Magnesium and silicon in interstellar dust: an X-ray overview

The dense Galactic environment is a large reservoir of interstellar dust. Therefore, this region represents a perfect laboratory to study the properties of the cosmic dust grains. X-rays are the most direct way to detect the interaction of light with dust present in these dense environments. The interaction between the radiation and the interstellar matter imprints specific absorption features in the X-ray spectrum. We study them with the aim of defining the chemical composition, the crystallinity and structure of the dust grains which populate the inner regions of the Galaxy. We investigate the magnesium and the silicon K-edges detected in the Chandra/HETG spectra of eight bright X-ray binaries, distributed in the neighbourhood of the Galactic centre. We model the two spectral features using accurate extinction cross sections of silicates, that we have measured at the synchrotron facility Soleil, France. Near the Galactic centre magnesium and silicon show abundances similar to the solar ones and they are highly depleted from the gas phase ($\delta_{\rm{Mg}}>0.90$ and $\delta_{\rm{Si}}>0.96$). We find that amorphous olivine with a composition of $\rm MgFeSiO_{4}$ is the most representative compound along all lines of sight according to our fits. The contribution of Mg-rich silicates and quartz is low (less than $10\%$). On average we observe a percentage of crystalline dust equal to $11\%$. For the extragalactic source LMC X-1, we find a preference for forsterite, a magnesium-rich olivine. Along this line of sight we also observe an underabundance of silicon $A_{\rm Si}/A_{\rm LMC} = 0.5\pm0.2$.Comment: 16 pages, 7 figures, recommended for publication in Astronomy and Astrophysic

Interstellar oxygen along the line of sight of Cygnus X-2

Interstellar dust permeates our Galaxy and plays an important role in many physical processes in the diffuse and dense regions of the interstellar medium. High-resolution X-ray spectroscopy, coupled with modelling based on laboratory dust measurements, provides a unique probe to investigate the interstellar dust properties along our line of sight towards Galactic X-ray sources. Here, we focus on the oxygen content of the interstellar medium through its absorption features in the X-ray spectra. To model the dust features, we perform a laboratory experiment using the electron microscope facility located at the University of Cadiz in Spain, where we acquire new laboratory data in the oxygen K-edge. We study 18 dust samples of silicates and oxides with different chemical compositions. The laboratory measurements are adopted for our astronomical data analysis. We carry out a case study on the X-ray spectrum of the bright low-mass X-ray binary Cygnus X-2, observed by XMM-Newton. We determine different temperature phases of the ISM, and parameterize oxygen in both gas (neutral and ionised) and dust form. We find Solar abundances of oxygen along the line of sight towards the source. Due to both the relatively low depletion of oxygen into dust form and the shape of the oxygen cross section profiles, it is challenging to determine the precise chemistry of interstellar dust. However, silicates provide an acceptable fit. Finally, we discuss the systematic discrepancies in the atomic (gaseous phase) data of the oxygen edge spectral region using different X-ray atomic databases, and also consider future prospects for studying the ISM with the Arcus concept mission.Comment: Accepted for publication in A&A, 15 pages, 11 figure

Autocrine inhibition of cell motility can drive epithelial branching morphogenesis in the absence of growth

Epithelial branching morphogenesis drives the development of organs such as the lung, salivary gland, kidney and the mammary gland. It involves cell proliferation, cell differentiation and cell migration. An elaborate network of chemical and mechanical signals between the epithelium and the surrounding mesenchymal tissues regulates the formation and growth of branching organs. Surprisingly, when cultured in isolation from mesenchymal tissues, many epithelial tissues retain the ability to exhibit branching morphogenesis even in the absence of proliferation. In this work, we propose a simple, experimentally plausible mechanism that can drive branching morphogenesis in the absence of proliferation and cross-talk with the surrounding mesenchymal tissue. The assumptions of our mathematical model derive from in vitro observations of the behaviour of mammary epithelial cells. These data show that autocrine secretion of the growth factor TGFβ1 inhibits the formation of cell protrusions, leading to curvature-dependent inhibition of sprouting. Our hybrid cellular Potts and partial-differential equation model correctly reproduces the experimentally observed tissue-geometry-dependent determination of the sites of branching, and it suffices for the formation of self-avoiding branching structures in the absence and also in the presence of cell proliferation. This article is part of the theme issue ‘Multi-scale analysis and modelling of collective migration in biological systems’.</p

Incidence of Bladder Cancer in Sri Lanka: Analysis of the Cancer Registry Data and Review of the Incidence of Bladder Cancer in the South Asian Population

PurposeTo investigate the incidence of bladder cancer (BC) in Sri Lanka and to compare risk factors and outcomes with those of other South Asian nations and South Asian migrants to the United Kingdom (UK) and the United States (US).Materials and MethodsThe incidence of BC in Sri Lanka was examined by using two separate cancer registry databases over a 5-year period. Smoking rates were compiled by using a population-based survey from 2001 to 2009 and the relative risk was calculated by using published data.ResultsA total of 637 new cases of BC were diagnosed over the 5-year period. Sri Lankan BC incidence increased from 1985 but remained low (1.36 and 0.3 per 100,000 in males and females) and was similar to the incidence in other South Asian countries. The incidence was lower, however, than in migrant populations in the US and the UK. In densely populated districts of Sri Lanka, these rates almost doubled. Urothelial carcinoma accounted for 72%. The prevalence of male smokers in Sri Lanka was 39%, whereas Pakistan had higher smoking rates with a 6-fold increase in BC.ConclusionsSri Lankan BC incidence was low, similar to other South Asian countries (apart from Pakistan), but the actual incidence is likely higher than the cancer registry rates. Smoking is likely to be the main risk factor for BC. Possible under-reporting in rural areas could account for the low rates of BC in Sri Lanka. Any genetic or environmental protective effects of BC in South Asians seem to be lost on migration to the UK or the US and with higher levels of smoking, as seen in Pakistan

Toenail selenium concentrations and bladder cancer risk in women and men

Prediagnostic selenium concentrations measured in archived toenails were inversely associated with bladder cancer risk in women (P for trend=0.02), but not in men, in a nested case–control study of 338 cases and 341 matched controls. These findings may be due to chance and more studies are needed to determine whether associations between selenium and bladder cancer risk differ by sex

The present and future burden of urinary bladder cancer in the world

Urinary bladder cancer (UBC) is a common disease worldwide. At any point in time 2.7 million people have a history of UBC. The incidence of UBC varies over the world with highest rates in developed communities. But the burden of UBC will increase in less developed areas of the world. These changes can be attributed to global changes in exposure to risk factors for UBC and growth and aging of the world population

Combined proteome and transcriptome analyses for the discovery of urinary biomarkers for urothelial carcinoma

Background: Proteomic discovery of cancer biomarkers in body fluids is challenging because of their low abundance in a complex background. Altered gene expression in tumours may not reflect protein levels in body fluids. We have tested combining gene expression profiling of tumours with proteomic analysis of cancer cell line secretomes as a strategy to discover urinary biomarkers for bladder cancer. Methods: We used shotgun proteomics to identify proteins secreted by three bladder cancer cell lines. Secreted proteins with high mRNA levels in bladder tumours relative to normal urothelium were assayed by ELISA in urine samples from 642 patients. Results: Midkine and HAI-1 were significantly increased in bladder cancer patients, with the highest levels in invasive disease (area under the receiver operating characteristic curve 0.89 vs non-cancer). The urinary concentration of both proteins was too high to be explained by bladder cancer associated haematuria and most likely arises by direct tumour secretion. Conclusions: This ‘dual-omic’ strategy identified tumour secreted proteins whose urine concentrations are increased significantly by bladder cancer. Combined secretome-transcriptome analysis may be more useful than direct proteomic analysis of body fluids for biomarker discovery in both bladder cancer and other tumour type

Enhancement of contact line mobility by means of infrared laser illumination. II. Numerical simulations

A droplet that moves on a solid substrate with a velocity higher than a certain critical velocity disintegrates, i.e., leaves behind residual droplets.Infrared laserillumination can be used to increase the droplet mobility and suppress the shedding of droplets. By means of two-dimensional numerical simulations, we studied the effect of a non-uniform temperature distribution on the dynamics of straight receding contact lines. A streamfunction-vorticity model is used to describe the liquid flow in the vicinity of the receding contact line. The model takes into account the thermocapillary shear stress and the temperature-dependent liquid viscosity and density. A second, coupled model describes the laser-induced displacement of the contact line. Our results show that the reduction of the liquid viscosity with increasing temperature is the dominant mechanism for the increase of the critical velocity. Thermocapillary shear stresses are important primarily for low substrate speeds

The ANKLE TRIAL (ANKLE treatment after injuries of the ankle ligaments): what is the benefit of external support devices in the functional treatment of acute ankle sprain? : a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Acute lateral ankle ligament injuries are very common problems in present health care. Still there is no hard evidence about which treatment strategy is superior. Current evidence supports the view that a functional treatment strategy is preferable, but insufficient data are present to prove the benefit of external support devices in these types of treatment. The hypothesis of our study is that external ankle support devices will not result in better outcome in the treatment of acute ankle sprains, compared to a purely functional treatment strategy. Overall objective is to compare the results of three different strategies of functional treatment for acute ankle sprain, especially to determine the advantages of external support devices in addition to functional treatment strategy, based on balance and coordination exercises.</p> <p>Methods/design</p> <p>This study is designed as a randomised controlled multi-centre trial with one-year follow-up. Adult and healthy patients (N = 180) with acute, single sided and first inversion trauma of the lateral ankle ligaments will be included. They will all follow the same schedule of balancing exercises and will be divided into 3 treatment groups, 1. pressure bandage and tape, 2. pressure bandage and brace and 3. no external support. Primary outcome measure is the Karlsson scoring scale; secondary outcomes are FAOS (subscales), number of recurrent ankle injuries, Visual Analogue Scales of pain and satisfaction and adverse events. They will be measured after one week, 6 weeks, 6 months and 1 year.</p> <p>Discussion</p> <p>The ANKLE TRIAL is a randomized controlled trial in which a purely functional treated control group, without any external support is investigated. Results of this study could lead to other opinions about usefulness of external support devices in the treatment of acute ankle sprain.</p> <p>Trial registration</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2151">NTR2151</a></p