7,392 research outputs found
Necrotizing vasculitis and exacerbation of psoriasis after granulocyte colony-stimulating factor for small cell lung carcinoma
Critical light instability in CB/DIO processed PBDTTT-EFT:PC<inf>71</inf>BM organic photovoltaic devices
Organic photovoltaic (OPV) devices often undergo ‘burn-in’ during the early stages of operation, this period describing the relatively rapid drop in power output before stabilising. For normal and inverted PBDTTT-EFT:PC71BM OPVs prepared according to current protocols, we identify a critical and severe light-induced burn-in phase that reduces power conversion efficiency by at least 60% after 24 hours simulated AM1.5 illumination. Such losses result primarily from a reduction in photocurrent, and for inverted devices we correlate this process in-situ with the simultaneous emergence of space-chare effects on the μs timescale. The effects of burn in are also found to reduce the lifetime of photogenerated charge carriers, as determine by in-situ transient photovoltage measurements. To identify the underlying mechanisms of this instability, a range of techniques are employed ex-situ to separate bulk- and electrode-specific degradation processes. We find that whilst the active layer nanostructure and kinetics of free charge generation remain unchanged, partial photobleaching (6% of film O.D.) of PBDTTT-EFT:PC71BM occurs alongside an increase in the ground state bleach decay time of PBDTTT-EFT. We hypothesise that this latter observation may reflect relaxation from excited states on PBDTTT-EFT that do not undergo dissociation into free charges. Owing to the poor lifetime of the reference PBDTTT-EFT:PC71BM OPVs, the fabrication protocol is modified to identify routes for stability enhancement in this initially promising solar cell blend.The authors would like to thank SABIC for partially funding this research. PEH, EC, RHF and NCG thank the EPSRC for funding through the Supergen Supersolar Consortium (EP/J017361/1). PEH also thanks CKIK for additional funding. KD thanks the Gates Cambridge Scholarship fund. MAJ thanks Nyak Technology Ltd for PhD scholarship funding. AJP thanks David Lidzey (University of Sheffield) for use of a sample chamber for X-ray scattering measurements and Adam Brown (University of Cambridge) for UPS measurements.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.orgel.2015.12.02
Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape
We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064 nm pulsed beams propagate from wider (122 µm) into smaller (37 µm) diameter. In the passive mode, increasing the input beam peak power above 20 kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600 nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length
SN 2007od: A Type IIP SN with Circumstellar Interaction
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP
supernova (SN). Optical V band photometry reveals a very steep brightness
decline between the plateau and nebular phases of ~4.5 mag, likely due to SN
2007od containing a low mass of 56Ni. The optical spectra show an evolution
from normal Type IIP with broad Halpha emission, to a complex, four component
Halpha emission profile exhibiting asymmetries caused by dust extinction after
day 232. This is similar to the spectral evolution of the Type IIn SN 1998S,
although no early-time narrow (~200 km s-1) Halpha component was present in SN
2007od. In both SNe, the intermediate-width Halpha emission components are
thought to arise in the interaction between the ejecta and its circumstellar
medium (CSM). SN 2007od also shows a mid-IR excess due to new dust. The
evolution of the Halpha profile and the presence of the mid-IR excess provide
strong evidence that SN 2007od formed new dust before day 232. Late-time
observations reveal a flattening of the visible lightcurve. This flattening is
a strong indication of the presence of a light echo, which likely accounts for
much of the broad, underlying Halpha component seen at late-times. We believe
the multi-peaked Halpha emission is consistent with the interaction of the
ejecta with a circumstellar ring or torus (for the inner components at \pm1500
km s-1), and a single blob or cloud of circumstellar material out of the plane
of the CSM ring (for the outer component at -5000 km s-1). The most probable
location for the formation of new dust is in the cool dense shell created by
the interaction between the expanding ejecta and its CSM. Monte Carlo radiative
transfer modeling of the dust emission from SN 2007od implies that up to 4x
10-4Msun of new dust has formed. This is similar to the amounts of dust formed
in other CCSNe such as SNe 1999em, 2004et, and 2006jc.Comment: 35 pages, 6 figures. Accepted for publication in Ap
Atividade enzimática do solo sob diferentes culturas em sistema de Integração Lavoura-Pecuária (ILP).
Observation of light echoes around very young stars
The goal of the paper is to present new results on light echoes from young
stellar objects. Broad band CCD images were obtained over three months at
one-to-two week intervals for the field of NGC 6726, using the large
field-of-view remotely-operated telescope on top of Cerro Burek. We detected
scattered light echoes around two young, low-amplitude, irregular variable
stars. Observations revealed not just one, but multiple light echoes from
brightness pulses of the T Tauri star S CrA and the Herbig Ae/Be star R CrA.
Analysis of S CrA's recurring echoes suggests that the star is located 138 +/-
16 pc from Earth, making these the closest echoes ever detected. The
environment that scatters the stellar light from S CrA is compatible with an
incomplete dust shell or an inclined torus some 10,000 AU in radius and
containing M_{\sun} of dust. The cause of such
concentration at 10,000AU from the star is unknown. It could be the
remnant of the envelope from which the star formed, but the distance of the
cloud is remarkably similar to the nominal distance of the Oort cloud to the
Sun, leading us to also speculate that the dust (or ice) seen around S CrA
might have the same origin as the Solar System Oort cloud.Comment: A&A, in press Received: 16 March 2010 / Accepted: 01 June 201
Identification of distinct subgroups of Sj\uf6gren\u27s disease by cluster analysis based on clinical and biological manifestations: data from the cross-sectional Paris-Saclay and the prospective ASSESS cohorts
\ua9 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: Sj\uf6gren\u27s disease is a heterogenous autoimmune disease with a wide range of symptoms—including dryness, fatigue, and pain—in addition to systemic manifestations and an increased risk of lymphoma. We aimed to identify distinct subgroups of the disease, using cluster analysis based on subjective symptoms and clinical and biological manifestations, and to compare the prognoses of patients in these subgroups. Methods: This study included patients with Sj\uf6gren\u27s disease from two independent cohorts in France: the cross-sectional Paris-Saclay cohort and the prospective Assessment of Systemic Signs and Evolution of Sj\uf6gren\u27s Syndrome (ASSESS) cohort. We first used an unsupervised multiple correspondence analysis to identify clusters within the Paris-Saclay cohort using 26 variables comprising patient-reported symptoms and clinical and biological manifestations. Next, we validated these clusters using patients from the ASSESS cohort. Changes in disease activity (measured by the European Alliance of Associations for Rheumatology [EULAR] Sj\uf6gren\u27s Syndrome Disease Activity Index [ESSDAI]), patient-acceptable symptom state (measured by the EULAR Sj\uf6gren\u27s Syndrome Patient Reported Index [ESSPRI]), and lymphoma incidence during follow-up were compared between clusters. Finally, we compared our clusters with the symptom-based subgroups previously described by Tarn and colleagues. Findings: 534 patients from the Paris-Saclay cohort (502 [94%] women, 32 [6%] men, median age 54 years [IQR 43–64]), recruited between 1999 and 2022, and 395 patients from the ASSESS cohort (370 [94%] women, 25 [6%] men, median age 53 years [43–63]), recruited between 2006 and 2009, were included in this study. In both cohorts, hierarchical cluster analysis revealed three distinct subgroups of patients: those with B-cell active disease and low symptom burden (BALS), those with high systemic disease activity (HSA), and those with low systemic disease activity and high symptom burden (LSAHS). During follow-up in the ASSESS cohort, disease activity and symptom states worsened for patients in the BALS cluster (67 [36%] of 186 patients with ESSPRI score <5 at month 60 vs 92 [49%] of 186 at inclusion; p<0\ub70001). Lymphomas occurred in patients in the BALS cluster (five [3%] of 186 patients; diagnosed a median of 70 months [IQR 42–104] after inclusion) and the HSA cluster (six [4%] of 158 patients; diagnosed 23 months [13–83] after inclusion). All patients from the Paris-Saclay cohort with a history of lymphoma were in the BALS and HSA clusters. This unsupervised clustering classification based on symptoms and clinical and biological manifestations did not correlate with a previous classification based on symptoms only. Interpretation: On the basis of symptoms and clinical and biological manifestations, we identified three distinct subgroups of patients with Sj\uf6gren\u27s disease with different prognoses. Our results suggest that these subgroups represent different heterogeneous pathophysiological disease mechanisms, stages of disease, or both. These findings could be of interest when stratifying patients in future therapeutic trials. Funding: Fondation pour la Recherche M\ue9dicale, French Ministry of Health, French Society of Rheumatology, Innovative Medicines Initiative 2 Joint Undertaking, Medical Research Council UK, and Foundation for Research in Rheumatology
- …