Spectroscopic and Structural Properties of β-Tricalcium Phosphates Ca9RE(PO4)7 (RE = Nd, Gd, Dy)

Rare-earth-based Ca9RE(PO4)7 (RE = Nd, Gd, Dy) materials were synthesized by solid-state reaction at T = 1200 °C. The obtained tricalcium phosphate (TCP) materials are efficient light emitters due to the presence of RE3+ ions, although these ions are present at high concentrations. Moreover, in these host structures, these ions can be used as optical probes to study their local environments. Thus, photoluminescence (PL) emission spectra of the powder samples clearly indicated, for Dy3+ and Gd3+ ions, the presence of the RE3+ ion in low-symmetry sites with some local structural disorder, and the spectra show the presence of vibrational features (in the case of Gd3+). For the Nd3+ phase, emission bands are present around 900, 1050, and 1330 nm, originating from the 4F3/2 level. In general, these RE-TCP samples are interesting luminescent materials in the visible (Dy), UV (Gd), and NIR (Nd) regions, due to weak concentration quenching even for high concentrations of the emitting ion

Diammonium tris­[hexa­aqua­magnesium(II)] tetra­kis­[hydrogenphosphate(III)], (NH4)2[Mg(H2O)6]3(HPO3)4

The framework of the title compound is made up of discrete Mg(H2O)6 octa¬hedra, and HPO3 and NH4 tetra¬hedra, which are organized in planes parallel to (010). Strong hydrogen bonding between the building units stabilizes the structure. The hydrogenphosphate(III) tetra¬hedra, the ammonium tetra¬hedron and one of the two Mg atoms lie on positions with m symmetry, whereas the second Mg atom is located on a position with 2/m symmetry

Vibrational level population of H2_2 and H2+_2^+ in the early Universe

We formulate a vibrationally resolved kinetics for molecular hydrogen and its cation in the primordial Universe chemistry. Formation, destruction and relaxation processes for each vibrational level are studied and included as chemical pathways of the present model. The fractional abundance of each vibrational level as a function of the redshift is given: a strong deviation from the Boltzmann distribution is found at low $z$. A discussion of the results is provided, also evaluating the effects of relaxation processes on the level populations. Analytical fits for some LTE rate coefficients are given in the Appendix.Comment: 12 pages, 14 figures, 3 tables; published on ApJS 2011, 193,

Electrochemical and Structural Characterization of Lanthanum-Doped Hydroxyapatite: A Promising Material for Sensing Applications

In the quest to find powerful modifiers of screen-printed electrodes for sensing applications, a set of rare earth-doped Ca10-xREx(PO4)(6)(OH)(2) (RE = La, Nd, Sm, Eu, Dy, and Tm and x = 0.01, 0.02, 0.10, and 0.20) hydroxyapatite (HAp) samples were subjected to an in-depth electrochemical characterization using electrochemical impedance spectroscopy and cyclic and square wave voltammetry. Among all of these, the inorganic phosphates doped with lanthanum proved to be the most reliable, revealing robust analytical performances in terms of sensitivity, repeatability, reproducibility, and reusability, hence paving the way for their exploitation in sensing applications. Structural data on La-doped HAp samples were also provided by using different techniques, including optical microscopy, X-ray diffraction, Rietveld refinement from X-ray data, Fourier transform infrared, and Raman vibrational spectroscopies, to complement the electrochemical characterization

Functional nano-hydroxyapatite for applications in conservation of stony monuments of cultural heritage

Stone is one of the most durable construction materials used in historic buildings all over the world. However, over time, the stone can be subject to various degradation processes leading to physical and chemical modifications. Although these effects may be limited to the surface and negligible to the structural stability of the affected buildings, they can represent a major problem in decorative elements of artistic value, where any detail should be preserved [1]. The challenge for conservators and material scientists involved in stone conservation has always been to find a way to stop or delay the effects of these degradation processes. The basic principle of the patrimony is that the cultural heritage is an incalculable and integral legacy to our future: observing and knowing the past, will help next generations to better challenge the future. Thus, conservation of stone heritage is always a delicate and complex task, due to the multiple variables that have to be taken into account to identify the problems, and to define the necessary conservation actions and to select materials and best procedures to be used. The variety of factors to be analyzed includes the intrinsic stone properties (from geological features up to mechanical behavior), the state of conservation, the degradation mechanisms and the environmental factors. One of the most promising technology employed for lowering the previously described degradation processes, is that of nanomaterials, nowadays largely applied in the maintenance of the world cultural heritage, with the aim of improving the consolidation and protection treatments of damaged stone materials they are made of [2]. Such nanomaterials display important advantages that could solve many problems found in the traditional interventions, that often showed the serious bias of the lack the vital compatibility with the original substrate and a durable performance: application of nanotechnology in the cultural heritage conservation is characterized by the possibility to design consolidant products strongly compatible with the original stone substrate. Moreover, when particles have dimensions of about 100 nanometers, the material properties change significantly from those at larger scales. The nanoparticles must show: stability and sustained photoactivity; biological and chemical inactivity nontoxicity, as well as antimicrobial properties for lowering ecotoxicological impact on animals and plants [3]; low cost suitability towards visible or near UV light; high conversion efficiency and high quantum yield. In addition, these treatments can also have water repellent properties which favor this self-cleaning action and prevent the generation of damage caused by water. The most commonly used inorganic consolidant agents are the products based on Ca(OH)2 calcium hydroxide nanoparticles [4], due to their compatibility with a large part of the built and sculptural heritage. As well as other hydroxides (Mg(OH)2, Sr(OH)2), metal oxides (TiO2, ZnO), and metal nanoparticles (Au, Ag, Pt)) have been reported in the literature, focusing on their potential as consolidants on different artifacts of cultural heritage [2, 5]. But one of the most challenging nanomaterial is Ca10(PO4)6(OH)2 hydroxyapatite (HAP), already applied in a large variety of technological and biomedical applications, mainly due to its close relationship with mineral component of hard human tissues [6-7], and in cultural heritage conservation used for carbonate stone consolidation [2]. HAP can be applied for the consolidation of limestones, marbles and sandstones with different carbonate contents. This product is not introduced directly into stone material, but it comes from the reaction between phosphate ions from an aqueous solution of diammonium hydrogen phosphate applied to the stone and calcium ions coming from substrate. Among its advantages, HAP has a similar crystal structure and close lattice parameters of CaCO3 calcite, the main constituents of marbles and limestone. Thanks to its low viscous nature, this aqueous consolidant product is able to penetrate deeply into the stone, generating a significant improvement in mechanical properties of the same stone. The HAP has been tested as a protective treatment for marble against acid rain corrosion [8]. The study of compatibility and adaptability requires that the physical and chemical properties of both consolidator products and stone substrate are well known. Such a knowledge plays a very important role for the good outcome of the present project. Materials of interest, synthesized in our labs has been analysed by using: 1) X-ray diffraction (XRD), effective on crystalline materials and able to carry out information on chemical composition, size, shape and atomic structure, 2) small- and/or wide-angle scattering (SAXS/WAXS), powerful tool to investigate the domain of phosphate particles as a function of their optical properties; in the case of SAXS the technique can be applied to HAp nanoparticles characterization; 3) Fourier-Transform Infrared (FTIR) spectroscopy, reliable techniques for investigating hydroxyl anions and variations within anionic and cationic groups in the obtained materials; 4) scanning electron microscopy for checking morphologies of nanonparticles; 5) biological evaluation of the antimicrobial properties of obtained HAp materials, through direct contact and disc diffusion methods versus most common gram + and gram - bacteria present in human or animal biosystems 6) Laser Induced Breakdown Spectroscopy (LIBS), a non-destructive technique able to get quali-quantitative informations on museal artifacts. 1 - Pesce C., Moretto L.M., Orsega E.F., Pesce G.L., Corradi M., Weber J. Effectiveness and Compatibility of a Novel Sustainable Method for Stone Consolidation Based on Di-Ammonium Phosphate and Calcium-Based Nanomaterials. Materials 12 (2019) 3025. 2 - David, M.E., Ion, R.-M., Grigorescu, R.M., Iancu, L., Andrei, E.R. Nanomaterials Used in Conservation and Restoration of Cultural Heritage: An Up-to-Date Overview. Materials 13 (2020) 2064. 3 - Reyes-Estebanez, M., Ortega-Morales, B.O., Chan-Bacab, M., Granados-Echegoyen, C., Camacho-Chab, J.C., Pereanez-Sacarias J.E., Gaylarde C. Antimicrobial engineered nanoparticles in the built cultural heritage context and their ecotoxicological impact on animals and plants: a brief review. Heritage Science 6 (2018) 52. 4 - El Bakkari M, Bindiganavile V, Boluk Y. Facile Synthesis of Calcium Hydroxide Nanoparticles onto TEMPO-Oxidized Cellulose Nanofibers for Heritage Conservation. ACS Omega 4 (2019) 20606-20611. 5 - Dida B., Siliqi D., Baldassarre, F., Karaj D., Hasimi A., Kasemi V., Nika V., Vozga I. "Nanomaterialet per Konservimin e Trashegimise Kulturore", SHLBSH, Tirana (2020), ISBN 978-99943-2-468-2 6 - Rakovan J.R., Pasteris J.D. A technological gem: Materials, Medical, and Environmental Mineralogy of Apatite. Elements 11 (2015) 195-200. 7 - Baldassarre F., Altomare A., Corriero N., Mesto E., Lacalamita M., Bruno G., Sacchetti A., Dida B., Karaj D., Della Ventura G.D., Capitelli, F., Siliqi, D. Crystal Chemistry and Luminescence Properties of Eu-Doped Polycrystalline Hydroxyapatite Synthesized by Chemical Precipitation at Room Temperature. Crystals 10 (202) 250. 8 - Graziani G., Sassoni E., Franzoni E., Scherer G.W. Hydroxyapatite Coatings for Marble Protection: Optimization of Calcite Covering and Acid Resistance. Applied Surface Science 368 (2016) 241-257

Lesson by SARS-CoV-2 disease (COVID-19): whole-body CT angiography detection of "relevant" and "other/incidental" systemic vascular findings

Objectives: Increasing evidence suggests that SARS-CoV-2 infection may lead to severe and multi-site vascular involvement. Our study aimed at assessing the frequency of vascular and extravascular events' distribution in a retrospective cohort of 42 COVID-19 patients. Methods: Patients were evaluated by whole-body CT angiography between March 16 and April 30, 2020. Twenty-three out of the 42 patients evaluated were admitted to the intensive care unit (ICU). Vascular and extravascular findings were categorized into "relevant" or "other/incidental," first referring to the need for immediate patient care and management. Student T-test, Mann-Whitney U test, or Fisher exact test was used to compare study groups, where appropriate. Results: Relevant vascular events were recorded in 71.4% of cases (n = 30). Pulmonary embolism was the most frequent in both ICU and non-ICU cases (56.5% vs. 10.5%, p = 0.002). Ischemic infarctions at several sites such as the gut, spleen, liver, brain, and kidney were detected (n = 20), with multi-site involvement in some cases. Systemic venous thrombosis occurred in 30.9% of cases compared to 7.1% of systemic arterial events, the first being significantly higher in ICU patients (p = 0.002). Among incidental findings, small-sized splanchnic arterial aneurysms were reported in 21.4% of the study population, with no significant differences in ICU and non-ICU patients. Conclusions: Vascular involvement is not negligible in COVID-19 and should be carefully investigated as it may significantly affect disease behavior and prognosis. Key points: • Relevant vascular events were recorded in 71.4% of the study population, with pulmonary embolism being the most frequent event in ICU and non-ICU cases. • Apart from the lung, other organs such as the gut, spleen, liver, brain, and kidneys were involved with episodes of ischemic infarction. Systemic venous and arterial thrombosis occurred in 30.9% and 7.1% of cases, respectively, with venous events being significantly higher in ICU patients (p = 0.002). • Among incidental findings, small-sized splanchnic arterial aneurysms were reported in 21.4% of the whole population

Impiego degli Inibitori della Pompa protonica (IPP) in Piemonte: indagine sulle abitudini prescrittive dei Medici di Medicina Generale

Proton Pump Inhibitors (PPIs) (Omeprazole, Lansoprazole, Pantoprazole, Rabeprazole and Esomeprazole), one of the most commonly prescribed classes of medications in the primary care setting, are considered a major advance in the treatment of acid-peptic diseases. In Italy PPIs are reimbursed by National Health Service on the basis of CUF (Commissione Unica del Farmaco) 1 and 48 Notes. In 2002 and 2003 a significant increase in PPIs consumption and expenditure have been documented, showing differences between regions. The aim of this study is to investigate and monitor, at regional level, type and entity of PPIs use through a drug utilization study, evaluating prescribing behaviour and compliance of PPIs treatments with CUF Notes indications. The study has been carried out on a sample of 436 General Practitioners belonging to 22 Piemonte's ASL (Aziende Sanitarie Locali). The data analysis shows that acid-related pathologies are significantly more common in patients with at least 50 years of age and the most frequent condition is represented by gastroesophageal reflux disease. Despite the general conditions of PPIs use by General Practitioners in terms of duration and dosage of therapy result in most cases (from 49% to 80% for duration and from 54% to 97% for dosage) compliant with what proposed by CUF Notes, in some cases the same CUF Notes indications seem to be not observed. Consequently the Piemonte Region has decided to plan a guideline on PPIs rational use. Such guideline, expected to be introduced in the regional area, may also be considered as an instrument able to lead to a more appropriate expenditure for this drug class. Moreover, in order to control PPIs expenditure, pharmacoeconomic methodologies can be applied allowing to identify the most cost - effective active substance and therapeutic scheme, overcoming CUF Notes which consider all PPIs use under the same reimbursement conditions

Structural Motifs in Enantiopure Halogenated Aryl Benzyl Sulfoxides: Effect of Fluorine Substitution

A series of enantiopure crystalline aryl benzyl sulfoxides, bearing different substituents on both the aryl groups, were synthesized by an enantioselective oxidation of the corresponding sulfides. Structural investigations, achieved by means of single-crystal X-ray diffraction, allowed us to recognize the main assembling interactions. The same procedure was repeated for some corresponding fluorinated aryl benzyl sulfoxides. The synthesis of the enantiomers of a new fluorinated compound, which shows unusual structural patterns, prompted us to compare the structural motifs of the two families of sulfoxides (fluorinated and unfluorinated) and to investigate the changes due to the fluorine substitution. Some short contacts involving the fluorine atom were discussed in more details, taking into account the recent interest in these sometimes controversial interactions

Classical collision integrals from computed interactions of alkali ions with rare gases

Transport-controlling collision integrals have been computed. within a classical framework, for alkali ions interacting with rare gases and for a fairly large range of temperatures.Ab initio calculated potential curves for these systems have been employed for the first time to obtain cross sections, after having fitted several chosen functional forms to their numerical values.The different ranges of validity for each of the forms, that are among those most generally used in the literature within empirical models, are discussed at length and a set of parameters obtained to yield a continuous, smoothly connected, analytical expression for each curve.Some of the computed [math] values are then compared with the corresponding values that are obtained by using « experimental » potentials