Biochemical evidence of pancreatic fistula alone has no clinical consequence and does not result in increased resource utilization. Increasing fistula grades have negative clinical and economic impacts on patients and their healthcare resources. These findings validate the ISGPF classification scheme for pancreatic fistula.

structural relaxation and vibronic coupling of the excited states. For pure organic materials, donor-acceptor typed thermally activated delayed fluorescence (TADF) emitters are able to realize 100% internal quantum efficiency via efficient reverse intersystem crossing (RISC) process, but the geometrical deformation between D and A units typically causes broad intramolecular charge-transfer emission with substantial Stokes shift in devices. [2] A promising molecular design strategy termed multiresonance TADF (MR-TADF) that fully addressed the aforementioned obstacle has been lately proposed by Hatakeyama et al. [3] This is made possible by atomic separation of frontier molecular orbitals (FMOs) via opposite resonance effect of electron-rich nitrogen and electron-deficient boron in a rigid molecular framework, which promises i) limited excited-state reorganization and minimized bonding/antibonding characteristics of FMOs, leading to compressed full width at half maximum (FWHM) of emission band; ii) adequate separation and overlap of the electron/hole wavefunctions to induce small singlet-triplet energy difference (ΔE ST ) and intense oscillating strength (f), leading to high luminescence efficiency. [4][5][6][7] An additional merit for most MR-TADF emitters is their tendency to adopt horizontal anisotropic orientation in vacuum-evaporated organic thin films, which would benefit light extraction from device and enhance efficiency. [5,8] For instance, by employing a state-of-the-art MR-TADF emitter ν-DABNA, maximum external quantum efficiency (EQE max ) up to 34.4% with high color purity (FWHM = 18 nm and Commission International de l'Éclairage (CIE) coordinates of (0.12, 0.11)) was realized in deep-blue OLED. [8,9] An important issue to be addressed for MR-TADF emitters is the severe aggregation-caused quenching (ACQ) and spectral broadening in solid state due to intense π-π interactions. [6,10,11] In a recent photophysical study, Monkman's group unveiled the strong prevalence for ν-DABNA to form less emissive aggregates/excimers even at extremely low doping concentrations, resulting in broadened linewidth and lower-than-expected device performances. [12] These findings offer a clear explanation to the fact that, though many MR-TADF emitters present narrowband photoluminescence (PL) emission with quantum Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters manifest great potential for organic light-emitting diodes (OLEDs) due to their high exciton-utilization efficiency and narrowband emission. Nonetheless, their tendency toward self-quenching caused by strong interchromophore interactions would induce doping sensitivity and deteriorate the device performances, and effective strategy to construct quenching-resistant emitters without sacrifycing color purity is still to be developed. By segregating the planar MR-TADF skeleton using two bulky carbazolyl units, herein a highly emissive molecule with enhanced quenching resistance is reported. The steric effect largely removes the formation of de...

Multi-resonance induced thermally activated delayed uorescent (MR-TADF) materials have shown great potential in high-e ciency and narrowband organic light-emitting diodes (OLEDs). However, obvious e ciency roll-off attributed to slow reverse intersystem crossing (RISC) process hinders MR-TADF materials from practical applications. Here, we report a heavy-atom incorporating emitter, namely BNSeSe, based on selenium-integrated boron-nitrogen skeleton, showing 100% photoluminescence quantum yield and the highest rate of RISC (k RISC ) of 2.0 × 10 6 s -1 among MR-TADF molecules. The corresponding OLEDs exhibit excellent external quantum e ciency (EQE) up to 36.8% and ultra-low roll-off character at high brightness (with very small roll-off values of 2.8% and 14.9% at 1000 cd m -2 and 10000 cd m -2 , respectively). Furthermore, the outstanding capability to harvest triplet excitons also enables BNSeSe to be a superior sensitizer for hyper uorescence (HF) device, which shows state-of-the-art performance with record high EQE of 40.5%, power e ciency (PE) beyond 200 lm W -1 and luminance close to 200000 cd m -2 . Full TextOrganic light-emitting diodes (OLEDs) with simultaneously high e ciency and narrowband emission become increasingly important for the demands on energy-saving and high-quality of displays. Thanks to the pioneer work by Hatakeyama et al., multi-resonance (MR) thermally activated delayed uorescent (TADF) emitters have emerged with the astonishing narrowband emission that could ful ll the requirements. 1,2 A high external quantum e ciency (EQE) up to 34% and electroluminescence (EL) with full width at half maximum (FWHM) of 18 nm demonstrated their great potential towards practical applications. 3 However, MR-TADF emitters usually possess long delay lifetime of several tens of microsecond, which usually leads to large e ciency roll-off at high brightness and thus impede their commercialization. [4][5][6][7][8][9][10]

A central question in Alzheimer's disease research is what role synaptic activity plays in the disease process. Synaptic activity has been shown to induce ␤-amyloid peptide release into the extracellular space, and extracellular ␤-amyloid has been shown to be toxic to synapses. We now provide evidence that the well established synaptotoxicity of extracellular ␤-amyloid requires ␥-secretase processing of amyloid precursor protein. Recent evidence supports an important role for intraneuronal ␤-amyloid in the pathogenesis of Alzheimer's disease. We show that synaptic activity reduces intraneuronal ␤-amyloid and protects against ␤-amyloid-related synaptic alterations. We demonstrate that synaptic activity promotes the transport of the amyloid precursor protein to synapses using live cell imaging, and that the protease neprilysin is involved in reduction of intraneuronal ␤-amyloid with synaptic activity.

Accumulation of ␤-amyloid (A␤) and loss of synapses are hallmarks of Alzheimer's disease (AD). How synaptic activity relates to A␤ accumulation and loss of synapses is a current topic of major interest. Synaptic activation promotes A␤ secretion, and chronic reduction of synaptic activity reduced A␤ plaques in an AD transgenic mouse model. This suggested beneficial effects of reducing synaptic activity in AD. We now show that reduced synaptic activity causes detrimental effects on synapses and memory despite reducing plaques using two different models of chronic synaptic inhibition: deafferentation of the barrel cortex and administration of benzodiazepine. An interval of prolonged synaptic inhibition exacerbated loss of synaptophysin compared with synaptically more active brain in AD transgenic but not wild-type mice. Furthermore, an interval of benzodiazepine treatment, followed by a washout period, exacerbated memory impairment in AD transgenic mice. Exacerbation of synaptic and behavioral abnormalities occurred in the setting of reduced A␤ plaques but elevated intraneuronal A␤ immunoreactivity. These data support beneficial effects of synaptic activation on A␤-related synaptic and behavioral impairment in AD.

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Multiresonance thermal activated delayed fluorescence (MR-TADF) materials with an efficient spin–flip transition between singlet and triplet excited states remain demanding. Herein, we report an MR-TADF compound (BN–Se) simultaneously possessing efficient (reverse) intersystem crossing (ISC/RISC), fast radiative decay, close-to-unity quantum yield, and narrowband emission by embedding a single selenium atom into a common 4,4′-diazaborin framework. Benefitting from the high RISC efficiency accelerated by the heavy-atom effect, organic light-emitting diodes (OLEDs) based on BN–Se manifest excellent performance with an external quantum efficiency of up to 32.6% and an ultralow efficiency roll-off of 1.3% at 1000 cd m–2. Furthermore, the high ISC efficiency and small inherent energy loss also render BN–Se a superior photosensitizer to realize the first example of visible (λex > 450 nm)-to-UV (λem < 350 nm) triplet–triplet annihilation upconversion, with a high efficiency (21.4%) and an extremely low threshold intensity (1.3 mW cm–2). This work not only aids in designing advanced pure organic molecules with fast exciton dynamics but also highlights the value of MR-TADF compounds beyond OLED applications.

light-emitting diodes (OLEDs) due to their low production-cost as well as the capability to harvest "dark" triplet excitons via a reverse intersystem crossing (RISC) mechanism. [1][2][3][4] Facilitating of RISC is made by reduction of the energy gap (ΔE ST ) between the lowest excited singlet and triplet (S 1 and T 1 ) states, typically achieved in twisted donor-acceptor (D-A) typed molecules with separated frontier molecular orbitals (FMOs) at the expense of low oscillator strength (f) and photoluminescence quantum yield (Φ PL ). [5][6][7][8] This contradiction undoubtedly sets an obstacle to obtain highly efficient emitter, and the large structural reorganization occurred in the excited state would cause broad emission spectra and increased non-radiative decay channels, eventually weakening the performances of corresponding devices. [9][10][11][12][13][14][15] Instead of the conventional D-A configured emitters, a unique category of multi-resonance TADF (MR-TADF) molecules based on fused polycyclic aromatics was lately proposed by Hatakeyama et al. to mitigate the aforementioned issues. [16][17][18][19][20][21][22] The complementary resonance effects of electrondeficient B and electron-rich N/O atoms within the framework separates the FMOs to induce short-range charge-transfer (SR-CT), concurrently offering a small ΔE ST and a high radiative decay rate (10 7 -10 8 s −1 ) from S 1 to ground (S 0 ) state. [17,23] The planar nature with high rigidity guaranteed narrow full width at half maximum (FWHM) emissions, and could also induce favorable horizontal dipole orientation of the emitters to boost optical out-coupling efficiency. [24] Thus far, the majority of the blue MR-TADF emitters were constructed from the basic motif DABNA (Scheme 1) due to synthetic feasibility and their decent quantum efficiencies. [25] Replacement of the diphenylamino subunits into carbazolyl-derived BN-CZ as a new core skeleton with bathochromic emission, which was adopted to realize full-color electroluminescence (EL) with high color purity and maximum external quantum efficiencies (EQE max s) above 20% by peripheral electronic modulation. [24,[26][27][28][29] Nonetheless, most MR-TADF devices encountered severe triplet-related efficiency loss at high luminance/current density stemmed from the intrinsic structural planarity and long-delayed lifetime, and relied on the involvement of sensitizing host to avoid triplet Multi-resonance thermally activated delayed fluorescence (MR-TADF) offers an exceptional solution for narrowband organic light-emitting diode devices in terms of color purity and luminescence efficiency, while the development of new MR skeleton remains an exigent task. It is hereby demonstrated that a simple modification of the B (boron)−N (nitrogen) framework by sp 3 -carbon insertion will significantly bathochromic shift the short-range charge-transfer emission, boost the reverse intersystem crossing process, and improve the device performances. The bis(acridan)phenylene-based skeleton developed in this contribution presen...