Accurate Technique for Measuring Electrical Permittivity of Biological Tissues at Low Frequencies and Sensitivity Analysis

2018 ◽  
Author(s):  
Seyyed M. Hesabgar ◽  
Reza Jafari ◽  
Abbas Samani
Keyword(s):  
Sensitivity Analysis ◽  
Biological Tissues ◽  
Low Frequencies ◽  
Electrical Permittivity

scholarly journals Sensitivity analysis of non‐local damage in soft biological tissues

2020 ◽  
Author(s):  
Di Zuo ◽  
Stéphane Avril ◽  
Chunjiang Ran ◽  
Haitian Yang ◽  
S. Jamaleddin Mousavi ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Biological Tissues ◽  
Local Damage ◽  
Soft Biological Tissues ◽  
Non Local

scholarly journals Imaging biological tissues by utilizing ultrasound and electromagnetic fields

2021 ◽  
Author(s):  
Elena Renzhiglova
Keyword(s):  
Magnetic Moment ◽  
Relative Permittivity ◽  
Radiation Force ◽  
Biological Tissues ◽  
Ultrasound Wave ◽  
Electrical Tomography ◽  
Electrical Field ◽  
Impedance Modulation ◽  
Muscle Tissues ◽  
Electrical Permittivity

This thesis reports our research on developing a new method to image the electric conductivity and relative permittivity of biological tissues. The first method is Differential Frequency Magneto-Acousto-Electrical Tomography (DF-MAET) to image the electrical impedance of biological tissues with high spatial resolution. It is shown that DF-MAET signal is caused by the vibrations of the sample at a difference frequency (DF) because of the radiation force. In the second method, we investigated the possibility of using a novel mechanism for imaging the electrical permittivity of biological tissues. Theoretical study shows that a magnetic moment will be produced in biological tissues when both and ultrasound wave and an electrical field exist in the tissue. We report the results to detect this magnetic moment with both coils and electrodes attached to the tissue. We were able to detect the signal with electrodes, but its frequency dependence indicates that this signal is due to the impedance modulation by ultrasound, and that it is not related to the relative permittivity. Finally, we studied the ultrasonic vibration potentials generated in fat and muscle tissues.

scholarly journals Dirac cones and chiral selection of elastic waves in a soft strip

2020 ◽  
Vol 117 (48) ◽  
pp. 30186-30190
Author(s):  
Maxime Lanoy ◽  
Fabrice Lemoult ◽  
Antonin Eddi ◽  
Claire Prada
Keyword(s):  
Elastic Waves ◽  
Soft Materials ◽  
Biological Tissues ◽  
Dirichlet Boundary Conditions ◽  
Thin Strip ◽  
Negative Wave ◽  
Low Frequencies ◽  
Chiral Selection ◽  
Zero Group ◽  
Wave Phenomena

We study the propagation of in-plane elastic waves in a soft thin strip, a specific geometrical and mechanical hybrid framework which we expect to exhibit a Dirac-like cone. We separate the low frequencies guided modes (typically 100 Hz for a 1-cm-wide strip) and obtain experimentally the full dispersion diagram. Dirac cones are evidenced together with other remarkable wave phenomena such as negative wave velocity or pseudo-zero group velocity (ZGV). Our measurements are convincingly supported by a model (and numerical simulation) for both Neumann and Dirichlet boundary conditions. Finally, we perform one-way chiral selection by carefully setting the source position and polarization. Therefore, we show that soft materials support atypical wave-based phenomena, which is all of the more interesting as they make most of the biological tissues.

Three-Dimensional Visualization of the T-System of Frog Muscle Using High Voltage Electron Microscopy and a Lanthanum Stain

1977 ◽  
Vol 35 ◽  
pp. 570-571 ◽  
Author(s):  
Lee D. Peachey ◽  
Clara Franzini-Armstrong
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Three Dimensional ◽  
Biological Tissues ◽  
High Voltage Electron Microscopy ◽  
Transverse Tubular System ◽  
Peroxidase Reaction ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
T System

The effective study of biological tissues in thick slices of embedded material by high voltage electron microscopy (HVEM) requires highly selective staining of those structures to be visualized so that they are not hidden or obscured by other structures in the image. A tilt pair of micrographs with subsequent stereoscopic viewing can be an important aid in three-dimensional visualization of these images, once an appropriate stain has been found. The peroxidase reaction has been used for this purpose in visualizing the T-system (transverse tubular system) of frog skeletal muscle by HVEM (1). We have found infiltration with lanthanum hydroxide to be particularly useful for three-dimensional visualization of certain aspects of the structure of the T- system in skeletal muscles of the frog. Specifically, lanthanum more completely fills the lumen of the tubules and is denser than the peroxidase reaction product.

On the High Voltage Electron Microscopy (1 MeV) of Biological Thick Sections

1972 ◽  
Vol 30 ◽  
pp. 464-465
Author(s):  
William H. Massover
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Present Report ◽  
Biological Tissues ◽  
Specimen Preparation ◽  
Technical Problems ◽  
High Voltage Electron Microscopy ◽  
Thin Sections ◽  
Voltage Electron ◽  
High Voltage Electron

Stereoscopic examination of thick sections of fixed and embedded biological tissues by high voltage electron microscopy has been shown to allow direct visualization of three-dimensional fine structure. The present report will consider the occurrence of some new technical problems in specimen preparation and Image interpretation that are not common during lower voltage studies of thin sections.Thick Sectioning and Tissue Coloration - Epon sections of 0.5 μm or more that are cut with glass knives do not have a uniform thickness as Judged by their interference colors; these colors change with time during their flotation on the knife bath, and again when drying onto the specimen support. Quoted thicknesses thus must be considered only as rough estimates unless measured in specific regions by other methods. Chloroform vapors do not always result in good spreading of thick sections; however, they will spread spontaneously to large degrees after resting on the flotation bath for several minutes. Ribbons of thick sections have been almost impossible to obtain.

Rapid Critical Point Drying of Tissues in a Parr Bomb

1972 ◽  
Vol 30 ◽  
pp. 400-401
Author(s):  
C.A. Baechler ◽  
W. C. Pitchford ◽  
J. M. Riddle ◽  
C.B. Boyd ◽  
H. Kanagawa ◽  
...  
Keyword(s):  
Critical Point ◽  
Critical Pressure ◽  
Soft Tissues ◽  
Biological Tissues ◽  
Critical Temperatures ◽  
Air Drying ◽  
The Past ◽  
Critical Point Drying ◽  
Great Stress ◽  
Infiltration Techniques

Preservation of the topographic ultrastructure of soft biological tissues for examination by scanning electron microscopy has been accomplished in the past by using lengthy epoxy infiltration techniques, or dehydration in ethanol or acetone followed by air drying. Since the former technique requires several days of preparation and the latter technique subjects the tissues to great stress during the phase change encountered during air-drying, an alternate rapid, economical, and reliable method of surface structure preservation was developed. Turnbill and Philpott had used a fluorocarbon for the critical point drying of soft tissues and indicated the advantages of working with fluids having both moderately low critical pressures as well as low critical temperatures. Freon-116 (duPont) which has a critical temperature of 19. 7 C and a critical pressure of 432 psi was used in this study.

Applications of Time-OF-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

1990 ◽  
Vol 48 (2) ◽  
pp. 308-309
Author(s):  
Bruno Schueler ◽  
Robert W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Information ◽  
Time Of Flight ◽  
Biological Tissues ◽  
Polymer Surfaces ◽  
Tof Sims ◽  
Secondary Ions ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides unique capabilities for elemental and molecular compositional analysis of a wide variety of surfaces. This relatively new technique is finding increasing applications in analyses concerned with determining the chemical composition of various polymer surfaces, identifying the composition of organic and inorganic residues on surfaces and the localization of molecular or structurally significant secondary ions signals from biological tissues. TOF-SIMS analyses are typically performed under low primary ion dose (static SIMS) conditions and hence the secondary ions formed often contain significant structural information.This paper will present an overview of current TOF-SIMS instrumentation with particular emphasis on the stigmatic imaging ion microscope developed in the authors’ laboratory. This discussion will be followed by a presentation of several useful applications of the technique for the characterization of polymer surfaces and biological tissues specimens. Particular attention in these applications will focus on how the analytical problem impacts the performance requirements of the mass spectrometer and vice-versa.

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