1. Articles from Felix I. Feldchtein

    1-21 of 21
    1. Quantitative evaluation of atherosclerotic plaques using cross-polarization optical coherence tomography, nonlinear, and atomic force microscopy

      Quantitative evaluation of atherosclerotic plaques using cross-polarization optical coherence tomography, nonlinear, and atomic force microscopy

      A combination of approaches to the image analysis in cross-polarization optical coherence tomography (CP OCT) and high-resolution imaging by nonlinear microscopy and atomic force microscopy (AFM) at the different stages of atherosclerotic plaque development is studied. This combination allowed us to qualitatively and quantitatively assess the disorganization of collagen in the atherosclerotic arterial tissue (reduction and increase of CP backscatter), at the fiber (change of the geometric distribution of fibers in the second-harmonic generation microscopy images) and fibrillar (violation of packing and different nature of a basket-weave network of fibrils in the AFM images) organization levels. The calculated CP channel-related ...

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    2. Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography

      Characterization of atherosclerotic plaques by cross-polarization optical coherence tomography

      We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers in the development of the atherosclerotic plaque (AP). The study shows potential of CP OCT for the assessment of collagen and elastin fibers condition in atherosclerotic arteries. Specifically, the additional information afforded by CP OCT, related to birefringence and cross-scattering properties of arterial tissues, may improve the robustness and accuracy of assessment about the microstructure and composition of the plaque for different stages of atherosclerosis.

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    3. Multi-modal optical imaging characterization of atherosclerotic plaques

      Multi-modal optical imaging characterization of atherosclerotic plaques

      We combined cross-polarization optical coherence tomography (CP OCT) and non-linear microscopy based on second harmonic generation (SHG) and two-photon-excited fluorescence (2PEF) to assess collagen and elastin fibers and other vascular structures in the development of atherosclerosis, including identification of vulnerable plaques, which remains an important clinical problem and imaging application. CP OCT's ability to visualize tissue birefringence and cross-scattering adds new information about the microstructure and composition of the plaque. However its interpretation can be ambiguous, because backscattering contrast may have a similar appearance to the birefringence related fringes. Our results represent a step towards minimally invasive characterization and ...

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    4. Optical coherence tomography device and method having improved boundary control and distortion correction

      Optical coherence tomography device and method having improved boundary control and distortion correction

      Variants of an interferometric device are developed for examining internal structures of objects by means of optical coherence tomography, which allow for controlling a boundary location of the observation range. The device also allows for correcting a distortion of the tomographic image of the object under study, caused by lateral scanning, due to aberrations of the optical path length for the low-coherence optical radiation directed towards the object. Embodiments of the device include either one, or two fiber-optic controlled scanners, which in different combinations perform a function of in-depth scanning of the coherence window of low-coherence optical radiation within the ...

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    5. Common path systems and methods for frequency domain and time domain optical coherence tomography using non-specular reference reflection and a delivering device for optical radiation with a partially optically transparent non-specular reference reflector

      Common path systems and methods for frequency domain and time domain optical coherence tomography using non-specular reference reflection and a delivering device for optical radiation with a partially optically transparent non-specular reference reflector
      Provided are common path frequency domain and time domain OCT systems and methods that use non-specular reference reflection for obtaining internal depth profiles and depth resolved images of samples. Further provided is a delivering device for optical radiation, preferably implemented as an optical fiber probe with a partially optically transparent non-specular reflector placed in the vicinity of an associated sample. High frequency fringes are substantially reduced and a stable power level of the reference reflection is provided over the lateral scanning range. The partially optically transparent non-specular reflector is implemented as a coating placed on the interior surface of the ...
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    6. Polarization-sensitive common path optical coherence reflectometry/tomography device

      Polarization-sensitive common path optical coherence reflectometry/tomography device
      Polarization sensitive common path OCT/OCR devices are presented. Optical radiation from a source is converted into two cross-polarized replicas propagating therethrough with a predetermined optical path length difference. The two cross-polarized replicas are then delivered to an associated sample by a delivering device, which is, preferably, an optical fiber probe. A combination optical radiation is produced in at least one secondary interferometer by combining a corresponding portion of an optical radiation returning from the associated sample with a reference optical radiation reflected from a tip of an optical fiber of the optical fiber probe. Subject to a preset optical ...
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    7. Feature Of The Week 9/27/09: Collective Dynamics of Swimming Bacteria: OCT Studies

      Feature Of The Week 9/27/09: Collective Dynamics of Swimming Bacteria: OCT Studies

      Feature Of The Week 9/27/09: Physical mechanisms governing large-scale organization of self-propelled biological microparticles, such as motor proteins, swimming bacteria, and other motile cells, attract significant attention among physicists and biologists. Scientists from Argonne National Laboratory, Imalux, and Cambridge University, discovered that commonly found bacteria such as Bacillus Subtilis are in fact highly efficient mixers for the liquid they live in. Thanks to original non-invasive optical coherence tomography developed by Imalux Corporation, OH, the scientists observed with unprecedented precision the phenomena unfolding in the liquid containing the bacterial suspension. The measurements revealed up to 100-fold increase of mixing ...

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    8. Enhanced mixing and spatial instability in concentrated bacterial suspensions

      High-resolution optical coherence tomography is used to study the onset of a large-scale convective motion in free-standing thin films of adjustable thickness containing suspensions of swimming aerobic bacteria. Clear evidence is found that beyond a threshold film thickness there exists a transition from quasi-two-dimensional collective swimming to three-dimensional turbulent behavior. The latter state, qualitatively different from bioconvection in dilute bacterial suspensions, is characterized by enhanced diffusivities of oxygen and bacteria. These results emphasize the impact of self-organized bacterial locomotion on the onset of three-dimensional dynamics, and suggest key ingredients necessary to extend standard models of bioconvection to incorporate effects of ...
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    9. Optoelectronic probe system with all-optical coupling

      An optoelectronic probe system with all-optical coupling includes an optoelectronic measuring console coupled with an optoelectronic probe via an optical connector. A supplemental optical signal having an operative wavelength other than an operative wavelength of the regular optical part of the optoelectronic measuring console is communicated to the optoelectronic probe along with the output signal from the optoelectronic measuring console. The supplemental optical signal is then selected by a wavelength-division multiplexer, converted to an electrical signal and used for powering respective components of the optoelectronic probe. Auxiliary signals are also used for identification and storing calibration parameters of the optoelectronic ...
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    10. Common path time domain optical coherence reflectometry/tomography device

      In common path time domain OCT/OCR devices optical radiation from a source is first split into two replicas, which are then delivered to an associated sample by an optical fiber probe. The tip of the optical fiber probe serves as a reference reflector and also serves as a combining element that produces a combination optical radiation by combining an optical radiation returning from the associated sample with a reference optical radiation reflected from the reference reflector. The topology of the devices eliminates the necessity of using Faraday mirrors, and also allows for registering a cross-polarized component of the optical ...
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    11. Common path frequency domain optical coherence reflectometry/tomography device

      BACKGROUND OF THE INVENTION The present invention relates to systems and methods for visualizing subsurface regions of samples, and more specifically, to a frequency domain optical coherence reflectometer and frequency domain optical coherence tomography (OCT) device thatprovides internal depth profiles and depth resolved images of samples.Optical coherence reflectometry/tomography involves splitting an optical radiation into at least two portions, and directing one portion of the optical radiati
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    12. Common path frequency domain optical coherence reflectometer and common path frequency domain optical coherence tomography device

      BACKGROUND OF THE INVENTIONThe present invention relates to systems and methods for visualizing subsurface regions of samples, and more specifically, to a frequency domain optical coherence reflectometer and frequency domain optical coherence tomography (OCT) device thatprovides internal depth profiles and depth resolved images of samples.Optical coherence reflectometry/tomography involves splitting an optical radiation to at least two portions, and directing one portion of the optical radiation
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    13. Common Path Systems And Methods For Frequency Domain And Time Domain Optical Coherence Tomography Using Non-Specular Reference Reflection And A Delivering Device For Optical Radiation With A Partially Optically Transparent Non-Specular Reference Reflector

      Common Path Systems And Methods For Frequency Domain And Time Domain Optical Coherence Tomography Using Non-Specular Reference Reflection And A Delivering Device For Optical Radiation With A Partially Optically Transparent Non-Specular Reference Reflector
      Provided are common path frequency domain and time domain OCT systems and methods that use non-specular reference reflection for obtaining internal depth profiles and depth resolved images of samples. Further provided is a delivering device for optical radiation, preferably implemented as an optical fiber probe with a partially optically transparent non-specular reflector placed in the vicinity of an associated sample. High frequency fringes are substantially reduced and a stable power level of the reference reflection is provided over the lateral scanning range. The partially optically transparent non-specular reflector is implemented as a coating placed on the interior surface of the ...
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    14. Optical fiber lateral scanner for a miniature optical fiber probe

      The present invention relates to an optical fiber magnetic scanning arrangement for a miniature optical fiber probe and can be applied for optical beam delivery in various optical imaging techniques. The arrangement is of the type where an optical fiber is rigidly fixed to a current conductor and serving as a flexible cantilever with a capability for the distal part of the optical fiber of being deflected in a direction substantially orthogonal to its own axis. New designs of the magnetic system are less critical to the shape and dimensional tolerances of scanner elements and assembly. These designs provide a ...
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    15. Calibration tool for an optical measuring device with an optical fiber probe

      An optical measurement device calibration tool includes an optical probe suitable for calibrating various optical imaging devices, for example, low coherence reflectometers and optical coherence tomography devices. In a preferred embodiment the calibration tool comprises a container containing a calibration substance with stable optical scattering and absorption properties. The calibration substance includes a gel, paste or grease substance and is covered a protective seal, which is at least partially transparent providing optical contact between the optical probe and the calibration substance. The protective seal is covered with a viscous complementary material. Another protective seal made at least partially removable is ...
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    16. Method for studying a sample and optical interferometer for doing the same

      The present invention relates to the study of internal structure of objects by optical means. The invention presents a bi-directional sampling optical path for the low coherent optical radiation directed to the sample, i.e. a bi-directional sampling arm, and two unidirectional reference beams directed along a reference path designed as a loop. One of the reference beams propagates clockwise and the other propagates counterclockwise in the reference loop. The beam splitters non-reciprocal or polarization-dependent and by placing polarization-changing elements between the beam splitters and/or into the sampling arm and the reference loop. Thus the developed method and optical ...
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    17. Optical coherence tomography apparatus, optical fiber lateral scanner and a method for studying biological tissues in vivo

      In a method for in vivo diagnostics of a biological tissue covered with epithelium an image of the biological tissue is acquired with the aid of a beam in the visible or near IR range directed towards a biological tissue by visualizing the intensity of optical radiation backscattered by the biological tissue. The basal membrane of said biological tissue, which separates the epithelium from an underlying stroma, is identified in the acquired image and diagnostics is performed on basis of the form of the basal membrane. For diagnostics of biological tissue lining the surface of cavities and internal organs of ...
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    18. Optical coherence tomography apparatus, optical fiber lateral scanner and a method for studying biological tissues in vivo

      The present invention relates to the analysis of the internal structures of objects using optical means. According to the invention there were designed an apparatus suited for optical coherence tomography (OCT), an optical fiber lateral scanner (15), which is a part of said apparatus and is incorporated into an optical fiber probe (8), and a method for studying biological tissue in vivo, which allows for making a diagnostics of the biological tissue under study on basis of the state of the basal membrane (46). The moving part of lateral scanner (15) of sampling arm (4) of interferometer (2) is arranged ...
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    19. Optical coherent tomography apparatus, fiberoptic lateral scanner and method for studying biological tissues in vivo

      The present invention relates to the analysis of the internal structures of objects using optical means. According to the invention there were designed an apparatus suited for optical coherence tomography (OCT), an optical fiber lateral scanner (15), which is a part of said apparatus and is incorporated into an optical fiber probe (8), and a method for studying biological tissue in vivo, which allows for making a diagnostics of the biological tissue under, study on basis of the state of the basal membrane (46). The moving part of lateral scanner (15) of sampling arm (4) of interferometer (2) is arranged ...
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    20. Optical fiber interferometer with PZT scanning of interferometer arm optical length

      The invention is related to technical physics, in particular to devices for investigating the internal structure of objects and can be used in medicine for diagnostics of human organs and systems, in particular for optical coherence tomography and in technical diagnostics, for example technological process control. The invention relates to the creation of an optical-fiber interferometer, which, being used in a device for optical coherence tomography, allows one to investigate media with short time of changing of optical characteristics or its position relative to the optical probe, for example biotissues in vivo. The invention also relates to the creation of ...
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    21. Optical fiber interferometer and piezoelectric modulator

      The invention is related to technical physics, in particular to devices for investigating the internal structure of objects and can be used in medicine for diagnostics of human organs and systems, in particular for optical coherence tomography and in technical diagnostics, for example technological process control. The invention relates to the creation of an optical-fiber interferometer, which, being used in a device for optical coherence tomography, allows one to investigate media with short time of changing of optical characteristics or its position relative to the optical probe, for example biotissues in vivo. The invention also relates to the creation of ...
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    1-21 of 21
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  2. Topics in the News

    1. (21 articles) Felix I. Feldchtein
    2. (18 articles) Imalux
    3. (14 articles) Grigory V. Gelikonov
    4. (11 articles) Institute of Applied Physics
    5. (9 articles) Valentin M. Gelikonov
    6. (8 articles) Natalia D. Gladkova
    7. (5 articles) Alexander M. Sergeev
    8. (3 articles) Nizhny Novgorod State Medical Academy
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