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Biomedical subjects

A E Engin

Publications and source records attributed to A E Engin.

29 records · Page 2Linked to original sources
PubMed1983

Effects of oestrogen upon tensile properties of healing fractured avian bone.

The present work considers some of the effects of oestrogen treatment on the biomechanical properties of long bones during the process of osteosynthesis. The influence of the steroid was assessed by determining the tensile strength properties of treated and untreated healing fractured ossa radii. The ultimate tensile strength and modulus of elasticity were determined at one and two week post-fracture induction. In general, oestrogen treatment decelerated healing process of long bones. This was indicated by a significantly reduced ultimate tensile callus strength of oestrogen-treated birds over a two week period post-fracture induction. The same group also exhibited a significant increase in callus cross-sectional area while the elastic moduli of their bones were not significantly different at either one or two weeks post-fracture induction.

Animals↗
PubMed1983

Isometric muscle force response of the human lower limb.

This paper deals with isometric muscle force response of the human lower limb when the leg is subjected to various external forces applied on the knee and ankle joints. The major components of the research apparatus are a subject restraint system, a force application device which employs three sonic emitters, and an upper leg cuff with four sonic emitters. The sonic emitters are used to determine the direction and the location of the force application on the lower limb and the orientation of the upper leg with respect to the torso. The numerical results are presented from experiments conducted on three male and three female subjects to determine their isometric muscle resistance against external forces trying to dislodge their lower limbs from several initial configurations. Quantitative results on the isometric muscle force capability of the subjects, when their lower limbs are dislodged from the initial stowed position, are also presented. It is concluded that, although there are intra- and inter-subject variations for the maximum values of the resistive muscle forces of the lower limb, there are some trends in the behavior of their magnitudes. Incorporating the results of the present research into multi-segmented models of the human body should improve the long-time response capabilities of these models so that they can simulate more realistically the biodynamic events which take place when the human body is subjected to high magnitudes of external forces lasting more than a fraction of a second.

Adult↗
PubMed1981

Active muscle force and moment response of the human arm and shoulder.

This paper is concerned with collection of active muscle force and moment response data of the human arm and the shoulder complex when the arm is subjected to various external forces. The major components of the specially designed and built experimental apparatus for this research are a subject restraint system, a force application device which employs three sonic emitters, and an upper arm cuff with four sonic emitters. The sonic emitters are utilized to determine the direction and the location of the force application on the arm and the orientation of the upper arm with respect to the torso. The numerical results are presented from experiments conducted on three male and three female subjects to determine their active muscle resistance against the external forces to dislodge their arms from several initial configurations. Some representative results determining the active muscle force capability of the subjects when their arms are dislodged from the initial configuration are also presented. Incorporation of the results of the present research into the multi-segmented models of the human body should improve the long-time response of capabilities of these models. This type of response capability of the mathematical models is essential for the proper stimulation of the biodynamic events which take place prior to flail injuries.

Anthropometry↗
PubMed1980

Active muscle torques about long-bone axes of major human joints.

Incorporaton of the activee muscle torques into the multisegmented total-human-body models can be considered the next major improvement of These models. The first step toward achievement of this goal is to obtain active muscle torque data about long-bone axes of major human joints. This paper presents results of research conducted to collect such data at the shoulder, hip, elbow, knee, and ankle joints. Active muscle torques were determined about the long-bone axes of the upper arm, upper leg, lower arm, and lower leg, which are the body segments associated with the major joints mentioned. Numerical results are presented for three male subjects for a specific number of body segment orientations with respect to the joints. It was concluded that, although there are intra- and inter-subject variations for the maximum values of the acrive muscle torques about long-bone axes, there are some trends one can establish for the behavior of the magnitudes of these torques.

Ankle Joint↗
PubMed1979

Passive resistive torques about long bone axes of major human joints.

Multisegmented total-human-body models play an important role in studies such as vehicle crash victim simulation, pilot ejection and flailing. Proper biomechanical description of the major articulating joints of these mathematical models require passive resistive torque data for the rotational motions of the body segments about their long bone axes. This paper presents a research program which was developed to collect such data at the shoulder, hip, knee, elbow, and ankle joints. The research was conducted, with some obvious limitations, on live human subjects by means of specially designed experimental apparatus. The numerical results are presented for three subjects for the passive resistive torques about the long bone axes of the major articulating joints. It was concluded that the maximum tolerable passive resistive torques associated with the long bones of the lower extremities are more than twice the ones associated with the long bones of the upper extre mities.

Accidents, Aviation↗
PubMed1978

Application of a fluid-filled spherical sandwich shell as a biodynamic head injury model for primates.

In this paper, two areas are investigated: first, the effect of pulse duration on skull fracture and brain injury and, second, under what conditions a scaling can be considered between subhuman primates and human. The skull is modeled as a spherical sandwich shell representing the general structure of the skull bones as being the compact inner and outer tables separated by a porous diploë layer. The brain and surrounding cerebrospinal fluid are modeled as an acoustic fluid with properties similar to those of water. The fluid-shell system is subjected to a local axisymmetric and arbitrary time-dependent external pulse and the transient response of the system is determined by numerical methods. The effect of pulse duration is investigated by choosing the pulse as the Heaviside function. Pulses with short duration are found to be less damaging as far as skull fracture and brain injury are concerned. Human head impact tolerance curves are obtained. For the second part of the investigation, a more realistic pulse containing both exponential and sine components is chosen to study the responses of the models of the human head and four species of primates. The numerical results are obtained for the same magnitude of the pulse as well as for equal magnitudes of initial acceleration after impact.

Animals↗