1,812 research outputs found
Scalp cooling with adjuvant/neoadjuvant chemotherapy for breast cancer and the risk of scalp metastases: systematic review and meta-analysis.
PurposeThe risk of scalp metastases in patients using scalp cooling for preservation of hair during chemotherapy has been a concern but is poorly described.MethodsA systematic review and meta-analysis of longitudinal studies was undertaken to evaluate the effect of scalp cooling versus no scalp cooling on the risk of scalp metastasis in patients treated for breast cancer with chemotherapy. Electronic databases, journal specific, and hand searches of articles identified were searched. Patients were matched based on disease, treatment, lack of metastatic disease, and sex.ResultsA total of 24 full-text articles were identified for review. Of these articles, ten quantified the incidence of scalp metastasis with scalp cooling over time. For scalp cooling, 1959 patients were evaluated over an estimated mean time frame of 43.1Â months. For no scalp cooling, 1238 patients were evaluated over an estimated mean time frame of 87.4Â months. The incidence rate of scalp metastasis in the scalp cooling group versus the no scalp cooling group was 0.61% (95% CI 0.32-1.1%) versus 0.41% (95% CI 0.13-0.94%); PÂ =Â 0.43.ConclusionThe incidence of scalp metastases was low regardless of scalp cooling. This analysis suggests that scalp cooling does not increase the incidence of scalp metastases
Ambipolar charge injection and transport in a single pentacene monolayer island
Electrons and holes are locally injected in a single pentacene monolayer
island. The two-dimensional distribution and concentration of the injected
carriers are measured by electrical force microscopy. In crystalline monolayer
islands, both carriers are delocalized over the whole island. On disordered
monolayer, carriers stay localized at their injection point. These results
provide insight into the electronic properties, at the nanometer scale, of
organic monolayers governing performances of organic transistors and molecular
devices.Comment: To be published in Nano Letter
Physical Study by Surface Characterizations of Sarin Sensor on the Basis of Chemically Functionalized Silicon Nanoribbon Field Effect Transistor
Surface characterizations of an organophosphorus (OP) gas detector based on
chemically functionalized silicon nanoribbon field-effect transistor (SiNR-FET)
were performed by Kelvin Probe Force Microscopy (KPFM) and ToF-SIMS, and
correlated with changes in the current-voltage characteristics of the devices.
KPFM measurements on FETs allow (i) to investigate the contact potential
difference (CPD) distribution of the polarized device as function of the gate
voltage and the exposure to OP traces and, (ii) to analyze the CPD hysteresis
associated to the presence of mobile ions on the surface. The CPD measured by
KPFM on the silicon nanoribbon was corrected due to side capacitance effects in
order to determine the real quantitative surface potential. Comparison with
macroscopic Kelvin probe (KP) experiments on larger surfaces was carried out.
These two approaches were quantitatively consistent. An important increase of
the CPD values (between + 399 mV and + 302 mV) was observed after the OP sensor
grafting, corresponding to a decrease of the work function, and a weaker
variation after exposure to OP (between - 14 mV and - 61 mV) was measured.
Molecular imaging by ToF-SIMS revealed OP presence after SiNR-FET exposure. The
OP molecules were essentially localized on the Si-NR confirming effectiveness
and selectivity of the OP sensor. A prototype was exposed to Sarin vapors and
succeeded in the detection of low vapor concentrations (40 ppm).Comment: Paper and supporting information, J. Phys. Chem. C, 201
Bond-randomness-induced Neel order in weakly coupled antiferromagnetic spin chains
Quasi-one-dimensional antiferromagnetic (AF) quantum spin systems show a wide
range of interesting phenomena such as the spin-Peierls transition and disorder
driven long range ordering. While there is no magnetic long range order in
strictly one-dimensional systems, in real systems some amount of interchain
coupling is always present and AF long range order may appear below a Neel
ordering temperature T_N. We study the effect of bond randomness on Neel
ordering in weakly coupled random AF S=1/2 chains both with and without
dimerization (or spin-Peierls order). We use the real space renormalization
group method to tackle the intrachain couplings, and a mean-field approximation
to treat the interchain coupling. We show that in the non-dimerized chain,
disorder (represented by bond randomness) enhances the Neel order parameter; in
the dimerized chain which shows no magnetic ordering in the weak interchain
coupling limit without randomness, disorder can actually lead to long range
order. Thus disorder is shown to lead to, or enhance the tendency toward long
range order, providing another example of the order-by-disorder phenomenon. We
make a qualitative comparison of our results with the observed phenomenon of
doping induced long range ordering in quasi-one-dimensional spin systems such
as CuGeO_3.Comment: 8 pages, 4 figure
Cassini observations of ion and electron beams at Saturn and their relationship to infrared auroral arcs
We present Cassini Visual and Infrared Mapping Spectrometer observations of infrared auroral emissions from the noon sector of Saturn's ionosphere revealing multiple intense auroral arcs separated by dark regions poleward of the main oval. The arcs are interpreted as the ionospheric signatures of bursts of reconnection occurring at the dayside magnetopause. The auroral arcs were associated with upward field-aligned currents, the magnetic signatures of which were detected by Cassini at high planetary latitudes. Magnetic field and particle observations in the adjacent downward current regions showed upward bursts of 100â360 keV light ions in addition to energetic (hundreds of keV) electrons, which may have been scattered from upward accelerated beams carrying the downward currents. Broadband, upward propagating whistler waves were detected simultaneously with the ion beams. The acceleration of the light ions from low altitudes is attributed to wave-particle interactions in the downward current regions. Energetic (600 keV) oxygen ions were also detected, suggesting the presence of ambient oxygen at altitudes within the acceleration region. These simultaneous in situ and remote observations reveal the highly energetic magnetospheric dynamics driving some of Saturn's unusual auroral features. This is the first in situ identification of transient reconnection events at regions magnetically conjugate to Saturn's magnetopause
Prospects for high-z cluster detections with Planck, based on a follow-up of 28 candidates using MegaCam@CFHT
The Planck catalogue of SZ sources limits itself to a significance threshold
of 4.5 to ensure a low contamination rate by false cluster candidates. This
means that only the most massive clusters at redshift z>0.5, and in particular
z>0.7, are expected to enter into the catalogue, with a large number of systems
in that redshift regime being expected around and just below that threshold. In
this paper, we follow-up a sample of SZ sources from the Planck SZ catalogues
from 2013 and 2015. In the latter maps, we consider detections around and at
lower significance than the threshold adopted by the Planck Collaboration. To
keep the contamination rate low, our 28 candidates are chosen to have
significant WISE detections, in combination with non-detections in SDSS/DSS,
which effectively selects galaxy cluster candidates at redshifts .
By taking r- and z-band imaging with MegaCam@CFHT, we bridge the 4000A
rest-frame break over a significant redshift range, thus allowing accurate
redshift estimates of red-sequence cluster galaxies up to z~0.8. After
discussing the possibility that an overdensity of galaxies coincides -by
chance- with a Planck SZ detection, we confirm that 16 of the candidates have
likely optical counterparts to their SZ signals, 13 (6) of which have an
estimated redshift z>0.5 (z>0.7). The richnesses of these systems are generally
lower than expected given the halo masses estimated from the Planck maps.
However, when we follow a simplistic model to correct for Eddington bias in the
SZ halo mass proxy, the richnesses are consistent with a reference
mass-richness relation established for clusters detected at higher
significance. This illustrates the benefit of an optical follow-up, not only to
obtain redshift estimates, but also to provide an independent mass proxy that
is not based on the same data the clusters are detected with, and thus not
subject to Eddington bias.Comment: 13 pages, 7 figures. Accepted for publication in A&
Collapse and recovery of forage fish populations prior to commercial exploitation
We use a new, wellâcalibrated 500 year paleorecord off southern California to determine collapse frequency, cross correlation, persistence, and return times of exploited forage fish populations. The paleorecord shows that âcollapseâ (defined as <10% of the mean peak biomass) is a normal state repeatedly experienced by northern anchovy, Pacific hake, and Pacific sardine which were collapsed 29â40% of the time, prior to commercial fishing exploitation. Mean (± SD) persistence of âfishable biomassâ (defined as one third mean peak biomass from the paleorecord) was 19 ± 18, 15 ± 17, and 12 ± 7 years for anchovy, hake, and sardine. Mean return times to the same biomass was 8 years for anchovy but 22 years for sardine and hake. Further, we find that sardine and anchovy are positively correlated over 400 years, consistent with coherent declines of both species off California. Persistence and return times combined with positive sardineâanchovy correlation indicate that on average 1â2 decades of fishable biomass will be followed by 1â2 decades of low forage. Forage populations are resilient on the 500 year time scale, but their collapse and recovery cycle (based on the paleorecord) are suited to alternating periods of high fishing mortality and periods of little or no fishing.Key PointsThe paleorecord shows that âcollapseâ is a normal state repeatedly experienced by northern anchovy, Pacific hake, and Pacific sardineMean return times to âfishableâ biomass was 8 years for anchovy, but 22 years for sardine and hake, and persistence was of the same orderSardine and anchovy are positively correlated over 400 years, consistent with coherent declines of both species off CaliforniaPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136405/1/grl55551.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136405/2/grl55551_am.pd
Power-Laws in Nonlinear Granular Chain under Gravity
The signal generated by a weak impulse propagates in an oscillatory way and
dispersively in a gravitationally compacted granular chain. For the power-law
type contact force, we show analytically that the type of dispersion follows
power-laws in depth. The power-law for grain displacement signal is given by
where and denote depth and the exponent of contact
force, and the power-law for the grain velocity is . Other
depth-dependent power-laws for oscillation frequency, wavelength, and period
are given by combining above two and the phase velocity power-law
. We verify above power-laws by comparing with the data
obtained by numerical simulations.Comment: 12 pages, 3 figures; Changed conten
Production of intense highly charged ion beams with SERSE
The source SERSE is operational at LNS since June 1998 and many improvements have been carried out in this period. The frequency has been increased from 14.5 GHz to 18 GHz and the use of two frequency heating has given positive results. Metallic ion production has been tested by means of a high temperature oven and the preliminary results are described. Tests of magnetic field scaling and frequency scaling have confirmed the results of previous tests with SC-ECRIS at lower frequency and seems to suggest that the upgrading of the source to higher frequency may be considered
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