4,602 research outputs found
Recommended from our members
Expression of membrane and nuclear progesterone receptors in two human placental choriocarcinoma cell lines (JEG-3 and BeWo): Effects of syncytialization
This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link -
Copyright @ 2011 Spandidos Publications Ltd.A vital function of the human placenta is to produce steroid hormones such as progesterone, which are essential for the maintenance of pregnancy and the onset of parturition. Although choriocarcinoma cell lines are valuable placental models for investigations of steroid hormone actions, little is known about the expression of progesterone receptors (PRs) in these cell lines. Therefore, in this study, the expression of membrane and nuclear PRs was investigated in cultures of fusigenic (BeWo) and non-fusigenic (JEG-3) human choriocarcinoma cell lines. In addition, the effects of an inducer of syncytialization (forskolin) on the PR expression in BeWo cells were assessed. Quantitative RT-PCR revealed that in fully syncytialized BeWo cells (treated with 50 mu M forskolin for 72 h) there was a significant down-regulation of mPR alpha and up-regulation of mPR beta and of the progesterone membrane component-1 (PGRMC1) when compared with non-syncytialized BeWo cells. Expression of all the mPR and PGRMC1 mRNAs was significantly lower in JEG-3 cells compared to non-syncytialized BeWo cells. Interestingly, expression of PR-B was unaltered between the two BeWo states but was significantly higher in JEG-3 cells. Immunofluorescence analysis revealed that mPR proteins are differentially expressed in these choriocarcinoma cell lines as well as in the human placenta. The data demonstrate that human choriocarcinoma cell lines have a complex system of progesterone signalling involving multiple classes of PRs. The finding that syncytialization is accompanied by changes in the expression of these receptors may suggest that this process influences progesterone signalling
A Study of Giant Pulses from PSR J1824-2452A
We have searched for microsecond bursts of emission from millisecond pulsars
in the globular cluster M28 using the Parkes radio telescope. We detected a
total of 27 giant pulses from the known emitter PSR J1824-2452A. At wavelengths
around 20 cm the giant pulses are scatter-broadened to widths of around 2
microseconds and follow power-law statistics. The pulses occur in two narrow
phase-windows which correlate in phase with X-ray emission and trail the peaks
of the integrated radio pulse-components. Notably, the integrated radio
emission at these phase windows has a steeper spectral index than other
emission. The giant pulses exhibit a high degree of polarization, with many
being 100% elliptically polarized. Their position angles appear random.
Although the integrated emission of PSR J1824-2452A is relatively stable for
the frequencies and bandwidths observed, the intensities of individual giant
pulses vary considerably across our bands. Two pulses were detected at both
2700 and 3500 MHz. The narrower of the two pulses is 20 ns wide at 3500 MHz. At
2700 MHz this pulse has an inferred brightness temperature at maximum of 5 x
10^37 K. Our observations suggest the giant pulses of PSR J1824-2452A are
generated in the same part of the magnetosphere as X-ray emission through a
different emission process to that of ordinary pulses.Comment: Accepted by Ap
Pulsive feedback control for stabilizing unstable periodic orbits in a nonlinear oscillator with a non-symmetric potential
We examine a strange chaotic attractor and its unstable periodic orbits in
case of one degree of freedom nonlinear oscillator with non symmetric
potential. We propose an efficient method of chaos control stabilizing these
orbits by a pulsive feedback technique. Discrete set of pulses enable us to
transfer the system from one periodic state to another.Comment: 11 pages, 4 figure
Cluster approximations for infection dynamics on random networks
In this paper, we consider a simple stochastic epidemic model on large
regular random graphs and the stochastic process that corresponds to this
dynamics in the standard pair approximation. Using the fact that the nodes of a
pair are unlikely to share neighbors, we derive the master equation for this
process and obtain from the system size expansion the power spectrum of the
fluctuations in the quasi-stationary state. We show that whenever the pair
approximation deterministic equations give an accurate description of the
behavior of the system in the thermodynamic limit, the power spectrum of the
fluctuations measured in long simulations is well approximated by the
analytical power spectrum. If this assumption breaks down, then the cluster
approximation must be carried out beyond the level of pairs. We construct an
uncorrelated triplet approximation that captures the behavior of the system in
a region of parameter space where the pair approximation fails to give a good
quantitative or even qualitative agreement. For these parameter values, the
power spectrum of the fluctuations in finite systems can be computed
analytically from the master equation of the corresponding stochastic process.Comment: the notation has been changed; Ref. [26] and a new paragraph in
Section IV have been adde
Breakdown of Conformal Invariance at Strongly Random Critical Points
We consider the breakdown of conformal and scale invariance in random systems
with strongly random critical points. Extending previous results on
one-dimensional systems, we provide an example of a three-dimensional system
which has a strongly random critical point. The average correlation functions
of this system demonstrate a breakdown of conformal invariance, while the
typical correlation functions demonstrate a breakdown of scale invariance. The
breakdown of conformal invariance is due to the vanishing of the correlation
functions at the infinite disorder fixed point, causing the critical
correlation functions to be controlled by a dangerously irrelevant operator
describing the approach to the fixed point. We relate the computation of
average correlation functions to a problem of persistence in the RG flow.Comment: 9 page
“My Future is Now”: A Qualitative Study of Persons Living With Advanced Cancer
Objectives:
Advance care planning (ACP) enables individuals to deliberate about future preferences for care based upon their values and beliefs about what is important in life. For many patients with advanced cancer, however, these critical conversations do not occur. A growing body of literature has examined the end-of-life wishes of seriously ill patients. Few studies have explored what is important to persons as they live with advanced cancer. The aim of the current study was to address this gap and to understand how clinicians can support patients’ efforts to live in the present and plan for the future.
Methods:
Transcriptions of interviews conducted with 36 patients diagnosed with advanced cancer were analyzed using immersion–crystallization, a qualitative research technique.
Results:
Four overarching themes were identified: (I) living in the face of death, (II) who I am, (III) my experience of cancer, and (IV) impact of my illness on others. Twelve subthemes are also reported.
Significance of Results:
These findings have significant implications for clinicians as they partner with patients to plan for the future. Our data suggest that clinicians consider the following 4 prompts: (1) “What is important to you now, knowing that you will die sooner than you want or expected?” (2) “Tell me about yourself.” (3) “Tell me in your own words about your experience with cancer care and treatment.” (4) “What impact has your illness had on others?” In honoring patients’ lived experiences, we may establish the mutual understanding necessary to providing high-quality care that supports patients’ priorities for life
Lightweight Interactions for Reciprocal Cooperation in a Social Network Game
The construction of reciprocal relationships requires cooperative
interactions during the initial meetings. However, cooperative behavior with
strangers is risky because the strangers may be exploiters. In this study, we
show that people increase the likelihood of cooperativeness of strangers by
using lightweight non-risky interactions in risky situations based on the
analysis of a social network game (SNG). They can construct reciprocal
relationships in this manner. The interactions involve low-cost signaling
because they are not generated at any cost to the senders and recipients.
Theoretical studies show that low-cost signals are not guaranteed to be
reliable because the low-cost signals from senders can lie at any time.
However, people used low-cost signals to construct reciprocal relationships in
an SNG, which suggests the existence of mechanisms for generating reliable,
low-cost signals in human evolution.Comment: 13 pages, 2 figure
HALOGAS observations of NGC 5023 and UGC 2082: Modeling of non-cylindrically symmetric gas distributions in edge-on galaxies
In recent years it has become clear that the vertical structure of disk
galaxies is a key ingredient for understanding galaxy evolution. In particular,
the presence and structure of extra-planar gas has been a focus of research.
The Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) survey aims to provide a
census on the rate of cold neutral gas accretion in nearby galaxies as well as
a statistically significant set of galaxies that can be investigated for their
extra-planar gas properties.
In order to better understand the the vertical structure of the neutral
hydrogen in the two edge-on HALOGAS galaxies NGC 5023 and UGC 2082 we construct
detailed tilted ring models. The addition of distortions resembling arcs or
spiral arms significantly improves the fit of the models to these galaxies. In
the case of UGC 2082 no vertical gradient in rotational velocity is required in
either symmetric models nor non-symmetric models to match the observations. The
best fitting model features two arcs of large vertical extent that may be due
to accretion. In the case of NGC 5023 a vertical gradient is required in
symmetric models (dV/dz = km s kpc) and its
magnitude is significantly lowered when non-symmetric models are considered
(dV/dz = km s kpc). Additionally it is shown that the
underlying disk of NGC 5023 can be made symmetric, in all parameters except the
warp, in non-symmetric models. In comparison to the "classical" modeling these
models fit the data significantly better with a limited addition of free
parameters.Comment: 27 Pages, 22 Figures. Accepted for publication in MNRA
Benevolent characteristics promote cooperative behaviour among humans
Cooperation is fundamental to the evolution of human society. We regularly
observe cooperative behaviour in everyday life and in controlled experiments
with anonymous people, even though standard economic models predict that they
should deviate from the collective interest and act so as to maximise their own
individual payoff. However, there is typically heterogeneity across subjects:
some may cooperate, while others may not. Since individual factors promoting
cooperation could be used by institutions to indirectly prime cooperation, this
heterogeneity raises the important question of who these cooperators are. We
have conducted a series of experiments to study whether benevolence, defined as
a unilateral act of paying a cost to increase the welfare of someone else
beyond one's own, is related to cooperation in a subsequent one-shot anonymous
Prisoner's dilemma. Contrary to the predictions of the widely used inequity
aversion models, we find that benevolence does exist and a large majority of
people behave this way. We also find benevolence to be correlated with
cooperative behaviour. Finally, we show a causal link between benevolence and
cooperation: priming people to think positively about benevolent behaviour
makes them significantly more cooperative than priming them to think
malevolently. Thus benevolent people exist and cooperate more
A GBT Survey of the HALOGAS Galaxies and Their Environments I: Revealing the full extent of HI around NGC891, NGC925, NGC4414 & NGC4565
We present initial results from a deep neutral hydrogen (HI) survey of the
HALOGAS galaxy sample, which includes the spiral galaxies NGC891, NGC925,
NGC4414, and NGC4565, performed with the Robert C. Byrd Green Bank Telescope
(GBT). The resulting observations cover at least four deg around these
galaxies with an average 5 detection limit of 1.210
cm over a velocity range of 20 km s and angular scale of 9.1.
In addition to detecting the same total flux as the GBT data, the spatial
distribution of the GBT and original Westerbork Synthesis Radio Telescope
(WSRT) data match well at equal spatial resolutions. The HI mass fraction below
HI column densities of 10 cm is, on average, 2\%. We discuss the
possible origins of low column density HI of nearby spiral galaxies. The
absence of a considerable amount of newly detected HI by the GBT indicates
these galaxies do not have significant extended diffuse HI structures, and
suggests future surveys planned with the SKA and its precursors must go
\textit{at least} as deep as 10 cm in column density to
significantly increase the probability of detecting HI associated with the
cosmic web and/or cold mode accretion.Comment: Accepted for publication in The Astrophysical Journal; 28 pages, 15
figure
- …