Rabbit Anti-Human Tau (phospho Thr231) monoclonal antibody, clone 2I7M7

The fine structure of the band edge exciton and the dark exciton photoluminescence (PL) are topics of significant interest in the research of semiconducting metal halide perovskite nanocrystals, with several conflicting reports on the level ordering of the bright and dark states and the accessibility of the emitting dark states. Recently, we observed the intense dark exciton PL in strongly confined CsPbBr3 nanocrystals at cryogenic temperatures, in contrast to weakly confined nanocrystals lacking dark exciton PL, which was explained by the confinement enhanced bright-dark exciton splitting. In this work, we investigated the size-dependence of the dark exciton photoluminescence properties in CsPbBr3 and CsPbI3 quantum dots in the strongly confined regime, showing the clear role of confinement in determining the bright-dark energy splitting (Delta E-BD) and the dark exciton lifetime (tau (D)). We observe the increase in both Delta E-BD and tau (D) with increasing quantum confinement in CsPbBr3 and CsPbI3 QDs, consistent with the earlier predictions on the size-dependence of Delta E-BD and tau (D). Our results show that quantum confinement plays a crucial role in determining the accessibility to the dark exciton PL and its characteristics in metal halide perovskite nanocrystals.

Purpose PET is a useful tool for detecting the presence and extent of brain tau accumulation. However, most first-generation tau PET tracers are limited for high off-target binding and detection of tau in non-Alzheimer disease (AD). This study evaluated potential clinical applications of(18)F-PI-2620 as a novel PET tracer with a high binding affinity for tau deposition in AD and non-AD tauopathies. Methods Twenty-six participants diagnosed with either mild cognitive impairment, probable AD, frontotemporal dementia, or parkinsonism, as well as healthy controls underwent a 60- to 90-minute brain PET scan after 7 mci (259 MBq) injection of(18)F-PI-2620. Some participants had previous PET scans using(18)F-THK-5351 or(18)F-FP-CIT for dopamine transporter imaging. Results All participants showed no increase in off-target binding in basal ganglia on(18)F-PI-2620 PET images, as noted for first-generation tau tracers. A beta+ mild cognitive impairment or AD patients showed diverse cortical(18)F-PI-2620 uptake in frontotemporoparietal cortex that correlated with Mini-Mental Status Examination (rho = -0.692,P= 0.013). A beta+ Parkinson disease with dementia and (A beta unknown) primary progressive aphasia patients also showed increased(18)F-PI-2620 uptakes in the frontotemporoparietal cortex. Patients with parkinsonism showed increased uptakes in the pallidum compared with A beta- healthy controls (left: 1.41 +/- 0.14 vs 1.04 +/- 0.13,P= 0.014; right: 1.18 +/- 0.16 vs 0.95 +/- 0.07,P= 0.014). Conclusions F-18-PI-2620 PET might be a sensitive tool to detect cortical tau deposits in patients with A beta+ AD and A beta+ non-AD tauopathies. Furthermore, this study showed that "off-target" binding in the basal ganglia does not affect(18)F-PI-2620.