1. Articles from Karol Karnowski

    1-24 of 27 1 2 »
    1. Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo

      Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo

      Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly ex vivo by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa in vivo . Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial ...

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    2. Assistant professor (post-doc) in the Department of Physical Chemistry of Biological Systems at Polish Academy of Sciences

      Assistant professor (post-doc) in the Department of Physical Chemistry of Biological Systems at Polish Academy of Sciences

      We encourage applicants for Assistant professor (post-doc) position in the Department of Physical Chemistry of Biological Systems at Institute of Physical Chemistry PAS, Warsaw, Poland. This position is a part of the RETURNS project funded by the Polish National Agency For Academic Exchange (NAWA). The Return Project is targeted at development of enhanced polarization contrast optical tomography to improve the outcomes of automatic localization and characterization of malignant tissue Eligibility criteria: PhD degree in engineering, physics, computer science, mathematics, physiology, biology, or similar; or equivalent industry experience; Track record of achievements relative to opportunity; Experience (2-4 years) in at least ...

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      Mentions: Karol Karnowski
    3. Postdoc in Optics and Biophotonics in the Department of Physical Chemistry of Biological Systems at the Polish Academy of Sciences

      Postdoc in Optics and Biophotonics in the Department of Physical Chemistry of Biological Systems at the Polish Academy of Sciences

      We encourage applicants for Assistant professor (post-doc) position in the Department of Physical Chemistry of Biological Systems at Institute of Physical Chemistry PAS, Warsaw, Poland. This position is a part of the RETURNS project funded by the Polish National Agency For Academic Exchange (NAWA). The RETURNS Project is targeted at development of enhanced polarization contrast optical tomography to improve the outcomes of automatic localization and characterization of malignant tissue. Eligibility criteria: PhD degree in engineering, physics, computer science, mathematics, physiology, biology, or similar; Track record of achievements relative to opportunity; Experience (2-4 years) in at least one of: optical coherence ...

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      Mentions: Karol Karnowski
    4. Robust reconstruction of local optic axis orientation with fiber-based polarization-sensitive optical coherence tomography

      Robust reconstruction of local optic axis orientation with fiber-based polarization-sensitive optical coherence tomography

      It is challenging to recover local optic axis orientation from samples probed with fiber-based polarization-sensitive optical coherence tomography (PS-OCT). In addition to the effect of preceding tissue layers, the transmission through fiber and system elements, and imperfect system alignment, need to be compensated. Here, we present a method to retrieve the required correction factors from measurements with depth-multiplexed PS-OCT, which accurately measures the full Jones matrix. The correction considers both retardation and diattenuation and is applied in the wavenumber domain, preserving the axial resolution of the system. The robustness of the method is validated by measuring a birefringence phantom with ...

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    5. Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis

      Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis

      Application of the air‐puff swept source OCT (SS‐OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air‐puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time‐evolution of the tissue displacement and air pulse stimulus allows obtaining valuable information related in part to the mechanical properties of the cornea. A novel approach based on quantitative analysis of the corneal hysteresis of OCT data is presented. The corneal response to the air pulse is assessed for different well‐controlled IOP levels and for the progression of ...

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    6. Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      Label‐free volumetric imaging of conjunctival collecting lymphatics ex vivo by optical coherence tomography lymphangiography

      We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo . This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM scans at 785 nm reveal the lymphatic vessels via their optical transparency. Equivalent signal characteristics are also observed from blood vessels largely free of blood (and devoid of flow) in the ex vivo conjunctiva. In our lymphangiography, vessel networks were segmented by compensating the depth attenuation in ...

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    7. A study of the effects of supine position and fluid intake on normal airway geometry using anatomical optical coherence tomography

      A study of the effects of supine position and fluid intake on normal airway geometry using anatomical optical coherence tomography

      Airway inhalation injuries are present in up to a third of all major burns patients and are the leading cause of mortality among this population. Understanding the mechanism of injury could minimise oedema (swelling) and airway damage. In this study, we present an anatomical OCT (aOCT) imaging system, based on a 1300-nm wavelength, high-speed, long-range MEMS-VCSEL swept laser source, for real-time volumetric imaging and assessment of inhalation injuries in airways up to 3 cm in diameter. A custom fibre-optic probe with GRIN lens and micro prism is inserted though the nasal passage. Airway cross-sectional images acquired are used to assess ...

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    8. Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye

      Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye

      Standard optical systems in ophthalmology are strictly dedicated either to retinal or to anterior segment imaging due to the refractive properties of the eye. We demonstrate a swept source optical coherence tomography platform with an electrically tunable lens (ETL) for versatile 3D in vivo imaging of both the eye’s anterior segment and the retina. The optimized optical setup with adaptive operational states of the ETL permits focusing on the retina and on the anterior segment. Dynamic control of the optical beam focus allows for OCT image enhancement, leading to the visualization of the vitreous details at both the vitreo-lenticular ...

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    9. Research Associate / Research Fellow Microscope-in-a-Needle at the University of Western Australia

      Research Associate / Research Fellow Microscope-in-a-Needle at the University of Western Australia

      Job no: 499437 Work type: full-time Location: Crawley Categories: Health and Medical Sciences, Engineering and Mathematical Sciences 1 year appointment Salary range: Level A $67,352 - $91,397 p.a. or Level B $96,210 - $114,250 p.a. (dependent on qualifications and experience) Research & Development In Biomedical Photonics/Optical Microscopy (Australia) The University of Western Australia (UWA) is ranked amongst the top Australian universities and a member of the prestigious Group of Eight research-intensive universities ranked among the top 100 universities in the world. Do you have an aptitude for opto-mechanics and/or robotics? Come join a team of ...

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    10. Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos

      Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos

      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging techniques and provides unique access to fundamental aspects of early embryonic development, without the requirement for sample pre-processing or labeling. In the present paper, we utilized the internal motion of ...

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    11. Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Optical coherence microscopy as a novel, non-invasive method for the 4D live imaging of early mammalian embryos

      Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular architecture without causing short- and long-term photodamage. Optical coherence microscopy (OCM) is a promising alternative that circumvents the technical limitations of fluorescence imaging techniques and provides unique access to fundamental aspects of early embryonic development, without the requirement for sample pre-processing or labeling. In the present paper, we utilized the internal motion of ...

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    12. Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography

      Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography

      In this paper, we use swept source optical coherence tomography combined with air-puff module (air-puff SS-OCT) to investigate the properties of the cornea. During OCT measurement the cornea was stimulated by short, air pulse, and corneal response was recorded. In this preliminary study, the air-puff SS-OCT instrument was applied to measure behavior of the porcine corneas under varied, well-controlled intraocular pressure conditions. Additionally, the biomechanical response of the corneal tissue before, during and after crosslinking procedure (CXL) was assessed. Air-puff swept source OCT is a promising tool to extract information about corneal behavior as well as to monitor and assess ...

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    13. Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction

      Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction

      A novel, time-resolved interferometric technique is presented allowing the reconstruction of the complex electric field output of a fast frequency swept laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography applications, with a spectral bandwidth of 18 THz. This novel analysis of the complete electric field reveals the modal structure and modal evolution of the device as well as providing a time-resolved real-time characterization of the optical spectrum, linewidth and coherence properties of a dynamic rapidly swept laser.

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    14. Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women

      Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women

      The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo , micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm 2 of the mucosa of the lower lip to the depth of 3.4 mm in young ( n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m ...

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    15. Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm2 and 6.58 glands/cm2, respectively (p = 0.006; Mann-Whitney U test). A ...

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    16. Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm 2 and 6.58 glands/cm 2 , respectively (p = 0.006; Mann-Whitney U ...

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    17. Feature Of The Week 11/9/14: Dynamics of a Short Cavity Swept Source OCT Laser

      Feature Of The Week 11/9/14: Dynamics of a Short Cavity Swept Source OCT Laser

      Great advances in OCT speed and sensitivity have been possible due to the introduction of fast frequency swept laser sources. One of the most commonly used swept source devices is a short (~5 cm) cavity Fabry-Perot laser. We present both experimental characterisation and numerical modelling of such an OCT swept source and also analyse the underlying physics to better understand how such sources may be optimised. For the experimental characterisation we use a high-speed digital oscilloscope for real time analysis of the fast temporal intensity and frequency evolution. For the theoretical analysis we use a set of delay differential equations ...

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    18. Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT

      Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT

      We demonstrate swept source optical coherence tomography (OCT) imaging of contact lenses (CLs) in a wet cell and comprehensive quantitative characterization of CLs from volumetric OCT datasets. The approach is based on a technique developed for lens autopositioning and autoleveling enabled by lateral capillary interactions between the wet cell wall and the lens floating on the liquid surface. The demonstrated OCT imaging has enhanced contrast due to the application of a scattering medium and it improves visualization of both CL interfaces and edges. We also present precise and accurate three-dimensional metrology of soft and rigid CLs based on the OCT ...

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    19. Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT

      Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT

      Three-dimensional imaging of the mucosa of the lower lip and labial minor salivary glands is demonstrated in vivo using swept source optical coherence tomography (OCT) system at 1310 nm with modified interface. Volumetric data sets of the inner surface of the lower lip covering ~230 mm 2 field are obtained from patients with Sjögren’s syndrome and a control group. OCT enables high-resolution visualization of mucosal architecture using cross-sectional images as well as en-face projection images. Comprehensive morphometry of the labial minor salivary glands is performed, and statistical significance is assessed. Statistically significant differences in morphometric parameters are found ...

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    20. Improved measurement of vibration amplitude in dynamic optical coherence elastography

      Improved measurement of vibration amplitude in dynamic optical coherence elastography

      Optical coherence elastography employs optical coherence tomography (OCT) to measure the displacement of tissues under load and, thus, maps the resulting strain into an image, known as an elastogram. We present a new improved method to measure vibration amplitude in dynamic optical coherence elastography. The tissue vibration amplitude caused by sinusoidal loading is measured from the spread of the Doppler spectrum, which is extracted using joint spectral and time domain signal processing. At low OCT signal-to-noise ratio (SNR), the method provides more accurate vibration amplitude measurements than the currently used phase-sensitive method. For measurements performed on a mirror at OCT ...

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    21. Fourier domain OCT imaging of American cockroach nervous system

      Fourier domain OCT imaging of American cockroach nervous system

      In this pilot study we demonstrate results of structural Fourier domain OCT imaging of the nervous system of Periplaneta americana L. (American cockroach). The purpose of this research is to develop an OCT apparatus enabling structural imaging of insect neural system. Secondary purpose of the presented research is to develop methods of the sample preparation and handling during the OCT imaging experiments. We have performed imaging in the abdominal nerve cord excised from the American cockroach. For this purpose we have developed a Fourier domain / spectral OCT system operating at 820 nm wavelength range.

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    22. Feature Of The Week 11/6/11: Nicolaus Copernicus University Researchers Develop Technique to Study Biomechanical Properties of The Cornea Using OCT

      Feature Of The Week 11/6/11: Nicolaus Copernicus University Researchers Develop Technique to Study Biomechanical Properties of The Cornea Using OCT
      Researchers from Nicolaus Copernicus University have a long history of development of OCT in general and ophthalmology in particular. Recently NCU developed a technique to study the mechanical dynamics of the cornea using high speed OCT combined with an air puff system. Below is a summary of their work.We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream ...
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    23. Corneal topography with high-speed swept source OCT in clinical examination

      Corneal topography with high-speed swept source OCT in clinical examination
      We present the applicability of high-speed swept source (SS) optical coherence tomography (OCT) for quantitative evaluation of the corneal topography. A high-speed OCT device of 108,000 lines/s permits dense 3D imaging of the anterior segment within a time period of less than one fourth of second, minimizing the influence of motion artifacts on final images and topographic analysis. The swept laser performance was specially adapted to meet imaging depth requirements. For the first time to our knowledge the results of a quantitative corneal analysis based on SS OCT for clinical pathologies such as keratoconus, a cornea with superficial ...
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    24. Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system

      Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system
      We present a novel method and instrument for in vivo imaging and measurement of the human corneal dynamics during an air puff. The instrument is based on high-speed swept source optical coherence tomography (ssOCT) combined with a custom adapted air puff chamber from a non-contact tonometer, which uses an air stream to deform the cornea in a non-invasive manner. During the short period of time that the deformation takes place, the ssOCT acquires multiple A-scans in time (M-scan) at the center of the air puff, allowing observation of the dynamics of the anterior and posterior corneal surfaces as well as ...
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    1-24 of 27 1 2 »
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    1. (27 articles) Karol Karnowski
    2. (20 articles) Nicolaus Copernicus University
    3. (19 articles) Maciej Wojtkowski
    4. (9 articles) Ireneusz Grulkowski
    5. (7 articles) University of Western Australia
    6. (7 articles) Bartlomiej J. Kaluzny
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    Ultra high-speed swept source OCT imaging of the anterior segment of human eye at 200 kHz with adjustable imaging range Assessment of corneal dynamics with high-speed swept source Optical Coherence Tomography combined with an air puff system Corneal topography with high-speed swept source OCT in clinical examination Feature Of The Week 11/6/11: Nicolaus Copernicus University Researchers Develop Technique to Study Biomechanical Properties of The Cornea Using OCT Fourier domain OCT imaging of American cockroach nervous system Feature Of The Week 11/9/14: Dynamics of a Short Cavity Swept Source OCT Laser Coherence properties of fast frequency swept lasers revealed via full electric field reconstruction Feature Of The Week 10/08/2017: Optical Coherence Microscopy as a Novel, Non-Invasive Method for the 4D Live Imaging of Early Mammalian Embryos Measurement of the Shrinkage of Natural and Simulated Lesions on Root Surfaces using CP-OCT Optic-Net: A Novel Convolutional Neural Network for Diagnosis of Retinal Diseases from Optical Tomography Images Double layer sign: A new optical coherence tomography finding in active tubercular serpiginous-like choroiditis to monitor activity Influence of Epiretinal Membranes on the Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography in Glaucoma