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.
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.
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.
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.
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.
Previous studies have proved circFN1 is highly expressed in acute myeloid leukemia (AML) patients and AML cell lines. This study aims to investigate the impact of circFN1 on AML and its mechanism. ...Via real‐time quantitative PCR to detect circFN1, miR‐1294, ARHGEF10L expressions in clinical plasma samples and AML cell lines, AML cells were cultured in vitro and transfected with si‐circFN1, pcDNA3.1‐circFN1, and si‐ARHGEF10L, respectively, or co‐transfected pcDNA3.1‐circFN1 + miR‐1294 mimic and pcDNA3.1‐circFN1 + si‐ARHGEF10L. Using dual luciferase reporter experiment to detect the relationship between circFN1 and miR‐1294, as well as miR‐1294 and ARHGEF10L. CCK‐8 was used to detect cell proliferation, Transwell to cell invasion, TUNEL staining and flow cytometry to detect cell apoptosis, RT‐qPCR to circFN1 RNA, miR‐1294, and ARHGEF10L expression levels in HL‐60 cells, and western blot to ARHGEF10L protein expression level in HL‐60 cells. We found highly expressed circFN1 and ARHGEF10L, as well as low‐expressed miR‐1294 in AML patients and AML cell lines. In contrast to si‐NC group, si‐circFN1 group could signally inhibit HL‐60 cell proliferation and migration, but promote cell apoptosis; compared with mimic NC group, miR‐1294 mimic group could visually inhibit HL‐60 cell proliferation and migration, but promote cell apoptosis. miR‐1294 was the target of circFN1, and ARHGEF10L was the target of miR‐1294. Over‐expressing miR‐1294 or silencing ARHGEF10L could signally inhibit circFN1 promoting HL‐60 cell proliferation and migration and repressing cell apoptosis. circFN1 promotes proliferation and invasion of AML cell and represses cell apoptosis via regulating miR‐1294/ARHGEF10L axis, which provides new insight for molecular targeted‐treatment for AML.
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.
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.
All‐solid‐state lithium batteries (ASSLBs) have the potential to revolutionize battery systems for electric vehicles due to their benefits in safety, energy density, packaging, and operable ...temperature range. As the key component in ASSLBs, inorganic lithium‐ion‐based solid‐state electrolytes (SSEs) have attracted great interest, and advances in SSEs are vital to deliver the promise of ASSLBs. Herein, a survey of emerging SSEs is presented, and ion‐transport mechanisms are briefly discussed. Techniques for increasing the ionic conductivity of SSEs, including substitution and mechanical strain treatment, are highlighted. Recent advances in various classes of SSEs enabled by different preparation methods are described. Then, the issues of chemical stabilities, electrochemical compatibility, and the interfaces between electrodes and SSEs are focused on. A variety of research addressing these issues is outlined accordingly. Given their importance for next‐generation battery systems and transportation style, a perspective on the current challenges and opportunities is provided, and suggestions for future research directions for SSEs and ASSLBs are suggested.
Inorganic solid‐state electrolytes (SSEs) offer numerous advantages for the development of next‐generation batteries. The most promising advantages are the safety that benefits from the nonflammable nature of SSEs and the possibility of using a Li‐metal anode, which has highest capacity, lowest anodic potential, and is indispensable to the future success of high‐energy‐density Li–S batteries and Li–O2 battery systems.
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.
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