The distributions of electron-transfer dynamics in dye-sensitized TiO2 films are probed using single-molecule microscopy. The time-dependent emission (i.e., blinking dynamics) of rhodamine 6G (R6G) and rhodamine B (RB) sensitized TiO2 films are quantified by constructing cumulative distribution functions of emissive (“on”) and nonemissive (“off”) events. Maximum likelihood estimation (MLE) methods and quantitative goodness-of-fit tests based on the Kolmogorov–Smirnov (KS) statistics are used to establish the best fit to the photophysical data. The on-time distributions for R6G and RB on TiO2 are fit by power laws, but only for emissive durations that last longer than ∼0.7 s. Furthermore, large variations in the power-law exponents are observed when using least-squares fitting as compared to the combined MLE and KS-test approach. The off-time distributions for molecules on TiO2 and glass are not consistent with power laws and are instead well represented by log-normal distributions. Our observations support the hypothesis that electron-transfer processes are responsible for blinking on TiO2 as well as glass substrates. Furthermore, the on-time and off-time distributions are sensitive to the chromophore as well as the substrate. To understand the origin of these power-law and log-normal distributions, single-molecule blinking dynamics are modeled using Monte Carlo simulations based on a three-level system with the rate constants for population and depopulation of the nonemissive state being log-normally distributed (i.e., Albery model). In this framework, the rate constants for FET and BET are log-normally distributed, consistent with a Gaussian distribution of activation energies.

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Purpose Emergency department assessment represents a critical but often missed opportunity to identify elder abuse, which is common and has serious consequences. Among emergency care providers, diagnostic radiologists are optimally positioned to raise suspicion for mistreatment when reviewing imaging of geriatric injury victims. However, little literature exists describing relevant injury patterns, and most radiologists currently receive neither formal nor informal training in elder abuse identification. Methods We present 2 cases to begin characterisation of the radiographic findings in elder abuse. Results Findings from these cases demonstrate similarities to suspicious findings in child abuse including high-energy fractures that are inconsistent with reported mechanisms and the coexistence of acute and chronic injuries. Specific injuries uncommon to accidental injury are also noted, including a distal ulnar diaphyseal fracture. Conclusions We hope to raise awareness of elder abuse among diagnostic radiologists to encourage future large-scale research, increased focus on chronic osseous findings, and the addition of elder abuse to differential diagnoses.

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