Mechanical Reinforcement Strategy of Calcium Phosphate Cements by Loading Polymers / 中国医疗器械杂志

Calcium phosphate cement (CPC) is well known for the excellent bioactivity and biocompatibility, however, CPC has been used only for the repair of non-load bearing bone defects due to its brittle nature and low flexural strength. Polymer reinforced CPC has been considered as one of the most effective strategies for mechanical reinforcement. This paper summarizes various kinds of polymers loaded CPC:fiber reinforcement, microsphere reinforcement and dual setting cements. It is aimed to analyze the advantages, disadvantages and principles of the polymers reinforced CPC, and so as to lay a foundation for the further research of improving and manufacturing the CPC with ideal mechanical properties.

Effects of frictional properties on traumas of rabbit skin / 生物医学工程学杂志

Simulative experiments on skin traumas between prosthetic socket materials and residual limb skin were investigated by using the means of tribology, histology and animal experiment. Healthy adult rabbits were used as animal model and their denuded back skin was selected as experimental position to simulate residual limb skin. The effects of different normal load and reciprocal sliding frequency on rabbit skin trauma grade were investigated by using a reciprocal sliding skin friction testing apparatus to simulate prosthesis gait. The traumatic subcutaneous tissue slice was stained with hematoxylineosin and the morphology was observed under the optical microscope. The scab thickness of traumatic skin was measured under x 10 object lens. The inflammatory cells were counted in a given visual field under x 20 object lens. The statistical significance analysis of scab thickness and inflammatory cells were carried out to assess the effect of different frictional conditions on skin pathological traumas. The results showed: the greater normal load and higher reciprocal sliding frequency applied on the rabbit skin, the more serious injury to skin and more inflammatory cells in the subcutaneous tissue at the same time. The findings provide a theoretical basis of comfortized prosthesis design and gait analysis for the amputee.

Frictional properties of human skin at different ages, gender and anatomical regions / 生物医学工程学杂志

A reciprocal sliding skin friction testing apparatus was performed to investigate human skin frictional properties of different physiological factors such as different ages, gender and anatomical regions. Student's t-test for non-paired data and one-way analysis of variance (ANOVA) were used in data analysis. Fisher LSD was used for multiple comparison on the statistical significance of the coefficients. The results showed that the skin frictional properties at the different anatomical regions were strongly dependent on the age. The differences of friction coefficients at the different anatomical regions became negligible with the increase of age. The skin frictional properties of different gender at the same anatomical region and age exhibited no significant differences. The friction coefficients of different ages at the same anatomical regions showed significant differences.

Comparison between hemolysis percentage measurement and hemiglobincyanide measurement for standardizing the evaluation of hemolytic properties of biomaterials / 生物医学工程学杂志

In this study, two methods--the supernatant hemoglobin spectrophotometry, i.e. hemolysis percentage measurement(according to ISO/TR 7405) and the hemiglobincyanide measurement(according to ISO 10993-4)--were used to assay the hemolytic properties of hydroxyapatite(bioceramics) and collagen (polymer). The results showed that the conclusions drawn from using the two methods were basically consistent, and the latter was more sensitive, stable and comparable. However, some of the procedures in the hemiglobincyanide method were not defined in details. So based on our experiments we have offered some suggestions and improvements, which do not deviate from ISO and ASTM standards, for hiher practicability of usig it in standardizing the evaluation of the hemolytic properties of biomaterials. Hemiglobincyanide measurement is worthy of wider application.