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Visiting urban green and blue spaces improves the quality of life in cities as it helps to preserve human-nature bonds. In this context, the role of urban parks and forests has been well-recognised; however, much less is known about the landscapes of inland water bodies. To fill this gap, the study aimed to identify spatiotemporal patterns of recreational activities in the urban riverscape in relation to the visitors’ residential proximity. Also, survey results were combined with spatial and remote sensing data to determine how the spatial characteristics of the riverscape affect its recreational use. The case of Warsaw, Poland, was used. The results indicated that the riverscape serves as a local park for the neighbouring communities, while it is rather a warm-weekend attraction for far-living ones. Visitors concentrate in the city centre, and spread out along the communication paths; however, spatial patterns of the magnitude of particular activities also show interbank differences. Spatial error models of drivers of riverscape recreation revealed (1) the multifaceted role of trees in densely visited areas and (2) the importance of physical availability for contact with the urban river. These findings expand knowledge on the recreational use of urban rivers by exploring its place-related motivations.

Persistent luminescence (PersL) materials show long-lasting emission after irradiation with excitation light. Usually, to obtain PersL, excitation with ultraviolet (UV) or visible light is necessary, which limits the use of this phenomenon when the material is in a non-transparent medium for excitation light. A solution to this problem comes from upconverting nanoparticles (UCNPs), which convert near-infrared light, usually not absorbed by such media as polymers or biological tissues, to higher-energetic UV photons, recharging the PersL phosphors. In this article, we report composite materials consisting of PersL phosphor and UCNPs, i.e. SrAl2O4:Eu2+ or ZnGa2O4:Cr3+ and upconverting LiYbF4:Tm3+@LiYF4 core@shell nanoparticles. These materials show dual-emission properties - bright upconversion from near-infrared (NIR at 975 nm) to ultraviolet (UV at 347 nm) and long-lasting PersL in the visible light range. The obtained composite materials present intense, persistent luminescence after the NIR laser excitation. This article proves efficient energy transfer from UCNPs to PersL phosphor and opens new possibilities in the design and synthesis of composite materials. By employing the high-resolution 3D-printing technology, we experimentally confirmed the possibility of multi-modal optical information storage by applying the synthesized materials, developing multi-dimensional microstructured patterns with QR code, letters and first bi-modal, single- and double-layered 8-bit codes based on the combination of PersL and upconversion emission. [ABSTRACT FROM AUTHOR]

Nanoparticles containing lanthanide (Ln3+) ions in their structure have become one of the most important tools in nanomedicine, mainly due to their appealing spectroscopic properties. The unique energy level structure of Ln3+ allows for the generation of characteristic luminescence, which depends highly on the temperature. It is possible to use the intensity ratio between two emission lines of a single Ln3+ ion or the emission of two different ions to monitor the system's temperature. This approach often leads to the high sensitivity of such thermometers; however, the most important is the possibility of remote temperature sensing. That property allows for monitoring various physiological processes in living organisms and is helpful in theranostics. What is essential for bioapplications is that the excitation and emission wavelengths of Ln3+ ions can occur within three spectral ranges, known as optical transparency windows (biological windows). The biological materials, such as tissues, are transparent to radiation with wavelengths in the ranges of 750-950 nm, 1000-1350 nm and 1500-1800 nm. In this article, we review the state of the art regarding nanoparticles doped with Ln3+ ions for applications in temperature sensing within optical transparency windows regarding both excitation and emission wavelengths. The information provided in our review article will enable the selection of the type of nanothermometer for specific applications, help in selection of the emission or excitation wavelength, understanding the differences between systems based on down-shifting and upconversion phenomena, recognizing differences in the thermosensitive properties of various lanthanide ions, such as Nd3+, Tm3+, or Er3+, as well as the matrices and chemical compounds that form the basis for nanoparticles. [ABSTRACT FROM AUTHOR]