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2.
Viruses ; 16(3)2024 03 11.
Article de Anglais | MEDLINE | ID: mdl-38543794

RÉSUMÉ

During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) were implemented in order to control the transmission of SARS-CoV-2, potentially affecting the prevalence of respiratory syncytial virus (RSV). This review evaluated the impact of NPIs on RSV-related hospitalizations in children during the lockdown (2020-2021) compared to the pre-pandemic (2015-2020) and post-lockdown (2021-2022) periods. In this systematic review and meta-analysis, we searched through PubMed, Scopus, and Web of Science for studies published in English between 1 January 2015 and 31 December 2022. Additionally, we conducted hand searches of other records published between 1 January 2023 and 22 January 2024. Our target population was hospitalized children aged 0-18 years with RSV-related lower respiratory tract infections confirmed through immunofluorescence, antigen testing, or molecular assays. We focused on peer-reviewed observational studies, analyzing the primary outcome of pooled RSV prevalence. A generalized linear mixed model with a random-effects model was utilized to pool each RSV prevalence. Heterogeneity was assessed using Cochran's Q and I2 statistics, while publication bias was evaluated through funnel plots and Egger's tests. We identified and analyzed 5815 publications and included 112 studies with 308,985 participants. Notably, RSV prevalence was significantly lower during the lockdown period (5.03% [95% CI: 2.67; 9.28]) than during the pre-pandemic period (25.60% [95% CI: 22.57; 28.88], p < 0.0001). However, RSV prevalence increased notably in the post-lockdown period after the relaxation of COVID-19 prevention measures (42.02% [95% CI: 31.49; 53.33] vs. 5.03% [95% CI: 2.67; 9.28], p < 0.0001). Most pooled effect estimates exhibited significant heterogeneity (I2: 91.2% to 99.3%). Our findings emphasize the effectiveness of NPIs in reducing RSV transmission. NPIs should be considered significant public health measures to address RSV outbreaks.


Sujet(s)
COVID-19 , Infections à virus respiratoire syncytial , Infections de l'appareil respiratoire , Enfant , Humains , Enfant hospitalisé , Contrôle des maladies transmissibles , COVID-19/épidémiologie , COVID-19/prévention et contrôle , Pandémies , Prévalence , Infections à virus respiratoire syncytial/épidémiologie , Infections à virus respiratoire syncytial/prévention et contrôle , Infections de l'appareil respiratoire/épidémiologie , Infections de l'appareil respiratoire/prévention et contrôle , Infections de l'appareil respiratoire/virologie , Nouveau-né , Nourrisson , Enfant d'âge préscolaire , Adolescent
3.
Nutrients ; 16(3)2024 Jan 24.
Article de Anglais | MEDLINE | ID: mdl-38337625

RÉSUMÉ

Asthma is one of the most common chronic non-communicable diseases worldwide, characterized by variable airflow limitation secondary to airway narrowing, airway wall thickening, and increased mucus resulting from chronic inflammation and airway remodeling. Current epidemiological studies reported that hypovitaminosis D is frequent in patients with asthma and is associated with worsening the disease and that supplementation with vitamin D3 improves asthma symptoms. However, despite several advances in the field, the molecular mechanisms of asthma have yet to be comprehensively understood. MicroRNAs play an important role in controlling several biological processes and their deregulation is implicated in diverse diseases, including asthma. Evidence supports that the dysregulation of miR-21, miR-27b, miR-145, miR-146a, and miR-155 leads to disbalance of Th1/Th2 cells, inflammation, and airway remodeling, resulting in exacerbation of asthma. This review addresses how these molecular mechanisms explain the development of asthma and its exacerbation and how vitamin D3 may modulate these microRNAs to improve asthma symptoms.


Sujet(s)
Asthme , microARN , Humains , Cholécalciférol/pharmacologie , Cholécalciférol/usage thérapeutique , microARN/génétique , Remodelage des voies aériennes , Asthme/traitement médicamenteux , Asthme/génétique , Asthme/complications , Poumon , Inflammation/complications , Compléments alimentaires
4.
Chempluschem ; 88(11): e202300401, 2023 11.
Article de Anglais | MEDLINE | ID: mdl-37827994

RÉSUMÉ

The conversion of residual biomass from fruit seeds into biochar can be achieved using MgCl2 as an activating agent and calcining at 700 °C. The resulting MgO-biochars were employed in the aldol condensation reaction between furfural and acetone. This reaction is essential as the first step in the obtention of biofuels derived from biomass. The biochars were characterized through various physicochemical techniques, revealing that the presence of MgO nanoparticles deposited on the carbon surface modifies the structural and acidic-basic properties of the carbonaceous materials with a graphitic structure. The biochar with a surface content of MgO of 0.34 % w/w enables the achievement of 100 % of selectivity towards 4-(2-furanyl)-3-buten-2-one (I) with quantitative conversions under optimized conditions. This property highlights the potential of using this type of biochar, commonly used for CO2 capture, as a versatile acidic-basic catalyst, thereby introducing a novel approach to sustainable chemistry.


Sujet(s)
Annona , Biocarburants , Oxyde de magnésium/composition chimique , Graines
5.
Chempluschem ; 88(8): e202300265, 2023 Aug.
Article de Anglais | MEDLINE | ID: mdl-37499219

RÉSUMÉ

The reaction to obtain furan alcohols is one of the most important in the upgrading of furan derivates. An attractive route is the transfer hydrogenation of furfural using acidic-basic catalysts. In this work, mixed oxides derived from ternary hydrotalcites were employed to obtain furfuryl alcohol from furfural assisted by microwave irradiation. These materials were characterized via X-ray diffraction (XRD), N2 adsorption-desorption isotherms, Fourier-transform infrared (FTIR) and the CO2 temperature-programmed desorption (CO2 -TPD) analyses. The lamellar structure of hydrotalcite-type materials collapses during the calcination process, resulting in the loss of carbonate anions and hydroxyl groups, present in the interlayer space. This leads to the formation of mixed oxides that exhibit larger surface areas. Furthermore, these changes alter the basic nature of these materials, giving rise to the formation of strong basic sites. The reaction was studied using containing Co2+ and Ni2+ in their structure and was then optimized using distinct primary and secondary alcohols as hydrogen donor sources, as well as distinct temperatures and initial concentrations of furfural. The yields to furfuryl alcohol are strongly dependent on the type of Me2+ in layered oxides mainly due to higher basicity and to the donor employed in the reaction. The mixed oxide containing Co2+ showed complete conversion of furfural and higher yields to furfuryl alcohol (>95 %) at short times of reaction (<1 h).

6.
Int J Mol Sci ; 24(7)2023 Mar 30.
Article de Anglais | MEDLINE | ID: mdl-37047453

RÉSUMÉ

Asthma is a heterogeneous entity encompassing distinct endotypes and varying phenotypes, characterized by common clinical manifestations, such as shortness of breath, wheezing, and variable airflow obstruction. Two major asthma endotypes based on molecular patterns are described: type 2 endotype (allergic-asthma) and T2 low endotype (obesity-related asthma). Long noncoding RNAs (lncRNAs) are transcripts of more than 200 nucleotides in length, currently involved in many diverse biological functions, such as chromatin remodeling, gene transcription, protein transport, and microRNA processing. Despite the efforts to accurately classify and discriminate all the asthma endotypes and phenotypes, if long noncoding RNAs could play a role as biomarkers in allergic asthmatic and adolescent obesity-related asthma, adolescents remain unknown. To compare expression levels of lncRNAs: HOTAIRM1, OIP5-AS1, MZF1-AS1, and GAS5 from whole blood of Healthy Adolescents (HA), Obese adolescents (O), allergic asthmatic adolescents (AA) and Obesity-related asthma adolescents (OA). We measured and compared expression levels from the whole blood of the groups mentioned above through RT-q-PCR. We found differentially expressed levels of these lncRNAs between the groups of interest. In addition, we found a discriminative value of previously mentioned lncRNAs between studied groups. Finally, we generated an interaction network through bioinformatics. Expression levels of OIP5-AS1, MZF1-AS1, HOTAIRM1, and GAS5 in whole blood from the healthy adolescent population, obese adolescents, allergic asthma adolescents, and obesity-related asthma adolescents are differently expressed. Moreover, these lncRNAs could act as molecular biomarkers that help to discriminate between all studied groups, probably through molecular mechanisms with several genes and miRNAs implicated.


Sujet(s)
Asthme , microARN , Obésité pédiatrique , ARN long non codant , Adolescent , Humains , ARN long non codant/génétique , ARN long non codant/métabolisme , Obésité pédiatrique/complications , Obésité pédiatrique/génétique , microARN/génétique , microARN/métabolisme , Asthme/génétique , Marqueurs biologiques , Prolifération cellulaire/génétique , Facteurs de transcription Krüppel-like
7.
Chemosphere ; 315: 137606, 2023 Feb.
Article de Anglais | MEDLINE | ID: mdl-36574787

RÉSUMÉ

This work aimed to study NiO/F-TiO2 composites in the photocatalytic degradation of 4-chlorophenol. F-TiO2 support was prepared by in-situ fluorination of TiO2 using the sol-gel method. The heterostructured materials were prepared by wet impregnation method, varying NiO content (0.5, 1.0, and 2.0% wt). The solids were characterized by X-ray fluorescence, X-ray diffraction, nitrogen physisorption, diffuse reflectance UV-Vis spectrophotometry, infrared spectroscopy, and X-ray photoelectron spectroscopy. The characterization studies showed that the coupling of TiO2 with fluoride ions promoted the generation of ≡Ti-F surface species that could be responsible for the decrease in the recombination frequency of charge carriers and the increased photoactivity. In addition, it was found that the coupling of NiO/F-TiO2 semiconductors improved the photocatalytic properties of the fluorinated support, obtaining higher percentages of degradation and mineralization of the phenolic contaminant. These results are possibly a consequence of factors such as the formation of larger crystallites, lower band gap energies, and the generation of p-n type interfacial heterojunctions that potentiate the proper separation of electron-hole pairs. An effect of NiO content on photoactivity was observed, being a percentage of 1.0% wt the optimum in this photocatalytic treatment.


Sujet(s)
Lumière , Nanocomposites , Photolyse , Titane/composition chimique , Nanocomposites/composition chimique , Catalyse
8.
Nutrients ; 14(19)2022 Oct 01.
Article de Anglais | MEDLINE | ID: mdl-36235741

RÉSUMÉ

In the modern diet, excessive fructose intake (>50 g/day) had been driven by the increase, in recent decades, of the consumption of sugar-sweetened beverages. This phenomenon has dramatically increased within the Caribbean and Latin American regions. Epidemiological studies show that chronic high intake of fructose related to sugar-sweetened beverages increases the risk of developing several non-communicable diseases, such as chronic obstructive pulmonary disease and asthma, and may also contribute to the exacerbation of lung diseases, such as COVID-19. Evidence supports several mechanisms­such as dysregulation of the renin−angiotensin system, increased uric acid production, induction of aldose reductase activity, production of advanced glycation end-products, and activation of the mTORC1 pathway­that can be implicated in lung damage. This review addresses how these pathophysiologic and molecular mechanisms may explain the lung damage resulting from high intake of fructose.


Sujet(s)
Fructose , Maladies pulmonaires , Aldose reductase , Fructose/effets indésirables , Humains , Maladies pulmonaires/épidémiologie , Maladies pulmonaires/physiopathologie , Complexe-1 cible mécanistique de la rapamycine , Édulcorants/effets indésirables , Acide urique
10.
Heliyon ; 8(12): e12316, 2022 Dec.
Article de Anglais | MEDLINE | ID: mdl-36590520

RÉSUMÉ

A higher Th17-immune response characterises obesity and obesity-related asthma phenotype. Nevertheless, obesity-related asthma has a more significant Th17-immune response than obesity alone. Retinoid-related orphan receptor C (RORC) is the essential transcription factor for Th17 polarisation. Previous studies have found that adolescents with obesity-related asthma presented upregulation of RORC, IL17A, and TNFA. However, the mechanisms that cause these higher mRNA expression levels in this asthmatic phenotype are poorly understood. Methylation directly regulates gene expression by adding a methyl group to carbon 5 of dinucleotide CpG cytosine. Thus, we evaluated the relationship between RORC, IL17A, and TNFA methylation status and mRNA expression levels to investigate a possible epigenetic regulation. A total of 102 adolescents (11-18 years) were studied in the following four groups: 1) healthy participants (HP), 2) allergic asthmatic participants (AAP), 3) obese participants without asthma (OP), and 4) non-allergic obesity-related asthma participants (OAP). Real-time qPCR assessed the methylation status and gene expression levels in peripheral blood leukocytes. Remarkably, the OAP and AAP groups have lower promoter methylation patterns of RORC, IL17A, and TNFA than the HP group. Notably, the OAP group presents lower RORC promoter methylation status than the OP group. Interestingly, RORC promoter methylation status was moderately negatively associated with gene expression of RORC (r s = -0.39, p < 0.001) and IL17A (r s = -0.37, p < 0.01), respectively. Similarly, the promoter methylation pattern of IL17A was moderately negatively correlated with IL17A gene expression (r s = -0.3, p < 0.01). There is also a moderate inverse relationship between TNFA promoter methylation status and TNFA gene expression (r s = -0.3, p < 0.01). The present study suggests an association between lower RORC, IL17A, and TNFA gene promoter methylation status with obesity-related asthma and allergic asthma. RORC, IL17A, and TNFA gene promoter methylation patterns are moderately inversely correlated with their respective mRNA expression levels. Therefore, DNA methylation may regulate RORC, IL17A, and TNF gene expression in both asthmatic phenotypes.

11.
Chemosphere ; 288(Pt 2): 132506, 2022 Feb.
Article de Anglais | MEDLINE | ID: mdl-34656628

RÉSUMÉ

The interest in the removal of emerging contaminants has increased in the last decade. Photocatalytic degradation using p-n heterojunctions could effectively provide the degradation of these type of substances that are persistent in the environment. In this work, the synthesis, characterization, and photocatalytic evaluation of TiO2-F as well as CuO/TiO2-F and NiO/TiO2-F composite materials were studied in the photo-assisted degradation of caffeine using UV radiation. The fluorination of titanium dioxide induced changes in some physicochemical properties of the materials, which contributed to a decrease in surface area and bandgap energy as well as an increase in crystallite size as compared to pristine TiO2. ≡Ti-F species were evidenced to be formed, which could favor charge separation processes. A highest segregation of CuO species in comparison with NiO on the surface of TiO2-F could be formed, which could increase defect sites and decrease the band gap. The formation of a heterojunction between the semiconductors was evidenced, responsible for the observed improvements in photocatalytic properties of the composite materials. The photocatalytic tests evidenced an important degradation of caffeine; however, mineralization was incomplete. The stability of the composite materials and their potential use in the photocatalytic treatment of caffeine was evaluated by reuse tests.


Sujet(s)
Caféine , Rayons ultraviolets , Cuivre , Titane
12.
Materials (Basel) ; 14(10)2021 May 11.
Article de Anglais | MEDLINE | ID: mdl-34064575

RÉSUMÉ

Whey in large quantities can cause environmental problems when discarded, because it reduces dissolved oxygen and aquatic life. Nonetheless, it could be used as an easily available and economical alternative to reduce culture medium costs in microbially induced calcium carbonate precipitation (MICP). In this work, a native Sporosarcina pasteurii was isolated and then cultured by using different proportions of whey (W) in nutrient broth (NB). The solids were characterized by XRD, FT-IR, TGA, and SEM. The potential applications in bioconsolidation were also studied. Whey concentration was directly related to CaCO3 production. Higher whey concentrations reduced calcium carbonate purity to nearly 80%. All experiments showed calcite and vaterite fractions, where a whey increment in the media increased calcite content and decreased vaterite content, causing a decrease in crystal size. MICP improved compressive strength (CS) in sand and fly ash. The best CS results were obtained by fly ash treated with 25 W-75 NB (37.2 kPa) and sand with 75 W-25 NB (32.1 kPa). Whey changed crystal polymorphism in biogenic CaCO3 production. Material bioconsolidation depends on the CaCO3 polymorph, thus fly ash was effectively bioconsolidated by crystallization of vaterite and sand by crystallization of calcite.

13.
Allergol Immunopathol (Madr) ; 49(3): 21-29, 2021.
Article de Anglais | MEDLINE | ID: mdl-33938185

RÉSUMÉ

BACKGROUND: Non-allergic asthma caused by obesity is a complication of the low-grade chronic inflammation inherent in obesity. Consequently, the serum concentrations of adipokines such as retinol-binding protein 4 (RBP4) and plasminogen activator inhibitor-1 (PAI-1) increase. No gold standard molecule for the prediction of non-allergic asthma among obese patients has been identified. OBJECTIVE: To evaluate RBP4 and PAI-1 as prognostic biomarkers of non-allergic asthma caused by obesity. METHODS: A cross-sectional study between four groups of adolescents: (1) healthy (n = 35), (2) allergic asthma without obesity (n = 28), (3) obesity without asthma (n = 33), and (4) non-allergic asthma with obesity (n = 18). RESULTS: RBP4 was higher in the non-allergic asthma with obesity group than in the obesity without asthma group (39.2 ng/mL [95% confidence interval (CI): 23.8-76.0] vs. 23.5 ng/mL [95% CI: 3.2-33.5], p < 0.01), and PAI-1 was higher in the non-allergic asthma with obesity group than in the obesity without asthma group (21.9 ng/mL [95% CI: 15.7-26.5] vs. 15.9 ng/mL [95% CI: 9.4-18.2], p < 0.05). Receiver operating characteristic (ROC) curve analysis demonstrated that the serum RBP4 cut-off value was >42.78 ng/mL, with an area under the ROC curve (AUC) of 0.741 (95% CI: 0.599-0.853, p = 0.001), considered acceptable. The PAI-1 cut-off value was >12.0 ng/mL, with an AUC of 0.699 (95% CI: 0.554-0.819, p = 0.008), considered fair. CONCLUSIONS: RBP4 may be useful to predict non-allergic asthma among obese adolescents in clinical practice.


Sujet(s)
Asthme/sang , Obésité pédiatrique/complications , Inhibiteur-1 d'activateur du plasminogène/sang , Protéines plasmatiques de liaison au rétinol/analyse , Adolescent , Asthme/étiologie , Marqueurs biologiques/sang , Indice de masse corporelle , Enfant , Intervalles de confiance , Études transversales , Femelle , Humains , Mâle , Obésité pédiatrique/sang , Pronostic , Courbe ROC
15.
Allergol. immunopatol ; 49(3): 21-29, mayo 2021. tab, graf
Article de Anglais | IBECS | ID: ibc-214262

RÉSUMÉ

Background: Non-allergic asthma caused by obesity is a complication of the low-grade chronic inflammation inherent in obesity. Consequently, the serum concentrations of adipokines such as retinol-binding protein 4 (RBP4) and plasminogen activator inhibitor-1 (PAI-1) increase. No gold standard molecule for the prediction of non-allergic asthma among obese patients has been identified. Objective: To evaluate RBP4 and PAI-1 as prognostic biomarkers of non-allergic asthma caused by obesity. Methods: A cross-sectional study between four groups of adolescents: (1) healthy (n = 35), (2) allergic asthma without obesity (n = 28), (3) obesity without asthma (n = 33), and (4) non-allergic asthma with obesity (n = 18). Results: RBP4 was higher in the non-allergic asthma with obesity group than in the obesity without asthma group (39.2 ng/mL [95% confidence interval (CI): 23.8–76.0] vs. 23.5 ng/mL [95% CI: 3.2–33.5], p < 0.01), and PAI-1 was higher in the non-allergic asthma with obesity group than in the obesity without asthma group (21.9 ng/mL [95% CI: 15.7–26.5] vs. 15.9 ng/mL [95% CI: 9.4–18.2], p < 0.05). Receiver operating characteristic (ROC) curve analysis demonstrated that the serum RBP4 cut-off value was >42.78 ng/mL, with an area under the ROC curve (AUC) of 0.741 (95% CI: 0.599–0.853, p = 0.001), considered acceptable. The PAI-1 cut-off value was >12.0 ng/mL, with an AUC of 0.699 (95% CI: 0.554–0.819, p = 0.008), considered fair Conclusions: RBP4 may be useful to predict non-allergic asthma among obese adolescents in clinical practice (AU)


Sujet(s)
Humains , Enfant , Adolescent , Asthme/sang , Obésité pédiatrique/complications , Inhibiteur-1 d'activateur du plasminogène/sang , Protéines de liaison au rétinol/analyse , Asthme/étiologie , Marqueurs biologiques/sang , Indice de masse corporelle , Intervalles de confiance , Études transversales , Pronostic
16.
Nat Commun ; 12(1): 1615, 2021 03 12.
Article de Anglais | MEDLINE | ID: mdl-33712580

RÉSUMÉ

Exceptionally long-lived species, including many bats, rarely show overt signs of aging, making it difficult to determine why species differ in lifespan. Here, we use DNA methylation (DNAm) profiles from 712 known-age bats, representing 26 species, to identify epigenetic changes associated with age and longevity. We demonstrate that DNAm accurately predicts chronological age. Across species, longevity is negatively associated with the rate of DNAm change at age-associated sites. Furthermore, analysis of several bat genomes reveals that hypermethylated age- and longevity-associated sites are disproportionately located in promoter regions of key transcription factors (TF) and enriched for histone and chromatin features associated with transcriptional regulation. Predicted TF binding site motifs and enrichment analyses indicate that age-related methylation change is influenced by developmental processes, while longevity-related DNAm change is associated with innate immunity or tumorigenesis genes, suggesting that bat longevity results from augmented immune response and cancer suppression.


Sujet(s)
Chiroptera/génétique , Méthylation de l'ADN , Longévité/génétique , Vieillissement/génétique , Animaux , Carcinogenèse/génétique , Chromatine , Épigenèse génétique , Techniques génétiques , Histone , Immunité innée/génétique , Phylogenèse
17.
Clin Immunol ; 229: 108715, 2021 08.
Article de Anglais | MEDLINE | ID: mdl-33771687

RÉSUMÉ

Obesity is associated with a unique non-T2 asthma phenotype, characterised by a Th17 immune response. Retinoid-related orphan receptor C (RORC) is the master transcription factor for Th17 polarisation. We investigated the association of TNFA, IL17A, and RORC mRNA expression levels with the non-T2 phenotype. We conducted a cross-sectional study in adolescents, subdivided as follows: healthy (HA), allergic asthma without obesity (AA), obesity without asthma (OB), and non-allergic asthma with obesity (NAO). TNFA, IL17A, and RORC mRNA expression in peripheral blood leukocytes were assessed by RT-PCR. NAO exhibited higher TNFA mRNA expression levels than HA or OB, as well as the highest IL17A and RORC mRNA expression levels among the four groups. The best biomarker for discriminating non-allergic asthma among obese adolescents was RORC mRNA expression levels (area under the curve: 0.95). RORC mRNA expression levels were associated with the non-T2 asthma phenotype, hinting at a therapeutic target in obesity-related asthma.


Sujet(s)
Asthme/complications , Asthme/immunologie , Interleukine-17/génétique , Membre-3 du groupe F de la sous-famille-1 de récepteurs nucléaires/génétique , Obésité/complications , Obésité/immunologie , ARN messager/génétique , Facteur de nécrose tumorale alpha/génétique , Adolescent , Asthme/génétique , Marqueurs biologiques/sang , Enfant , Études transversales , Femelle , Expression des gènes , Humains , Interleukine-17/sang , Leucocytes/immunologie , Mâle , Obésité/génétique , Phénotype , ARN messager/sang , Cellules Th17/immunologie , Facteur de nécrose tumorale alpha/sang
19.
Med Hypotheses ; 144: 109935, 2020 Nov.
Article de Anglais | MEDLINE | ID: mdl-32795834

RÉSUMÉ

Coronavirus disease 2019 (COVID-19) was declared a pandemic and international health emergency by the World Health Organization. Patients with obesity with COVID-19 are 7 times more likely to need invasive mechanical ventilation than are patients without obesity (OR 7.36; 95% CI: 1.63-33.14, p = 0.021). Acute respiratory distress syndrome (ARDS) is one of the main causes of death related to COVID-19 and is triggered by a cytokine storm that damages the respiratory epithelium. Interleukins that cause the chronic low-grade inflammatory state of obesity, such as interleukin (IL)-1ß, IL-6, monocyte chemoattractant peptide (MCP)-1, and, in particular, IL-17A and tumour necrosis factor alpha (TNF-α), also play very important roles in lung damage in ARDS. Therefore, obesity is associated with an immune state favourable to a cytokine storm. Our hypothesis is that serum concentrations of TNF-α and IL-17A are more elevated in patients with obesity and COVID-19, and consequently, they have a greater probability of developing ARDS and death. The immunobiology of IL-17A and TNF-α opens a new fascinating field of research for COVID-19.


Sujet(s)
COVID-19/complications , Interleukine-17/sang , Obésité/complications , 12549/étiologie , Facteur de nécrose tumorale alpha/sang , Marqueurs biologiques/sang , COVID-19/immunologie , COVID-19/mortalité , Syndrome de libération de cytokines/étiologie , Syndrome de libération de cytokines/immunologie , Syndrome de libération de cytokines/mortalité , Humains , Modèles immunologiques , Obésité/immunologie , Pandémies , 12549/immunologie , 12549/mortalité , Muqueuse respiratoire/immunologie , Muqueuse respiratoire/traumatismes , Facteurs de risque
20.
Materials (Basel) ; 13(3)2020 Feb 07.
Article de Anglais | MEDLINE | ID: mdl-32046065

RÉSUMÉ

The search for catalysts with features that can improve coke resistance and decrease byproduct formation is a current goal in H2 production from renewable sources. In this work, the effect of the presence of Ni nanoparticles over Co/La-Ce oxides on the ethanol decomposition reaction was studied. Catalysts were synthetized using as precursor a La0.8Ce0.2NixCo1-xO3 perovskite-type material to ensure a low segregation of phases and a high dispersion of metals. After reduction at 873 K, the perovskite structure was destroyed, and metal Co-Ni particles were supported over a lanthanum-cerium oxide. The materials were characterized by different techniques before and after reaction. Solids exhibited metal particle sizes between 5 and 15 nm demonstrating the advantages of the preparation method to obtain Ni-Co alloys. Although the results of adsorption of ethanol followed by diffuse reflectance infrared fourier transformed spectroscopy (DRIFTS) showed acetate species strongly adsorbed on the catalyst's surface, the material (Ni0.7Co0.3/La0.8Ce0.2) with the lowest particle size was the most stable system leading to the lowest amount of carbon deposits during ethanol decomposition. This catalyst showed the better performance, with a higher ethanol conversion (98.4%) and hydrogen selectivity (75%). All catalysts exhibited carbonaceous deposits, which were an ordered and disordered carbon phase mixture.

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