991 research outputs found
Detection of a dense clump in a filament interacting with W51e2
In the framework of the Herschel/PRISMAS Guaranteed Time Key Program, the
line of sight to the distant ultracompact HII region W51e2 has been observed
using several selected molecular species. Most of the detected absorption
features are not associated with the background high-mass star-forming region
and probe the diffuse matter along the line of sight. We present here the
detection of an additional narrow absorption feature at ~70 km/s in the
observed spectra of HDO, NH3 and C3. The 70 km/s feature is not uniquely
identifiable with the dynamic components (the main cloud and the large-scale
foreground filament) so-far identified toward this region. The narrow
absorption feature is similar to the one found toward low-mass protostars,
which is characteristic of the presence of a cold external envelope. The
far-infrared spectroscopic data were combined with existing ground-based
observations of 12CO, 13CO, CCH, CN, and C3H2 to characterize the 70 km/s
component. Using a non-LTE analysis of multiple transitions of NH3 and CN, we
estimated the density (n(H2) (1-5)x10^5 cm^-3) and temperature (10-30 K) for
this narrow feature. We used a gas-grain warm-up based chemical model with
physical parameters derived from the NH3 data to explain the observed
abundances of the different chemical species. We propose that the 70 km/s
narrow feature arises in a dense and cold clump that probably is undergoing
collapse to form a low-mass protostar, formed on the trailing side of the
high-velocity filament, which is thought to be interacting with the W51 main
cloud. While the fortuitous coincidence of the dense clump along the line of
sight with the continuum-bright W51e2 compact HII region has contributed to its
non-detection in the continuum images, this same attribute makes it an
appropriate source for absorption studies and in particular for ice studies of
star-forming regions.Comment: Accepted for publication in A&
First detection of [N II] 205 micrometer absorption in interstellar gas
We present high resolution [NII] 205 micrometer ^3P_1-^3P_0 spectra obtained
with Herschel-HIFI towards a small sample of far-infrared bright star forming
regions in the Galactic plane: W31C (G10.6-0.4), W49N (G43.2-0.1), W51
(G49.5-0.4), and G34.3+0.1. All sources display an emission line profile
associated directly with the HII regions themselves. For the first time we also
detect absorption of the [NII] 205 micrometer line by extended low-density
foreground material towards W31C and W49N over a wide range of velocities. We
attribute this absorption to the warm ionised medium (WIM) and find
N(N^+)\approx 1.5x10^17 cm^-2 towards both sources. This is in agreement with
recent Herschel-HIFI observations of [CII] 158 micrometer, also observed in
absorption in the same sight-lines, if \approx7-10 % of all C^+ ions exist in
the WIM on average. Using an abundance ratio of [N]/[H] = 6.76x10^-5 in the gas
phase we find that the mean electron and proton volume densities are ~0.1-0.3
cm^-3 assuming a WIM volume filling fraction of 0.1-0.4 with a corresponding
line-of-sight filling fraction of 0.46-0.74. A low density and a high WIM
filling fraction are also supported by RADEX modelling of the [NII] 205
micrometer absorption and emission together with visible emission lines
attributed mainly to the WIM. The detection of the 205 micrometer line in
absorption emphasises the importance of a high spectral resolution, and also
offers a new tool for investigation of the WIM.Comment: 7 pages, 4 figures, accepted for publication in Astronomy &
Astrophysics, 11 June 201
Arsenic trioxide down-regulates antiapoptotic genes and induces cell death in mycosis fungoides tumors in a mouse model
Background: Mycosis fungoides (MF) is the most frequent cutaneous T-cell lymphoma (CTCL). Arsenic trioxide (As2O3) has recently been shown to be effective against leukemias, so we studied whether As2O3 induces apoptosis of CTCL cells in vitro. We further investigated if As2O3 is effective in a MF mouse model. Material and methods: Annexin V/7-amino-actinomycin-D stainings were carried out to investigate if As2O3 induced apoptosis of CTCL cell lines. To study the underlying mechanisms, the effects of As2O3 on various transcription factors and apoptosis regulating proteins were analyzed by western blots, electrophoretic mobility shift assays and transcription factor enzyme-linked immunosorbent assays. The ability of As2O3 to induce tumor regression was investigated in a MF mouse model. Results: As2O3-induced apoptosis was paralleled by a reduction of the DNA-binding activities of transcription factors of the NFkB and signal transducer and activator of transcription gene families and reduced expression of the antiapoptotic proteins bcl-1, bcl-xL and mcl-1. Local injections of 200 μM As2O3 into tumors caused complete remissions in five of six mice and one partial remission. Conclusions: As2O3 induced apoptosis of CTCL cells by the down-regulation of transcription factors that stimulate the expression of antiapoptotic genes. Local injection of As2O3 into MF tumor-bearing mice resulted in tumor regressio
The chemistry of C3 & Carbon Chain Molecules in DR21(OH)
(Abridged) We have observed velocity resolved spectra of four ro-vibrational
far-infrared transitions of C3 between the vibrational ground state and the
low-energy nu2 bending mode at frequencies between 1654--1897 GHz using HIFI on
board Herschel, in DR21(OH), a high mass star forming region. Several
transitions of CCH and c-C3H2 have also been observed with HIFI and the IRAM
30m telescope. A gas and grain warm-up model was used to identify the primary
C3 forming reactions in DR21(OH). We have detected C3 in absorption in four
far-infrared transitions, P(4), P(10), Q(2) and Q(4). The continuum sources MM1
and MM2 in DR21(OH) though spatially unresolved, are sufficiently separated in
velocity to be identified in the C3 spectra. All C3 transitions are detected
from the embedded source MM2 and the surrounding envelope, whereas only Q(4) &
P(4) are detected toward the hot core MM1. The abundance of C3 in the envelope
and MM2 is \sim6x10^{-10} and \sim3x10^{-9} respectively. For CCH and c-C3H2 we
only detect emission from the envelope and MM1. The observed CCH, C3, and
c-C3H2 abundances are most consistent with a chemical model with
n(H2)\sim5x10^{6} cm^-3 post-warm-up dust temperature, T_max =30 K and a time
of \sim0.7-3 Myr. Post warm-up gas phase chemistry of CH4 released from the
grain at t\sim 0.2 Myr and lasting for 1 Myr can explain the observed C3
abundance in the envelope of DR21(OH) and no mechanism involving
photodestruction of PAH molecules is required. The chemistry in the envelope is
similar to the warm carbon chain chemistry (WCCC) found in lukewarm corinos.
The observed lower C3 abundance in MM1 as compared to MM2 and the envelope
could be indicative of destruction of C3 in the more evolved MM1. The timescale
for the chemistry derived for the envelope is consistent with the dynamical
timescale of 2 Myr derived for DR21(OH) in other studies.Comment: 11 Pages, 6 figures, accepted for publication in A&
Effects of oxidized lipids (4,5 (E)-epoxy-2(E)-heptenal and 4,5 (E)-epoxy-2 (E) -decenal) and lysine reaction products on zinc and calcium utilization: assays in Caco-2 cells
The influence of the presence of brown products from the reaction between two oxidized lipids (4,5 (E)-epoxy-2(E)-heptenal, EH, and 4,5 (E)-epoxy-2 (E)-decenal, ED) and lysine (EH-L and ED-L) on zinc and calcium utilization was studied, and compared with a fructosyl-lysine mixture (F-L). Assays were carried out in
Caco-2 cells grown in bicameral chambers. The Zn transported across the cell monolayer was significantly lower in the presence of the EH-L, ED-L and F-L samples, specially with EH-L. Significant decreases in Zn uptake were also observed, with no
differences between samples. However, calcium transport was not modified. Thus, the assayed lipid-aminoacid brown products seem to have negative effects on Zn availability, whereas Ca availability
appears to be unaffected.Se estudió la influencia de la presencia de productos obtenidos en la reacción de dos lípidos oxidados (4,5(E)-epoxy-2(E)- heptenal, EH, y 4,5(E)-epoxy-2(E)-decenal, ED) con el aminoácido lisina (EH-L y ED-L), sobre la absorción de zinc y calcio, comparándolos frente a una mezcla de fructosil-lisina (F-L). Los ensayos se realizaron con células Caco-2 sembradas en placas bicamerales. La adición de las muestras EH-L, ED-L y F-L al medio de cultivo supuso una reducción significativa en el Zn transportado a través de la monocapa de células, mucho más marcada ante la presencia de EH-L. También se redujo significativamente la captación celular de Zn, sin diferencias entre las distintas muestras ensayadas. Sin embargo, el transporte de Ca no se vio modificado. Por lo tanto, los productos pardos lípido-aminoacídicos ensayados parecen afectar negativamente la disponibilidad del Zn, sin tener efectos notables sobre la del Ca.Peer reviewe
What lies beneath: Hydra provides cnidarian perspectives into the evolution of FGFR docking proteins
Across the Bilateria, FGF/FGFR signaling is critical for normal development, and in both Drosophila and vertebrates, docking proteins are required to connect activated FGFRs with downstream pathways. While vertebrates use Frs2 to dock FGFR to the RAS/MAPK or PI3K pathways, the unrelated protein, downstream of FGFR (Dof/stumps/heartbroken), fulfills the corresponding function in Drosophila. To better understand the evolution of the signaling pathway downstream of FGFR, the available sequence databases were screened to identify Frs2, Dof, and other key pathway components in phyla that diverged early in animal evolution. While Frs2 homologues were detected only in members of the Bilateria, canonical Dof sequences (containing Dof, ankyrin, and SH2/SH3 domains) were present in cnidarians as well as bilaterians (but not in other animals or holozoans), correlating with the appearance of FGFR. Although these data suggested that Dof coupling might be ancestral, gene expression analysis in the cnidarian Hydra revealed that Dof is not upregulated in the zone of strong FGFRa and FGFRb expression at the bud base, where FGFR signaling controls detachment. In contrast, transcripts encoding other, known elements of FGFR signaling in Bilateria, namely the FGFR adaptors Grb2 and Crkl, which are acting downstream of Dof (and Frs2), as well as the guanyl nucleotide exchange factor Sos, and the tyrosine phosphatase Csw/Shp2, were strongly upregulated at the bud base. Our expression analysis, thus, identified transcriptional upregulation of known elements of FGFR signaling at the Hydra bud base indicating a highly conserved toolkit. Lack of transcriptional Dof upregulation raises the interesting question, whether Hydra FGFR signaling requires either of the docking proteins known from Bilateria
Connecting Berry's phase and the pumped charge in a Cooper pair pump
The properties of the tunnelling-charging Hamiltonian of a Cooper pair pump
are well understood in the regime of weak and intermediate Josephson coupling,
i.e. when . It is also known that
Berry's phase is related to the pumped charge induced by the adiabatical
variation of the eigenstates. We show explicitly that pumped charge in Cooper
pair pump can be understood as a partial derivative of Berry's phase with
respect to the phase difference across the array. The phase fluctuations
always present in real experiments can also be taken into account, although
only approximately. Thus the measurement of the pumped current gives reliable,
yet indirect, information on Berry's phase. As closing remarks, we give the
differential relation between Berry's phase and the pumped charge, and state
that the mathematical results are valid for any observable expressible as a
partial derivative of the Hamiltonian.Comment: 5 pages, 5 figures, RevTeX, Presentation has been clarifie
Jet formation and jet velocity fluctuations in a flue organ pipe
Flow visualization of the initial transient in a small recorderlike flue organ pipe is presented and the various stages of the jet formation are related to measurements of the acoustic response of the pipe. An initial acoustic signal, due to the unsteady volume flow of the jet, appears before the forming jet reaches the labium. This signal can easily be modeled using a low-frequency approximation. The initial trajectory of the jet makes a curve towards the exterior of the pipe. Under certain conditions, the jet may even, at first, miss the labium. This effect is related to the steepness of the pressure rise in the foot of the pipe. The initial impact of the jet with the labium appears to be a crucial factor in the triggering of the transient. Moving the labium towards the exterior of the pipe, using a steep pressure rise or putting ears around the mouth increase the chance that the jet will hit the labium. This initial impact is followed by an impulsive vortex shedding at the labium and subsequently a high-frequency varicoselike oscillation is observed on the jet. This oscillation is also observed without labium. After about three periods of the fundamental mode of the pipe, turbulence appears therefore destroying these coherent structures. Whereas the time dependency of the jet velocity dominates the first stage of the starting transient, the jet velocity fluctuations during steady-state result in a non-negligible damping. This loss mechanism is, for the fundamental mode of our experimental organ pipe, of the same order of magnitude as the radiation or visco-thermal damping.</p
Impaired sustained attention and executive dysfunction:bipolar disorder versus depression-specific markers of affective disorders
Objective - To identify neurocognitive measures that could be used as objective markers of bipolar disorder. Methods - We examined executive function, sustained attention and short-term memory as neurocognitive domains in 18 participants with bipolar disorder in euthymic state (Beuth), 14 in depressed state (Bdep), 20 with unipolar depression (Udep) and 28 healthy control participants (HC). We conducted four-group comparisons followed by relevant post hoc analyses. Results - Udep and Bdep, but not Beuth showed impaired executive function (p = 0.045 and p = 0.046, respectively). Both Bdep and Beuth, but not Udep, showed impaired sustained attention (p = 0.001 and p = 0.045, respectively). The four groups did not differ significantly on short-term memory. Impaired sustained attention and executive dysfunction were not associated with depression severity, duration of illness and age of illness onset. Only a small number of abnormal neurocognitive measures were associated with medication in Bdep and Beuth. Conclusion - Impaired sustained attention appears specific to bipolar disorder and present in both Beuth and Bdep; it may represent an objective marker of bipolar disorder. Executive dysfunction by contrast, appears to be present in Udep and Bdep and likely represents a marker of depression
Clinical Characteristics of Horses with Gastrointestinal Ruptures Revealed During Initial Diagnostic Evaluation: 149 Cases (1990-2002) (21-Nov-2003)
Abstract Common clinical findings associated with acute intestinal rupture include depression, sweating, reluctance to walk, tachycardia, fever, hemoconcentration with normoproteinemia, leukopenia, abnormal mucous membranes, elevated peritoneal fluid protein concentration, and abnormal peritoneal fluid color. Abdominal radiography and ultrasound can be useful diagnostic aids for identification of pneumoperitoneum associated with intestinal rupture
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