Measurement of Acoustic Emission Wave Attenuation by Bones and Muscles

2007 ◽  
Author(s):  
Benjamin Pruden ◽  
Ozan Akkus
Keyword(s):  
Acoustic Emission ◽  
Wave Attenuation ◽  
Physiological Activity ◽  
Acoustic Emissions ◽  
Biological Tissues ◽  
The Body ◽  
Frequency Range ◽  
Mode Separation ◽  
Viscous Losses

Stress fractures occur in bones of athletes and soldiers due to the accumulation of microcracks [1]. Detection of precursor acoustic emissions (i.e. ultrasonic stress waves) resulting from microcrack activity may help predict failure onset before continuous physiological activity results in full-blown fracture. An acoustic emission wave generated from a microcrack in bone will be diminished by dispersion, mode separation, reflection, and viscous losses induced by the biological tissues (skin, muscle, fat) between the source and the transducer. While others have recorded waves emanating from unknown loci in human knee in vivo using acoustic emission method [2], there is no means to appreciate how far these waves can travel in the body. Several studies have characterized the ultrasound attenuation in bone [3] and muscle analog homogenates [4] in the frequency range above 300 kHz. On the other hand, acoustic emissions are prominent in the range of 20 kHz to 300 kHz. The current study focused on identifying the attenuation of acoustic emission waves in bone and muscle tissues in a frequency range which is more relevant to acoustic emissions. This information is critical for predicting whether an emission of certain magnitude at the source can reach surface mounted sensors without being totally attenuated.

scholarly journals Acoustic Emission in Snow at Constant Rates of Deformation

1973 ◽  
Vol 12 (64) ◽  
pp. 144-146 ◽  
Author(s):  
W. F. St. Lawrence ◽  
T. E. Lang ◽  
R.L. Brown ◽  
C. C. Bradley
Keyword(s):  
Acoustic Emission ◽  
Brittle Fracture ◽  
Uniaxial Compression ◽  
Laboratory Experiments ◽  
Acoustic Emissions ◽  
Snow Sample ◽  
Frequency Range ◽  
Snow Samples

AbstractAcoustic emissions in the audio spectrum are reported from observations of laboratory experiments conducted on snow samples in uniaxial compression. A number of tests show the pattern of acoustic emissions to be a function of the rate of deformation. Over the frequency range 20 to 7 000 Hz acoustic emissions are associated with rates of deformation corresponding to brittle fracture of the snow sample. Though probably present, no acoustic emissions were detected from samples deforming plastically.

scholarly journals Frictional internal work of damped limbs oscillation in human locomotion

2020 ◽  
Vol 287 (1931) ◽  
pp. 20201410 ◽  
Author(s):  
Alberto E. Minetti ◽  
Alex P. Moorhead ◽  
Gaspare Pavei
Keyword(s):  
Energy Balance ◽  
Time Course ◽  
Ex Vivo ◽  
Biological Tissues ◽  
The Body ◽  
Lower Limbs ◽  
Metabolic Energy ◽  
External Work ◽  
Internal Work

Joint friction has never previously been considered in the computation of mechanical and metabolic energy balance of human and animal (loco)motion, which heretofore included just muscle work to move the body centre of mass (external work) and body segments with respect to it. This happened mainly because, having been previously measured ex vivo , friction was considered to be almost negligible. Present evidences of in vivo damping of limb oscillations, motion captured and processed by a suited mathematical model, show that: (a) the time course is exponential, suggesting a viscous friction operated by the all biological tissues involved; (b) during the swing phase, upper limbs report a friction close to one-sixth of the lower limbs; (c) when lower limbs are loaded, in an upside-down body posture allowing to investigate the hip joint subjected to compressive forces as during the stance phase, friction is much higher and load dependent; and (d) the friction of the four limbs during locomotion leads to an additional internal work that is a remarkable fraction of the mechanical external work. These unprecedented results redefine the partitioning of the energy balance of locomotion, the internal work components, muscle and transmission efficiency, and potentially readjust the mechanical paradigm of the different gaits.

scholarly journals Acoustic Emission in Snow at Constant Rates of Deformation

1973 ◽  
Vol 12 (64) ◽  
pp. 144-146 ◽  
Author(s):  
W. F. St. Lawrence ◽  
T. E. Lang ◽  
R.L. Brown ◽  
C. C. Bradley
Keyword(s):  
Acoustic Emission ◽  
Brittle Fracture ◽  
Uniaxial Compression ◽  
Laboratory Experiments ◽  
Acoustic Emissions ◽  
Snow Sample ◽  
Frequency Range ◽  
Snow Samples

Abstract Acoustic emissions in the audio spectrum are reported from observations of laboratory experiments conducted on snow samples in uniaxial compression. A number of tests show the pattern of acoustic emissions to be a function of the rate of deformation. Over the frequency range 20 to 7 000 Hz acoustic emissions are associated with rates of deformation corresponding to brittle fracture of the snow sample. Though probably present, no acoustic emissions were detected from samples deforming plastically.

A Comparison of Magnetometry and Relaxometry Measures of Magnetic Nanoparticles Deposited in Biological Samples

2015 ◽  
Vol 31 ◽  
pp. 129-137 ◽  
Author(s):  
Ana Lorena Urbano-Bojorge ◽  
Nazario Félix-González ◽  
Tamara Fernández ◽  
Francisco del Pozo-Guerrero ◽  
Milagros Ramos ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Nanostructures ◽  
High Sensitivity ◽  
Biological Tissues ◽  
The Body ◽  
In Vivo Studies ◽  
Gradient Field ◽  
Measurement Protocol

The Alternating Gradient Field Magnetometer (AGFM) is an instrument whose high sensitivity (10-8 emu) allows the detection of small amounts of magnetic nanoparticles (MNPs) with high accuracy. Over the last few years, different magnetic techniques have been used for in vitro measurements of magnetic nanostructures inside biological tissues. However, in vivo studies about their distribution within the body are very scarce because their dispersion, after being delivered, reduces their magnetic signal and hinders detection. In this paper we compare the longitudinal relaxation time (T1) and magnetization measurements in mice's biological tissues for the tracking of MNPs after of an injection of iron oxide nanoparticles. Furthermore, we have correlated the AGFM data with Fast Field Cycling NMR Relaxometry (FFCNMR Relaxometry) measurements with histological analysis. The results have demonstrated that these techniques are useful for detecting minute amounts of MNPs in excised organs after in-vivo comparable to other more conventional techniques for the measurement of MNPs biodistribution and clearance. Details about the preparation of the in vivo samples, measurement protocol and statistical data processing are given.

Effect of highly porous bioceramics based on ZrO2 – Y2O3 – CeO2 system on the biological tissues of experimental animals

2020 ◽  
pp. 29-39
Author(s):  
M. V. Kalinina ◽  
◽  
N. Yu. Kovalko ◽  
D. N. Suslov ◽  
Yu. S. Andozhskaia ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Pore Space ◽  
Biological Tissues ◽  
The Body ◽  
Laboratory Animals ◽  
Experimental Animals ◽  
Average Grain Size ◽  
Porous Bioceramics ◽  
Highly Porous

By reverse co-deposition of hydroxides synthesized highly dispersed powder (the average size 8 – 10 nm) of the composition (ZrO2)0.92(Y2О3)0.03(СеО2)0.05, based on it use comprehensive a blowing agent and mechanical activation of the obtained highly porous ceramics (average grain size 60 – 65 nm). The synthesized ceramic material-an implant with an open porosity of 55 % and a pore size of 40 – 800 nm was placed in the body of laboratory animals. The reaction of biological tissues of experimental animals to the introduction of plates made of composite highly porous materials based on t-ZrO2 15 months after their implantation was studied. It is revealed that enhanced revascularization is registered in capsules, and perfusion of tissues is registered in intact zone of ceramics introduction. The possibility of germination of vessels in soft tissues into the available pore space of ceramics is shown. The results obtained in vivo suggest that porous bioceramics based on t-ZrO2 can be used in the production of endoprostheses and implants in such areas of medicine as orthopedics and traumatology.

scholarly journals Synthesis and Characterization of GdVO4:Nd Near-Infrared Phosphors for Optical Time-Gated In Vivo Imaging

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3564
Author(s):  
Ben Nimmegeers ◽  
Ewoud Cosaert ◽  
Tecla Carbonati ◽  
Daniela Meroni ◽  
Dirk Poelman
Keyword(s):  
Decay Time ◽  
Near Infrared ◽  
Imaging Techniques ◽  
Medical Personnel ◽  
Biological Tissues ◽  
The Body ◽  
Transparency Window ◽  
Optical Time ◽  
Gated Imaging

Many medical imaging techniques use some form of ionizing radiation. This radiation is not only potentially harmful for the patient, but also for the medical personnel. An alternative imaging technique uses near-infrared (NIR) emitting luminescent particles as tracers. If the luminescent probes are excited inside the body, autofluorescence from the biological tissues is also induced. This problem can be circumvented by using time-gated imaging. Hereby, the light collection only starts when the fluorescence of the tissue has decayed. This requires particles showing both excitation and emission in the near-infrared and a long decay time so that they can be used in time-gated imaging. In this work, Nd-doped GdVO4 NIR emitting particles were prepared using solid state reaction. Particles could be efficiently excited at 808 nm, right in the first transparency window for biological tissues, emitted in the second transparency window at around 1064 nm, and showed a decay time of the order of 70 μs, sufficiently long for time-gating. By using a Gd-containing host, these particles could be ideally suited for multimodal optical/magnetic imaging after size reduction and surface functionalization.

scholarly journals iRFP (near-infrared fluorescent protein) imaging of subcutaneous and deep tissue tumours in mice highlights differences between imaging platforms

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
C. Hall ◽  
Y. von Grabowiecki ◽  
S. P. Pearce ◽  
C. Dive ◽  
S. Bagley ◽  
...  
Keyword(s):  
Cancer Biology ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Dynamic Range ◽  
Fluorescent Proteins ◽  
Biological Tissues ◽  
The Body ◽  
Nsg Mice ◽  
Infrared Fluorescent Protein

Abstract Background In vivo imaging using fluorescence is used in cancer biology for the detection, measurement and monitoring of tumours. This can be achieved with the expression of fluorescent proteins such as iRFP, which emits light at a wavelength less attenuated in biological tissues compared to light emitted by other fluorescent proteins such as GFP or RFP. Imaging platforms capable of detecting fluorescent tumours in small animals have been developed but studies comparing the performance of these platforms are scarce. Results Through access to three platforms from Xenogen, Bruker and Li-Cor, we compared their ability to detect iRFP-expressing subcutaneous tumours as well as tumours localised deeper within the body of female NSG mice. Each platform was paired with proprietary software for image analyse, but the output depends on subjective decisions from the user. To more objectively compare platforms, we developed an ‘in house’ software-based approach which results in lower measured variability between mice. Conclusions Our comparisons showed that all three platforms allowed for reliable detection and monitoring of subcutaneous iRFP tumour growth. The biggest differences between platforms became apparent when imaging deeper tumours with the Li-Cor platform detecting most tumours and showing the highest dynamic range.

scholarly journals Fully Implanted Prostheses for Musculoskeletal Limb Reconstruction after Amputation: An In Vivo Feasibility Study

2020 ◽  
Author(s):  
Patrick T. Hall ◽  
Samantha Z. Bratcher ◽  
Caleb Stubbs ◽  
Rebecca E. Rifkin ◽  
Remi M. Grzeskowiak ◽  
...  
Keyword(s):  
Rabbit Model ◽  
Surgical Care ◽  
Biological Tissues ◽  
Medullary Canal ◽  
The Body ◽  
Surgical Incision ◽  
New Zealand White Rabbits ◽  
Future Work ◽  
Limb Prosthesis

AbstractPrevious prostheses for replacing a missing limb following amputation must be worn externally on the body. This limits the extent to which prostheses could physically interface with biological tissues, such as muscles, to enhance functional recovery. The objectives of our study were to (1) test the feasibility of implanting a limb prosthesis, or endoprosthesis, entirely within living skin at the distal end of a residual limb, and (2) identify effective surgical and post-surgical care approaches for implanting endoprostheses in a rabbit model of hindlimb amputation. We iteratively designed, fabricated, and implanted unjointed endoprosthesis prototypes in six New Zealand White rabbits following amputation. In the first three rabbits, the skin failed to heal due to dehiscence along the sutured incision. The skin of the final three subsequent rabbits successfully healed over the endoprotheses. Factors that contributed to successful outcomes included modifying the surgical incision to preserve vasculature; increasing the radii size on the endoprostheses to reduce skin stress; collecting radiographs pre-surgery to match the bone pin size to the medullary canal size; and ensuring post-operative bandage integrity. These results will support future work to test jointed endoprostheses that can be attached to muscles.

scholarly journals Electrical characterization of bolus material as phantom for use in electrical impedance and computed tomography fusion imaging

2019 ◽  
Vol 5 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Parvind K Grewal ◽  
Majid Shokoufi ◽  
Jeff Liu ◽  
Krishnan Kalpagam ◽  
Kirpal S Kohli
Keyword(s):  
Electrical Impedance ◽  
Electrical Characterization ◽  
Fusion Imaging ◽  
Biological Tissues ◽  
Frequency Range ◽  
Imaging Studies ◽  
Impedance Tomography ◽  
Clinical Imaging

Abstract Phantoms are widely used in medical imaging to predict image quality prior to clinical imaging. This paper discusses the possible use of bolus material, as a conductivity phantom, for validation and interpretation of electrical impedance tomography (EIT) images. Bolus is commonly used in radiation therapy to mimic tissue. When irradiated, it has radiological characteristics similar to tissue. With increased research interest in CT/EIT fusion imaging there is a need to find a material which has both the absorption coefficient and electrical conductivity similar to biological tissues. In the present study the electrical properties, specifically resistivity, of various commercially available bolus materials were characterized by comparing their frequency response with that of in-vivo connective adipose tissue. It was determined that the resistivity of Gelatin Bolus is similar to in-vivo tissue in the frequency range 10 kHz to 1MHz and therefore has potential to be used in EIT/CT fusion imaging studies.

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