Genetic modification of miR-34a enhances efficacy of transplanted human dental pulp stem cells after ischemic stroke

Human dental pulp stem cells(hDPSCs) promote recovery after ischemic stro ke;however,the therapeutic efficacy is limited by the poor survival of transplanted cells.For in vitro expe riments in the present study,we used oxygen-glucose deprivation/reoxygenation in hDPSCs to mimic cell damage induced by ischemia/reperfusion.We found that miRNA-34a-5p(miR-34a) was elevated under oxygen-glucose deprivation/reoxygenation conditions in hDPSCs.Inhibition of miR-34a facilitated the prolife ration and antioxidant capacity and reduced the apoptosis of hDPSCs.Moreove r,dual-luciferase reporter gene assay showed WNT1and SIRT1 as the targets of miR-34a.In miR-34a knockdown cell lines,WNT1 suppression reduced cell prolife ration,and SIRT1 suppression decreased the antioxidant capacity.Togethe r,these results indicated that miR-34a regulates cell prolife ration and antioxidant stress via targeting WNT1 and SIRT1,respectively.For in vivo expe riments,we injected genetically modified hDPSCs(anti34a-hDPSCs) into the brains of mice.We found that anti34a-hDPSCs significantly inhibited apoptosis,reduced cerebral edema and cerebral infarct volume,and improved motor function in mice.This study provides new insights into the molecular mechanism of the cell prolife ration and antioxidant capacity of hDPSCs,and suggests a potential gene that can be targeted to improve the survival rate and efficacy of transplanted hDPSCs in brain after ischemic stroke.

Cs_(2)TiI_(6):A potential lead-free all-inorganic perovskite material for ultrahigh-performance photovoltaic cells and alpha-particle detection

The lead contamination and long-term stability are the two important problems limiting the commercialization of organic–inorganic lead halide perovskites.In this study,through an innovative multi-scale simulation strategy based on the first-principle calculations coupling with drift-diffusion model and Monte Carlo method,a new discovery is shed on the vacancy-ordered double perovskite Cs_(2)TiI_(6),a potential nontoxic and stable perovskite material for high-performance solar cell andα-particle detection.The excellent photon absorption character and ultrahigh carrier mobility(μn=2.26×10^(4)cm^(2)/Vs,μp=7.38×10^(3)cm^(2)/Vs)of Cs_(2)TiI_(6)induce ultrahigh power conversion efficiency(PCE)for both single-junction solar cell(22.70%)and monolithic all-perovskite tandem solar cell(26.87%).Moreover,the outstanding device performance can be remained even in high energy charge particle detection(α-particle)with excellent charge collection efficiency(CCE=99.2%)and mobility-lifetime product(μτh=1×10^(–3)cm^(2)/V).Furthermore,to our surprise,the solar cell andα-particle detector based on Cs_(2)TiI_(6)material are able to withstand ultrahigh fluence proton beam up to 1013 and 1015 p/cm2 respectively,which strongly suggests that semiconductor devices based on Cs_(2)TiI_(6)material are able to apply in the astrospace.The multi-scale simulation connecting from material to device reveals that Cs_(2)TiI_(6)perovskite has the great potential for photovoltaic cells,α-particle detection and even their space application.

Effect of TiAl3 Content on Thermal Shock Resistance of Bionic Self-healing Thermal Barrier Coatings

Inspired by the self-healing function of biological organisms,Bionic Laser Alloying(BLA)process was adopted to fabricate the bionic self-healing Thermal Barrier Coatings(TBCs).The BLA with different fractions of TiAl3 self-healing agent and Ceria and Yttria-Stabilized Zirconia(CYSZ)on the plasma-sprayed 7YSZ TBCs was carried out by a pulsed Nd:YAG laser.The effect of TiAl3 content on the microstructure,phase composition,and thermal shock behaviors of the bionic self-healing TBCs were investigated.Results indicated that the bionic self-healing TBCs had better thermal shock resistance than that of the as-sprayed TBCs.The thermal shock resistance increased first and then decreased with increasing TiAl3 fraction.The thermal shock resistance of the bionic self-healing TBCs with 15%TiAl3 is triple that of the as-sprayed TBCs.On one hand,the columnar crystals and vertical cracks could improve strain compatibility of TBCs during the thermal shock process;on the other hand,the TiAl3 as a self-healing agent reacted with oxygen in air at high temperature to seal the microcracks,thereby delaying the crack connection.