Influence of water content on mechanical behaviour of gastropod taenioglossan radulae

One molluscan autapomorphy is the radula, the organ used for feeding. Here, for the first time, the performance and failure of taenioglossan radular teeth were tested in a biomechanical experiment which in turn allowed building hypotheses about tooth functionalities. Shear load was applied to tooth cusps with a force transducer until structural failure occurred, the broken area was measured, and finally breaking stress was calculated. These experiments were carried out under dry and wet conditions. Our results show that certain tooth types can resist higher stresses and are rather specialised to loosen food items from a surface, whereas other teeth can only gather food particles. The experiments additionally illustrate the high influence of the water content on the resulting breaking stress. When wet teeth were tested, their ductility and ability to avoid being fractured by an obstacle increased. Their flexibility also allowed them support from teeth of adjacent tooth rows, which made the whole system less prone to failure. Our results were compared with the previous data on the mechanical properties and feeding simulations. This study provides a keystone for further comparative studies aiming at connecting diversity of radulae with their possible adaptations to the ingesta.

A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study

This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF) and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF) and pelvic brim long screws fixation (PBSF) provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF), L-shaped plate fixation (LPF), and H-shaped plate fixation (HPF); AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head.

The Changes of the Corneal Tissue Structures and Biomechanical Properties in the Process of Cornea Post-Embryonic Development

To investigate the changes of corneal tissues morphological structure and biomechanical properties in different month age rabbits, the eyeballs of the 1 month, 2 month and 3 month-old-New Zealand white rabbits were obtained and getting the cornea tissues, and then measured the thickness of the cornea tissues. The first part of the corneal tissue was used to observe cornea structure with HE staining. The second part was used to observe collagen fibrils by electron microscope. The third part of the cornea tissues were cut into strips and used to test the elastic modulus of the cornea on Instron5544 tester. The thickness of the cornea was increased with month age. HE staining observation shows that the numbers of corneal fibroblasts were decreased and the fiber bundle increased with month age. Electron microscope observation shows that the diameters of collagen fibrils were increased at 2 and 3 month. Biomechanical experiment results reveal that cornea tissues elastic modulus was increased with month age. In the post-embryonic stages, the structure of cornea, the structure and number of collagen fiber, the number of corneal fibroblasts and the biomechanical properties of cornea were changed continually.

Biomechanical Research on Operations of Hangmann Fracture with Finite Element Method

There are increasing incidence of Hangman fracture with the development of society and industrialization. The research on upper cervical spine concerning hangman fracture is able to be well carried on with The finite element method(FEM) developing. The research includes a biomechanical experiment of cadaver specimens and FEM analysis accordingly. The finite element models of geometrical complex structure from medical images are generated automatically, the research presents simulation of different surgical option of hangman fracture, testified the models by loads, calculated the stabilities and stress of models. The corresponding results were summarized with experiment of cadaver specimens. The research demonstrate that clinical therapeutics is an good option for Hangman fracture with C2-3 inter-vertebral disc injury.