A technique to reposition sinotubular junction in aortic valve reimplantation procedures with the De Paulis Valsalva graft

n/

Can Nanotechnology Shine a New Light on Antimicrobial Photodynamic Therapies?

Recent developments in light‐controlled therapies (e.g., photodynamic and photothermal therapies) provide promising strategies to prevent and suppress bacterial infections, which are a leading cause of morbidity and mortality. Antibacterial photodynamic therapy (aPDT) has drawn increasing attention from the scientific society for its potential to kill multidrug‐resistant pathogenic bacteria and for its low tendency to induce drug resistance. In this chapter, we summarize the mechanism of action of aPDT, the photosensitizers, as well the current developments in terms of treating Gram‐positive and Gram‐negative bacteria. The chapter also describes the recent progress relating to photomedicine for preventing bacterial infections and biofilm formation. We focus on the laser device used in aPDT and on the light‐treatment parameters that may have a strong impact on the results of aPDT experiments. In the last part of this chapter, we survey on the various nanoparticles delivering photoactive molecules, and photoactive‐nanoparticles that can potentially enhance the antimicrobial action of aPDT

Anomalous origin of the left main artery from the pulmonary artery: Adult presentation with systemic collateral supply and giant right coronary artery aneurysm

n/

The double-orifice technique for mitral valve reconstruction: predictors of postoperative outcome

n/

Nonlinear properties of AlGaAs waveguides in continuous wave operation regime

Aluminum Gallium Arsenide (AlGaAs) is an attractive platform for the development of integrated optical circuits for all-optical signal processing thanks to its large nonlinear coefficients in the 1.55-μm telecommunication spectral region. In this paper we discuss the results of the nonlinear continuous-wave optical characterization of AlGaAs waveguides at a wavelength of 1.55 μm. We also report the highest value ever reported in the literature for the real part of the nonlinear coefficient in this material (Re(γ) ≈521 W<sup>−1</sup>m<sup>−1</sup>)

Impact of waveguide cross section on nonlinear impairments in integrated optical filters for WDM communication systems

Integrated optical chips enabling the realization of low-cost optical network units (ONU) is of great interest both for data centre solutions and for passive optical networks. In particular, in the frame of passive optical networks an interesting possibility is constituted by the presence, in the ONU of a Wavelength Division Multiplexing (WDM) filter [1] One of the most popular solution is based on a micro-ring resonators. The filter doesn’t introduce any relevant impairment in the downstream signal, as the optical power reaching the ONU, at the resonant wavelength, is generally so small that nonlinear effects can be generally neglected. Nevertheless, if the upstream signal, that generally has a much higher power, has to pass through the same resonator can undergo nonlinear effects like two-photon absorption (TPA), free-carriers absorption (FCA), and free-carrier dispersion (FCD) [2]. In this abstract we show the results of an experimental analysis we carried out in order to investigate the impact of optical nonlinear effects in WDM integrated micro-filters exploiting different designs (double- and triple- resonators structures, racetracks, rings, curved coupling regions, etc.) and exhibiting significantly different waveguide cross-sections (from 500 × 220 nm to 825 × 100 nm). The nonlinear behaviour evaluation has been carried out by performing two different sets of experiments. In the first one the amplified spontaneous emission emitted by an Er-doped fiber amplifier was filtered (by using a tunable filter with 5 nm band-width) and then amplified and then input by grating-assisted coupling to the filtering structures. Changes of filter transfer function were observed as a function of the input power. Conversely, in the second setup a narrowband CW-laser was used, and the behaviour of output power as a function of the input power was recorded

Soft proton exchanged channel waveguides in congruent lithium tantalate for frequency doubling

We report on stable optical waveguides fabricated by soft-proton exchange in periodically-poled congruent lithium tantalate in the α-phase. The channel waveguides are characterized in the telecom wavelength range in terms of both linear properties and frequency doubling. The measurements yield a nonlinear coefficient of about 9.5pm/V, demonstrating that the nonlinear optical properties of lithium tantalate are left nearly unaltered by the process

Viscoelasticity measurements by an optofluidic micro-rheometer

During the last decades, microrheology attracted a significant attention thanks to the possibility of investigating the viscoelastic properties of complex systems (e.g. cells and soft materials) at micrometer scale. The inherent low-consumption of sample offered by microrheology makes it the ideal candidate to study the rheological properties of precious/limited materials. In active microrheology, optical or magnetic forces enable trapping and manipulation of micro-probes in the fluid under test. The probe's response to external stimuli is used to derive the rheological properties of the surrounding medium. While this approach has been already reported in the scientific literature mainly using optical tweezers [1], in this document we propose a different system configuration based on a dual beam laser trap, previously exploited to realize a simple viscometer [2,3]. The here proposed device has all the features of a rheometer, also allowing to measure the elastic properties, and has the advantage of requiring a lower beam intensity while being able to apply larger forces with respect to standard optical tweezers. Additionally the system can be easily integrated in a glass substrate, requiring just an external connection to a CW-laser source and a low-magnification objective for sample observation