High-resolution inelastic x-ray scattering at the high energy density scientific instrument at the European X-Ray Free-Electron Laser.

We introduce a setup to measure high-resolution inelastic x-ray scattering at the High Energy Density scientific instrument at the European X-Ray Free-Electron Laser (XFEL). The setup uses the Si (533) reflection in a channel-cut monochromator and three spherical diced analyzer crystals in near-backscattering geometry to reach a high spectral resolution. An energy resolution of 44 meV is demonstrated for the experimental setup, close to the theoretically achievable minimum resolution. The analyzer crystals and detector are mounted on a curved-rail system, allowing quick and reliable changes in scattering angle without breaking vacuum. The entire setup is designed for operation at 10 Hz, the same repetition rate as the high-power lasers available at the instrument and the fundamental repetition rate of the European XFEL. Among other measurements, it is envisioned that this setup will allow studies of the dynamics of highly transient laser generated states of matter.

An approach for the measurement of the bulk temperature of single crystal diamond using an X-ray free electron laser.

We present a method to determine the bulk temperature of a single crystal diamond sample at an X-Ray free electron laser using inelastic X-ray scattering. The experiment was performed at the high energy density instrument at the European XFEL GmbH, Germany. The technique, based on inelastic X-ray scattering and the principle of detailed balance, was demonstrated to give accurate temperature measurements, within [Formula: see text] for both room temperature diamond and heated diamond to 500 K. Here, the temperature was increased in a controlled way using a resistive heater to test theoretical predictions of the scaling of the signal with temperature. The method was tested by validating the energy of the phonon modes with previous measurements made at room temperature using inelastic X-ray scattering and neutron scattering techniques. This technique could be used to determine the bulk temperature in transient systems with a temporal resolution of 50 fs and for which accurate measurements of thermodynamic properties are vital to build accurate equation of state and transport models.

Investigating off-Hugoniot states using multi-layer ring-up targets.

Laser compression has long been used as a method to study solids at high pressure. This is commonly achieved by sandwiching a sample between two diamond anvils and using a ramped laser pulse to slowly compress the sample, while keeping it cool enough to stay below the melt curve. We demonstrate a different approach, using a multilayer 'ring-up' target whereby laser-ablation pressure compresses Pb up to 150 GPa while keeping it solid, over two times as high in pressure than where it would shock melt on the Hugoniot. We find that the efficiency of this approach compares favourably with the commonly used diamond sandwich technique and could be important for new facilities located at XFELs and synchrotrons which often have higher repetition rate, lower energy lasers which limits the achievable pressures that can be reached.

Extreme Hardening of Pb at High Pressure and Strain Rate.

We study the high-pressure strength of Pb and Pb-4wt%Sb at the National Ignition Facility. We measure Rayleigh-Taylor growth of preformed ripples ramp compressed to ∼400 GPa peak pressure, among the highest-pressure strength measurements ever reported on any platform. We find agreement with 2D simulations using the Improved Steinberg-Guinan strength model for body-centered-cubic Pb; the Pb-4wt%Sb alloy behaves similarly within the error bars. The combination of high-rate, pressure-induced hardening and polymorphism yield an average inferred flow stress of ∼3.8 GPa at high pressure, a ∼250-fold increase, changing Pb from soft to extremely strong.

Inelastic response of silicon to shock compression.

The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported 'anomalous' elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. This model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature.

Grain-size-independent plastic flow at ultrahigh pressures and strain rates.

A basic tenet of material science is that the flow stress of a metal increases as its grain size decreases, an effect described by the Hall-Petch relation. This relation is used extensively in material design to optimize the hardness, durability, survivability, and ductility of structural metals. This Letter reports experimental results in a new regime of high pressures and strain rates that challenge this basic tenet of mechanical metallurgy. We report measurements of the plastic flow of the model body-centered-cubic metal tantalum made under conditions of high pressure (>100 GPa) and strain rate (∼10(7) s(-1)) achieved by using the Omega laser. Under these unique plastic deformation ("flow") conditions, the effect of grain size is found to be negligible for grain sizes >0.25 µm sizes. A multiscale model of the plastic flow suggests that pressure and strain rate hardening dominate over the grain-size effects. Theoretical estimates, based on grain compatibility and geometrically necessary dislocations, corroborate this conclusion.

Strength of shock-loaded single-crystal tantalum [100] determined using in situ broadband x-ray Laue diffraction.

The strength of shock-loaded single crystal tantalum [100] has been experimentally determined using in situ broadband x-ray Laue diffraction to measure the strain state of the compressed crystal, and elastic constants calculated from first principles. The inferred strength reaches 35 GPa at a shock pressure of 181 GPa and is in excellent agreement with a multiscale strength model [N. R. Barton et al., J. Appl. Phys. 109, 073501 (2011)], which employs a hierarchy of simulation methods over a range of length scales to calculate strength from first principles.

ORION laser target diagnostics.

The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

Measurements of electron transport in foils irradiated with a picosecond time scale laser pulse.

The heating of solid foils by a picosecond time scale laser pulse has been studied by using x-ray emission spectroscopy. The target material was plastic foil with a buried layer of a spectroscopic tracer material. The laser pulse length was either 0.5 or 2 ps, which resulted in a laser irradiance that varied over the range 10(16)-10(19) W/cm(2). Time-resolved measurements of the buried layer emission spectra using an ultrafast x-ray streak camera were used to infer the density and temperature conditions as a function of laser parameters and depth of the buried layer. Comparison of the data to different models of electron transport showed that they are consistent with a model of electron transport that predicts the bulk of the target heating is due to return currents.

Bragg diffraction using a 100 ps 17.5 keV x-ray backlighter and the Bragg diffraction imager.

A new diagnostic for measuring Bragg diffraction of petawatt-generated high-energy x rays off a laser-compressed crystal was designed and tested successfully at the Omega EP laser facility on static Mo and Ta (111) oriented single crystal samples using a 17.5 keV Mo Kα backlighter. The Bragg diffraction imager consists of a heavily shielded enclosure and a precisely positioned beam block attached to the enclosure by an aluminum arm. Fuji image plates are used as the x-ray detectors. The diffraction from Mo and Ta (222) crystal planes was clearly detected with a high signal-to-noise. This technique will be applied to shock- and quasi-isentropically loaded single crystals on the Omega EP laser.

Fast-ion production from short-pulse irradiation of ethanol microdroplets.

We report on the first detailed measurements of ion energy distributions from microdroplet targets under ultrashort (100 fs), intense (10(16) Wcm(-2)) laser irradiation. Protons with kinetic energies of up to 20 keV are produced in a strongly anisotropic microexplosion. Modeling of the incident electromagnetic field indicates strong spatial variations over the surface of the microdroplet. Detailed numerical modeling shows that nonuniform heating on a submicron scale causes temperature inhomogeneities and nonradial pressure gradients, which drive an energetic nonspherical expansion.

Assessing patient satisfaction with pain management through a continuous quality improvement effort.

A quasi-experimental study was conducted to evaluate patient satisfaction with pain management before and after a continuous quality improvement (CQI) project in a large, university medical center. The CQI project aim was to implement American Pain Society (APS) quality improvement guidelines regarding the recognition and prompt treatment of pain. A modified version of the questionnaire recommended by the APS Subcommittee on Quality Assurance Standards was used to survey 83 patients prior to implementation of the CQI effort and 89 patients one year later. Half of the patients reported moderate to severe pain both before and after the CQI project. Less than half reported complete relief of pain after treatment. Despite significant levels of pain and ineffective treatment, greater than 90% of patients reported being satisfied with pain management. Responses to open-ended questions were analyzed. Findings from the study are being used to develop a medical center-wide action plan to guide further CQI efforts to improve pain management.

Digitally assisted acromioplasty: the effect of interscalene block on this new surgical technique.

PURPOSE: Interscalene brachial plexus (ISBP) block has been shown to be safe and effective for shoulder surgery with significant benefits. The purpose of this study was to introduce the technique of digitally assisted acromioplasty and assess the effect of ISBP on rehabilitation. TYPE OF STUDY: Randomized controlled prospective trial. METHODS: In a randomized prospective trial of 40 patients undergoing acromioplasty under general anesthesia, 20 patients received an ISBP block (group 1) and 20 had no block (group 2). A digitally assisted acromioplasty was performed using a burr introduced via a posterior portal. The undersurface of the acromion was debrided, directing the burr with the surgeon's index finger introduced via a small lateral incision. Independent review was at day 1, day 2, week 1, week 6, and 1 year. RESULTS: Group 1 had significantly greater shoulder motion and shoulder score, and less pain and analgesic requirements on the first day. These differences did not persist. Both groups had improved pain and function over time compared with preoperative scores. CONCLUSIONS: ISBP provides superior initial results but does not offer any significant persistent functional or rehabilitative advantage in the medium to long term. Digitally assisted acromioplasty is simple to perform and does not violate the deltoid insertion.

Pain management: clinician survey and institutional needs assessment.

In 1996, 738 BUMC clinicians, representing 8 disciplines and >24 specialties, were surveyed using the Clinician Survey and Institutional Needs Assessment. This survey was developed by the Education Development Center, Inc., and distributed to 50 participating health care institutions in 21 states as part of the Mayday Pain Management Project. The BUMC findings revealed a gap between clinician knowledge and application of that knowledge to patient case scenarios. Clinician knowledge deficits included equianalgesic dosing, analgesic administration and dosing principles, nonpharmacological treatments, and assessment and management of pain in special populations. Fears and misconceptions about oversedation and drug abuse persist. Participants identified several legal and regulatory issues related to pain management, as well as improved collaboration among health care team members, as opportunities for professional growth. Based on these findings, BUMC has developed a pain management continuous quality improvement program.

Donor site morbidity after quadriceps tendon harvest for rotator cuff repair.

BACKGROUND: The central quadriceps tendon provides a useful free tendon graft, although the morbidity of harvesting it is unknown in elderly patients. METHODS: The donor site morbidities of 10 patients after central quadriceps tendon (CQT) graft harvest were reviewed for rotator cuff repair. Patients were reviewed by questionnaire and clinical examination at a minimum of 5 months after surgery. RESULTS: A majority of patients reported significant donor site pain and reduction in knee reliability and function. Six of 10 patients had reduced quadriceps power attributable to the graft harvest. CONCLUSION: The harvesting of the CQT graft is associated with significant morbidity, especially in an elderly population with limited functional reserve.

Effect of subcutaneous granulocyte colony-stimulating factor injectate volume on drug efficacy, site complications, and client comfort.

PURPOSE/OBJECTIVES: To determine the effect of administering 1.6 ml (480 mcg) of granulocyte colony-stimulating factor (G-CSF) in one subcutaneous injection or two injections of 0.8 ml each. DESIGN: Experimental. SETTING: 27-bed bone marrow transplant intensive care unit of a metropolitan, university medical center in the southwestern United States. SAMPLE: Nonprobability; 76 women who received high-dose chemotherapy for breast cancer followed by hemopoietic rescue. METHODS: Subjects were randomized into an experimental group that received one injection per 480 mcg dose and a control group that received two injections per 480 mcg dose administered by research associates using a standardized injection technique. MAIN RESEARCH VARIABLES: Injectate volume. The number of days post-transplant until the absolute neutrophil count (ANC) returned to 1,000/mm3, the incidence and surface area in mm2 of site complications, and scores on Tursky's Quantified Pain Descriptor immediately following the injection(s). FINDINGS: No significant difference existed between the two groups in ANC recovery time, frequency or size of site complications, or intensity, reaction, or sensation of discomfort reported. CONCLUSIONS: Administering 1.6 ml doses of G-CSF in one injection instead of two does not result in slower ANC recovery, induration, more frequent or larger bruises or areas of erythema, or greater client discomfort. IMPLICATIONS FOR NURSING PRACTICE: Administering one injection instead of two may decrease patients' anxiety, the nursing time needed for preparation and administration of injections, patient instruction for self-administration, the potential for contamination of vials or loss of dose, and the cost of supplies.

A comparative analysis of Orem's self-care model and Peplau's interpersonal theory.

The process of choosing a nursing model or theory to guide one's clinical practice, curriculum development or theoretical framework for research can be facilitated by analysis of and comparison of existing theories, with each other and then with one's personal philosophies. This paper summarizes the major concepts and assumptions of Dorothea Orem's self-care model and Hildegard Peplau's interpersonal theory, and then compares the two for similarities and differences in their origins of theory development, meanings related to nursing metaparadigm concepts, logical adequacy, usefulness and generalizability, parsimony and testability.