28 research outputs found
MASSIV: Mass Assembly Survey with SINFONI in VVDS - II. Kinematics and close environment classification
(Abridged) Processes driving mass assembly are expected to evolve on
different timescales along cosmic time. A transition might happen around z ~ 1
as the cosmic star formation rate starts its decrease. Identifying the
dynamical nature of galaxies on a representative sample is necessary to infer
and compare the mass assembly mechanisms across cosmic time. We present an
analysis of the kinematics properties of 50 galaxies with 0.9 < z < 1.6 from
the MASSIV sample observed with SINFONI/VLT with 4.5x10^9 Msun < M < 1.7x10^11
Msun and 6 Msun/yr < SFR < 300 Msun/yr. This is the largest sample with
2D-kinematics in this redshift range. We provide a classification based on
kinematics as well as on close galaxy environment. We find that 29% of galaxies
are experiencing merging or have close companions that may be gravitationally
linked. This is placing a lower limit on the fraction of interacting galaxies.
We find that at least 44% of the galaxies display ordered rotation whereas at
least 35% are non-rotating objects. All rotators except one are compatible with
rotation-dominated (Vmax/sigma > 1) systems. Non-rotating objects are mainly
small objects (Re < 4 kpc). Combining our sample with other 3D-spectroscopy
samples, we find that the local velocity dispersion of the ionized gas
component decreases continuously from z ~ 3 to z = 0. The proportion of disks
also seems to be increasing in star-forming galaxies when the redshift
decreases. The number of interacting galaxies seems to be at a maximum at z ~
1.2. These results draw a picture in which cold gas accretion may still be
efficient at z ~ 1.2 but in which mergers may play a much more significant role
at z ~ 1.2 than at higher redshift. From a dynamical point of view, the
redshift range 1 < z < 2 therefore appears as a transition period in the galaxy
mass assembly process.Comment: 23 pages (+29 maps pages), 7 figures, language corrections and
reference updates included, A&A in pres
Increased expression of endothelial lipase in symptomatic and unstable carotid plaques
The aim of this study was to evaluate endothelial lipase (EL) protein expression in advanced human carotid artery plaques (HCAP) with regard to plaque (in)stability and the incidence of symptoms. HCAP were collected from 66 patients undergoing carotid endarterectomy (CEA). The degree of plaque (in)stability was estimated by ultrasound and histology. In HCAP sections, EL expression was determined by immunostaining and the intensity was assessed on a semi-quantitative scale (low: <25%, high: >25% positive cells). Monocytes and macrophages in adjacent HCAP sections were stained with a CD163 specific antibody. High EL staining was more prevalent in histologically unstable plaques (in 33.3% of fibrous plaques, 50% of ulcerated non-complicated plaques and 79.2% of ulcerated complicated plaques; χ2 test, p = 0.004) and in the symptomatic group (70.8 vs. 42.9% in the asymptomatic group; χ2 test, p = 0.028). The majority of EL immunostaining was found in those HCAP regions exhibiting a strong CD163 immunostaining. EL in HCAP might be a marker and/or promoter of plaque instability and HCAP-related symptomatology
Azithromycin does not prevent six-month myointimal proliferation but attenuates the transient systemic inflammation occurring after coronary stenting
Stent implantation produces a systemic increase of inflammatory markers that correlates with Chlamydophila pneumoniae infection in atherosclerotic plaque. We performed a clinical intervention study to investigate the effect of antibiotic treatment on 6-month follow-up angiographic minimal luminal diameter after stenting. Ninety patients were randomly assigned to oral azithromycin or placebo in a double-blinded and randomized fashion. Medication was initiated 2 weeks before a pre-scheduled stenting procedure and maintained 12 weeks thereafter. Angiographic outcomes were evaluated by a six-month follow-up angiography and laboratorial parameters were accessed by blood sampling 2 weeks before stenting, within the first 24 h after procedure and additional samples after four weeks and 6 months. Minimal luminal diameter (1.76 +/- A 0.56 mm Vs. 1.70 +/- A 0.86 mm; P = 0.7), restenosis rate, diameter stenosis, late loss, and binary restenosis rates were comparable in placebo and azithromycin group in the 6 months follow-up. Serum levels of C-reactive protein presented a three fold significant increase in the control group one day after stenting but did not change in the azithromycin group (8.5 [3.0;16.4] Vs. 2.9 [1.7;6.6]-median [25;75 percentile] P < 0.01). Azithromycin does not improve late angiographic outcomes but attenuates the elevation of C-reactive protein levels after stenting, indicating an anti-inflammatory effect