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In this work, we unveil the fluorescence features of citric acid and urea-based Carbon Dots (CDs) through a photo-physical characterization of nanoparticles synthesized, under solvent-free and open-air conditions, within silica-ordered mesoporous silica, as a potential host for solid-state emitting hybrids. Compared to CDs synthesized without silica matrices and dispersed in water, silica-CD hybrids display a broader emission in the green range whose contribution can be increased by UV and blue laser irradiation. The analysis of hybrids synthesized within different silica (MCM-48 and SBA-15) calls for an active role of the matrix in directing the synthesis toward the formation of CDs with a larger content of graphitic N and imidic groups at the expense of N-pyridinic molecules. As a result, CDs tuned in size and with a larger green emission are obtained in the hybrids and are retained once extracted from the silica matrix and dispersed in water. The kinetics of the photo-physics under UV and blue irradiation of hybrid samples show a photo-assisted formation process leading to a further increase of the relative contribution of the green emission, not observed in the water-dispersed reference samples, suggesting that the porous matrix is involved also in the photo-activated process. Finally, we carried out DFT and TD-DFT calculations on the interaction of silica with selected models of CD emitting centers, like surface functional groups (OH and COOH), dopants (graphitic N), and citric acid-based molecules. The combined experimental and theoretical results clearly indicate the presence of molecular species and surface centers both emitting in the blue and green spectral range, whose relative contribution is tuned by the interaction with the surrounding media.

A general strategy for the synthesis of 2-substituted cyclobutanone sulfides via a tandem Brønsted acid-catalyzed nucleophile addition/ring contraction/C3-C4 ring expansion reaction sequence has been exploited. The procedure led to a wide panel of four-membered cyclic ketones in good to excellent yields and with broad substrate scope. Mechanistic aspects and kinetic parameters were investigated by quantum chemical DFT calculations, allowing us to rationalize the different reactivity of 2-aryl- and 2-alkyl-substituted 2-hydroxycyclobutanones towards thiol nucleophiles in reactions mediated by sulfonic acids. NMR and in situ Raman techniques were employed to better understand the reaction kinetics and parameters that affect the desired outcome.

The differences between bare carbon dots (CDs) and nitrogen-doped CDs synthesized from citric acid as a precursor are investigated, aiming at understanding the mechanisms of emission and the role of the doping atoms in shaping the optical properties. Despite their appealing emissive features, the origin of the peculiar excitation-dependent luminescence in doped CDs is still debated and intensively being examined. This study focuses on the identification of intrinsic and extrinsic emissive centers by using a multi-technique experimental approach and computational chemistry simulations. As compared to bare CDs, nitrogen doping causes the decrease in the relative content of O-containing functional groups and the formation of both N-related molecular and surface centers that enhance the quantum yield of the material. The optical analysis suggests that the main emission in undoped nanoparticles comes from low-efficient blue centers bonded to the carbogenic core, eventually with surface-attached carbonyl groups, the contribution in the green range being possibly related to larger aromatic domains. On the other hand, the emission features of N-doped CDs are mainly due to the presence of N-related molecules, with the computed absorption transitions calling for imidic rings fused to the carbogenic core as the potential structures for the emission in the green range.

A series of 6-aryl coumarin dyes were synthesized in satisfactory yields by Pd-catalyzed Suzuki cross-coupling reactions with a panel of boronic acids and coumarin bromides. Photophysical studies highlighted a large Stoke shift and interesting fluorescence quantum yield for these compounds. Optical properties were also investigated with the aid of quantum chemical calculations. The treatment of selected coumarin dyes with increasing amounts of trifluoroacetic acid showed that their fluorescence can be strongly influenced by pH (fluorescence quenching at high acid concentrations), while the addition of Fe3+ and Al3+ metal ions allowed to highlight dichotomous behavior with the corresponding reduction in fluorescence with the increase of [Fe3+] or [Al3+]. Finally, biological assays and fluorescence microscopy imaging investigations indicated that these compounds can be used as potential biomarkers in living and fixed cells.

We compared two technology configurations (relying on a smartphone, indoor motion sensors, and mini speakers) for helping people with intellectual disability and visual impairments independently manage functional occupational engagement. One of the configurations (a) provided a verbal instruction for each of the objects the participant was to collect within every session, (b) delivered auditory spatial cues to guide the participant to the area where the object could be found, and (c) repeated the instruction once the area was reached. The other configuration differed in that it did not involve any instruction repetition once the participant had reached the area with the object to collect. Six participants used both technology configurations with two or three pairs of activities. One activity of each pair was carried out using the configuration with instruction repetition while the other was carried out using the configuration without instruction repetition, according to an alternating treatments design with a crossover phase. The mean frequency of correct responses with the configuration involving instruction repetition (a) exceeded 17.6 (out of a maximum possible of 18) for all participants, and (b) was significantly higher than the mean frequency obtained with the configuration without instruction repetition. The configuration with instruction repetition may be an effective tool for supporting functional occupation of people with intellectual disability and visual impairments.

Abstract Objectives This study assessed a new technology system that automatically presented instructions for multistep activities to people with intellectual and sensory disabilities. The instructions were presented one at a time, and tied to the participants’ performance of the activity steps. That is, a new instruction occurred only after the participant had carried out the previous step. Methods The new system involved a Samsung Galaxy A10 with Android 10.0 operating system equipped with Amazon Alexa, MacroDroid, and Philips Hue applications and a Philips Hue indoor motion sensor. The assessment of the new system was carried out with seven participants who were exposed to two or three pairs of activities. They performed one activity of each pair with the new system and the other with a system presenting instructions at preset time intervals according to an alternating treatments design that included a cross-over phase. Results The mean percentage of correct responses tended to be higher with the new system than with the control system. Paired t-tests carried out to compare the sessions with the new system with the sessions with the control system of each participant showed that the differences in correct responses between the two sets of sessions were statistically significant for all participants. Conclusions The new system may represent a useful (advantageous) tool for supporting people like those involved in this study in the performance of multistep activities.

Heterogeneous photocatalysts have garnered extensive attention as a sustainable way for environmental remediation and energy storage process. Water splitting, solar energy conversion, and pollutant degradation are examples of nowadays applications where semiconductor-based photocatalysts represent a potentially disruptive technology. The exploitation of solar radiation for photocatalysis could generate a strong impact by decreasing the energy demand and simultaneously mitigating the impact of anthropogenic pollutants. However, most of the actual photocatalysts work only on energy radiation in the Near-UV region (

Cadmium yellow degradation afflicts numerous paintings realized between the XIXth and XXth centuries. The degradation process and its kinetics is not completely understood. It consists of chalking, lightening, flaking, spalling, and, in its most deteriorated cases, the formation of a crust over the original yellow paint. In order to improve the comprehension of the process, mock-up samples of CdS in yellow and orange tonalities were studied by means of structural analysis and optical characterization, with the principal techniques used in the field of cultural heritage. Mock ups were artificially degraded with heat treatment and UV exposure. Relevant colorimetric variation appears in CIE Lab coordinates from reflectance spectra. XRD, SEM-EDS, and Raman spectroscopy revealed the formation of cadmium sulfate, whilst time-resolved photoluminescence and pump–probe transient absorption spectroscopy suggest the formation of a defective phase, compatible with Cd vacancies and the formation of both CdO and CdSO4 superficial clusters.

The need to find a rapid and worthwhile technique for the in situ detection of the content of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in

Recent developments in lighting and display technologies have led to an increased focus on materials and phosphors with high efficiency, chemical stability, and eco-friendliness. Mechanoluminescence (ML) is a promising technology for new lighting devices, specifically in pressure sensors and displays. CaZnOS has been identified as an efficient ML material, with potential applications as a stress sensor. This study focuses on optimizing the mechanoluminescent properties of CaZnOS:Tb through microwave-assisted synthesis. We successfully synthesized CaZnOS doped with Tb3+ using this method and compared it with samples obtained through conventional solid-state methods. We analyzed the material’s characteristics using various techniques to investigate their structural, morphological, and optical properties. We then studied the material’s mechanoluminescent properties through single impacts with varying energies. Our results show that materials synthesized through microwave methods exhibit similar optical and, primarily, mechanoluminescent properties, making them suitable for use in photonics applications. The comparison of the microwave and conventional solid-state synthesis methods highlights the potential of microwave-assisted methods to optimize the properties of mechanoluminescent materials for practical applications.

Symmetry-breaking synthetic controls allow for nanostructure geometries that are counter to the underlying crystal symmetry of a material. If suitably applied, such controls provide the means to drive an isotropic metal along a growth pathway yielding a three-dimensional chiral geometry. Herein, we present a light-driven solution-based synthesis yielding helical gold spirals from substrate-bound seeds. The devised growth mode relies on three separate symmetry-breaking events ushered in by seeds lined with planar defects, a capping agent that severely frustrates early stage growth, and the Coulombic repulsion that occurs when identically charged growth fronts collide. Together they combine to advance a growth pathway in which planar growth emanates from one side of the seed, advances to encircle the seed from both clockwise and counterclockwise directions, and then, upon collision of the two growth fronts, sees one front rise above the other to realize a self-perpetuating three-dimensional spiral structure.

The molecular emission model is the most accredited one to explain the emission properties of carbon dots (CDs) in a low-temperature bottom-up synthesis approach. In the case of citric acid and ure...

A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples, due to their typically limited time-stability, and the understanding of the role of external factors that can induce a crystal phase transformation (such as humidity, intense light flux, temperature, etc.). In this perspective, it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring. In this paper we propose Raman spectroscopy as the ideal technique to solve this problem. The vibrational analysis of CsPbI3 in the α-phase and δ-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework. Finally, the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.

A novel blue excitable green fluorescent triazine-based material with high thermal stability (up to 350 °C) has been synthesized. Solid-state structural characterizations showed bright solid-state photoluminescence centered at 490 nm with an internal quantum yield (iQY) up to 40%. The coordination capabilities offered by the presence of a multi nitrogen and oxygen heteroatom framework allows to use TABNO (4,4′,4′′,4′′′-((6,6′-oxybis(1,3,5-triazine-6,4,2-triyl))tetrakis(azanediyl))tetrabenzonitrile) as Tb3+ and Eu3+ photosensitizer, thus delivering a purely organic host matrix for Ln ions with tunable light emissions. Blending this new material with K2SiF6:Mn4+ allowed access to a new class of REE free NUV-blue excitable warm light-emitting phosphors.

Undoped and Zr-doped BaTiO powders have been prepared by self-propagating combustion synthesis from suitable precursors. The obtained powders have been subjected to thermal annealing in air at temperatures between 400 and 1200 °C. Experimental findings indicate that annealing affects compositional, structural and optical properties. XRD analysis reveals the presence of a metastable hexagonal phase in powders obtained by SHS. Its relative amount drastically decreases during high-temperature annealing. As-synthesized powders have broad photoluminescence due to the degree of structural order in the powders. This can be also seen from the absorbance spectra, which exhibit a band at 650 nm. F color centers form as a consequence of electron trapping in oxygen vacancies.

Citrazinic acid (CZA) is a weakly fluorescent molecular compound whose optical properties are dependent on aggregation states and chemical environment. This molecule and its derivatives have been recently identified as the source of the intense blue emission of carbon dots obtained from citric acid with a nitrogen source, such as ammonia or urea. Citrazinic acid has a strong tendency to aggregate and form tautomers whose optical properties are largely unexplored. At extreme acidic and basic pH values, we have observed an “anomalous” optical response of citrazinic acid, attributed to the formation of aggregates from the tautomers. We have characterized the molecule, both at pH = 1 and 14, using UV–vis, NMR, steady-state, and time-resolved fluorescence spectroscopy. At extremely low pH values, the protonation causes luminescence quenching and the appearance of new emissions. On the contrary, high pH values are responsible for deprotonation and splitting of the excitation spectra.

Highly fluorescent blue and green-emitting carbon dots have been designed to be integrated into sol-gel processing of hybrid organic-inorganic materials through surface modification with an organosilane, 3-(aminopropyl)triethoxysilane (APTES). The carbon dots have been synthesised using citric acid and urea as precursors; the intense fluorescence exhibited by the nanoparticles, among the highest reported in the scientific literature, has been stabilised against quenching by APTES. When the modification is carried out in an aqueous solution, it leads to the formation of silica around the C-dots and an increase of luminescence, but also to the formation of large clusters which do not allow the deposition of optically transparent films. On the contrary, when the C-dots are modified in ethanol, the APTES improves the stability in the precursor sol even if any passivating thin silica shell does not form. Hybrid films containing APTES-functionalized C-dots are transparent with no traces of C-dots aggregation and show an intense luminescence in the blue and green range.

CsPbI3 inorganic perovskite is synthesized by a solvent-free, solid-state reaction, and its structural and optical properties can be deeply investigated using a multi-technique approach. X-ray Diffraction (XRD) and Raman measurements, optical absorption, steady-time and time-resolved luminescence, as well as High-Resolution Transmission Electron Microscopy (HRTEM) imaging, were exploited to understand phase evolution as a function of synthesis time length. Nanoparticles with multiple, well-defined crystalline domains of different crystalline phases were observed, usually surrounded by a thin, amorphous/out-of-axis shell. By increasing the synthesis time length, in addition to the pure α phase, which was rapidly converted into the δ phase at room temperature, a secondary phase, Cs4PbI6, was observed, together with the 715 nm-emitting γ phase.

Our qualitative study sought to illuminate via examination the behaviour of Teachers in the classroom, with a focus on verbal abuse. This was accomplished by reviewing a sample of the decisions of the discipline committee of the Ontario College of Teachers (OCT). Data were collected from the Canadian Legal Information Institute (CANLII) online database, which provided a record of all the OCT discipline committee decisions, with supplementary data from Professionally Speaking, the magazine of the OCT, as well as the OCT’s website. Data revealed that verbal abuse is ongoing and omnipresent in Ontario classrooms, and that our measured response and related methods of dealing with teacher misconduct are derisory at best and slowly evolving. Investigated cases of verbal abuse in the classroom were reviewed and illuminated the progress that has been made in dealing with Teacher verbal abuse in schools, while providing suggestions for improvement. Male Teachers are often offenders and the impact on all stakeholders is both life-changing and serious we have discovered. Overall, we concluded, that the delay in effectively dealing with complaints and disciplinary matters is unacceptable as it stands, and must be fixed in order to protect a greater number of students from abuse.

The purpose of this work was the assembly of multicomponent nano-bioconjugates based on mesoporous silica nanoparticles (MSNs), proteins (bovine serum albumin, BSA, or lysozyme, LYZ), and gold nanoparticles (GNPs). These nano-bioconjugates may find applications in nanomedicine as theranostic devices. Indeed, MSNs can act as drug carriers, proteins stabilize MSNs within the bloodstream, or may have therapeutic or targeting functions. Finally, GNPs can either be used as contrast agents for imaging or for photothermal therapy. Here, amino-functionalized MSNs (MSN–NH2) were synthesized and characterized through various techniques (small angle X-rays scattering TEM, N2 adsorption/desorption isotherms, and thermogravimetric analysis (TGA)). BSA or lysozyme were then grafted on the external surface of MSN–NH2 to obtain MSN–BSA and MSN–LYZ bioconjugates, respectively. Protein immobilization on MSNs surface was confirmed by Fourier transform infrared spectroscopy, ζ-potential measurements, and TGA, which also allowed the estimation of protein loading. The MSN–protein samples were then dispersed in a GNP solution to obtain MSN–protein–GNPs nano-bioconjugates. Transmission electron microscopy (TEM) analysis showed the occurrence of GNPs on the MSN–protein surface, whereas almost no GNPs occurred in the protein-free control samples. Fluorescence and Raman spectroscopies suggested that proteins–GNP interactions involve tryptophan residues.

The development of new luminescent materials for lighting applications or stress sensors, mechano-driven lighting devices is a crucial technological topic. Materials suitable for these applications should guarantee a high chemical stability, easiness and green sintering procedure and optimal optical properties. In this framework Calcium Zinc oxysulfide (CaZnOS) represents one of the most promising materials, for its near UV excitation with a broad visible emission, a long phosphorescence and a mechano-luminescence effect that still need to be explored. In this work we report the optical properties and the kinetics of radiative recombination upon intrinsic and extrinsic excitation of pure CaZnOS, assessing the vibrational properties by means of Raman spectroscopy, and corroborated by DFT calculations. The analysis of time resolved measurements at room and low temperature (up to 10 K) give new insight on the distribution and nature of the defects that generate the luminescence upon external stress as well the long phosphorescence. Herein, we also present a model of the intrinsic defects and on the energy transfer mechanism among levels in pure CaZnOS matrix, opening new perspectives also on doped materials and for the development of piezoluminescent devices.

A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.

Aqueous copper redox flow batteries (CuRFB) based systems offer an alternative, more sustainable, redox flow battery to those based on vanadium for stationary renewable energy storage. Copper is an abundant material (~20 million tonnes/ year), that can be easily recycled and is significantly lower cost (6.5 € kg -1), by comparison with vanadium technology (20 € kg-1)[i]. CuRFBs can also be operated without perfluorinated membranes required in the vanadium redox flow batteries (VRFB). The CuRFB system takes advantage of the three stable oxidation states of copper Cu(0)-Cu(I)–Cu(II) in which the cuprous species are oxidised to cupric species in the positive half-cell and electrochemically deposited as copper on the negative electrode. The electrolyte system investigated in this work is based on chloride salts which are soluble up to 2.5 M[ii] ,[iii] . This concentration level enables high current densities to be achieved assisting with high power delivery. The present study was focussed on the electrolyte optimisation including the use of ammonium salts as an alternative to calcium salts to provide a higher conductivity chloride based electrolyte with lower overpotential and better reversibility of the copper deposition and dissolution reaction. Other smaller (mM level) quantity bismuth based chemical additives were also found to improve the coulombic efficiency of the copper deposition and dissolution reaction in extended cycling. [i] E. Sánchez-Díez, E. Ventosa, M. Guarnieri, A. Trovò, C. Flox, R. Marcilla, F. Soavi, P. Mazur, E. Aranzabe, R. Ferret, Redox flow batteries: Status and perspective towards sustainable stationary energy storage, Journal of Power Sources, 481, (2021), 228804, [ii] G. Lacarbonara, L. Faggiano, S. Porcu, P.C. Ricci, S. Rapino, D.P. Casey, J.F. Rohan, C. Arbizzani Copper chloro-complexes concentrated solutions: an electrochemical study, Batteries, 7 (2021) 83 [iii] L. Faggiano, G. Lacarbonara, W.D. Badenhorst, L. Murtomäki, L. Sanz, C. Arbizzani, Short thermal treatment of carbon felts for copper-based redox flow batteries, Journal of Power Sources, 520, (2022), 230846 Figure 1

Totally inorganic perovskites are playing an increasingly important role for their potential applications in optoelectronics devices. However, a big problem to be solved is the role of the different phases, the presence of which is closely linked to the growth method and to the role of impurities. In this article, we propose a solvent-free, solid-state growth method, which allows to obtain samples free of any organic residues. The analysis of structural (XRD and Raman measurements), optical (absorption, steady-time and time-resolved luminescence) and morphological (HRTEM imaging), permitted to understand the phase evolution during the synthesis as a function of the temporal duration. The dynamic equilibrium process at high temperature between the CsPbI3 and the starting precursors, CsI and PbI2, plays a fundamental role in the final phase. If, from one side, the α and δ phases are related to the exact stoichiometry, on the other hand an excess of CsI permits the formation of room temperature stable perovskite γ-phase and, with a further excess, the secondary Cs4PbI6 phase is obtained.

The molecular model is one of the most appealing to explain the peculiar optical properties of Carbon nanodots (CNDs) and was proven to be successful for the bottom up synthesis, where a few molecules were recognized. Among the others, citrazinic acid is relevant for the synthesis of citric acid-based CNDs. Here we report a combined experimental and computational approach to discuss the formation of different protonated and deprotonated species of citrazinic acid and their contribution to vibrational and magnetic spectra. By computing the free energy formation in water solution, we selected the most favoured species and we retrieved their presence in the experimental surface enhanced Raman spectra. As well, the chemical shifts are discussed in terms of tautomers and rotamers of most favoured species. The expected formation of protonated and de-protonated citrazinic acid ions under extreme pH conditions was proven by evaluating specific interactions with H2SO4 and NaOH molecules. The reported results confirm that the presence of citrazinic acid and its ionic forms should be considered in the interpretation of the spectroscopic features of CNDs.

The authors share that they have no doubt that mainstream schooling wounds people deeply. From a holistic framework, people within mainstream schooling experience stresses to their mind, body, spirit, and emotions. Their souls are under siege as they are controlled, judged, manipulated, and oppressed. It is said of mainstream schooling that it creates opportunities, the authors say that it limits opportunities. People within mainstream schooling experience fear and anxiety, and fear and anxiety are not conducive to learning, rather they diminishes learning. In what follows, Brooke and Debbie will share their stories of how they found willed learning and what that has meant to them and their children. Their story is informed by Carlo Ricci's framework of willed learning.

Halide perovskite colloidal nanocrystals have recently gained much attention thanks to their superior stability compared with their bulk counterpart and to their unique optical properties. In this paper, two systems combining nanocrystals and nanoporous gold are studied to create an optimal metal semiconductor heterojunction that can be used in photocatalysis and photovoltaic devices. The perovskite degradation phenomenon is observed when the nanoporous gold powder is mixed into the hexane suspension of nanocrystals, while the charge separation efficiency is increased by synthesizing the nanocrystals directly onto the gold porous structure. The analysis of the structural and optical properties evidences an energy transfer efficiency of 47%, along with the high structural stability of the hybrid system.

International audience; The mechanochemical preparation of silver sulfadiazine and dantrolene, two marketed active pharmaceutical ingredients, was investigated by in situ Raman spectroscopy. For the first time, the mechanochemical transformations involving highly fluorescent compounds could be studied in situ with a high-resolution Raman system combined with a unique suitable Raman probe. Moreover, the kinetic features of the mechanochemical process were examined by a mathematical model allowing to describe the chemical changes under mechanical stress. This approach is promising both to broaden the scope of Raman in situ investigations that would otherwise be impossible and for process optimization at any scale.

The psychologist described here had been working in the company under discussion for about two years before he joined our research team. As a result, his situation in the company, by all accounts, could no longer be changed. Moreover, even before his appointment, he had been friendly with one of the two owners. Our account of the workings of the company reconstructs the interventions our team suggested to the psychologist. These were proposed for two main reasons. The first was to provoke responses likely to yield information that otherwise might not be forthcoming. The second, by contrast, was the result of the group’s exasperation when it became clear that it could not influence the repetitive game of the partners. Deciding that the company was “sick” and in need of “therapy,” the group proposed its interventions.

The mechanochemical preparation of silver sulfadiazine and dantrolene, two marketed active pharmaceutical ingredients, was investigated by in situ Raman spectroscopy. For the first time, the mechanochemical transformations involving highly fluorescent compounds could be studied in situ with a high-resolution Raman system combined with a unique suitable Raman probe. Moreover, the kinetic features of the mechanochemical process were examined by a mathematical model allowing to describe the chemical changes under mechanical stress. This approach is promising both to broaden the scope of Raman in situ investigations that would otherwise be impossible and for process optimization at any scale.

Numerous experimental techniques of analysis find applications in many branches of the archaeometry. Among them, Raman spectroscopy carved out a niche in the field of diagnostic and conservation of cultural heritage. The exceptional ability to predict and discover the structural properties of materials set for Raman spectroscopy, an exclusive role among the analytic techniques, is further boosted when it is coupled with mathematical or statistical models able to deepen the studied phenomena. In this work, we present a review of recent studies where pairing Raman spectroscopy and mathematical models allowed achieving important results in the case of potteries, porcelains, ancient and modern paper, ancient jewelry, and pigment degradation. The potentialities of this approach are evidenced and analyzed in detail.

The continuous flow Norrish–Yang photocyclization of 1,2-diketones has been developed and used for the synthesis of a large number of functionalized 2-hydroxycyclobutanones, under blue light irradiation and employing acetone as a solvent. This eco-friendly procedure represents a valid alternative to the reactions carried out in batches thus reducing the reaction times, the formation of secondary products and simplifying the purification steps. The use of differently substituted diketone compounds has allowed us to obtain a wide range of 2 and 3-functionalized cyclobutanones, thus allowing the evaluation of the scope and limitations of this procedure.

Calcium hydroxide, a crystal involved in the cycle of calcination and carbonation of calcium oxide, finds several applications from cultural heritage to the dentistry branch or to the construction industry. When excited at 1064 nm, Raman spectra of calcium hydroxide show a broad composite band peaked at about 780 cm&minus, 1, corresponding to 1170 nm. Since it is not observed with visible excitation, the origin of this band is debated, being assigned to some pre-existent luminescent impurities or some structural defect of the lime formed after the synthesis of the material. To shed light on the formation of this band, we synthetised the lime paste starting from pure calcite powders. The obtained fresh Ca(OH)2 samples did not show any band in the investigated range, irrespective of the laser excitation applied. A detailed analysis of the excitation and emission spectra in the near infrared region did not show the 1170 nm band, supporting the hypothesis of a post-synthesis origin. Thus, we carried out thermal treatments at different temperatures (90&ndash, 500 &deg, C) and under different environments (in air or under nitrogen flux) on synthesised fresh Ca(OH)2 powders. We also investigated the time evolution of the samples, monitoring the Raman spectra over 90 days after a specific treatment. The collected data support the hypothesis of a defect-related luminescence centre, whose formation depends on the temperature and environment of the treatment, which appears as a preferential site for the carbonation process of the calcium hydroxide. These results can be useful in the field of Cultural Heritage for dating purposes, and to determine the conservation state of Ca(OH)2 containing relics to prevent the possible activation of degradation processes.

Applications based on aggregates of magnetic nanoparticles are becoming increasingly widespread, ranging from hyperthermia to magnetic recording. However, although some uses require collective behavior, others need a more individual-like response, the conditions leading to either of these behaviors are still poorly understood. Here, we use nanoscale-uniform binary random dense mixtures with different proportions of oxide magnetic nanoparticles with low/high anisotropy as a valuable tool to explore the crossover from individual to collective behavior. Two different anisotropy scenarios have been studied in two series of binary compacts: M1, comprising maghemite (γ-Fe2O3) nanoparticles of different sizes (9.0 nm/11.5 nm) with barely a factor of 2 between their anisotropy energies, and M2, mixing equally sized pure maghemite (low-anisotropy) and Co-doped maghemite (high-anisotropy) nanoparticles with a large difference in anisotropy energy (ratio > 8). Interestingly, while the M1 series exhibits collective behavior typical of strongly coupled dipolar systems, the M2 series presents a more complex scenario where different magnetic properties resemble either “individual-like” or “collective”, crucially emphasizing that the collective character must be ascribed to specific properties and not to the system as a whole. The strong differences between the two series offer new insight (systematically ratified by simulations) into the subtle interplay between dipolar interactions, local anisotropy and sample heterogeneity to determine the behavior of dense assemblies of magnetic nanoparticles., This work was supported by the Spanish Ministerio de Economia y Competitividad (grants MAT2015-65295-R and MAT2016-77391-R). J.N. also acknowledges funding from the Generalitat de Catalunya through the 2017-SGR-292 grant. ICN2 is funded by the CERCA Programme/Generalitat de Catalunya. The ICN2 is supported by the Severo Ochoa Centers of Excellence program, funded by the Spanish Research Agency (AEI, grant no. SEV-2017-0706). M.S.A., R.M., and P.N. acknowledge support from The Swedish Research Council (VR). K.N.T, D.P., and M.V. acknowledge support from the European Union’s Horizon 2020 Research and Innovation Programme: under grant agreement no. 731976 (MAGENTA).