20 research outputs found
The Use of Prosthetic Stents in Tracheobronchial, Gastrointestinal, and Genitourinary Diseases
The concept of using a stent to maintain patency of a lumen is not new. As early as 1969, stents were
being investigated in the peripheral arterial system as a means of preventing restenosis after dilatation
by balloon angioplasty (Dotter, 1969). Since then, numerous reports have demonstrated the use
of stents in both the peripheral and coronary artery systems (Maass et al., 1982; Dotter et al., 1983;
Wright et al., 1985; Palmaz et al., 1987). Concomitant with the investigation of expandable endovascular
metal prosthesis has been the development of prosthetic devices for management of tracheobronchial,
gastrointestinal, and genitourinary diseases. We will review the use of endoscopically
placed prosthetic devices in the management of diseases affecting these systems
A magnetically-driven piston pump for ultra-clean applications
A magnetically driven piston pump for xenon gas recirculation is presented.
The pump is designed to satisfy extreme purity and containment requirements, as
is appropriate for the recirculation of isotopically enriched xenon through the
purification system and large liquid xenon TPC of EXO-200. The pump, using
sprung polymer gaskets, is capable of pumping more than 16 standard liters per
minute (SLPM) of xenon gas with 750 torr differential pressure.Comment: 6 pages, 5 figure
Evidence for Type Ia Supernova Diversity from Ultraviolet Observations with the Hubble Space Telescope
We present ultraviolet (UV) spectroscopy and photometry of four Type Ia
supernovae (SNe 2004dt, 2004ef, 2005M, and 2005cf) obtained with the UV prism
of the Advanced Camera for Surveys on the Hubble Space Telescope. This dataset
provides unique spectral time series down to 2000 Angstrom. Significant
diversity is seen in the near maximum-light spectra (~ 2000--3500 Angstrom) for
this small sample. The corresponding photometric data, together with archival
data from Swift Ultraviolet/Optical Telescope observations, provide further
evidence of increased dispersion in the UV emission with respect to the
optical. The peak luminosities measured in uvw1/F250W are found to correlate
with the B-band light-curve shape parameter dm15(B), but with much larger
scatter relative to the correlation in the broad-band B band (e.g., ~0.4 mag
versus ~0.2 mag for those with 0.8 < dm15 < 1.7 mag). SN 2004dt is found as an
outlier of this correlation (at > 3 sigma), being brighter than normal SNe Ia
such as SN 2005cf by ~0.9 mag and ~2.0 mag in the uvw1/F250W and uvm2/F220W
filters, respectively. We show that different progenitor metallicity or
line-expansion velocities alone cannot explain such a large discrepancy.
Viewing-angle effects, such as due to an asymmetric explosion, may have a
significant influence on the flux emitted in the UV region. Detailed modeling
is needed to disentangle and quantify the above effects.Comment: 17 pages, 13 figures, accepted by Ap