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Highlights: [•] Sol–gel method was successfully applied to obtain an orthorhombic BaAl2O4 doped with Eu3+ ions. [•] Prepared compound structures were confirmed by X-Ray diffraction and TEM analysis. [•] Unusual spectroscopic properties appeared in luminescence spectra were described. [•] A detailed analysis of the luminescence spectra by the Judd–Ofelt theory has been performed. [ABSTRACT FROM AUTHOR]

Abstract: Nanosized CaAl2O4 powders doped with Eu3+ and charge compensated with Na+ co-doping were synthesized with modified Pechini''s method. The structural properties of the powders calcined at 900–1100°C where characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The grains with monoclinic structure formed quite large and aggregated crystallites with irregular shapes and sizes in the range of 100–500nm. The photoluminescent properties of the phosphores co-doped with different Eu3+ ions concentration (0.5–5mol%) were investigated by excitation and emission spectroscopy at room and low (77K) temperatures. The effect of charge compensation on luminescence properties was noticed. To explain these differences a detailed analysis of luminescence spectra by the Judd–Ofelt theory has been performed. [Copyright &y& Elsevier]

Abstract: Transparent Eu3+ doped MgAl2O4 and Eu3+/Na+ co-doped MgAl2O4 nanoceramics have been obtained by a low-temperature high-pressure (LTHP) sintering process using crystalline powders prepared by sol–gel method. Structural properties have been studied by X-ray diffraction (XRD) and analyzed by Rietveld method. Luminescent properties of nanoceramics were investigated by excitation and emission spectroscopy at room and liquid nitrogen temperatures and by measuring luminescence decays. Comparison between nanopowders and nanoceramics has shown modification of their structural and spectroscopic characteristics. Differences of luminescence properties were studied and analyzed with Judd–Ofelt theory and also the effect of Na+ co-doping have been discussed. [Copyright &y& Elsevier]

Abstract: In this paper, a modified sol–gel method was employed to prepare nanostructured MgAl2O4 spinel powders doped with Tb3+ ions and thermally treated at 700 and 1000°C for 3h. The structural properties of the prepared at 700 and 1000°C powders where characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). According to obtained XRD patterns the formation of single-phase spinels after calcination was confirmed. The XRD analyses demonstrated that the powders were single-phase spinel nanopowders with high crystallite dispersion. The Rietveld method was applied to calculate lattice parameters. The averaged spinel particle size was determined to be ∼10nm for calcination at 700°C and ∼20nm at 1000°C. The emission and excitation spectra measured at room and low temperature (77K) for the samples calcined at 700 and 1000°C demonstrated characteristic spectra of Tb3+ ions. The effect of MgAl2O4:Tb3+ grain sizes on luminescence properties was noticed. [Copyright &y& Elsevier]

Abstract: Nanoplates of the MgAl2O4 spinel doped with Eu3+ ions were prepared by a microwave assisted hydrothermal method. Structural properties of the precursor calcined at 700 and 1000 oC powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). According to the obtained XRD patterns the formation of single-phase spinels after calcination was confirmed. The average spinel particle size was determined to be 11nm after calcination at 700°C and it increased up to 14nm after calcination at 1000°C. The photoluminescent properties of prepared powders with different Eu3+ ion concentrations (0–5%mol) were investigated using excitation and emission spectroscopy at room and low temperatures (77K). [Copyright &y& Elsevier]

In recent years, intensive research has focused on lanthanide-doped nanoparticles (NPs) used as noncontact temperature sensors, particularly in nanomedicine. These NPs must be capable of excitation and emission within biological windows, where biological materials usually show better transparency for radiation. In this article, we propose that NPs sensitized with Er 3+ ions can be applied as temperature sensors in biological materials. We synthesized the NPs through a reaction in high-boiling solvents and confirmed their crystal structure and the formation of core@shell NPs by using X-ray diffraction, high-resolution transmission electron microscopy, and element distribution mapping within the NPs. NaErF 4 @NaYF 4 , NaYF 4 :12.5% Er 3+ , 2.5% Tm 3+ @NaYF 4 , NaYF 4 :7.5% Er 3+ @NaYF 4 , and NaYF 4 :12.5% Er 3+ , 2.5% Ho 3+ @NaYF 4 exhibited intense upconversion (UC) emission under 1532 nm laser excitation detectable also in the whole human blood. We propose that this UC results from energy transfer between Er 3+ ions and from Er 3+ to Tm 3+ or Ho 3+ codopants. To determine the mechanism of UC, we measured the dependence of the emission band intensities on the laser power densities. Importantly, we also analyzed the temperature-dependent emission of the NPs within the 295-360 K range. Based on the collected emission spectra, we calculated the luminescence intensity ratios (LIRs) of the emission bands to assess their potential for optical temperature sensing. The temperature-sensing properties varied with the concentration of Er 3+ ions and the presence of additional Tm 3+ or Ho 3+ codopants. Depending on the NP composition and the emission bands used for luminescence ratio calculations, the maximum relative temperature sensitivity ranged from 4.55%·K -1 to 1.12%·K -1 , with temperature resolution between 0.05 and 2.53 K at room temperature. Finally, as proof of using NPs as temperature sensors in biomedicine, we successfully measured the temperature-dependent emission of NaYF 4 :7.5% Er 3+ @NaYF 4 NPs dispersed in whole blood under 1532 nm excitation. We demonstrated that the ratio of Er 3+ ion emission bands changes with temperature, indicating that these NPs have potential applications in temperature sensing within biological environments. We also confirmed the properties of NPs as temperature sensors by measuring the temperature reading uncertainty and the repeatability of the LIR readings during heating-cooling cycles, thereby confirming the excellent properties of the studied systems as temperature sensors.

The authors are proposing a theoretical model explaining the behavior of individuals tested through experiments on obedience toward authority conducted according to Milgram's paradigm. Their assumption is that the participant faces typical avoidance-avoidance conflict conditions. Participant does not want to hurt the learner in the adjacent room but he or she also does not want to harm the experimenter. The solution to this conflict, entailing hurting on of the two, may be different depending on the spatial organization of the experiment. In the study, experimental conditions were modified, so that the participant was (vs. was not) in the same room as the experimenter and was (vs. was not) in the same room as the learner. Forty individuals (20 women and 20 men) were tested in each of the four experimental conditions. It turns out that the physical presence of the experimenter was conducive to obedience, while the physical presence of the learner reduced it.

The upconversion phenomenon allows for the emission of nanoparticles (NPs) under excitation with near-infrared (NIR) light. Such property is demanded in biology and medicine to detect or treat diseases such as tumours. The transparency of biological systems for NIR light is limited to three spectral ranges, called biological windows. However, the most frequently used excitation laser to obtain upconversion is out of these ranges, with a wavelength of around 975 nm. In this article, we show an alternative - Tm 3+ /Er 3+ -doped NPs that can convert 1208 nm excitation radiation, which is in the range of the 2 nd biological window, to visible light within the 1 st biological window. The spectroscopic properties of the core@shell NaYF 4 :Tm 3+ @NaYF 4 and NaYF 4 :Er 3+ ,Tm 3+ @NaYF 4 NPs revealed a complex mechanism responsible for the observed upconversion. To explain emission in the studied NPs, we propose an energy looping mechanism: a sequence of ground state absorption, energy transfers and cross-relaxation (CR) processes between Tm 3+ ions. Next, the excited Tm 3+ ions transfer the absorbed energy to Er 3+ ions, which results in green, red and NIR emission at 526, 546, 660, 698, 802 and 982 nm. The ratio between these bands is temperature-dependent and can be used in remote optical thermometers with high relative temperature sensitivity, up to 2.37%/°C at 57 °C. The excitation and emission properties of the studied NPs fall within 1 st and 2 nd biological windows, making them promising candidates for studies in biological systems.

In recent years, nanotechnology has found widespread applications in environmental monitoring, medical applications, plant fertilisers, cosmetics and others. Therefore, it is important to study nanomaterials' influence and subsequent risks to the environment and organisms (from production to disposal). Therefore, in the present study, the toxic effects of two surface modifications (poly (ethylene glycol)-neridronate, PEG-Ner and poly (acrylic acid), PAA) in comparison to unmodified, 26 nm- and 52 nm-sized core@shell lanthanide-doped upconverting nanoparticles (UCNPs, NaYF 4 :Yb 3+ ,Er 3+ @NaYF 4 ) were analysed. Wheat seedlings (Triticum aestivum L.) were chosen as a model organism since this species is one of the most widely cultivated crops. The influence of UCNPs (at concentrations of 0, 10, 50, and 100 μg/mL) on germination percentage, germination rate and growth was studied based on morphological parameters such as root number, root and hypocotyl length, and root and hypocotyl mass. In addition, an assay based on Evans blue staining was conducted to analyse damaged cell membranes and cell death. The type, size and concentration of UCNPs influenced the growth but not the germination of wheat. 52-nm-sized ligand-free UCNPs and the 26-nm-sized UCNPs/PAA decreased plant growth. Moreover, the ligand-free 26-nm-sized UCNPs interacted with the root cell membranes of seedlings. No significant changes were observable regarding viability (tetrazolium chloride reduction assay), oxidative stress and electrolyte leakage from root cells in plants incubated with ligand-free 26-nm-sized UCNPs. Overall, we have shown that the ligand-free UCNPs (of both sizes) had the strongest toxic effect; PAA-modified UCNPs were toxic only at smaller sizes and PEG-Ner-modified UCNPs had no toxic impact. Therefore, PEG-Ner was identified as the safest surface compound among the UCNPs investigated in the study, which may neutralise the harmful effects of nanoparticles on plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The properties of upconverting nanoparticles (UCNPs) are crucial for their applications in biomedicine. For studies of organisms and biological materials, the penetration depth of excitation light is also essential as the depth from which the luminescence can be detected. Currently, many researchers are trying to obtain UCNPs with intense emission under excitation wavelengths from the biological transparency windows to increase the penetration depth. However, studies comparing the properties of various types of UCNPs in real conditions are rare. This article shows how deep the 808, 975, 1208, and 1532 nm laser radiation penetrates human blood. Moreover, we determined how thick a layer of blood still permits for observation of the luminescence signal. The measured luminescence properties indicated that the near-infrared light could pass through the blood even to a depth of 7.5 mm. The determined properties of core/shell NaErF 4 /NaYF 4 materials are the most advantageous, and their emission is detectable through 3.0 mm of blood layer using a 1532 nm laser. We prove that the NaErF 4 /NaYF 4 UCNPs can be perfect alternatives for the most studied NaYF 4 :Yb 3+ ,Er 3+ /NaYF 4 . Additionally, the setup proposed in this article can potentially decrease reliance on animal testing in initial biomedicine research., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Tomasz Grzyb reports financial support was provided by National Science Centre Poland. Natalia Jurga reports financial support was provided by European Social Fund., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Photon upconversion is an intensively investigated phenomenon in the materials sciences due to its unique applications, mainly in biomedicine for disease prevention and treatment. This study reports the synthesis and properties of tetragonal LiYbF 4 :Tm 3+ @LiYF 4 core@shell nanoparticles (NPs) and their applications. The NPs had sizes ranging from 18.5 to 23.7 nm. As a result of the energy transfer between Yb 3+ and Tm 3+ ions, the synthesized NPs show intense emission in the ultraviolet (UV) range up to 347 nm under 975 nm excitation. The bright emission in the UV range allows for singlet oxygen generation in the presence of hematoporphyrin on the surface of NPs. Our studies show that irradiation with a 975 nm laser of the functionalized NPs allows for the production of amounts of singlet oxygen easily detectable by Singlet Oxygen Sensor Green. The high emission intensity of NPs at 800 nm allowed the application of the synthesized NPs in an upconversion-linked immunosorbent assay (ULISA) for highly sensitive detection of the nucleoprotein from SARS-CoV-2, the causative agent of Covid-19. This article proves that LiYbF 4 :Tm 3+ @LiYF 4 core@shell nanoparticles can be perfect alternatives for the most commonly studied upconverting NPs based on the NaYF 4 host compound and are good candidates for biomedical applications., Competing Interests: Declaration of Competing Interest The authors do not declare any competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Recently, materials revealing the upconversion (UC) phenomenon, which is a conversion of low-energy photons to higher-energy ones, have attracted considerable attention in luminescence thermometry due to the possibility of precise and remote optical thermal sensing. The most widely studied type of luminescent thermometry uses a ratiometric approach based on changes in the UC luminescence intensity, mainly of lanthanide ions' thermally coupled energy levels. In this work, NaYF 4 :Ho 3+ @NaYF 4, and NaYF 4 :Ho 3+ , Er 3+ @NaYF 4 nanoparticles (NPs) were synthesized by the controlled reaction in oleic acid and octadecene at 573 K. The obtained nanoparticles had hexagonal structures, oval shapes, and average sizes of 22.5 ± 2.2 nm and 22.2 ± 2.0 nm, respectively. The spectroscopic properties of the products were investigated by measurements of the UC emission under 1151 nm laser excitation in the temperature range between 295 to 378 K. The sample doped with Ho 3+ and Er 3+ ions showed unique behavior of enhancing emission intensity with the temperature. The relative sensitivity determined for the NPs containing Ho 3+ and Er 3+ ions, reached the maximum value of 1.80%/K at 378 K. Here, we prove that the NaYF 4 :Ho 3+ , Er 3+ @NaYF 4 system presents unique and excellent optical temperature sensing properties based on the luminescence intensity ratios of the near-infrared bands of both Ho 3+ and Er 3+ ions., (© 2023. Springer Nature Limited.)

Various types of nanoparticles (NPs) have been widely investigated recently and applied in areas such as industry, the energy sector, and medicine, presenting the risk of their release into the environment. The ecotoxicity of NPs depends on several factors such as their shape and surface chemistry. Polyethylene glycol (PEG) is one of the most often used compounds for functionalisation of NP surfaces, and its presence on the surfaces of NPs may affect their ecotoxicity. Therefore, the present study aimed to assess the influence of PEG modification on the toxicity of NPs. As biological model, we chose freshwater microalgae, a macrophyte and invertebrates, which to a considerable extent enable the assessment of the harmfulness of NPs to freshwater biota. SrF 2 :Yb 3+ ,Er 3+ NPs were used to represent the broad group of up-converting NPs, which have been intensively investigated for medical applications. We quantified the effects of the NPs on five freshwater species representing three trophic levels: the green microalgae Raphidocelis subcapitata and Chlorella vulgaris, the macrophyte Lemna minor, the cladoceran Daphnia magna and the cnidarian Hydra viridissima. Overall, H. viridissima was the most sensitive species to NPs, which affected its survival and feeding rate. In this case, PEG-modified NPs were slightly more toxic than bare ones (non-significant results). No effects were observed on the other species exposed to the two NPs at the tested concentrations. The tested NPs were successfully imaged in the body of D. magna using confocal microscopy; both NPs were detected in the D. magna gut. The results obtained reveal that SrF 2 :Yb 3+ ,Er 3+ NPs can be toxic to some aquatic species; however, the structures have low toxicity effects for most of the tested species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

A lot of people are interested in optical thermometry, especially the new single-band ratiometric (SBR) technology for measuring temperature. But since SBR thermometry is still in its infancy, it is highly constrained when compared to the conventional dual-band ratiometric approach. In this paper, we propose a new SBR thermometry technique that is based on both the ground and excited state absorption processes. When these two different processes occur, the green emission of Tb 3+ in the low-cost host of NaSrGd(MoO 4 ) 3 (NSGM) responds to changes in temperature in a way that is the exact opposite of what you would expect. The maximum luminescence intensity was obtained for an optimum terbium concentration of 40% mol. The resulting chromaticity coordinates ( x , y ) and high correlated color temperature (CCT) values of the doped phosphors give a thermally stable cold emission in the green region with a color purity of about 92%. Using this intriguing characteristic as a foundation, sensitive SBR thermometry has been successfully developed, and the optical properties of the material have also been thoroughly researched. At room temperature, the relative sensitivity reaches its maximum value of 10.9% K -1 . These findings may give important information that may be used in the design of new luminescent thermometers that have excellent performance.

Experiments on obedience to authority conducted under the paradigm developed by Milgram have demonstrated that empathy plays either no or a very limited role in determining participants' behaviors. This study proposes that this occurs due to participants empathizing with both "learners" and experimenters. Empathy with learners makes participants withdraw from the experiment, while empathy with experimenters makes them continue. Therefore, the more that participants are characterized by dispositional empathy, the more they are reluctant to hurt learners but, at the same time, the more they try not to disappoint experimenters. This study investigates the effects of empathy being situationally directed toward learners. After manipulating the alleged similarities between "teachers" and "learners" in terms of crucial attitudes and values, the degree to which teachers obeyed experimenters and were willing to electrocute learners was measured. The results confirm that situationally directed empathy reduces participants' obedience to experimenters., Competing Interests: Declaration of competing interest We have no conflicts of interest to disclose. All authors declare that they have no conflicts of interest., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Numerous experiments have proven that mimicry is highly beneficial (mainly to the mimicker but also to the mimickee). Some studies have shown initial data suggesting the potential of applying this knowledge to business settings. In the present paper we unpack this issue in two ways. First, by presenting potential benefits stemming from mimicry for the mimicking dyad, and second for the business environment represented by the mimicker. Two consecutive studies: a Pretest and a Main Experiment run in natural settings showed great potential in improving the assessments of quality of service provided by verbally mimicking (or not). The results of both studies showed that mimicry offers benefits for the mimicker (increased employee kindness and employee evaluation), and also spillover to the organization/company represented by the mimicking employee (increased opinion of and willingness to return to the shop/hotel). Future research directions and limitations are discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kulesza, Dolinski, Muniak, Borkowska, Bibikova and Grzyb.)

The COVID-19 crisis requires fast and highly sensitive tests for the early stage detection of the SARS-CoV-2 virus. For detecting the nucleocapsid protein (N protein), the most abundant viral antigen, we have employed upconversion nanoparticles that emit short-wavelength light under near-infrared excitation (976 nm). The anti-Stokes emission avoids autofluorescence and light scattering and thus enables measurements without optical background interference. The sandwich upconversion-linked immunosorbent assay (ULISA) can be operated both in a conventional analog mode and in a digital mode based on counting individual immune complexes. We have investigated how different antibody combinations affect the detection of the wildtype N protein and the detection of SARS-CoV-2 (alpha variant) in lysed culture fluid via the N protein. The ULISA yielded a limit of detection (LOD) of 1.3 pg/mL (27 fM) for N protein detection independent of the analog or digital readout, which is approximately 3 orders of magnitude more sensitive than conventional enzyme-linked immunosorbent assays or commercial lateral flow assays for home testing. In the case of SARS-CoV-2, the digital ULISA additionally improved the LOD by a factor of 10 compared to the analog readout.

Pollution of the environment with plastic is an important concern of the modern world. It is estimated that annually over 350 million tonnes of this material are produced, wherein, despite the recycling methods, a significant part is deposited in the environment. The plastic has been detected in the industrial areas, as well as farmlands and gardens in many world regions. Larger plastic pieces degraded in time into smaller pieces including microplastic (MP) and nanoplastic particles (NP). Nanoplastic is suggested to pose the most serious danger as due to the small size, it is effectively taken up from the environment by the biota and transported within the organisms. An increasing number of reports show that NP exert toxic effects also on plants. One of the most common plant response to abiotic stress factors is the accumulation of reactive oxygen species (ROS). On the one hand, these molecules are engaged in cellular signalling and regulation of genes expression. On the other hand, ROS in excess lead to oxidation and damage of various cellular compounds. This article reviews the impact of NP on plants, with special emphasis on the oxidative response., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ekner-Grzyb, Duka, Grzyb, Lopes and Chmielowska-Bąk.)

The unique properties of upconverting nanoparticles are responsible for their various applications in photonic materials, medicine, analytics, or energy conversion. In this work, the NaErF 4 :Tm 3+ @NaYF 4 core@shell nanoparticles were synthesized by reaction in high-boiling point solvents and incorporated into cellulose fibers. Nanoparticles showed intense upconversion under 1532 nm excitation wavelength due to Er 3+ in their structure. Additional co-doping with Tm 3+ ions allowed to shift of the typical green luminescence of Er 3+ ions to red especially demanded in anti-counterfeiting applications. The products' composition, morphology, and structure parameters confirmed their requested properties. The article demonstrates that cellulose fibers are suitable carriers of NaErF 4 :Tm 3+ @NaYF 4 NPs. We also show that the temperature-dependent emission of Er 3+ ions allows for the preparation of temperature-sensing cellulose fibers., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This study explores explicit justifications for recommendations regarding patients' continuing detention in forensic psychiatric wards. We are interested in what arguments are used in recommendations for the continuing detention of involuntarily committed patients made by assessment teams for legal proceedings. Our frequency analysis shows that assessment teams refer predominantly to arguments related to the mental state of the detainee. When recommending a change of security level, the assessment teams frequently refer to behavioural factors. However, very rarely does such argumentation appear in recommendations for continuation of detention at the same security level. Additionally, our qualitative analysis shows a very high level of certainty with which pronouncements about patients' behaviour are made, typically in the absence of any social/institutional context. Our study shows that assessment teams tend to opt for safe decisions that are unlikely to be challenged by legal proceedings and that allow them full control over the patient., Competing Interests: None.

Anhydrobiosis is the ability of selected organisms to lose almost all water and enter a state of reversible ametabolism. Such an organism dries up to a state of equilibrium with dry air. Unless special protective mechanisms exist, desiccation leads to damage, mainly to proteins, nucleic acids, and membrane lipids. A short historical outline of research on extreme dehydration of living organisms and the current state of research are presented. Terminological issues are outlined. The role of water in the cell and the mechanisms of damage occurring in the cell under the desiccation stress are briefly discussed. Particular attention was paid to damage to proteins, nucleic acids, and membrane lipids. Understanding the nature of the changes and damage associated with desiccation is essential for the study of desiccation-tolerance mechanisms and application research. Difficulties related to the definition of life and the limits of life in the scientific discussion, caused by the phenomenon of anhydrobiosis, were also indicated.

Recently, the up-converting (UC) materials, containing lanthanide ions (Ln 3+ )have attracted considerable attention because of the multitude of their potential applications. The most frequently investigated are UC systems based on the absorption of near-infrared (NIR) radiation by Yb 3+ ions at around 975-980 nm and emission of co-dopants, usually Ho 3+ , Er 3+ or Tm 3+ ions. UC can be observed also upon excitation with irradiation with a wavelength different than around 980 nm. The most often studied systems capable of UC without the use of Yb 3+ ion are those based on the properties of Er 3+ ions, which show luminescence resulting from the excitation at 808 or 1532 nm. However, also other Ln 3+ ions are worth attention. Herein, we focus on the investigation of the UC phenomenon in the materials doped with Ho 3+ ions, which reveal unique optical properties upon the NIR irradiation. The SrF 2 NPs doped with Ho 3+ ions in concentrations from 4.9% to 22.5%, were synthesized by using the hydrothermal method. The structural and optical characteristics of the obtained SrF 2 :Ho 3+ NPs are presented. The prepared samples had crystalline structure, were built of NPs of round shapes and their sizes ranged from 16.4 to 82.3 nm. The NPs formed stable colloids in water. Under 1156 nm excitation, SrF 2 :Ho 3+ NPs showed intense UC emission, wherein the brightest luminescence was recorded for the SrF 2 :10.0%Ho 3+ compound. The analysis of the measured lifetime profiles and dependencies of the integral luminescence intensities on the laser energy allowed proposing the mechanism, responsible for the observed UC emission. It is worth mentioning that the described SrF 2 :Ho 3+ samples are one of the first materials for which the UC luminescence induced by 1156 nm excitation was obtained., (Creative Commons Attribution license.)

The synthesis of upconverting nanoparticles (NPs) is crucial for their spectroscopic properties and further applications. Reducing the size of materials to nano-dimensions usually decreases emission intensity. Therefore, scientists around the world are trying to improve the methods of obtaining NPs to approach levels of emission intensity similar to their bulk counterparts. In this article, the effects of stearic acid on the synthesis of core@shell β-NaYF 4 : 18%Yb 3+ , 2%Er 3+ @β-NaYF 4 upconverting NPs were thoroughly investigated and presented. Using a mixture of stearic acid (SA) with oleic acid and 1-octadecene as components of the reaction medium leads to the obtaining of monodispersed NPs with enhanced emission intensity when irradiated with 975 nm laser wavelength, as compared with NPs prepared analogously but without SA. This article also reports how the addition of SA influences the structural properties of core@shell NPs and reaction time. The presence of SA in the reaction medium accelerates the growth of NPs in comparison with the analogic reaction but without SA. In addition, transmission electron microscopy studies reveal an additional effect of the presence of SA on the surface of NPs, which is to cause their self-organization due to steric effects.

The right choice of synthesis route for upconverting nanoparticles (UCNPs) is crucial for obtaining a well-defined product with a specific application capability. Thus we decided to compare the physicochemical, cytotoxic, and temperature-sensing properties of UCNPs obtained from different rare earth (RE) ions, which has been made for the first time in a single study. The core/shell NaYF 4 :Yb 3+ ,Er 3+ /NaYF 4 UCNPs were obtained by reaction in a mixture of oleic acid and octadecene, and their highly stable water colloids were prepared using the ligand-free modification method. Both oleate-capped and ligand-free UCNPs exhibited a bright upconversion emission upon 975 nm excitation. Moreover, slope values, emission quantum yields, and luminescence lifetimes confirmed an effective energy transfer between the Yb 3+ and Er 3+ ions. Additionally, the water colloids of the UCNPs showed temperature-sensing properties with a good thermal sensitivity level, higher than 1 % K -1 at 358 K. Evaluation of the cytotoxicity profiles of the obtained products indicated that cell viability was decreased in a dose-dependent manner in the analyzed concentration range., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Water-dispersible up-converting nanoparticles (UCNPs) are known to be very effective in biomedical applications. Research groups have paid special attention to the synthesis of hydrophilic UCNPs with good physicochemical properties. Being aware of this, we decided to improve the ligand-free modification method of OA-capped NaYF 4 :Yb 3+ ,Er 3+ /NaYF 4 UCNPs prepared by precipitation in high-boiling-point solvents as the thus-far reported methods do not provide satisfactory results. Different molarities of hydrochloric acid and various mixing times were selected to remove the organic ligand from the NPs' surface and to discover the most promising modification approach. Highly water-stable colloids were obtained with a very high reaction yield of up to 96%. Moreover, the acid treatment did not affect the morphology and the size of the product. All of the crystals exhibited a bright up-conversion emission under 975-nm excitation, which confirmed the two-photon excitation and effective energy transfer between the used dopant ions. Thus, we could establish the most successful ligand-free modification procedure., (© 2021. The Author(s).)

The study provides deep insight into the origin of photocatalytic deactivation of Nb 2 O 5 after modification with ceria. Of particular interest was to fully understand the role of ceria species in diminishing the photocatalytic performance of CeO 2 /Nb 2 O 5 heterostructures. For this purpose, ceria was loaded on niobia surfaces by wet impregnation. The as-prepared materials were characterized by powder X-ray diffraction, nitrogen physisorption, UV-visible spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and photoluminescence measurements. Photocatalytic activity of parent metal oxides (i.e., Nb 2 O 5 and CeO 2 ) and as-prepared CeO 2 /Nb 2 O 5 heterostructures with different ceria loadings were tested in methanol photooxidation, a model gas-phase reaction. Deep insight into the photocatalytic process provided by operando -IR techniques combined with results of photoluminescence studies revealed that deactivation of CeO 2 /Nb 2 O 5 heterostructures resulted from increased recombination of photo-excited electrons and holes. The main factor contributing to more efficient recombination of the charge carriers in the heterostructures was the ultrafine size of the ceria species. The presence of such highly dispersed ceria species on the niobia surface provided a strong interface between these two semiconductors, enabling efficient charge transfer from Nb 2 O 5 to CeO 2 . However, the ceria species supported on niobia exhibited a high defect site concentration, which acted as highly active recombination centers for the photo-induced charge carriers., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Nanoparticles (NPs) based on host compound NaYF 4 with core@shell structures were synthesised by the precipitation reaction in high-boiling point octadecene/oleic acid solvent. Four laser wavelengths were used (808, 975, 1208, or 1532 nm) for excitation of the obtained NPs. The resulting emission and mechanisms responsible for spectroscopic properties were studied in detail. Depending on NP compositions, i.e. type of doping ion (Er 3+ , Tm 3+ , or Yb 3+ ) or presence of dopants in the same or different phases, adjustable up-conversion (UC) could be obtained with emission peaks covering the visible to near-infrared range (475 to 1625 nm). The presented results demonstrated multifunctionality of the prepared NPs. NaYF 4 :2%Tm 3+ @NaYF 4 NPs exhibited emission at 700 and 1450 nm under 808 nm laser excitation or 800 and 1625 nm emission under 1208 nm laser radiation, as a result of ground- and excited-state absorption processes (GSA and ESA, respectively). However, NaYF 4 :5%Er 3+ ,2%Tm 3+ @NaYF 4 NPs showed the most interesting properties, as they can convert all studied laser wavelengths due to the absorption of Tm 3+ (808, 1208 nm) or Er 3+ ions (808, 975, 1532 nm), revealing a photon avalanche process under 1208 nm laser excitation, as well as GSA and ESA at other excitation wavelengths. The NaYF 4 :2%Tm 3+ @NaYF 4 :5%Er 3+ NPs revealed the resultant emission properties, as the dopant ions were separated within core and shell phases. The NaYF 4 :18%Yb 3+ ,2%Tm 3+ @NaYF 4 and NaYF 4 :18%Yb 3+ ,2%Tm 3+ @NaYF 4 :5%Er 3+ samples showed the brightest emission, around 800 nm, under 975 nm excitation, though other laser wavelengths allowed for observation of luminescence, as well, especially in NPs with Er 3+ in the outer shell, capable of UC under 1532 nm. The presented results highlight the unique and universal properties of lanthanide ions for designing luminescent NPs for a variety of potential applications, such as confocal microscopy.

Among social influence techniques, a special place is occupied by dialogue involvement - it is not only a means of improving chances for compliance, but it can also perform a synergistic function, reinforcing the workings of other influence techniques. In two field experiments, we explored what effectiveness the technique of dialogue involvement can have in acquiring volunteers (Study 1) and how it functions in combination with the labeling technique (Study 2). The achieved results demonstrate that dialogue involvement not only increases the chance of obtaining agreement to be a volunteer in a day room facility for children or in a pediatric ward of a local hospital, but it also increases the average number of hours that volunteers declare they will work. Dialogue involvement also demonstrates effectiveness in combination with the technique of labeling.

Due to their photon up-converting capability, lanthanide ions are ideal candidates dopants for semiconductors for developing visible light-driven photocatalytic activity. Of particular relevance, the low luminescence efficiency of Ln-based nanoparticles is one of the main factors that limits their further applications. Carbon, which is present on the surface of all TiO 2 photocatalysts, can be responsible for luminescence quenching processes and, thus, decreasing the photocatalytic activity of TiO 2 . This article presents a systematic experimental and theoretical study of the effects of carbon on the photocatalytic performance of Ho 3+ -modified TiO 2 . Ho 3+ -TiO 2 photocatalysts modified with various carbon contents (from 0.5 to 20 mol.%) were successfully prepared using a simple hydrothermal method. As-obtained samples were characterized by UV-Vis diffuse reflectance spectroscopy (DRS/UV-Vis), X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), N 2 adsorption measurements, photoluminescent spectroscopy (PL), field-emission scanning electron microscopy (FE-SEM) and scanning transmission microscopy (STEM). The photodegradation efficiency of phenol was estimated for visible light (λ > 420 nm and λ > 455 nm). The XPS and XRD analyses and theoretical calculations revealed that the substitutional doping of holmium and carbon in the TiO 2 anatase structure resulted in the appearance of a new sub-band-gap. Changes in the material texture, BET surface area and pore volume can be easily controlled via carbon content in samples. Doping of the Ho 3+ -TiO 2 photocatalysts with carbon resulted in quenching of the emission of Ho 3+ and, thus, the photodegradation of phenol, was observed in samples containing smaller amounts of carbon. Sixty minutes of irradiation resulted in 89% of phenol degradation under visible light (λ > 420 nm)., (Copyright © 2019 Elsevier Inc. All rights reserved.)

For a number of years nanomaterials have been continuously devised and comprehensively investigated because of the growing demand for them and their multifarious applications, especially in medicine. This paper reports on the properties of SrF 2 nanoparticles (NPs) for applications in biomedicine, showing effective ways of their synthesis and luminescence under near infrared radiation - upconversion. NPs doped with lanthanide, Ln 3+ ions (where Ln = Yb, Ho, Er, Tm) were prepared by the hydrothermal method and subjected to comprehensive studies, from determination of their structure and morphology, revealing small, 15 nm structures, through spectroscopic properties, to cytotoxicity in vitro. The effects of such factors as the reaction time, type and amount of precipitating compounds and complexing agents on the properties of products were characterized. The cytotoxicity of the synthesized and functionalized NPs was investigated, using human fibroblast cell line (MSU-1.1). The synthesized structures may decrease cells' proliferation in a dose-dependent manner in the measured concentration range (up to 100 µg/mL). However, the cells remain alive according to the fluorescent assay. Moreover, the treated cells were imaged using confocal laser scanning microscopy. Cellular uptake was confirmed by the presence of upconversion luminescence in the cells.

We hypothesised that the question-behaviour effect, referred to as the influence of questioning about a given behaviour on its subsequent performance, is a relevant issue when exploring the external validity of intergroup attitudes. In a pair of studies, we have corroborated that merely expressing attitudes towards the Jewish minority affects people's relevant behaviour towards this group. In an Internet study, participants who first completed verbal attitude measures were more likely to donate to a Jewish organisation compared to those who completed the measures after making the decision to donate. Moreover, responses to attitude measures of various types and donating to the Jewish organisation were correlated when attitudes had been expressed in the first step. When attitudes were measured after the decision to donate, only the responses to the traditional anti-Semitic scale were correlated with this behaviour. In the field study, in which the time interval between attitude and behaviour measures was introduced, no question-behaviour effect was observed. We explain the results with reference to cognitive dissonance and attitude accessibility mechanisms and discuss them in a broader context of attitude-behaviour research., (© 2017 International Union of Psychological Science.)

The Milgram experiments are among the most well-known and important in the history of psychology. Since first published, there have been countless discussions held on the subject of what factors induce people to exhibit extreme obedience towards authority. One such potential factor, not yet explored empirically, is the receipt in advance of financial gratification by a study participant. In our experiment we compare obedience among participants in classic Milgram paradigm conditions with obedience in a situation where the participant does not receive financial gratification in advance. The results did not show that obedience differed in the two comparable situations. In conditions where the participants were not given money up front, however, it was necessary to employ more verbal prompts in order to induce obedience.

Considering the large number of adverts inundating the average consumer every day, the marketing industry is seeking methods to reach clients in a more subtle manner than traditional marketing messages. One such tool is product placement. The article addresses issues of effectiveness of product placement in comparison to a traditional commercial. The objective of the study was to check how participants would recall the content of persuasive messages in conditions of artificially inducted cognitive load (in conditions of traditional advertisement and product placement). Two studies were conducted - a pre-study intended to assess the usefulness of the selected stimuli, and the main experiment. The experiment devoted to this question was planned using an ANOVA scheme 2 (Type of advert: traditional vs. product placement) × 2 (neutral conditions vs. cognitive load). It turned out that the commercial was better retained in neutral conditions than in conditions of cognitive load. The traditional commercial was remembered better than product placement. From the perspective of the study's ecological validity, of importance is also comparison of retention of brands viewed in a traditional commercial in conditions of cognitive load with retention of brands in conditions of product placement without load. These comparisons indicate the superiority of product placement - brands presented in this manner were more frequently recalled by viewers.

Ultrasmall (9-30 nm) Yb 3+ /Er 3+ -doped, upconverting alkaline rare-earth fluorides that are promising for future applications were synthesized by the microwave-assisted hydrothermal method. The formation mechanism was proposed, indicating the influence of the stability of metal ions complexes with ethylenediaminetetraacetic acid on the composition of the product and tendency to form M 2 REF 7 (M 0.67 RE 0.33 F 2.33 ) cubic compounds in the M-RE-F systems. Their physicochemical properties (structure, morphology, and spectroscopic properties) are compared and discussed. The obtained nanoparticles exhibited emission of light in the visible spectra under excitation by 976 nm laser radiation. Excitation and emission spectra, luminescence decays, laser energy dependencies, and upconversion quantum yields were measured to determine the spectroscopic properties of prepared materials. The Yb 3+ /Er 3+ pair of ions used as dopants was responsible for an intense yellowish-green emission. The upconversion quantum yields determined for the first time for M 2 REF 7 -based materials were 0.0192 ± 0.001% and 0.0176 ± 0.001% for Sr 2 LuF 7 :Yb 3+ ,Er 3+ and Ba 2 LuF 7 :Yb 3+ ,Er 3+ respectively, the two best emitting samples. These results indicated the prepared materials are good and promising alternatives for the most studied NaYF 4 :Yb 3+ ,Er 3+ nanoparticles.

Upconversion luminescence of nano-sized Yb 3+ and Tm 3+ codoped rare earth phosphates, that is, LaPO 4 and YPO 4 , has been investigated under high-pressure (HP, up to ∼25 GPa) and high-temperature (293-773 K) conditions. The pressure-dependent luminescence properties of the nanocrystals, that is, energy red shift of the band centroids, changes of the band ratios, shortening of upconversion lifetimes, and so forth, make the studied nanomaterials suitable for optical pressure sensing in nanomanometry. Furthermore, thanks to the large energy difference (∼1800 cm -1 ), the thermalized states of Tm 3+ ions are spectrally well-separated, providing high-temperature resolution, required in optical nanothermometry. The temperature of the system containing such active nanomaterials can be determined on the basis of the thermally induced changes of the Tm 3+ band ratio ( 3 F 2,3 → 3 H 6 / 3 H 4 → 3 H 6 ), observed in the emission spectra. The advantage of such upconverting optical sensors is the use of near-infrared light, which is highly penetrable for many materials. The investigated nanomanometers/nanothermometers have been successfully applied, as a proof-of-concept of a novel bimodal optical gauge, for the determination of the temperature of the heated system (473 K), which was simultaneously compressed under HP (1.5 and 5 GPa).

Nd-modified TiO 2 photocatalysts have been obtained via hydrothermal (HT) and sol-hydrothermal (SHT) methods. The as-prepared samples were characterized by X-ray diffraction (XRD), BET surface area measurements, scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), luminescence spectroscopy and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the synthesized samples was evaluated by the degradation of phenol in aqueous solution under irradiation with UV-vis (λ > 350 nm) and vis (λ > 420 nm) light, as well as by the degradation of gaseous toluene under irradiation with vis (λ max = 415 nm) light. It was found that Nd-modified TiO 2 is an efficient photocatalyst for the degradation of phenol and toluene under visible light. XPS analysis revealed that the photocatalyst prepared via HT method contains a three-times higher amount of hydroxy groups at the surface layer and a two-times higher amount of surface defects than that obtained by the SHT method. The photocatalytic efficiency of phenol and toluene degradation under vis irradiation in the presence of 0.25% Nd-TiO 2 (HT) reached 0.62 and 3.36 μmol·dm -1 ·min -1 , respectively. Photocatalytic activity tests in the presence of Nd-TiO 2 and scavenger confirm that superoxide radicals were responsible for the visible light-induced degradation of the model pollutant in aqueous solution.

Anti-Stokes luminescence of up-converting nanocrystals SrF 2 :Yb 3+ ,Er 3+ can be used as a high pressure optical sensor alternative to the ruby fluorescence-scale. In nanocrystalline SrF 2 :Yb 3+ ,Er 3+ , high pressure reversibly shortens the emission lifetimes nearly linearly up to 5.29 GPa at least. Its advantage is the use of NIR (≈980 nm) radiation, highly penetrable for many materials. The shortening of up-conversion lifetimes has been attributed mainly to the changes in energy transfer rates, caused by decreased interatomic distances and increased overlap integrals between 4f electrons and the valence shells of ligand ions. The origin of high-pressure effects on the luminescence intensity, band ratio and their spectral position has been explained by the increased interactions and distortions of the crystal-field symmetry around the emitting ions in the compressed structure.

The article presents studies examining whether the better than average (BTA) effect appears in opinions regarding obedience of individuals participating in an experiment conducted in the Milgram paradigm. Participants are presented with a detailed description of the experiment, asked to declare at what moment an average participant would cease their participation in the study, and then asked to declare at what moment they themselves would quit the experiment. It turned out that the participants demonstrated a strong BTA effect. This effect also concerned those who had known the results of the Milgram experiment prior to the study. Interestingly, those individuals-in contrast to naive participants-judged that the average person would remain obedient for longer, but at the same time prior familiarity with the Milgram experiment did not impact convictions as to own obedience. By the same token, the BTA effect size was larger among those who had previously heard of the Milgram experiment than those who had not. Additionally, study participants were asked to estimate the behavior of the average resident of their country (Poland), as well as of average residents of several other European countries. It turned out that in participants' judgment the average Pole would withdraw from the experiment quicker than the average Russian and average German, but later than average residents of France and England.

In an experiment conducted within the Milgram paradigm, it was examined whether obedience towards an authority would be reduced in conditions in which the teacher had grounds to fear revenge from the learner. A comparison was made of the behaviour of participants in classic conditions and in conditions in which they were told that following the first part of the experiment, there would be an alteration of roles: the teacher would become the learner. It turned out that the level of compliance was the same in both groups. The dominant behaviour, regardless of whether the participant expects a change of roles or not, is total obedience.