249 research outputs found
The Del1 deposition domain can immobilize 3α-hydroxysteroid dehydrogenase in the extracellular matrix without interfering with enzymatic activity
Developing methods that result in targeting of therapeutic molecules in gene therapies to target tissues has importance, as targeting can increase efficacy and decrease off target-side-effects. Work from my laboratory previously showed that the extracellular matrix protein Del1 is organized in the extracellular matrix (ECM) via the Del1 deposition domain (DDD). In this work, a fusion protein with DDD was made to assay the ability to immobilize an enzyme without disrupting enzymatic function. A prostatic cancer-derived cell line LNCap that grows in an androgen-dependent manner was used with 3α-hydroxysteroid dehydrogenase (3 αHD), which catalyzes dihydrotestosterone (DHT). Plasmids encoding a 3αHD:DDD fusion were generated and transfected into cultured cells. The effects of 3αHD immobilized in the ECM by the DDD were evaluated by monitoring growth of LNCap cells and DHT concentrations. It was demonstrated that the DDD could immobilize an enzyme in the ECM without interfering with function
EDIL3 (EGF-Like Repeats And Discoidin I-Like Domains 3)
Review on EDIL3, with data on DNA/RNA, on the protein encoded and where the gene is implicated
Galactic chemical evolution : Carbon through zinc
Copyright © 2006. The American Astronomical Society. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at https://doi.org/10.1086/508914We calculate the evolution of heavy-element abundances from C to Zn in the solar neighborhood, adopting our new nucleosynthesis yields. Our yields are calculated for wide ranges of metallicity (Z = 0-Z circle dot) and the explosion energy (normal supernovae and hypernovae), based on the light-curve and spectra fitting of individual supernovae. The elemental abundance ratios are in good agreement with observations. Among the alpha-elements, O, Mg, Si, S, and Ca show a plateau at [Fe/H] <= -1, while Ti is underabundant overall. The observed abundance of Zn ([Zn/Fe] similar to 0) can be explained only by the high-energy explosion models, as it requires a large contribution of hypernovae. The observed decrease in the odd-Z elements (Na, Al, and Cu) toward low [Fe/H] is reproduced by the metallicity effect on nucleosynthesis. The iron-peak elements (Cr, Mn, Co, and Ni) are consistent with the observed mean values at -2.5 less than or similar to [Fe/H] less than or similar to -1, and the observed trend at the lower metallicity can be explained by the energy effect. We also show the abundance ratios and the metallicity distribution functions of the Galactic bulge, halo, and thick disk. Our results suggest that the formation timescale of the thick disk is similar to 1-3 Gyr.Peer reviewe
Chemical Abundances in the Secondary Star of the Black Hole Binary V4641 Sagittarii (SAX J1819.3-2525)
We report on detailed spectroscopic studies performed for the secondary star
in the black hole binary (micro-quasar) V4641 Sgr in order to examine its
surface chemical composition and to see if its surface shows any signature of
pollution by ejecta from a supernova explosion. High-resolution spectra of
V4641 Sgr observed in the quiescent state in the blue-visual region are
compared with those of the two bright well-studied B9 stars (14 Cyg and
Cap) observed with the same instrument. The effective temperature of V4641 Sgr
(10500 200 K) is estimated from the strengths of He~{\sc i} lines, while
its rotational velocity, sin (95 10 km s), is
estimated from the profile of the Mg~{\sc ii} line at 4481 \AA. We obtain
abundances of 10 elements and find definite over-abundances of N (by 0.8 dex or
more) and Na (by 0.8 dex) in V4641 Sgr. From line-by-line comparisons of eight
other elements (C, O, Mg, Al, Si, Ti, Cr, and Fe) between V4641 Sgr and the two
reference stars, we conclude that there is no apparent difference in the
abundances of these elements between V4641 Sgr and the two normal late B-type
stars, which have been reported to have solar abundances. An evolutionary model
of a massive close binary system has been constructed to explain the abundances
observed in V4641 Sgr. The model suggests that the progenitor of the black hole
forming supernova was as massive as ~ 35 Msun on the main-sequence and, after
becoming a ~ 10 Msun He star, underwent "dark" explosion which ejected only N
and Na-rich outer layer of the He star without radioactive Ni.Comment: 13 pages, 14 figures. Accepted for publication in the PASJ:
Publications of the Astronomical Society of Japa
The Aspherical Properties of the Energetic Type Ic SN 2002ap as Inferred from its Nebular Spectra
The nebular spectra of the broad-lined, SN 1998bw-like Type Ic SN 2002ap are
studied by means of synthetic spectra. Two different modelling techniques are
employed. In one technique, the SN ejecta are treated as a single zone, while
in the other a density and abundance distribution in velocity is used from an
explosion model. In both cases, heating caused by gamma-ray and positron
deposition is computed (in the latter case using a Monte Carlo technique to
describe the propagation of gamma-rays and positrons), as is cooling via
forbidden-line emission. The results are compared, and although general
agreement is found, the stratified models are shown to reproduce the observed
line profiles much more accurately than the single-zone model. The explosion
produced ~ 0.1 Msun of 56Ni. The distribution in velocity of the various
elements is in agreement with that obtained from the early-time models, which
indicated an ejected mass of ~ 2.5 Msun with a kinetic energy of 4 x 10^{51}
erg. Nebular spectroscopy confirms that most of the ejected mass (~ 1.2 Msun)
was oxygen. The presence of an oxygen-rich inner core, combined with that of
56Ni at high velocities as deduced from early-time models, suggests that the
explosion was asymmetric, especially in the inner part.Comment: 24 pages, 6 figures, 2 Tables. Accepted by the Astrophysical Journa
C, S, Zn and Cu abundances in planet-harbouring stars
We present a detailed and uniform study of C, S, Zn and Cu abundances in a
large set of planet host stars, as well as in a homogeneous comparison sample
of solar-type dwarfs with no known planetary-mass companions. Carbon abundances
were derived by {EW} measurement of two C I optical lines, while spectral
syntheses were performed for S, Zn and Cu. We investigated possible differences
in the behaviours of the volatiles C, S and Zn and in the refractory Cu in
targets with and without known planets in order to check possible anomalies due
to the presence of planets. We found that the abundance distributions in stars
with exoplanets are the high [Fe/H] extensions of the trends traced by the
comparison sample. All volatile elements we studied show [X/Fe] trends
decreasing with [Fe/H] in the metallicity range -0.8<[Fe/H]<0.5, with
significantly negative slopes of -0.39+-0.04 and -0.35+-0.04 for C and S,
respectively. A comparison of our abundances with those available in the
literature shows good agreement in most cases.Comment: 28 pages, 13 figures, accepted for publication in A&
Evidence for a companion to BM Gem, a silicate carbon star
Balmer and Paschen continuum emission as well as Balmer series lines of P
Cygni-type profile from H_gamma through H_23 are revealed in the violet spectra
of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell
(`silicate carbon star') observed with the high dispersion spectrograph (HDS)
on the Subaru telescope. The blue-shifted absorption in the Balmer lines
indicates the presence of an outflow, the line of sight velocity of which is at
least 400 km s^-1, which is the highest outflow velocity observed to date in a
carbon star. We argue that the observed unusual features in BM Gem are strong
evidence for the presence of a companion, which should form an accretion disk
that gives rise to both an ionized gas region and a high velocity, variable
outflow. The estimated luminosity of ~0.2 (0.03-0.6) L_sun for the ionized gas
can be maintained by a mass accretion rate to a dwarf companion of ~10^-8 M_sun
yr^-1, while ~10^-10 M_sun yr^-1 is sufficient for accretion to a white dwarf
companion. These accretion rates are feasible for some detached binary
configurations on the basis of the Bond-Hoyle type accretion process. We
concluded that the carbon star BM Gem is in a detached binary system with a
companion of low mass and low luminosity. However, we are unable to determine
whether this companion object is a dwarf or a white dwarf. The upper limits for
binary separation are 210 AU and 930 AU for a dwarf and a white dwarf,
respectively. We also note that the observed features of BM Gem mimic those of
Mira (omi Cet), which may suggest actual similarities in their binary
configurations and circumstellar structures.Comment: 11 pages, 2 figures, 1 table, accepted for publication in Ap
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