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Organic light-emitting diodes (OLEDs) exploiting simple binary emissive layers (EMLs) blending only emitters and hosts have natural advantages in low-cost commercialization. However, previously reported OLEDs based on binary EMLs hardly simultaneously achieved desired comprehensive performances, e.g., high efficiency, low efficiency roll-off, narrow emission bands, and high operation stability. Here, we report a molecular-design strategy. Such a strategy leads to a fast reverse intersystem crossing rate in our designed emitter h -BNCO-1 of 1.79×10 5  s −1 . An OLED exploiting a binary EML with h -BNCO-1 achieves ultrapure emission, a maximum external quantum efficiency of over 40% and a mild roll-off of 14% at 1000 cd·m −2 . Moreover, h -BNCO-1 also exhibits promising operational stability in an alternative OLED exploiting a compact binary EML (the lifetime reaching 95% of the initial luminance at 1000 cd m −2 is ~ 137 h). Here, our work has thus provided a molecular-design strategy for OLEDs with promising comprehensive performance. Multi-resonance thermally activated delayed fluorescent emitters composed of only period-2 elements are important for achieving comprehensive performances. Here, authors report hybridization of organoboron-nitrogen and carbonyl groups in the emitter to achieve a long device operational stability.

Energy level alignment of frontier molecular orbital (FMO) is essential for controlling charge carrier and exciton dynamics in organic light-emitting diodes (OLEDs). However, multiple resonance (MR) emitters with exceptional narrowband luminescence typically suffer from inadequate FMO levels. Herein, a conventional blue MR prototype with a shallow highest occupied molecular orbital (HOMO) level of −5.32 eV is initially employed to reveal the charge carrier and exciton dynamics. Severe hole trapping by its shallow HOMO significantly hinders its transport. More importantly, trapped carriers induce direct exciton formation and recombination at MR emitters in a hyperfluorescent system, leading to triplet accumulation in MR emitters. To resolve these issues, a proof-of-concept wavefunction perturbation strategy is proposed by incorporating cyano motifs at peripheral sites of MR backbone to adjust the energy levels. This approach significantly shifts HOMOs of 0.36 and 0.51 eV without compromising colour purity. The derivative substituting meta -boron position ( m CNDB) exhibits a pure-blue emission peaking at 459 nm with a narrow bandwidth of 13 nm. The detrimental carrier trapping effect is eliminated, enhancing external quantum efficiency to exceeding 23%, maintaining around 20% at 1000 cd m −2 , and improving the device stability. Multiple resonance (MR) emitters with narrowband luminescence typically suffer from inadequate frontier molecular orbital levels. Here, authors incorporate cyano motifs at peripheral sites of the MR backbone to adjust the energy levels, realizing device efficiency of over 23% for stable devices.

Thermally activated delayed fluorescence (TADF) materials with aggregation‐induced emission (AIE) features can overcome aggregation‐caused quenching (ACQ) and emit intensely in aggregate states and thus have attracted enormous attention in the fields of high‐efficiency organic light‐emitting diodes, bioimaging, photodynamic therapy, photocatalysis, etc. However, their corresponding exact working mechanisms at the microscopic level are still far from clear. Herein, by carefully investigating the physical properties of our newly designed TADF material 6‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)nicotinonitrile in various states, we concluded that conformational isomerization plays an important role in realizing high photoluminescence quantum yields in its amorphous neat film state, in which the high‐lying quasi‐axial conformations with non‐TADF features and low‐lying quasi‐equal conformations with TADF characteristics serve as the host matrix and dopant, respectively, thus suppressing ACQ in disordered aggregate states. Our work not only offers a new possible microscopic mechanism by using conformational isomerization for the AIE‐TADF phenomenon but also provides a novel method for designing high‐efficiency AIE‐TADF emitters. Due to conformational isomerization, the emitter exhibits unique AIE‐TADF behavior. This is mainly because the QA conformers act as a host matrix to dilute TADF QE conformations in neat films, thereby suppressing ACQ and achieving high PLQY. This work proposes a new mechanism to understand the AIE‐TADF behaviors and provides a new idea for extending the design of AIE‐TADF materials.

High‐performance nondoped organic light‐emitting diodes (OLEDs) are promising technologies for future commercial applications. Herein, we synthesized two new thermally activated delayed fluorescence (TADF) emitters that enable us, for the first time, to combine three effective approaches for enhancing the efficiency of nondoped OLEDs. First, the two emitters are designed to have high steric hindrances such that their emitting cores will be suitably isolated from those of their neighbors to minimize concentration quenching. On the other hand, each of the two emitters has two stable conformations in solid films. In their neat films, molecules with the minority conformation behave effectively as dopants in the matrix composing of the majority conformation. One hundred percent exciton harvesting is thus theoretically feasible in this unique architecture of “self‐doped” neat films. Furthermore, both emitters have relatively high aspect ratios in terms of their molecular shapes. This leads to films with preferred molecular orientations enabling high populations of horizontal dipoles beneficial for optical out‐coupling. With these three factors, OLEDs with nondoped emitting layers of the respective emitters both achieve nearly 100% exciton utilization and deliver over 30% external quantum efficiencies and ultralow efficiency roll‐off at high brightness, which have not been observed in reported nondoped OLEDs. Two thermally activated delayed fluorescence molecules are designed by strategically integrating three effective strategies: (1) bulky peripheral side groups; (2) “self‐doping” configuration induced by dual conformation; (3) highly ordered horizontal orientations. Nondoped organic light‐emitting diodes (OLEDs), using the two new emitters deliver 100% exciton utilization, record‐high maximum external quantum efficiencies of over 30%, and ultralow efficiency roll‐off for the first time.

Excessive alcohol consumption provides risk to cardiomyopathy with unknown mechanisms. Resveratrol, a plant polyphenol, is widely reported for its cardiovascular benefits, while its effect on alcohol-induced impairments in cardiomyocytes largely remains unknown. Effects of resveratrol on the cardiomyocytes under ethanol insult were studied in vitro. Ethanol exposure in mouse neonatal cardiomyocytes increased cell death and induced a specific loss of tight junction protein, connexin 43. In spite of adverse effects at higher concentrations, resveratrol at 10 μM improved cell viability of cardiomyocytes in the presence of a deleterious dose of ethanol. Importantly, the co-treatment of resveratrol with ethanol exhibited the restoration of connexin 43 protein. Further assays showed that these effects were likely associated with the antioxidative actions of resveratrol, and correlated with the alleviation of MAP kinase activation in cultured cardiomyocytes in response to ethanol. Our data suggests a novel mechanism of cardiomyocyte cell loss under ethanol exposure and provides new evidence of protective effects of resveratrol in the cardiomyocytes.

Inorganic polymer material is a new green energy-saving building material which has a broad development prospect. It has been a hot engineering research issue. In this paper, inorganic polymer concrete is made by using fly ash, mineral powder and alkaline activator. Its basic mechanical properties are studied by the cube compressive strength test, the drying-wetting cycle test and flexural strength test and compared with the ordinary concrete in the same sand ratio. The compressive strength of inorganic polymer concrete specimen with mineral powder in early days is much greater than the same level of ordinary concrete. Without mineral powder, its compressive strength has developed rapidly in the early days, but it become very slower in the later days. Furthermore, its ultimate compressive strength is less than the same level of ordinary concrete. After the drying-wetting cycles, the compressive strength of the inorganic polymer concrete specimen is lower than that of the standard conservation. The reduction rate with mineral powder is smaller. The flexural failure characteristics of inorganic polymer concrete specimen are the same with ordinary concrete. However, its bending strength is lower than the same level of ordinary concrete specimen. Research results provide valuable experimental data for the engineering application of inorganic polymer concrete.

Organic light-emitting diode (OLED) technology is promising for ultrahigh-definition displays and other applications, but further improvements in efficiency and colour purity are desired. Here, we designed and synthesized an ultrapure green emitter called DBTN-2, which is organoboron based and features a highly distorted fused π-conjugated molecular design. This design concept substantially reduces the relaxation energy between the geometries of the excited and ground states, leading to a full-width at half-maximum emission of only 20 nm. Furthermore, the different excitation characters of the singlet and triplet states enhance the spin–orbit couplings leading to highly efficient operation. The introduction of the multiple carbazole moieties gives rise to a charge-resonance-type excitation feature of the triplet states, thus resulting in a high density of the triplet states and a rate of reverse intersystem crossing (kRISC) as fast as 1.7 × 105 s−1. An ultrapure green OLED exploiting DBTN-2 as an emitter without optimized cavity effects and colour filters operated with Commission Internationale de l’Eclairage coordinates of (0.19, 0.74), satisfying the requirement for a commercial green OLED display. Moreover, in combination with a photoluminescence quantum yield of near 100% and a strong horizontal dipole orientation in the doped film, an excellent external quantum efficiency of 35.2% with suppressed efficiency roll-off is simultaneously obtained.An organoboron-emitter, DBTN-2, yields a green organic light-emitting diode with ultrapure colour and high efficiency.

The stress behavior of the reinforced inorganic polymer concrete(IPC) beam was discussed, included the load-deflection curve, craze load and ultimate bearing capacity under the static load function through the method of the experimental study and the non-linear finite element analysis. Compared the data of the experiment with the results of the finite element analysis, it indicates that the reinforced IPC beam owns higher ductility ratio and better deformation capacity on the same loading condition. Meanwhile, the cracks of IPC beam develop more slowly than the normal ones, there were less and smaller cracks on IPC beam. The research results offer the theoretical and experimental references for engineering practice and design index of IPC.

Background： Tuberculosis （TB） remains a worldwide problem. Intestinal TB （ITB） constitutes a major public health problem in developing countries and has been associated with significant morbidity and mortality. The aim of this study was to characterize the clinical, radiological, endoscopic, and pathological features of ITB and to define the strategy for establishing the diagnosis. Methods： A retrospective study （from January 2000 to June 2015） was carried out in Peking Union Medical College Hospital and all hospitalized cases were diagnosed as ITB during the study period were included. The relevant clinical information, laboratory results, microbiological, and radiological investigations were recorded. Results： Of the 85 cases, 61 cases （71.8%） were ranged from 20 to 50 years. The ileocecal region was involved in about 83.5% （71/85） of patients. About 41.2% （35/85） of patients had co-existing extra ITB, especially active pulmonary TB. Abdominal pain （82.4%） was the most common presenting symptom followed by weight loss （72.9%） and fever （64.7%）. Both T-cell spot of TB test （T-SPOT.TB） and purified protein derivatives （PPD） tests were performed in 26 patients： 20 （76.9%） positive T-SPOT.TB and 13 （50.0%） positive PPD were detected, with a statistical significant difference （P- 0.046）. Twenty cases （23.5%） were histopathology and/or pathogen confirmed TB; 27 cases （31.8%） were diagnosed by clinical manifestation consistent with ITB and evidence of active extra ITB; 38 cases （44.7%） were diagnosed by good response to diagnostic anti-TB therapy. Conclusions： ITB is difficult to diagnose even with modem medical techniques due to its nonspecific clinical and laboratory features. At present, combination of clinical, endoscopic, radiological, and pathological features continues to be the key to the diagnosis of ITB.

Efficient utilization of triplet excitons is vital in organic optoelectronics. One important strategy for harvesting triplets is thermally activated delayed fluorescence (TADF). In most TADF materials, the first singlet (S1) and triplet (T1) excited states both show strong charge-transfer (CT) character to reduce their energetic gap (EST); however, the negative consequence is small spin-orbit coupling and broad fluorescence emission width. To overcome this trade-off, our present work developed a novel strategy, i.e., intermolecular pi-pi-packing-induced (pi3) TADF, named pi3TADF. Distinct from the previously reported TADF systems, the excited states of our intermolecular pi3TADF systems show weak CT-excitation character. Our designed coplanar molecules based on a 1,5,9-trioxo-13-azatriangulene core show low photoluminescent quantum yields (PLQYs) in dilute solutions while their PLQYs in solid films reach ~ 100%. Their face-to-face pipi packings lead to the hybridization of intermolecular CT and localized pi-pi* excitations as well as electronic delocalization in the S1 states, while their T1 states show little changes. Consequently, with a dense manifold of the triplet states, the EST is significantly reduced while the large spin-orbit couplings are induced, thus leading to efficient TADF and significantly enhanced PLQYs in films. Organic light-emitting diodes exploiting the intermolecular pi3TADF systems as emitters show simultaneously high maximum external quantum efficiencies (e.g., over 30%) and narrow emission spectral widths (e.g., 44 nm). Our present work not only develops a new strategy, i.e., pi3TADF, for efficient TADF but also provides an in-depth understanding of its photophysical mechanism, thus opening a new approach for designing novel and efficient TADF materials.