Neutron capture cross section measurements of 241Am at the n_TOF facility

Neutron capture on 241Am plays an important role in the nuclear energy production and also provides valuable information for the improvement of nuclear models and the statistical interpretation of the nuclear properties. A new experiment to measure the 241Am(n, γ) cross section in the thermal region and the first few resonances below 10 eV has been carried out at EAR2 of the n_TOF facility at CERN. Three neutron-insensitive C6D6 detectors have been used to measure the neutron-capture gamma cascade as a function of the neutron time of flight, and then deduce the neutron capture yield. Preliminary results will be presented and compared with previously obtained results at the same facility in EAR1. In EAR1 the gamma-ray background at thermal energies was about 90% of the signal while in EAR2 is up to a 25 factor much more favorable signal to noise ratio. We also extended the low energy limit down to subthermal energies. This measurement will allow a comparison with neutron capture measurements conducted at reactors and using a different experimental technique.

Study of the neutron-induced fission cross section of 237Np at CERN's n_TOF facility over a wide energy range

Neutron-induced fission cross sections of isotopes involved in the nuclear fuel cycle are vital for the design and safe operation of advanced nuclear systems. Such experimental data can also provide additional constraints for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of fission models. In the present work, the 237Np(n,f) cross section was studied at the EAR2 vertical beam-line at CERN's n_TOF facility, over a wide range of neutron energies, from meV to MeV, using the time-of-flight technique and a set-up based on Micromegas detectors, in an attempt to provide accurate experimental data. Preliminary results in the 200 keV – 14 MeV neutron energy range as well as the experimental procedure, including a description of the facility and the data handling and analysis, will be presented.

Accurate measurement of the standard 235U(n,f) cross section from thermal to 170 keV neutron energy

An accurate measurement of the 235U(n,f) cross section from thermal to 170 keV of neutron energy has recently been performed at n_TOF facility at CERN using 6Li(n,t)4He and 10B(n,α)7Li as references. This measurement has been carried out in order to investigate a possible overestimation of the 235U fission cross section evaluation provided by most recent libraries between 10 and 30 keV. A custom experimental apparatus based on in-beam silicon detectors has been used, and a Monte Carlo simulation in GEANT4 has been employed to characterize the setup and calculate detectors efficiency. The results evidenced the presence of an overestimation in the interval between 9 and 18 keV and the new data may be used to decrease the uncertainty of 235U(n,f) cross section in the keV region.

Light Dark Matter Search with Ionization Signals in XENON1T

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4  keV_{ee}, we observe <1  event/(tonne day keV_{ee}), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m_{χ} within 3-6  GeV/c^{2}, DM-electron scattering for m_{χ}>30  MeV/c^{2}, and absorption of dark photons and axionlike particles for m_{χ} within 0.186-1  keV/c^{2}.

Application of automated electron microscopy imaging and machine learning to characterise and quantify nanoparticle dispersion in aqueous media

For many nanoparticle applications it is important to understand dispersion in liquids. For nanomedicinal and nanotoxicological research this is complicated by the often complex nature of the biological dispersant and ultimately this leads to severe limitations in the analysis of the nanoparticle dispersion by light scattering techniques. Here we present an alternative analysis and associated workflow which utilises electron microscopy. The need to collect large, statistically relevant datasets by imaging vacuum dried, plunge frozen aliquots of suspension was accomplished by developing an automated STEM imaging protocol implemented in an SEM fitted with a transmission detector. Automated analysis of images of agglomerates was achieved by machine learning using two free open‐source software tools: CellProfiler and ilastik. The specific results and overall workflow described enable accurate nanoparticle agglomerate analysis of particles suspended in aqueous media containing other potential confounding components such as salts, vitamins and proteins.

Lay Description

In order to further advance studies in both nanomedicine and nanotoxicology, we need to continue to understand the dispersion of nanoparticles in biological fluids. These biological environments often contain a number of components such as salts, vitamins and proteins which can lead to difficulties when using traditional techniques to monitor dispersion. Here we present an alternative analysis which utilises electron microscopy. In order to use this approach statistically relevant large image datasets were collected from appropriately prepared samples of nanoparticle suspensions by implementing an automated imaging protocol. Automated analysis of these images was achieved through machine learning using two readily accessible freeware; CellProfiler and ilastik. The workflow presented enables accurate nanoparticle dispersion analysis of particles suspended in more complex biological media.

Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.

Impaired enhancement of insulin action in cultured skeletal muscle cells from insulin resistant type 2 diabetic patients in response to contraction using electrical pulse stimulation

AIMS

Skeletal muscle insulin resistance is a characteristic feature of type 2 diabetes. The aim of this study was to examine the effect of contraction on insulin action using electrical pulse stimulation (EPS) in cultured skeletal muscle cells from insulin resistant type 2 diabetic patients.

METHODS

Skeletal muscle cell cultures were established from 6 insulin resistant type 2 diabetic subjects and age and BMI matched non-diabetic control subjects. Day 7 differentiated myotubes were treated with or without EPS for 16 h, after which glucose uptake and AS160 phosphorylation were measured in the presence or absence of insulin.

RESULTS

In control myotubes, EPS resulted in increased phosphorylation of AMPKThr¹⁷² (vs no EPS; p < 0.01), and this was associated with increased glucose uptake (p < 0.05). Insulin in the absence of EPS increased glucose uptake and AS160Thr⁶⁴² phosphorylation, and both effects were significantly enhanced by prior EPS. In the absence of EPS, AMPK activation was significantly increased (p < 0.01) in the diabetic vs control myotubes. Despite a comparable degree of AMPK activation following EPS, the action of insulin on glucose uptake (p < 0.05) and AS160Thr⁶⁴² phosphorylation (p < 0.001) was decreased in the diabetic vs control myotubes.

CONCLUSION

EPS mediated AMPK activation enhances the effect of insulin on glucose uptake and AS160Thr⁶⁴² phosphorylation in control myotubes replicating key metabolic benefits of exercise on insulin action in man. Conversely, insulin mediated glucose uptake and AS160Thr⁶⁴² phosphorylation remain significantly decreased in diabetic vs control myotubes despite a comparable degree of AMPK activation following EPS.

Health-related behaviours in a remote Indigenous population with Type 2 diabetes: a Central Australian primary care survey in the Telehealth Eye and Associated Medical Services Network [TEAMSnet] project

AIM

There is a wealth of data concerning the health behaviours of Indigenous Australians, but the health behaviours of Indigenous Australians with diabetes are not systematically documented. At the clinical level, understanding a person's health behaviours can help identify and address barriers to diabetes care and promote good clinical outcomes.

METHODS

We used a novel survey tool to systematically collect health behaviour data on Smoking, Nutrition, Alcohol consumption, Physical activity and Emotional well-being (SNAPE) from Indigenous Australians with Type 2 diabetes in a remote primary care setting in Alice Springs.

RESULTS

At least one of the five surveys in the SNAPE tool was completed by 210 participants: 30% male, mean age 52.6 years (range 22.9 - 87.4). Fifty per cent of men and 23% of women were current smokers (P < 0.001). None of the participants reported an adequate intake of vegetables. Only 9.6% reported an adequate fruit intake. Some 49% of men and 32% of women consumed alcohol in the past year (P = 0.022), and 46% of drinkers were considered high-risk or likely-dependent drinkers. On average, participants walked 10 min or more at a time 6.0 days a week and spent 4.8 h sitting on a weekday. Mean adapted Patient Health Questionnaire 9 score was 4.61, with 34% of participants having mild depressive symptoms and 11% having moderate-severe depressive symptoms.

CONCLUSIONS

Our SNAPE survey tool results present a high-risk, disadvantaged Indigenous population with Type 2 diabetes. More resources will be needed to sustainably implement interventions with the goal of improving health behaviours and subsequent long-term health.

Identifying Patients Experiencing Homelessness in an Electronic Health Record and Assessing Qualification for Medical Respite: A Five-Year Retrospective Review

Our team developed a transitional care and medical respite program for people experiencing homelessness and designed a retrospective chart review study to more fully understand the unique needs of this population. Using four independent techniques, we identified individuals (N=1,656) who were experiencing homelessness during at least one hospital encounter (emergency department and/or in-patient admission) in a teaching hospital in the Southeastern United States over a five-year period. Data were manually abstracted from a random sample of patients to determine which patient encounters would or would not have qualified for medical respite if it had been available at the time. This article reports the methods used to identify people experiencing homelessness in the electronic health record, the data abstraction process, the cohort description, and the primary reasons patients would not have qualified for the medical respite program.

Diabetes care in remote Australia: the antenatal, postpartum and inter-pregnancy period

BACKGROUND

Aboriginal and Torres Strait Islander women experience high rates of diabetes in pregnancy (DIP), contributing to health risks for mother and infant, and the intergenerational cycle of diabetes. By enhancing diabetes management during pregnancy, postpartum and the interval between pregnancies, the DIP Partnership aims to improve health outcomes and reduce risks early in the life-course. We describe a mixed methods formative study of health professional's perspectives of antenatal and post-partum diabetes screening and management, including enablers and barriers to care.

METHODS

Health professionals involved in providing diabetes care in pregnancy, from a range of health services across the Northern Territory, completed the survey (n = 82) and/or took part in interviews and/or focus groups (n = 62).

RESULTS

Qualitative findings highlighted factors influencing the delivery of care as reported by health professionals, including: whose responsibility it is, access to care, the baby is the focus and pre-conception care. The main challenges were related to: disjointed systems and confusion around whose role it is to provide follow-up care beyond six weeks post-partum. Quantitative findings indicated that the majority of health professionals reported confidence in their own skills to manage women in the antenatal period (62%, 40/79) and slightly lower rates of confidence in the postpartum interval (57%, 33/58).

CONCLUSION

These findings regarding whose role it is to provide postpartum care, along with opportunities to improve communication pathways and follow up care have informed the design of a complex health intervention to improve health systems and the provision of DIP related care.

P5252Can functional MR imaging supersede angiography? An audit of stress cardiac MRI outcomes compared those seen in the CE-MARC trials

Background

Recent studies have compared the performance of cardiac MRI (CMR) with coronary angiography. The CE-MARC trial established CMR's high diagnostic accuracy for coronary artery disease (CAD). Following these results, and those of CE-MARC 2, which showed reduced unnecessary angiography rates with CMR-guided care, we increased our adoption of CMR as an investigation of choice for CAD at our centre.

Purpose

In patients who have a CMR for stable angina, what is the outcome after detection of CAD, how do findings compare with angiography, and do those without CAD identified go on to have a major adverse cardiovascular event (MACE)?

Method

We performed a retrospective audit of all stress CMR performed from August 2016 to March 2017 at our hospital in North England. All patients were followed up for a minimum of 12 months.

NICE guideline care was used during the study period. The CE-MARC trial was used for quality standards and to compare results.

Results

91 stress CMRs were performed. 13 were excluded as they were performed on out-of-area patients. Median follow up was 14.5 months.

Of the remaining 78 patients, 34 (43%) had a positive CMR. 20/34 (59%) proceeded to angiogram. In 16/20 of patients, CMR findings correlated with angiogram findings. A PPV of 80%. The PPV in CE-MARC was 77.2% (72.1–81.6).

Of those who did not proceed to angiography, 8/14 had non-viable myocardium, 3 continued with medical management, in two it was unclear. 3/34 (8.8%) with positive CMR had a MACE.

44 patients had a negative CMR. Three had an angiogram during follow up. All were negative. There was a MACE in 1/44 (2.3%).

Conclusion

The audit population has a similar PPV to that of CE-MARC.

MACE rates at 12 months were similar to CE-MARC which suggests that the trial results are reproducible in our setting. The wider use of CMR can therefore improve investigation and management for patients with stable angina.

The audit is limited by the small number of patients proceeding to angiogram and the ability to confirm negative CMR results.

P782The evaluation of a nurse-led Sacubitril/Valsartan initiation and titration clinic

Background

Sacubitril/Valsartan is a new NICE-approved treatment for heart failure patients with NYHA 2–4 symptoms, LVEF<35% and on a stable dose of ACEi/ARB medication. The PARADIGM-HF trial was stopped early after showing an absolute risk reduction of cardiovascular death/hospitalisation of 5%. NICE specify that it should be initiated by a heart failure specialist with access to a multidisciplinary team. We set up a secondary care specialist nurse-led clinic in our trust in North England for Sacubitril/Valsartan initiation and monitoring.

Purpose

To assess compliance to NICE guidelines and establish the number of clinic visits required for dose titration. To compare demographics and treatment outcomes of our patients with the trial population.

Methods

A retrospective analysis of all patients prescribed Sacubitril/Valsartan over two years with a minimum follow up of 6 months. Data was collected from patient records and compared with NICE guidelines and the PARADIGM-HF trial (total population and Western European subset).

Results

159 patients commenced Sacubitril/Valsartan. Table 1 shows demographic and therapy data and demonstrates our cohort is largely similar to the Western Europe cohort of Paradigm-HF. However, our patients had higher rates of MRA and complex device treatments. Prescribing was compliant with NICE guidelines in 97%. Failure to exceed the target 50% ACEi/ARB dose was the main reason for non-compliance in 60% (3/5). These 3 patients all discontinued. Overall 16% discontinued the drug (42% for hypotension) compared to 18% in the trial. No serious adverse reactions occurred. Mean number of clinic visits was 3.7±1.4.

Table 1. Demographic and therapy data Cohort size Age Female % Ischaemic Aetiology % LVEF B-Blocker % MRA % CRT % ICD % North England 159 69.3±11.1 20 59 27 90 73 23 47 PARADIGM-HF full trial 8442 63.8±11.5 21 60 30 93 54 7 15 Western European Subset 1680 68.3±9.9 18 30 95 44 12 33

Conclusion

Our cohort closely reflects the trial and the resultant NICE guidelines. More of our patients are treated with MRA and complex devices compared to PARADIGM-HF. This may be due to the quality of our service or may reflect our patient selection. Similar tolerability in our patients is reassuring as study patients are highly selected. Those receiving suboptimal ACE/ARB doses (therefore not NICE compliant) prior to initiation all failed to tolerate the new drug which cautions against straying from guidance. Our data shows a specialist nurse-led service can be delivered safely and effectively achieving therapeutic doses with a small number of patient visits. This data supports its deliverability in a non-trial setting.

Are shallow-water shrimps proxies for hydrothermal-vent shrimps to assess the impact of deep-sea mining?

Polymetallic seafloor massive sulphide deposits are potential targets for deep-sea mining, but high concentrations of metals (including copper - Cu) may be released during exploitation activities, potentially inducing harmful impact. To determine whether shallow-water shrimp are suitable ecotoxicological proxies for deep-sea hydrothermal vent shrimp the effects of waterborne Cu exposure (3 and 10 days at 0.4 and 4 μM concentrations) in Palaemon elegans, Palaemon serratus, and Palaemon varians were compared with Mirocaris fortunata. Accumulation of Cu and a set of biomarkers were analysed. Results show different responses among congeneric species indicating that it is not appropriate to use shallow-water shrimps as ecotoxicological proxies for deep-water shrimps. During the evolutionary history of these species they were likely subject to different chemical environments which may have induced different molecular/biochemical adaptations/tolerances. Results highlight the importance of analysing effects of deep-sea mining in situ and in local species to adequately assess ecotoxicological effects under natural environmental conditions.

P4335The incidence of acute rheumatic fever in indigenous adults in the Northern Territory, South Australia and Western Australia

Background

Worldwide, knowledge of the contemporary incidence of acute rheumatic fever (ARF) in Indigenous adult populations is limited, with little understanding of patterns of ARF recurrence according to age and geographical location. This has created uncertainty in the development of rheumatic heart disease (RHD) guidelines surrounding the appropriate duration of antibiotic prophylaxis for these patients.

Purpose

This study aimed to describe the incidence rates of ARF in Indigenous Australian adults, analyse patterns of recurrence according to sex, age and geographical location, and assess adherence to secondary prophylaxis.

Methods

ARF episodes in Indigenous adults, aged 18 years and older, recorded within three Australian jurisdictions (Northern Territory, South Australia and Western Australia) ARF registers, diagnosed between 2007 to 2017, were included. Poisson and negative binomial regression were used to estimate incidence rate ratios (IRR) and 95% confidence intervals (CI) for first and recurrent episodes according to age, sex and remoteness. Adherence rates to secondary prophylaxis was described in the 12 months preceding recurrent ARF episodes in the Northern Territory.

Results

481 episodes were analysed. The incidence of ARF episodes in these jurisdictions from 2007 to 2017 was relatively constant. The overwhelming burden of disease occurred in remote areas (105 episodes per 100,000 people). An increased rate occurred in females (IRR 2.34, 95% CI 1.81–3.03). The 18–24 year olds had the highest incidence rates (115 episodes per 100,000 people). High rates of recurrence were also observed in those aged 25–34 years (96 episodes per 100,000 people). Adherence to secondary prophylaxis in those having a recurrent episode was only achieved in 10% of cases.

Conclusions

The incidence of ARF remains very high amongst adult Indigenous Australians. Adherence to secondary prophylaxis continues to play a role in recurrent episodes. RHD guidelines should take into account remoteness as a significant risk factor when deciding the duration of secondary prophylaxis.

Where Did They Go? Tracking Young Adult Follow-up During the Transition From Pediatric to Adult-Oriented Care

Continuity of care during health care transition is critical. We sought to evaluate electronic medical record clinic attendance data to examine this outcome. We identified 1623 patients (ages 18-27 years) with 1 of 6 childhood-onset chronic conditions and tracked clinic utilization from January 2002 to July 2016. Patients were classified as active in pediatric care; lost from pediatric care; successfully transferred; or lost from adult care. Using random effects logistic regression, we compared the number of days between last pediatric and first adult visit to each clinic's self-reported transitional care quality score. In this cohort, >44% remained active in care at the end of the study. Clinics with higher proportions of successfully transferred patients had lower median numbers of days between last pediatric and first adult visit and higher transitional care quality scores. Characterizing utilization patterns with electronic medical record data allows health systems to track transitional care outcomes and target improvement efforts.

C-43 The Relation Between Executive Functioning and Fluid Reasoning Performance in Children with Attention-Deficit/Hyperactivity Disorder

Objective

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder that affects about 5% of school-aged children.4 Fluid reasoning (FR) tasks assess one’s ability to detect underlying conceptual relationships and use reasoning to identify and apply rules to problem solve.4 Previous research has demonstrated that children with ADHD perform more poorly in FR, though the mechanism behind this is unclear.3,4 The literature suggests that FR is reliant on executive functioning skills such as inhibitory control, working memory, and planning.1,4 Therefore, this study examines how performance on FR from the Wechsler Intelligence Scale for Children (WISC-V) is related to measures of executive functioning (EF) and attention in children with ADHD.

Method

Participants were children aged 8 to 16-years with ADHD (N = 75) referred for neuropsychological testing. Participant demographics: males (N = 50, 65.8%), females (N = 26, 34.2%); African American (5.3%), Asian (1.3%), Caucasian (52.6%), Other (39.5%). Measures included the WISC-V Fluid Reasoning Index (FRI), Delis-Kaplan Executive Function System (DKEFS) Color Word Identification (CWI) and Tower subtests, omissions/commissions on the Conners Continuous Performance Test (CPT), and Behavior Rating Inventory of Executive Functioning (BRIEF) subscales.

Results

Bivariate correlations showed that the FRI was only significantly positively correlated with CWI Inhibition/Switching Time (r = .246, p = .047). Commission errors on the CPT approached significance (r = .217, p = .145).

Conclusion

The WISC-V FRI may be vulnerable to weaknesses in EF or behavioral control in children with ADHD and should be interpreted in that context. Findings suggest the FRI may be particularly impacted by weaknesses in inhibitory control.