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The most efficient upconversion (UC) materials reported to date are based on fluoride hosts with low phonon energies, which reduce the amount of nonradiative transitions. In particular, NaYF4 doped with Yb3+ and Er3+ at appropriate ratios is known as one of the most efficient UC phosphors. However, its low thermal stability limits its use for certain applications. On the other hand, oxide hosts exhibit better thermal stability, yet they have higher phonon energies and are thus prone to lower UC efficiencies. As a result, developing host nanomaterials that combine the robustness of oxides with the high upconversion efficiencies of fluorides remains an intriguing prospect. Herein, we demonstrate the formation of ytrrium doped oxyfluoride (YOF:Yb3+,Er3+) particles, which are prepared by growing a NaYF4:Yb3+,Er3+ layer around SiO2 spherical particles and consecutively applying a high-temperature annealing step followed by the removal of SiO2 template. Our interest lies in employing these materials as Boltzmann type physiological range luminescence thermometers, but their weak green emission is a drawback. To overcome this issue, and engineer materials suitable for Boltzmann type thermometry, we have studied the effect of introducing different metal ion co-dopants (Gd3+, Li+ or Mn2+) into the YOF:Yb3+,Er3+ particles, focusing on the overall emission intensity, as well as the green to red ratio, upon 975 nm laser excitation. These materials are explored for their use as ratiometric thermometers, and further also as drug carriers, including their simultaneous use for these two applications. The investigation also includes examining their level of toxicity towards specific human cells - normal human dermal fibroblasts (NHDFs) - to evaluate their potential use for biological applications.
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The paper presents the study concerning the preparation and physio-chemical and biological properties of wool-copper (WO-Cu) materials obtained by the sputter deposition of copper onto the wool fibers. The WO-Cu material was subjected to physio-chemical and biological investigations. The physio-chemical investigations included the elemental analysis of materials (C, N, O, S, and Cu), their microscopic analysis, and surface properties analysis (specific surface area and total pore volume). The biological investigations consisted of the antimicrobial activity tests of the WO-Cu materials against colonies of Gram-positive (Staphylococcus aureus) bacteria, Gram-negative (Escherichia coli) bacteria, and fungal mold species (Chaetomium globosum). Biochemical-hematological tests included the evaluation of the activated partial thromboplastin time and pro-thrombin time. The tested wool-copper demonstrated the ability to interact with the DNA in a time-dependent manner. These interactions led to the DNA's breaking and degradation. The antimicrobial and antifungal activities of the WO-Cu materials suggest a potential application as an antibacterial/antifungal material. Wool-copper materials may be also used as customized materials where the blood coagulation process could be well controlled through the appropriate copper content.
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Defect engineering in metal-organic frameworks (MOFs) has gained worldwide research traction, as it offers tools to tune the properties of MOFs. Herein, we report a novel 2-fold interpenetrated Bi-based MOF made of a tritopic flexible organic linker, followed by missing-linker defect engineering. This procedure creates a gradually augmented micro- and mesoporosity in the parent (originally nonporous) network. The resulting MOFs can tolerate a remarkable extent of linker vacancy (with absence of up to 60% of linkers per Bi node) created by altering the crystal-growth rate as a function of synthesis temperature and duration. Owing to the enhanced porosity and availability of the uncoordinated Lewis acidic Bi sites, the defect-engineered MOFs manifested improved surface areas, augmented CO2 and water vapor uptake, and catalytic activity. Parallel to this, the impact of defect engineering on the optoelectronic properties of these MOFs has also been studied, offering avenues for new applications.
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The paper presents the investigation of the biological properties of Poly(Lactide)-Copper composite material obtained by sputter deposition of copper onto Poly(lactide) melt-blown nonwoven fabrics. The functionalized composite material was subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, Chaetomium globosum and Candida albicans fungal mold species and biochemical-hematological tests including the evaluation of the Activated Partial Thromboplastin Time, Prothrombin Time, Thrombin Time and electron microscopy fibrin network imaging. The substantial antimicrobial and antifungal activities of the Poly(Lactide)-Copper composite suggests potential applications as an antibacterial/antifungal material. The unmodified Poly(Lactide) fabric showed accelerated human blood plasma clotting in the intrinsic pathway, while copper plating abolished this effect. Unmodified PLA itself could be used for the preparation of wound dressing materials, accelerating coagulation in the case of hemorrhages, and its modifications with the use of various metals might be applied as new customized materials where blood coagulation process could be well controlled, yielding additional anti-pathogen effects.
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This study explores the potential of combining periodic mesoporous organosilicas (PMOs) with a fluorescent dye to develop a ratiometric thermometry system with enhanced stability, sensitivity, and biocompatibility. PMOs, ordered porous materials known for their stability and versatility, serve as an ideal platform. Curcumin, a natural polyphenol and fluorescent dye, is incorporated into PMOs to develop curcumin-functionalized PMOs (C-PMO) and curcumin-pyrazole-functionalized PMOs (CP-PMO) via hydrolysis and co-condensation. These PMOs exhibit temperature-dependent fluorescence properties. The next step involves encapsulating rhodamine B (RhB) dye within the PMO pores to create dual-emitting PMO@dye nanocomposites, followed by a lipid bilayer (LB) coating to enhance biocompatibility and dye retention. Remarkably, within the physiological temperature range, C-PMO@RhB@LB and CP-PMO@RhB@LB demonstrate noteworthy maximum relative sensitivity (Sr) values of up to 1.69 and 2.60% K-1, respectively. This approach offers versatile means to create various ratiometric thermometers by incorporating different fluorescent dyes, holding promise for future temperature sensing applications.
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The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples' properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents-vaporised hydrogen peroxide, ozone or their combination-are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H2O2. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect.
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The solid-state synthesis of single-crystalline organic polymers, having functional properties, remains an attractive and developing research area in polymer chemistry and materials science. However, light-triggered topochemical synthesis of crystalline polymers comprising an organoboron backbone has not yet been reported. Here, we describe an intriguing example of single-crystal-to-single-crystal (SCSC) rapid photosynthesis (occurs on a seconds-scale) of two structurally different linear organoboron polymers, driven by environmentally sustainable visible/sun light, obtained from the same monomer molecule. A newly designed Lewis acid-base type molecular B â N organoboron adduct (consisting of an organoboron core and naphthylvinylpyridine ligands) crystallizes in two solid-state forms featuring the same chemical structure but different 3D structural topologies, namely, monomers 1 and 2. The solvate molecule-free crystals of 1 undergo topochemical photopolymerization via an unusual olefin-naphthyl ring [2 + 2] cyclization to yield the single crystalline [3]-ladderane polymer 1P growing along the B â N linkages, accompanied by instantaneous and violent macroscopic mechanical motions or photosalient effects (such as bending-reshaping and jumping motions). In contrast, visible light-harvesting single crystals of 2 quantitatively polymerize to a B â N bond-stabilized polymer 2P in a SCSC fashion owing to the rapid [2 + 2] cycloaddition reaction among olefin double bonds. Such olefin bonds in the crystals of 2 are suitably preorganized for photoreaction due to the presence of solvate molecules in the crystal packing. Single crystals of 2 also show photodynamic jumping motions - in response to visible light but in a relatively slower fashion than the crystals of 1. In addition to SCSC topochemical polymerization and dynamic motions, both monomer crystals and their single-crystalline polymers feature green emissive and short-lived room-temperature phosphorescence properties upon excitation with visible-light wavelength.
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Using a straightforward sequence of diphosphonylation and a Pd-catalysed concerted-metalation-deprotonation (CMD), a synthetic strategy towards polyaromatic phosphorus containing heterocycles was developed. Herein, we report the synthesis and characterization of new azaphosphaphenalenes, using easily accessible palladium catalysts and starting materials. The key tetrahydroquinoline intermediates of the reaction were synthesised via a fast and effective procedure and could be isolated as such, or further reacted towards the target polyaromatic structures. The obtained products showed interesting luminescent properties and their emission, excitation and quantum yields were evaluated.
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Alginate-based materials have gained significant attention in the medical industry due to their biochemical properties. In this article, we aimed to synthesize Cotton-Alginate-Copper Composite Materials (COT-Alg(-)Cu(2+)). The main purpose of this study was to assess the biochemical properties of new composites in the area of blood plasma coagulation processes, including activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT). This study also involved in vitro antimicrobial activity evaluation of materials against representative colonies of Gram-positive and Gram-negative bacteria and antifungal susceptibility tests. The materials were prepared by immersing cotton fibers in an aqueous solution of sodium alginate, followed by ionic cross-linking of alginate chains within the fibers with Cu(II) ions to yield antimicrobial activity. The results showed that the obtained cotton-alginate-copper composites were promising materials to be used in biomedical applications, e.g., wound dressing.
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Alginatos , Cobre , Cobre/química , Alginatos/química , Antibacterianos/farmacologia , Antibacterianos/química , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Coagulação Sanguínea , Tempo de Protrombina , Tempo de Tromboplastina Parcial , Íons/farmacologiaRESUMO
Flaxseed oil is one of the best sources of n-3 fatty acids, thus its adulteration with refined oils can lead to a reduction in its nutritional value and overall quality. The purpose of this study was to compare different chemometric models to detect adulteration of flaxseed oil with refined rapeseed oil (RP) using differential scanning calorimetry (DSC). Based on the melting phase transition curve, parameters such as peak temperature (T), peak height (h), and percentage of area (P) were determined for pure and adulterated flaxseed oils with an RP concentration of 5, 10, 20, 30, and 50% (w/w). Significant linear correlations (p ≤ 0.05) between the RP concentration and all DSC parameters were observed, except for parameter h1 for the first peak. In order to assess the usefulness of the DSC technique for detecting adulterations, three chemometric approaches were compared: (1) classification models (linear discriminant analysis-LDA, adaptive regression splines-MARS, support vector machine-SVM, and artificial neural networks-ANNs); (2) regression models (multiple linear regression-MLR, MARS, SVM, ANNs, and PLS); and (3) a combined model of orthogonal partial least squares discriminant analysis (OPLS-DA). With the LDA model, the highest accuracy of 99.5% in classifying the samples, followed by ANN > SVM > MARS, was achieved. Among the regression models, the ANN model showed the highest correlation between observed and predicted values (R = 0.996), while other models showed goodness of fit as following MARS > SVM > MLR. Comparing OPLS-DA and PLS methods, higher values of R2X(cum) = 0.986 and Q2 = 0.973 were observed with the PLS model than OPLS-DA. This study demonstrates the usefulness of the DSC technique and importance of an appropriate chemometric model for predicting the adulteration of cold-pressed flaxseed oil with refined rapeseed oil.
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We have synthesized a co-condensed hollow ethane-bipyridine periodic mesoporous organosilica (HEt-bpy-PMO) as a host material to anchor lanthanides for the purpose of developing a multifunctional chemical sensor. The host material was grafted with lanthanide chloride salts or complexes. The luminescence properties of the developed series of hybrid materials were studied in detail in the solid-state and after dispersing in water. The Eu3+ or Tb3+ singly incorporated materials were investigated for their use as ion sensors, showing ions selectivity towards Cu2+, Co2+ and Fe3+. Additionally, the Eu3+ or Tb3+ incorporated materials showed obvious luminescence quenching behavior towards acetone compared to other organic solvents, indicating excellent acetone sensing selectivity.
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An approach of implementing X-bar and R control charts as a statistical control tool to monitor the changes in the melting profile of fresh and stored flaxseed oils by differential scanning calorimetry (DSC) was used. Phase transition melting profiles were collected after 0, 2, 4, and 6 months of storing flaxseed oils, originating from five different cultivars. Four peaks at around -36, -30, -25, and -12 °C were identified using the deconvolution analysis procedure, which enabled the data to be collected at peak temperature (T), peak height (h), the peak area (A), and the percentages of the area (P A), as well as the ratio calculated from these parameters. Control charts obtained for the second peak of the melting profile showed a significant decrease of peak height (h2) from 0.50 to 0.39 W/g and the percentage of the area (P A2) from 50 to 38%, within the storage time (p ≤ 0.05); thus, they were considered to be indicators of oil deterioration. Strong negative correlations of the unstable parameters of DSC with chemical indicators of the oils' oxidative stability (PV, p-AV, TOTOX) were found. For DSC parameters, related to the first peak (h1, A1) and the third peak (h3, A3), changes were statistically not significant within storage (p > 0.05); thus, they can be used as markers of flaxseed oil authenticity. The study demonstrated that X-bar and R control charts could effectively monitor changes in the specific peaks and calculated ratios from the DSC melting profile of fresh and stored flaxseed oils, serving as reliable indicators of oil deterioration.
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In this study, we report hybrid crystalline lanthanide-containing 3D covalent organic framework (Ln@3D COF) materials that are suitable for temperature sensing applications. Different routes to obtain these hybrid materials were tested and compared for material quality and thermometric properties. In the first approach, a bipyridine-containing 3D COF (Bipy COF) was grafted with a range of visible emitting lanthanide (Eu3+, Tb3+, Dy3+, and Eu3+/Tb3+) ß-diketonate complexes. In the second approach, a novel nanocomposite material was prepared by embedding NaYF4:Er,Yb nanoparticles on the surface of a nonfunctionalized 3D COF (COF-300). To the best of our knowledge, the luminescent materials developed here are the first 3D COFs to be tested as ratiometric temperature sensors. In fact, for the Bipy COF, two different types of thermometers were tested (the Eu3+/Tb3+ system and a rare Dy3+ system), with both showing excellent temperature sensing properties. The reported NaYF4:Er,Yb/COF-300 nanocomposite material combines upconverting nanoparticles with 3D COFs, similar to previously reported metal organic framework (MOF) nanocomposite materials; however, this type of hybrid material has not yet been explored for COFs. As such, our findings open a new pathway toward potential multifunctional materials that can combine thermometry with other modalities, such as catalysis or drug delivery, in just one nanocomposite material.
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BACKGROUND: Therapies using electromagnetic field technology show evidence of enhanced bone regeneration at the fracture site, potentially preventing delayed or nonunions. METHODS: Combined electric and magnetic field (CEMF) treatment was evaluated in two standardized sheep tibia osteotomy models: a 3-mm non-critical size gap model and a 17-mm critical size defect model augmented with autologous bone grafts, both stabilized with locking compression plates. CEMF treatment was delivered across the fracture gap twice daily for 90 min, starting 4 days postoperatively (post-OP) until sacrifice (9 or 12 weeks post-OP, respectively). Control groups received no CEMF treatment. Bone healing was evaluated radiographically, morphometrically (micro-CT), biomechanically and histologically. RESULTS: In the 3-mm gap model, the CEMF group (n = 6) exhibited higher callus mineral density compared to the Control group (n = 6), two-fold higher biomechanical torsional rigidity and a histologically more advanced callus maturity (no statistically significant differences). In the 17-mm graft model, differences between the Control (n = 6) and CEMF group (n = 6) were more pronounced. The CEMF group showed a radiologically more advanced callus, a higher callus volume (p = 0.003) and a 2.6 × higher biomechanical torsional rigidity (p = 0.024), combined with a histologically more advanced callus maturity and healing. CONCLUSIONS: This study showed that CEMF therapy notably enhanced bone healing resulting in better new bone structure, callus morphology and superior biomechanical properties. This technology could transform a standard inert orthopedic implant into an active device stimulating bone tissue for accelerated healing and regeneration.
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Magnetoterapia , Fraturas da Tíbia , Ovinos , Animais , Consolidação da Fratura , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , Calo Ósseo/diagnóstico por imagem , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia , Osteotomia , Fenômenos BiomecânicosRESUMO
In the quest for essential energy solutions towards an ecological friendly future, the transformation of visible light/solar energy into mechanical motions in metal-free luminescent crystals offers a sustainable choice of smart materials for lightweight actuating, and all-organic electronic devices. Such green energy-triggered photodynamic motions with room temperature phosphorescence (RTP) emission in molecular crystals have not been reported yet. Here, we demonstrate three new stoichiometrically different Lewis acid-base molecular organoboron crystals (PS1, PS2, and PS3), which exhibit rapid photosalient effects (ballistic splitting, moving, and jumping) under both ultraviolet (UV) and visible light associated with quantitative single-crystal-to-single-crystal (SCSC) [2+2] cycloaddition of preorganized olefins. Furthermore, these systems respond to sunlight and mobile (white) flashlight with a complete SCSC transformation in a relatively slow fashion. Remarkably, all PS1, PS2, and PS3 crystals display visible light-promoted dynamic green RTP as their emission peaks promptly blue-shift, due to instantaneous photomechanical effects. Time-dependent structural mapping of intermediate photoproducts during fast SCSC [2+2] photoreaction, by X-ray photodiffraction, reveals a rationale for the origin of these photodynamic motions associated with rapid topochemical transformations. The reported light-driven behavior (mechanical motions, dynamic phosphorescence, and topochemical reactivity), is considered advantageous for the strategic design of stimuli-responsive multi-functional crystalline materials.
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Photoluminescent molecular crystals integrated with the ability to transform light energy into macroscopic mechanical motions are a promising choice of materials for both actuating and photonic devices. However, such dynamic photomechanical effects, based on molecular organoboron compounds as well as phosphorescent crystalline materials, are not yet known. Here we present an intriguing example of photomechanical molecular single crystals of a newly synthesized organoboron containing Lewis acid-base molecular adduct (BN1, substituted triphenylboroxine and 1,2-di(4-pyridyl)ethylene) having a capsule shape molecular geometry. The single crystals of BN1 under UV light exhibit controllable rapid bending-shape recovery, delamination, violent splitting-jumping, and expanding features. The detailed structural investigation by single-crystal X-ray diffraction and 1H NMR spectroscopy reveals that the photosalient behavior of the BN1 single crystals is driven by a crystal-to-crystal [2 + 2] cycloaddition reaction, supported by four donor-acceptor type BâN bonds. The instant photomechanical reaction in the BN1 crystals occurs under UV on account of sudden release of stress associated with the strained molecular geometry, significant solid-state molecular movements (supramolecular change), and cleavage of half intermolecular BâN linkages to result in a complete photodimerized single-crystalline product via the existence of two other intermediate photoproducts. In addition, the BN1 crystals display short-lived room temperature phosphorescence, and the photodynamic events are accompanied by the enhancement of their phosphorescence intensity to yield the photoproduct. Interestingly, the molecular crystals of the final photoproduct polymerize at ambient conditions when recrystallized from the solution forming a 2D supramolecular crystalline polymer stabilized by the retention of all BâN coordination modes.
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Reação de CicloadiçãoRESUMO
Employing luminescence thermometry in the biomedical field is undeniably appealing as many health conditions are accompanied by temperature changes. In this work, we show our ongoing efforts and results at designing novel vehicles for dual-mode thermometry and pH-dependent drug release based on hollow spheres. Hereby for that purpose, we exploit the hollow Y2O3 and Y2O2SO4 host materials. These two inorganic hollow phosphors were investigated and showed to have excellent upconversion Er3+-Yb3+ luminescence properties and could be effectively used as optical temperature sensors in the physiological temperature range when induced by near-infrared CW light (975 nm). Further, doxorubicin was exploited as a model anti-cancer drug to monitor the pH-dependent drug release of these materials showing that they can be used for simultaneous thermometry and drug delivery applications.
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Mechanically responsive organic luminescent crystals are one of the promising choices of materials for flexible photonic devices. However, the change in phosphorescence emission as a function of the flexibility of a crystal has never been reported. Our current findings demonstrate two-dimensional (2D) and one-dimensional (1D) macroscopic elastic deformability, under mechanical stress, in elastically flexible single crystals of dibenzothiophene, and its brominated derivative, respectively. Unlike the presence of dual fluorescence (FL) and room temperature phosphorescence (RTP) in dibenzothiophene single crystals, the derivative was found to show only RTP. Interestingly, upon elastic deformation, single crystals of the dual emissive dibenzothiophene show a noticeable blue shift (â¼20 nm) of RTP emission when compared to their pristine crystals (straight and naturally bent). However, their FL peaks remain nearly unchanged irrespective of the crystal deformation. A hierarchy of structure-elastic functionality to RTP modulation has been quantitatively mapped by rationalizing the role of chalcogen-involved weak interactions.
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This paper takes into consideration the performance of traditional bricks as part of a building exterior wall finish. Exterior wall materials change their properties when exposed to external environment. This process is extended over time and its intensity is closely related to microstructure, moisture and freeze-thaw cycles. Two methods of freeze-thaw durability tests were used in this study: standard and defined by the authors. The authors' method incorporated the actual conditions of masonry unit function in exterior wall finish, i.e., cyclical effects of precipitation water, changes in temperature and air humidity. The laboratory test study included 50 freeze-thaw cycles. Three characteristic ranges of pore dimensions were indicated in the analysis: below 0.1 µm, between 0.1 and 3.0 µm and above 3 µm. Based on the method of freeze-thaw durability testing, the areas of microstructure changes were determined. The obtained results were related to the absorption of ceramic building materials. The authors' method confirms the usage of traditional ceramic building materials designed for use in protected walls against water penetration in unprotected exterior wall finish. The critical water saturation method of masonry units (standard) based on extreme environmental conditions generates significant changes in porosity distribution that do not reflect real, i.e., moderate, conditions. This method is appropriate for masonry units operating in severe conditions, i.e., F2. The aim of this study is to suggest a methodology for durability tests of traditional ceramic masonry units to cyclic freezing and thawing, which are only exposed to F1 (moderate) conditions during operation. Changes in the microstructure of the ceramic building materials were used as the primary evaluation criterion. In order to determine the effect of cyclic temperature changes, the freeze-thaw durability test was performed according to generally accepted standard procedures and in-house methodology. The purpose of the study is to point out the individual approach for the analysis of the material-environment system. At the same time, it should inspire researchers to innovative methods which use external conditions in a laboratory environment.
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Recent advances reveal that upconversion (UC) luminescent materials are highly important not just from a scientific, but also from a future application standpoint. Although significant progress has been made in this field in recent decades, still their versatile applications are hindered by the low upconversion luminescence intensity and low tuneability, which has hampered further implementation in real life applications. We find it highly beneficial to compile a summary of recent relevant literature and propose ways to enhance upconversion efficiency in lanthanide nanomaterials. One very promising way to tackle this problem is through implementing transition metal ion co-dopants into the materials, which is the focus of this tutorial review. In this review, the recent studies related to the tailored design of UC materials with transition metal ion co-dopants have been summarized, and the desirable functionality of transition metal ions in the host matrixes has been discussed. Apart from improving the upconversion efficiency, the implementation of transition metal-co-dopants into lanthanide upconversion materials has recently sparked interest in applications such as in vivo imaging, drug delivery or nanothermometers.