Engineering single-atom Fe-N active sites on hollow carbon spheres for oxygen reduction reaction

Seeking alternatives to noble metals-based electrocatalysts for oxygen reduction reaction (ORR), hollow carbon spheres (CSs) were finely tuned with stable single-atom Fe-N species through a synthesis methodology requiring only earth-abundant metal precursors. CSs with different sizes were synthesized by sol-gel polycondensation of resorcinol with formaldehyde over silica nanoparticles, followed by thermal annealing and silica etching. A catalyst screening revealed the positive impact of both the hollow core and structural defects of the CSs for ORR. Single-atom Fe-N active sites were introduced on the best performing CSs through simultaneous incorporation of iron and nitrogen precursors, and glucose. A significant enhancement in ORR activity was observed despite the small iron load introduced (0.12 wt%). ORR performance indicators, advanced characterization, and molecular simulation studies revealed nitrogen's crucial role in anchoring individual iron atoms and modulating the charge density nearby the active sites (increase of 80 mV in the half-wave potential). Adding glucose as a chelating agent enhances the metal-heteroatom coordination and subsequent dispersion of iron, accounting for an increase of 20 mV in the half-wave potential, an average of electrons transferred as high as 3.9 (at 0.4 V vs. RHE), and higher stability (99%) than that of a platinum-based (20 wt%) electrocatalyst (92%).11 página

Recensiones [Revista de Historia Económica Año V Otoño 1987 n. 3 pp. 601-647]

Françoise Dosse. L'histoire en miettes. Des «Annales» a la «nouvelle histoire» (Por Femando G. Jaén).-- Jerónimo López-Salazar Pérez. Estructuras agrarias y sociedad rural en La Mancha (siglos XVI-XVII) (Por Enrique Llopis).-- Agustín Guimera Ravina. Burguesía extranjera y comercio atlántico: la empresa comercial irlandesa en Canarias (1703-1771) (Por Pedro Pérez Herrero).-- JMiguel Molina Martínez.El Real Tribunal de Minería de Lima (1785-1821) (Por Kenneth J. Andrien).-- Bárbara A. Tenenbaum. México en la época de los agiotistas, 1821-1857 (Por Inmaculada Romero-Hombrebucno).-- Joan Boadas i Raset. Girona després de la Guerra de Successió. Riquesa urbana i estructura social al primer quart del segle XVIII (Por Enriqueta Camps).-- V. Pinilla Navarro. Teruel (1833-1868). Revolución burguesa y atraso económico (Por M. Teresa Pérez Picazo).-- Jordi Nadal y otros. Catalunya, la fabrica d'Espanya (Un siglo de industrialización catalana, 1833-1936) (Por Sebastián Coll Martín).-- J. SardáDexeus. Escritos (1948-1980) (Por Pablo Martín Aceña).-- Esperanza Frax. Puertos y comercio de cabotaje en España, 1857-1934 y El mercado interior y los principales puertos, 1857-1920 (Por A. Gómez Mendoza).-- Vicent Soler Marco. Guerra i expansió industrial: Pais Valencia (1914-1923) (Por Albert Carreras).-- Guillermo Cortázar. Alfonso XIII, hombrede negocios. Persistencia del Antiguo Régimen, modernización económica y crisis política, 1902-1931 (Por Gabriel Tortella).-- S. N. Broadberry The British Economy between the Wars. A Macroeconomic Survey (Por Francisco Comín)Publicad

Smoking cessation opportunities in severe mental illness (tobacco intensive motivational and estimate risk — TIMER—): study protocol for a randomized controlled trial

There is an increased risk of premature death in people with severe mental illness (SMI). Respiratory disorders and cardiovascular disease are leading causes of increased mortality rates in these patients, and tobacco consumption remains the most preventable risk factor involved. Developing new tools to motivate patients towards cessation of smoking is a high priority. Information on the motivational value of giving the lung age and prevention opportunities is unknown in this high-risk population. In the context of community care, screening and early detection of lung damage could potentially be used, together with mobile technology, in order to produce a prevention message, which may provide patients with SMI with a better chance of quitting smoking.This study receives funding by the Spanish Ministry of Economy, Industry and Competitiveness, Instituto Carlos III (FIS PI16/00802)

Global attitudes in the management of acute appendicitis during COVID-19 pandemic: ACIE Appy Study

Background: Surgical strategies are being adapted to face the COVID-19 pandemic. Recommendations on the management of acute appendicitis have been based on expert opinion, but very little evidence is available. This study addressed that dearth with a snapshot of worldwide approaches to appendicitis. Methods: The Association of Italian Surgeons in Europe designed an online survey to assess the current attitude of surgeons globally regarding the management of patients with acute appendicitis during the pandemic. Questions were divided into baseline information, hospital organization and screening, personal protective equipment, management and surgical approach, and patient presentation before versus during the pandemic. Results: Of 744 answers, 709 (from 66 countries) were complete and were included in the analysis. Most hospitals were treating both patients with and those without COVID. There was variation in screening indications and modality used, with chest X-ray plus molecular testing (PCR) being the commonest (19\ub78 per cent). Conservative management of complicated and uncomplicated appendicitis was used by 6\ub76 and 2\ub74 per cent respectively before, but 23\ub77 and 5\ub73 per cent, during the pandemic (both P < 0\ub7001). One-third changed their approach from laparoscopic to open surgery owing to the popular (but evidence-lacking) advice from expert groups during the initial phase of the pandemic. No agreement on how to filter surgical smoke plume during laparoscopy was identified. There was an overall reduction in the number of patients admitted with appendicitis and one-third felt that patients who did present had more severe appendicitis than they usually observe. Conclusion: Conservative management of mild appendicitis has been possible during the pandemic. The fact that some surgeons switched to open appendicectomy may reflect the poor guidelines that emanated in the early phase of SARS-CoV-2