The monolayer transition metal dichalcogenides have recently attracted much attention owing to their potential in valleytronics, flexible and low-power electronics, and optoelectronic devices. Recent ...reports have demonstrated the growth of large-size two-dimensional MoS2 layers by the sulfurization of molybdenum oxides. However, the growth of a transition metal selenide monolayer has still been a challenge. Here we report that the introduction of hydrogen in the reaction chamber helps to activate the selenization of WO3, where large-size WSe2 monolayer flakes or thin films can be successfully grown. The top-gated field-effect transistors based on WSe2 monolayers using ionic gels as the dielectrics exhibit ambipolar characteristics, where the hole and electron mobility values are up to 90 and 7 cm2/Vs, respectively. These films can be transferred onto arbitrary substrates, which may inspire research efforts to explore their properties and applications. The resistor-loaded inverter based on a WSe2 film, with a gain of ∼13, further demonstrates its applicability for logic-circuit integrations.
Transition‐metal‐catalyzed difluoroalkylation of aromatics remains challenging despite the importance of difluoroalkylated arenes in medicinal chemistry. Herein, the first successful example of ...nickel‐catalyzed difluoroalkylation of aryl boronic acids is described. The reaction allows access to a variety of functionalized difluoromethyl bromides and chlorides, and paves the way to highly cost‐efficient synthesis of a wide range of difluoroalkylated arenes. The notable features of this protocol are its high generality, excellent functional‐group compatibility, low‐cost nickel‐catalyst, and practicality for gram‐scale production, thus providing a facile method for applications in drug discovery and development.
Simple and easy: The first example of a nickel‐catalyzed difluoroalkylation of aryl boronic acids with functionalized difluoromethyl bromides and chlorides has been developed. This cross‐coupling process features a broad substrate scope, a cheap catalyst, and excellent functional‐group compatibility.
Dispersion engineering is always the important topic in the field of artificial periodic structures. In particular, topology optimization of composite structures with expected bandgaps plays a key ...role. However, most reported studies focused on topology optimization for bulk waves, and the optimization for surface wave bandgaps (SWBGs) is still missing. In this paper, we develop a topology optimization framework based on the genetic algorithm and finite element method to design periodic barriers embedded in semi-infinite space for reducing surface waves on demand. The objective functions for SWBGs are proposed based on the energy distribution properties of surface waves. The numerical results show that the optimization framework has stable convergence for this problem and is effective to optimize SWBGs. Considering large SWBGs and low filling fraction of solids, we investigate single- and multi-objective optimizations, respectively, and obtain novel wave barriers with good performance. The beneficial configuration features and mechanism of broadband SWBGs from the optimized results are explored. The results indicate that for the first-order SWBG, most optimized structures consist of a main scatterer at the center and some subsidiary scatterers near the surface. The rigid body resonance of the main scatterer determines the lower edge of SWBG, and the subsidiary scatterers can regulate the upper edge. Higher-order SWBGs are generated from the interaction of multiple scatterers, whose relative distance has a great influence on the position of SWBGs. The optimized structures can make the surface waves propagate far away from the surface within the frequencies of bandgaps, leading to a strong attenuation of surface vibration. In practice, our topological optimization framework is promising in designing high-performance surface wave devices and novel isolating structures for earthquake or environmental vibration in civil engineering.
Background and Aims
Hepatic ischemia‐reperfusion (I/R) injury, which mainly involves inflammatory responses and apoptosis, is a common cause of organ dysfunction in liver transplantation (LT). As a ...critical mediator of inflammation and apoptosis in various cell types, the role of tripartite motif‐containing (TRIM) 27 in hepatic I/R injury remains worthy of study.
Approach and Results
This study systemically evaluated the putative role of TRIM27/transforming growth factor β–activated kinase 1 (TAK1)/JNK (c‐Jun N‐terminal kinase)/p38 signaling in hepatic I/R injury. TRIM27 expression was significantly down‐regulated in liver tissue from LT patients, mice subjected to hepatic I/R surgery, and hepatocytes challenged by hypoxia/reoxygenation (H/R) treatment. Subsequently, using global Trim27 knockout mice (Trim27‐KO mice) and hepatocyte‐specific Trim27 transgenic mice (Trim27‐HTG mice), TRIM27 functions to ameliorate liver damage, reduce the inflammatory response, and prevent cell apoptosis. In parallel in vitro studies, activating TRIM27 also prevented H/R‐induced hepatocyte inflammation and apoptosis. Mechanistically, TRIM27 constitutively interacted with the critical components, TAK1 and TAK1 binding protein 2/3 (TAB2/3), and promoted the degradation of TAB2/3, leading to inactivation of TAK1 and the subsequent suppression of downstream JNK/p38 signaling.
Conclusions
TRIM27 is a key regulator of hepatic I/R injury by mediating the degradation of TAB2/3 and suppression of downstream TAK1‐JNK/p38 signaling. TRIM27 may be a promising approach to protect the liver against I/R‐mediated hepatocellular damage in transplant recipients.
Abstract
Monolayer transition metal dichalcogenides, such as MoS
2
and WSe
2
, have been known as direct gap semiconductors and emerged as new optically active materials for novel device ...applications. Here we reexamine their direct gap properties by investigating the strain effects on the photoluminescence of monolayer MoS
2
and WSe
2
. Instead of applying stress, we investigate the strain effects by imaging the direct exciton populations in monolayer WSe
2
–MoS
2
and MoSe
2
–WSe
2
lateral heterojunctions with inherent strain inhomogeneity. We find that unstrained monolayer WSe
2
is actually an indirect gap material, as manifested in the observed photoluminescence intensity–energy correlation, from which the difference between the direct and indirect optical gaps can be extracted by analyzing the exciton thermal populations. Our findings combined with the estimated exciton binding energy further indicate that monolayer WSe
2
exhibits an indirect quasiparticle gap, which has to be reconsidered in further studies for its fundamental properties and device applications.
Phosphorescent materials as block elements to build artwork incorporating the time and emission, enable them with spectacular lighting effects. In this work, enhanced phosphorescence of carbon ...nanodots (CNDs) is demonstrated via double confinement strategy, which silica and epoxy resin are used as the first and the second order confinement layer. The multi‐confined CNDs show an enhanced phosphorescence quantum yield up to 16.4%, with enduring emission lifetime up to 1.44 s. Delicately, the plasticity of the epoxy resin enables them easily to be designed for 3D artworks with long emission lifetimes in different shapes. The efficient and eco‐friendly phosphorescent CNDs may arouse intense interest both in the academic community and markets.
Enhanced phosphorescence of carbon nanodots (CNDs) is demonstrated via double confinement strategy, the plasticity of the epoxy resin enables them easily to be designed for 3D artworks with long emission lifetimes in different shapes.
Forrestiacids A (1) and B (2) are a novel class of 4+2 type pentaterpenoids derived from a rearranged lanostane moiety (dienophile) and an abietane unit (diene). These unprecedented molecules were ...isolated using guidance by molecular ion networking (MoIN) from Pseudotsuga forrestii, an endangered member of the Asian Douglas Fir Family. The intermolecular hetero‐Diels–Alder adducts feature an unusual bicyclo2.2.2octene ring system. Their structures were elucidated by spectroscopic analysis, GIAO NMR calculations and DP4+ probability analyses, electronic circular dichroism calculations, and X‐ray diffraction analysis. This unique addition to the pentaterpene family represents the largest and the most complex molecule successfully assigned using computational approaches to predict accurately chemical shift values. Compounds 1 and 2 exhibited potent inhibitory activities (IC50s <5 μM) of ATP‐citrate lyase (ACL), a new drug target for the treatment of glycolipid metabolic disorders including hyperlipidemia. Validating this activity 1 effectively attenuated the de novo lipogenesis in HepG2 cells. These findings provide a new chemical class for developing potential therapeutic agents for ACL‐related diseases with strong links to traditional medicines.
Forrestiacids A (1) and B (2), comprising a rearranged spiro‐lanostane unit fused with an abietene by a Diels–Alder cycloaddition, represent a novel class of pentaterpenoids obtained from Pseudotsuga forrestii. Chemical computations demonstrate to be an effective strategy in the structure elucidation of complex molecules. Both 1 and 2 showed potent ACL inhibitory effects, and 1 even significantly attenuated the de novo lipogenesis in HepG2 cells.
Acute infection, if not kept in check, can lead to systemic inflammatory responses in the brain. Here, we show that within 2 hr of systemic inflammation, PDGFRβ mural cells of blood vessels rapidly ...secrete chemokine CCL2, which in turn increases total neuronal excitability by promoting excitatory synaptic transmission in glutamatergic neurons of multiple brain regions. By single-cell RNA sequencing, we identified Col1a1 and Rgs5 subgroups of PDGFRβ cells as the main source of CCL2. Lipopolysaccharide (LPS)- or Poly(I:C)-treated pericyte culture medium induced similar effects in a CCL2-dependent manner. Importantly, in Pdgfrb-Cre;Ccl2fl/fl mice, LPS-induced increase in excitatory synaptic transmission was significantly attenuated. These results demonstrate in vivo that PDGFRβ cells function as initial sensors of external insults by secreting CCL2, which relays the signal to the central nervous system. Through their gateway position in the brain, PDGFRβ cells are ideally positioned to respond rapidly to environmental changes and to coordinate responses.
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•PDGFRβ cells function as initial sensors of systemic inflammation in the brain•PDGFRβ cells relay the infection signal to neurons by secreting chemokine CCL2•Col1a1 and Rgs5 subgroups of PDGFRβ cells are sources of Ccl2 during early infection•PDGFRβ-specific Ccl2 knockout blocked LPS-induced increase in synaptic transmission
Yu and colleagues identified Rgs5 and Col1a1 subgroups of PDGFRβ cells as early responders to neuroinflammation. These cells rapidly synthesize and release the chemokine CCL2, which in term elevates neuronal excitability and excitatory synaptic transmission in multiple neuronal types.
A photo‐induced three‐component coupling reaction of quinoxalinones with unactivated alkenes and azidobenziodoxolone (ABX, Zhdankin reagent) was developed. The protocol provides an efficient approach ...for the synthesis of various bioactive organoazides with quinoxalinone scaffold in moderate to good yields under mild conditions. This reaction is environmentally friendly avoiding the use of expensive transition‐metal photocatalysts and stoichiometric oxidants.
A photo‐induced three‐component coupling reaction of quinoxalinones with unactivated alkenes and ABX was developed, providing access to a variety of bioactive organoazides with quinoxalinone scaffold in good yields and excellent regioselectivities.
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