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.
Age Factors ; Elasticity ; Female ; Friction ; Humans ; Male ; Sex Factors ; Skin ; Skin Physiological Phenomena

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.
Animals ; Collagen ; Durapatite ; Hemoglobins ; Hemolysis ; Humans ; Materials Testing ; methods ; Methemoglobin ; analogs & derivatives ; Rabbits

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.
Amputees ; Animals ; Elasticity ; Female ; Friction ; Implants, Experimental ; Male ; Models, Biological ; Rabbits ; Random Allocation ; Skin ; Skin Physiological Phenomena

MRI simulator(MRI-Sim) images have unique clinical advantages with higher resolution of soft tissue and clearer visualization of tissue boundaries. Thus, the precise positioning of the tumor target area can be achieved and it is widely used in the field of radiotherapy. This article focuses on the acceptance test project and image quality assurance work of MRI-Sim equipment. The obtained ACR phantom images were used to analyze various image quality assurance indicators, and the results all reached the set standards, thereby ensuring that the obtained images meet the requirements of clinical applications.
Magnetic Resonance Imaging ; Phantoms, Imaging ; Quality Assurance, Health Care

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.
Biocompatible Materials ; Bone Cements ; Calcium Phosphates ; Materials Testing ; Polymers

The segmentation of organs at risk is an important part of radiotherapy. The current method of manual segmentation depends on the knowledge and experience of physicians, which is very time-consuming and difficult to ensure the accuracy, consistency and repeatability. Therefore, a deep convolutional neural network (DCNN) is proposed for the automatic and accurate segmentation of head and neck organs at risk. The data of 496 patients with nasopharyngeal carcinoma were reviewed. Among them, 376 cases were randomly selected for training set, 60 cases for validation set and 60 cases for test set. Using the three-dimensional (3D) U-NET DCNN, combined with two loss functions of Dice Loss and Generalized Dice Loss, the automatic segmentation neural network model for the head and neck organs at risk was trained. The evaluation parameters are Dice similarity coefficient and Jaccard distance. The average Dice Similarity coefficient of the 19 organs at risk was 0.91, and the Jaccard distance was 0.15. The results demonstrate that 3D U-NET DCNN combined with Dice Loss function can be better applied to automatic segmentation of head and neck organs at risk.