Effect of Fibers on the Performance of a Porous Friction Course.

In this paper, the preparation of a porous friction course (PFC) with styrene-butadiene-styrene (SBS)-modified asphalt and fibers instead of a high-viscosity-modified asphalt was investigated. The aggregate gradation B was chosen to prepare the PFC, and the optimal asphalt content in the PFC containing lignin or basalt fibers was determined to be 4.5% by the Cantabro abrasion experiment and Schellenberg draindown experiment. The freeze-thaw split experiment and immersed Marshall experiment indicated that with the addition of the fiber, the residual stability increased by 7.6 and 2.4% for the PFC with the lignin and basalt fibers, respectively, indicating that fibers can enhance the moisture damage resistance of the PFC. Furthermore, the dynamic stability increased by 17.9 and 6.0% for the PFC with the lignin and basalt fibers, respectively, indicating that fibers can significantly enhance the rutting resistance of the PFC at high temperatures. These results prove that the PFC prepared by SBS-modified asphalt and lignin/basalt fibers reaches the standard of pavement performance.

The temptin gene of the clade Lophotrochozoa is involved in formation of the prismatic layer during biomineralization in molluscs.

The biomineralization mechanism of mollusc shell has been studied for a long time, but there is a lack of understanding about the relationship between the shell formation in vitro and the signaling system in vivo. In this study, we cloned a novel shell matrix protein gene (hc-temptin), which only be characterized as a water-borne protein pheromone of molluscs in previous studies, from the freshwater mussel Hyriopsis cumingii. By bioinformatics analysis we found that temptin was a gene unique to the clade Lophotrochozoa, and it exists in all mollusc taxa except Cephalopoda. The current data supported the premise that temptin was generated in the early emergence of molluscs and that it maintained a high mutation rate to evolve relative independently. The specificity of hc-temptin expression in the mantle tissue suggests its potential to participate in biomineralization. Its sequence contained typical Ca2+ binding sites. Our experiments involving the pearl formation process, damaged shell repair process, and RNAi experiment showed that hc-temptin was a shell matrix protein that plays an important role in formation of the prismatic layer. The results of this study provided new insights about the origin of the temptin gene and its role in molluscs.

Seasonal variation of Microcystis in Lake Taihu and its relationships with environmental factors.

In order to monitor the changes of Microcystis along with temporal and spatial variations, seasonal variation of Microcystis in Lake Taihu was investigated by 16S-23S rRNA internal transcribed spacer denaturing gradient gel electrophoresis (16S-23S rRNA-ITS DGGE) and microscopic evaluation. Samples were collected quarterly at four sites (River Mouth, Meiliang Bay, Cross Area, and Lake Center) from August 2006 to April 2007. Results showed that Microcystis dominated total phytoplankton abundance at the four sites in all seasons except winter. The average annual abundance of Microcystis was relatively high at River Mouth and Meiliang Bay, reaching 81.22 x 10(6) and 61.32 x 10(6) cells/L, respectively. For temporal variations, Shannon-Wiener diversity index (H') according to DGGE profile revealed the richness of Microcystis in summer (H' = 1.375 +/- 0.034) and winter (H' = 1.650 +/- 0.032) was lower than that in spring (H' = 2.078 +/- 0.031) and autumn (H' = 2.365 +/- 0.032) (P <0.05). While for spatial variations, the richness of Microcystis at River Mouth (H' = 2.015 +/- 0.074) was higher than at other sites during four seasons (P < 0.01). Very few differences of Microcystis diversity in the same season were observed among the other three sites (P > 0.05). Canonical correspondence analysis (CCA) was performed to elucidate the relationships between Microcystis operational taxonomic units (OTUs) composition and the environmental factors. Results of CCA revealed that temperature was strongly positively correlated with the first axis (r = 0.963), while TSS was negative correlated with the second axis (r = -0.716). Phylogenetic tree based on the sequencing results of target bands on DGGE gel indicated that samples collected in summer and winter constituted two separated clusters.

[Mixture effects to vitellogenin induction by four environmental estrogens in freshwater fish].

Combined effects of estrogenic compounds to high risk life-form were demonstrated, and the study method on combined effects of environmental contaminant mixture and environmental risk assessment were also discussed. A nonlinear aggression was determined on the changes of plasma vitellogenin concentration in crucian carp via the environmental pollutant exposure concentration, and the concentration-response relationship was determined for the single chemical of estradiol, ethynylestradiol, bisphenol A, and octylphenol, and that of the mixed compounds at equipotent concentrations. The combined effects of the four xenoestrogens were tested using indices of mixture toxicity and the biomathematical models of concentration addition or independent action. Weibull function was indicated as the best-fit function (R2 > or = 0.92) with curve estimation, the 95% confidence limits of effect concentration was achieved using the bootstrap method, the media effective concentration (EC50) with 95% confidence interval was 0.007 9 (0.006 8-0.010 0), 0.098 7 (0.090 0-0.111 0), 63.50 (56.58-70.62) and 250.59 (228.46-271.99) Mg x L(-1) respectively. Results suggested that estrogenic chemicals acted together in an additive manner and the combined effects can be accurately predicted in whole range of exposure concentration by the concept of similar joint action or concentration addition.It is proved as a scientific and feasible method to apply the model of joint action whereas the outcome of indices with a great deal of indetermination.

[Comparison of overwintering and rrecruitment of cyanobacteria in Taihu Lake and Chaohn Lake].

Dynamics of overwintering and recruitment of cyanobacteria were studied in Taihu Lake and Chaohu Lake. The results demonstrated that cyanobacteria sank to the sediment in autumn (November) and recruited to water column in May in Taihu Lake. From November to next May, the cyanobacteria kept growing with an increased growth rate from March to May in the sediment. A similar pattern of overwintering and recruitment of cyanobacteria was found in Chaohu Lake, which showed the cyanobacteria sinking in November and recruitment in spring with the cyanobacteria growing in the sediment, while the cyanobacteria recruited to water column from March to April. Our results showed there was typical overwintering and recruitment of cyanobacteria in Taihu Lake and Chaohu Lake. The numbers of cyanobacteria in sediment represented by the almost same pigments content in different lake areas of Taihu Lake according to nutrient levels probably implied the little relationships of the numbers in sediments with the summer bloomed biomass of cyanobacteria.

Negative phototropism of rice root and its influencing factors.

Some characteristics of the rice (Oryza sativa L.) root were found in the experiment of unilaterally irradiating the roots which were planted in water: (i) All the seminal roots, adventitious roots and their branched roots bent away from light, and their curvatures ranged from 25 degrees to 60 degrees . The curvature of adventitious root of the higher node was often larger than that of the lower node, and even larger than that of the seminal root, (ii) The negative phototropic bending of the rice root was mainly due to the larger growth increment of root-tip cells of the irradiated side compared with that of the shaded side, (iii) Root cap was the site of light perception. If root cap was shaded while the root was irradiated the root showed no negative phototropism, and the root lost the characteristic of negative phototropism when root cap was divested. Rice root could resume the characteristic of negative phototropism when the new root cap grew up, if the original cells of root cap were well protected while root cap was divested, (iv) The growth increment and curvature of rice root were both influenced by light intensity. Within the range of 0-100 mumol . m(2) -s(-1), the increasing of light intensity resulted in the decreasing of the growth increment and the increasing of the curvature of rice root, (v) The growth increment and the curvature reached the maximum at 30 degrees C with the temperature treatment of 10-40 degrees C. (vi) Blue-violet light could prominently induce the negative phototropism of rice root, while red light had no such effect. (vii) The auxin (IAA) in the solution, as a very prominent influencing factor, inhibited the growth, the negative phototropism and the gravitropism of rice root when the concentration of IAA increased. The response of negative phototropism of rice root disappeared when the concentration of IAA was above 10 mg . L(-1).