H_2 emission arises outside photodissociation regions in ultra-luminous infrared galaxies

Ultra-luminous infrared galaxies are among the most luminous objects in the local universe and are thought to be powered by intense star formation. It has been shown that in these objects the rotational spectral lines of molecular hydrogen observed at mid-infrared wavelengths are not affected by dust obscuration, leaving unresolved the source of excitation of this emission. Here I report an analysis of archival Spitzer Space Telescope data on ultra-luminous infrared galaxies and demonstrate that star formation regions are buried inside optically thick clouds of gas and dust, so that dust obscuration affects star-formation indicators but not molecular hydrogen. I thereby establish that the emission of H_2 is not co-spatial with the buried starburst activity and originates outside the obscured regions. This is rather surprising in light of the standard view that H_2 emission is directly associated with star-formation activity. Instead, I propose that H_2 emission in these objects traces shocks in the surrounding material, which are in turn excited by interactions with nearby galaxies, and that powerful large-scale shocks cooling by means of H_2 emission may be much more common than previously thought. In the early universe, a boost in H_2 emission by this process may speed up the cooling of matter as it collapsed to form the first stars and galaxies and would make these first structures more readily observable.Comment: Main text and supplemental information, 21 pages including 6 figures, 2 table

The AIMSS Project – III. The Stellar Populations of Compact Stellar Systems

In recent years, a growing zoo of compact stellar systems (CSSs) have been found whose physical properties (mass, size, velocity dispersion) place them between classical globular clusters (GCs) and true galaxies, leading to debates about their nature. Here we present results using a so far underutilized discriminant, their stellar population properties. Based on new spectroscopy from 8–10m telescopes, we derive ages, metallicities, and [α/Fe] of 29 CSSs. These range from GCs with sizes of merely a few parsec to compact ellipticals (cEs) larger than M32. Together with a literature compilation, this provides a panoramic view of the stellar population characteristics of early-type systems. We find that the CSSs are predominantly more metal rich than typical galaxies at the same stellar mass. At high mass, the cEs depart from the mass–metallicity relation of massive early-type galaxies, which forms a continuous sequence with dwarf galaxies. At lower mass, the metallicity distribution of ultracompact dwarfs (UCDs) changes at a few times 107 M⊙, which roughly coincides with the mass where luminosity function arguments previously suggested the GC population ends. The highest metallicities in CSSs are paralleled only by those of dwarf galaxy nuclei and the central parts of massive early types. These findings can be interpreted as CSSs previously being more massive and undergoing tidal interactions to obtain their current mass and compact size. Such an interpretation is supported by CSSs with direct evidence for tidal stripping, and by an examination of the CSS internal escape velocities

Evaluating the effects of bilingual traffic signs on driver performance and safety

Variable Message Signs (VMS) can provide immediate and relevant information to road users and bilingual VMS can provide great flexibility in countries where a significant proportion of the population speak an alternative language to the majority. The study reported here evaluates the effect of various bilingual VMS configurations on driver behaviour and safety. The aim of the study was to determine whether or not the visual distraction associated with bilingual VMS signs of different configurations (length, complexity) impacted on driving performance. A driving simulator was used to allow full control over the scenarios, road environment and sign configuration and both longitudinal and lateral driver performance was assessed. Drivers were able to read one and two-line monolingual signs and two-line bilingual signs without disruption to their driving behaviour. However, drivers significantly reduced their speed in order to read four-line monolingual and four-line bilingual signs, accompanied by an increase in headway to the vehicle in front. This implies that drivers are possibly reading the irrelevant text on the bilingual sign and various methods for reducing this effect are discussed

Combination of G-CSF and a TLR4 inhibitor reduce inflammation and promote regeneration in a mouse model of ACLF

BACKGROUND & AIMS: Acute-on-chronic liver failure (ACLF) is characterised by high short-term mortality, systemic inflammation, and failure of hepatic regeneration. Its treatment is an unmet medical need. This study was conducted to explore whether combining TAK-242, a Toll-like receptor-4 (TLR4) antagonist, with Granulocyte-Colony Stimulating Factor (G-CSF) targets inflammation whilst enhancing liver regeneration. METHODS: Two mouse models of ACLF were investigated. Chronic liver injury was induced by carbon tetrachloride followed by either lipopolysaccharide (LPS) or galactosamine (GalN) as extrahepatic or hepatic insults, respectively. G-CSF and/or TLR4-antagonist, TAK-242, were administered daily. The treatment duration was 24h and 5d in the LPS model and 48h in the GalN model, respectively. RESULTS: In a LPS-induced ACLF mouse model treatment with G-CSF was associated with a significant mortality of 66% after 48 hours compared with 0% without G-CSF. Addition of TAK-242 to G-CSF abrogated mortality (0%) and significantly reduced liver cell death, macrophage infiltration and inflammation. In the GalN model, both G-CSF and TAK-242, when used individually, reduced liver injury but their combination was significantly more effective. G-CSF treatment, with or without TAK-242, was associated with activation of the pro-regenerative and anti-apoptotic STAT3 pathway. LPS-driven ACLF was characterized by p21 over-expression suggesting hepatic senescence and inhibition of hepatocyte regeneration. While TAK-242 treatment mitigated the effect on senescence, G-CSF, when co-administered with TAK-242, resulted in a significant increase of markers of hepatocyte regeneration. CONCLUSION: TLR4 inhibition with TAK-242 rescued G-CSF-driven cell death, inflammation, enhanced tissue repair, and significantly induced regeneration thus suggesting that the combination of G-CSF and TAK-242 is a novel approach for the treatment of ACLF. LAY SUMMARY: The combinatorial therapy of Granulocyte-Colony Stimulating Factor and TAK-242, a Toll-like Receptor-4 inhibitor, achieves the dual aim of reducing hepatic inflammation and inducing liver regeneration for the treatment of acute-on-chronic liver failure

Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria

The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different, sub-lethal concentrations (chronic exposure). In order to determine the actual carbaryl concentrations in the water LC–MS/MS was used. For analyses of the cyanotoxin concentration in Daphnia’s body enzyme-linked immunosorbent assay (ELISA) was used. Individual daphnids were cultured in a flow-through system under constant light (16 h of light: 8 h of dark), temperature (20°C), and food conditions (Scenedesmus obliquus, 1 mg of C l−1). The results showed that in the treatments with carbaryl egg numbers per female did not differ significantly from controls, but the mortality of newborns increased significantly. Increasing microcystin concentrations significantly delayed maturation, reduced size at first reproduction, number of eggs, and newborns. The interaction between carbaryl and Microcystis was highly significant. Animals matured later and at a smaller size than in controls. The number of eggs per female was reduced as well. Moreover, combined stressors caused frequent premature delivery of offspring with body deformations such as dented carapax or an undeveloped heart. This effect is concluded to be synergistic and could not be predicted from the effects of the single stressors.

The International-Trade Network: Gravity Equations and Topological Properties

This paper begins to explore the determinants of the topological properties of the international - trade network (ITN). We fit bilateral-trade flows using a standard gravity equation to build a "residual" ITN where trade-link weights are depurated from geographical distance, size, border effects, trade agreements, and so on. We then compare the topological properties of the original and residual ITNs. We find that the residual ITN displays, unlike the original one, marked signatures of a complex system, and is characterized by a very different topological architecture. Whereas the original ITN is geographically clustered and organized around a few large-sized hubs, the residual ITN displays many small-sized but trade-oriented countries that, independently of their geographical position, either play the role of local hubs or attract large and rich countries in relatively complex trade-interaction patterns

Management practices for control of ragwort species

The ragwort species common or tansy ragwort (Jacobaea vulgaris, formerly Senecio jacobaea), marsh ragwort (S. aquaticus), Oxford ragwort (S. squalidus) and hoary ragwort (S. erucifolius) are native in Europe, but invaded North America, Australia and New Zealand as weeds. The abundance of ragwort species is increasing in west-and central Europe. Ragwort species contain different groups of secondary plant compounds defending them against generalist herbivores, contributing to their success as weeds. They are mainly known for containing pyrrolizidine alkaloids, which are toxic to grazing cattle and other livestock causing considerable losses to agricultural revenue. Consequently, control of ragwort is obligatory by law in the UK, Ireland and Australia. Commonly used management practices to control ragwort include mechanical removal, grazing, pasture management, biological control and chemical control. In this review the biology of ragwort species is shortly described and the different management practices are discussed

Regulation of p14ARF expression by miR-24: a potential mechanism compromising the p53 response during retinoblastoma development

<p>Abstract</p> <p>Background</p> <p>Most human cancers show inactivation of both pRB- and p53-pathways. While retinoblastomas are initiated by loss of the <it>RB1 </it>tumor suppressor gene, <it>TP53 </it>mutations have not been found. High expression of the p53-antagonist MDM2 in human retinoblastomas may compromise p53 tumor surveillance so that <it>TP53 </it>mutations are not selected for in retinoblastoma tumorigenesis. We previously showed that p14^ARFprotein, which activates p53 by inhibiting MDM2, is low in retinoblastomas despite high mRNA expression.</p> <p>Methods</p> <p>In human fetal retinas, adult retinas, and retinoblastoma cells, we determined endogenous <it>p14^ARF</it>mRNA, ARF protein, and miR-24 expression, while integrity of p53 signalling in WERI-Rb1 cells was tested using an adenovirus vector expressing p14^ARF. To study p14^ARFbiogenesis, retinoblastoma cells were treated with the proteasome inhibitor, MG132, and siRNA against miR-24.</p> <p>Results</p> <p>In human retinoblastoma cell lines, <it>p14^ARF</it>mRNA was disproportionally high relative to the level of p14^ARFprotein expression, suggesting a perturbation of p14^ARFregulation. When p14^ARFwas over-expressed by an adenovirus vector, expression of p53 and downstream targets increased and cell growth was inhibited indicating an intact p14^ARF-p53 axis. To investigate the discrepancy between <it>p14^ARF</it>mRNA and protein in retinoblastoma, we examined p14^ARFbiogenesis. The proteasome inhibitor, MG132, did not cause p14^ARFaccumulation, although p14^ARFnormally is degraded by proteasomes. miR-24, a microRNA that represses p14^ARFexpression, is expressed in retinoblastoma cell lines and correlates with lower protein expression when compared to other cell lines with high <it>p14^ARF</it>mRNA. Transient over-expression of siRNA against miR-24 led to elevated p14^ARFprotein in retinoblastoma cells.</p> <p>Conclusions</p> <p>In retinoblastoma cells where high levels of <it>p14^ARF</it>mRNA are not accompanied by high p14^ARFprotein, we found a correlation between miR-24 expression and low p14^ARFprotein. p14^ARFprotein levels were restored without change in mRNA abundance upon miR-24 inhibition suggesting that miR-24 could functionally repress expression, effectively blocking p53 tumor surveillance. During retinal tumorigenesis, miR-24 may intrinsically compromise the p53 response to <it>RB1 </it>loss.</p

Evidence for the existence of powder sub-populations in micronized materials : Aerodynamic size-fractions of aerosolized powders possess distinct physicochemical properties

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Purpose: To investigate the agglomeration behaviour of the fine ( 12.8 µm) particle fractions of salmeterol xinafoate (SX) and fluticasone propionate (FP) by isolating aerodynamic size fractions and characterising their physicochemical and re-dispersal properties. Methods: Aerodynamic fractionation was conducted using the Next Generation Impactor (NGI). Re-crystallized control particles, unfractionated and fractionated materials were characterized for particle size, morphology, crystallinity and surface energy. Re-dispersal of the particles was assessed using dry dispersion laser diffraction and NGI analysis. Results: Aerosolized SX and FP particles deposited in the NGI as agglomerates of consistent particle/agglomerate morphology. SX particles depositing on Stages 3 and 5 had higher total surface energy than unfractionated SX, with Stage 5 particles showing the greatest surface energy heterogeneity. FP fractions had comparable surface energy distributions and bulk crystallinity but differences in surface chemistry. SX fractions demonstrated higher bulk disorder than unfractionated and re-crystallized particles. Upon aerosolization, the fractions differed in their intrinsic emission and dispersion into a fine particle fraction (< 5.0 µm). Conclusions: Micronized powders consisted of sub-populations of particles displaying distinct physicochemical and powder dispersal properties compared to the unfractionated bulk material. This may have implications for the efficiency of inhaled drug deliveryPeer reviewe

Plasma Zinc But Not the Exchangeable Zinc Pool Size Differs Between Young and Older Korean Women

This study was done to determine the effect of age on zinc metabolism and status among healthy Korean women. Measures of zinc metabolism and status were measured in eight young women (22–24 years) and seven elderly women (66–75 years) consuming a typical Korean diet. Oral and intravenous tracers highly enriched in 67Zn and 70Zn were administered simultaneously. Multiple plasma, 24-h urines, and fecal samples were collected after isotope administration. In the young women, additional plasma were collected to determine zinc kinetics using a seven-compartmental model. Exchangeable Zinc Pool (EZP) was estimated by Miller’s method. Plasma zinc concentrations were higher in older women than younger women (p < 0.05). EZP and urinary zinc tended to be higher in older women than younger women. Fractional and total zinc absorption and endogenous fecal zinc losses did not differ between young and older women. A comparison of the zinc kinetics of the Korean and American women showed no differences in plasma or EZP zinc parameters. However, absorbed zinc and zinc flux to slowly turning over tissues (Q7) were lower in Korean women than that of Americans (p < 0.01) suggesting the total body zinc content of Korean women is lower than that of American women