Influence of anionic vacancies on the conductivity of La 9.33Si6-xAlxO26-x/2 oxide conductors with an oxyapatite structure

Al-doped oxyapatite-type lanthanum silicates La9.33Si 6-xAlxO26-x/2□x/2 (x = 0, 0.4, 0.8 and 1) powders have been prepared by the solid state reaction at high temperature in order to determine the influence of anionic vacancies on the electrical properties of the material. The crystal structure and properties of La9.33Si6-xAlxO 26-x/2□x/2 powders have been studied by X-ray diffraction (XRD) patterns, magic-angle spinning nuclear magnetic resonance (MAS-NMR) technique and complex impedance analysis. All the compounds of La 9.33Si6-xAlxO 26-x/2□x/2 oxyapatites doped with Al3+ consist of a hexagonal structure with a P63/m space group. Lanthanum silicates doped with trivalent Al3+ have a higher conductivity than those without trivalent Al3+ at the Si4+ site. The extra oxygen O(4) atoms in site 2a (0, 0, 0.25) occupy channels running through the structure that are responsible for the high oxygen ion conduction. However, Al substitution seems to produce oxygen vacancies and create another pathway for oxide ions. The expansion of the channels (La(1)-O(4) distance) leads to an increase in the conductivity. For the best sample (x = 1), the conductivity observed was 5 × 10-3 S cm-1 at 750 °C. © 2014 Published by Elsevier B.V.This work was supported by Spanish Agency of International Cooperation (AECI-B/026856/09).Peer Reviewe

Structural aspects that enhance oxygen mobility in La9-2 x/3Mn0.5 REx□0.5-x/3(SiO4)6O 2 with RE = Ca, Sr and Ba

Oxyapatite-type silicates, La9-2x/3Mn 0.5 REx□0.5-x /3(SiO4)6O2 (x = 0.5; RE = Ca, Sr and Ba), were prepared by a high temperature solid-state reaction. Structure and unit-cell parameters were deduced from the analysis of X-ray powder diffraction data. Le Bail refinement of the X-ray powder diffraction data showed that the compounds have a hexagonal cell (P 63/m space group). The electrical properties of the materials were studied using the ac impedance spectroscopy technique. The extra oxygen O(4) atoms in site 2a (0, 0, 0.25) occupy channels running through the structure that are responsible for the high oxygen ion conduction. The presence of cation vacancies should enhance oxygen hopping along the c-axis; however, the analysis of the frequency dependence of ac conductivity suggests that oxygen motions are produced along three axes. The n-factor value of the dimensionality of the oxide ions increases with the conductivity when the size of RE cation decreases. © 2014 Elsevier B.V. All rights reserved.Peer Reviewe

A multidimensional approach to older patients during COVID-19 pandemic: a position paper of the Special Interest Group on Comprehensive Geriatric Assessment of the European Geriatric Medicine Society (EuGMS)

Purpose: The COVID-19 pandemic has been a dramatic trigger that has challenged the intrinsic capacity of older adults and of society. Due to the consequences for the older population worldwide, the Special Interest Group on Comprehensive Geriatric Assessment (CGA) of the European Geriatric Medicine Society (EuGMS) took the initiative of collecting evidence on the usefulness of the CGA-based multidimensional approach to older people during the COVID-19 pandemic. Methods: A narrative review of the most relevant articles published between January 2020 and November 2022 that focused on the multidimensional assessment of older adults during the COVID-19 pandemic. Results: Current evidence supports the critical role of the multidimensional approach to identify older adults hospitalized with COVID-19 at higher risk of longer hospitalization, functional decline, and short-term mortality. This approach appears to also be pivotal for the adequate stratification and management of the post-COVID condition as well as for the adoption of preventive measures (e.g., vaccinations, healthy lifestyle) among non-infected individuals. Conclusion: Collecting information on multiple health domains (e.g., functional, cognitive, nutritional, social status, mobility, comorbidities, and polypharmacy) provides a better understanding of the intrinsic capacities and resilience of older adults affected by SARS-CoV-2 infection. The EuGMS SIG on CGA endorses the adoption of the multidimensional approach to guide the clinical management of older adults during the COVID-19 pandemic

Comprehensive geriatric assessment in older people : an umbrella review of health outcomes

Background: Comprehensive geriatric assessment (CGA) has been in use for the last three decades. However, some doubts remain regarding its clinical use. Therefore, we aimed to capture the breadth of outcomes reported and assess the strength of evidence of the use of comprehensive geriatric assessment (CGA) for health outcomes in older Methods: Umbrella review of systematic reviews of the use of CGA in older adults searching in Pubmed, Embase, Scopus, Cochrane library and CINHAL until 05 November 2021. All possible health outcomes were eligible. Two independent reviewers extracted key data. The grading of evidence was carried out using the GRADE for intervention studies, whilst data regarding systematic reviews were reported as narrative findings. Results: Among 1,683 papers, 31 systematic reviews (19 with meta-analysis) were considered, including 279,744 subjects. Overall, 13/53 outcomes were statistically significant (P < 0.05). There was high certainty of evidence that CGA reduces nursing home admission (risk ratio [RR] = 0.86; 95% confidence interval [CI]: 0.75–0.89), risk of falls (RR = 0.51; 95%CI: 0.29–0.89), and pressure sores (RR = 0.46; 95%CI: 0.24–0.89) in hospital medical setting; decreases the risk of delirium (OR = 0.71; 95%CI: 0.54–0.92) in hip fracture; decreases the risk of physical frailty in community-dwelling older adults (RR = 0.77; 95%CI: 0.64–0.93). Systematic reviews without meta-analysis indicate that CGA improves clinical outcomes in oncology, haematology, and in emergency department. Conclusions: CGA seems to be beneficial in the hospital medical setting for multiple health outcomes, with a high certainty of evidence. The evidence of benefits is less strong for the use of CGA in other settings