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Nanofluids have excellent lubrication and high thermal conductivity. However, the agglomeration and sedimentation produced by the large surface energy of nanoparticles in base liquid threaten the long-term dispersion stability and impact the wide application of nanofluid. In this work, based on the self-assemble behavior and continuous network structure formed by low molecular weight organic gelator, the uniform clusters were formed through regulating the kinetics behavior in the gelling process. The dragging effect was demonstrated by oleic acid - sodium dodecyl sulfate (OA-SDS) bicomponent gelator and graphene oxide (GO) nanosheets. The results showed that GO nanofluids dispersed by OA-SDS were stable for more than 12 months. The well-dispersed GO nanofluid exhibited better anti-friction and anti-wear properties under both immersion and electrostatic minimum quantity lubrication conditions. Moreover, the lower contact angle, surface tension and droplet size of nanofluids after charging improved the wettability on the frictional interface. The GO adsorption film formed on the friction interface protected the tribochemical reaction film of iron oxide and prevented the occurrence of sintering of base oil. [ABSTRACT FROM AUTHOR]

Corrugated damage to bearings is a common fault in electrical facilities such as new energy vehicles, wind power, and high-speed railways. The aim of this article is to reveal the microscopic characteristics and formation mechanism of such damages. The corrugation with alternating "light" and "dark" shape was produced on GCr15 bearing races in the experimental conditions. Compared to the light area, the dark area (in the images generated by optical microscope) has more severe electrical erosion, lower hardness, more concave morphology, and lower oxidation. As the voltage increases, the width of the corrugation, the height difference between corrugation, and surface roughness all increase. It is believed that the formation of corrugated damage requires a sufficiently high voltage to induce the periodic destruction and reconstruction of the lubrication film. When the bearing is in a metal-lubrication film–metal contact state, the high voltage causes the lubrication film to break down and induce electrical erosion. Then, the contact area is in metal–metal contact, and the surface is mainly damaged by mechanical rolling. After the reconstruction of lubrication film, the next round of electrical erosion begins. The results are helpful for a deeper understanding of the mechanism of bearing erosion in electrical application. [ABSTRACT FROM AUTHOR]

Cured epoxy resins have poor abrasion resistance, which shortens the service life of the material. This work aims to improve the tribological properties of epoxy resins by coupling self‐lubrication and auto‐healing. In this study, linseed oil microcapsules with an average particle size of 38.57 μm and good thermal stability were successfully prepared by in situ polymerization. The effects of microcapsule content on the tribological, mechanical, and self‐healing properties of the composite coatings were studied. It was demonstrated that the composite coating has outstanding self‐lubricating properties. The coefficient of friction reduced from 0.634 (pure epoxy resin) to 0.0459 (epoxy resin with 10 wt.% linseed oil microcapsules). Wear rate reduced from 7.16 × 10−4 mm3/(N m) to 1.74 × 10−5 mm3/(N m). The self‐lubricating mechanism of the coating was investigated by SEM and EDS, which indicated that the formation of uniform and continuous lubricating film on the surface of the friction pairs was the key to improving the wear resistance of the material. In addition, the linseed oil released after the microcapsules rupture can repair the abrasion marks by reacting with oxygen during the friction process. The dual‐functional effect of linseed oil microcapsules prolongs the life of epoxy resin coating and expands its application range. [ABSTRACT FROM AUTHOR]

Objective To investigate the levels and clinical significance of serum microRNA (miR)-651 and miR-630 in patients with cervical cancer. Methods From June 2017 to May 2020, 108 cervical cancer patients accepted by our hospital were collected as the cervical cancer group. Meantime, 100 cervical intraepithelial neoplasia (CIN) patients treated in our hospital were regarded as the CIN group, and 110 healthy individuals who underwent physical examination were regarded as the control group. Real-time fluorescence quantitative PCR (qRT-PCR) was applied to detect serum levels of miR-651 and miR-630, while analyzing the relationship between serum miR-651 and miR-630 as well as clinical features and prognosis of patients. Results The serum levels of miR-651 and miR-630 in the cervical cancer group and CIN group were obviously lower than those in the control group (P<0.05), while the serum levels of miR-651 and miR-630 in the cervical cancer group were obviously lower than those in the CIN group (P < 0.05). The expression levels of serum miR-651 and miR-630 were positively correlated (r = 0.542, P < 0.05). The serum levels of miR-651 and miR-630 were related to HPV infection, differentiation, lymph node metastasis, and FIGO staging (P < 0.05). The overall survival rate of patients with low levels of miR-651 and miR-630 was lower than that of patients with high levels. Cox regression analysis showed that, HPV infection, degree of differentiation, lymph node metastasis, FIGO staging, miR-651, and miR-630 were all influencing factors for the prognosis of cervical cancer patients (P < 0.05). Conclusion The serum levels of miR-651 and miR-630 in cervical cancer patients decrease, which are related to HPV infection, differentiation, lymph node metastasis, FIGO staging, and prognosis. [ABSTRACT FROM AUTHOR]

Context The association between free fatty acids (FFAs) and unfavorable clinical outcomes has been reported in the general population. However, evidence in the secondary prevention population is relatively scarce. Objective We aimed to examine the relationship between FFA and cardiovascular risk in patients with coronary artery disease (CAD). Methods This study was based on a multicenter cohort of patients with CAD enrolled from January 2015 to May 2019. The primary outcome was all-cause death. Secondary outcomes included cardiac death and major adverse cardiovascular events (MACE), a composite of death, myocardial infarction, and unplanned revascularization. Results During a follow-up of 2 years, there were 468 (3.0%) all-cause deaths, 335 (2.1%) cardiac deaths, and 1279 (8.1%) MACE. Elevated FFA levels were independently associated with increased risks of all-cause death, cardiac death, and MACE (all P <.05). Moreover, When FFA were combined with an original model derived from the Cox regression, there were significant improvements in discrimination and reclassification for prediction of all-cause death (net reclassification improvement [NRI] 0.245, P <.001; integrated discrimination improvement [IDI] 0.004, P =.004), cardiac death (NRI 0.269, P <.001; IDI 0.003, P =.006), and MACE (NRI 0.268, P <.001; IDI 0.004, P <.001). Notably, when stratified by age, we found that the association between FFA with MACE risk appeared to be stronger in patients aged ≥60 years compared with those aged <60 years. Conclusion In patients with CAD, FFAs are associated with all-cause death, cardiac death, and MACE. Combined evaluation of FFAs with other traditional risk factors could help identify high-risk individuals who may require closer monitoring and aggressive treatment. [ABSTRACT FROM AUTHOR]

This paper is aimed at the problems of abnormal tribological damage and fluctuation of tribological performance in the self-lubricating composite serving in heavy load spherical plain bearing in aerospace field. The Nomex/PTFE fiber reinforced composite was used to carry out a reciprocating block on ring tribological test, investigating the tribological performance of the material and its wear evolution. Results show that the influence of oscillating frequency on material wear is obviously higher than that of load under high load condition (more than 90 MPa or 180 kN). Under a certain load and frequency condition, friction temperature is a key factor to affect wear behavior of the material. Friction heat plays a dominant role in the process of worn out failure of the material. Too high friction temperature greatly weakens the friction and wear performance, resulting in material failure in a short time. Thermal fatigue is the main tribological damage mode of the material under the high load and high frequency condition, with local worn out occurred. This finding was also verified by SEM analysis of the worn surface and wear debris.

In this study, the PTFE/Kevlar self-lubricating composite was prepared for the service conditions of high frequency oscillation. The full-life cycle friction and wear characteristics was analyzed, and the tribological properties and failure mechanism at different life stages were studied. Fatigue life test of PTFE/Kevlar self-lubricating composite was performed by a self-developed heavy load reciprocating test machine. Results show that the self-lubricating performance of the material increases while the wear life decreases with the increase of stress and frequency. The main failure mode of the material consists of abrasive wear and adhesive wear, accompanied by extrusion fracture of the fiber. Tribological performance and surface state show distinct phase characteristics in the life cycle. The change of frequency affects the adhesive wear degree in the fiber fracture area. Differently, the change of stress affects the adhesive wear degree in the fiber fracture area as well as the uniform stability of the transfer film. The comparison of frequency and stress shows that the change of frequency has a greater influence on the material self-lubricating performance and life. This study could provide a research basis for the design and development of self-lubricating composites in high frequency oscillating conditions, and also provide reference data for the calibration of service conditions for PTFE/Kevlar self-lubricating composites.

Mo2BC-TiC composites were fabricated by fast hot-pressing sintering method with Mo2BC powder as raw material and nano-TiC powder as sintering additive. The effect of nano-TiC additive (mass fraction of 5%) on microstructure and tribilogical behavior of Mo2BC composite was investigated. The results show that the addition of nano-TiC significantly improves the sintering properties, microstructure and mechanical properties of Mo2BC ceramic. The relative density, Vickers hardness, flexure strength, compressive strength and fracture toughness of Mo2BC composites are 98.9 %, 18.1 GPa, 480.5 MPa, 2.9 GPa and 4.1 MPa ⋅ m1/2, respectively. Transgranular fracture is the main fracture mode of Mo2BC-TiC composite. Mo2BC-TiC composite also exhibites a good tribological properites with the friction coefficient of 0.42 and wear rate of 0.6 x 10-5 mm³/ (N ⋅ m). [ABSTRACT FROM AUTHOR]

BACKGROUND. Clear cell renal cell carcinoma (ccRCC) is the most common histologically defined renal cancer. However, it is not a uniform disease and includes several genetic subtypes with different prognoses. ccRCC is also characterized by distinctive metabolic reprogramming. Tobacco smoking (TS) is an established risk factor for ccRCC, with unknown effects on tumor pathobiology. METHODS. We investigated the landscape of ccRCCs and paired normal kidney tissues using integrated transcriptomic, metabolomic, and metallomic approaches in a cohort of white males who were long-term current smokers (LTS) or were never smokers (NS). RESULTS. All 3 Omics domains consistently identified a distinct metabolic subtype of ccRCCs in LTS, characterized by activation of oxidative phosphorylation (OXPHOS) coupled with reprogramming of the malate-aspartate shuttle and metabolism of aspartate, glutamate, glutamine, and histidine. Cadmium, copper, and inorganic arsenic accumulated in LTS tumors, showing redistribution among intracellular pools, including relocation of copper into the cytochrome c oxidase complex. A gene expression signature based on the LTS metabolic subtype provided prognostic stratification of The Cancer Genome Atlas ccRCC tumors that was independent of genomic alterations. CONCLUSION. The work identified the TS-related metabolic subtype of ccRCC with vulnerabilities that can be exploited for precision medicine approaches targeting metabolic pathways. The results provided rationale for the development of metabolic biomarkers with diagnostic and prognostic applications using evaluation of OXPHOS status. The metallomic analysis revealed the role of disrupted metal homeostasis in ccRCC, highlighting the importance of studying effects of metals from e- cigarettes and environmental exposures. FUNDING. Department of Defense, Veteran Administration, NIH, ACS, and University of Cincinnati Cancer Institute., Introduction Clear cell renal cell carcinoma (ccRCC) is characterized by loss of tumor suppressors localized to the short arm of chromosome 3, including the von Hippel Lindau gene (VHL), which [...]

Lubricant additive plays an important role in reducing the friction and wear for base oil. MAX phase ceramics may have superior advantages for additive application due to their unique nanolayered structure. In this paper, Ti2SnC ceramic is prepared by sintering the elemental mixtures at 1250 °C. In addition, Cu-coated Ti2SnC ceramic is successfully prepared using a chemical plating method for the first time. It is confirmed that the Ti2SnC ceramic has good self-catalytic activity, and a layer of stacking Cu nano-particles can be deposited on the Ti2SnC surface without pretreatment. When the Cu-coated Ti2SnC ceramic powder is doped into PAO10 base oil, the oil can exhibit excellent lubrication properties, where the friction coefficient is as low as 0.095. A layer of tribo-film can be formed during the sliding process when the Cu-coated Ti2SnC ceramic is incorporated into PAO10 base oil, which can reduce the friction coefficient. The superior lubrication properties can be attributed to the synergistic lubrication effect of Ti2SnC ceramic and Cu nano-particles. [ABSTRACT FROM AUTHOR]