No abstract

The hydroxyapatite-supported silver nanoparticles were synthesized and used as a new type of catalyst for the discoloration of a model cationic dye in a Fenton-like process. The structure and morphology of the catalyst were investigated by FTIR, TEM and SEM before and after reaction. The main factors that could influence the catalytic activity were summary investigated. The catalytic activity was monitored by evaluating the discoloration degree from the absorbance data recorded in the visible spectra. The results obtained during these preliminary investigations are very promising from applicative point of view.

Textiles with antimicrobial functionality have been intensively and extensively investigated in the recent decades, mostly because they are present in everyday life in various applications: medicine and healthcare, sportswear, clothing and footwear, furniture and upholstery, air and water purification systems, food packaging etc. Their ability to kill or limit the growth of the microbial population in a certain context defines their activity against bacteria, fungi, and viruses, and even against the initial formation of the biofilm prior to microorganisms’ proliferation. Various classes of antimicrobials have been employed for these highly specialized textiles, namely, organic synthetic reagents and polymers, metals and metal oxides (micro- and nanoparticles), and natural and naturally derived compounds, and their activity and range of applications are critically assessed. At the same time, different modern processing techniques are reviewed in relation to their applications. This paper focuses on some advances and challenges in the field of antimicrobial textiles given their practical importance as it appears from the most recent reports in the literature.

The purpose of this study was to test the structural improving that may be acquired by adding hydroxyapatite microparticles bearing or not silver nanoparticles to three different commercial products commonly used in dental practice. The practical part of this study consisted in the preparation of a common protocol of nine samples resulting from the creation of cavities and their filling similarly to the solving of different clinical situations of carious processes, extracted teeth belonging to both the anterior and the posterior area, with different architectures of the loss of dental substance. Before use, both HA and HA/AgNP have been subjected to calcination in an oven at 6000C for three hours in order to eliminate the residual organic matter. The structural changes have been studied on three types of composites known in the medical practice under the tradenames of Ceram X Duo, Swiss Tec and Herculite XRV Ultra. The structural changes materialized at the level of dentinal component are clearly visible in the SEM images recorded for each starting commercial material. Thus, the addition of HA with high polydispersity (within the range of tens of nanometers and several microns) was effective on lowering the surface rugosity and apparent macro-porosity, while enhancing the phase mixing and component cohesion, but only in the case of Ceram X Duo and Swiss Tec materials. For Herculite XRV Ultra these effects seems to be limited or even reversed, phenomenon that could be explained by the fact that this material already contains nano-fillers, and their concentration tends to saturation.