32 research outputs found

    Investigation of Molecular Structure and Thermal Properties of Thermo-Oxidative Aged SBS in Blends and Their Relations

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    Tri-block copolymer styrene–butadiene (SBS) is extensively applied in bituminous highway construction due to its high elasticity and excellent weather resistance. With the extension of time, tri-block structural SBS automatically degrades into bi-block structural SB- with some terminal oxygen-containing groups under the comprehensive effects of light, heat, oxygen, etc. In this paper, the effects of aging temperature, aging time and oxygen concentration on the molecular structure of thermo-oxidative aged SBS were mainly investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), and the correlation between oxygen-containing groups and thermal properties (TG–DTG) was further discussed. The FTIR and XPS results show that rapid decomposition of SBS will occur with increments of aging temperature, aging time and oxygen concentration, and a large number of oxygen-containing groups such as –OH, C=O, –COOH, etc. will be formed during thermo-oxidative aging. In short-term aging, changes in aging temperature and oxygen concentration have a significant impact on the structural damage of SBS. However, in long-term aging, it has no further effect on the molecular structure of SBS or on increasing oxygen concentration. The TG and DTG results indicate that the concentration of substances with low molecular weight gradually increases with the improvement of the degree of aging of the SBS, while the initial decomposition rate increases at the beginning of thermal weightlessness and the decomposition rate slows down in comparison with neat SBS. From the relation between the XPS and TG results, it can be seen that the initial thermal stability of SBS rapidly reduces as the relative concentration of the oxygen-containing groups accumulates around 3%, while the maximum decomposition temperature slowly decreases when the relative concentration of the oxygen-containing groups is more than 3%, due to the difficult damage to strong bonds on the molecular structure of aged SBS

    Broadcasting Policy, Creative Compliance, and the Myth of Civil Society in China

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    This paper looks at arguments framing civil society debates and questions the usefulness of civil society models in understanding how media policy is made and implemented in China. The key argument is that viewing the state-society relationship in China through a Western optic obviates the distinctive differences between the autonomous civil society of liberal-democracies and Chinese social relations. This does not mean that civil society is a redundant concept. It can be usefully applied to describe economically driven political and social change in China. However, its capacity to explain how cultural and media policy is formulated is limited

    Diagnostic Value of Serum miR-182, miR-183, miR-210, and miR-126 Levels in Patients with Early-Stage Non-Small Cell Lung Cancer

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    <div><p>Blood-circulating miRNAs could be useful as a biomarker to detect lung cancer early. We investigated the serum levels of four different miRNAs in patients with non-small cell lung cancer (NSCLC) and assessed their diagnostic value for NSCLC. Serum samples from 112 NSCLC patients and 104 controls (20 current smokers without lung cancer, 23 pneumonia patients, 21 gastric cancer patients, and 40 healthy controls) were subjected to Taqman probe-based quantitative reverse transcription–polymerase chain reaction (RT-PCR). The data showed that the serum levels of miR-182, miR-183, and miR-210 were significantly upregulated and that the miR-126 level was significantly downregulated in NSCLC patients, compared with the healthy controls. Further receiver operating characteristic (ROC) curve analysis revealed that the serum miR-182, miR-183, miR-210, or miR-126 level could serve as a diagnostic biomarker for NSCLC early detection, with a high sensitivity and specificity. The combination of these four miRNAs with carcinoembryonic antigen (CEA) further increased the diagnostic value, with an area under the curve (AUC) of 0.965 (sensitivity, 81.3%; specificity, 100.0%; and accuracy, 90.8%) using logistic regression model analysis. In addition, the relative levels of serum miR-182, miR-183, miR-210, and miR-126 could distinguish NSCLC or early-stage NSCLC from current tobacco smokers without lung cancer and pneumonia or gastric cancer patients with a high sensitivity and specificity. Data from the current study validated that the four serum miRNAs could serve as a tumor biomarker for NSCLC early diagnosis.</p></div

    Serum levels of miRNAs in NSCLC or early-stage NSCLC patients versus smokers, pneumonia patients, and gastric cancer patients.

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    <p>The serum levels of miR-182, miR-183, miR-210, and miR-126 were assessed in 112 NSCLC patients, 20 current smokers, 23 pneumonia patients, and 21 gastric cancer patients using qRT-PCR. U6 snRNA was used as the reference. *<i>P</i> < 0.05 between groups using the Mann-Whitney test.</p

    ROC curves to assess the value of serum miRNA and CEA levels in 112 NSCLC patients compared to 23 pneumonia patients.

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    <p>The <i>P</i> values of serum miR-182, miR-183, miR-210, miR-126, and CEA as well as the predictive value of logistic regression were 0.0061, 0.0259, 0.0350, 0.0002, 0.1914, and 0.0031, respectively.</p
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