Deep learning-based diagnosis of disease activity in patients with Graves' orbitopathy using orbital SPECT/CT.

PURPOSE: Orbital [99mTc]TcDTPA orbital single-photon emission computed tomography (SPECT)/CT is an important method for assessing inflammatory activity in patients with Graves' orbitopathy (GO). However, interpreting the results requires substantial physician workload. We aim to propose an automated method called GO-Net to detect inflammatory activity in patients with GO. MATERIALS AND METHODS: GO-Net had two stages: (1) a semantic V-Net segmentation network (SV-Net) that extracts extraocular muscles (EOMs) in orbital CT images and (2) a convolutional neural network (CNN) that uses SPECT/CT images and the segmentation results to classify inflammatory activity. A total of 956 eyes from 478 patients with GO (active: 475; inactive: 481) at Xiangya Hospital of Central South University were investigated. For the segmentation task, five-fold cross-validation with 194 eyes was used for training and internal validation. For the classification task, 80% of the eye data were used for training and internal fivefold cross-validation, and the remaining 20% of the eye data were used for testing. The EOM regions of interest (ROIs) were manually drawn by two readers and reviewed by an experienced physician as ground truth for segmentation GO activity was diagnosed according to clinical activity scores (CASs) and the SPECT/CT images. Furthermore, results are interpreted and visualized using gradient-weighted class activation mapping (Grad-CAM). RESULTS: The GO-Net model combining CT, SPECT, and EOM masks achieved a sensitivity of 84.63%, a specificity of 83.87%, and an area under the receiver operating curve (AUC) of 0.89 (p < 0.01) on the test set for distinguishing active and inactive GO. Compared with the CT-only model, the GO-Net model showed superior diagnostic performance. Moreover, Grad-CAM demonstrated that the GO-Net model placed focus on the GO-active regions. For EOM segmentation, our segmentation model achieved a mean intersection over union (IOU) of 0.82. CONCLUSION: The proposed Go-Net model accurately detected GO activity and has great potential in the diagnosis of GO.

Intramolecular Cyclization: A Convenient Strategy to Realize Efficient BT.2020 Blue Multi-Resonance Emitter for Organic Light-Emitting Diodes.

Rationally tuning the emission position and narrowing the full width at half-maximum (FWHM) of an emitter is of great importance for many applications. By synergistically improving rigidity, strengthening the resonant strength, inhibiting molecular bending and rocking, and destabilizing the HOMO energy level, a deep-blue emitter (CZ2CO) with a peak wavelength of 440 nm and an ultranarrow spectral FWHM of 16 nm (0.10 eV) was developed via intramolecular cyclization in a carbonyl/N resonant core (QAO). The dominant υ0-0 transition character of CZ2CO gives a Commission Internationale de I'Éclairage coordinates (CIE) of (0.144, 0.042), nicely complying with the BT.2020 standard. Moreover, a hyper-fluorescent device based on CZ2CO shows a high maximum external quantum efficiency (EQEmax ) of 25.6 % and maintains an EQE of 22.4 % at a practical brightness of 1000 cd m-2 .

Photo-controllable Luminescence from Radicals Leading to Ratiometric Emission Switching via Dynamic Intermolecular Coupling.

The development of photoinduced luminescent radicals with dynamic emission color is still challenging. Herein we report a novel molecular radical system (TBIQ) that shows photo-controllable luminescence, leading to a wide range of ratiometric color changes via light excitation. The conjugated skeleton of TBIQ is decorated with steric-demanding tertiary butyl groups that enable appropriate intermolecular interaction to make dynamic intermolecular coupling possible for controllable behaviors. We reveal that the helicenic pseudo-planar conformation of TBIQ experiences a planarization process after light excitation, leading to more compactly stacked supermolecules and thus generating radicals via intermolecular charge transfer. The photo-controllable luminescent radical system is employed for a high-level information encryption application. This study may offer unique insight into molecular dynamic motion for optical manufacturing and broaden the scope of smart-responsive materials for advanced applications.

Efficient Pyrazolo[5,4-f]quinoxaline Functionalized Os(II) Based Emitter with an Electroluminescence Peak Maximum at 811†nm.

Upon fusing the pyrazinyl pyrazole entity in giving pyrazolo[3,4-f]quinoxaline chelate, the corresponding Os(II) based NIR emitter exhibited "invisible" and efficient electroluminescence with a peak maximum at 811 nm. A maximum external quantum efficiency of 0.97 % and a suppressed efficiency roll-off till a current density of 300 mA cm-2 was also exhibited.

Efficient Blue Electrophosphorescence and Hyperphosphorescence Generated by Bis-tridentate Iridium(III) Complexes.

Four blue-emissive iridium(III) complexes bearing a 3,3'-(1,3-phenylene)bis[1-isopropyl-6-(trifluoromethyl)-3H-imidazo[4,5-b]pyridin-2-ylidene]-based pincer chelate, which are derived from PXn·H3(PF6)2, where n = 1-4, and a cyclometalating chelate given from 9-[6-[5-(trifluoromethyl)-2λ2-pyrazol-3-yl]pyridin-2-yl]-9H-carbazole [(PzpyCz)H2], were successfully synthesized and employed as both an emissive dopant and a sensitizer in the fabrication of organic light-emitting diode (OLED) devices. These functional chelates around a IrIII atom occupied two mutually orthogonal coordination arrangements and adopted the so-called bis-tridentate architectures. Theoretical studies confirmed the dominance of the electronic transition by the pincer chelates, while the dianionic PzpyCz chelate was only acting as a spectator group. Phosphorescent OLED devices with [Ir(PX3)(PzpyCz)] (B3) as the dopant gave a maximum external quantum efficiency (EQE) of 21.93% and CIExy of (0.144, 0.157) and was subjected to only ∼10% of roll-off in efficiency at a high current density of 1000 cd m-2. Blue-emissive narrow-band hyperphosphorescence was also obtained using B3 as an assistant sensitizer and ν-DABNA as a terminal emitter, giving both an improved EQE of 26.17% and CIExy of (0.116, 0.144), confirming efficient Förster resonance energy transfer in this hyperdevice.

Stepwise Access of Emissive Ir(III) Complexes Bearing a Multi-Dentate Heteroaromatic Chelate: Fundamentals and Applications.

Three multi-dentate coordinated chelates LnH2 (n = 1, 2, and 3), comprising a linked 1-(pyridin-2-yl)ethylbenzene and one pyrazolyl pyridine unit and showing either tridentate or tetradentate coordination modes, are successfully designed and synthesized. Dinuclear Ir(III) complexes [Ir(κ4-Ln)(µ-Cl)]2 bearing tetradentate coordinated κ4-Ln chelate (2a, n = 1; 2b, n = 2; 2c, n = 3) were next obtained en route from the respective intermediate [Ir(κ3-LnH)Cl(µ-Cl)]2 bearing the tridentate coordinated κ3-LnH chelate (1a, n = 1; 1b, n = 2; 1c, n = 3). Next, mononuclear Ir(III) complexes Ir(κ4-Ln)(thd) (3a, n = 1; 3b, n = 2; 3c, n = 3) with the tetradentate chelate were obtained upon treatment of 2 with 2,2,6,6-tetramethyl-3,5-heptanedione (thd)H in the presence of K2CO3. Concurrently, methylation of 2c in the presence of MeI and nBu4NCl afforded tridentate Ir(κ3-L3HMe)Cl3 (4) and, next, can be converted to tetradentate Ir(κ4-L3Me)Cl2 (5) by further cyclometalation and HCl elimination in refluxing diethylene glycol monoethyl ether solution. The Ir(III) complexes 3a, 4, and 5 were unambiguously identified using spectroscopic methods, together with single-crystal X-ray structural analyses on Ir(III) derivatives 3a, 4, and 5. Their photophysical and ,electrochemical properties and device fabrication properties were also investigated and compared with results from theoretical studies.

Probing Electron Excitation Characters of Carboline-Based Bis-Tridentate Ir(III) Complexes.

In this work, we report a series of bis-tridentate Ir(III) metal complexes, comprising a dianionic pyrazole-pyridine-phenyl tridentate chelate and a monoanionic chelate bearing a peripheral carbene and carboline coordination fragment that is linked to the central phenyl group. All these Ir(III) complexes were synthesized with an efficient one-pot and two-step method, and their emission hue was fine-tuned by variation of the substituent at the central coordination entity (i.e., pyridinyl and phenyl group) of each of the tridentate chelates. Their photophysical and electrochemical properties, thermal stabilities and electroluminescence performances are examined and discussed comprehensively. The doped devices based on [Ir(cbF)(phyz1)] (Cb1) and [Ir(cbB)(phyz1)] (Cb4) give a maximum external quantum efficiency (current efficiency) of 16.6% (55.2 cd/A) and 13.9% (43.8 cd/A), respectively. The relatively high electroluminescence efficiencies indicate that bis-tridentate Ir(III) complexes are promising candidates for OLED applications.

Ternary Acceptor-Donor-Acceptor Asymmetrical Phenanthroimidazole Molecule for Highly Efficient Near-Ultraviolet Electroluminescence with External Quantum Efficiency (EQE) >4 .

A new ternary acceptor (A)-donor (D)-acceptor (A) asymmetrically twisted deep-blue emitting molecule, PPI-2BI, was synthesized by attaching two electrophilic benzimidazole (BI) units to the C2 and N1 positions of a phenanthroimidazole (PI) donor unit. Profiting from the enhanced D-A electronic coupling, the electron injecting and transporting abilities of the new triangle-shaped A-D-A molecule are considerably improved and the molecule shows high photoluminescence (PL) and electroluminescence (EL) efficiencies. By using PPI-2BI as a non-doped emitting layer (EML), the resulting organic light-emitting device exhibits emission with color coordinates of (0.158, 0.124) and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.63 %, 4.98 cd A-1 , and 4.82 lm W-1 , respectively. Additionally, a simple bilayer device using PPI-2BI as both the EML and the electron-transporting layer (ETL) also shows an EQE of 3.81 % with little changes to the color purity. Remarkably, a PPI-2BI-based doped device emits efficient near-ultraviolet EL with color coordinates of (0.154, 0.047) and an EQE of 4.12 %, which is comparable to that of the best reported near-UV emitting devices.

High-Performance Blue OLEDs Based on Phenanthroimidazole Emitters via Substitutions at the C6- and C9-Positions for Improving Exciton Utilization.

Donor-acceptor (D-A) molecular architecture has been shown to be an effective strategy for obtaining high-performance electroluminescent materials. In this work, two D-A molecules, Ph-BPA-BPI and Py-BPA-BPI, have been synthesized by attaching highly fluorescent phenanthrene or pyrene groups to the C6- and C9-positions of a locally excited-state emitting phenylamine-phenanthroimidazole moiety. Equipped with good physical and hybridized local and charge-transfer properties, both molecules show high performances as blue emitters in nondoped organic light-emitting devices (OLEDs). An OLED using Ph-BPA-BPI as the emitting layer exhibits deep-blue emission with CIE coordinates of (0.15, 0.08), and a maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 4.56 %, 3.60 cd A(-1) , and 3.66 lm W(-1) , respectively. On the other hand, a Py-BPA-BPI-based, sky-blue OLED delivers the best results among nondoped OLEDs with CIEy values of < 0.3 reported so far, for which a very low turn-on voltage of 2.15 V, CIE coordinates of (0.17, 0.29), and maximum CE, PE, and EQE values of 10.9 cd A(-1) , 10.5 lm W(-1) , and 5.64 %, were achieved, respectively. More importantly, both devices show little or even no efficiency roll-off and high singlet exciton-utilizing efficiencies of 36.2 % for Ph-BPA-BPI and 39.2 % for Py-BPA-BPI.

Stepwise Toward Pure Blue Organic Light-Emitting Diodes by Synergetically Locking and Shielding Carbonyl/Nitrogen-Based MR-TADF Emitters.

Deep-blue multi-resonance (MR) emitters with stable and narrow full-width-at-half-maximum (FWHM) are of great importance for widening the color gamut of organic light-emitting diodes (OLEDs). However, most planar MR emitters are vulnerable to intermolecular interactions from both the host and guest, causing spectral broadening and exciton quenching in thin films. Their emission in the solid state is environmentally sensitive, and the color purity is often inferior to that in solutions. Herein, a molecular design strategy is presented that simultaneously narrows the FWHM and suppresses intermolecular interactions by combining intramolecular locking and peripheral shielding within a carbonyl/nitrogen-based MR core. Intramolecularly locking carbonyl/nitrogen-based bears narrower emission of 2,10-dimethyl-12,12-diphenyl-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione in solution and further with peripheral-shielding groups, deep-blue emitter (12,12-diphenyl-2,10-bis(9-phenyl-9H-fluoren-9-yl)-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione, DPQAO-F) exhibits ultra-pure emission with narrow FWHM (c.a., 24 nm) with minimal variations (∆FWHM ≤ 3 nm) from solution to thin films over a wide doping range. An OLED based on DPQAO-F presents a maximum external quantum efficiency (EQEmax) of 19.9% and color index of (0.134, 0.118). Furthermore, the hyper-device of DPQAO-F exhibits a record-high EQEmax of 32.7% in the deep-blue region, representing the first example of carbonyl/nitrogen-based OLED that can concurrently achieve narrow bandwidth in the deep-blue region and a high electroluminescent efficiency surpassing 30%.

Photocurable liquid crystal hydrogels with different chargeability and tunable viscoelasticity based on chitin whiskers.

We develop a kind of photocurable liquid crystal hydrogels with bone extracellular matrix (ECM)-like liquid crystal state and viscoelasticity, as well as different chargeability. First, positively charged chitin whiskers (CHWs) and negatively charged maleic anhydride chitin whiskers (mCHWs) were prepared, which further self-assemble to form chiral nematic liquid crystals under ultrasonic treatment, respectively. Subsequently, poly (ethylene glycol) diacrylate (PEGDA) and photo initiator were added, and then two kinds of liquid crystal hydrogels with bone ECM-like viscoelasticity and different chargeability were prepared under ultraviolet (UV) irradiation. Benefiting from the bone ECM-like liquid crystal state and viscoelasticity, the prepared liquid crystal hydrogels exhibit remarkable cell affinity and osteogenic ability. Moreover, the liquid crystal hydrogel with negatively charged mCHWs is more favorable for cell adhesion, spreading and osteogenic differentiation than that with positively charged CHWs. This work provides a promising strategy to prepare the hydrogels with bone ECM-like liquid crystal properties and viscoelasticity for bone repair.

3D Printing Drug-Free Scaffold with Triple-Effect Combination Induced by Copper-Doped Layered Double Hydroxides for the Treatment of Bone Defects.

Tissue-engineered poly(l-lactide) (PLLA) scaffolds have been widely used to treat bone defects; however, poor biological activities have always been key challenges for its further application. To address this issue, introducing bioactive drugs or factors is the most commonly used method, but there are often many problems such as high cost, uncontrollable and monotonous drug activity, and poor bioavailability. Here, a drug-free 3D printing PLLA scaffold with a triple-effect combination induced by surface-modified copper-doped layered double hydroxides (Cu-LDHs) is proposed. In the early stage of scaffold implantation, Cu-LDHs exert a photothermal therapy (PTT) effect to generate high temperature to effectively prevent bacterial infection. In the later stage, Cu-LDHs can further have a mild hyperthermia (MHT) effect to stimulate angiogenesis and osteogenic differentiation, demonstrating excellent vascularization and osteogenic activity. More importantly, with the degradation of Cu-LDHs, the released Cu2+ and Mg2+ provide an ion microenvironment effect and further synergize with the MHT effect to stimulate angiogenesis and osteogenic differentiation, thus more effectively promoting the healing of bone tissue. This triple-effect combined scaffold exhibits outstanding antibacterial, osteogenic, and angiogenic activities, as well as the advantages of low cost, convenient procedure, and long-term efficacy, and is expected to provide a promising strategy for clinical repair of bone defects.

Drug-Loaded and Anisotropic Wood-Derived Hydrogel Periosteum with Super Antibacterial, Anti-Inflammatory, and Osteogenic Activities.

Current artificial periostea mainly focus on osteogenic activity but overlook structural and mechanical anisotropy, as well as the importance of antibacterial and anti-inflammatory properties. Here, inspired by the anisotropic structure of wood, the delignified wood (named white wood, WW) with a porous and highly oriented cellulose fiber skeleton was obtained, which was further filled with polyvinyl alcohol (PVA) hydrogel loaded with curcumin (Cur) and phytic acid (PA). The prepared wood-derived hydrogel composite membranes can not only exhibit an obvious anisotropic structure and good mechanical properties but also sustainably release loaded drugs to obtain long-term biological activities. Creatively, PA can effectively improve the bioavailability of Cur; more importantly, Cur and PA play an obvious synergistic effect in antibacterial, anti-inflammatory, and osteogenic activities. Compared with the wood-derived hydrogel composite membranes without drug loading, as well as loaded with Cur or PA only, these loaded with Cur and PA are significantly more conducive to inhibiting the growth of bacteria and inflammatory response and facilitating the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells. This kind of anisotropic wood-derived hydrogel composite membrane with fantastic antibacterial, anti-inflammatory, and osteogenic activities is expected to be ideal artificial periostea.

Transmission Risks of Mountain-Type Zoonotic Visceral Leishmaniasis - Six Endemic Provincial-Level Administrative Divisions, China, 2015-2020.

What is already known about this topic?: Mountain-type zoonotic visceral leishmaniasis (MT-ZVL) cases in China have increased significantly between 2015 and 2020. A total of 25 regions had re-emerged yielding 88 MT-ZVL indigenous cases, while the total number of visceral leishmaniasis cases declined. What is added by this report?: The transmission risk of MT-ZVL showed a trend of patchy dissemination centered on major endemic areas and medium-high risk occurrence areas of Phlebotomus chinensis with discrete foci. Multi-point re-emergence and local outbreaks of MT-ZVL were trending in historically endemic areas. What are the implications for public health practice?: Risk identification and early warnings of MT-ZVL are essential in formulating precise prevention and control strategies in China. More frequent monitoring, establishing a mechanism of joint prevention and control, and highlighting health education are recommended.

The Role of Balancing Carrier Transport in Realizing an Efficient Orange-Red Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diode.

Simultaneously realizing improved carrier mobility and good photoluminescence (PL) efficiency in red thermally activated delayed-fluorescence (TADF) emitters remains challenging but important. Herein, two isomeric orange-red TADF emitters, oPDM and pPDM, with the same basic donor-acceptor backbone but a pyrimidine (Pm) attachment at different positions are designed and synthesized. The two emitters show similarly good PL properties, including narrow singlet-triplet energy offsets (0.11 and 0.15 eV) and high photoluminescence quantum yields (ca. 100 and 88%) in doped films. An orange-red organic light-emitting diode (OLED) employing oPDM as an emitter achieves an almost twice as high maximum external quantum efficiency (28.2%) compared with that of a pPDM-based OLED. More balanced carrier-transporting properties are responsible for their contrasting device performances, and the position effect of the Pm substituent leads to significantly distinct molecular packing behaviors in the aggregate states and different carrier mobilities.

Severity detection of COVID-19 infection with machine learning of clinical records and CT images.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a deadly viral infection spreading rapidly around the world since its outbreak in 2019. In the worst case a patient's organ may fail leading to death. Therefore, early diagnosis is crucial to provide patients with adequate and effective treatment. OBJECTIVE: This paper aims to build machine learning prediction models to automatically diagnose COVID-19 severity with clinical and computed tomography (CT) radiomics features. METHOD: P-V-Net was used to segment the lung parenchyma and then radiomics was used to extract CT radiomics features from the segmented lung parenchyma regions. Over-sampling, under-sampling, and a combination of over- and under-sampling methods were used to solve the data imbalance problem. RandomForest was used to screen out the optimal number of features. Eight different machine learning classification algorithms were used to analyze the data. RESULTS: The experimental results showed that the COVID-19 mild-severe prediction model trained with clinical and CT radiomics features had the best prediction results. The accuracy of the GBDT classifier was 0.931, the ROUAUC 0.942, and the AUCPRC 0.694, which indicated it was better than other classifiers. CONCLUSION: This study can help clinicians identify patients at risk of severe COVID-19 deterioration early on and provide some treatment for these patients as soon as possible. It can also assist physicians in prognostic efficacy assessment and decision making.

Deep-Blue OLEDs with Rec.2020 Blue Gamut Compliance and EQE Over 22% Achieved by Conformation Engineering.

To achieve high-efficiency deep-blue electroluminescence satisfying Rec.2020 standard blue gamut, two thermally activated delayed fluorescent (TADF) emitters are developed: 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasiline (TDBA-PAS) and 10-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-9,9-diphenyl-9,10-dihydroacridine (TDBA-DPAC). Inheriting from their parented organoboron multi-resonance core, both emitters show very promising deep-blue emissions with relatively narrow full width at half-maximum (FWHM, ≈50 nm in solution), high photoluminescence quantum yield (up to 92.3%), and short emission lifetime (≤2.49 µs) with fast reverse intersystem crossing (>106 s-1 ) in doped films. More importantly, replacing the spiro-centered sp3 C atom (TDBA-DPAC) with the larger-radius sp3 Si atom (TDBA-PAS), enhanced conformational heterogeneities in bulky-group-shielded TADF molecules are observed in solution, doped film, and device. Consequently, OLEDs based on TDBA-PAS retain high maximum external quantum efficiencies ≈20% with suppressed efficiency roll-off and color index close to Rec.2020 blue gamut over a wide doping range of 10-50 wt%. This study highlights a new strategy to restrain spectral broadening and redshifting and efficiency roll-off in the design of deep-blue TADF emitters.

Assessment on the Diagnostic Capacity for Parasitic Diseases of Health Facilities - China, 2019.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Morbidity and prevalence of several major parasitic diseases have been declining in China. To reduce the disease burden of parasitic diseases and protect public health security, conducting accurate diagnoses following timely treatment is important. WHAT IS ADDED BY THIS REPORT?: In the national competition held in 2019, the overall accuracy rates of participants for theoretical knowledge and slides interpretation for parasitic diseases were 80.44% and 66.87%, respectively. Significant differences in the accuracy rates of detecting schistosomiasis or malaria existed between endemic areas and non-endemic areas, respectively. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: The study results will help policymakers and health managers to identify the gaps in parasitic diseases, help to strengthen diagnostic capacity, and improve quality of control programs.

Two-Channel Space Charge Transfer-Induced Thermally Activated Delayed Fluorescent Materials for Efficient OLEDs with Low Efficiency Roll-Off.

Enhancing the reverse intersystem crossing (RISC) process of thermally activated delayed fluorescent (TADF) emitters is an effective approach to realize efficient organic light-emitting diodes (OLEDs) with low efficiency roll-off. In this work, we designed two novel TADF emitters, SAT-DAC and SATX-DAC, via a spiro architecture. Efficient maximum external quantum efficiencies (EQEs) of 22.6 and 20.9% with reduced efficiency roll-off (EQEs of 17.9 and 17.0% at 1000 cd m-2) were achieved via a "two-RISC-channel" strategy. X-ray diffraction shows close donor (D)/acceptor (A) spacing and suitable D/A orientation in crystals of the two emitters favoring both intra- and intermolecular through-space charge transfer (TSCT) processes. Transient photoluminescence decay measurements show that both emitters have two RISC channels leading to kISCT exceeding 106 s-1. These results suggest that the "two-RISC-channel" design can be a novel approach for enhancing performance of TADF emitters, in particular at high excitation densities.

Top-emitting thermally activated delayed fluorescence organic light-emitting devices with weak light-matter coupling.

Resonance interaction between a molecular transition and a confined electromagnetic field can lead to weak or strong light-matter coupling. Considering the substantial exciton-phonon coupling in thermally activated delayed fluorescence (TADF) materials, it is thus interesting to explore whether weak light-matter coupling can be used to redistribute optical density of states and to change the rate of radiative decay. Here, we demonstrate that the emission distribution of TADF emitters can be reshaped and narrowed in a top-emitting organic light-emitting device (OLED) with a weakly coupled microcavity. The Purcell effect of weak microcavity is found to be different for TADF emitters with different molecular orientations. We demonstrate that radiative rates of the TADF emitters with vertical orientation can be substantial increased in weakly coupled organic microcavity. These observations can enhance external quantum efficiencies, reduce efficiency roll-off, and improve color-purities of TADF OLEDs, especially for emitters without highly horizontal orientation.