Pathways of liquefied petroleum gas pyrolysis in hydrogen plasma:A density functional theory study

A density functional theory （DFT） study has been conducted in this work to investigate the pyrolysis pathways of propane and n-butane, which are the main components of liquefied petroleum gas （LPG）, for better understanding the pyrolysis behavior of LPG in hydrogen thermal plasma. Over 60 possible reactions are considered. The reaction enthalpies and activation energies of these reactions are calculated and analyzed with a Gaussian method of B3LYP and basic set of 6-31G （d,p）. A most possible reaction pathway is brought up. According to this reaction pathway, the main products of LPG pyrolysis are acetylene, ethylene, methane, ethane and extra hydrogen. Acetylene mainly comes from the pyrolysis of propylene and ethylene, and hydrogen abstraction reactions are the main source of extra hydrogen gas. Active H. radicals are found to play a very important role in many reactions, and they can remarkably lower the energies needed for reactions.

ASF1A-dependent P300-mediated histone H3 lysine 18 lactylation promotes atherosclerosis by regulating EndMT

Endothelial-to-mesenchymal transition(EndMT)is a key driver of atherosclerosis.Aerobic glycolysis is increased in the endothelium of atheroprone areas,accompanied by elevated lactate levels.Histone lactylation,mediated by lactate,can regulate gene expression and participate in disease regulation.However,whether histone lactylation is involved in atherosclerosis remains unknown.Here,we report that lipid peroxidation could lead to EndMT-induced atherosclerosis by increasing lactatedependent histone H3 lysine 18 lactylation(H3K18la)in vitro and in vivo,as well as in atherosclerotic patients’arteries.Mechanistically,the histone chaperone ASF1A was first identified as a cofactor of P300,which precisely regulated the enrichment of H3K18la at the promoter of SNAI1,thereby activating SNAI1 transcription and promoting EndMT.We found that deletion of ASF1A inhibited EndMT and improved endothelial dysfunction.Functional analysis based on Apoe^(KO)Asf1a^(ECKO) mice in the atherosclerosis model confirmed the involvement of H3K18la in atherosclerosis and found that endotheliumspecific ASF1A deficiency inhibited EndMT and alleviated atherosclerosis development.Inhibition of glycolysis by pharmacologic inhibition and advanced PROTAC attenuated H3K18la,SNAI1 transcription,and EndMT-induced atherosclerosis.This study illustrates precise crosstalk between metabolism and epigenetics via H3K18la by the P300/ASF1A molecular complex during EndMT-induced atherogenesis,which provides emerging therapies for atherosclerosis.

Influences of preload on the friction and wear properties of high-speed instrument angular contact ball bearings

For starved-oil or solid lubrication of high-speed instrument angular contact ball bearings, friction heating and wear are the main reasons of bearing failures. This paper presents a dynamic wear simulation model to investigate the impacts of different preload methods and the changes of preload caused by wear on bearing wear life. The integral value QV of stress and sliding velocity in the contact ellipses between a ball and the inner and outer races determines friction heating and wear. The changes of QV with the friction coefficient and the wear volume under constantforce preload and fixed-position preload are analyzed. Results show that under the same initial preload, the QV decreases with an increase of the friction coefficient for both preload methods, and the latter is slightly larger. The wear of the ball and the race is equivalent to the ball diameter reduction.The QV of constant-force preload is almost not changed with a decrease of the ball diameter, but for fixed-position preload, the value decreases firstly and then increases substantially due to insufficient preload, and slipping occurs, the ball diameter is reduced by 0.025%, while the preload is reduced by 60.33%. An estimation of the bearing wear life under different preload methods requires a consideration of the changes in the wear rate of bearing parts.

Non-canonical STING-PERK pathway dependent epigenetic regulation of vascular endothelial dysfunction via integrating IRF3 and NF-κB in inflammatory response

Inflammation-driven endothelial dysfunction is the major initiating factor in atherosclerosis,while the underlying mechanism remains elusive.Here,we report that the non-canonical stimulator of interferon genes(STING)-PKR-like ER kinase(PERK)pathway was significantly activated in both human and mice atherosclerotic arteries.Typically,STING activation leads to the activation of interferon regulatory factor 3(IRF3)and nuclear factor-kappa B(NF-κB)/p65,thereby facilitating IFN signals and infammation.In contrast,our study reveals the activated non-canonical STING-PERK pathway increases scaffold protein bromodomain protein 4(BRD4)expression,which encourages the formation of super-enhancers on the proximal promoter regions of the proinflammatory cytokines,thereby enabling the transactivation of these cytokines by integrating activated IRF3 and NF-κB via a condensation process.Endothelium-specific STING and BRD4 deficiency significantly decreased the plaque area and inflammation.Mechanistically,this pathway is triggered by leaked mitochondrial DNA(mtDNA)via mitochondrial permeability transition pore(mPTP),formed by voltage-dependent anion channel 1(VDAC1)oligomer interaction with oxidized mtDNA upon cholesterol oxidation stimulation.Especially,compared to macrophages,endothelial STING activation plays a more pronounced role in atherosclerosis.We propose a non-canonical STING-PERK pathway-dependent epigenetic paradigm in atherosclerosis that integrates IRF3,NF-κB and BRD4 in inflammatory responses,which provides emerging therapeutic modalities for vascular endothelial dysfunction.

Starved lubrication analysis of angular contact ball bearing based on a multi-degree-of-freedom tribo-dynamic model

When the oil supply is not adequate to maintain the ideal lubrication,angular contact ball bearing will enter into the starved lubrication regime resulting in the potential performance degradation and consequently the severe failures.To study the effects of starved lubrication on the performance of angular contact ball bearing,this paper first proposes a multi-degree-of-freedom(DOF)tribo-dynamic model by introducing five-DOF inner ring,six-DOF balls,and six-DOF cage.The model considers the starved lubrication in the ball-raceway contact and the full multi-body interactions between the bearing components.With different ball-raceway starvation degrees being analyzed,the effects of starved lubrication on the bearing tribo-dynamic performance are first revealed.By comparison,it is found that the oil film thickness,the skidding performance,and the traction forces in the ball-raceway contact are significantly influenced by the starvation degrees.It is also found that the starvation-induced change of the ball-pocket contact force is dramatical under combined loads,and the maximum contact force under this load condition increases with the increasing starvation degrees.

Memristive switching in the surface of a charge-density-wave topological semimetal

Owing to the outstanding properties provided by nontrivial band topology,topological phases of matter are considered as a promising platform towards low-dissipation electronics,efficient spin-charge conversion,and topological quantum computation.Achieving ferroelectricity in topological materials enables the non-volatile control of the quantum states,which could greatly facilitate topological electronic research.However,ferroelectricity is generally incompatible with systems featuring metallicity due to the screening effect of free carriers.In this study,we report the observation of memristive switching based on the ferroelectric surface state of a topological semimetal(TaSe_(4))2I.We find that the surface state of(TaSe_(4))2I presents out-of-plane ferroelectric polarization due to surface reconstruction.With the combination of ferroelectric surface and charge-density-wave-gapped bulk states,an electric-switchable barrier height can be achieved in(TaSe_(4))2I-metal contact.By employing a multi-terminal-grounding design,we manage to construct a prototype ferroelectric memristor based on(TaSe_(4))2I with on/off ratio up to 103,endurance over 103 cycles,and good retention characteristics.The origin of the ferroelectric surface state is further investigated by first-principles calculations,which reveal an interplay between ferroelectricity and band topology.The emergence of ferroelectricity in(TaSe_(4))2I not only demonstrates it as a rare but essential case of ferroelectric topological materials,but also opens new routes towards the implementation of topological materials in functional electronic devices.

Absence of metallicity and bias-dependent resistivity in low-carrier-density EuCd_(2)As_(2)

EuCd_(2)As_(2)was theoretically predicted to be a minimal model of Weyl semimetals with a single pair of Weyl points in the ferromagnet state.However,the heavily p-doped Eu Cd_(2)As_(2)crystals in previous experiments prevent direct identification of the semimetal hypothesis.Here,we present a comprehensive magneto-transport study of high-quality Eu Cd_(2)As_(2)crystals with ultralow bulk carrier density(10^(13)cm^(-3)).In contrast to the general expectation of a Weyl semimetal phase,Eu Cd_(2)As_(2)shows insulating behavior in both antiferromagnetic and ferromagnetic states as well as surface-dominated conduction from band bending.Moreover,the application of a dc bias current can dramatically modulate the resistance by over one order of magnitude,and induce a periodic resistance oscillation due to the geometric resonance.Such nonlinear transport results from the high nonequilibrium state induced by an electrical field near the band edge.Our results suggest an insulating phase in Eu Cd_(2)As_(2)and put a strong constraint on the underlying mechanism of anomalous transport properties in this system.

Autophagy enhanced by curcumin ameliorates inflammation in atherogenesis via the TFEB-P300-BRD4 axis

Disturbance of macrophage-associated lipid metabolism plays a key role in atherosclerosis.Crosstalk between autophagy deficiency and inflammation response in foam cells(FCs) through epigenetic regulation is still poorly understood. Here, we demonstrate that in macrophages, oxidized lowdensity lipoprotein(ox-LDL) leads to abnormal crosstalk between autophagy and inflammation,thereby causing aberrant lipid metabolism mediated through a dysfunctional transcription factor EB (TFEB)-P300-bromodomain-containing protein 4(BRD4) axis. ox-LDL led to macrophage autophagy deficiency along with TFEB cytoplasmic accumulation and increased reactive oxygen species generation. This activated P300 promoted BRD4 binding on the promoter regions of inflammatory genes, consequently contributing to inflammation with atherogenesis. Particularly, ox-LDL activated BRD4-dependent super-enhancer associated with liquid-liquid phase separation(LLPS) on the regulatory regions of inflammatory genes. Curcumin(Cur) prominently restored FCs autophagy by promoting TFEB nuclear translocation, optimizing lipid catabolism, and reducing inflammation. The consequences of P300 and BRD4 on super-enhancer formation and inflammatory response in FCs could be prevented by Cur. Furthermore, the anti-atherogenesis effect of Cur was inhibited by macrophage-specific Brd4 overexpression or Tfeb knock-out in Apoe knock-out mice via bone marrow transplantation. The findings identify a novel TFEB-P300-BRD4 axis and establish a new epigenetic paradigm by which Cur regulates autophagy, inhibits inflammation, and decreases lipid content.

Real-Time Analysis and Prediction System for Rail Transit Passenger Flow Based on Deep Learning

With the rapid development of urban rail transit,rail transit plays an important role in alleviating city congestion.In recent years,with increasing pas-sengerflow,there has been huge pressure on passengerflow management.To address this problem,we propose a novel system to provide real-time statistics and predictions of passengerflow based on big data technology and deep learning technology.Moreover,the passengerflow is visualized efficiently in this system.It can provide refined passengerflow information so that people can make more rational decisions in terms of operation and planning,deploy contingency plans to avoid emergency situations,and integrate passengerflow analysis with train production,scheduling and operation to achieve cost reduction and efficiency enhancement.