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The liquid solidification paths of ternary eutectic and quasiperitectic Al-Cu-Mg alloys in Al-rich corner were calculated using an extended microsegregation model. The user's programs were coupled with CALPHAD software for calculating the thermodynamic data of the investigated alloys. The influences of initial composition, average solidification rate, assumption of dendrite morphology, diffusion coefficient and the united solid back diffusion (SBD) parameter Фn on solidification paths were investigated. It was found that differences of the above parameters could greatly affect the liquid solidification path, types and quantities of the precipitated phases, and concentration of solutes in liquid phase. Solidification experiments were carried out with four Al-Cu-Mg alloys to verify the accuracy of the calculation, and reasonable agreements were obtained between the predicted solidification paths and the experiment results. [ABSTRACT FROM AUTHOR]

The solidification paths of ternary eutectic Al-Si-Mg alloys in the Al-rich corner were investigated by numerical calculation. The thermodynamic data needed in the calculation were obtained by direct coupling simulation program with a CALPHAD software Thermo-Calc via its TQ6-interface and COST2 database. The influences of the initial compositions, dendrite morphologies and the solid diffusion coefficients on the solidification path were analyzed. The solidification paths were calculated with assumed different solid diffusion coefficients varying in eight orders of magnitude and different dendrite morphologies including the five basic geometrical shapes of spherical, cylindrical, plate-like, inward cylindrical, inward spherical and the assumed equiaxed dendrites. The calculated results comparisons showed that initial compositions, dendrite morphologies and solid-back diffusion can significantly influence the solidification path and the type and amounts of eutectic of Al-Si-Mg alloys. The predicted solidification paths and the eutectic fraction of selected Al-Si-Mg alloys calculated with assumption of equiaxed dendrite morphology agreed well with the experimental results. [ABSTRACT FROM AUTHOR]

DNA vaccines expressing Haemonchus contortus H11 antigen with or without interleukin (IL)-2 were tested for protection against H. contortus infection in goats. Sixteen goats (8-10 months of age) were allocated into four trial groups. On days 0 and 14, group 1 was immunised with a DNA vaccine expressing H11 and IL-2 and group 2 was immunised with a DNA vaccine expressing H11 only. Group 3 was an unvaccinated positive control group challenged with H. contortus third stage larvae (L3). Group 4 was an unvaccinated negative control group that was not challenged with L3. Animals in groups 1-3 were challenged with 5000 infective H.contortus L3 14 days after the second immunisation. Transcription of H11 and IL-2 was demonstrated in muscle by reverse transcriptase-PCR 10 days after primary immunisation and translation of H11 was detected by Western blot analysis 7 days after the second immunisation. Following immunisation with a DNA vaccine expressing H11 and IL-2, high levels of specific serum immunoglobulin (Ig) G, non-specific serum IgA. mucosal IgA, CD4+ T lymphocytes, CD8+ T lymphocytes and B lymphocytes were produced. Following challenge with L3, cumulative mean faecal worm egg counts and worm burdens in group 1 were reduced by 56.6g and 46.7%, respectively, while corresponding reductions in group 2 were 44.8g and 38.0%. There was a small but significant difference in abomasal worm burdens in goats in groups 1 (395.3 ± 37.6) and 2 (459.5 ± 101.6) compared to group 3 (741.5 ±241.5; P < 0.05). Use of a DNA vaccine expressing H11 and IL-2 conferred partial protection against Haemonchus contortus infection in goats. [ABSTRACT FROM AUTHOR]