Experimental determination of shift-less aberration bases for sensorless adaptive optics in nonlinear microscopy.

Adaptive optics can improve the performance of optical systems and devices by correcting phase aberrations. While in most applications wavefront sensing is employed to drive the adaptive optics correction, some microscopy methods may require sensorless optimization of the wavefront. In these cases, the correction is performed by describing the aberration as a linear combination of a base of influence functions, optimizing an image quality metric as a function of the coefficients. The influence functions base is generally chosen to either efficiently represent the adaptive device used or to describe generic wavefronts in an orthogonal fashion. A rarely discussed problem is that most correction bases have elements which introduce, together with a correction of the aberration, a shift of the imaging field of view in three dimensions. While simple methods to solve the problem are available for linear microscopy methods, nonlinear microscopy techniques such as multiphoton or second harmonic generation microscopy require non-trivial base determination. In this paper, we discuss the problem, and we present a method for calibrating a shift-less base on a spatial light modulator for two-photon microscopy.

Effects of L-DOPA Pretreatment on the Kinetics, Migration and Carbon Ion Radiation Response of T98G Cells.

BACKGROUND/AIM: Glioblastoma is the most malignant and widespread brain tumor in adults, with a rapid clinical course. Recently, it has been hypothesized that L-DOPA plays a role in the diagnosis and treatment of glioblastoma. The aim of this study was to assess the effects of pretreatment with L-DOPA on the biological behavior of human T98G cells in vitro. MATERIALS AND METHODS: T98G cells were treated with 50 µg/ml or 100 µg/ml of L-DOPA for 4 h and their morphology, growth rate, clonogenic survival and migratory capacity in basal conditions and after carbon ion irradiation were evaluated using standard methods. RESULTS: Treated cells showed a lower growth rate and an increased migratory capacity that correlated with the dose of tested L-DOPA. Treatment with L-DOPA increased the growth rate of carbon ion irradiated T98G cells compared to control non-treated cells exposed to the same radiation dose. CONCLUSION: Our results open further questions about the overall advantage of L-DOPA treatment of glioblastoma.