140 research outputs found

    New multifunctional sulfonato-containing metal phosphonates proton conductors

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    Anchoring of acidic functional groups to organic linkers acting as ligands in metal phosphonates has been demonstrate to be a valid strategy to develop new proton conductor materials, which exhibit tunable properties and are potentially applicable to proton exchange membranes, such as those used in PEMFCs [1,2]. In this work, the structural and proton conductivity properties of several families of divalent and trivalent metal amino-sulfophosphonates are presented. The chosen ligand, (H2O3PCH2)2-N-(CH2)2-SO3H, was reacted with the appropriate metal salt using highthrough-put screening and/or microwave-assisted synthesis. Different crystal structures haven been solved displaying a variety of metal ligand coordination modes, in whose frameworks acidic groups contribute to create strong H-bond networks; together with lattice and bound water molecules. Proton conductivity values oscillate between 10-4 and 10-2 S.cm-1, at 80 ÂșC and 95 % relative humidity, most of them showing activation energies characteristic of a Grotthuss-type proton transport mechanism.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech. MINECO: MAT2016-77648-R Junta de AndalucĂ­a: P-12-FQM-1656 y FQM-11

    Proton conductivity and luminiscence properties of lanthanide aminotriphosphonates

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    Metal phosphonates are multifunctional solids with tunable properties, such as internal H-bond networks, and high chemical and thermal stability [1]. In the present work, we describe the synthesis, structural characterization, luminescent properties and proton conduction performance of a new family of isostructural cationic compounds with general formula [Ln(H4NMP)(H2O)2]Cl·2H2O [Ln = La3+, Pr3+, Sm3+, Gd3+, Tb3+, Dy3+, Ho3+, H6NMP = nitrilotris(methylphosphonic acid)]. These solids are formed by positively charge layers, which consist of isolated LnO8 polyhedra and bridge chelating NMP2- ligands, held apart by chloride ions and water molecules. This arrangement result in extended interlayer hydrogen networks with possible proton transfer pathways. The proton conductivity of Gd3+ sample, selected as prototype of the series, was measured. In the range between range 25Âș and 80 ÂșC, the conductivity increase with the temperature up to a maximum value of 3.10-4 S·cm-1, at relative humidity of 95 %. The activation energy obtained from the Arrhenius plot (Figure 1) is in the range corresponding to a Grotthuss transfer mechanism.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech. FQM-1656; MAT2013-41836-R

    Luminescent and Proton Conducting Lanthanide Coordination Networks Based On a Zwitterionic Tripodal Triphosphonate

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    The synthesis, structural characterization, luminescence properties, and proton conduction performance of a new family of isostructural cationic 2D layered compounds are reported. These have the general formula [Ln(H4NMP)- (H2O)2]Cl·2H2O [Ln = La3+, Pr3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, H6NMP = nitrilotris(methylphosphonic acid)], and contain Cl− as the counterion. In the case of Ce3+, a 1D derivative, [Ce2(H3NMP)2(H2O)4]·4.5H2O, isostructural with the known lanthanum compound has been isolated by simply crystallization at room temperature. The octa-coordinated environment of Ln3+ in 2D compounds is composed by six oxygen atoms from three different ligands and two oxygens from each bound water. Two of the three phosphonate groups act as both chelating and bridging linkers, while the third phosphonate group acts solely as a bridging moiety. The materials are stable at low relative humidity at less at 170 °C. However, at high relative humidity transform to other chloride-free phases, including the 1D structure. The proton conductivity of the 1D materials varies in a wide range, the highest values corresponding to the La derivative (σ ≈ 2 × 10−3 S·cm−1 at RH 95% and 80 °C). A lower proton conductivity, 3 × 10−4 S·cm−1, was measured for [Gd(H4NMP)(H2O)2]Cl·2H2O at 80 °C, which remains stable under the work conditions used. Absorption and luminescence spectra were recorded for selected [Ln(H4NMP)(H2O)2]Cl·2H2O compounds. In all of them, the observed transitions are attributed solely to f−f transitions of the lanthanide ions present, as the H4NMP2− organic group has no measurable absorption or luminescence properties.Proyecto nacional MAT2013-41836-R (MINECO) y Proyecto de la Junta de Andalucía P12-FQM-165

    Adherence to chronic medication in older populations: application of a common protocol among three European cohorts

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    Purpose: The purpose of this study was to evaluate and compare medication adherence to chronic therapies in older populations across different regions in Europe. Methods: This explorative study applied a harmonized method of data extraction and analysis from pharmacy claims databases of three European countries to compare medication adherence at a cross-country level. Data were obtained for the period between January 1, 2010, and December 31, 2011. Patients (aged >= 65 years) who newly initiated to oral antidiabetics, antihyperlipidemics, or antiosteoporotics were identified and followed for over a 12-month period. Main outcome measures were medication adherence (medication possession ratio, [MPR]; implementation) and persistence on index treatment. All country-specific data sets were prepared by employing a common data input model. Outcome measures were calculated for each country and pooled using random effect models. Results: In total, 39, 186 new users were analyzed. In pooled data from the three countries, suboptimal implementation (MPR <80%) was 52.45% (95% CI: 33.43-70.79) for antihyperlipidemics, 61.35% (95% CI: 52.83-69.22) for antiosteoporotics, and 30.33% (95% CI: 25.53-35.60) for oral antidiabetics. Similarly, rates of non-persistence (discontinuation) were 55.63% (95% CI: 35.24-74.29) for antihyperlipidemics, 60.24% (95% CI: 45.35-73.46) for antiosteoporotics, and 46.80% (95% CI: 36.40-57.4) for oral antidiabetics. Conclusion: Medication adherence was suboptimal with >50% of older people non-adherent to antihyperlipidemics and antiosteoporotics in the three European cohorts. However, the degree of variability in adherence rates among the three countries was high. A harmonized method of data extraction and analysis across health-related database in Europe is useful to compare medication-taking behavior at a cross-country level

    From light to heavy alkali metal tetraphosphonates (M = Li, Na, K, Rb, Cs): cation size-induced structural diversity and waterfacilitated proton conductivity

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    A family of alkali metal-based frameworks containing the tetraphosphonate ligand hexamethylenediamine- N,N,Nâ€Č,Nâ€Č-tetrakisÄČmethylenephosphonic acid), HDTMP, is reported. A cation size-induced structural diversity, from monodimensional solids (Li+ and Na+) through layered (K+) to pillared-layered (Rb+ and Cs+) structures, was found. The proton conductivity properties of the Li compounds (hydrated and dehydrated) are reported and the influence of dehydration/rehydration processes in enhancing proton transfer processes is highlighted. Reversible changes in the dimensionality occurred upon full dehydration/rehydration with minor rearrangements in the framework, implying variations in the Li+–ligand connectivity but preserving the tetracoordination of the metal ion. The reversibly dehydrated–rehydrated sample displayed the highest proton conductivity (5 × 10−3 S cm−1 at 80 °C and 95% RH), a behavior attributed to reversible formation/ reformation of P–OÄČH)–Li bonds that, in turn, provoked changes in the acidity of acid groups and water mobility in the temperature range of impedance measurements.Proyecto MAT2016-77648-R del ministerio y proyecto P12-FQM-1656 de la Junta de AndalucĂ­a Ministerio de EconomĂ­a y Competitividad por el contrato Ramon y Cajal (RyC2015-17870)

    Phase Transformation Dynamics in Sulfate-Loaded Lanthanide Triphosphonates. Proton Conductivity and Application as Fillers in PEMFCs

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    Phase transformation dynamics and proton conduction properties are reported for cationic layer-featured coordination polymers derived from the combination of lanthanide ions (Ln3+) with nitrilo-tris(methylenephosphonic acid) (H6NMP) in the presence of sulfate ions. Two families of materials are isolated and structurally characterized, i.e., [Ln2(H4NMP)2(H2O)4](HSO4)2·nH2O (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Er, Yb; n = 4−5, Series I) and [Ln(H5NMP)]SO4· 2H2O (Ln = Pr, Nd, Eu, Gd, Tb; Series II). Eu/Tb bimetallic solid solutions are also prepared for photoluminescence studies. Members of families I and II display high proton conductivity (10−3 and 10−2 S·cm−1 at 80 °C and 95% relative humidity) and are studied as fillers for Nafion-based composite membranes in PEMFCs, under operating conditions. Composite membranes exhibit higher power and current densities than the pristine Nafion membrane working in the range of 70−90 °C and 100% relative humidity and with similar proton conductivity.Proyectos de Ministero de Ciencia e InnovaciĂłn MAT2016-77648-R (MICINN/FEDER); PID2019-110249RB-I00 (MICINN/FEDER) y la Junta de Andalucía (FQM113). Funding for open access change: Universidad de MĂĄlaga/ CBU

    Coping with rheumatic stressors (CORS) questionnaire: Spanish translation and cross-cultural adaptation

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    Background: Rheumatic and Musculoskeletal Diseases (RMDs) substantially impact the lives of patients, with complex associations between disease severity and self-perceived health status. In this regard, the Coping with Rheumatic Stressors (CORS) questionnaire was developed to measure how patients with RMDs cope with stressors such as pain, limitations or dependency. The CORS is not currently available in Spanish, and therefore the adaptation of this instrument is needed.Objective: First, to cross-culturally adapt the CORS into Spanish for Spain. Secondly, to test the conceptual equivalence of the translated version in patients with axial spondyloarthritis (axSpA). Methods: A translation of the CORS into Spanish was performed adhering to the forward-backward procedure described by Beaton. Two translators produced independent forward translations of the item content, response options, and instructions of the CORS into Spanish. Both versions were harmonized in a consensual version. Another translator back-translated the synthesized version into Dutch. A scientific committee including all the translators, one methodologist and a rheumatologist, held a meeting and reached consensus on discrepancies to develop a final draft version of the Spanish CORS. Then, a field test with cognitive debriefing was conducted, involving a sample of 10 patients with axSpA. Results: The translation process of the CORS was completed after the discussion of some discrepancies throughout the process. The first translation was done without major complications. Back-translation presented some discrepancies. These led to minor modifications in the wording in one response option and 15 questionnaire items. The scientific committee agreed upon a final version of the questionnaire. Cognitive debriefing, led to minor modifications; for example, three respondents indicated that one of the statements in the instructions was syntactically complex ("indique cuan a menudo usted ha llevado a cabo dicho comportamiento") which led to its adjustment. The process indicated that the final CORS Spanish questionnaire was clear and understandable to all patients.Conclusions: The Spanish version of the CORS showed good cross-cultural validity and good face validity according to the field test. Before the Spanish CORS is implemented, further validation is in progress to test the psychometric properties of the instrument in patients with axSpA.Pathophysiology and treatment of rheumatic disease
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