving mood and reducing anxiety, improving concentration and promoting interpersonal relationship). Most of participants also agreed that Tai Chi exercise was appropriate for community older people. Three primary themes emerged from content analysis: Improving physical health; Enhancing mental and emotional state; Conforming with the request of the elderly. Conclusion The findings indicate that regular Tai Chi exercise may have positive benefits in terms of improved physical health and mental state among community elderly population, and may be useful and feasible body-mind exercise to community elderly population for its positive effects and advantages. Trial registration ChiCTR ChiCTR-TRC-13003601 . Registered 23 July 2014.

In geotechnical reliability analysis, random volatility in marginal distributions of shear strength parameters has been rarely considered. Unfortunately, conventional marginal distribution models cannot characterize real probability distribution accurately, leading to considerable dispersion with incomplete probabilistic information. In this paper, an estimation methodology is proposed based on copula theory coupling information diffusion technique. Firstly, information diffusion distribution is extended to represent one-dimensional marginal distributions of shear strength parameters. Secondly, copula theory is employed to characterize the dependence structures among the parameters. Eventually, equivalent sample is yielded by information diffusion distribution that has been already established. A case study in Singapore is implemented to enunciate and validate the competence of the proposed method. The performances of the candidate copulas coupling different marginal distributions are further discussed. Results indicate that information diffusion distribution can efficiently capture the random volatility of real distributions of shear strength parameters and hold remarkable superiority in modeling marginal distributions. The equivalent sample, estimated by information diffusion technique in conjunction with Gaussian copula, has considerable consistency with original data. The proposed method can provide a reference to reliability analysis in geotechnical engineering.

To investigate the effectiveness and safety of Tai Chi Chuan (TCC) on physical and psychological health of college students.Two hundred six college students were recruited and randomly allocated to a control group or a TCC exercise group in an equal ratio. Participants in the control group were instructed to maintain their original activity level and those in the TCC exercise group received 12 weeks of TCC exercise training based on their original activity level. Physical and psychological outcomes were evaluated at baseline, 13 weeks and 25 weeks. Intention-to-treat analysis was performed for the above outcomes.Compared with the control group, the TCC exercise group showed significant improvements at the end of the 12-week intervention period for flexibility (length of Sit and Reach (cm): TCC group 14.09±7.40 versus control 12.88±6.57, P = 0.039 adjusted for its baseline measures using a general linear model) and balance ability (open eyes perimeter: TCC group 235.6(191~314) versus control 261(216~300); closed eyes perimeter: TCC group 370.5 (284~454) versus control 367 (293~483); P = 0.0414, 0.008, respectively, adjusted for corresponding baseline measures using a general linear model). No significant changes in other physical and mental outcomes were found between the two groups. No adverse events were reported during the study period.TCC exercise was beneficial in college students for improving flexibility and balance capability to some extent, compared with usual exercise.Chinese Clinical Trial Registry ChiCTR-TRC-13003328.

The physical and mental health of college students tends to continuously decline around the world, therefore, it is important to improve their health during college period. Baduanjin, a traditional Chinese exercise which combines movements with breath and mind, may be one of the selectable effective exercises. However, the effect of Baduanjin exercise on college students has not been established. In this study, we systematically assessed the effectiveness and safety of Baduanjin exercise on physical and mental health of college students by a rigorous randomized, parallel-controlled design.A total of 222 college students from Fujian University of Traditional Chinese Medicine were recruited and randomly allocated at an equal ratio into control or Baduanjin training. Participants in control group were informed to maintain their original activity habit, and those in Baduanjin exercise group received a 12-week Baduanjin exercise training with a frequency of 1 hour per day and 5 days per week on the basis of their original activity habit. The physical and psychological outcomes, including lumbar muscle strength, lower limb proprioception function, physical fitness, as well as self-reported symptom intensity, stress, self-esteem, mood, quality of life, quality of sleep, and adverse events, were evaluated at baseline, 13 weeks (at the end of 12-week intervention), and 25 weeks (after the 12-week follow-up period). Intention-to-treat analysis was performed for the above outcomes.Compared with controls, significant improvements in Baduanjin exercise group at the end of 12-week intervention period were found on lower limb proprioception function (the rate of average trace error on right lower limb (%): control 23.50±5.50, Baduanjin 21.92±6.54, P=0.004; the rate of average trace error on left lower limb (%): control 22.32±6.62, Baduanjin 20.63±4.62, P=0.046), cardiorespiratory endurance (step test index: control 47.66±5.94, Baduanjin 50.07±9.30, P=0.025), flexibility (control 14.35±7.26cm, Baduanjin 15.39±6.43cm, P=0.009) and explosive force of lower limb (standing long jump test (m): control 1.77±0.24, Baduanjin 1.79±0.22, P=0.005 for adjustment baseline) in physical outcomes, and attention (Schulte Grid test (second): control 210.4±51.15, Baduanjin 192.4±47.14, P=0.034) in mental outcome. Lumbar muscle strength in Baduanjin group had been moderately enhanced but no significant difference compared to controls. No significant changes in other physical and mental outcomes, including vital capacity, blood pressure, heart rate, hand grip force, self-symptom intensity, stress, self-efficacy, quality of life, and quality of sleep, were found between groups. No adverse event was reported during the study period.Regular Baduanjin exercise had an advantage for college students on improvement of lower limb proprioception, enhance of cardiorespiratory endurance, flexibility, explosive force of lower limb and attention, compared with usual exercise.Chinese Clinical Trial Registry ChiCTR-TRC-13003329 http://www.chictr.org.

Magnesium oxysulfide (MOS) cement has emerged as a promising cementitious material due to the high strength and excellent durability, but research on its rust inhibition remains limited. In this study, the chloride and nitrite were introduced in the MOS cement composites, aiming to investigate the corrosion properties and reveal the rust inhibition mechanism of steel bar under different W/C ratio. Experimental results show that the corrosion area ratios reach the largest value of approximately 98% and the lowest value of approximately 3%, respectively, as the chloride and nitrite contents increase to 2%. Compared with chloride, the effect of W/C ratio on the mass loss of steel bar is gradually weakened when the nitrite content is larger than 0.5%. Based on the natural potential, the change of corrosion degree mainly occurs after 28d. In addition, the corrosion potential of steel bar decreases and corrosion rate increases with the increase of chloride content in MOS cement composites. Conversely, the presence of Mg(NO2)2 from nitrite engenders an opposite effect. Besides, the increase of W/C ratio results in higher electrochemical parameters. At this time, the rust inhibition mechanism is revealed based on the micro-structure analysis.

This study investigated the effects of Tai Chi compared with no exercise control on the cerebral hemodynamic parameters and other health-related factors in community older adults at risk of ischemic stroke. A total of 170 eligible participants were randomly allocated to Tai Chi or control group. The cerebral hemodynamic parameters and physical fitness risk factors of cardiovascular disease were measured at baseline, 12 weeks, and 24 weeks. After the 12-week intervention, Tai Chi significantly improved the minimum of blood flow velocity (BFVmin); BFVmean; pulsatility index and resistance index of the right anterior cerebral artery; and BFVmax, BFVmin, and BFVmean parameters of the rightmiddle cerebral artery. Tai Chi training also decreased triglyceride, fasting blood glucose, and homocysteine levels, and improved balance ability. Therefore, the supervised 12-week Tai Chi exercise had potential beneficial effects on cerebral hemodynamics, plasma risk factors, and balance ability in older community adults at risk of ischemic stroke. [ABSTRACT FROM AUTHOR]

Since 3D printed structure is conducted by the style of dimension reduction, the defects typically occur between the printing layers due to the poor rheological properties, which affects the durability most. This study focuses on exploring the durability of 3D printed calcium sulphoaluminate cement-based materials (CSACMs) with slag powder based on the correlation between printed structures and rheological parameters. Experimental results show that both the static and dynamic yield stress of 3D printed CSACMs exhibits a gradual increase with the slag powder content increases, while the thixotropy improves continually until reaching a maximum content at 15%. In this case, an increase in slag powder content leads to a significant reduction for structure deformation. However, poor printability occurs when the content of slag powder exceeds 15%. Besides, the chloride migration coefficient and maximum electric flux decreases from 7.28 × 10−12 to 3.27 × 10−12 m2/s and 1347 to 711 K, respectively, when the content of slag powder increases from 0 to 10%. Meanwhile, the freezing resistance and linear shrinkage are improved. Based on the radar map correlation, structure deformation is significantly influenced by thixotropy, which is a crucial factor that can impact the durability of 3D printed CSACMs. In conclusion, the controllable rheology of 3D printed CSACMs are advantageous for improving the printed structures and durability.

N1-methyladenosine (m1A) modification is a crucial post-transcriptional regulatory mechanism of messenger RNA (mRNA) in living organisms. Few studies have focused on analysis of m1A regulators in lower-grade gliomas (LGG). We employed the Nonnegative Matrix Factorization (NMF) technique on The Cancer Genome Atlas (TCGA) dataset to categorize LGG patients into 2 groups. These groups exhibited substantial disparities in terms of both overall survival (OS) and levels of infiltrating immune cells. We collected the significantly differentially expressed immune-related genes between the 2 clusters, and performed LASSO regression analysis to obtain m1AScores, and established an m1A-related immune-related gene signature (m1A-RIGS). Next, we categorized all patients with LGG into high- and low-risk subgroups, predictive significance of m1AScore was confirmed by conducting univariate/multivariate Cox regression analyses. Additionally, we confirmed variations in immune-related cells and ssGSEA and among the high-/low-risk subcategories in the TCGA dataset. Finally, our study characterized the effects of MSR1 and BIRC5 on LGG cells utilizing Edu assay and flow cytometry to explore the effects of modulation of these genes on glioma. The results of this study suggested that m1A-RIGS may be an excellent prognostic indicator for patients with LGG, and could also promote development of novel immune-based treatment strategies for LGG. Additionally, BIRC5 and MSR1 may be potential therapeutic targets for LGG.

Neutrophils are important inflammatory effector cells that protect against foreign invasion but also cause self-harm. Numerous neutrophils infiltrate the lungs in acute respiratory distress syndrome/acute lung injury (ARDS/ALI) patients. However, the exact impact of neutrophil infiltration on ARDS's onset and progression remains unclear. To investigate this, we analyzed two ARDS-related datasets from the Gene Expression Omnibus public database and discovered an association between CD177, a neutrophil-specific surface protein, and ARDS progression. We used quantitative flow cytometry to assess CD177+ neutrophils in the peripheral blood of clinical ARDS patients versus healthy controls, finding a significant increase in CD177+ neutrophils percentage among total neutrophils in ARDS patients. This finding was further confirmed in ALI mouse models. Subsequent animal experiments showed that anti-CD177 effectively reduces pulmonary edema, neutrophil infiltration, and inflammatory cytokine release, along with a decrease in reactive oxygen species (ROS) and myeloperoxidase (MPO) levels. We also established an in vitro co-culture system to mimic neutrophil and lung epithelial cell interactions. In the anti-CD177 group, we observed decreased expression of NLRP3, caspase 1, PAD4, MPO, and ROS, along with a reduction in certain inflammatory cytokines. These results indicate a crucial role for the CD177 gene in ARDS's development and progression. Inhibiting CD177 may help mitigate excessive activation of NLRP3 inflammasomes, ROS, and neutrophil extracellular traps (NETs), thus alleviating ARDS.

Abstract Ruthenium (Ru) has been regarded as one of the most promising alternatives to substitute Pt for catalyzing alkaline hydrogen evolution reaction (HER), owing to its inherent high activity and being the cheapest platinum‐group metal. Herein, based on the idea of strong metal–support interaction (SMSI) regulation, Ru/TiN catalysts with different degrees of TiN overlayer over Ru nanoparticles were fabricated, which were applied to the alkaline electrolytic water. Characterizations reveal that the TiN overlayer would gradually encapsulate the Ru nanoparticles and induce more electron transfer from Ru nanoparticles to TiN support by the Ru–N–Ti bond as the SMSI degree increased. Further study shows that the exposed Ru–TiN interfaces greatly promote the H2 desorption capacity. Thus, the Ru/TiN‐300 with a moderate SMSI degree exhibits excellent HER performance, with an overpotential of 38 mV at 10 mA cm−2. Also, due to the encapsulation role of TiN overlayer on Ru nanoparticles, it displays super long‐term stability with a very slight potential change after 24 h. This study provides a deep insight into the influence of the SMSI effect between Ru and TiN on HER and offers a novel approach for preparing efficient and stable HER electrocatalysts through SMSI engineering.

The integrin subunit α3 (ITGA3) is a member of the integrin alpha chain protein family, which could promote progression, metastasis, and invasion in some cancers. Still, its function in the tumor microenvironment (TME), cancer prognosis, and immunotherapy remains unclear. A multifaceted analysis of ITGA3 in pan-cancer utilizing various databases and online web tools revealed ITGA3 was aberrantly expressed in tumor tissues and upregulated in most cancers, which may be related to ITGA3 genomic alterations and methylation modification. In addition, ITGA3 was significantly correlated with the poor or better prognosis of cancer patients, immune-related pathways in hallmark, immune infiltration, and immune checkpoints, revealing a biological function of ITGA3 in the tumor progression, tumor microenvironment, and tumor immunity. We also found that ITGA3 could predict the response to tumor immunotherapy based on cytokine-treated samples and immunotherapy cohorts. ITGA3 may participate in shaping and regulating the tumor microenvironment to affect the tumor immune response, which was a promising immunotherapy response predictive biomarker and potential therapeutic target to work synergistically with cancer immunotherapy to boost the response and efficacy. Finally, potential targeted compound inhibitors and sensitive drugs were screened using databases ConnectivityMap (CMap) and CellMiner, and AutoDock Tools was used for molecular docking.

The study of the mechanical properties of frozen rock is a basic problem that humans have to face in artificial low-temperature rock engineering and cold region rock engineering. There are few literatures on the dynamic constitutive models of frozen rocks under low-temperature gradients at home and abroad. In this paper, the constitutive model of water-saturated marble under the coupling effects of uniaxial impact compressive load and low-temperature is studied by theoretical analysis and experimental verification. Based on the theory of mechanical element combination, a rock constitutive model considering strain rate effect, damage softening effect and low-temperature effect is established, and the model parameters are determined by fitting method. The dynamic stress-strain curve of water-saturated marble at -30 ℃ is predicted. The predicted results are in good agreement with the experimental results and the concordance correlation coefficient is 0.984092. The relevant results of this paper can provide a theoretical reference for the excavation and protection of rock engineering under negative temperature. [ABSTRACT FROM AUTHOR]

Abstract Background The p21-activated kinase (PAK) family (PAKs) plays a key role in the formation and development of human tumors. However, a systematic analysis of PAKs in human cancers is lacking and the potential role of PAKs in cancer immunity has not been explored. Methods We used datasets from in The Cancer Genome Atlas (TCGA) database and Genotype-Tissue Expression database (GTEx). Results Based on TCGA datasets most PAKs show noteworthy differences in expression between tumors and corresponding normal tissues or across different tumor tissues. Patients with high expression of PAKs often show a worse prognosis. However, copy number variation, mutation, and DNA methylation of PAKs have limited impact on tumor development. Further analysis showed that the impact of PAKs on immunity varies with the type of tumor and the respective tumor microenvironment. PAK1 and PAK4 may be stronger predictors of immune characteristics, and are more suitable as drugs and molecular therapeutic targets. Furthermore, Cox regression analysis revealed that a PAK gene signature could be used as an independent prognostic factor for lower grade glioma (LGG) and glioblastoma (GBM). Gene set enrichment analysis (GSEA) analysis indicated that PAK genes may affect the occurrence and development of GBM through the PI3K signaling pathway. Further experiments verified that PAK1 and AKT1 have a significant interaction in GBM cells, and inhibiting the overactivation of PAK1 can significantly inhibit the proliferation of GBM cells. Conclusions Our study provides a rationale for further research on the prognostic and therapeutic potential of PAKs in human tumors.

Developing advanced cathode materials to achieve the high-power applications is an important technology for the rechargeable lithium-ion batteries. In this work, hierarchical LiMnPO4 microspheres are designed and fabricated using MnCO3 microspheres as the self-sacrificial template. The novel hierarchical structure with high tap density and more exposed active sites is favorable for the electrolyte penetration and also provides sufficient contact areas for fast Li-ion intercalation and deintercalation reaction. In addition, the uniform thin carbon layer extending from the interior to the outside of the LiMnPO4 microsphere, could further construct a conductive and robust carbon network, which will inevitably accelerate the transport of electrons and improve the discharge capacity. Specifically, a high reversibility capacity of 158.4 mAh g-1 at 0.05 C and 104.3 mAh g-1 at 5 C is achieved. Furthermore, the superior capacity retention with 98% after 200 cycles at 5 C is maintained, revealing an excellent cycle stability. This work may open up a promising strategy to prepare other advanced electrode materials. [ABSTRACT FROM AUTHOR]

Considering parameters of corrosion area ratio and mass loss degree, the half-cell potential method and linear polarization method were applied to study the corrosion state of steel bars under the influence of carbonation, chloride salt and compound environmental action. X-ray photoelectron spectroscopy (XPS) was used to measure steel corrosion under coupling action and the effect of sodium nitrite rust inhibitor in the compound environment was studied. The results show that the corrosion rate of steel under carbonation, chloride salt and compound environment increases in the beginning and then decreases. In the chloride environment, sufficient moisture inside the concrete at the initial stage of curing induces a faster corroding. With the destruction of the passive film on the surface of the steel bars together with the balance of internal and external humidity, the corrosion rate tends to stabilize. At the following curing stage, the corrosion rate decreases as the degree of steel corrosion increases and the corrosion layer is formed. Carbonation reduces the alkalinity around the passive film and damages the passive film, which accelerates the corrosion happening. The following development of the corrosion layer of steel bars limits the corrosion rate. The corrosion degree in the compound environment is more serious than that under the condition of single factor action. Under electrochemical action, the order of product components resulting from steel corrosion are Fe2O3, Fe3+-Ca2SiO4 and FeO from high to low. Nitrite oxidizes the unstable Fe2+ into stable Fe3+ and precipitates on the surface of the steel to form a passivation film, which has a good anti-rust effect.

Due to the development of aviation hydraulic systems towards high pressure and high flow, the frequency range of pressure pulsation becomes wider, and the amplitude of pulsation increases. This puts higher requirements on the attenuation characteristics of the pressure pulsation attenuator. To reduce the damage caused by pressure pulsation to the pipeline, a Helmholtz-type pulsation attenuator (HTPA) is designed, which works through the Helmholtz resonant chamber. The theoretical model of HTPA is established by the method of lumped parameter method and distribution parametric method. The insertion loss is adopted to evaluate its attenuation characteristics. The internal pressure dynamic characteristics and attenuation effect of the HTPA are analyzed by simulation and experimentation. The results show that the pulsation attenuation rate δ was 40% after the installation of the attenuator. In the frequency range of 0–1000 Hz, the maximum insertion loss is 19 dB, which verifies the validity and correctness of the theoretical model.

Glioma is a common intracranial malignancy in adults and has a high mortality due to its poor prognosis and high recurrence rate. Dysregulation of protein degradation is one of the main promoting factors in glioma development. As an indispensable unit of the proteasome, Proteasome 20S Subunit Beta 9 (PSMB9) is one of the major enzymes in ubiquitin-dependent protein degradation in cells. In addition, proteasomes also participate in a series of cellular processing, like immune regulation, nerve signal transduction, material transport through channels, cell adhesion, and various signaling pathways. However, the relationship between the PSMB9 expression and the occurrence of lower-grade glioma (LGG) is still unknown. First, we collected the RNA-seq and clinical information about LGG clinical samples from The Cancer Genome Atlas (TCGA) cohort, Chinese Glioma Genome Atlas (CGGA; including CGGAseq1 and CGGAseq2) cohort, and Gene Expression Omnibus (GEO; GSE16011, GSE61374, and Rembrandt) cohort. Then, these data were used for differential analysis, survival analysis, enrichment analysis, clinical model construction, etc. In addition, we combine immune-related data for immune-related analysis, including immune infiltration and immunotherapy. Through the above research, we have provided a new biomarker for LGG prognosis prediction and more comprehensively explained the role of PSMB9 in the development of LGG. This study determined that PSMB9 can be used as an immunotherapy target through the analysis of immune data, providing new ideas for the clinical treatment of LGG.

During the service of rotating machinery, the pedestal bolts are prone to looseness due to the vibration environment, which affects the performance of rotating machinery and generate potential safety hazard. To monitor the occurrence and deterioration of the pedestal looseness in time, this paper proposes a data-driven diagnosis strategy for the rotor-bearing system. Firstly, the finite element model of a rotor-bearing system is established, which considers the piecewise nonlinear force caused by pedestal looseness. Taking the vibration response as output and periodic unbalanced force as input, the system’s NARX (Nonlinear Auto-Regressive with exogenous inputs) model is identified. Then GALEs (Generalized Associated Linear Equations) are used to evaluate NOFRFs (Nonlinear Output Frequency Response Functions) of the NARX model. Based on the first three-order NOFRFs, the analytical expression of the second-order optimal weighted contribution rate is derived and used as a new health indicator. The simulation results show that compared with the conventional NOFRFs-based health indicator, the new indicator is more sensitive to weak looseness. Finally, a rotor-bearing test rig was built, and the pedestal looseness was performed. The experiment results show that as the degree of looseness increases, the new indicator SRm shows a monotonous upward trend, increasing from 0.48 in no looseness to 0.90 in severe looseness, a rise of 89.7%. However, the traditional indicator Fe2 has no monotonicity, which further verifies the sensitivity of the first three-order NOFRFs-based second-order optimal weighted contribution rate and the effectiveness of the proposed data-driven feature extraction strategy.

Long service time and excessive vibration of aero-engine will cause failure of clamps, which usually fix pipelines on the outside of an aero-engine. In this paper, the nonlinear vibration characteristics caused by loosening clamps in aero-engine pipeline are determined. According to the real parameters of an aero-engine clamp-pipeline test rig, the clamp is simplified into a nonlinear spring-damping. Thus, a clamp-pipeline nonlinear model based on cubic stiffness is established. The multi-scale method is used to obtain the analytical solution of the nonlinear model. Based on the real test data, the model parameters of the clamp-pipeline nonlinear system are identified, and then the nonlinear vibration characteristics of the system are obtained. Finally, using the vibration transmissibility method, the influence of the severity of clamp loosening on the nonlinear vibration characteristics of the system is obtained.

Based on the Bouc-Wen model, a nonlinear hysteretic restoring force model is established with dynamic equations. The hardening and softening of the material after reaching the yield limit are described by the nonlinear restoring force-displacement hysteretic curve. The Gamultiobj algorithm and the group search optimization (GSO) algorithm are used to fit and identify the material softening and hardening hysteresis curves, respectively. The effectiveness of the optimization algorithm for identifying the parameters of the hysteretic model is verified, and the optimization effects of the two algorithms are compared. The results show that the Gamultiobj algorithm has better parameter identification ability and curve fitting ability for the hysteretic model. Then, the hysteresis curve describing the nonlinear characteristics of a clamp is obtained through the static stiffness experiment of the clamp. The experimental curve is fitted by the Gamultiobj algorithm. As a result, the nonlinear Bouc-Wen model parameters of the clamp are obtained, and the stiffness and damping of the clamp are recognized. The distribution statistics of the obtained parameters are performed, and it is found that each parameter satisfies a certain probability distribution, which indicates that the parameter identification result is reasonable.

The composition and characteristics of the passive film formed in the simulated carbonation solution with the concentration of 1.0% and 2.0% rust inhibitor were studied by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The formation mechanism of steel passive film under the action of rust inhibitor was expounded. The results showed that the anticorrosion performance was the best and stable passive film was formed on the steel surface when the content of rust inhibitor was 2.0%; under the action of rust inhibitor, the main compositions of passive film on the steel surface were Fe2O3 and FeOOH. Among anodic rust inhibitors, Na2MoO4 was more effective than Na2CrO4. Between cathodic rust inhibitors, the anticorrosion performance of benzotriazole (BTA) was better than N-N dimethyl ethanolamine (DMEA). Among the composite rust inhibitors, the corrosion resistance of Na2MoO4 + BTA group was superior, and the corrosion resistance of Na2MoO4 + DMEA group was the worst. The composite rust inhibitor was better than the single rust inhibitor, and the inhibition efficiency was the highest when Na2MoO4 and BTA were mixed together.

Mesoporous materials are eliciting considerable research interest for their application in catalysts and electrodes. In this paper, we report the synthesis of mesoporous α-LiAlO2 via a hydrothermal route using through-hole anodized aluminum oxide (AAO) as templates. Crystal structures and morphologies were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). α-LiAlO2 reproduced the one-dimensional structures of AAO templates and obtained two kinds of nanostructures, namely, nanoparticles and nanoflakes. Extremely high specific surface area of up to 117.3 m²/g and large pore volume of 0.87 cm³/g were confirmed by nitrogen-sorption measurement, which shed light on the potential practical application of mesoporous α-LiAlO2. [ABSTRACT FROM AUTHOR]

Abstract Methane gas plumes have been discovered to issue from the seafloor in the Puget Sound estuary. These gas emission sites are co‐located over traces of three major fault zones that fracture the entire forearc crust of the Cascadia Subduction Zone. Multibeam and single‐beam sonar data from cruises conducted in years 2011, 2018, 2019, 2020, and 2021 identified the acoustic signature of 349 individual bubble plumes. Dissolved CH4 gas from the plumes combines to elevate seawater methane concentrations of the entire Puget Sound estuary. Fluid samples from adjacent terrestrial hot springs and deep‐water wells surrounding the estuary contain a helium‐3 isotope signature, suggesting a deep fluid source located near the underlying Cascadia Subduction Zone plate interface. However, limited data from this pilot study suggest that Puget Sound seawater emission sites lack both similar chemical isotope signatures and elevated thermal anomalies that would be expected from association with a deep plate‐interface reservoir. A shallow reservoir within the Holocene sediments that cover the older Puget Sound basement with horizontal transfer to the thinly covered Alki Point and Kingston Arch anticlines is also a possibility, as has been suggested for other methane seep areas. The existence of vigorous marine methane plumes arising from areas of thin sediment cover associated with deeply penetrating forearc fault zones but presenting no thermal or chemical anomalies found in other similar forearc environments, remains an unresolved paradox.

The abnormal wear of a rolling element bearing caused by early failures, such as pitting and spalling, will deteriorate the running state and reduce the life. This paper demonstrates the importance of oil debris monitoring and its effective feature extraction for bearing health assessment. In this paper, a rolling bearing-rotor test rig with forced lubrication is set up and the nonferrous contaminants with higher hardness were introduced artificially to accelerate the occurrence of pitting and spalling. The early failure and abnormal wear of rolling bearings cannot be effectively detected only through the vibration signal; the temperature and oil debris monitoring data are also collected synchronously. Two features regarding the ferrous particle size distribution are extracted and fused with vibration based-features to form a feature set. The sensitive features are extracted from the features set using the Neighborhood Component Analysis method to avoid feature redundancy. Finally, the importance of the oil debris based-features for the diagnosis of abnormal bearing wear is analyzed with different machine learning algorithms. Taking SVM classifier as an example, the experiment results show that the introduction of oil debris based-features increases the diagnostic accuracy by 15.7%.

Aiming at the bonding performance of the casting interface in the composite ceramsite lightweight aggregate concrete (LWAC) and normal weight concrete (NWC), the experiment on the shear bonding blocks and bending composite beams were designed for progressive study. The Z-shaped composite blocks were first made by the LWAC and NWC with different strength grades considering the variation of the casting interval time and the interface preparing method. The bending composite beams were designed considering the variation of the casting interval time, the relative position between the casting interface and the calculated sectional neutral axis in the LWAC and NWC composite beam. The result indicates that, the bonding shear performance of the casting interface decreases most obviously within 2 days of the casting interval time. The shear strength of the casting interface with 14 days casting interval time for considered different interface preparing methods is higher than that calculated according to the specification. Although there is no bonding sliding failure happening on the casting interface in the composite beam during the experimental loading, a certain influence exists on the crack developing near the casting interface, the load-deflection curve developing, the strain developing of the mid-span section and the subtle damage variation considering the variation of the casting interval time, the relative position between the casting interface and the calculated neutral axis in the composite beam.

The driving mechanism of an axisymmetric vectoring exhaust nozzle (AVEN) is a 3-degrees-of-freedom (3-DOF) parallel manipulator (PM) with a centering device. According to the characteristics of the vectoring nozzle’s movement mechanism, the 3-DOF kinematics model of the 3SPS + 3PRS PM is established. The forward and inverse positional posture models are built based on the mechanism architecture of PM and the closed-loop vector method. The Jacobian matrix and Hessian matrix are derived using screw theory, and velocity and acceleration models are established. Based on the principle of virtual work and combined with the kinematics model of PM, a stiffness model was established to analyze stiffness performance. Finally, the effectiveness of the kinematics model of the PM was verified by a simulation, and the variation of stiffness performances with the positional posture of the PM was quantitatively analyzed. The results show that the translational stiffness decreases with forward axial translation of the moving platform and the rotational stiffness is mainly determined by the posture parameters. This study is expected to offer ideas for the kinematic modeling of 3-DOF PM and provide references for application and optimizing of the AVEN’s driving mechanism.

CuSCN, as a new type of inorganic hole-transporting semiconductor with a wide bandgap (>3.4 eV), is attracting much attention in the fabrication of perovskite solar cells. In this article, by using first-principles density functional theory (DFT) and the quasi-harmonic approximation (QHA) approach, we have studied lattice dynamics and abnormal thermal expansion of the system, including α- and β-CuSCN phases. The influence of the abnormal thermal expansion of the lattice on the electronic structure, especially on the bandgap of the system, was explored and discussed. We found that due to the shearing modes and the three acoustic modes along the direction of the c-axis, the α- and β-CuSCN show a negative thermal expansion (NTE) in the direction of the c-axis. The torsion modes of the Cu–N–C–S atomic chains in the α-CuSCN may lead to an NTE in the directions of the a, b-axes of the α-phase. As a result, our theoretical results demonstrated that the α-CuSCN exhibits an anisotropic bulk NTE. While the β-CuSCN displays a strong uniaxial negative thermal expansion in the direction of the c-axis, in the directions of the a, b-axes, it exhibits positive thermal expansion. Our DFT calculations also predicted that the α-CuSCN has a direct bandgap, which increases slightly with increasing temperature. However, the β-CuSCN has an indirect bandgap at low temperature, which converts to a direct bandgap near the temperature of 375 K due to the strong positive expansion in the ab plane of the phase. Our work revealed the mechanisms of the abnormal thermal expansion of the two phases and a strong coupling between the anisotropic thermal expansion and the electronic structures of the system.

In this paper, a parameter sensitivity analysis of mounting pedestals and a multi-objective optimization design for vibration reduction in a multi-support rigid body system, taking an aeroengine-lubricating oil tank supported by multiple mounting pedestals as an example, are conducted based on the third version of non-dominated sorting genetic algorithm (NSGA-Ⅲ) combined with Sobol’s sensitivity analysis method (SSAM). An aeroengine-lubricating oil tank with three mounting pedestals is simplified as a three-support dynamic system, and its dynamics model is established. Several structural parameters of mounting pedestals are taken as the design variables, and the system vibration response and the reaction force of the front and rear mounting pedestals are considered as the objective functions. The first-order results and total sensitivity index of different design parameters for each objective function are obtained via SSAM, and the five most sensitive parameters are selected. Based on the above five design parameters, multi-objective optimization designing for vibration reduction in a simplified lubricating oil tank system is conducted based on NSGA-Ⅲ, and the results of the above triple-objective optimization are obtained as a Pareto-front surface with an obvious frontier. It can be observed from the simulation results that the oil tank vibration of the optimized system is effectively suppressed under the unbalanced excitation of two typical engine speeds. The established method and the main results can provide guidance for designers of aeroengine external structural systems, which can help to achieve superior system dynamic performances in engineering applications.

This paper analyzed the effects of boundary conditions on the stress distribution of hydraulic support with the static finite element (FE) model. Five loading conditions are considered in this study, including: 1) canopy torsional loading, 2) canopy eccentric loading, 3) base torsional loading, 4) base diagonal loading, and 5) base symmetrical loading. In order to verify the simulation results obtained from the FE model, the corresponding experiments have also been performed. Based on the comparison between simulation and experimental results, the effects of pin-joint simplified methods and boundary conditions are evaluated in terms of accuracy and efficiency. Moreover, the new elastic-support boundary is also proposed to improve the simulation accuracy under conditions 2, 3, 4, and 5. The results show that bonded contact between the pin and shaft hole has high efficiency and accuracy compared with the frictional contact. The frictional contact boundary is reasonable under condition 1. However, the elastic-support boundary is suggested to be adopted to improve calculation accuracy for the stress distribution of the constraint components (canopy or base) under conditions 2, 3, 4, and 5.

Additively manufactured porous NiTi alloys hold unprecedented promise in metallic implants due to their low elastic modulus and superelastic behavior. Such porous structures are usually topologically ordered and designed with periodically-repeating unit cells. However, the superelastic behaviors of fractal porous structures have never been studied. The Menger sponge-like fractal structures consisting of non-periodic fractal pores mimick the architectures and biomechanical properties of human bone. In this investigation, porous NiTi alloys designed with Menger sponges were fabricated by additive manufacturing using selective laser melting technology, and their superelastic behaviors were systematically characterized for the first time. Additively manufactured bulk NiTi alloys exhibit fully recoverable superelastic responses with slim stress hysteresis. The mechanical properties of bulk NiTi alloys match the properties of human cortical bones. The Menger sponges display excellent superelastic recovery strain ratios even at high porosity levels. The mechanical properties of highly fractalized Menger sponges are almost identical to the properties of human cancellous bones. The deformation mechanism undergoes a transformation from bending-dominated to stretching-dominated mode when the porous structures are highly fractalized. The unique combination of fractal topology, nanostructured microstructure, highly controllable elastic modulus and large recoverable deformation make the NiTi Menger sponge a promising candidate for metallic implants.

To solve rebar corrosion in existing concrete structures, two test methods, adding corrosion inhibitors into concrete and applying corrosion inhibitors on the existing concrete surface by brushing and pouring and composite repair, combined with natural potential, XRD and SEM, were used to comprehensively evaluate the performance of nitrite-based compound corrosion inhibitors. The research results show that nitrite has a better inhibitory effect than phosphate, and when the respective mass fraction of hydrogen phosphate and sodium nitrite is about 1.5%, the rust inhibition effect is the optimum. Brushing, perfusion, and composite repair can all play a good role in inhibiting corrosion of which composite repair is the best. The addition of phosphate can improve the macrocell corrosion caused by the low dosage or uneven distribution of nitrite.

In this paper, a pedestal looseness fault model of a rotor-bearing-seal system is established. Under two working conditions of the same direction eccentricity (Working Condition 1) and reverse eccentricity (Working Condition 2), rotor orbits, vibration waveforms, spectrum cascade, and Poincaré maps are used to study the dynamic characteristics of the system when the sliding bearing support is loosened. The influence of speed, the unbalance of two discs, the looseness clearance, and the mass of bearing support on system characteristics are analyzed. The study found that Working Condition 2 is more likely to cause looseness of the bearing support. Moreover, for the rotor system in this paper, the pedestal looseness fault is more likely to occur near the second-order critical speed. Through analysis of the spectrum, it is found that the spectrum of the looseness fault will show multiple frequencies or continuous spectra, and the rotor orbits will appear “cylindrical.”

Background The physical and mental health of college-age youths tends to continuously decline around the world. It is therefore important to promote health during this period. As a traditional Chinese mind-body exercise, Tai Chi Chuan (TCC) may be an available selection. However for the college student population, the evidence is unclear as to whether TCC can be recommended as an effective exercise for promoting their physical and psychological wellbeing. Therefore high quality, rigorous, prospective, and well-controlled randomized trials are needed to further understand TCC serving as a psychological and physical intervention in college age populations. Method/design We designed a randomized, single-blind, parallel-controlled trial with a sample size of 206 participants. All the participants who meet the inclusion criteria come from Fujian University of Traditional Chinese Medicine (FJTCM). Participants of the TCC training group will receive TCC training at a frequency of five days per week for one hour per day for 12 weeks. No specific exercise will be administered on the participants in the control group. Both physical and mental health outcomes, including balance ability, lower limb proprioception, flexibility, physical fitness, self-efficacy, psychological symptoms, attention span, stress, self-esteem, mood and mindfulness, quality of life, and quality of sleep. Safety outcomes will be evaluated by blinded operators at baseline, 12 and 24-weeks post-intervention. Discussion This protocol presents an objective design of a randomized, single-blind trial that will test the effectiveness and safety of TCC on the physical and psychological wellbeing of college students. If the outcome is positive, the results will provide higher quality evidence of TCC on the physical and mental health of college age populations. Trial registration Chinese Clinical Trial Registry: ChiCTR-TRC-13003328. [ABSTRACT FROM AUTHOR]

Background Stroke is a major cause of death and disability in the world, and the prevalence of stroke tends to increase with age. Despite advances in acute care and secondary preventive strategies, primary prevention should play the most significant role in the reduction of the burden of stroke. As an important component of traditional Chinese Qigong, Baduanjin exercise is a simple, safe exercise, especially suitable for older adults. However, current evidence is insufficient to inform the use of Baduanjin exercise in the prevention of stroke. The aim of this trail is to systematically evaluate the prevention effect of Baduanjin exercise on ischemic stroke in the community elder population with high risk factors. Methods A total of 170 eligible participants from the community elder population will be randomly allocated into the Baduanjin exercise group and usual physical activity control group in a 1:1 ratio. Besides usual physical activity, participants in the Baduanjin exercise group will accept a 12-week Baduanjin exercise training with a frequency of five days a week and 40 minutes a day. Primary and secondary outcomes will be measured at baseline, 13 weeks (at end of intervention) and 25 weeks (after additional 12-week follow-up period). Discussion This study will be the randomized trial to evaluate the effectiveness of Baduanjin exercise for primary prevention of stroke in community elder population with high risk factors of stroke. The results of this trial will help to establish the optimal approach for primary prevention of stroke. [ABSTRACT FROM AUTHOR]

By using XRD diffraction patterns and SEM scanning electron microscopy, the study included exploring the effects of carbonation on the types of cations, namely Na+ and Mg2+, on the chloride concentration and mechanism, which is an important factor that has received little attention. The results show that carbonization has a greater negative impact on the binding capacity of chloride ions in cement mixed with NaCl, and CaCl2 can weaken the negative effect of carbonization on the binding capacity of chloride ions and improve the binding capacity of free chloride ion ;During the carbonization of cement mixed with NaCl, the chloride content corresponding to the maximum chloride ion binding rate was reduced from 0.9 % to 0.8 %, while the value was 0.8 % in cement mixed with CaCl2;Carbonization can improve the structure of the cement and reduce the porosity in the cement structure.

Aiming at the bending performance of the prestressed superposing-poured concrete beam, the numerical simulation on the composite beams poured with the normal weight concrete (NWC) superposed on the fibred ceramsite lightweight aggregate concrete (LWAC) was conducted. Three kinds of prestressing schemes, straight linear prestressing force, curved prestressing force not across the casting interface, and curved prestressing force across the casting interface, were simulated for comparison, and the influence of the casting interval time was also considered. Results indicate that the stiffness of the superposing-poured beam can be effectively strengthened by considered schemes of the prestressing force; in addition, there are certain increases on the ultimate load except imposing the straight linear prestressing force. As the curved prestressing force is imposed across the casting interface, the maximal interlayer slip of the casting interfacial transition zone (C-ITZ) approximately equals to that without the prestressing force. The scalar stiffness degradation (SDEG) of the C-ITZ for the casting interval time being 14 days is obvious because of the weakening on the bonding performance of the C-ITZ. Comparatively, the SDEG variation of the C-ITZ in the model with the curved prestressing force across the casting interface is smoother and smaller on the whole than the other two prestressed schemes for the case of the casting interval time being 14 days.

This paper presents the dynamic characteristics analysis of a rigid body system with spatial multi-point elastic supports, as well as the sensitivity analysis of support parameters. A rigid object is characterized by six degrees-of-freedom (DOFs) motions and considering the spatial location vector decomposition of elastic supports, a rigid body system dynamic model with spatial multi-point elastic supports is derived via the Lagrangian energy method. The system modal frequencies are calculated, and to be verified by finite element modal analysis results. Next, based on the above-mentioned model, system modal frequencies are obtained under different support locations, where the support stiffness components are different. Interpolate the stiffness components corresponding to each support location, calculate system modal frequencies, and the response surface model (RSM) for system modal frequencies is established. Further, based on the RSM modal analysis results, the allowable support location for the system modal insensitive area can be obtained. At last, a lubricating oil-tank system with four supports is taken as an example, and the effects of support spatial locations and stiffness components on the system inherent characteristics are discussed. This present work can provide a basis for the dynamic design of the spatial location and stiffness for this type of installation structures.

The output flow pulsation characteristics of the hydraulic pump due to the structural characteristics may cause pump source fluid pressure pulsation and even cause the equipment to vibrate, which will affect the life and working reliability of the equipment. Scholars have done a lot of theoretical and simulation analysis on the characteristics of fluid flow and pressure pulsation caused by the specific structure and structure of the plunger pump, but there are few comparisons and analyses of the simplified model of the plunger pump and the pressure pulsation characteristics with experiments. In this paper, AMESim software is utilized to establish a simplified model of one seven-plunger hydraulic pump, and simulate and analyze the pump source fluid pressure pulsation characteristics of different system load pressures at a constant speed. An experimental platform for testing pump fluid pressure pulsation was designed and built, and the actual measurement and simulation results of pump fluid pressure pulsation were compared and analyzed. The results show that the system simulation data is in good agreement with the measured data, which verifies the correctness of the simplified model of the plunger pump. At the same time, it is found that the fluid pressure pulsation of the pump source exhibits broadband and multi-harmonic characteristics. At a constant speed, as the load pressure of the hydraulic system increases, the pump source fluid pressure pulsation amplitude increases, the pressure pulsation rate decreases, and the impact on the fundamental frequency amplitude is the most significant. The research results can provide a theoretical basis for suppressing the pressure pulsation of the pump source fluid and reducing the vibration response of a hydraulic pipeline under the action of the pulsating harmonic excitation.