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Medical Science Monitor Basic Research has been selected for the ESCI - Emerging Sources Citation Index (Thomson Reuters, Web of Science, ISI), launching in November 2015 as a new edition of the Web of read more

Published: 2016-01-21

Mechanical Characterization of Immature Porcine Brainstem in Tension at Dynamic Strain Rates

Hui Zhao, Zhiyong Yin, Kui Li, Zhikang Liao, Hongyi Xiang, Feng Zhu

(Chongqing Key Laboratory of Vehicle/Biological Crash Security, Research Institute for Traffic Medicine, Daping Hospital, Third Military Medical University, Chongqing, China (mainland))

Med Sci Monit Basic Res 2016; 22:6-13

DOI: 10.12659/MSMBR.896368

BACKGROUND: Many brain injury cases involve pediatric road traffic accidents, and among these, brainstem injury causes disastrous outcomes. A thorough understanding of the tensile characterization of immature brainstem tissue is crucial in modeling traumatic brain injury sustained by children, but limited experimental data in tension is available for the immature brain tissue at dynamic strain rates.
MATERIAL AND METHODS: We harvested brainstem tissue from immature pigs (about 4 weeks old, and at a developmental stage similar to that of human toddlers) as a byproduct from a local slaughter house and very carefully prepared the samples. Tensile tests were performed on specimens at dynamic strain rates of 2/s, 20/s, and 100/s using a biological material instrument. The constitutive models, Fung, Ogden, Gent, and exponential function, for immature brainstem tissue material property were developed for the recorded experimental data using OriginPro® 8.0 software. The t test was performed for infinitesimal shear modules.
RESULTS: The curves of stress-versus-stretch ratio were convex in shape, and inflection points were found in all the test groups at the strain of about 2.5%. The average Lagrange stress of the immature brainstem specimen at the 30% strain at the strain rates of 2, 20, and 100/s was 273±114, 515±107, and 1121±197 Pa, respectively. The adjusted R-Square (R2) of Fung, Ogden, Gent, and exponential model was 0.820≤R2≤0.933, 0.774≤R2≤0.940, 0.650≤R2≤0.922, and 0.852£R2£0.981, respectively. The infinitesimal shear modulus of the strain energy functions showed a significant association with the strain rate (p<0.01).
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Keywords: Brain Injuries, Brain Stem, Viscoelastic Substances

Published: 2016-01-07

Cognition Regulated by Emotional Decision Making

George B. Stefano

Med Sci Monit Basic Res 2016; 22:1-5

DOI: 10.12659/MSMBR.897194

Published: 2015-12-31

Device Conformability and Morphological Assessment After TEVAR for Aortic Type B Dissection: A Single-Cen...

Moritz S. Bischoff, Matthias Müller-Eschner, Katrin Meisenbacher, Andreas S. Peters, Dittmar Böckler

Med Sci Monit Basic Res 2015; 21:262-270

DOI: 10.12659/MSMBR.897010