Onset of hydrodynamic mix in high-velocity, highly compressed inertial confinement fusion implosions

Deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility have demonstrated yields ranging from 0.8 to 7×10(14), and record fuel areal densities of 0.7 to 1.3 g/cm2. These implosions use hohlraums irradiated with shaped laser pulses of 1.5-1.9 MJ energy. The laser peak power and duration at peak power were varied, as were the capsule ablator dopant concentrations and shell thicknesses. We quantify the level of hydrodynamic instability mix of the ablator into the hot spot from the measured elevated absolute x-ray emission of the hot spot. We observe that DT neutron yield and ion temperature decrease abruptly as the hot spot mix mass increases above several hundred ng. The comparison with radiation-hydrodynamic modeling indicates that low mode asymmetries and increased ablator surface perturbations may be responsible for the current performance.

Hot-spot mix in ignition-scale inertial confinement fusion targets

Mixing of plastic ablator material, doped with Cu and Ge dopants, deep into the hot spot of ignition-scale inertial confinement fusion implosions by hydrodynamic instabilities is diagnosed with x-ray spectroscopy on the National Ignition Facility. The amount of hot-spot mix mass is determined from the absolute brightness of the emergent Cu and Ge K-shell emission. The Cu and Ge dopants placed at different radial locations in the plastic ablator show the ablation-front hydrodynamic instability is primarily responsible for hot-spot mix. Low neutron yields and hot-spot mix mass between 34(-13,+50)  ng and 4000(-2970,+17 160)  ng are observed.

Diagnosing radiative shocks from deuterium and tritium implosions on NIF

During the recent ignition tuning campaign at the National Ignition Facility, layered cryogenic deuterium and tritium capsules were imploded via x-ray driven ablation. The hardened gated x-ray imager diagnostic temporally and spatially resolves the x-ray emission from the core of the capsule implosion at energies above ~8 keV. On multiple implosions, ~200-400 ps after peak compression a spherically expanding radiative shock has been observed. This paper describes the methods used to characterize the radial profile and rate of expansion of the shock induced x-ray emission.

Measurement of electron temperature of imploded capsules at the National Ignition Facility

The electron and ion temperatures of the imploded core plasma are two of the most important metrics of inertial confinement fusion experiments. We have developed a technique for inferring electron temperatures from the contrast of x-ray images observed through a group of x-ray filters. Generally, the plasma electron temperature exhibits spatial and temporal variations, so time-averaged and time-resolved measurements are expected to yield somewhat different results. By analyzing the intensity of images observed with both a time-integrated detector (imaging plates) and a time-resolved detector (gated micro-channel plate), we found the electron temperature observed from x-ray images to be systematically higher than the ion temperature inferred from fusion neutron spectroscopy.

Role of MYH9 and APOL1 in African and non-African populations with lupus nephritis

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production and organ damage. Lupus nephritis (LN) is one of the most severe manifestations of SLE. Multiple studies reported associations between renal diseases and variants in the non-muscle myosin heavy chain 9 (MYH9) and the neighboring apolipoprotein L 1 (APOL1) genes. We evaluated 167 variants spanning MYH9 for association with LN in a multiethnic sample. The two previously identified risk variants in APOL1 were also tested for association with LN in European-Americans (EAs) (N = 579) and African-Americans (AAs) (N = 407). Multiple peaks of association exceeding a Bonferroni corrected P-value of P < 2.03 × 10(-3) were observed between LN and MYH9 in EAs (N = 4620), with the most pronounced association at rs2157257 (P = 4.7 × 10(-4), odds ratio (OR) = 1.205). A modest effect with MYH9 was also detected in Gullah (rs8136069, P = 0.0019, OR = 2.304). No association between LN and MYH9 was found in AAs, Asians, Amerindians or Hispanics. This study provides the first investigation of MYH9 in LN in non-Africans and of APOL1 in LN in any population, and presents novel insight into the potential role of MYH9 in LN in EAs.

Experimental study of neutron induced background noise on gated x-ray framing cameras

A temporally gated x-ray framing camera based on a proximity focus microchannel plate is one of the most important diagnostic tools of inertial confinement fusion experiments. However, fusion neutrons produced in imploded capsules interact with structures surrounding the camera and produce background to x-ray signals. To understand the mechanisms of this neutron induced background, we tested several gated x-ray cameras in the presence of 14 MeV neutrons produced at the Omega laser facility. Differences between background levels observed with photographic film readout and charge-coupled-device readout have been studied.

Measuring symmetry of implosions in cryogenic Hohlraums at the NIF using gated x-ray detectors (invited)

Ignition of imploding inertial confinement capsules requires, among other things, controlling the symmetry with high accuracy and fidelity. We have used gated x-ray imaging, with 10 μm and 70 ps resolution, to detect the x-ray emission from the imploded core of symmetry capsules at the National Ignition Facility. The measurements are used to characterize the time dependent symmetry and the x-ray bang time of the implosion from two orthogonal directions. These measurements were one of the primary diagnostics used to tune the parameters of the laser and Hohlraum to vary the symmetry and x-ray bang time of the implosion of cryogenically cooled ignition scale deuterium/helium filled plastic capsules. Here, we will report on the successful measurements performed with up to 1.2 MJ of laser energy in a fully integrated cryogenics gas-filled ignition-scale Hohlraum and capsule illuminated with 192 smoothed laser beams. We will describe the technique, the accuracy of the technique, and the results of the variation in symmetry with tuning parameters, and explain how that set was used to predictably tune the implosion symmetry as the laser energy, the laser cone wavelength separation, and the Hohlraum size were increased to ignition scales. We will also describe how to apply that technique to cryogenically layered tritium-hydrogen-deuterium capsules.

A hardened gated x-ray imaging diagnostic for inertial confinement fusion experiments at the National Ignition Facility

A gated x-ray detector is under development for use at the National Ignition Facility that is intended to provide plasma emission images in the presence of neutron yields up to 10(15) expected during inertial confinement fusion experiments with layered cryogenic targets. These images are expected to provide valuable time-resolved measurements of core and fuel symmetries. Additional capabilities of this instrument will include the ability to make spatially resolved electron temperature measurements. A description of this instrument and its operation is given with emphasis on features that differentiate it from previous designs.

Maternal parenting stress and its correlates in families with a young child with cerebral palsy

OBJECTIVE

To investigate factors predicting parenting stress in mothers of pre-school children with cerebral palsy.

METHOD

Eighty mothers and children participated. Mothers completed the Parenting Stress Index (PSI) and the following measures of family functioning: family support, family cohesion and adaptability, coping strategies, family needs and locus of control. Children were assessed using the Griffiths Scales and the Gross Motor Function measure. The child's home environment was assessed using Home Observation for Measuring the Environment.

RESULTS

Mothers had higher mean total PSI scores than the means for the typical sample; 43% had total PSI scores above the threshold for clinical assessment. Cluster analysis demonstrated five distinct clusters of families, more than half of whom were coping well. High stress items were role restriction, isolation and poor spouse support, and having a child who was perceived as less adaptable and more demanding. Lower stress items indicated that this sample of mothers found their children emotionally reinforcing and had close emotional bonds. Regression analysis showed that the factors most strongly related to parenting stress levels were high family needs, low family adaptability and cognitive impairment in the child.

CONCLUSIONS

The results confirmed the individuality of families, and that individual characteristics of coping and feeling in control, together with family support and cohesion, are associated with variation in amount of stress experienced in parenting a child with cerebral palsy.

Haemolytic anaemia in a multi-ethnic cohort of lupus patients: a clinical and serological perspective

Systemic lupus erythematosus is a chronic autoimmune disease that can be associated with a variety of haematological manifestations. We identified 76 patients with haemolytic anaemia in a cohort of 1251 unrelated female lupus patients enrolled in our studies. The presence of the various American College of Rheumatology clinical criteria for lupus and serological specificities were determined in lupus patients with haemolytic anaemia and compared with a group of race-matched control lupus patients without haemolytic anaemia. Clinical data were obtained from medical records, and serological specificities were determined in our clinical immunology laboratory at OMRF. The presence of haemolytic anaemia in lupus patients was associated with a higher frequency of proteinuria (OR = 2.70, P = 0.000031), urinary cellular casts (OR = 2.83, P = 0.000062), seizures (OR = 2.96, P = 0.00024), pericarditis (OR = 2.21, P = 0.0019), pleuritis (OR = 1.72, P = 0.028) and lymphopenia (OR = 1.79, P = 0.015). These findings were independent of the presence of thrombocytopenia, which was approximately five times more common in lupus patients with haemolytic anaemia. Lupus patients with haemolytic anaemia were about 8 years younger than lupus patients without haemolytic anaemia at the time of disease onset (P = 0.000001). In the absence of thrombocytopenia, lupus patients with haemolytic anaemia were approximately two times more likely to have anti-dsDNA antibodies (P = 0.024). The presence of haemolytic anaemia is associated with a subset of lupus characterized by a younger age of disease onset, and a more severe disease with a higher likelihood of renal involvement, seizures, serositis and other cytopenias.

Sulpha allergy in lupus patients: a clinical perspective

Abstract

Systemic lupus erythematosus is a chronic, relapsing autoimmune disease that can affect multiple organ systems. An increased prevalence of drug allergy has been reported in lupus patients compared with the general population. Using a cohort of 417 lupus patients, we found a history of sulpha allergy in 27.3% of patients. European-American lupus patients with sulpha allergy are about two times more likely to suffer from lymphopenia, two times more likely to have anti-Ro autoantibody, and four times less likely to have anti-nRNP antibodies compared with lupus patients without a reported sulpha allergy ( P = 0.0075, 0.025, and 0.032, respectively). In African-American lupus patients, a history of sulpha allergy was associated with over three times increased odds of developing pericarditis ( P = 0.005).

Altered multiaxial mechanical properties of the porcine anterior lens capsule cultured in high glucose

Hyperglycemia can alter the mechanical properties of tissues through the formation of advanced glycation endproducts in matrix proteins that have long half-lives. We used a custom experimental system and subdomain finite element method to quantify alterations in the regional multiaxial mechanical properties of porcine lens capsules that were cultured for 8 or 14 weeks in high glucose versus control media. Findings revealed that high glucose significantly stiffened the capsules in both the circumferential and the meridional directions, but it did not affect the known regional variations in anisotropy. Such information could be important in the design of both improved clinical procedures and intraocular implants for diabetic patients.

One in five Californians were uninsured in 2005 despite modest gains in coverage

Six and one-half million Californians were uninsured for all or some of 2005, a number that is as large as the combined populations of nine other states. The number of uninsured represented one in five children and nonelderly adults, a rate that was slightly lower than in 2003 due to California's tight labor markets and expanding enrollment and retention in California's public coverage programs for children. These marginal improvements are unlikely to continue unabated given the instability of employment-based insurance coverage in the face of rising costs. In this policy brief, we compare insurance coverage over time using the California Health Interview Surveys conducted in 2001, 2003 and 2005. We look at the type of coverage over the past 12 months for both children and nonelederly adults.

Performance of young people with Down syndrome on the Leiter-R and British picture vocabulary scales

BACKGROUND

The British picture vocabulary scales (BPVS-II) and the Leiter international performance scales (Leiter-R), both restandardised in 1997, are often used in experimental studies to match individuals with intellectual impairment. Both provide a brief measure of mental age, and cover a wide ability range using a simple format. The BPVS-II assesses verbal comprehension and the Leiter nonverbal abilities. The issue is which to choose. People with Down syndrome (DS), for example, have particular problems in language and so the BPVS may provide an underestimation of ability.

METHOD

The present study investigated this by comparing the performance of 46 young people with DS (21 females, 25 males, mean age 19 years 10 months) on the BPVS-II (verbal mental age - VMA) and the Leiter-R brief IQ (nonverbal mental age - NVMA).

RESULTS

Contrary to expectations VMAs were significantly higher than NVMAs (6 years 6 months and 5 years 2 months, respectively). There was a significant correlation of 0.61 between the VMA and NVMA, and both discriminated participants at all levels of ability. However, the Leiter-R brief IQ scores provided poor discrimination at the bottom end of the IQ range (IQ 36).

CONCLUSION

Both the BPVS-II and the Leiter-R provide mental age equivalent scores that are useful for plotting developmental progress, although absolute mental ages may differ.

Late onset neonatal anaemia due to maternal anti-Ge: possible association with destruction of eythroid progenitors

There have been no reports of severe haemolytic disease of the newborn (HDN) due to Gerbich (Ge) antibodies. Two babies with HDN due to anti-Ge3, both born to the same mother, are described. The anti-Ge appeared in the first pregnancy and was not detectable in the first trimester, the babies' reticulocyte and bilirubin values were not greatly elevated (similar to HDN due to Kell antibodies), and the anaemia in both cases was either not apparent or not severe until 2 to 4 weeks after birth. Ge antigens are found on glycophorins (GPs) C and D; GPC, like Kell, has been shown to be expressed early on erythroid progenitor cells. The maternal anti-Ge3 was shown to promote phagocytosis of Ge+ early erythroid progenitors by monocytes (similar to what has been reported with anti-K and K+ progenitor cells). Thus, anti-Ge3 may cause immune destruction of erythroid progenitors and possibly suppression of erythropoiesis (which would explain the reticulocyte and bilirubin values seen in both cases). Anti-Ge3 appears to be capable of causing severe HDN. We suggest that babies born to mothers with anti-Ge should have their haemoglobin concentrations monitored for signs of anaemia for several weeks after birth. Functional assays may prove useful.

Invasive fungal infections in pediatric oncology patients: 11-year experience at a single institution

The purpose of this study was to determine the incidence of fungal infections in pediatric hematology and oncology (PHO) patients and to describe variations regarding site of infection, organisms, and mortality. The records of 1,052 patients presenting to the UCLA PHO service with various malignancies from 1991 to 2001 were retrospectively reviewed. No patient received invasive antifungal prophylaxis. Transplant patients were excluded. The 11-year incidence of fungal infections in this pediatric oncology cohort was 4.9%. There was a linear increase in the incidence of fungal infections from 2.9% to 7.8% between 1996 and 2001 (P = 0.001). Patients with acute leukemia represented 36% of the population but had a disproportionate incidence (67%) of fungal infections. Adolescents had twice the expected incidence of infection (P < 0.0001). Overall, Candida sp. was the major pathogen. Over time, a trend of fewer infections caused by Candida and more due to Aspergillus was noted. Blood-borne infections decreased over time, while those in the urinary and respiratory tracts increased (P = 0.04). Sixty-two percent of infections occurred in neutropenic patients. PHO patients had an overall mortality of 21%, but those with fungal infections experienced a 2.6-fold higher mortality that was not attributable to infections alone. Empiric antifungal therapy had no effect on mortality rates. Concurrent nonfungal infections did not increase mortality rates. The incidence of fungal infections increased over time, possibly as a result of advances in antibacterial and chemotherapeutic regimens. Adolescents and patients with leukemia were especially at risk. Fungal infections are a poor prognostic factor, independent of fungal-related mortality. New diagnostic methods allowing for early detection and treatment as well as more effective therapies are needed.

The expression of pain in infants with developmental delays

OBJECTIVE

To explore how infants with developmental delays express pain, we analysed facial expressions of infants receiving their routine immunization at around 4-6 months developmental age. The sample included eight infants with developmental disabilities (mean developmental age 4.8 months) and 30 typically developing infants (mean age 4 months). The Maximally Discriminative Facial Movement Coding system was used to code infant facial expressions during immunization.

RESULTS

The pain expression was by far the most common of all facial expressions following immunization for both groups of infants. Those with disabilities produced significantly fewer discrete high-intensity expressions of pain, and significantly more blended expressions than typically developing infants. Expressions of fear, sadness and anger were relatively infrequent in both groups. Infants with disabilities used their upper face less often than typically developing infants, and their mid face was uncodeable more often.

CONCLUSION

Infants with developmental delays were likely to show pain in facial expressions less clearly than typically developing infants. It is important for health care professionals to be aware that this may be the case when considering the administration of analgesia for such children.

Mastery motivation in children with Down syndrome

Mastery motivation refers to the intrinsic motivation children have to interact with their environments in order to learn about them. It appears early in life, and has been regarded by many researchers as a key motivator for development. It has also been suggested that young school age children with Down syndrome show lowered motivation to perform tasks. It is important to know if this low motivation is present from the start, or develops as a result of environmental experiences; studies of mastery motivation have been one way of investigating this issue. However definitions of mastery motivation, and hence empirical studies, have varied. Thus this paper starts by revisiting the issues surrounding definition and measurement. There is general agreement on some issues: that mastery motivation is intrinsic, that it is manifest in different behaviours as the child develops, that there are individual differences in mastery behaviour, and that these are affected by environmental factors. There is also current agreement that it is essential to remove the confound of differing levels of developmental competence by using individualized measurement. However there is disagreement about which behaviours best index mastery motivation. Some empirical work with infants with Down syndrome is reviewed, and results from a recent longitudinal study on the development of mastery motivation are presented. The results concurred with most others in the recent literature, suggesting that low mastery motivation is not inevitable in infancy in Down syndrome. Infants with Down syndrome showed similar patterns of development as typically developing children, with slight delays. It is argued that longitudinal studies are needed to demonstrate such patterns of development. As the children developed from 6 to 24 months mental age there was no evidence for decreasing levels of mastery motivation. Thus there was no support for the view that more failure experiences impact on levels of mastery motivation. In contrast caregivers did see their young children with Down syndrome as less object mastery oriented than did caregivers of typically developing children. The caregivers of children with Down syndrome were also significantly more directive in their interactions with their children, and there was some suggestion that individual differences in mastery behaviours were related to levels of mastery behaviours in their children. The final section speculates on reasons for these results, and makes suggestions for future work.

Heparin-binding EGF-like growth factor decreases inducible nitric oxide synthase and nitric oxide production after intestinal ischemia/reperfusion injury

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been shown to protect intestine from ischemia/reperfusion (I/R) injury in vivo and to down-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in intestinal epithelial cells in vitro. The present study was undertaken to investigate whether HB-EGF could modulate the iNOS/NO axis after total midgut I/R injury in rats. I/R injury induced a significant increase in iNOS gene expression (quantified by real-time RT-PCR) and protein production (detected by western blots), as well as elevation of serum NO levels (measured by chemiluminescence assay). Nitrotyrosine (NT) and iNOS production colocalized immunohistochemically, with positive staining found mainly in villous and crypt epithelial cells, as well as ganglion cells. Intraluminal administration of HB-EGF 45 min after the start of a 90-min ischemic interval significantly decreased I/R-induced iNOS gene expression and protein production, as well as serum NO levels. Immunohistochemically, HB-EGF administration led to elimination of iNOS and NT staining in crypt epithelial cells and ganglion cells, with only weak staining that remained in villous epithelial cells. Thus, HB-EGF protects the intestine from I/R injury, at least partially, through down-regulation of the iNOS/NO/NT pathway, a mechanism that is central to I/R injury in multiple organ systems.

Women's reluctance to seek help for stress incontinence during pregnancy and following childbirth

OBJECTIVE

to identify whether women were made aware of stress incontinence around the time of childbirth, whether symptomatic women sought help from professionals caring for them at this time, to look at what help they receive in the first instance and to understand why some of those experiencing it chose not to seek help.

DESIGN

a qualitative survey was conducted using semi-structured interviews.

SETTING

interviews were conducted in participants' own homes.

PARTICIPANTS

42 women who reported symptoms of stress incontinence at eight weeks postpartum, and 15 women who were symptomatic one year following the birth of their baby.

FINDINGS

women were reluctant to seek help, although they were often inconvenienced and troubled by the condition. This was predominantly due to the nature of the condition itself, although the relationship with their health care professionals was also a consideration in some cases. The majority of women were not provided with information on the condition but wanted health professionals to provide a warning that the condition could occur. They also wanted health professionals to seek out information about symptoms, rather than the women themselves having to broach the subject. The first line of treatment at this time was usually a recommendation to perform pelvic floor exercises.

IMPLICATIONS FOR PRACTICE

health professionals caring for women during pregnancy or following the birth of their baby need to raise awareness of the condition, the treatment available, and to be pro-active in seeking out those experiencing incontinence rather than expecting women to approach them for help.

The instruction in pelvic floor exercises provided to women during pregnancy or following delivery

OBJECTIVES

to examine the instruction in pelvic floor exercises given to women during pregnancy or following delivery, to assess the quality of any instruction provided, and to consider these in light of the women's views about the service.

DESIGN

a postal questionnaire was sent to a sample of women when they reached 34 weeks of pregnancy and a second at 8 weeks postpartum. A sub-sample of women who reported symptoms of stress incontinence at 8 weeks postpartum were interviewed about the instruction in pelvic floor exercises that they received during their pregnancy, or in the puerperium.

PARTICIPANTS

of the 918 women who were sent the first questionnaire, 717 returned it completed (78%). Five-hundred-and-seventy-two of 894 women (64%) completed the second questionnaire. Forty-two of 179 symptomatic women (23%) took part in an interview.

FINDINGS

55% of women received some form of instruction in pelvic floor exercises by 34 weeks of pregnancy. Eighty-six percent received instruction following birth. The way the information was given varied, ranging from a brief reminder, to exercising in a class with an instructor. The information was provided by a range of health professionals, and no single profession appeared to undertake responsibility for the service. As a result, the views of the service varied. A few women reported that they had received good quality instruction, others were critical of it, and a small number reported that they had received no instruction at all. The widespread practice of leaving a leaflet by the women's beds during their stay in hospital, was criticised by a large proportion of the women.

KEY CONCLUSION

the instruction in pelvic floor exercises by health service professionals was provided on an ad hoc basis. In many instances, the programme of instruction did not meet recommendations made in the literature. It is likely that the success of randomised controlled trials reported in the literature would not be repeated in the 'real world' Implications for practice: there is a need for the service to be reorganised so that all women receive high-quality instruction during pregnancy, with a reminder to exercise following birth. This could help to prevent, or relieve, the symptoms of stress incontinence that frequently occur at these times.