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The paper presents a successful, simple method for the preparation and deposition of new hybrid Cu-doped ZnO/microcellulose coatings on textile fibers, directly from cellulose aqueous solution. The morphological, compositional, and structural properties of the obtained materials were investigated using different characterization methods, such as SEM-EDX, XRD, Raman and FTIR, as well as BET surface area measurements. The successful doping of ZnO NPs with Cu was confirmed by the EDX and Raman analysis. As a result of Cu doping, the hybrid NPs experienced a phase change from ZnO to (Zn0.9Cu0.1)O, as shown by the XRD results. All the hybrid NPs exhibited a high degree of crystallinity, as revealed by the very sharp reflections in XRD patterns and suggested also by the Raman results. The evaluation of the very low copper-doping (0.1-1 at.%) effect has shown different behavior trends of the hybrid coatings compared with the starting oxide NPs, for MB and MO photodegradation. Continuous increases up to 92% and 60% for MB and MO degradation, respectively, were obtained at maximum 1 at.%-Cu doping coatings. Strong antibacterial activity against S. aureus and E. coli were observed.
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We discuss distributed chemical sensing based on the swelling of coatings of optical fibers. Volume changes in the coating induce strain in the fiber's glass core, provoking a local change in the refractive index which is detectable by distributed fiber optical sensing techniques. We describe methods to realize different coatings on a single fiber. Simultaneous detection of swelling processes all along the fiber opens the possibility to interrogate thousands of differently functionalized sections on a single fiber. Principal component analysis is used to enable sensors for environmental monitoring, food analysis, agriculture, water quality monitoring, or medical diagnostics.
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Distributed chemical sensing is demonstrated using standard acrylate coated optical fibers. Swelling of the polymer coating induces strain in the fiber's silica core provoking a local refractive index change which is detectable all along an optical fiber by advanced distributed sensing techniques. Thermal effects can be discriminated from strain using uncoated fiber segments, leading to more accurate strain readings. The concept has been validated by measuring strain responses of various aqueous and organic solvents and different chain length alkanes and blends thereof. Although demonstrated on a short range of two meters using optical frequency-domain reflectometry, the technique can be applied to many kilometer-long fiber installations. Low-cost and insensitive to corrosion and electromagnetic radiation, along with the possibility to interrogate thousands of independent measurement points along a single optical fiber, this novel technique is likely to find applications in environmental monitoring, food analysis, agriculture, water quality monitoring, or medical diagnostics.
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Abstract: The present study aimed to assess the eighteen month follow-up patient-centered outcomes of a simple and predictable protocol for 3D-printed functional complete dentures manufactured using an improved poly(methyl methacrylate) (PMMA)-nanoTiO2. A detailed morphological and structural characterization of the PMMA-TiO2 nanocomposite, using SEM, EDX, XRD, and AFM, after 3D-printing procedure and post-wearing micro-CT, was also performed. METHODS: A total of 35 fully edentulous patients were enrolled in this prospective study. A 0.4% TiO2-nanoparticle-reinforced PMMA composite with improved mechanical strength, morphologically and structurally characterized, was used according to an additive computer-aided design and computer-aided manufacturing (CAD/CAM) protocol for complete denture fabrication. The protocol proposed involved a three-step appointment process. Before denture insertion, 1 week, 12 month, and 18-month follow up patients were evaluated via the Visual Analogue Scale (VAS, 0-10) and Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT), with a higher score meaning poor quality of life. RESULTS: A total of 45 complete denture sets were inserted. OHIP-EDENT scored significantly better after 18 months of denture wearing, 20.43 (±4.42) compared to 52.57 (±8.16) before treatment; mean VAS was improved for all parameters assessed. CONCLUSIONS: Within the limitations of this study, we can state that the proposed workflow with the improved material used is a viable treatment option for patients diagnosed with complete edentulism.
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A high-order polynomial fitting method is proposed to accelerate the computation of double-Gaussian fitting in the retrieval of the Brillouin frequency shifts (BFS) in optical fibers showing two local Brillouin peaks. The method is experimentally validated in a distributed Brillouin sensor under different signal-to noise ratios and realistic spectral scenarios. Results verify that a sixth-order polynomial fitting can provide a reliable initial estimation of the dual local BFS values, which can be subsequently used as initial parameters of a nonlinear double-Gaussian fitting. The method demonstrates a 4.9-fold reduction in the number of iterations required by double-Gaussian fitting and a 3.4-fold improvement in processing time.
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Titanium dioxide exists in three crystalline phases: anatase, rutile and brookite. Although rutile is thermodynamically more stable, anatase is considered as the most favorable phase for photocatalysis and solar energy conversion. Recent studies have shown a significant improvement of light harvesting and overall solar conversion efficiency of anatase nanoparticles in dye-sensitized solar cells (DSSCs) when using a mixture of anatase and rutile phases (10-15% rutile). TiO2 nanopowders have been prepared by a solar physical vapor deposition process (SPVD). This method has been developed in Odeillo-Font Romeu France using "heliotron" solar reactors working under concentrated sunlight in 2 kW solar furnaces. By controlling reactor's atmosphere type (air/argon) and gas pressure, several types of anatase/rutile nanophases have been obtained with slightly different microstructural properties and morphological characteristics. X-ray diffraction analyses (XRD) were performed on precursor and on the SPVD obtained nanopowders. Information concerning their phase composition and coherence diffraction domain (crystallites size and strain) was obtained. Nanopowders morphology has been studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).