Attosecond and nano-Coulomb electron bunches via the Zero Vector Potential mechanism

The commissioning of multi-petawatt class laser facilities around the world is gathering pace. One of the primary motivations for these investments is the acceleration of high-quality, low-emittance electron bunches. Here we explore the interaction of a high-intensity femtosecond laser pulse with a mass-limited dense target to produce MeV attosecond electron bunches in transmission and confirm with three-dimensional simulation that such bunches have low emittance and nano-Coulomb charge. We then perform a large parameter scan from non-relativistic laser intensities to the laser-QED regime and from the critical plasma density to beyond solid density to demonstrate that the electron bunch energies and the laser pulse energy absorption into the plasma can be quantitatively described via the Zero Vector Potential mechanism. These results have wide-ranging implications for future particle accelerator science and associated technologies.

Effectiveness of out-patient based acute heart failure care: a pilot randomised controlled trial

OBJECTIVES

Acute heart failure (AHF) hospitalisation is associated with 10% mortality. Outpatient based management (OPM) of AHF appeared effective in observational studies. We conducted a pilot randomised controlled trial (RCT) comparing OPM with standard inpatient care (IPM).

METHODS

We randomised patients with AHF, considered to need IV diuretic treatment for ≥2 days, to IPM or OPM. We recorded all-cause mortality, and the number of days alive and out-of-hospital (DAOH). Quality of life, mental well-being and Hope scores were assessed. Mean NHS cost savings and 95% central range (CR) were calculated from bootstrap analysis. Follow-up: 60 days.

RESULTS

Eleven patients were randomised to IPM and 13 to OPM. There was no statistically significant difference in all-cause mortality during the index episode (1/11 vs 0/13) and up to 60 days follow-up (2/11 vs 2/13) [p = .86]. The OPM group accrued more DAOH {47 [36,51] vs 59 [41,60], p = .13}. Two patients randomised to IPM (vs 6 OPM) were readmitted [p = .31]. Hope scores increased more with OPM within 30 days but dropped to lower levels than IPM by 60 days. More out-patients had increased total well-being scores by 60 days (p = .04). OPM was associated with mean cost savings of £2658 (95% CR 460-4857) per patient.

CONCLUSIONS

Patients with acute HF randomised to OPM accrued more days alive out of hospital (albeit not statistically significantly in this small pilot study). OPM is favoured by patients and carers and is associated with improved mental well-being and cost savings.

Measuring spatio-temporal couplings using modal spatio-spectral wavefront retrieval

Knowledge of spatio-temporal couplings such as pulse-front tilt or curvature is important to determine the focused intensity of high-power lasers. Common techniques to diagnose these couplings are either qualitative or require hundreds of measurements. Here we present both a new algorithm for retrieving spatio-temporal couplings, as well as novel experimental implementations. Our method is based on the expression of the spatio-spectral phase in terms of a Zernike-Taylor basis, allowing us to directly quantify the coefficients for common spatio-temporal couplings. We take advantage of this method to perform quantitative measurements using a simple experimental setup, consisting of different bandpass filters in front of a Shack-Hartmann wavefront sensor. This fast acquisition of laser couplings using narrowband filters, abbreviated FALCON, is easy and cheap to implement in existing facilities. To this end, we present a measurement of spatio-temporal couplings at the ATLAS-3000 petawatt laser using our technique.

Neutron emission spectrometer to measure ion temperature on the Fusion Demonstration Plant

General Fusion is building the Fusion Demonstration Plant to demonstrate a magnetized target fusion scheme in which a deuterium plasma is heated from 200 eV to 10 keV by piston-driven compression of a liquid-lithium liner. The multilayer coaxial time-of-flight neutron emission spectrometer is designed to measure the ion temperature near peak compression at which time the neutron yield will approach 10¹⁸ neutrons/s. The neutron energy distribution is expected to be Gaussian since the machine uses no neutral beam or radio-frequency heating. In this case, analysis shows that as few as 500 coincidence events should be sufficient to accurately measure the ion temperature. This enables a fast time resolution of 10 µs, which is required to track the rapid change in temperature approaching peak compression. We overcome the challenges of neutron pile-up and event ambiguity with a compact design having two layers of segmented scintillators. The error in the ion temperature measurement is computed as a function of the neutron spectrometer's geometric parameters and used to optimize the design for the case of reaching 10 keV at peak compression.

Supporting individuals with intellectual and developmental disability during the first 100 days of the COVID-19 outbreak in the USA

BACKGROUND

It is unknown how the novel Coronavirus SARS-CoV-2, the cause of the current acute respiratory illness COVID-19 pandemic that has infected millions of people, affects people with intellectual and developmental disability (IDD). The aim of this study is to describe how individuals with IDD have been affected in the first 100 days of the COVID-19 pandemic.

METHODS

Shortly after the first COVID-19 case was reported in the USA, our organisation, which provides continuous support for over 11 000 individuals with IDD, assembled an outbreak committee composed of senior leaders from across the health care organisation. The committee led the development and deployment of a comprehensive COVID-19 prevention and suppression strategy, utilising current evidence-based practice, while surveilling the global and local situation daily. We implemented enhanced infection control procedures across 2400 homes, which were communicated to our employees using multi-faceted channels including an electronic resource library, mobile and web applications, paper postings in locations, live webinars and direct mail. Using custom-built software applications enabling us to track patient, client and employee cases and exposures, we leveraged current public health recommendations to identify cases and to suppress transmission, which included the use of personal protective equipment. A COVID-19 case was defined as a positive nucleic acid test for SARS-CoV-2 RNA.

RESULTS

In the 100-day period between 20 January 2020 and 30 April 2020, we provided continuous support for 11 540 individuals with IDD. Sixty-four per cent of the individuals were in residential, community settings, and 36% were in intermediate care facilities. The average age of the cohort was 46 ± 12 years, and 60% were male. One hundred twenty-two individuals with IDD were placed in quarantine for exhibiting symptoms and signs of acute infection such as fever or cough. Sixty-six individuals tested positive for SARS-CoV-2, and their average age was 50. The positive individuals were located in 30 different homes (1.3% of total) across 14 states. Fifteen homes have had single cases, and 15 have had more than one case. Fifteen COVID-19-positive individuals were hospitalised. As of 30 April, seven of the individuals hospitalised have been discharged back to home and are recovering. Five remain hospitalised, with three improving and two remaining in intensive care and on mechanical ventilation. There have been three deaths. We found that among COVID-19-positive individuals with IDD, a higher number of chronic medical conditions and male sex were characteristics associated with a greater likelihood of hospitalisation.

CONCLUSIONS

In the first 100 days of the COVID-19 outbreak in the USA, we observed that people with IDD living in congregate care settings can benefit from a coordinated approach to infection control, case identification and cohorting, as evidenced by the low relative case rate reported. Male individuals with higher numbers of chronic medical conditions were more likely to be hospitalised, while most younger, less chronically ill individuals recovered spontaneously at home.

The psychological impact of Stevens-Johnson syndrome and toxic epidermal necrolysis on patients' lives: a Critically Appraised Topic

CLINICAL SCENARIO

A 65-year-old man presented with a 12-h history of deteriorating rash. Two weeks previously he had completed a course of neoadjuvant chemotherapy for ductal carcinoma of the breast. On examination there were bullae, widespread atypical targetoid lesions and 15% epidermal detachment. There was no mucosal involvement on presentation, but subsequently it did evolve. Skin biopsy showed subepidermal blistering with epidermal necrosis. This confirmed our clinical diagnosis of overlap Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN). On transfer to intensive care he was anxious and fearful.

MANAGEMENT QUESTION

What are the psychological impacts of SJS/TEN on this man's life?

BACKGROUND

SJS and TEN have devastating outcomes for those affected.

OBJECTIVES

To conduct a Critically Appraised Topic to (i) analyse existing research related to the psychological impact of SJS and TEN and (ii) apply the results to the clinical scenario.

METHODS

Seven electronic databases were searched for publications focusing on the psychological impact of SJS/TEN on adults over 18 years of age.

RESULTS

Six studies met the inclusion criteria. Healthcare practitioners' (HCPs') lack of information around the disorder was highlighted. Patients experienced undue stress and fear. Some patients had symptoms aligned to post-traumatic stress disorder (PTSD), anxiety and depression.

DISCUSSION AND RECOMMENDATION

The evidence suggests that SJS and TEN impact psychologically on patients' lives. Education of HCPs, to address their lack of awareness and information on SJS/TEN, should facilitate their capacity to provide information and support to patients, thereby reducing patient anxiety. On discharge, a follow-up appointment with relevant HCPs to reduce the possibility of PTSD occurring should be considered.

Frailty and hospital outcomes within a low socioeconomic population

BACKGROUND

Clinical frailty scales (CFS) predict hospital-related outcomes. Frailty is more common in areas of higher socioeconomic disadvantage, but no studies exclusively report on the impact of CFS on hospital-related outcomes in areas of known socioeconomic disadvantage.

AIMS

To evaluate the association of the CFS with hospital-related outcomes.

DESIGN

Retrospective observational study in a community hospital within a disadvantaged area in Australia (Social Economic Index for Areas = 0.1%).

METHODS

The CFS was used in the emergency department (ED) for people aged ≥ 75 years. Frailty was defined as a score of ≥4. Associations between the CFS and mortality, admission rates, ED presentations and length of stay (LOS) were analysed using regression analyses.

RESULTS

Between 11 July 2017 and 31 March 2018, there were 5151 ED presentations involving 3258 patients aged ≥ 75 years. Frail persons were significantly more likely to be older, represent to the ED and have delirium compared with non-frail persons. CFS was independently associated with 28-day mortality, with odds of mortality increasing by 1.5 times per unit increase in CFS (95% CI: 1.3-1.7). Frail persons with CFS 4-6 were more likely to be admitted (OR: 1.2; 95% CI: 1.0-1.5), have higher geometric mean LOS (1.43; 95% CI 1.15-1.77 days) and higher rates of ED presentations (IRR: 1.12; 95% CI 1.04-1.21) compared with non-frail persons.

CONCLUSIONS

The CFS predicts community hospital-related outcomes in frail persons within a socioeconomic disadvantage area. Future intervention and allocation of resources could consider focusing on CFS 4-6 as a priority for frail persons within a community hospital setting.

Abstract P2-11-19: Safety and efficacy of re-irradiation for locoregional breast cancer recurrences using pulsed reduced dose rate technique and concurrent capecitabine

Purpose: Locoregionally recurrent breast cancer presents a tremendous therapeutic challenge, but successful treatment can provide a durable cure. Re-irradiation has been performed infrequently in the recurrent setting due to concern for toxicity. Pulsed reduced dose rate radiation is a technique that can decrease the toxicity of re-irradiation by increasing normal tissue repair. Here, we update our previously published results of chest wall re-irradiation with an additional 16 patients and a focus on outcomes and long term toxicities.

Methods: Patients treated from 11/09/2000 to 04/21/2016 with pulsed reduced dose rate radiation therapy at the University of Wisconsin were identified by query of Aria radiation oncology record software. Patients were retreated to a median dose of 54 Gy (range 37.5-66 Gy) using pulsed reduced does rate technique, delivering radiation at an apparent dose rate of 0.067 Gy/min to allow for normal tissue repair. The median cumulative dose was 109.8 Gy (range 75 to 236 Gy). Eleven patients underwent comprehensive re-irradiation to the chest wall and locoregional lymphatics, while the remainder underwent re-treatment limited to the site of recurrence. Concurrent capecitabine was given to 15 patients, most frequently at 500mg BID (range 1000 mg to 1500mg daily). The Kaplan-Meier method was used for survival analysis.

Results: Thirty-three patients were identified who were treated with pulsed reduced dose rate radiation therapy for locoregionally recurrent invasive breast cancer with a median follow-up of 19.8 months (range 6.8-133.8 months). Sixteen patients were treated with curative intent and 17 patients were treated with palliative intent. Twenty-two patients had gross disease present at the time of treatment, 6 patients had microscopically positive surgical margins, and 5 patients were treated who had negative margins. The 2 year locoregional recurrence free survival was 70.5% by the Kaplan-Meier method for all patients and 81.5% for patients treated with curative intent. Two year overall survival was 43.6% for all patients and 72.2% in patients treated with curative intent. The rate of acute grade 3 skin toxicity was 21.2%. No other acute grade three toxicities occurred. A total of 9 patients (27.2%) developed late grade 3 or greater toxicities, including 4 patients who developed lymphedema, 4 patients who developed non-healing wounds, and one patient who developed both lymphedema and a non-healing wound.

Conclusion: Pulsed reduced dose rate radiation therapy with capecitabine is an effective method for treating patients with recurrent breast cancer. The moderate risk of toxicity is warranted in a subset of patients with high risk of disease recurrence or morbidity from disease progression. Further work, including prospective studies, is needed to determine the patients who who will benefit most from this technique.

Citation Format: Burr A, Howard S. Safety and efficacy of re-irradiation for locoregional breast cancer recurrences using pulsed reduced dose rate technique and concurrent capecitabine [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-19.

Response of Pacific-sector Antarctic ice shelves to the El Niño/Southern Oscillation

Satellite observations over the past two decades have revealed increasing loss of grounded ice in West Antarctica, associated with floating ice shelves that have been thinning. Thinning reduces an ice-shelf's ability to restrain grounded-ice discharge, yet our understanding of the climate processes that drive mass changes is limited. Here, we use ice-shelf height data from four satellite altimeter missions (1994-2017) to show a direct link between ice-shelf-height variability in the Antarctic Pacific sector and changes in regional atmospheric circulation driven by the El Niño-Southern Oscillation. This link is strongest from Dotson to Ross ice shelves and weaker elsewhere. During intense El Niño years, height increase by accumulation exceeds the height decrease by basal melting, but net ice-shelf mass declines as basal ice loss exceeds lower-density snow gain. Our results demonstrate a substantial response of Amundsen Sea ice shelves to global and regional climate variability, with rates of change in height and mass on interannual timescales that can be comparable to the longer-term trend, and with mass changes from surface accumulation offsetting a significant fraction of the changes in basal melting. This implies that ice-shelf height and mass variability will increase as interannual atmospheric variability increases in a warming climate.

New Limits on Bosonic Dark Matter, Solar Axions, Pauli Exclusion Principle Violation, and Electron Decay from the Majorana Demonstrator

We present new limits on exotic keV-scale physics based on 478 kg d of Majorana Demonstrator commissioning data. Constraints at the 90% confidence level are derived on bosonic dark matter (DM) and solar axion couplings, Pauli exclusion principle violating (PEPV) decay, and electron decay using monoenergetic peak signal limits above our background. Our most stringent DM constraints are set for 11.8 keV mass particles, limiting g_{Ae}<4.5×10^{-13} for pseudoscalars and (α^{'}/α)<9.7×10^{-28} for vectors. We also report a 14.4 keV solar axion coupling limit of g_{AN}^{eff}×g_{Ae}<3.8×10^{-17}, a 1/2β^{2}<8.5×10^{-48} limit on the strength of PEPV electron transitions, and a lower limit on the electron lifetime of τ_{e}>1.2×10^{24}  yr for e^{-}→ invisible.

A refined risk stratification scheme for clinical stage 1 NSGCT based on evaluation of both embryonal predominance and lymphovascular invasion

BACKGROUND

Active surveillance is an increasingly accepted approach for managing patients with germ-cell tumors (GCTs) after an orchiectomy. Here we investigate a time-to-relapse stratification scheme for clinical stage 1 (CS1) nonseminoma GCT (NSGCT) patients according to factors associated with relapse and identify a group of patients with a lower frequency and longer time-to-relapse who may require an alternative surveillance strategy.

PATIENTS AND METHODS

We analyzed 266 CS1 GCT patients from the IRB-approved DFCI GCT database that exclusively underwent surveillance following orchiectomy from 1997 to 2013. We stratified NSGCT patients according to predominance of embryonal carcinoma (EmbP) and lymphovascular invasion (LVI), using a 0, 1, and 2 scoring system. Cox regression and conditional risk analysis were used to compare each NSGCT group to patients in the seminomatous germ-cell tumor (SGCT) category. Median time-to-relapse values were then calculated among those patients who underwent relapse. Relapse-free survival curves were generated using the Kaplan-Meier method.

RESULTS

Fifty (37%) NSGCT and 20 (15%) SGCT patients relapsed. The median time-to-relapse was 11.5 versus 6.3 months for the SGCT and NSGCT groups, respectively. For NSGCT patients, relapse rates were higher and median time-to-relapse faster with increasing number of risk factors (RFs). Relapse rates (%) and median time-to-relapse (months) were 25%/8.5 months, 41%/6.8 months and 78%/3.8 months for RF0, RF1 and RF2, respectively. We found a statistically significant difference between SGCT and patients with one or two RFs (P < 0.001) but not between SGCT and NSGCT RF0 (P = 0.108).

CONCLUSION

NSGCT patients grouped by a risk score system based on EmbP and LVI yielded three groups with distinct relapse patterns -and patients with neither EmbP nor LVI appear to behave similar to SGCT.

Effects of a school-based sexuality education program on peer educators: the Teen PEP model

This study evaluated the impact of the Teen Prevention Education Program (Teen PEP), a peer-led sexuality education program designed to prevent unintended pregnancy and sexually transmitted infections (STIs) including HIV among high school students. The study design was a quasi-experimental, nonrandomized design conducted from May 2007 to May 2008. The sample consisted of 96 intervention (i.e. Teen PEP peer educators) and 61 comparison students from five high schools in New Jersey. Baseline and 12-month follow-up surveys were conducted. Summary statistics were generated and multiple regression analyses were conducted. In the primary intent-to-treat analyses, and secondary non-intent-to-treat analyses, Teen PEP peer educators (versus comparison students) reported significantly greater opportunities to practice sexual risk reduction skills and higher intentions to talk with friends, parents, and sex partners about sex and birth control, set boundaries with sex partners, and ask a partner to be tested for STIs including HIV. In addition in the secondary analysis, Teen PEP peer educators (as compared with the comparison students) had significantly higher scores on knowledge of sexual health issues and ability to refuse risky sexual situations. School-based sexuality education programs offering comprehensive training to peer educators may improve sexual risk behavior knowledge, attitudes and behaviors among high school students.