We use two water based synthetic approaches to LaF 3 :Nd 3 + nanoparticles (NPs), hydrothermal microwave treatment (HTMW) and co-precipitation (CO) technique, with different temperature of the reaction mixture to study the correlation between the degree of crystallinity of LaF 3 :Nd 3 + NPs and their fluorescence properties. We showed that the fluorescence spectra and quenching kinetics can be a powerful tool to reveal the crystal lattice defects, namely agglomerations of the dopant ions (Nd 3 + ) and the OH À positioned in the volume of the doped NPs. We found that reduced number of such crystal lattice defects as Nd 3 + pairs and clusters and the OH groups in the volume of the HTMW NPs leads to much higher fluorescence brightness than for CO NPs. The higher temperature of reaction mixture during HTMW synthesis results in better crystallinity and much higher fluorescence brightness of the produced NPs. But we believe that these results could be applied more generally to the development of synthetic strategies for bright fluorescent NPs. In sum, it's not the condition of NPs surface, but the degree of their crystallinity should be a major concern while choosing the synthetic path, as it generally predetermines their fluorescent properties.

Nanomaterials are prospective candidates for the elimination of viruses due to their multimodal mechanisms of action. Here, we tested the antiviral potential of a largely unexplored nanoparticle of cerium dioxide (CeO2). Two nano-CeO2 with opposing surface charge, (+) and (−), were assessed for their capability to decrease the plaque forming units (PFU) of four enveloped and two non-enveloped viruses during 1-h exposure. Statistically significant antiviral activity towards enveloped coronavirus SARS-CoV-2 and influenza virus was registered already at 20 mg Ce/l. For other two enveloped viruses, transmissible gastroenteritis virus and bacteriophage φ6, antiviral activity was evidenced at 200 mg Ce/l. As expected, the sensitivity of non-enveloped viruses towards nano-CeO2 was significantly lower. EMCV picornavirus showed no decrease in PFU until the highest tested concentration, 2000 mg Ce/l and MS2 bacteriophage showed slight non-monotonic response to high concentrations of nano-CeO2(−). Parallel testing of antiviral activity of Ce3+ ions and SiO2 nanoparticles allows to conclude that nano-CeO2 activity was neither due to released Ce-ions nor nonspecific effects of nanoparticulates. Moreover, we evidenced higher antiviral efficacy of nano-CeO2 compared with Ag nanoparticles. This result along with low antibacterial activity and non-existent cytotoxicity of nano-CeO2 allow us to propose CeO2 nanoparticles for specific antiviral applications.

Abstract. The fluorescence kinetics and spectral intensity ratio (FIR) methods for contactless optical temperature measurement in the NIR spectral range with Nd 3+ doped YAG micro-and YPO 4 nanocrystals are developed, tested and the problems are revealed. The requirements for optical temperature RE doped crystalline nanoparticles sensors working in NIR spectral range are formulated. Keywords

Nanomaterials have been proposed as good candidates for the elimination of viruses due to their multimodal mechanisms of action. Here, we tested the antiviral potential of cerium dioxide (CeO2) nanoparticles which is largely unexplored.Two types of nano-CeO2 particles with opposing surface charge, nano-CeO2(+) and nano-CeO2(-), were assessed for their capability to decrease the plaque forming units (PFU) of four enveloped and two non-enveloped viruses during 1 h exposure. Statistically significant antiviral activity of nano-CeO2 towards enveloped coronavirus SARS-CoV-2 and influenza virus A/WSN/1933 was registered already at 20 mg Ce/l. Significant decrease in PFU of other two enveloped viruses, transmissible gastroenteritis virus TGEV and bacteriophage φ6 was evidenced at 200 mg Ce/l. For all the enveloped viruses the maximum reduction of PFU after 1 h exposure to nano-CeO2 exceeded 2 logs, that has been considered as the lowest biologically meaningful activity in antiviral applications. For most of the enveloped viruses, 1 h exposure to nano-CeO2 resulted in ≥ 4 log reduction in PFU. As expected, the sensitivity of non-enveloped viruses towards nano-CeO2 was significantly lower than that of enveloped viruses. Until the highest tested concentration, 2000 mg Ce/l neither of the nano-CeO2 showed an effect on picornavirus EMCV and only nano-CeO2(-) caused a slight non-monotonic response in MS2 bacteriophage.Parallel testing of antiviral activity of Ce3+ ions and SiO2 nanoparticles allows to conclude that nano-CeO2 activity was due to neither released Ce3+ ions nor nonspecific effects of any nanosized particulate. Interestingly, we did not evidence any significant antiviral activity of Ag nanoparticles at 1 h exposure. This result referred to notably higher antiviral activity of nano-CeO2 compared with nanosilver that has been generally considered as active against viruses. Although exhibiting antiviral effects, the antibacterial activity of nano-CeO2 was very low. These results along with non-existent cytotoxicity nano-CeO2 allow us to propose nano-CeO2 for specific antiviral applications.

The method is proposed for express diagnostics of diseases according to the data of mass spectrometric analysis of exhaled air. An algorithm for calculating the probability of diseases has been developed and tested. The results of data processing of patients treated in two oncological clinics are presented. The calculation of the probability of disease according to the data of mass spectrometric analysis of exhaled air is based on attributing the mass spectrum of the tested patient to the mass-spectra of the corresponding control group. Each control group is formed by collecting an array of spectra from at least ten patients with the same disease. Diagnostics is performed by transforming the matrix of spectra of the control group and the spectrum of a patient being tested into the space of the principal components. The probability of a disease is determined by the Euclidean distance of the patient's coordinates from the centroid of the control group in the multidimensional space of these principal components.