Polycyclic aromatic hydrocarbons (PAHs) are carbon-based molecules that are ubiquitous in a variety of astrophysical objects and environments. In this work we use JWST/MIRI MRS spectroscopy of three ...Seyferts to compare their nuclear PAH emission with that of star-forming (SF) regions. This study represents the first of its kind to use sub-arcsecond angular resolution data of local luminous Seyferts (
L
bol
> 10
44.46
erg s
−1
) with a wide wavelength coverage (4.9–28.1 μm). We present an analysis of their nuclear PAH properties by comparing the observed ratios with PAH diagnostic model grids derived from theoretical spectra. Our results show that a suite of PAH features is present in the innermost parts of luminous Seyfert galaxies (∼0.45″ at 12 μm; in the inner ∼142–245 pc). We find that the nuclear regions of active galactic nuclei (AGN) lie at different positions of the PAH diagnostic diagrams, whereas the SF regions are concentrated around the average values of SF galaxies. In particular, we find that the nuclear PAH emission mainly originates in neutral PAHs. In contrast, PAH emission originating in the SF regions favours ionised PAH grains. The observed PAH ratios in the nuclear region of the AGN-dominated galaxy NGC 6552 indicate the presence of larger PAH molecules compared with those of the SF regions. Therefore, our results provide evidence that the AGN have a significant impact on the ionisation state (and probably the size) of the PAH grains on scales of ∼142–245 pc.
Background.
Theoretical definitions of sarcopenia traditionally emphasize age-related loss of muscle strength; however, most analyses of the association between strength and mobility examine strength ...at a single time point. This study sought to identify sex-specific cutpoints for muscle strength and power (at one time point) and 3-year changes in strength and power that would maximize prediction of 3-year mobility decline.
Methods.
Longitudinal analysis of 934 adults aged ≥65 years enrolled in the Invecchiare in Chianti study was conducted. Grip strength, knee extension strength, and lower extremity power were measured at baseline and 3 years postenrollment. Mobility function (gait speed and self-reported mobility disability) was measured at 3 and 6 years postenrollment. Classification and regression tree analysis was used to predict mobility decline from Years 3 to 6.
Results.
Men with knee extension strength <19.2 kg and grip strength <39.0 kg had clinically meaningful declines in gait speed of .24 m/s. Furthermore, men with power <105 W were nearly nine times more likely to develop incident mobility disability (likelihood ratio = 8.68; 95% confidence interval = 3.91, 19.44). Among women, knee extension strength <18.0 kg was associated with a minimal gait speed decline of 0.06 m/s, and women with leg power <64 W were three times more likely to develop incident mobility disability (likelihood ratio = 3.01; 95% confidence interval = 1.79, 5.08). Three-year changes in strength and power did not predict mobility decline in either sex.
Conclusions.
Findings suggest that strength and power measured at one time point are more predictive of mobility decline than 3-year changes and that low strength and power are particularly powerful risk factors in men.
Microbial colonization can be detrimental to the integrity of metal surfaces and lead to microbiologically influenced corrosion (MIC). Biocorrosion is a serious problem for aquatic and marine ...industries in the world. In Minnesota (USA), where this study was conducted, biocorrosion severely affects the maritime transportation industry. The anticorrosion activity of a variety of compounds, including chemical (magnesium peroxide) and biological (surfactin, capsaicin, and gramicidin) molecules were investigated as coating additives. We also evaluated a previously engineered, extremely stable, non-biocidal enzyme known to interfere in bacterial signaling, SsoPox (a quorum quenching lactonase). Experimental steel coupons were submerged in water from the Duluth Superior Harbor (DSH) for 8 weeks in the laboratory. Biocorrosion was evaluated by counting the number and the coverage of corrosion tubercles on coupons and also by ESEM imaging of the coupon surface. Three experimental coating additives significantly reduced the formation of corrosion tubercles: surfactin, magnesium peroxide and the quorum quenching lactonase by 31%, 36% and 50%, respectively. DNA sequence analysis of the V4 region of the bacterial 16S rRNA gene revealed that these decreases in corrosion were associated with significant changes in the composition of bacterial communities on the steel surfaces. These results demonstrate the potential of highly stable quorum quenching lactonases to provide a reliable, cost-effective method to treat steel structures and prevent biocorrosion.
No gold standard exists for identifying successful outcomes 1 and 2 years after operative and non-operative management of anterior cruciate ligament (ACL) injury. This limits the ability of a ...researcher and clinicians to compare and contrast the results of interventions.
To establish a consensus based on expert consensus of measures that define successful outcomes 1 and 2 years after ACL injury or reconstruction.
Members of international sports medicine associations, including the American Orthopaedic Society for Sports Medicine, the European Society for Sports Traumatology, Surgery, and Knee Arthroscopy and the American Physical Therapy Association, were sent a survey via email. Blinded responses were analysed for trends with frequency counts. A summed importance percentage (SIP) was calculated and 80% SIP operationally indicated consensus.
1779 responses were obtained. Consensus was achieved for six measures in operative and non-operative management: the absence of giving way, patient return to sports, quadriceps and hamstrings' strength greater than 90% of the uninvolved limb, the patient having not more than a mild knee joint effusion and using patient-reported outcomes (PRO). No single PRO achieved consensus, but threshold scores between 85 and 90 were established for PROs concerning patient performance.
The consensus identified six measures important for successful outcome after ACL injury or reconstruction. These represent all levels of the International Classification of Functioning: effusion, giving way, muscle strength (body structure and function), PRO (activity and participation) and return to sport (participation), and should be included to allow for comparison between interventions.
In a matched sample of Seyfert and quiescent galaxies we simultaneously probe the stellar and molecular gas kinematics from 1 kpc down to 50 pc with the aim of identifying the dynamical processes ...dictating black hole accretion rates. This first paper compares the global characteristics of a sample of 10 galaxies. We find several differences within a radius of 500 pc that are correlated with active galactic nucleus (AGN) activity. The Seyferts have (1) a more centrally concentrated nuclear stellar surface brightness with lower stellar luminosities beyond a radius of 100 pc, (2) a lower stellar velocity dispersion within a radius of 200 pc, (3) elevated H sub(2) 1-0 S(1) luminosity out to a radius of at least 250 pc, and (4) more centrally concentrated H sub(2) surface brightness profiles. These observed differences can be interpreted as evidence for Seyfert galaxies having a dynamically cold (in comparison to the bulge) nuclear structure composed of a significant gas reservoir and a relatively young stellar population. This structure is undetected (and possibly does not exist) in quiescent galaxies. The presence of such a nuclear structure in Seyfert galaxies provides evidence for inflow of the surrounding interstellar medium since the nuclear stellar population requires a supply of gas from which to form. The fueling of a Seyfert AGN is thus associated with the formation of a dynamically cold component of gas and stars on scales of hundreds of parsecs.
The magnitude of carbon (C) loss to the atmosphere via microbial
decomposition is a function of the amount of C stored in soils, the quality
of the organic matter, and physical, chemical, and ...biological factors that
comprise the environment for decomposition. The decomposability of C is
commonly assessed by laboratory soil incubation studies that measure
greenhouse gases mineralized from soils under controlled conditions. Here,
we introduce the Soil Incubation Database (SIDb) version 1.0, a compilation
of time series data from incubations, structured into a new, publicly
available, open-access database of C flux (carbon dioxide, CO2, or
methane, CH4). In addition, the SIDb project also provides a platform
for the development of tools for reading and analysis of incubation data as
well as documentation for future use and development. In addition to
introducing SIDb, we provide reporting guidance for database entry and the
required variables that incubation studies need at minimum to be included in
SIDb. A key application of this synthesis effort is to better characterize
soil C processes in Earth system models, which will in turn reduce our
uncertainty in predicting the response of soil C decomposition to a changing
climate. We demonstrate a framework to fit curves to a number of incubation
studies from diverse ecosystems, depths, and organic matter content using a
built-in model development module that integrates SIDb with the existing
SoilR package to estimate soil C pools from time series data. The database
will help bridge the gap between point location measurements, which are
commonly used in incubation studies, and global remote-sensed data or data
products derived from models aimed at assessing global-scale rates of
decomposition and C turnover. The SIDb version 1.0 is archived and publicly
available at https://doi.org/10.5281/zenodo.3871263 (Sierra et al., 2020), and the database is managed
under a version-controlled system and centrally stored in GitHub (https://github.com/SoilBGC-Datashare/sidb, last access: 26 June 2020).
Although the incorporation of research biopsies into clinical trials is increasing, limited information is available about how study protocols and informed consents integrate and describe their use.
...All therapeutic clinical trials in which image-guided research biopsies were performed from January 1, 2005, to October 1, 2010, were identified from an interventional radiology database. Data from study protocols and informed consents were extracted and analyzed. Procedural complications were recorded.
A total of 57 clinical trials were identified, of which 38 (67%) contained at least one mandatory biopsy. The analysis of the research biopsy tumor tissue was a study end point in 95% of trials. The primary indication for a research biopsy was for integral biomarker analysis in 32% and for correlative science in 68% of trials. A statistical analytic plan for the correlative science research biopsy tumor tissue was mentioned in 26%, described as exploratory in 51%, and not mentioned in 23% of trials. For studies with mandatory biopsies, biopsy was an eligibility criterion in 71% of trials, and a statistical justification for the research biopsy sample size was present in 50% of trials. A total of 745 research biopsies were performed on 576 patients. Overall and major complication rates were 5.2% (39 of 745 biopsies) and 0.8% (six of 745 biopsies), respectively. Complication rates for intrathoracic and abdominal/pelvic solid organ biopsies were 17.1% (36 of 211 biopsies) and 1.6% (three of 189 biopsies), respectively. Site-stratified research biopsy-related risks were discussed in five consents.
A better representation of the risks and benefits of research biopsies in study protocols and informed consents is needed.
In a sample of local active galactic nuclei (AGNs) studied at a spatial resolution on the order of 10 pc, we show that the interstellar medium traced by the molecular hydrogen n = 1-0 S(1) line at ...2.1 mm forms a geometrically thick, clumpy disk. The kinematics of the molecular gas reveals general rotation, although an additional significant component of random bulk motion is required by the high local velocity dispersion. The size scale of the typical gas disk is found to have a radius of ~30 pc with a comparable vertical height. Within this radius, the average gas mass is estimated to be ~107 M based on a typical gas mass fraction of 10%, which suggests column densities of N H ~ 5 X 1023 cm-2. Extinction of the stellar continuum within this same region suggests lower column densities of N H ~2 X 1022 cm-2, indicating that the gas distribution on these scales is dominated by dense clumps. In half of the observed Seyfert galaxies, this lower column density is still great enough to obscure the AGN at optical/infrared wavelengths. We conclude, based on the spatial distribution, kinematics, and column densities that the molecular gas observed is spatially mixed with the nuclear stellar population and is likely to be associated with the outer extent of any smaller scale nuclear obscuring structure. Furthermore, we find that the velocity dispersion of the molecular gas is correlated with the star formation rate per unit area, suggesting a link between the two phenomena, and that the gas surface density follows known 'Schmidt-Kennicutt' relations. The molecular/dusty structure on these scales may be dynamic since it is possible that the velocity dispersion of the gas, and hence the vertical disk height, is maintained by a short, massive inflow of material into the nuclear region and/or by intense, short-lived nuclear star formation.
We investigate the relation between the detection of the 11.3
μ
m polycyclic aromatic hydrocarbon (PAH) feature in the nuclear (∼24−230 pc) regions of 22 nearby Seyfert galaxies and the properties ...of the cold molecular gas. For the former we use ground-based (0.3−0.6″ resolution) mid-infrared (mid-IR) spectroscopy. The cold molecular gas is traced by ALMA and NOEMA high (0.2−1.1″) angular resolution observations of the CO(2–1) transition. Galaxies with a nuclear detection of the 11.3
μ
m PAH feature contain more cold molecular gas (median 1.6 × 10
7
M
⊙
) and have higher column densities (
N
(H
2
) = 2 × 10
23
cm
−2
) over the regions sampled by the mid-IR slits than those without a detection. This suggests that molecular gas plays a role in shielding the PAH molecules in the harsh environments of Seyfert nuclei. Choosing the PAH molecule naphthalene as an illustration, we compute its half-life in the nuclear regions of our sample when exposed to 2.5 keV hard X-ray photons. We estimate shorter half-lives for naphthalene in nuclei without a 11.3
μ
m PAH detection than in those with a detection. The
Spitzer
/IRS PAH ratios on circumnuclear scales (∼4″ ∼ 0.25−1.3 kpc) are in between model predictions for neutral and partly ionized PAHs. However, Seyfert galaxies in our sample with the highest nuclear H
2
column densities are not generally closer to the neutral PAH tracks. This is because in the majority of our sample galaxies, the CO(2–1) emission in the inner ∼4″ is not centrally peaked and in some galaxies traces circumnuclear sites of strong star formation activity. Spatially resolved observations with the MIRI medium-resolution spectrograph on the
James Webb
Space Telescope will be able to distinguish the effects of an active galactic nucleus (AGN) and star formation on the PAH emission in nearby AGN.
We use high-spectral resolution (R > 8000) data covering 3800–13 000 Å to study the physical conditions of the broad-line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad H i lines are ...present in each spectrum. A comparison – for the first time using simultaneous optical to near-infrared observations – to photoionization calculations with our devised simple scheme yields the extinction to the BLR at the same time as determining the density and photon flux, and hence distance from the nucleus, of the emitting gas. This points to a typical density for the H i emitting gas of 1011 cm−3 and shows that a significant amount of this gas lies at regions near the dust sublimation radius, consistent with theoretical predictions. We also confirm that in many objects, the line ratios are far from case B, the best-fitting intrinsic broad-line Hα/H β ratios being in the range 2.5–6.6 as derived with our photoionization modelling scheme. The extinction to the BLR, based on independent estimates from H i and He ii lines, is A
V
≤ 3 for Seyfert 1–1.5s, while Seyfert 1.8–1.9s have A
V
in the range 4–8. A comparison of the extinction towards the BLR and narrow-line region (NLR) indicates that the structure obscuring the BLR exists on scales smaller than the NLR. This could be the dusty torus, but dusty nuclear spirals or filaments could also be responsible. The ratios between the X-ray absorbing column N
H and the extinction to the BLR are consistent with the Galactic gas-to-dust ratio if N
H variations are considered.
PDF
