scholarly journals Biaxial mechanical properties of human vocal fold cover under vocal fold elongation

2017 ◽  
Vol 142 (4) ◽  
pp. EL356-EL361 ◽  
Author(s):  
Zhaoyan Zhang ◽  
Himadri Samajder ◽  
Jennifer L. Long
Keyword(s):  
Mechanical Properties ◽  
Vocal Fold ◽  
Biaxial Mechanical Properties ◽  
Fold Cover

Videostrobolaryngoscopy of Mucus Layer during Vocal Fold Vibration in Patients with Laryngeal Tension-Fatigue Syndrome

2002 ◽  
Vol 111 (6) ◽  
pp. 537-541 ◽  
Author(s):  
Tzu-Yu Hsiao ◽  
Chia-Ming Liu ◽  
Kai-Nan Lin
Keyword(s):  
Mechanical Properties ◽  
Vocal Fold ◽  
Rough Surfaces ◽  
Voice Disorders ◽  
Vocal Folds ◽  
Voice Disorder ◽  
Mucus Layer ◽  
Vocal Fold Vibration ◽  
Fatigue Syndrome ◽  
Functional Dysphonia

The mucus layer on the vocal folds was examined by videostrobolaryngoscopy in patients with laryngeal tension-fatigue syndrome, a chronic functional dysphonia due to vocal abuse and misuse. Besides the findings in previous reports (such as abnormal glottal closure, phase or amplitude asymmetry, and the irregular mucosal wave), the vocal folds during vibration had an uneven mucus surface. The occurrence of an uneven mucus layer on vocal folds was significantly greater in subjects with this voice disorder (83% or 250 of 301 patients in this series) than in those without voice disorders (18.5% or 5 of 27). The increase of mucus viscosity, mucus aggregation, and the formation of rough surfaces on the vocal folds alter the mechanical properties that contribute to vibration of the cover of the vocal folds, and thereby worsen the symptoms of dysphonia in patients with laryngeal tension-fatigue syndrome.

Biaxial Mechanical Properties of Passive Right Ventricular Free Wall Myocardium

1993 ◽  
Vol 115 (2) ◽  
pp. 202-205 ◽  
Author(s):  
M. S. Sacks ◽  
C. J. Chuong
Keyword(s):  
Mechanical Properties ◽  
Right Ventricular ◽  
Mechanical Response ◽  
Ventricular Free Wall ◽  
Fiber Direction ◽  
Free Wall ◽  
Right Ventricular Free Wall ◽  
Tissue Specimens ◽  
Excised Tissue ◽  
Biaxial Mechanical Properties

The biaxial mechanical properties of right ventricular free wall (RVFW) myocardium were studied. Tissue specimens were obtained from the sub-epicardium of potassium-arrested hearts and different stretch protocols were used to characterize the myocardium’s mechanical response. To assess regional differences, we excised tissue specimens from the conus and sinus regions. The RVFW myocardium was found to be consistently anisotropic, with a greater stiffness along the preferred (or averaged) fiber direction. The anisotropy in the conus region was more pronounced than in the sinus region. A comparison with studies of left ventricle (LV) midwall myocardium revealed that, 1) the fiber direction stiffnesses are greater in the RVFW than in the LV, 2) the degree of anisotropy is greater in the RVFW than in the LV.

A Comparison of Uniaxial and Biaxial Mechanical Properties of the Annulus Fibrosus: A Porcine Model

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Diane E. Gregory ◽  
Jack P. Callaghan
Keyword(s):  
Mechanical Properties ◽  
Annulus Fibrosus ◽  
Axial Direction ◽  
Stretch Ratio ◽  
Intervertebral Disk ◽  
Circumferential Direction ◽  
Biaxial Tests ◽  
Maximal Stress ◽  
Biaxial Mechanical Properties

The annulus fibrosus of the intervertebral disk experiences multidirectional tension in vivo, yet the majority of mechanical property testing has been uniaxial. Therefore, our understanding of how this complex multilayered tissue responds to loading may be deficient. This study aimed to determine the mechanical properties of porcine annular samples under uniaxial and biaxial tensile loading. Two-layer annulus samples were isolated from porcine disks from four locations: anterior superficial, anterior deep, posterior superficial, and posterior deep. These tissues were then subjected to three deformation conditions each to a maximal stretch ratio of 1.23: uniaxial, constrained uniaxial, and biaxial. Uniaxial deformation was applied in the circumferential direction, while biaxial deformation was applied simultaneously in the circumferential and compressive directions. Constrained uniaxial consisted of a stretch ratio of 1.23 in the circumferential direction while holding the tissue stationary in the axial direction. The maximal stress and stress-stretch ratio (S-S) moduli determined from the biaxial tests were significantly higher than those observed during both the uniaxial tests (maximal stress, 97.1% higher during biaxial; p=0.002; S-S moduli, 117.9% higher during biaxial; p=0.0004) and the constrained uniaxial tests (maximal stress, 46.8% higher during biaxial; S-S moduli, 82.9% higher during biaxial). These findings suggest that the annulus is subjected to higher stresses in vivo when under multidirectional tension.

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