From Dielectric to Electro-Responsive Thermoplastics: An Approach Based on Electro-Thermal Reorientation and Charged Gas Activation.

The transition from insulator to electro-responsive has been successfully achieved by earlier studies for some inorganic materials by applying external stimuli that modify their 3D and/or electronic structures. In the case of insulating polymers, this transition is frequently accomplished by mixing them with other electroactive materials, even though a few physical treatments that induce suitable chemical modifications have also been reported. In this work, a smart approach based on the application of an electro-thermal reorientation process followed by a charged gas activation treatment has been developed for transforming insulating 3D printed polymers into electro-responsive materials.

Green Synthesis of Urea from Carbon Dioxide and Ammonia Catalyzed by Ultraporous Permanently Polarized Hydroxyapatite.

The sustainable synthesis of urea from ammonia (NH) and carbon dioxide (CO) using ultraporous permanently polarized hydroxyapatite (upp-HAp) as catalyst has been explored as an advantageous CO-revalorization strategy. As the simultaneous activation of N and CO (single-step) demands an increase of the reaction conditions, we have re-visited the industrial two-step Bazarov reaction. upp-HAp has been designed as a stable multifunctional catalyst capable of promoting both CO and NH adsorption for their subsequent C-N bond formation.

Size-Dependent High-Pressure Behavior of Pure and Eu-Doped YO Nanoparticles: Insights from Experimental and Theoretical Investigations.

We report a joint high-pressure experimental and theoretical study of the structural, vibrational, and photoluminescent properties of pure and Eu-doped cubic YO nanoparticles with two very different average particle sizes. We compare the results of synchrotron X-ray diffraction, Raman scattering, and photoluminescence measurements in nanoparticles with ab initio density-functional simulations in bulk material with the aim to understand the influence of the average particle size on the properties of pure and doped YO nanoparticles under compression. We observe that the high-pressure phase behavior of YO nanoparticles depends on the average particle size, but in a different way to that previously reported.

Translating the COVID-19 epidemiological situation into policies and measures: the Belgian experience.

The COVID-19 pandemic led to sustained surveillance efforts, which made unprecedented volumes and types of data available. In Belgium, these data were used to conduct a targeted and regular assessment of the epidemiological situation. In addition, management tools were developed, incorporating key indicators and thresholds, to define risk levels and offer guidance to policy makers.

Establishing Quartz Crystal Microbalance with Dissipation (QCM-D) Coupled with Spectroscopic Ellipsometry (SE) as an Advantageous Technique for the Characterization of Ultra-Thin Film Hydrogels.

Despite the considerable significance of utilizing ultra-thin film (utf) hydrogels as multipurpose platforms for biomedical applications, there is still an important lack of adequate characterization techniques suitable for such materials. In this Perspective, the use of quartz crystal microbalance with dissipation (QCM-D) coupled with spectral ellipsometry (SE) is presented as a potential tool for the complete characterization of utf-hydrogels due to its nanometric sensitivity and high versatility. Herein, the fundaments for utf-hydrogel characterization are settled down as far as the QCM-D/SE response is explored under a wide range of different in operando wet working conditions measurements such as temperature or liquid media, among others.

Joint experimental and theoretical study of PbGaS under compression.

The effect of pressure on the structural, vibrational, and optical properties of lead thiogallate, PbGaS, crystallizing under room conditions in the orthorhombic EuGaS-type structure (space group ), is investigated. The results from X-ray diffraction, Raman scattering, and optical-absorption measurements at a high pressure beyond 20 GPa are reported and compared not only to calculations, but also to the related compounds α'-GaS, CdGaS, and HgGaS. Evidence of a partially reversible pressure-induced decomposition of PbGaS into a mixture of PbGaS and GaS above 15 GPa is reported.

Tailorable Nanoporous Hydroxyapatite Scaffolds for Electrothermal Catalysis.

Polarized hydroxyapatite (HAp) scaffolds with customized architecture at the nanoscale have been presented as a green alternative to conventional catalysts used for carbon and dinitrogen fixation. HAp printable inks with controlled nanoporosity and rheological properties have been successfully achieved by incorporating Pluronic hydrogel. Nanoporous scaffolds with good mechanical properties, as demonstrated by means of the nanoindentation technique, have been obtained by a sintering treatment and the posterior thermally induced polarization process.

Electroresponsive and pH-Sensitive Hydrogel as Carrier for Controlled Chloramphenicol Release.

Multiresponsive hydrogels, which are smart soft materials that respond to more than one external stimulus, have emerged as powerful tools for biomedical applications, such as drug delivery. Within this context and with the aim of eliminating the systematic administration of antibiotics, special attention is being paid to the development of systems for controlled delivery of antibiotic for topical treatment of bacterial infections. In this work, an electro-chemo responsive hydrogel able to release chloramphenicol (CAM), a broad spectrum antibiotic also used for anticancer therapy, is proposed.

Pyroreflectometry as a technique for the accurate measurement of very high temperatures in molten materials.

Experimental research into severe nuclear accidents often requires the accurate measurement of high temperatures of molten materials. Measurements of very high temperatures (1500-2500 °C) in liquid materials using standard pyrometry can entail uncertainties in the order of 5%-10%. Pyroreflectometry is a powerful technique with the potential to significantly reduce these uncertainties.

Permanently polarized hydroxyapatite, an outstanding catalytic material for carbon and nitrogen fixation.

Hydroxyapatite (HAp) is a well-known ceramic material widely used in the biomedical field. This review summarizes the very recent developments on permanently polarized HAp (pp-HAp), a HAp variety with tuned electrical properties that confer remarkable catalytic activity. pp-HAp is obtained by applying a thermal stimulation polarization process (TSP), which consists on a DC electric voltage of 500 V at 1000 °C, to previously sintered HAp.

Unveiling the role of the lone electron pair in sesquioxides at high pressure: compressibility of β-SbO.

The structural, vibrational and electronic properties of the compressed β-Sb2O3 polymorph, a.k.a.

Permanently polarized hydroxyapatite for selective electrothermal catalytic conversion of carbon dioxide into ethanol.

Conversion of CO into valuable chemicals is not only a very challenging topic but also a socially demanding issue. In this work, permanently polarized hydroxyapatite obtained using a thermal stimulated polarization process is proposed as a highly selective catalyst for green production of ethanol starting from CO and CH.

PrVO under High Pressure: Effects on Structural, Optical, and Electrical Properties.

In the pursuit of a systematic characterization of rare-earth vanadates under compression, in this work we present a multifaceted study of the phase behavior of zircon-type orthovanadate PrVO under high-pressure conditions, up to 24 GPa. We have found that PrVO undergoes a zircon to monazite transition at around 6 GPa, confirming previous results found by Raman experiments. A second transition takes place above 14 GPa, to a BaWO-II type structure.

High-pressure Raman investigation of high index facets bounded-FeOpseudocubic crystals.

High index facet bounded α-FeOpseudocubic crystals has gained the attention of the scientific community due to its promising electrochemical sensing response towards aqueous ammonia. The structural stability of α-FeOpseudocubic crystals is investigated through high-pressure Raman spectroscopy up to 22.2 GPa, and those results are compared with ourtheoretical calculations.

Mapping IPF helps identify geographic regions at higher risk for disease development and potential triggers.

Background And Objective: The relationship between IPF development and environmental factors has not been completely elucidated. Analysing geographic regions of idiopathic pulmonary fibrosis (IPF) cases could help identify those areas with higher aggregation and investigate potential triggers. We hypothesize that cross-analysing location of IPF cases and areas of consistently high air pollution concentration could lead to recognition of environmental risk factors for IPF development.

Characterization and Decomposition of the Natural van der Waals SnSbTe under Compression.

High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of the topological electron density and electronic localization function, evidence the presence of an isostructural phase transition around 2 GPa, a Fermi resonance around 3.5 GPa, and a pressure-induced decomposition of SnSbTe into the high-pressure phases of its parent binary compounds (α-SbTe and SnTe) above 7 GPa. The internal polyhedral compressibility, the behavior of the Raman-active modes, the electrical behavior, and the nature of its different bonds under compression have been discussed and compared with their parent binary compounds and with related ternary materials.

Structural and Lattice-Dynamical Properties of TbO under Compression: A Comparative Study with Rare Earth and Related Sesquioxides.

We report a joint experimental and theoretical investigation of the high pressure structural and vibrational properties of terbium sesquioxide (TbO). Powder X-ray diffraction and Raman scattering measurements show that cubic 3̅ (C-type) TbO undergoes two phase transitions up to 25 GPa. We observe a first irreversible reconstructive transition to the monoclinic 2/ (B-type) phase at ∼7 GPa and a subsequent reversible displacive transition from the monoclinic to the trigonal 3̅1 (A-type) phase at ∼1 GPa.

High-pressure characterization of multifunctional CrVO.

The structural stability and physical properties of CrVOunder compression were studied by x-ray diffraction, Raman spectroscopy, optical absorption, resistivity measurements, andcalculations up to 10 GPa. High-pressure x-ray diffraction and Raman measurements show that CrVOundergoes a phase transition from the ambient pressure orthorhombic CrVO-type structure (Cmcm space group, phase III) to the high-pressure monoclinic CrVO-V phase, which is proposed to be isomorphic to the wolframite structure. Such a phase transition (CrVO-type → wolframite), driven by pressure, also was previously observed in indium vanadate.

Orpiment under compression: metavalent bonding at high pressure.

We report a joint experimental and theoretical study of the structural, vibrational, and electronic properties of layered monoclinic arsenic sulfide crystals (α-AsS), aka mineral orpiment, under compression. X-ray diffraction and Raman scattering measurements performed on orpiment samples at high pressure and combined with ab initio calculations have allowed us to determine the equation of state and the tentative assignment of the symmetry of many Raman-active modes of orpiment. From our results, we conclude that no first-order phase transition occurs up to 25 GPa at room temperature; however, compression leads to an isostructural phase transition above 20 GPa.

Electrically Polarized Hydroxyapatite: Influence of the Polarization Process on the Microstructure and Properties.

Semipermanently polarized hydroxyapatite, named SP/HAp(w), is obtained by applying a constant dc electric field of 1-10 kV/cm at 300-850 °C to the samples previously sintered in water vapor, while permanently polarized hydroxyapatite, PP/HAp(a), is produced by applying a dc electric field of 3 kV/cm at 1000 °C to the samples sintered in air. SP/HAp(w) has been used for biomedical applications, while PP/HAp(a) has been proved to be a valuable catalyst for N and CO fixation. In this work, structural differences between SP/HAp(w) and PP/HAp(a) have been ascertained using Raman microscopy, wide-angle X-ray diffraction, scanning electronic microscopy, high-resolution transmission electron microscopy, and grazing incidence X-ray diffraction.