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Abnormal wear of stitch wires due to interference poses a serious threat to railway safety. To avoid this scenario, the concept of the dynamic envelope of the stitch wire was proposed, accompanied by an interference check method. A multi-node beam model of the stitch wire was established using the finite element method, employed to simulate the pantograph and catenary system, and validated by field test. The dynamic behaviour of the stitch wire was studied, and the concept of dynamic envelope was introduced. Moreover, factors affecting this envelope were analysed, and an interference check method was proposed. Results demonstrate that, the vibration of the stitch wire mainly occurs in the vertical direction and intensifies with increasing speed. Its vertical vibration increases from 70 mm to 137 mm as the train speed goes from 300 km/h to 400 km/h. Cantilever assembly errors and dropper installation issues are the main causes for the abnormal wear of stitch wires. A 100 mm assembly error reduces the clearance from 67 mm to 14 mm, while a 2 m dropper installation error eliminates the clearance entirely. This study provides valuable insights for enhancing the safety of catenary system. [ABSTRACT FROM AUTHOR]

Stitch wire is the key component in high-speed railway catenary. During the construction and operation of the catenary, tension changes can lead to fracture of the stitch wire. This study proposed a simulation method considering the structure and stress distribution of stitch wire to reveal the effect of tension changes on the fatigue life. Dynamic simulation model at a speed of 300 km/h was constructed to obtain the vibration load. A refined model of stitch wire was used to simulate the contact between the structures. Finally, the fatigue life of stitch wire was calculated when the tension changes by analysing the stress distribution under vibration. Results demonstrate that the lifting effect of the pantograph during operation causes vertical vibrations of stitch wire, and the stress concentration position is located at the connection with its clamp. As the tension increases form 2.0 kN to 5.0 kN, the range of vibration angle at the clamp decreases from 2.73° to 1.33°, and fatigue life increases from 1.36 x 106 to 8.76 x 106. The proposed method provides an accurate approach to simulate the load and fatigue life of stitch wire under real working conditions. [ABSTRACT FROM AUTHOR]

High-throughput sequencing and traditional microbial culturing were used to analyze the effects of the addition of free or immobilized degrading bacteria on the soil physicochemical properties and microbial community structure by simulating the pollution of 2, 2', 4, 4'-tetrabromo diphenyl ether (BDE-47), and to measure the degradation rates. The results showed that (1) The soil physicochemical properties including pH, organic matter, total nitrogen, total phosphorus and total potassium were not significantly affected by the addition of BDE-47, free or immobilized bacteria; (2) Proteobacteria, Acidobacteria, andActinobacteria were the dominant phyla in the simulation systems, of which the relative abundance of Proteobacteria and Acidobacteria decreased whereas that of Actinobacteria increased through the simulation. Firmicutes was dominant in the simulation system B. Seven phyla, including Bacteroidetes, Gemmatimonadetes, and Nitrospirae, were shared by all simulation systems. The free degrading strain adapted well to the simulation system, and the cell count increased from (5.0 ± 0.1) x 104 Colony-forming unit (CFU) /g to (1.0 ± 0.2) x 105 CFU/g at the end of the simulation; (3) The degradation of BDE-47 occurred in the original soil used for the simulation, while the addition of the free degrading strain promoted the degradation of BDE-47 at a rate of 39.77%. The addition of the immobilized strain also promoted the degradation of BDE-47, but only at a rate of 36.94%, slightly lower than that of the free strain. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the effects of different concentrations of heparin catheter- sealing solution for implantable venous access ports (VAPs) on D-dimers (D-D) in older cancer patients. PATIENTS AND METHODS: A total of 208 older cancer patients who received intravenous chemotherapy for the first time were randomly divided into four groups: the normal saline group, the low concentration heparin group (25 U/ml), the medium concentration heparin group (50 U/ml), and the high concentration heparin group (75 U/ml), with 52 patients in each group. VAPs were sealed by the positive pressure technique every day before and after perfusion, as well as at the end of a course of chemotherapy when the butterfly needle was removed. The patients were followed-up for three courses of chemotherapy, and comparisons of the clinical effects were conducted. RESULTS: Before treatment and at the end of follow-up, no significant differences among groups were found in platelet count, prothrombin time, thrombin time, or activated partial thromboplastin time (p>0.05). At the end of follow-up, the high concentration heparin group had reduced fibrinogen (FIB) and increased D-D compared with the other groups, and the differences were statistically significant (p<0.05). The other three groups showed no significant differences in FIB or D-D before treatment or at the end of follow-up (p>0.05). The high concentration heparin group had higher local bleeding rate, while the saline group had higher partial and complete prevalence of blockage compared with the other groups. The differences were statistically significant (p<0.05). CONCLUSIONS: 25-50 U/ml heparin catheter- sealing solution had little effect on blood circulation and coagulation. Additionally, it did not increase the risk of local bleeding or thrombotic blockage. [ABSTRACT FROM AUTHOR]

Lymphatic metastasis is an independent prognostic factor for surgical prognosis of patients with hilar cholangiocarcinoma (HCCA) . Lymph node dissection is an important content of radical resection of HCCA, but there are still many disputes about the definition, scope and dissection numbers of intraoperative lymph node dissection. There has been a lot of research being done at home and abroad in recent years focusing on the above problems, and novel insights have also been proposed.According to the current view, routine skeletal dissection of lymph nodes in the duodenum ligament of liver, the common hepatic artery, and the posterior part of the duodenum of pancreas head (the 12(th) group, the 8(th) group and the 13(th) group) during operation can bring significant survival benefits to patients with HCCA. However, it is still not clear whether the dissection of peripheral lymph node in truncus coeliacus, aorta abdominalis, and venae cava inferior during operation can bring survival benefits to HCCA patients during operation. Properly increasing the number of lymph node dissection during operation can not only significantly improve the survival prognosis of the patients of HCCA with stage N0, but also improve the detection rate of positive lymph nodes and obtain enough information for the stage of the disease. However, the excessive increase of total lymph node count is not only difficult to achieve in practice, but may also lead to an increase in the incidence of postoperative complications. Therefore, further investigation is needed in intraoperative lymph node dissection of HCCA.

Aim: To investigate the chemical constituents from the roots of Diuranthera inarticulata Wang et K. Y. Lang., Methods: The compounds were isolated with silica gel column chromatography and their structures were identified on the basis of spectral data and TLC with authentic samples., Results: From the methanolic extracts of the roots of Diuranthera inarticulata, ten compounds were obtained and nine of them were identified as chloromaloside A (III), diuranthoside A (IV), diuranthoside B (V), diuranthoside F (VI), diuranthoside G (VII), 2 alpha, 3 alpha, 19 alpha-trihydroxy-urs-12-en-28-oic acid (VIII), 3,6,7,3',4'-pentamethoxy flavone (IX), gitogenin (X) and daucosterol (XI). III-VI showed inhibition of growth with the yeast, Candida albicans. III, IV and VI also showed inhibition of growth with fungus, Aspergillus niger, in the test of antibacterial activity., Conclusion: All of these compounds were isolated from this plant for the first time. Among them, VI and VII are new steroidal saponins.