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To establish the movement relationship for the roof breaking under shallow mining conditions, the mechanical model of the roof rock beam was built, then the structure instability process of the roof rock beam was analyzed. The changing criterion of the vertical displacement was established and the relationship between the deflection and the rotary motion of roof block was determined. Regarding a mining face in Shangwan Mine, the responsing laws of the deflection and horizontal thrust of the roof rock beam were obtained through FLAC3D numerical analysis. The results show that the structure instability of the cracked roof rock beam depends on the interaction between the vertical load and the horizontal thrust. For the roof rock beam, when the vertical load keeps constant, the horizontal thrust fluctuating rises with increasing deflection. The horizontal thrust increases constantly with the deeper buried depth and the smaller span. Keywords: Shallow mining, Working face, Roof rock beam, Structure stability, Horizontal thrust

The study aimed to develop an effective method to quantitate HBV covalently closed circular DNA (cccDNA) using small section of formalin fixed paraffin-embedded (FFPE) liver biopsy.Plasmid-safe ATP-dependent DNase (PSAD)-treated samples were subjected to rolling circle amplification (RCA) prior to real-time PCR mediated by cccDNA-selective primers. Human beta-actin gene was used as a reference control.Compared to the classical method, i.e., PSAD digestion+real-time PCR, introduction of RCA increased the lower limit of detection for about 2 logs with good inter- and intra-assay reproducibility. HBV cccDNA was detected in 91.5% (119/130) of the FFPE samples. The cccDNA levels (copy/cell) between FFPE liver tissues and fresh frozen counterpart tissues were comparable. The median of cccDNA level in HBeAg-positive patients was higher than that in HBeAg-negative ones (52.60 vs. 31.25copies/cell, P0.01). Intrahepatic cccDNA level was positively correlated with intrahepatic HBV total DNA level, but not obviously correlated with serum HBV DNA or alanine aminotransferase levels.The method could sensitively and specifically quantitate intrahepatic HBV cccDNA in micro FFPE liver biopsy tissue for evaluation of HBV replication status in the liver.

Background/Aims Functionally impaired dendritic cells (DCs) play important roles in suppressing host immune responses and facilitating viral persistence in chronic hepatitis B virus (HBV) infection. However, little is known regarding the status of intrahepatic DCs in HBV infection. Methods Based on availability, 11 recipient liver samples were obtained from acute-on-chronic hepatitis B liver failure (ACHBLF) patients who had undergone liver transplantation. The frequencies, phenotypes, and functions of intrahepatic DC subsets were analyzed. Results Both plasmacytoid dendritic cells (pDCs) and myeloid dendritic cells (mDCs) extensively infiltrated the liver of the ACHBLF patients and expressed mature phenotypes therein. In particular, activated hepatic pDCs produced interferon (IFN)-α, which subsequently induced interleukin (IL)-12 and IL-10 production via toll-like receptor-9 ligation in liver-infiltrating lymphocytes cultured in vitro . However, blockade of IFN-α production significantly reduced the cytokine production of the LILs. Further, a significantly low frequency of peripheral pDCs and highly reduced IFN-α production were observed in a large cohort of the ACHBLF patients, particularly in the non-survivors. Moreover, a persistently upregulated expression of hepatic IFN-α-associated genes was observed in the ACHBLF patients during disease progression. Conclusions Activated pDCs accumulated in large numbers in the liver of the ACHBLF patients and regulated local immune responses in chronic HBV infection.