297,771 research outputs found
Polymeric alkali fullerides are stable in air
Infrared transmission, electron spin resonance, and X-ray diffraction
measurements show unambiguously that RbC and KC are stable in
air, in contrast to RbC which decomposes rapidly upon exposure.
The specimens studied transform into pure C and other byproducts when
heated above 100\dd C, approximately the temperature of the orthorhombic-fcc
phase transition. The stability of these compounds raises the possibility of
applying them as protective layers for the superconducting fullerides.Comment: Scheduled for publication in Appl. Phys. Lett. 66, 20 Feb. 1995,
typeset in REVTEX v3.0 in LaTeX. Postscript file including all figures is
available on WWW http://insti.physics.sunysb.edu/~mmartin/ under my list of
publications, or will be e-mailed by request
Pharmacoeconomic analysis of adjuvant oral capecitabine vs intravenous 5-FU/LV in Dukes' C colon cancer: the X-ACT trial
Oral capecitabine (Xeloda<sup>®</sup>) is an effective drug with favourable safety in adjuvant and metastatic colorectal cancer. Oxaliplatin-based therapy is becoming standard for Dukes' C colon cancer in patients suitable for combination therapy, but is not yet approved by the UK National Institute for Health and Clinical Excellence (NICE) in the adjuvant setting. Adjuvant capecitabine is at least as effective as 5-fluorouracil/leucovorin (5-FU/LV), with significant superiority in relapse-free survival and a trend towards improved disease-free and overall survival. We assessed the cost-effectiveness of adjuvant capecitabine from payer (UK National Health Service (NHS)) and societal perspectives. We used clinical trial data and published sources to estimate incremental direct and societal costs and gains in quality-adjusted life months (QALMs). Acquisition costs were higher for capecitabine than 5-FU/LV, but higher 5-FU/LV administration costs resulted in 57% lower chemotherapy costs for capecitabine. Capecitabine vs 5-FU/LV-associated adverse events required fewer medications and hospitalisations (cost savings ÂŁ3653). Societal costs, including patient travel/time costs, were reduced by >75% with capecitabine vs 5-FU/LV (cost savings ÂŁ1318), with lifetime gain in QALMs of 9 months. Medical resource utilisation is significantly decreased with capecitabine vs 5-FU/LV, with cost savings to the NHS and society. Capecitabine is also projected to increase life expectancy vs 5-FU/LV. Cost savings and better outcomes make capecitabine a preferred adjuvant therapy for Dukes' C colon cancer. This pharmacoeconomic analysis strongly supports replacing 5-FU/LV with capecitabine in the adjuvant treatment of colon cancer in the UK
X-ray emission from an FU Ori star in early outburst: HBC 722
Aims: We conducted the first X-ray observations of the newly erupting FU
Ori-type outburst in HBC 722 (V2493 Cyg) with the aim to characterize its X-ray
behavior and near-stellar environment during early outburst. Methods: We used
data from the XMM-Newton and Chandra X-ray observatories to measure X-ray
source temperatures and luminosities as well as the gas column densities along
the line of sight toward the source. Results: We report a Chandra X-ray
detection of HBC 722 with an X-ray luminosity of LX ~ 4E30 erg s-1. The gas
column density exceeds values expected from optical extinction and standard
gas-to-dust ratios. We conclude that dust-free gas masses are present around
the star, such as strong winds launched from the inner disk, or massive
accretion columns. A tentative detection obtained by XMM-Newton two years
earlier after an initial optical peak revealed a fainter X-ray source with only
weak absorption.Comment: Accepted for Astronomy & Astrophysics Letters on September 17, 201
Reproductive Isolation: Evidence that Ascobolus stercorarius and Ascobolus furfuraceus are two species, not one
Strains obtained from the germination of 30-40 year old ascospores from seven stocks of the heterothallicAscobolus stercorarius - furfuraceous complex were mated in all combinations. All st X st and fu X fu pairings were fertile (ascospores) whereas all st X fu pairings were sterile (no ascospores). Based on this reproductive isolation between st and fu strains I conclude that the complex consists of two species. The block that segregated the two species is probably some stage in the establishment of the dikaryotic phase in ascogenous hyphae. One hypothesis is that this block is at the stage of nuclear recognition
Mouse Suppressor of fused is a negative regulator of Sonic hedgehog signaling and alters the subcellular distribution of Gli1
AbstractThe Hedgehog (Hh) signaling pathway has critical functions during embryogenesis of both invertebrate and vertebrate species [1]; defects in this pathway in humans can cause developmental disorders as well as neoplasia [2]. Although the Gli1, Gli2, and Gli3 zinc finger proteins are known to be effectors of Hh signaling in vertebrates, the mechanisms regulating activity of these transcription factors remain poorly understood [3,4]. In Drosophila, activity of the Gli homolog Cubitus interruptus (Ci) is likely to be modulated by its interaction with a cytoplasmic complex containing several other proteins [5,6], including Costal2, Fused (Fu), and Suppressor of fused (Su(fu)), the last of which has been shown to interact directly with Ci [7]. We have cloned mouse Suppressor of fused (mSu(fu)) and detected its 4.5 kb transcript throughout embryogenesis and in several adult tissues. In cultured cells, mSu(fu) overexpression inhibited transcriptional activation mediated by Sonic hedgehog (Shh), Gli1 and Gli2. Co-immunoprecipitation of epitope-tagged proteins indicated that mSu(fu) interacts with Gli1, Gli2, and Gli3, and that the inhibitory effects of mSu(fu) on Gli1's transcriptional activity were mediated through interactions with both amino- and carboxy-terminal regions of Gli1. Gli1 was localized primarily to the nucleus of both HeLa cells and the Shh-responsive cell line MNS-70; co-expression with mSu(fu) resulted in a striking increase in cytoplasmic Gli1 immunostaining. Our findings indicate that mSu(fu) can function as a negative regulator of Shh signaling and suggest that this effect is mediated by interaction with Gli transcription factors
Adsorption of 5-Fluorouracil on Au(111) and Cu(111) surfaces
The adsorption of 5-Fluorouracil (5FU) on Au(111) and Cu(111) surfaces as a function of molecular coverage and temperature has been studied, using x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. The nature of 5-Fluorouracil bonding with the two substrates is remarkably different. The Cu substrate forms a chemisorbed complex with 5-FU while the Au substrate shows only physisorption. NEXAFS data at the C, N and O K-edge show a strong angular dependence, indicating that 5-FU lies nearly parallel on the inert Au(111) surface, and at a steep angle on the Cu(111) surface. 5-FU is a biomolecule used for cancer treatment and the results are relevant for those using metal surfaces to prepare 5-FU for applications such as drug delivery.The adsorption of 5-Fluorouracil (5FU) on Au(111) and Cu(111) surfaces as a function of molecular coverage and temperature has been studied, using x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. The nature of 5-Fluorouracil bonding with the two substrates is remarkably different. The Cu substrate forms a chemisorbed complex with 5-FU while the Au substrate shows only physisorption. NEXAFS data at the C, N and O K-edge show a strong angular dependence, indicating that 5-FU lies nearly parallel on the inert Au(111) surface, and at a steep angle on the Cu(111) surface. 5-FU is a biomolecule used for cancer treatment and the results are relevant for those using metal surfaces to prepare 5-FU for applications such as drug delivery
Spectral Changes in the Hyperluminous Pulsar in NGC 5907 as a Function of Super-Orbital Phase
We present broad-band, multi-epoch X-ray spectroscopy of the pulsating
ultra-luminous X-ray source (ULX) in NGC 5907. Simultaneous XMM-Newton and
NuSTAR data from 2014 are best described by a multi-color black-body model with
a temperature gradient as a function of accretion disk radius significantly
flatter than expected for a standard thin accretion disk (T(r) ~ r^{-p}, with
p=0.608^{+0.014}_{-0.012}). Additionally, we detect a hard power-law tail at
energies above 10 keV, which we interpret as being due to Comptonization. We
compare this observation to archival XMM-Newton, Chandra, and NuSTAR data from
2003, 2012, and 2013, and investigate possible spectral changes as a function
of phase over the 78d super-orbital period of this source. We find that
observations taken around phases 0.3-0.4 show very similar temperature
profiles, even though the observed flux varies significantly, while one
observation taken around phase 0 has a significantly steeper profile. We
discuss these findings in light of the recent discovery that the compact object
is a neutron star and show that precession of the accretion disk or the neutron
star can self-consistently explain most observed phenomena.Comment: 7 pages, 5 figures, submitted to ApJ; comments welcom
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