Measuring the principal Hugoniot of inertial-confinement-fusion-relevant TMPTA plastic foams.

Wetted-foam layers are of significant interest for inertial-confinement-fusion capsules, due to the control they provide over the convergence ratio of the implosion and the opportunity this affords to minimize hydrodynamic instability growth. However, the equation of state for fusion-relevant foams are not well characterized, and many simulations rely on modeling such foams as a homogeneous medium with the foam average density. To address this issue, an experiment was performed using the VULCAN Nd:glass laser at the Central Laser Facility. The aim was to measure the principal Hugoniot of TMPTA plastic foams at 260mg/cm^{3}, corresponding to the density of liquid DT-wetted-foam layers, and their "hydrodynamic equivalent" capsules. A VISAR was used to obtain the shock velocity of both the foam and an α-quartz reference layer, while streaked optical pyrometry provided the temperature of the shocked material. The measurements confirm that, for the 20-120 GPa pressure range accessed, this material can indeed be well described using the equation of state of the homogeneous medium at the foam density.

Usage of C-Reactive Protein Testing in the Diagnosis and Monitoring of Psoriatic Arthritis (PsA): Results from a Real-World Survey in the USA and Europe.

INTRODUCTION: C-reactive protein (CRP) is an important non-specific marker of both acute and chronic inflammation and can be elevated in patients with psoriatic arthritis (PsA). However, the use of CRP testing in the management of PsA can vary. This study investigated how CRP testing is implemented in real-world clinical practice for disease management of PsA. METHODS: A point-in-time survey of rheumatologists and dermatologists and their next six consulting patients with PsA was conducted in France, Germany, Italy, Spain, UK (EU5), and the USA between June and August 2018. Use of CRP testing was obtained by asking the physician to state (yes/no) whether CRP was used to aid PsA diagnosis and/or to monitor the patient's disease activity. The number of CRP tests conducted in the last 12 months for each patient enrolled was provided. RESULTS: Data were collected for 2270 patients (USA, n = 595; EU5, n = 1675). In the EU5, CRP testing was conducted to aid diagnosis in 78.7% of patients (vs. 43.4% in USA) and CRP was used to monitor disease activity in 72.0% (vs. 34.6% in USA). The majority (80.9%) of patients in the EU5 had at least one CRP test in the last 12 months compared to 42.9% in the USA. Patients treated by rheumatologists (vs. dermatologists) were at least 50% more likely to have CRP tested for monitoring purposes, this difference being most pronounced in the USA. In the EU5, CRP testing was conducted a mean ± standard deviation of 2.7 ± 1.7 times during the last 12 months, versus 2.0 ± 1.4 in the USA. CONCLUSIONS: CRP was more commonly used for the diagnosis and monitoring of PsA in Europe compared to the USA and was more commonly ordered by rheumatologists than dermatologists. In the absence of a better serum biomarker of inflammation, more data are needed to understand how CRP testing should be used in the diagnosis and management PsA.

Real-world effectiveness and rheumatologist satisfaction with secukinumab in the treatment of patients with axial spondyloarthritis.

OBJECTIVES: To assess the effectiveness of secukinumab in patients with axSpA treated in routine clinical settings in 5 European countries. METHODS: Retrospective analysis of a cross-sectional survey to assess real-world effectiveness of secukinumab in the management of axSpA and rheumatologist satisfaction with treatment in France, Germany, Italy, Spain and the UK from March to December 2018. Outcomes collected included patient demographics, clinical characteristics and rheumatologist- and patient-reported satisfaction with secukinumab treatment. RESULTS: Five hundred thirty-five patients receiving secukinumab for more than 4 months were assessed, 359 of whom were diagnosed with AS and 178 with nr-axSpA. Rheumatologist assessment of disease status at treatment initiation indicated that 39 (7.3%) had stable/improving disease. Secukinumab treatment for 4 months or longer resulted in 515 (95.9%) patients judged as stable/improving. Treatment was associated with benefits from initiation to assessment in terms of BASDAI (6.2 vs 2.8), 44-joint count score (9.7 vs 6.6), rheumatologist global VAS score (56.9 vs 23.0) and patient global VAS scores (64.4 vs 25.5). These benefits for key clinical outcomes were sustained for periods of 12 months or longer. Patient-reported outcomes on health status using EQ-5D, global functioning using the ASAS health index and overall work impairment via WPAI were sustained over the treatment period, while patient and rheumatologist satisfaction with secukinumab treatment remained very high at 80.2 and 91.2%, respectively. CONCLUSION: Consistent benefits across multiple clinical and patient-reported outcomes were seen with secukinumab treatment in patients with AS and nr-axSpA treated in routine clinical settings across five European countries. Key Points • In routine clinical settings across five European countries, secukinumab treatment resulted in improvements in a wide range of clinical outcomes including physician-reported disease severity, disease status, pain, BASDAI, 44-joint count score and global VAS scores. • Key clinical and patient reported outcomes were sustained for a 12-month period or longer with secukinumab treatment. • Rheumatologist- and patient-reported treatment satisfaction was high with secukinumab.

Selective Ion Acceleration by Intense Radiation Pressure.

We report on the selective acceleration of carbon ions during the interaction of ultrashort, circularly polarized and contrast-enhanced laser pulses, at a peak intensity of 5.5×10^{20} W/cm^{2}, with ultrathin carbon foils. Under optimized conditions, energies per nucleon of the bulk carbon ions reached significantly higher values than the energies of contaminant protons (33 MeV/nucleon vs 18 MeV), unlike what is typically observed in laser-foil acceleration experiments. Experimental data, and supporting simulations, emphasize different dominant acceleration mechanisms for the two ion species and highlight an (intensity dependent) optimum thickness for radiation pressure acceleration; it is suggested that the preceding laser energy reaching the target before the main pulse arrives plays a key role in a preferential acceleration of the heavier ion species.

Estimates of Caffeine Use Disorder, Caffeine Withdrawal, Harm and Help-seeking in New Zealand: A cross-sectional survey.

BACKGROUND: Caffeine Use Disorder (CUD) is not yet formally recognized in the DSM-5, but emerging evidence suggests CUD could impact up to one in five people. The primary aim of this study was to estimate levels of caffeine consumption and its associations with CUD and withdrawal, taking socio-demographic characteristics (age, gender, ethnicity, income) into account. Secondary aims were to measure caffeine-related harm and treatment preferences. METHODS: We administered an online cross-sectional survey via Facebook to a convenience sample of 2379 adults in New Zealand. Caffeine consumption was assessed across six products: coffee, tea, energy drinks, cola, alcohol mixed with caffeine, and other products (e.g., caffeine pills, sports supplements). RESULTS: 20% of participants met proposed criteria for CUD, with 30% meeting DSM-5 criteria for caffeine withdrawal. Moderate (200-400 mg per day) and high consumption (>400 mg per day) was associated with a three-fold increase in the odds of CUD and a two-fold increase in the odds of withdrawal. Women and current smokers were at higher risk of CUD and withdrawal even at moderate consumption levels. Nearly 85% of respondents experienced at least one caffeine-related harm in the past 12-months. The number of harms increased with level of caffeine consumption. Nearly 50% indicated a self-help treatment for caffeine reduction would be of interest. CONCLUSIONS: High rates of CUD and caffeine withdrawal amongst moderate caffeine users, women and smokers suggests caffeine consumption guidelines may need refinement. Caffeine-related harm that is not clinically meaningful may still be of concern to individuals and warrants further investigation.

Effect of plastic coating on the density of plasma formed in Si foil targets irradiated by ultra-high-contrast relativistic laser pulses.

The formation of high energy density matter occurs in inertial confinement fusion, astrophysical, and geophysical systems. In this context, it is important to couple as much energy as possible into a target while maintaining high density. A recent experimental campaign, using buried layer (or "sandwich" type) targets and the ultrahigh laser contrast Vulcan petawatt laser facility, resulted in 500 Mbar pressures in solid density plasmas (which corresponds to about 4.6×10^{7}J/cm^{3} energy density). The densities and temperatures of the generated plasma were measured based on the analysis of x-ray spectral line profiles and relative intensities.

Seeing is believing: The effect of prison-based insight-days on student nurses' perceptions of undertaking practice placements within a prison healthcare environment.

Prisoners' access to healthcare should mirror that of the general public, but is adversely affected by challenges in recruiting nurses to work in custodial settings, potentially impacting on prisoner well-being. To address this issue prison-based insight-days have been developed jointly by one university and prison to positively influence students' views of undertaking placements in custodial settings because nurses are known to subsequently seek employment in areas where they have had positive student placements. A phenomenological investigation explored student nurses' lived experiences of prison-based insight-days. Questionnaires and interviews were used to gather qualitative data about students' feelings both prior to and following the insight-day (n = 17). All data was thematically analysed resulting in four themes: pre-placement curiosity, escalating admission anxiety, calming down inside and post-placement decision making. The empirical findings showed that first-hand exposure to prisoners, and to the realities of a working prison, were crucial factors in dispelling stereotypes and addressing negative preconceptions of prison healthcare environments, as students could find prison placements unexpectedly appealing. Drawing on the findings, this paper recommends that facilitating prison insight-days within custodial settings may be one way to encourage students to undertake prison placements.

A classification-based approach to low back pain in primary care - protocol for a benchmarking controlled trial.

BACKGROUND: Guidelines recommend a biopsychosocial framework for low back pain (LBP) management and the avoidance of inappropriate imaging. In clinical practice, care strategies are often inconsistent with evidence and guidelines, even though LBP is the most common disabling health condition worldwide. Unhelpful beliefs, attitudes and inappropriate imaging are common. LBP is understood to be a complex biopsychosocial phenomenon with many known multidimensional risk factors (symptom- and lifestyle-related, psychological and social) for persistent or prolonged disability, which should be identified and addressed by treatment. The STarT Back Tool (SBT) was developed for early identification of individual risk factors of LBP to enable targeted care. Stratified care according SBT has been shown to improve the effectiveness of care in a primary care setting. A biopsychosocially-oriented patient education booklet, which includes imaging guidelines and information, is one possible way to increase patients' understanding of LBP and to reduce inappropriate imaging. Premeditated pathways, education of professionals, written material, and electronic patient registry support in health care organizations could help implement evidence-based care. METHODS: We will use a Benchmarking Controlled Trial (BCT) design in our study. We will prospectively collect data from three health care regions before and after the implementation of a classification-based approach to LBP in primary care. The primary outcome will be change in PROMIS (Patient-Reported Outcomes Measurement Information System) (short form 20a) over 12-month follow-up. DISCUSSION: The implementation of a classification-based biopsychosocial approach can potentially improve the care of LBP patients, reduce inappropriate imaging without increasing health-care costs, and decrease indirect costs by reducing work disability. Using the BCT we will be able to evaluate the effectiveness of the improvement strategy for the entire care pathway. TRIAL REGISTRATION: ISRCTN,ISRCTN13273552, retrospectively registered 13/05/2019.

High order mode structure of intense light fields generated via a laser-driven relativistic plasma aperture.

The spatio-temporal and polarisation properties of intense light is important in wide-ranging topics at the forefront of extreme light-matter interactions, including ultrafast laser-driven particle acceleration, attosecond pulse generation, plasma photonics, high-field physics and laboratory astrophysics. Here, we experimentally demonstrate modifications to the polarisation and temporal properties of intense light measured at the rear of an ultrathin target foil irradiated by a relativistically intense laser pulse. The changes are shown to result from a superposition of coherent radiation, generated by a directly accelerated bipolar electron distribution, and the light transmitted due to the onset of relativistic self-induced transparency. Simulations show that the generated light has a high-order transverse electromagnetic mode structure in both the first and second laser harmonics that can evolve on intra-pulse time-scales. The mode structure and polarisation state vary with the interaction parameters, opening up the possibility of developing this approach to achieve dynamic control of structured light fields at ultrahigh intensities.

A new energy spectrum reconstruction method for time-of-flight diagnostics of high-energy laser-driven protons.

The Time-of-Flight (TOF) technique coupled with semiconductorlike detectors, as silicon carbide and diamond, is one of the most promising diagnostic methods for high-energy, high repetition rate, laser-accelerated ions allowing a full on-line beam spectral characterization. A new analysis method for reconstructing the energy spectrum of high-energy laser-driven ion beams from TOF signals is hereby presented and discussed. The proposed method takes into account the detector's working principle, through the accurate calculation of the energy loss in the detector active layer, using Monte Carlo simulations. The analysis method was validated against well-established diagnostics, such as the Thomson parabola spectrometer, during an experimental campaign carried out at the Rutherford Appleton Laboratory (UK) with the high-energy laser-driven protons accelerated by the VULCAN Petawatt laser.

Neutron diffraction of deuterated tripalmitin and the influence of shear on its crystallisation.

This neutron diffraction study of deuterated tripalmitin has provided further insight into a forensic observation of the crystallisation of lipids under high-shear conditions. To achieve this, an experimental set up was designed to enable simultaneous rheological data from a Couette cell to be recorded with neutron powder diffraction, enabling the influence of shear on the polymorph transformation on cooling to be monitored in real time. Tripalmitin was observed to directly transform from a liquid phase to a ß polymorph under the influence of shear. Although the liquid to ß transition was not observed to be influenced by shear rate, the degree of crystallinity, qualitatively denoted by an increase in the sharpness of the diffraction peaks, was observed at higher shear rates. Evidence is also presented that the rate of cooling influences the ordering in the ß-polymorph produced in zero shear conditions.

Ultrafast Imaging of Laser Driven Shock Waves using Betatron X-rays from a Laser Wakefield Accelerator.

Betatron radiation from laser wakefield accelerators is an ultrashort pulsed source of hard, synchrotron-like x-ray radiation. It emanates from a centimetre scale plasma accelerator producing GeV level electron beams. In recent years betatron radiation has been developed as a unique source capable of producing high resolution x-ray images in compact geometries. However, until now, the short pulse nature of this radiation has not been exploited. This report details the first experiment to utilize betatron radiation to image a rapidly evolving phenomenon by using it to radiograph a laser driven shock wave in a silicon target. The spatial resolution of the image is comparable to what has been achieved in similar experiments at conventional synchrotron light sources. The intrinsic temporal resolution of betatron radiation is below 100 fs, indicating that significantly faster processes could be probed in future without compromising spatial resolution. Quantitative measurements of the shock velocity and material density were made from the radiographs recorded during shock compression and were consistent with the established shock response of silicon, as determined with traditional velocimetry approaches. This suggests that future compact betatron imaging beamlines could be useful in the imaging and diagnosis of high-energy-density physics experiments.

Time-resolved measurements of fast electron recirculation for relativistically intense femtosecond scale laser-plasma interactions.

A key issue in realising the development of a number of applications of high-intensity lasers is the dynamics of the fast electrons produced and how to diagnose them. We report on measurements of fast electron transport in aluminium targets in the ultra-intense, short-pulse (<50 fs) regime using a high resolution temporally and spatially resolved optical probe. The measurements show a rapidly (≈0.5c) expanding region of Ohmic heating at the rear of the target, driven by lateral transport of the fast electron population inside the target. Simulations demonstrate that a broad angular distribution of fast electrons on the order of 60° is required, in conjunction with extensive recirculation of the electron population, in order to drive such lateral transport. These results provide fundamental new insight into fast electron dynamics driven by ultra-short laser pulses, which is an important regime for the development of laser-based radiation and particle sources.

Micron-scale mapping of megagauss magnetic fields using optical polarimetry to probe hot electron transport in petawatt-class laser-solid interactions.

The transport of hot, relativistic electrons produced by the interaction of an intense petawatt laser pulse with a solid has garnered interest due to its potential application in the development of innovative x-ray sources and ion-acceleration schemes. We report on spatially and temporally resolved measurements of megagauss magnetic fields at the rear of a 50-µm thick plastic target, irradiated by a multi-picosecond petawatt laser pulse at an incident intensity of ~1020 W/cm2. The pump-probe polarimetric measurements with micron-scale spatial resolution reveal the dynamics of the magnetic fields generated by the hot electron distribution at the target rear. An annular magnetic field profile was observed ~5 ps after the interaction, indicating a relatively smooth hot electron distribution at the rear-side of the plastic target. This is contrary to previous time-integrated measurements, which infer that such targets will produce highly structured hot electron transport. We measured large-scale filamentation of the hot electron distribution at the target rear only at later time-scales of ~10 ps, resulting in a commensurate large-scale filamentation of the magnetic field profile. Three-dimensional hybrid simulations corroborate our experimental observations and demonstrate a beam-like hot electron transport at initial time-scales that may be attributed to the local resistivity profile at the target rear.

Using X-ray spectroscopy of relativistic laser plasma interaction to reveal parametric decay instabilities: a modeling tool for astrophysics.

By analyzing profiles of experimental x-ray spectral lines of Si XIV and Al XIII, we found that both Langmuir and ion acoustic waves developed in plasmas produced via irradiation of thin Si foils by relativistic laser pulses (intensities ~1021 W/cm2). We prove that these waves are due to the parametric decay instability (PDI). This is the first time that the PDI-induced ion acoustic turbulence was discovered by the x-ray spectroscopy in laser-produced plasmas. These conclusions are also supported by PIC simulations. Our results can be used for laboratory modeling of physical processes in astrophysical objects and a better understanding of intense laser-plasma interactions.

Plasma scale-length effects on electron energy spectra in high-irradiance laser plasmas.

An analysis of an electron spectrometer used to characterize fast electrons generated by ultraintense (10^{20}Wcm^{-2}) laser interaction with a preformed plasma of scale length measured by shadowgraphy is presented. The effects of fringing magnetic fields on the electron spectral measurements and the accuracy of density scale-length measurements are evaluated. 2D EPOCH PIC code simulations are found to be in agreement with measurements of the electron energy spectra showing that laser filamentation in plasma preformed by a prepulse is important with longer plasma scale lengths (>8 µm).

Laboratory measurements of resistivity in warm dense plasmas relevant to the microphysics of brown dwarfs.

Since the observation of the first brown dwarf in 1995, numerous studies have led to a better understanding of the structures of these objects. Here we present a method for studying material resistivity in warm dense plasmas in the laboratory, which we relate to the microphysics of brown dwarfs through viscosity and electron collisions. Here we use X-ray polarimetry to determine the resistivity of a sulphur-doped plastic target heated to Brown Dwarf conditions by an ultra-intense laser. The resistivity is determined by matching the plasma physics model to the atomic physics calculations of the measured large, positive, polarization. The inferred resistivity is larger than predicted using standard resistivity models, suggesting that these commonly used models will not adequately describe the resistivity of warm dense plasma related to the viscosity of brown dwarfs.

Analysis of Short-Term Cortisol Stress Response in Channel Catfish by Anesthetization with Metomidate Hydrochloride and Tricaine Methanesulfonate.

The ability of the anesthetics metomidate hydrochloride and tricaine methanesulfonate (MS-222) to mitigate the cortisol stress response of Channel Catfish Ictalurus punctatus was evaluated during a 10-min confinement stress. The cortisol concentrations of Channel Catfish anesthetized in metomidate hydrochloride remained consistent throughout the 10-min exposure; however, for fish anesthetized with MS-222 and nonanesthetized fish, cortisol concentrations were approximately 7- and 22-fold higher, respectively, than the baseline concentrations. While both anesthetics reduced cortisol concentrations relative to those of nonanesthetized fish, these results suggest that MS-222 is an appropriate anesthetic to use during the initial 5 min of sedation and that metomidate hydrochloride is appropriate for longer periods of sedation.

Tunable mega-ampere electron current propagation in solids by dynamic control of lattice melt.

The influence of lattice-melt-induced resistivity gradients on the transport of mega-ampere currents of fast electrons in solids is investigated numerically and experimentally using laser-accelerated protons to induce isochoric heating. Tailoring the heating profile enables the resistive magnetic fields which strongly influence the current propagation to be manipulated. This tunable laser-driven process enables important fast electron beam properties, including the beam divergence, profile, and symmetry to be actively tailored, and without recourse to complex target manufacture.

Annular fast electron transport in silicon arising from low-temperature resistivity.

Fast electron transport in Si, driven by ultraintense laser pulses, is investigated experimentally and via 3D hybrid particle-in-cell simulations. A transition from a Gaussian-like to an annular fast electron beam profile is demonstrated and explained by resistively generated magnetic fields. The results highlight the potential to completely transform the beam transport pattern by tailoring the resistivity-temperature profile at temperatures as low as a few eV.