73 research outputs found
A Deep Chandra ACIS Study of NGC 4151. III. the Line Emission and Spectral Analysis of the Ionization Cone
This paper is the third in a series in which we present deep Chandra ACIS-S
imaging spectroscopy of the Seyfert 1 galaxy NGC 4151, devoted to study its
complex circum-nuclear X-ray emission. Emission features in the soft X-ray
spectrum of the bright extended emission (L[0.3-2keV]~10^40 erg/s) at r>130 pc
(2") are consistent with the brighter OVII, OVIII, and NeIX lines seen in the
Chandra HETGS and XMM-Newton RGS spectra below 2 keV. We construct emission
line images of these features and find good morphological correlations with the
narrow line region clouds mapped in [OIII]5007A. Self-consistent
photoionization models provide good descriptions of the spectra of the large
scale emission, as well as resolved structures, supporting the dominant role of
nuclear photoionization, although displacement of optical and X-ray features
implies a more complex medium. Collisionally ionized emission is estimated to
be <12% of the extended emission. Presence of both low and high ionization
spectral components and extended emission in the X-ray image perpendicular to
the bicone indicates leakage of nuclear ionization, likely filtered through
warm absorbers, instead of being blocked by a continuous obscuring torus. The
ratios of [OIII]/soft X-ray flux are approximately constant (~15) for the 1.5
kpc radius spanned by these measurements, indicating a relatively constant
ionization parameter, consistent with the photoionized outflow of a wind-like
density profile. Using spatially resolved features, we estimate that the mass
outflow rate in NGC 4151 is ~2Msun/yr at 130 pc and the kinematic power of the
ionized outflow is 1.7x10^41 erg/s, approximately 0.3% of the bolometric
luminosity of NGC 4151.Comment: 45 pages. 18 figures. Accepted to Ap
A Deep Chandra ACIS Study of NGC 4151. II. The Innermost Emission Line Region and Strong Evidence for Radio Jet-NLR Cloud Collision
We have studied the X-ray emission within the inner 150 pc radius of NGC 4151
by constructing high spatial resolution emission line images of OVII, OVIII,
and NeIX. These maps show extended structures that are spatially correlated
with the radio outflow and optical [OIII] emission. We find strong evidence for
jet--gas cloud interaction, including morphological correspondences with
regions of X-ray enhancement, peaks of near-infrared [FeII] emission, and
optical clouds. In these regions, moreover, we find evidence of elevated
NeIX/OVII ratios; the X-ray emission of these regions also exceeds that
expected from nuclear photoionization. Spectral fitting reveals the presence of
a collisionally ionized component. The thermal energy of the hot gas suggests
that >0.1% of the estimated jet power is deposited into the host interstellar
medium through interaction between the radio jet and the dense medium of the
circum-nuclear region. We find possible pressure equilibrium between the
collisionally ionized hot gas and the photoionized line-emitting cool clouds.
We also obtain constraints on the extended iron and silicon fluorescent
emission. Both lines are spatially unresolved. The upper limit on the
contribution of an extended emission region to the Fe Kalpha emission is <5% of
the total, in disagreement with a previous claim that 65% of the Fe Kalpha
emission originates in the extended narrow line region.Comment: Accepted for publication in ApJ. 28 pages, 9 figure
A Deep Chandra ACIS Study of NGC 4151. I. the X-ray Morphology of the 3 kpc-diameter Circum-nuclear Region and Relation to the Cold Interstellar Medium
We report on the imaging analysis of 200 ks sub-arcsecond resolution Chandra
ACIS-S observations of the nearby Seyfert 1 galaxy NGC 4151. Bright, structured
soft X-ray emission is observed to extend from 30 pc to 1.3 kpc in the
south-west from the nucleus, much farther than seen in earlier X-ray studies.
The terminus of the north-eastern X-ray emission is spatially coincident with a
CO gas lane, where the outflow likely encounters dense gas in the host galactic
disk. X-ray emission is also detected outside the boundaries of the ionization
cone, which indicates that the gas there is not completely shielded from the
nuclear continuum, as would be the case for a molecular torus collimating the
bicone. In the central r<200 pc region, the subpixel processing of the ACIS
data recovers the morphological details on scales of <30~pc (<0.5") first
discovered in Chandra HRC images. The X-ray emission is more absorbed towards
the boundaries of the ionization cone, as well as perpendicular to the bicone
along the direction of a putative torus in NGC 4151. The innermost region where
X-ray emission shows the highest hardness ratio, is spatially coincident with
the near-infrared resolved H_2 emission and dusty spirals we find in an HST V-H
color image. The agreement between the observed H_2 line flux and the value
predicted from X-ray-irradiated molecular cloud models supports
photo-excitation by X-rays from the active nucleus as the origin of the H_2
line, although contribution from UV fluorescence or collisional excitation
cannot be fully ruled out with current data. The discrepancy between the mass
of cold molecular gas inferred from recent CO and near-infrared H_2
observations may be explained by the anomalous CO abundance in this X-ray
dominated region. The total H_2 mass derived from the X-ray observation agrees
with measurement in Storchi-Bergmann et al.Comment: 33 pages, 9 figures and 2 table
HHV-6 Specific T-Cell Immunity in Healthy Children and Adolescents
Objective: Primary infection with human herpes virus 6 (mainly HHV-6B) commonly occurs in the first 2 years of life leading to persistence and the possibility of virus reactivation later in life. Consequently, a specific cellular immune response is essential for effective control of virus reactivation. We have studied cell-mediated immune response to HHV-6 (U54) in healthy children and adolescents.Materials and Methods: By flow cytometry, the amount of cytokine (interferon gammaâIFN- Îł, interleukin 2âIL-2, tumor necrosis factor alphaâTNF-α) secreting T-cells were measured after 10 days of pre-sensitization and 6 h of re-stimulation with mixtures of pooled overlapping peptides from U54, staphylococcal enterotoxin B (SEB, positive control), or Actin (negative control) in healthy children and adolescents without any underlying immune disorder or infectious disease.Results: All individuals showed a virus-specific response for at least one cytokine in either CD4+ or CD8+ cells. Percentages of individuals with HHV-6-specific TNF-α response in CD4+ (48% of individuals) as well as CD8+ (56% of individuals) were always the highest. Our data show significantly higher frequencies of HHV-6-specific TNF-α producing CD8+ T-cells in individuals older than 10 years of life (p = 0.033). Additionally, the frequency of HHV-6 specific TNF-α producing CD8+ T-cells positively correlated with the age of the individuals. Linear regression analysis showed a positive relation between age and frequency of HHV-6-specific TNF-α producing CD8+ T-cells.Conclusion: Results indicate that T-cell immune response against HHV-6 is commonly detectable in healthy children and adolescents with higher frequencies of antigen-specific T-cells in older children and adolescents possibly reflecting repeated stimulation by viral persistence and subclinical reactivation
Patient-reported outcome measures for knowledge transfer and behaviour modification interventions in type 2 diabetes-the INDICA study: a multiarm cluster randomised controlled trial
Objective: This study assesses the effectiveness of different interventions of knowledge transfer and behaviour modification to improve type 2 diabetes mellitus patients' (T2DM) reported outcomes measures (PROMs) in the long-term. Design: open, community-based pragmatic, multicentre, controlled trial with random allocation by clusters to usual care (UC) or to one of the three interventions. Participants: A total of 2334 patients with uncomplicated T2DM and 211 healthcare professionals were included of 32 primary care centres. Setting: Primary Care Centers in Canary Islands (Spain). Intervention: The intervention for patients (PTI) included an educational group programme, logs and a web-based platform for monitoring and automated short message service (SMS). The intervention for professionals (PFI) included an educational programme, a decision support tool embedded into the electronic clinical record and periodic feedback about patients' results. A third group received both PTI and PFI (combined intervention, CBI). Outcome measure: Cognitive-attitudinal, behavioural, affective and health-related quality of life (HQoL) variables. Results: Compared with UC at 24 months, the PTI group significantly improved knowledge (p=0.005), self-empowerment (p=0.002), adherence to dietary recommendations (p<0.001) and distress (p=0.01). The PFI group improved at 24 months in distress (p=0.03) and at 12 months there were improvements in depression (p=0.003), anxiety (p=0.05), HQoL (p=0.005) and self-empowerment (p<0.001). The CBI group improved at 24 months in self-empowerment (p=0.008) and adherence to dietary recommendations (p=0.004) and at 12 months in knowledge (p=0.008), depression (p=0.006), anxiety (p=0.003), distress (p=0.01), HQoL (p<0.001) and neuropathic symptoms (p=0.02). Statistically significant improvements were also observed at 24 months in the proportion of patients who quit smoking for PTI and CBI (41.5% in PTI and 42.3% in CBI vs 21.2% in the UC group). Conclusions: Assessed interventions to improve PROMs in T2DM attain effectiveness for knowledge, self-empowerment, distress, diet adherence and tobacco cessation. PTI produced the most lasting benefits. Trial registration number: ClinicalTrials.gov NCT01657227 (6 August 2012) https://clinicaltrials.gov/ct2/show/NCT01657227.This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness (Instituto de Salud Carlos III), grant number: ADE10/00032 and PI16/00769 co-funded by the European Regional Development Fund (ERDF) âA way to make Europeâ.S
Recovery and Recycling of Chiral Iridium(N,P Ligand) Catalysts from Hydrogenation Reactions
Despite the high efficiency and broad scope of chiral iridium(N,P ligand) complexes as catalysts for asymmetric hydrogenation, the problem of catalyst recovery and recycling has so far attracted little attention. We have found that at the end of a hydrogenation reaction, iridium(N,P ligand) catalysts form dimeric Ir(III) dihydride complexes, which can be converted back to the original precatalysts by addition of COD. Based on these findings, a practically simple protocol for catalyst recovery was devised. The recovered complexes showed essentially the same reactivity and enantioselectivity as the original catalysts. Especially large-scale applications and hydrogenations of less reactive substrates that require high catalyst loadings will benefit from this protocol that allows recovery and reuse of expensive iridium complexes
Drought-induced modifications of photosynthetic electron transport in intact leaves: Analysis and use of neural networks as a tool for a rapid non-invasive estimation
AbstractWater deficit is one of the most important environmental factors limiting sustainable crop yields and it requires a reliable tool for fast and precise quantification. In this work we use simultaneously recorded signals of photoinduced prompt fluorescence (PF) and delayed fluorescence (DF) as well as modulated reflection (MR) of light at 820nm for analysis of the changes in the photosynthetic activity in detached bean leaves during drying. Depending on the severity of the water deficit we identify different changes in the primary photosynthetic processes. When the relative water content (RWC) is decreased to 60% there is a parallel decrease in the ratio between the rate of excitation trapping in the Photosystem (PS) II reaction center and the rate of reoxidation of reduced PSII acceptors. A further decrease of RWC to 20% suppresses the electron transfer from the reduced plastoquinone pool to the PSI reaction center. At RWC below values 15%, the reoxidation of the photoreduced primary quinone acceptor of PSII, QAâ, is inhibited and at less than 5%, the primary photochemical reactions in PSI and II are inactivated. Using the collected sets of PF, DF and MR signals, we construct and train an artificial neural network, capable of recognizing the RWC in a series of âunknownâ samples with a correlation between calculated and gravimetrically determined RWC values of about R2â0.98. Our results demonstrate that this is a reliable method for determination of RWC in detached leaves and after further development it could be used for quantifying of drought stress of crop plants in situ. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial
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