Search

AbstractMaleic acid (MA), hydroxyethyl methacrylate (HEMA), and 2-acrylamide-2-methylpropane sulfonic acid (AMPS) were used to create the retarder JT-1. FTIR was used to characterize the retarding agent’s structure, XPS, GPC, and TG were used to determine the polymer’s elemental composition and molecular weight, and TG was used to determine the polymer’s thermal stability. The results show that the molecule contains the desired functional groups, that the temperature at which pyrolysis began was 276 °C, and that performance stability occurred at 130 °C. The thickening curve does not exhibit a “bulge” or “step” phenomena, and the thickening time complies with high temperature pumping safety standards. Additionally, it can guarantee the development of cement’s compressive strength at low temperatures, has great temperature adaptability, and works well with the G33S water loss reducer in terms of compatibility and dispersion. The retarder molecules were found to create a layer of adsorption with a specific thickness on the surface of cement particles. This layer resulted in a reduction in the concentration of Ca2+ in the solution through complexation. As a consequence, the hydration process of the cement was delayed, leading to an extended thickening time. These results were attained by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques in the research that was done. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Naturalium Universitatis Sunyatseni / Zhongshan Daxue Xuebao is the property of Sun-Yat-Sen University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum Naturalium Universitatis Sunyatseni / Zhongshan Daxue Xuebao is the property of Sun-Yat-Sen University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heat shock protein 27 (Hsp27) is a member of the small heat shock protein family expressed at high levels to protect cells against heat shock and other conditions of stress. Hsp27 has been indicated in the regulation of inflammation signaling pathway, and Hsp27 phosphorylation is vital for efficient control of host‐defense response in early stages of lipopolysaccharide (LPS)‐stimulated inflammation. The notion that CREB‐binding protein (CBP) is involved in the regulation of two major transcription factors, nuclear factor‐κB (NF‐κB) and AP‐1, suggests that CBP, as a coactivator protein, may also play an important role in the cellular response to inflammation. Here, we explored the mechanism underlying the regulatory relationships between Hsp27 and CBP in THP‐1 cells, and found that phosphorylated Hsp27 was critical to the protein level of CBP. Furthermore, in exploring the signaling mechanisms underlying its action, we found that p38MAPK‐MK2‐Hsp27 regulated NF‐κB via CBP, which acted as a multi‐protein complex assembly scaffold. Finally, we demonstrated that phosphorylated Hsp27 reduced reactive oxygen species accumulation thereby significantly repressed LPS‐induced excessive increase of CBP. Taken together, our data demonstrated that Hsp27, in its phosphorylation state, plays a critical role in controlling LPS‐induced inflammatory response by modulating CBP. Highlights: Inhibition of Hsp27 phosphorylation decreases LPS‐induced production of early inflammatory factors.Phosphorylated Hsp27 increases CBP expression through p53 activation in LPS‐triggered early inflammation.Hsp27 phosphorylation regulates NF‐κB activation via modulating CBP protein level.Hsp27 phosphorylation down‐regulates CBP through preventing the excessive accumulation of ROS in LPS‐induced late stages of inflammation. [ABSTRACT FROM AUTHOR]

With rapid economic development and urbanization, the air pollution problem over China has drawn great attention. To explore the aerosol direct effect (ADE) over China, two simulations were conducted using WRF-Chem V3.5.1 in the summer of 2015. One was a control run (CTL) including aerosol effect and related physical and chemical processes, and the other one was a sensitivity simulation (SEN), the same as CTL except that aerosol-radiation interactions were turned off. The differences between two tests were analyzed, in particular over regions in South China (SC) and East China (EC). Results showed the following. (1) The large-scale circulation showed a strong El Niño signal, associated with cooling and wet anomalies over EC, while warming and dry anomalies over EC. (2) Due to ADE, there was a significant decrease in precipitation and an increase in AOD over SC and EC, albeit with different mechanisms. (3) In SC, ADE cooled the region reinforcing the El Niño impact and suppressing water vapor fluxes, which led to a more stable atmosphere and weakened water cycle. In EC, ADE caused vertical circulation anomalies opposing the El Niño impact. (4) ADE showed obvious land-sea difference in precipitation and shortwave radiation. [ABSTRACT FROM AUTHOR]