1,747 research outputs found
A WXW Motif Is Required for the Anticancer Activity of the TAT-RasGAP317-326 Peptide.
TAT-RasGAP317-326, a cell-permeable 10-amino acid-long peptide derived from the N2 fragment of p120 Ras GTPase-activating protein (RasGAP), sensitizes tumor cells to apoptosis induced by various anticancer therapies. This RasGAP-derived peptide, by targeting the deleted in liver cancer-1 (DLC1) tumor suppressor, also hampers cell migration and invasion by promoting cell adherence and by inhibiting cell movement. Here, we systematically investigated the role of each amino acid within the RasGAP317-326 sequence for the anticancer activities of TAT-RasGAP317-326. We report here that the first three amino acids of this sequence, tryptophan, methionine, and tryptophan (WMW), are necessary and sufficient to sensitize cancer cells to cisplatin-induced apoptosis and to reduce cell migration. The WMW motif was found to be critical for the binding of fragment N2 to DLC1. These results define the interaction mode between the active anticancer sequence of RasGAP and DLC1. This knowledge will facilitate the design of small molecules bearing the tumor-sensitizing and antimetastatic activities of TAT-RasGAP317-326
Magnetoplasmon excitations in arrays of circular and noncircular quantum dots
We have investigated the magnetoplasmon excitations in arrays of circular and
noncircular quantum dots within the Thomas-Fermi-Dirac-von Weizs\"acker
approximation. Deviations from the ideal collective excitations of isolated
parabolically confined electrons arise from local perturbations of the
confining potential as well as interdot Coulomb interactions. The latter are
unimportant unless the interdot separations are of the order of the size of the
dots. Local perturbations such as radial anharmonicity and noncircular symmetry
lead to clear signatures of the violation of the generalized Kohn theorem. In
particular, the reduction of the local symmetry from SO(2) to results in
a resonant coupling of different modes and an observable anticrossing behaviour
in the power absorption spectrum. Our results are in good agreement with recent
far-infrared (FIR) transmission experiments.Comment: 25 pages, 6 figures, typeset in RevTe
The development and acceptability of an educational and training intervention for recruiters to neonatal trials : the TRAIN project
Peer reviewedPublisher PD
A Search for Propylene Oxide and Glycine in Sagittarius B2 (LMH) and Orion
We have used the Mopra Telescope to search for glycine and the simple chiral
molecule propylene oxide in the Sgr B2 (LMH) and Orion KL, in the 3-mm band. We
have not detected either species, but have been able to put sensitive upper
limits on the abundances of both molecules. The 3-sigma upper limits derived
for glycine conformer I are 3.7 x 10^{14} cm^{-2} in both Orion-KL and Sgr B2
(LMH), comparable to the reported detections of conformer I by Kuan et al.
However, as our values are 3-sigma upper limits rather than detections we
conclude that this weighs against confirming the detection of Kuan et al. We
find upper limits for the glycine II column density of 7.7 x 10^{12} cm^{-2} in
both Orion-KL and Sgr B2 (LMH), in agreement with the results of Combes et al.
The results presented here show that glycine conformer II is not present in the
extended gas at the levels detected by Kuan et al. for conformer I. Our ATCA
results (Jones et al.) have ruled out the detection of glycine (both conformers
I and II) in the compact hot core of the LMH at the levels reported, so we
conclude that it is unlikely that Kuan et al. have detected glycine in either
Sgr B2 or Orion-KL. We find upper limits for propylene oxide abundance of 3.0 x
10^{14} cm^{-2} in Orion-KL and 6.7 x 10^{14} cm^{-2} in Sgr B2 (LMH). We have
detected fourteen features in Sgr B2 and four features in Orion-KL which have
not previously been reported in the ISM, but have not be able to plausibly
assign these transitions to any carrier.Comment: 12 pages, 3 figures. Accepted by MNRAS 12th January 200
Microscopic description of the surface dipole plasmon in large Na_N clusters (950 < N < 12050)
Fully microscopic RPA/LDA calculations of the dipole plasmon for very large
neutral and charged sodium clusters, Na_N^Z+, in the size range 950
< N < 12050 are presented for the first time. 60 different sizes are
considered altogether, which allows for an in-depth investigation of the
asymptotic behavior of both the width and the position of the plasmon.Comment: Latex/Revtex, 4 pages with 4 Postscript figures, accepted for
publication in Physical Review
Implementation of the Combined--Nonlinear Condensation Transformation
We discuss several applications of the recently proposed combined
nonlinear-condensation transformation (CNCT) for the evaluation of slowly
convergent, nonalternating series. These include certain statistical
distributions which are of importance in linguistics, statistical-mechanics
theory, and biophysics (statistical analysis of DNA sequences). We also discuss
applications of the transformation in experimental mathematics, and we briefly
expand on further applications in theoretical physics. Finally, we discuss a
related Mathematica program for the computation of Lerch's transcendent.Comment: 23 pages, 1 table, 1 figure (Comput. Phys. Commun., in press
Sharp and Smooth Boundaries of Quantum Hall Liquids
We study the transition between sharp and smooth density distributions at the
edges of Quantum Hall Liquids in the presence of interactions. We find that,
for strong confining potentials, the edge of a liquid is described by
the Fermi Liquid theory, even in the presence of interactions, a
consequence of the chiral nature of the system. When the edge confining
potential is decreased beyond a point, the edge undergoes a reconstruction and
electrons start to deposit a distance magnetic lengths away from the
initial QH Liquid. Within the Hartree-Fock approximation, a new pair of
branches of gapless edge excitations is generated after the transition. We show
that the transition is controlled by the balance between a long-ranged
repulsive Hartree term and a short-ranged attractive exchange term. Such
transition also occurs for Quantum Dots in the Quantum Hall Regime, and should
be observable in resonant tunneling experiments. Electron tunneling into the
reconstructed edge is also discussed.Comment: 28 pages, REVTeX 3.0, 18 figures available upon request,
cond-mat/yymmnn
Reasons for and consequences of missed appointments in general practice in the UK: questionnaire survey and prospective review of medical records
Background
Missed appointments are a common occurrence in primary care in the UK, yet little is known about the reasons for them, or the consequences of missing an appointment. This paper aims to determine the reasons for missed appointments and whether patients who miss an appointment subsequently consult their general practitioner (GP). Secondary aims are to compare psychological morbidity, and the previous appointments with GPs between subjects and a comparison group.
Methods
Postal questionnaire survey and prospective medical notes review of adult patients missing an appointment and the comparison group who attended appointments over a three week period in seven general practices in West Yorkshire.
Results
Of the 386 who missed appointments 122 (32%) responded. Of the 386 in the comparison group 223 (58%) responded, resulting in 23 case-control matched pairs with complete data collection. Over 40% of individuals who missed an appointment and participated said that they forgot the appointment and a quarter said that they tried very hard to cancel the appointment or that it was at an inconvenient time. A fifth reported family commitments or being too ill to attend. Over 90% of the patients who missed an appointment subsequently consulted within three months and of these nearly 60% consulted for the stated problem that was going to be presented in the missed consultation. The odds of missing an appointment decreased with increasing age and were greater among those who had missed at least one appointment in the previous 12 months. However, estimates for comparisons between those who missed appointments and the comparison group were imprecise due to the low response rate.
Conclusion
Patients who miss appointments tend to cite practice factors and their own forgetfulness as the main reasons for doing so, and most attend within three months of a missed appointment. This study highlights a number of implications for future research. More work needs to be done to engage people who miss appointments into research in a meaningful way
The JCMT Gould Belt Survey: properties of star-forming filaments in Orion A North
We develop and apply a Hessian-based filament detection algorithm to submillimetre continuum observations of Orion A North. The resultant filament radial density profiles are fitted with beam-convolved line-of-sight Plummer-profiles using Markov chain Monte Carlo techniques. The posterior distribution of the radial decay parameter demonstrates that the majority of filaments exhibit p = 1.5–3, with a mode at p = 2.2, suggesting deviation from the Ostriker p = 4 isothermal, equilibrium, self-gravitating cylinder. The spatial distribution of young stellar objects relative to the high column density filaments is investigated, yielding a lower limit on the star-forming age of the integral-shaped filament ∼1.4 Myr. Additionally, inferred lifetimes of filaments are examined which suggest long-term filament accretion, varying rates of star formation, or both. Theoretical filament stability measures are determined with the aid of HARP C18O J = 3–2 observations and indicate that the majority of filaments are gravitationally subcritical, despite the presence of young protostars. The results from this investigation are consistent with the one-dimensional accretion flow filament model recently observed in numerical simulations
A New Class of Resonances at the Edge of the Two Dimensional Electron Gas
We measure the frequency dependent capacitance of a gate covering the edge
and part of a two-dimensional electron gas in the quantum Hall regime. In
applying a positive gate bias, we create a metallic puddle under the gate
surrounded by an insulating region. Charging of the puddle occurs via electron
tunneling from a metallic edge channel. Analysis of the data allows direct
extraction of this tunneling conductance. Novel conductance resonances appear
as a function of gate bias. Samples with gates ranging from 1-170~m along
the edge display strikingly similar resonance spectra. The data suggest the
existence of unexpected structure, homogeneous over long length scales, at the
sample edge.Comment: 13 pages (revtex) including 4 figure
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