4,594 research outputs found
An XMM and Chandra view of massive clusters of galaxies to z=1
The X-ray properties of a sample of high redshift (z>0.6), massive clusters
observed with XMM-Newton and Chandra are described, including two exceptional
systems. One, at z=0.89, has an X-ray temperature of T=11.5 (+1.1, -0.9) keV
(the highest temperature of any cluster known at z>0.6), an estimated mass of
(1.4+/-0.2)x10^15 solar masses and appears relaxed. The other, at z=0.83, has
at least three sub-clumps, probably in the process of merging, and may also
show signs of faint filamentary structure at large radii,observed in X-rays. In
general there is a mix of X-ray morphologies, from those clusters which appear
relaxed and containing little substructure to some highly non-virialized and
probably merging systems. The X-ray gas metallicities and gas mass fractions of
the relaxed systems are similar to those of low redshift clusters of the same
temperature, suggesting that the gas was in place, and containing its metals,
by z=0.8. The evolution of the mass-temperature relation may be consistent with
no evolution or with the ``late formation'' assumption. The effect of point
source contamination in the ROSAT survey from which these clusters were
selected is estimated, and the implications for the ROSAT X-ray luminosity
function discussed.Comment: 9 pages, in Carnegie Observatories Astrophysics Series, Vol. 3:
Clusters of Galaxies: Probes of Cosmological Structure and Galaxy Evolution,
ed. J. S. Mulchaey, A. Dressler, and A. Oemler. See
http://www.ociw.edu/ociw/symposia/series/symposium3/proceedings.html for a
full-resolution versio
Anti-diarrhoeal effects of Garcinia kola (Heckel-Holl) seed methanolic extract and its fractions in animal models
This study investigated the In vitro spasmolytic and In vivo anti-diarrhoeal effects of Garcinia kola seed extract/fractions. Extraction was done by maceration in 70% methanol, serially partitioned in ethyl acetate and n-hexane. Qualitative phytochemical screening was carried out on the crude extract/fractions. The In vitro spasmolytic effect of the extract and fractions at different concentrations (0.5×103, 0.2×103,0.1×103, 0.6×102 mg/ml) were investigated against spontaneous and acetylcholine-induced contractions in isolated rabbit jejunum as well as histamine-induced contractions using isolated guinea pig ileum. The In vivo anti-diarrhoeal effect of the extract was evaluated using three diarrhoeal models: castor oil-induced diarrhoea, charcoal meal gastrointestinal transit time and castor oil-induced enteropooling. In each model, 25 mice were randomly divided into five groups of 5 mice each. Group I served as the untreated control, while group II was a positive control. Groups III-V were administered 125, 250 and 500 mg/kg of the crude methanol extract, respectively. The crude extract, ethyl acetate and aqueous fractions at 0.5×103 mg/ml respectively exhibited 14.4%, 12.9% and 12.2% spasmolytic activities against acetylcholine-induced rabbit jejunum contractions. Histamine-induced guinea pig ileum contractions were inhibited by crude extract (6.2%), ethyl acetate (6.2%), aqueous fraction (7.2%) at 0.6×102 mg/ml. For castor oil-induced diarrhoea, the crude extract at 500 mg/kg produced a significant (p < 0.05) decrease in the diarrhoeal index and faecal weight with a percentage inhibition of 70.4% compared with controls. Similarly, the crude extract (500 mg/kg) significantly (p < 0.05) decreased the charcoal meal gastrointestinal transit time with a percentage inhibition of 33.9% and elicited significant (p < 0.05) intraluminal fluid reduction (9.1%) in castor oil-induced enter pooling test when compared with the untreated group. In conclusion, the anti-motility and anti-secretory activities of the crude extract were attributed to the phytochemical constituents present
Effect of vitamin K2 on postural sway in older people who fall:a randomized controlled trial
OBJECTIVES: Vitamin K is thought to be involved in both bone health and maintenance of neuromuscular function. We tested the effect of vitamin K2 supplementation on postural sway, falls, healthcare costs, and indices of physical function in older people at risk of falls.DESIGN: Parallel-group double-blind randomized placebo-controlled trial.SETTING: Fourteen primary care practices in Scotland, UK.PARTICIPANTS: A total of 95 community-dwelling participants aged 65 and older with at least two falls, or one injurious fall, in the previous year.INTERVENTION: Once/day placebo, 200 μg or 400 μg of oral vitamin K2 for 1 year.MEASUREMENTS: The primary outcome was anteroposterior sway measured using sway plates at 12 months, adjusted for baseline. Secondary outcomes included the Short Physical Performance Battery, Berg Balance Scale, Timed Up & Go Test, quality of life, health and social care costs, falls, and adverse events.RESULTS: Mean participant age was 75 (standard deviation [SD] = 7) years. Overall, 58 of 95 (61%) were female; 77 of 95 (81%) attended the 12-month visit. No significant effect of either vitamin K2 dose was seen on the primary outcome of anteroposterior sway (200 μg vs placebo: -.19 cm [95% confidence interval [CI] -.68 to .30; P = .44]; 400 μg vs placebo: .17 cm [95% CI -.33 to .66; P = .50]; or 400 μg vs 200 μg: .36 cm [95% CI -.11 to .83; P = .14]). Adjusted falls rates were similar in each group. No significant treatment effects were seen for other measures of sway or secondary outcomes. Costs were higher in both vitamin K2 arms than in the placebo arm.CONCLUSION: Oral vitamin K2 supplementation did not improve postural sway or physical function in older people at risk of falls.</p
Crystallization and preliminary X-ray crystallographic analysis of a yedU gene product from Escherichia coli
A yedU gene product with a molecular mass of 31 kDa is a hypothetical protein with no known function. The protein was purified and crystallized at 296 K. X-ray diffraction data have been collected to 2.3 Angstrom using synchrotron radiation. The crystals belong to the primitive orthorhombic system, with unit-cell parameters a = 50.56, b = 63.45, c = 168.02 Angstrom. The asymmetric unit contains two monomers of the protein, with a corresponding V-M of 2.25 Angstrom(3) Da(-1) and a solvent content of 44.84%.open2
Bidirectional signaling of neuregulin-2 mediates formation of GABAergic synapses and maturation of glutamatergic synapses in newborn granule cells of postnatal hippocampus
Expression of neuregulin-2 (NRG2) is intense in a few regions of the adult brain where neurogenesis persists; however, little is understood about its role in developments of newborn neurons. To study the role of NRG2 in synaptogenesis at different developmental stages, newborn granule cells in rat hippocampal slice cultures were labeled with retrovirus encoding tetracycline-inducible microRNA targeting NRG2 and treated with doxycycline (Dox) at the fourth or seventh postinfection day (dpi). The developmental increase of GABAergic postsynaptic currents (GPSCs) was suppressed by the early Dox treatment (4 dpi), but not by late treatment (7 dpi). The late Dox treatment was used to study the effect of NRG2 depletion specific to excitatory synaptogenesis. The Dox effect on EPSCs emerged 4 d after the impairment in dendritic outgrowth became evident (10 dpi). Notably, Dox treatment abolished the developmental increases of AMPA-receptor mediated EPSCs and the AMPA/NMDA ratio, indicating impaired maturation of glutamatergic synapses. In contrast to GPSCs, Dox effects on EPSCs and dendritic growth were independent of ErbB4 and rescued by concurrent overexpression of NRG2 intracellular domain. These results suggest that forward signaling of NRG2 mediates GABAergic synaptogenesis and its reverse signaling contributes to dendritic outgrowth and maturation of glutamatergic synapses.117Ysciescopu
Risk Sources Affecting the Asset Management Decision-Making Process in Manufacturing: A Systematic Review of the Literature
Part 4: Product and Asset Life Cycle Management in Smart Factories of Industry 4.0International audienceAsset Management (AM) is promising for value creation from assets in the long term. A major concern to this end relates with the capabilities to achieve effective AM decision-making at every organisational level, i.e. operational, tactical, and strategical. Therefore, the goal of this research, grounded on a systematic literature review, is to identify which are the main sources of uncertainty that may influence the achievement of AM system related objectives and, as such, should be taken into consideration in a risk-informed decision-making process. Taking the manufacturing sector as a reference, the risk sources addressed by the extant literature are identified and mapped against a reference classification scheme. As a result, the research offers a comprehensive framework where risk sources, affecting the AM decision-making process, are systematically mapped. Information management is found to be the main risk source when making asset-related decisions
Inhibition of Expression in Escherichia coli of a Virulence Regulator MglB of Francisella tularensis Using External Guide Sequence Technology
External guide sequences (EGSs) have successfully been used to inhibit expression of target genes at the post-transcriptional level in both prokaryotes and eukaryotes. We previously reported that EGS accessible and cleavable sites in the target RNAs can rapidly be identified by screening random EGS (rEGS) libraries. Here the method of screening rEGS libraries and a partial RNase T1 digestion assay were used to identify sites accessible to EGSs in the mRNA of a global virulence regulator MglB from Francisella tularensis, a Gram-negative pathogenic bacterium. Specific EGSs were subsequently designed and their activities in terms of the cleavage of mglB mRNA by RNase P were tested in vitro and in vivo. EGS73, EGS148, and EGS155 in both stem and M1 EGS constructs induced mglB mRNA cleavage in vitro. Expression of stem EGS73 and EGS155 in Escherichia coli resulted in significant reduction of the mglB mRNA level coded for the F. tularensis mglB gene inserted in those cells
Impaired decisional impulsivity in pathological videogamers
Abstract
Background
Pathological gaming is an emerging and poorly understood problem. Impulsivity is commonly impaired in disorders of behavioural and substance addiction, hence we sought to systematically investigate the different subtypes of decisional and motor impulsivity in a well-defined pathological gaming cohort.
Methods
Fifty-two pathological gaming subjects and age-, gender- and IQ-matched healthy volunteers were tested on decisional impulsivity (Information Sampling Task testing reflection impulsivity and delay discounting questionnaire testing impulsive choice), and motor impulsivity (Stop Signal Task testing motor response inhibition, and the premature responding task). We used stringent diagnostic criteria highlighting functional impairment.
Results
In the Information Sampling Task, pathological gaming participants sampled less evidence prior to making a decision and scored fewer points compared with healthy volunteers. Gaming severity was also negatively correlated with evidence gathered and positively correlated with sampling error and points acquired. In the delay discounting task, pathological gamers made more impulsive choices, preferring smaller immediate over larger delayed rewards. Pathological gamers made more premature responses related to comorbid nicotine use. Greater number of hours played also correlated with a Motivational Index. Greater frequency of role playing games was associated with impaired motor response inhibition and strategy games with faster Go reaction time.
Conclusions
We show that pathological gaming is associated with impaired decisional impulsivity with negative consequences in task performance. Decisional impulsivity may be a potential target in therapeutic management
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