Double ionization in R-matrix theory using a two-electron outer region

We have developed a two-electron outer region for use within R-matrix theory to describe double ionisation processes. The capability of this method is demonstrated for single-photon double ionisation of He in the photon energy region between 80 eV to 180 eV. The cross sections are in agreement with established data. The extended RMT method also provides information on higher-order processes, as demonstrated by the identification of signatures for sequential double ionisation processes involving an intermediate He⁺ state with n=2.

A twist in the tale of γ-ray bursts

An unusually long burst of γ-rays zapped Earth in December 2011, lasting 4 hours. The cause of this burst is now proposed to be a peculiar supernova produced by a spinning magnetic neutron star. See Letter p.189

LSQ14bdq: a type Ic Super-luminous Supernova with a double-peaked light curve

We present data for LSQ14bdq, a hydrogen-poor super-luminous supernova (SLSN) discovered by the La Silla QUEST survey and classified by the Public ESO Spectroscopic Survey of Transient Objects. The spectrum and light curve are very similar to slow-declining SLSNe such as PTF12dam. However, detections within ∼1 day after explosion show a bright and relatively fast initial peak, lasting for ∼15 days, prior to the usual slow rise to maximum light. The broader, main peak can be fit with either central engine or circumstellar interaction models. We discuss the implications of the precursor peak in the context of these models. It is too bright and narrow to be explained as a normal ⁵⁶Ni-powered SN, and we suggest that interaction models may struggle to fit the two peaks simultaneously. We propose that the initial peak may arise from the post-shock cooling of extended stellar material, and reheating by a central engine drives the second peak. In this picture, we show that an explosion energy of ∼2 × 10⁵² erg and a progenitor radius of a few hundred solar radii would be required to power the early emission. The competing engine models involve rapidly spinning magnetars (neutron stars) or fallback onto a central black hole. The prompt energy required may favor the black hole scenario. The bright initial peak may be difficult to reconcile with a compact Wolf-Rayet star as a progenitor since the inferred energies and ejected masses become unphysical.

Efficacy and safety of ivacaftor in patients with cystic fibrosis who have an Arg117His-CFTR mutation: a double-blind, randomised controlled trial

BACKGROUND: Ivacaftor has been previously assessed in patients with cystic fibrosis with Gly551Asp-CFTR or other gating mutations. We assessed ivacaftor in patients with Arg117His-CFTR, a residual function mutation.

METHODS: We did a 24-week, placebo-controlled, double-blind, randomised clinical trial, which enrolled 69 patients with cystic fibrosis aged 6 years and older with Arg117His-CFTR and percentage of predicted forced expiratory volume in 1 s (% predicted FEV1) of at least 40. We randomly assigned eligible patients (1:1) to receive placebo or ivacaftor 150 mg every 12 h for 24 weeks. Randomisation was stratified by age (6-11, 12-17, and ≥18 years) and % predicted FEV1 (<70, ≥70 to ≤90, and >90). The primary outcome was the absolute change from baseline in % predicted FEV1 through week 24. Secondary outcomes included safety and changes in sweat chloride concentrations and Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain scores. An open-label extension enrolled 65 of the patients after washout; after 12 weeks, we did an interim analysis.

FINDINGS: After 24 weeks, the treatment difference in mean absolute change in % predicted FEV1 between ivacaftor (n=34) and placebo (n=35) was 2·1 percentage points (95% CI -1·13 to 5·35; p=0·20). Ivacaftor treatment resulted in significant treatment differences in sweat chloride (-24·0 mmol/L, 95% CI -28·01 to -19·93; p<0·0001) and CFQ-R respiratory domain (8·4, 2·17 to 14·61; p=0·009). In prespecified subgroup analyses, % predicted FEV1 significantly improved with ivacaftor in patients aged 18 years or older (treatment difference vs placebo: 5·0 percentage points, 95% CI 1·15 to 8·78; p=0·01), but not in patients aged 6-11 years (-6·3 percentage points, -11·96 to -0·71; p=0·03). In the extension study, both placebo-to-ivacaftor and ivacaftor-to-ivacaftor groups showed % predicted FEV1 improvement (absolute change from post-washout baseline at week 12: placebo-to-ivacaftor, 5·0 percentage points [p=0·0005]; ivacaftor-to-ivacaftor, 6·0 percentage points [p=0·006]). We did not identify any new safety concerns. The studies are registered with ClinicalTrials.gov (the randomised, placebo-controlled study, number NCT01614457; the open-label extension study, number NCT01707290).

INTERPRETATION: Although this study did not show a significant improvement in % predicted FEV1, ivacaftor did significantly improve sweat chloride and CFQ-R respiratory domain scores and lung function in adult patients with Arg117His-CFTR, indicating that ivacaftor might benefit patients with Arg117His-CFTR who have established disease.

Effect of radium-223 dichloride on symptomatic skeletal events in patients with castration-resistant prostate cancer and bone metastases: results from a phase 3, double-blind, randomised trial

BACKGROUND: Bone metastases frequently cause skeletal events in patients with metastatic castration-resistant prostate cancer. Radium-223 dichloride (radium-223) selectively targets bone metastases with high-energy, short-range α-particles. We assessed the effect of radium-223 compared with placebo in patients with castration-resistant prostate cancer and bone metastases.

METHODS: In this phase 3, double-blind, randomised ALSYMPCA trial, we enrolled patients who had symptomatic castration-resistant prostate cancer with two or more bone metastases and no known visceral metastases, who were receiving best standard of care, and had previously either received or were unsuitable for docetaxel. Patients were stratified by previous docetaxel use, baseline total alkaline phosphatase level, and current bisphosphonate use, then randomly assigned (2:1) to receive either six intravenous injections of radium-223 (50 kBq/kg) or matching placebo; one injection was given every 4 weeks. Randomisation was done with an interactive voice response system, taking into account trial stratification factors. Participants and investigators were masked to treatment assignment. The primary endpoint was overall survival, which has been reported previously. Here we report on time to first symptomatic skeletal event, defined as the use of external beam radiation to relieve bone pain, or occurrence of a new symptomatic pathological fracture (vertebral or non-verterbal), or occurence of spinal cord compression, or tumour-related orthopeadic surgical intervention. All events were required to be clinically apparent and were not assessed by periodic radiological review. Statistical analyses of symptomatic skeletal events were based on the intention-to-treat population. The study has been completed and is registered with ClinicalTrials.gov, number NCT00699751.

FINDINGS: Between June 12, 2008, and Feb 1, 2011, 921 patients were enrolled, of whom 614 (67%) were randomly assigned to receive radium-223 and 307 (33%) placebo. Symptomatic skeletal events occurred in 202 (33%) of 614 patients in the radium-223 group and 116 (38%) of 307 patients in the placebo group. Time to first symptomatic skeletal event was longer with radium-223 than with placebo (median 15·6 months [95% CI 13·5-18·0] vs 9·8 months [7·3-23·7]; hazard ratio [HR]=0·66, 95% CI 0·52-0·83; p=0·00037). The risks of external beam radiation therapy for bone pain (HR 0·67, 95% CI 0·53-0·85) and spinal cord compression (HR=0·52, 95% CI 0·29-0·93) were reduced with radium-233 compared with placebo. Radium-223 treatment did not seem to significantly reduce the risk of symptomatic pathological bone fracture (HR 0·62, 95% CI 0·35-1·09), or the need for tumour-related orthopaedic surgical intervention (HR 0·72, 95% CI 0·28-1·82).

INTERPRETATION: Radium-223 should be considered as a treatment option for patients with castration-resistant prostate cancer and symptomatic bone metastases.

FUNDING: Algeta and Bayer HealthCare Pharmaceuticals.

Assessment of the double-skin façade passive thermal buffer effect.

Double Skin Façades (DSFs) are becoming increasingly popular architecture for commercial office buildings. Although DSFs are widely accepted to have the capacity to offer significant passive benefits and enable low energy building performance, there remains a paucity of knowledge with regard to their operation. Identification of the most determinant architectural parameters of DSFs is the focus of ongoing research. This paper presents an experimental and simulation study of a DSF installed on a commercial building in Dublin, Ireland. The DSF is south facing and acts to buffer the building from winter heat losses, but risks enhancing over-heating on sunny days. The façade is extensively monitored during winter months. Computational Fluid Dynamic (CFD) models are used to simulate the convective operation of the DSF. This research concludes DSFs as suited for passive, low energy architecture in temperature climates such as Ireland but identifies issues requiring attention in DSF design.

Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams

PURPOSE: To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams.

METHODS AND MATERIALS: Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam.

RESULTS: A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci.

CONCLUSIONS: The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions.

Flow Pattern in Compound Channel with Floodplain Double Groyne

The results of an experimental study and velocity analysis of the flow characteristics in the vicinityof a floodplain with two rows of permeable/impermeable groynes in compound channels with oneand two floodplains are presented. A 60% permeable groyne model with three different lengthsrelative to the floodplain width was used. The results showed that double groyne could beconsidered as one groyne (one block) for aspect ratio Sr < 2 (Sr = distance between twosuccessive groynes/groyne length). When Sr > 2, each groyne started to act independently.The velocity reduction was more than 45-52% of the floodplain’s approach velocity compared with30-35% in the case of a single groyne. The significant velocity reduction was located at a distance1.5-2 times the groyne length downstream of the single or the double groynes. Generally, themaximum velocities in the main channel ranged from 1.1 to 1.35 times the original approachingvelocity. The effective groyne relative length and aspect ratio should not to be more than 0.5 and 2,respectively.

Experimental analysis of air flow profiles in a double skin facade in a maritime climate

Glazed Double Skin Facades (DSF) offer the potential to improve the performance of all-glass building skins, common to commercial office buildings in which full facade glazing has almost become the standard. Single skin glazing results in increased heating and cooling costs over opaque walls, due to lower thermal resistance of glass, and the increased impact of solar gain through it. However, the performance benefit of DSF technology continues to be questioned and its operation poorly understood, particularly the nature of airflow through the cavity. This paper deals specifically with the experimental analysis of the air flow characteristics in an automated double skin façade. The benefit of the DSF as a thermal buffer, and to limit overheating is evaluated through analysis of an extensive set of parameters including air and surface temperatures at each level in the DSF, airflow readings in the cavity and at the inlet and outlet, solar and wind data, and analytically derived pressure differentials. The temperature and air-flow are monitored in the cavity of a DSF using wireless sensors and hot wire anemometers respectively. Automated louvre operation and building set-points are monitored via the BMS. Thermal stratification and air flow variation during changing weather conditions are shown to effect the performance of the DSF considerably and hence the energy performance of the building. The relative pressure effects due to buoyancy and wind are analysed and quantified. This research aims to developed and validate models of DSFs in the maritime climate, using multi-season data from experimental monitoring. This extensive experimental study provides data for training and validation of models.

Assessment of DNA double-strand breaks induced by intravascular iodinated contrast media following in vitro irradiation and in vivo, during paediatric cardiac catheterization

Paediatric cardiac catheterizations may result in the administration of substantial amounts of iodinated contrast media and ionizing radiation. The aim of this work was to investigate the effect of iodinated contrast media in combination with in vitro and in vivo X-ray radiation on lymphocyte DNA. Six concentrations of iodine (15, 17.5, 30, 35, 45, and 52.5 mg of iodine per mL blood) represented volumes of iodinated contrast media used in the clinical setting. Blood obtained from healthy volunteers was mixed with iodinated contrast media and exposed to radiation doses commonly used in paediatric cardiac catheterizations (0 mGy, 70 mGy, 140 mGy, 250 mGy and 450 mGy). Control samples contained no iodine. For in vivo experimentation, pre and post blood samples were collected from children undergoing cardiac catheterization, receiving iodine concentrations of up to 51 mg of iodine per mL blood and radiation doses of up to 400 mGy. Fluorescence microscopy was performed to assess γH2AX-foci induction, which corresponded to the number of DNA double-strand breaks. The presence of iodine in vitro resulted in significant increases of DNA double-strand breaks beyond that induced by radiation for ≥17.5 mg/mL iodine to blood. The in vivo effects of contrast media on children undergoing cardiac catheterization resulted in a 19% increase in DNA double-strand breaks in children receiving an average concentration of 19 mg/mL iodine to blood. A larger investigation is required to provide further information of the potential benefit of lowering the amount of iodinated contrast media received during X-ray radiation investigations. 

SN 2011fu: a type IIb supernova with a luminous double-peaked light curve

We present optical and near-infrared observations of the type IIb supernova (SN) 2011fu from a few days to similar to 300 d after explosion. The SN presents a double-peaked light curve (LC) similar to that of SN 1993J, although more luminous and with a longer cooling phase after the primary peak. The spectral evolution is also similar to SN 1993J's, with hydrogen dominating the spectra to similar to 40 d, then helium gaining strength, and nebular emission lines appearing from similar to 60 d post-explosion. The velocities derived from the P-Cygni absorptions are overall similar to those of other type IIb SNe. We have found a strong similarity between the oxygen and magnesium line profiles at late times, which suggests that these lines are forming at the same location within the ejecta. The hydrodynamical modelling of the pseudo-bolometric LC and the observed photospheric velocities suggest that SN 2011fu was the explosion of an extended star (R similar to 450 R-circle dot), in which 1.3 x 10(51) erg of kinetic energy were released and 0.15 M-circle dot of Ni-56 were synthesized. In addition, a better reproduction of the observed early pseudo-bolometric LC is achieved if a more massive H-rich envelope than for other type IIb SNe is considered (0.3 M-circle dot). The hydrodynamical modelling of the LC and the comparison of our late-time spectra with nebular spectral models for type IIb SNe, point to a progenitor for SN 2011fu with a Zero Age Main Sequence (ZAMS) mass of 13-18 M-circle dot.