Congcong Chen

Caverns are generally formed by a combination of regional geological action and groundwater, and their improper treatment will inevitably lead to dangerous conditions in underground works. To detect the specific failure mechanism of tunnel-surrounding rock induced by invisible caverns, a true triaxial compression test is conducted, accompanied by acoustic emission technology and an internal borehole camera, for monitoring the acoustic response and visible secondary cracks, and a corresponding DEM simulation is carried out to reveal the meso-mechanism. The results indicate the following: (1) The invisible cavern demonstrates a negative influence on the stability of the tunnel and leads to a 25.82% reduction in the peak z-axis load of the specimens. (2) The acoustic emission results show that the relatively severe dominant failures mainly occur near the peak stress in all types of specimens, and the speed and intensity of the cavern-existing specimen is significantly greater than that of the cavern-free specimen. (3) The cavity-free tunnel shows mirror-symmetric splitting failure on the left and right sidewalls, while the secondary cracks appear earlier and show asymmetrical distribution in the cavern-existing specimen, and the volume of broken rock blocks near the free surface is larger. (4) The cavern directly changes the failure process of the tunnel-surrounding rock (intermediate rock failure occurs earlier than splitting failure), the distribution of principal stress, and the corresponding mechanism of secondary failures. (5) Application of the displacement and velocity trend fields helped to reveal accurate failure procedures in the true triaxial test.

To characterise the relationships among the hazards associated with tailings storage facility (TSF) dam failure, interpretive structural modelling (ISM) is used to hierarchise, structuralise and visualise them. Based on evidence, 15 hazards in four categories are identified, and are classified into seven levels and four clusters. The results show that seven hazards can be regarded as the fundamental hazards. The majority of hazards associated with technology factor can be seen as transactional hazards and are closely related to the water balance problem. The proposed ISM method offers theoretical reference and improves risk management for the TSF and the mining industry.

As one of the most concerned risk sources of mining enterprises, the safety and stability of the tailings storage facility (TSF) is closely connected to the operating activity, surrounding ecological environment, and residents' lives safety and properties safety. In order to evaluate the risk of the tailings dam break, the extension matter-element model has been applied in the work. First, the risk evaluation indicator system was established, included 3 levels, 4 criteria and 17 individual indicators. Next, the weight of each indicator was computed by using the analytic hierarchy process (AHP) method. Then, the classical field, controlled field and closeness function within the extension matter-element model were determined considering the TSF height and volume, and the principle of the maximum membership degree has been improved by the closeness. Finally, a case study was illustrated to demonstrate the effectiveness of the model. The result indicated that the target TSF operated at a relatively lower risk level, which accurately reflected the real operating situation. This work can provide a reasonable reference for dam break risk evaluation.

Background & Aims: Previous genome‐wide association studies (GWAS) have identified multiple susceptible variants associated with persistent hepatitis B virus (HBV) infection. However, most of these variants are located in the noncoding regions, which make it difficult to determine the effective genes underlying these associations. We performed a two‐stage study, in the first stage we integrated RNA sequencing data of liver tissues and high‐density genotyping data from the Genotype‐Tissue Expression (GTEx) project with our previous GWAS data to conduct a transcriptome‐wide association study (TWAS) on HBV infection. Firstly, the cis‐heritable genes were screened by a genetic relatedness matrix of genome‐wide complex trait analysis (GCTA) from GTEx data. Then, the genetic expression of 2587 cis‐heritable genes was predicted by restricted maximum likelihood (REML) of genome‐wide efficient mixed‐model association (GEMMA) in our GWAS data with 951 HBV carrier cases and 937 HBV cleared controls. Next, we investigated the associations between predictive expression levels and persistent HBV infection risk. Gene set enrichment analysis (GSEA) was applied to infer the function of the identified genes. To identify the causal single nucleotide polymorphisms (SNPs) of HBV infection risk, we conducted the expression quantitative trait loci (eQTL)‐based stepwise logistic regression analysis in the regions around 1 Mb of these genes and validated the association between 994 health controls and 994 HBV‐persistent infection cases by genotyping experiment. In the second stage, 1538 HBV‐related hepatocellular carcinoma (HCC) cases and 1465 persistent HBV infection controls were collected to determine the effect of these variants on HBV‐related HCC as well, which were examined by the additive model in logistic regression analysis. We identified seven genes associated with HBV infection. In the classic human leukocyte antigen (HLA) region, three novel genes BAK1, HLA‐DOB and C4A (Z range from −3.95 to −3.64, P range from 7.84 × 10⁻⁵ to 2.00 × 10⁻⁴), as well as two genes (HLA‐DPA1 and HLA‐DPB1) were reported by previous GWAS. In the non‐HLA region, immune related at newly identified loci, PARP9 (Z = 3.69, P = 2.20 × 10⁻⁴) at 3q21.1. At 22q11.21, we identified TMEM191A (Z = 3.55, P = 3.80 × 10⁻⁴) as a target gene in addition to the reported non‐cis‐heritable gene UBE2L3. After further stepwise logistic regression analysis and validation, we identified eight variants independently associated with persistent HBV infection. Among those variants, the additive model showed that two SNPs associated with HBV‐related HCC risk (rs9272714 and rs9394194, OR range from 1.20 to 1.25, P range from 1.19 × 10⁻⁴ to 3.97 × 10⁻⁴). By integrating transcriptome data, our study not only identified new susceptibility loci of persistent HBV infection but also determined the potential target genes at reported loci, which provided insight into the genetic aetiology of persistent HBV infection and related HCC.

Rare earth elements (REE) are widely used in high technologies, medical devices, and military defense systems, and are especially indispensable in emerging clean energy. Along with the growing market of green energy in the next decades, global demand for REE will increase continuously, which will put great pressure on the current REE supply chain. The global REE production is currently mainly concentrated in China and Australia; they respectively contributed 85% and 10% in 2016. However, there are 178 deposits widely distributed in the world, and reported REE resources as of 2017 totaled 478 megaton (Mt) rare earth oxides (REO); 58% of these deposits contained exceed 0.1 Mt REO; 59 deposits have been technically assessed. These resources could sustain the global REE production at the current pace for more than a hundred years. It is noted that REE demand from clean technologies will reach 51.9 thousand metric tons (kt) REO in 2030, Nd and Dy, respectively, comprising 75% and 9%, while these two elements comprise 15% and 0.52% of the global REE resources, respectively. This indicates that Nd and Dy will strongly influence the development of exploring new REE projects and clean technologies in the next decades.