Adversarial Attacks and Defenses for Semantic Communication in Vehicular Metaverses

For vehicular metaverses, one of the ultimate user-centric goals is to optimize the immersive experience and Quality of Service (QoS) for users on board. Semantic Communication (SemCom) has been introduced as a revolutionary paradigm that significantly eases communication resource pressure for vehicular metaverse applications to achieve this goal. SemCom enables high-quality and ultra-efficient vehicular communication, even with explosively increasing data traffic among vehicles. In this article, we propose a hierarchical SemCom-enabled vehicular metaverses framework consisting of the global metaverse, local metaverses, SemCom module, and resource pool. The global and local metaverses are brand-new concepts from the metaverse's distribution standpoint. Considering the QoS of users, this article explores the potential security vulnerabilities of the proposed framework. To that purpose, this study highlights a specific security risk to the framework's SemCom module and offers a viable defense solution, so encouraging community researchers to focus more on vehicular metaverse security. Finally, we provide an overview of the open issues of secure SemCom in the vehicular metaverses, notably pointing out potential future research directions

Mechanism of herpesvirus UL24 protein regulating viral immune escape and virulence

Herpesviruses have evolved a series of abilities involved in the process of host infection that are conducive to virus survival and adaptation to the host, such as immune escape, latent infection, and induction of programmed cell death for sustainable infection. The herpesvirus gene UL24 encodes a highly conserved core protein that plays an important role in effective viral infection. The UL24 protein can inhibit the innate immune response of the host by acting on multiple immune signaling pathways during virus infection, and it also plays a key role in the proliferation and pathogenicity of the virus in the later stage of infection. This article reviews the mechanism by which the UL24 protein mediates herpesvirus immune escape and its effects on viral proliferation and virulence by influencing syncytial formation, DNA damage and the cell cycle. Reviewing these studies will enhance our understanding of the pathogenesis of herpesvirus infection and provide evidence for new strategies to combat against viral infection

Research progress of lithium-ion batteries thick-electrode architectural design

To meet the requirements of high energy density and fast charge for energy storage systems and electric vehicles, the high-energy and high-power density lithium-ion batteries have attracted numerous attentions.Designing thick-electrode can significantly increase energy density and reduce cost, and is also compatible with various electrode materials, which makes it one of hottest researches for the development of high-energy density lithium-ion batteries.Thick electrodes usually suffer from poor mechanical properties and sluggish reaction kinetics. Therefore, it is very important to construct a thick electrode with good mechanical properties and fast transport network for lithium ion and electron.The electrochemical behavior and key scientific issues of thick electrodes were firstly analyzed in this review, the current strategies for constructing thick electrodes and their advantages were then introduced, and finally the design principles and the development direction of thick electrodes were pointed out

Stable Iso-osmabenzenes from a Formal [3+3] Cycloaddition Reaction of Metal Vinylidene with Alkynols

National Science Foundation of China[20872123, 20925208

Osmabenzenes from Osmacycles Containing an eta(2)-Coordinated Olefin

Treatment of HC CC(CH3)(OH)CH=CH2 with [OsCl2(PPh3)(3)] in dichloromethane yielded the eta(2)-olefin-coordinated osmacycle [Os{CH=C(PPh3)C(=CH2)-eta(2)-CH=CH2}Cl-2(PPh3)(2)] (9). Transform at ions of osmacycle 9 by treatment with benzonitrile under various conditions have been investigated. Reaction of 9 with excess benzonitrile at room temperature afforded the dicationic osmacycle [Os{CH=C(PPh3)C(=CH2)-eta(2)-CH=CH2}(PhCN)(2)(PPh3)(2)]Cl-2 (11) by ligand substitution, which reacted further to the intramolecularly coordinated eta(2)-allene complex [Os{CH=C(PPh3)C(CH3)=(eta(2)-C=CH2)}(PhCN)(2)(PPh3)(2)]Cl-2 (12). In contrast, heating a chloroform solution of 9 to the reflux temperature in the presence of excess benzonitrile generated osmabenzene [Os{CHC(PPh3)C(CH3)CHCH}(PhCN)(2)(PPh3)(2)]Cl-2 (14). Complexes 11, 12 and 14 are in fact isomers. In the absence of excess benzonitrile, the isolated dicationic 12 and 14 readily dissociate the benzonitrile ligands in solution to produce the neutral complex [Os{CH=C(PPh3)C(CH3)=(eta(2)-C=CH2)}Cl-2(PPh3)(2)] (13) and the monocationic osmabenzene [Os{CHC(PPh3)C(CH3) CHCH}Cl(PhCN)(PPh3)(2)]BPh4 (15) respectively. Mechanisms for the formation of osmabenzene 14 from 11 and 12 are proposed based on DFT calculations.New Century Excellent Talents in University of China [NCET-040603]; National Science Foundation of China [20572089, 20872123

Synthesis of Ruthena-polycyclic Complexes by Ruthenium-Vinylcarbene Complex

National Basic Research Program of China [2012CB821600]; National Natural Science Foundation of China [20925208, 21174115, 21272193]; Program for Changjiang Scholars and Innovative Research Team in UniversityTreatment of ruthenium-vinylcarbene complex [Ru(CHC(PPh3)CH(2-Py))Cl2PPh3]BF4 (1) and PPh3 with nucleophilic reagents 1120, CH3OH, NH2Ph, or 2-mercaptopyridine led to the ruthena-polycyclic complexes [Ru(CHC(PPh3)CHR(2-Py))Cl(PPh3)BF4 [R = OH (2), R = OCH3 (3), R = NHPh (4)] or [Ru(CHC(PPh3)CH(S(2-P3))(2-Py))PPh3(S(2-Py)](3)BF4 (5). They are stable under air at solid state. CH3OH in the reaction is not only the reagent but also the solvent and the reaction must be heated at 60 *0 for 6 h. All the other reactions were carried out at room temperature in CH2C12. The crystals of 4 and 5 were grown from CH2C12 and CHC13 solutions layered with diethyl ether, respectively. The structures 4 and 5 were determined by X-ray crystallography. The crystal size of 4 is alpha=1.29145(3) nm, beta=1.37687(5) nm, c=1.86914(4) nm, a=92.114(2), beta= 106.271(2), gamma=96.333(3) and the size of 5 is a= 1.15333(18) nm, b= 1.20072(19) rim, c=1.9081(3) nm, a=88.466(3), /3=87.918(3), y=79.521(3). In addition, refluxing 1 with PPh3 in CHCl3 for 6 h to produce red solid [Ru(CHC(PPh3)CH(2-Py))Cl-2(PPh3)(2)]BF4 (6). The reaction of complex 6 with MEI at room temperature for 3 h afforded the (mu-Cl)(3)-bridged bisruthenium-vinylcarbene complex [{Ru(CHC(PPh3)CH(2-Py))PPh3}(2)(mu-Cl)(3)](BF4)(3) (7) in 87% yield. The crystal of 6 was grown from CH3COCH3 solution layered with diethyl ether, and the crystal of 7 was grown from CHCl3 solution layered with diethyl ether. The structures of 6 and 7 were also determined by X-ray crystallography. The crystal size of 6 and 7 are alpha=1.13777(3) nm, beta= 1.56466(7) nm, c= 1.79541(7) nm, alpha=75.822(3), beta=79.502(2), y= 79.259(3), a=1.68830(3) nm, beta=2.33421(4) nm, c=2.48603(4) nm, alpha=90, beta=96.5530(10), gamma=90 degrees, respectively. The CCDC number for 3, 5, 6, and 7 are 945539 (3), 945538 (5), 945541 (6), and 945542 (7). All these complexes were fully characterized by elemental analysis and NMR spectroscopy

SCFRMF mediates degradation of the meiosis-specific recombinase DMC1

Abstract Meiotic recombination requires the specific RecA homolog DMC1 recombinase to stabilize strand exchange intermediates in most eukaryotes. Normal DMC1 levels are crucial for its function, yet the regulatory mechanisms of DMC1 stability are unknown in any organism. Here, we show that the degradation of Arabidopsis DMC1 by the 26S proteasome depends on F-box proteins RMF1/2-mediated ubiquitination. Furthermore, RMF1/2 interact with the Skp1 ortholog ASK1 to form the ubiquitin ligase complex SCFRMF1/2. Genetic analyses demonstrate that RMF1/2, ASK1 and DMC1 act in the same pathway downstream of SPO11-1 dependent meiotic DNA double strand break formation and that the proper removal of DMC1 is crucial for meiotic crossover formation. Moreover, six DMC1 lysine residues were identified as important for its ubiquitination but not its interaction with RMF1/2. Our results reveal mechanistic insights into how the stability of a key meiotic recombinase that is broadly conserved in eukaryotes is regulated

Nine-Membered Osmacycles Derived from Metathesis Reactions between Alkynes and an Osmafuran

Ring-expansion reactions of the five-membered osmafuran Os{=CHC(PPh3)=C(O) OEt}Cl-2(PPh3)(2) (1) via alkyne insertion have been investigated, which lead to the formation of several nine-membered osmacycles. Reaction of 1 with PhC CH gives the nine-membered complexes Os{=CPhCH=CPh=eta(2)- CH=CHC(PPh3)=C(O)OEt}Cl-2(PPh3) as a mixture of a couple of isomers 2a and 2b with different disposition of the two chloride ligands on the metal centers. The reaction involves a head-to-tail double insertion of PhC CH into osmacycle 1 via [2 + 2] cycloaddition process, which is relevant to the polymerization of alkynes by metathesis reaction. Treatment of the mixture of 2a and 2b with PMe3 gives selectively Os{=CPhCH=CPh-eta(2)-CH=CHC(PPh3)=C(O)OEt}Cl-2(PMe3) (3), the PMe3-substituted counterpart of 2a. These complexes might serve as the intermediates for alkyne polymerization which are stabilized by the coordination of internal olefin. Heating the mixture of 2a and 2b in CHCl3 under reflux gives complex Os{eta(2)-CHPh=CHCPh=CHCC(PPh3)C(O)OEt)Cl-2(PPh3) (4) by an intramolecular hydrogen shift. In addition, reaction of 1 with HC CCH(OH)Ph affords [Os{O=CPhCH2-eta(2)- CH=CHC(PPh3)=C(O)OEt}Cl(PPh3)(2)]Cl (5) as a monoinsertion product, which can dissociate a phosphine ligand under reflux in CH2Cl2 to give complex Os{O=CPhCH2-eta(2)-CH=CHC(PPh3)=C(O)OEt}Cl-2(PPh3) (6). The one of the alpha-H of the carbonyl group in complex 5 can be deprotonated by NEt3 to give an eta(3)-allylic structure Os[eta(3)-CH{CPh(=O)}CHCHC(PPh3)=C(O)OEt]Cl(PPh3)(2) (7). Treatment of 7 in CHCl3 with 1 equiv of HCl regenerates 5. All of the complexes can be prepared under mild condition in good yield. Moreover, these reactions provide convenient and efficient routes to synthesize the nine-membered osmacycles. Complexes 1, 3, 4, 5', 6, and 7 have been characterized by X-ray diffraction analysis.National Science Foundation of China [20572089, J0630429, 20872123

Mechanistic Study of Indolizine Heterocycle Formation by Ruthenium(II)-Assisted Three-Component Cross-Coupling<b>/</b>Cyclization

In the presence of the acid HBF₄, 3-alkenyl-2-phosphonium indolizines <b>3a</b>–<b>c</b> can be produced respectively by adding PhCCCOCH₃ (<b>2a</b>), CH₃OCOCCCOOCH₃ (<b>2b</b>), and CH₃CH₂CCCOCH₃ (<b>2c</b>) to a mixture of ruthenium complex RuCl₂(PPh₃)₃ and the propargyl alcohol (2-Py)­CH­(OH)­CCH (<b>1</b>). We carefully investigated the mechanism of this reaction by means of structurally characterizing two key intermediates, ruthenium vinyl (<b>4</b>) and ruthenium carbene (<b>5</b>), and by deuterium-labeling experiments. A plausible mechanism is proposed, which involves addition of a proton to an alkyne carbon and the insertion of an alkyne into the Cα bond of an alkenylcarbene group, followed by an α<i>-</i>H elimination and reductive elimination

CD73-positive pediatric urethral mesenchymal stem-like cell-derived small extracellular vesicles stimulate angiogenesis

Introduction: Angiogenesis plays an important role in the repair of urethral injury, and stem cells and their secretomes can promote angiogenesis. We obtained pediatric urethral mesenchymal stem-like cells (PU-MSLCs) in an earlier study. This project studied the pro-angiogenic effect of PU-MSLC-derived small extracellular vesicles (PUMSLC-sEVs) and the underlying mechanisms. Materials and methods: PUMSLCs and PUMSLC-sEVs were cultivated and identified. Then, biological methods such as the ethynyl deoxyuridine (EdU) incorporation assay, Cell Counting Kit-8 (CCK-8) assay, scratch wound assay, Transwell assay, and tube formation assay were used to study the effect of PUMSLC-sEVs on the proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs). We explored whether the proangiogenic effect of PUMSLC-sEVs is related to CD73 and whether adenosine (ADO, a CD73 metabolite) promoted angiogenesis. GraphPad Prism 8 software was used for data analysis. Results: We observed that PUMSLC-sEVs significantly promoted the proliferation, migration, and tube-forming abilities of HUVECs. PUMSLC-sEVs delivered CD73 molecules to HUVECs to promote angiogenesis. The angiogenic ability of HUVECs was enhanced after treatment with extracellular ADO produced by CD73, and PUMSLC-sEVs further promoted angiogenesis by activating Adenosine Receptor A2A (A2AR). Conclusions: These observations suggest that PUMSLC-sEVs promote angiogenesis, possibly through activation of the CD73/ADO/A2AR signaling axis