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- Ilagan, R P, et al.
(author)
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Femtosecond time-resolved absorption spectroscopy of astaxanthin in solution and in alpha-crustacyanin
- 2005
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In: The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory. - : American Chemical Society (ACS). - 1520-5215. ; 109:14, s. 3120-3127
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Journal article (peer-reviewed)abstract
- Steady-state absorption and femtosecond time-resolved spectroscopic studies have been carried out on astaxanthin dissolved in CS2, methanol, and acetonitrile, and in purified alpha-crustacyanin. The spectra of the S-0 -> S-2 and S-1 -> S-n transitions were found to be similarly dependent on solvent environment. The dynamics of the excited-state decay processes were analyzed with both single wavelength and global fitting procedures. In solution, the S-1 lifetime of astaxanthin was found to be similar to 5 ps and independent of solvent. In alpha-crustacyanin, the lifetime was noticeably shorter at similar to 1.8 ps. Both fitting procedures led to the conclusion that the lifetime of the S-2 state was either comparable to or shorter than the instrument response time. The data support the idea that dimerization of astaxanthin in alpha-crustacyanin is the primary molecular basis for the bathochromic shift of the S-0 -> S-2 and S-1 - S-n transitions. Planarization of the astaxanthin molecule, which leads to a longer effective pi-electron conjugated chain and a lower S-1 energy, accounts for the shorter tau(1) in the protein.
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4. |
- Jansson, T, et al.
(author)
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Automated correction of linear deformation due to sectioning in serial micrographs.
- 1995
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In: Journal of microscopy. - 0022-2720. ; 177:Pt 2, s. 119-27
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Journal article (peer-reviewed)abstract
- This paper describes an objective and automatic method for detection and correction of sectioning deformations in digitized micrographs, as well as an evaluation of the method applied to light and electron microscopic images of semi-thin and ultra-thin serial sections from brain cortex. The detection is based on matching of image subregions and the deformation model is bi-linear, i.e. two first-order polynomials are used for modelling compression/expansion in perpendicular directions. The procedure is applicable to prealigned serial two-dimensional sections and is primarily aimed at three-dimensional reconstruction of tissue samples consisting of a large number of cells with random distribution and morphology.
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6. |
- Knigge, U., et al.
(author)
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ENETS Consensus Recommendations for the Standards of Care in Neuroendocrine Neoplasms : Follow-Up and Documentation
- 2017
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In: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 105:3, s. 310-319
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Journal article (peer-reviewed)abstract
- ENETS consensus recommendations for the standards of care in neuroendocrine neoplasms (NEN) concerning follow-up and documentation are considered in this review. The documentation of patients with NEN should include the most relevant data characterizing an individual patient from the first contact with his/her physician/hospital until his/her last presentation during follow-up. It is advocated that follow-up occurs in specialized NEN centers with regular NEN tumor boards with expert panels. The follow-up should be in accordance with the ENETS consensus guidelines from 2011 and 2016, the present and coming WHO classification and ENETS/UICC recommendations for TNM staging. The recommendations for follow-up in patients with thymic, bronchopulmonary and gastroenteropancreatic NEN are given in Table 1. However, it should be stressed that evidence-based studies for follow-up are largely missing.
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8. |
- Meyer, Tobias, et al.
(author)
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A compact microscope setup for multimodal nonlinear imaging in clinics and its application to disease diagnostics
- 2013
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In: Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528. ; 138:14, s. 4048-4057
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Journal article (peer-reviewed)abstract
- The past years have seen increasing interest in nonlinear optical microscopic imaging approaches for the investigation of diseases due to the method's unique capabilities of deep tissue penetration, 3D sectioning and molecular contrast. Its application in clinical routine diagnostics, however, is hampered by large and costly equipment requiring trained staff and regular maintenance, hence it has not yet matured to a reliable tool for application in clinics. In this contribution implementing a novel compact fiber laser system into a tailored designed laser scanning microscope results in a small footprint easy to use multimodal imaging platform enabling simultaneously highly efficient generation and acquisition of second harmonic generation (SHG), two-photon excited fluorescence (TPEF) as well as coherent anti-Stokes Raman scattering (CARS) signals with optimized CARS contrast for lipid imaging for label-free investigation of tissue samples. The instrument combining a laser source and a microscope features a unique combination of the highest NIR transmission and a fourfold enlarged field of view suited for investigating large tissue specimens. Despite its small size and turnkey operation rendering daily alignment dispensable the system provides the highest flexibility, an imaging speed of 1 megapixel per second and diffraction limited spatial resolution. This is illustrated by imaging samples of squamous cell carcinoma of the head and neck (HNSCC) and an animal model of atherosclerosis allowing for a complete characterization of the tissue composition and morphology, i.e. the tissue's morphochemistry. Highly valuable information for clinical diagnostics, e. g. monitoring the disease progression at the cellular level with molecular specificity, can be retrieved. Future combination with microscopic probes for in vivo imaging or even implementation in endoscopes will allow for in vivo grading of HNSCC and characterization of plaque deposits towards the detection of high risk plaques.
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9. |
- Meyer, Tobias, et al.
(author)
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Expanding Multimodal Microscopy by High Spectral Resolution Coherent Anti-Stokes Raman Scattering Imaging for Clinical Disease Diagnostics
- 2013
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 1520-6882 .- 0003-2700. ; 85:14, s. 6703-6715
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Journal article (peer-reviewed)abstract
- Over the past years fast label-free nonlinear imaging modalities providing molecular contrast of endogenous disease markers with subcellular spatial resolution have been emerged. However, applications of these imaging modalities in clinical settings are still at the very beginning. This is because single nonlinear imaging modalities such as second-harmonic generation (SHG) and two-photon excited fluorescence (TPEF) have only limited value for diagnosing diseases due to the small number of endogenous markers. Coherent anti-Stokes Raman scattering (CARS) microscopy on the other hand can potentially be added to SHG and TPEF to visualize a much broader range of marker molecules. However, CARS requires a second synchronized laser source and the detection of a certain wavenumber range of the vibrational spectrum to differentiate multiple molecules, which results in increased experimental complexity and often inefficient excitation of SHG and TPEF signals. Here we report the application of a novel near-infrared (NIR) fiber laser of 1 MHz repetition rate, 65 ps pulse duration, and 1 cm(-1) spectral resolution to realize an efficient but experimentally simple SGH/TPEF/multiplex CARS multimodal imaging approach for a label-free characterization of composition of complex tissue samples. This is demonstrated for arterial tissue specimens demonstrating differentiation of elastic fibers, triglycerides, collagen, myelin, cellular cytoplasm, and lipid droplets by analyzing the CARS spectra within the C-H stretching region only. A novel image analysis approach for multispectral CARS data based on colocalization allows correlating spectrally distinct pixels to morphologic structures. Transfer of this highly precise but compact and simple to use imaging approach into clinical settings is expected in the near future.
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10. |
- Pascher, R, et al.
(author)
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Computer-assisted 3D analysis of cell distributions in the normal and epileptic cerebral cortex: description of a methodology in progress.
- 1993
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In: Computerized medical imaging and graphics : the official journal of the Computerized Medical Imaging Society. - 0895-6111. ; 17:4-5, s. 405-10
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Journal article (peer-reviewed)abstract
- This paper describes software routines that (a) visualizes a stack of several thousands of aligned sequential photographic two-dimensional (2D) images stored in an image processing system; (b) creates a data base containing information about objects identified sequentially from the 2D images; (c) transfers the data base to a graphical terminal; (d) reconstructs a three-dimensional (3D) object space; and (e) supports on-line interaction between the image processing system and the graphical terminal. As an application example, the cell content of a prism of motor cerebral cortex of the cat is reconstructed. Preliminary results from reconstructing human epileptic temporal cortex (cortical microdysgenesia) are also reported.
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