1,522 research outputs found
Oxidation behaviour of single crystal nickel-based superalloys: intermediate temperature effects at 450–550°C
No full textThe oxidation behaviour of two single crystal Ni-based superalloys has been investigated at 450°C and 550°C. Isothermal oxidation was carried out for varying times and it was found that exposure resulted in a sub-micrometre thick oxide. The external and internal oxide kinetics were studied via high-resolution image analysis and both showed sub-parabolic growth rates. Thermogravimetric tests indicated that the overall oxidation growth obeys a near quartic power law while parabolic kinetics can describe the transient oxidation period. Characterisation of the resulting oxides was carried out using electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Results from thermodynamic modelling of the oxide formation are also presented to further assess the postulated mechanism of low-temperature oxidation in these Ni-based superalloys.</p
Data supporting: Oxidation behaviour of single crystal nickel based superalloys: Intermediate temperature effects at 450-550oC
No full textThis data supports the following publication: Evangelou A., Soady K.A., Lockyer S., Gao N., Reed P.A.S.(2017), Oxidation behaviour of single crystal nickel based superalloys: Intermediate temperature effects at 450-550oC.
Abstract:
The oxidation behaviour of two commercially available single crystal nickel based superalloys has been investigated at the lower operating temperature range (450-550ºC) of an industrial gas turbine blade. Isothermal oxidation was carried out for varying times up to 640h and the low temperature exposure resulted in a sub-micron thick oxide. The external and internal oxide kinetics were studied via high resolution image analysis and both showed sub-parabolic growth rates. Thermogravimetric tests indicated that the overall oxidation growth obeys a near quartic power law while parabolic kinetics can describe the transient oxidation period. Characterisation of the resulting oxides was carried out using field emission gun scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Results from thermodynamic modelling (Thermo-Calc) of the oxide formation are also presented to further assess the postulated mechanism of low temperature oxidation in these nickel based superalloys.</span
Biomphalaria glabrata transcriptome: cDNA microarray profiling identifies resistant- and susceptible-specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni
No full text© 2008 Lockyer et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background - Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences.
Results - We have developed a 2053 element cDNA microarray for B. glabrata containing clones from ORESTES (Open Reading frame ESTs) libraries, suppression subtractive hybridization (SSH) libraries and clones identified in previous expression studies. Snail haemocyte RNA, extracted from parasite-challenged resistant and susceptible snails, 2 to 24 h post-exposure to S. mansoni, was hybridized to the custom made cDNA microarray and 98 differentially expressed genes or gene clusters were identified, 94 resistant-associated and 4 susceptible-associated. Quantitative PCR analysis verified the cDNA microarray results for representative transcripts. Differentially expressed genes were annotated and clustered using gene ontology (GO) terminology and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis. 61% of the identified differentially expressed genes have no known function including the 4 susceptible strain-specific transcripts. Resistant strain-specific expression of genes implicated in innate immunity of invertebrates was identified, including hydrolytic enzymes such as cathepsin L, a cysteine proteinase involved in lysis of phagocytosed particles; metabolic enzymes such as ornithine decarboxylase, the rate-limiting enzyme in the production of polyamines, important in inflammation and infection processes, as well as scavenging damaging free radicals produced during production of reactive oxygen species; stress response genes such as HSP70; proteins involved in signalling, such as importin 7 and copine 1, cytoplasmic intermediate filament (IF) protein and transcription enzymes such as elongation factor 1α and EF-2.
Conclusion - Production of the first cDNA microarray for profiling gene expression in B. glabrata provides a foundation for expanding our understanding of pathways and genes involved in the snail internal defence system (IDS). We demonstrate resistant strain-specific expression of genes potentially associated with the snail IDS, ranging from signalling and inflammation responses through to lysis of proteinacous products (encapsulated sporocysts or phagocytosed parasite components) and processing/degradation of these targeted products by ubiquitination.The Wellcome Trus
Learning objects and learning designs: an integrated system for reusable, adaptive and shareable learning content
No full textThis paper proposes a system, the Smart Learning Design Framework, designed to support the development of pedagogically sound learning material within an integrated, platform-independent data structure. The system supports sharing, reuse and adaptation of learning material via a metadata-driven philosophy that enables the technicalities of the system to be imperceptible to the author and consumer. The system proposes the use of pedagogically focused metadata to support and guide the author and to adapt and deliver the content to the targeted consumer. A prototype of the proposed system, which provides proof of concept for the novel processes involved, has been developed. The paper describes the Smart Learning Design Framework and places it within the context of alternative learning object models and frameworks to highlight similarities, differences and advantages of the proposed system
The sickest television show ever: paedogeddon and the British Press
No full textThis paper explores the controversy caused by Paedogeddon, a one-off special of the Channel 4 series Brass Eye broadcast on July 26, 2001. Although the program sought to satirize inconsistencies in the way the British media treats and sensationalizes child sex offenders and their crimes (Clark, 2001), it offended many viewers and caused considerable controversy. More than 900 complaints were made to the Independent Television Commission, almost 250 complaints to the Broadcasting Standards Commission, and 2,000 complaints to Channel 4, “officially” making Paedogeddon the most complained-about television program in British television history at that time. This paper examines the nature of the objections to Paedogeddon as played out on the pages of the British national press and contributes to debates about morally acceptable televisio
Bidirectional total synthesis of dimeric brevianamide alkaloids
No full textThe dimeric brevianamides are a unique collection of bioactive, alkaloid dimers that contain a pair of
proline-tryptophan diketopiperazines. Unlike many other dimeric natural products with this moiety, the
dimeric linkage in the brevianamides is located on the proline side of the diketopiperazine. To date, the
biosynthetic origins of these dimeric brevianamides remains a mystery with all attempted biomimetic
syntheses encountering significant hurdles. This thesis details a pragmatic, non-biomimetic synthetic
strategy that resulted in the total synthesis of one of these dimeric brevianamides and key intermediates
that may yet be used in the total synthesis of other related dimeric alkaloids
Latest results from the MARK II at PEP
No full textWe present single photon annihilation results from the MARK II detector at PEP based on approx. 100 pb/sup -1/ of integrated luminosity taken at a center of mass energy ..sqrt..s = 29 GeV. A study of inclusive leptons for momenta greater than or equal to 2 GeV/c yield the average semileptonic branching ratios of bottom (b) and charm (c) quarks and information about the b fragmentation function. A measurement of the bottom hadron lifetime is presented based on a study of the prompt lepton impact parameters. In addition we report on a precise measurement of the tau lifetime and an updated D/sup 0/ lifetime. We also present a search for supersymmetric electrons, weak neutral current couplings from leptons and bottom particles and evidence for K*'s at PEP. 43 references
An Assessment of Contemporary Dining Out Behaviour: The Moderating Factors of Culture and Food Selection within Chinese Full-Service Restaurants in Shanghai, China
No full textShanghai can be described as metropolitan, a gateway, a hub of international traffic and a multi-cultural city. Given these facts, it can be expected that the Shanghai population is comprised of people from not only different regions of China, but also from other countries. It is been asserted by many researchers (e.g. Bojanic and Xu, 2006) that culture affects one’s dining behavior and people are subject to the influence of other cultures. Shanghai, as a place with a population of mixed cultural background, is therefore an ideal research subject for this study. The main purpose of this study is to understand the dining out behaviour of Shanghai residents in Chinese full-service restaurants in Shanghai, China. This study seeks to understand how other cultures have integrated into the Shanghai culture and how that affects the dining habits of Shanghai people. The study proposes that different people are subject to different levels of acculturation. Past research in the hospitality field indicates that the level of acculturation may affect the food practices and preferences of an individual (Sukalakamala and Brittin, 2006; Maamoun et al, 2007; Kremmyda, et al., 2008). However, most studies about acculturation affecting food habits focus on how people adapt themselves when they move overseas (e.g. Chinese people living in the USA). Little attention has been attributed to studying acculturation within the same country, which is important since people may exhibit different behaviour even within the same culture (Chang, 1979). Therefore, it is the intention of this study to contribute to what is a gap in the literature. This study collected 2103 responses from 42 Chinese full-service restaurants in Shanghai. Both qualitative and quantitative research methods were used in this study. The techniques that this study relied on to analyse the data included statistical computer software AMO S (structural equation modelling), CATPAC (artificial neural network software), SPSS 16.0 which was used for frequency analysis, descriptive analysis, independent sample t-test, one way ANOVA, factor analysis and cluster analysis. Results indicate that culture is a strong predictor of Shanghai people’s dining out behaviour, which includes their motives, restaurant choice, food choice and dining evaluation. It is also evident that Shanghai people are showing a growing awareness towards health food
SPECIFIC RECOGNITION OF N-ACETYLNEURAMINIC ACID IN THE G(M2) EPITOPE BY HUMAN G(M2) ACTIVATOR PROTEIN
No full textG(M2) Activator is a low molecular weight protein cofactor that stimulates the enzymatic conversion of G(M2) into G(M3) by human beta-hexosaminidase A and also the conversion of G(M2) into G(A2) by clostridial sialidase (Wu, Y.-Y., Lockyer, J. M., Sugiyama, E., Pavlova, N. V., Li, Y.-T., and Li, S.- C. (1994) J. Biol. Chem. 269, 16276-16283). Among the five known activator proteins for the enzymatic hydrolysis of glycosphingolipids, only G(M2) activator is effective in stimulating the hydrolysis of G(M2). However, the mechanism of action of G(M2) activator is still not well understood, Using a unique disialosylganglioside, GalNAc-G(D1a), as the substrate, we were able to show that in the presence of G(M2) activator, GalNAc-G(D1a) was specifically converted into GalNAc-G(M1a) by clostridial sialidase, while in the presence of saposin B, a nonspecific activator protein, GalNAc-G(D1a) was converted into both GalNAc-G(M1a) and GalNAc-G(M1b). individual products generated from GalNAc-G(D1a) by clostridial sialidase were identified by thin layer chromatography, negative secondary ion mass spectrometry, and immunostaining with a monoclonal IgM that recognizes the G(M2) epitope. Our results clearly show that G(M2) activator recognizes the G(M2) epitope in GalNAc-G(D1a). Thus, G(M2) activator may interact with the trisaccharide structure of the G(M2) epitope and render the GalNAc and NeuAc residues accessible to beta-hexosaminidase A and sialidase, respectively
History, culture, and trade: a dynamic gravity approach
No full textWhat determines trade patterns? Habit persistence in consumer tastes and learning-by-doing in production imply that history and culture are key determinants. Deriving a dynamic gravity equation from a simple model, it is shown that cultural similarity is a product of history, so that trade patterns are a function of bilateral GDP, current trade costs, and the past history of trade costs. Using a trade data set which spans from 1870 to 2000, it is shown that many gravity variables operate via lagged trade, that historical trade shocks matter, and that trade patterns are persistent, even across centuries.Dynamic Gravity Equation, Endogenous Preferences, Habit Persistence, Learning- By-Doing
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