Frequency dependence of the acoustic radiation force function (Yp) for spherical targets for a wide range of materials

1981 ◽  
Vol 69 (6) ◽  
pp. 1618-1623 ◽  
Author(s):  
L. W. Anson ◽  
R. C. Chivers
Keyword(s):  
Frequency Dependence ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Force Function ◽  
Wide Range

Mechanotransductive Effects of Acoustic Radiation Force on Osteoblastic Primary Cilium, Cytoskeleton and Ca2+ Influx

2012 ◽  
Author(s):  
Y. X. Qin ◽  
S. Zhang ◽  
J. Cheng
Keyword(s):  
Primary Cilium ◽  
Bone Cells ◽  
Acoustic Radiation ◽  
Biological Effects ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Dependent Manner ◽  
Wide Range

Mechanotransduction has demonstrated potentials for tissue adaptation in vivo and in vitro. It is well documented that ultrasound, as a mechanical signal, can produce a wide variety of biological effects in vitro and in vivo[1]. For example, pulsed ultrasound can be used to accelerate the rate of bone fracture healing noninvasively. Although a wide range of studies have been done, mechanism for this therapeutic effect on bone healing is currently unknown and still under active investigation. In our previous studies, we have developed methodology allowed in vitro manipulating osteoblastic cells using acoustic radiation force (ARF) generated by ultrasound without the effects of acoustic streaming and ultrasound-induced temperature rise. Furthermore, we also confirmed that ARF modulated intracellular Ca2+ transient in MC3T3-E1 osteoblast-like cells in a strain and frequency-dependent manner. A potential mechanism by which bone cells may sense ultrasound is through their structures such as primary cilia and cytoskeletons. The purpose of the current study was to evaluate the hypothesis that acoustic radiation force can regulate the activities of the primary cilium and the cytoskeleton of the cells, which act as the mechanotransductive signals to mediate Ca2+ flux, as a pathway in response to cyclic loading.

ACOUSTIC RADIATION FORCE AND TORQUE ON A SOLID ELLIPTIC CYLINDER

2007 ◽  
Vol 15 (03) ◽  
pp. 377-399 ◽  
Author(s):  
SEYYED M. HASHEMINEJAD ◽  
R. SANAEI
Keyword(s):  
Boundary Conditions ◽  
Acoustic Radiation ◽  
Classical Method ◽  
Elliptic Cylinder ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Mathieu Functions ◽  
Steel Cylinder ◽  
Cross Sectional ◽  
Wide Range

Exact expressions for the acoustic radiation torque and force components experienced by elastic cylinders of elliptic cross-section immersed in ideal fluids and placed in a progressive or standing wave field is developed. The classical method of eigen-function expansion and the pertinent boundary conditions are employed to develop analytical expressions in the form of infinite series involving Mathieu and modified Mathieu functions. The complications arising due to the nonorthogonality of angular Mathieu functions corresponding with distinct wave numbers as well as problems associated with the appearance of additional angular dependent terms in the boundary conditions are all avoided in an elegant manner by expansion of the angular Mathieu functions in terms of transcendental functions and subsequent integration, leading to a linear set of independent equations in terms of the unknown scattering coefficients. Numerical calculations of the radiation force and torque function amplitudes are performed in a wide range of frequencies and cross-sectional eccentricities for a stainless steel cylinder submerged in water. Particular attention is paid to assessment of the effects of cross-sectional ellipticity as well as incident field asymmetry on the acoustic radiation force/torque acting on the elliptical cylinder. Limiting case involving an elastic circular or elliptic cylinder in an ideal fluid is considered and fair agreements with well-known solutions are established.

Acoustic Scattering and Radiation Force Function Experienced by Functionally Graded Cylindrical Shells

2011 ◽  
Vol 27 (2) ◽  
pp. 227-243 ◽  
Author(s):  
J. Jamali ◽  
M.H. Naei ◽  
F. Honarvar ◽  
M. Rajabi
Keyword(s):  
Acoustic Radiation ◽  
Micromechanical Model ◽  
Acoustic Scattering ◽  
Sound Field ◽  
Radiation Force ◽  
Functionally Graded ◽  
Force Function ◽  
Dynamical Response ◽  
Shell Wall ◽  
Wide Range

ABSTRACTA body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force. In this paper, the method of wave function expansion is adopted to study the scattering and the radiation force function caused by a plane normal harmonic acoustic wave incident upon an arbitrarily thick-walled functionally graded cylindrical shell submerged in and filled with compressible ideal fluids. A laminate approximate model and the so-called state space formulation in conjunction with the classical transfer matrix (T-matrix) approach are employed to present an analytical solution based on the two-dimensional exact equations of elasticity. Two typical models, representing the elastic properties of FGM interlayer, are considered. In both models, the mechanical properties of the graded shell are assumed to vary smoothly and continuously with the change of volume concentrations of the constituting materials across the thickness of the shell. In the first model, the simple rule of mixture governs. In the second, an elegant self-consistent micromechanical model which assumes an interconnected skeletal microstructure in the graded region is employed. Particular attention is paid on dynamical response of these models in a wide range of frequency and for different shell wall-thicknesses. In continue, by focusing on the second model, the normalized radiation force function and the form function amplitude are calculated and compared for different shell wall thicknesses and various profile of variations. Limiting cases are considered and good agreements with the solutions available in the literature are obtained.

Rationale Abklärung von Lebererkrankungen

2017 ◽  
Vol 74 (3) ◽  
pp. 79-86
Author(s):  
Leona von Köckritz ◽  
Andrea De Gottardi
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Alkalische Phosphatase ◽  
Gamma Glutamyltransferase ◽  
Alpha 1 Antitrypsin

Zusammenfassung. Im klinischen Alltag werden häufig erhöhte Leberwerte beobachtet. In der Regel erfordern sie weitere Abklärungen bezüglich der möglichen Ätiologie und des Schweregrad einer akuten oder chronischen Lebererkrankung. Die Abklärung sollte dabei neben einer gezielten Anamnese und sorgfältigen klinischen Untersuchung, auch die Bestimmung von laborchemischen Markern für Cholestase und Leberfunktionsstörungen (wie Alkalische Phosphatase, gamma-Glutamyltransferase, Bilirubin, Albumin und Gerinnungsfaktoren) umfassen. Die Bestimmung weiterer Parameter wie Ferritin und Transferrinsättigung, Autoimmunantikörper, Virusserologien, alpha-1 Antitrypsin und Coerulolasmin können weitere Hinweise für die kausalen Zusammenhänge der Leberfunktionsstörung liefern. Bei Patienten mit Lebererkrankungen ist eine sonografische Beurteilung der Leber obligat. Ergänzend zur Sonografie werden heute weitere nicht-invasive Methoden wie Fibroscan, Acoustic Radiation Force Impulse Elastometrie und Magnet-Resonanz-Elastografie zur Beurteilung der Leberfibrose eingesetzt. In ausgewählten Fällen ist eine Leberbiopsie notwendig, um den Grad der Fibrose und die Ätiologie der Lebererkrankung zu eruieren. Mithilfe eines Fallbeispiels, diskutieren die Autoren im Folgenden die rationale Anwendung diagnostischer Tests und deren korrekte Interpretation und schlagen eine Orientierungshilfe zur rationalen Abklärung von Patienten mit Lebererkrankungen vor.

Neue Horizonte bei der Lebersonographie

Praxis ◽  
2012 ◽  
Vol 101 (18) ◽  
pp. 1161-1166
Author(s):  
Hagara ◽  
Schwarzenbach ◽  
Cerny
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse

Dank technologischer Verbesserungen und einer immer besser werdenden klinischen Evidenzlage wird der diagnostische Ultraschall im Vergleich zu den Röntgen- und Magnetresonanzverfahren vermehrt eingesetzt. Dies nicht nur aus Kostengründen, sondern auch um der Zunahme der Strahlenbelastung der Bevölkerung durch diagnostische ionisierende Strahlen entgegenzuwirken. In der folgenden Übersichtsarbeit versuchen die Autoren die neuesten Entwicklungen im Bereich des Leberultraschalls vorzustellen. Bemerkenswert sind Verfahren, die eine dynamische Untersuchung der Leberdurchblutung mittels Kontrastmittelultraschall (Schwefelhexafluorid SonoVue®) und damit Verbesserungen bei der Charakterisierung von fokalen Leberläsionen wie Metastasen extrahepatischer Tumoren, Regeneratsknoten bei Leberzirrhose, fokaler nodulärer Hyperplasie, hepatozellu-lärem Karzinom, Leberhämangiom, Leberadenom sowie fokaler Mehr- oder Minderverfettung ermöglichen. Ebenfalls wichtig sind Techniken, die eine Bestimmung der Gewebekonsistenz mittels transienter Elastographie (Fibroscan), ARFI (Acoustic Radiation Force Impulse) oder Echtzeit-Gewebe-Elastographie erlauben. Die Quantifizierung des Steatosegrads ist für Diagnose und Verlaufsbeurteilung von Leberpathologien unabdingbar.

Acoustic Radiation Force Elastografie versus FibroScan zur nicht-invasive Beurteilung des Leberfibrosestadiums bei viraler Hepatitis

2009 ◽  
Vol 22 (01) ◽  
Author(s):  
M Friedrich-Rust ◽  
K Wunder ◽  
F Sotoudeh ◽  
S Kriener ◽  
S Martens ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force
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