Context. Phase-mask coronagraphs can be seen as linear systems that spatially redistribute in the pupil plane the energy collected by the telescope. Most of the on-axis light must ideally be rejected ...outside the aperture so as to be blocked with a Lyot stop, while almost all of the off-axis light must go through it. The unobstructed circular apertures of off-axis telescopes make this possible but all of the major telescopes are on-axis, however, and the performance of these coronagraphs is dramatically reduced by their central obstructions. Aims. Their performance can be restored by using an additional optimally designed apodizer that changes the amplitude in the first pupil plane so that the on-axis light is rejected outside the obstructed aperture of the on-axis telescope. Methods. An apodizer is assumed to be located in a pupil plane, a phase mask in a subsequent image plane, and a Lyot stop in a reimaged pupil plane. The numerical optimization model is built by maximizing the apodizer’s transmission while setting constraints on the extremum values of the electric field that the Lyot stop does not block. The coronagraphic image is compared to what a non-apodized phase mask coronagraph provides and an analysis is made of the trade-offs that exist between the transmission of the apodizer and the properties of the Lyot stop. Results. The existence of a solution and the transmission of the mask depend on the geometries of the aperture and of the Lyot stop, and on the constraints that are set on the on-axis attenuation. The system’s throughput is a concave function of the Lyot stop transmission. In the case of a VLT-like aperture, optimal apodizers with a transmission of 16% to 92% associated with a four-quadrant phase mask provide contrast as low as a few 10-10 at 1 λ/D from the star. The system’s maximum throughput is about 64% for an apodizer with an 88% transmission and a Lyot stop with a 69% transmission. It is shown that optimizing apodizers for a vortex phase mask requires computation times much longer than in the previous case, and no result is presented for this mask. Conclusions. It is demonstrated that apodizers can be successfully optimized to allow phase mask coronagraphs to be used with the full aperture of on-axis telescopes while delivering contrast as low as, or even lower than what they could provide by themselves with off-axis telescopes.
In the context of exoplanet direct detection and characterization, where high-contrast imaging is mandatory, we present fully optimized two-dimensional pupil apodizations for which no specific ...geometric constraints are put on the pupil plane apodization, apart from the shape of the aperture itself. Masks for circular and segmented apertures are displayed, with and without a central obstruction and spiders. We can now optimize apodizers for any aperture shape, and examples of optimal masks are shown for the Subaru telescope, the Space Infrared telescope for Cosmology and Astrophysics (SPICA) and the James Webb Space Telescope (JWST). Several high-contrast regions are considered with different sizes, positions, shapes and contrasts. It is interesting to note that all the masks that result from these optimizations tend to have a binary transmission profile.
With a clear circular aperture, the vortex coronagraph perfectly cancels an on-axis point source and offers a 0.9 or 1.75lambda/D inner working angle for topological charge 2 or 4, respectively. ...Current and near-future large telescopes are on-axis, however, and the diffraction effects of the central obscuration, and the secondary supports are strong enough to prevent the detection of companions 10-3 --10-5 as bright as, or fainter than, their host star. Recent advances show that a ring apodizer can restore the performance of this coronagraph by compensating for the diffraction effects of a circular central obscuration in a 1D modeling of the pupil. Our aim is to extend this work and design optimal apodizers for arbitrary apertures in 2D in order to tackle the diffraction effects of the spiders and other noncircular artifacts in the pupil. The results presented in this paper show that high contrast at small inner working angles can be obtained with a vortex coronagraph for on-axis telescopes, in spite of the presence of a secondary mirror and its secondary support structures.
We aimed to evaluate whether the administration of riboflavin to septic animals reduces inflammation, oxidative stress, organ dysfunction, and mortality. C57BL/6 mice, 6-8 weeks old, were allocated ...to the study group (polymicrobial sepsis induced by cecal ligation and puncture (CLP) + antibiotic + iv riboflavin), control (CLP + antibiotic + iv saline), or naïve (non-operated controls). Serum concentrations of alanine aminotransferase (ALT), creatine kinase-MB (CK-MB), urea, and creatinine, and markers of inflammation interleukin (IL)-6, tumor necrosis factor (TNF)-α, keratinocyte-derived chemokine (KC), and macrophage inflammatory protein (MIP)-2), and oxidative stress (malondialdehyde (MDA) were measured 12 h after the experiment. Animal survival rates were calculated after 7 days. Means between groups were compared using linear regression models adjusted under the Bayesian approach. No significant difference was observed between control and study groups in serum concentrations of IL-6 (95% credible interval) (-0.35 to 0.44), TNF-α (-15.7 to 99.1), KC (-0.13 to 0.05), MIP-2 (-0.84 to 0.06), MDA (-1.25 to 2.53), or ALT (-6.6 to 11.5). Serum concentrations of CK-MB (-145.1 to -30.1), urea (-114.7 to -15.1), and creatinine (-1.14 to -0.01) were higher in the study group. Survival was similar in both groups (P=0.8). Therefore, the use of riboflavin in mice undergoing sepsis induced by CLP did not reduce inflammation, oxidative stress, organ dysfunction, or mortality compared with placebo.
Context.
The direct detection of faint exoplanets with high-contrast instruments can be boosted by combining it with high spectral resolution. For integral field spectrographs yielding hyperspectral ...data, this means that the majority of the field of view consists of diffracted starlight spectra and a spatially localized planet. Observation analysis usually relies on classic cross-correlation with theoretical spectra, maximized at the position and with the properties of the planet. In a purely blind-search context, this supervised strategy can be biased with model mismatch and/or be computationally inefficient.
Aims.
Using an approach that is inspired by the analysis of hyperspectral data within the remote-sensing community, we aim to propose an alternative to cross-correlation that is fully data-driven, which decomposes the data into a set of individual spectra and their corresponding spatial distributions. This strategy is called spectral unmixing.
Methods.
We used an orthogonal subspace projection to identify the most distinct spectra in the field of view. Their spatial distribution maps were then obtained by inverting the data. These spectra were then used to break the original hyperspectral images into their corresponding spatial distribution maps via non-negative least squares. A matched filter with the instrument point-spread function (or visual inspection) was then used to detect the planet on one of the maps. The performance of our method was evaluated and compared with a cross-correlation using simulated hyperspectral data with medium resolution from the ELT/HARMONI integral field spectrograph.
Results.
We show that spectral unmixing effectively leads to a planet detection solely based on spectral dissimilarities at significantly reduced computational cost. The extracted spectrum holds significant signatures of the planet while being not perfectly separated from residual starlight. The sensitivity of the supervised cross-correlation is three to four times higher than with unsupervised spectral unmixing, the gap is biased toward the former because the injected and correlated spectrum match perfectly. The algorithm was furthermore vetted on real data obtained with VLT/SINFONI of the
β
Pictoris system. This led to the detection of
β
Pictoris b with a signal-to-noise ratio of 28.5.
Conclusions.
Spectral unmixing is a viable alternative strategy to a cross-correlation to search for and characterize exoplanets in hyperspectral data in a purely data-driven approach. The advent of large data from the forthcoming IFS on board
JWST
and future ELTs motivates further algorithm development along this path.
Combining high-contrast imaging with medium-resolution spectroscopy has been shown to significantly boost the direct detection of exoplanets. HARMONI, one of the first-light instruments to be mounted ...on ESO’s future extremely large telescope (ELT), will be equipped with a single-conjugated adaptive optics system to reach the diffraction limit of the ELT in the
H
and
K
bands, a high-contrast module dedicated to exoplanet imaging, and a medium-resolution (up to
R
= 17 000) optical and near-infrared integral field spectrograph. When combined, these systems will provide unprecedented contrast limits at separations between 50 and 400 mas. This paper is aimed at estimating the capabilities of the HARMONI high-contrast module for the direct detection of young giant exoplanets. We use an end-to-end model of the instrument to simulate high-contrast observations performed with HARMONI, based on realistic observing scenarios and conditions. We then analyze these data with the so-called “molecule mapping” technique combined with a matched-filter approach in order to disentangle companions from the host star and tellurics and to increase the signal-to-noise ratio (S/N) of the planetary signal. We detected planets above 5
σ
at contrasts up to 16 mag and separations down to 75 mas in several spectral configurations of the instrument. We show that molecule mapping allows for the detection of companions up to 2.5 mag fainter compared to state-of-the-art high-contrast imaging techniques based on angular differential imaging. We also demonstrate that the performance is not strongly affected by the spectral type of the host star and we show that we are able to reach close sensitivities for the best three quartiles of observing conditions at Armazones, which means that HARMONI could be used in near-critical observations during 60 to 70% of telescope time at the ELT. Finally, we simulated planets from population synthesis models to further explore the parameter space that HARMONI and its high-contrast module will open up and compare this to the current high-contrast instrumentation.
The goal of this study was to examine the prevalence, assessment and management of pediatric pain in a public teaching hospital. The study sample consisted of 121 inpatients (70 infants, 36 children, ...and 15 adolescents), their families, 40 physicians, and 43 nurses. All participants were interviewed except infants and children who could not communicate due to their clinical status. The interview included open-ended questions concerning the inpatients' pain symptoms during the 24 h preceding data collection, as well as pain assessment and pharmacological/non-pharmacological management of pain. The data were obtained from 100% of the eligible inpatients. Thirty-four children/adolescents (28%) answered the questionnaire and for the other 72% (unable to communicate), the family/health professional caregivers reported pain. Among these 34 persons, 20 children/adolescents reported pain, 68% of whom reported that they received pharmacological intervention for pain relief. Eighty-two family caregivers were available on the day of data collection. Of these, 40 family caregivers (49%) had observed their child's pain response. In addition, 74% reported that the inpatients received pharmacological management. Physicians reported that only 38% of the inpatients exhibited pain signs, which were predominantly acute pain detected during clinical procedures. They reported that 66% of patients received pharmacological intervention. The nurses reported pain signs in 50% of the inpatients, which were detected during clinical procedures. The nurses reported that pain was managed in 78% of inpatients by using pharmacological and/or non-pharmacological interventions. The findings provide evidence of the high prevalence of pain in pediatric inpatients and the under-recognition of pain by health professionals.
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) primarily affects small vessels. Large-vessel involvement (LVI) is rare. We aimed to describe the characteristics of LVI, to ...identify associated risk factors, and to describe its therapeutic management.
This multicenter case-control (1:2) study included patients with AAV according to the ACR/EULAR classification and LVI as defined by the Chapel Hill nomenclature, together with controls matched for age, sex, and AAV type.
We included 26 patients, 15 (58 %) of whom were men, with a mean age of 56.0 ± 17.1 years. The patients had granulomatosis with polyangiitis (n = 20), or microscopic polyangiitis (n = 6). The affected vessels included the aorta (n = 18; 69 %) supra-aortic trunks (n = 9; 35 %), lower-limb arteries (n = 5; 19 %), mesenteric arteries (n = 5; 19 %), renal arteries (n = 4; 15 %), and upper-limb arteries (n = 2; 8 %). Imaging showed wall thickening (n = 10; 38 %), perivascular inflammation (n = 8; 31 %), aneurysms (n = 5; 19 %), and stenosis (n = 4; 15 %). Comparisons with the control group revealed that LVI was significantly associated with neurological manifestations (OR=3.23 95 % CI: 1.11–10.01, p = 0.03), but not with cardiovascular risk factors (OR=0.70 95 % CI: 0.23–2.21, p = 0.60), or AAV relapse (OR=2.01 95 % CI: 0.70–5.88, p = 0.16). All patients received corticosteroids, in combination with an immunosuppressant in 24 (92 %), mostly cyclophosphamide (n = 10, 38 %) or rituximab (n = 9, 35 %).
Regardless of distinctions based on vessel size, clinicians should consider LVI as a potential manifestation of AAV, with the aorta commonly affected. The risk of developing LVI appears to be greater for clinical phenotypes of AAV with neurological involvement. Standard AAV treatment can be used to manage LVI.
Summary
Background
Merkel cell polyomavirus (MCPyV) is the main aetiological agent of Merkel cell carcinoma (MCC). Serum antibodies against the major MCPyV capsid protein (VP1) are detected in the ...general population, whereas antibodies against MCPyV oncoproteins (T antigens) have been reported specifically in patients with MCC.
Objectives
The primary aim was to assess whether detection of serum antibodies against MCPyV proteins at baseline was associated with disease outcome in patients with MCC. The secondary aim was to establish whether evolution of these antibodies during follow‐up was associated with the course of the disease.
Methods
Serum T‐antigen and VP1 antibodies were assessed by enzyme‐linked immunosorbent assay using recombinant proteins in a cohort of 143 patients with MCC, including 84 patients with serum samples available at baseline.
Results
Low titres of VP1 antibodies at baseline (< 10 000) were significantly and independently associated with increased risk of recurrence hazard ratio (HR) 2·71, 95% confidence interval (CI) 1·13–6·53, P = 0·026 and death (HR 3·74, 95% CI 1·53–9·18, P = 0·004), whereas T‐antigen antibodies were not found to be associated with outcome. VP1 antibodies did not differ between patients in remission and those with recurrence or progression during follow‐up. However, T‐antigen antibodies were more frequently detected in patients with recurrence or progression at 12 months (P = 0·020) and 24 months (P = 0·016) after diagnosis.
Conclusions
VP1 antibodies constitute a prognostic marker at baseline, whereas T‐antigen antibodies constitute a marker of disease recurrence or progression if detected > 12 months after diagnosis.
What's already known about this topic?
Antibodies against the Merkel cell polyomavirus major capsid VP1 protein are reported to be associated with recurrence in patients with Merkel cell carcinoma, but any association with mortality is unknown.
Antibodies directed against T antigens are reported to be associated with disease progression, but their prognostic value is unclear.
What does this study add?
T‐antigen antibodies at baseline in patients with Merkel cell carcinoma were not associated with outcome.
Antibodies against VP1 at baseline were associated with both recurrence and mortality.
Linked Comment: Singh and Calonje. Br J Dermatol 2016; 174:715–716.
Summary
Neutrophilic eccrine hidradenitis (NEH) is a rare neutrophilic dermatosis, first described in patients undergoing chemotherapy for a malignant haemopathy. It has polymorphous clinical ...features and the association of both clinical and histological features is necessary to make a diagnosis. We report the first two cases of NEH in patients treated with a BRAF inhibitor (BRAFi), either dabrafenib or vemurafenib, for a stage IV metastatic melanoma. Disseminated erythematous plaques associated with fever and polyarthralgia occurred early after the initiation of treatment and were badly tolerated. Histological analyses confirmed the diagnosis of NEH. Symptoms disappeared a few days after the cessation of treatment and introduction of topical steroids. The replacement of one BRAFi with another is a therapeutic alternative as it is not necessarily associated with a relapse of NEH. NEH can be added to the spectrum of neutrophilic dermatoses induced by BRAFis. It occurs earlier (3–4 days) than previously described drug‐induced NEH (9–12 days) and may be an earlier stage of eccrine squamous syringometaplasia, which has already been reported in the context of BRAFi‐treated patients.
What's already known about this topic?
Cutaneous adverse events are frequent with BRAF inhibitors, including cases of neutrophilic dermatoses.
Neutrophilic eccrine hidradenitis is a neutrophilic dermatosis occurring mostly in patients treated with chemotherapy for a malignant haemopathy.
What does this study add?
Neutrophilic eccrine hidradenitis can be added to the spectrum of neutrophilic dermatoses induced by BRAF inhibitors.
Replacing one BRAF inhibitor with another is a therapeutic option, as it is not necessarily associated with a relapse of the neutrophilic eccrine hidradenitis.
Linked Comment: Basu. Br J Dermatol 2017; 176:1443–1444
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