ABSTRACT
Multifunctional, flexible, and robust thin films capable of operating in demanding harsh temperature environments are crucial for various cutting-edge applications. This study presents a multifunctional Janus film integrating highly-crystalline Ti3C2Tx MXene and mechanically-robust carbon nanotube (CNT) film through strong hydrogen bonding. The hybrid film not only exhibits high electrical conductivity (4250 S cm-1), but also demonstrates robust mechanical strength and durability in both extremely low and high temperature environments, showing exceptional resistance to thermal shock. This hybrid Janus film of 15 µm thickness reveals remarkable multifunctionality, including efficient electromagnetic shielding effectiveness of 72 dB in X band frequency range, excellent infrared (IR) shielding capability with an average emissivity of 0.09 (a minimal value of 0.02), superior thermal camouflage performance over a wide temperature range (- 1 to 300 °C) achieving a notable reduction in the radiated temperature by 243 °C against a background temperature of 300 °C, and outstanding IR detection capability characterized by a 44% increase in resistance when exposed to 250 W IR radiation. This multifunctional MXene/CNT Janus film offers a feasible solution for electromagnetic shielding and IR shielding/detection under challenging conditions.
ABSTRACT
Here, we examine peripheral blood memory T cell responses against the SARS-CoV-2 BA.4/BA.5 variant spike among vaccinated individuals with or without Omicron breakthrough infections. We provide evidence supporting a lack of original antigenic sin in CD8+ T cell responses targeting the spike. We show that BNT162b2-induced memory T cells respond to the BA.4/BA.5 spike. Among individuals with BA.1/BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.4/BA.5 spike increased. In a subgroup with BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.2-mutated spike region increased and correlated directly with responses against the BA.4/BA.5 spike, indicating that BA.2 spike-specific CD8+ T cells elicited by BA.2 breakthrough infection cross-react with the BA.4/BA.5 spike. We identified CD8+ T cell epitope peptides that are present in the spike of BA.2 and BA.4/BA.5 but not the original spike. These peptides are fully conserved in the spike of now-dominant XBB lineages. Our study shows that breakthrough infection by early Omicron subvariants elicits CD8+ T cell responses that recognize epitopes within the spike of newly emerging subvariants.