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Fibrosis is the result of the abnormal accumulation of the extracellular matrix and ineffective clearance of fibroplasia. CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) are immunosuppressive lymphocytes that are highly expressed in the fibrotic tissues and peripheral blood of patients with cirrhosis or hepatocellular carcinoma. The role of Tregs in the progression of liver fibrosis is not well understood. Our experiments reveal that abundant of Tregs was scattered around sites of fibroplasia. Conversely, the depletion of Tregs promoted the resolution of liver fibrosis. As a consequence of Tregs depletion, the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) was altered; mmp9 and timp1 were reduced, whereas mmp2 and mmp14 were enhanced. The mmp9/timp1, mmp13/timp1, and mmp14/timp2 ratios were significantly increased in association with fibrosis resolution. Kupffer cells (KCs) are the main source of MMP. We observed that when KCs were cocultured with Tregs, the Tregs were able to inhibit MMP expression of KCs even at a low ratio; and anti-transforming growth factor-β (TGF-β) significantly reversed the inhibition of Tregs on MMP. Meanwhile, we also found that after Tregs depletion, TGF-β levels decreased in the mice liver, unlike in fibrosis. Furthermore, double depletion of both KCs and Tregs did not cause fiber resolution in mice. Thus, our results demonstrate that the persistence of liver cirrhosis is maintained by increased Tregs in the sites of fibroplasia and the subsequent regulation of the MMP/TIMP balance and that the suppression of KC-mediated MMP expression contributed to the regulatory process.

In order to obtain the details of the moon dust particles dynamic trajectory on the moon, and reduce the damage of the moon dust particles to the aircraft and astronauts, a particle dynamic trajectory measurement method was proposed, based on the asynchronous delay method and the light field camera. During the long exposure time,the trajectory of the particles recorded was used to observe the particles motion state. This topic firstly used a common Charge Coupled Device(CCD) camera to build a two-dimensional measurement system for particle motion trajectory measurement. This method did not require complex image processing algorithms,and used simple superposition of images realized the particle motion trajectory measurement,the measurement system error is 0.28%. It lays the foundation for the three-dimensional measurement of particle trajectory by using the light field camera later.

In order to solve the problem of underwater image quality degradation in the process of ship navigation，the image contrast enhancement technology and image enhancement algorithm based on polarization imaging were studied. In this technique, different angle fusion images are decomposed into multi-scale Pyramid image sequences based on polarization information. Gaussian convolution and Laplacian Pyramid algorithm are used for image fusion. Compared with the wavelet transform image fusion algorithm, it can be concluded that the SNR and SSIM values of underwater images are improved obviously. Experiments show that with attenuation coefficient of 2.1, the underwater imaging distance of the underwater polarization system reaches 6 m in the seawater environment, can clearly identify the objects and their characteristics in the water, and the system operates stably.

The increased copper ion (Cu2+) concentrations in aquatic ecosystem significantly influence the environmental quality and ecosystem safety, while information on the Cu2+ biotoxicity to aquatic microorganisms and the models for biotoxicity prediction are still unclear. In this study, the toxicities of Cu2+ to Chlorella vulgaris under different environmental conditions (e.g., Na+, K+, Ca2+, Mg2+, pH, and dissolved organic matter) were explored, with the experimental results in comparison with those predicted by the biotic ligand model (BLM). Results showed that increased Cu2+ concentration caused obvious toxicities to C. vulgaris, whereas the commonly occurring cations and dissolved organic matters can protect the metabolism system of C. vulgaris. The presence of extracellular polymeric substances (EPS) matrix can alleviate the biotoxicity via increasing the surface biosorption but decreasing cell internalization of Cu2+ in C. vulgaris. Due to the presence of EPS matrix, the experimental biotoxicity results under each condition were significantly lower than those predicted by the BLM model, which was thus modified via taking the EPS matrix as the supplement of allochthonous organic matters. After that, the modified BLM was characterized with a higher degree of precision and can be used in natural waters for biotoxicity prediction. Results obtained can enhance our insights into the ecological effects and biotoxicity prediction of heavy metals in natural aquatic ecosystems. [ABSTRACT FROM AUTHOR]