Non-invasive Self-attention for Side Information Fusion in Sequential Recommendation

Sequential recommender systems aim to model users' evolving interests from their historical behaviors, and hence make customized time-relevant recommendations. Compared with traditional models, deep learning approaches such as CNN and RNN have achieved remarkable advancements in recommendation tasks. Recently, the BERT framework also emerges as a promising method, benefited from its self-attention mechanism in processing sequential data. However, one limitation of the original BERT framework is that it only considers one input source of the natural language tokens. It is still an open question to leverage various types of information under the BERT framework. Nonetheless, it is intuitively appealing to utilize other side information, such as item category or tag, for more comprehensive depictions and better recommendations. In our pilot experiments, we found naive approaches, which directly fuse types of side information into the item embeddings, usually bring very little or even negative effects. Therefore, in this paper, we propose the NOninVasive self-attention mechanism (NOVA) to leverage side information effectively under the BERT framework. NOVA makes use of side information to generate better attention distribution, rather than directly altering the item embedding, which may cause information overwhelming. We validate the NOVA-BERT model on both public and commercial datasets, and our method can stably outperform the state-of-the-art models with negligible computational overheads.Comment: Accepted at AAAI 202

Synthesis and Evaluation of a New Type of Small Molecule Epigenetic Modulator Containing Imidazo[1,2-b][1,2,4]triazole Motif

Epigenetic modifications such as DNA methylation is important for many cellular processes, such as cell differentiation and cell death. The disorder of epigenetic state is closely related to human diseases, especially cancers. DNA methylation is a well-characterized epigenetic modification which is related to gene silencing and is considered as a repressive epigenetic mark. DNA methylation caused gene repression can be derepressed by chemical agents. Small molecules targeting DNA methyltransferases, histone deacetylases, and other regulatory factors can activate genes silenced by DNA methylation. However, more and more studies have shown that histone deacetylation is not the only downstream event of DNA methylation. Some additional, unknown mechanisms that promote DNA methylation-mediated gene silencing may exist. Recently, through high-throughput screening using a 308,251-member chemical library to identify potent small molecules that derepress an EGFP reporter gene silenced by DNA methylation, we identified seven hit compounds that did not directly target bulk DNA methylation or histone acetylation. Three of them (LX-3, LX-4, LX-5) were proven to selectively activate the p38 MAPK pathway in multiple cell types. In order to identify the exact cellular targets of these compounds, we turn to work on the SAR study of LX-3 by constructing a structurally diverse chemical library based on the imidazo[1,2-b][1,2,4]triazole core structure via diversity-oriented synthesis. Our work provides a general approach to efficiently access diverse heterocyclic molecules with interesting epigenetic modulation activities

Incidence and Etiology of Drug-Induced Liver Injury in Mainland China

Background & Aims: We performed a nationwide, retrospective study to determine the incidence and causes of drug-induced liver injury (DILI) in mainland China.Methods: We collected data on a total of 25,927 confirmed DILI cases, hospitalized from 2012 through 2014 at 308 medical centers in mainland China. We collected demographic, medical history, treatment, laboratory, disease severity, and mortality data from all patients. Investigators at each site were asked to complete causality assessments for each case whose diagnosis at discharge was DILI (n=29,478) according to the Roussel Uclaf Causality Assessment Method.Results: Most cases of DILI presented with hepatocellular injury (51.39%; 95% CI, 50.76–52.03), followed by mixed injury (28.30%; 95% CI, 27.73–28.87) and cholestatic injury (20.31%; 95% CI, 19.80–20.82). The leading single classes of implicated drugs were traditional Chinese medicines or herbal and dietary supplements (26.81%) and anti-tuberculosis medications (21.99%). Chronic DILI occurred in 13.00% of the cases and, although 44.40% of the hepatocellular DILI cases fulfilled Hy’s Law criteria, only 280 cases (1.08%) progressed to hepatic failure, 2 cases underwent liver transplantation (0.01%), and 102 patients died (0.39%). Among deaths, DILI was judged to have a primary role in 72 (70.59%), a contributory role in 21 (20.59%), and no role in 9 (8.82%). Assuming the proportion of DILI in the entire hospitalized population of China was represented by that observed in the 66 centers where DILI capture was complete, we estimated the annual incidence in the general population to be 23.80 per 100,000 persons (95% CI, 20.86–26.74). Only hospitalized patients were included in this analysis, so the true incidence is likely to be higher.Conclusions: In a retrospective study to determine the incidence and causes of drug-induced liver injury (DILI) in mainland China, the annual incidence in the general population was estimated to be 23.80 per 100,000 persons—higher than that reported from western countries. Traditional Chinese medicines, herbal and dietary supplements, and anti-tuberculosis drugs were the leading causes of DILI in mainland Chin

CO2 activation and fixation: highly efficient syntheses of hydroxy carbamates over Au/Fe2O3

This paper reports an effective route for the syntheses of hydroxy carbamates from the reaction of CO2, epoxides and amines catalyzed by a Au/Fe2O3 catalyst. Under the optimized reaction conditions, various hydroxy carbamates were successfully synthesized with 92-98% isolated yields. The catalyst could be reused for several runs without deactivation. A plausible reaction mechanism was proposed by which the hydroxy carbamate was formed through an ammonium carbamate intermediate and the catalyst mainly promoted further nucleophilic addition between the epoxide and ammonium carbamate

Mechanical Load-Induced Atomic-Scale Deformation Evolution and Mechanism of SiC Polytypes Using Molecular Dynamics Simulation

Silicon carbide (SiC) is a promising semiconductor material for making high-performance power electronics with higher withstand voltage and lower loss. The development of cost-effective machining technology for fabricating SiC wafers requires a complete understanding of the deformation and removal mechanism. In this study, molecular dynamics (MD) simulations were carried out to investigate the origins of the differences in elastic–plastic deformation characteristics of the SiC polytypes, including 3C-SiC, 4H-SiC and 6H-SiC, during nanoindentation. The atomic structures, pair correlation function and dislocation distribution during nanoindentation were extracted and analyzed. The main factors that cause elastic–plastic deformation have been revealed. The simulation results show that the deformation mechanisms of SiC polytypes are all dominated by amorphous phase transformation and dislocation behaviors. Most of the amorphous atoms recovered after completed unload. Dislocation analysis shows that the dislocations of 3C-SiC are mainly perfect dislocations during loading, while the perfect dislocations in 4H-SiC and 6H-SiC are relatively few. In addition, 4H-SiC also formed two types of stacking faults

Investigating the Width of Isolated Coal Pillars in Deep Hard-Strata Mines for Prevention of Mine Seismicity and Rockburst

In deep mines, a reasonable design of the widths of isolated coal pillars (ICPs) is critically important, particularly for hard-strata mines. This is because the frequent occurrence of mine seismicity (MS) and rockburst in deep mines often arises from the inappropriate widths of the remnant ICPs. To address this problem, this paper takes the ICP of Yingpanhao Coal Mine in Inner Mongolia in China as the engineering case study and then presents a mechanical model to illuminate the occurrence mechanism of MS induced by the mining on both sides of ICPs. The results indicate that, after the mining on both sides of ICPs, the ICPs will produce a vertical compressive deformation, and the overlying high main key stratum (MKS) will experience a flexure deformation. When the limited deflection of MKS is less than the compression of ICPs, the MKS will be fractured, and the released energy may lead to MS. Based on the mechanism model, a design criterion is proposed for ICP widths; this criterion can effectively reduce the risk of the induced rockburst and MS. Then the occurrence mechanism of MS and the design basis for ICP width are verified by numerical simulation and field microseismic monitoring. The results in this paper may be used as a theoretical guidance for rational ICP design in deep mines and may help mitigate the risk of rockburst and MS from early mining stages

Atomic understanding of the evolutionary mechanism of fused glass densification generation during single particle scratching

The densification of fused glass during processing has a significant impact on the performance and application of fused glass components. However, the precise atomic mechanisms underlying densification remain elusive. In this study, we explore the atomic mechanisms responsible for densification in fused glass during single particle scratching, with a focus on the scratching depths and environmental humidity. We employ reactive force field molecular dynamics (ReaxFF MD) simulations for our investigation. We subjected models to scratching under various humidity conditions using a spherical virtual indenter with a 20 Å radius. The scratching depths were set at 10 Å and 15 Å, respectively, with a constant scraping speed of 40 m/s. Our findings indicate that water molecules impede lateral atom movement on the fused glass surface while enhancing vertical flow. Furthermore, water molecules facilitate the volume recovery of fused glass following scratching. The transfer of hydrogen (H) atoms within the fused glass, facilitated by Si–O–H⋯O–Si structures, plays a crucial role in promoting volume recovery. The ultimate density distribution of fused glass results from a combination of atomic displacement during scratching and subsequent volume recovery. This study enhances our atomic-level understanding of densification generation in fused glass