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• The in-depth mechanism of β texture intensity affecting fretting wear resistance was revealed. • The samples with moderate rolling-texture intensity exhibit serious fretting wear. • The samples with a very high or low rolling-texture intensity exhibit excellent wear resistance. • The unique orientation-layered structure (OLS) enables dislocations to migrate and combine, leading to strong recovery ability and high crack damage resistance. Fretting damage is common in the high-strength titanium alloy fastener widely used in the aeronautic industry, leading to the failure of fastening fit or the initiation of crack. The titanium alloy fasteners often have typical preferred orientation characteristics (i.e., texture), and this is one of the important factors affecting its performance. However, the investigations on the mechanism of β rolling-texture intensity on fretting damage resistance and subsurface deformation are less addressed. Hence, fretting wear tests were carried out on samples with different rolling texture intensities. The results demonstrate that the samples with quite low (A-10 % sample) and quite high (D-70 % sample) rolling-texture intensity both exhibit excellent fretting wear resistance, but their mechanisms are completely different. Uniformly dispersed grain orientation renders the A-10 % sample with good recovery ability and a positive friction effect during wear. Low stress only concentrating at grain boundaries (GBs) weakens cracks' initiation and propagation. The unique orientation-layered structure (OLS) leads to excellent recovery ability and a positive friction effect. Crack propagation is inhibited and only propagates along the OLS boundary without a connected trend. However, samples with moderate rolling texture intensity exhibit severe wear. Dislocations are restricted in local areas, so the poor recovery ability makes them have a negative friction effect. Crack propagation driving force continuously increases. Appropriate rolling texture intensity can reduce wear by three times. This study can provide information on the principle for designing fretting damage-resistant alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

Fretting wear damage of high-strength titanium fasteners has caused a large number of disastrous accidents. Traditionally, it is believed that both high strength and excellent ductility can reduce fretting wear damage. However, whether strength and ductility are contradictory or not and their appropriate matching strategy under the external applied normal stress (Fw) are still confusing problems. Here, by analyzing the subsurface-microstructure deformation mechanism of several samples containing various αprecipitate features, for the first time, we design strategies to improve fretting damage resistance under different matching relation between Fwand the tensile strength of materials (Rm). It is found that when Fwis greater than Rmor Fwis nearly equivalent to Rm, the deformation mechanism mainly manifests as serious grain fragmentation of βand αGBconstituents. Homogeneous deformation in large areas only reduces damage to a limited extent. It is crucial to improve the strength to resist cracking and wear, but it is of little significance to improve the ductility. However, when Fwis far less than Rm, coordinated deformation ability reflected by ductility plays a more important role. The deformation mechanism mainly manifests as localized deformation of βand αGBconstituents (kinking induced by twinning and spheroidizing). A unique composite structure of nano-grained/lamellar layer and localized deformation transition layer reduces fretting damage by five times compared with a single nano-grained layer. Only when the strength is great enough, improving the plasticity can reduce wear. This study can provide a principle for designing fretting damage resistant alloys.

Fretting damage is a key factor restricting the reliability and long life of high-strength titanium alloy fasteners. The fretting damage mechanisms correlated by the interplay relationship between wear damage and surface fatigue damage still need to be addressed. In the present work, fretting damage mechanisms of a high-strength titanium alloy (Ti-15Mo-2.7Nb-3Al-0.25Si, in wt %) were studied in depth. To represent the different matches of strength and toughness, three microstructures with different volume fractions of the primary α phase (A-20%, B-10%, C-1%) were applied to fretting wear tests. The evolution process of fretting wear effected by different microstructures is simulated and quantitatively combined with the sectional inclined angle of scars and the antiwear velocity of wear debris. The results demonstrate that the final worn volume of B-10% is the greatest and the best fretting wear resistance is achieved in A-20%. For wear damage, due to both the poor protective effect of the tribolayer and the fact that the tribolayer is hard to compact, B-10% has the highest wear velocity. For surface fatigue damage, the slip ratio was calculated and used as a bridge to correlate and predict wear damage and fatigue damage. The microcrack damage is most severe in C-1% but slight in A-20%. This study provides valuable experimental data for the prediction of fatigue life for fretting of titanium fasteners, and the quantitative analysis method could be generalized to other alloys.

Signaling pathway alterations in COVID-19 of living humans as well as therapeutic targets of the host proteins are not clear. We analyzed 317 urine proteomes, including 86 COVID-19, 55 pneumonia and 176 healthy controls, and identified specific RNA virus detector protein DDX58/RIG-I only in COVID-19 samples. Comparison of the COVID-19 urinary proteomes with controls revealed major pathway alterations in immunity, metabolism and protein localization. Biomarkers that may stratify severe symptoms from moderate ones suggested that macrophage induced inflammation and thrombolysis may play a critical role in worsening the disease. Hyper activation of the TCA cycle is evident and a macrophage enriched enzyme CLYBL is up regulated in COVID-19 patients. As CLYBL converts the immune modulatory TCA cycle metabolite itaconate through the citramalyl-CoA intermediate to acetyl-CoA, an increase in CLYBL may lead to the depletion of itaconate, limiting its anti-inflammatory function. These observations suggest that supplementation of itaconate and inhibition of CLYBL are possible therapeutic options for treating COVID-19, opening an avenue of modulating host defense as a means of combating SARS-CoV-2 viruses.

The lubrication effectiveness of MoS2nanoparticles as an oil additive remains unclear, restricting its application in industry to reduce friction. The goal of this work was to explore the lubrication mechanism of MoS2nanoparticles as an oil additive. In this study, the oil film thickness behaviors of MoS2nanoparticles in poly-alpha olefin (PAO4) base oil, PAO4 with 3 wt% dispersant (polyisobutyleneamine succinimide, PIBS), and 0W20 engine oil were investigated using an elastohydrodynamic lubrication (EHL) testing machine. Following the EHL tests, the flow patterns around the contact area and the tribofilm covering rate on contact area were studied using optical microscopy to understand the lubrication mechanism. The results indicate that both the dispersant and nanoparticle aggregation significantly affected the oil film thickness. The expected oil film thickness increase in the case of 0.1 wt% MoS2in PAO4 base oil was obtained, with an increase from 30 to 60 nm over 15 min at a velocity of 50 mm/s. Flow pattern analysis revealed the formation of particle aggregation on the rolling path when lubricated with 0.1 wt% MoS2, which is associated with a tribofilm coverage rate of 41.5% on the contact area. However, an oil film thickness increase and particle aggregation were not observed during the tests with 0.1 wt% MoS2blended with 3 wt% PIBS as the dispersant in PAO4 base oil, and for 0.75 wt% MoS2in 0W20 engine oil. The results suggest that nanoparticles responsible for tribofilm formation originated from aggregates, but not the well-dispersed nanoparticles in point contact. This understanding should aid the advancement of novel lubricant additive design.

Minimizing friction and wear at a rubbing interface continues to be a challenge and has resulted in the recent surge toward the use of coatings such as diamond-like carbon (DLC) on machine components. The problem with the coating approach is the limitation of coating wear life. Here, we report a lubrication approach in which lubricious, wear-protective carbon-containing tribofilms can be self-generated and replenishable, without any surface pretreatment. Such carbon-containing films were formed under modest sliding conditions in a lubricant consisting of cyclopropanecarboxylic acid as an additive dissolved in polyalphaolefin base oil. These tribofilms show the same Raman D and G signatures that have been interpreted to be due to the presence of graphite- or DLC films. Our experimental measurements and reactive molecular dynamics simulations demonstrate that these tribofilms are in fact high-molecular weight hydrocarbons acting as a solid lubricant.

Loss of TGF-ß tumour suppressive response is a hallmark of human cancers. As a central player in TGF-ß signal transduction, SMAD4 (also known as DPC4) is frequently mutated or deleted in gastrointestinal and pancreatic cancer. However, such genetic alterations are rare in most cancer types and the underlying mechanism for TGF-ß resistance is not understood. Here we describe a mechanism of TGF-ß resistance in ALK-positive tumours, including lymphoma, lung cancer and neuroblastoma. We demonstrate that, in ALK-positive tumours, ALK directly phosphorylates SMAD4 at Tyr?95. Phosphorylated SMAD4 is unable to bind to DNA and fails to elicit TGF-ß gene responses and tumour suppressing responses. Chemical or genetic interference of the oncogenic ALK restores TGF-ß responses in ALK-positive tumour cells. These findings reveal that SMAD4 is tyrosine-phosphorylated by an oncogenic tyrosine kinase during tumorigenesis. This suggests a mechanism by which SMAD4 is inactivated in cancers and provides guidance for targeted therapies in ALK-positive cancers.

Transverse-flux with high efficiency has been applied in Stirling engine and permanent magnet synchronous linear generator system, however it is restricted for large application because of low and complex process. A novel type of cylindrical, non-overlapping, transverse-flux, and permanent-magnet linear motor(TFPLM) is investigated, furthermore, a high power factor and less process complexity structure research is developed. The impact of magnetic leakage factor on power factor is discussed, by using the Finite Element Analysis(FEA) model of stirling engine and TFPLM, an optimization method for electro-magnetic design of TFPLM is proposed based on magnetic leakage factor. The relation between power factor and structure parameter is investigated, and a structure parameter optimization method is proposed taking power factor maximum as a goal. At last, the test bench is founded, starting experimental and generating experimental are performed, and a good agreement of simulation and experimental is achieved. The power factor is improved and the process complexity is decreased. This research provides the instruction to design high-power factor permanent-magnet linear generator.

Tunable all-optical plasmonic diode is proposed based on the Fano resonance in an asymmetric and nonlinear system, comprising metal–insulator–metal waveguides coupled with nanocavities. The spatial asymmetry of the system gives rise to the nonreciprocity of the field localizations at the nonlinear gap between the coupled cavities and to the nonreciprocal nonlinear response. Nonlinear Fano resonance, originating from the interference between the discrete cavity mode and the continuum traveling mode, is observed and effectively tuned by changing the input power. By combining the unidirectional nonlinear response with the steep dispersion of the Fano asymmetric line shape, a transmission contrast ratio up to 41.46 dB can be achieved between forward and backward transmission. Our all-optical plasmonic diode with compact structure can find important applications in integrated optical nanocircuits.

Five new tridentate ligands and their corresponding La(III) complexes, [La(III)(L)2(H2O)n](ClO4)3where n= 2,3 and 4; L is N-methyl-1,10-phenanthroline-2-methyleneamine (L1), N-ethyl-1,10-phenanthroline-2-methyleneamine (L2), N-propyl-1,10-phenanthroline-2-methyleneamine (L3), N-n-butyl-1,10-Phenanthroline-2-methyleneamine (L4), and N-benzyl-1,10-phenanthroline-2-methyleneamine (L5), have been synthesized, and characterized by elemental analysis, IR, far-IR, 1H-NMR, thermal gravity analysis and conductance measurement. The interaction of the lanthanum(III) complexes with calf thymus DNA was studied by means of UV, fluorescence, CD and viscosity measurements. Using ethidium bromide as a fluorescence probe, the binding mode of the complexes with calf thymus DNA was studied spectroscopically. All the results suggest that the complexes perhaps interact with calf thymus DNA by intercalative and coordination binding mode.Five new tridentate ligands and their corresponding La(III) complexes, [La(III)(L)2(H2O)n](ClO4)3where n= 2,3 and 4; L is N-methyl-1,10-phenanthroline-2-methyleneamine (L1), N-ethyl-1,10-phenanthroline-2-methyleneamine (L2), N-propyl-1,10-phenanthroline-2-methyleneamine (L3), N-n-butyl-1,10-Phenanthroline-2-methyleneamine (L4), and N-benzyl-1,10-phenanthroline-2-methyleneamine (L5), have been synthesized, and characterized by elemental analysis, IR, far-IR, 1H-NMR, thermal gravity analysis and conductance measurement. The interaction of the lanthanum(III) complexes with calf thymus DNA was studied by means of UV, fluorescence, CD and viscosity measurements. Using ethidium bromide as a fluorescence probe, the binding mode of the complexes with calf thymus DNA was studied spectroscopically. All the results suggest that the complexes perhaps interact with calf thymus DNA by intercalative and coordination binding mode.

A Correction to this paper has been published: https://doi.org/10.1038/s41556-021-00638-5.

The optimum parameters for laser propulsion are discussed, such as laser induced pressure on targets, interaction parameters (C_(m), I_(sp)) and optimum laser intensity I_(s), etc. It is verified that the larger laser power density will induce higher thrusting force. It is also found that, to drive a 1.010-kg target during confined laser ablation in vacuum and a 17.45-g one during direct laser ablation in air at the standard pressure, the needed minimum power intensities are on the same order of magnitude.