Recyclable collagen is a potential candidate to be used as development prototypes in biomaterial scientific research.

In recent years, the increase in the generation of waste (e.g., bones and skin) from the processing of fish-based food related to the increase in fish consumption and the accumulation of synthetic polymers in the environment are causing major environmental concerns. Hydroxyapatite (HA) extracted from the bones and collagen from the skin of fish processing residues can be combined with synthetic polymers to maximize the use of waste material derived from fish while simultaneously reducing the use of synthetic polymers. Hence, in this study, collagen and HA were extracted from the carcasses of Lophiosilurus alexandri, and the obtained materials were reused to prepare low-density polyethylene (LDPE) blends and composites. The integrity of the triple helix structure of collagen was confirmed by FTIR and DSC showing that there was no collagen denaturation during its extraction and sample processing. The results indicated that the material produced by the incorporation of collagen into LDPE compatibilized with polyethylene-graft-maleic anhydride exhibits good mechanical and surface properties for use as a support material for ornamental articles, among other applications.

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This study tested an external tag for juveniles of Lophiosilurus alexandri and measured the effects of tagging in different size classes of fishes. Experiment 1 evaluated the retention rate and influence of the tag on survival and growth of three hundred fishes divided Small, Medium and Large size classes. After 90 days of experiment the fishes had 100% survival and the tag had a higher retention rate for animals of the Large size class. Experiment 2 evaluated the tag’s influence on hematology parameters of forty-two fishes at 5, 10 and 30 days post-tagging. In this experiment both tagged and untagged animals experienced 9.4% mortality. The hematocrit was higher on the 30th day for tagged animals than for untagged animals. No difference was observed for leukocytes, plasma protein, erythrocytes and mean corpuscular volume. It was concluded from Experiment 1 that the tag reduced growth performance when applied to small sized juvenile L. alexandri, and that the tag retention rate increased with increasing animal size. Among the hematological parameters studied for juveniles on the Experiment 2 the tag only influenced the hematocrit parameters, which shows that the tag can be used without considerable influence on the hematological parameters of juvenile L. alexandri.

This paper is a study of the role of functionalized multi-walled carbon nanotubes (MWCNT-COOH) and single-walled carbon nanotubes (SWCNT) in improving the mechanical properties of epoxy resins. In nanotube-based polymeric composite it is anticipated that high elastic modulus can be achieved by taking advantage of the interfacial friction between the nanotubes and the polymer. In order to evaluate the CNT effect on polymer composites, different weight fractions of CNTs and two different kinds of CNTs were dispersed in the matrix. First, the damping characteristics of the samples with 0, 0.5, 1 and 1.5 wt.% nanotube contents were measured and then the tensile modulus was determined experimentally. The experiments showed an increase of the elastic modulus and the damping due to adding CNTs. Theoretical models were used to show the effect of added reinforcement to compare with experimental elastic modulus data. The results showed that a modified Rule of Mixtures model, incorporating the effect of fibre orientation in 3D was closest to the experimental results.