Turbulent stagnation in a Z-pinch plasma.

The ion kinetic energy in a stagnating plasma was previously determined by Kroupp et al. [Phys. Rev. Lett. 107, 105001 (2011)PRLTAO0031-900710.1103/PhysRevLett.107.105001] from Doppler-dominated line shapes augmented by measurements of plasma properties and assuming a uniform-plasma model. Notably, the energy was found to be dominantly stored in hydrodynamic flow. Here we advance a new description of this stagnation as supersonically turbulent. Such turbulence implies a nonuniform density distribution. We demonstrate how to reanalyze the spectroscopic data consistent with the turbulent picture and show that this leads to better concordance of the overconstrained spectroscopic measurements, while also substantially lowering the inferred mean density.

An audit of the management of childhood-onset growth hormone deficiency during young adulthood in Scotland.

BACKGROUND: Adolescents with childhood onset growth hormone deficiency (CO-GHD) require re-evaluation of their growth hormone (GH) axis on attainment of final height to determine eligibility for adult GH therapy (rhGH). AIM: Retrospective multicentre review of management of young adults with CO-GHD in four paediatric centres in Scotland during transition. PATIENTS: Medical records of 130 eligible CO-GHD adolescents (78 males), who attained final height between 2005 and 2013 were reviewed. Median (range) age at initial diagnosis of CO-GHD was 10.7 years (0.1-16.4) with a stimulated GH peak of 2.3 µg/l (0.1-6.5). Median age at initiation of rhGH was 10.8 years (0.4-17.0). RESULTS: Of the 130 CO-GHD adolescents, 74/130(57 %) had GH axis re-evaluation by stimulation tests /IGF-1 measurements. Of those, 61/74 (82 %) remained GHD with 51/74 (69 %) restarting adult rhGH. Predictors of persistent GHD included an organic hypothalamic-pituitary disorder and multiple pituitary hormone deficiencies (MPHD). Of the remaining 56/130 (43 %) patients who were not re-tested, 34/56 (61 %) were transferred to adult services on rhGH without biochemical retesting and 32/34 of these had MPHD. The proportion of adults who were offered rhGH without biochemical re-testing in the four centres ranged between 10 and 50 % of their total cohort. CONCLUSIONS: A substantial proportion of adults with CO-GHD remain GHD, particularly those with MPHD and most opt for treatment with rhGH. Despite clinical guidelines, there is significant variation in the management of CO-GHD in young adulthood across Scotland.

Pressure and energy balance of stagnating plasmas in z-pinch experiments: implications to current flow at stagnation.

Detailed spectroscopic diagnostics of the stagnating plasma in two disparate z pinches allow, for the first time, the examination of the plasma properties within a 1D shock wave picture, demonstrating a good agreement with this picture. The conclusion is that for a wide range of imploding-plasma masses and current amplitudes, in experiments optimizing non-Planckian hard radiation yields, contrary to previous descriptions the stagnating plasma pressure is balanced by the implosion pressure, and the radiation energy is provided by the imploding-plasma kinetic energy, rather than by the magnetic-field pressure and magnetic-field-energy dissipation, respectively.

Doppler measurement of implosion velocity in fast Z-pinch x-ray sources.

The observation of Doppler splitting in K-shell x-ray lines emitted from optically thin dopants is used to infer implosion velocities of up to 70 cm/µs in wire-array and gas-puff Z pinches at drive currents of 15-20 MA. These data can benchmark numerical implosion models, which produce reasonable agreement with the measured velocity in the emitting region. Doppler splitting is obscured in lines with strong opacity, but red-shifted absorption produced by the cooler halo of material backlit by the hot core assembling on axis can be used to diagnose velocity in the trailing mass.

Ion temperature and hydrodynamic-energy measurements in a Z-pinch plasma at stagnation.

The time history of the local ion kinetic energy in a stagnating plasma was determined from Doppler-dominated line shapes. Using independent determination of the plasma properties for the same plasma region, the data allowed for inferring the time-dependent ion temperature, and for discriminating the temperature from the total ion kinetic energy. It is found that throughout most of the stagnation period the ion thermal energy constitutes a small fraction of the total ion kinetic energy; the latter is dominated by hydrodynamic motion. Both the ion hydrodynamic and thermal energies are observed to decrease to the electron thermal energy by the end of the stagnation period. It is confirmed that the total ion kinetic energy available at the stagnating plasma and the total radiation emitted are in balance, as obtained in our previous experiment. The dissipation time of the hydrodynamic energy thus appears to determine the duration (and power) of the K emission.

Radiating shock measurements in the Z-pinch dynamic hohlraum.

The Z-pinch dynamic hohlraum is an x-ray source for high energy-density physics studies that is heated by a radiating shock to radiation temperatures >200 eV. The time-dependent 300-400 eV electron temperature and 15-35 mg/cc density of this shock have been measured for the first time using space-resolved Si tracer spectroscopy. The shock x-ray emission is inferred from these measurements to exceed 50 TW, delivering >180 kJ to the hohlraum.

Ion-kinetic-energy measurements and energy balance in a Z-pinch plasma at stagnation.

The ion-kinetic energy throughout K emission in a stagnating plasma was determined from the Doppler contribution to the shapes of optically thin lines. X-ray spectroscopy with a remarkably high spectral resolution, together with simultaneous imaging along the pinch, was employed. Over the emission period, a drop of the ion-kinetic energy down to the electron thermal energy was seen. Axially resolved time-dependent electron-density measurements and absolute intensities of line and continuum allowed for investigating, for the first time, each segment of the pinch, the balance between the ion-kinetic energy at the stagnating plasma, and the total radiation emitted. Within the experimental uncertainties, the ion-kinetic energy is shown to account for the total radiation.

Electron-temperature and energy-flow history in an imploding plasma.

The time-dependent radial distribution of the electron temperature in a 0.6 micros, 220-kA gas-puff z-pinch plasma is studied using spatially-resolved observations of line emission from singly to fivefold ionized oxygen ions during the plasma implosion, up to 50 ns before maximum compression. The temperature obtained, together with the previously determined radial distributions of the electron density, plasma radial velocity, and magnetic field, allows for studying the history of the magnetic-field energy coupling to the plasma by comparing the energy deposition and dissipation rates in the plasma. It is found that at this phase of the implosion, approximately 65% of the energy deposited in the plasma is imparted to the plasma radial flow, with the rest of the energy being converted into internal energy and radiation.

Developing national performance standards for local public health systems.

Since the beginning of the 1990s, public health has struggled to measure its performance and capacity to carry out the core functions of public health practice, while facing increasing challenges within the ever-changing landscape of healthcare delivery, bioterrorism response, emerging infections, and other threats to the public's health. The article describes the development of a set of national performance standards for measuring how effectively public health systems deliver the 10 Essential Public Health Services. The standards were developed through a practice-driven approach that incorporated comprehensive field testing and iterative revisions. The standards represent a national consensus framework for measuring important aspects of public health practice.

Safety and efficacy of allogeneic PBSC collection in normal pediatric donors: the pediatric blood and marrow transplant consortium experience (PBMTC) 1996-2003.

The use of peripheral blood stem cells (PBSC) for allogeneic transplants in adults has greatly increased. This trend is reflected in pediatrics, where healthy children increasingly are donating PBSC or donor lymphocyte infusion (DLI) via apheresis for use by ill siblings. There is a potential concern that the risks of PBSC collection may differ for pediatric donors. However, no large studies have assessed safety issues in this population. To address this need, we reviewed 218 (213 PBSC, five DLI) collections in 201 normal pediatric donors (8 months to 17 years, median 11.8 years) at 22 institutions in the Pediatric Blood and Marrow Transplant Consortium. Donors received a median of 4 days of growth factor, and mean collection yield was 9.1 x 10(6) CD34+ cells/kg recipient weight. Younger age, days of apheresis, and male gender predicted increased yield of CD34+ cells/kg donor weight. Growth factor-induced pain was mild and reported in less than 15% of patients. Most donors <20 kg (23/25, 92%) required PRBC priming of the apheresis machine. This experience with over 200 collections demonstrates that PBSC collection is safe in normal pediatric donors and desired CD34 cell yields are easily achieved. Younger children utilize more medical resources and children <20 kg usually require a single blood product exposure.

Immune reconstitution in pediatric stem-cell transplantation.

Hematopoietic stem-cell transplantation (HSCT) has successfully been used to cure many pediatric disorders. However, the immunologic alterations associated with transplantation result in profound immunodeficiencies in the transplant recipient, resulting in significant infectious morbidity and mortality. The precarious process of immune reconstitution in the transplant recipient is neither instantaneous nor complete, but influenced by multiple factors such as graft-versus-host disease (GVHD), conditioning regimen, patient age and underlying disease. Studies in pediatric HSCT have revealed unique attributes of immune recovery in pediatric transplant recipients. Future studies addressing these findings are needed to complement novel immunotherapies emerging from the field of transplant immunology.

Successful large volume leukapheresis on a small infant allogeneic donor.

We successfully performed a hematopoietic stem cell apheresis on the smallest allogeneic donor reported to date, a 6.1 kg female. After placement of a dialysis catheter in the left femoral vein, the COBE Spectra was primed with one unit of paternal whole blood. Heparin and anticoagulant citrate dextrose, solution A (ACD-A) were slowly administered to the patient. Ionized calcium levels were checked hourly and calcium gluconate was given for hypocalcemia. Coagulation parameters were checked throughout the procedure. We collected 4.4 x 10(6) CD34+ cells/kg (recipient). The donor tolerated the procedure well and was discharged the following day. Five months later, the child manifests no obvious late effects.

Long-term follow-up in hematopoietic stem-cell transplant patients.

Hematopoietic stem-cell transplantation (HSCT) has increasingly become an accepted treatment for many childhood diseases and disorders. Potential HSCT recipients can be children with hematological malignancies or solid tumors, as well as congenital and acquired disorders. In the past decade, the use of HSCT in the treatment of pediatric disorders has grown exponentially while advances in supportive care have improved survival rate, contributing to a rapidly growing population of transplant survivors. Although numerous similarities can be found between pediatric and adult long-term HSCT survivors, this article provides a brief overview of the pediatric patients, emphasizing the aspects of surveillance and late effects. Understanding the long-term complications that can occur after HSCT is important in determining the appropriate evaluations and medical treatment for the patient involved. The goal of this article is to assist caregivers in providing optimal care for long-term survivors of HSCT. The initial section of this work comprises the three major causes of late effects in HSCT. It will then encompass a system review of the different potential complications that are seen with HSCT.

Effect of shoe insert construction on foot and leg movement.

PURPOSE: The purpose of this study was to quantify changes in foot eversion and tibial rotation during running resulting from systematic changes of material composition of five shoe inserts of the same shape. METHODS: Tests were performed with 12 subjects. The inserts had a bilayer design using two different materials at the top and bottom of the insert. The functional kinematic variables examined in this study were the foot-leg in-eversion angle, beta, and the leg-foot tibial rotation, rho. Additionally, the subject characteristics of arch height, relative arch deformation, and active range of motion were quantified. The statistical analysis used was a two way repeated measures MANOVA (within trials and inserts). RESULTS: The average group changes resulting from the studied inserts in total shoe eversion, total foot eversion, and total internal tibial rotation were typically smaller than 1 degree when compared with the no-insert condition and were statistically not significant. The measured ranges of total foot eversion for all subjects were smallest for the softest and about twice as large for the hardest insert construction. Thus, the soft insert construction was more restrictive, forcing all feet into a similar movement pattern, whereas the harder combinations allowed for more individual variation of foot and leg movement and did not force the foot into a preset movement pattern. The individual results showed substantial differences between subjects and a trend: Subjects who generally showed a reduction of tibial rotation with all tested inserts typically had a flexible foot. However, subjects who generally showed an increase of tibial rotation typically had a stiff foot. CONCLUSIONS: The results of this study suggest that subject specific factors such as static, dynamic, and neuro-physiological characteristics of foot and leg are important to match specific feet and shoe inserts optimally.

Racial differences in performance of invasive cardiac procedures in a Department of Veterans Affairs Medical Center.

Racial differences have recently been described in hospital practice, most notably with regard to cardiac procedure utilization. To evaluate the possible reasons behind these differences, we analyzed statistics generated from a surgical referral conference at a large, tertiary care Veterans Affairs hospital between the years 1988 and 1996. In this setting, there is no financial incentive for physicians to recommend or perform invasive procedures, as all physicians are salaried employees of the Veterans Administration. Furthermore, all patients presented at conference have already had cardiac catheterization and are felt to be potential candidates for surgery or angioplasty. Cardiac therapeutic procedures (surgery or percutaneous transluminal coronary angioplasty) were recommended for 1075 of 1474 (72.9%) Caucasian patients and 207 of 322 (64.3%) African-American patients (odds ratio 1.497, 95% confidence interval 1.160 to 1.932, p = 0.0022). Of those patients presented with the option of an invasive procedure, 32 of 207 (15.4%) African-American patients and 89 of 1075 (8.3%) Caucasian patients refused any invasive procedure (odds ratio 2.026, 95% confidence interval 1.311 to 3.130, p = 0.0025). We conclude that reluctance by African-American patients to undergo invasive cardiac procedures may help explain observed disparities in race-related cardiac care.

A kinematic comparison of overground and treadmill running.

Treadmills are often used in research projects to simulate overground locomotion, assuming that locomotion is similar on a treadmill and overground. The purpose of this investigation was to determine whether a treadmill could be used to simulate overground locomotion. Twenty-two subjects ran on four different surfaces: overground and three treadmills that differed in size and power. The kinematics of the right leg and foot were studied using two high-speed Locam cameras (lateral and posterior view). The subjects ran in two different shoes at four different speeds (3.0-6.0 m.s-1). The differences in the kinematics between treadmill and overground running could be divided into systematic and subject dependent components. Subjects systematically planted their feet in a flatter position on the treadmill than overground. Most of the lower extremity kinematic variables, however, showed inconsistent trends for individual subjects, depending on the individual subject's running style, running speed, and shoe/treadmill situation. The differences were substantial. It is not yet understood how the human locomotor system adapts to a particular treadmill running situation. However, it is concluded that individual assessment of running kinematics on a treadmill for shoe or shoe orthotic assessment may possibly lead to inadequate conclusions about overground running.

Correlation between physical activity and the gait characteristics and ankle joint flexibility of the elderly.

The correlation between the type, duration and intensity of physical activity on the gait characteristics and the range of active ankle joint motion of the elderly were investigated in this study. Three-dimensional (3D) kinetic and kinematic assessments were performed on the normal walking patterns of 59 healthy elderly male and female subjects (aged 60-79 years). Gait analysis was performed using a high-speed video-based (3D) motion analysis system with synchronized ground-reaction force measurements. The maximal active range of motion (RoM) of the ankle joint complex of each subject was determined using an external six-degree-of-freedom flexibility assessment device. Physical activity levels were classified based on energy expenditure requirements. In general the results suggest that habitual level of physical activity did not have a significant effect on the kinetic or kinematic variables during walking, or the maximal ankle joint range of motion. Differences in ankle joint RoM and gait variables were found based on gender. No distinct benefit with respect to ankle joint range of motion or gait characteristics was provided with participation in higher-energy intensive physical activities in comparison to physical activities requiring low to moderate energy expenditures. It is speculated that the benefits of physical activity may be more pronounced in activities which demand rapid muscular strength and control movements such as recovering from a fall or obstacle avoidance. RELEVANCE: Participation in low-energy intensity activities provides the same benefits to ankle joint flexibility and locomotion, without the added risk of injury associated with high-energy intensity sports. This finding has important implications with respect to physical activity programmes for the elderly with an objective to maintain or improve independent mobility.