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In this study, the nano-TiC/AZ61 composites with different heterogeneous bimodal grain (HBG) structures and uniform structure are obtained by regulating the extrusion speed. The effect of HBG structure on the mechanical properties of the composites is investigated. The increasing ductility and toughening mechanism of HBG magnesium matrix composites are carefully discussed. When the extrusion speed increases from 0.75 mm/s to 2.5 mm/s or 3.5 mm/s, the microstructure transforms from uniform to HBG structure. Compared with Uniform-0.75 mm/s composite, Heterogeneous-3.5 mm/s composite achieves a 116.7% increase in ductility in the plastic deformation stage and almost no reduction in ultimate tensile strength. This is mainly because the lower plastic deformation inhomogeneity and higher strain hardening due to hetero-deformation induced (HDI) hardening. Moreover, Heterogeneous-3.5 mm/s composite achieves a 108.3% increase in toughness compared with the Uniform-0.75 mm/s composite. It is mainly because coarse grain (CG) bands can capture and blunt cracks, thereby increasing the energy dissipation for crack propagation and improving toughness. In addition, the CG band of the Heterogeneous-3.5 mm/s composite with larger grain size and lower dislocation density is more conducive to obtaining higher strain hardening and superior blunting crack capability. Thus, the increased ductility and toughness of the Heterogeneous-3.5 mm/s composite is more significant than that Heterogeneous-2.5 mm/s composite.

Abstract The clinical translation of tumor hypoxia intervention modalities still falls short of expectation, restricted by poor biocompatibility of oxygen‐carrying materials, unsatisfactory oxygen loading performance, and abnormally high cellular oxygen consumption‐caused insufficient hypoxia relief. Herein, a carrier‐free oxygen nano‐tank based on modular fluorination prodrug design and co‐assembly nanotechnology is elaborately exploited, which is facilely fabricated through the molecular nanoassembly of a fluorinated prodrug (FSSP) of pyropheophorbide a (PPa) and an oxygen consumption inhibitor (atovaquone, ATO). The nano‐tank adeptly achieves sufficient oxygen enrichment while simultaneously suppressing oxygen consumption within tumors for complete tumor hypoxia alleviation. Significant, the fluorination module in FSSP not only confers favorable co‐assemblage of FSSP and ATO, but also empowers the nanoassembly to readily carry oxygen. As expected, it displays excellent oxygen carrying capacity, favorable pharmacokinetics, on‐demand laser‐triggerable ATO release, closed‐loop tumor hypoxia relief, and significant enhancement to PPa‐mediated PDT in vitro and in vivo. This study provides a novel nanotherapeutic paradigm for tumor hypoxia intervention‐enhanced cancer therapy.

Five Cr-containing refractory high-entropy alloy (RHEA) coatings were prepared by magnetron sputtering technology and then exposed to static lead–bismuth eutectic to investigate their oxidation resistances at 550–650 °C. The obtained TiNbCrMoV coating had a BCC crystalline structure, while the others were amorphous. The TiNbCrMoV coating exhibited the best corrosion resistance, followed by TiNbZrCrV and CrNbZrMoV coatings, and finally TiCrZrMoV and TiNbZrMoCr coatings. The excellent corrosion resistance of TiNbCrMoV coating was mainly attributed to the presence of grain boundaries which provided the diffusion channels of atoms, thus forming a protective oxide layer. Possible mechanisms were proposed to help understand the corrosion behaviors of these RHEA coatings.

Six kinds of FeCrAl coatings with different Cr and Al contents were irradiated by 6 MeV Au-ions with a damage level of 20 dpa. The results showed that the surface roughness and grain size of the coatings increased significantly after irradiation. Nanoscale precipitation and irradiation-induced twins appeared in the coating with relatively lower Cr content. The increase of Cr content promotes the transformation from irradiation-induced softening to hardening. Changed Al content can cause the change in hardness, but cannot cause the transition of softening and hardening. The underlying evolution mechanism of microstructure and mechanical properties induced by Au-ions irradiation is discussed.

Caffeic acid has been indicated to benefit cholesterol balance, but the effect of pure caffeic acid on atherosclerosis in vivo has not been tested. Given that atherosclerosis and Alzheimer's disease share common features including distracted lipid balance and chronic inflammation, the concurrent effects of caffeic acid on atherosclerotic lesions and cognitive decline were explored here by using the ApoE−/− mice model. A two months' administration of 20 mg/kg caffeic acid or saline was given once two days intraperitoneally to 5-month-old female ApoE−/− mice. We found that the caffeic acid treatment reduced the atherosclerotic lesions in the whole aorta and aortic sinus of the resulting 7-month-old ApoE−/− mice by roughly 50%, compared with the saline control. Meanwhile, the cognitive decline of treated mice were significantly alleviated, as measured by Y-maze and Morris water maze tasks. A reduced accumulation of β-amyloid in the hippocampus was also observed. These effects were associated with elevated serum HDL-c concentration, upregulated ABCA1 and ABCG1 mRNA levels, as well as decrease local inflammation and reduced levels of serum pro-inflammatory cytokines including TNF-α, IL-6 and MCP-1. These obtained results suggested the preventive and therapeutic potential of caffeic acid against atherosclerosis and Alzheimer's disease during aging.

Hydrogen plays an important role in the corrosion of zirconium alloys, and the degree of influence highly depends on the alloy composition and conditions. In this work, the effects of hydrogenation on the corrosion behavior of Zircaloy-4 in water containing 3.5 ppm Li + 1000 ppm B at 360 °C/18.6 MPa were investigated. The results revealed that hydrogenation can shorten the corrosion transition time and increase the corrosion rates of Zircaloy-4. The higher corrosion rates can be ascribed to the larger stress in the oxide film of hydrogenated samples, which can accelerate the evolution of the microstructure of the oxide film. In addition, we also found that hydrogenation has little effect on the t-ZrO2 content in the oxide film and there is no direct correspondence between the t-ZrO2 content and the corrosion resistance of the Zircaloy-4.

In this paper, we will present a collocation approach based on barycentric interpolation functions and finite difference formulation to study the approximate solution of nonlinear Schrödinger equation. We discretize the time derivative by Crank-Nicolson scheme and bring barycentric interpolation functions into action for spatial discretization. Furthermore, consistency analysis of semi discrete collocation scheme is given. For the nonlinear term, we use Newton iterative method to derive the corresponding linear algebraic equations. Finally, numerical examples show that the numerical scheme has high precision and satisfies the mass and energy conservation.

The high-temperature lead-bismuth eutectic (LBE) corrosion resistance and ring compression performance of the Fe15Cr11Al2Si, Fe15Cr11Al0.5Y, and Fe15Cr11Al2Si0.5Y coatings were investigated. Even if the corrosion test temperature reaches 800 °C, all these coatings can effectively protect the steel cladding tube. After the corrosion test temperature exceeded 660 °C, an obvious Al-rich oxide layer was formed on the surface of the coating, and Al element enrichment occurred at the interface between the coating and the substrate. After the corrosion test at 800 °C, holes appeared in the thick interface layer of the Fe15Cr11Al2Si0.5Y coating. The Fe15Cr11Al2Si coating cracked after the ring compression test with a deformation rate of 3%, and the coating peeled off after the deformation rate reached 5%. When the deformation rate reached 5%, there was still no cracking in the Fe15Cr11Al0.5Y coating. When the deformation rate reached 30%, the coating cracked, but the cracked coating was still tightly bonded with the substrate. The Fe15Cr11Al2Si0.5Y coating has the worst compression performance, even if the deformation rate is 1%, the coating still peels off obviously. The underlying mechanism for the evolution of corrosion resistance and compression performance was discussed.

There is no analytical solution to the deflection influence line of catenary hingeless arches nor an explicit solution to the deflection influence line difference curvature of variable section hingeless arches. Based on the force method equation, a deflection influence line analytical solution at any location before and after structural damage is obtained, and then an explicit solution of the deflection influence line difference curvature of the structural damage is obtained. The indexes suitable for arch structure damage identification are presented. Based on analytical theory and a finite element model, the feasibility of identifying damage at a single location and multiple locations of an arch bridge is verified. This research shows that when a moving load acts on a damaged area of an arch structure, the curvature of the deflection influence line difference will mutate, which proves theoretically that the deflection influence line difference curvature can be used for the damage identification of hingeless arch structures. This research has provided theoretical support for hingeless arch bridge design and evaluation. Combined with existing bridge monitoring methods, the new bridge damage identification method proposed in this paper has the potential to realize normal health status assessments of existing arch bridges in the future.

In the present work, a phase-field model was developed to investigate the influence of recrystallization on bubble evolution during irradiation. Considering the interaction between bubbles and grain boundary (GB), a set of modified Cahn-Hilliard and Allen-Cahn equations, with field variables and order parameters evolving in space and time, was used in this model. Both the kinetics of recrystallization characterized in experiments and point defects generated during cascade were incorporated in the model. The bubble evolution in recrystallized polycrystalline of U–Mo alloy was also investigated. The simulation results showed that GB with a large area fraction generated by recrystallization accelerates the formation and growth of bubbles. With the formation of new grains, gas atoms are swept and collected by GBs. The simulation results of bubble size and distribution are consistent with the experimental results.

Patients with ischemic heart disease receiving reperfusion therapy still need to face left ventricular remodeling and heart failure after myocardial infarction. Reperfusion itself paradoxically leads to further cardiomyocyte death and systolic dysfunction. Ischemia/reperfusion (I/R) injury can eliminate the benefits of reperfusion therapy in patients and causes secondary myocardial injury. Mitochondrial dysfunction and structural disorder are the basic driving force of I/R injury. We summarized the basic relationship and potential mechanisms of mitochondrial injury in the development of I/R injury. Subsequently, this review summarized the natural products (NPs) that have been proven to targeting mitochondrial therapeutic effects during I/R injury in recent years and related cellular signal transduction pathways. We found that these NPs mainly protected the structural integrity of mitochondria and improve dysfunction, such as reducing mitochondrial division and fusion abnormalities, improving mitochondrial Ca2+ overload and inhibiting reactive oxygen species overproduction, thereby playing a role in protecting cardiomyocytes during I/R injury. This data would deepen the understanding of I/R-induced mitochondrial pathological process and suggested that NPs are expected to be transformed into potential therapies targeting mitochondria.

Studies of microorganisms from extreme environments can sometimes reveal novel proteins with unique properties. Here, we identified a novel esterase gene (Est33) from an Antarctic bacterium. The protein was expressed and purified for biochemical characterizations. Site-mutation variants including S94A, D205A, and H233A were constructed to explore the structure–function relationship of the catalytic triad of Est33, and we found mutating Ser94, Asp205, and His233 residues lead to a complete loss of enzyme activity. In addition, the catalytic Ser94 located in a conserved pentapeptide motif GVSWG. Phylogenetic analysis showed that Est33 and its closely related homologs belonged to an independent group apart from other known family members, indicating that Est33 represented a new family of esterase. The Est33 enzyme was found to be a cold-active esterase retaining 25%–100% activity from 10°C to 30°C and to have optimal catalytic activity toward p-nitrophenol acetate (30°C and pH7.5). The serine modifying reagent phenylmethylsulfonyl fluoride inhibited the activity of Est33 by 77.34%, while thiol reagents such as dithiol threitol (DTT) activated the enzyme by 3-fold. Metal chelating reagents EDTA had no effects, indicating that Est33 is not a metalloenzyme. Collectively, these results indicate that Est33 constitutes the first member of a novel esterase family XXI that has been identified.

MAX phases are promising candidate structural materials for lead-cooled fast reactors (LFRs) and accelerator-driven sub-critical systems (ADSs) due to their excellent corrosion resistance in liquid LBE. In this work, one of the typical MAX phases, Ti3SiC2, was exposed to the flowing LBE with a saturated oxygen concentration at 500 °C for up to 3000 h. The corrosion behaviors, including the evolution of the corrosion layer, mechanical properties and wettability, were evaluated via X-ray diffraction, a scanning electron microscope equipped with an energy-dispersive X-ray, a microhardness test and contact angle measurement. The results reveal that a corrosion structure with a duplex layer was formed on the sample surfaces. The outer layer was a diffusion layer, which always remained thin (3SiC2.

An anode-supported tubular protonic ceramic fuel cell with BaCe0.7Zr0.1Y0.2O3-δ electrolyte is fabricated using dip-coating technique. Electrochemical performances of the cell are tested at temperatures from 600 to 200 °C, utilizing humidified H2 (3 vol% H2O) as fuel and ambient air as oxidant. With an effective area of 2.3 cm2, the cell yields a peak power density of 465 mW cm−2 at 600 °C and 118 mW cm−2 at 450 °C. Even when the temperature is as low as 200 °C, there is still an output power of 3 mW. Stability of the cell under 600 °C is tested by operating the cell at a constant voltage of 0.7 V. The test lasts for 30 h during which the operating power density decreases rapidly in the first 10 h, then tend to be stable at 300 mW cm−2.

Wire and arc additive manufacturing based on cold metal transfer (WAAM-CMT), as a kind of clean and advanced technology, has been widely researched recently. It was analyzed in detail for the microstructure and mechanical properties of WAAM-CMT printed TiB2/AlSi7Mg0.6 samples fore-and-aft heat treatment in this study. Compared with the grain size of casted AlSi7Mg0.6 samples (252 μm), the grain size of WAAM-CMT printed AlSi7Mg0.6 samples (53.4 μm) was refined, showing that WAAM-CMT process could result in significant grain refinement. Besides, the grain size of WAAM-CMT printed TiB2/AlSi7Mg0.6 samples was about 35 μm, revealing that the addition of TiB2 particles played a role in grain refinement. Nevertheless, the grain size distribution was not uniform, showing a mixture of fine grain and coarse grain, and the mechanical properties were anisotropic of the as-printed samples. This study shows that T6 heat treatment is an efficient way to improve the nonuniform microstructure and eliminate the anisotropy in mechanical properties.

Magnesium (Mg) and their alloys show potential in railway rolling stock applications due to their attractive mechanical properties, developed manufacturing processes, cost efficiency, and affluent resource reserve. In particular, high-strength Mg alloy components are important to lightweighting efforts in the railroad industry. In this review, Mg alloy processing technology for railroad vehicles is discussed with emphasis on energy savings, manipulation convenience, and reduction in friction/wear, vibration, and fatigue damage. It is shown that a Mg alloy train has a theoretical 8.6–12.6% comprehensive weight reduction potential in the equal-strength and equal-stiffness condition, where low-speed trains (metro, light rail train, tram/trolley car, monorail car, suspension train/schwebebahn etc..) exhibit a larger energy-savings than high speed trains. It is evident that the regulations of fabrication, processing, post treatment, assembly/installation, protection, and maintenance/replacement of Mg alloy components for the railroad industry all need further research and development. Keywords: Mg alloys, Lightweight train, Energy savings

Esterases represent an important class of enzymes with a wide variety of industrial applications. A novel hormone-sensitive lipase (HSL) family esterase, Est19, from the Antarctic bacterium Pseudomonas sp. E2-15 is identified, cloned, and expressed. The enzyme possesses a GESAG motif containing an active serine (S) located within a highly conserved catalytic triad of Ser155, Asp253, and His282 residues. The catalytic efficiency (kcat/Km) of Est19 for the pNPC6 substrate is 148.68 s−1mM−1 at 40 °C. Replacing Glu154 juxtaposed to the critical catalytic serine with Asp (E154→D substitution) reduced the activity and catalytic efficiency of the enzyme two-fold, with little change in the substrate affinity. The wild-type enzyme retained near complete activity over a temperature range of 10–60 °C, while ~50% of its activity was retained at 0 °C. A phylogenetic analysis suggested that Est19 and its homologs may represent a new subfamily of HSL. The thermal stability and stereo-specificity suggest that the Est19 esterase may be useful for cold and chiral catalyses.

In this work, the self-corrosion and discharge performance of the as-cast Mg- x Sn ( x = 1, 5, 9 wt%) anodes for primary Mg-air batteries were studied through microstructure characterization, electrochemical testing and discharge experiments. With the increase of Sn content, the volume fraction of the Mg _2 Sn phase increases, promoting dendrite refining. According to the electrochemical test, the Mg-1Sn anode shows a higher open circuit potential, resulting in a stronger electrochemical activity. The polarization curve and electrochemical impedance spectra show the corrosion resistance order as Mg-1Sn > Mg-5Sn > Mg-9Sn. In the discharge measurement, the Mg-1Sn anode achieves the best average discharge voltage, anode efficiency, specific capacity, and energy density under all current densities tested. At 10 mA cm ^−2 , the energy density of Mg-1Sn is 1239.621 mWh g ^−1 , which is higher than the Mg-5Sn anode and Mg-9Sn anode, 37% and 25%, respectively. The optimal discharge performance of the Mg-1Sn anode is mainly attributed to the high electrochemical activity and the micron-sized Mg _2 Sn phase dispersed in the matrix, which facilitates more uniform dissolution.

Graphene, as a rising-star materials, has attracted interest in fabricating lightweight self-lubricating metal matrix composites with superior mechanical and wear properties. In this work, graphene nanoplatelets (GNPs) reinforced AZ31 alloy composites were fabricated by a powder metallurgy technique and then a hot extrusion. The effects of GNPs content (0.5, 1.0, and 2.0 wt.%) on the microstructures, mechanical properties, and wear performance of the extruded GNPs/AZ31 composites were studied. It was found that the addition of GNPs resulted in a weakened basal plane texture and grain refinement of the AZ31 matrix metal. Less than 1.0 wt.% GNPs in GNPs/AZ31 composites resulted in the enhancement in both Vickers hardness and tensile yield strength with acceptable elongation. The Vickers hardness and tensile yield strength of 1.0GNPs/AZ31 composite increased by 4.9% and 9.5% respectively, compared with the unreinforced AZ31. Moreover, the elongation of the composites was about the same as the AZ31 base alloy. Both the friction coefficient and the wear mass loss continuously decreased with the increasing GNPs content, which exhibited a self-lubricating effect. The relationship of the friction coefficient and wear mass loss with the GNPs content could be modeled in terms of the Holliday model and the exponential decay model, respectively. The worn surface morphology revealed that adhesive wear and abrasive wear simultaneously acted in AZ31 alloy. Nevertheless, abrasive wear became the dominant wear mechanism in the GNPs/AZ31 composites.

The semi-solid billets of Mg-2.4Y-4Nd-0.5Zr-1Ni (WE34-1Ni) alloys are fabricated by electro-magnetic induction heating semi-solid treatment at 2.05 kW and 4.10 kW from 580 °C to 625 °C. In this work, the microstructure evolution and mechanical properties of WE34-1Ni alloys are investigated, and the results reveal that with increasing semi-solid temperatures, the average grain size of the solid globules and liquid fraction at the grain boundary gradually increase while the shape factor fluctuates slightly. Compared with 2.05 kW power, the semi-solid billet with 4.10 kW power at 625 °C has more fine homogeneous grains, the lower average size of the solid globules, more liquid fraction. The semi-solid billet with 4.10 kW at 625 °C obtains ideal semi-solid spheroid structure with the solid grains surrounded by a small amount of liquid pools and the best mechanical properties of the semi-solid process parameters. Besides, the elongation as-extruded of WE34-1Ni alloys increased from 21.4 ± 0.7% to 33.2 ± 0.3% at 4.10 kW power and 625 °C via electro-magnetic induction heating semi-solid treatment.

The hot deformation test of the nano silicon carbide (nano-SiC) and carbon nano tubes (CNT) hybrid-reinforced AZ80 matrix composite was performed at compression temperatures of 300−450 °C and strain rates of 0.0001−1 s−1. It could be observed that the flow stress of the nanocomposite rose with the reduction of deformation temperature and the increase of strain rate. The hot deformation behaviors of the composite could be described by the sine-hyperbolic Arrhenius equation, and deformation activation energy (Q) was calculated to be 157.8 kJ/mol. The Q values of the extruded nanohybrid/AZ80 composite in this study and other similar studies on extruded AZ80 alloys were compared in order to analyze the effect of the addition of reinforcement, and the effects of deformation conditions on activation energy were analyzed. Finally, the compression microstructure in an unstable condition was carefully analyzed, and results indicated that the phenomenon of local instability was easy to occur at the compression specimen of the nanohybrid/AZ80 composite under deformation conditions of low temperature with high strain rate (300 °C, 0.1−0.01 s−1), and high temperature with low strain rate (450 °C, 0.0001 s−1).

Atherosclerosis-predominant vasculopathy is a common complication of diabetes with high morbidity and high mortality, which is ruining the patient's daily life. As is known to all, traditional Chinese medicine (TCM) SHENQI compound and western medicine rosiglitazone play an important role in the treatment of diabetes. In particular, SHENQI compound has a significant inhibitory effect on vascular lesions. Here, to explore and compare the therapeutic mechanism of SHENQI compound and rosiglitazone on diabetic vasculopathy, we first built 7 groups of mouse models. The behavioral, physiological and pathological morphological characteristics of these mice showed that SHENQI compound has a more comprehensive curative effect than rosiglitazone and has a stronger inhibitory effect on vascular lesions. While rosiglitazone has a more effective but no significant effect on hypoglycemic. Further, based on the gene expression of mice in each group, we performed differential expression analysis. The functional enrichment analysis of these differentially expressed genes (DEGs) revealed the potential pathogenesis and treatment mechanisms of diabetic angiopathy. In addition, we found that SHENQI compound mainly exerts comprehensive effects by regulating MCM8, IRF7, CDK7, NEDD4L by pivot regulator analysis, while rosiglitazone can rapidly lower blood glucose levels by targeting PSMD3, UBA52. Except that, we also identified some pivot TFs and ncRNAs for these potential disease-causing DEG modules, which may the mediators bridging drugs and modules. Finally, similar to pivot regulator analysis, we also identified the regulation of some drugs (e.g. bumetanide, disopyramide and glyburide etc.) which have been shown to have a certain effect on diabetes or diabetic angiopathy, proofing the scientific and objectivity of this study. Overall, this study not only provides an in-depth comparison of the efficacy of SHENQI compound and rosiglitazone in the treatment of diabetic vasculopathy, but also provides clinicians and drug designers with valuable theoretical guidance.

Carbon nanotube (CNT)-reinforced AZ31 matrix nanocomposites were successfully fabricated using a powder metallurgy method followed by hot extrusion. The influence of CNTs on microstructures, mechanical properties, and wear properties were systematically investigated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), hardness test, tensile test, and wear test. The results revealed that the nanocomposites showed a slightly smaller grain size compared with the matrix and uniform distribution that CNTs could achieve at proper content. As a result, the addition of CNTs could weaken basal plane texture. However, the yield strength and ultimate tensile strength of the composites were enhanced as the amount of CNTs increased up to 2.0 wt. %, reaching maximum values of 241 MPa (+28.2%) and 297 MPa (+6.1%), respectively. The load transfer mechanism, Orowan mechanism, and thermal mismatch mechanism played important roles in the enhancement of the yield strength, and several classical models were employed to predict the theoretical values. The effect of CNT content on the friction coefficient and weight loss of the nanocomposites was also studied. The relationships between the amount of CNTs, the friction coefficient, and weight loss could be described by the exponential decay model and the Boltzmann model, respectively.

Semi-solid feedstock of AZ80 magnesium alloy modified by trace rare-earth Y element (0, 0.2, 0.4, 0.8 wt. %) was fabricated by strain-induced melting activation (SIMA) in the form of extrusion and partial remelting. The effect of Y addition on the microstructure evolution of the extruded and isothermally heat treated alloy was observed by using an optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and quantitative analysis. The results show that the Y addition can refine the microstructure and make the β-Mg17Al12 phases agglomerate. During the subsequent isothermal treatment at 570 °C, the average solid grain size, shape factor and liquid fractions increased with the prolonged soaking time. The smaller spheroidal solid grains and larger shape factor were obtained in the semi-solid microstructure due to Y addition. The coalescence and Ostwald ripening mechanism operated the coarsening process of solid grains simultaneously. The coarsening rate constants of AZ80M1 (0.2 wt. % Y addition) of 164.22 μm3 s−1 was approximately four times less than the un-modified AZ80 alloy of 689.44 μm3 s−1. In contrast, the desirable semi-solid structure featured, with fine and well globular solid grains, an appropriate liquid fraction, and shape factor was achieved in AZ80M1 alloy treated at 570 °C for 20–30 min.