332 research outputs found
Physical Conditions in the Low-Ionization Component of Starburst Outflows: The Shape of Near-Ultraviolet and Optical Absorption-Line Troughs in Keck Spectra of ULIRGs
We analyze the physical conditions in the low-ionization component of
starburst outflows (in contrast to the high-ionization wind fluid observed in
X-rays), based on new Keck/LRIS spectroscopy of partially resolved absorption
troughs in near-ultraviolet and optical spectra of Ultraluminous Infrared
Galaxies. The large velocity width and blueshift present in seven, atomic
transitions indicate a macroscopic velocity gradient within the outflowing gas.
The \mgII 2796, 2803 (and \feII 2587, 2600) doublet lines in these data
constrains the gas kinematics better than the heavily blended \nad 5892, 98
doublet. The identical shape of the \mgII 2796 absorption troughs to that of
the normally weaker transition at 2803\AA requires both transitions be
optically thick at all outflow velocities. The fraction of the galactic
continuum covered by the outflow at each velocity therefore dictates the shape
of these absorption troughs. We suggest that the velocity offset of the deepest
part of the troughs, where the covering factor of low-ionization gas is near
unity, reflects the speed of a shell of swept-up, interstellar gas at the time
of blowout. In a spherical outflow, we show that the fragments of this shell
expand slowly relative to the geometrical dilution; and the covering fraction
of low-ionization gas decreases with increasing radius. Our measurement of a
covering factor that decreases with increasing velocity can therefore be
interpreted as evidence that the low-ionization outflow is accelerating. We
also present measurements of C_f(v) in 4 species, place an upper limit of 3000
cm3 on the density of the outflowing gas, and discuss lower limits on the mass
outflow rate.Comment: 28 pages, 10 figures, to appear in Ap
H-alpha Imaging with HST+NICMOS of An Elusive Damped Ly-alpha Cloud at z=0.6
Despite previous intensive ground-based imaging and spectroscopic campaigns
and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts
the damped Ly-alpha system along this line-of-sight has eluded detection. We
present a deep narrow-band H-alpha image of the field of this z=0.656 damped
Ly-alpha absorber, obtained through the F108N filter of NICMOS 1 onboard the
Hubble Space Telescope. The goal of this project was to detect any H-alpha
emission 10 times closer than previous studies to unveil the damped absorber.
We do not detect H-alpha emission between 0.05'' and 6'' (0.24 and 30
kpc) from the QSO, with a 3-sigma flux limit of
erg/s/cm^2 for an unresolved source, corresponding to a star formation rate
(SFR) of M_sun/yr. This leads to a 3-sigma upper limit of 0.15
M_sun/yr/kpc^2 on the SFR density, or a maximum SFR of 1.87 M_sun/yr assuming a
disk of 4 kpc in diameter. This result adds to the number of low redshift
damped Ly-alpha absorbers that are not associated with the central regions of
Milky-Way-like disks. Damped Ly-alpha absorption can arise from high density
concentrations in a variety of galactic environments including some that,
despite their high local HI densities, are not conducive to widespread star
formation.Comment: 18 pages, 3 figures. Replaced to match published version in ApJ, 550,
585 (Apr 1 2001
Measuring the halo mass of MgII absorbers from their cross-correlation with Luminous Red Galaxies
We study the cross-correlation between 716 MgII quasar absorption systems and
about 100,000 Luminous Red Galaxies (LRGs) selected from the Sloan Digital Sky
Survey Data Release 3 in the redshift range 0.4<z<0.8. The MgII systems were
selected to have 2796 & 2803 rest-frame equivalent widths greater than 1.0 \AA
and identifications confirmed by the FeII 2600 or MgI 2852 lines. Over
co-moving scales 0.2--13/h Mpc, the MgII--LRG cross-correlation has an
amplitude 0.69+/-0.09 times that of the LRG--LRG auto-correlation. Since LRGs
have halo-masses of 10^{13} \msun, this strong cross-correlation implies that
the absorber host-galaxies have halo-masses 1--2 times 10^{12} \msun.Comment: 3 pages, 2 figures, to appear in IAU 199 conf. proc.: "Probing
Galaxies through Quasar Absorption Lines," eds. Williams, Shu, Menard; minor
changes to match the edited versio
Measuring the Halo Mass of z=3 Damped Ly-alpha Absorbers from the Absorber-Galaxy Cross-correlation
[Abridged] We test the reliability of a method to measure the mean halo mass
of Damped Ly-alpha absorbers (DLAs). The method is based on measuring the ratio
of the cross-correlation between DLAs and galaxies to the auto-correlation of
the galaxies themselves (), which is (in linear theory)
the ratio of their bias factor. This is shown to be true irrespective of the
galaxy redshift distribution, provided that one uses the same galaxies for the
two correlation functions. The method is applicable to all redshifts. Here, we
focus on z=3 DLAs and we demonstrate that the method robustly constrains the
mean DLA halo mass using smoothed particle hydrodynamics (SPH) cosmological
simulations. If we use the bias formalism of Mo & White with the DLA and galaxy
mass distributions of these simulations, we predict a bias ratio of 0.771.
Direct measurement from the simulations of st yields a
ratio of 0.73+/-0.08, in excellent agreement with that prediction.
Equivalently, inverting the measured correlation ratio to infer a mean DLA halo
mass yields (log. averaging, in solar units) =11.13+/-013, in
excellent agreement with the true value in the simulations: 11.16. The cross-
correlation method thus appears to yield a robust estimate of the average host
halo mass even though the DLAs and the galaxies occupy a broad mass spectrum of
halos, and massive halos contain multiple galaxies with DLAs. We show that the
inferred mean DLA halo mass is independent of the galaxy sub-sample used, i.e.
the cross-correlation technique is also reliable. Our results imply that the
cross-correlation length between DLAs and LBGs is predicted to be, at most,
2.85 Mpc. Future observations will soon distinguish models in which DLAs are in
low mass halos from those in which DLAs are in massive halos.Comment: 15 pages, 7 figures, to be published in ApJ 2005 July 20th (Full
resolution of Fig.2 at
http://www.mpe.mpg.de/~nbouche/papers/Xcorr/f2-orig.eps); minor changes to
match the published tex
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The Effect of Inspector Group Size and Familiarity on Enforcement and Deterrence
Bouche Charles-François, Buzot François-Nicolas, Folleville Antoine-Charles, marquis de, Camus Armand Gaston, Rewbell Jean François. Discussion du projet de dĂ©cret concernant la liquidation des crĂ©ances mises Ă la charge de la nation par arrĂȘts du conseil, lors de la sĂ©ance du 25 avril 1791. In: Archives Parlementaires de 1787 Ă 1860 - PremiĂšre sĂ©rie (1787-1799) Tome XXV - Du 13 avril 1791 au 11 mai 1791. Paris : Librairie Administrative P. Dupont, 1886. p. 334
Chronic delivery of antibody fragments using immunoisolated cell implants as a passive vaccination tool
Background: Monoclonal antibodies and antibody fragments are powerful biotherapeutics for various debilitating diseases. However, high production costs, functional limitations such as inadequate pharmacokinetics and tissue accessibility are the current principal disadvantages for broadening their use in clinic. Methodology and Principal Findings: We report a novel method for the long-term delivery of antibody fragments. We designed an allogenous immunoisolated implant consisting of polymer encapsulated myoblasts engineered to chronically release scFv antibodies targeted against the N-terminus of the AÎČ peptide. Following a 6-month intracerebral therapy we observed a significant reduction of the production and aggregation of the AÎČ peptide in the APP23 transgenic mouse model of Alzheimer's disease. In addition, functional assessment showed prevention of behavioral deficits related to anxiety and memory traits. Conclusions and Significance : The chronic local release of antibodies using immunoisolated polymer cell implants represents an alternative passive vaccination strategy in Alzheimer's disease. This novel technique could potentially benefit other diseases presently treated by local and systemic antibody administration
A randomized, phase III trial of capecitabine plus bevacizumab (Cape-Bev) versus capecitabine plus irinotecan plus bevacizumab (CAPIRI-Bev) in first-line treatment of metastatic colorectal cancer: The AIO KRK 0110 Trial/ML22011 Trial
<p>Abstract</p> <p>Background</p> <p>Several randomized trials have indicated that combination chemotherapy applied in metastatic colorectal cancer (mCRC) does not significantly improve overall survival when compared to the sequential use of cytotoxic agents (CAIRO, MRC Focus, FFCD 2000-05). The present study investigates the question whether this statement holds true also for bevacizumab-based first-line treatment including escalation- and de-escalation strategies.</p> <p>Methods/Design</p> <p>The AIO KRK 0110/ML22011 trial is a two-arm, multicenter, open-label randomized phase III trial comparing the efficacy and safety of capecitabine plus bevacizumab (Cape-Bev) versus capecitabine plus irinotecan plus bevacizumab (CAPIRI-Bev) in the first-line treatment of metastatic colorectal cancer. Patients with unresectable metastatic colorectal cancer, Eastern Cooperative Oncology Group (ECOG) performance status 0-1, will be assigned in a 1:1 ratio to receive either capecitabine 1250 mg/m<sup>2 </sup>bid for 14d (d1-14) plus bevacizumab 7.5 mg/kg (d1) q3w (Arm A) or capecitabine 800 mg/m<sup>2 </sup>BID for 14d (d1-14), irinotecan 200 mg/m<sup>2 </sup>(d1) and bevacizumab 7.5 mg/kg (d1) q3w (Arm B). Patients included into this trial are required to consent to the analysis of tumour tissue and blood for translational investigations. In Arm A, treatment escalation from Cape-Bev to CAPIRI-Bev is recommended in case of progressive disease (PD). In Arm B, de-escalation from CAPIRI-Bev to Cape-Bev is possible after 6 months of treatment or in case of irinotecan-associated toxicity. Re-escalation to CAPIRI-Bev after PD is possible. The primary endpoint is time to failure of strategy (TFS). Secondary endpoints are overall response rate (ORR), overall survival, progression-free survival, safety and quality of life.</p> <p>Conclusion</p> <p>The AIO KRK 0110 trial is designed for patients with disseminated, but asymptomatic mCRC who are not potential candidates for surgical resection of metastasis. Two bevacizumab-based strategies are compared: one starting as single-agent chemotherapy (Cape-Bev) allowing escalation to CAPIRI-Bev and another starting with combination chemotherapy (CAPIRI-Bev) and allowing de-escalation to Cape-Bev and subsequent re-escalation if necessary.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier <a href="http://www.clinicaltrials.gov/ct2/show/NCT01249638">NCT01249638</a></p> <p>EudraCT-No.: 2009-013099-38</p
Chronic Delivery of Antibody Fragments Using Immunoisolated Cell Implants as a Passive Vaccination Tool
BACKGROUND: Monoclonal antibodies and antibody fragments are powerful biotherapeutics for various debilitating diseases. However, high production costs, functional limitations such as inadequate pharmacokinetics and tissue accessibility are the current principal disadvantages for broadening their use in clinic.
METHODOLOGY AND PRINCIPAL FINDINGS: We report a novel method for the long-term delivery of antibody fragments. We designed an allogenous immunoisolated implant consisting of polymer encapsulated myoblasts engineered to chronically release scFv antibodies targeted against the N-terminus of the AÎČ peptide. Following a 6-month intracerebral therapy we observed a significant reduction of the production and aggregation of the AÎČ peptide in the APP23 transgenic mouse model of Alzheimer's disease. In addition, functional assessment showed prevention of behavioral deficits related to anxiety and memory traits.
CONCLUSIONS AND SIGNIFICANCE: The chronic local release of antibodies using immunoisolated polymer cell implants represents an alternative passive vaccination strategy in Alzheimer's disease. This novel technique could potentially benefit other diseases presently treated by local and systemic antibody administration
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