The origin of overpotential in lithium-mediated nitrogen reduction

The verification of the lithium-mediated nitrogen reduction system in 2019 has led to an explosion in the literature focussing on improving the metrics of faradaic efficiency, stability, and activity. However, while the literature acknowledges the vast intrinsic overpotential for nitrogen reduction due to the reliance on in situ lithium plating, it has thus far been difficult to accurately quantify this overpotential and effectively analyse further voltage losses. In this work, we present a simple method for determining the Reversible Hydrogen Electrode (RHE) potential in the lithium-mediated nitrogen reduction system. This method allows for an investigation of the Nernst equation and reveals sources of potential losses. These are namely the solvation of the lithium ion in the electrolyte and resistive losses due to the formation of the solid electrolyte interphase. The minimum observed overpotential was achieved in a 0.6 M LiClO4, 0.5 vol% ethanol in tetrahydrofuran electrolyte. This was −3.59 ± 0.07 V vs. RHE, with a measured faradaic efficiency of 6.5 ± 0.2%. Our method allows for easy comparison between the lithium-mediated system and other nitrogen reduction paradigms, including biological and homogeneous mechanisms

Early Life Socioeconomic Circumstance and Late Life Brain Hyperintensities : A Population Based Cohort Study

Funding: Image acquisition and image analysis for this study was funded by the Alzheimer's Research Trust (now Alzheimer's Research UK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments The authors would like to thank the participants of the Aberdeen 1936 Birth Cohort (ABC36), without whom this research would not have been possible.Peer reviewedPublisher PD

The role of ion solvation in lithium mediated nitrogen reduction

Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase (SEI) properties. In this study, we discover that the salt concentration has a remarkable effect on electrolyte stability: at concentrations of 0.6 M LiClO4 and above the electrode potential is stable for at least 12 hours at an applied current density of −2 mA cm−2 at ambient temperature and pressure. Conversely, at the lower concentrations explored in prior studies, the potential required to maintain a given N2 reduction current increased by 8 V within a period of 1 hour under the same conditions. The behaviour is linked more coordination of the salt anion and cation with increasing salt concentration in the electrolyte observed via Raman spectroscopy. Time of flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy reveal a more inorganic, and therefore more stable, SEI layer is formed with increasing salt concentration. A drop in faradaic efficiency for nitrogen reduction is seen at concentrations higher than 0.6 M LiClO4, which is attributed to a combination of a decrease in nitrogen solubility and diffusivity as well as increased SEI conductivity as measured by electrochemical impedance spectroscopy

Mapping competencies taught in public health – Experience of the Europubhealth Consortium

International audienceBackground Public health education aims at producing a competent workforce. The WHO-ASPHER framework proposes a set of relevant public health competencies organised in 10 sections (e.g. science practice, leadership, law policies and ethics etc). As part of the Europubhealth consortium (EPHc), eight universities collaborate for the delivery of a 2-year international public health master course. The course includes a first-year, or foundation component (4 options), and a second-year or specialisation component (7 options). Objectives In 2020, EPHc decided to use the framework in order to map the competencies addressed, and the level of proficiency aimed at, by each Y1 and Y2 option of the Master. To that end, component's coordinators answered an 84-item questionnaire covering the whole framework. Answers were summarised by calculating mean proficiency levels for each competency section. Results There were differences in overall proficiency levels between years with, as expected, higher scores in Y2. Options in Y1 reached medium to high proficiency scores for the sections “science practice”, “health promotion” and “communication” with scores of 2.6 to 3 (on a 1 to 4 scale). When compared with Y1 on a heat-map, Y2 options displayed more contrasted profiles, typically focussing (i.e. scores > 3.5) on 3 out of the 10 sections of competencies. Except for the “collaborations and partnership” section, the training pathways offered by the EPHc seem to offer opportunities for a high proficiency level in all domains of competencies. Conclusions The mapping proved a useful exercise to identify strengths and complementarities among the EPHc. The results suggest that the EPHc master course is coherent and offers students opportunities to gain proficiency in most competencies relevant to public health practice. Key messages • Competency-based education is likely to shape the future public health workforce. • The WHO-ASPHER framework proved a useful tool to map public health competencies addressed in the teaching of the Europubhealth international Master

Increased osteoclastic activity in acute Charcot’s osteoarthopathy: the role of receptor activator of nuclear factor-kappaB ligand

Aims/hypothesis: Our aims were to compare osteoclastic activity between patients with acute Charcot's osteoarthropathy and diabetic and healthy controls, and to determine the effect of the receptor activator of nuclear factor-kappaB ligand (RANKL) and its decoy receptor osteoprotegerin (OPG). Methods: Peripheral blood monocytes isolated from nine diabetic Charcot patients, eight diabetic control and eight healthy control participants were cultured in the presence of macrophage-colony stimulating factor (M-CSF) alone, M-CSF and RANKL, and also M-CSF and RANKL with excess concentrations of OPG. Osteoclast formation was assessed by expression of tartrate-resistant acid phosphatase on glass coverslips and resorption on dentine slices. Results: In cultures with M-CSF, there was a significant increase in osteoclast formation in Charcot patients compared with healthy and diabetic control participants (p=0.008). A significant increase in bone resorption was also seen in the former, compared with healthy and diabetic control participants (p<0.0001). The addition of RANKL to the cultures with M-CSF led to marked increase in osteoclastic resorption in Charcot (from 0.264±0.06% to 41.6±8.1%, p<0.0001) and diabetic control (0.000±0.00% to 14.2±16.5%, p<0.0001) patients, and also in healthy control participants (0.004±0.01% to 10.5±1.9%, p0.0001). Although the addition of OPG to cultures with M-CSF and RANKL led to a marked reduction of resorption in Charcot patients (41.6±8.1% to 5.9±2.4%, p=0.001), this suppression was not as complete as in diabetic control patients (14.2±16.5% to 0.45±0.31%, p=0.001) and in healthy control participants (from 10.5±1/9% to 0.00±0.00%, p<0.0001). Conclusions/interpretation: These results indicate that RANKL-mediated osteoclastic resorption occurs in acute Charcot's osteoarthropathy. However, the incomplete inhibition of RANKL after addition of OPG also suggests the existence of a RANKL-independent pathway

National support to public health research: a survey of European ministries

Background: Within SPHERE (Strengthening Public Health Research in Europe), a collaborative study funded by the European Commission, we have assessed the support for public health research at ministry level in European countries. Methods: We surveyed the health and science ministries in 25 EU countries and 3 EEA countries, using a broad definition of public-health research at population level. We made over 600 phone calls and emails to identify respondents and to gain answers. We gained formal replies from 42 out of 56 ministries (73% response) in 25 countries. There were 22 completed questionnaires (from 25 ministries), 6 short answers and 11 contacts declaring that their ministries were not responsible for public health research, while in 14 ministries (both ministries in three countries) no suitable ministry contact could be found. Results: In most European countries, ministries of health, or their devolved agencies, were regarded as the leading organizations. Most ministries were able to specify thematic areas for public-health research (from three to thirty), and others ministries referred to policy documents, health plans or public-health plans to define research priorities. Ministries and their agencies led on decisions for financial support of public-health research, with less involvement of other external organisations compared with the process of identifying priorities. However, the actual funds available for public health were not easily identifiable. Most ministries relied on general academic means for dissemination of results of public-health research, while ministries get information on the use of public-health research usually through informal means. Ministries made suggestions for strengthening public-health research through initiatives of their own countries and of the European Union: as well as more resources, improving coordination was most frequently suggested. Conclusion: There is no common approach to support for public-health research across Europe, and significant gaps in organisation and funding. Health ministries and national agencies value exchange between researchers and policy-makers, civil society organizations, and academic and public authorities, and the application of public-health research results. There would be benefits from better processes of priority setting and improved coordination for research, at regional, national and European levels