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Ceramic materials based on mullite, cristobalite, and zircon phases prepared with different zinc and copper additions using the co-precipitation method and followed by calcination at 500 °C for 2 h are investigated. The effectiveness of these substrates against bacteria was tested against Gram-positive and Gram-negative pathogenic strains: Staphylococcus aureus, Bacillus subtilus, Escherichia coli, Pseudomonas putida,and Enterobacter aerogenes. The obtained nanoparticles with different crystal sizes were subjected to various types of characterization, including structural by X-ray diffraction (XRD), morphology by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) transmission electron microscopy (TEM), optical analysis by Raman spectroscopy. SEM images showed a change in the shape of the ceramic nanocomposites after adding zinc and copper to become similar to flake structures. This addition was detected by EDS analysis, where the first sample was found to contain 1.49 at.% Cu and 7.41 at.% Zn. The TEM image confirmed that the kaolin grains were in the form of nanotubes and were coated with spherical nanograins after adding ZrO2, Zn, and Cu. The newly developed ceramic compound, consisting of mullite–zircon–zinc oxide–copper oxide with a primary source, kaolin DD3, was found to be more effective than its predecessors. It gave unprecedented anti-activity for many types of bacteria (Gram-positive and Gram-negative). Given the shape flake-like of the new ceramic compound, it provides a wider effective area through micro-tubes to the granules. It has a high percentage of holes that allow bacteria to be attracted and placed inside. A maximum inhibition zone of 38.1 ± 0.1 mm was obtained with S. aureusfor DD3 + ZrO2/ZnO (28 wt.%)/CuO (2.8 wt.%), a zone of 29.2 ± 0.2 mm with P. putida; for DD3 + ZrO2/ZnO (14.28 wt.%)/CuO (5.37 wt.%) and an inhibition zone of 28.85 ± 0.15 mm was obtained with B. subtilisfor DD3 + ZrO2/ZnO (14.28 wt.%)/CuO (5.37 wt.%). The ceramic DD3 + 38% ZrO2possesses 33% of the holes, which represents the largest percentage in this compound and, therefore, is primarily responsible for the effect that occurs during biological application. All samples showed a high antibacterial activity, which increased with the addition of Zn:Cu and decreased with the increase in grain size. Ions and reactive oxygen species (ROS) release released into the cellular environment present a huge obstacle to dynamic membrane transport and lead to DNA damage and, ultimately, cell necrosis or apoptosis, which was effective for the inhibition of bacterial growth.

In this work we studied the effect of doping on heterogeneous photocatalysis application we used the samples CuO, 5% Ag:CuO, 15% Ag:CuO, 25% Ag:CuO and 50% Ag:CuO catalysts thin layers which were prepared by the sol gel method on a glass substrate. The structural, morphological, optical and electrical characteristics of these layers were studied by XRD, IR, SEM, UV-Vis spectrophotometry and four-point analysis. The results of the XRD, it is observed that the structure of the monoclinic phase develops, with preferential orientations following the plane (-111). This indicated that the thin films are polycrystalline, these results and confirmed by the IR spectra. In the case of Ag doping the SEM revealed the creation of pores on the surface of the samples, which enhanced the degradation of orange II under UV light. The gap energy decreases from 2.17 eV to 1.25 eV with increasing doping. These results show that thin films doped with Ag exhibit a higher degradation than that obtained by pure CuO. After 5 hours in the case of doping with 50% Ag the percentage of degradation is 43%, on the other hand in the pure case the percentage of degradation is 27%.With this, it can be said that 50% Ag:CuO is a good catalyst because the sample has pores, and therefore a larger catalytic area. Creating pores on the surface of the samples, obtaining a less energy gap enables the creation of a greater number of •Oand OH• that works to disintegrate the dye and give the white color to the solution.

Relief patterns were photoinduced on the surface of a thin film floating on water. The structures have a length of several millimeters with a width of 33 μm. Both the intensity and the polarization of the irradiated light change the characteristics of the generated patterns. The light induced structuration is the result of simultaneously a reversible material transport originated by photoisomerization of azobenzene units and a process of self-organization of the molecules. The structures were used as waveguide or grating to couple light at the air/liquid interface on a short or long distance. The fabrication of waveguides can be extended to any liquid substrates.

Drug delivery systems based upon the blending of Arabic gum and poly(N-vinylpyrrolidone) (AG/PVP) were prepared for the controlled release of acebutolol (Acb) hydrochloride. The prepared blends containing Acb were characterized using different techniques. The presence of physical interactions between the drug and polymer matrices was observed with Fourier-transform infrared spectroscopy. These interactions resulted in the transition of the drug from a crystalline to an amorphous state into the polymeric matrices, as demonstrated by differential scanning calorimetry and X-ray diffraction analysis. The thermogravimetric analysis study confirmed the presence of these interactions, which had a stabilizing effect on the drug against both thermal degradation and crystallinity. The in vitrorelease of Acb from the AG/PVP polymer system was investigated. Each drug-loaded system was used in a tablet formulation. Moreover, an in vitrodissolution study was carried out in three different dissolution media, and comparison of the dissolution profiles of the different dosage forms revealed that the polymer blend matrix had a better release-retarding efficiency. To better understand the release mechanism, the dissolution data were fitted to various release kinetic models.

Strong light–matter interactions in resonant photonic nanostructures open up opportunities for enhancing nonlinear responses. In this work, by applying Fano resonances, we experimentally demonstrate efficient third-harmonic generation (THG) obtained with 2D silicon photonic crystal slabs (PCSs) thanks to the field enhancement in the dielectric layer. A 160-fold enhancement of THG is observed in the silicon PCS compared to the unpatterned silicon film. Through slightly changing the radius of the PCS, tunable THG on a single chip is obtained, paving a way for the optical manipulation of harmonic generation.

Carboxymethylcellulose/poly(ethylene glycol) (CMC/PEG) blend and CMC/PEG/montmorillonite (MMT) nanocomposites were produced by the solvent casting method. The clay, a sodium MMT, was incorporated in the polymer matrix at low weight loadings (from 1 wt% to 7 wt%). The MMT dispersion in the matrix was evaluated by X-ray diffraction, which revealed an intercalated structure of the nanocomposites. Different levels of intercalation have been detected. The changes in morphology caused by the addition of layered silicate on CMC/PEG blend were investigated by scanning electron microscopy (SEM). The SEM images of CMC/PEG blend containing 5% of MMT displayed more homogenous morphology than CMC/PEG blend. The compatibilizing performance of the filler was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The effect of the introduction of the clay on the crystallization temperature, melting temperature and crystallization degree of CMC/PEG revealed that clay behaved as a nucleating agent and enhanced the crystallization rate of PEG. Furthermore, it was demonstrated that the addition of a small percentage of montmorillonite (1%) was enough to improve the thermal stability of the nanocomposites.

In this work the synthesis of hydrogel/clay nanocomposites based on poly(2-hydroxyethyl methacrylate) (HEMA) has been performed through in situ free radical polymerization in order to examine their potential use in biomedical applications as drug carriers. 2-hydroxyethyl methacrylate monomer has been intercalated into the interlayer spaces of a clay mineral using sodium montmorillonite (MMT) nanoparticles and then polymerized. The influence of different amounts of MMT on the structural properties of the resulting novel materials HEMA/MMT was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). X ray diffraction analysis has been used to evaluate the state of dispersion of the clay particles in the hydrogel matrix. TGA, DSC and swelling results have revealed that the clay sheets acted as effective multifunctional cross-linkers. Paracetamol incorporation efficiency in the HEMA/MMT hydrogels was determined by UV–vis spectroscopy. The DSC study revealed an amorphization of paracetamol in the drug loaded hydrogel. The effect of varying the concentration of MMT within the hydrogel was investigated to obtain optimum conditions to control the drug release. The burst effect was significantly reduced and the releasing equilibrium time was extended in the nanocomposites HEMA/MMT in comparison to the HEMA hydrogel.

Self-sustained all-optical poling second-harmonic generation (SHG) experiments are conducted in single-core and multicore dye-doped poly(methyl methacrylate) optical fibers. By tuning the polarization of the fundamental beam, the SHG signal is degraded and is reconstructed spontaneously up to its initial level. We found a new situation in which the photo-induced self-organization of azo polymers creates a well-ordered periodic structure.

We present experimental studies of all-optical poling (AOP) in large-core dye-doped poly(methyl methacrylate) plastic optical fibers. We show that the confinement of light within the fiber core permits us to reach the upper limit of second harmonic generation achievable by AOP using repeated trans-cis isomerization. Quantification of the output power indicates self-seeding that can counteract relaxation of the orientation during readout of the induced nonlinearity.