Blue emissions in organic light-emitting devices (OLEDs) are of great significance for their application in full color flat-panel displays and white lightings. [1] However, high-performance blue emitters are still relatively rare. In OLEDs, the injected electrons and holes recombine to form singlet and triplet excitons in the ratio of 1:3, according to the spin statistics, whereas only singlet exciton can decay radiatively in fluorescent materials. [2] Approximately 75% of the triplet excitons are wasted in nonradiative processes, leading to an upper limit of the internal quantum efficiency (IQE) of only 25% in conventional fluorescent devices. One of the methods to enhance the efficiency of OLEDs is to make use of the nonemissive triplet excitons. [3] Phosphorescent OLEDs (PhOLEDs) based on Ir, Pt, and Os organic-metal complexes can approach 100% IQE, which is attributed to the heavy-atom effect. [4] Yet, pure-blue and deep-blue phosphors with Commission Internationale de l'Eclairage (CIE) y values smaller than 0.15 are particularly scarce due to the inherently great challenge in their molecular design; similarly, proper host materials with a large band gap that allows for the refinement of the triplet excitons in devices are also rare. Therefore, it is important to find a way to develop efficient, stable, pure-and deep-blue fluorescent materials. In principle, new-generation, purely organic fluorescent materials can also utilize the nonemissive triplet excitons and achieve high efficiency by converting triplet excitons into singlet excitons. The main mechanisms involve triplet-triplet annihilation (TTA), thermally activated delayed fluorescence (TADF) and the "hot exciton" channel. [5] Essentially, both the TTA and TADF processes can promote the external quantum efficiency (EQE) of the devices by converting excitons from the lowest triplet excited state (T 1 ) to the lowest singlet excited state (S 1 ). Experimental results have confirmed that devices based on TTA and TADF materials can realize a high EQE with a breakthrough of the spin statistical limitation. [6] Although a high EQE has been obtained in TTA and TADF materials, pure-and deep-blue emitters with high efficiency and stability are still exiguous. Unlike TTA and TADF materials, the "hot exciton" materials reported by our group highlight the reverse intersystem crossing from Purely organic electroluminescent materials, such as thermally activated delayed fluorescent (TADF) and triplet-triplet annihilation (TTA) materials, basically harness triplet excitons from the lowest triplet excited state (T 1 ) to realize high efficiency. Here, a fluorescent material that can convert triplet excitons into singlet excitons from the high-lying excited state (T 2 ), referred to here as a "hot exciton" path, is reported. The energy levels of this compound are determined from the sensitization and nanosecond transient absorption spectroscopy measurements, i.e., small splitting energy between S 1 and T 2 and rather large T 2 -T 1 energy gap, which are expected to...
These findings demonstrated that an ophthalmic preservative, benzalkonium chloride, induced a dry eye syndrome in rabbits with damage to the cornea and conjunctiva, decreased aqueous tear basal secretion, goblet cell loss, and MUC5AC deficiency. This rabbit model was consistent with human dry eye syndrome in both aqueous tear and mucin deficiency and may be appropriate for studying dry eye syndrome.
Herein, a simple aza-aromatic compound dibenzo[a,c]phenazine (DPPZ), which exhibits single-molecule white light with a ternary emission, consisting of simultaneous fluorescence (S 1 →S 0 ) and dual room-temperature phosphorescence (RTP, T 2 →S 0 and T 1 →S 0 ) is reported. The Commission Internationale de l' Éclairage coordinates of DPPZ powder are (0.28, 0.33). To everyone's knowledge, this is the first case to achieve single-molecule white emission with ternary emission of fluorescence and dual RTP. This finding provides a prototype strategy to realize low-cost, stable pure organic singlemolecule white light emission with three standard primary colors through further precise modulation of excited states.
f Dehalococcoides mccartyi strains are obligate organohalide-respiring bacteria harboring multiple distinct reductive dehalogenase (RDase) genes within their genomes. A major challenge is to identify substrates for the enzymes encoded by these RDase genes. We demonstrate an approach that involves blue native polyacrylamide gel electrophoresis (BN-PAGE) followed by enzyme activity assays with gel slices and subsequent identification of proteins in gel slices using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RDase expression was investigated in cultures of Dehalococcoides mccartyi strain BAV1 and in the KB-1 consortium growing on chlorinated ethenes and 1,2-dichloroethane. In cultures of strain BAV1, BvcA was the only RDase detected, revealing that this enzyme catalyzes the dechlorination not only of vinyl chloride, but also of all dichloroethene isomers and 1,2-dichloroethane. In cultures of consortium KB-1, five distinct Dehalococcoides RDases and one Geobacter RDase were expressed under the conditions tested. Three of the five RDases included orthologs to the previously identified chlorinated ethene-dechlorinating enzymes VcrA, BvcA, and TceA. This study revealed substrate promiscuity for these three enzymes and provides a path forward to further explore the largely unknown RDase protein family.
This paper presents a computational vascular fluid-structure interaction (FSI) methodology and its application to patient-specific aneurysm models of the middle cerebral artery bifurcation. A fully coupled fluid-structural simulation approach is reviewed, and main aspects of mesh generation in support of patient-specific vascular FSI analyses are presented. Quantities of hemodynamic interest such as wall shear stress and wall tension are studied to examine the relevance of FSI modeling as compared to the rigid arterial wall assumption. We demonstrate the importance of including the flexible wall modeling in vascular blood flow simulations by performing a comparison study that involves four patient-specific models of cerebral aneurysms varying in shape and size.
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