Spherical carbons have been prepared through hydrothermal treatment of three carbohydrates (glucose, saccharose and cellulose). Preparation variables such as treatment time, treatment temperature and ...concentration of carbohydrate have been analyzed to obtain spherical carbons. These spherical carbons can be prepared with particle sizes larger than 10μm, especially from saccharose, and have subsequently been activated using different activation processes (H3PO4, NaOH, KOH or physical activation with CO2) to develop their textural properties. All these spherical carbons maintained their spherical morphology after the activation process, except when KOH/carbon ratios higher than 4/1 were used, which caused partial destruction of the spheres. The spherical activated carbons develop interesting textural properties with the four activating agents employed, reaching surface areas up to 3100m2/g. Comparison of spherical activated carbons obtained with the different activating agents, taking into account the yields obtained after the activation process, shows that phosphoric acid activation produces spherical activated carbons with higher developed surface areas. Also, the spherical activated carbons present different oxygen groups’ content depending on the activating agent employed (higher surface oxygen groups content for chemical activation than for physical activation).
ABSTRACT
We present the discovery with Keck of the extremely infrared (IR) luminous transient AT 2017gbl, coincident with the Northern nucleus of the luminous infrared galaxy (LIRG) IRAS 23436+5257. ...Our extensive multiwavelength follow-up spans ∼900 d, including photometry and spectroscopy in the optical and IR, and (very long baseline interferometry) radio and X-ray observations. Radiative transfer modelling of the host galaxy spectral energy distribution and long-term pre-outburst variability in the mid-IR indicate the presence of a hitherto undetected dust obscured active galactic nucleus (AGN). The optical and near-IR spectra show broad ∼2000 km s−1 hydrogen, He i, and O i emission features that decrease in flux over time. Radio imaging shows a fast evolving compact source of synchrotron emission spatially coincident with AT 2017gbl. We infer a lower limit for the radiated energy of 7.3 × 1050 erg from the IR photometry. An extremely energetic supernova would satisfy this budget, but is ruled out by the radio counterpart evolution. Instead, we propose AT 2017gbl is related to an accretion event by the central supermassive black hole, where the spectral signatures originate in the AGN broad line region and the IR photometry is consistent with re-radiation by polar dust. Given the fast evolution of AT 2017gbl, we deem a tidal disruption event (TDE) of a star a more plausible scenario than a dramatic change in the AGN accretion rate. This makes AT 2017gbl the third TDE candidate to be hosted by a LIRG, in contrast to the so far considered TDE population discovered at optical wavelengths and hosted preferably by post-starburst galaxies.
Abstract
The obligatory biotrophic oomycetes Plasmopara viticola is the causal agent of downy mildew, a destructive disease of grapevine worldwide. So far, chemical fungicides are widely employed to ...limit this pathogen, but their adverse effects are stimulating the quest for environmentally friendly alternative approaches. Here, we report on the search for mycoviruses that might be later developed as biocontrol agents for this pathogen. Symptomatic leaves were collected from various regions in Spain and Italy and mycelia associated to leaf lesions was harvested. Total RNA extractions were depleted of rRNA and metatranscriptomes were generated using a high-throughput sequencing approach. The virome associated to leaf lesions was then characterized through a bioinformatic pipeline relying on blast searches against current viral databases. Here, we present an inventory of 283 new RNA viruses: 222 positive strand RNA viruses, 29 negative strand RNA viruses, 27 double-stranded RNA viruses and 5 ORFan virus RdRP segments, which could not be reliably assigned to any existing group in the Riboviria. In addition to ORFan viruses, we found other surprising new evolutionary trajectories in this wide inventory of viruses. The most represented viruses in our collection are those in phylum Lenarviricota, and, among them, a group of mycovirus segments distantly related to narnaviruses, but characterized by a polymerase palm domain lacking subdomain C, with the putative GDD catalytic triad. We also provided evidence of a strict association between two RNA segments that form a new mycovirus clade of positive strand RNA in the phylum Kitrinoviricota, order Martellivirales. In the phylum Negarnaviricota, we report for the first time in the order Mononegavirales a clade of viruses that is ambisense, a feature that so far was present only in the order Bunyavirales. Furthermore, in the same phylum we detected the widespread occurrence and abundant accumulation in our libraries of a distinct mycovirus clade distantly related to the Muvirales and Goujanvirales orders, which so far include only viruses infecting invertebrates. Possible new oomycetes-specific virus clades are also described in the phylum Duplornaviricota. These data greatly expand the evolutionary history of mycoviruses adding new layers of diversity to the realm Riboviria.
Summary
Background
The malignant mechanisms that control the development of cutaneous T‐cell lymphoma (CTCL) are beginning to be identified. Recent evidence suggests that disturbances in specific ...intracellular signalling pathways, such as RAS–mitogen‐activated protein kinase, T‐cell receptor (TCR)–phospholipase C gamma 1 (PLCG1)–nuclear factor of activated T cells (NFAT) and Janus kinase (JAK)–signal transducer and activator of transcription (STAT), may play an essential role in the pathogenesis of CTCL.
Objectives
To investigate the mechanisms controlling disease development and progression in mycosis fungoides (MF), the most common form of CTCL.
Methods
We collected 100 samples that were submitted for diagnosis of, or a second opinion regarding, MF between 2001 and 2018, 80% of which were in the early clinical stages of the disease. Formalin‐fixed paraffin‐embedded tissues were used for histological review and to measure the expression by immunohistochemistry of surrogate markers of activation of the TCR–PLCG1–NFAT, JAK–STAT and NF‐κB pathways. Folliculotropism and large‐cell transformation were also examined.
Results
NFAT and nuclear factor kappa B (NF‐κB) markers showed a comparable activation status in early and advanced stages, while STAT3 activation was more frequent in advanced stages and was associated with large‐cell transformation. Consistently with this observation, STAT3 activation occurred in parallel with MF progression in two initially MF‐negative cases. A significant association of NFAT with NF‐κB markers was also found, reflecting a common mechanism of activation in the two pathways. Genomic studies identified nine mutations in seven genes known to play a potential role in tumorigenesis in T‐cell leukaemia/lymphoma, including PLCG1, JAK3 and STAT3, which underlies the activation of these key cell‐survival pathways. A higher mutational allele frequency was detected in advanced stages.
Conclusions
Our results show that STAT3 is activated in advanced cases and is associated with large‐cell transformation, while the activation of NFAT and NF‐κB is maintained throughout the disease. These findings could have important diagnostic and therapeutic implications.
What's already known about this topic?
Mycosis fungoides is characterized by a clonal expansion of T cells in the skin.
The mechanisms controlling disease development and progression are not fully understood.
What does this study add?
An association of the nuclear factor of activated T cells and nuclear factor kappa B pathways was found, which could reflect a common mechanism of activation. These pathways were activated in early and advanced stages at the same level.
Signal transducer and activator of transcription 3 activation was associated with large‐cell transformation and was more frequent in advanced stages.
A genomic analysis of cutaneous T‐cell lymphoma‐associated genes was performed. Nine mutations were detected.
What is the translational message?
These results could have important implications for the treatment of MF in the near future.
Linked Comment: Ødum. Br J Dermatol 2020; 182:16–17.
In spite of the extensive potential of human mesenchymal stem cells (hMSCs) in cell therapy, little is known about the molecular mechanisms that regulate their therapeutic properties. We aimed to ...identify microRNAs (miRNAs) involved in controlling the transition between the resting and reparative phenotypes of hMSCs, hypothesizing that these miRNAs must be present in the undifferentiated cells and downregulated to allow initiation of distinct activation/differentiation programs. Differential miRNA expression analyses revealed that miR-335 is significantly downregulated upon hMSC differentiation. In addition, hMSCs derived from a variety of tissues express miR-335 at a higher level than human skin fibroblasts, and overexpression of miR-335 in hMSCs inhibited their proliferation and migration, as well as their osteogenic and adipogenic potential. Expression of miR-335 in hMSCs was upregulated by the canonical Wnt signaling pathway, a positive regulator of MSC self-renewal, and downregulated by interferon-γ (IFN-γ), a pro-inflammatory cytokine that has an important role in activating the immunomodulatory properties of hMSCs. Differential gene expression analyses, in combination with computational searches, defined a cluster of 62 putative target genes for miR-335 in hMSCs. Western blot and 3'UTR reporter assays confirmed RUNX2 as a direct target of miR-335 in hMSCs. These results strongly suggest that miR-335 downregulation is critical for the acquisition of reparative MSC phenotypes.
BACKGROUND AND PURPOSE NO produced by endothelial NOS is needed for normal vascular function. During diabetes, aging and hypertension, elevated levels of arginase can compete with NOS for available ...l‐arginine, reducing NO and increasing superoxide (O2.−) production via NOS uncoupling. Elevated O2.− combines with NO to form peroxynitrite (ONOO‐), further reducing NO. Oxidative species increase arginase activity, but the mechanism(s) involved are not known. Our study determined the mechanism involved in peroxynitrite and hydrogen peroxide‐induced enhancement in endothelial arginase activity. We hypothesized that oxidative species increase arginase activity through PKC‐activated RhoA/Rho kinase (ROCK) pathway.
EXPERIMENTAL APPROACH Arginase activity/expression was analysed in bovine aortic endothelial cells (BAEC) treated with an ONOO‐ generator (SIN‐1) or H2O2. Pretreatment with inhibitors of Rho kinase (Y‐27632) or PKC (Gö6976) was used to investigate the mechanism involved in arginase activation.
KEY RESULTS Exposure to SIN‐1 (25 µM, 24 h) or H2O2 (25 µM, 8 h) increased arginase I expression and arginase activity (35% and 50%, respectively), which was prevented by ROCK inhibitor, Y‐27632, PKC inhibitor, Gö6976 or siRNA to p115‐Rho GEF. There was an early activation of p115‐Rho GEF (SIN‐1, 2 h; H2O2, 1 h) and Rho A (SIN‐1, 4 h; H2O2, 1 h) that was prevented by using the PKC inhibitor. Exposure to SIN‐1 and H2O2 also reduced NOS activity, which was blocked by pretreatment with p115‐RhoGEF siRNA.
CONCLUSIONS AND IMPLICATIONS Our data indicate that the oxidative species ONOO‐ and H2O2 increase arginase activity/expression through PKC‐mediated activation of RhoA/Rho kinase pathway.
We report the discovery of 6576 new spectroscopically confirmed white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12. We obtain T
eff, log g and mass for hydrogen atmosphere ...white dwarf stars (DAs) and helium atmosphere white dwarf stars (DBs), estimate the calcium/helium abundances for the white dwarf stars with metallic lines (DZs) and carbon/helium for carbon-dominated spectra (DQs). We found one central star of a planetary nebula, one ultracompact helium binary (AM CVn), one oxygen line-dominated white dwarf, 15 hot DO/PG1159s, 12 new cataclysmic variables, 36 magnetic white dwarf stars, 54 DQs, 115 helium-dominated white dwarfs, 148 white dwarf + main-sequence star binaries, 236 metal-polluted white dwarfs, 300 continuum spectra DCs, 230 hot subdwarfs, 2936 new hydrogen-dominated white dwarf stars, and 2675 cool hydrogen-dominated subdwarf stars. We calculate the mass distribution of all 5883 DAs with S/N ≥ 15 in DR12, including the ones in DR7 and DR10, with an average S/N = 26, corrected to the 3D convection scale, and also the distribution after correcting for the observed volume, using 1/V
max.
The objective of this work is to study the adsorption of a multicomponent gaseous mixture (acetaldehyde, formaldehyde, 2-propenal, 1,3-butadiene and benzene) in which the components are present at ...different concentration on spherical activated carbons (SACs). Attention is paid to the influence of the carbons’ properties on such adsorption, especially their porosities and distributions. For this purpose, a series of spherical activated carbons were prepared by physical activation with CO2 of a commercial spherical carbon. Their physico-chemical properties were characterized by N2 and CO2 isotherms, temperature programmed desorption and scanning electron microscopy. Measurements of the adsorption of the volatile organic compounds (VOC) mixture on SACs were performed in a flow-typed fixed bed system at room temperature under atmospheric pressure. Regarding porosity, our results show that, for this particular mixture, SACs with narrow micropore size distribution and moderate porous texture development (surface area in the range of 1000 m2/g or even lower) exhibit higher multicomponent adsorption capacities than others with much larger porosities. This can be explained considering that the VOC present in larger concentration in the mixture, aldehydes, present low adsorption affinities and their adsorption is enhanced in adsorbents with narrow micropore size distribution.
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► The maximum hydrogen production is reached at 1.9-days HRT. ► The maximum solubilized organic carbon concentration is reached at 1.9-day HRT. ► The ratio ASC/DOC allows further interpretation of ...process limitations.
The main objective of this work has been to analyze the effect of hydraulic retention time (HRT) on the hydrogen production from the organic fraction of municipal solid waste (OFMSW) coming from a full-scale mechanical–biological-treatment (MBT) plant. Furthermore, it has also been studied, simultaneously, the effect of HRT on the solubilization of organic matter.
Experiments were conducted in an anaerobic continuous stirred tank reactor (CSTR) operating at thermophilic-dry conditions (55°C and 20% in total solids concentration respectively). A decreasing sequence of nine HRTs, from 15days to 1.5days, was imposed to evaluate its influence on the hydrogen production (HP), the specific hydrogen production (SHP) and the solubilized organic matter expressed in form of acidogenic substrate as carbon (ASC), dissolved organic carbon (DOC) and dissolved acid carbon (DAC).
The results have shown that the best results were obtained at 1.9-day HRT with a feeding regime of twice a day (type-C). At these conditions, the HP and the SHP was 1.077L H2/Lreactorday and 24.3mL H2/g VSadded, respectively. Maximum concentrations obtained of solubilized organic matter were: 1201mg/L for ASC, 1936mg/L for DOC and 735mg/L for DAC.
As novelty, the parameter ASC and, specially, the ratio ASC/DOC have shown to be adequate for analyzing and interpreting the behavior of the process and, concretely, to determine if hydrolysis and acidogenesis are coupled (stable process) or decoupled (transitory stage).
The Seyfert 1 galaxy Arp 151 was monitored as part of three reverberation mapping campaigns spanning 2008-2015. We present modeling of these velocity-resolved reverberation mapping data sets using a ...geometric and dynamical model for the broad-line region (BLR). By modeling each of the three data sets independently, we infer the evolution of the BLR structure in Arp 151 over a total of 7 yr and constrain the systematic uncertainties in nonvarying parameters such as the black hole mass. We find that the BLR geometry of a thick disk viewed close to face-on is stable over this time, although the size of the BLR grows by a factor of ∼2. The dynamics of the BLR are dominated by inflow, and the inferred black hole mass is consistent for the three data sets, despite the increase in BLR size. Combining the inference for the three data sets yields a black hole mass and statistical uncertainty of log10( / ) = with a standard deviation in individual measurements of 0.13 dex.
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