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1.
Rev Sci Instrum ; 92(4): 043507, 2021 Apr 01.
Article in English | MEDLINE | ID: mdl-34243402

ABSTRACT

During the past few years, the Orion high-resolution x-ray spectrometers have been successful tools for measuring x-ray spectra from plasmas generated in the Orion laser facility. Duplicate spectrometers also operate successfully at the Livermore EBIT-I and SuperEBIT electron beam ion traps for measuring x-ray polarization. We have recently implemented very high-quality, optically bonded, spherically bent quartz crystals to remove the structure in the x-ray image that had been observed in earlier measurements. The structure had been caused by focusing defects and limited the accuracy of our measurements. We present before and after images that show a drastic improvement. We, furthermore, have implemented a spherically bent potassium acid phthalate (KAP) crystal on one of our spectrometers. The KAP crystal was prepared in a similar fashion, and we present measurements of the N Ly-ß and Ne Lyß lines taken in first- and second-order reflections at 600 and 1200 eV, respectively. These measurements confirm that KAP crystals can be produced at a quality suitable for extending the spectral coverage to wavelengths longer than those accessible by different quartz crystals, especially those that cover the astrophysically important lines of iron.

2.
Mult Scler Relat Disord ; 38: 101481, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31756608

ABSTRACT

BACKGROUND: Mastery is the sense of being in control of one's life and improvement in mastery may help to enhance quality of life. Little research has explored mastery in people with multiple sclerosis (MS), including its association with quality of life. OBJECTIVE: To explore the association between mastery and health-related quality of life (HRQOL) in people with MS. METHOD: Two cross-sectional cohorts of adults with MS (n = 1401 and n = 573), recruited through convenience sampling, completed an online survey which measured mastery using the Pearlin Mastery Scale, physical and mental HRQOL via physical and mental health composite scores of MSQOL-54, along with other covariates, including demographics, clinical characteristics and lifestyle factors. Linear regression assessed associations between mastery and physical HRQOL adjusting for age, sex, education, disability and depression, and between mastery and mental HRQOL adjusting for age, sex, education, disability and clinically significant fatigue. RESULTS: Greater mastery score was associated with higher physical and mental HRQOL in both cohorts, such that a one-point increase in the PMS was associated with an increase of 2.9 (95% Confidence Interval (CI): 2.6, 3.1) and 2.8 points (95% CI: 2.4, 3.2) in the means of physical HRQOL score in the first and second cohorts respectively, and a 2.9-point (95% CI: 2.7, 3.1) and 3.1-point (95% CI: 2.7, 3.4) increase in the means of mental HRQOL score. A dose-dependent relationship was demonstrated between a quartile categorical mastery variable and both physical and mental HRQOL in both cohorts. Mastery was associated with all subscores of both physical and mental HRQOL. CONCLUSIONS: Greater mastery is associated with better physical and mental quality of life. Efforts to improve the sense of self control and agency of people with MS may have benefits for their quality of life, even despite clinical features of the illness.


Subject(s)
Multiple Sclerosis/psychology , Quality of Life/psychology , Self Efficacy , Adult , Cross-Sectional Studies , Disabled Persons , Female , Humans , Male , Middle Aged , Severity of Illness Index
3.
Eur J Neurol ; 26(1): 142-154, 2019 01.
Article in English | MEDLINE | ID: mdl-30133057

ABSTRACT

BACKGROUND AND PURPOSE: We aimed to estimate the prevalence of perceived cognitive impairment (PCI) and explore its associations with lifestyle and disease characteristics in a large international cohort of people with multiple sclerosis (MS). METHODS: This study was a cross-sectional analysis. Participants rated their cognitive function over the preceding 4 weeks using four questions in a subscale within the Multiple Sclerosis Quality of Life questionnaire (MSQOL-54). These questions assessed perceived concentration, attention and memory by the patient and family/friends. Four definitions of PCI were derived, ranging from lowest to highest specificity. Associations with PCI were assessed by log-binomial regression. RESULTS: The prevalence of PCI in our sample ranged from 41.0% (95% confidence interval, 39.0-43.0) using the least-specific definition to 11.6% (95% confidence interval, 10.3-12.9) using the most specific definition. A number of factors were associated with PCI, increasing in magnitude as the definition specificity increased, including positive associations for smoking and body mass index, whereas physical activity, dietary quality and use of vitamin D/omega-3 supplements were inversely associated with PCI. CONCLUSIONS: Our study reports associations between healthy lifestyle behaviours and PCI in people with MS. Although reverse causality is a potential explanation for our findings, previous studies have shown comparable associations with healthy lifestyle and MS onset and progression. Subject to external validation, these results suggest benefits realized from a healthy lifestyle in people with MS.


Subject(s)
Cognition , Life Style , Multiple Sclerosis/psychology , Adolescent , Adult , Aged , Aged, 80 and over , Attention , Cognition Disorders/etiology , Cognition Disorders/psychology , Cohort Studies , Cross-Sectional Studies , Female , Health Surveys , Humans , Male , Memory , Middle Aged , Quality of Life , Self Report , Young Adult
4.
Rev Sci Instrum ; 89(10): 10F120, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30399793

ABSTRACT

The Orion high-resolution x-ray (OHREX) spectrometer has been a successful tool for measuring the shapes of density-broadened spectral lines produced in short-pulse heated plasmas at the Orion laser facility. We have recently outfitted the instrument with a charge-couple device (CCD) camera, which greatly increased the accuracy with which we can perform line-shift measurements. Because OHREX is located on the outside of the Orion target chamber, no provisions for the shielding of electromagnetic pulses are required. With the CCD, we obtained a higher signal-to-noise ratio than we previously obtained with an image-plate detector. This allowed us to observe structure in the image produced by the diffraction from the two OHREX crystals, which was highly reproducible from shot to shot. This structure will ultimately limit the accuracy of our spectroscopic measurements.

5.
Plant Dis ; 101(7): 1300-1305, 2017 Jul.
Article in English | MEDLINE | ID: mdl-30682946

ABSTRACT

Solanum sisymbriifolium, the litchi tomato, is a perennial herbaceous plant from South America that is used as a trap crop to reduce soilborne populations of the pale cyst nematode Globodera pallida, an important potato pathogen. Possible interactions of soilborne potato pathogens Verticillium dahliae and Colletotrichum coccodes with litchi tomato are unknown, yet important for potato production if litchi tomato is to be planted as a trap crop. The goal of this research was to quantitatively assess if litchi tomato is a potential inoculum source for C. coccodes and V. dahliae by comparing colony forming units (CFU) observed in litchi tomato to susceptible and resistant potato cultivars. The potato cvs. Alturas (P = 0.0003), Ranger Russet (P = 0.0193), and Russet Norkotah (P = 0.0022) produced more CFUs of the potato pathotype of V. dahliae than litchi tomato the first of two years of greenhouse trials. Significantly more CFUs of the potato pathotype of V. dahliae were quantified from stems and roots of only cv. Russet Norkotah compared with litchi tomato (P = 0.0001) in the second year. The CFUs for C. coccodes varied between litchi tomato and the potato cvs., perhaps due to varying levels of resistance since litchi tomato is from a selected intermated seed source. Based on these data, the effect of litchi tomato in rotation with potato is likely to have limited effect on the proliferation of V. dahliae or C. coccodes populations in the soil when compared with a susceptible potato cultivar.

6.
Br Poult Sci ; 58(2): 139-143, 2017 Apr.
Article in English | MEDLINE | ID: mdl-27845558

ABSTRACT

1. Hatching success of ostrich eggs is poor (50-60% of fertile eggs). The current study was designed to identify the timing of key stages in the development of the ostrich embryo. 2. Growth of both embryo and wing length during 42 d of incubation was comparable and approximately linear, with a more or less weekly doubling in size up to 35 d of incubation. 3. The embryo eye size increased more rapidly than beak length and reached a maximum of ~16.2 mm by 28 d of incubation, whereas beak length increased continuously until hatching at 42 d. 4. Linear regression equations were derived from morphometric measurements of embryos between 7 and 42 d. 5. Information stemming from these results can be used to estimate the age of dead-in-shell embryos in an attempt to identify timing of incubation problems that potentially result in low hatchability of fertile eggs.


Subject(s)
Embryonic Development , Struthioniformes/embryology , Animals , Embryo, Nonmammalian , Struthioniformes/growth & development
7.
Rev Sci Instrum ; 87(11): 11E337, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27910339

ABSTRACT

We present synthetic transmission spectra generated with PrismSPECT utilizing both the ATBASE model and the Los Alamos opacity library (OPLIB) to evaluate whether an alternative choice in atomic data will impact modeling of experimental data from radiation transport experiments using Sc-doped aerogel foams (ScSi6O12 at 75 mg/cm3 density). We have determined that in the 50-200 eV Te range there is a significant difference in the 1s-3p spectra, especially below 100 eV, and for Te = 200 eV above 5000 eV in photon energy. Examining synthetic spectra generated using OPLIB with 300 resolving power reveals spectral sensitivity to Te changes of ∼3 eV.

8.
Rev Sci Instrum ; 87(6): 063501, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27370448

ABSTRACT

We have developed a high-resolution x-ray spectrometer for measuring the shapes of spectral lines produced from laser-irradiated targets on the Orion laser facility. The instrument utilizes a spherically bent crystal geometry to spatially focus and spectrally analyze photons from foil or microdot targets. The high photon collection efficiency resulting from its imaging properties allows the instrument to be mounted outside the Orion chamber, where it is far less sensitive to particles, hard x-rays, or electromagnetic pulses than instruments housed close to the target chamber center in ten-inch manipulators. Moreover, Bragg angles above 50° are possible, which provide greatly improved spectral resolution compared to radially viewing, near grazing-incidence crystal spectrometers. These properties make the new instrument an ideal lineshape diagnostic for determining plasma temperature and density. We describe its calibration on the Livermore electron beam ion trap facility and present spectral data of the K-shell emission from highly charged sulfur produced by long-pulse as well as short-pulse beams on the Orion laser in the United Kingdom.

9.
Nat Commun ; 6: 6397, 2015 Mar 03.
Article in English | MEDLINE | ID: mdl-25731816

ABSTRACT

The rate at which atoms and ions within a plasma are further ionized by collisions with the free electrons is a fundamental parameter that dictates the dynamics of plasma systems at intermediate and high densities. While collision rates are well known experimentally in a few dilute systems, similar measurements for nonideal plasmas at densities approaching or exceeding those of solids remain elusive. Here we describe a spectroscopic method to study collision rates in solid-density aluminium plasmas created and diagnosed using the Linac Coherent light Source free-electron X-ray laser, tuned to specific interaction pathways around the absorption edges of ionic charge states. We estimate the rate of collisional ionization in solid-density aluminium plasmas at temperatures ~30 eV to be several times higher than that predicted by standard semiempirical models.

11.
Free Radic Res ; 49(2): 175-85, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25426774

ABSTRACT

Chronically haemodialysed end-stage renal disease patients are at high risk of morbidity arising from complications of dialysis, the underlying pathology that has led to renal disease and the complex pathology of chronic kidney disease. Anaemia is commonplace and its origins are multifactorial, involving reduced renal erythropoietin production, accumulation of uremic toxins and an increase in erythrocyte fragility. Oxidative damage is a common risk factor in renal disease and its co-morbidities and is known to cause erythrocyte fragility. Therefore, we have investigated the hypothesis that specific erythrocyte membrane proteins are more oxidised in end-stage renal disease patients and that vitamin C supplementation can ameliorate membrane protein oxidation. Eleven patients and 15 control subjects were recruited to the study. Patients were supplemented with 2 × 500 mg vitamin C per day for 4 weeks. Erythrocyte membrane proteins were prepared pre- and post-vitamin C supplementation for determination of protein oxidation. Total protein carbonyls were reduced by vitamin C supplementation but not by dialysis when investigated by enzyme linked immunosorbent assay. Using a western blot to detect oxidised proteins, one protein band, later identified as containing ankyrin, was found to be oxidised in patients but not controls and was reduced significantly by 60% in all patients after dialysis and by 20% after vitamin C treatment pre-dialysis. Ankyrin oxidation analysis may be useful in a stratified medicines approach as a possible marker to identify requirements for intervention in dialysis patients.


Subject(s)
Ankyrins/chemistry , Ascorbic Acid/therapeutic use , Erythrocyte Membrane/chemistry , Kidney Failure, Chronic/blood , Renal Dialysis , Ankyrins/drug effects , Erythrocyte Membrane/drug effects , Humans , Kidney Failure, Chronic/drug therapy , Kidney Failure, Chronic/therapy , Oxidation-Reduction/drug effects
12.
Arch Virol ; 159(12): 3427-33, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25287129

ABSTRACT

Potato mop-top virus (PMTV; family Virgaviridae) was reported recently in the Pacific Northwestern USA. To better understand the genetic diversity of this virus, the complete genome of an isolate from Washington State (WA), USA, was characterized. Sequence comparisons of the WA isolate with other known sequences revealed that the RNA-Rep-encoded RdRp protein and the RNA-CP-encoded coat protein displayed >99 % amino acid sequence identity to those of two Nordic (RdRp) and several European and North American isolates (CP), respectively. The RNA-TGB-encoded TGB 1 and TGB 3 protein sequences had >99 % amino acid sequence identity to the corresponding proteins of Czech and Danish isolates, whereas the TGB 2 protein is identical to those of Colombian isolates. Phylogenetic analysis of the viral genes of the WA isolate reflected the close relationship between WA and European isolates. RFLP analysis of corresponding DNA of RNA TGB and RNA CP revealed that the WA isolate has the RNA TGB-II and RNA CP-B types, which are prevalent in Europe and other parts of world. This is the first report of the complete genome characterization of PMTV from the Americas.


Subject(s)
Genome, Viral , RNA Viruses/classification , RNA Viruses/genetics , RNA, Viral/genetics , Sequence Analysis, DNA , Solanum tuberosum/virology , Amino Acid Sequence , Cluster Analysis , Molecular Sequence Data , Phylogeny , RNA Viruses/isolation & purification , Sequence Homology, Amino Acid , Viral Proteins/genetics , Washington
13.
Biomater Sci ; 2(11): 1672-1682, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25346848

ABSTRACT

Embryonic stem (ES) cells can be differentiated into many neural cell types that hold great potential as cell replacement therapies following spinal cord injury (SCI). Coupling stem cell transplantation with biomaterial scaffolds can produce a unified combination therapy with several potential advantages including enhanced cell survival, greater transplant retention, reduced scarring, and improved integration at the transplant/host interface. Undesired cell types, however, are commonly present in ES-cell derived cultures due to the limited efficiency of most ES cell induction protocols. Heterogeneous cell populations can confound the interaction between the biomaterial and specific neural populations leading to undesired outcomes. In particular, biomaterials scaffolds may enhance tumor formation by promoting survival and proliferation of undifferentiated ES cells that can persist after induction. Methods for purification of specific ES cell-derived neural populations are necessary to recognize the full potential of combination therapies involving biomaterials and ES cell-derived neural populations. We previously developed a method for enriching ES cell-derived progenitor motor neurons (pMNs) induced from mouse ES cells via antibiotic selection and showed that the enriched cell populations are depleted of pluripotent stem cells. In this study, we demonstrate the survival and differentiation of enriched pMNs within three dimensional (3D) fibrin scaffolds in vitro and when transplanted into a sub-acute dorsal hemisection model of SCI into neurons, oligodendrocytes and astrocytes.

14.
Sci Rep ; 4: 5214, 2014 Jun 09.
Article in English | MEDLINE | ID: mdl-24909903

ABSTRACT

Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

15.
Br Poult Sci ; 55(1): 68-75, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24735472

ABSTRACT

1. Early development of ostrich embryos was investigated in relation to time of egg collection and genotype. 2. A total of 321 ostrich eggs were collected during the 2008 and 2009 breeding seasons and the development of the embryo for up to the first 168 h of incubation was described and analysed. A sample of the incubated eggs was weighed and opened daily to investigate developmental changes. 3. In fresh eggs, the blastoderm contained a round, translucent dark area pellucida (AP) in the centre, with a surrounding thin white ring, likely to be the beginning of the area opaca (AO). Fresh eggs were considered infertile if the blastoderm was absent and instead numerous white droplets were present surrounded by vacuoles. 4. The average blastoderm area of a fresh fertile egg was 15.8 mm(2), increasing to 143.3 mm(2) after 2 d of incubation. By 72 h of incubation the area vasculosa (AV) was discernible in the posterior half of the blastoderm. 5. At 48 h of incubation the blastoderm area in eggs from the South African Black genotype (SAB) × Zimbabwean Blue genotype (ZB) crosses (104.5 ± 18.6 mm(2)) was lower than the pure SAB (141.0 ± 10.5 mm(2)), ZB (161.7 ± 13.5 mm(2)) and ZB × SAB crosses (166.1 ± 14.2 mm(2)). 6. Embryo length was 5.01 mm after 72 h of incubation and 14.5 mm after 168 h of incubation. At 168 h of incubation AV lengths for both ZB × SAB (53.2 mm) and SAB × ZB crosses (54.1 mm) were longer than in embryos from the pure breeds. 7. Results from this study can be put to practical use when determining whether eggs are infertile or fertile and also in investigating the age of early embryonic mortalities.


Subject(s)
Embryo, Nonmammalian/embryology , Embryonic Development , Struthioniformes/embryology , Animal Husbandry , Animals , Struthioniformes/genetics , Time Factors
16.
Phys Rev Lett ; 110(26): 265003, 2013 Jun 28.
Article in English | MEDLINE | ID: mdl-23848885

ABSTRACT

The newly commissioned Orion laser system has been used to study dense plasmas created by a combination of short pulse laser heating and compression by laser driven shocks. Thus the plasma density was systematically varied between 1 and 10 g/cc by using aluminum samples buried in plastic foils or diamond sheets. The aluminum was heated to electron temperatures between 500 and 700 eV allowing the plasma conditions to be diagnosed by K-shell emission spectroscopy. The K-shell spectra show the effect of the ionization potential depression as a function of density. The data are compared to simulated spectra which account for the change in the ionization potential by the commonly used Stewart and Pyatt prescription and an alternative due to Ecker and Kröll suggested by recent x-ray free-electron laser experiments. The experimental data are in closer agreement with simulations using the model of Stewart and Pyatt.

17.
J Orthop Res ; 31(10): 1661-7, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23737292

ABSTRACT

The extracellular matrix (ECM) of the human intervertebral disc is rich in molecules that interact with cells through integrin-mediated attachments. Porcine nucleus pulposus (NP) cells have been shown to interact with laminin (LM) isoforms LM-111 and LM-511 through select integrins that regulate biosynthesis and cell attachment. Since human NP cells lose many phenotypic characteristics with age, attachment and interaction with the ECM may be altered. Expression of LM-binding integrins was quantified for human NP cells using flow cytometry. The cell-ECM attachment mechanism was determined by quantifying cell attachment to LM-111, LM-511, or type II collagen after functionally blocking specific integrin subunits. Human NP cells express integrins ß1, α3, and α5, with over 70% of cells positive for each subunit. Blocking subunit ß1 inhibited NP cell attachment to all substrates. Blocking subunits α1, α2, α3, and α5 simultaneously, but not individually, inhibits NP cell attachment to laminins. While integrin α6ß1 mediated porcine NP cell attachment to LM-111, we found integrins α3, α5, and ß1 instead contributed to human NP cell attachment. These findings identify integrin subunits that may mediate interactions with the ECM for human NP cells and could be used to promote cell attachment, survival, and biosynthesis in cell-based therapeutics.


Subject(s)
Extracellular Matrix Proteins/metabolism , Extracellular Matrix/metabolism , Integrins/metabolism , Intervertebral Disc Displacement/metabolism , Intervertebral Disc/metabolism , Adult , Animals , Flow Cytometry , Humans , Integrin alpha2/metabolism , Integrin alpha3/metabolism , Integrin alpha6beta1/metabolism , Integrin alphaV/metabolism , Integrin beta1/metabolism , Integrin beta3/metabolism , Intervertebral Disc/cytology , Intervertebral Disc Displacement/pathology , Laminin/metabolism , Swine
18.
J Evol Biol ; 26(5): 1129-42, 2013 May.
Article in English | MEDLINE | ID: mdl-23510182

ABSTRACT

The extent to which fluctuating selection can maintain evolutionary stasis in most populations remains an unresolved question in evolutionary biology. Climate has been hypothesized to drive reversals in the direction of selection among different time periods and may also be responsible for intense episodic selection caused by rare weather events. We measured viability selection associated with morphological traits in cliff swallows (Petrochelidon pyrrhonota) in western Nebraska, USA, over a 14-year period following a rare climatic event. We used mark-recapture to estimate the annual apparent survival of over 26 000 individuals whose wing, tail, tarsus and bill had been measured. The fitness functions associated with tarsus length and bill dimensions fluctuated depending on annual climate conditions on the birds' breeding grounds. The oscillating yearly patterns may have slowed and occasionally reversed directional change in trait trajectories, although there was a trend over time for all traits except tarsus to increase in size. The net positive directional selection on some traits, despite periodic climate-associated fluctuations, suggests that cliff swallow morphology in the population is likely to keep changing and supports recent work contending that selection in general does not fluctuate enough to be an effective driver of stasis.


Subject(s)
Climate , Selection, Genetic , Swallows/genetics , Animals , Biological Evolution , Female , Male , Nebraska , Weather
19.
Sci Rep ; 2: 889, 2012.
Article in English | MEDLINE | ID: mdl-23189238

ABSTRACT

Creating non-equilibrium states of matter with highly unequal electron and lattice temperatures (T(ele)≠T(ion)) allows unsurpassed insight into the dynamic coupling between electrons and ions through time-resolved energy relaxation measurements. Recent studies on low-temperature laser-heated graphite suggest a complex energy exchange when compared to other materials. To avoid problems related to surface preparation, crystal quality and poor understanding of the energy deposition and transport mechanisms, we apply a different energy deposition mechanism, via laser-accelerated protons, to isochorically and non-radiatively heat macroscopic graphite samples up to temperatures close to the melting threshold. Using time-resolved x ray diffraction, we show clear evidence of a very small electron-ion energy transfer, yielding approximately three times longer relaxation times than previously reported. This is indicative of the existence of an energy transfer bottleneck in non-equilibrium warm dense matter.

20.
Rev Sci Instrum ; 83(10): 10D732, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23126904

ABSTRACT

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.

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