Ti 3 C 2 T x MXene with an organ-like structure was synthesized from Ti 3 AlC 2 (MAX phase) through the typical hydrofluoric (HF) acid etching method. Ti 3 C 2 T x MXene was further alkaline-treated with a sodium hydroxide solution to obtain alkalized Ti 3 C 2 T x . Room-temperature planar-type gas-and humidity-sensing devices were also fabricated by utilizing Ti 3 C 2 T x MXene and alkalized Ti 3 C 2 T x sensing material based on the dip coating method, respectively. The intercalation of the alkali metal ion (Na + ) and the increase of the surface terminal oxygen−fluorine ratio ([O]/[F]) in Ti 3 C 2 T x can effectively improve humidity-and gas-sensing properties at room temperature. The developed alkalized Ti 3 C 2 T x sensor exhibited excellent humidity-sensing characteristics (approximately 60 times response signal change) in the relative humidity (RH) with a range of 11−95% and considerable NH 3 sensing performance (28.87% response value to 100 ppm of NH 3 ) at room temperature. The improvement of NH 3 and humidity-sensing properties indicated that alkalized Ti 3 C 2 T x has great potential in chemical sensors, especially in NH 3 and humidity sensors. KEYWORDS: MXene, organ-like structure, alkalized Ti 3 C 2 T x , NH 3 and humidity sensing, room temperature

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Development of therapeutic vaccines/strategies to control chronic hepatitis B virus (HBV) infection (CHB) has been challenging due to HBV-induced tolerance. In this study, we explored strategies for breaking tolerance and restoring the immune response to the HBV surface antigen in tolerant mice. We demonstrated that immune tolerance status is attributed to the level and duration of circulating HBsAg in HBV carrier models. Removal of circulating HBsAg by a monoclonal anti-HBsAg antibody in tolerant mice could gradually reduce tolerance and reestablish B cell and CD4+ T cell responses to subsequent Engerix-B vaccination, producing protective IgG. Furthermore, HBsAg-specific CD8+ T cells induced by the addition of a TLR agonist, resulted in clearance of HBV in both serum and liver. Thus, generation of protective immunity can be achieved by clearing extracellular viral antigen with neutralizing antibodies followed by vaccination.

Activation of metabolic signalling by IL-15 is required for natural killer (NK) cell development. Here we show that Tsc1, a repressor of mTOR, is dispensable for the terminal maturation, survival and function of NK cells but is critical to restrict exhaustive proliferation of immature NK cells and activation downstream of IL-15 during NK cell development. Tsc1 is expressed in immature NK cells and is upregulated by IL-15. Haematopoietic-specific deletion of Tsc1 causes a marked decrease in the number of NK cells and compromises rejection of ‘missing-self' haematopoietic tumours and allogeneic bone marrow. The residual Tsc1-null NK cells display activated, pro-apoptotic phenotype and elevated mTORC1 activity. Deletion of Raptor, a component of mTORC1, largely reverses these defects. Tsc1-deficient NK cells express increased levels of T-bet and downregulate Eomes and CD122, a subunit of IL-15 receptor. These results reveal a role for Tsc1-dependent inhibition of mTORC1 activation during immature NK cell development.

The design of semiconductor metal oxides (SMOs) with well-ordered porous structure has attracted tremendous attention owing to their larger specific surface area. Herein, three-dimensional inverse opal InO microspheres (3D-IO InO MSs) were fabricated through one-step ultrasonic spray pyrolysis (USP) which employed self-assembly sulfonated polystyrene (S-PS) spheres as a sacrificial template. The spherical pores observed in the 3D-IO InO MSs had diameters of about 4 and 80 nm. Subsequently, the catalytic palladium oxide nanoparticles (PdO NPs) were loaded on 3D-IO InO MSs via a simple impregnation method, and their gas sensing properties were investigated. In a comparison with pristine 3D-IO InO MSs, the 3D-IO PdO@InO MSs exhibited a 3.9 times higher response (R/R = 50.9) to 100 ppm acetone at 250 °C and a good acetone selectivity. The detection limit for acetone could extend down to ppb level. Furthermore, the 3D-IO PdO@InO MSs-based sensor also possess good long-term stability. The extraordinary sensing performance can be attributed to the novel 3D periodic porous structure, highly three-dimensional interconnection, larger specific surface area, size-tunable (meso- and macroscale) bimodal pores, and PdO NP catalysts.

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