dc.contributor.author |
Taberner, Andrew |
en |
dc.contributor.author |
Han, June |
en |
dc.contributor.author |
Loiselle, Denis |
en |
dc.contributor.author |
Nielsen, Poul |
en |
dc.date.accessioned |
2011-12-04T22:41:28Z |
en |
dc.date.accessioned |
2011-12-08T18:22:23Z |
en |
dc.date.issued |
2011 |
en |
dc.identifier.citation |
Journal of Applied Physiology 11(6) pp. 1798-1803 Dec 2011 |
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dc.identifier.issn |
8750-7587 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/9903 |
en |
dc.description.abstract |
We describe a unique work-loop calorimeter with which we can measure, simultaneously, the rate of heat production and force-length work output of isolated cardiac trabeculae. The mechanics of the force-length work-loop contraction mimic those of the pressure-volume work-loops experienced by the heart. Within the measurement chamber of a flow-through microcalorimeter, a trabecula is electrically stimulated to respond, under software control, in one of three modes: fixed-end, isometric, or isotonic. In each mode, software controls the position of a linear motor, with feedback from muscle force, to adjust muscle length in the desired temporal sequence. In the case of a work-loop contraction, the software achieves seamless transitions between phases of length control (isometric contraction, isometric relaxation, and restoration of resting muscle length) and force control (isotonic shortening). The area enclosed by the resulting force-length loop represents the work done by the trabecula. The change of enthalpy expended by the muscle is given by the sum of the work term and the associated amount of evolved heat. With these simultaneous measurements, we provide the first estimation of suprabasal, net mechanical efficiency (ratio of work to change of enthalpy) of mammalian cardiac trabeculae. The maximum efficiency is at the vicinity of 12%. |
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dc.format.medium |
6 |
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dc.relation.ispartofseries |
Journal of Applied Physiology |
en |
dc.relation.replaces |
http://hdl.handle.net/2292/9762 |
en |
dc.relation.replaces |
2292/9762 |
en |
dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from
http://www.sherpa.ac.uk/romeo/issn/0021-8987/ |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
en |
dc.subject |
work heat enthalpy efficiency microcalorimeter |
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dc.title |
An innovative work-loop calorimeter for in vitro measurement of the mechanics and energetics of working cardiac trabeculae |
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dc.type |
Journal Article |
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dc.identifier.doi |
10.1152/japplphysiol.00752.2011 |
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pubs.begin-page |
1798 |
en |
pubs.volume |
111 |
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dc.rights.holder |
Copyright: American Physiological Society |
en |
dc.identifier.pmid |
21903883 |
en |
pubs.end-page |
1803 |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
JOUR |
en |
pubs.elements-id |
225013 |
en |
pubs.org-id |
Bioengineering Institute |
en |
pubs.org-id |
ABI Associates |
en |
pubs.org-id |
Engineering |
en |
pubs.org-id |
Engineering Science |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Science Research |
en |
pubs.org-id |
Maurice Wilkins Centre (2010-2014) |
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pubs.record-created-at-source-date |
2011-12-04 |
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pubs.dimensions-id |
21903883 |
en |