Biomedical subjects

R E Hannah

Publications and source records attributed to R E Hannah.

7 recordsLinked to original sources

PubMed1995

Comparison of high-performance liquid chromatography and capillary zone electrophoresis in penciclovir biodegradation kinetic studies.

High-performance liquid chromatography (HPLC) and capillary zone electrophoresis (CZE) were used in biodegradation kinetic studies. This paper describes a rapid penciclovir separation using CZE with detection limits comparable to HPLC. The ionic-strength mediated stacking technique was employed while good resolution was maintained. With a shorter analysis time, comparable detection limits and no organic solvent consumption, CZE is a better method for penciclovir biodegradation studies than conventional reversed-phase HPLC (RP-HPLC).

Acyclovir↗

PubMed1987

The effect of cyclohexene, a preservative in dichloromethane on the liquid-liquid extraction and analysis of chlorinated drinking water.

Liquid-liquid extraction with dichloromethane is the Environmental Protection Agency's (EPA) method of choice for the analysis of acid or base neutral organic chemicals in water. Free radical chlorination and oxidation products of cyclohexene (the solvent preservative) in dichloromethane have been observed in extracts of chlorinated drinking water (after 10(5) fold concentration) by gas chromatography and gas chromatography-mass spectrometry. The chlorinated cyclohexene derivatives limit the quantitative and qualitative analysis of compounds eluting at Kovát's index less than 700-1000 and the use of these extracts for organoleptic and mutagenic studies. The effect of residual free chlorine in water on the cyclohexene present in the solvent was studied. Over ten cyclohexene derivatives were produced in every case when any residual free chlorine was present in the water. When chlorine is reduced to chloramine, the cyclohexene derivatives were greatly reduced in number and amount.

Chloramines↗

PubMed1985

The Canadian collar: a new cervical spine orthosis.

We developed a cervical collar (the Canadian collar) in response to the requirements of occupational therapists who manage arthritis patients. This orthosis overcomes the problems of heat and inadequate support common to many soft collars. The collar is constructed from nylon and polyvinyl chloride tubing, clipped together by nylon junctions, and from chin and breastplate supports of molded nylon rod. Preliminary clinical trials have been conducted on 20 patients, 15 of whom had arthritis. An additional 60 patients with various disabilities have been fitted. The collar has been readily accepted by patients, therapists, orthotists, and physicians.

Adolescent↗

PubMed1984

Kinematic symmetry of the lower limbs.

This study examined the extent of kinematic symmetry of lower limbs when walking. Twelve able-bodied subjects were measured with a device which recorded three-dimensional motion of hip and knee joints bilaterally. Comparisons of right and left sagittal, transverse, and coronal plane motions were conducted in the time and frequency domains, and indices were developed to express these symmetries in each domain. In both domains high levels of symmetry were observed for the sagittal plane motions of hips and knees. High symmetry was also observed for the hip transverse and coronal plane motions, but symmetry was lower for these planes at the knee. Low standard deviations for the group occurred where symmetry was high. Reduced symmetry in the transverse and coronal planes was attributed to the lower signal to noise ratio for these planes. While experimental technique could be improved by better data collection procedures and by different analytic procedures, the study concluded that the able-bodied individual walks with reasonable symmetry at the hips and knees. These data formed a suitable baseline for comparison with pathologic gait data.

Adult↗

PubMed1984

Prostheses alignment: effect on gait of persons with below-knee amputations.

This study investigated the effect on gait of changing prosthetic alignment for five people with amputations. Three-dimensional angular kinematic data were recorded by electrogoniometers positioned at their hips and knees. Indices of symmetry were developed in time and frequency domains for motion data of lower limbs when walking. These measures of symmetry were determined at different prostheses alignment settings and used to assess the possibility of aligning below-knee prostheses on the basis of symmetry of lower limb motion. Optimal or neutral alignment of below-knee prosthesis, as selected by clinically experienced personnel, tended to minimize asymmetry of gait at the hips and knees for persons with below-knee amputations. The indices of symmetry showed that alignment changes to the prosthetic foot disrupt gait to a greater extent than do other alignment changes. Asymmetries of hip flexion-extension motions were more sensitive to alignment changes than were other asymmetries. An index was selected that showed sensitivity to changes in gait caused by changes in prosthetic alignment for below-knee amputations. Refinements and other applications of this index in rehabilitation are suggested.

Artificial Limbs↗

PubMed1983

Structural matrices for use in rehabilitation.

Progress is reported on the development and application of structural matrices in rehabilitation. The development of a stronger and more adjustable matrix than was previously reported is detailed, together with the principles necessary to achieve this. Application of this new matrix to adult seating is described. The emergence of programmable beams and the need for containment matrices are also documented and the advantages of these approaches to a variety of problems in rehabilitation are given.

Biomedical Engineering↗

PubMed1983

Tubular orthoses.

A method of constructing orthoses and other patient devices using nylon tubing and clip-together standard components is described. This permits the rapid assembly of custom orthoses that can be evaluated before prescription in a clinical setting. These orthoses have been successfully used for the control of thoracic spinal flexion, hip abduction, elbow extension, shoulder abduction, cervical spine stabilization and pressure sore relief. Advantages over existing orthoses include reduced weight, improved comfort and cosmesis, low cost and increased speed of provision. Examples of these orthoses are shown, together with details of their structure, function and clinical results.

Adult↗