Biomedical subjects

F A Mahmud

Publications and source records attributed to F A Mahmud.

3 recordsLinked to original sources

PubMed1989

Non-contacting electrode system for the measurement of strain generated potentials in bone.

Current methods employing contact electrodes for the measurement of the electromechanical properties of bone produce errors in the measurement due to the effects of polarization at the bone-electrode interface, and the flow of electric charges in the bone measuring circuit. In addition, signal artefacts may result from the movement of an electrode in contact with a specimen undergoing mechanical deformation. The principles for a non-contacting method, based on charge induction on a conductive plate placed in the field of a charged body (bone), and the resulting non-contacting electrode system are presented in this paper. The new electrode enabled measurement of strain generated potentials (SGP) in bone with minimal effect from the measuring circuit and provided new results previously masked by contacting measurement methods. Furthermore, the new electrode is a potential tool for further investigation of the in vitro electromechanical behaviour of bone, particularly in partially hydrated specimens and in vivo, thereby avoiding invasive methods or use of ionizing radiation.

Action Potentials↗

PubMed1988

Model to characterize strain generated potentials in bone.

A model has been developed to characterize the strain generated potentials (SGPs) in bone. The model relates the SGP signal to the rotation (reorientation) of the spontaneous dipoles of bone in response to mechanical deformation. The effects of bone structural conditions and the measuring circuitry on the recorded potential are both accounted for by the model.

Animals↗

PubMed1988

Electrical effects in bone.

This paper presents a review of the work carried out on the electromechanical properties of bone over the past three decades. Research in this field has established the piezoelectric nature of bone and identified collagen as the generating source in dry bone. Some of the characteristics of the strain generated potential (SGP) signal from dry and hydrated bone were found to be unaccountable in terms of a classical piezoelectric theory. Modifications of the theory were suggested and in the case of fully hydrated bone, a new mechanism (streaming potential) has emerged. The paper also reports on recent developments in the field and presents results from microstructural (osteonic) studies and from fluid-filled bone. The review indicates the need for actual in vivo work because most of the reported data were obtained, in the last decade, from in vitro work and were considered valid in vivo. Modelling of the mechanism which produces the SGP has been considered to explain the characteristics of these potentials. A representative model recently developed by the present authors and co-workers is reported. This model relates the generated potential to reorientation of spontaneous dipoles and differentiates between the generated and recorded signal, thus identifying effects from the measuring circuitry. The clinical aspects of electricity of bone in assisting fracture healing and the different techniques employed are mentioned briefly. Emphasis on new techniques of piezoelectric implants and their future development is also reported.

Animals↗