Publications de l’unité
Année de publication : 2018
Oxazole dyes with potential for photoluminescence bioprobes: A two-Photon absorption studyThe Journal of Physical Chemistry C : Just accepted manuscript : DOI : 10.1021/acs.jpcc.8b01904 En savoir plus
In this work, six π-conjugated oxazole compounds dissolved in dichloromethane (DCM) were characterized with linear and nonlinear optical measurements. Z-Scan with femtosecond laser pulses was employed to determine the two-photon absorption (TPA) spectra. Other photophysical parameters, such as: absorbance, solvatochromism, lifetime fluorescence and fluorescence anisotropy were evaluated with linear optical techniques. The experimental TPA cross-section spectra were adjusted by Sum-Over-States (SOS) model, in which important parameters such as transition dipole moments and broadening parameters were determined. In order to better understand the TPA spectra of the oxazole compounds, quantum-chemical calculations using the response function formalism and the DFT level of theory were performed. Using the results provided by the quantum-chemical calculations and the broadening parameters estimated through the application of the SOS model, the TPA spectra were simulated by the superposition (summation) of individual homogeneous Lorentzian absorption profiles.Replier
Iterative Variance Stabilizing Transformation Denoising of Spectral Domain Optical Coherence Tomography Images Applied to Retinoblastoma.Ophthalmic research : 59 : 164-169 : DOI : 10.1159/000486283 En savoir plus
BACKGROUND: Due to the presence of speckle Poisson noise, the interpretation of spectral domain-optical coherence tomography (SD-OCT) images frequently requires the use of data averaging to improve the signal-to-noise ratio. This implies long acquisition times and requires patient sedation in some cases. Iterative variance stabilizing transformation (VST) is a possible approach by which to remove speckle Poisson noise on single images.
METHODS: We used SD-OCT images of human and murine (LH Beta-Tag mouse model) retinas with and without retinoblastoma acquired with 2 different imaging devices (Bioptigen and Micron IV). These images were processed using a denoising workflow implemented in Matlab.
RESULTS: We demonstrated the presence of speckle Poisson noise, which can be removed by a VST-based approach. This approach is robust as it works in all used imaging devices and in both human and mouse retinas, independently of the tumor status. The implemented algorithm is freely available from the authors on demand.
CONCLUSIONS: On a single denoised image, the proposed method provides results similar to those expected from the SD-OCT averaging. Because of the friendly user interface, it can be easily used by clinicians and researchers in ophthalmology.Replier
NRL and CRX Define Photoreceptor Identity and Reveal Subgroup-Specific Dependencies in MedulloblastomaCancer Cell : 33 : 435-449 : DOI : 10.1016/j.ccell.2018.02.006 En savoir plus
Cancer cells often express differentiation programs unrelated to their tissue of origin, although the contribution of these aberrant phenotypes to malignancy is poorly understood. An aggressive subgroup of medulloblastoma, a malignant pediatric brain tumor of the cerebellum, expresses a photoreceptor differentiation program normally expressed in the retina. We establish that two photoreceptor-specific transcription factors, NRL and CRX, are master regulators of this program and are required for tumor maintenance in this subgroup. Beyond photoreceptor lineage genes, we identify BCL-XL as a key transcriptional target of NRL and provide evidence substantiating anti-BCL therapy as a rational treatment opportunity for select MB patients. Our results highlight the utility of studying aberrant differentiation programs in cancer and their potential as selective therapeutic vulnerabilities.Replier