650 research outputs found
Guns and butter? Military expenditure and health spending on the eve of the Arab Spring
We examine the validity of the guns-versus-butter hypothesis in the pre-Arab Spring era. Using panel data from 1995 to 2011âthe eve of the Arab uprisingsâwe find no evidence that increased security needs as measured by the number of domestic terrorist attacks are complemented by increased military spending or more importantly âcrowd outâ government expenditure on key public goods such as health care. This suggests that both expenditure decisions were determined by other considerations at the government level
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Innovative Regulatory and Technical Approaches for the U.S. Army Corp of Engineers' Linde FUSRAP Site Remediation
The U.S. Department of Energy (USDOE) created the Formerly Utilized Sites Remedial Action Program (FUSRAP) in 1974 to identify, investigate, and cleanup or control radiological contamination at sites used by the Manhattan Engineer District (MED) and the Atomic Energy Commission (AEC) from the 1940s through the 1960s. The USDOE had identified 46 sites in the program and finished remediation at 24 of the smaller ones before the end of 1997. With the passage of the Energy and Water Resources Appropriation Act of 1998 the United States Army Corps of Engineers (USACE) was designated by Congress with responsibility to manage and execute the FUSRAP. The Linde Site located in Tonawanda, New York was operated by the MED from 1942-1946 to extract uranium from several high-grade ores. This natural uranium was subsequently enriched in U-235 elsewhere in the United States and ultimately used to produce energy or weapons. Though in the process of reviewing alternative disposal options by 1995, the USDOE had operated FUSRAP with a strategy requiring virtually all materials remediated be disposed of at only one Nuclear Regulatory Commission licensed facility. The change in management of the FUSRAP in 1997 allowed the disposal policy of low levels of radioactively contaminated materials found at the remaining sites to be reexamined. This paper presents some of the innovative regulatory and technical approaches employed at the Linde Site that are resulting in project cost savings while meeting applicable or relevant and appropriate requirements as well as fulfilling commitments made to the local community
Genetically engineered minipigs model the major clinical features of human neurofibromatosis type 1.
Neurofibromatosis Type 1 (NF1) is a genetic disease caused by mutations in Neurofibromin 1 (NF1). NF1 patients present with a variety of clinical manifestations and are predisposed to cancer development. Many NF1 animal models have been developed, yet none display the spectrum of disease seen in patients and the translational impact of these models has been limited. We describe a minipig model that exhibits clinical hallmarks of NF1, including café au lait macules, neurofibromas, and optic pathway glioma. Spontaneous loss of heterozygosity is observed in this model, a phenomenon also described in NF1 patients. Oral administration of a mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor suppresses Ras signaling. To our knowledge, this model provides an unprecedented opportunity to study the complex biology and natural history of NF1 and could prove indispensable for development of imaging methods, biomarkers, and evaluation of safety and efficacy of NF1-targeted therapies
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The polygenic nature of telomere length and the anti-ageing properties of lithium
Telomere length is a promising biomarker for age-related disease and a potential anti-ageing drug target. Here, we study the genetic architecture of telomere length and the repositioning potential of lithium as an anti-ageing medication. LD score regression applied to the largest telomere length genome-wide association study to-date, revealed SNP-chip heritability estimates of 7.29%, with polygenic risk scoring capturing 4.4% of the variance in telomere length in an independent cohort (pâ=â6.17âĂâ10-5). Gene-enrichment analysis identified 13 genes associated with telomere length, with the most significant being the leucine rich repeat gene, LRRC34 (pâ=â3.69âĂâ10-18). In the context of lithium, we confirm that chronic use in a sample of 384 bipolar disorder patients is associated with longer telomeres (pâ=â0.03). As complementary evidence, we studied three orthologs of telomere length regulators in a Caenorhabditis elegans model of lithium-induced extended longevity and found all transcripts to be affected post-treatment (pââ0.05). Consequently, this suggests that lithium may be catalysing the activity of endogenous mechanisms that promote telomere lengthening, whereby its efficacy eventually becomes limited by each individual's inherent telomere maintenance capabilities. Our work indicates a potential use of polygenic risk scoring for the prediction of adult telomere length and consequently lithium's anti-ageing efficacy
Filter exchange imaging with crusher gradient modelling detects increased bloodâbrain barrier water permeability in response to mild lung infection
Bloodâbrain barrier (BBB) dysfunction occurs in many brain diseases, and there is increasing evidence to suggest that it is an early process in dementia which may be exacerbated by peripheral infection. Filter-exchange imaging (FEXI) is an MRI technique for measuring trans-membrane water exchange. FEXI data is typically analysed using the apparent exchange rate (AXR) model, yielding estimates of the AXR. Crusher gradients are commonly used to remove unwanted coherence pathways arising from longitudinal storage pulses during the mixing period. We first demonstrate that when using thin slices, as is needed for imaging the rodent brain, crusher gradients result in underestimation of the AXR. To address this, we propose an extended crusher-compensated exchange rate (CCXR) model to account for diffusion-weighting introduced by the crusher gradients, which is able to recover ground truth values of BBB water exchange (kin) in simulated data. When applied to the rat brain, kin estimates obtained using the CCXR model were 3.10 sâ1 and 3.49 sâ1 compared to AXR estimates of 1.24 sâ1 and 0.49 sâ1 for slice thicknesses of 4.0 mm and 2.5 mm respectively. We then validated our approach using a clinically relevant Streptococcus pneumoniae lung infection. We observed a significant 70â±â10% increase in BBB water exchange in rats during active infection (kinâ=â3.78â±â0.42 sâ1) compared to before infection (kinâ=â2.72â±â0.30 sâ1; pâ=â0.02). The BBB water exchange rate during infection was associated with higher levels of plasma von Willebrand factor (VWF), a marker of acute vascular inflammation. We also observed 42% higher expression of perivascular aquaporin-4 (AQP4) in infected animals compared to non-infected controls, while levels of tight junction proteins remain consistent between groups. In summary, we propose a modelling approach for FEXI data which removes the bias in estimated water-exchange rates associated with the use of crusher gradients. Using this approach, we demonstrate the impact of peripheral infection on BBB water exchange, which appears to be mediated by endothelial dysfunction and associated with an increase in perivascular AQP4
Sports teams as complex adaptive systems: manipulating player numbers shapes behaviours during football small-sided games
Small-sided and conditioned games (SSCGs) in sport have been modelled as complex adaptive systems. Research has shown that the relative space per player (RSP) formulated in SSCGs can impact on emergent tactical behaviours. In this study we adopted a systems orientation to analyse how different RSP values, obtained through manipulations of player numbers, influenced four measures of interpersonal coordination observed during performance in SSCGs. For this purpose we calculated positional data (GPS 15 Hz) from ten U-15 football players performing in three SSCGs varying in player numbers (3v3, 4v4 and 5v5). Key measures of SSCG system behaviours included values of (1) playersâ dispersion, (2) teamsâ separateness, (3) coupling strength and time delays between participantsâ emerging movements, respectively. Results showed that values of participantsâ dispersion increased, but the teamsâ separateness remained identical across treatments. Coupling strength and time delay also showed consistent values across SSCGs. These results exemplified how complex adaptive systems, like football teams, can harness inherent degeneracy to maintain similar team spatialâtemporal relations with opponents through changes in inter-individual coordination modes (i.e., playersâ dispersion). The results imply that different team behaviours might emerge at different ratios of field dimension/player numbers. Therefore, sport pedagogists should carefully evaluate the effects of changing RSP in SSCGs as a way of promoting increased or decreased pressure on players
Actin binding to WH2 domains regulates nuclear import of the multifunctional actin regulator JMY
© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molecular Biology of the Cell 23 (2012): 853-863, doi:10.1091/mbc.E11-12-0992.Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. In response to DNA damage, JMY accumulates in the nucleus and promotes p53-dependent apoptosis. JMY's actin-regulatory activity relies on a cluster of three actin-binding WiskottâAldrich syndrome protein homology 2 (WH2) domains that nucleate filaments directly and also promote nucleation activity of the Arp2/3 complex. In addition to these activities, we find that the WH2 cluster overlaps an atypical, bipartite nuclear localization sequence (NLS) and controls JMY's subcellular localization. Actin monomers bound to the WH2 domains block binding of importins to the NLS and prevent nuclear import of JMY. Mutations that impair actin binding, or cellular perturbations that induce actin filament assembly and decrease the concentration of monomeric actin in the cytoplasm, cause JMY to accumulate in the nucleus. DNA damage induces both cytoplasmic actin polymerization and nuclear import of JMY, and we find that damage-induced nuclear localization of JMY requires both the WH2/NLS region and importin ÎČ. On the basis of our results, we propose that actin assembly regulates nuclear import of JMY in response to DNA damage.This work was supported by grants from the National Institutes
of Health, an American Heart Association Predoctoral Fellowship
(J.B.Z.), the Robert Day Allen Fellowship Fund (J.B.Z.), and a
National Science Foundation Predoctoral Fellowship (B.B.)
Discovery of biphenylacetamide-derived inhibitors of BACE1 using de novo structure-based molecular design
ÎČ-Secretase (BACE1), the enzyme responsible for the first and rate-limiting step in the production of amyloid-ÎČ peptides, is an attractive target for the treatment of Alzheimerâs disease. In this study, we report the application of the de novo fragment-based molecular design program SPROUT to the discovery of a series of nonpeptide BACE1 inhibitors based upon a biphenylacetamide scaffold. The binding affinity of molecules based upon this designed molecular scaffold was increased from an initial BACE1 IC50 of 323 ÎŒM to 27 ÎŒM following the synthesis of a library of optimized ligands whose structures were refined using the recently developed SPROUT-HitOpt software. Although a number of inhibitors were found to exhibit cellular toxicity, one compound in the series was found to have useful BACE1 inhibitory activity in a cellular assay with minimal cellular toxicity. This work demonstrates the power of an in silico fragment-based molecular design approach in the discovery of novel BACE1 inhibitors
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