Notice of RetractionRelationship between thickness of siliconized layer prepared by electrodeposition and components of molten salts
The siliconized layer on low silicon steel sheet was obtained by electrodeposition in KCl-NaCl-NaF-SiO2 molten salts. Proportion of molten salts was designed using symmetry-simplex method. A regression equation was found to be a better fit for the relationship between thickness of the siliconized layer and salts components. Based on the equation, the thickness isoline was plotted to reveal the influence of salts proportion on thickness. The results showed that NaF content had a significant effect on the thickness of the siliconized layer. The thickness increased gradually with the increase of NaF content. When NaF was 0.4-0.6 mole fraction, the thickness increased remarkably. Furthermore, when the concentration of KCl was kept constant, the ratio of NaF/NaCl was important to control the thickness. The thickness was relatively small as mole fraction ratio NaF/NaCl was about 2:3.
Optimum designs for optimum mixtures
In a mixture experiment, the measured response is assumed to depend only on the relative proportion of ingredients or components present in the mixture. Scheffe [1958. Experiments with mixtures. J. Roy. Statist. Soc. B 20, 344-360; 1963. Simplex--centroid design for experiments with mixtures. J. Roy. Statist. Soc. B 25, 235-263] first systematically considered this problem and introduced different models and designs suitable in such situations. Optimum designs for the estimation of parameters of different mixture models are available in the literature. However, in a mixture experiment, often one is more interested in the optimum proportion of ingredients. In this paper, we try to find optimum designs for the estimation of optimum mixture combination on the assumption that the response function is quadratic concave over the simplex region.
Scaffolds Containing Spirulina sp. LEB 18 Biomass: Development, Characterization and Evaluation of In Vitro Biodegradation.
Polymer nanofibers are nanomaterials that can be used as scaffolds in tissue engineering. The objective of this study was to develop, characterize and evaluate the in vitro degradation of a biomaterial consisting of nanofibers produced from biodegradable and biocompatible polymers with potential applications as a scaffold for tissue regeneration and containing Spirulina sp. LEB 18 biomass as the bioactive compound. The polymers used were poly(hydroxybutyrate-co-hydroxyvalerate) and polycaprolactone. The polymeric solutions exhibited sufficiently high viscosity to produce uniform nanofibers with diameters between 335 and 617 nm. The applied conditions were as follows: a voltage of 25 kV, a distance from the capillary to the collector of 120 mm, a capillary diameter of 0.80 mm, and 12% polycaprolactone and a blend of 5% polycaprolactone and 10% poly(hydroxybutyrate-co-hydroxyvalerate). The biomass was incorporated into the nanofibers at a concentration of 3%, and the incorporation was confirmed using confocal microscopy. The nanofibers were characterized using differential scanning calorimetry and thermogravimetric analysis, which showed that the addition of biomass did not alter the thermal properties of the biomaterial. The addition of biomass improved the tensile strength and elongation of the scaffolds compared with those produced with polymers alone. A biodegradation assay showed enzymatic action toward the biomaterial, simulating the behavior of natural tissue. Based on the analysis, it was concluded that the scaffolds that were produced have the potential to be applied in the field of tissue regeneration as biomaterials with pharmacological properties.