216 research outputs found
Spatially resolved spectra of 3C galaxy nuclei
We present and discuss visible-wavelength long-slit spectra of four low
redshift 3C galaxies obtained with the STIS instrument on the Hubble Space
Telescope. The slit was aligned with near-nuclear jet-like structure seen in
HST images of the galaxies, to give unprecedented spatial resolution of the
galaxy inner regions. In 3C 135 and 3C 171, the spectra reveal clumpy emission
line structures that indicate outward motions of a few hundred km s
within a centrally illuminated and ionised biconical region. There may also be
some low-ionisation high-velocity material associated with 3C 135. In 3C 264
and 3C 78, the jets have blue featureless spectra consistent with their
proposed synchrotron origin. There is weak associated line emission in the
innermost part of the jets with mild outflow velocity. These jets are bright
and highly collimated only within a circumnuclear region of lower galaxy
luminosity, which is not dusty. We discuss the origins of these central regions
and their connection with relativistic jets.Comment: 15 pages incl Tables, 12 diagrams, To appear in A
Complement component 4A protein levels are negatively related to frontal volumes in patients with schizophrenia spectrum disorders
Background: Excessive C4A-gene expression may result in increased microglia-mediated synaptic pruning. As C4A overexpression is observed in schizophrenia spectrum disorders (SSD), this mechanism may account for the altered brain morphology (i.e. reduced volume and cortical thickness) and cognitive symptoms that characterize SSD. Therefore, this study investigates the association of C4A serum protein levels with brain morphology and cognition, and in particular whether this association differs between recent-onset SSD (n = 69) and HC (n = 40). Methods: Serum C4A protein levels were compared between groups. Main outcomes included total gray matter volume, mean cortical thickness and cognitive performance. Regression analysis on these outcomes included C4A level, group (SSD vs. HC), and C4A*Group interactions. All statistical tests were corrected for age, sex, BMI, and antipsychotic medication dose. Follow-up analyses were performed on separate brain regions and scores on cognitive sub-tasks. Results: The group difference in C4A levels was not statistically significant (p = 0.86). The main outcomes did not show a significant interaction effect (p > 0.13) or a C4A main effect (p > 0.27). Follow-up analyses revealed significant interaction effects for the left medial orbitofrontal and left frontal pole volumes (p < 0.001): C4A was negatively related to these volumes in SSD, but positively in HC. Conclusion: This study demonstrated that C4A was negatively related to – specifically – frontal brain volumes in SSD, but this relation was inverse for HC. The results support the hypothesis of complement-mediated brain volume reduction in SSD. The results also suggest that C4A has a differential association with brain morphology in SSD compared to HC.</p
The unfriendly ISM in the radio galaxy 4C12.50 (PKS 1345+12)
The radio source 4C12.50 has often been suggested to be a prime candidate for
the link between ultraluminous infrared galaxies and young radio galaxies. A
VLBI study of the neutral hydrogen in the nuclear regions of this object shows
that most of the gas detected close to the systemic velocity is associated with
an off-nuclear cloud (~50 to 100 pc from the radio core) with a column density
of ~10^22 T_spin/100 K) cm^(-2) and an HI mass of a few times 10^5 to 10^6
M_sun. We consider a number of possibilities to explain the results. In
particular, we discus the possibility that this cloud indicates the presence of
a rich and clumpy interstellar medium in the centre, likely left over from the
merger that triggered the activity and that this medium influences the growth
of the radio source. The location of the cloud -- at the edge of the northern
radio jet/lobe -- suggests that the radio jet might be interacting with a gas
cloud. This interaction could be responsible for bending the young radio jet.
The velocity profile of the gas is relatively broad (~150$ km/s) and we
interpret this as kinematical evidence for interaction of the radio plasma with
the cloud. We also consider the model where the cloud is part of a broader
circumnuclear structure. Only a limited region of this structure would have
sufficient background radio brightness and large enough column depth in neutral
gas to obtain detectable HI absorption against the counterjet. The VLBI study
of the neutral hydrogen in 4C12.50 suggests that HI detected near the systemic
velocity (as it is often the case in radio galaxies) may not necessarily be
connected with a circumnuclear disk or torus (as is very often assumed) but
instead could be a tracer of the large-scale medium that surrounds the active
nucleus and that may influence the growth of the young radio source.Comment: 7 pages, 2 figures. Accepted for publication in A&
Healthy ageing and depletion of intracellular glutathione influences T cell membrane thioredoxin-1 levels and cytokine secretion
Background: During ageing an altered redox balance has been observed in both intracellular and extracellular compartments, primarily due to glutathione depletion and metabolic stress. Maintaining redox homeostasis is important for controlling proliferation and apoptosis in response to specific stimuli for a variety of cells. For T cells, the ability to generate specific response to antigen is dependent on the oxidation state of cell surface and cytoplasmic protein-thiols. Intracellular thiols are maintained in their reduced state by a network of redox regulating peptides, proteins and enzymes such as glutathione, thioredoxins and thioredoxin reductase. Here we have investigated whether any relationship exists between age and secreted or cell surface thioredoxin-1, intracellular glutathione concentration and T cell surface thioredoxin 1 (Trx-1) and how this is related to interleukin (IL)-2 production.Results: Healthy older adults have reduced lymphocyte surface expression and lower circulating plasma Trx-1 concentrations. Using buthionine sulfoximine to deplete intracellular glutathione in Jurkat T cells we show that cell surface Trx-1 is lowered, secretion of Trx-1 is decreased and the response to the lectin phytohaemagglutinin measured as IL-2 production is also affected. These effects are recapitulated by another glutathione depleting agent, diethylmaleate.Conclusion: Together these data suggest that a relationship exists between the intracellular redox compartment and Trx-1 proteins. Loss of lymphocyte surface Trx-1 may be a useful biomarker of healthy ageing. © 2013 Carilho Torrao et al.; licensee Chemistry Central Ltd
Laparoscopic resection of a residual retroperitoneal tumor mass of nonseminomatous testicular germ cell tumors
Resection of a residual retroperitoneal tumor mass (RRRTM) is standard procedure after combination chemotherapy for metastatic nonseminomatous testicular germ cell tumors (NSTGCT). At the University Medical Center Groningen, 79 consecutive patients with disseminated NSTGCT were treated with cisplatin combination chemotherapy between 2005 and 2007. Laparoscopic RRRTM was performed for patients with RRTM located less than 5 cm ventrally or laterally from the aorta or the vena cava. The 29 patients who fulfilled the criteria had a median age of 25 years (range, 16-59 years). The stages of disease before chemotherapy treatment according to the Royal Marsden classification were 2A (n = 6, 21%), 2B (n = 14, 48%), 2C (n = 3, 10%), and 4 with a lymph node status of N2 (n = 6, 21%). The median duration of laparoscopy was 198 min (range, 122-325 min). The median diameter of the RRTM was 21 mm (range, 11-47 mm). Laparoscopic resection was successful for 25 patients (86%). Conversion was necessary for three patients (10%): two due to bleeding and one because of obesity. One nonplanned hand-assisted procedure (3%) also had to be performed. Histologic examination of the specimens showed fibrosis or necrosis in 12 patients (41%), mature teratoma in 16 patients (55%), and viable tumor in 1 patient (3%). The median hospital stay was 1 day (range, 1-6 days). During a median follow-up period of 47 months (29-70 months), one patient experienced an early relapse (1 month after the end of treatment) (4%). For properly selected patients, laparoscopic resection of RRTM is an improvement in the combined treatment of disseminated NSTGCT and associated with a short hospital stay, minimal morbidity, rapid recovery, and a neat cosmetic result. Long-term data to prove oncologic efficacy are awaited
An unbiased sample of bright southern Compact Steep Spectrum and Gigahertz Peaked Spectrum Sources
Compact Steep Spectrum (CSS) and Gigahertz Peaked Spectrum (GPS) sources are
classes of compact, powerful, extragalactic objects. These sources are thought
to be the earliest stages in the evolution of radio galaxies, capturing the
ignition (or, in some cases, re-ignition) of the AGN. As well as serving as
probes of the early stages of large-scale radio sources, these sources are
good, stable, amplitude calibrators for radio telescopes. We present an
unbiased flux density limited (>1.5 Jy at 2.7 GHz) catalogue of these objects
in the Southern Hemisphere, including tabulated data, radio spectra, and where
available, optical images and measurements. The catalogue contains 26 sources,
consisting of 2 new candidate and 15 known CSS sources, and 9 known GPS
sources. We present new Australia Telescope Compact Array (ATCA) data on ten of
these 26 sources, and data on a further 42 sources which were excluded from our
final sample. This bright sample will serve as a reference sample for
comparison with subsequent faint (mJy level) samples of CSS and GPS candidates
currently being compiled.Comment: Accepted by MNRAS. 13 figures and 10 tables. The full version of
Table 8 will be available online after publication by MNRAS. Boldface
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