Simultaneously achieving a high photoluminescence quantum yield (PLQY), ultrashort exciton lifetime, and suppressed concentration quenching in thermally activated delayed fluorescence (TADF) ...materials is desirable yet challenging. Here, a novel acceptor–donor–acceptor type TADF emitter, namely, 2BO‐sQA, wherein two oxygen‐bridged triarylboron (BO) acceptors are arranged with cofacial alignment and positioned nearly orthogonal to the rigid dispirofluorene‐quinolinoacridine (sQA) donor is reported. This molecular design enables the compound to achieve highly efficient (PLQYs up to 99%) and short‐lived (nanosecond‐scale) blue TADF with effectively suppressed concentration quenching in films. Consequently, the doped organic light‐emitting diodes (OLEDs) base on 2BO‐sQA achieve exceptional electroluminescence performance across a broad range of doping concentrations, maintaining maximum external quantum efficiencies (EQEs) at over 30% for doping concentrations ranging from 10 to 70 wt%. Remarkably, the nondoped blue OLED achieves a record‐high maximum EQE of 26.6% with a small efficiency roll‐off of 14.0% at 1000 candelas per square meter. By using 2BO‐sQA as the sensitizer for the multiresonance TADF emitter ν‐DABNA, TADF‐sensitized fluorescence OLEDs achieve high‐efficiency deep‐blue emission. These results demonstrate the feasibility of this molecular design in developing TADF emitters with high efficiency, ultrashort exciton lifetime, and minimal concentration quenching.
A novel acceptor–donor–acceptor type molecular skeleton is designed to realize blue thermally activated delayed fluorescence with ultrahigh emission efficiencies (up to 99%), nanosecond exciton lifetimes, and effectively suppressed concentration quenching in films. The doped and nondoped organic light‐emitting diodes attain high external quantum efficiencies up to 32.0% and 26.6%, respectively.
Substantial efforts are underway to develop all‐solid‐state Li batteries (SSLiBs) toward high safety, high power density, and high energy density. Garnet‐structured solid‐state electrolyte exhibits ...great promise for SSLiBs owing to its high Li‐ion conductivity, wide potential window, and sufficient thermal/chemical stability. A major challenge of garnet is that the contact between the garnet and the Li‐metal anodes is poor due to the rigidity of the garnet, which leads to limited active sites and large interfacial resistance. This study proposes a new methodology for reducing the garnet/Li‐metal interfacial resistance by depositing a thin germanium (Ge) (20 nm) layer on garnet. By applying this approach, the garnet/Li‐metal interfacial resistance decreases from ≈900 to ≈115 Ω cm2 due to an alloying reaction between the Li metal and the Ge. In agreement with experiments, first‐principles calculation confirms the good stability and improved wetting at the interface between the lithiated Ge layer and garnet. In this way, this unique Ge modification technique enables a stable cycling performance of a full cell of lithium metal, garnet electrolyte, and LiFePO4 cathode at room temperature.
Owing to the rigidity of garnet‐structured solid‐state electrolyte, the contact between the garnet and a Li‐metal anode is poor, which leads to a large interfacial resistance. By depositing a thin germanium layer on the garnet, the interfacial resistance is greatly reduced due to the Li–Ge alloying reaction. Full cells using Li metal, Ge‐modified garnet, and a LiFePO4 cathode show stable cycling performance.
Terpenes are the largest class of small‐molecule natural products on earth, and the most abundant by mass. Here, we summarize recent developments in elucidating the structure and function of the ...proteins involved in their biosynthesis. There are six main building blocks or modules (α, β, γ, δ, ε, and ζ) that make up the structures of these enzymes: the αα and αδ head‐to‐tail trans‐prenyl transferases that produce trans‐isoprenoid diphosphates from C5 precursors; the ε head‐to‐head prenyl transferases that convert these diphosphates into the tri‐ and tetraterpene precursors of sterols, hopanoids, and carotenoids; the βγ di‐ and triterpene synthases; the ζ head‐to‐tail cis‐prenyl transferases that produce the cis‐isoprenoid diphosphates involved in bacterial cell wall biosynthesis; and finally the α, αβ, and αβγ terpene synthases that produce plant terpenes, with many of these modular enzymes having originated from ancestral α and β domain proteins. We also review progress in determining the structure and function of the two 4Fe‐4S reductases involved in formation of the C5 diphosphates in many bacteria, where again, highly modular structures are found.
Natural building blocks: Recent progress has been achieved in determining the structure, function, and inhibition of the enzymes responsible for the formation of terpenes and isoprenoids. Most of these enzymes contain combinations of α‐, β‐, γ‐, δ‐, ε‐, and/or ζ‐domain structures that in many cases are fused to form modular proteins. Gene fusion, exon loss, and recombination are thought to play major roles in the genesis of these enzymes.
This paper first derives the characteristics of radial electromagnetic force considering different types of current harmonics. By using two-dimensional fast Fourier transform, the force calculated by ...the finite element method is decomposed to obtain the frequencies of the force components in specific spatial order. Then, a multiphysics model for electromagnetic vibration and noise calculation is proposed. A modal test is implemented to validate the equivalent stator model and the nonuniform distribution of electromagnetic force acting on the teeth surface is taken into account through the nodal force transfer method. The calculated vibration and noise agree well with those obtained from experimental test. Finally, vibration and noise under different supply currents are investigated, and the variation patterns of the noise and vibration peaks are explained by the amplitude changes of the lowest spatial order force due to current harmonics. It is found that the influence of current harmonics on vibration and noise depends on their effect on the lowest spatial order force, and in order to figure out this effect, the phase angle, phase sequence, and frequency of current harmonics should all be considered.
Air pollution is a world public health problem. Particulate matter (PM), a mix of solid and liquid particles in the air, becomes an increasing concern in the social and economic development of China. ...For decades, epidemiological studies have confirmed the association between fine particle pollutants and respiratory diseases. It has been reported in different populations that increased fine particulate matter (PM2.5) concentrations cause elevated susceptibility to respiratory diseases, including acute respiratory distress, asthma, chronic obstructive pulmonary disease, and lung cancer. This review will discuss the pathophysiology of PM2.5 in respiratory diseases, which are helpful for the prevention of air pollution and treatment of respiratory tract inflammatory diseases.
The development of orange‐red/red thermally activated delayed fluorescence (TADF) materials with both high emission efficiencies and short lifetimes is highly desirable for electroluminescence (EL) ...applications, but remains a formidable challenge owing to the strict molecular design principles. Herein, two new orange‐red/red TADF emitters, namely AC‐PCNCF3 and TAC‐PCNCF3, composed of pyridine‐3,5‐dicarbonitrile‐derived electron‐acceptor (PCNCF3) and acridine electron‐donors (AC/TAC) are developed. These emitters in doped films exhibit excellent photophysical properties, including high photoluminescence quantum yields of up to 0.91, tiny singlet‐triplet energy gaps of 0.01 eV, and ultrashort TADF lifetimes of less than 1 µs. The TADF‐organic light‐emitting diodes employing the AC‐PCNCF3 as emitter achieve orange‐red and red EL with high external quantum efficiencies of up to 25.0% and nearly 20% at doping concentrations of 5 and 40 wt%, respectively, both accompanied by well‐suppressed efficiency roll‐offs. This work provides an efficient molecular design strategy for developing high‐performance red TADF materials.
In this work, orange‐red/red thermally activated delayed fluorescence materials achieve high photoluminescence quantum yields of up to 91% with ultrashort exciton lifetimes of less than 1 µs, demonstrating a successful balance between high efficiency and fast reverse intersystem crossing. Highly efficient organic light‐emitting diodes are realized with external quantum efficiencies of up to 25.0% and small efficiency roll‐offs.
Posttraumatic stress disorder (PTSD) is a psychiatric disorder that plagues trauma survivors. Evidence shows that brain‐derived neurotrophic factor (BDNF) may be involved in the occurrence and ...development of PTSD. Here we tried to demonstrate whether BDNF gene polymorphisms are correlated with neurocognitive function following PTSD in patients with hepatocellular carcinoma (HCC). This study included 102 patients with HCC complicated with PTSD, 146 HCC patients, and 152 healthy volunteers. Initially, we evaluated the neurocognitive function of the study subjects. Next, we measured BDNF G11757C and rs6265 polymorphisms by polymerase chain reaction‐restriction fragment length polymorphism. The correlation of BDNF polymorphisms and BDNF level with HCC complicated with PTSD was evaluated. The results revealed that HCC complicated with PTSD showed decreased serum BDNF level and Mini‐mental state examination (MMSE) score. Serum BDNF level of HCC and HCC complicated with PTSD was positively correlated with MMSE score. GA + AA allele and A allele of rs6265 increased the risk of PTSD among patients with HCC. GA and AA genotypes of rs6265 were correlated with the decreased MMSE score of HCC complicated with PTSD. Haplotype GA of rs6265 and G11757C increased the risk of PTSD for HCC, while haplotype CG decreased this risk. Lastly, the logistic regression analysis suggested that low BDNF level was a contributor to HCC complicated with PTSD, while GG genotype of rs6265 served as a protective factor. Collectively, this study defines the GG genotype of BDNF rs6265 polymorphism as a protector to HCC complicated with PTSD. In addition, these results provided a promising target for PTSD prevention in patients with HCC.
Collectively, this study defines the GG genotype of brain‐derived neurotrophic factor (BDNF) rs6265 polymorphism as a protector to hepatocellular carcinoma (HCC) complicated with posttraumatic stress disorder (PTSD). In addition, these results provided a promising target for PTSD prevention in patients with HCC.
Schematic presentation of humoral and cellular responses involved in bivalve defense mechanisms upon infection by micro-organisms. Blue indicates steps of phagocytosis and encapsulation. Step 1: ...Chemotaxis, attraction and migration. Step 2: Recognition and attachment of invading micro-organisms. These two steps involve the presence and the synthesis of lectins. Step 3: Internalization of micro-organisms within a phagosome. Step 4: Destruction of the micro-organism by oxygen dependent and oxygen independent microbicidal activities. These four steps constitute phagocytosis. However at Step 3′ when hemocytes failed to phagocytose the micro-organisms (possibly because they are too big for internalization), they encapsulate them and destroy them externally (Step 4′) with lysosomal enzymatic and ROS activities. Green indicates the various humoral factors such as antimicrobial peptides, lysosomal hydrolysases, protease inhibitors that also contribute to eliminate pathogenic micro-organisms. Purple symbolizes the invading micro-organisms. Display omitted
•Host defense mechanisms and humoral and cellular responses to Perkinsus spp. infection.•Perkinsus spp. metabolic biochemistry and virulence factors.•Physiological and immunological changes upon infection by Perkinsus spp.•Host–parasite interactions in variable and adverse environments.
This review assesses and examines the work conducted to date concerning host and parasite interactions between marine bivalve molluscs and protozoan parasites, belonging to Perkinsus species. The review focuses on two well-studied host–parasite interaction models: the two clam species, Ruditapes philippinarum and R. decussatus, and the parasite Perkinsus olseni, and the eastern oyster, Crassostrea virginica, and the parasite Perkinsus marinus. Cellular and humoral defense responses of the host in combating parasitic infection, the mechanisms (e.g., antioxidant enzymes, extracellular products) employed by the parasite in evading host defenses as well as the role of environmental factors in modulating the host–parasite interactions are described.
Enzymatic Synthesis of Variediene Analogs Liang, Lin‐Fu; Dickschat, Jeroen S.
Chemistry : a European journal,
March 10, 2022, Letnik:
28, Številka:
15
Journal Article
Recenzirano
Odprti dostop
Five analogs of dimethylallyl diphosphate (DMAPP) with additional or shifted Me groups were converted with isopentenyl diphosphate (IPP) and the fungal variediene synthase from Aspergillus ...brasiliensis (AbVS). These enzymatic reactions resulted in the formation of several new terpene analogs that were isolated and structurally characterised by NMR spectroscopy. Several DMAPP analogs showed a changed reactivity giving access to compounds with unusual skeletons. Their formation is mechanistically rationalised and the absolute configurations of all obtained compounds were determined through a stereoselective deuteration strategy, revealing absolute configurations that are analogous to that of the natural enzyme product variediene.
Five DMAPP analogs with additional carbon atoms or with changed methylation patterns were converted with IPP and the bifunctional variediene synthase from Aspergillus brasiliensis AbVS to yield diterpene analogs with unusual skeletons. The DMAPP analogs opened new reaction pathways through the stabilisation of cationic charges at alternative carbon atoms that are naturally not observed.
Li metal has the highest specific capacity (3860 mA h g
−1
) and the lowest electrochemical potential (− 3.04 V vs. SHE) of available metal anodes. Together with the high specific capacity of sulfur ...cathodes (1670 mA h g
−1
), Li metal–S batteries are a promising candidate to achieve high energy density batteries for electric vehicles and future industry. However, Li metal anodes suffer from corrosive reactions with electrolytes, a theoretically infinite volume change, and the growth of dendrites during electrochemical cycling. To realize the practical application of Li metal–S batteries, protective layers or artificial solid-electrolyte interphase (ASEI) layers have been applied to the surface of Li metal. These ASEI layers demonstrate capabilities to suppress the growth of dendrites and mitigate side reactions, which enhance the performance and safety of Li metal anodes in liquid-electrolyte systems, though there are still limitations and challenges. The development of solid-state electrolytes as artificial SEIs provides a promising route to suppress the issues of dendrite formation and the polysulfide “shuttle effect” in Li–S chemistry; however, the improvement in the interfacial compatibility and stability between the Li metal and the solid-state electrolyte is crucially needed. In this review, we summarize different types of ASEI layers used to protect Li metal, especially in Li–S batteries, with both liquid- and solid-electrolyte systems. We also briefly introduce the concept of anode protection of Mg metal and its application in Mg–S batteries. Perspectives regarding the further development and improvement of ASEI layers for Li metal and Mg metal are discussed.
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