This study presents detailed experimental investigations on precision machining of the TiAl-based alloy with an abrasive belt flexible grinding method. Subsequently, the feasibility of this precision ...machining method is evaluated with respect to the material removal rate, abrasive wear, machined surface roughness, and residual stress. The material removal rate and surface roughness were determined as experimental indicators and were measured via a three-coordinate measuring instrument and surface profiler, respectively. Micro-morphologies of the machined surface and worn abrasive belt were investigated via a scanning electron microscope. The residual stress distributions in the machined surface layer were detected by using an X-ray diffractometer. The experimental results revealed that the aforementioned evaluation indicators satisfied the desired requirements, thereby indicating that the abrasive belt flexible grinding technique was suitable for precision machining of the TiAl-based alloy. Additionally, the optimal combinations of grinding parameters were determined to obtain desirable material removal rate and machined surface roughness. The basic wear processes and characteristics of the abrasive belt were thoroughly examined. The formation of desirable residual compressive stresses in the machined surface layer was mainly attributed to low frequency and small amplitude vibration knocking at the grinding interface.
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•±45° crossed groove is designed to improve CFRTP/TC4 joint strength by 120.1%•Enhanced chemical bonding TiOS was first observed at the CFRTP/TC4 joint interface.•Rising contact ...thermal resistance & mechanical interlocking improve joint strength.
Laser surface treatment can enhance the joint strength of reinforced thermoplastic composites (CFRTP) and metal joints. In this study, an ultraviolet picosecond laser system grooved the Ti-6Al-4V (TC4) surface, and the influence of grooves on the CFRTP/TC4 joints was investigated. 0° parallel, 90° parallel, 45° parallel, 0/90° crossed and ±45° crossed grooves were created on TC4 surface. Compared with the joint without grooves, the joint strength was improved by all groove patterns. The grooves improve the thermal contact resistance at the interface, and buffer the energy input of the CFRTP side, inhibiting the pyrolysis of the CFRTP and eliminating the bubble defects. Meanwhile, the groove enhances mechanical interlocking. The joint with ±45° crossed grooves was the strongest, being 120.1% stronger than the joint without grooves (ultimate shear force of 1552N). Apart from the mechanical interlocking, the compound layer consisting of the CTi0.42V1.58 phase was confirmed and a novel chemical bonding, TiOS, was also discovered at the interface. However, no significant effect of the grooves on chemical bonding was found. The increase in thermal contact resistance and the mechanical interlocking reinforcement after cooling were the main strengthening mechanisms of the grooves.
Background: Acute lung injury (ALI) is a type of severe pulmonary inflammatory disease with high rates of morbidity and mortality. Now, an increasing number of studies suggest that lncRNAs may act as ...key regulators of the inflammatory response and play a crucial role in the pathogenesis of many inflammatory diseases. Our study firstly explored the function and underlying mechanism of lncRNA metastasis-associated lung adenocarcinoma transcription 1 (MALAT1) in regulating the inflammatory response of lipopolysaccharide (LPS)-induced ALI in rats. Methods: The ALI rats were constructed by intratracheal instillation with LPS. Hematoxylin and eosin (HE) for histological examination were performed to detect histopathological changes in the lung tissues. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentrations of cytokines TNF-α, IL-6, and IL-1β in the supernatants of the bronchoalveolar lavage fluid (BALF). Quantitative real-time PCR (qRT-PCR) analysis was employed to assess the expression of MALAT1, miR-146a, TNF-α, IL-6, and IL-1β in lung tissues. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were used to detect the relationship between MALAT1 and miR-146a. Results: The results revealed that MALAT1 knockdown played a protective role in the LPS-induced ALI rat model. In addition, knockdown of MALAT1 in vitro inhibited LPS-induced inflammatory response in murine alveolar macrophages cell line MH-S and murine alveolar epithelial cell line MLE-12. This study found that MALAT1 acts as a molecular sponge for miR-146a and MALAT1 negatively regulated miR-146a expression. Mechanistically, MALAT1 overexpression alleviated the inhibitory effect of miR-146a on LPS-induced inflammatory response in MH-S. Conclusions: Together, our study provided the first evidence that MALAT1 knockdown could suppress inflammatory response by up-regulating miR-146a in LPS-induced ALI, which provided a potential therapeutic target for the treatment of ALI.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Compared with the PNS standard sensor, the cilia sensor can perform two-dimensional turbulence observation.•Streamlined package design can enhance the effect of flow diversion.•The sensitivity of ...the lollipop-shaped cilia sensor is almost 50 times more than that of the PNS sensor.
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A lollipop-shaped cilia sensor based on the MEMS vector hydrophone was designed for measuring ocean turbulence. The micro-cross beam structure met successfully detected the ocean turbulence vector. In addition, the cilia were designed in a lollipop shape, which not only increased the turbulence signal receiving area but also achieved better diversion effects. In general, the turbulence signal is usually concentrated in the range 0–200 Hz. The sensor structure was simulated and analyzed and its size was optimized. The frequency response bandwidth was also ensured, leading to improved sensitivity. The results of sensor calibration experiments prove that the lollipop-type cilia sensor has high sensitivity, reaching 2.73×10−2 Vms2/kg. In addition, the vector test results verify that the MEMS turbulence sensor accurately measured the two-dimensional ocean turbulence.
Ultrasound based methods can assess muscle fatigue by penetrating deep muscles and are not susceptible to electrical noise, but traditional ultrasound probes have bulky size that hinders integration ...and wearability, making them impractical to continuously monitor muscle status. This paper proposed a wearable probe based on piezoelectric micromachined ultrasonic transducers (PMUTs), where a polymer acoustic lens was incorporated to focus ultrasonic beam and enhance the emitted acoustic pressure (increased by >20%). The fatigue dynamics of upper arm muscles during sustained exertion was investigated by continuously monitoring thickness changes with the PMUTs-based probe, revealing a temporal pattern characterized by swift and subsequent gradual thickening. Several muscle fatigue metrics were derived by piecewise linear fitting, including the initial and secondary deformation rate and the transition time, offering insight into muscle status and fatigue resistance. Additionally, an outlier elimination method for thickness profiles was utilized, mitigating the influence of uncontrollable motion on findings. Leveraging PMUTs technology and acoustic lens integration, this proposed wearable approach holds promise for real-time assessment of muscle fatigue.
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•A compact, cost-effective PMUT-based wearable probe was fabricated to continuously monitor muscle fatigue.•Polymer acoustic Lens was incorporated to focus and enhance the emitted acoustic pressure (increased by >20%).•An outlier elimination technique for thickness profiles was introduced to mitigate uncontrollable motions' impact.•Fatigue metrics were derived to characterize muscle fatigue resistance or indicate fatigue onset.
Abstract
That a mobile welding robot with an adaptive seam tracking ability can greatly improve welding efficiency and quality has been extensively studied. To further improve automation in ...multiple-station welding, we developed a novel intelligent mobile welding robot consisting of a four-wheeled mobile platform and a collaborative manipulator. With the support of simultaneous localization and mapping (SLAM) technology, the robot is capable of automatically navigating to different stations to perform welding operations. To automatically detect the welding seam, a composite sensor system including an RGB-D camera and a laser vision sensor is creatively applied. Based on the sensor system, a multi-layer sensing strategy is performed to ensure that the welding seam can be detected and tracked with high precision. By applying a hybrid filter to the RGB-D camera measurement, the initial welding seam could be effectively extracted. Next, a novel welding start point detection method is proposed. Meanwhile, to guarantee the tracking quality, a robust welding seam tracking algorithm based on laser vision sensor is presented, to eliminate the tracking discrepancy caused by the platform parking error, through which the tracking trajectory can be corrected in real-time. The experimental results show that the robot can autonomously detect and track the welding seam effectively at different welding stations. Also, multiple-station welding efficiency can be improved and quality can also be guaranteed.
Puffing, auto-ignition and combustion characteristics of an n-pentanol-diesel droplet are investigated using the droplet suspension technology under ambient temperatures of 830–930 K and n-pentanol ...concentrations of 0%–75%. The evolution profile of OH∗ chemiluminiscence is detected by a monochromator. A spike is observed shortly after the auto-ignition time for all these profiles. After the spike, different n-pentanol concentrations lead to different evolution profiles of OH∗ intensity. The profile of D75P25 (75% diesel and 25% n-pentanol by mass) witnesses a slight increase and enters a plateau stage. For D25P75, the combustion and extinguishment of n-pentanol vapor lead to the increase and decrease of OH∗ intensity in a long period, respectively. Furthermore, two auto-ignition delays are obtained by a high-speed camera and a monochromator. The difference between the two auto-ignition delays is nearly irrelevant to n-pentanol concentration at 880 K, while a positive dependence on n-pentanol concentration is shown at 930 K. On the other hand, the higher n-pentanol concentration leads to a longer auto-ignition delay at 880 K but a shorter auto-ignition delay at 930 K. Surface and inner puffing modes are observed at 930 K for D25P75 and D75P25, respectively. Many factors lead to different turning phenomena in droplet temperature curves.
•The evolution of OH∗ chemiluminiscence is detected by a monochromator with a collimator.•The auto-ignition delays are measured by a camera and a monochromator.•The higher n-pentanol concentration leads to a longer auto-ignition delay at 880 K.•The higher n-pentanol concentration leads to a shorter auto-ignition delay at 930 K.•D75P25 and D25P75 show different variations in the OH∗ intensity after the auto-ignition.
The heterogeneity of diffuse large B-cell lymphoma (DLBCL) acts as a main barrier to identify the genetic basis of the disease and the choice of treatment. Differentially expressed genes (DEGs) from ...three mRNA expression profile datasets were screened using GEO2R, and bioinformatics analysis was performed on the DEGs. A total of six upregulated and 13 downregulated DEGs were identified. Among these, two hub genes with a high degree of correlation were selected. FBN1 and TIMP1 were identified via STRING analysis and validated by GEPIA. FBN1 and TIMP1 were highly expressed in DLBCL tissues. FBN1 expression was significantly higher in patients of the Ann Arbor stage group (III-IV), with higher IPI score (3-5), and in the non-GCB group. Patients with high TIMP1 expression were more frequently associated with B symptoms, Ann Arbor stage (III-IV), higher IPI score (3-5) and were in the non-GCB group. Furthermore, FBN1 siRNA decreased FBN1 and TIMP1 expression and downregulation of TIMP1 attenuated TIMP1 expression but not of FBN1. Migration of DLBCL cells reduced when treated with either FBN1 or TIMP1 siRNA. Moreover, FBN1 or TIMP1 siRNA decreased the expression of Wnt target genes. Simultaneous overexpression of TIMP1 resulted in an increase in these proteins. This confirmed that both FBN1 and TIMP1 were positively associated with DLBCL progression. Further analysis revealed that FBN1/TIMP1 interaction could improve DLBCL cell migration and regulate the Wnt signaling pathway. Although the underlying mechanisms regarding the interaction between FBN1 and TIMP1 requires further clarification, they might be potential therapeutic targets for DLBCL therapy.
