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The pollution of sediments around Lu Ban Island is a serious environmental issue that is threatening human health. The concentration of As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn at 73 layer points were investigated, vertical distribution characteristics, correlation among potential toxic elements and potential ecological risks of sediments at different depth were analyzed. The following results were obtained, (1) the hypothesis that there was a linear relationship between concentration of potential toxic elements and the reciprocal of deep was reasonable. Based on hypothesis, the ultimate value of concentration by making depth go to infinity was regarded as the background concentration. The background concentration of As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn are respectively 4.94 mg/kg, 0.20 mg/kg, 15.48 mg/kg, 58.41 mg/kg, 0.062 mg/kg, 26.96 mg/kg, 20.29 mg/kg, and 53.31 mg/kg. (2) But correlation between Ni and As was relatively weak, high degree of correlation among other potential toxic elements were found. Based on their correlation, eight potential toxic elements were classified into three groups. First group included Ni and Cr, mainly releasing by coal burning; Cu, Pb, Zn, Hg, and Cd were grouped together, possibly due to their shared source of fish cage culture; Arsenic with relatively weak correlation with other potential toxic elements was classified as a separate class, which was usually one important mineral resource associated with phosphate. (3) Potential ecological risk index (PERI) of sediment above − 0.40 m belonged to moderate risk, the PERI of sediment in − 0.10 m, − 0.20 m, and − 0.40 m were 289.06, 254.33, and 201.44, respectively. Sediment below − 0.40 m belonged to low risk with average PERI value 112.82, with no significant changes in PERI values. The order of contribution to PERI was Hg > Cd > As > Cu > Pb > Ni > Cr > Zn. (4) According to result of cluster analysis and potential ecological risk, the potential ecological risk of sediment above − 0.40 m mainly contributed by potential toxic elements of Cu, Cd, Hg, Pb, and Zn sharing source of fish cage culture. [Display omitted] • The hypothesis the linear relationship between concentration and reciprocal of depths is proposed. • Distribution rule of potential ecological risk of sediments in different depths is investigated. • Identify the potential heavy metals pollution resource in high-density cage culture reservoir. [ABSTRACT FROM AUTHOR]

Haemophilus parasuis is the etiological agent of Glässer's disease, which is characterised by fibrinous polyserositis, meningitis and polyarthritis, causing severe economic losses to the swine industry. In this study, a loop-mediated isothermal amplifification (LAMP) test was developed to improve the specifificity, facility and speed of diagnosis of H. parasuis isolates. The LAMP assay rapidly amplifified the target gene within 50 min incubation at 63 °C in a laboratory water bath. The LAMP amplicon could be visualised directly in the reaction tubes following the addition of SYBR Green I dye. The detection limit of this LAMP method was 10 CFU/mL, which was 10 times more sensitive than the earlier 16S rRNA polymerase chain reaction (PCR) test conducted by Oliveira, Galina and Pijoan (2001), and no cross-reactivity was observed from other non-H. parasuis strains. This LAMP test was evaluated further on 187 clinical specimens from pigs suspected of being infected with H. parasuis. Forty-three were found positive by bacterial isolation of H. parasuis, as well as by the 16S rRNA PCR and LAMP tests. The 43 H. parasuis isolates were classifified into 9 serovars and had 37 genetic patterns when analysed by pulsed-field gel electrophoresis (PFGE). This displayed that various H. parasuis serovars and genotypes were widely distributed in South China. Therefore, the speed, specifificity and sensitivity of the LAMP test, the lack of a need for expensive equipment, and the visual readout showed great potential for a correct clinical diagnosis of H. parasuis in favour of controlling Glässer's disease. [ABSTRACT FROM AUTHOR]

The X-ray method is used extensively to determine the residual stress in bulk or thin film materials on the assumptions that the material is composed of fine crystals with random orientation and the stress state is biaxial and homogeneous through the X-ray penetrating region. But the method cannot be used in textured films due to oscillations in ε-sin² ψ relation. In this paper, a new method is proposed for measuring residual stress in cubic films with any [hkl] fiber texture. [ABSTRACT FROM AUTHOR]

Constant loading rate divided by load (P/P) indentation tests have been conducted on high purity copper at room temperature. The results show that: 1) The loading curves can be fitted to a power-law relationship of the form P = Chn and the exponent n increases with decreasing P/P. 2) The hardness value itself, and its decreasing rate with depth, increase with increasing P/P. 3) A constant P/P can result in a constant indentation strain rate (h/h), even if indentation size effects (ISE) exist in the materials. 4) The relationship between P/P and h/h can be shown to be P/P = n ⋅ (h/h). [ABSTRACT FROM AUTHOR]