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The six elements of lithium, beryllium, niobium, tantalum, rubidium and cesium in rare polymetallic ores often coexist together. Beryllium minerals are mostly difficult to be completely dissolved by acid, while niobium and tantalum are easy to be hydrolyzed. The accurate determination of these elements requires a variety of methods and complicated analysis process. In this paper, a method for simultaneous determination of lithium, beryllium, niobium, tantalum, rubidium and cesium in rare polymetallic ores by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) was established by investigating the holding time and the amount of extraction solution after microwave digestion. The results showed that the samples could be completely dissolved by holding for 30 min, and completely extracted by 10 mL of hydrofluoric acid (1 + 1) and 3 drops of hydrofluoric acid. The mass spectrum signals of each element showed a good linear relationship in the concentration range of 0--20 jug/mL, and the correlation coefficients (r) were above 0.999 9. The microwave digestion method and the electrothermal plate digestion method were used to determine the six rare polymetallic ores of national first-class standard substances respectively. The results showed that the determination of beryllium by the electrothermal plate digestion method was obviously low, and the determination results of each element by the microwave digestion method were within the error range of the recognized value. The detection limits were 3. 0--10. 0 jng/g, the test range was 0. 001%--4. 3%, and the relative standard deviation RSD (w=12) was 0. 32%--12. 5%. The quality parameters meet the requirements of geological and mineral experiments. [ABSTRACT FROM AUTHOR]

Objective To construct a Rb luciferase reporter gene detection system and detect the activation and inhibition levels of Rb gene, so as to screen a variety of targeted therapy drugs for tumors Choose to provide experimental basis. Method The synthetic Rb reaction original gene sequence was linked to the reporter gene vector pGL6-TA by double enzyme digestion. Site region, and transform E. coli DH5α competent cells to construct the vector pGL6-Rb-Luc. The pGL6-Rb-Luc plasmid with the correct gene sequence sequence and the control The pGL6-TA plasmid was transfected into the human renal epithelial cell line HEK293, and through the resistance gene screening, the stable expression of the Rb luciferase reporter gene can be obtained. The HEK293-Rb-Luc monoclonal cell line and the control cell line were tested by serum stimulation and CDK4/6 inhibitor Palbociclib respectively. Test system HEK293-Rb-Luc activation and inhibition. Analyze the sequence results of the carrier and compare them to determine the constructed carrier The Rb response element gene sequence in pGL6-Rb-Luc has been correctly inserted into the multi-cloning site region of the vector. HEK293-Rb-Luc cell line synchronized by serum-free culture After resuming the serum culture for 6, 12, and 24h, the activity of luciferase in the cells was significantly increased (P<0.001), and there was no significant change in the control cells. compared to In the 0nmol/LPalbociclib group, 25, 50, 75, and 100nmol/L CDK4/6 inhibitor Palbociclib made the inhibition rate of Rb activity reach 6.90%, 40.23%, 50.57%, 52.07% (P<0.05). Conclusion The Rb luciferase reporter gene detection system HEK293-RbLuc has been successfully constructed and screened, and it can effectively detect the activation level of Rb. [ABSTRACT FROM AUTHOR]

Based on immersed tunnel engineering experience from island and tunnel project of Hongkong-Zhuhai-Macao Bridge, combined with literature analysis, submerged floating tunnel (SFT) cross-section design determination method was developed in this paper. It is found: 1) the SFT conceptual cross-section design can be based on three principles, the space requirement can be comparable to that of immersed tunnel, the given formula of buoyancy-weight ratio (BWR) or residual buoyancy (RB), and the given formula of re-locatable ballast weight; 2) the weight requirement of SFT shall be much more rigorous than that of immersed tunnel; 3) for practical use, the current research-defined BWR or RB shall be further clarified and subdivided for operational target value and cross-section design-used value. [ABSTRACT FROM AUTHOR]

Background and objective Rb is an important tumor suppressor gene that regulates cell cycle progression. Rb dysfunction can lead to over proliferation of cells and lead to the occurrence of tumor. Loss or reduced Rb expression as well as over phosphorylation of Rb are important mechanisms of Rb dysfunction. The mutated epidermal growth factor receptor (EGFR) gene is an important driver gene in lung adenocarcinoma, and plays an important role in the development of lung cancer. The purpose of this study was to investigate the status of Rb in lung adenocarcinoma patients with EGFR mutations and define the clinicopathologic features. Methods 23 cases pulmonary adenocarcinoma patients with EGFR mutations were collected. The status of Rb and pRb-780, pRb-795 were determined byimmunohistochemistry. Results Loss or reduced Rb expression were detected in 16 of 23 samples (69.6%). pRb-780 and pRb-795 over-expressed were identified in 17 (73.9%) and 16 (69.6%) of 23 samples respectively. All the 23 patients had showed loss/reduced Rb expression or over-expressed Rb phosphorylation. Further analysis showed that over expression of pRb-780 and pRb-795 occurred more frequently in advanced patients. Conclusion Aberrant expressionof Rb is frequently occurred in lung adenocarcinoma patients with EGFR mutations and may be an important pathogenesis in patients with lung adenocarcinoma.

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