Effect of CO2, H2O and SO2 in the ceria-catalyzed combustion of soot under simulated diesel exhaust conditions

The effect of CO2, H2O and SO2 in the Ce0.73Zr0.27O2 and Ce0.64Zr0.27Nd0.09O2 catalyzed combustion of soot with NOx + O2 has been studied. Combustion experiments performed in a fix-bed reactor with soot-catalyst mixtures prepared in loose contact mode showed that CO2, H2O and SO2 lower the activity of both catalysts, and the inhibiting effect follows the trend SO2 > H2O > CO2. Regardless the gas mixture composition, the catalytic activity for soot combustion of Ce0.64Zr0.27Nd0.09O2 is equal or higher to that of Ce0.73Zr0.27O2 because Nd3+ doping seems to promote the participation of the active oxygen mechanism together with the NO2-assisted mechanism in the catalytic combustion of soot. The maximum soot combustion rate achieved during a Ce0.64Zr0.27Nd0.09O2-catalyzed reaction in NOx/O2/CO2/H2O/N2 is about three times higher than that of the uncatalyzed combustion, and this catalyst also improves the CO2 selectivity. In situ DRIFTS experiments showed that CO2, H2O and SO2 compete with NOx for the adsorption sites on the catalysts’ surface. CO2 partially impedes the catalytic oxidation of NO to NO2, affecting much more to the Nd3+-containing catalyst; however, the contribution of the active oxygen mechanism seems to remain relevant in this case. H2O also hinders the catalytic oxidation of NO to NO2 on both catalysts, and therefore the catalytic combustion of soot, because delays the formation of nitrogen reaction intermediates on the catalysts’ surface and favors the formation of more stable nitrogen surface species than in a H2O-free gas stream. For both catalysts, SO2 chemisorption (with sulfate formation) is even able to remove nitrogen surface groups previously formed by NOx chemisorption, which significantly inhibits the catalytic oxidation of NO to NO2 and the catalytic combustion of soot.Financial support of Generalitat Valenciana (Project Prometeo 2009/047), the Spanish Ministry of Economy and Competitiveness (Project CTQ2012-30703), and the UE (FEDER funding)

Diesel soot combustion catalysts: review of active phases

The most relevant information about the different active phases that have been studied for the catalytic combustion of soot is reviewed and discussed in this article. Many catalysts have been reported to accelerate soot combustion, including formulations with noble metals, alkaline metals and alkaline earth metals, transition metals that can accomplish redox cycles (V, Mn, Co, Cu, Fe, etc.), and internal transition metals. Platinum catalysts are among those of most interest for practical applications, and an important feature of these catalysts is that sulphur-resistant platinum formulations have been prepared. Some metal oxide-based catalysts also appear to be promising candidates for soot combustion in practical applications, including ceria-based formulations and mixed oxides with perovskite and spinel structures. Some of these metal oxide catalysts produce highly reactive active oxygen species that promote efficient soot combustion. Thermal stability is an important requirement for a soot combustion catalyst, which precludes the practical utilisation of several potential catalysts such as most alkaline metal catalysts, molten salts, and metal chlorides. Some noble metal catalysts are also unstable due to the formation of volatile oxides (ruthenium, iridium, and osmium).The authors are grateful for the financial support received from Generalitat Valenciana (Project Prometeo 2009/047), the Spanish Ministry of Economy and Competitiveness (Project no. CTQ2012-30703), and the EU (FEDER)

Simultaneous catalytic oxidation of carbon monoxide, hydrocarbons and soot with Ce–Zr–Nd mixed oxides in simulated diesel exhaust conditions

Ce0.73−xZr0.27NdxO2 mixed oxides (x ≤ 0.3) were prepared, characterized by XRD, Raman spectroscopy, N2 adsorption isotherms and H2-TPR, and tested for simultaneous CO, propylene, benzene and soot oxidation in a gas mixture containing O2, NOx, H2O, CO2, CO, propylene (model aliphatic hydrocarbon) and benzene (model aromatic hydrocarbon) that simulates a diesel exhaust. Ce–Zr mixed oxide doping with a low atomic fraction of neodymium (0.01 ≤ x ≤ 0.09) promotes the creation of oxygen vacancies, has a minor effect in the BET specific surface areas of the oxides, increases the surface ceria reducibility and has a positive effect in the catalytic activity. On the contrary, higher neodymium atomic fractions (x = 0.2 and 0.3) promote sintering, with a drastic decrease of the BET specific surface area, surface reducibility and catalytic activity. The Ce0.73−xZr0.27NdxO2 catalysts with x ≤ 0.09 are able to accelerate simultaneously soot, propylene and benzene combustion, and as a general trend, the catalytic behavior of Ce0.73Zr0.27O2 is improved by low atomic fraction neodymium doping (0.01 ≤ x ≤ 0.09). These Ce0.73−xZr0.27NdxO2 mixed oxides with 0.01 ≤ x ≤ 0.09 are also able to accelerate CO oxidation in a certain extent, but there is a net production of CO during soot combustion because the oxidation capacity of these oxides is not high enough to oxidize all CO released as soot combustion product.The authors thank the financial support of CNPq – National Counsel of Technological and Scientific Development (Brazil), of the Spanish Ministry of Economy and Competitiveness (ProjectCTQ2012-30703) and of the UE (FEDER funding)

Ecological wood anatomy of Allenrolfea vaginata (Griseb.) Kuntze (Chenopodiaceae)in saline environments in Santiago del Estero

El objetivo de este estudio fue analizar la variabilidad en las características anatómicas de la madera de Allenrolfea vaginata asociada a tipos de vegetación de sitios con diferentes condiciones de salinidad. Colectamos muestras de madera de 15 individuos provenientes de tres sitios: I) vegetación halófita y suelo Haplic Epi Hypersalic Fluvisol (Endohyposodic, Siltic) sobre un bajo salitroso, II) vegetación xerófila arbustiva y suelo Haplic Endo Hypersalic Fluvisol (Siltic) sobre una paleollanura, y III) vegetación xerófita arbórea y suelo Haplic Endo Hypersalic Solonchak (Endohyposodic, Siltic) sobre una dorsal. Comparamos el diámetro tangencial de lumen de vaso, longitud de elemento de vaso, frecuencia de poros, altura de radio, diámetro y longitud de fibrotraqueida. Además, en cada sitio tomamos muestras del suelo para su caracterización. La estructura anatómica del xilema presenta rasgos xeromórficos que permiten tolerar la escasa disponibilidad de agua, acentuada por la salinidad elevada del suelo. Las variables que variaron significativamente entre sitios fueron el diámetro tangencial del lumen y la longitud de elemento de vaso, el diámetro de fibrotraqueida y la altura de radio. Las principales variables anatómicas de conducción, diámetro y longitud de elemento de vasos, contribuyeron fuertemente a la explicación de la variabilidad total entre sitios; son las variables de mayor significado ecológico. De esta manera, los individuos estudiados presentaron diferencias en la capacidad de conducción y respondieron a la variabilidad en la disponibilidad de agua del suelo entre los sitios, dada por la conductividad eléctrica y la profundidad del horizonte hipersalino, y expresada en los distintos tipos de vegetación. Los vasos más pequeños y cortos que presentaron los individuos de la vegetación halófita con mayor conductividad eléctrica y menor disponibilidad de agua del suelo, confieren mayor seguridad en la conducción de agua que los vasos más largos y grades encontrados en los individuos de la vegetación xerófita arbustiva, con menor conductividad eléctrica que en el sitio anterior. Estos resultados contribuyen al conocimiento de los mecanismos de la estructura anatómica de la madera de una halófita del Chaco Semiárido, que aseguran su supervivencia en diferentes condiciones de salinidad del suelo.This paper aimed to analyze the variability of wood anatomical features of Allenrolfea vaginata (Griseb.) Kuntze (Chenopodiaceae) under different salinity conditions in three vegetation types. Wood samples from 15 individuals in total were collected from three different sites, namely halophyte vegetation and Haplic Epi Hypersalic Fluvisol (Endohyposodic, Siltic) soil over a low brine (site I), xerophytic shrub vegetation and Haplic Endo Hypersalic Fluvisol (Siltic) soil over a paleoplain (site II), and tree xerophyte vegetation and Haplic Endo Hypersalic Solonchak (Endohyposodic, Siltic) soil over a dorsal (site III). The quantitative parameters compared among individuals were: vessel diameter, vessel element length, and vessel frequency, ray height, fiber-tracheid diameter and length. Soil samples were taken from each site for their characterization. Wood anatomy of A. vaginata shows xeromorphic features that allow for its adaptation to water stress which is worsened because of the high soil salinity. The variables with significative differences were: diameter and length of vessel element, fiber-tracheid diameter, and ray height. The main anatomical variables of conduction (i.e., vessel elements diameter and length) help more in explaining the total variability among sites being those with major ecological significance. Thus the individuals under study showed differences in their conducting capacity as a response to the variability in soil water availability of the sites given by the electric conductivity and the hypersaline horizon depth realized in the different types of vegetation. The smaller and shorter vessels of the halophyte vegetation with higher soil electric conductivity and less soil water availability provide higher security for water conduction than those bigger and longer of the xerophytic shrub vegetation with lower electric conductivity. This eco-anatomical study allowed for the completion of an exploratory analysis on the behavior of a set of quantitative anatomical variables and contributes to the understanding of the wood anatomical-structural mechanisms of a halophyte from the Semiarid Chaco assuring its survival under different soil salinity conditions

Deactivation and regeneration of solid acid and base catalyst bodies used in cascade for bio-oil synthesis and upgrading

The modes of deactivation -and the extent to which their properties can be restored- of two catalyst bodies used in cascade for bio-oil synthesis have been studied. These catalysts include a solid acid granulate (namely ZrO2/desilicated zeolite ZSM-5/attapulgite clay) employed in ex-situ catalytic fast pyrolysis of biomass, and a base extrudate (K-exchanged zeolite USY/attapulgite clay) for the subsequent bio-oil upgrading. Post-mortem analyses of both catalyst bodies with Raman spectroscopy and confocal fluorescence microscopy revealed the presence of highly poly-aromatic coke distributed in an egg-shell manner. Deactivation due to coke adsorption onto acid sites affected the zeolite ZSM-5-based catalyst, while for the base catalyst it is structural integrity loss, resulting from KOH-mediated zeolite framework collapse, the main deactivating factor. A hydrothermal regeneration process reversed the detrimental effects of coke in the acid catalyst, largely recovering catalyst acidity (∼80%) and textural properties (∼90%), but worsened the structural damage suffered by the base catalyst

Engineering the acidity and accessibility of the zeolite ZSM-5 for efficient bio-oil upgrading in catalytic pyrolysis of lignocellulose

The properties of the zeolite ZSM-5 have been optimised for the production and deoxygenation of the bio-oil∗ (bio-oil on water-free basis) fraction by lignocellulose catalytic pyrolysis. Two ZSM-5 supports possessing high mesopore/external surface area, and therefore enhanced accessibility, have been employed to promote the conversion of the bulky compounds formed in the primary cracking of lignocellulose. These supports are a nanocrystalline material (n-ZSM-5) and a hierarchical sample (h-ZSM-5) of different Si/Al ratios and acid site concentrations. Acidic features of both zeolites have been modified and adjusted by incorporation of ZrO2, which has a significant effect on the concentration and distribution of both Brønsted and Lewis acid sites. These materials have been tested in the catalytic pyrolysis of acid-washed wheat straw (WS-ac) using a two-step (thermal/catalytic) reaction system at different catalyst/biomass ratios. The results obtained have been assessed in terms of oxygen content, energy yield and composition of the produced bio-oil∗, taking also into account the selectivity towards the different deoxygenation pathways. The ZrO2/n-ZSM-5 sample showed remarkable performance in the biomass catalytic pyrolysis, as a result of the appropriate combination of accessibility and acidic properties. In particular, modification of the zeolitic support acidity by incorporation of highly dispersed ZrO2 effectively decreased the extent of secondary reactions, such as severe cracking and coke formation, as well as promoted the conversion of the oligomers formed initially by lignocellulose pyrolysis, thus sharply decreasing the proportion of the components not detected by GC-MS in the upgraded bio-oil∗

Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells

Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.Instituto de Salud Carlos III PI13/00021Ministerio de Economía y Competitividad BFU2012-32056Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía BIO-0216Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía CTS-6264Consejería de Salud, Junta de Andalucía PI13/ 0002

Multiplex RNA-based detection of clinically relevant MET alterations in advanced non-small cell lung cancer

We studied MET alterations in 474 advanced non-small-cell lung cancer (NSCLC) patients by nCounter, an RNA-based technique. We identified 3% with MET Δex14 mRNA and 3.5% with very-high MET mRNA expression, a surrogate of MET amplification. MET alterations identified by nCounter correlated with clinical benefit from MET inhibitors. Quantitative mRNA-based techniques can improve the selection of patients for MET-targeted therapies. MET inhibitors have shown activity in non-small-cell lung cancer patients (NSCLC) with MET amplification and exon 14 skipping (METΔex14). However, patient stratification is imperfect, and thus, response rates have varied widely. Here, we studied MET alterations in 474 advanced NSCLC patients by nCounter, an RNA-based technique, together with next-generation sequencing (NGS), fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR), exploring correlation with clinical benefit. Of the 474 samples analyzed, 422 (89%) yielded valid results by nCounter, which identified 13 patients (3%) with MET Δex14 and 15 patients (3.5%) with very-high MET mRNA expression. These two subgroups were mutually exclusive, displayed distinct phenotypes and did not generally coexist with other drivers. For MET Δex14, 3/8 (37.5%) samples positive by nCounter tested negative by NGS. Regarding patients with very-high MET mRNA, 92% had MET amplification by FISH and/or NGS. However, FISH failed to identify three patients (30%) with very-high MET RNA expression, among which one received MET tyrosine kinase inhibitor treatment deriving clinical benefit. Our results indicate that quantitative mRNA-based techniques can improve the selection of patients for MET-targeted therapies

COVID-19 outbreaks in a transmission control scenario: challenges posed by social and leisure activities, and for workers in vulnerable conditions, Spain, early summer 2020

Severe acute respiratory syndrome coronavirus 2 community-wide transmission declined in Spain by early May 2020, being replaced by outbreaks and sporadic cases. From mid-June to 2 August, excluding single household outbreaks, 673 outbreaks were notified nationally, 551 active (>6,200 cases) at the time. More than half of these outbreaks and cases coincided with: (i) social (family/friends’ gatherings or leisure venues) and (ii) occupational (mainly involving workers in vulnerable conditions) settings. Control measures were accordingly applied

Cognitive Composites Domain Scores Related to Neuroimaging Biomarkers within Probable-Amnestic Mild Cognitive Impairment-Storage Subtype

The probable-amnestic (Pr-a) mild cognitive impairment (MCI)-storage subtype is a phenotype with 8.5 times more risk of conversion to dementia, mainly Alzheimer's disease (AD), than the possible non-amnestic (Pss-na) MCI. The aim of this study was to find the optimized cognitive composites (CCs) domain scores most related to neuroimaging biomarkers within Pr-aMCI-storage subtype patients. The Fundació ACE (ACE) study with 20 Pr-aMCI-storage subtype subjects (MCI) were analyzed. All subjects underwent a neuropsychological assessment, a structural MRI, FDG-PET, and PIB-PET. The adjusted hippocampal volume (aHV) on MRI, the standard uptake value ratio (SUVR) on FDG-PET and PIB-PET SUVR measures were analyzed. The construction of the CCs domain scores, and the aHV on MRI and FDG-PET SUVR measures, were replicated in the parental AB255 study database (n = 133 MCI). Partial correlations adjusted by age, gender, and education were calculated with the associated p -value among every CC domain score and the neuroimaging biomarkers. The results were replicated in the "MCI due to AD" with memory storage impairments from ADNI. Delayed Recall CC domain score was significantly correlated with PIB-PET SUVR (β= -0.61, p = 0.003) in the ACE study and also with aHV on MRI (β= 0.27, p = 0.01) and FDG-PET SUVR (β= 0.27, p = 0.01) in the AB255 study. After a median survival time of 20.6 months, 85% from the ACE MCI converted to AD. The replication of our results in the ADNI dataset also confirmed our findings. Delayed Recall is the CC domain score best correlated with neuroimaging biomarkers associated with prodromal AD diagnosis