Absorption and Scatter Corrections for Transflectance Measurements in Nonhomogeneous Fiber Samples

1998 ◽  
Vol 6 (A) ◽  
pp. A35-A44 ◽  
Author(s):  
R.A. Taylor
Keyword(s):  
High Speed ◽  
Near Infrared ◽  
Light Transmission ◽  
Accurate Determination ◽  
Fiber Optic Sensor ◽  
Infrared Light ◽  
Specimen Preparation ◽  
Absorption Bands ◽  
Speed Sensor ◽  
Wide Range

A new fiber optic sensor was developed to measure the mass of optically thin cotton samples by integrating light transmission and reflectance signals. High speed measurements of cotton strength requires an accurate determination of the specimen mass without use of laborious cut-and-weigh methods. A previous high speed sensor measured changes in visible light transmission which required secondary measurements of fiber fineness to adjust the data for light scattering. Fiber orientation also affected scattering which required a precise control on specimen preparation. The new sensor measures fiber specimen transflectance using near infrared light. Because cellulose (the basic compound in cotton) exhibits strong absorption bands, its concentration can be accurately measured using near infrared absorbance. In this report we show that an integratinq sensor gave the best measurement of cotton fiber mass. Additionally, we demonstrated its accuracy over a wide range of fiber orientations using a novel fiber specimen tension experiment.

scholarly journals The Various Oximetric Techniques Used for the Evaluation of Blood Oxygenation

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4844
Author(s):  
Meir Nitzan ◽  
Itamar Nitzan ◽  
Yoel Arieli
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Near Infrared ◽  
Light Transmission ◽  
Venous Blood ◽  
Blood Oxygenation ◽  
Infrared Light ◽  
Cerebral Tissue ◽  
Peripheral Muscle ◽  
Arterial Blood

Adequate oxygen delivery to a tissue depends on sufficient oxygen content in arterial blood and blood flow to the tissue. Oximetry is a technique for the assessment of blood oxygenation by measurements of light transmission through the blood, which is based on the different absorption spectra of oxygenated and deoxygenated hemoglobin. Oxygen saturation in arterial blood provides information on the adequacy of respiration and is routinely measured in clinical settings, utilizing pulse oximetry. Oxygen saturation, in venous blood (SvO2) and in the entire blood in a tissue (StO2), is related to the blood supply to the tissue, and several oximetric techniques have been developed for their assessment. SvO2 can be measured non-invasively in the fingers, making use of modified pulse oximetry, and in the retina, using the modified Beer–Lambert Law. StO2 is measured in peripheral muscle and cerebral tissue by means of various modes of near infrared spectroscopy (NIRS), utilizing the relative transparency of infrared light in muscle and cerebral tissue. The primary problem of oximetry is the discrimination between absorption by hemoglobin and scattering by tissue elements in the attenuation measurement, and the various techniques developed for isolating the absorption effect are presented in the current review, with their limitations.

Indium Antimonide (InSb) Focal Plane Array (FPA) Detection for Near-Infrared Imaging Microscopy

1994 ◽  
Vol 48 (5) ◽  
pp. 607-615 ◽  
Author(s):  
Patrick J. Treado ◽  
Ira W. Levin ◽  
E. Neil Lewis
Keyword(s):  
Indium Antimonide ◽  
High Speed ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Optical Microscope ◽  
Tunable Filter ◽  
Model Systems ◽  
High Spectral Resolution ◽  
Spectral Interval ◽  
Wide Range

Near-infrared spectroscopy is a sensitive, noninvasive method for chemical analyses, and its integration with imaging technologies represents a potent tool for the study of a wide range of materials. In this communication the use of an indium antimonide (InSb) multichannel imaging detector for near-infrared absorption spectroscopic microscopy is described. In particular, a 128 × 128 pixel InSb staring array camera has been combined with a refractive optical microscope and an acousto-optic tunable filter (AOTF) to display chemically discriminative, spatially resolved, vibrational spectroscopic images of biological and polymeric systems. AOTFs are computer-controlled bandpass filters that provide high speed, random wavelength access, wide spectral coverage, and high spectral resolution. Although AOTFs inherently have a wide range of spectroscopic applications, we apply this technology to NIR absorption microscopy between 1 and 2.5 μm. The spectral interval is well matched to the optical characteristics of both the NIR refractive microscope and the AOTF, thereby providing near-diffraction-limited performance with a practical spatial resolution of 1 to 2 μm. Design principles of this novel instrumentation and representative applications of the technique are presented for various model systems.

scholarly journals Age-related changes in diffuse optical tomography sensitivity profiles in infancy

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252036
Author(s):  
Xiaoxue Fu ◽  
John E. Richards
Keyword(s):  
Near Infrared ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Hemoglobin Concentration ◽  
Separation Distance ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Photon Propagation ◽  
Age Related ◽  
Wide Range

Diffuse optical tomography uses near-infrared light spectroscopy to measure changes in cerebral hemoglobin concentration. Anatomical interpretations of the location that generates the hemodynamic signal requires accurate descriptions of diffuse optical tomography sensitivity to the underlying cortical structures. Such information is limited for pediatric populations because they undergo rapid head and brain development. The present study used photon propagation simulation methods to examine diffuse optical tomography sensitivity profiles in realistic head models among infants ranging from 2 weeks to 24 months with narrow age bins, children (4 and 12 years) and adults (20 to 24 years). The sensitivity profiles changed systematically with the source-detector separation distance. The peak of the sensitivity function in the head was largest at the smallest separation distance and decreased as separation distance increased. The fluence value dissipated more quickly with sampling depth at the shorter source-detector separations than the longer separation distances. There were age-related differences in the shape and variance of sensitivity profiles across a wide range of source-detector separation distances. Our findings have important implications in the design of sensor placement and diffuse optical tomography image reconstruction in (functional) near-infrared light spectroscopy research. Age-appropriate realistic head models should be used to provide anatomical guidance for standalone near-infrared light spectroscopy data in infants.

Near-infrared spectrophotometric device to measure fluid exchange in blood-perfused organs

1993 ◽  
Vol 74 (5) ◽  
pp. 2205-2213 ◽  
Author(s):  
L. Oppenheimer ◽  
D. Huebert
Keyword(s):  
Linear Correlation ◽  
Near Infrared ◽  
Light Transmission ◽  
Excellent Correlation ◽  
Free Hemoglobin ◽  
Fluid Exchange ◽  
Wide Range ◽  
On Line

We describe an on-line spectrophotometric device designed to estimate the volume of transvascular fluid exchange (VE) continuously in isolated organ preparations. The device is interposed in the perfusion circuit, and VE is continuously estimated from changes in light transmission proportional to changes in perfusate hematocrit. In our perfusing circuit, hemolysis was negligible. Using hourly determinations of free hemoglobin, we estimated errors in VE due to hemolysis to be on the order of 1 ml for every hour of perfusion (expt I). When logarithms of on-line spectrophotometric signals were plotted against measured hematocrits (expt II), there was always an excellent linear correlation over a wide range of hematocrits (from 0.247 to 0.583). Finally, there was also an excellent correlation between spectrophotometric [QF(Spectr)] and gravimetric [QF(wt)] estimates of constant rates of transvascular fluid exchange in five isolated excised canine left lower pulmonary lobes, where QF(Spectr) = delta VE/delta t and QF(wt) = delta wt/delta t (expt III). QF(Spectr) = 1.035QF(wt) - 0.038 (r2 = 0.9772).

scholarly journals Photothermal Polymer Nanocomposites of Tungsten Bronze Nanorods with Enhanced Tensile Elongation at Low Filler Contents

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1740 ◽  
Author(s):  
Byoungyun Jeon ◽  
Taehyung Kim ◽  
Dabin Lee ◽  
Tae Joo Shin ◽  
Kyung Wha Oh ◽  
...  
Keyword(s):  
Polymer Nanocomposites ◽  
Near Infrared ◽  
Tensile Elongation ◽  
Tungsten Bronze ◽  
Heat Emission ◽  
Cold Weather ◽  
Infrared Light ◽  
Droplet Transport ◽  
Wide Range ◽  
Weather Resistance

We present polymer nanocomposites of tungsten bronze nanorods (TBNRs) and ethylene propylene diene monomers (EPDM). The combination of these components allows the simultaneous enhancement in the mechanical and photothermal properties of the composites at low filler contents. The as-synthesized TBNRs had lengths and diameters of 14.0 ± 2.4 nm and 2.5 ± 0.5 nm, respectively, and were capped with oleylamine, which has a chemical structure similar to EPDM, making the TBNRs compatible with the bulk EPDM matrix. The TBNRs absorb a wide range of near-infrared light because of the sub-band transitions induced by alkali metal doping. Thus, the nanocomposites of TBNRs in EPDM showed enhanced photothermal properties owing to the light absorption and subsequent heat emission by the TBNRs. Noticeably, the nanocomposite with only 3 wt% TBNRs presented significantly enhanced tensile strain at break, in comparison with those of pristine EPDM, nanocomposites with 1 and 2 wt % TBNRs, and those with tungsten bronze nanoparticles, because of the alignment of the nanorods during tensile elongation. The photothermal and mechanical properties of these nanocomposites make them promising materials for various applications such as in fibers, foams, clothes with cold weather resistance, patches or mask-like films for efficient transdermal delivery upon heat generation, and photoresponsive surfaces for droplet transport by the thermocapillary effect in microfluidic devices and microengines.

scholarly journals Biomedical optical properties of color light and near-infrared fluorescence separated-merged imager

2019 ◽  
Vol 12 (06) ◽  
pp. 1940001
Author(s):  
Rui Zhang ◽  
Ya-Zhou Xue ◽  
Xiao-Feng Yang
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Perioperative Period ◽  
Infrared Light ◽  
Agarose Gel ◽  
Near Infrared Fluorescence ◽  
Imaging Characteristics ◽  
Reflected Light ◽  
Wide Range

Objective: We study the biomedical optical properties of the color light and near-infrared fluorescence separated-merged imager. Materials and Methods: The color light and near-infrared fluorescence separated-merged imager can illuminate the visible light and the near-infrared light of [Formula: see text][Formula: see text]nm, receiving the reflected light and [Formula: see text][Formula: see text]nm near-infrared fluorescence, and display the color, fluorescence and merge image. ICG solution of different concentration, including standing time, was allocated to study the best imaging condition in vitro, and the depth of fluorescence penetration was studied with 5% agarose gel; the imaging characteristics of the imager was studied using SD rat; and then the SLNs tracing in 4 cases of penile carcinoma was performed. Results: When the concentration of ICG is 13.11[Formula: see text][Formula: see text]mol/L, the fluorescence intensity and the merge image are the best. The maximum depth of fluorescence imaging is 9[Formula: see text]mm in 5% agarose gel, while the bone has the greatest influence on it. The SLNs tracing shows that the imager can locate the SLNs in vitro, to achieve perioperative navigation during biopsy. Conclusion: There are many factors that affect the imaging effect, but the imaging effect of the imager meets the requirement of vision in a wide range, and can effectively trace the SLNs in perioperative period.

scholarly journals Lipophilicity of Bacteriochlorin-Based Photosensitizers as a Determinant for PDT Optimization through the Modulation of the Inflammatory Mediators

2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Barbara Pucelik ◽  
Luis G. Arnaut ◽  
Janusz M. Dąbrowski
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Near Infrared ◽  
Antitumor Immune Response ◽  
Infrared Light ◽  
Gm Csf ◽  
Hydrophobic Compound ◽  
Tnf Α ◽  
Wide Range

Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2.

scholarly journals Transcranial Red and Near Infrared Light Transmission in a Cadaveric Model

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47460 ◽  
Author(s):  
Jared R. Jagdeo ◽  
Lauren E. Adams ◽  
Neil I. Brody ◽  
Daniel M. Siegel
Keyword(s):  
Near Infrared ◽  
Light Transmission ◽  
Infrared Light ◽  
Near Infrared Light ◽  
Cadaveric Model
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