COVID-19: poverty has led to greater welfare loss than ill health in many low-income countries

Global welfare has taken a turn for the worse in the age of COVID, with both health and income levels under threat. Francisco Ferreira, Olivier Sterck, Daniel Gerszon Mahler, and Benoit Decerf estimate the worldwide mortality and poverty generated by the pandemic and compare these two sources of welfare losses by expressing them in a common metric: years of human life. Their analysis shows that for most poor and middle-income countries, greater economic deprivation has been a more important source of loss in well-being than premature death

Lives and livelihoods: estimates of the global mortality and poverty effects of the Covid-19 pandemic

This paper evaluates the global welfare consequences of increases in mortality and poverty generated by the Covid-19 pandemic. Increases in mortality are measured in terms of the number of years of life lost (LY) to the pandemic. Additional years spent in poverty (PY) are conservatively estimated using growth estimates for 2020 and two dif-ferent scenarios for its distributional characteristics. Using years of life as a welfare metric yields a single parameter that captures the underlying trade-off between lives and livelihoods: how many PYs have the same welfare cost as one LY. Taking an agnostic view of this parameter, estimates of LYs and PYs are compared across countries for different scenarios. Three main findings arise. First, as of early June 2020, the pandemic (and the observed private and policy responses) has generated at least 68 million additional poverty years and 4.3 million years of life lost across 150 countries. The ratio of PYs to LYs is very large in most coun-tries, suggesting that the poverty consequences of the crisis are of paramount importance. Second, this ratio declines systematically with GDP per capita: poverty accounts for a much greater share of the welfare costs in poorer countries. Finally, the dominance of poverty over mortality is reversed in a counterfactual “herd immunity” scenario: without any policy intervention, LYs tend to be greater than PYs, and the overall welfare losses are greater

Ligand-Induced Incompatible Curvatures Control Ultrathin Nanoplatelet Polymorphism and Chirality

The ability of thin materials to shape-shift is a common occurrence that leads to dynamic pattern formation and function in natural and man-made structures. However, harnessing this concept to design inorganic structures at the nanoscale rationally has remained far from reach due to a lack of fundamental understanding of the essential physical components. Here, we show that the interaction between organic ligands and the nanocrystal surface is responsible for the full range of chiral shapes seen in colloidal nanoplatelets. The adsorption of ligands results in incompatible curvatures on the top and bottom surfaces of NPL, causing them to deform into helico\"ids, helical ribbons, or tubes depending on the lateral dimensions and crystallographic orientation of the NPL. We demonstrate that nanoplatelets belong to the broad class of geometrically frustrated assemblies and exhibit one of their hallmark features: a transition between helico\"ids and helical ribbons at a critical width. The effective curvature $\bar{\kappa}$ is the single aggregate parameter that encodes the details of the ligand/surface interaction, determining the nanoplatelets' geometry for a given width and crystallographic orientation. The conceptual framework described here will aid the rational design of dynamic, chiral nanostructures with high fundamental and practical relevance.Comment: 16 pages, 8 figure

Investigation of salicylate hepatic responses in comparison with chemical analogues of the drug

AbstractAnti-hyperglycaemic effects of the hydroxybenzoic acid salicylate might stem from effects of the drug on mitochondrial uncoupling, activation of AMP-activated protein kinase, and inhibition of NF-κB signalling. Here, we have gauged the contribution of these effects to control of hepatocyte glucose production, comparing salicylate with inactive hydroxybenzoic acid analogues of the drug. In rat H4IIE hepatoma cells, salicylate was the only drug tested that activated AMPK. Salicylate also reduced mTOR signalling, but this property was observed widely among the analogues. In a sub-panel of analogues, salicylate alone reduced promoter activity of the key gluconeogenic enzyme glucose 6-phosphatase and suppressed basal glucose production in mouse primary hepatocytes. Both salicylate and 2,6 dihydroxybenzoic acid suppressed TNFα-induced IκB degradation, and in genetic knockout experiments, we found that the effect of salicylate on IκB degradation was AMPK-independent. Previous data also identified AMPK-independent regulation of glucose but we found that direct inhibition of neither NF-κB nor mTOR signalling suppressed glucose production, suggesting that other factors besides these cell signalling pathways may need to be considered to account for this response to salicylate. We found, for example, that H4IIE cells were exquisitely sensitive to uncoupling with modest doses of salicylate, which occurred on a similar time course to another anti-hyperglycaemic uncoupling agent 2,4-dinitrophenol, while there was no discernible effect at all of two salicylate analogues which are not anti-hyperglycaemic. This finding supports much earlier literature suggesting that salicylates exert anti-hyperglycaemic effects at least in part through uncoupling

Tunable Supramolecular Hydrogels for Selection of Lineage-Guiding Metabolites in Stem Cell Cultures

Stem cells are known to differentiate in response to the chemical and mechanical properties of the substrates on which they are cultured. Thus, supramolecular biomaterials with tunable properties are well suited for the study of stem cell differentiation. In this report, we exploited this phenomenon by combining stem cell differentiation in hydrogels with variable stiffness and metabolomics analysis to identify specific bioactive lipids that are uniquely used up during differentiation. To achieve this, we cultured perivascular stem cells on supramolecular peptide gels of different stiffness, and metabolite depletion followed. On soft (1 kPa), stiff (13 kPa), and rigid (32 kPa) gels, we observed neuronal, chondrogenic, and osteogenic differentiation, respectively, showing that these stem cells undergo stiffness-directed fate selection. By analyzing concentration variances of >600 metabolites during differentiation on the stiff and rigid gels (and focusing on chondrogenesis and osteogenesis as regenerative targets, respectively), we identified that specific lipids (lysophosphatidic acid and cholesterol sulfate, respectively), were significantly depleted. We propose that these metabolites are therefore involved in the differentiation process. In order to unequivocally demonstrate that the lipid metabolites that we identified play key roles in driving differentiation, we subsequently demonstrated that these individual lipids can, when fed to standard stem cell cultures, induce differentiation toward chondrocyte and osteoblast phenotypes. Our concept exploits the design of supramolecular biomaterials as a strategy for discovering cell-directing bioactive metabolites of therapeutic relevance

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Synthèse et caractérisation de nanocristaux colloïdaux de semiconducteurs II-VI à structure coeur/coque. Contrôle de la cristallinité et des propriétés d'émission.

We have developed synthesis protocols of core/shell semiconductors nanocrystals in CdSe/CdS and CdSe/CdS/ZnS. The perfectly crystalline shell improve the fluorescence properties of the nanocrystals as well as their resistance to environment modifications. We have shown that the crystal structure can be choose and controlled during synthesis by a judicious choice of the surface ligands. Moreover, we show that the fluorescence blinking of such nanocrystals can be strongly reduced or even suppressed if we synthesize core/shell CdSe/CdS nanocrystals with a sufficiently thick CdS shell. These objects are studied in single particle experiments. Fluorescence and lifetime measurements allow us to identify the blinking reduction mechanism. The nature and thickness of the shell induce a significant increase of the Auger lifetime, leading to a suppression of the dark state. Finally, CdSe/CdS/ZnS nanocrystals are used to develop fluorescent and transparent composite materials (polymer or sol-gel) exhibiting a high refractive index.Nous avons développé des protocoles de synthèse de nanocristaux semiconducteurs à structure cœur/coque CdSe/CdS et CdSe/CdS/ZnS. La présence d'une coque parfaitement cristalline améliore les propriétés de fluorescence des nanocristaux ainsi que leur résistance aux modifications de l'environnement. Nous montrons qu'il est possible de contrôler la structure cristalline de ces objets lors de la synthèse en choisissant les ligands de surface utilisés. Nous montrons de plus que le clignotement de la fluorescence peut être fortement réduit, voire supprimé en synthétisant des nanocristaux cœur/coque CdSe/CdS à coque de CdS parfaitement cristalline et suffisamment épaisse. Ces objets sont étudiés en particule unique. Les mesures de fluorescence et de temps de vie effectuées permettent d'identifier le mécanisme de réduction du clignotement : l'épaisseur et la nature de la coque induit une augmentation significative du temps de recombinaison par effet Auger, ce qui supprime l'état noir. Enfin, les nanocristaux CdSe/CdS/ZnS sont utilisés afin de créer des composites (polymère ou sol-gel) fluorescents, transparents et d'indice élevé

Impact of the steric hindrance of thiol ligands on the optical properties of 2D CdSe semi-conductors

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