First Exclusive Measurement of Deeply Virtual Compton Scattering off ^{4}He: Toward the 3D Tomography of Nuclei

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized ^{4}He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling ^{4}He nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only ^{4}He Compton form factor, H_{A}. This first measurement of coherent deeply virtual Compton scattering on the ^{4}He nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

An optimised patient information sheet did not significantly increase recruitment or retention in a falls prevention study: an embedded randomised recruitment trial

Background

Randomised controlled trials are generally regarded as the ‘gold standard’ experimental design to determine the effectiveness of an intervention. Unfortunately, many trials either fail to recruit sufficient numbers of participants, or recruitment takes longer than anticipated. The current embedded trial evaluates the effectiveness of optimised patient information sheets on recruitment of participants in a falls prevention trial.

Methods

A three-arm, embedded randomised methodology trial was conducted within the National Institute for Health Research-funded REducing Falls with ORthoses and a Multifaceted podiatry intervention (REFORM) cohort randomised controlled trial. Routine National Health Service podiatry patients over the age of 65 were randomised to receive either the control patient information sheet (PIS) for the host trial or one of two optimised versions, a bespoke user-tested PIS or a template-developed PIS. The primary outcome was the proportion of patients in each group who went on to be randomised to the host trial.

Results

Six thousand and nine hundred patients were randomised 1:1:1 into the embedded trial. A total of 193 (2.8%) went on to be randomised into the main REFORM trial (control n = 62, template-developed n = 68; bespoke user-tested n = 63). Information sheet allocation did not improve recruitment to the trial (odds ratios for the three pairwise comparisons: template vs control 1.10 (95% CI 0.77–1.56, p = 0.60); user-tested vs control 1.01 (95% CI 0.71–1.45, p = 0.94); and user-tested vs template 0.92 (95% CI 0.65–1.31, p = 0.65)).

Conclusions

This embedded methodology trial has demonstrated limited evidence as to the benefit of using optimised information materials on recruitment and retention rates in the REFORM study.

Trial registration

International Standard Randomised Controlled Trials Number registry, ISRCTN68240461. Registered on 01 July 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1797-7) contains supplementary material, which is available to authorized users.

A randomized, embedded trial of pre-notification of trial participation did not increase recruitment rates to a falls prevention trial

OBJECTIVES

To design and evaluate the effectiveness of a pre-notification leaflet about research to increase recruitment to a randomized controlled trial (RCT).

METHODS

A methodological, two-arm, RCT was conducted, embedded within an existing cohort RCT (REFORM). Participants were randomized for the embedded trial, using a 1:2 ratio (intervention : control) before being randomized for REFORM. Controls received a trial recruitment pack. The intervention group received an additional pre-notification leaflet 2-3 weeks before the recruitment pack. Primary and secondary analyses were conducted using relative risk, the Cox proportional hazards model and incremental cost-effectiveness ratios.

RESULTS

Of the 1436 intervention group participants, 73 (5.1%) were randomized into the REFORM trial compared with 126 (4.4%) of the 2878 control group participants. The associated relative risk (1.16) was not statistically significant [95% confidence interval (CI) 0.88-1.56]. Return rate was not significantly increased (relative risk 1.10, 95% CI 0.92-1.28) nor time to return decreased (hazard ratio: 1.11, 95% CI 0.93-1.33). Incremental cost-effectiveness ratios indicated the intervention may be cost-effective if the true estimate of effect was close to the upper bound of the associated 95% CI.

CONCLUSION

Pre-notification for potential trial participants demonstrated a small difference to randomization (0.7% difference) and return rates (1.1% difference) in favour of the intervention. Results should however be interpreted with caution as CIs for these estimates cross the point of no effect. Nevertheless, this research enhances existing evidence for pre-notification to increase recruitment rates, with further development and assessment of this potentially cost-effective intervention being recommended.

Cohort Randomised Controlled Trial of a Multifaceted Podiatry Intervention for the Prevention of Falls in Older People (The REFORM Trial)

BACKGROUND

Falls are a major cause of morbidity among older people. A multifaceted podiatry intervention may reduce the risk of falling. This study evaluated such an intervention.

DESIGN

Pragmatic cohort randomised controlled trial in England and Ireland. 1010 participants were randomised (493 to the Intervention group and 517 to Usual Care) to either: a podiatry intervention, including foot and ankle exercises, foot orthoses and, if required, new footwear, and a falls prevention leaflet or usual podiatry treatment plus a falls prevention leaflet. The primary outcome was the incidence rate of self-reported falls per participant in the 12 months following randomisation. Secondary outcomes included: proportion of fallers and those reporting multiple falls, time to first fall, fear of falling, Frenchay Activities Index, Geriatric Depression Scale, foot pain, health related quality of life, and cost-effectiveness.

RESULTS

In the primary analysis were 484 (98.2%) intervention and 507 (98.1%) control participants. There was a small, non statistically significant reduction in the incidence rate of falls in the intervention group (adjusted incidence rate ratio 0.88, 95% CI 0.73 to 1.05, p = 0.16). The proportion of participants experiencing a fall was lower (49.7 vs 54.9%, adjusted odds ratio 0.78, 95% CI 0.60 to 1.00, p = 0.05) as was the proportion experiencing two or more falls (27.6% vs 34.6%, adjusted odds ratio 0.69, 95% CI 0.52 to 0.90, p = 0.01). There was an increase (p = 0.02) in foot pain for the intervention group. There were no statistically significant differences in other outcomes. The intervention was more costly but marginally more beneficial in terms of health-related quality of life (mean quality adjusted life year (QALY) difference 0.0129, 95% CI -0.0050 to 0.0314) and had a 65% probability of being cost-effective at a threshold of £30,000 per QALY gained.

CONCLUSION

There was a small reduction in falls. The intervention may be cost-effective.

TRIAL REGISTRATION

ISRCTN ISRCTN68240461.

Implementation of blinded outcome assessment in the Effective Verruca Treatments trial (EverT) - lessons learned

BACKGROUND

Trials using inadequate levels of blinding may report larger effect sizes than blinded studies. It has been suggested that blinded outcome assessment in open trials may in some cases be undertaken by assessments of photographs. The aim of this paper is to explore the effect of using different methods to assess the primary outcome in the EVerT (Effective Verruca Treatments) trial. It also aims to give an overview of the experiences of using digital photographs within the trial.

METHODS

We undertook a secondary analysis to explore the effect of using three different methods to assess the primary outcome in the EVerT trial: assessment of digital photographs by blinded healthcare professionals; blinded healthcare professional assessment at the recruiting site and patient self-report. The verruca clearance rates were calculated using the three different methods of assessment. A Cohen's kappa measure of inter-rater agreement was used to assess the agreement between the methods. We also investigated the experiences of healthcare professionals using digital photographs within the trial.

RESULTS

Digital photographs for 189 out of 240 (79 %) patients in the trial were received for outcome assessment. Of the 189 photographs, 30 (16 %) were uninterpretable. The overall verruca clearance rates were 21 % (43/202,) using the unblinded patient self-reported outcome, 6 % (9/159,) using blinded assessment of digital photographs and 14 % (30/210,) using blinded outcome assessment at the site.

CONCLUSIONS

Despite differences in the clearance rates found using different methods of outcome assessment, this did not change the original conclusion of the trial, that there is no evidence of a difference in effectiveness between cryotherapy and salicylic acid. Future trials using digital photographs should consider individual training needs at sites and have a backup method of assessment agreed a priori.

TRIAL REGISTRATION

ISRCTN Registry ISRCTN18994246.

Safety, tolerability, efficacy and pharmacodynamics of the selective JAK1 inhibitor GSK2586184 in patients with systemic lupus erythematosus

We aimed to evaluate the pharmacodynamics, efficacy, safety and tolerability of the JAK1 inhibitor GSK2586184 in adults with systemic lupus erythematosus (SLE). In this adaptive, randomized, double-blind, placebo-controlled study, patients received oral GSK2586184 50-400 mg, or placebo twice daily for 12 weeks. Primary endpoints included interferon-mediated messenger RNA transcription over time, changes in Safety of Estrogen in Lupus National Assessment-SLE Disease Activity Index score, and number/severity of adverse events. A pre-specified interim analysis was performed when ≥ 5 patients per group completed 2 weeks of treatment. In total, 84-92% of patients were high baseline expressors of the interferon transcriptional biomarkers evaluated. At interim analysis, GSK2586184 showed no significant effect on mean interferon transcriptional biomarker expression (all panels). The study was declared futile and recruitment was halted at 50 patients. Shortly thereafter, significant safety data were identified, including elevated liver enzymes in six patients (one confirmed and one suspected case of Drug Reaction with Eosinophilia and Systemic Symptoms), leading to immediate dosing cessation. Safety of Estrogen in Lupus National Assessment-SLE Disease Activity Index scores were not analysed due to the small number of patients completing the study. The study futility and safety data described for GSK2586184 do not support further evaluation in patients with SLE. Study identifiers: GSK Study JAK115919; ClinicalTrials.gov identifier: NCT01777256.

Interference Effect between ϕ and Λ(1520) Production Channels in the γp→K^{+}K^{-}p Reaction near Threshold

The ϕ-Λ(1520) interference effect in the γp→K^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between ϕ and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1  GeV bump structure in forward differential cross sections for ϕ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.

Subcutaneous Administration of Otelixizumab is Limited by Injection Site Reactions: Results of an Exploratory Study in Type 1 Diabetes Mellitus Patients

Targeting CD3 antigens on human T lymphocytes with monoclonal antibodies has been shown to reduce the rate of decline of C-peptides in recent-onset type 1 diabetes mellitus patients. However, effective doses are associated with infusion reactions typical of "cytokine release syndrome" and appear to be dose-limiting when administered as short-duration infusions. A possible alternative approach, which may reduce the rate of T cell activation and consequent systemic cytokine release, is to inject subcutaneously. We investigated single- and repeat-dose subcutaneous administration of the anti-CD3 monoclonal antibody otelixizumab in small cohorts of patients with type 1 diabetes. Transient reductions in free or unbound CD3 antigen on CD4+ and CD8+ cells and absolute lymphocyte count were observed in the blood of these patients during treatment, consistent with the known mechanism of action of otelixizumab and other anti-CD3 monoclonal antibodies. This was despite the very low systemic exposure of antibodies measured during the same time period. With the exception of sporadic headaches, other symptoms associated with cytokine release syndrome, such as fever, nausea, vomiting, myalgia, and arthralgia, were absent in treated patients. However, treatment-related injection site reactions were consistently observed. The reactions were erythematous and their sizes were dose-dependent; in some cases, reactions persisted for up to 2 weeks following the start of treatment. While patients responded well to topical corticosteroid treatment and prophylaxis reduced the intensity of injection site reactions, the reactions were considered dose-limiting and higher doses were not investigated.

Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions

Unpolarized and beam-polarized fourfold cross sections (d^{4}σ/dQ^{2}dx_{B}dtdϕ) for the ep→e^{'}p^{'}γ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 (Q^{2},x_{B},t) bins over the widest phase space ever explored in the valence-quark region. Several models of generalized parton distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD H, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton form factors, these results support the model predictions of a larger nucleon size at lower quark-momentum fraction x_{B}.

Towards a resolution of the proton form factor problem: new electron and positron scattering data

There is a significant discrepancy between the values of the proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of G(E)(p) from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ϵ) and momentum transfer (Q(2)) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ϵ at Q(2)=1.45  GeV(2). This measurement is consistent with the size of the form factor discrepancy at Q(2)≈1.75  GeV(2) and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2-3  GeV(2).

The REFORM study protocol: a cohort randomised controlled trial of a multifaceted podiatry intervention for the prevention of falls in older people

INTRODUCTION

Falls and fall-related injuries are a serious cause of morbidity and cost to society. Foot problems and inappropriate footwear may increase the risk of falls; therefore podiatric interventions may play a role in reducing falls. Two Cochrane systematic reviews identified only one study of a podiatry intervention aimed to reduce falls, which was undertaken in Australia. The REFORM trial aims to evaluate the clinical and cost-effectiveness of a multifaceted podiatry intervention in reducing falls in people aged 65 years and over in a UK and Irish setting.

METHODS AND ANALYSIS

This multicentre, cohort randomised controlled trial will recruit 2600 participants from routine podiatry clinics in the UK and Ireland to the REFORM cohort. In order to detect a 10% point reduction in falls from 50% to 40%, with 80% power 890 participants will be randomised to receive routine podiatry care and a falls prevention leaflet or routine podiatry care, a falls prevention leaflet and a multifaceted podiatry intervention. The primary outcome is rate of falls (falls/person/time) over 12 months assessed by patient self-report falls diary. Secondary self-report outcome measures include: the proportion of single and multiple fallers and time to first fall over a 12-month period; Short Falls Efficacy Scale-International; fear of falling in the past 4 weeks; Frenchay Activities Index; fracture rate; Geriatric Depression Scale; EuroQoL-five dimensional scale 3-L; health service utilisation at 6 and 12 months. A qualitative study will examine the acceptability of the package of care to participants and podiatrists.

ETHICS AND DISSEMINATION

The trial has received a favourable opinion from the East of England-Cambridge East Research Ethics Committee and Galway Research Ethics Committee. The trial results will be published in peer-reviewed journals and at conference presentations.

TRIAL REGISTRATION NUMBER

Current Controlled Trials ISRCTN68240461 assigned 01/07/2011.

Chemical defense of a rove beetle (Creophilus maxillosus)

The abdominal defensive glands ofC. maxillosus secrete a mixture (70μg/beetle) of isoamyl alcohol (I), isoamyl acetate (II), iridodial (III), actinidine (IV), dihydronepetalactone (VE), and (E)-8-oxocitronellyl acetate (X). When disturbed, the beetle everts the glands and revolves the abdomen so as to wipe the glands against the offending agent. Fecal fluid is commonly emitted at the same time and may become added to the glandular material. Ants (Formica exsectoides) are effectively fended off by the beetle and were shown in bioassays (Monomorium destructor) to be repelled by the four major components of the secretion (II, III, X, VE); the principal component (VE) was the most active. Some anatomical features of the glands are described.

Hard two-body photodisintegration of 3He

We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

The effect of patients' preference on outcome in the EVerT cryotherapy versus salicylic acid for the treatment of plantar warts (verruca) trial

BACKGROUND

Randomised controlled trials are widely accepted as the gold standard method to evaluate medical interventions, but they are still open to bias. One such bias is the effect of patient's preference on outcome measures. The aims of this study were to examine whether patients' treatment preference affected clearance of plantar warts and explore whether there were any associations between patients' treatment preference and baseline variables in the EverT trial.

METHODS

Two hundred and forty patients were recruited from University podiatry schools, NHS podiatry clinics and primary care. Patients were aged 12 years and over and had at least one plantar wart which was suitable for treatment with salicylic acid and cryotherapy. Patients were asked their treatment preference prior to randomisation. The Kruskal-Wallis test was performed to test the association between preference group and continuous baseline variables. The Fisher's exact test was performed to test the association between preference group and categorical baseline variables. A logistic regression analysis was undertaken with verruca clearance (yes or no) as the dependent variable and treatment, age, type of verruca, previous treatment, treatment preference as independent variables. Two analyses were undertaken, one using the health professional reported outcome and one using the patient's self reported outcomes. Data on whether the patient found it necessary to stop the treatment to which they had been allocated and whether they started another treatment were summarised by treatment group.

RESULTS

Pre-randomisation preferences were: 10% for salicylic acid; 42% for cryotherapy and 48% no treatment preference. There was no evidence of an association between treatment preference group and either patient (p=0.95) or healthcare professional (p=0.46) reported verruca clearance rates. There was no evidence of an association between preference group and any of the baseline variables except gender, with more females expressing a preference for salicylic acid (p=0.004). There was no evidence that the number of times salicylic acid was applied was different between the preference groups at one week (p=0.89) or at three weeks (p=0.24). Similarly, for the number of clinic visits for cryotherapy (p=0.71) CONCLUSIONS: This secondary analysis showed no evidence to suggest that patients' baseline preferences affected verruca clearance rates or adherence with the treatment.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN18994246 and National Research Register N0484189151.

Measurement of exclusive π(0) electroproduction structure functions and their relationship to transverse generalized parton distributions

Exclusive π(0) electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q(2), x(B), t, and ϕ(π), in the Q(2) range from 1.0 to 4.6  GeV(2), -t up to 2  GeV(2), and x(B) from 0.1 to 0.58. Structure functions σ(T)+ϵσ(L), σ(TT), and σ(LT) were extracted as functions of t for each of 17 combinations of Q(2) and x(B). The data were compared directly with two handbag-based calculations including both longitudinal and transversity generalized parton distributions (GPDs). Inclusion of only longitudinal GPDs very strongly underestimates σ(T)+ϵσ(L) and fails to account for σ(TT) and σ(LT), while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity-flip and helicity nonflip processes. The results confirm that exclusive π(0) electroproduction offers direct experimental access to the transversity GPDs.

Measurement of the neutron F2 structure function via spectator tagging with CLAS

We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲100 MeV/c and their angles to ≳100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65<Q(2)<4.52 GeV(2), with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio F(2)(n)/F(2)(p) at 0.2≲x≲0.8 with little uncertainty due to nuclear effects.