480 research outputs found
Compactness of Scrap Tyre Rubber Aggregates in Standard Proctor Test
No full textAbstractScrap tyre derived aggregates (TDA) have been used in civil engineering since 1990-ties, mainly in the USA. The material may be used in various forms and sizes – from powder, through granulates, tyre shreds, chips. The TDA applications include: lightweight fills in embankments over soft soils, lightweight backfills behind retaining walls, insulation and drainage layers etc. In most of the works the material needs to be compacted to decrease the void ratio of the aggregate and reduce future settlement. This paper presents a study on compactness of four different fractions of scrap tyre rubber (A: 0.1 – 1mm, B: 0.5 – 2mm, C: 2 – 5mm and D: 10 – 40mm) in the standard Proctor test. The results in the form of dependency of dry and bulk density on water content are compared also with adequate results obtained for a clean uniform medium sand. It turns out that the optimum moisture content can be clearly estimated only in the case of the finest fraction (sample A) and it is equal to about 40%. The variability of dry density is however small – it changes from 0.54 to 0.61g/cm3. Coarser TDAs behave more like self-draining materials – they retain much less water and the maximum moisture content equals to about 18%, 23% and 38% in case of tyre chips (D), 2 – 5mm grains (C) and 0.5 – 2mm grains (B) respectively. The dry densities for samples B, C and D possible to be obtained with standard Proctor energy have been estimated as: 0.61, 0.60 and 0.59g/cm3 respectively
Bibliographical essays,
No full textMemorial volume, containing all of Proctor's bibliographical essays and papers, with a memoir prefixed. Edited by A. W. Pollard."Two hundred copies printed. no. 158 [signed] A. W. P."Robert Proctor [memoir]--Report of Proctor memorial fund.--Accipies woodcut.--On two plates in Sotheby's 'Principia typographica.'--Marcus Reinhard and Johann Grüninger.--Incunabula at Grenoble.--The 'Gutenberg' Bible.--A short view of Berthelet's editions of the statues of Henry VIII.--On two Lyonnese editions of the 'Ars moriendi'.--Ulrich von Ellenbog and the press of S. Ulrich at Augsburg.--The French royal Greek types and the Eton Chrysostom.--The early printers of Köln.--Tracts on early printing: I. List of the founts of type and woodcut devices used by the printers of the southern Netherlands in the fifteenth century. II. A note on Eberhard Frommolt of Basel, printer. III. Additions to Campbell's 'Annales de la typographie neérlandaise au 15e siècle.--Table of supplements to Campbell.--Author-register.--Index.Mode of access: Internet
An investigation into the mechanisms of action of #beta#-lactamase enzymes 1 and 2 from B. cereus 569/H
No full textThe pH dependence of the B-lactamase enzymes I and 2 catalysed hydrolysis of
penicillin and cephalosporin derivatives has been investigated. It was shown that the Blactamase
I catalysed hydrolysis of n-alkyl penicillins of increasing chain length produced
an increase inkcaVKm up to the octyl derivative. Despite this it is believed that the activesite
of the B-lactamase I enzyme does not display a strong recognition for B-lactams
containing a hydrophobic C6 side-chain.
It was found that the pH dependence for the enzyme catalysed hydrolysis of
benzyl penicillin and benzyl cephalosporin did not decline as expected at low pH, but
instead the rate levels off.
The incorporation of a negatively charged group into the phenyl C7 side chain of
cephalosporins resulted in lower activity at pH7 compared to that for benzyl cephalosporin,
but at low pH much higher activity is seen: 2-carboxyphenyl cephalosporin was 10 fold more
reactive at pH3 than at pH7. The B-lactamase I catalysed hydrolysis of phenyl substituted
penicillins containing a negatively charged functional group in the phenyl side chain was
more complex. 2-Carboxyphenyl penicillin shows higher activity at low pH, while the 3,4-
carboxyphenyl penicillin derivatives show a typical 'bell-shaped' profile, but with the pKa I
value shifted up-field. This was further investigated by preparing the cis/trans isomers of 2-
carboxycyclohexyl penicillin and cephalosporin.
It was found that the cis 2-
carboxycyclohexyl penicillin compound displayed high activity at low pH, while the trans
compound did not. Neither of the corresponding cepbalosporin derivatives showed evidence
of higher activity at low pH.
The C3 ester and C3 alcohol of penicillins and the C4 cephalosporin lactone were
synthesised. The penicillin alcohol and the cephalosporin lactone were found to be 'good'
substrates for the B-lactamase I enzyme and produced 'normal' pH-rate profiles.
It was found that with the B-lactamase 2 enzyme hydrolysis of n-alkyl penicillins
proceeded at comparable rates irrespective of the length of the C6 side chain alkyl group,
and that the enzyme hydrolysis rate at pH 7 was minimally affected by substituent changes
in the C6/C7 side chains of penicillin and cephalosporin but the behaviour was more
complex when the negatively charged carboxyphenyl B-lactams were investigated. The
enzyme catalysed hydrolysis was greatly reduced when the C3/4 carboxylate group of the
substrate was converted into an alcohol, ester or lactone, suggesting the importance of this
group in the 13-lactamase2 hydrolysis mechanism.
These results raise important questions about the the existing hypotheses which
attempt to explain the mechanism of action of the B-lactamase I and 2 enzymes
Salivary glands require Aurora Kinase B for regeneration after transient innate immune-mediated injury
No full textSevere, irreversible salivary gland disease and oral dryness is experienced by sufferers of Sjögren's syndrome and those treated with irradiation for head and neck cancer. Therefore, major efforts have been made in the last decade to unravel key molecular signals that can drive salivary gland (SG) regeneration and functional restoration. However, the earliest molecular determinants that accompany SG regeneration remain incompletely defined. The present study examined the initial mitogenic events marking the regenerative response of the murine submandibular gland (SMG), following innate immune-mediated injury. Local intraductal administration of the synthetic double stranded (ds) RNA polyinosinic-polycytidylic acid (poly (I:C)) widely, but transiently, depleted the acinar and progenitor cells, 24 hours post poly (I:C) introduction. While the progenitor and duct cells started to proliferate and expand at 72 hours, the Mist1-positve acinar cells did not re-appear until 96 hours post poly (I:C) injury. The cellular replenishment during regeneration involved significant upregulation of the cell cycle promoter Aurora kinase B (AURKB). AURKB, which is expressed in healthy proliferating and cancerous cells, is a serine/threonine protein kinase, well known to orchestrate key events in cell division and cytokinesis. However, the expression and role of AURKB in regeneration of post mitotic salivary gland cells has not been previously explored. In vivo inhibition of AURKB using the selective inhibitor Barasertib (AZD1152-HQPA) interfered with SMG recovery from the transient, but severe poly (I:C)-mediated injury and cellular depletion. AURKB deficiency during regeneration of the injured tissues: disrupted cell cycle progression, repressed renewal of Mist1-positive acinar cells and prevented recovery of salivary secretion. The knowledge gained in this study may be utilized in the development of therapeutic targets for irreversible salivary gland disease.</p
Statistical method for determining No Effect Concentration (NEC)
No full textProgress Code: completedStatement: Statistical study only on existing datasets.<b>Purpose</b><br/>Showcase a new statistical method for determining no effect concentrations (NEC).This data record has been compiled for a statistical methods study, conducted by Abigael Proctor as part of her PhD research in 2018. The data in this record have been used to showcase a new statistical method for determining no effect concentration (NEC). The study uses the data in this record to compare NEC and LCx estimates for copper in four Antarctic marine invertebrate species. The data associated with this record are a subset of four existing larger datasets: <br/>1. amphipod: AAS_2933_Orchomenella_pinguides_Sensitivity_metals_Davis_2010-11<br/>2. copepod: AAS_4100_Toxicity_Copepods<br/>3. gastropod: AAS_2933_MetaToxicityMarine_JuvenileGastropods_Kingston2007<br/>4. ostracod: AAS_2933_MetalToxicityMarine_BrownOstracods_Kingston2007<br/><br/>Subset details are described in the excel file provided
Regeneration of acinar cells following ligation of rat submandibular gland retraces the embryonic-perinatal pathway of cytodifferentiation
No full textAbstractRat submandibular gland can regenerate following ligation-induced atrophy, eventually recovering its normal morphology and function. Previous studies have suggested that the regeneration process implies both self-proliferation of existing acini and formation of new acinar cells. One hypothesis is that new acinar cells may differentiate from the ductal cells in a similar fashion to the process of cytodifferentiation occurring during submandibular glandular development. In this study atrophy was induced, under recovery anaesthesia, by applying a metal clip on the main duct of the submandibular gland without including the chorda lingual nerve. After 2 weeks the duct was deligated for 3, 5 or 7 days or 8 weeks and the glands collected. Tissue was prepared for immunohistochemstry, biochemical analysis and RNA extraction. The histology of the regenerated glands shows several normal-looking acini, which have regained their glycoprotein content (AB/PAS positive), data also confirmed by biochemical analysis (SDS-PAGE/PAS). Regenerating tissue was characterized by the presence of embryonic-like branched structures ending with AB/PAS positive acinar cells. The proteins SMG-B and PSP are normally expressed in acinar cell precursors during development but only by intercalated ductal cells in the adult stage. In the adult regenerating gland mRNA levels of both SMG-B and PSP were found to be up-regulated compared to ligated glands and SMG-B expression localized to acinar cells whilst the ductal cells were negative. This study of rat submandibular gland regeneration suggests new acinar cells have differentiated from ducts and express markers of acinar cell precursors in a similar manner to the cytodifferentiation process occurring during glandular development
1st Ralph Proctor Lecture of ISSMGE. Railroad performance with special reference to ballast and substructure characteristics.
No full textBallasted rail tracks are widely used throughout the world because they are economical, readily drained, and have sufficient load bearing capacity. Despite these advantages, geotechnical concerns such as ballast degradation, fouling (e.g. coal and subgrade soil), poor drainage of soft subgrade, pumping of clayey subgrade, differential track settlement and track misalignment due to excessive lateral movements exacerbate the cost of track maintenance. Globally, billions of dollars are spent annually on the construction and maintenance of rail tracks. Existing industry design standards are often unable to address these problems because they ignore true cyclic loading patterns, track vibrations, and the onset of plasticity and degradation of track materials. The mechanisms of ballast breakage and deformation, understanding the interface behaviour using geosynthetics, the need for effective track confinement using geocells, time-dependent drainage and filtration properties of track materials require further research to improve existing design guidelines. In view of this, large scale laboratory tests have been carried out using state-of-the-art facilities designed and built at the University of Wollongong and in other proactive rail institutes worldwide in Europe, America, Japan and China. Based on these tests, various factors governing the stress-strain behaviour of ballast, the strength and degradation of ballast, the ability of various geosynthetics and synthetic energy absorbing mats to minimise ballast breakage and track settlement, the effectiveness of subballast as a granular filter and its stabilisation with geocell have been analysed. In Australia, field studies on instrumented tracks at Bulli (near Wollongong), Singleton and Sandgate (near Newcastle), have been carried out to assess the performance of railroad embankments stabilised with geosynthetic grids, rubber mats, and prefabricated vertical drains. This inaugural Ralph Proctor Lecture focuses on the current state of research encompassing deformation and degradation assessment of railroads and the benefits of geo-inclusions, highlighting examples of innovations from theory to practice, predominantly based on the own experience of the Author
The mask of the poet : irony and ethos in selected poems by Daniel Defoe
No full textAlthough Defoe wrote more poetry than Milton did, critical attention to his verse has been slight. Twentieth-century scholars have largely limited attention to verse satires of William III's reign. This dissertation explores verse not previously explicated to help determine Defoe's status as a poet. The Introduction surveys the field of previous scholarship in historical, biographical, and rhetorical aspects of Defoe's poetry. Chapter 1 finds the early Meditations establishing verse forms and dominant themes that will characterize Defoe’s later poetry. Chapter 2 analyzes The Character of the Late Dr, Samuel Annes- Zeyt a man whom Defoe depicts as the model Christian minister. The poem forbids vain grief, extols virtue, and affirms the blessings of Heaven for sincere Christians. Chapter 3 examines The Mock Mourners. A Satyr by Way of Elegy on King Wiltiam. The poem combines elegy for sincere mourners, panegyric for William's virtues, and satiric attack for those who rejoiced at the monarch's death. Chapter 4 concerns Defoe's Elegy on the Author-a mock elegy considering implications of the seven years' silence imposed on his satiric pen by magistrates who condemned the author to Newgate and the pillory. Chapter 5, Reformation of Manners, exposes unjust magistrates, decadent clergy, and profligate members of the nobility, Defoe uses both persuasive and punitive satire in hopes of shaming or challenging his readers into mending their ways. Chapter 6 demonstrates the author's involvement with contemporary historical events. Defoe's four poems celebrating the Duke of Marlborough's victories against the French during 1704-06 praise the hero's military prowess and express hope for equal success in subduing warring political parties at home. Chapter 7 examines Defoe's greatest personal crisis. A Hymn to the Pillory, the author's finest creation in the Pindaric mode, views the ironic inversion of justice that punishes the innocent while failing to deter criminals. Chapter 8 studies Defoe's ironic Hymn to the Mob, The poet traces famous mob scenes recorded in the Bible as analogies for violent Jacobite rabble actions of 1710 and 1715. The motif of madness and the necessity of rational legal restraint characterize the poem. A product of his merchant-class, Presbyterian background, Defoe's poetry shows him both conforming to and emerging beyond the ethos of his peers. His verse features forms, genres, and devices popular in his day, but his astute powers of observation, his facility with a wide variety of rhetorical techniques, and his religiously oriented ironic world view mark Defoe's poetry as uniquely his own.English, Department o
Precipitation of specific proteins by freeze-thawing of human saliva
No full textFrozen saliva samples demonstrate a variable amount of precipitate on thawing depending on the type of secretion [submandibular-sublingual (SML) greater than parotid]. This precipitate has been resuspended using EDTA or removed by centrifugation by some workers and others do not mention it. Yet others collect the salivas into EDTA or centrifuge them before freezing. To determine the adsorption of proteins to hydroxyapatite, prior treatment with EDTA would be disadvantageous. The aim here was to determine if the protein pattern in parotid and SML saliva as demonstrated by sodium dodecyl sulphate gel electrophoresis is affected by the formation of precipitates. Portions of parotid and SML saliva were thawed and treated in the following ways: (a) mixed vigorously with a vortex mixer; (b) centrifuged to remove the precipitate; (c) mixed with EDTA (1 and 5 mmol final concentration for parotid and SML samples, respectively) to resuspend the precipitate. The samples were loaded on to gradient (5-20%) SDS gels and, following electrophoresis, the gels were stained with Coomassie brilliant blue R-250. The protein patterns obtained for (a) and (c) were the same. The centrifuged samples demonstrated loss of a specific band of less than 14 kDa, although this was less obvious in the parotid samples. The SML samples also showed a reduction in other lower molecular-weight proteins. This study demonstrates that precipitates in thawed frozen salivas contain specific proteins and that these samples require careful handling to avoid any alteration in the overall protein composition. (C) 2000 Elsevier Science Ltd.</p
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