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In the operation of bolter miners, the cutting arm is an essential and weak part and its fatigue life directly affects its performance. This study aimed to investigate the influence of the cutting head load on the fatigue life of a cutting arm using the DEM-MFBD (Discrete Element Method-Multi Flexible Body Dynamics) bi-directional coupling technique. The EJM340 bolter miner was chosen as the research object, and a three-dimensional solid model of the bolter miner was built using the RecurDyn software. The cutting arm was flexibly modelled, and the tunnel model was built using the EDEM software. The motion parameters of the bolter miner and cutting head load were transferred through the bi-directional coupling interface to obtain the loads and stress parameters during the entire tunnel cutting process. Based on the stress-time variation, the fatigue life of the cutting arm was calculated, the overall damage and crack initiation locations were obtained, and the minimum number of cutting arm cycles was determined. The accuracy of the virtual model is verified through field experiments. The analysis results indicated that the crack emergence location and fatigue life obtained from the simulation were in agreement with the experimental results.

The bolter miner is a critical piece of equipment in the rapid set of tunneling equipment, and the load generated during coal cutting may lead to excessive vibration of the equipment and reduce its reliability. In order to reduce the vibration response of the bolter miner, this paper proposes the installation of a dynamic vibration absorber (DVA) inside the cutting arm of the bolter miner. A five-degree-of-freedom dynamics model was developed, and the cutting part was regarded as two rigid bodies flexibly connected by a rotating spring. The model's accuracy was verified based on the field test results, and the error was within 7%. It was found that the cutting caused the first-order modal vibration, and the DVA was placed in the cavity of the cutting arm to control the modal vibration of this order. To minimize the vibration, a coupled dynamics model between the DVA and bolter miner was developed, and the DVA parameters were optimized. The results showed that the acceleration RMS and peak values of the cutting part were reduced by 12% and 30.1%, respectively; the acceleration RMS and peak values of the main frame were reduced by 6.5% and 17%, respectively, and the fatigue life of the cutting arm was increased by 34.2%. [ABSTRACT FROM AUTHOR]

The Sichuan Basin and the Songpan‐Ganze terrane, separated by the Longmen Shan fold‐and‐thrust belt (the eastern margin of the Tibetan Plateau), are two main Triassic depositional centres, south of the Qinling‐Dabie orogen. During the Middle–Late Triassic closure of the Paleo‐Tethys Ocean, the Sichuan Basin region, located at the western margin of the Yangtze Block, transitioned from a passive continental margin into a foreland basin. In the meantime, the Songpan‐Granze terrane evolved from a marine turbidite basin into a fold‐and‐thrust belt. To understand if and how the regional sediment routing system adjusted to these tectonic changes, we monitored sediment provenance primarily by using detrital zircon U‐Pb analyses of representative stratigraphic samples from the south‐western edge of the Sichuan Basin. Integration of the results with paleocurrent, sandstone petrology and published detrital zircon data from other parts of the basin identified a marked change in provenance. Early–Middle Triassic samples were dominated by Neoproterozoic (~700–900 Ma) zircons sourced mainly from the northern Kangdian basement, whereas Late Triassic sandstones that contain a more diverse range of zircon ages sourced from the Qinling, Longmen Shan and Songpan‐Ganze terrane. This change reflects a major drainage adjustment in response to the Late Triassic closure of the Paleo‐Tethys Ocean and significant shortening in the Longmen Shan thrust belt and the eastern Songpan‐Ganze terrane. Furthermore, by Late Triassic time, the uplifted northern Kangdian basement had subsided. Considering the eastward paleocurrent and depocenter geometry of the Upper Triassic deposits, subsidence of the northern Kangdian basement probably resulted from eastward shortening and loading of the Songpan‐Ganze terrane over the western margin of the Yangtze Block in response to the Late Triassic collision among Yangtze Block, Yidun arc and Qiangtang terrane along the Ganze‐Litang and Jinshajiang sutures. [ABSTRACT FROM AUTHOR]

Hedyotis diffusa Willd (HDW) is a major component frequently used in Traditional Chinese Medicine for the clinical treatment of colorectal cancer (CRC) and its associated drug resistance. However, the underlying mechanism of HDW circumventing drug resistance of cancer cells remains to be elucidated. Cancer cell resistance to apoptosis and activation of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway have been implicated as major factors in the acquired resistance to chemotherapeutic anti-cancer drugs. The present study investigated the effect and mechanisms of action of ethanol extract of Hedyotis diffusa Willd (EEHDW) on the proliferation and apoptosis of CRC 5-fluorouracil (5-FU) resistant (HCT-8/5-FU) cells. CRC HCT-8/5-FU cell viability following treatment with EEHDW was determined using MTT and colony formation assay. In addition, Annexin V/propidium iodide staining with flow cytometry analysis and 4',6-diamidino-2-phenylindole staining were used to determine the apoptosis of drug-resistant cancer cells following treatment with EEHDW. The mRNA and protein expression levels of B cell leukemia/lymphoma (Bcl-2), Bcl-2 associated X (Bax), cyclin dependent kinase 4 (CDK4), cyclin D1 and p21 were evaluated using reverse transcription-polymerase chain reaction and western blot analysis, respectively. Furthermore, activation of the PI3K/AKT signaling pathway and expression of phosphatase and tensin homolog (PTEN), PI3K, AKT and phosphorylated (p)-AKT were determined. EEHDW significantly reduced cell viability, inhibited cell colony formation and promoted apoptosis of HCT-8/5-FU cells. Furthermore, EEHDW significantly downregulated the expression of Bcl-2, cyclin D1 and CDK4 and upregulated the expression of Bax and p21. In addition, EEHDW inhibited the activation of the PI3K/AKT pathway by increasing expression of PTEN and suppressing the expression of PI3K and p-AKT. The present study provided the first direct evidence that EEHDW may overcome drug-resistance in human CRC cells by inhibiting PI3K/AKT signaling pathway and provides a basis for the improved therapeutic use of HDW in the clinical treatment of cancer. [ABSTRACT FROM AUTHOR]

Metastasis is one of the most aberrant behaviors of cancer cells. Patients with cancers, including colorectal cancer (CRC), have a higher risk of tumor recurrence and cancer-related mortality once metastasis is diagnosed. Existing treatment strategies fail to cure cancer mostly due to the onset of metastasis. Therefore, metastasis remains a challenge in cancer treatment. Some complementary and alternative medical therapies using traditional Chinese medicine have been demonstrated to be clinically effective in cancer treatment. Scutellaria barbata D. Don (SB) is a promising medicinal herb. It was previously reported that the ethanol extract of SB (EESB) is able to promote apoptosis, and inhibit cell proliferation and angiogenesis in human colon cancer cells. However, the anticancer effect of SB and the underlying mechanism require further investigation, particularly its role against metastasis. To further elucidate the antimetastatic effect of SB, MTT and Transwell assays were used in the present study to evaluate the effect of EESB on the proliferation, migration and invasion of the CRC cell line HCT-8. In addition, western blot analysis was performed to detect the expression of matrix metalloproteinases (MMPs), cadherins and other metastasis-associated proteins. EESB significantly reduced HCT-8 cell viability and attenuated the migration and invasion ability of HCT-8 cells in a dose-dependent manner. In addition, EESB decreased the expression of MMP-1, MMP-2, MMP-3/10, MMP-9 and MMP-13, and proteins in the phosphoinositide 3-kinase (PI3K)/AKT and transforming growth factor (TGF)-β/Smad pathways, but not the epithelial-mesenchymal transition (EMT)-related factors E-cadherin and N-cadherin. In conclusion, the results suggested that SB inhibits CRC cell metastasis via the suppression of PI3K/AKT and TGF-β/Smad signaling pathways, which may represent a mechanism by which SB exerts an anticancer effect.