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Due to the excellent properties of titanium alloys, they are widely used in various fields. However, the poor tribological performance limits the further development of titanium alloys. In this paper, TC4 with microporous channels was manufactured by laser additive manufacturing technology. On this basis, TC4-Sn-Ag-Cu (TSAC) and TC4-Sn-Ag-Cu-Nb2C (TSACN) self-lubricating materials were prepared. The friction and wear tests were carried out under dry friction conditions, and tribological behaviors and friction-induced noise were analyzed. The results show that TSACN self-lubricating composite has outstanding tribological properties and noise suppression performance. Compared with TC4, the friction coefficient and equivalent sound pressure level of TSACN are reduced by 20.1 and 6.7%, respectively. The excellent tribological properties are mainly attributed to the synergistic effect of microporous channel and Sn-Ag-Cu-Nb2C. Microporous channel can promote the diffusing of lubricants and accelerate the formation rate of lubricating film; Nb2C can enhance soft metal lubricant Sn-Ag-Cu to make the lubricating film more dense. The lubricating film can repair wear pits, furrows and other defects on the worn surface and avoid the direct contact between the counterpart ball and the sample, thereby improving the tribological properties of TC4 and reducing the friction-induced vibration and noise. [ABSTRACT FROM AUTHOR]

Inspired by rhombic textures on shark skin surface, this paper designs bionic micro-textures filled by solid lubricants SnAgCu and Ti3C2TX to improve the tribological properties of 42CrMo steel. Compared with 42CrMo steel, the average friction coefficient and wear depth of 42CrMo-SnAgCu-Ti3C2TX with bionic micro-textures at 25 N were separately decreased by 41.52 and 79.07%, and decreased by 50.77 and 80% at 35 N, respectively. Two-dimensional material Ti3C2TX can be well combined with SnAgCu to promote the formation of a smooth and continuous lubricating film on the worn surface, which plays an excellent antifriction and wear resistance role under the specific working conditions. [ABSTRACT FROM AUTHOR]

Introduction: The progression of placental diseases such as preeclampsia is closely related to trophoblast dysfunction. Recent studies indicated the dysregulation of N6-methyladenosine (m6A) RNA modification in trophoblast disorders, while the function of METTL3, a methyltransferase of m6A, in trophoblasts remains to be studied.Methods: The expression of METTL3 was determined by real-time PCR and immunoblotting. METTL3 expression in trophoblast cell lines HTR-8/SVneo and JEG-3 was knocked down using shRNA. The invasion of trophoblast cells in Matrigel was determined using xCELLigence. The m6A-containing transcripts was determined by m6A-sequencing in HTR-8/SVneo cells. The myosin light chain kinase (MYLK) gene was transfected into HTR-8/SVneo cells.Results: The expression of METTL3 was downregulated in preeclamptic placentae compared to normal placentae. Knockdown of METTL3 repressed the invasion of extravillous trophoblast cells. Mechanistically, METTL3 promoted the stability of MYLK mRNA through m6A modification. Overexpression of MYLK rescued retarded cell invasion by METTL3 depletion.Discussion: Collectively, our results highlight an essential role of METTL3-MYLK axis in trophoblast invasion. [ABSTRACT FROM AUTHOR]

To improve the tribo-performance of molybdenum disulphide lithium grease (MDLG), the tribological behaviors of 42CrMo under grease lubrication with Ti3C2 as an additive were systematically studied. The results show that when the concentration of MXenes-Ti3C2 in MDLG is 2 wt.%, the friction coefficient and wear volume loss could be respectively reduced by a maximum of 69 and 98%. This is mainly attributed to the graphitization of MXenes-Ti3C2 induced by the friction. It retards the breakage of soap fibers and in turn significantly improves the tribological performance of MDLG under the low speed and high load conditions. In order to predict better working conditions for obtaining the excellent tribological behavior, the experimental results were used to develop a Genetic Algorithm-Artificial Neural Network (GA-ANN) model. Under the predicted working conditions, the estimated friction coefficient (R2 = 0.993) and wear volume loss (R2 = 0.934) were close to the experimental results. This study could provide the support for the application of MXenes-Ti3C2 as an additive in the lubrication grease. [ABSTRACT FROM AUTHOR]

To improve the tribological performance of CSS-42L bearing steel, smooth surfaces (SSs), groove-textured surfaces (GSs), GSs with Sn-Ag-Cu (GSs-SAC), and GSs with Sn-Ag-Cu-Ti3C2 (GSs-SACT) were prepared on CSS-42L. In addition, experimental studies were conducted on tribological properties. The obtained results indicated that GSs-SACT exhibited the best anti-friction and noise reduction performances. These remarkable tribological performances were attributed to the synergistic effects of grooves, Sn-Ag-Cu, and MXene-Ti3C2. The inconsistent rules of frictional forces were improved by the grooves and SACT, which inhibit the friction-induced noise. The micro-nano size-effects of MXene-Ti3C2 enhanced the repairing effect and anti-friction property of composite lubricants, which improved the profile characteristics of GSs-SACT. [ABSTRACT FROM AUTHOR]

In order to further understand the role of MXene-Ti3C2 in oil–solid synergistic lubrication, three kinds of microporous channel composites, M50, M50-Sn-Ag-Cu and M50-Sn-Ag-Cu-Ti3C2, were designed and prepared in this study. Tribological behaviors under different environmental conditions of oil lubrication and dry friction were analyzed. The results show that M50-Sn-Ag-Cu-Ti3C2 exhibits excellent tribological properties under oil lubrication. Mxene-Ti3C2 enhances the strength of solid lubricant film, so that the oil film can give full play to the antifriction and wear resistance of solid lubricant film. The synergistic effect of lubricating oil, solid lubricants and bionic curved microchannel reduces the friction coefficient and wear rate. The vibration acceleration along the reciprocating direction is also reduced. [ABSTRACT FROM AUTHOR]