Chronic heart failure (CHF) is the final outcome of many cardiovascular diseases, and is a severe health issue faced by the elderly population. Mixed lineage kinase 3 (MLK3), a member of MAP3K ...family, is associated with aging, inflammation, oxidative stress, and related diseases, such as CHF. MLK3 has also been reported to play an important role in protecting against cardiomyocyte injury; however, its function in myocardial fibrosis is unknown. To investigate the role of MLK3 in myocardial fibrosis, we inhibited the expression of MLK3, and examined cardiac function and remodeling in TAC mice. In addition, we assessed the expression of MLK3 protein in ventricular cells and its downstream associated protein. We found that MLK3 mainly regulates NF-κB/NLRP3 signaling pathway-mediated inflammation and that pyroptosis causes myocardial fibrosis in the early stages of CHF. Similarly, MLK3 mainly regulates the JNK/p53 signaling pathway-mediated oxidative stress and that ferroptosis causes myocardial fibrosis in the advanced stages of CHF. We also found that promoting the expression of miR-351 can inhibit the expression of MLK3, and significantly improve cardiac function in mice subjected to TAC. These results suggest the pyroptosis and ferroptosis induced by MLK3 signaling in cardiomyocytes are essential for adverse myocardial fibrosis, in response to pressure overload. Furthermore, miR-351, which has a protective effect on ventricular remodeling in heart failure caused by pressure overload, may be a key target for the regulation of MLK3.
Nonequilibrium molecular dynamics (NEMD) simulations were performed to investigate the tribology behaviors of Al
2
O
3
and MoS
2
nanoparticles confined between iron (Fe) slabs. Results indicated that ...the combined use of these two nanoparticles yielded the lowest and most stable friction force, normal force, interface temperature and wear rate, which exhibited a significant synergistic lubrication effect. A novel parameter the rolling/sliding motion coefficient (
K
rs
) was proposed to evaluate the motion pattern of spherical Al
2
O
3
. There were 51% rolling + 49% sliding motion when used alone and 91% rolling + 9% sliding in the existence of MoS
2
. Similarly, about 72.3% of the friction was shared by interlayer sliding of MoS
2
monolayers in the presence of Al
2
O
3
, which was higher than used alone (54.8%). Then, the diffusion of atoms at the friction interface was explored to reveal the synergistic lubrication mechanism. The tribofilm formed by the diffusion of Fe and S atoms could protect the metal surfaces from further wear. The adsorption of S atoms to Al
2
O
3
nanoparticle could promote its rolling effect and prevent it from embedding into iron matrix. Besides, Al
2
O
3
could also facilitate the separation of MoS
2
monolayers to enhance their interlayer sliding effect.
The water-based MoS2 nano-lubricant was prepared and tentatively applied in cold rolling lubricant recirculation systems to investigate its recycling prospect and sustainable lubrication mechanism. ...The tribological properties and rolling lubrication performance of recycled nano-lubricants with different cycle stages were preliminarily evaluated using four-ball tribotester and two-high rolling mills. To determine the phase transformation of MoS2 in recycled nano-lubricants, the already used MoS2 nano-lubricant was collected, dried and then analyzed by means of X-ray diffraction (XRD). Molecular dynamics simulation was conducted to analyze the specialized lubrication mechanism of reused MoS2 nano-lubricant. The results revealed that the MoS2 was considered to gradually transform into MoO3 during cold rolling process. Those oxidizing metamorphic MoS2 nano-lubricants still had excellent friction reducing and wear resistance. That indicated MoS2 nano-lubricant could be recycled in cold rolling process. The recirculation of MoS2 nano-lubricant reduced the use of lubricants, the discharge of waste liquid and the production cost. Not only the pollution to environment was relieved, but also resources and costs were saved. The calculation results of adsorption energy between nanoparticles and steel surface further demonstrated the absorbing type of lubricating film in different cycle stages. A lubrication model suitable for MoS2 nano-lubricants under steel strip cold rolling lubrication circulation condition was established to explain their sustainable lubrication mechanism.
•MoS2 nano-lubricant used in cold rolling process was confirmed to be recyclable.•The existence of recycled MoS2 nano-lubricant improved the quality of rolled surface.•The phase transformation of nano-MoS2 during long time recirculation was studied.•Lattice parameter was calculated to explain the sustainable lubrication performance.•Lubrication film evolution model was established to explain lubrication mechanism.
The newly discovered two-dimensional materials can be used to form atomically thin and sharp van der Waals heterostructures with nearly perfect interface qualities, which can transform the science ...and technology of semiconductor heterostructures. Owing to the weak van der Waals interlayer coupling, the electronic states of participating materials remain largely unchanged. Hence, emergent properties of these structures rely on two key elements: electron transfer across the interface and interlayer coupling. Here we show, using graphene-tungsten disulfide heterostructures as an example, evidence of ultrafast and highly efficient interlayer electron transfer and strong interlayer coupling and control. We find that photocarriers injected in tungsten disulfide transfer to graphene in 1 ps and with near-unity efficiency. We also demonstrate that optical properties of tungsten disulfide can be effectively tuned by carriers in graphene. These findings illustrate basic processes required for using van der Waals heterostructures in electronics and photonics.
Bufalin is efficacious in treating various tumors, however, the clinical application of which is restricted by the myocardial toxicity. Developing a smart synergetic delivery system is widely ...considered as a promising therapeutic strategy. To address this issue, a black phosphorus hybrid polypeptides hydrogel was designed to highly load bufalin, and achieved near-infrared (NIR)-controllable drug release with synergistic photothermal-chemo therapeutic effect. Black phosphorus nanosheets (BPNSs) and bufalin were co-loaded in temperature-sensitive supramolecular hydrogel to receive smart hybridization (BP-bufalin@SH). With NIR irradiation (1 W·cm
−2
), BP-bufalin@SH exhibited a rapid and large temperature increase and released bufalin via light-controllable manner, with which the side effects of bufalin were greatly decreased. Combined with photothermal-chemo therapeutic effect, BP-bufalin@SH could collapse the mitochondrial transmembrane potential resulting in the irreversible apoptosis of tumor cells, and realize a highly efficient
in vivo
tumor elimination with good biosafety and biocompatibility. This work provides a new hydrogel platform for controlling bufalin release, and thus further promotes the practical application on antitumor therapy.
The influence of MoS
2
–Al
2
O
3
nanofluid as a functional lubricant on the microstructure and corrosion resistance of hot-rolled steel surface was studied. Because of the excellent lubrication ...performance of the nanofluid, the rolled surface quality improved with a 18.2% and 69.5% reduction in surface roughness and oxide scale thickness, respectively, when compared with the base-fluid without nanoparticles. The further microstructure characterization determined that the grain size, local misorientation and deformed grain fraction of the steel decreased significantly. A diffusion layer of Al
2
O
3
, FeS and FeMo
4
S
6
was found in the outer oxide layer of rolled surface. Closely arranged Al
2
O
3
grains inhibited the oxidation of steel strips that the oxidation activation energy was increased by about 14.5%. Through density functional theory (DFT) calculation, the formation of FeS and FeMo
4
S
6
was attributed to the migration of Mo and S atoms from MoS
2
into the Fe lattice through substitutional and interstitial diffusion, respectively, with the energy barrier of 0.84 eV and 0.54 eV. Finally, the protection of diffusion layer, reduction in surface defects, and alleviation of residual stress and deformation resulted in the enhancement of corrosion resistance. This study provides a possible route to achieve surface enhancement during the hot rolling process.
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As a hot topic in recent years, molecular dynamics (MD) simulation has become an effective tool in tribochemistry and lubrication investigations, which provides unique insight on ...dealing with these issues from atomic scale. This review paper presents an overview of recent MD simulation studies on revealing the friction laws, wear mechanism and lubrication performance of materials and lubricants, which aims to provide guidance and reference for future theoretical investigations on revealing the essence of friction, wear and lubrication. MD simulation researches upon the tribology, tribochemistry and lubrication are summarized, focusing on the field of friction and wear mechanism, nano-tribology, liquid lubricants, lubricant additives, superlubricity phenomenon, etc. Besides, the challenges and problems remain to be considered, as well as future development directions of MD simulation are briefly discussed. With the help of MD method, the obstacle to tribology research caused by insufficient experimental methods can be reduced in the future.
Thermal-assisted and stress-induced triboreactions at friction interface.
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Tribology plays a crucial role in progress of industry and engineering. The dependence of interface ...conditions and interfacial reactions provides the strategies for friction reduction as well as anti-wear in industrial processes. That is to modify the surface structure of materials or tune the properties of lubricants. This review provides an overview on the important interface conditions and surface-induced tribological reactions with emphasis on the underlying of their formation and action mechanism. The tribological features of asperity, debris and surface texture are firstly dictated. Then the main surface-induced physicochemical reactions including wetting/dewetting, deposition/adsorption are discussed. In particular, the thermal, mechanical and electrical effects that trigger tribochemical reactions are also addressed. Finally, some deficiencies in related investigations are summarized, with perspectives for the development of tribology in both science research and industrial application.
The tribological properties of nanofluids are influenced by multiple factors, and the interrelationships among the factors are deserving of further attention. In this paper, response surface ...methodology (RSM) was used to study the tribological behavior of reduced graphene oxide–Al2O3 (rGO-Al2O3) nanofluid. The interaction effects of testing force, rotational speed and nanoparticle concentration on the friction coefficient (μ), wear rate (Wr) and surface roughness (Ra) of steel disks were investigated via the analysis of variance. It was confirmed that all the three input variables were significant for μ and Wr values, while testing force, nanoparticle concentration and its interaction with testing force and rotational speed were identified as significant parameters for Ra value. According to regression quadratic models, the optimized response values were 0.088, 2.35 × 10−7 mm3·N−1·m−1 and 0.832 μm for μ, Wr and Ra, which were in good agreement with the actual validation experiment values. The tribological results show that 0.20% was the optimum mass concentration which exhibited excellent lubrication performance. Compared to the base fluid, μ, Wr and Ra values had a reduction of approximately 45.6%, 90.3% and 56.0%. Tribochemical reactions occurred during the friction process, and a tribofilm with a thickness of approximately 20 nm was generated on the worn surface, consisting of nanoparticle fragments (rGO and Al2O3) and metal oxides (Fe2O3 and FeO) with self-lubrication properties.
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