In this study, the biocompatibility and in vitro degradation behaviour of a commercial zinc-based alloy (Zn-5 Al-4 Mg) were evaluated and compared with that of pure zinc for temporary orthopaedic implant applications. Biocompatibility tests were conducted using human alveolar lung epithelial cells (A549), which showed that the zinc alloy exhibits similar biocompatibility as compared to pure zinc. In vitro degradation evaluation was performed using weight loss and electrochemical methods in simulated body fluid (SBF) at 37 °C. Weight loss measurements revealed that the degradation of the zinc alloy was slightly lower during the initial immersion period (1–3 days), but marginally increased after 5 and 7 days immersion as compared to pure zinc. Potentiodynamic polarisation experiments showed that the zinc alloy exhibits higher degradation rate than pure zinc. However, electrochemical impedance spectroscopy analysis suggests that pure zinc is susceptible to localized degradation, whereas the zinc alloy exhibited passivation behaviour. Post-degradation analysis revealed localized degradation in both pure zinc and the zinc alloy.

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IObjective: To determine if rounding of the inferior rectus muscle on coronal computed tomographic (CT) scans predicts disruption of the periorbita in orbital floor fractures and therefore predicts delayed enophthalmos.Design: Cadaveric study with CT scan analysis. I Setting: Cadaveric laboratory and CT scanner at a tertiary care hospital in London, Ontario.Methods: Each orbit of each cadaveric head was randomly assigned to have either intact or disrupted periorbita. Progressively larger orbital floor fractures were made and CT scans were taken before fractures and after each fracture to assess the shape of the inferior rectus muscle. Measurements were made of the length of the long and short axis of the inferior rectus muscle using CT analysis software. The short to long axis ratio was then compared.Main Outcome Measures: Change in the short to long axis ratio of the inferior rectus muscle and correlation of the ratio with intact and disrupted periorbita.Results: Orbital floor fractures measuring 1 x 1 cm show an increase in the short to long axis ratio (rounding) of the inferior rectus muscle only if the periorbita is disrupted. Orbital floor fractures measuring 2 x 2 cm show rounding of the inferior rectus muscle regardless of whether the periorbita is intact or disrupted; however, the degree of rounding is greater if the periorbita is disrupted.Conclusions: For small orbital floor fractures, rounding of the inferior rectus muscle predicts periorbital disruption. This may therefore represent an indication for early surgical repair to prevent delayed enophthalmos. SOMMAIREObjectif: Determiner si un arrondissement du muscle droit inferieur a la tomodensitometrie predit une interruption de la periorbite dans une fracture du plancher orbitaire ce qui pourrait signer une enophtalmie retardee.Devis: Etude sur cadavres avec analyse des tomodensitometries. Localisation: Hopital de soins tertiaires a London, Ontario.Methodes: Chaque orbite de chaque tete a ete assigne au hasard entre le groupe avec periorbite intacte ou celul avec interruption. Nous avons cree des fractures de plus en plus grandes dans le plancher en prenant une tomodensitometrie avant et apres chaque fracture pour evaluer la forme du muscle droit inferieur. Nous avons mesure la longueur des axes longs et courts du muscle droit inferieur grace a un logiciel d'analyse. Nous avons ensuite compare les ratios des deux axes.Variable Evaluees: Changement dans le ratio des deux axes et correlation entre le ratio et I'etat de la periorbite. Resultats: Les fractures du plancher mesurant 1 x 1 cm montrent une augmentation du ratio (arrondissement du muscle droit inferieurl seulement quand la periorbite est interrompue. Par contre les fractures mesurant 2 • 2 cm montre toutes un arrondissement que la periorbite soit intacte ou non, mais le degre augmente quand la periorbite est interrompue.Conclusion: Pour les petites fractures du plancher orbitaire, un arrondissement du muscle droit inferieur predit une interruption de la periorbite. Cela peut representer une in...

To our knowledge, this is the first investigation to quantify the biomechanical properties of the facial retaining ligaments. Inherent ligament properties seem to be related to the changes observed in facial aging, although further study is required.