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    1. Mentioned In 1050 Articles

    2. Extended depth of focus by self-imaging wavefront division with the mirror tunnel

      Extended depth of focus by self-imaging wavefront division with the mirror tunnel
      The mirror tunnel is a component used to extend the depth of focus for compact imaging probes used in endoscopic optical coherence tomography (OCT). A fast and accurate method for mirror tunnel probe simulation, characterization, and optimization is needed, with the aim of reconciling wave- and ray-optics simulation methods and providing a thorough description of the physical operating principle of the mirror tunnel. BeamLab software, employing the beam propagation method ...
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    3. Apparatus, device and method for capsule microscopy

      Apparatus, device and method for capsule microscopy
      An exemplary apparatus for obtaining data for at least one portion within at least one luminal or hollow sample can be provided. For example, the apparatus can include a first optical arrangement configured to transceive at least one electromagnetic radiation to and from the portion(s). The apparatus can also include a wavelength dispersive second arrangement, which can be configured to disperse the electromagnetic radiation(s). A housing can be ...
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    4. RF properties of circular-ranging OCT signals

      RF properties of circular-ranging OCT signals
      Circular-ranging optical coherence tomography (CROCT) systems that use a timestepped frequency comb source generate interference fringe signals that are more complex than those of a conventional sweptsource OCT system. Here, we define a common terminology for describing these signals, and we develop a mathematical framework that relates the radio-frequency (RF) properties of these fringe signals to the parameters of the frequency comb source. With this framework, we highlight non-intuitive mechanisms ...
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    5. Raman microspectroscopy/micro-optical coherence tomography approach for chairside diagnosis of periodontal diseases - A pilot study

      Raman microspectroscopy/micro-optical coherence tomography approach for chairside diagnosis of periodontal diseases - A pilot study
      Background: Our objective was to develop and test a combined Raman microspectroscopy (RMS) and micro-optical coherence tomography (OCT) approach for chairside quantification of gingival collagen, DNA, epithelium and connective tissue. We hypothesized that a high-resolution RMS/OCT can characterize healthy and inflamed periodontal tissues for diagnosis and disease activity monitoring. Methods: A prototype instrument was developed, tested ex-vivo on gingival specimens and optimized for in-vivo intraoral use. The primary outcome ...
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    6. Relationship between axial resolution and signal-to-noise ratio in optical coherence tomography

      Relationship between axial resolution and signal-to-noise ratio in optical coherence tomography
      In optical coherence tomography (OCT), axial resolution and signal-to-noise ratio (SNR) are typically viewed as uncoupled parameters. We show that this is true only for mirror-like surfaces and that in diffuse scattering samples such as biological tissues there is an inherent coupling between axial resolution and measurement SNR. We explain the origin of this coupling and demonstrate that it can be used to achieve increased imaging penetration depth at the ...
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    7. Impact and implications of mixed plaque class in automated characterization of complex atherosclerotic lesions

      Impact and implications of mixed plaque class in automated characterization of complex atherosclerotic lesions
      Atherosclerosis is a complex disease altering vasculature morphology, and subsequently flow, with progressive plaque formation, mural disruption, and lumen occlusion. Determination of clinically-relevant plaque componentsparticularly calcium, lipid, and fibrous tissuehas driven automated image-based tissue characterization. Atherosclerotic tissue of mixed composition type arises when these principal components interdigitate and combine during the course of progressive atherosclerosis. Nevertheless, such mixed plaque is treated non-uniformly, and often neglected, as a distinct class in ...
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    8. Is Real-Time Microscopy on the Horizon? A Brief Review of the Potential Future Directions in Clinical Breast Tumor Microscopy Implementation

      Is Real-Time Microscopy on the Horizon? A Brief Review of the Potential Future Directions in Clinical Breast Tumor Microscopy Implementation
      We will briefly review the current paradigm and some recent developments in the area of clinical breast microscopy, highlighting several promising commercially available, and research-based platforms. Confocal microscopy (reflectance, fluorescence, and spectrally encoded), optical coherence tomography (wide field and full field), stereomicroscopy, open-top light sheet microscopy, microscopy with ultraviolet surface excitation, nonlinear microscopy, Raman scattering microscopy, photoacoustic microscopy, and needle microendoscopy will be discussed. Non-microscopic methods for breast pathology assessment ...
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    9. Cochlear Fluid Spaces and Structures of the Gerbil High-Frequency Region Measured Using Optical Coherence Tomography (OCT)

      Cochlear Fluid Spaces and Structures of the Gerbil High-Frequency Region Measured Using Optical Coherence Tomography (OCT)
      Since it has been difficult to directly observe the morphology of the living cochlea, our ability to infer the mechanical functioning of the living ear has been limited. Nearly all our knowledge about cochlear morphology comes from postmortem tissue that was fixed and processed using procedures that possibly distort the structures and fluid spaces of the organ of Corti. In this study, optical coherence tomography was employed to obtain volumetric ...
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    10. Non-destructive mapping of stress, strain and stiffness of thin elastically deformed materials

      Non-destructive mapping of stress, strain and stiffness of thin elastically deformed materials
      Knowing the stress within a soft material is of fundamental interest to basic research and practical applications, such as soft matter devices, biomaterial engineering, and medical sciences. However, it is challenging to measure stress fields in situ in a non-invasive way. It becomes even more difficult if the mechanical properties of the material are unknown or altered by the stress. Here we present a robust non-destructive technique capable of measuring ...
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    11. Refractive-index matching enhanced polarization sensitive optical coherence tomography quantification in human brain tissue

      Refractive-index matching enhanced polarization sensitive optical coherence tomography quantification in human brain tissue
      The importance of polarization-sensitive optical coherence tomography (PS-OCT) has been increasingly recognized in human brain imaging. Despite the recent progress of PS-OCT in revealing white matter architecture and orientation, quantification of fine-scale fiber tracts in the human brain cortex has been a challenging problem, due to a low birefringence in the gray matter. In this study, we investigated the effect of refractive index matching by 2,2-thiodiethanol (TDE) immersion on ...
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    12. Using the Dynamic Forward Scattering Signal for Optical Coherence Tomography based Blood Flow Quantification

      Using the Dynamic Forward Scattering Signal for Optical Coherence Tomography based Blood Flow Quantification
      To our knowledge, all existing optical coherence tomography approaches for quantifying blood flow, whether Doppler-based or decorrelation-based, analyze the light that is back-scattered by moving red blood cells (RBCs). This work investigates the potential advantages of basing these measurements of the light that is forward-scattered by RBCs, i.e., by looking at the signals back-scattered from below the vessel. We show experimentally that this results in a flowmetry measure that ...
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    13. Histopathological correlation of near infrared autofluorescence in human cadaver coronary arteries

      Histopathological correlation of near infrared autofluorescence in human cadaver coronary arteries
      Background and aims Prior coronary optical coherence tomography (OCT)-near infrared fluorescence (NIRAF) imaging data has shown a correlation between high-risk morphological features and NIRAF signal intensity. This study aims to understand the histopathological origins of NIRAF in human cadaver coronary arteries. Methods Ex vivo intracoronary OCT-NIRAF imaging was performed on coronary arteries prosected from 23 fresh human cadaver hearts. Arteries with elevated NIRAF were formalin-fixed and paraffin-embedded. Microscopic images ...
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    14. Optical design, optimization and validation of an extended-depth-of-field optical coherence tomography probe based on mirror-tunneling

      Optical design, optimization and validation of an extended-depth-of-field optical coherence tomography probe based on mirror-tunneling
      We present results from optimizing mirror-tunnel based optical coherence tomography probes, achieving extended depth of field at high resolution. We achieved 6 m spot diameter over 1 mm depth in simulations and validated experimentally.
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    15. 16-30 of 1050 « 1 2 3 4 5 ... 68 69 70 »
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  2. About Harvard University

    Harvard University

    Harvard University is a private university in Cambridge, Massachusetts, U.S. Founded in 1636 by the colonial Massachusetts legislature Harvard is the oldest institution of higher learning in the United States.  Harvard Medical School  is one of the graduate schools of Harvard University. It is a prestigious American medical school located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts.  Schepens Eye Research Institute fights blindness by developing new technologies, therapies and knowledge to retain and restore vision. Through a continuum of discovery, the Institute works toward a future in which blindness is prevented, alleviated, and, ultimately, cured.