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Proceedings Paper

Effect of water content on specific heat capacity of porcine septum cartilage
Author(s): Yongseok Chae; Enrique J. Lavernia; Brian Jet-Fei Wong
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Paper Abstract

The effect of water content on specific heat capacity was examined using temperature modulated Differential Scanning Calorimetry (TMDSC). This research was motivated in part by the development laser cartilage reshaping operations, which use photothermal heating to accelerate stress relaxation and shape change. Deposition of thermal energy leads to mechanical stress relaxation and redistribution of cartilage internal stresses, which may lead to a permanent shape change. The specific heat of cartilage specimens (dia: 3 mm and thickness 1-2 mm) was measured using a heating rate of 2 degree(s)C/min for conventional DSC and 2 degree(s)C/min with an amplitude 0.38-0.45 degree(s)C and a period 60-100 sec for TMDSC. The amount of water in cartilaginous tissue was determined using thermogravimetry analysis (TGA) under ambient conditions. In order to correlate changes in heat flow with alterations in cartilage mechanical behavior, dynamic mechanical temperature analysis (DMTA) was used to estimate the specific transition temperatures where stress relaxation occurs. With decreasing water content, we identified a phase transition that shifted to a higher temperature after 35-45% water content was measured. The phase transition energy increased from 0.12 J/g to 1.68 J/g after a 45% weight loss. This study is a preliminary investigation focused on understanding the mechanism of the stress relaxation of cartilage during heating. The energy requirement of such a transition estimated using TMDSC and temperature range, where cartilage shape changes likely occur, was estimated.

Paper Details

Date Published: 27 June 2002
PDF: 10 pages
Proc. SPIE 4617, Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical, (27 June 2002); doi: 10.1117/12.472508
Show Author Affiliations
Yongseok Chae, Univ. of California/Irvine (United States)
Enrique J. Lavernia, Univ. of California/Irvine (United States)
Brian Jet-Fei Wong, Beckman Laser Institute and Medical Clinic (United States)

Published in SPIE Proceedings Vol. 4617:
Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical
Steven L. Jacques; Donald Dean Duncan; Sean J. Kirkpatrick; Andres Kriete; Donald Dean Duncan; Sean J. Kirkpatrick; Andres Kriete, Editor(s)

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