Hybrid inorganic/organic photonic crystal biochips for cancer biomarkers detection

We report on hybrid inorganic/organic one-dimensional photonic crystal biochips sustaining Bloch surface waves. The biochips were used, together with an optical platform operating in a label-free and fluorescence configuration simultaneously, to detect the cancer biomarker Angiopoietin 2 in a protein base buffer. The hybrid photonic crystals embed in their geometry a thin functionalization poly-acrylic acid layer deposited by plasma polymerization, which is used to immobilize a monoclonal antibody for highly specific biological recognition. The fluorescence operation mode is described in detail, putting into evidence the role of field enhancement and localization at the photonic crystal surface in the shaping and intensification of the angular fluorescence pattern. In the fluorescence operation mode, the hybrid biochips can attain the limit of detection 6 ng/ml.We report on hybrid inorganic/organic one-dimensional photonic crystal biochips sustaining Bloch surface waves. The biochips were used, together with an optical platform operating in a label-free and fluorescence configuration simultaneously, to detect the cancer biomarker Angiopoietin 2 in a protein base buffer. The hybrid photonic crystals embed in their geometry a thin functionalization poly-acrylic acid layer deposited by plasma polymerization, which is used to immobilize a monoclonal antibody for highly specific biological recognition. The fluorescence operation mode is described in detail, putting into evidence the role of field enhancement and localization at the photonic crystal surface in the shaping and intensification of the angular fluorescence pattern. In the fluorescence operation mode, the hybrid biochips can attain the limit of detection 6 ng/ml

Cavitation bubble wall pressure measurement by an electromagnetic surface wave enhanced pump-probe configuration

We report on the measurement of the pressure associated with a shock wave within a very thin layer (100 nm) in proximity of a boundarysurface. In the experiments, the shock wave was emitted by a cavitation bubble generated by a pulsed pump laser in water. We developed apump-probe setup based on the detection of the light scattered at the surface of a one-dimensional photonic crystal, which was purposelydesigned to sustain a surface electromagnetic wave in the visible range and to enhance the optical response. In order to better understand thephenomenon, we implemented numerical simulations to describe the light scattering intensity distributions through a modified Rayleigh’smethod. We report, with a LoD of about 0.1 MPa, the measurements of the pressure at a surface in the presence of a laser-induced cavitationbubble generated at different distances from the surface and for different pulse energies

Design rules for combined label-free and fluorescence Bloch surface wave biosensors

We report on the fabrication and physical characterization of optical biosensors implementing simultaneous label-free and fluorescence detection and taking advantage of the excitation of Bloch surface waves at a photonic crystal’s truncation interface. Two types of purposely-designed one dimensional photonic crystals on molded organic substrates with micro-optics were fabricated. These feature either high or low finesse of the Bloch surface wave resonances and were tested on the same optical readout system. The experimental results show that designing biochips with a large resonance quality factor does not necessarily lead in the real case to an improvement of the biosensor performance. Conditions for optimal biochips’ design and operation of the complete bio-sensing platform are established

Prediction of Void Fraction in PWR Subchannel by CATHARE2 Code

The current generation of thermal-hydraulic system codes benefits of about sixty years of experiments and forty years of development and are considered mature tools to provide best estimate description of phenomena and detailed reactor system representations. However, there are continuous needs for checking the code capabilities in representing nuclear system, in drawing attention to their weak points, in identifying models which need to be refined for best-estimate calculations. Prediction of void fraction and Departure from Nucleate Boiling (DNB) in system thermal-hydraulics is currently based on empirical approaches. The database carried out by Nuclear Power Engineering Corporation (NUPEC), Japan addresses these issues. It is suitable for supporting the development of new computational tools based on more mechanistic approaches (i.e. 3 field codes, 2 phase CFD, etc.) as well as for validating current generation of thermal-hydraulic system codes. Selected experiments belonging to this database are also used for the OECD/NRC PSBT benchmark. The paper presents the validation activity performed by CATHARE2 v2.5_1 (six equation, two field) code on the basis of the sub-channel experiments available in the database and performed in different test sections. Four sub-channel test sections are addressed in different thermal-hydraulic conditions (i.e. pressure, coolant temperature, mass flow and power). Sensitivity analyses are carried out addressing nodalization effect and the influence of the initial and boundary conditions of the tests

Method for thermal diffusivity measurements based on photothermal deflection

The thermal diffusivity measurement through pulsed photodeflection in a modified collinear configuration is presented and discussed; comparison between theory and experiment is also shown

Spectral analysis of organic LED emitters’ orientation in thin layers by resonant emission on dielectric stacks

Purposely tailored thin film stacks sustaining surface waves have been utilized to create a unique link between emission angle and wavelength of fluorescent dye molecules. The knowledge of the thin film stack’s properties allows us to derive the intrinsically emitted luminescence spectrum as well as to gain information about the orientation of fluorophores from angularly resolved experiments. This corresponds to replacing all the equipment necessary for polarized spectroscopy with a single smart thin film stack, potentially enabling single shot analyses in the future. The experimental results agree well with those from other established techniques, when analyzing the Rubrene derivative in a 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine (T2T) host used for the fabrication of optimized organic light-emitting diodes. The findings illustrate how resonant layered stacks can be applied to integrated spectroscopic analyses

Influence of Aeration Rate on Uncoupled Fed Mixed Microbial Cultures for Polyhydroxybutyrate Production

The use of residual streams as feedstock for the production of polyhydroxyalkanoates (PHAs) is growing steadily, as it allows the valorization of waste and nutrients otherwise disposed of and the potential production of a biodegradable bioplastic. To date, the environmental and economic costs associated with this process limit its scale-up, which is why it is important to identify possible solutions and optimize the costliest steps. With this in mind, a laboratory-scale sequenced batch reactor (SBR, 5 L) was constructed to allow the selection of a mixed microbial culture able to convert volatile fatty acids (VFAs) into PHA. The reactor is fed with synthetic water containing VFAs, ammonium, phosphate, and micronutrients, typical compounds of fermented streams of certain wastes, such as cheese whey, food waste, or wastewater sludge. The biomass selected and produced by this first reactor is sent to an accumulation reactor, which is fed with a solution rich in VFAs, allowing the accumulation of PHAs. The role of aeration and its impacts on the main process parameters were analyzed. Three scenarios corresponding to different aeration rates were analyzed: 0.08, 0.16, and 0.32 vvm. The SBR was operated at an organic load rate of 600 mgCOD L-1d-1, under a dynamic feeding regime (feast-famine) and a short hydraulic retention time (HRT; 1 day). The results obtained showed that a value of 0.32 enabled better selection and better settling of the sludge. Furthermore, a potential correlation between aeration rate and VFA and NH4+ consumption rates was identified. The resulting biomass was able to accumulate up to 0.15 +/- 0.02 g PHAgVSS-1

Laser Induced Breakdown and Bubble Cavitation

This work presents the results of an experimental investigation of laser induced cavitation. We find that the breakdown plasma can be randomly split in different branches depending on the laser energy and on the focusing angle. This behavior strongly affects the successive dynamics of the bubble and limits the reproducibility of the process. Using a custom fiber optic hydrophone, we correlate the elongated shape of the plasma with the number of shock waves detected at breakdown. The conditions for single breakdown shockwave emission and spherical expansion are thus identified, thus improving the reproducibility of the laser-induced cavitation bubble

Bloch surface waves-controlled fluorescence emission: coupling into nanometer-sized polymeric waveguides

The lateral confinement of Bloch surface waves on a patterned multilayer is investigated by means of leakage radiation microscopy (LRM). Arrays of nanometric polymeric waveguides are fabricated on a proper silicon-nitride/silicon-oxide multilayer grown on a standard glass coverslip. By exploiting the functional properties of the polymer, fluorescent proteins are grafted onto the waveguides. A fluorescence LRM analysis of both the direct and the Fourier image plane reveals that a substantial amount of emitted radiation couples into a guided mode and then propagates into the nanometric waveguide. The observations of the mode are supported by numerical simulations

Dye Solar Cells: Basic and Photon Management Strategies

Since the introduction and development of the dye-sensitized solar cell (DSC) several efforts have been made to optimize the materials involved in the photo-electrochemical process and to improve the light conversion efficiency of the device , by exploiting a low cost production process based on simple fabrication methods, similar to those used in printing processes