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Biomedical subjects

M N Leeming

Publications and source records attributed to M N Leeming.

12 recordsLinked to original sources
PubMed1994

Investigating cardiovascular responses during social interactions.

Measurements on cardiovascular parameters can be obtained conveniently with a number of contemporary biomedical monitors and instruments. The researcher seeks to analyze and interpret these measurements in the context of cardiovascular responses to social interactions so that social interactions can be adjusted to support the recovery of the cardiovascular patient. In contrast to large group, intersubject designs that rely on group averages, the author encourages the researcher to explore single-subject, or "small N," experimental designs to provide an intrasubject investigation based on repeated measures before, during, and after social interactions. Statistical control charts may provide an operational definition for special cause variation that the researcher wishes to detect. Some control chart precautions are addressed, especially as regard autocorrelated data. References are provided to assist the researcher in the design and exploratory use of the basic charts and modifications thereof.

Cardiovascular Diseases↗
PubMed1991

Transformation of Corynebacterium pseudotuberculosis by electroporation.

Corynebacterium pseudotuberculosis was transformed by electroporation, using pNG2, an erythromycin-resistance plasmid from C diphtheriae. Corynebacterium pseudotuberculosis cultivated in brain-heart infusion broth was washed 3 times with water, and resuspended to a final concentration of about 5 x 10(13) colony-forming units/ml. An electroporator constructed in our laboratory incorporated an electrode with 0.8-mm interelectrode gap, using disposable spectrophotometer cuvettes as containers for electroporation. The pNG2 was prepared in Escherichia coli and 4 to 16 micrograms of pNG2 DNA was mixed with 400-microliters amounts of cell suspension in prechilled cuvettes. After incubation on ice for 5 to 10 minutes, the mixture was electroporated at field strengths of up to 18 kV/cm, mixed with 1.5 ml of brain-heart infusion broth, and incubated at 37 C for 2 hours with agitation. Aliquots were then plated on brain-heart infusion blood agar with 15 micrograms of erythromycin/ml. Corynebacterium pseudotuberculosis was transformed at a maximal efficiency of approximately 4 x 10(4) transformants/micrograms of pNG2 DNA. Most total transformants and most transformants per microgram of pNG2 were generated at a field strength of 18 kV/cm. When the concentration of pNG2 DNA was varied, the average total number of transformants increased through a concentration of 30 micrograms/ml, but the efficiency of transformation was highest at the lowest DNA concentration. Transformants contained unmodified pNG2.

Animals↗
PubMed1986

Licking patterns for sucrose solutions by young and aged squirrel monkeys.

The licking elicited by 0.1, 0.3, and 1.0 M sucrose solutions was measured in six young and six aged squirrel monkeys. All tongue-on and tongue-off times were recorded in addition to conventional measures of lick rate and consumption. Consummatory activity by both groups increased monotonically with sucrose concentration. Aged monkeys displayed greater within animal variability of tongue-on times than did young monkeys. Distributions of pause lengths between licking bursts contained two components, one varying inversely with sucrose concentration, the other varying inversely with age. Distributions of licks per burst contained a component that increased with sucrose concentration but none varying with age. Results indicated that licking deteriorated little with age and that consumption is controlled mainly by length and spacing of bursts, not by individual lick parameters.

Aging↗
PubMedDate not supplied

A probabilistic approach to safety design: the two-element environment.

The immediate electrical surroundings of the hospitalized patient are comprised of elements which may or may not be powered by electricity. Four electrical "operators"--G, E, T, and C--indicate respectively the status of the grounding of elements, the electrical leakage of elements, the electrical contact of one element with another, and the electrical contact of the patient with the elements. The operators are considered as mutually stochastically independent indicator random variables. The operators are utilized to formulate the probability of electrical danger in a basic environment of 2 elements. Grounding concepts of electrical safety are questioned as the operators, when supplied with probabilities, demonstrate a range of situations over which an ungrounding strategy may provide more safety than one of grounding. The probablisitic model calls for the collection and analysis of electrical data from which estimates of probabilities may be obtained and with which electrical models may be refined.

Accident Prevention↗