Imaging mass spectrometry (IMS) enables untargeted, highly multiplexed mapping of molecular species in biological tissue with unparalleled chemical specificity and sensitivity. However, most IMS platforms lack microscopy-level spatial resolution and cellular morphological contrast, necessitating subsequent histochemical staining, microscopic imaging, and advanced image registration to correlate/link molecular distributions with specific tissue features and cell types. We present a diffusion model-based virtual histological staining approach that enhances spatial resolution and digitally introduces cellular morphological contrast into mass spectrometry images of label-free human tissue. Blind testing on human kidney tissue demonstrated that the virtually stained images of label-free samples closely match their histochemically stained counterparts (with periodic acid-Schiff staining), showing high concordance in identifying key renal pathology structures despite using IMS data with 10-fold larger pixel size. Additionally, our approach uses optimized noise sampling during the diffusion model's inference to achieve reliable and repeatable virtual staining. We believe this virtual staining method will open avenues for IMS-based biomedical research.

Tidal flats are critical coastal ecosystems, with their geomorphic characteristics traditionally understood to be primarily influenced by tidal, wave, and storm forces. This study investigates the impact of rainfall on the morphodynamics of upper tidal flats by combining hydrodynamic-sediment data, meteorological rainfall records, and video monitoring at the Chongming Dongtan tidal flat in the Yangtze River Estuary, China. We show that rainfall significantly increases suspended sediment transport and accelerates tidal channel elongation. Notably, rainfall events—though occurring during only 25 % of observed tidal inundation periods—accounted for 62 % of cumulative net sediment transport. This disproportionate efficiency compared to tidal forcing stems from the rainfall-induced hydraulic connectivity between expansive supratidal areas and tidal channels, where concentrated runoff convergence intensifies scour dynamics. These findings challenge the traditional view of tidal flat dynamics, suggesting that rainfall is a more influential driver of morphodynamic change than previously recognized.