Tissue Response to Porous Materials used for Ossicular Replacement Prostheses

1984 ◽  
pp. 29-40 ◽  
Author(s):  
M. Spector ◽  
J. F. Teichgraeber ◽  
J. H. Per-lee ◽  
R. T. Jackson
Cryogenics ◽  
1980 ◽  
Vol 20 (10) ◽  
pp. 587-591 ◽  
Author(s):  
H. Appel ◽  
F.X. Eder

2017 ◽  
Vol 890 ◽  
pp. 308-311
Author(s):  
Jakub Skibinski ◽  
Tomasz Wejrzanowski ◽  
Krzysztof Jan Kurzydlowski

In the present study modeling of permeability of open-porosity ceramic materials used in non-polarizing electrodes is addressed. The structure of the material filling the electrode determines the infiltration of the ceramic structure by electrolyte, which influences the efficiency of the electrodes. The composition of electrode material was characterized with Scanning Electron Microscope Hitachi S3500N with EDS detector and the structure was determined with use of XRadia XCT400 tomograph . The complex geometry of porous materials has been designed using procedure based on Laguerre-Voronoi tessellations (LVT). A set of porous structures with different geometrical features has been developed using LVT algorithm. The approach used here allows to investigate the influence of geometrical features such pore size variation on the permeability of studied materials. Pressure drop characteristics of the developed structures has been analyzed using finite volume method (FVM). The results show that permeability of porous materials is strongly related with distribution of pore size. The study exhibits the utility of developed design procedure for optimization of non-polarizing electrodes performance.


2012 ◽  
Vol 529-530 ◽  
pp. 331-336
Author(s):  
Kalan Bastos Violin ◽  
Christiane Ribeiro ◽  
Tamiye Simone Goia ◽  
José Carlos Bressiani ◽  
Ana Helena de Almeida Bressiani

Many techniques are used to assess biomaterials implants, always intending to measure osseointegration success and tissue response facing the implanted material. Calcium phosphates are widely used as biomaterial and a major component of bone. Many processing methods have been used to achieve porous materials to allow bone ingrowth with an osteoconductive scaffold for bone. To obtain the macroporous BCP implant it was processed by direct consolidation using the protein-action technique, a globular protein based consolidation with ovalbumin. The samples were sintered at 1250°C for 30 minutes, after sintering samples were cut in 4mm diameter cylinders, with 73% volume of porosity and mean pore size ranging about 100 µm. In the present work the macroporous BCP of HAp:β-TCP is assessed after bone implantation in rabbits tibia by lectinhistochemistry (LHC) technique. Lectins are proteins from non-imune origin which binds with strong specificity carbohydrates, LHC is a technique which mark histologically carbohydrates present in glycoproteins of cells. The macroporous BCP cylindrical samples were implanted in male rabbits tibia to the evaluation of biocompatibility and osseointegration in a period of 2 weeks to 4 weeks. After euthanasia of rabbits, tibia samples from the surgery site were taken and fixed with formalin, decalcified, dehydrated and embedded with paraffin to perform histological slides for both morphological and molecular evaluation. The morphological evaluation were performed on histological slides stained with Haematoxilin and Eosin (HE), while for molecular evaluation LHC was performed on histological slides using the lectins PNA, UEA-1, WGA, sWGA and RCA-1 (Vector Labs). All samples osseointegrated well with the bone and the neoformed bone surrounding the implant took the shape of its surface. The implants also allowed bone ingrowth inside the pores towards the center of implant, characterized by islets of round bone present in the HE stained slides.


2019 ◽  
Vol 27 (1) ◽  
pp. 3-20 ◽  
Author(s):  
L Yuvaraj ◽  
S Jeyanthi

This study investigates the acoustic performance of a countersunk micro-perforated panel, along with two distinct porous materials used in a multilayer porous absorber configuration. Additive manufacturing is applied to create sub-millimeter perforation with different hole spacings on polymer micro-perforated panels. Experiments are conducted in an impedance tube, in which the effects of the perforation ratio, air gap, and varying porous layer configurations on the sound absorption capabilities are investigated. For validation, considering the converging hole profile in the micro-perforated panel, an integration method with end correction is used to calculate the tapered section impedance, and the traditional Maa theory is used for the uniform hole. The theoretical impedance of the multilayer absorber is calculated using the transfer matrix method and subsequently compared to the experimental results. The results demonstrate that the countersunk hole micro-perforated panel exhibits a significant improvement in sound absorption, and the introduction of porous materials extends the sound absorption bandwidth. Furthermore, the results indicate that the sound absorption capability depends on the porous material placement in the multilayer absorber configuration.


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