Transitions of lithium occupation in graphite:A physically informed model in the dilute lithium occupation limit supported by electrochemical and thermodynamic measurements

Understanding the role of the phase transitions during lithiation and delithiation of graphite remains a problem of fundamental importance, but also practical relevance owing to its widespread use as the anode material in most commercial lithium-ion cells. Previously performed density functional theory (DFT) calculations show a rapid change in the lithium-carbon interaction at low occupation, due to partial charge transfer from Li to C. We integrate this effect in our previously developed two level mean field model, which describes the Stage I – Stage II transition in graphite. The modified model additionally describes the most predominant transition that occurs at low Li content in graphite, which results in a previously unexplained feature in voltage and dQ/dV profiles, and thermodynamic measurements of partial molar enthalpy. In contrast with the Stage I-Stage II transition, this extra feature is not associated with observable features in the partial molar entropy and our model demonstrates why. There is a sharp change in the open circuit voltage at very low Li occupation, followed by a transition to a voltage plateau (peak in dQ/dV). The behaviour arises due to the contrasting effects of the partial molar entropy and enthalpy terms on the partial molar Gibbs energy and hence cell voltage. Hence the voltage profile and phase transitions can be approximated for all lithium occupations, potentially allowing a predictive capability in cell level models

Red “Universidad, género, docencia e igualdad”

La Red de investigación en docencia universitaria “Universidad, docencia, genero e igualdad” persigue avanzar en la calidad e innovación de las enseñanzas universitarias a partir de la inclusión de la perspectiva de género. Se busca dar cumplimiento a las directrices generales de los nuevos planes de estudio respecto del principio de igualdad de oportunidades entre hombres y mujeres en la formación universitaria (Real Decreto 1393/2007. BOE nº 260, 30 de octubre de 2007). En la quinta edición de la Red, y dada su composición multidisciplinar, se ha trabajado en tres líneas de investigación: 1) mantenimiento del “Portal web con recursos docentes con perspectiva de género”, proyecto financiado por el Instituto de la Mujer (PACUI, 2012) e iniciado en el curso 2012-2013; 2) desarrollo de la primera versión de “iLengUA”, una herramienta informática para un discurso inclusivo e igualitario; y 3) diseño de una Guía de recomendaciones para la inclusión de la perspectiva de género en la docencia universitaria

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

The Graphene Ring Nanoelectrode (GRiN) and its Application as an Electroanalytical Sensor for Environmental Monitoring

Nanoelectrochemistry is the study of the electrochemical properties of materials with at least one dimension of nanometer size, which can be classified as Faradaic and non-Faradaic processes. In case of the former, the charge is exchanged between the electrolyte/electrode interface by electron transfer processes, causing redox reactions. In case of the latter, there is no charge transfer between the interface, and redox reactions do not occur, but this still involves the charging and discharging of the interface, the so-called diffuse double layer. These processes are exploited in applications such as metrology (electroanalytical sensors), energy storage (e.g. supercapacitors, fuel cells), scanning probe microscopy, molecular electronics (single molecule electrochemistry) and biological studies on cells. The exploitation of nanoelectrode properties depends critically upon reliable and robust electrode fabrication of well-defined electroactive area geometry whose size approaches molecular dimensions. 2D materials, such as graphene, offer new possibilities in terms of nanoelectrode design and electrode material thickness on the nano regime. Graphene, with a monoatomic layer of 0.344 nm, offers easy fabrication, high conductivity and high electrochemical activity – mainly on the edge sites. The electrochemistry of carbon-based materials is well-known and utilised for sensor and battery applications, whereas new studies on the physical properties of graphene have paved the way for its use in electronics applications, amongst other fields. The electrochemistry of graphene, however, has not been studied as extensively. Thus, the aim of the investigation presented in this thesis was four fold; to optimise graphene ring nanoelectrode (GRiN) / graphene ring microelectrode (GRiME) electrode fabrication by further decreasing the electrode thickness and exploiting the ring geometry and electrical properties of graphene; to characterise the electrode material and devices using physical and electrochemical techniques; to study the electrochemical performance of the device by investigating the electron transfer processes taking place at the nanoelectrode surface; and to test the device in the application of electroanalytical sensor for the detection of mercury. Based on the design of a thin ring nanoelectrode, the graphene ring nanoelectrode (GRiN) is a novel device which permits the exploitation of graphene edge sites as an electrode material to study electron transfer processes in the nano regime. The GRiN is also the first instance in which a solely-graphene-based nanoelectrode is applied for the detection of mercury as well as for the study of the heterogenous electron transfer rate constant (k0) for the outer-sphere redox probe of FCA-/FCA0. The fabrication and characterisation of Graphene Ring Nanoelectrodes (GRiNs) at size ranges below 10 nm is presented. Graphene is obtained from chemically exfoliated graphite oxide (GO) prepared by a modified Hummers’ method. GO is dipcoated from colloidal GO solution onto optical fibre and the consequential GO layer was reduced to graphene by both chemical (hydrazine) and thermal treatments. Subsequent electrical connections and isolation of the device were then carried out. Fabricated GRiNs are found to be conducting and, through the application of electrochemical sizing methods, were proven to have ring electrode thicknesses in the sub-5 nm range, specifically between 0.5 and 1 nm. Atomic force microscopy was used for corroboration of the physical sizing of GRiNs. Calculations of the heterogeneous electron transfer rate constant at GRiNs for the outer and inner-sphere redox probes, FCA-/FCA0 and Fe(CN)63-/Fe(CN)64-, respectively, have been measured over a different range of electrolyte concentrations and different electrode thicknesses. This demonstrates the effects of accessing the critical dimension of the nanoelectrodes on Faradaic electrochemistry. An application of GRiNs explored in this work is in the area of ion-selective electroanalytical sensors of environmentally important heavy metals, such as mercury, present in drinking water using Differential Pulse Stripping Voltammetry (DPSV). The capability of GRiNs to detect mercury at ppb levels is explored.

Fabrication and characterisation of graphene and its use in formation of Graphene Ring Microelectrodes (GRiMEs)

We report the fabrication, characterisation and use of graphene for the fabrication of Graphene Ring Microelectrodes (GRiMEs). Graphene was fabricated using a modified Hummers method and optimised hydrazine-thermal reduction procedure. So-formed graphene was characterised using measurement of light transmittance, sheet resistivity, droplet contact angle and AFM. GRiMEs were formed by dip coating fibre optics with GO followed by reduction to graphene. The behavior of the so-formed GRiMEs was studied using the probe redox system ferricyanide and electrode thicknesses assessed by physical methods using AFM operating in contact, lateral force and current sensing modes. Using 220 µm dia. fibre optics, ring electrode thicknesses ranging from 73.8 nm – 18 nm were obtained. The fabricated GRiMEs are highly reliable (i-v response invariant over >300 scans), the microring design allowing for efficient use of electrochemically active graphene edge sites. Further, the associated nA scale currents neatly obviate issues relating to the high resistivity of undoped graphene. Thus, the use of graphene in ring microelectrodes improves the reliability of existing microelectrode designs and expands the range of use of graphene-based electrochemical devices

Mapping and assessing ecosystem services in Europe's Overseas: A comparative analysis of MOVE case studies

International audienceMapping and Assessment of Ecosystems and their Services (MAES) has been widely applied on the European Union (EU) mainland, whereas the EU Overseas entities still bear potential for implementation. This paper presents novel applications of the MAES procedure in the EU Outermost Regions and Overseas Countries and Territories ("EU Overseas"). Eight case studies from different geographical areas were analysed through a comparative assessment by applying an established framework following key steps in the MAES process, in order to stipulate lessons learned and recommendations for MAES in the EU Overseas. These key steps include the identification of policy questions, stakeholder networks and involvement, application of MAES methods, dissemination and communication and implementation. The case studies were conducted and analysed under the umbrella of the EU MOVE pilot project, including the Azores, the Canary Islands, Saint Martin, French Guiana, Martinique, Reunion Island and the Falkland Islands. Each case study represented different governance, policy and decision-making frameworks towards biodiversity and environmental protection. Case studies predominantly addressed the policy domains of Nature and Biodiversity Conservation and Marine and Maritime Policy. Ecosystem Services (ES) were assessed across a wide range of themes, biomes and scales, focusing on terrestrial, coastal and marine ecosystems. Results show that the implementation of the case studies was accompanied by extensive communication and dissemination activities. First success stories were visible, where the MAES exercise led to meaningful uptake of the ES concept to policies and decision-making. Yet, there is still work to be done - major bottlenecks were identified related to the MAES implementation centring around financial resources, training and technical expertise. Addressing these aspects can contribute to an enhanced implementation of MAES in the EU Overseas in the future

Red “Universidad, género, docencia e igualdad”

La Red de investigación en docencia universitaria “Universidad, docencia, genero e igualdad” persigue avanzar en la calidad e innovación de las enseñanzas universitarias a partir de la inclusión de la perspectiva de género. Se busca dar cumplimiento a las directrices generales de los nuevos planes de estudio respecto del principio de igualdad de oportunidades entre hombres y mujeres en la formación universitaria (Real Decreto 1393/2007. BOE nº 260, 30 de octubre de 2007). En la quinta edición de la Red, y dada su composición multidisciplinar, se ha trabajado en tres líneas de investigación: 1) mantenimiento del “Portal web con recursos docentes con perspectiva de género”, proyecto financiado por el Instituto de la Mujer (PACUI, 2012) e iniciado en el curso 2012-2013; 2) desarrollo de la primera versión de “iLengUA”, una herramienta informática para un discurso inclusivo e igualitario; y 3) diseño de una Guía de recomendaciones para la inclusión de la perspectiva de género en la docencia universitaria