Multidomain Modeling of Spatial Distributions of Tissue Optical Properties During Indentation: Mechanical Tissue Optical Clearing Devices as Diagnostic Tools

2011 ◽  
Author(s):  
William C. Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Soft Tissues ◽  
Light Transmission ◽  
Index Of Refraction ◽  
Diagnostic Tools ◽  
Infrared Range ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Soft tissues are highly heterogeneous materials comprised of water, proteins, and many types of cells. This composite configuration results in a large mismatch in index of refraction between tissue constituents, creating a high-scattering medium in the visible and near-infrared range. “Tissue optical clearing” can increase light transmission through these tissues, potentially improving both optical diagnostic and therapeutic procedures [1]. Dehydration has been shown to be a mechanism of optical clearing, and previous work has investigated mechanical loading as a method of creating reversible localized water displacement in skin using novel mechanical tissue optical clearing devices (TOCDs) [2]. In addition to potentially enhancing established light-based procedures, the principles of TOCD operation may provide a platform for a novel diagnostic tool capable of utilizing many different measurement types simultaneously.

Tissue Optical Clearing Devices: Effects of Water Content on the Hyperelastic Mechanical Properties of Ex Vivo Porcine Skin

2010 ◽  
Author(s):  
William Vogt ◽  
Alondra Izquierdo-Roman ◽  
Christopher G. Rylander
Keyword(s):  
Near Infrared ◽  
Light Transmission ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Complex Structure ◽  
Heterogeneous Material ◽  
Index Of Refraction ◽  
Water Displacement ◽  
Optical Clearing ◽  
Tissue Optical Clearing

Skin is a highly anisotropic and heterogeneous material composed of water, proteins, and various cells arranged in several different layers. Because of this complex structure, there is a large mismatch in index of refraction between the tissue constituents, creating a highly scattering medium for near-infrared and visible light. “Tissue optical clearing” methods can improve light transmission through tissues, potentially improving optical imaging techniques and photoirradiative treatments [1]. Dehydration has been suggested as a possible mechanism of optical clearing [2], and previous work has demonstrated mechanical loading as a method of creating reversible localized water displacement in skin using novel tissue optical clearing devices (TOCDs) [3–4]. These TOCDs were hypothesized to increase light transmission by displacing water locally in the tissue, causing local dehydration. A model of the mechanical behavior of skin will enable improvement of current TOCDs that utilize local mechanical compression.

Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin

2011 ◽  
Vol 43 (8) ◽  
pp. 814-823 ◽  
Author(s):  
Alondra Izquierdo-Román ◽  
William C. Vogt ◽  
Leeanna Hyacinth ◽  
Christopher G. Rylander
Keyword(s):  
Ex Vivo ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Clearing Technique ◽  
Imaging Resolution ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

Increased Light Transport in Skin Using Mechanical Compression

2009 ◽  
Author(s):  
Chris W. Drew ◽  
Alondra Izquierdo-Roman ◽  
Yajing Liu ◽  
Christopher G. Rylander
Keyword(s):  
Light Scattering ◽  
Structural Modification ◽  
Near Infrared ◽  
Morphological Structure ◽  
Light Transport ◽  
Optical Clearing ◽  
Treatment Techniques ◽  
Infrared Wavelengths ◽  
Tissue Optical Clearing ◽  
Highly Scattering Medium

The complex morphological structure of skin with its variations in the indices of refraction of components therein provides a highly scattering medium for visible and near-infrared wavelengths of light. “Tissue optical clearing” increases transmission of near-collimated light in biological tissue, potentially enabling improved optical analysis and treatment techniques. Numerous methods of tissue optical clearing have been hypothesized using hyperosmostic agents [1]. These methods propose reduction in light scattering by means of dehydration of tissue constituents, replacement of interstitial or intracellular water with higher refractive agents, or structural modification or dissociation of collagen fibers [2]. It has been suggested that dehydration of tissue constituents alone can reduce light scattering by expulsing water between collagen fibrils, increasing protein and sugar concentrations, and decreasing refractive index mismatch [3].

scholarly journals PARAMETRIC STUDY OF TISSUE OPTICAL CLEARING BY LOCALIZED MECHANICAL COMPRESSION USING COMBINED FINITE ELEMENT AND MONTE CARLO SIMULATION

2010 ◽  
Vol 03 (03) ◽  
pp. 203-211 ◽  
Author(s):  
WILLIAM C. VOGT ◽  
HAIOU SHEN ◽  
GE WANG ◽  
CHRISTOPHER G. RYLANDER
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Optical Properties ◽  
Light Transmission ◽  
Compressive Strain ◽  
Monte Carlo Model ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Tissue Optical Properties ◽  
Tissue Optical Clearing

Tissue Optical Clearing Devices (TOCDs) have been shown to increase light transmission through mechanically compressed regions of naturally turbid biological tissues. We hypothesize that zones of high compressive strain induced by TOCD pins produce localized water displacement and reversible changes in tissue optical properties. In this paper, we demonstrate a novel combined mechanical finite element model and optical Monte Carlo model which simulates TOCD pin compression of an ex vivo porcine skin sample and modified spatial photon fluence distributions within the tissue. Results of this simulation qualitatively suggest that light transmission through the skin can be significantly affected by changes in compressed tissue geometry as well as concurrent changes in tissue optical properties. The development of a comprehensive multi-domain model of TOCD application to tissues such as skin could ultimately be used as a framework for optimizing future design of TOCDs.

scholarly journals Mechanical tissue optical clearing devices: Enhancement of light penetration in ex vivo porcine skin and adipose tissue

2008 ◽  
Vol 40 (10) ◽  
pp. 688-694 ◽  
Author(s):  
Christopher G. Rylander ◽  
Thomas E. Milner ◽  
Stepan A. Baranov ◽  
J. Stuart Nelson
Keyword(s):  
Adipose Tissue ◽  
Ex Vivo ◽  
Light Penetration ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

scholarly journals Erratum: Mechanical tissue optical clearing technique increases imaging resolution and contrast through Ex vivo porcine skin

2011 ◽  
Vol 43 (10) ◽  
pp. 998-1007 ◽  
Author(s):  
Alondra Izquierdo-Román ◽  
William C. Vogt ◽  
Leeanna Hyacinth ◽  
Christopher G. Rylander
Keyword(s):  
Ex Vivo ◽  
Porcine Skin ◽  
Optical Clearing ◽  
Clearing Technique ◽  
Imaging Resolution ◽  
Tissue Optical Clearing ◽  
Mechanical Tissue

scholarly journals Investigating homeopathic preparations with light spectroscopy

2021 ◽  
Vol 11 (40) ◽  
pp. 117-117
Author(s):  
Ursula Wolf ◽  
Sabine Klein ◽  
Annegret Sandig ◽  
Stephan Baumgartner
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Light Transmission ◽  
Uv Light ◽  
Uv Spectroscopy ◽  
Visible Range ◽  
Infrared Range ◽  
Double Beam ◽  
Uv Range

Background Several series of experiments from our research group have shown ultraviolet (UV) light transmission of homeopathic preparations to slightly but significantly differ from controls. We now investigated whether visible and near infrared spectroscopy were also useful for exploring properties of homeopathic preparations. Materials and methods Homeopathic preparations of copper sulfate (CuSO4), hypericum and sulfur (S8) were produced in 30 sequential steps of 1:100 dilutions (c-preparations). As controls, succussed potentization medium was used. Transmission of the samples from 190-1100nm was measured 4 times on 5 days with a double beam Shimadzu UV PC 1601 spectrophotometer. To correct for the daily variations of the spectrophotometer, transmission of the samples at each nm was divided by the average transmission of the controls. Median transmissions of the samples were calculated for the ranges of 190-340nm (near and middle UV), 340-640nm (visible light without red), and 640-1100nm (red and near infrared). Differences in the median transmission between potency levels from 6c to 30c were determined using Kruskal-Wallis and Jonckheere-Terpstra tests. Results Differences in transmissions of the various potency levels were more pronounced in the UV range than in the visible or red/near infrared range. The Kruskal-Wallis test revealed significant differences for homeopathic preparations of CuSO4, hypericum and S8 in the UV range (p=0.032, 0.008, 0.009, respectively) and of S8 in the visible range (p=0.026). Jonckheere's test showed a tendency towards ascending medians with ascending potency levels for CuSO4 in the UV range (p=0.080). Significant trends were revealed for hypericum in the visible range (p=0.042, descending medians) and S8 in the UV range (p=0.015, ascending medians). Conclusion UV spectroscopy seemed to be more suitable for investigating homeopathic preparations than visible or near infrared spectroscopy, since differences in transmission were more pronounced in the UV range.

Infrared and Visible—Near Infrared Electroluminescence Developments for FA in AlGaN/GaN HEMTS on SiC

2010 ◽  
Author(s):  
M. Bouya ◽  
D. Carisetti ◽  
J.C. Clement ◽  
N. Malbert ◽  
N. Labat ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Near Infrared ◽  
High Electron Mobility Transistor ◽  
Low Noise ◽  
Civil Defense ◽  
Base Stations ◽  
Infrared Range ◽  
High Electron ◽  
Radar Applications ◽  
Gan Hemts

Abstract HEMT (High Electron Mobility Transistor) are playing a key role for power and RF low noise applications. They are crucial components for the development of base stations in the telecommunications networks and for civil, defense and space radar applications. As well as the improvement of the MMIC performances, the localization of the defects and the failure analysis of these devices are very challenging. To face these challenges, we have developed a complete approach, without degrading the component, based on front side failure analysis by standard (Visible-NIR) and Infrared (range of wavelength: 3-5 µm) electroluminescence techniques. Its complementarities and efficiency have been demonstrated through two case studies.

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