38 research outputs found

    The U.S./Canada Safe Third Country Agreement: A Geographical Evaluation

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    The U.S./Canadian border is in the process of being renegotiated as a result of larger processes of redefining and reimagining sovereign territories inNorth America. New understandings ofU.S.and Canadian state sovereignty are creating a conflated “other” of cross-border flows: an illegitimate migrant figure who is securitized, criminalized and disembodied. The contemporary “othering” of the migrant has serious human rights implications such as the restriction of access to refugee protection. U.S.and Canadian states share an agenda of migration control executed through the manipulation of geography and the figure of the migrant. On paper, the Safe Third Country Agreement (STCA) aims to enhance refugee protection and increase border security. In practice, STCA makes the U.S./Canadian border a battleground for obtaining access to asylum, thus eroding refugee protection inNorth Americaand threatening the security of asylum seekers, theU.S.and Canadian states. In order to evaluate STCA, I conducted field interviews during 2006 and 2007 with persons working in theU.S.and Canadian governments as well as outside the governments in both countries on STCA. Through my analysis of these discussions, official policy documents and relevant literature, I offer three different readings of STCA. This provides a context for STCA and uncovers the motivations for the signing of the policy. The U.S./Canadian STCA functions as an exclusionary measure in a broader field of exclusions: reconfigurations of the border, state sovereignty, territorial limits of the state and the figure of the migrant which aim to reduce the access to and the quality of asylum

    FIB-SEM imaging of carbon nanotubes in mouse lung tissue

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    Ultrastructural characterisation is important for understanding carbon nanotube (CNT) toxicity and how the CNTs interact with cells and tissues. The standard method for this involves using transmission electron microscopy (TEM). However, in particular, the sample preparation, using a microtome to cut thin sample sections for TEM, can be challenging for investigation of regions with agglomerations of large and stiff CNTs because the CNTs cut with difficulty. As a consequence, the sectioning diamond knife may be damaged and the uncut CNTs are left protruding from the embedded block surface excluding them from TEM analysis. To provide an alternative to ultramicrotomy and subsequent TEM imaging, we studied focused ion beam scanning electron microscopy (FIB-SEM) of CNTs in the lungs of mice, and we evaluated the applicability of the method compared to TEM. FIB-SEM can provide serial section volume imaging not easily obtained with TEM, but it is time-consuming to locate CNTs in the tissue. We demonstrate that protruding CNTs after ultramicrotomy can be used to locate the region of interest, and we present FIB-SEM images of CNTs in lung tissue. FIB-SEM imaging was applied to lung tissue from mice which had been intratracheally instilled with two different multiwalled CNTs; one being short and thin, and the other longer and thicker. FIB-SEM was found to be most suitable for detection of the large CNTs (Ø ca. 70 nm), and to be well suited for studying CNT agglomerates in biological samples which is challenging using standard TEM techniques. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-013-7566-x) contains supplementary material, which is available to authorized users

    MWCNTs of different physicochemical properties cause similar inflammatory responses, but differences in transcriptional and histological markers of fibrosis in mouse lungs

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    Multi-walled carbon nanotubes (MWCNTs) are extensively produced and used in composite materials and electronic applications, thus increasing risk of worker and consumer exposure. MWCNTs are an inhomogeneous group of nanomaterials that come in various lengths, shapes and with different metal contaminations, which makes hazard evaluation difficult. However, several studies suggest that length plays an important role in the toxicity induced by MWCNTs. How the length influences toxicity at the molecular level is yet to be characterized. Female C57BL/6 mice were exposed by single intratracheal instillation to 18, 54 or 162 µg/mouse of a short MWCNT (NRCWE-026, 847±102 nm in length) or long MWCNT (NM-401, 4048±366 nm in length). The two MWCNTs were extensively characterized. Lung tissues were harvested 24 h, 3 d and 28 d after exposure. We employed DNA microarrays, bronchoalveolar lavage fluid analysis, comet assay and dichlorodihydrofluorescein assay in order to profile the pulmonary responses. Bioinformatics tools were then applied to compare and contrast the expression profiles and to build a length dependent property-response matrix for gene-by-gene comparison. The toxicogenomic analysis of the global mRNA changes after exposure to the short, entangled NRCWE-026 or the longer, stiffer NM-401 showed high degree of similarities. The toxicity of both MWCNTs was driven by strong inflammatory and acute phase responses, which peaked at day 3 and was observed both in bronchoalveolar lavage cell influx and in gene expression profiles. The inflammatory response was sustained at post-exposure day 28. Also, at the sub-chronic level, we identified a sub-set of 14 fibrosis related genes that were uniquely differentially regulated after exposure to NM-401. Acellular ROS production occurred almost exclusively with NRCWE-026, however the longer NM-401 induced in vivo DNA strand breaks and differential regulation of genes involved in free radical scavenging more readily than NRCWE-026. Our results indicate that the global mRNA response after exposure to MWCNTs is length independent at the acute time points, but that fibrosis may be length dependent sub-chronic end point.JRC.H.6-Digital Earth and Reference Dat

    Time-Dependent Subcellular Distribution and Effects of Carbon Nanotubes in Lungs of Mice

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    BACKGROUND AND METHODS:Pulmonary deposited carbon nanotubes (CNTs) are cleared very slowly from the lung, but there is limited information on how CNTs interact with the lung tissue over time. To address this, three different multiwalled CNTs were intratracheally instilled into female C57BL/6 mice: one short (850 nm) and tangled, and two longer (4 μm and 5.7 μm) and thicker. We assessed the cellular interaction with these CNTs using transmission electron microscopy (TEM) 1, 3 and 28 days after instillation. RESULTS:TEM analysis revealed that the three CNTs followed the same overall progression pattern over time. Initially, CNTs were taken up either by a diffusion mechanism or via endocytosis. Then CNTs were agglomerated in vesicles in macrophages. Lastly, at 28 days post-exposure, evidence suggesting CNT escape from vesicle enclosures were found. The longer and thicker CNTs more often perturbed and escaped vesicular enclosures in macrophages compared to the smaller CNTs. Bronchoalveolar lavage (BAL) showed that the CNT exposure induced both an eosinophil influx and also eosinophilic crystalline pneumonia. CONCLUSION:Two very different types of multiwalled CNTs had very similar pattern of cellular interactions in lung tissue, with the longer and thicker CNTs resulting in more severe effects in terms of eosinophil influx and incidence of eosinophilic crystalline pneumonia (ECP)

    Screening exons 16 and 17 of the amyloid precursor protein gene in sporadic early-onset Alzheimer's disease

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    Early-onset Alzheimer's disease (EOAD) can be familial (FAD) or sporadic EOAD (sEOAD); both have a disease onset ≤65 years of age. A total of 451 sEOAD samples were screened for known causative mutations in exons 16 and 17 of the amyloid precursor protein (APP) gene. Four samples were shown to be heterozygous for 1 of 3 known causative mutations: p.A713T, p.V717I, and p.V717G; this highlights the importance of screening EOAD patients for causative mutations. Additionally, we document an intronic 6 base pair (bp) deletion located 83 bp downstream of exon 17 (rs367709245, IVS17 83-88delAAGTAT), which has a nonsignificantly increased minor allele frequency in our sEOAD cohort (0.006) compared to LOAD (0.002) and controls (0.002). To assess the effect of the 6-bp deletion on splicing, COS-7 and BE(2)-C cells were transfected with a minigene vector encompassing exon 17. There was no change in splicing of exon 17 from constructs containing either wild type or deletion inserts. Sequencing of cDNA generated from cerebellum and temporal cortex of a patient harboring the deletion found no evidence of transcripts with exon 17 remov

    Mutation analysis of sporadic early-onset Alzheimer's disease using the NeuroX array

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    We have screened sporadic early-onset Alzheimer's disease (sEOAD, n = 408) samples using the NeuroX array for known causative and predicted pathogenic variants in 16 genes linked to familial forms of neurodegeneration. We found 2 sEOAD individuals harboring a known causative variant in PARK2 known to cause early-onset Parkinson's disease; p.T240M (n = 1) and p.Q34fs delAG (n = 1). In addition, we identified 3 sEOAD individuals harboring a predicted pathogenic variant in MAPT (p.A469T), which has previously been associated with AD. It is currently unknown if these variants affect susceptibility to sEOAD, further studies would be needed to establish this. This work highlights the need to screen sEOAD individuals for variants that are more classically attributed to other forms of neurodegeneration

    Power Relationships Among Top Managers: Does Top Management Team Power Distribution Matter for Organizational Performance?

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    We investigated patterns of power within top management teams (TMTs) by addressing three research questions: What is the shape of TMT power distribution? Is TMT power distribution associated with firm performance? If so, are there distinguishing TMT characteristics between high and low performers? We evaluate these questions using survey data from top managers in 51 hospitals who identified power relationships among their team members. We find that while the CEO is almost always the most powerful TMT member, no teams in our sample have simply a dominant CEO surrounded by powerless team members. We find that the power inequality within a team is positively associated with firm performance. A TMT is more likely to be associated with strong performance when an executive pair garnered most of the power, and when that pair incorporated different world views, as indicated by differences in functional background and industry experience

    Thromb Haemost

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     Acquired von Willebrand syndrome (AVWS) is frequent in patients with myeloproliferative neoplasms (MPNs). For von Willebrand factor (VWF) functional evaluation, ristocetin cofactor activity by aggregometry (VWF:RCo) is considered the gold standard but has limitations, and automated activity measurement has been developed such as the HemosIL VWF:RCo Werfen with particle agglutination (VWF:GPIbR).  To evaluate the performance of VWF:GPIbR with HemosIL VWF:RCo Werfen (VWF:GPIbR) versus VWF:RCo in patients with thrombocytosis in the context of MPNs (T-MPNs) and in patients with secondary thrombocytosis (ST).  MPN patients with thrombocytosis >450 G/L (T-MPNs) were compared with patients with ST due to inflammation or iron deficiency. VWF activity (VWF:Act) was analyzed using VWF:RCo or VWF:GPIbR. VWF analysis was completed by analysis of VWF multimers and VWF collagen binding (CB) assay (VWF:CB).  A total of 33 T-MPNs and 18 ST patients were included. Compared with aggregometry, evaluation of VWF:Act by VWF:GPIbR led to lower values in T-MPN patients, but also in ST patients. Interestingly, although the VWF:RCo/VWF:Ag ratio did not reveal differences between T-MPNs and ST patients, the VWF:GPIbR/VWF:Ag ratio analysis allowed us to suspect AVWS only in T-MPN patients. Using the distribution of VWF multimer analysis and VWF:CB, we here demonstrated that VWF:GPIbR allows AVWS diagnosis in nine T-MPNs as opposed to aggregometry.  Evaluation of VWF:Act using VWF:GPIbR has a greater sensitivity compared with aggregometry to detect AVWS in T-MPN patients
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