An effective, value-added use of the large amounts of olefinic compounds produced in the processing of petroleum, aside from ethylene and propylene, has been a long outstanding challenge. Here, we developed a novel heterogeneous polymerization method, beyond emulsion/dispersion/suspension, termed self-stabilized precipitation (2SP) polymerization, which involves the nucleation and growth of nanoparticles (NPs) of a well-defined size without the use of any stabilizers and multifunctional monomers (crosslinker). This technique leads to two revolutionary advances: (1) the generation of functional copolymer particles from single olefinic monomer or complex olefinic mixtures (including C4/C5/C9 fractions) in large quantities, which open a new way to transform huge amount of unused olefinic compounds in C4/C5/C9 fractions into valuable copolymers, and (2) the resultant polymeric NPs possess a self-limiting size and narrow size distribution, therefore being one of the most simple, efficient, and green strategies to produce uniform, size-tunable, and functional polymeric nanoparticles. More importantly, the separation of the NPs from the reaction medium is simple and the supernatant liquid can be reused; hence this new synthetic strategy has great potential for industrial production.
Background: Colorectal cancer (CRC) is one of the most common malignant cancers globally. Circular RNAs (circRNAs) have been implicated in the development of CRC. In this paper, we set to explore the precise action of circ_0067835 in CRC progression and radioresistance. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to evaluate the expression of circ_0067835, microRNA-296-5p (miR-296-5p) and insulin-like growth factor 1 receptor (IGF1R). Western blot was used to measure the level of IGF1R protein. Cell proliferation, cell cycle distribution and apoptosis were determined by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry and caspase-3 activity assays, respectively. The direct relationship between miR-296-5p and circ_0067835 or IGF1R was verified by dual-luciferase reporter assays. Additionally, in vivo assays were applied to confirm the role of circ_0067835 in vivo. Results: Exosomal circ_0067835 was upregulated in the serum of CRC patients after radiotherapy. Exosome-mediated circ_0067835 knockdown repressed cell proliferation, cell cycle progression, and enhanced cell apoptosis and radiosensitivity in vitro. Circ_0067835 sponged miR-296-5p to regulate IGF1R expression in CRC cells. Moreover, the knockdown of circ_0067835 regulated CRC cell behaviors by up-regulating miR-296-5p and downregulating IGF1R in vitro. Furthermore, circ_0067835 knockdown diminished tumor growth and promoted cell radiosensitivity in vivo. Conclusion: Circ_0067835 knockdown suppressed CRC progression and enhanced CRC cell radiosensitivity partially by the miR-296-5p/IGF1R axis. The findings established a rationale that targeting circ_0067835 might be a promising point for improving CRC treatment.
In the production process, the asphaltene precipitation (AP) and deposition can not only inflict damage on reservoir stratum but also lead to the shut-in of well and incur the extra cost of remediation. In this study, the phase behavior of asphaltenes in live oil under high-temperature and high-pressure conditions were determined by using a modified solid (asphaltene) deposition laser detection apparatus. The test accuracy was greatly improved due to the increase of the laser power. The phase behavior of asphaltenes in live oil which characterized by the heavy components and dark color was evaluated. The oil sample was from Fahliyan oilfield in Iran, which is suffering big AP problem. In addition, the values of the bubble point pressure (BPP) obtained by this apparatus have proven to be well matched with that measured by constant composition experiment (CCE) test. Moreover, the equation of state (EOS) of the asphaltene and crude oil obtained by the fitting curve can be used to further optimize the mathematical prediction model. Furthermore, the phase diagram is completed in conjunction with the P-T curve to predict the deposition location of asphaltene in the well. For the example well, the predicted results at the depth of 1930 m are almost comparable to the results of the actual production process at the depth of 1845 m, which only has a difference of 2.1%. Accordingly, the addition of chemical inhibitors is recommended as an effective method to reduce the risk of AP in the example well.
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