IN VITROACOUSTIC WAVE PROPAGATION IN HUMAN AND BOVINE CANCELLOUS BONE AS PREDICTED BY BIOT'S THEORY

2008 ◽  
Vol 08 (02) ◽  
pp. 183-201 ◽  
Author(s):  
LUIS CARDOSO ◽  
ALAIN MEUNIER ◽  
CHRISTIAN ODDOU
Keyword(s):  
Wave Propagation ◽  
Wave Velocity ◽  
Cancellous Bone ◽  
Slow Wave ◽  
Mass Density ◽  
Bone Mass Density ◽  
Biot’S Theory ◽  
Structural Index ◽  
Biot's Theory ◽  
Wave Velocities

Recent in vitro studies have provided evidence of the propagation of two different longitudinal wave modes at ultrasonic frequencies in cancellous bone. The genesis of these two plane waves in fluid-saturated porous media is predicted by the poroelastic approach to wave propagation originally developed by Biot. However, wave velocity is usually analyzed as a function of bone mass density only; therefore, the influence of the cancellous bone microstructure over the wave velocity is not taken into account. In the present study, a descriptor of the microstructure is considered in Biot's theory. This model is used to evaluate the large experimental variability of both fast and slow wave velocities measured on randomly oriented human and bovine cancellous bone samples. The role of the anisotropic solid structure and fluid in the behavior of fast and slow wave velocities is examined. Experimental and theoretically predicted velocities are found in close agreement when analyzed as a function of both porosity and structural index. This model has the potential to be used to determine an acoustically derived structural index in cancellous bone.

Wave propagation in cancellous bone in terms of Biot's theory

2008 ◽  
Vol 123 (5) ◽  
pp. 3513-3513
Author(s):  
Michal Pakula ◽  
Frederic Padilla ◽  
Mariusz Kaczmarek ◽  
Pascal Laugier
Keyword(s):  
Wave Propagation ◽  
Cancellous Bone ◽  
Biot’S Theory ◽  
Biot's Theory

scholarly journals Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss

2015 ◽  
Vol 227 (3) ◽  
pp. 129-141 ◽  
Author(s):  
Russell T Turner ◽  
Michael Dube ◽  
Adam J Branscum ◽  
Carmen P Wong ◽  
Dawn A Olson ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Body Weight ◽  
Bone Loss ◽  
Bone Mass ◽  
Bone Turnover ◽  
Cancellous Bone ◽  
Mass Density ◽  
Female Rats ◽  
Bone Mass Density ◽  
Age Related

Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin,n=7) or a control vector encoding green fluorescent protein (rAAV-GFP,n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (−4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (−80%), serum leptin (−77%), and serum IGF1 (−34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover.

scholarly journals Axially Symmetric Vibrations of Composite Poroelastic Spherical Shell

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Rajitha Gurijala ◽  
Malla Reddy Perati
Keyword(s):  
Wave Propagation ◽  
Phase Velocity ◽  
Spherical Shell ◽  
Wave Number ◽  
Biot’S Theory ◽  
Impervious Surfaces ◽  
Axially Symmetric ◽  
Spherical Shells ◽  
Biot's Theory

This paper deals with axially symmetric vibrations of composite poroelastic spherical shell consisting of two spherical shells (inner one and outer one), each of which retains its own distinctive properties. The frequency equations for pervious and impervious surfaces are obtained within the framework of Biot’s theory of wave propagation in poroelastic solids. Nondimensional frequency against the ratio of outer and inner radii is computed for two types of sandstone spherical shells and the results are presented graphically. From the graphs, nondimensional frequency values are periodic in nature, but in the case of ring modes, frequency values increase with the increase of the ratio. The nondimensional phase velocity as a function of wave number is also computed for two types of sandstone spherical shells and for the spherical bone implanted with titanium. In the case of sandstone shells, the trend is periodic and distinct from the case of bone. In the case of bone, when the wave number lies between 2 and 3, the phase velocity values are periodic, and when the wave number lies between 0.1 and 1, the phase velocity values decrease.

Modeling of Ultrasonic Wave Propagation Path through Cancellous Bone and Quantitative Estimation of Bone Density and Bone Quality

2006 ◽  
Vol 321-323 ◽  
pp. 857-861
Author(s):  
Takahiko Otani
Keyword(s):  
Bone Density ◽  
Bone Mass ◽  
Ultrasonic Wave ◽  
Cancellous Bone ◽  
Mass Density ◽  
Propagation Path ◽  
Bone Mass Density ◽  
Ultrasonic Wave Propagation ◽  
Fast And Slow Waves ◽  
Ultrasonic Parameters

Osteoporosis is a disease characterized by decreasing bone density, and is assessed by the bone mass density of cancellous bone. An X-ray method is widely used for noninvasive measurement of bone mass density [mg/cm3]. An ultrasonic method has the potential to evaluate the elastic properties, however measured ultrasonic parameters are the slope of frequency dependent attenuation (BUA [dB/MHz]) and the speed of sound (SOS [m/s]), not the bone mass density [mg/cm3]. In previous study, two longitudinal waves, the fast and slow waves, were observed in cancellous bone. In this study, the propagation path through cancellous bone is modeled to specify the causality between ultrasonic wave parameters and bone density. Then bone density and bone elasticity are quantitatively formulated. A novel ultrasonic bone densitometry, prototype LD-100, have been developed. The bone density [mg/cm3] and the bone elasticity [GPa] are evaluated by ultrasonic parameters based on the fast and slow waves in cancellous bone using a modeling of ultrasonic wave propagation path.

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