2,807 research outputs found
Jebel Moya (Sudan): new dates from a mortuary complex at the southern Meroitic frontier
This paper proposes a new chronology for the burial complex at Jebel Moya, south-central Sudan. It reassesses the body of evidence from Sir Henry Wellcome's original 1911–1914 excavations in order to place the site within a firm chronological framework by: (a) applying an attribute-based approach to discern discrete pottery assemblages; and (b) applying initial OSL dates to facilitate the reliable dating of this site for the first time. Jebel Moya is re-interpreted as a burial complex situated on the southern periphery of the late Meroitic state, and its potential to serve as a chronological and cultural reference point for future studies in south-central and southern Sudan is outlined
Determining All Universal Tilers
A universal tiler is a convex polyhedron whose every cross-section tiles the
plane. In this paper, we introduce a certain slight-rotating operation for
cross-sections of pentahedra. Based on a selected initial cross-section and by
applying the slight-rotating operation suitably, we prove that a convex
polyhedron is a universal tiler if and only if it is a tetrahedron or a
triangular prism.Comment: 18 pages, 12 figure
P2Y\u3csub\u3e12\u3c/sub\u3e or P2Y\u3csub\u3e1\u3c/sub\u3e Inhibitors Reduce Platelet Deposition in a Microfluidic Model of Thrombosis while Apyrase Lacks Efficacy Under Flow Conditions
Determination of the patient-specific response to antiplatelet agents facilitates proper dosing for both acute and chronic prophylaxis. Closed systems (with or without flow) may fail to predict pharmacological potency in situations where platelets rapidly accumulate under flow conditions at the site of thrombosis ( Open systems). Using an 8-channel microfluidic flow assay of human whole blood with corn trypsin inhibitor (± PPACK) perfused over focul zones of collagen, dose-response curves were measured for pharmacological agents at a wall shear rate of 210 s-1. The P2Y1 inhibitor MRS 2179 (IC50 = 0.233 ± 0.132 µM) and P2Y12 inhibitor 2-MeSAMP (IC50 = 2.558 ± 0.799 µM) were potent blockers of secondary platelet accumulation under flow, while the P2X1 inhibitor (NF 449) and apyrase failed to reduce platelet accumulation. MRS 2179 and 2-MeSAMP and undetectable effects on initial platelet adhesion to collagen. Numerical simulation of convective-diffusive transport and apyrase-mediated catalytic degradation of ADP indicated that ultra-high concentrations of apyrase (~ 2000 U mL-1) would be required to have the same effect under flow as much lower concentrations (1 U mL-1) currently used in closed systems (aggregometry or cone-and-plate viscometer). This is the first evaluation of IC50 values for P2Y12 and P2Y1 antagonists under controlled flow conditions. Evaluation of antiplatelet agents in open flow systems demonstrates that inhibition of either ADP by apyrase or antagonism of P2X1 signaling had no inhibitory effect on platelet accumulation. This technique provides a platform for rapidly investigating effects of antithrombotic therapies simultaneously in a model injury system
Networked world: Risks and opportunities in the Internet of Things
The Internet of Things (IoT) – devices that are connected to the Internet and collect and use data to operate – is about to transform society. Everything from smart fridges and lightbulbs to remote sensors and cities will collect data that can be analysed and used to provide a wealth of bespoke products and services. The impacts will be huge - by 2020, some 25 billion devices will be connected to the Internet with some studies estimating this number will rise to 125 billion in 2030. These will include many things that have never been connected to the Internet before. Like all new technologies, IoT offers substantial new opportunities which must be considered in parallel with the new risks that come with it. To make sense of this new world, Lloyd’s worked with University College London’s (UCL) Department of Science, Technology, Engineering and Public Policy (STEaPP) and the PETRAS IoT Research Hub to publish this report. ‘Networked world’ analyses IoT’s opportunities, risks and regulatory landscape. It aims to help insurers understand potential exposures across marine, smart homes, water infrastructure and agriculture while highlighting the implications for insurance operations and product development. The report also helps risk managers assess how this technology could impact their businesses and consider how they can mitigate associated risks
Disjoint edges in topological graphs and the tangled-thrackle conjecture
It is shown that for a constant , every simple topological
graph on vertices has edges if it has no two sets of edges such
that every edge in one set is disjoint from all edges of the other set (i.e.,
the complement of the intersection graph of the edges is -free). As an
application, we settle the \emph{tangled-thrackle} conjecture formulated by
Pach, Radoi\v{c}i\'c, and T\'oth: Every -vertex graph drawn in the plane
such that every pair of edges have precisely one point in common, where this
point is either a common endpoint, a crossing, or a point of tangency, has at
most edges
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Cleaning of complex soil layers on vertical walls by fixed and moving impinging liquid jets
Cleaning by a horizontal water jet, impinging onto a soiled Perspex vertical plate, is described. The plate, the substrate, was coated with PVA or petroleum jelly, the soil. The substrate was either.(i) fixed, for batch tests in which the cleaned area, roughly circular, grew with time, or(ii) the substrate moved vertically up or down in its own plane, the water jet remaining fixed; this reproduced the effect of a jet moving across a surface for cleaning, as found in real tank cleaning operations.In the batch experiments, growth of the radius a of the cleaning area is well described, at early times t, by a5 – ao5 = K5 (t – to), ao being the initial radius of the cleaned area at time to; K is a constant. At later times with petroleum jelly, the cleaning front reached a maximum value, when the outward momentum of the radially flowing water film balanced the strength of the soil. This maximum value is modelled as a ramp of viscoplastic soil inclined at angle χ to the substrate surface, where χ was found to vary from 7° to 25°.In the tests of continuous cleaning of petroleum jelly, a lengthening cleaned area, of width wc, was observed on the moving substrate. Near the jet was a stationary clean front, whose shape looked like half an ellipse. This shape, and the width wc, are well described by theory (Wilson et al., 2015, 123, 450–459) using parameters from the above-mentioned batch experiments. This establishes a good link between batch and continuous cleaning experiments.Funding for RKB from the Commonwealth Scholarship Commission is gratefully acknowledged, as are helpful conversations with Michael Smith and Paul Hodgson. FDG measurements on the PVA layers were performed by Shiyao Wang.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jfoodeng.2015.12.02
A statistical analysis of murine incisional and excisional acute wound models
YesMice represent the most commonly used species for preclinical in vivo research. While incisional and excisional acute murine wound models are both frequently employed, there is little agreement on which model is optimum. Moreover, current lack of standardization of wounding procedure, analysis time point(s), method of assessment, and the use of individual wounds vs. individual animals as replicates makes it difficult to compare across studies. Here we have profiled secondary intention healing of incisional and excisional wounds within the same animal, assessing multiple parameters to determine the optimal methodology for future studies. We report that histology provides the least variable assessment of healing. Furthermore, histology alone (not planimetry) is able to detect accelerated healing in a castrated mouse model. Perhaps most importantly, we find virtually no correlation between wounds within the same animal, suggesting that use of wound (not animal) biological replicates is perfectly acceptable. Overall, these findings should guide and refine future studies, increasing the likelihood of detecting novel phenotypes while reducing the numbers of animals required for experimentation
Identification of a system required for the functional surface localization of sugar binding proteins with class III signal peptides in Sulfolobus solfataricus
The hyperthermophilic archaeon Sulfolobus solfataricus contains an unusual large number of sugar binding proteins that are synthesized as precursors with a class III signal peptide. Such signal peptides are commonly used to direct archaeal flagellin subunits or bacterial (pseudo)pilins into extracellular macromolecular surface appendages. Likewise, S. solfataricus binding proteins have been suggested to assemble in higher ordered surface structures as well, tentatively termed the bindosome. Here we show that S. solfataricus contains a specific system that is needed for the functional surface localization of sugar binding proteins. This system, encoded by the bas (bindosome assembly system) operon, is composed of five proteins: basABC, three homologues of so-called bacterial (pseudo)pilins; BasE, a cytoplasmic ATPase; and BasF, an integral membrane protein. Deletion of either the three (pseudo)pilin genes or the basEF genes resulted in a severe defect of the cells to grow on substrates which are transported by sugar binding proteins containing class III signal peptides, while growth on glucose and maltose was restored when the corresponding genes were reintroduced in these cells. Concomitantly, ΔbasABC and ΔbasEF cells were severely impaired in glucose uptake even though the sugar binding proteins were normally secreted across the cytoplasmic membrane. These data underline the hypothesis that the bas operon is involved in the functional localization of sugar binding proteins at the cell surface of S. solfataricus. In contrast to surface structure assembly systems of Gram-negative bacteria, the bas operon seems to resemble an ancestral simplified form of these machineries.
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