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The solid-state effect plays an important role in excited-state dynamics and luminescence properties of thermally activated delayed fluorescence (TADF) materials. Here, the luminescent mechanism of two novel TADF emitters, PPZTPI and PPZPPI, with aggregation-induced emission (AIE) features are theoretically studied based on the first-principles calculations. The polarisable continuum model (PCM) and the combined quantum mechanics and molecular mechanics (QM/MM) method are used to simulate the solvent environments in toluene and the solid-state effects, respectively. Our results show that both PPZTPI and PPZPPI exhibit excellent TADF and AIE properties with similar but not identical luminescence mechanisms. In the solid state, the delayed fluorescence emission of the two molecules mainly depends on the two-step reverse intersystem crossing process. The molecular radiation rates increase by 1–2 orders of magnitude due to the enhancement of intermolecular interactions in the aggregation. For PPZTPI, the solid-state environment exerts a greater influence on the molecular geometry and electronic structure, non-radiative transitions, excited state dynamics, and emission mechanism due to the substitution of tert-butyl groups and their induced steric hindrance effects. Our theoretical study reasonably elucidates the experimental results and provides valuable information for designing high-efficient AIE-TADF emitters. [ABSTRACT FROM AUTHOR]

A series of novel isosteviol-derived alkenyl ethers were synthesized and structurally characterized by IR, NMR, and HR-MS. The tested compounds are more sensitive to Gram-positive bacteria than to Gram-negative bacteria. In particular, compound 5 exhibited better bacteriostatic activity against B. subtilis with a minimum inhibitory concentration of 2.403 mM, whereas compounds 8 and 10 selectively inhibited the S. aureus strain. [ABSTRACT FROM AUTHOR]

Background: Recent studies have shown the challenges involved in detecting small conflicting vessels (1.0–1.5 mm) on contrast-enhanced (CE) T1 images during stereoelectroencephalography (SEEG) planning. Improving the resolution of non-invasive approaches to identify these vessels is possible and important. We present a superior sagittal sinus mapping–based CE-magnetic resonance venography (CE-MRV) protocol calibrated by craniotomies. Method: Seven patients with epileptic symptoms who received craniotomy were enrolled. CE-MRV was acquired with a bolus mapping of the superior sagittal sinus. Together with the T1 image, 3D veins and the brain surface were visualized. The resolution of the CE-MRV was quantified by measuring the diameter of superficial drainages after exposure of the brain surface during craniotomy. Results: A total of 37 superficial drainages were exposed in the bone windows. CE-MRV visualized all these drainages. On average, one superficial drainage could be found in every 13.2 mm diameter of the bone window. The boundary resolution of the CE-MRV was 0.58–0.8 mm in vessel diameter, while drainages larger than 0.8 mm were visualized consistently. Conclusions: The resolution of the CE-MRV in the present study met the requirement for detection of small conflicting vessels during SEEG planning. The visualized venous landmarks could be used for visual guidance to the surgical zone. As a non-invasive approach, CE-MRV is practical to use in the clinical setting. [ABSTRACT FROM AUTHOR]