The effect of polypropylene fibres within concrete with regard to fire performance in structures

Purpose – The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires. Design/methodology/approach – Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark following high temperature heat tests to evaluate the surface condition and final compressive strength. A pilot study was used to determine an appropriate heat source for the test. This was three Bunsen burners, however sufficient heat could not be generated within 150mm concrete cubes and the concrete was shown to be a significant insulator and fire protection for structural members. The concrete test cubes were tested in a saturated condition which may reflect conditions where concrete is used in an external environment and thus is subject to soaking. Findings – One hundred and fifty millimetre concrete cubes with and without fibres were placed into a furnace at 1,000°C. Explosive spalling was shown to be reduced with the use of polypropylene fibres but the final compressive strength of concrete was significantly reduced and had little residual structural value after a two hour period of heating. Research limitations/implications – As the concrete tested was saturated, this condition provided a worst case scenario with regards to the build up of hydrostatic and vapour pressure within the cube. A range of percentage moisture contents would produce a more evenly balanced view of the effects of fibres in concrete. A single grade of concrete was used for the test. As the permeability of concrete influences the rate at which steam can escape from the interior of a saturated concrete cube, testing a range of concrete strengths would show this aspect of material performance with regard to spalling and final residual strength. Further research is recommended with regard to moisture contents, strengths of concrete and a range of temperatures

X-ray photoelectron and infrared spectroscopies of quartz samples of contrasting toxicity

An exploratory XPS and FTIR investigation of the surfaces of bulk quartz powders widely used in toxicological studies (DQ12 and Min-U-Sil 5) was carried with the aim of correlating surface features with toxicity as reflected by indicators of biological response. Some patches of amorphous silica were identified as well as varying amounts of calcium but none of these features correlated with biological response. No evidence of widely-quoted surface silanol (SiOH) structures was found in this investigation and the possibility that FTIR artefacts have been previously misidentified as silanol structures is discussed

Biochemical and functional characterization of glycosaminoglycans released from degranulating rat peritoneal mast cells: insights into the physiological role of endogenous heparin

We acknowledge the support of the Wellcome Trust for a grant to RL, CPP and NVR to support some of this work.The properties of commercially prepared heparin as an anticoagulant and antithrombotic agent in medicine are better understood than is the physiological role of heparin in its native form, where it is uniquely found in the secretory granules of mast cells. In the present study we have isolated and characterised the glycosaminoglycans (GAGs) released from degranulating rat peritoneal mast cells. Analysis of the GAGs by NMR spectroscopy showed the presence of both heparin and the galactosaminoglycan dermatan sulphate; heparinase digestion profiles and measurements of anticoagulant activity were consistent with this finding. The rat peritoneal mast cell GAGs significantly inhibited accumulation of leukocytes in the rat peritoneal cavity in response to IL-1β (p < 0.05, n = 6/group), and inhibited adhesion and diapedesis of leukocytes in the inflamed rat cremasteric microcirculation in response to LPS (p < 0.001, n = 4/group). FTIR spectra of human umbilical vein endothelial cells (HUVECs) were altered by treatment of the cells with heparin degrading enzymes, and restored by the addition of exogenous heparin. In conclusion, we have shown that rat peritoneal mast cells contain a mixture of GAGs that possess anticoagulant and anti-inflammatory properties.PostprintPeer reviewe

Structure and reactivity of Cu-doped Au(111) surfaces

The Engineering and Physical Sciences Research Council (EPSRC) is acknowledged for the funding of FG (EP/M029077/1) and RM (EP/506631/1). FG also acknowledges the European Union for funding the SURMOF project under which part of this work was undertaken (contract number NMP4-CT-2006-032109).The structure and surface chemistry of ultrathin metallic films of one metal on another are strongly influenced by factors such as lattice mismatch and the formation of near-surface alloys. New morphologies may result in modified chemical properties which in turn open up different routes for molecular adsorption, desorption and surface functionalization, with important consequences in several fields of application. The Cu/Au(111) system has received the attention of many studies, only a few however have been performed in ultra-high vacuum (UHV), using surface sensitive techniques. In this contribution, the room temperature deposition of copper onto the (22×√3)-Au(111) surface, from submonolayer to thick film, is investigated using scanning tunnelling microscopy (STM). The onset of copper adsorption is seen to occur preferentially at alternate herringbone elbows, with a preference for hcp sites. With increasing coverage, copper-rich islands exhibit a reconstructed surface reminiscent of the clean Au(111) herringbone reconstruction. Disordered, pseudo-ordered and ordered surface layers are observed upon annealing. Models for the initial adsorption/incorporation mechanism, formation of adlayers and evolution with increasing coverage and annealing are qualitatively discussed. Further, the reactivity of copper-doped Au(111) systems is considered towards the adsorption of organic molecules of interest in nanotechnology and their catalytic applications.Publisher PDFPeer reviewe

Evidence of Glycolysis Up-Regulation and Pyruvate Mitochondrial Oxidation Mismatch During Mechanical Unloading of the Failing Human Heart: Implications for Cardiac Reloading and Conditioning

This study sought to investigate the effects of mechanical unloading on myocardial energetics and the metabolic perturbation of heart failure (HF) in an effort to identify potential new therapeutic targets that could enhance the unloading-induced cardiac recovery. The authors prospectively examined paired human myocardial tissue procured from 31 advanced HF patients at left ventricular assist device (LVAD) implant and at heart transplant plus tissue from 11 normal donors. They identified increased post-LVAD glycolytic metabolites without a coordinate increase in early, tricarboxylic acid (TCA) cycle intermediates. The increased pyruvate was not directed toward the mitochondria and the TCA cycle for complete oxidation, but instead, was mainly converted to cytosolic lactate. Increased nucleotide concentrations were present, potentially indicating increased flux through the pentose phosphate pathway. Evaluation of mitochondrial function and structure revealed a lack of post-LVAD improvement in mitochondrial oxidative functional capacity, mitochondrial volume density, and deoxyribonucleic acid content. Finally, post-LVAD unloading, amino acid levels were found to be increased and could represent a compensatory mechanism and an alternative energy source that could fuel the TCA cycle by anaplerosis. In summary, the authors report evidence that LVAD unloading induces glycolysis in concert with pyruvate mitochondrial oxidation mismatch, most likely as a result of persistent mitochondrial dysfunction. These findings suggest that interventions known to improve mitochondrial biogenesis, structure, and function, such as controlled cardiac reloading and conditioning, warrant further investigation to enhance unloading-induced reverse remodeling and cardiac recovery

Strontium isotopic geochemistry of Pan-African/Brasiliano rocks, Chapada copper deposit, Goiás, Brazil

Das Trägergestein der Chapada Kupferlagerstätte in Goiás ist in metamorpher Hoch-Amphibolitfazies ausgebildet. Gesamtgesteins- und individuelle Mineral Rb-Sr-Isochronen mit einem 87 Sr/ 86 Sr-Initialwert (I) von 0,70414±0.00005 ergeben für die Kristallisation der Vulkanite und Magmatite, die die Metamorphose vordatieren, ein Alter von 561±9 Mio Jahre. Die Datierung der Metamorphose während der panafrikanisch/brasilianischen Orogenese (700 bis 450 Mio Jahre) ergibt 532±1 Mio Jahre. Das Mineral-Isochronenalter eines Dioritkörpers porphyrischen Gefüges, der in die Schiefer intrudierte, beträgt 534±16 Mio Jahre (I=0,70415 ±0,00004). Das Ergebnis niedriger Initial-Werte dieser Isochronen ergibt für die Schiefer bei Chapada ein Ausgangs-Material im Bereich des oberen Mantels oder der tieferen Kruste; diese Ausgangswerte sind charakteristisch für magmatische Tätigkeit in Verbindung mit Inselbögen. Das unterkambrische Alter des Trägergesteins bei Chapada steht im Widerspruch zu dem bisher angenommenen mittelproterozoischen Alter und ist ein Hinweis auf eine mögliche Phase intensiverer pan-afrikanisch/brasilianischer magmatischer Aktivität in Zentral-Brasilien als ursprünglich angenommen wurde. Whole rock and mineral Rb-Sr isochrons from the upper amphibolite grade metamorphic host rocks of the Chapada copper deposit in Goiás, Brazil, yield an age of 561±9 Ma, with a 87 Sr/ 86 Sr initial (I) of 0.70414±0.00005, for the crystallization of pre-metamorphic volcanic and igneous rocks and 532 ±1 Ma for their metamorphism during the Pan-African/Brasiliano orogeny (700-450 Ma). A porphyritic diorite stock which intruded the host schists yields a mineral isochron age of 534±16 Ma (I=0.70415±0.00004). The low I values determined from these isochrons suggest that the host schists at Chapada were derived from upper mantle or lower crust material and are characteristic of magmatic products associated with island arcs. The Early Cambrian age of the host rocks at Chapada contradicts the previously assigned mid-Proterozoic age and suggests that Pan-African/Brasiliano magmatic activity may have been more extensive in central Brazil than previously thought. Les roches qui contiennent le gisement de cuivre de Chapada (Goias, Brésil) sont des schistes cristallins appartenent au facies dupérieur des amphibolites. Dans des volcanites et des roches orthomagmatiques appartenant à cet ensemble, des isochrones Rb-Sr sur roches totales et sur minéraux donnent un âge de 561±9 Ma avec un rapport initial de 0,70414±0,00005 pour la cristallisation pré-métamorphique et un âge de 532±1 Ma pour le métamorphisme, lié à l'orogenèse pan-africaine / brésilienne. Un pluton de diorite porphyrique, qui intrude les schistes cristallins donne, par isochrone sur minéraux, un âge de 534±16 Ma (rapport initial de 0,70415±0,00004). Les valeurs basses des rapports initiaux de ces diverses roches suggèrent que les schistes de Chapada sont dérivés de matériaux mantelliques ou crustaux profonds et présentent les caractères des produits magmatiques associés aux arcs insulaires. Leur âge éo-cambrien, en contradiction avec l'âge mésoprotérozoïque admis jusqu'ici, permet de penser que l'activité magmatique pan-africaine/brésilienne dans le centre du Brésil a été plus intense que ce qu'on croyait jusqu'ici. Вмещающие породы зал ежи меди Chapada в Goiбs представляют собой а мфиболитовую фацию в ысшей степени метаморфизм а. Цельная порода и отд ельные минералы дают для кри сталлизации вулкани тов и магматитов до метаморфизма нача льное значение соотн ошения стронция в 0,70414±0,00005, что раз решает принять их возраст в 561± 9 Мио лет, а возраст мет аморфизма в 532±1 Мио, т. е. отнести его к периоду панафриканского -бра зильского орогенеза / 700 до 450 Мио /. При определении в озраста минералов из диоритных тел порфиритовых тек стур, интрудированны х в сланец, получили дат ы в 534±16 Мио лет / 1 = 0,70415 = 0,00004 /. Такое низкое значе ние исходных величин соотношения изотопов разрешает п редполагать, что материал для Chapada при несен был из мантии, или глубинных регион ов коры. Эти исходные з начения характерны для магма тической деятельнос ти типа островных дуг. Во зраст вмещающих поро д считают средне-протерозойск им; это стоит в противо речии с новейшими данными, п о которым он может быт ь только нижнекембрий ским. Это также указыв ает на то, что фаза пан-африка нско-бразильской маг матической активности в централ ьной Бразилии протек ала, возможно, гораздо инт енсивнее, чем принима ли это до сих пор.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47849/1/531_2005_Article_BF01830182.pd

Increasing incidence of invasive pneumococcal disease and pneumonia despite improved vaccination uptake: surveillance in Hull and East Yorkshire, UK, 2002-2009

Introduction of pneumococcal polysaccharide (PPV23) and conjugate vaccine (PCV7) programmes were expected to change the epidemiology of invasive pneumococcal disease (IPD) and pneumonia in the UK. We describe the epidemiology of IPD and hospitalization with pneumonia using high-quality surveillance data over an 8-year period, 2002–2009. Although PPV23 uptake increased from 49% to 70% and PCV7 uptake reached 98% by 2009, the overall incidence of IPD increased from 11·8/100 000 to 16·4/100 000 (P=0·13), and the incidence of hospitalization with pneumonia increased from 143/100 000 to 207/100 000 (P<0·001). Although a reduction in the proportion of IPD caused by PCV7 serotypes was observed, concurrent increases in PPV23 and non-vaccine serotype IPD contributed to an increased IPD burden overall. Marked inequalities in the geographical distribution of disease were observed. Existing vaccination programmes have, so far, not been sufficient to address an increasing burden of pneumococcal disease in our locality

Non-invasive imaging of atherosclerotic plaque macrophage in a rabbit model with F-18 FDG PET: a histopathological correlation

BACKGROUND: Coronary atherosclerosis and its thrombotic complications are the major cause of mortality and morbidity throughout the industrialized world. Thrombosis on disrupted atherosclerotic plaques plays a key role in the onset of acute coronary syndromes. Macrophages density is one of the most critical compositions of plaque in both plaque vulnerability and thrombogenicity upon rupture. It has been shown that macrophages have a high uptake of (18)F-FDG (FDG). We studied the correlation of FDG uptake with histopathological macrophage accumulation in atherosclerotic plaques in a rabbit model. METHODS: Atherosclerosis was induced in rabbits (n = 6) by a combination of atherogenic diet and balloon denudation of the aorta. PET imaging was performed at baseline and 2 months after atherogenic diet and coregistered with magnetic resonance (MR) imaging. Normal (n = 3) rabbits served as controls. FDG uptake by the thoracic aorta was expressed as concentration (μCi/ml) and the ratio of aortic uptake-to-blood radioactivity. FDG uptake and RAM-11 antibody positive areas were analyzed in descending aorta. RESULTS: Atherosclerotic aortas showed significantly higher uptake of FDG than normal aortas. The correlation of aortic FDG uptake with macrophage areas assessed by histopathology was statistically significant although it was not high (r = 0.48, p < 0.0001). When uptake was expressed as the ratio of aortic uptake-to-blood activity, it correlated better (r = 0.80, p < 0.0001) with the macrophage areas, due to the correction for residual blood FDG activity. CONCLUSION: PET FDG activity correlated with macrophage content within aortic atherosclerosis. This imaging approach might serve as a useful non-invasive imaging technique and potentially permit monitoring of relative changes in inflammation within the atherosclerotic lesion