Diffusion Enhanced Upconversion in Organic Systems

The upconverted fluorescence generation in a solution of multicomponent organic systems has been studied as a function of the temperature to investigate the role of resonant energy transfer processes and of the molecular diffusion on the overall emission yield. The strong blue emission observed exciting the samples at 532 nm derives from a bimolecular triplet-triplet annihilation between 9,10 diphenylanthracene molecules, which produces singlet excited states from which the higher energy emission takes place. Diphenylanthracene excited triplet states are populated by energy transfer from a phosphorescent donor (Pt(II)octaethylporphyrin) which acts as excitation light harvesting. At low temperature, the experimental data on the efficiency of the transfer have been interpreted in the frame of a Dexter energy transfer in the Perrin approximation. At room temperature, the fast diffusion of the molecules has been found to be the main factor which affects the energy transfer rates and the overall photon upconversion efficiency

One Dimensional Polymeric Organic Photonic Crystals for DFB Lasers

We present a very simple method to realize a one-dimensional photonic crystal (1D PC), consisting of a dye-doped polymeric multilayer. Due to the high photonic density of states at the edges of the photonic band-gap (PBG), a surface emitting distributed feedback (DFB) laser is obtained with this structure. Furthermore, the incidence angle dependence of the PBG of the polymeric multilayer is reported

Is Parkinson's disease an unique clinical entity? Rigid or tremor dominant PD: Two faces of the same coin

Parkinson's disease is one of the most described neurodegenerative pathologies; though it is one of the most complex pathologies, is not fully understood, correctly identified, with its different types of presentation, its clinical course and the neural networks involved. We report on a series consisting of 432 de novo PD diagnosed patients, and 457 control cases. We identify a possible independent relationship between two clinical PD presentation, akinetic-rigid and tremor-dominant, and cognitive and behavioral changes. A 24-months follow-up allows to identify new information still not fully explored

Ring-resonator filters in silicon oxynitride technology for dense wavelenght-division multiplexing systems

The design and characterization of ring-resonator-based filters with free spectral ranges of 100 and 50 GHz by use of SiOxNy technology is presented. Fiber-to-fiber insertion losses of 4.4 dB on the drop port and 2.1 dB on the through port have been achieved for a single-ring filter. An interleaver filter for a 25-GHz spaced dense wavelength-division multiplexing system with two cascaded rings is demonstrated. The filter has a 7.4-GHz bandwidth at -1 dB and an extinction ratio of 15 dB and is polarization independent

Lasing in one dimensional dye-doped random multilayer

Lasing action in a fully organic dye doped flexible 1D random multilayer photonic crystal is reported. The emission energy can be modulated by varying layers thicknesses to fit the dye characteristics, thus showing the potential interest of such cheap materials in active devices for optoelectronic applications

Preservazione con collagene riassorbibile del sito postestrattivo prima del posizionamento di impianti a carico immediato in zone estetiche* Presentazione di un caso e valutazione istologica a 4 mesi

The membranes of barrier made by resorbable collagen proved suitable procedures for use in guided tissue regeneration (GTR) and like correction of anatomical defects.This article calls for the use of absorbable collagen plugs for use in extraction sockets to maintain the volumes of the bone ridge and allow the placement of implants in the frontal areas with better appearance. We explain how to use this material. To this end we presente the characteristics of the material and argue indications and contraindications. We show a case of practical application of these principles and the details of this technique. The objective of this study is to present a technique, that, used in appropriate cases, is easily applicable and allows to obtain better aesthetic result in the rehabilitation of immediate loading at the stage of provisional prosthesis