Neurological manifestations of COVID-19 in adults and children

Different neurological manifestations of coronavirus disease 2019 (COVID-19) in adults and children and their impact have not been well characterized. We aimed to determine the prevalence of neurological manifestations and in-hospital complications among hospitalized COVID-19 patients and ascertain differences between adults and children. We conducted a prospective multicentre observational study using the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) cohort across 1507 sites worldwide from 30 January 2020 to 25 May 2021. Analyses of neurological manifestations and neurological complications considered unadjusted prevalence estimates for predefined patient subgroups, and adjusted estimates as a function of patient age and time of hospitalization using generalized linear models. Overall, 161 239 patients (158 267 adults; 2972 children) hospitalized with COVID-19 and assessed for neurological manifestations and complications were included. In adults and children, the most frequent neurological manifestations at admission were fatigue (adults: 37.4%; children: 20.4%), altered consciousness (20.9%; 6.8%), myalgia (16.9%; 7.6%), dysgeusia (7.4%; 1.9%), anosmia (6.0%; 2.2%) and seizure (1.1%; 5.2%). In adults, the most frequent in-hospital neurological complications were stroke (1.5%), seizure (1%) and CNS infection (0.2%). Each occurred more frequently in intensive care unit (ICU) than in non-ICU patients. In children, seizure was the only neurological complication to occur more frequently in ICU versus non-ICU (7.1% versus 2.3%, P < 0.001). Stroke prevalence increased with increasing age, while CNS infection and seizure steadily decreased with age. There was a dramatic decrease in stroke over time during the pandemic. Hypertension, chronic neurological disease and the use of extracorporeal membrane oxygenation were associated with increased risk of stroke. Altered consciousness was associated with CNS infection, seizure and stroke. All in-hospital neurological complications were associated with increased odds of death. The likelihood of death rose with increasing age, especially after 25 years of age. In conclusion, adults and children have different neurological manifestations and in-hospital complications associated with COVID-19. Stroke risk increased with increasing age, while CNS infection and seizure risk decreased with age

De-risking and scaling strategies for PEM water electrolysis

Proton-exchange-membrane (PEM) water electrolysis is a crucial building block to tackle the challenges of future energy production. Besides the use of hydrogen as energy carrier, there is an emerging need for green hydrogen for various industrial processes e.g, in the steel industry and the chemical industry. Therefore, the German National Hydrogen Council (NWR) proposes a minimum demand in Germany for green Hydrogen of about 94 TWh in 2030 which in turn demands an electrolysis capacity of 39–52 GW1. This underlines the urgent need to increase electrolysis capacity in the future. Hydrogen generation by water electrolysis offers a variety of advantages as high current density, easy handling and maintenance and the possibility for a modular setup1. Besides all that, PEM-electrolysis is still in an early commercialization stage. Efficient De-Risking is a mandatory step to increase the speed in setting up electrolysis plants, which includes an understanding of ageing phenomena and degradation mechanisms. Nevertheless, a variety of degradation and ageing phenomena are reported for PEM electrolytic cells. But investigations on an industrially relevant scale are still hard to find and there is no reliable data available to investigate such phenomena.Here, we are focusing a multiscale approach in investigating ageing phenomena from a microscopic level to an industrially relevant scale in PEM electrolysis. Therefore, we perform various investigations such as electrochemical impedance spectroscopy (EIS), local conductivity measurements or determination of diffusion behavior in correlation with different operation parameters (flow rate, current density, etc). This is accompanied with extensive studies on post-test samples of membrane electrode assemblies (MEA). Different characterization methods such as electron microscopy (SEM, TEM), Atomic Force microscopy (AFM), X-ray computed tomography (XCT), Nuclear Magnetic resonance (NMR) and Raman spectroscopy as well as elastic scattering methods (XRD, SAXS) are used, to get a holistic picture of the ongoing changes in an electrolyzer during operation.References:1) German National Hydrogen Council: White Paper„ Update 2024: Greenhouse gas savings and the associated hydrogen demand in Germany”, 05th of May 2024. 2) Wang et al. Carbon Neutrality (2022) 1:21

De-Risking PEM-Electrolysis: Advanced Characterization for the Pathway Towards the GW-Scale

"Green" hydrogen, from carbon-neutral energy sources such as wind or solar energy, will play a key role in the decarbonization of the electrical grid and a vast number of industrial sectors1. To produce the large quantities of hydrogen that are needed to achieve this, Proton exchange membrane electrolytic cells (PEMEC) are one of the most promising technologies available right now. However, especially in long-term and dynamic operation, PEMEC can still be subject to various degradation phenomena, which is detrimental to their economic feasibility as a hydrogen source2,3. For an accelerated market ramp-up of PEMEC, a comprehensive de-risking of the technology is essential.Here, we present several of our efforts to accelerate the upscaling of PEMEC technology towards the GW scale for a "green" hydrogen economy. A central aspect for this is the investigation of degradation patterns in PEMEC from a laboratory scale level up to industrial scale PEM electrolyzers on a component, cell, and stack level. A degradation in the electrochemical performance of the PEMEC is determined by the observation of changes in the polarization curves and the electrochemical impedance spectroscopy (EIS) response after long-term cycling of the cells or stacks up to an industrially relevant scale. This is further refined by a variety of sensors in the test benches, e.g. for measuring the gas permeation through the membrane electrode assembly (MEA) among many others. This allows us to make generalized statements on the "State-of-health" of the PEMEC.To make even more in-depth statements on possible degradation phenomena, a variety of complementary analytical methods are used post-mortem on the MEA to elucidate on possible origins of the reduced performance. X-ray computed tomography (XCT) is used to determine morphological changes such as cracks, voids or foreign particles in both electrodes and the membrane of the MEA with micron resolution. Selectively performed cross-section analysis with focused ion beam (FIB) in combination with scanning/transmission electron microscopy (SEM/TEM) can provide more information on the possible origin of irregularities. More detailed studies of the electrode morphology and conductivity is obtained by general conductivity measurements under controlled humidity/temperature conditions on a macroscale, and by atomic force microscopy (AFM) on a micro- and nanoscale. To probe the properties of the PFSA membrane in different states, nuclear magnetic resonance spectroscopy (NMR) is used. To ascertain the quality of the MEA in the production line even before the use in a PEMEC, a Raman spectroscopy approach was used as an in-line compatible method.With the results of this comprehensive testing- and characterization approach and formulating novel approaches for online analytics in PEMEC manufacturing, we want to contribute the de-risking of PEM electrolysis for an acceleration of the technology implementation towards a GW-scale. This highlights the importance of fundamental spectroscopic and microscopic methods even for large industrial scale devices to improve PEMEC and achieve a more widespread adoption of the technology