Abstract
Manganese abundances are sensitive probes of the progenitors of Type Ia supernovae (SNe Ia). In this work, we present a catalog of manganese abundances in dwarf spheroidal satellites of the ...Milky Way, measured using medium-resolution spectroscopy. Using a simple chemical evolution model, we infer the manganese yield of SNe Ia in the Sculptor dwarf spheroidal galaxy (dSph) and compare to theoretical yields. The sub-solar yield from SNe Ia (
at Fe/ H = −1.5 dex, with negligible dependence on metallicity) implies that sub-Chandrasekhar-mass (sub-
M
Ch
) white dwarf progenitors are the dominant channel of SNe Ia at early times in this galaxy, although some fraction (≳20%) of
M
Ch
Type Ia or Type Iax SNe are still needed to produce the observed yield. First-order corrections for deviations from local thermodynamic equilibrium increase the inferred
by as much as ∼0.3 dex. However, our results also suggest that the nucleosynthetic source of SNe Ia may depend on environment. In particular, we find that dSphs with extended star formation histories (Leo I, Fornax dSphs) appear to have higher Mn/Fe at a given metallicity than galaxies with early bursts of star formation (Sculptor dSph), suggesting that
M
Ch
progenitors may become the dominant channel of SNe Ia at later times in a galaxy’s chemical evolution.
Outdoor air pollution and biomass smoke exposure are related to the prevalence of chronic obstructive pulmonary disease (COPD). Since Osorno, Chile, is saturated with fine particulate matter (PM2.5), ...the aim of this work is to determine the prevalence distribution of COPD patients in the Primary Health Care (PHC) system in the city of Osorno, and its relationship with PM2.5. A cross-sectional descriptive study was carried out on COPD patients enrolled in the six PHC centers (PHCCs) of the city to assess the adjusted prevalence (population over 40 years). Gender- and territory-associated odds ratios (ORs) were also determined. In addition, an urban analysis of the distribution of PM2.5 and an exploratory analysis of the spatial behavior of enrolled COPD patients through featured binning were carried out. In 2018, the city of Osorno had 809 enrolled COPD patients in the PHC system (55.1% female), with a 1.3% age-adjusted prevalence (inhabitants over 40 years old), which was 11.7% after underdiagnosis correction. The COPD patients were mainly between 70 and 79 years old (34.3%). The urban area under the administration of the PHCC Rahue Alto (PHCC-RA) had a higher OR (1.98 1.73–2.26) compared to the situation of the city. Also, air pollution (PM2.5) was the highest in the PHCC-RA area, which could account for the observed prevalence. The number of COPD patients in this area is the highest in the commune, which increases the risk of complications derived from the disease and air pollution. Thus, territories with the highest COPD prevalence have the largest OR, which could complicate patients’ condition due to the high levels of outdoor air pollution.
Obesity-related diseases, including type 2 diabetes and cardiovascular disease, have reached epidemic proportions in industrialized nations, and dietary interventions for their prevention are ...therefore important. Resistant starches (RS) improve insulin sensitivity in clinical trials, but the mechanisms underlying this health benefit remain poorly understood. Because RS fermentation by the gut microbiota results in the formation of physiologically active metabolites, we chose to specifically determine the role of the gut microbiota in mediating the metabolic benefits of RS. To achieve this goal, we determined the effects of RS when added to a Western diet on host metabolism in mice with and without a microbiota.
RS feeding of conventionalized mice improved insulin sensitivity and redressed some of the Western diet-induced changes in microbiome composition. However, parallel experiments in germ-free littermates revealed that RS-mediated improvements in insulin levels also occurred in the absence of a microbiota. RS reduced gene expression of adipose tissue macrophage markers and altered cecal concentrations of several bile acids in both germ-free and conventionalized mice; these effects were strongly correlated with the metabolic benefits, providing a potential microbiota-independent mechanism to explain the physiological effects of RS.
This study demonstrated that some metabolic benefits exerted by dietary RS, especially improvements in insulin levels, occur independently of the microbiota and could involve alterations in the bile acid cycle and adipose tissue immune modulation. This work also sets a precedent for future mechanistic studies aimed at establishing the causative role of the gut microbiota in mediating the benefits of bioactive compounds and functional foods.
With the advent of graphene, the most studied of all two-dimensional materials, many inorganic analogues have been synthesized and are being exploited for novel applications. Several approaches have ...been used to obtain large-grain, high-quality materials. Naturally occurring ores, for example, are the best precursors for obtaining highly ordered and large-grain atomic layers by exfoliation. Here, we demonstrate a new two-dimensional material 'hematene' obtained from natural iron ore hematite (α-Fe
O
), which is isolated by means of liquid exfoliation. The two-dimensional morphology of hematene is confirmed by transmission electron microscopy. Magnetic measurements together with density functional theory calculations confirm the ferromagnetic order in hematene while its parent form exhibits antiferromagnetic order. When loaded on titania nanotube arrays, hematene exhibits enhanced visible light photocatalytic activity. Our study indicates that photogenerated electrons can be transferred from hematene to titania despite a band alignment unfavourable for charge transfer.
Background: The transcriptional regulatory network involved in low temperature response leading to acclimation has been established in Arabidopsis. In japonica rice, which can only withstand ...transient exposure to milder cold stress (10°C), an oxidative-mediated network has been proposed to play a key role in configuring early responses and short-term defenses. The components, hierarchical organization and physiological consequences of this network were further dissected by a systems-level approach. Results: Regulatory clusters responding directly to oxidative signals were prominent during the initial 6 to 12 hours at 10°C. Early events mirrored a typical oxidative response based on striking similarities of the transcriptome to disease, elicitor and wounding induced processes. Targets of oxidative-mediated mechanisms are likely regulated by several classes of bZIP factors acting on as1/ocs/TGA-like element enriched clusters, ERF factors acting on GCC-box/JAre-like element enriched clusters and R2R3-MYB factors acting on MYB2-like element enriched clusters. Temporal induction of several H2O2-induced bZIP, ERF and MYB genes coincided with the transient H2O2 spikes within the initial 6 to 12 hours. Oxidative-independent responses involve DREB/CBF, RAP2 and RAV1 factors acting on DRE/CRT/rav1-like enriched clusters and bZIP factors acting on ABRE-like enriched clusters. Oxidative-mediated clusters were activated earlier than ABA-mediated clusters. Conclusion: Genome-wide, physiological and whole-plant level analyses established a holistic view of chilling stress response mechanism of japonica rice. Early response regulatory network triggered by oxidative signals is critical for prolonged survival under sub-optimal temperature. Integration of stress and developmental responses leads to modulated growth and vigor maintenance contributing to a delay of plastic injuries.
► SBA-16 substrate modified with 1wt.% of P is an efficient support for NiMoW HDS catalysts. ► The NiMoW/SBA-16 sulfide catalyst with 1wt.% of P is more active in HDS reaction than the P-free ...counterpart. ► The formation of “onion-type” Mo(W)S2 structure is detrimental for HDS activity.
P-containing SBA-16 mesoporous systems were used as supports of ternary Ni–Mo–W hydrodesulfurization (HDS) catalysts. The samples were characterized by a variety of techniques (N2 adsorption–desorption isotherms, XRD, TPR, TPD-NH3, DRS UV–vis and HRTEM). XRD profiles evidenced the formation of crystalline Mo1-xWxO3 and NiMoO4 phases on the surface of oxide catalyst precursors with high P-loadings (1.0 and 1.6wt.%). The UV–vis DRS measurements showed a substantial decrease of energy band gap after P-loading onto the SBA-16 substrate with respect to P-free sample. The sulfided catalysts were tested in separate HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) reactions performed in a batch reactor at 320°C and H2 pressure of 5.0MPa. For both HDS reactions, the initial catalyst activity displayed a volcano-type curve indicating that catalyst behavior depends strongly on the phosphorous loading being all catalysts more active in the HDS of DBT then in the HDS of 4,6-DMDBT. The NiMoW/SBA-16 catalyst loaded with optimized amount of phosphorous (1.0wt.%) showed superior initial activity than the P-free counterpart. This effect was attributed to the enhancement of active phases dispersion on the support surface, as revealed by HRTEM measurements. It was found that the formation of “onion-type” Mo(W)S2 phases on the catalyst surface was detrimental for the HDS activity. At reaction time of 5h, the most active NiMoW/SBA-16 catalyst loaded with 1.0wt.% of P showed similar activity in both HDS of DBT and 4,6-DMDBT reactions. It was found that HYD route of both reactions was promoted by the support modification with P and due to inhibition of coordinatively unsaturated sites (CUSs) by competitive adsorption of products (mainly H2S).
Bacteroides fragilis is the most frequent species at the human intestinal mucosal surface, it contributes to the maturation of the immune system although is also considered as an opportunistic ...pathogen. Some Bifidobacterium strains produce exopolysaccharides (EPS), complex carbohydrate polymers that promote changes in the metabolism of B. fragilis when this microorganism grows in their presence. To demonstrate that B. fragilis can use EPS from bifidobacteria as fermentable substrates, purified EPS fractions from two strains, Bifidobacterium longum E44 and Bifidobacterium animalis subsp. lactis R1, were added as the sole carbon source in cultures of B. fragilis DSMZ 2151 in a minimal medium. Bacterial counts were determined during incubation and the evolution of organic acids, short chain fatty acids (SCFA) and evolution of EPS fractions was analysed by chromatography.
Growth of B. fragilis at early stages of incubation was slower in EPS than with glucose, microbial levels remaining higher in EPS at prolonged incubation times. A shift in metabolite production by B. fragilis occurred from early to late stages of growth, leading to the increase in the production of propionate and acetate whereas decrease lactate formation. The amount of the two peaks with different molar mass of the EPS E44 clearly decreased along incubation whereas a consumption of the polymer R1 was not so evident.
This report demonstrates that B. fragilis can consume some EPS from bifidobacteria, with a concomitant release of SCFA and organic acids, suggesting a role for these biopolymers in bacteria-bacteria cross-talk within the intestine.
The H.E.S.S. Galactic plane survey Angüner, E. O.; Arakawa, M.; Aubert, P. ...
Astronomy and astrophysics (Berlin),
04/2018, Letnik:
612
Journal Article
Recenzirano
Odprti dostop
We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) γ-rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the ...discovery of 16 new sources of VHE γ-rays. The High Energy Spectroscopic System (H.E.S.S.) Galactic plane survey (HGPS) was a decade-long observation program carried out by the H.E.S.S. I array of Cherenkov telescopes in Namibia from 2004 to 2013. The observations amount to nearly 2700 h of quality-selected data, covering the Galactic plane at longitudes from ℓ = 250° to 65° and latitudes |b|≤ 3°. In addition to the unprecedented spatial coverage, the HGPS also features a relatively high angular resolution (0.08° ≈ 5 arcmin mean point spread function 68% containment radius), sensitivity (≲1.5% Crab flux for point-like sources), and energy range (0.2–100 TeV). We constructed a catalog of VHE γ-ray sources from the HGPS data set with a systematic procedure for both source detection and characterization of morphology and spectrum. We present this likelihood-based method in detail, including the introduction of a model component to account for unresolved, large-scale emission along the Galactic plane. In total, the resulting HGPS catalog contains 78 VHE sources, of which 14 are not reanalyzed here, for example, due to their complex morphology, namely shell-like sources and the Galactic center region. Where possible, we provide a firm identification of the VHE source or plausible associations with sources in other astronomical catalogs. We also studied the characteristics of the VHE sources with source parameter distributions. 16 new sources were previously unknown or unpublished, and we individually discuss their identifications or possible associations. We firmly identified 31 sources as pulsar wind nebulae (PWNe), supernova remnants (SNRs), composite SNRs, or gamma-ray binaries. Among the 47 sources not yet identified, most of them (36) have possible associations with cataloged objects, notably PWNe and energetic pulsars that could power VHE PWNe.
The study of the soil properties and geochemistry of vineyard soils of the Méntrida Protected Designation of Origin (PDO) (central Spain) was performed to better understand the role of soil as a ...terroir component and to contribute to sustainable vineyard management. Soil physico‐chemical characteristics were determined, along with the content of trace elements (by placing emphasis on rare earths) in topsoils and subsoils. The dominant soil types were Inceptisols, Alfisols and Entisols (USDA soil classificacion), i.e., Cambisols, Luvisols and Regosols in the World Reference Base for Soil Resources (WRB) system. They were all deep and well‐structured. Our findings reveal that soil‐available nitrogen (N) ranged from 0.03 to 0.21 (%), with soil‐available phosphorus (P) ranging from 0.20 to 40.50 (mg·kg−1). pH had a mean of 6.33 (range: 4.4–8.7) in the ten observations, and a degree of mesotrophic saturation in bases (V%), except in one that had a 100% value (soils where carbonates were absent, save exceptional cases). A medium to high cation exchange capacity (CEC) was found (range: 9.8–38.3 cmol·kg−1). The mean values of elements' contents were (mg·kg−1): Sc 14.8, V 32.13, Cr 23.09, As 4.01, Ni 8.57, Cu 6.43, Zn 30.13, Rb 143.49, Sr 63.03, Y 15.39, Ba 374,44, La 25.87, Ce 43.77, Pb 22.25, Nd 21.28. They decreased in this order: Ba > Rb > Sr > Ce > V > Zn > La > Cr > Pb > Nd > Y > Sc > Cu > As. The results confirm the importance of soils for the PDO, with an optimum condition to produce grapevine quality laying the foundations to obtain a good wine. Our findings provide insights into the importance of pedological properties for regulating soil nutrient availability across soil types, and support soil resource utilization management in regional viticulture.
Background
Eicosanoid lipid mediators play key roles in type 2 immune responses, for example in allergy and asthma. Macrophages represent major producers of eicosanoids and they are key effector ...cells of type 2 immunity. We aimed to comprehensively track eicosanoid profiles during type 2 immune responses to house dust mite (HDM) or helminth infection and to identify mechanisms and functions of eicosanoid reprogramming in human macrophages.
Methods
We established an LC‐MS/MS workflow for the quantification of 52 oxylipins to analyze mediator profiles in human monocyte‐derived macrophages (MDM) stimulated with HDM and during allergic airway inflammation (AAI) or nematode infection in mice. Expression of eicosanoid enzymes was studied by qPCR and western blot and cytokine production was assessed by multiplex assays.
Results
Short (24 h) exposure of alveolar‐like MDM (aMDM) to HDM suppressed 5‐LOX expression and product formation, while triggering prostanoid (thromboxane and prostaglandin D2 and E2) production. This eicosanoid reprogramming was p38‐dependent, but dectin‐2‐independent. HDM also induced proinflammatory cytokine production, but reduced granulocyte recruitment by aMDM. In contrast, high levels of cysteinyl leukotrienes (cysLTs) and 12‐/15‐LOX metabolites were produced in the airways during AAI or nematode infection in mice.
Conclusion
Our findings show that a short exposure to allergens as well as ongoing type 2 immune responses are characterized by a fundamental reprogramming of the lipid mediator metabolism with macrophages representing particularly plastic responder cells. Targeting mediator reprogramming in airway macrophages may represent a viable approach to prevent pathogenic lipid mediator profiles in allergy or asthma.
House dust mite triggers the production of cyclooxygenase metabolites (prostaglandin D2, prostaglandin E2 and thromboxane) as well as of proinflammatory cytokines in human macrophages. House dust mite‐exposed macrophages produce low levels of 5‐lipoxygenase metabolites (e.g. leukotriene B4) and suppress neutrophil recruitment.
High levels of cysteinyl leukotrienes and 12‐/15‐lipoxygenase metabolites are produced during the type 2 immune response to house dust mite or nematode parasites in the airways.
AEC: Airway epithelial cell; COX: Cyclooxygenase; cysLT: Cysteinyl leukotriene; HDM: House dust mite; HETE: Hydroxyeicosatetraenoic acid; HODE: Hydroxyoctadecadienoic acid; LOX: Lipoxygenase
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