Rationale
Whether asthma constitutes a risk factor for coronavirus disease‐2019 (COVID‐19) is unclear. Here, we aimed to assess whether asthma, the most common chronic disease in children, is ...associated with higher COVID‐19 risk or severity in pediatric populations.
Methods
We performed a systematic literature search in three stages: first, we reviewed PubMed, EMBASE, and CINAHL for systematic reviews of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and COVID‐19 in pediatric populations, and reviewed their primary articles; second, we searched PubMed for studies on COVID‐19 or SARS‐CoV‐2 and asthma/wheeze, and evaluated whether the resulting studies included pediatric populations; third, we repeated the second search in BioRxiv.org and MedRxiv.org to find pre‐prints that may have information on pediatric asthma.
Results
In the first search, eight systematic reviews were found, of which five were done in pediatric populations; none of the 67 primary studies included data on pediatric asthma as a comorbidity for COVID‐19. In the second search, we found 34 results in PubMed, of which five reported asthma in adults, but none included data on children. In the third search, 25 pre‐prints in MedRxiv included data on asthma, but none on children. We found one report by the US Centers for Disease Control and Prevention stating that 40/345 (~11.5%) children with data on chronic conditions had “chronic lung diseases including asthma,” and one from a tertiary hospital in New York that reported asthma in 11/46 (~23.9%) children hospitalized for COVID‐19.
Conclusion
There is scarcely any data on whether childhood asthma (or other pediatric respiratory diseases) constitute risk factors for SARS‐CoV‐2 infection or COVID‐19 severity. Studies are needed that go beyond counting the number of cases in the pediatric age range.
•Phenolic profile and antioxidant properties were evaluated in gluten-free flours.•Violet rice flour possessed the highest phenolic content and antioxidant activity.•Total anthocyanins and ...antioxidant properties were highly correlated.•Multivariate statistics discriminated botanical and food ingredient categories.
The interest in gluten-free (GF) products increases together with the increase in gluten-sensitive people. However, GF foods might have decreased nutritional quality as compared to the gluten containing counterparts. In this work, an investigation of the phenolic and antioxidant profile in 18 GF flours belonging to legumes, cereals and pseudocereals was achieved. Significant differences could be observed across samples. Total phenolic content was highest in violet rice flours, whereas total anthocyanins were highest in violet, nerone, and black rice flours. FRAP and ORAC antioxidant activities were correlated to phenolic contents and found to be higher in violet rice flours. Metabolomics highlighted a wide diversity in phenolics, with flavonoids (197 compounds ascribable to anthocyanins, flavones, flavanones, isoflavonoids, flavonols, and flavanols), phenolic acids (74 compounds belonging to hydroxycinnamics, hydroxybenzoics, and hydroxyphenylacetics), and tyrosol derivatives the most represented. Finally, OPLS-DA multivariate statistics outlined flavonoids, furofurans and phenolic acids as the most discriminant phenolics.
Model metal/ceria and ceria/metal catalysts have been shown to be excellent systems for studying fundamental phenomena linked to the operation of technical catalysts. In the last fifteen years, many ...combinations of well-defined systems involving different kinds of metals and ceria have been prepared and characterized using the modern techniques of surface science. So far most of the catalytic studies have been centered on a few reactions: CO oxidation, the hydrogenation of CO
2
, and the production of hydrogen through the water-gas shift reaction and the reforming of methane or alcohols. Using model catalysts it has been possible to examine in detail correlations between the structural, electronic and catalytic properties of ceria-metal interfaces.
In situ
techniques (X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, infrared spectroscopy, scanning tunneling microscopy) have been combined to study the morphological changes under reaction conditions and investigate the evolution of active phases involved in the cleavage of C-O, C-H and C-C bonds. Several studies with model ceria catalysts have shown the importance of strong metal-support interactions. In general, a substantial body of knowledge has been acquired and concepts have been developed for a more rational approach to the design of novel technical catalysts containing ceria.
Model metal/ceria and ceria/metal catalysts have shown to be excellent systems for studying fundamental phenomena linked to the operation of technical catalysts.
The transformation of methane into methanol or higher alcohols at moderate temperature and pressure conditions is of great environmental interest and remains a challenge despite many efforts. ...Extended surfaces of metallic nickel are inactive for a direct CH4 → CH3OH conversion. This experimental and computational study provides clear evidence that low Ni loadings on a CeO2(111) support can perform a direct catalytic cycle for the generation of methanol at low temperature using oxygen and water as reactants, with a higher selectivity than ever reported for ceria-based catalysts. On the basis of ambient pressure X-ray photoemission spectroscopy and density functional theory calculations, we demonstrate that water plays a crucial role in blocking catalyst sites where methyl species could fully decompose, an essential factor for diminishing the production of CO and CO2, and in generating sites on which methoxy species and ultimately methanol can form. In addition to water-site blocking, one needs the effects of metal–support interactions to bind and activate methane and water. These findings should be considered when designing metal/oxide catalysts for converting methane to value-added chemicals and fuels.
The transformation of CO2 into alcohols or other hydrocarbon compounds is challenging because of the difficulties associated with the chemical activation of CO2 by heterogeneous catalysts. Pure ...metals and bimetallic systems used for this task usually have low catalytic activity. Here we present experimental and theoretical evidence for a completely different type of site for CO2 activation: a copper-ceria interface that is highly efficient for the synthesis of methanol. The combination of metal and oxide sites in the copper-ceria interface affords complementary chemical properties that lead to special reaction pathways for the CO2→CH3OH conversion.
The active sites over commercial copper/zinc oxide/aluminum oxide (Cu/ZnO/Al₂O₃) catalysts for carbon dioxide (CO₂) hydrogenation to methanol, the Zn-Cu bimetallic sites or ZnO-Cu interfacial sites, ...have recently been the subject of intense debate. We report a direct comparison between the activity of ZnCu and ZnO/Cu model catalysts for methanol synthesis. By combining x-ray photoemission spectroscopy, density functional theory, and kinetic Monte Carlo simulations, we can identify and characterize the reactivity of each catalyst. Both experimental and theoretical results agree that ZnCu undergoes surface oxidation under the reaction conditions so that surface Zn transforms into ZnO and allows ZnCu to reach the activity of ZnO/Cu with the same Zn coverage. Our results highlight a synergy of Cu and ZnO at the interface that facilitates methanol synthesis via formate intermediates.
The hidden world of amyloid biology has suddenly snapped into atomic-level focus, revealing over 80 amyloid protein fibrils, both pathogenic and functional. Unlike globular proteins, amyloid proteins ...flatten and stack into unbranched fibrils. Stranger still, a single protein sequence can adopt wildly different two-dimensional conformations, yielding distinct fibril polymorphs. Thus, an amyloid protein may define distinct diseases depending on its conformation. At the heart of this conformational variability lies structural frustrations. In functional amyloids, evolution tunes frustration levels to achieve either stability or sensitivity according to the fibril’s biological function, accounting for the vast versatility of the amyloid fibril scaffold.
A wealth of recent amyloid structures begins to illuminate these puzzling protein conformations, shedding light on how and why different conformations contribute to cellular function or disease.
The water–gas shift (WGS, CO
+
H
2O
→
H
2
+
CO
2) reaction was studied on a series of gold/oxide catalysts. The results of
in situ measurements with X-ray absorption spectroscopy indicate that the ...active phase of Au-ceria and Au-titania catalysts under the reaction conditions of the water–gas shift consists of metallic nanoparticles of gold on a partially reduced oxide support. In spite of the lack of catalytic activity of Au (1
1
1) and other gold surfaces for the water–gas shift process, gold nanoparticles dispersed on oxide surfaces are excellent catalysts for this reaction. Results of density-functional calculations point to a very high barrier for the dissociation of H
2O on Au (1
1
1) or isolated Au nanoparticles, which leads to negligible activity for the WGS process. In the gold-oxide systems, one has a bifunctional catalyst: the adsorption and dissociation of water takes place on the oxide, CO adsorbs on the gold nanoparticles, and all subsequent reaction steps occur at oxide–metal interfaces. The nature of the support plays a key role in the activation of the gold nanoparticles. Although zinc oxide is frequently used in industrial WGS catalysts, the Au/ZnO
(
0
0
0
1
¯
)
system displays low WGS activity when compared to Au/CeO
2 (1
1
1), Au/TiO
2 (1
1
0) or Au/CeO
x
/TiO
2 (1
1
0). The ceria and titania supports contain a substantial number of metal cations that are not fully oxidized under WGS reaction conditions and may participate directly in the dissociation of water and other important steps of the catalytic process. The results for Au/CeO
x
/TiO
2 (1
1
0) illustrate the tremendous impact that an optimization of the chemical properties of gold and the oxide phase can have on the activity of a WGS catalyst.
The Mad1-Mad2 heterodimer is the catalytic hub of the spindle assembly checkpoint (SAC), which controls M phase progression through a multi-subunit anaphase inhibitor, the mitotic checkpoint complex ...(MCC) 1, 2. During interphase, Mad1-Mad2 generates MCC at nuclear pores 3. After nuclear envelope breakdown (NEBD), kinetochore-associated Mad1-Mad2 catalyzes MCC assembly until all chromosomes achieve bipolar attachment 1, 2. Mad1-Mad2 and other factors are also incorporated into the fibrous corona, a phospho-dependent expansion of the outer kinetochore that precedes microtubule attachment 4–6. The factor(s) involved in targeting Mad1-Mad2 to kinetochores in higher eukaryotes remain controversial 7–12, and the specific phosphorylation event(s) that trigger corona formation remain elusive 5, 13. We used genome editing to eliminate Bub1, KNL1, and the Rod-Zw10-Zwilch (RZZ) complex in human cells. We show that RZZ’s sole role in SAC activation is to tether Mad1-Mad2 to kinetochores. Separately, Mps1 kinase triggers fibrous corona formation by phosphorylating two N-terminal sites on Rod. In contrast, Bub1 and KNL1 activate kinetochore-bound Mad1-Mad2 to produce a “wait anaphase” signal but are not required for corona formation. We also show that clonal lines isolated after BUB1 disruption recover Bub1 expression and SAC function through nonsense-associated alternative splicing (NAS). Our study reveals a fundamental division of labor in the mammalian SAC and highlights a transcriptional response to nonsense mutations that can reduce or eliminate penetrance in genome editing experiments.
•RZZ mediates a temporal switch in how Mad1-Mad2 is recruited to kinetochores•Mps1 phosphorylates Rod’s N terminus to trigger fibrous corona formation•Mad1-Mad2 requires a non-receptor activity of Bub1 to inhibit anaphase•Nonsense-associated alternative splicing can circumvent BUB1 disruption
Rodriguez-Rodriguez et al. identify distinct roles for Bub1, KNL1, and RZZ in SAC signaling and fibrous corona formation. They also show that BUB1-disrupted clones re-express Bub1 and regain SAC function via nonsense-associated alternative splicing, an often-overlooked transcriptional response that can limit penetrance in genome editing experiments
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