This study examined the incorporation of benzalkonium chloride into palygorskite and montmorillonite, assessing their potential as drug carriers. The aim was to evaluate the use of both clay minerals as viable options for antibacterial drug delivery. Various amounts (0.5, 1.0 and 2.0 times the cation-exchange capacity) of benzalkonium chloride were incorporated into both clay minerals, and the resulting materials were characterized using Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and elemental analysis using both CHNS-O elemental analysis and energy-dispersive X-ray spectroscopy. The Fourier-transform infrared spectroscopy and elemental analysis results indicate that benzalkonium chloride was incorporated successfully into the clay minerals. The X-ray diffraction traces of organo-montmorillonite indicate that the d-value increased as benzalkonium chloride content increased, confirming the intercalation of benzalkonium chloride within the montmorillonite interlayer space. By contrast, this behaviour was not observed for palygorskite. For the benzalkonium chloride-release studies, an initial burst release was found within the first 5 h, followed by a sustained release of benzalkonium chloride during the remaining testing time (24 h). Drug-release profiles were similar for modified palygorskite or montmorillonite during the testing time (24 h). Both clay minerals modified with benzalkonium chloride are promising materials for use as antibacterial fillers for several applications, including in the dental care industry.

This study aimed to evaluate the influence of pH changes on morphometric parameters of casein micelles and a general overview of their conformational structure through microscopy techniques, Raman spectroscopy and multivariate analysis. It was found that casein micelles morphology and protein secondary structure depend strongly upon pH. The changes of arithmetic average roughness (Ra), size, and shape of casein micelles at different pH are properly characterized by atomic force and cryo-transmission electron microscopy. Morphometric changes of casein micelles were correlated correctly with folding and unfolding of casein molecules as evaluated by Raman spectroscopy when the pH was varied. The novelty of this contribution consists in demonstrating that there is a close structure-functionality relationship between the morphometric parameters of proteins and their secondary structure. Knowledge about casein micelles can help improve their use of its diverse applications.

Fluorescence techniques have been widely used by scientists to reveal valuable information from biological samples, but in food science, small progress is known due to the complexity of the samples. In this study, two different biological samples, garlic skin (GS) and agave fibers (AF), were used to evaluate the techniques of confocal laser scanning microscopy (CLSM) and total internal reflection fluorescence (TIRF) microscopy, to obtain valuable information on the fiber size of the samples. A compositional characterization with calcofluor white in CLSM was achieved, but a superficial characterization of the samples with TIRF was made, evidencing fiber sizes of 398.67 ± 48.47 nm and 677.38 ± 76.88 nm for GS and AF, respectively. This work reveals that only an untreated sample can be used with the two techniques in the same microscope. In addition, it is possible to characterize the sample only using a spatial field of research and which valuable information about the structure of the material is found. This work provides the opportunity to use advanced fluorescence techniques for elucidation of structures shortly before studied with these techniques.

The J-PAS survey will soon start observing thousands of square degrees of the Northern Sky with its unique set of 56 narrow band filters covering the entire optical wavelength range, providing, effectively, a low resolution spectra for every object detected. Active galaxies and quasars, thanks to their strong emission lines, can be easily identified and characterized with J-PAS data. A variety of studies can be performed, from IFU-like analysis of local AGN, to clustering of high-z quasars. We also expect to be able to extract intrinsic physical quasar properties from the J-PAS pseudo-spectra, including continuum slope and emission line luminosities. Here we show the first attempts of using the QSFit software package to derive the properties for 22 quasars at 0.8 < z < 2 observed by the miniJPAS survey, the first deg2 of J-PAS data obtained with an interim camera. Results are compared with the ones obtained by applying the same software to SDSS quasar spectra.