Developing red thermally activated delayed fluorescence (TADF) emitters, attainable for both high‐efficient red organic light‐emitting diodes (OLEDs) and non‐doped deep red/near‐infrared (NIR) OLEDs, ...is challenging. Now, two red emitters, BPPZ‐PXZ and mDPBPZ‐PXZ, with twisted donor–acceptor structures were designed and synthesized to study molecular design strategies of high‐efficiency red TADF emitters. BPPZ‐PXZ employs the strictest molecular restrictions to suppress energy loss and realizes red emission with a photoluminescence quantum yield (ΦPL) of 100±0.8 % and external quantum efficiency (EQE) of 25.2 % in a doped OLED. Its non‐doped OLED has an EQE of 2.5 % owing to unavoidable intermolecular π–π interactions. mDPBPZ‐PXZ releases two pyridine substituents from its fused acceptor moiety. Although mDPBPZ‐PXZ realizes a lower EQE of 21.7 % in the doped OLED, its non‐doped device shows a superior EQE of 5.2 % with a deep red/NIR emission at peak of 680 nm.
Two red emitters, BPPZ‐PXZ and mDPBPZ‐PXZ, with twisted donor–acceptor structures were designed and synthesized to study molecular design strategies of high‐efficiency red TADF emitters. BPPZ‐PXZ employs the strictest molecular restrictions to suppress energy loss and realizes red emission with a photoluminescence quantum yield (ΦPL) of 100±0.8 % and external quantum efficiency (EQE) of 25.2 % in a doped OLED.
Lithium–sulfur (Li–S) batteries have been recognized as promising substitutes for current energy‐storage technologies owing to their exceptional advantage in energy density. The main challenge in ...developing highly efficient and long‐life Li–S batteries is simultaneously suppressing the shuttle effect and improving the redox kinetics. Polar host materials have desirable chemisorptive properties to localize the mobile polysulfide intermediates; however, the role of their electrical conductivity in the redox kinetics of subsequent electrochemical reactions is not fully understood. Conductive polar titanium carbides (TiC) are shown to increase the intrinsic activity towards liquid–liquid polysulfide interconversion and liquid–solid precipitation of lithium sulfides more than non‐polar carbon and semiconducting titanium dioxides. The enhanced electrochemical kinetics on a polar conductor guided the design of novel hybrid host materials of TiC nanoparticles grown within a porous graphene framework (TiC@G). With a high sulfur loading of 3.5 mg cm−2, the TiC@G/sulfur composite cathode exhibited a substantially enhanced electrochemical performance.
Li–S batteries: The electrochemical reaction kinetics of reversible polysulfide interconversion and Li2S nucleation/precipitation are substantially enhanced on the conductive and polar surface of titanium carbide, guiding the design of advanced host materials towards high‐energy and stable Li–S batteries.
Described herein is the first intermolecular σ‐bond exchange reaction between the C−C bond of cyclopropenones and C−Si bond of (benzo)silacyclobutanes and it proceeds smoothly by treatment with ...either 1 mol % of a palladium or 2 mol % of a nickel catalyst. This reaction constitutes an unprecedented route for the synthesis of various sila(benzo)suberones. And it is also the first example of a σ‐bond exchange reaction involving cyclopropenones.
The exchange: Described is the first intermolecular σ‐bond cross‐exchange reaction between the C−C bond of cyclopropenones and the C−Si bond of (benzo)silacyclobutanes. The reaction constitutes the first catalytic method for the synthesis of a variety of sila(benzo)suberones. cod=1,5‐cyclooctadiene.
A cooperative interface constructed by “lithiophilic” nitrogen‐doped graphene frameworks and “sulfiphilic” nickel–iron layered double hydroxides (LDH@NG) is proposed to synergistically afford ...bifunctional Li and S binding to polysulfides, suppression of polysulfide shuttles, and electrocatalytic activity toward formation of lithium sulfides for high‐performance lithium–sulfur batteries. LDH@NG enables high rate capability, long lifespan, and efficient stabilization of both sulfur and lithium electrodes.
Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that regulates the cellular defense against toxic and oxidative insults through the expression of genes involved in ...oxidative stress response and drug detoxification. NRF2 activation renders cells resistant to chemical carcinogens and inflammatory challenges. In addition to antioxidant responses, NRF2 is involved in many other cellular processes, including metabolism and inflammation, and its functions are beyond the originally envisioned. NRF2 activity is tightly regulated through a complex transcriptional and post-translational network that enables it to orchestrate the cell's response and adaptation to various pathological stressors for the homeostasis maintenance. Elevated or decreased NRF2 activity by pharmacological and genetic manipulations of NRF2 activation is associated with many metabolism- or inflammation-related diseases. Emerging evidence shows that NRF2 lies at the center of a complex regulatory network and establishes NRF2 as a truly pleiotropic transcription factor. Here we summarize the complex regulatory network of NRF2 activity and its roles in metabolic reprogramming, unfolded protein response, proteostasis, autophagy, mitochondrial biogenesis, inflammation, and immunity.
•A comprehensive numerical study on the subcooled falling film heat transfer on a horizontal smooth tube is conducted.•The role of surface tension in the calculation of falling film heat transfer is ...discussed.•A heat transfer correlation considering a multitude of factors is developed.
The effects of film flow rate, heat flux, inlet liquid temperature, tube diameter and liquid distributor height on subcooled falling film heat transfer outside a horizontal smooth tube are numerically studied, and a heat transfer correlation based on the current data is developed. Comparisons between the predicted results and the published experimental data in the literature are also conducted. The calculation ranges are: film flow rate from 0.025 to 0.284 kg m−1 s−1, heat flux from 1.0 to 100 kW m−2, inlet liquid temperature from 2 to 104 °C, tube diameter from 6.35 to 50.8 mm and liquid distributor height from 3.0 to 50.8 mm. The results indicate that: (1) the numerical results of the local heat transfer coefficient are in good agreement with the experimental data in the literature; (2) the surface tension plays an important role in the calculations of heat transfer in two stagnation zones, (3) the heat transfer coefficient shows four distinct zones along with peripheral angle: stagnation zone, impingement zone, thermal layer development zone and departure zone; (4) the heat transfer coefficient increases with increase in film flow rate, tube diameter or liquid distributor height, while keeps constant with increasing heat flux; (5) the correlation predicts 92% of the total 141 calculated data with deviations within ±10%, and predicts 78% of 284 data available in literature with deviations within ±30%.
Fibre‐based materials have received tremendous attention due to their flexibility and wearability. Although great efforts have been devoted to achieve high‐performance fibres over the past several ...years, it is still challenging for multifunctional macroscopic fibres to satisfy versatile applications. 2D transition metal carbides/nitrides (MXenes) with intriguing physical/chemical properties have been explored in broad application, and may be able to reinforce synthetic fibres. Inspired by natural materials, for the first time, flexible smart fibres and textiles are fabricated using a 3D printing process with hybrid inks of TEMPO (2,2,6,6‐tetramethylpiperidine‐1‐oxylradi‐cal)‐mediated oxidized cellulose nanofibrils (TOCNFs) and Ti3C2 MXene. The hybrid inks display good rheological properties, which allow them to achieve accurate structures and be rapidly printed. TOCNFs/Ti3C2 in hybrid inks self‐assemble to fibres with an aligned structure in ethanol, mimicking the features of the natural structures of plant fibres. In contrast to conventional synthetic fibres with limited functions, smart TOCNFs/Ti3C2 fibres and textiles exhibit significant responsiveness to multiple external stimuli (electrical/photonic/mechanical). TOCNFs/Ti3C2 textiles with electromechanical performance can be processed into sensitive strain sensors. Such multifunctional smart fibres and textiles will be promising in diverse applications, including wearable heating textiles, human health monitoring, and human–machine interfaces.
Highly flexible and conductive smart fibres and textiles with integrated multifunctionality are fabricated by assembling cellulose nanofibrils and Ti3C2 MXene using a facile 3D printing process. The resultant smart fibres and textiles exhibit excellent responsiveness to multiple external stimuli (electrical/photonic/mechanical). The smart textile can also be processed into a sensitive strain sensor to achieve real‐time human motion recognition.
Background
Gaming behavior can induce cerebral changes that may be related to the neurobiological features of gaming disorder (GD). Additionally, individuals with higher levels of depression or ...impulsivity are more likely to experience GD. Therefore, the present pilot study explored potential neurobiological correlates of GD in the context of depression and impulsivity, after accounting for video gaming behavior.
Methods
Using resting‐state functional magnetic resonance imaging (fMRI), a cross‐sectional study was conducted with 35 highly involved male adult gamers to examine potential associations between GD severity and regional homogeneity (ReHo) in the entire brain. A mediation model was used to test the role of ReHo in the possible links between depression/impulsivity and GD severity.
Results
Individuals with greater GD severity showed increased ReHo in the right Heschl's gyrus and decreased ReHo in the right hippocampus (rHip). Furthermore, depression and impulsivity were negatively correlated with ReHo in the rHip, respectively. More importantly, ReHo in the rHip was found to mediate the associations between depression/impulsivity and GD.
Conclusions
These preliminary findings suggest that GD severity is related to ReHo in brain regions associated with learning/memory/mood and auditory function. Higher levels of depression or impulsivity may potentiate GD through the functional activity of the hippocampus. Our findings advance our understanding of the neurobiological differences behind GD symptoms in highly involved gamers.
35 highly involved male adult gamers participated in this pilot study. Hippocampal dysfunction related to the gaming disorder severity, depression and impulsivity. Hippocampal dysfunction may play a critical role in the development of gaming disorder.
Growing demand in intelligent wearable electronics raises an urgent requirement to develop deformable and durable power sources with high electrical performance. Here, a stretchable and ...shape‐adaptive triboelectric nanogenerator (TENG) based on a MXene liquid electrode is proposed. The open‐circuit voltage of an MXene‐based TENG reaches up to 300 V. The excellent fluidity and highly electronegativity of the MXene liquid electrode, gives the TENG long‐term reliability and stable electrical output regardless of diverse extreme deformations. With harvesting mechanical energy from hand tapping motion, the TENG in a self‐charging system can charge up capacitors to drive wearable electronics. Moreover, the TENG can be attached to both human skin and clothes as a human motion monitoring sensor, which can inspect the frequency and amplitude of various physiological movements. This work provides a new methodology for the construction of stretchable power sources and self‐powered sensors, which have potential applications in diverse fields such as robotics, kinesiology, and biomechanics.
A stretchable and shape‐adaptive triboelectric nanogenerator (TENG) based on a MXene liquid electrode is proposed. The TENG possesses outstanding output performance under various deformations, such as stretching, folding, and twisting. Furthermore, the flexible MXene‐based TENG, which can be used for biomechanical energy harvesting and self‐powered motion monitoring, has potential applications in soft robotics, green energy sources, human‐machine interactions, and wearable electronics.
•The effects of tube diameter, saturation temperature, film flow rate and heat flux on heat transfer are studied.•A threshold Reynolds number is proposed to delineate the test data into full wetting ...and partial dryout regimes.•The heat transfer correlations for R134a outside a single horizontal tube are developed.•Comparisons between the predicated results and the experimental data of other refrigerants in literature are conducted.
For the full wetting regime of falling film evaporation on a single horizontal smooth tube, the proposed correlation fits 94% of the data within ±20%.
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The falling film heat transfer of R134a outside a single horizontal smooth tube is experimentally investigated, and the effects of the tube diameter, saturation temperature, film flow rate and heat flux are studied. A threshold Reynolds number is proposed to delineate the test data into full wetting and partial dryout regimes. New correlations based on the present data and some data in literature are fitted for both regimes. The correlation for partial dryout regime fits 91% of the 153 data within ±20%, and the correlation for full wetting regime fits 94% of the 205 data within ±20%. The correlations have also been compared with previous measured data of other refrigerants available in literature. It is found that the predictions for partial dryout regime agree with most of the previous data with a deviation of ±30%.
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