2,836 research outputs found
Crossover from spin accumulation into interface states to spin injection in the germanium conduction band
Electrical spin injection into semiconductors paves the way for exploring new
phenomena in the area of spin physics and new generations of spintronic
devices. However the exact role of interface states in spin injection mechanism
from a magnetic tunnel junction into a semiconductor is still under debate. In
this letter, we demonstrate a clear transition from spin accumulation into
interface states to spin injection in the conduction band of -Ge. We observe
spin signal amplification at low temperature due to spin accumulation into
interface states followed by a clear transition towards spin injection in the
conduction band from 200 K up to room temperature. In this regime, the spin
signal is reduced down to a value compatible with spin diffusion model. More
interestingly, we demonstrate in this regime a significant modulation of the
spin signal by spin pumping generated by ferromagnetic resonance and also by
applying a back-gate voltage which are clear manifestations of spin current and
accumulation in the germanium conduction band.Comment: 5 pages, 4 figure
Carbon and Oxygen Galactic Gradients: Observational Values from HII Region Recombination Lines
We present results of deep echelle spectrophotometry of eight Galactic HII
regions located at Galactocentric distances between 6.3 and 10.4 kpc. The data
have been taken with the Very Large Telescope (VLT) Ultraviolet Echelle
Spectrograph (UVES) in the 3100 to 10360 A range. We have derived C++ and O++
abundances from recombination lines for all the objects, as well as O+
abundances from this kind of lines for three of the nebulae. The intensity of
recombination lines is almost independent of the assumed electron temperature
as well as of the possible presence of spatial temperature variations or
fluctuations inside the nebulae. These data allow the determination of the
gas-phase C and O abundance gradients of the Galactic disk, of paramount
importance for chemical evolution models. This is the first time the C gradient
is derived from such a large number of HII regions and for such a wide range of
Galactocentric distances. Abundance gradients are found of the form
log(O/H) = -0.0440.010 dex kpc^-1, log(C/H) =
-0.1030.018 dex kpc^-1, and log(C/O) = -0.0580.018 dex
kpc^-1.Comment: 13 pages, 2 tables, 2 figures. Published in ApJ Letters, 618, L9
EP05.02-003 Durvalumab after Chemoradiotherapy (CRT) in Unresectable Stage III NSCLC. Comparative Study of Two Cohorts in the Real-World Setting
[EN] Introduction: Durvalumab is the new standard of care for unresectable
locally advanced NSCLC, with PD-L1 _1% and who did not
have progression after CRT treatment in the European Union. Our
study compares the effectiveness and the frequency of radiation
pneumonitis in patients treated with concurrent CRT with or without
durvalumab consolidation during the same period in real clinical
practice. Methods: A single-center retrospective study. 71 treated
patients with unresectable stage III NSCLC were included between
March 2018 and December 2021, 37 with CRT followed by durvalumab
and 34 with CRT alone. Real-world progression-free survival
(rwPFS) and real-world overall survival (rwOS) were calculated since
the date of the end CRT. Propensity score matching (PSM) 1:1 was
used to account for differences in baseline characteristics. Results:
Median age was 67 years (range 46-82). 25.4% of the patients were
_75 years old. 78.9% were men and 53.5% former smokers. 54.9%
had squamous histology and 28%, 51% and 21% stage IIIA, IIIB and
IIIC disease, respectively. The most used scheme was carboplatinpaclitaxel
(43.7%), receiving induction chemotherapy in up to 54.9%
of patients. 73.2% received between 60-66 Gy doses of radiotherapy.
Median time from end of CRT to onset durvalumab was 44 days
(range 13-120) with a median of 14 infusions (range 6-27). Of the
34 patients without durvalumab treatment, the expression PD-L1
<1% (58.8%) was the most frequent cause for rejecting consolidation
therapy. After PSM analysis, patients distributions were well
balanced. With a median follow-up of 19.7 months (range 1.4-36.6);
median rw-PFS was 9.3 months (95% CI, 5-13.5) without durvalumab
and 17 months (95% CI, 11-22.9) with durvalumab (p¼0.013).
Median rw-OS was 19.3 months (95% CI, 3.8-34.8) without durvalumab
and 29.9 months (95% CI, 23.3-36.6) with durvalumab
(p¼0.241) with a rw-OS% at 6, 18 and 24 months of 90%, 62% and
49% vs 100%, 86% and 74%, respectively. The rate of radiation
pneumonitis was more frequent with durvalumab consolidation
(56.8% against 44.1%), (p¼0.346), especially within 3 months after
CRT. G3 pneumonitis was only observed in the consolidation therapy.
Conclusions: Our results demonstrate the effectiveness of
durvalumab consolidation after CRT in real-world patients with
unresectable stage III NSCLC. Further sample and longer follow-up
are required to obtain more accurate results. Active surveillance and
appropriate management for radiation pneumonitis are needed, in
especially in candidates for consolidation treatmentS
EP05.02-002 Who Benefits More of Durvalumab after Chemoradiotherapy (CRT) in Real-World Patients with Locally Advanced Non-Small-Cell Lung Cancer (NSCLC)?
[EN] Introduction: Durvalumab received EMA approval as consolidation
therapy (CT) for unresectable stage III NSCLC with PD-L1 _1% and
who did not have progression after CRT. Our objective was to analyze
in real clinical practice the effectiveness of durvalumab and explore the
clinical factors that may be associated with the benefit from CT.
Methods: Retrospective study was made at Hospital of Leon (Spain),
including 37 patients with locally advanced NSCLC treated with durvalumab
after CRT treatment between March 2018 and october 2021
(40.5% patients were included in the durvalumab early access program).
The neutrophil-to-lymphocyte ratio (NLR) could identified after
CRT as a factor that may be benefit from durvalumab. Results: Median
age was 67 years (range 46-82 years). 40.5% of patients were _70
years old. 78.4% were male and 51.4% smokers. 54% had non-squamous
histology. PD-L1 expression was <1% in 5% and not available in
8% patients. 2.7% ROS1 rearrangements, 5.4% KRAS mutations and
not available in 43.2% patients. Stage IIIA, IIIB, IIIC disease were
24.3%, 54.1% and 21.6%, respectively. Median time from end of CRT to
onset durvalumab was 44 days (range 13-120 days). Overall median CT
duration was 214.8 days (range 69-399 days) with a median of 14
infusions (range 6-27 infusions). With a median follow up of 19.7
months (range 1.4-34.9 months); 67.6% had stopped CT: 37.8% due to
completing treatment, 16.2% disease progression, 10.8% adverse event
and 2.7% due to COVID19 infection. Median real-world progressionfree
survival (rwPFS) was 17 months (95% CI, 11-23). Median realworld
overall survival (rwOS) was 29.9 months (95% CI, 23.3-36.6). %
rwOS at 6, 18 and 24 months were 100%, 86.9% and 74.5%, respectively.
For patients with post-CRT NLR not exceeding the cohort median
value of 6, receipt of durvalumab was associated with an improvement
in rwOS (median not reached vs 25.7 months; p¼0.025). 56.8% patients
had any grade of radiation pneumonitis (median time from CRT
start: 119 days [range 36-241 days]). Of these, 19% patients developed
worsening of radiation pneumonitis with durvalumab. 54,1% developed
immune-mediated toxicity, mostly G1-2 (85.1%). Conclusions:
Our results demonstrate the effectiveness of durvalumab consolidation
in this patients population in a real-life setting. We identified low NLR
after CRT as a potentially predictive factor for the benefit of CT in
locally advanced NSCLC.S
COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408-5354 with high-cadence photometric monitoring
We present time-delay measurements for the new quadruply imaged quasar DES
J0408-5354, the first quadruply imaged quasar found in the Dark Energy Survey
(DES). Our result is made possible by implementing a new observational strategy
using almost daily observations with the MPIA 2.2m telescope at La Silla
observatory and deep exposures reaching a signal-to-noise ratio of about 1000
per quasar image. This data quality allows us to catch small photometric
variations (a few mmag rms) of the quasar, acting on temporal scales much
shorter than microlensing, hence making the time delay measurement very robust
against microlensing. In only 7 months we measure very accurately one of the
time delays in DES J0408-5354: Dt(AB) = -112.1 +- 2.1 days (1.8%) using only
the MPIA 2.2m data. In combination with data taken with the 1.2m Euler Swiss
telescope, we also measure two delays involving the D component of the system
Dt(AD) = -155.5 +- 12.8 days (8.2%) and Dt(BD) = -42.4 +- 17.6 days (41%),
where all the error bars include systematics. Turning these time delays into
cosmological constraints will require deep HST imaging or ground-based Adaptive
Optics (AO), and information on the velocity field of the lensing galaxy.Comment: 9 pages, 5 figures, accepted for publication in Astronomy &
Astrophysic
Long-Term Evolution of the Aerosol Debris Cloud Produced by the 2009 Impact on Jupiter
We present a study of the long-term evolution of the cloud of aerosols produced in the atmosphere of Jupiter by the impact of an object on 19 July 2009. The work is based on images obtained during 5 months from the impact to 31 December 2009 taken in visible continuum wavelengths and from 20 July 2009 to 28 May 2010 taken in near-infrared deep hydrogen-methane absorption bands at 2.1-2.3 micron. The impact cloud expanded zonally from approximately 5000 km (July 19) to 225,000 km (29 October, about 180 deg in longitude), remaining meridionally localized within a latitude band from 53.5 deg S to 61.5 deg S planetographic latitude. During the first two months after its formation the site showed heterogeneous structure with 500-1000 km sized embedded spots. Later the reflectivity of the debris field became more homogeneous due to clump mergers. The cloud was mainly dispersed in longitude by the dominant zonal winds and their meridional shear, during the initial stages, localized motions may have been induced by thermal perturbation caused by the impact's energy deposition. The tracking of individual spots within the impact cloud shows that the westward jet at 56.5 deg S latitude increases its eastward velocity with altitude above the tropopause by 5- 10 m/s. The corresponding vertical wind shear is low, about 1 m/s per scale height in agreement with previous thermal wind estimations. We found evidence for discrete localized meridional motions with speeds of 1-2 m/s. Two numerical models are used to simulate the observed cloud dispersion. One is a pure advection of the aerosols by the winds and their shears. The other uses the EPIC code, a nonlinear calculation of the evolution of the potential vorticity field generated by a heat pulse that simulates the impact. Both models reproduce the observed global structure of the cloud and the dominant zonal dispersion of the aerosols, but not the details of the cloud morphology. The reflectivity of the impact cloud decreased exponentially with a characteristic timescale of 15 days; we can explain this behavior with a radiative transfer model of the cloud optical depth coupled to an advection model of the cloud dispersion by the wind shears. The expected sedimentation time in the stratosphere (altitude levels 5-100 mbar) for the small aerosol particles forming the cloud is 45-200 days, thus aerosols were removed vertically over the long term following their zonal dispersion. No evidence of the cloud was detected 10 months after the impact
Ultrafast spin-currents and charge conversion at \u3ci\u3e3d-5d\u3c/i\u3e interfaces probed by time-domain terahertz spectroscopy
Spintronic structures are extensively investigated for their spin-orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering for the optimization of spin transmission. Here, we advance the analysis of ultrafast spin-charge conversion phenomena at ferromagnetic-Transition metal interfaces due to their inverse spin-Hall effect properties. In particular, the intrinsic inverse spin-Hall effect of Pt-based systems and extrinsic inverse spin-Hall effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The spin-charge conversion is probed by complementary techniques-ultrafast THz time-domain spectroscopy in the dynamic regime for THz pulse emission and ferromagnetic resonance spin-pumping measurements in the GHz regime in the steady state-to determine the role played by the material properties, resistivities, spin transmission at metallic interfaces, and spin-flip rates. These measurements show the correspondence between the THz time-domain spectroscopy and ferromagnetic spin-pumping for the different set of samples in term of the spin mixing conductance. The latter quantity is a critical parameter, determining the strength of the THz emission from spintronic interfaces. This is further supported by ab initio calculations, simulations, and analysis of the spin-diffusion and spin-relaxation of carriers within the multilayers in the time domain, permitting one to determine the main trends and the role of spin transmission at interfaces. This work illustrates that time-domain spectroscopy for spin-based THz emission is a powerful technique to probe spin-dynamics at active spintronic interfaces and to extract key material properties for spin-charge conversion
- …