In recent years, there has been growing interest in the near-infrared (NIR) fluorescence imaging of tau fibrils for the early diagnosis of Alzheimer's disease (AD). In order to develop a curcumin-based NIR fluorescent probe for tau fibrils, structural modification of the curcumin scaffold was attempted by combining the following rationales: the curcumin derivative should preserve its binding affinity to tau fibrils, and, upon binding to tau fibrils, the probe should show favorable fluorescence properties. To meet these requirements, we designed a novel curcumin scaffold with various aromatic substituents. Among the series, the curcumin derivative with a (4-dimethylamino-2,6-dimethoxy)phenyl moiety showed a significant change in its fluorescence properties (22.9-fold increase in quantum yield; Kd, 0.77 μM; λem, 620 nm; Φ, 0.32) after binding to tau fibrils. In addition, fluorescence imaging of tau-green fluorescent protein-transfected SHSY-5Y cells with confirmed that detected tau fibrils in live cells.

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RTS (random telegraph signal)-like fluctuation in GateInduced Drain Leakage (GIDL) current of Saddle-Fin (S-Fin) type DRAM cell transistor was investigated for the first time. Furthermore, two types of fluctuation which have apparently different τ high (average time duration of high leakage state) to τ low (average time duration of low leakage state) ratio were investigated, and it was found that the energy difference between bistable levels is similar to that of the junction leakage.