Comparative Analysis of Two-Photon Absorption and Normal Absorption images of dispersions of β-NaYF4:Yb3+,Er3+ Nanoparticles using fluorescence and two-photon microscopes

openUp-conversion nanoparticles (UCNPs) have emerged as one of the most promising nanomaterials for bioanalytical and biomedical applications. β-NaYF4:Yb3+,Er3+ nanoparticles, with a size less than 40 nm, are currently being studied for diagnostic applications, utilizing regular optical spectroscopies, exploiting their ability to absorb in the infrared (IR) and emit in the visible spectrum. In this study, we performed the first tests to explore the possibility of using them in emission microscopy. Fluorescence microscopy and imaging were employed as the first proof-of-concept to examine the detectability of these nanoparticles using different microscopes, using either normal absorption or two-photon absorption in the IR region, and to detect their emission in the visible spectrum.Up-conversion nanoparticles (UCNPs) have emerged as one of the most promising nanomaterials for bioanalytical and biomedical applications. β-NaYF4:Yb3+,Er3+ nanoparticles, with a size less than 40 nm, are currently being studied for diagnostic applications, utilizing regular optical spectroscopies, exploiting their ability to absorb in the infrared (IR) and emit in the visible spectrum. In this study, we performed the first tests to explore the possibility of using them in emission microscopy. Fluorescence microscopy and imaging were employed as the first proof-of-concept to examine the detectability of these nanoparticles using different microscopes, using either normal absorption or two-photon absorption in the IR region, and to detect their emission in the visible spectrum

Black earths from Veneto and Piedmont (Northern Italy): origin, composition and potential use in different painting techniques

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Smartphone-based food diagnostic technologies: A review

A new generation of mobile sensing approaches offers significant advantages over traditional platforms in terms of test speed, control, low cost, ease-of-operation, and data management, and requires minimal equipment and user involvement. The marriage of novel sensing technologies with cellphones enables the development of powerful lab-on-smartphone platforms for many important applications including medical diagnosis, environmental monitoring, and food safety analysis. This paper reviews the recent advancements and developments in the field of smartphone-based food diagnostic technologies, with an emphasis on custom modules to enhance smartphone sensing capabilities. These devices typically comprise multiple components such as detectors, sample processors, disposable chips, batteries and software, which are integrated with a commercial smartphone. One of the most important aspects of developing these systems is the integration of these components onto a compact and lightweight platform that requires minimal power. To date, researchers have demonstrated several promising approaches employing various sensing techniques and device configurations. We aim to provide a systematic classification according to the detection strategy, providing a critical discussion of strengths and weaknesses. We have also extended the analysis to the food scanning devices that are increasingly populating the Internet of Things (IoT) market, demonstrating how this field is indeed promising, as the research outputs are quickly capitalized on new start-up companies

Non destructive testing methods based on Terahertz radiation and Compressive Sampling

A research contribution on non-destructive and non-invasive testing on avionics, metal and non-metal materials is presented. This is realized exploiting the combination of two topics, which over time have become increasingly popular, such as: Compressive Sampling and THz radiation. Specifically, an innovative approach has been developed, so-called CS-THz, that combines the possibility of irradiating with T-waves the sample under test and then realizing the process of capturing and reconstructing of the image through the CS principles. For this purpose, a CS-THz model has been developed, first studying with simulated tests and then with a campaign of experimental trials as the uncertainty sources at stake and their effects on reconstruction, expanding the study introducing a metrics of indexes quality. In addition, the results of Spectroscopy and Imaging THz applications are shown, in the various configurations (reflection and transmission) in which the THz system can operate and the results of non-invasive and non-destructive tests on ferromagnetic materials studied with the method of induced currents, and on which the principles of CS have been applied in order to be able to make the phases of reconstructions of the acquired electrical signal faster by exploiting graphic units (GPUs) and CUDA

Treating Smalt: A Preliminary SEM-EDX Study of the Effects of Aqueous-based Alkaline Conservation Treatments on Smalt in Wall Paintings

Smalt is a blue cobalt-coloured glass pigment used in European wall paintings from the early Renaissance period that became a popular choice for artists due to its unique tone, availability, and ve..

Cross-Nucleation between Concomitantly Crystallizing \uce\ub1- And \uce\ub3-Phases in Polypivalolactone: Secondary Nucleation of One Polymorph on Another

Cross-nucleation between polymorphs occurs when a new crystal structure nucleates on the surface of a pre-existing crystal of a different modification. The understanding of the phenomenon is still mostly phenomenological and qualitative. Here, we report quantitative measurements of cross-nucleation rate of the \uce\ub1 phase of polypivalolactone on its \uce\ub3 phase, during melt crystallization over a large temperature range. The cross-nucleation kinetics is well modeled as heterogeneous secondary nucleation of one polymorph on another, in which the formation of a viable \uce\ub1-phase nucleus on the surface of \uce\ub3-crystals is the rate-limiting step. According to this analysis, cross-nucleation can occur because the interfacial energy between the two structures is small, and the nucleation free energy barrier is similar to that for secondary nucleation within the same polymorph in crystal growth. Some peculiar aspects of cross-nucleation with respect to conventional heterogeneous nucleation, arising from the continuous growth of the nucleating substrate, are also highlighted