1,214 research outputs found
Prospects in Constraining the Dark Energy Potential
We generalize to non-flat geometries the formalism of Simon et al. (2005) to
reconstruct the dark energy potential. This formalism makes use of quantities
similar to the Horizon-flow parameters in inflation, can, in principle, be made
non-parametric and is general enough to be applied outside the simple, single
scalar field quintessence. Since presently available and forthcoming data do
not allow a non-parametric and exact reconstruction of the potential, we
consider a general parametric description in term of Chebyshev polynomials. We
then consider present and future measurements of H(z), Baryon Acoustic
Oscillations surveys and Supernovae type 1A surveys, and investigate their
constraints on the dark energy potential. We find that, relaxing the flatness
assumption increases the errors on the reconstructed dark energy evolution but
does not open up significant degeneracies, provided that a modest prior on
geometry is imposed. Direct measurements of H(z), such as those provided by BAO
surveys, are crucially important to constrain the evolution of the dark energy
potential and the dark energy equation of state, especially for non-trivial
deviations from the standard LambdaCDM model.Comment: 22 pages, 7 figures. 2 references correcte
Anti-angiogenic and anti-proliferative graphene oxide nanosheets for tumor cell therapy
Graphene oxide (GO) is a bidimensional novel material that exhibits high biocompatibility and angiogenic properties, mostly related to the intracellular formation of reactive oxygen species (ROS). In this work, we set up an experimental methodology for the fabrication of GO@peptide hybrids by the immobilization, via irreversible physical adsorption, of the Ac-(GHHPH)4-NH2 peptide sequence, known to mimic the anti-angiogenic domain of the histidine-proline-rich glycoprotein (HPRG). The anti-proliferative capability of the graphene-peptide hybrids were tested in vitro by viability assays on prostate cancer cells (PC-3 line), human neuroblastoma (SH-SY5Y), and human retinal endothelial cells (primary HREC). The anti-angiogenic response of the two cellular models of angiogenesis, namely endothelial and prostate cancer cells, was scrutinized by prostaglandin E2 (PGE2) release and wound scratch assays, to correlate the activation of inflammatory response upon the cell treatments with the GO@peptide nanocomposites to the cell migration processes. Results showed that the GO@peptide nanoassemblies not only effectively induced toxicity in the prostate cancer cells, but also strongly blocked the cell migration and inhibited the prostaglandin-mediated inflammatory process both in PC-3 and in HRECs. Moreover, the cytotoxic mechanism and the internalization efficiency of the theranostic nanoplatforms, investigated by mitochondrial ROS production analyses and confocal microscopy imaging, unraveled a dose-dependent manifold mechanism of action performed by the hybrid nanoassemblies against the PC-3 cells, with the detection of the GO-characteristic cell wrapping and mitochondrial perturbation. The obtained results pointed out to the very promising potential of the synthetized graphene-based hybrids for cancer therapy
Observational signatures of Jordan-Brans-Dicke theories of gravity
We analyze the Jordan-Brans-Dicke model (JBD) of gravity, where deviations
from General Relativity (GR) are described by a scalar field non-minimally
coupled to gravity. The theory is characterized by a constant coupling
parameter, ; GR is recovered in the limit . In such theories, gravity modifications manifest at early times,
so that one cannot rely on the usual approach of looking for inconsistencies in
the expansion history and perturbations growth in order to discriminate between
JBD and GR. However, we show that a similar technique can be successfully
applied to early and late times observables instead. Cosmological parameters
inferred extrapolating early-time observations to the present will match those
recovered from direct late-time observations only if the correct gravity theory
is used. We use the primary CMB, as will be seen by the Planck satellite, as
the early-time observable; and forthcoming and planned Supernov{\ae}, Baryonic
Acoustic Oscillations and Weak Lensing experiments as late-time observables. We
find that detection of values of as large as 500 and 1000 is
within reach of the upcoming (2010) and next-generation (2020) experiments,
respectively.Comment: minor revision, references added, matching version published in JCA
First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Inflation
We confront predictions of inflationary scenarios with the WMAP data, in
combination with complementary small-scale CMB measurements and large-scale
structure data. The WMAP detection of a large-angle anti-correlation in the
temperature--polarization cross-power spectrum is the signature of adiabatic
superhorizon fluctuations at the time of decoupling. The WMAP data are
described by pure adiabatic fluctuations: we place an upper limit on a
correlated CDM isocurvature component. Using WMAP constraints on the shape of
the scalar power spectrum and the amplitude of gravity waves, we explore the
parameter space of inflationary models that is consistent with the data. We
place limits on inflationary models; for example, a minimally-coupled lambda
phi^4 is disfavored at more than 3-sigma using WMAP data in combination with
smaller scale CMB and large scale structure survey data. The limits on the
primordial parameters using WMAP data alone are: n_s(k_0=0.002
Mpc^{-1})=1.20_{-0.11}^{+0.12}, dn/dlnk=-0.077^{+0.050}_{- 0.052}, A(k_0=0.002
Mpc}^{-1})=0.71^{+0.10}_{-0.11} (68% CL), and r(k_0=0.002 Mpc^{-1})<1.28 (95%
CL).Comment: Accepted by ApJ; 49 pages, 9 figures. V2: Gives constraints from WMAP
data alone. Corrected approximation which made the constraints in Table 1 to
shift slightly. Corrected the Inflation Flow following the revision to
Kinney, astro-ph/0206032. No conclusions have been changed. For a detailed
list of changes see http://www.astro.princeton.edu/~hiranya/README.ERRATA.tx
Neoadjuvant eribulin mesylate following anthracycline and taxane in triple negative breast cancer: Results from the HOPE study
Background Eribulin mesylate (E) is indicated for metastatic breast cancer patients previously treated with anthracycline and taxane. We argued that E could also benefit patients eligible for neoadjuvant chemotherapy. Methods Patients with primary triple negative breast cancer 2 cm received doxorubicin 60 mg/m2 and paclitaxel 200 mg/m2 x 4 cycles (AT) followed by E 1.4 mg/m2 x 4 cycles. Primary endpoint was pathological complete response (pCR) rate; secondary and explorative endpoints included clinical/metabolic response rates and safety, and biomarker analysis, respectively. Using a two-stage Simon design, 43 patients were to be included provided that 4 of 13 patients had achieved pCR in the first stage of the study. Results In stage I of the study 13 women were enrolled, median age 43 years, tumor size 2–5 cm in 9/13 (69%), positive nodal status in 8/13 (61%). Main grade 3 adverse event was neutropenia (related to AT and E in 4 and 2 cases, respectively). AT followed by E induced clinical complete + partial responses in 11/13 patients (85%), pCR in 3/13 (23%). Median measurements of maximum standardized uptake value (SUVmax) resulted 13, 3, and 1.9 at baseline, after AT and E, respectively. Complete metabolic response (CMR) occurred after AT and after E in 2 and 3 cases, respectively. Notably, 2 of the 5 (40%) patients with CMR achieved pCR at surgery. Immunostaining of paired pre-/post-treatment tumor specimens showed a reduction of β-catenin, CyclinD1, Zeb-1, and c-myc expression, in the absence of N-cadherin modulation. The study was interrupted at stage I due to the lack of the required patients with pCR. Conclusions Despite the early study closure, preoperative E following AT showed clinical and biological activity in triple negative breast cancer patients. Furthermore, the modulation of β-catenin pathway core proteins, supposedly outside the domain of epithelial–mesenchymal transition, claims for further investigation. Trial registration EU Clinical Trial Register, EudraCT number 2012-004956-12
First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectrum
We present the angular power spectrum derived from the first-year Wilkinson
Microwave Anisotropy Probe (WMAP) sky maps. We study a variety of power
spectrum estimation methods and data combinations and demonstrate that the
results are robust. The data are modestly contaminated by diffuse Galactic
foreground emission, but we show that a simple Galactic template model is
sufficient to remove the signal. Point sources produce a modest contamination
in the low frequency data. After masking ~700 known bright sources from the
maps, we estimate residual sources contribute ~3500 uK^2 at 41 GHz, and ~130
uK^2 at 94 GHz, to the power spectrum l*(l+1)*C_l/(2*pi) at l=1000. Systematic
errors are negligible compared to the (modest) level of foreground emission.
Our best estimate of the power spectrum is derived from 28 cross-power spectra
of statistically independent channels. The final spectrum is essentially
independent of the noise properties of an individual radiometer. The resulting
spectrum provides a definitive measurement of the CMB power spectrum, with
uncertainties limited by cosmic variance, up to l~350. The spectrum clearly
exhibits a first acoustic peak at l=220 and a second acoustic peak at l~540 and
it provides strong support for adiabatic initial conditions. Kogut et al.
(2003) analyze the C_l^TE power spectrum, and present evidence for a relatively
high optical depth, and an early period of cosmic reionization. Among other
things, this implies that the temperature power spectrum has been suppressed by
\~30% on degree angular scales, due to secondary scattering.Comment: One of thirteen companion papers on first-year WMAP results submitted
to ApJ; 44 pages, 14 figures; a version with higher quality figures is also
available at http://lambda.gsfc.nasa.gov/product/map/map_bibliography.htm
N-body simulations with generic non-Gaussian initial conditions I: Power Spectrum and halo mass function
We address the issue of setting up generic non-Gaussian initial conditions
for N-body simulations. We consider inflationary-motivated primordial
non-Gaussianity where the perturbations in the Bardeen potential are given by a
dominant Gaussian part plus a non-Gaussian part specified by its bispectrum.
The approach we explore here is suitable for any bispectrum, i.e. it does not
have to be of the so-called separable or factorizable form. The procedure of
generating a non-Gaussian field with a given bispectrum (and a given power
spectrum for the Gaussian component) is not univocal, and care must be taken so
that higher-order corrections do not leave a too large signature on the power
spectrum. This is so far a limiting factor of our approach. We then run N-body
simulations for the most popular inflationary-motivated non-Gaussian shapes.
The halo mass function and the non-linear power spectrum agree with theoretical
analytical approximations proposed in the literature, even if they were so far
developed and tested only for a particular shape (the local one). We plan to
make the simulations outputs available to the community via the non-Gaussian
simulations comparison project web site
http://icc.ub.edu/~liciaverde/NGSCP.html.Comment: 23 pages, 10 figure
Cosmological Parameters Degeneracies and Non-Gaussian Halo Bias
We study the impact of the cosmological parameters uncertainties on the
measurements of primordial non-Gaussianity through the large-scale non-Gaussian
halo bias effect. While this is not expected to be an issue for the standard
LCDM model, it may not be the case for more general models that modify the
large-scale shape of the power spectrum. We consider the so-called local
non-Gaussianity model and forecasts from planned surveys, alone and combined
with a Planck CMB prior. In particular, we consider EUCLID- and LSST-like
surveys and forecast the correlations among and the running of the
spectral index , the dark energy equation of state , the effective
sound speed of dark energy perturbations , the total mass of massive
neutrinos , and the number of extra relativistic degrees of
freedom . Neglecting CMB information on and scales /Mpc, we find that, if is assumed to be known, the
uncertainty on cosmological parameters increases the error on by
10 to 30% depending on the survey. Thus the constraint is
remarkable robust to cosmological model uncertainties. On the other hand, if
is simultaneously constrained from the data, the
error increases by . Finally, future surveys which provide a large
sample of galaxies or galaxy clusters over a volume comparable to the Hubble
volume can measure primordial non-Gaussianity of the local form with a
marginalized 1-- error of the order , after
combination with CMB priors for the remaining cosmological parameters. These
results are competitive with CMB bispectrum constraints achievable with an
ideal CMB experiment.Comment: 17 pages, 1 figure added, typos corrected, comments added, matches
the published versio
Is Adnexectomy Mandatory at the Time of Hysterectomy for Uterine Sarcomas? A Systematic Review and Meta-Analysis.
Background and Objectives: Uterine sarcomas represents only 3% of all the female genital tract ones. The tumoral stage is the most significant prognostic factor. The role of the bilateral salpingo-oophorectomy (BSO) in the surgical management of FIGO stage IA and IB appears still controversial. This review aims to investigate the impact of bilateral adnexectomy in the treatment of uterine sarcoma. Methods: Following the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically searched the PubMed, Scopus, Cochrane, Medline, and Medscape databases in February 2022. We applied no language or geographical restrictions, but we considered only English studies. We included the studies containing data about Recurrence Rate (RR), Disease-free Survival (DFS), and Overall Survival (OS). We used comparative studies for meta-analysis. Results: Seventeen studies fulfilled the inclusion criteria; 2 retrospective observational studies, and 15 retrospective comparative studies, And 14 out of the 15 comparative studies were enrolled in meta-analysis. A total of 3743 patients were analyzed concerning the use of adnexectomy with hysterectomy in patients with uterine sarcoma and compared with those who did not. Meta-analysis highlighted a non-significant worsening of the OS in the BSO group compared to the OP group and showed that adnexectomy does not improve the DFS (BSO OR 1.23 (95% CI 0.81–1.85) p = 0.34; I(2) = 24% p = 0.22). Conclusions: Most studies selected for our review showed that adnexectomy does not significantly affect the RR, OS, and PFS in treating FIGO stage I uterine sarcomas. Therefore, even if there is a unanimous consensus about bilateral adnexectomy in menopausal patients, preservation of ovarian tissue may be considered in premenopausal women. Nonetheless, there are not enough cases in the literature to recommend this procedure
- …