Background Transforming growth factor-beta 1 (TGF- beta 1) protein may be multifunctional and related to the development of fibrosis, induction of apoptosis, extracellular signaling and inhibition of ...proliferation in response to radiation-induced DNA damage. Several studies have investigated associations between single nucleotide polymorphisms (SNPs) in the TGFB1 gene and risk of late radiation-induced injury of normal tissue, but the conclusions remain controversial. Methods We searched three electronic databases (i.e., MEDLINE, EMBASE and EBSCO) for eligible publications and performed a meta-analysis assessing the association of three commonly studied SNPs in TGFB1 (i.e., rs1800469, rs1800470 and rs1800471) with risk of late radiation-induced injury of normal tissue. Results We finally included 28 case-only studies from 16 publications on aforementioned SNPs in TGFB1. However, we did not find statistical evidence of any significant association with overall risk of late radiotherapy toxicity in the pooled analysis or in further stratified analysis by cancer type, endpoint, ethnicity and sample size. Conclusions This meta-analysis did not find statistical evidence for an association between SNPs in TGFB1 and risk of late radiation-induced injury of normal tissue, but this finding needs further confirmation by a single large study.
Formation paraffin deposits cause serious productivity damage during the process of oil production. As an effective, economical and environmentally friendly organic solvent, CO2 has many advantages ...in removing formation paraffin deposits. In this paper, the mechanism of action for CO2-mediated removal of formation paraffin deposits is analysed. An indoor simulation of CO2-mediated removal of formation paraffin deposits is conducted. The feasibility of removing formation paraffin deposits by CO2 is investigated and the effect of injection parameters on plug removal efficiency is discussed. The experimental results show that CO2 adsorption-induced swelling and paraffin thermal expansion are the main factors that facilitate CO2-mediated removal of formation paraffin deposits. Plug removal using CO2 requires a long injection time. As the injection temperature increases, plug removal efficiency increases. As the injection pressure increases, plug removal efficiency first increases and then decreases, which allows for determination of the optimal injection pressure.
•We propose a new method of removing formation paraffin deposits by injecting CO2.•We discuss the mechanisms of CO2-mediated removal of formation paraffin deposits.•We carry out an experiment of the CO2-mediated removal of paraffin deposits.
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