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Biomedical subjects

J Hoare

Publications and source records attributed to J Hoare.

6 recordsLinked to original sources
PubMed1989

A strain-gauge study of the effect of external fixation on the canine tibia.

Electrical resistance rosette strain gauges bonded directly to the surface of the midshaft of the normal canine tibia were utilized to study the effect of the AO external skeletal fixator on the magnitude and orientation of the peak strain values recorded during locomotion. The application of the fixator in a single lateral bar configuration resulted in a significant decrease in surface bone strain magnitude but in only minor changes in the orientation of those strains. However, in only one of three dogs tested did the addition of a second external connecting bar result in significant further decreases in bone strain.

Animals↗
PubMed1988

A technique for electrically induced perturbation of rhythmic leg movement.

The paper describes electrical circuitry which replaces a mechanical brake, for perturbation of the contractile load of the legs during pedalling. The turning flywheel of an ergometer is connected to an alternator, with the electrical load provided by a power resistor connected across the output terminals. A 12-V battery provides the field current. Through variable resistors the field current is altered under microprocessor control, providing different steady-state loads when pedalling and also sudden transient changes of load. The point of change in load in the movement cycle can be accurately selected. The ergometer is instrumented for accurate measurement of pedal crank position, crank angular velocity and reaction force at the foot, to provide a physical description of the evoked steady states and transients, using microprocessor controlled sampling. The results show that the technique has application to the study of the range of reflex responses within a movement cycle and also to the more complex restoration of a movement pattern over a number of cycles. It is applicable to investigation of normal and diseased states.

Electronics↗
PubMed1988

Practical preparation and deblocking conditions for N-alpha-(2-(p-biphenylyl)-2-propyloxycarbonyl)-amino acid (N-a-Bpoc-Xxx-OH) derivatives.

Reproducible preparations are given for salts of the following L-amino acid derivatives: Bpoc-Ala-OH, Bpoc-Arg(Mtr)-OH, Bpoc-Asn-OH, Bpoc-Asp(OtBu)-OH, Bpoc-Cys(Acm)-OH, Bpoc-Cys(S-tBu)-OH, Bpoc-Gln-OH, Bpoc-Glu(OtBu)-OH, Bpoc-Gly-OH, Bpoc-Ile-OH, Bpoc-Leu-OH, N-alpha-Bpoc-Lys(epsilon-Boc)-OH, Bpoc-Met-OH, Bpoc-Phe-OH, Bpoc-Pro-OH, Bpoc-Ser(OtBu)-OH, Bpoc-Thr(OtBu)-OH, Bpoc-Tyr-OH, Bpoc-Val-OH. A study of the deblocking of N-alpha-Bpoc peptides in dichloromethane containing 0.5% trifluoroacetic acid revealed that a rapid equilbrium is established between the first-formed monomeric alkene 2-p-biphenylylpropene and the hindered dimer 2,4-bis(p-biphenylyl)-4-methyl-1-pentene. Thioethers were found to be inefficient carbocation scavengers for the deblocking reaction. The most efficient scavengers were found to be thiophenol and benzyl mercaptan, and the following approximate reactivity order was established: benzyl mercaptan approximately thiophenol greater than indole much greater than 1,3-dimethoxybenzene approximately resorcinol greater than 1,3,5-trimethoxybenzene approximately dimethyl sulfide approximately thioanisole.

Amino Acids↗
PubMed1977

Telemetric measurements of strain in the metacarpus of the horse: a pilot study.

The advances made by the use of a telemetric system in the study of bone strain in a free-moving horse are reported. A rosette strain gauge was bonded to the craniomedial aspect of the metacarpus of the horse. Attachment of a miniature FM transmitter to lead wires facilitated telemetric transmission of of resistance changes which corresponded to limb movement. During 3 different gaits, the trace pattern remained similar, although frequency and amplitude varied. The tracings were similar to those reported in other species in which nontelemetric transmission was used.

Animals↗