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Natural pozzolan is a promising supplementary cementitious material for hydraulic concrete due to the pozzolanic effect, especially in the area where fly ash is scarce. In this paper, the physical properties of pozzolan were evaluated. The effects of pozzolan fineness and content on the microstructure, compressive strength, and early-age chemical shrinkage of pozzolan blended cement pastes were investigated. The results showed that the addition of pozzolan decreased the compressive strength of hardened cement pastes. The pozzolanic reactivity was closely related to the fineness of pozzolan, and higher pozzolan content led to lower strength. X-ray diffraction (XRD) and thermogravimetric (TG) analysis proved that Ca(OH)2 was consumed by reacting pozzolan, forming new calcium silicate hydrated (C-S-H). Besides, the addition of pozzolan caused the increase in porosity, which was reflected by the increase in macro-pores content. The chemical shrinkage of cement pastes was mainly determined by the hydration rate of cement, so the early-age chemical shrinkage was notably reduced after adding pozzolan due to its lower reactivity than cement clinker. In addition, finer pozzolan particles resulted in less macro-defects in the cement matrix, which enhanced the deformation resistance of hardened cement paste, and thus the chemical shrinkage was also decreased. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the efficacy of combined treatment with vacuum sealing drainage (VSD) and recombinant human epidermal growth factor (rhEGF) for refractory wounds in the extremities, and its effect on serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-2. Ninety-eight patients with refractory wounds in the extremities were recruited and randomly divided into the combined treatment group (underwent VSD and rhEGF treatment) and control group (underwent VSD only) with 49 cases each. Formation of granulation tissue on the wound surface was assessed and scored. The wound healing rate was calculated after 1 week of treatment, and the time of complete healing was recorded. Serum levels of IL-6, IL-2, and TNF-α were measured using enzyme-linked immunosorbent assay. After 1 week of treatment, granulation tissue formation on wound surfaces was significantly improved (p<0.05) compared with that before treatment in both groups. Moreover, granulation tissue formation on wound surfaces was superior in the combined treatment group than in the control group (p<0.05). The wound healing rate was 63.50±4.75% in the combined treatment group and 31.79±3.52% in the control group, and the difference was statistically significant (p<0.05). The time of complete healing was 15.11±2.24 days in the combined treatment group and 19.63±2.76 days in the control group, and the difference was statistically significant (p<0.05). The serum levels of IL-6, IL-2, and TNF-α, in the two groups were significantly lower than those before treatment (p<0.05). Moreover, the levels in the combined treatment group were significantly lower than those in the control group (p<0.05). In conclusion, combined treatment with VSD and rhEGF reduced inflammation and shortened the time of complete healing of refractory wounds in the extremities. Measurement of the levels of related inflammatory factors provided a reference for the prognosis of refractory wounds. [ABSTRACT FROM AUTHOR]

Bermudagrass (Cynodon dactylon(L.) Pers.) is a widely used turfgrass in tropical, subtropical and warm-temperate regions in the world. It is a salinity-tolerant plant, but much genetic variation exists among its genotypes. Genetic diversity has been shown to exist from a morphologic level to a molecular level among Chinese natural bermudagrass germplasm resources; however, the extent of variation in their salinity tolerance has remained unclear. We conducted greenhouse hydroponic and sand culture experiments to evaluate the variation in salinity tolerance of natural bermudagrass germplasm resources obtained from their main areas of distribution in China and treated at a 33 dS m−1salinity level for three weeks. Compared with non-saline controls, salinity stress significantly decreased shoot clipping weight (46.5% and 44.2%) and increased leaf firing (41.1% and 37.6%) in hydroponic and sand culture experiments, respectively, across all genotypes. However, significant genetic variations in relative leaf firing percentage (RLF) and relative shoot weight (RSW) were found among genotypes in both experiments, and their coefficients of variation ranged from 25.5% to 41.6%, indicating that considerable variation exists in the salinity tolerance of Chinese natural bermudagrass germplasm resources. Shoot Na+concentrations increased under salinity stress for all genotypes in both experiments. However, significant genetic variations were also found in shoot Na+concentrations. Salinity tolerance in bermudagrass genotypes was found to be significantly negatively correlated with shoot Na+concentrations in both experiments. Using a cluster analysis of RLF and RSW data, all genotypes were classified into four groups with different salinity tolerances. The results of our evaluation indicate that there is much potential for improving salinity tolerance among Chinese natural bermudagrass cultivars. [ABSTRACT FROM AUTHOR]