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• NDRG2 is highly expressed in the plasma of IS patients. • Low expression of mTOR is identified in plasma of IS patients. • The PI3K/Akt/mTOR pathway is impaired by NDRG2 via dephosphorylation. • Blockage of NDRG2 inhibits neuronal apoptosis and autophagy. • BEZ235 reverses the inhibitory effect of sh-NDRG2 on neuronal apoptosis and autophagy. Astrocytic N-myc downstream-regulated gene 2 (NDRG2), a differentiation- and stress-associated molecule, has been involved in the cause of ischemic stroke (IS). However, its downstream effector in IS remains unclear. This study aimed to characterize expression of NDRG2 in IS patients and rats and to investigate the underlying mechanism. The protein expression of NDRG2 and mammalian target of the rapamycin (mTOR) and the extent of mTOR phosphorylation in plasma of IS patients were detected by ELISA. An oxygen-glucose deprivation model was established in mouse neuronal cells CATH.a, followed by cell counting kit-8, flow cytometry, TUNEL, and western blot assays to examine cell viability, apoptosis and autophagy. Finally, the effect of NDRG2-mediated phosphatidylinositol 3-kinase/protein kinase-B/mTOR (PI3K/AKT/mTOR) pathway on neuronal apoptosis and autophagy was verified in rats treated with middle cerebral artery occlusion. NDRG2 was highly expressed in the plasma of IS patients, while the extent of mTOR phosphorylation was reduced in IS patients. NDRG2 blocked the PI3K/Akt/mTOR signaling through dephosphorylation. Depletion of NDRG2 suppressed apoptosis and autophagy in CATH.a cells, which was reversed by a dual inhibitor of PI3K and mTOR, BEZ235. In vivo experiments confirmed that NDRG2 promoted neuronal apoptosis and autophagy by dephosphorylating and blocking the PI3K/Akt/mTOR signaling. The present study has shown that NDRG2 impairs the PI3K/Akt/mTOR pathway via dephosphorylation to promote neuronal apoptosis and autophagy in IS. These findings provide potential targets for future clinical therapies for IS. [ABSTRACT FROM AUTHOR]

Due to huge carbon emissions associated with the production of Portland cement (PC), the pursuit of sustainable and efficient cementitious materials is a major challenge to manage solid wastes including urban river sludge. As an eco-friendly alternative to PC, granulated blast furnace slag (GBFS)-modified magnesium oxychloride cement (MOC) is innovatively introduced in sludge solidification. The slag modification to MOC and their synergistic efficiency on sludge treatment is systematically evaluated by unconfined compressive strength (UCS), durability and microstructural tests, considering slag dosage, molar ratio of MgO/MgCl 2 and curing age. The obtained results suggest that MOC-slag mixture is efficient in sludge solidification and the inclusion of slag overcomes the strength retraction of MOC solidified sludge. The mechanical behaviour is closely concerned with the formation of phase 5, brucite and C–S–H gels, which imposes a dominant impact on the morphology and microstructure of solidified sludge. Especially, the physic-chemical effect of slag is able to improve the durability of MOC solidified sludge, and induces an enhancement of its long-term stability. The C–S–H gels formed by alkaline activation of slag are the crucial cause of improvement in long-term strength and durability of MOC-slag solidified sludge. In brief, the combined agent of slag-modified MOC shall be deemed as an effective and eco-friendly approach for urban sludge disposal. • Magnesium oxychloride cement is innovatively introduced to dispose of waste sludge. • Slag overcomes strength retraction and improves durability of MOC solidified sludge. • Strength is highly dependent on MgO/MgCl 2 molar ratio, slag dosage and curing time. • MOC-slag system governs strength, durability and microstructure of solidified sludge. • Phase 5, C–S–H and brucite are detected as mechanisms of MOC-slag solidified sludge. [ABSTRACT FROM AUTHOR]

• The evolution of the temperature fields under different stress gradients is studied. • The spatial distribution of high-temperature points is quantitatively analyzed. • The evolution of the average temperature of high-temperature points is analyzed. • Gradient stress affects theevolution characteristics of temperature fields. • The temperature anomalies that occurred on the samples indicate rockburst zones. To study the influence of gradient stress on the evolution characteristics of the temperature field during rockburst, the gradient and hydraulic-pneumatic composite loading true-triaxial apparatus was used to perform the rockburst tests under true-triaxial gradient loading. The temperature data of the unloading face of each sample under gradient loading were continuously recorded using the infrared thermal imager until the rockburst occurred. For the high-temperature points in temperature field, the variance-mean ratio (VMR) was introduced and the relative average temperature of high-temperature points (RAHPT) was proposed for joint analysis to quantify the evolution characteristics of temperature field. It was found that: (1) the VMR and RAHPT adopted in this paper successfully reflect the evolution characteristics of the temperature fields of all the samples under different stress gradients. The VMR and RAHPT increase initially with the increasing loads but subsequently show upward or downward trends in the late stage of loading under different stress gradients; (2) the VMR and RAHPT curves of each sample exhibit similar trends and obvious changes in phase with the increasing load; (3) the samples show obvious differences in rockburst precursors under different stress gradients, and the temperature differentiation of unloading faces appears shortly before the rockbursts, accompanied by the sudden increases in the VMR and RAHPT curves under high stress gradients; (4) the temperature anomalies that occurred on the samples under loading indicate the damage zones of the impending rockbursts. The research results provide a theoretical basis for infrared early-warning technology of rockbursts in underground openings. [ABSTRACT FROM AUTHOR]