Type 2 diabetes mellitus (T2DM) is a metabolic disease primarily characterized by insulin resistance (IR) and insufficient insulin secretion. The unfolded protein response (UPR) overactivation ...induced by endoplasmic reticulum stress (ERS) appears to play a key role in this process, although the exact pathogenesis of T2DM is not fully understood. Studies have demonstrated that appropriate exercise can regulate ERS in the heart, liver, pancreas, skeletal muscle, and other body tissues leading to an improvement in diabetes and its complications. However, the exact mechanism remains unclear. By analyzing the relationship between ERS, T2DM pathology, and exercise intervention, this review concludes that exercise can increase insulin sensitivity, inhibit IR, promote insulin secretion and alleviate T2DM by regulating ERS. This paper specifically reviews the signaling pathways by which ERS induces diabetes, the mechanisms of exercise regulation of ERS in diabetes, and the varying effects of different types of exercise on diabetes improvement through ERS mechanisms. Physical exercise is an effective non-pharmacological intervention for T2DM. Thus, further exploration of how exercise regulates ERS in diabetes could refine "precision exercise medicine" for diabetes and identify new drug targets.
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•Endoplasmic reticulum stress is involved in the occurrence and development of type 2 diabetes.•Exercise can improve diabetes by regulating endoplasmic reticulum stress.•Different types of exercise have varying effects on regulating diabetes.
•FC-TC4 and AC-TC4 alloys with more content of α phase were obtained by heat treatment.•Nano twins of TiV and TiAl3 were formed separately in FC-TC4 and AC-TC4 alloys.•Refined recrystallized grain ...and more high-angle grain boundaries of AC-TC4 alloy enhanced its mechanical properties.•The passivating ability of AC-TC4 alloy was best among three samples because of its microstructure.•The cavitation erosion resistance of Ti6Al4V alloys in artificial seawater was closely related to their mechanical properties and passivating ability.
The investigate about the effect of the microstructure of Ti6Al4V alloy on its cavitation erosion and corrosion properties in marine can provide the key basis for the application. On the basis of as-received Ti6Al4V(TC4) alloy, FC-TC4 and AC-TC4 alloys were prepared by heat treatment with the cooling method of a furnace and atmospheric environment, respectively. Then the microstructure evolutions of three samples were scrutinized and the effect of microstructure on their cavitation erosion and corrosion resistance was explored. The results showed that more recrystallized grains formed as well as its content of α grains and high-angle grain boundaries increased in AC-TC4 alloy. To FC-TC4 alloy, there was obvious grain growth apart from recrystallization. Moreover, many nanotwins of TiV and TiAl3 were formed separately in FC-TC4 and AC-TC4 alloys due to the dislocation migration during heat treatment. The microstructure evolution led the hardness and elastic modulus of AC-TC4 alloy were the best, followed by FC-TC4 alloy, that of TC4 were the worst. Similarly, passivating ability of AC-TC4 alloy was the best among three samples because of its microstructure. Although cracks extended along the grain boundaries under the action of continual cavitation erosion, the passivation film formed by TiO2 and Al2O3 would enhance their resistance to further corrosion and cavitation erosion in artificial seawater.
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An in situ strategy for fabrication of reduced graphene oxide/fused silica (rGO/FS) composites using 3-aminopropyltriethoxysilane as surfactant is reported. GO nanosheets were bound to FS particles ...by an electrostatic assembly between ultra thin negatively charged GO sheets and positively charged amino-modified FS particles. After spark plasma sintering, rGO/FS bulk composites have been produced from the GO and FS composite particles with GO being reduced to rGO in vacuum at high temperatures. Results show that rGO sheets were well dispersed in the matrix, and conductivity of these rGO/FS composites at room temperature was strongly dependent on the rGO nanosheet concentration. i.e., the conductivity of rGO/FS was increased to 10−4S/cm when a conducting network was formed inside the composites. The effect of GO nanosheets on the mechanical properties of rGO/FS bulk composites was also investigated. The addition of 1wt.% GO sheets to FS resulted in 72% increase in Vickers hardness, indicating the stress transfering from the FS matrix to the rigid rGO sheets. With the same rGO content, the fracture toughness of the as-prepared composites was increased by 74%. The main toughening mechanisms were thought to be crack deflection, crack branching, pulling-out and bridging of the rGO sheets.
Adaptive NiCrAlY–Ag–Mo composite coating was deposited by atmospheric plasma spraying and its tribological properties from 20°C to 800°C under unlubricated conditions were evaluated using CSM high ...temperature tribometer. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the coating and the corresponding wear tracks to determine the lubrication mechanisms. The results showed that NiCrAlY–Ag–Mo composite coating exhibited low friction coefficients around 0.3 in the entire temperature range and its wear rates were at the order of 10−5mm3/Nm at all test temperatures. Characterization of NiCrAlY–Ag–Mo coating revealed that silver provided lubrication at temperatures below 400°C. Silver molybdate and molybdenum oxide, which were formed as the temperature raised, act as lubricants at higher temperature (above 400°C). Meanwhile, the formation mechanism of silver molybdate and molybdenum oxide was also briefly discussed.
•Adaptive NiCrAlY–Ag–Mo composite coating was firstly produced by atmospheric plasma spraying technology.•The composite coating exhibited show good cohesive strength and low porosity.•The composite coating shows stable and low friction coefficients around 0.3 from 20°C to 800°C.
Iron-based metallic glass coatings (denoted as FeWCrNiMoBSiC) were prepared on 1Cr18Ni9Ti stainless steel cylinders by atmospheric plasma spraying at different parameters. The morphology, ...microstructure, and crystalline structure of as-prepared Fe-based metallic glass coatings were analyzed by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. A Pycnometer and a Vickers hardness tester were adopted to measure the porosity and microhardness of iron-based metallic glass coatings. Moreover, differential scanning calorimetry analysis was conducted to investigate the crystallization behavior of various iron-based metallic glass coatings, and a ball-on-disk tribometer was performed to evaluate the tribological properties of the coatings coupled with silicon nitride ceramic balls under unlubricated conditions. It has been found that the microhardness of iron-based metallic glass coatings increases with increasing plasma arc power, which is related to the degree of melting of feedstock powders and the compactness of as-prepared coatings. Besides, the phase compositions of as-sprayed coatings consist of amorphous structure and limited crystalline structure, and the contents of the amorphous structure and crystalline structure vary with plasma arc power. Moreover, iron-based metallic glass coatings deposited at different plasma arc powers show similar steady-state friction coefficients (0.8–0.9), but their wear rate varies with varying plasma arc power. Particularly, iron-based metallic glass coating with next to the highest hardness exhibits the best anti-wear ability, which is the outcome of the compromise between the hardness and brittle fracture as well as abrasive wear of the coatings during sliding process.
•The compactness of iron-based coatings is ameliorated at elevated spraying power.•The phase compositions of iron-based coatings include amorphous and crystalline structures.•Iron-based coatings deposited at different spraying powers show similar steady-state friction coefficients.•The wear rate of iron-based coatings varies with varying spraying power.
Skeletal muscle aging in rats is a reduction in skeletal muscle mass caused by a decrease in the number or volume of skeletal muscle myofibers. Apoptosis has been recognized to play a key role in ...accelerating the process of skeletal muscle aging in rats. The thioredoxin (Trx) system is a widely expressed oxidoreductase system that controls the cellular reduction/oxidation state and has both potent anti-free radical damage and important pro-growth and apoptosis inhibitory functions. Previous studies have shown that exercise delays skeletal muscle aging. However, it is unclear whether exercise attenuates skeletal muscle aging via the Trx system. Therefore, the present study used the Trx system as an entry point to explore the effect of aerobic exercise to improve skeletal muscle aging in rats and its possible mechanisms, and to provide a theoretical basis for exercise to delay skeletal muscle aging in rats. It was shown that aerobic exercise in senescent rats resulted in increased gastrocnemius index, decreased body weight, increased endurance, decreased skeletal muscle cell apoptosis, increased activity and protein expression of the Trx system, and decreased expression of p38 and ASK1. Based on these findings, we conclude that 10 weeks of aerobic exercise may enhance the anti-apoptotic effect of Trx by up-regulating Trx and Trx reductase (TR) protein expression, which in turn increases Trx activity in rat skeletal muscle, and ultimately alleviates apoptosis in senescent skeletal muscle cells.
•Aerobic exercise alleviates skeletal muscle aging in rats.•Aerobic exercise alleviates ageing-induced apoptosis in skeletal muscle cells in rats.•Aerobic Exercise enhances the activity of the Trx system in aging skeletal muscle in rats.•Aerobic Exercise enhances Trx Anti-Apoptosis in aging skeletal muscle in rats.•Aerobic exercise increases Trx binding to ASK1, inhibits the downstream P38 signaling pathway in aging skeletal muscle.
Adding nano particles can significantly improve the mechanical properties and wear resistance of thermal sprayed Al2O3 coating. However, it still remains a challenge to uniformly incorporate nano ...particles into traditional coatings due to their bad dispersibility. In the present work, nanometer Al2O3 (n-Al2O3) powders modified by KH-560 silane coupling agent were introduced into micrometer Al2O3 (m-Al2O3) powders by ultrasonic dispersion to afford nano/micro composite feedstock, and then four resultant coatings (weight fraction of n-Al2O3: 0%, 3%, 5% and 10%) were fabricated by atmospheric plasma spraying. The features and constitutes of feedstock and as-sprayed coatings, as well as their porosity, bonding strength, microhardness and frictional behaviors were investigated in detail. Results show that the nano/micro composite feedstock with uniform microstructure can be better melted in the spraying process, thereby obtaining coatings with denser microstructure, higher hardness and bonding strength. Added n-Al2O3 has no obvious effect on the friction coefficient of composite coatings, whereas can improve their wear-resistant and reduce the worn degree of counterpart. The wear mechanism of traditional coating is brittle fracture and lamellar peeling, while that of composite coating with weight fraction of n-Al2O3 of 10% is adhesive wear.
Cavitation damage is a concern for stainless steel and other metals in seawater environments, and new coatings are needed to resist such surface damage in that kind of environment. Consequently, a ...NiCr alloy coating, a WC–17Co/NiCr composite coating, a Fe-based metallic glass coating, a WC–(W,Cr)2C–Ni cermet coating, and a WC–17Co cermet coating were prepared on metal alloy substrates using high velocity oxy-fuel spraying (HVOF). The microstructure and phase composition of as-sprayed coatings and substrates were analyzed using optical microscopy and X-ray diffraction. Vicker's microindentation hardness was measured as well. The cavitation erosion behavior of the five kinds of HVOF-sprayed coatings and three kinds of alloys (316 stainless steel, TC4 titanium alloy and ZL101 aluminum alloy) in both deionized water and artificial seawater was evaluated according to ASTM standard method G 32-10. The corrosion behavior of the alloys and HVOF-sprayed coatings in artificial seawater was evaluated by potentiodynamic polarization tests to reveal the correlation between corrosion and cavitation behavior. Based on the test results, an analysis of the microstructural damage processes, and the cavitation–corrosion synergism of the coatings, the WC–17Co cermet coating was found to be the most promising coating to prevent metallic substrates from cavitation damage in seawater.
•Metallographic structure has an important effect on cavitation erosion behavior of alloys.•Porosity and hardness affect cavitation erosion behavior of HVOF-sprayed coatings to some extent.•Fe-based metallic glass coating shows good cavitation erosion behavior in deionized water.•Chemical action of artificial seawater affects cavitation erosion behavior of various materials.•WC–17Co cermet coating has the best cavitation erosion resistance in artificial seawater.
Uric acid (UA) is the final oxidation product of purine metabolism. Hyperuricemia has been previously reported to contribute to vascular endothelial dysfunction and the development of cardiovascular ...diseases, metabolic syndrome and chronic kidney diseases. In addition, it has been reported that fibroblast growth factor 21 (FGF21) can exert regulatory effects on UA‑induced lipid accumulation. Therefore, the present study aimed to investigate the possible role of FGF21 in HUVEC cell injury induced by UA. The study used UA to induce HUVEC cell injury, inhibited sirtuin 1 (Sirt1) expression using EX527 and overexpressed FGF21 by transfection. Subsequently, reverse transcription‑quantitative PCR was performed to measure the mRNA expression levels of FGF21, Sirt1 and inflammatory cytokines TNF‑α, IL‑1β and IL‑6, whereas western blotting was performed to measure their corresponding protein expression levels including FGF21, Sirt1, NLR family pyrin domain containing 3, pro‑caspase1, apoptosis‑associated speck‑like protein containing a CARD, activating transcription factor 4, C/EBP homologous protein and eukaryotic initiation factor 2. Furthermore, dichloro‑dihydro‑fluorescein diacetate staining was performed to measure intracellular reactive oxygen species (ROS) generation in HUVECs. The levels of ROS and nitric oxide were also quantified using commercial assay kits. The results demonstrated that overexpression of FGF21 significantly inhibited UA treatment‑induced endoplasmic reticulum (ER) stress, inflammation and oxidative stress in HUVECs. Furthermore, overexpression of FGF21 significantly activated Sirt1. The sirt1 inhibitor, EX527, significantly abrogated the suppressive effects of FGF21 overexpression on ER stress, inflammation and oxidative stress in UA‑stimulated HUVECs. To conclude, results of the present study suggested that FGF21 may attenuate UA‑induced ER stress, inflammation and vascular endothelial cell dysfunction by activating Sirt1. Therefore, FGF21 may be a potential effective target for the future treatment of vascular endothelial cell dysfunction.
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