ZORRO: zirconium oxide resonators for all-in-one Raman and whispering-gallery-mode optical sensing.

We report the observation of whispering-gallery modes in 2 µm-sized SiO2/ZrO2 core/shell beads utilized as all-dielectric Raman enhancers. This allows us to achieve simultaneous optical and Raman ultrasensitive detection with a single spectral analysis. This opportunity opens exciting perspectives for the multimodal chemical sensing and fabrication of optical fiber devices.

Probing lysine mono-methylation in histone H3 tail peptides with an abiotic receptor coupled to a non-plasmonic resonator.

Binder and effector molecules that allow studying and manipulating epigenetic processes are of biological relevance and pose severe technical challenges. We report the first example of a synthetic receptor able to recognize mono-methylated lysines in a histone H3 tail peptide, which has relevant functions in epigenetic regulation. Recognition is robust and specific regardless of the position and the number of mono-methylated lysines along the polypeptide chain. The peptide is first captured in solution by a tetraphosphonate cavitand (Tiiii) that selectively binds its Lys-NMe+ moieties. Separation from solution and detection of the peptide-Tiiii complexes is then enabled in one single step by an all dielectric SiO2-TiO2 core-shell resonator (T-rex), which captures the complex and operates fully reproducible signal transduction by non-plasmonic surface enhanced Raman scattering (SERS) without degrading the complex. The realized abiotic probe is able to distinguish multiple mono-methylated peptides from the single mono-methylated ones.

Indirect resin composite restorations: evaluation of polymerization of luting agents by means of micro-Raman spectrophotometry.

AIM: The degree of conversion of a luting composite cement influences its clinical performance. Aim of the study was to evaluate the degree of conversion of 4 different composite cements by means of micro Raman spectrophotometry. METHODS: Forty-four cylindrical onlays of different and defined thickness (1, 2, 3, 4 mm) were built using a custom made template. The onlays were made in composite material (Signum, Heraeus; shade A 3,5) and cemented onto a glass plate with different luting materials: dual curing (Variolink II, Calibra) and light curing (Venus flow, Tetric flow). The lamp tip was shielded in order to have the light reach the cement only through the onlay. Samples were divided into 12 groups (N.=3), differing in onlay thickness and luting material. Each sample was examined in three spots by a micro-Raman spectrophotometer (Dilor Hr-Labram). The conversion degree was evaluated by analyzing the variations in intensity of the 1638 cm(-1) aliphatic peak (C=C), characteristic of all Bis-GMA containing materials, related to the invariant 1608 cm(-1) (C-C of the aromatic ring). RESULTS: All materials show good polymerisation results below 1 mm and 2 mm onlays. Below onlays thicker than 3 mm a constant degree of conversion throughout the surface of samples could not be found: spots with satisfactory polymerisation and spots with insufficient polymerisation were found. CONCLUSIONS: Onlay thickness has a key role in cement conversion. The thicker the onlay, the less predictable the conversion.

Phase transformations in bulk nanostructured potassium niobiosilicate glasses.

In potassium niobiosilicate (KNS) glasses, nanostructuring can be driven and controlled by thermal treatments at the glass transition temperature and/or by modulation of the chemical composition. The tight relationship between nanostructure and nonlinear optical properties suggests these bulk nanomaterials as an appealing route to nanophotonics. The focus of this paper is placed on assessing the phase transformations which occur in these materials upon annealing at the glass transition temperature and subsequent heating. High-temperature resolved X-ray diffraction (HTXRD) and high-resolution transmission electron microscopy (HRTEM) experiments are integrated with previously published results for in-depth insight. It will be shown that nanostructuring evolves from nucleation of niobium-rich nanocrystals, which are up to 20 nm large, uniformly distributed in the matrix bulk, and metastable. Formation kinetics as well as phase transformation of the nanocrystals are determined by the glass composition. Depending on it, nanocrystal nucleation can be preceded or not by phase separation, and the nanocrystals' phase transition can be of first or second order.