Functional interface micromechanics of 11 en-bloc retrieved cemented femoral hip replacements

Contains fulltext : 88556.pdf (publisher's version ) (Open Access)BACKGROUND AND PURPOSE: Despite the longstanding use of micromotion as a measure of implant stability, direct measurement of the micromechanics of implant/bone interfaces from en bloc human retrievals has not been performed. The purpose of this study was to determine the stem-cement and cement-bone micromechanics of functionally loaded, en-bloc retrieved, cemented femoral hip components. METHODS: 11 fresh frozen proximal femurs with cemented implants were retrieved at autopsy. Specimens were sectioned transversely into 10-mm slabs and fixed to a loading device where functional torsional loads were applied to the stem. A digital image correlation technique was used to document micromotions at stem-cement and cement-bone interfaces during loading. RESULTS: There was a wide range of responses with stem-cement micromotions ranging from 0.0006 mm to 0.83 mm (mean 0.17 mm, SD 0.29) and cement-bone micromotions ranging from 0.0022 mm to 0.73 mm (mean 0.092 mm, SD 0.22). There was a strong (linear-log) inverse correlation between apposition fraction and micromotion at the stem-cement interface (r(2) = 0.71, p < 0.001). There was a strong inverse log-log correlation between apposition fraction at the cement-bone interface and micromotion (r(2) = 0.85, p < 0.001). Components that were radiographically well-fixed had a relatively narrow range of micromotions at the stem-cement (0.0006-0.057 mm) and cement-bone (0.0022-0.029 mm) interfaces. INTERPRETATION: Minimizing gaps at the stem-cement interface and encouraging bony apposition at the cement-bone interface would be clinically desirable. The cement-bone interface does not act as a bonded interface in actual use, even in radiographically well-fixed components. Rather, the interface is quite compliant, with sliding and opening motions between the cement and bone surfaces.1 juni 201

Evaluation of functional dynamics during osseointegration and regeneration associated with oral implants

The aim of this paper is to review current investigations on functional assessments of osseointegration and assess correlations to the peri-implant structure.The literature was electronically searched for studies of promoting dental implant osseointegration, functional assessments of implant stability, and finite element (FE) analyses in the field of implant dentistry, and any references regarding biological events during osseointegration were also cited as background information.Osseointegration involves a cascade of protein and cell apposition, vascular invasion, de novo bone formation and maturation to achieve the primary and secondary dental implant stability. This process may be accelerated by alteration of the implant surface roughness, developing a biomimetric interface, or local delivery of growth-promoting factors. The current available pre-clinical and clinical biomechanical assessments demonstrated a variety of correlations to the peri-implant structural parameters, and functionally integrated peri-implant structure through FE optimization can offer strong correlation to the interfacial biomechanics.The progression of osseointegration may be accelerated by alteration of the implant interface as well as growth factor applications, and functional integration of peri-implant structure may be feasible to predict the implant function during osseointegration. More research in this field is still needed. To cite this article: Chang P-C, Lang NP, Giannobile WV. Evaluation of functional dynamics during osseointegration and regeneration associated with oral implants. Clin. Oral Impl. Res . 21 , 2010; 1–12.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78668/1/j.1600-0501.2009.01826.x.pd

Simulation of bone ingrowth

Abstract not availableMechanical Maritime and Materials Engineerin

DIGITAL IMPERATIVES FOR THE DEVELOPMENT OF THE FINANCIAL MARKET OF THE NATIONAL AND WORLD VECTOR

Аbstract. Trends in the modern financial market are characterized by new challenges of the financial environment and the impact of digital transformation, which form abnormal areas of development. Defining trends, digital models, determinants and technologies of the financial market has become an urgent necessity. The object of the study is the trends in the Ukrainian financial market and global markets of financial derivatives, Forex, ОТС markets group under digital transformation. For this purpose, we have applied the methods of nonlinear dynamics, time series, technical and fundamental analysis, modeling, forecasting, market divergence, fluctuations and behaviorism. The study of the financial market has identified: the dominant trend in digital imperatives and digital technologies of the financial space; the cyclic and behavioristic development of the Ukrainian financial market; the growth in actualization of activities of Ukrainian financial institutions, which is associated with the alternative parabanking services; higher growth rates (3,3 units) of exchange transactions with precious metals, the dependence of the dynamics of currency on the impact of the global digital imperatives; the growth in OTC derivatives trades (the rate of growth of 1.1 units). Determinants of trends financial market are: financial and economic policy, digitalization of society, force majeure. The study of forecast patterns of changes in trends has enabled to determine the economic and mathematical model for calculating the index of forecasting the price of a digital financial asset and income from a transaction with cryptocurrency. A close correlation-regressive relationship (linear R2 = 0.6361, exponential R2 = 0.6948, power R2 = 0.7142) of the cryptocurrency exchange rate from the trading interest is determined (the elasticity coefficient is 2.7 units). Keywords: financial indicators, determinants, financial assets, derivatives, patterns, digital financial technologies, forecasting, Forex, OTC. JEL Classification G12, G13, G17 Formulas: 3; fig.: 7; tabl.: 3; bibl.: 16.</jats:p