CO2 Electroreduction on Silver Catalysts Under Controlled Mass Transport Conditions

The electrochemical reduction of carbon dioxide (CO2RR) to value-added chemicals using excess intermittent electric power from renewable energy sources is considered a promising approach to mitigate global warming caused by anthropogenic CO2 emissions. The product selectivity of the CO2RR can be controlled by the chemical nature and the morphology of the catalyst material. Among the various products of the CO2RR, the production of carbon monoxide (CO) is highly desirable because it can be used as feedstock in the Fischer–Tropsch synthesis to produce higher long-chain hydrocarbons and alcohols. Silver is well known as a promising catalyst material for CO production. Most of the screening experiments to test the activity, selectivity, and stability of an electrocatalyst have been carried out in H-type cell configurations using aqueous electrolytes. However, the low solubility of CO2 in aqueous electrolytes under ambient conditions imposes severe mass transport limitations. This PhD thesis has addressed this challenge, by carrying out classical half-cell measurements in aqueous environments extended to a zero-gap gas-fed electrolyzer. The catalytic properties of two colloidal silver nanomaterials with different morphologies were studied (nanocubes and nanowires). The electrocatalysts studied herein present high selectivity and activity towards CO formation, e.g., in the case of silver nanocubes, a partial current density of ~625 mA cm−2 and a faradaic efficiency of ~85% for CO were attained. Besides, it is particularly pointed out that the reaction environment plays an essential role in the product distribution of the reaction; formate is generated with higher selectivities and activities in a highly alkaline environment than in a weak one. Furthermore, identical location scanning electron microscopy (IL-SEM) is herein demonstrated as a powerful technique to study the structural degradation of the electrocatalysts. By imaging the same spot on the catalyst before and after the CO2RR, it is possible to directly visualize changes of the catalyst morphology on a nm-length scale attributed to the electrolysis reaction. Limitations of this analysis technique are discussed based on surfactant-protected nanocatalysts. Additionally, a new electrochemical surfactant removal method based on potentiostatic CO2RR electrolysis was developed to remove polyvinylpyrrolidone or PVP (the capping agent) from Ag nanowire and nanocube surfaces, resulting in a substantially improved selectivity towards CO formation. Overall, the studies presented herein clearly demonstrate the importance of performing CO2RR under more realistic conditions to bring this process closer to what is needed for the scale-up of this reaction, which means that high faradaic efficiencies, partial current densities, and long stability are pursued

Modelado de la dispersión de luz por bacterias en contacto con nanopartículas de plata

"En este trabajo abordamos como tema principal de estudio la respuesta óptica de una bacteria con nanopartículas de plata (NPs Ag) sobre su superficie. Para realizar un estudio sistemático primero estudiamos las eficiencias de una bacteria sola, después la respuesta óptica de un arreglo de NPs Ag en diferentes posiciones y finalmente sistemas de bacteria-nanopartículas. Modelamos las eficiencias ópticas de absorción, dispersión y extinción de los sistemas de interés empleando la aproximación de dipolo discreto. Calculamos el patrón de dispersión de luz por una bacteria Staphylococcus aureus (S. aureus, gram-positiva), cuya principal característica es su morfología esférica, consideramos bacterias de diferente diámetro y composición, esto último a través de un modelo sencillo para estimar un índice de refracción efectivo asociado a la compleja composición de la bacteria. Estudios similares se realizaron para una bacteria Escherichia coli (E. coli, gram-negativa) con morfología esferocilíndrica. Del análisis de nuestros resultados concluimos que a mayor tamaño, los patrones de dispersión presentan un mayor número de mínimos. Además, bacterias con diferente composición presentan patrones de dispersión con el mismo número de mínimos y solo varían ligeramente sus intensidades. Se estudiaron arreglos de NPs Ag con 4, 5, 10, 15 y 30 partículas en diferentes distribuciones espaciales. Del análisis de los cálculos de las eficiencias ópticas se logró identificar que la línea espectral de la eficiencia de absorción tiene un máximo entre 400 y 410 nm. La intensidad de los espectros aumenta a medida que aumenta el número de NPs Ag. El sistema bacteria-NPs se estudio considerando una bacteria S. aureus con NPs de Ag sobre su superficie, considerando los arreglos mencionados anteriormente. La interacción bacteria-nanopartículas tiene como principal característica líneas espectrales similares a las de los arreglos de NPs solas, pero con intensidades 100 veces menores.

Unwrap Them First: Operando Potential- induced Activation Is Required when Using PVP-Capped Ag Nanocubes as Catalysts of CO2 Electroreduction

Metallic nanoparticles of different shape can be used as efficient electrocatalysts for many technologically and environmentally relevant processes, like the electroreduction of CO2. Intense research is thus targeted at finding the morphology of nanosized features that best suits catalytic needs. In order to control the shape and size distribution of the designed nanoobjects, and to prevent their aggregation, synthesis routes often rely on the use of organic capping agents (surfactants). It is known, however, that these agents tend to remain adsorbed on the surface of the synthesized nanoparticles and may significantly impair their catalytic performance, both in terms of overall yield and of product selectivity. It thus became a standard procedure to apply certain methods (e.g. involving UV-ozone or plasma treatments) for the removal of capping agents from the surface of nanoparticles, before they are used as catalysts. Proper design of the operating procedure of the electrocatalysis process may, however, render such cleaning steps unnecessary. In this paper we use poly-vinylpyrrolidone (PVP) capped Ag nanocubes to demonstrate a mere electrochemical, operando activation method. The proposed method is based on an observed hysteresis of the catalytic yield of CO (the desired product of CO2 electroreduction) as a function of the applied potential. When as-synthesized nanocubes were directly used for CO2 electroreduction, the CO yield was rather low at moderate overpotentials. However, following a potential excursion to more negative potentials, most of the (blocking) PVP was irreversibly removed from the catalyst surface, allowing a significantly higher catalytic yield even under less harsh operating conditions. The described hysteresis of the product distribution is shown to be of transient nature, and following operando activation by a single 'break-in' cycle, a truly efficient catalyst was obtained that retained its stability during long hours of operation

The capping agent is the key: Structural alterations of Ag NPs during CO2 electrolysis probed in a zero-gap gas-flow configuration

We apply silver nanoparticles (Ag NPs) as catalysts of CO2reduction in a zero-gap gas-flow electrolyser.Ag NPs stabilized by different ligands —branched polyethylenimine (BPEI), polyvinylpyrrolidone (PVP),polyethylene glycol (PEG), and citrate— are used in the experiments. The as-prepared NPs have almostidentical initial size distributions, yet their catalytic performance, in terms of achievable current andCO selectivity, is different. During electrolysis all Ag NPs exhibit unambiguous morphology changes;the degradation pathway they follow, however, markedly depends on the chemical nature of the cappingagent stabilizing them. Scanning electron micrographs obtained before and after constant-charge elec-trolyses carried out at different potentials reveal that amongst the studied ligands, BPEI seems to bethe most effective stabilizer of Ag NPs; in turn, however, BPEI also limits CO formation the most. In caseof PVP, mostly corrosion (particle shrinkage) is observed at practically relevant electrolysing potentials,while the application of PEG leads more to particle coalescence. Ostwald ripening seems to appear only athigh applied (H2forming) potentials in case of the three afore-mentioned ligands while in case of citrateit becomes significant already at mild (CO forming) voltages. By studying the effects of capping agentremoval and exchange we demonstrate that apart from ligands directly attached to the Ag NPs, alsothe excess of capping agents (adsorbed on the electrode surface) plays a decisive role in determiningthe extent and mode of catalyst degradation. The results of SEM-based particle sizing are also confirmedby synchrotron based wide-angle X-ray scattering measurements that provide further insight into theevolution of crystallite size and lattice strain in the applied Ag NPs during electrolysis

CartoCell, a high-content pipeline for 3D image analysis, unveils cell morphology patterns in epithelia

Decades of research have not yet fully explained the mechanisms of epithelial self-organization and 3D packing. Single-cell analysis of large 3D epithelial libraries is crucial for understanding the assembly and function of whole tissues. Combining 3D epithelial imaging with advanced deep-learning segmentation methods is essential for enabling this high-content analysis. We introduce CartoCell, a deep-learning-based pipeline that uses small datasets to generate accurate labels for hundreds of whole 3D epithelial cysts. Our method detects the realistic morphology of epithelial cells and their contacts in the 3D structure of the tissue. CartoCell enables the quantification of geometric and packing features at the cellular level. Our single-cell cartography approach then maps the distribution of these features on 2D plots and 3D surface maps, revealing cell morphology patterns in epithelial cysts. Additionally, we show that CartoCell can be adapted to other types of epithelial tissues.Ministerio de Ciencia e Innovación PID2019-103900GB-I00, PID2020-120367GB-I00, PID2021-126701OB-I00Junta de Andalucía US-1380953, PY18-631Ministerio de Economía y Competitividad BES-2022-07778

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

re-habitar El Carmen : Un proyecto sobre patrimonio contemporáneo

El proyecto _re-HABITAR suponía para el propio proceder de la institución un avance más allá del reconocimiento, registro, inventario o protección patrimonial de la arquitectura del siglo XX y del Movimiento Moderno para posicionarse en la acción preventiva y conservativa de ese legado contemporáneo. Para ello, la praxis patrimonial se aferraba a un modelo: el de la vivienda social en España en la segunda mitad del siglo XX; a un caso concreto: el de la barriada de Nuestra Señora del Carmen (Recasens Méndez-Queipo de Llano, 1958); y a un requisito fundamental: analizar un objeto vivo y en uso, aún con la presencia de quienes lo vivieron y usaron desde su origen

Self-Standing Metal Foam Catalysts for Cathodic Electro-Organic Synthesis.

Although electro-organic synthesis is currently receiving renewed interest because of its potential to enable sustainability in chemical processes to value-added products, challenges in process development persist: For reductive transformations performed in protic media, an inherent issue is the limited choice of metallic cathode materials that can effectively suppress the parasitic hydrogen evolution reaction (HER) while maintaining a high activity towards the targeted electro-organic reaction. Current development trends are aimed at avoiding the previously used HER-suppressing elements (Cd, Hg and Pb) because of their toxicity. Here, we report the rational design of highly porous foam-type binary and ternary electrocatalysts with reduced Pb content. Optimized cathodes are tested in electro-organic reductions using an oxime to nitrile transformation as a model reaction relevant for the synthesis of fine chemicals. Their electrocatalytic performance is compared with that of the model CuSn7Pb15 bronze alloy that has recently been endorsed as the best cathode replacement for bare Pb electrodes. All developed metal foam catalysts outperform both bare Pb and the CuSn7Pb15 benchmark in terms of chemical yield and energetic efficiency. Moreover, post-electrolysis analysis of the crude electrolyte mixture and the cathode's surfaces through ICP-MS and SEM, respectively, reveal the foam catalysts' elevated resistance to cathodic corrosion. This article is protected by copyright. All rights reserved