Achieving ultrahigh strength in pre-ageing-extruded Mg-Gd-Y-Zn-Mn alloys via ageing treatment

Ultrahigh-strength Mg-9.2Gd-4.4Y-1.0Zn-0.8Mn (wt%) alloys were produced through isothermal ageing at 200 °C applied to pre-ageing-extruded bars. The remarkable thermal stability exhibited by the β and LPSO phases ensures that the recrystallization state of α-Mg grains and the morphology and distribution of secondary phases in peak-aged alloys resemble those observed in the as-extruded alloys at the micron scale. The microstructure of peak-aged alloys is characterized by bimodal α-Mg grains with a pronounced fibrous texture, with the major strengthening phases consisting of prismatic β′ and basal γ′ phases precipitated during ageing. Through solid-solution and pre-ageing treatments, the extruded alloy at peak age demonstrated the highest tensile strength, with an ultimate tensile strength (UTS) of 555 MPa, a tensile yield strength (TYS) of 488 MPa, and an elongation of 5.8%. The considerable enhancement in tensile strength with satisfactory ductility in peak-aged alloys can be attributed to dense number distribution co-precipitation, which increases both basal and non-basal critical resolved shear stresses (CRSS) and inhibits microcrack nucleation and propagation. These findings have significant implications for the advancement of high-strength Mg-Gd-Y-Zn alloys with improved mechanical properties and performance in practical applications

Increased serum exosomal miR-134 expression in the acute ischemic stroke patients

Abstract Background The exosomal miRNAs have been emerged as biomarkers and therapeutic targets for various diseases, however, the function of exosomal miRNAs in stroke remains largely unknown. Methods The blood samples from acute ischemic stroke (AIS) patients and normal controls were collected. The exosomes were isolated from the blood samples, which were confirmed by electron microscopy and western blot with the specific exosomes biomarker CD9, CD63 and Tsg101. Results RT-qPCR analysis showed that exosomal miR-134 was significantly increased in AIS patients within 24 h after stroke onset compared with that of control group. Highly expressed exosomal miR-134 was correlated with the National Institutes of Health Stroke Scale (NIHSS) scores, infarct volume and positively associated with the worse prognosis of the stroke patients. Additionally, the exosomal miR-134 was strong positively correlated with the expression of serum interleukin 6 (IL-6) and plasma high-sensitivity C relative protein (hs-CRP). The receiver operating characteristic (ROC) curve suggested that miR-134 might be a potential factor to discriminate AIS patients from non-stroke controls. Conclusions The exosomal miR-134 as a possible novel biomarker for the diagnosis and prognosis of stroke