Mechanical Properties and Biocompatibility of a Biomaterial on the Basis of Natural Hydroxyapatite and an Endodentic Cement1

Mechanics of Composite Materials - The biocompatibility of hydroxyapatite is appropriate for bone substitution, but its mechanical properties have to be improved. In this work, a natural...     

A method for finding smoothly varying rules in Multidimensional time series

An approach to discovering rules in nonstationary k-valued Multidimensional time series is proposed. It allows one to discover rules that are subject to “smooth” structural changes with the course of time. A measure of rule similarity is proposed to describe such changes, and its application in the form of weight in the graph of rules is discussed. The discovered rules can be used to predict the next elements in the multidimensional time series, to analyze the phenomenon described by this multidimensional time series, and to model it. This allows one to use the proposed algorithm for predicting time series and for examining and describing the processes that can be represented by a multidimensional time series. Means for the direct practical application of the proposed methods of the analysis and prediction of time series are described, and the use of those methods for the short-range prediction of a real-life multidimensional time series consisting of the stock prices of companies operating in similar fields is discussed.     

Technology and Some Mechanical Properties of Biocomposites Based on Mineral Components

Two types of new composite implant materials are investigated. Their mechanical characteristics, biocompatibility, and the dynamics of bond strength between the biocomposites and a live bone tissue are determined. The first type of the biomaterials is based on silicate glass and hydroxyapatite. Both the natural and a synthetic hydroxyapatite were used. The second type of the biomaterials was made of an ultrahigh-molecular polyethylene and the synthetic hydroxyapatite. Composite materials of both the types were implanted in the rabbit femur. The bond strength between the bone tissue and the implants was determined in 2, 4, 10, and 25 weeks.__________Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 2, pp. 273–282, March–April, 2005.