George Filippidis

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Elucidation of the molecular mechanisms regulating lipid storage and metabolism is essential for mitigating excess adiposity and obesity, which has been associated with increased prevalence of severe pathological conditions such as cardiovascular disorders and type II diabetes, worldwide. However, imaging fatty acid distribution and dynamics in vivo, at the(More)
In this study, we use combined two-photon excitation fluorescence (TPEF), second-harmonic generation (SHG) and third-harmonic generation (THG) measurements to image cellular structures of the nematode Caenorhabditis elegans, in vivo. To our knowledge, this is the first time that a THG modality is employed to image live C. elegans specimens. Femtosecond(More)
We report the fabrication of three-dimensional structures of submicrometer resolution by three-photon polymerization. This resolution has been achieved by polymerizing ORMOCER, a UV photocurable organic-inorganic hybrid material, with an ultrafast laser irradiation at 1028 nm. To our knowledge, this is the first demonstration of three-photon polymerization,(More)
In this study, neurodegeneration phenomena were investigated, by performing third harmonic generation imaging measurements on the nematode Caenorhabditis elegans, in vivo. The in vivo, precise identification of the contour of the degenerating neurons in the posterior part of the nematode and the monitoring, in real time, of the progression of degeneration(More)
Embryo patterning is subject to intense investigation. So far only large, microscopically obvious structures like polar body, cleavage furrow, pro-nucleus shape can be evaluated in the intact embryo. Using non-linear microscopic techniques, the present work describes new methodologies to evaluate pre-implantation mouse embryo patterning. Third Harmonic(More)
The identification of the state of human peripheral vascular tissue by using artificial neural networks is discussed in this paper. Two different laser emission lines (He-Cd, Ar+) are used to excite the chromophores of tissue samples. The fluorescence spectrum obtained, is passed through a nonlinear filter based on a high-order (HO) neural network neural(More)
Second-harmonic generation (SHG) and two-photon excitation fluorescence (TPEF) are relatively new and promising tools for the detailed imaging of biological samples and processes at the microscopic level. By exploiting these nonlinear phenomena phototoxicity and photobleaching effects on the specimens are reduced dramatically. The main target of this work(More)
We present the detailed imaging of structures and processes of the nematode Caenorhabditis elegans (C. elegans) using non-linear microscopy. Complementary information about the anatomy of the nematode was collected by implementing a combination of two photon excitation fluorescence (TPEF), second and third harmonic generation (SHG and THG) image contrast(More)
OBJECTIVE The fluorescence of tissue when stimulated by a laser beam is a well-known phenomenon. The resulting emission spectra depend on the biochemical and structural composition of the tissue. In this study, we examined the spectra of laser-induced fluorescence emitted by myocardial tissue. METHODS We used an argon-ion laser to stimulate the myocardium(More)
One of the main goals in optical characterization of biopsies is to discern between tissue types. Usually, the theory used for deriving the optical properties of such highly scattering media is based on the diffusion approximation. However, biopsies are usually small in size compared to the transport mean free path and thus cannot be treated with standard(More)