XMM-Newton observations of ultraluminous X-ray sources in nearby galaxies

An XMM-Newton study of ultraluminous X-ray sources (ULX) has been performed in a sample of 10 nearby Seyfert galaxies. Eighteen ULX have been found with positional uncertainty of about 4". The large collecting area of XMM-Newton makes the statistics sufficient to perform spectral fitting with simple models in 8 cases. The main results of the present minisurvey strengthen the theory that the ULX could be accreting black holes in hard or soft state. In some cases, the contribution of the ULX to the overall X-ray flux appears to be dominant with respect to that of the active nucleus. In addition, 6 ULX present probable counterparts at other wavelengths (optical/infrared, radio). A multiwavelength observing strategy is required to better assess the nature of these sources.Comment: 10 pages, 11 figures. Accepted for publication by Astronomy and Astrophysics. If you want figures at full resolution, please send an email to Foschin

A survey of current and past Pediatric Infectious Diseases fellows regarding training

<p>Abstract</p> <p>Background</p> <p>The objectives of this study were to characterize the satisfaction of Pediatric Infectious Diseases fellows with their training and to understand how opinions about training have changed over time.</p> <p>Methods</p> <p>Anonymous survey studies were conducted with questions designed to include areas related to the 6 ACGME core competencies. Surveys for current fellows were distributed by fellowship directors, while surveys for graduates were mailed to all individuals with Pediatric Infectious Diseases certification.</p> <p>Results</p> <p>Response rates for current fellows and graduates were 50% and 52%, respectively. Most fellows (98%) and graduates (92%) perceived their overall training favorably. Training in most clinical care areas was rated favorably, however both groups perceived relative deficiencies in several areas. Current fellows rated their training in other competency areas (e.g., systems-based practice, research, and ethics) more favorably when compared to past graduates. Recent graduates perceived their training more favorably in many of these areas compared to past graduates.</p> <p>Conclusions</p> <p>Pediatric Infectious Diseases fellowship training is well regarded by the majority of current and past trainees. Views of current fellows reflect improved satisfaction with training in a variety of competency areas. Persistent deficiencies in clinical training likely reflect active barriers to education. Additional study is warranted to validate perceived deficiencies and to establish consensus on the importance of these areas to infectious diseases training.</p

The reductive activation of CO2 across a Ti═Ti double bond: synthetic, structural, and mechanistic studies

[Image: see text] The reactivity of the bis(pentalene)dititanium double-sandwich compound Ti(2)Pn(†)(2) (1) (Pn(†) = 1,4-{Si(i)Pr(3)}(2)C(8)H(4)) with CO(2) is investigated in detail using spectroscopic, X-ray crystallographic, and computational studies. When the CO(2) reaction is performed at −78 °C, the 1:1 adduct 4 is formed, and low-temperature spectroscopic measurements are consistent with a CO(2) molecule bound symmetrically to the two Ti centers in a μ:η(2),η(2) binding mode, a structure also indicated by theory. Upon warming to room temperature the coordinated CO(2) is quantitatively reduced over a period of minutes to give the bis(oxo)-bridged dimer 2 and the dicarbonyl complex 3. In situ NMR studies indicated that this decomposition proceeds in a stepwise process via monooxo (5) and monocarbonyl (7) double-sandwich complexes, which have been independently synthesized and structurally characterized. 5 is thermally unstable with respect to a μ-O dimer in which the Ti–Ti bond has been cleaved and one pentalene ligand binds in an η(8) fashion to each of the formally Ti(III) centers. The molecular structure of 7 shows a “side-on” bound carbonyl ligand. Bonding of the double-sandwich species Ti(2)Pn(2) (Pn = C(8)H(6)) to other fragments has been investigated by density functional theory calculations and fragment analysis, providing insight into the CO(2) reaction pathway consistent with the experimentally observed intermediates. A key step in the proposed mechanism is disproportionation of a mono(oxo) di-Ti(III) species to yield di-Ti(II) and di-Ti(IV) products. 1 forms a structurally characterized, thermally stable CS(2) adduct 8 that shows symmetrical binding to the Ti(2) unit and supports the formulation of 4. The reaction of 1 with COS forms a thermally unstable complex 9 that undergoes scission to give mono(μ-S) mono(CO) species 10. Ph(3)PS is an effective sulfur transfer agent for 1, enabling the synthesis of mono(μ-S) complex 11 with a double-sandwich structure and bis(μ-S) dimer 12 in which the Ti–Ti bond has been cleaved

Multi-electron reduction of sulfur and carbon disulfide using binuclear uranium(III) borohydride complexes

yesThe first use of a dinuclear UIII/UIII complex in the activation of small molecules is reported. The octadentate Schiff-base pyrrole, anthracene-hinged ‘Pacman’ ligand LA combines two strongly reducing UIII centres and three borohydride ligands in [M(THF)4][{U(BH4)}2(m-BH4)(LA)(THF)2] 1-M, (M ¼ Li, Na, K). The two borohydride ligands bound to uranium outside the macrocyclic cleft are readily substituted by aryloxide ligands, resulting in a single, weakly-bound, encapsulated endo group 1 metal borohydride bridging the two UIII centres in [{U(OAr)}2(m-MBH4)(LA)(THF)2] 2-M (OAr ¼ OC6H2tBu3-2,4,6, M ¼ Na, K). X-ray crystallographic analysis shows that, for 2-K, in addition to the endo-BH4 ligand the potassium countercation is also incorporated into the cleft through h5-interactions with the pyrrolides instead of extraneous donor solvent. As such, 2-K has a significantly higher solubility in non-polar solvents and a wider U–U separation compared to the ‘ate’ complex 1. The cooperative reducing capability of the two UIII centres now enforced by the large and relatively flexible macrocycle is compared for the two complexes, recognising that the borohydrides can provide additional reducing capability, and that the aryloxide-capped 2-K is constrained to reactions within the cleft. The reaction between 1-Na and S8 affords an insoluble, presumably polymeric paramagnetic complex with bridging uranium sulfides, while that with CS2 results in oxidation of each UIII to the notably high UV oxidation state, forming the unusual trithiocarbonate (CS3)2 as a ligand in [{U(CS3)}2(m-k2:k2-CS3)(LA)] (4). The reaction between 2-K and S8 results in quantitative substitution of the endo-KBH4 by a bridging persulfido (S2)2 group and oxidation of each UIII to UIV, yielding [{U(OAr)}2(m-k2:k2-S2)(LA)] (5). The reaction of 2-K with CS2 affords a thermally unstable adduct which is tentatively assigned as containing a carbon disulfido (CS2)2 ligand bridging the two U centres (6a), but only the mono-bridged sulfido (S)2 complex [{U(OAr)}2(m-S (LA)] (6) is isolated. The persulfido complex (5) can also be synthesised from the mono-bridged sulfido complex (6) by the addition of another equivalent of sulfur.EPSRC, European COST networ

A cross-sectional observational study of the nutritional intake of UK primary school children from deprived and non-deprived backgrounds: implications for school breakfast schemes

BACKGROUND: This study examined the nutritional intake of 9-11 year old children in Wales, UK, to assess the rationale for, and potential of, school breakfast initiatives. It also examined the possible unintended consequence of over consumption. METHODS: The study employed a cross-sectional observational design within a randomized controlled trial of a free school breakfast programme. A total of 111 primary schools were randomly assigned to an intervention condition (in which a free school breakfast programme was implemented) or a control condition (in which implementation of the scheme was delayed). Sub-samples of children completed multiple-pass 24-hr dietary recall interviews at baseline (n = 581), and 12 months later (n = 582). Deprivation was assessed for each child in terms of whether or not they were entitled to free school meals. RESULTS: Prior to the introduction of the programme, rates of breakfast skipping were low and there was little evidence of widespread nutritional deficiency. However, there was a subset of children who consumed inadequate levels of a range of vitamins and minerals and 29 % of children ate very little for breakfast (less than 100 kcal). Children that ate larger breakfasts, had higher daily intakes of all nutrients that were examined. Children from deprived backgrounds consumed significantly lower levels of several vitamins and minerals at breakfast. Following the introduction of the breakfast scheme in intervention schools, there was little difference in the nutritional quality of school versus home breakfasts (n = 35 and 211 respectively). Where children ate breakfast at both school and home (n = 33), their overall energy intake was higher, but not significantly so. CONCLUSIONS: Although the overall diet of this group of children was generally good prior to the breakfast scheme, the results suggest that such schemes could be beneficial for a subset of children who are poorly nourished and for those children who consume very little for breakfast. TRIAL REGISTRATION: Current Controlled Trials ISRCTN18336527

Lung diffusing capacity for nitric oxide and carbon monoxide in relation to morphological changes as assessed by computed tomography in patients with cystic fibrosis

Background Due to large-scale destruction, changes in membrane diffusion (Dm) may occur in cystic fibrosis (CF), in correspondence to alterations observed by computed tomography (CT). Dm can be easily quantified via the diffusing capacity for nitric oxide (DLNO), as opposed to the conventional diffusing capacity for carbon monoxide (DLCO). We thus studied the relationship between DLNO as well as DLCO and a CF-specific CT score in patients with stable CF. Methods Simultaneous single-breath determinations of DLNO and DLCO were performed in 21 CF patients (mean ± SD age 35 ± 9 y, FEV1 66 ± 28%pred). Patients also underwent spirometry and bodyplethysmography. CT scans were evaluated via the Brody score and rank correlations (rS) with z-scores of functional measures were computed. Results CT scores correlated best with DLNO (rS = -0.83; p < 0.001). Scores were also related to the volume-specific NO transfer coefficient (KNO; rS = -0.63; p < 0.01) and to DLCO (rS = -0.79; p < 0.001) but not KCO. Z-scores for DLNO were significantly lower than for DLCO (p < 0.001). Correlations with spirometric (e.g., FEV1, IVC) or bodyplethysmographic (e.g., SRaw, RV/TLC) indices were weaker than for DLNO or DLCO but most of them were also significant (p < 0.05 each). Conclusion In this cross sectional study in patients with CF, DLNO and DLCO reflected CT-morphological alterations of the lung better than other measures. Thus the combined diffusing capacity for NO and CO may play a future role for the non-invasive, functional assessment of structural alterations of the lung in CF

Vagal Stimulation Modulates Inflammation through a Ghrelin Mediated Mechanism in Traumatic Brain Injury

Traumatic brain injury (TBI) releases a cascade of inflammatory cytokines. Vagal nerve stimulation (VNS) and ghrelin have known anti-inflammatory effects; furthermore, ghrelin release is stimulated by acetylcholine. We hypothesized VNS decreases post-TBI inflammation through a ghrelin-mediated mechanism. TBI was created in five groups of mice: sham, TBI, TBI/ghrelin, TBI/VNS, and TBI/VNS/ghrelin receptor antagonist (GRa). Serum and tissue ghrelin, and serum TNF-α were measured. Ghrelin increased following VNS 2 h post-TBI compared to sham or TBI. At 6 h, TBI and TBI/VNS/GRa had increased TNF-α compared to sham while TBI/VNS and TBI/ghrelin had TNF-α level comparable to sham. The highest ghrelin was measured in stomach where TBI decreased ghrelin in contrast to an increase by VNS. In conclusion, VNS increased serum ghrelin and decreased TNF-α following TBI. This was abrogated with GRa. Our data suggests that ghrelin plays an important role in the anti-inflammatory effects of VNS following TBI

Chromosome-wide DNA methylation analysis predicts human tissue-specific X inactivation

X-chromosome inactivation (XCI) results in the differential marking of the active and inactive X with epigenetic modifications including DNA methylation. Consistent with the previous studies showing that CpG island-containing promoters of genes subject to XCI are approximately 50% methylated in females and unmethylated in males while genes which escape XCI are unmethylated in both sexes; our chromosome-wide (Methylated DNA ImmunoPrecipitation) and promoter-targeted methylation analyses (Illumina Infinium HumanMethylation27 array) showed the largest methylation difference (D = 0.12, p < 2.2 E−16) between male and female blood at X-linked CpG islands promoters. We used the methylation differences between males and females to predict XCI statuses in blood and found that 81% had the same XCI status as previously determined using expression data. Most genes (83%) showed the same XCI status across tissues (blood, fetal: muscle, kidney and nerual); however, the methylation of a subset of genes predicted different XCI statuses in different tissues. Using previously published expression data the effect of transcription on gene-body methylation was investigated and while X-linked introns of highly expressed genes were more methylated than the introns of lowly expressed genes, exonic methylation did not differ based on expression level. We conclude that the XCI status predicted using methylation of X-linked promoters with CpG islands was usually the same as determined by expression analysis and that 12% of X-linked genes examined show tissue-specific XCI whereby a gene has a different XCI status in at least one of the four tissues examined