1. Articles from Peter Cimalla

    1-24 of 27 1 2 »
    1. Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT

      Advanced analysis of domain walls in Mg doped LiNbO3 crystals with high resolution OCT

      The structure of domain walls (DW) in ferroelectric media is of great interest as this material is used for frequency doublers and other applications. We show that the structure of the DWs can nicely be visualized by high resolution optical coherence tomography (OCT). While the high group refractive index of lithium niobate allows a resolution much better than 1 µm, the large dispersion can blur the image and has to be compensated. Therefore, we developed an adaptive dispersion compensation algorithm based on maximizing the intensity of the DWs. By measuring a group of DWs, the mean period of the DWs ...

      Read Full Article
    2. Improved Imaging of Magnetically Labeled Cells Using Rotational Magnetomotive Optical Coherence Tomography

      Improved Imaging of Magnetically Labeled Cells Using Rotational Magnetomotive Optical Coherence Tomography

      Abstract In this paper, we present a reliable and robust method for magnetomotive optical coherence tomography (MM-OCT) imaging of single cells labeled with iron oxide particles. This method employs modulated longitudinal and transverse magnetic fields to evoke alignment and rotation of anisotropic magnetic structures in the sample volume. Experimental evidence suggests that magnetic particles assemble themselves in elongated chains when exposed to a permanent magnetic field. Magnetomotion in the intracellular space was detected and visualized by means of 3D OCT as well as laser speckle reflectometry as a 2D reference imaging method. Our experiments on mesenchymal stem cells embedded in ...

      Read Full Article
    3. NADPH oxidase 4 protects against development of endothelial dysfunction and atherosclerosis in LDL receptor deficient mice

      NADPH oxidase 4 protects against development of endothelial dysfunction and atherosclerosis in LDL receptor deficient mice

      Aims Endothelial dysfunction is an early step in the development of atherosclerosis. Increased formation of superoxide anions by NADPH oxidase Nox1, 2, and 5 reduces nitric oxide availability and can promote endothelial dysfunction. In contrast, recent evidence supports a vasoprotective role of H 2 O 2 produced by main endothelial isoform Nox4. Therefore, we analysed the impact of genetic deletion of Nox4 on endothelial dysfunction and atherosclerosis in the low-density lipoprotein receptor (Ldlr) knockout model. Methods and results Ex vivo analysis of endothelial function by Mulvany myograph showed impaired endothelial function in thoracic aorta of Nox4 −/− /Ldlr −/− mice. Further progression ...

      Read Full Article
    4. Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy

      Imaging of nanoparticle-labeled stem cells using magnetomotive optical coherence tomography, laser speckle reflectometry, and light microscopy

      Cell transplantation and stem cell therapy are promising approaches for regenerative medicine and are of interest to researchers and clinicians worldwide. However, currently, no imaging technique that allows three-dimensional in vivo inspection of therapeutically administered cells in host tissues is available. Therefore, we investigate magnetomotive optical coherence tomography (MM-OCT) of cells labeled with magnetic particles as a potential noninvasive cell tracking method. We develop magnetomotive imaging of mesenchymal stem cells for future cell therapy monitoring. Cells were labeled with fluorescent iron oxide nanoparticles, embedded in tissue-mimicking agar scaffolds, and imaged using a microscope setup with an integrated MM-OCT probe. Magnetic ...

      Read Full Article
    5. Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      Towards a comprehensive eye model for zebrafish retinal imaging using full range spectral domain optical coherence tomography

      In regenerative medicine, the zebrafish is a prominent animal model for studying degeneration and regeneration processes, e.g. of photoreceptor cells in the retina. By means of optical coherence tomography (OCT), these studies can be conducted over weeks using the same individual and hence reducing the variability of the results. To allow an improvement of zebrafish retinal OCT imaging by suitable optics, we developed a zebrafish eye model using geometrical data obtained by in vivo dispersion encoded full range OCT as well as a dispersion comprising gradient index (GRIN) lens model based on refractive index data found in the literature ...

      Read Full Article
    6. Characterization of Light Lesion Paradigms and Optical Coherence Tomography as Tools to Study Adult Retina Regeneration in Zebrafish

      Characterization of Light Lesion Paradigms and Optical Coherence Tomography as Tools to Study Adult Retina Regeneration in Zebrafish

      Light-induced lesions are a powerful tool to study the amazing ability of photoreceptors to regenerate in the adult zebrafish retina. However, the specificity of the lesion towards photoreceptors or regional differences within the retina are still incompletely understood. We therefore characterized the process of degeneration and regeneration in an established paradigm, using intense white light from a fluorescence lamp on swimming fish (diffuse light lesion). We also designed a new light lesion paradigm where light is focused through a microscope onto the retina of an immobilized fish (focused light lesion). Focused light lesion has the advantage of creating a locally ...

      Read Full Article
    7. High-resolution optical coherence tomography in mouse models of genetic and induced retinal degeneration

      High-resolution optical coherence tomography in mouse models of genetic and induced retinal degeneration

      For the study of disease mechanisms and the development of novel therapeutic strategies for retinal pathologies in human, rodent models play an important role. Nowadays, optical coherence tomography (OCT) allows three-dimensional investigation of retinal events over time. However, a detailed analysis of how different retinal degenerations are reflected in OCT images is still lacking in the biomedical field. Therefore, we use OCT to visualize retinal degeneration in specific mouse models in order to study disease progression in vivo and improve image interpretation of this noninvasive modality. We use a self-developed spectral domain OCT system for simultaneous dual-band imaging in the ...

      Read Full Article
    8. Magnetomotive imaging of iron oxide nanoparticles as cellular contrast agents for optical coherence tomography

      Magnetomotive imaging of iron oxide nanoparticles as cellular contrast agents for optical coherence tomography

      Recent studies in animal models provided proof-of-principle evidence for cell transplantation as a potential future therapeutic approach for retinal pathologies in humans such as Retinitis pigmentosa or age-related macular degeneration. In this case, donor cells are injected into the eye in order to protect or replace degenerating photoreceptors or retinal pigment epithelium. However, currently there is no three-dimensional imaging technique available that allows tracking of cell migration and integration into the host tissue under in vivo conditions. Therefore, we investigate about magnetomotive optical coherence tomography (OCT) of substances labeled with iron oxide nanoparticles as a potential method for noninvasive, three-dimensional ...

      Read Full Article
    9. A new small-package super-continuum light source for optical coherence tomography

      A new small-package super-continuum light source for optical coherence tomography

      Broadband light sources provide a significant benefit for optical coherence tomography (OCT) imaging concerning the axial resolution. Light sources with bandwidths over 200 nm result in an axial resolution up to 2 microns. Such broad band OCT imaging can be achieved utilizing super continuum (SC) light sources. The main important disadvantage of commercial SC light sources is the overall size and the high costs. Therefore, the use of SC light sources in small OCT setups and applications is limited. We present a new small housing and costeffective light source, which is suitable for OCT imaging. The used light source has ...

      Read Full Article
    10. An advanced algorithm for dispersion encoded full range frequency domain optical coherence tomography

      An advanced algorithm for dispersion encoded full range frequency domain optical coherence tomography

      Dispersion encoded full range (DEFR) optical coherence tomography (OCT) has become highly attractive as it is a simple way to increase the measurement range of OCT systems. Full range OCT is especially favorable as it does not only increase the measurement range but also shifts the highest sensitivity into the center of the measurement range. While the early versions of DEFR were highly computational expensive, new versions reduce the number of necessary Fourier transforms. Recently it has been shown that a GPU based algorithm can perform DEFR with more than 20,000 A-lines per second. We present a new version ...

      Read Full Article
    11. Feature Of The Week 7/15/12: 3D Simultaneous Optical Coherence Tomography and Confocal Fluorescence Microscopy for Investigation of Lung Tissue

      Feature Of The Week 7/15/12: 3D Simultaneous Optical Coherence Tomography and Confocal Fluorescence Microscopy for Investigation of Lung Tissue

      The acute respiratory distress syndrome (ARDS) is a life-threatening condition of the lung leading to a state of decreased lung compliance and blood oxygenation efficiency. The treatment of patients utilizes artificial ventilation, which has a tremendous impact on the lung’s sensitive microenvironment and can even lead to further damage in the form of ventilator induced lung injury (VILI). As a basis for the understanding of physiological processes occurring on the microscale of lung tissue, the alveolar tissue, contact free imaging can elucidate dynamic changes during artificial ventilation. The main interest focuses here on the rearrangement of alveolar geometry and ...

      Read Full Article
    12. Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue

      Although several strategies exist for a minimal-invasive treatment of patients with lung failure, the mortality rate of acute respiratory distress syndrome still reaches 30% at minimum. This striking number indicates the necessity of understanding lung dynamics on an alveolar level. To investigate the dynamical behavior on a microscale, we used three-dimensional geometrical and functional imaging to observe tissue parameters including alveolar size and length of embedded elastic fibers during ventilation. We established a combined optical coherence tomography (OCT) and confocal fluorescence microscopy system that is able to monitor the distension of alveolar tissue and elastin fibers simultaneously within three dimensions ...

      Read Full Article
    13. Endoscopic optical coherence tomography device for forward imaging with broad field of view

      Endoscopic optical coherence tomography device for forward imaging with broad field of view

      One current challenge of studying human tympanic membranes (TM) with optical coherence tomography (OCT) is the implementation of optics that avoid direct contact with the inflamed tissue. At the moment, no commercial device is available. We report an optics design for contactless forward imaging endoscopic optical coherence tomography (EOCT) with a large working distance (WD) and a broad field of view (FOV) by restricting the overall diameter of the probe to be small (3.5 mm), ensuring a sufficient numerical aperture. Our system uses a gradient-index (GRIN) relay lens and a GRIN objective lens, and executes a fan-shaped optical scanning ...

      Read Full Article
    14. Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      Multimodal imaging of lung tissue using optical coherence tomography and two photon microscopy

      In the context of protective artificial ventilation strategies for patients with severe lung diseases, the contribution of ventilator settings to tissue changes on the alveolar level of the lung is still a question under debate. To understand the impact of respiratory settings as well as the dynamic process of respiration, high-resolution monitoring and visualization of the dynamics of lung alveoli are essential. An instrument allowing 3D imaging of lung tissue as well as imaging of functional constituents, such as elastin fibers, in in situ experimental conditions is presented in this study using a combination of Fourier domain optical coherence tomography ...

      Read Full Article
    15. Shear flow-induced optical inhomogeneity of blood assessed in vivo and in vitro by spectral domain optical coherence tomography in the 1.3 um wavelength range

      Shear flow-induced optical inhomogeneity of blood assessed in vivo and in vitro by spectral domain optical coherence tomography in the 1.3 um wavelength range

      The optical inhomogeneity of flowing blood, which appears as a waisted double fan-shaped intensity pattern inside vessels in cross-sectional optical coherence tomography (OCT) images, was investigated for the first time. High resolution spectral domain OCT in the 1.3 μm wavelength region is used to assess this inhomogeneous intravascular backscattering of light in an in vivo mouse model and flow phantom measurements. Based on a predicted alignment of the red blood cells toward laminar shear flow, an angular modulation of the corresponding backscattering cross-section inside the vessels is assumed. In combination with the signal attenuation in depth by absorption and ...

      Read Full Article
    16. Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy

      In critical care medicine, artificial ventilation is a life saving tool providing sufficient blood oxygenation to patients suffering from respiratory failure. Essential for their survival is the use of protective ventilation strategies to prevent further lung damage due to ventilator induced lung injury (VILI). Since there is only little known about implications of lung tissue overdistension on the alveolar level, especially in the case of diseased lungs, this research deals with the investigation of lung tissue deformation on a microscale. A combined setup utilizing optical coherence tomography (OCT) and confocal fluorescence microscopy, is used to study the elastic behavior of ...

      Read Full Article
    17. Axial resolution improvement by spectral data fusion in simultaneous dual-band optical coherence tomography

      Axial resolution improvement by spectral data fusion in simultaneous dual-band optical coherence tomography

      A method for axial resolution improvement by adequate spectral data fusion of two parallel acquired disjunct wavelength bands in the 0.8 μm and 1.3 μm region in the field of simultaneous dual-band optical coherence tomography (OCT) is presented. The applied spectral domain dual-band OCT system is illuminated by a supercontinuum laser light source and allows simultaneous imaging at 800 nm and 1250 nm with free-space axial resolutions better than 4.5 μm and 7 μm, respectively, over the entire depth scan range. Each wavelength band is analyzed with an individual spectrometer at an A-scan rate of 12 kHz ...

      Read Full Article
    18. Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography for imaging of subpleural alveolar structure using a Fourier domain mode locked laser

      Optical coherence tomography (OCT) is a noninvasive imaging modality generating cross sectional and volumetric images of translucent samples. In Fourier domain OCT (FD OCT), the depth profile is calculated by a fast Fourier transformation of the interference spectrum, providing speed and SNR advantage and thus making FD OCT well suitable in biomedical applications. The interference spectrum can be acquired spectrally resolved in spectral domain OCT or time-resolved in optical frequency domain imaging (OFDI). Since OCT images still suffer from motion artifacts, especially under in vivo conditions, increased depth scan rates are required. Therefor, the principle of Fourier domain mode locking ...

      Read Full Article
    19. Endoscopic optical coherence tomography for imaging the tympanic membrane

      Endoscopic optical coherence tomography for imaging the tympanic membrane

      Optical coherence tomography (OCT) is an imaging modality that enables micrometer-scale contactless subsurface imaging of biological tissue. Endoscopy, as another imaging method, has the potential of imaging tubular organs and cavities and therefore has opened up several application areas not accessible before. The combination of OCT and endoscopy uses the advantages of both methods and consequently allows additional imaging of structures beneath surfaces inside cavities. Currently, visual investigations on the surface of the human tympanic membrane are possible but only with expert eyes. up to now, visual imaging of the outer ear up to the tympanic membrane can be carried ...

      Read Full Article
    20. Optical coherence tomography in biomedical research

      Optical coherence tomography in biomedical research
      Optical coherence tomography (OCT) is a noninvasive, high-resolution, interferometric imaging modality using near-infrared light to acquire cross-sections and three-dimensional images of the subsurface microstructure of biological specimens. Because of rapid improvement of the acquisition speed and axial resolution of OCT over recent years, OCT is becoming increasingly attractive for applications in biomedical research. Therefore, OCT is no longer used solely for structural investigations of biological samples but also for functional examination, making it potentially useful in bioanalytical science. The combination of in vivo structural and functional findings makes it possible to obtain thorough knowledge on basic physiological and pathological processes ...
      Read Full Article
    21. Non-invasive imaging and monitoring of rodent retina using simultaneous dual-band optical coherence tomography

      Non-invasive imaging and monitoring of rodent retina using simultaneous dual-band optical coherence tomography

      Spectral domain dual-band optical coherence tomography for simultaneous imaging of rodent retina in the 0.8 μm and 1.3 μm wavelength region and non-invasive monitoring of the posterior eye microstructure in the field of retinal degeneration research is demonstrated. The system is illuminated by a supercontinuum laser source and allows three-dimensional imaging with high axial resolution better than 3.8 μm and 5.3 μm in tissue at 800 nm and 1250 nm, respectively, for precise retinal thickness measurements. A fan-shaped scanning pattern with the pivot point close to the eye's pupil and a contact lens are applied ...

      Read Full Article
    22. Three-dimensional functional imaging of lung parenchyma using optical coherence tomography combined with confocal fluorescence microscopy

      Three-dimensional functional imaging of lung parenchyma using optical coherence tomography combined with confocal fluorescence microscopy

      Optical coherence tomography (OCT), as a non-invasive technique for studying tissue morphology, is widely used in in vivo studies, requiring high resolution and fast three-dimensional imaging. Based on light scattering it reveals micrometer sized substructures of the samples due to changes in their optical properties and therefore allows quantification of the specimen's geometry. Utilizing fluorescence microscopy further information can be obtained from molecular compositions embedded in the investigated object. Fluorescent markers, specifically binding to the substance of interest, reveal the sample's chemical structure and give rise to functional studies. This research presents the application of a combined OCT ...

      Read Full Article
    23. Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue

      Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue

      Optical coherence tomography (OCT) is a technique, capable of high resolution and non-invasive 3D imaging in vivo by detection of backscattered light from cellular and sub cellular structures. Due to visualization of micrometer sized tissue constituents and high penetration depths of up to 2 mm, it is already well established in medical fields like ophthalmology and dermatology. Laser scanning confocal microscopy (LSCM), on the contrary, gives further information on structural tissue components stained with suitable dyes. In combination, these two methods yield three dimensional and high resolution data providing geometrical and structural details of tissue. In this study, we present ...

      Read Full Article
    24. Minimal invasive localization of the germinal disc in ovo for subsequent chicken sexing using optical coherence tomography

      Minimal invasive localization of the germinal disc in ovo for subsequent chicken sexing using optical coherence tomography

      Reason for using optical coherence tomography (OCT) to locate the germinal disc is the questionable and ethically alarming killing of male layer chickens because for the layer line only the females are necessary. To avoid this and to protect the animal rights, the sex of the fertilized chicken egg has to be determined as early as possible in the unincubated state. Because the information whether the chick becomes male or female can be found in the germinal disc an accurate localization for sexing is essential. The germinal disc is located somewhere on top of the yolk and has a diameter ...

      Read Full Article
    1-24 of 27 1 2 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (27 articles) Dresden University of Technology
    2. (27 articles) Edmund Koch
    3. (26 articles) Peter Cimalla
    4. (15 articles) Maria Gaertner
    5. (13 articles) Julia Walther
    6. (9 articles) Sven Meissner
    7. (3 articles) University of Toronto
    8. (3 articles) Lars Kirsten
    9. (1 articles) Henning Morawietz
    10. (1 articles) NKT Photonics
    11. (1 articles) New York Eye and Ear Infirmary
  3. Popular Articles

  4. Picture Gallery

    Simultaneous dual-band optical coherence tomography in the spectral domain for high resolution in vivo imaging Investigations of the intravascular backscattering distribution of light in optical coherence tomography Minimal invasive localization of the germinal disc in ovo for subsequent chicken sexing using optical coherence tomography Combining optical coherence tomography with fluorescence microscopy: a closer look into tissue Non-invasive imaging and monitoring of rodent retina using simultaneous dual-band optical coherence tomography Optical coherence tomography in biomedical research Endoscopic optical coherence tomography for imaging the tympanic membrane Investigation of alveolar tissue deformations using OCT combined with fluorescence microscopy Three-dimensional simultaneous optical coherence tomography and confocal fluorescence microscopy for investigation of lung tissue Feature Of The Week 7/15/12: 3D Simultaneous Optical Coherence Tomography and Confocal Fluorescence Microscopy for Investigation of Lung Tissue Retinal Vascular Features in Ocular Blunt Trauma by Optical Coherence Tomography Angiography Non-invasive imaging of a choroidal macrovessel