The biological effects of radiation dose to organs at risk surrounding tumor target volumes are a major dose-limiting constraint in radiotherapy. This can mean that the tumor cannot be completely destroyed, and the efficacy of radiotherapy will be decreased. Thus, ways to reduce damage to healthy tissue has always been a topic of particular interest in radiotherapy research. Modern radiotherapy technologies such as helical tomotherapy (HT), intensity-modulated radiation therapy (IMRT), and proton radiotherapy can reduce radiation damage to healthy tissues. Recent outcomes of animal experiments show that FLASH radiotherapy (FLASH-RT) can reduce radiation-induced damage in healthy tissue without decreasing antitumor effectiveness. The very short radiotherapy time compared to that of conventional dose-rate radiotherapy is another advantage of FLASH-RT. The first human patient received FLASH-RT in Switzerland in 2018. FLASH-RT may become one of the main radiotherapy technologies in clinical applications in the future. We summarize the history of the development of FLASH-RT, its mechanisms, its influence on radiotherapy, and its future.

Abstract. Nitrate is often found to be associated with atmospheric particles. Surface nitrate can change the hygroscopicity of these particles, and thus impact their chemical reactivity. However, the influence of nitrate on heterogeneous reactions of atmospheric trace gases is poorly understood. In this work, the effects of nitrate on heterogeneous conversion of SO2 with hematite at 298 K are investigated using an in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and a White cell coupled with Fourier transform infrared spectroscopy (White cell-FTIR). It is found that nitrate participates in heterogeneous reactions of SO2, accelerates the formation rate of sulfate, and leads to the formation of surface-adsorbed HNO3 and gas-phase N2O and HONO. The results indicate that low to moderate amounts of nitrate significantly enhance the reactivity of hematite–nitrate mixtures, the uptake of SO2, and the formation of sulfate on hematite. For mixtures, the sample containing 24% nitrate exhibits the highest sulfate formation rate, and its corresponding uptake coefficient calculated by geometric surface area is about 5.5 times higher than that of hematite alone. The sample containing 48% nitrate presents the highest Brunauer–Emmett–Teller (BET) uptake coefficient, and the value is about 8 times higher than that of pure hematite. No uptake of SO2 and formation of sulfate are observed on pure nitrate. Evidence presented herein implies a significant contribution of the unreleased HNO3 and HONO in the particles for the conversion of SO2 and the enhanced formation of sulfate in the atmosphere. A possible mechanism for the influence of nitrate on the heterogeneous conversion of SO2 on hematite is proposed, and atmospheric implications based on these results are discussed.

Developing hollow self-supported nanotube arrays with hierarchical microporous and abundant multiactive sites shows great promise for oxygen evolution reaction (OER) electrocatalysis. Herein, a facile and low-cost strategy of NiCo2S4 hollow nanotubes arrays decorated with CeO x nanoparticles (NPs) assembled on a flexible support carbon cloth (CC) for enhanced OER performance is reported. The obtained hierarchical nanoarrays CeO x /NiCo2S4/CC exhibited excellent activity toward OER with an overpotential (270 mV) at 10 mA cm–2, relatively weak Tafel slope, and distinguished durability. CeO x /NiCo2S4/CC nanoarrays not only provide fast electronic transmission and well-defined connection to the substrate but also defective sites and electron transfer by the introduction of CeO x NPs. This new strategy was offered to construct low-cost and effectively hierarchical structural electrocatalysts containing rare-earth species.

Fluorescence lifetime imaging provides more possibility of in vivo multiplexing in second near infrared (NIR‐II) window. However, it still faces the obstacle that fluorescent probes with differentiable lifetime often exhibit quite different fluorescence intensity, especially the short lifetime usually accompanies with a weak fluorescence intensity, resulting in the difficulty for simultaneously decoding multiplexed lifetime information due to the interference of background noise. To facilitate high‐fidelity lifetime multiplexed imaging, we developed a series of Er3+ doped double interface fluorescent nanoprobes (Er‐DINPs): α‐NaYF4@NaErF4: Ce@NaYbF4@NaErF4: Ce@NaYF4 with strong fluorescence intensity and easily distinguishable fluorescence lifetime. Both in vitro and in vivo experimental results confirmed the advantage of these probes with comparable fluorescence intensity for high‐fidelity multiplexed lifetime bioimaging.

In situ monitoring of tissue regeneration progression is of primary importance to basic medical research and clinical transformation. Despite significant progress in the field of tissue engineering and regenerative medicine, few technologies have been established to in situ inspect the regenerative process. Here, we present an integrated second near-infrared (NIR-II, 1000–1700 nm) window in vivo imaging strategy based on 3D-printed bioactive glass scaffolds doped with NIR-II ratiometric lanthanide-dye hybrid nanoprobes, allowing for in situ monitoring of the early inflammation, angiogenesis, and implant degradation during mouse skull repair. The functional bioactive glass scaffolds contribute to more effective bone regeneration because of their excellent angiogenic and osteogenic activities. The reliability of ratiometric fluorescence imaging, coupled with low autofluoresence in the NIR-II window, facilitates the accuracy of in vivo inflammation detection and high-resolution visualization of neovascularization and implant degradation in deep tissue.