Research Progress of Intelligent Polymer Plugging Materials.

Intelligent polymers have become the focus of attention worldwide. Intelligent polymer materials through organic synthesis methods are used to make inanimate organic materials become "feeling" and "sentient". Intelligent polymer materials have been applied in actual engineering production, and they are becoming a new research topic for scientists in various fields and countries, especially in the areas of drilling and plugging. The development of intelligent polymer materials can provide new solutions and technical means for drilling and plugging. Unlike traditional plugging materials, intelligent polymer plugging materials can cope with environmental changes. They have the characteristics of a strong target, good plugging effect, and no damage to the reservoir. However, there are currently no reviews on intelligent polymer plugging materials in the drilling field, so this paper fills that gap by reviewing the research progress of intelligent polymer plugging materials. In addition, this paper describes the mechanism and application status of intelligent polymer shape-memory polymers, intelligent polymer gels, intelligent polymer membranes, and intelligent polymer bionic materials in drilling and plugging. It is also pointed out that some intelligent polymer plugging materials still have problems, such as insufficient toughness and a poor resistance to salt and high temperature. At the same time, some suggestions for future research directions are also presented for reference.

Does bank competition curb corporate pollution emissions? Evidence from the geographical location of bank branches.

This study interprets enterprise pollution reduction from the perspective of the financial market. Using data on Chinese industrial enterprises, this paper tests the impacts of bank competition on enterprise pollution emissions. The findings show that bank competition has a significant total effect and technique effect on pollutant reduction. Bank competition reduces pollutant emissions by easing financing constraints, increasing the implementation of internal pollution control, and improving the efficiency of bank credit resource allocation. Further research shows that both bank type and bank branch level could moderate the pollution reduction effects and such effects vary a lot under different environmental regulation intensities. We expand the relevant literature on the economic consequences of banking competition and have certain theoretical and practical reference significance for the future reform of the banking industry.

Construction of a stable genetically engineered rhamnolipid-producing microorganism for remediation of pyrene-contaminated soil.

One rhamnolipid-producing bacterial strain named Pseudomonas aeruginosa BSFD5 was isolated and characterized. Its rhlABRI cassette including necessary genes for rhamnolipid synthesis was cloned and transformed into the chromosome of P. putida KT2440 by a new random transposon vector without introducing antibiotic-resistance marker, generating a genetically engineered microorganism named P. putida KT2440-rhlABRI, which could stably express the rhlABRI cassette and produce rhamnolipid at a yield of 1.68 g l(-1). In experiments using natural soil, it was shown that P. putida KT2440-rhlABRI could increase the dissolution of pyrene and thus promote its degradation by indigenous microorganisms. P. putida KT2440-rhlABRI thus demonstrated potential for enhancing the remediation of soils contaminated with polycyclic aromatic hydrocarbons.

Effects of resveratrol on the expression and DNA methylation of cytokine genes in diabetic rat aortas.

This paper studies the expression of proinflammatory cytokines such as IL-1ß, IL-6, TNF-α, and IFN-γ and anti-inflammatory cytokines such as IL-10 in diabetic rat aortas, the effects of resveratrol on these cytokines, and the potential epigenetic mechanisms involved. The experiment was performed on rats divided into four groups: normal group (NC), normal interventional group (NB), diabetic group (DM), and diabetic interventional group (DB). The NB and DB groups were treated with resveratrol. After more than 3 months, the rats' aortas were removed and analyzed for cytokines by using immunohistochemistry, Western blotting, real-time PCR, and methylation-specific PCR. Histological localization of these cytokines was mainly found in the arterial intima of diabetic rats. The protein and mRNA expression levels of IL-1ß, IL-6, TNF-α, and IFN-γ were significantly higher in the DM group than in the NC group (p < 0.05), whereas in the resveratrol-treated groups (NB and DB), the levels were relatively lower than those in the corresponding groups. The DM group showed reduced levels of DNA methylation at the specific cytosine phosphate guanosine sites of IL-1ß, IL-6, TNF-α, and IFN-γ, relative to those in the NC group (p < 0.01), and these levels were increased by resveratrol. In contrast, IL-10 was dramatically methylated and showed decreased expression in response to high glucose, and resveratrol reversed this effect. These results demonstrate that the inflammatory response is involved in diabetic macroangiopathy. Resveratrol inhibits the expression of proinflammatory cytokines and thus may have a protective effect on the aorta in hyperglycemia. Thus, DNA methylation, an epigenetic gene silencing signal, may be responsible for these two phenomena.

Diverse endophytic nitrogen-fixing bacteria isolated from wild rice Oryza rufipogon and description of Phytobacter diazotrophicus gen. nov. sp. nov.

Twenty-three nitrogen-fixing bacteria were isolated from surface-sterilized stems and roots of wild rice Oryza rufipogon. Four clusters were defined among these bacteria by SDS-PAGE protein patterns and further confirmed by IS-PCR finger-printing analysis. Phylogenetic analysis of 16S rRNA gene sequences showed that the representative strains LS 8 and LS 18 of cluster II formed a monophyletic group sharing 94.0-97.3% similarities with defined enterobacterial species within the genera Salmonella, Citrobacter, Pantoea, Klebsiella, and Enterobacter. DNA-DNA hybridization, physiological, biochemical tests, and cell morphology also revealed that these strains could be differentiated from the related enterobacterial species. Based upon these results, we propose Phytobacter diazotrophicus gen. nov., sp. nov. to the bacterial group represented by strains LS 8 and LS 18. The type strain is LS 8(T) (=DSM 17806(T) = LMG 23328(T) = CGMCC 1.5339(T)). The DNA G+C content of strain LS 8(T) is 58.6 +/- 0.5 mol%.