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Biomedical subjects

L D Nokes

Publications and source records attributed to L D Nokes.

At least 19 recordsLinked to original sources
PubMed2001

The potential and limitations of utilising head impact injury models to assess the likelihood of significant head injury in infants after a fall.

The use of engineering principles in assessing head injury scenarios is of increasing significance in investigations into suspected child abuse. A fall scenario is often given as the history for a head injury to an infant. This paper addresses the basic engineering principles and factors to be considered when calculating the severity of a head impact after free-fall. The application of head injury models (HIMs) to ascertain the forces involved in childhood head injuries from impact is also discussed. Previous studies including Duhaime et al. [J. Neurosurg. 66 (1987) 409] and Nokes et al. [Forensic Sci. Int. 79 (1995) 85] have utilised HIMs for this purpose: this paper reviews those models most widely documented.The HIM currently considered the 'state-of-the-art' is the head injury criterion (HIC) and it is suggested that this model should be utilised for assessing head impact injury in child abuse cases where appropriate.

Acceleration↗
PubMed2001

A biomechanical reconstruction of a wound caused by a glass shard--a case report.

During the course of a criminal trial, an investigating pathologist is commonly asked how much force was required to produce an injury. This subjective opinion is based on the pathologist's previous experience of dealing with wounds inflicted with similar weapons. However, in the case of stab wounds inflicted by broken glass, it is unlikely that two glass fragments would be physically similar. In the case studied, two theories were examined: that a wound resulted from a thrown glass fragment or that it had been caused as a stab injury by the glass held in the bare hand. The investigation involved quantifying the energy required for human tissue penetration, comparison of sharpness, a biomechanical analysis of throwing actions and testing of the hypothesis that if the glass shard were used as a stabbing implement it would result in a cut to the hand.The investigation utilised a scientific methodology that reduced the need for speculative (though informed) opinion from the pathologist by producing quantitative results.

Biomechanical Phenomena↗
PubMed2001

A novel approach to forensic investigation: three-dimensional kinematic and kinetic motion analysis.

Following a domestic incident, a five-year-old child was pronounced dead on arrival at hospital. The subsequent post-mortem examination found that the cause of death was peritonitis as a result of a rupture of the duodenum. During the police interview, the main suspect alleged that the injury occurred whilst playing a game which involved standing on the child's abdomen and chest. A reconstruction of the game was performed using 3-dimensional kinematic and kinetic motion analysis to investigate the feasibility of the statement as described by the defendant. Presented is a summary of the investigation together with a description of kinematic and kinetic methods employed.

Journal Article↗
PubMed2000

Observation on the recent examination of bones from St David's Cathedral.

Bones discovered in 1866 walled up in St David's Cathedral, West Wales were thought possibly to be those of St David and his companion St Justinian, both of whom died in the late 6th or early 7th century. Examination and radio carbon dating of the bones suggested that these were not from St David nor St Justinian. Some of the bones could be the remains of St Caradoc, a 12th century hermit. It is likely, however, that the bones are remains of clergy who, for reasons not yet understood, were re-interred into the wall.

Christianity↗
PubMed2000

Subjective assessment of blunt impacts.

An important role of an eyewitness to an assault is to effectively quantify the degree of force used; yet evidence of this form is often subjective and relies on personal opinion. Twelve subjects were asked to strike a load cell with a wooden bat, using varying degrees of force. The strikes were recorded by video camera and 50 people observed the video and were asked to grade the strikes. On average 44% accurately assessed the severity of the strikes, whilst 26% over-estimated. Results suggest that the evidence of eyewitnesses should be treated with caution.

Adult↗
PubMed1999

Dynamics of stab wounds: force required for penetration of various cadaveric human tissues.

It is often said that once the skin has been penetrated no further force is required to produce penetration of underlying tissues. This experimental study has used technology which was not available to earlier investigators to examine this issue in detail. The results confirm the importance of skin penetration but indicate that the penetration of other tissues may also require significant force.

Adipose Tissue↗
PubMed1999

Biomechanics of judicial hanging: a case report.

A prisoner in Washington State in the United States of America appealed against sentence of death by hanging on the grounds that it was 'cruel and unusual' and hence contravened the Eighth Amendment of the US Constitution. The man weighed 184 kg (406 lb) and it was suggested that the 'drop' proposed to effect judicial hanging might result in decapitation. This hypothesis was tested by applying simple biodynamic principles to the available data from past hangings. It was concluded that decapitation was a significant possibility.

Adult↗
PubMed1999

The use of low-frequency vibration measurement in orthopaedics.

This paper reviews the literature regarding the use of applying conventional low-frequency vibration analysis as a possible diagnostic tool in the orthopaedic field. Although a considerable number of investigations have been carried out, including the effects of soft tissue, the technique has not been widely accepted clinically. The application of ultrasound appears to be a more realistic alternative.

Aged↗
PubMed1999

The use of ultrasonics in orthopaedics--a review.

Ultrasonic testing of bones has been used with varying degrees of success for more than 40 years to determine mechanical properties of bone tissue and strength of whole bones. Ultrasound has also been used in an effort to develop non-invasive techniques for monitoring fracture healing in long bones. Despite early promising results, clinically useful methods have yet to be developed. This paper provides a comprehensive review of the literature of determining mechanical properties of bone and the monitoring of fracture healing.

Biomechanical Phenomena↗
PubMed1995

Postmortem electrical excitability of skeletal muscle: preliminary investigation of an animal model.

Presented is a preliminary study of the feasibility of using an animal model to investigate the postmortem time-dependent decay in muscular response, when subjected to electrical stimulation and to develop an animal model for the assessment of the use of electrical excitability as a method for determining the postmortem period of a human corpse. Analysis of the results shows a correlation between the rate of decay of muscular response with the postmortem interval.

Animals↗
PubMed1992

The use of either the nose or outer ear as a means of determining the postmortem period of a human corpse.

Presented in this paper are the initial results involving the use of the nose or outer ear as temperature measurement sites to determine the postmortem period of the human corpse. Simple mathematical models for both sites are developed based on cooling curves of five corpses. Analysis of errors between actual and calculated postmortem intervals suggest that in its present form, the described methods would not be suitable for use in accurately determining the time since death of human corpses.

Body Temperature↗
PubMed1991

Detection of internal fixation plate loosening by means of an analysis of vibratory responses.

This paper reports an in vitro investigation of a non-invasive method for detecting the loosening of internal fixation plates. The technique involves the electromechanical vibration of the fixation plate and the electromagnetic detection of its vibratory response. Frequency domain analysis of both fixed and loosened plates are compared and spectral artefacts are suggested as a means of classifying the mode and extent of plate loosening. An algorithm for the diagnosis of loose plates using the new approach is included.

Algorithms↗
PubMed1988

Estimation of the post mortem period by multiple-site temperature measurements and the use of a new algorithm.

The estimation of the post mortem period, in cases where death occurred under suspicious circumstances, is usually attempted using temperature measurements taken at a single body site. Early investigations of the validity of such an approach use the abdominal skin surface, the axilla and the rectum as measurement sites (B.H. Knight, Forensic Sci. Int., 36 (1987) 47-55). However, it has recently become more common to use the rectum alone, though the ear and the nasal passages have also been utilized. Whatever site is employed, the estimates are frequently found to be inaccurate. There are several fundamental reasons for these inaccuracies, the most prominent being the unknown variation in the ambient temperature between the time of death and the commencement of measurements, and the unknown body temperature at the time of death. This paper proposes a method of overcoming the above difficulties by taking a series of measurements concurrently at a number of body sites, a technique used by several previous workers (B.H. Knight, Forensic Sci. Int., 36 (1987) 47-55). Initial investigations have shown that an improved estimation of post mortem period is obtainable by the application of a suitable decision-making algorithm.

Algorithms↗
PubMed1988

Vibrations in orthopedics.

Measurements of various mechanical properties of skeletal material using vibration techniques have been reported. The purposes of such investigations include the monitoring of pathogenic disorders such as osteoporosis, the rate and extent of fracture healing, and the status of internal fixations. Early investigations pioneered the application of conventional vibration measurement equipment to biological systems. The more recent advent of the microcomputer has made available to research groups more sophisticated techniques for data acquisition and analysis. The economical advantages of such equipment has led to the development of portable research instrumentation which lends itself to use in a clinical environment. This review article reports on the developments and progression of the various vibrational techniques and theories as applied to musculoskeletal systems.

Biomechanical Phenomena↗