A Pathway towards Pt-free Cathodes in High-Temperature Proton Exchange Membrane Fuel Cells

The high temperature proton exchange membrane fuel cell (HT-PEMFC) has several advantages compared to its low temperature (LT) counterpart. The typical operation temperature of 160 °C enables an easier heat management, and the omission of humidification. However, due to the partial blocking of the cathodic and anodic Pt catalyst by phosphates from the phosphoric acid-doped membrane, higher catalyst loadings compared to LT-PEMFC of 0.86 mgPt cm-2 per electrode are commonly employed.[1] To increase the competitiveness of HT-PEMFCs implementation of Fe-N-Cs is a promising option for reduction of catalyst costs. In this study, we give an overview about the application of different Fe-N-C catalysts in Pt free HT-PEMFC cathodes.[2] Moreover, we show their application in hybrid PtNi/C+Fe N C cathodes.[1] The complete replacement of Pt catalyst by Fe N C in the cathode results in low performance[2] and a strong voltage decay within the first 60 hours of HT-PEMFC operation. In contrast, a hybrid MEA with reduced Pt-loading displayed a more comparable performance to commercial MEA (Celtec®-P1200) and constant voltage over 60 h. Furthermore, it was found that the typical activation procedure of HT-PEMFC MEAs (around 60 h constant load) is not sufficient for hybrid MEAs. There, a voltage increase over the first 240 h of operation was observed.[1] These results give the basis for further optimization of Pt-free Fe N C electrodes. Furthermore, the potential of hybrid MEAs for Pt-loading reduction in HT-PEMFC is pointed out

The Dichotomous Pattern of IL-12R and IL-23R Expression Elucidates the Role of IL-12 and IL-23 in Inflammation

IL-12 and IL-23 cytokines respectively drive Th1 and Th17 type responses. Yet, little is known regarding the biology of these receptors. As the IL-12 and IL-23 receptors share a common subunit, it has been assumed that these receptors are co-expressed. Surprisingly, we find that the expression of each of these receptors is restricted to specific cell types, in both mouse and human. Indeed, although IL-12Rβ2 is expressed by NK cells and a subset of γδ T cells, the expression of IL-23R is restricted to specific T cell subsets, a small number of B cells and innate lymphoid cells. By exploiting an IL-12- and IL-23-dependent mouse model of innate inflammation, we demonstrate an intricate interplay between IL-12Rβ2 NK cells and IL-23R innate lymphoid cells with respectively dominant roles in the regulation of systemic versus local inflammatory responses. Together, these findings support an unforeseen lineage-specific dichotomy in the in vivo role of both the IL-12 and IL-23 pathways in pathological inflammatory states, which may allow more accurate dissection of the roles of these receptors in chronic inflammatory diseases in humans

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223

A blood atlas of COVID-19 defines hallmarks of disease severity and specificity.

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19

Large-scale sequencing identifies multiple genes and rare variants associated with Crohn’s disease susceptibility

peer reviewe

Connection of Bipolar Plate with Graphite Felt Electrode for Vanadium Flow Battery Using a Powder Thermal Unification Method

Carbon felt electrodes are usually compressed against the bipolar plates in order to decrease the contact resistance, but it leads to high pressure drop and consumption of pumping energy in conventional vanadium redox flow battery stacks. This paper describes the fabrication of an effective way to unify the bipolar plate and graphite felt electrode in order to improve the battery efficiency at lower felt compression pressure. The unification process involves a thermal fusion technique with a component design consisting of bipolar plate, graphite felt electrode and connecting powder. The powder comprises either polyvinylidene difluoride or a mixture of polyvinylidene difluoride and conductive carbon black. The interfacial bonding substance determines the electrical resistance of the resultant fabricated unified assembly. The electrical resistance results prove that the carbon black proportion in the bonding element substantially reduces the electrical resistance. The optimum quantity of carbon black in the powder is found to be 40 wt%. Microcomputed tomography analysis findings indicate that thermally unified assembly interfacial contact electrode porosity is slightly lower than that of an unbonded sample. A two-cell vanadium redox flow battery stack with integrated unified assembly achieves a rather constant energy efficiency of 76% during 100 cycles with 5% electrode compression at a current density of 80 mA cm−2

Comparative Study of Platinum Nanoparticle Deposition on TiO2/BP and SnO2/BP Nanocomposites for the Oxygen Reduction Reaction

For further commercialization of the proton exchange membrane fuel cell technology an improvement of the stability of commonly used Pt-based oxygen reduction reaction (ORR) catalysts is necessary. In this study SnO2- and TiO2-carbon nanocomposites using high surface area Black Pearls (BP) and commercial metal oxide nanoparticles were investigated as support materials for Pt. Homogenously distributed 40 wt.% Pt catalysts were obtained. When using TiO2-BP support an outstanding intrinsic activity but no stability improvement was observed, whereas the use of SnO2- BP as Pt support lead to a slightly lower ORR activity but an increased catalyst stability

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe-N-C in Pt-alloy Cathodes

Pt poisoning by phosphate in high temperature proton exchange membrane fuel cells (HT PEMFC) leads to loadings up to 1 mgPt cm-2 per electrode of costly materials. While cheaper Fe N C catalysts are unaffected by phosphate deactivation and contribute to the catalysis of the oxygen reduction reaction, their volumetric activity is substantially lower. In this study, the effect of Pt loading reduced hybrid cathodes for HT-PEMFC is investigated using commercial Celtec®-P-based assembling. A promising effect of Fe N C incorporation in terms of acid attraction and activity retention is found. A longer activation (230 h, 0.3 A cm-2) for the hybrid MEAs is necessary, due to the slower acid distribution within Fe N Cs. This study shows the potential of Pt-content reduction by up to 25 % compared to standard MEA using hybrid electrodes. Moreover, important insights for future strategies of cell activation are revealed for these hybrid MEAs