The quantum efficiency and the molar-absorption coefficients of different phenothiazine dyes are obtained by means of fitting the experimental data of transmittance as a function of time. An analytical expression for the intensity transmitted in a photopolymerizable holographic material is obtained, and good agreement between theory and experience is also achieved. The analysis of these parameters is of fundamental quantities in the photochemical characterization of holographic recording materials.
BackgroundDystrophic Epidermolysis Bullosa (DEB) is a rare genodermatosis (7 cases per million) that causes blisters and erosions with minor trauma in skin and mucosa, and other systemic complications. A recently updated systematic review showed that the research evidence about DEB therapies is poor. As new trials in DEB are difficult and expensive, it is important to prioritizise research that patients and clinicians consider more relevant.ObjectivesTo describe and prioritize the most important uncertainties about DEB treatment shared by patients, carers and health care professionals (HCPs) in order to promote research in those areas.MethodsA DEB Priority Setting Partnership (PSP) was established, including patients, carers and HCPs. DBE uncertainties were gathered from patients and clinicians, and prioritized in a transparent process, using the methodology advocated by the James Lind Alliance.ResultsIn the consultation stage, 323 uncertainties were submitted by 58 participants. Once the duplicated and non-treatment uncertainties were removed, the remainder were reduced to a list of 24 most voted questions. These 24 uncertainties were prioritized in a final workshop where a balanced number of patients, carers and HCPs selected the top 10 therapy uncertainties. The final list includes interventions in wound care, itch and pain management, treatment and prevention of syndactyly, cancer prevention and future promising therapies.ConclusionsThe final list of the top 10 treatment uncertainties on the management of DEB provides guidance for researchers and funding bodies, to ensure that future research answers questions that are important to both clinicians and patients. The method proposed by the James Lind Alliance is feasible for very rare disorders.
A study of the optimization and the characteristics of a dry film photopolymerizable recording material is presented. The effects of intensity, the thickness, and the variation of the concentration of each component have been studied. Diffraction efficiencies of 80%, with energetic sensitivities of 40 mJ/cm(2), have been obtained in photosensitive films of a 35-mum thickness with a spatial frequency of 1000 lines/mm.
We theoretically analyze Airy beams by solving the exact vectorial Helmholtz equation using boundary conditions at a diffraction aperture. As result, the diffracted beams are obtained in the whole space; thus, we demonstrate that the parabolic trajectories are larger than those previously reported, showing that the Airy beams start to form before the Fourier plane. We also demonstrate the possibility of using a new type of Airy beams (SAiry beams) with finite energy that can be generated at the focal plane of the lens due to diffraction by a circular aperture of a spherical wave modified by a cubic phase. The finite energy ensured by the principle of conservation of energy of a diffracted beam.
A matrix method which relates the field and its derivative is presented for the study of wave propagation in any type of one-dimensional media. The transfer matrix is obtained from the canonical solutions of Helmholtz equations at normal incidence. The method is applied to different optical systems like a Fabry-Perot cavity formed by uniform fiber Bragg gratings, periodic dielectric structures and different quasi-periodic structures based on Fibonacci and Thue-Morse sequences of layers with constant and variable refractive index.
A photopolymerizable holographic material has been obtained and characterized using agent N,N′-dihydroxiethylenbisacrylamide as crosslinking. A sensitivity of 5 mJ/cm2 and a diffraction efficiency around of 70% have been reached for holograms recorded at 633 nm with a spatial frequency of 1000 lines/mm. High sensitivities can be obtained with low intensities, and this is important in applications such as holographic interferometry and the fabrication of holographic optical elements.
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