bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crack‐healing and mechanical behaviour of Al2O3/SiC composites at elevated temperature
Authors: ANDO K. , KIM B.‐S. , CHU M.‐C. , SAITO S. , TAKAHASHI K. 
Published: June 2004

ABSTRACTAlumina/silicon carbide (Al2O3/SiC) composite ceramics with large self‐crack‐healing ability, high strength and high heat‐resistance limit temperature for strength were developed and subjected to three‐point bending. A semicircular surface crack 100 μm in diameter was made on each sample. Crack‐healing behaviour was systematically studied, as functions of crack‐healing temperature and healing time, and the fatigue strengths of the crack‐healed sample at room temperature and 1373 K were investigated. Four main conclusions were drawn from the present study. (1) Al2O3/SiC composite ceramics have the ability to heal after cracking from 1273to 1673 K in air. (2) The heat‐resistance limit temperature for strength of the crack‐healed sample is ≅1573 K, and ≅68% of the samples fractured from outside the crack‐healed zone in the testing‐temperature range 873–1573 K. (3) The crack‐healed sample exhibited very high fatigue limit at room temperature and also 1373 K. (4) The large self‐crack‐healing ability is a desirable technique for the high structural integrity of ceramic component.
Synchrotron diffraction investigation of the distribution and influence of residual stresses in fatigue
Authors: JAMES M. N. , HATTINGH D. G. , HUGHES D. J. , WEI L.‐W. , PATTERSON E. A. , DA FONSECA J. QUINTA 
Published: June 2004

ABSTRACTThis paper presents some results obtained from synchrotron diffraction investigations into two somewhat related areas of interest to the fatigue community. Firstly, the influence of fatigue cycling on the distribution and magnitude of residual strains and stresses and, secondly, the residual strains and stresses engendered around a growing fatigue crack. Its main premise is that modern tools such as automated synchrotron strain scanning offer the potential for more complete insight into the distribution of residual strains and stresses and their influence on fatigue performance. The first part of the work was accomplished using friction‐stir welded (FSW) and metal‐inert gas (MIG) welded specimens. The particular interest in these specimens was obtaining detailed knowledge regarding as‐welded variation in residual stresses between specimens, the location of peak values relative to local microstructure and stress concentrations, and of their modification during fatigue cycling. Such information may indicate a route forward to the selection of welding process parameters for optimised fatigue performance. The second part of the work considered an established fatigue crack in a compact tension (CT) specimen and examined the ability of synchrotron diffraction to characterize the stresses associated with the plastic enclave around a fatigue crack. This work is of interest in the context of better knowledge of crack‐tip shielding by plasticity‐induced closure and its incorporation into life prediction methodologies.
Time dependent effects in fatigue of titanium and nickel alloys
Authors: EVANS W. J. 
Published: June 2004

ABSTRACTThe paper explores fatigue at both low and high temperature where creep and environmental damage interact with the normal cyclic processes of crack development. This is achieved by studying two contrasting material systems: the titanium alloys (Ti685, Ti834, Ti6246) and the nickel alloys (Udimet 720Li). Particular attention is given to both load and strain control fatigue response and crack development at stress concentration features. In each case there is an interesting balance between the beneficial effects of stress relaxation and the damaging effects of creep and environmental factors. On the crack growth side, the relative contributions of creep and environment are highlighted through measurements made in air and vacuum and by varying R value and dwell time. At the same time, any complications due to closure are removed by careful measurement of closure levels for each condition. The inadequacy of linear damage models for combining cyclic and time dependent effects is highlighted.
The adaptive da/dN method: a solution to the problem of processing crack growth data
Authors: VRIES S. BENEDICTUS‐DE , HORN C. H. L. J. TEN , AMENT P. C. H. , BAKKER A. 
Published: June 2004

ABSTRACTThe standard fatigue data‐processing procedure, published in ASTM E647, is not adapted to the use of modern crack length measurement techniques. Because the use of this standard is usually required by journals, the raw data are often reduced to only a few data points. This way valuable information is simply thrown away and mathematical errors are unintentionally made. More importantly, the fact that no satisfactory reduction method exists, has led to destandardization of the processing procedure. Therefore, a new standard processing method is desired. In this paper a new data‐processing method, referred to as the ‘adaptive da/dN method’, is proposed and discussed. This method is suitable for both optical and modern (electrical or automated) measurement techniques as well as modern (computer‐assisted or ‐controlled) processing techniques. The adaptive da/dN method is validated both by data generated with a certain amount of scatter as well as actual experimental data. It shows a more accurate behaviour than the ASTM standards for all data types.
Reforming the Conventions Regarding Parliamentary Scrutiny of Ministerial Actions
Authors: Holland Ian 
Published: June 2004

Parliamentary scrutiny of government ministers is limited by the convention that one house of parliament cannot compel a member of the other house to appear before it. This convention limits the Senate's capacity to examine ministers who are members of the House of Representatives. It has its origins in UK parliamentary practice, and is given alleged legal force in Australia by virtue of section 49 of Australia's constitution. That section effectively says that Australia's current parliamentary powers, privileges and immunities are those of the UK House of Commons in 1901.However analysis of UK practice prior to the twentieth century reveals a surprising picture. Far from protecting members of one house from the other house's inquiries, it would seem that invitations issued by one chamber to a member of the other were never refused, an element of ‘custom and practice’ now conveniently overlooked. Furthermore, the purpose of the powers had nothing to do with protecting ministers. On the contrary, their origins He in a desire to ensure the strength of parliamentary accountability. If modern Australian practice is to be true to historical House of Commons practice, consideration should be given to ensuring that each chamber does have guaranteed access to ministers of the other house.
The Effect of the Reform of Canadian State‐Owned Enterprises on Major Corporate Governance Mechanisms
Authors: Bozec Richard , Zéghal Daniel , Boujenoui Ameur 
Published: June 2004

Corporate governance is nowadays one of the most discussed topics by academics, practitioners and regulators. Most of the discussion is targeted at publicly held corporations. The present research deals with the issue of governance in the public sector and more specifically in state‐owned enterprises (SOEs). We investigate the effect of the reform of Canadian SOEs on the characteristics of boards and board committees.Our results seem to confirm the presence of significant adjustments in board characteristics following two major events in the reform: commercialisation and privatisation. In both cases, boards have on average evolved towards a set of structures and mechanisms that have the potential to improve independence and governance. This study sheds new lights on the process of adjusting corporate governance mechanisms to new strategies and to new environments.
Issues in Higher Education Quality Assurance
Authors: Blackmur Douglas 
Published: June 2004

This article examines a range of policy issues which concern the quality assurance of higher education by regulatory bodies. There is a widespread consensus that the benefits of at least some forms of external quality assurance of higher education exceed the costs. This is probably a matter of faith more than the outcome of a considered analysis, but public policy in several countries has accepted it nevertheless.There are important questions regarding the manner in which such quality assurance should be conducted. Issues to do with self‐regulation, the use of independent ratings agencies, the role of the courts, the establishment of a government agency, and the public funding of private quality assurance bodies all deserve consideration.Process matters become important once structural issues have been decided. These include quality assurance principles, internationalisation and national jurisdiction; the role of a quality assurance system in qualifications' design and development; what precisely is to be ‘quality assured’ in higher education; the standards to be used in quality assurance; linkages between quality assurance and public funding of higher education; compliance costs; and the utility of a National Qualifications Framework (NQF).This article places considerable emphasis on a discussion of the deficiencies of the NQF approach. It argues that the emphasis placed on the development of an NQF in several systems of educational quality assurance is misplaced: an NQF cannot embrace the complexity of contemporary qualifications systems.Claims to the effect that an NQF is a valuable addition to the sources of information available to national and international labour markets must be treated with scepticism. There are logical and practical issues to be considered in this regard. An NQF is arguably likely to mislead labour markets seriously under existing circumstances.
THE COMING OF AGE OF ISLAND STUDIES
Authors: BALDACCHINO GODFREY 
Published: June 2004

ABSTRACT This paper presents insights into the emerging academic field of ‘island studies’, defined as the interdisciplinary study of islands on their own terms. This exposé is undertaken in two ways: conceptually, by means of a critical and judicious review of the literature across a number of disciplines; and analytically in relation to what is probably the most popular scholarly piece of non‐fiction based on an island society written to date –Coming of Age in Samoa by Margaret Mead.
THE BALLAD DANCE OF THE FAEROESE: ISLAND BIOCULTURAL GEOGRAPHY IN AN AGE OF GLOBALISATION
Authors: CLARK ERIC 
Published: June 2004

ABSTRACT Boundary issues are central to globalisation – the expansion and time‐space integration of human societies – and to both biological and cultural diversity. The latter are, in turn, intrinsically related in processes of coevolution that generate change in the patchwork quilt of cultural and natural landscapes. These processes are especially discernible in small island societies. This paper argues that island studies can enhance our understanding of globalisation processes and how these are involved in the displacement of boundaries and the historically unprecedented decline in both biological and cultural diversity.
ISLAND ECOLOGIES AND CARIBBEAN LITERATURES1
Authors: DELOUGHREY ELIZABETH 
Published: June 2004

ABSTRACT This paper examines the ways in which European colonialism positioned tropical island landscapes outside the trajectories of modernity and history by segregating nature from culture, and it explores how contemporary Caribbean authors have complicated this opposition. By tracing the ways in which island colonisation transplanted and hybridised both peoples and plants, I demonstrate how mainstream scholarship in disciplines as diverse as biogeography, anthropology, history, and literature have neglected to engage with the deep history of island landscapes. I draw upon the literary works of Caribbean writers such as Édouard Glissant, Wilson Harris, Jamaica Kincaid and Olive Senior to explore the relationship between landscape and power.
THROUGH A MIST ON THE OCEAN: HUMAN UNDERSTANDING OF ISLAND ENVIRONMENTS
Authors: NUNN PATRICK D. 
Published: June 2004

ABSTRACT Although generally distinct from continental environments, and therefore of interest in their own right, island environments have been generally misunderstood, misinterpreted, and mismanaged. The main reason is that they have been interpreted for management purposes largely by continent‐trained observers. An example of views towards island size is given. It is argued that the pejorative label ‘small’ should no longer be used to characterise islands. The ways in which island environments have been impacted by humans and their commensals is given. Questions of the sustainable development of island environments are also considered, including for whom these should be sustainable, how extraneous threats like sea‐level rise are best incorporated into such plans, and what threats are posed to the rest of the world by mega‐tsunami from certain island environments. Island environments are best managed by persons who understand their distinct character and who are committed to their future.
THE CONTEMPORARY LURE OF THE ISLAND
Authors: PÉRON FRANÇOISE 
Published: June 2004

ABSTRACT Islands have exercised a fascination on the human imagination. Yet today it is possible to identify a positive need for island experience – an island imperative – in whole sectors of society in developed countries. This condition invites the geographer to investigate the nature and fundamental causes of this ‘lure of the island’. In this paper, it is argued that the enhanced impact of islands on the human imagination is not a passing fad: there is rather an essential contribution of, and by, small islands and their inhabitants to the urban and globalised civilisation of our time.
Valproic acid reduces brain damage induced by transient focal cerebral ischemia in rats: potential roles of histone deacetylase inhibition and heat shock protein induction
Authors: Ren Ming , Leng Yan , Jeong MiRa , Leeds Peter R. , Chuang De‐Maw 
Published: June 2004

AbstractGrowing evidence from in vitro studies supports that valproic acid (VPA), an anti‐convulsant and mood‐stabilizing drug, has neuroprotective effects. The present study investigated whether VPA reduces brain damage and improves functional outcome in a transient focal cerebral ischemia model of rats. Subcutaneous injection of VPA (300 mg/kg) immediately after ischemia followed by repeated injections every 12 h, was found to markedly decrease infarct size and reduce ischemia‐induced neurological deficit scores measured at 24 and 48 h after ischemic onset. VPA treatment also suppressed ischemia‐induced neuronal caspase‐3 activation in the cerebral cortex. VPA treatments resulted in a time‐dependent increase in acetylated histone H3 levels in the cortex and striatum of both ipsilateral and contralateral brain hemispheres of middle cerebral artery occlusion (MCAO) rats, as well as in these brain areas of normal, non‐surgical rats, supporting the in vitro finding that VPA is a histone deacetylase (HDAC) inhibitor. Similarly, heat shock protein 70 (HSP70) levels were time‐dependently up‐regulated by VPA in the cortex and striatum of both ipsilateral and contralateral sides of MCAO rats and in these brain areas of normal rats. Altogether, our results demonstrate that VPA is neuroprotective in the cerebral ischemia model and suggest that the protection mechanisms may involve HDAC inhibition and HSP induction.
A non‐peptidyl neurotrophic small molecule for midbrain dopaminergic neurons
Authors: Lin Leu‐Fen H. , Rubin Lee L. , Xu Mei 
Published: June 2004

AbstractA small organic molecule (CUR‐162590) that selectively enhances survival of midbrain dopaminergic neurons was identified by screening small molecule compound libraries. In embryonic midbrain cultures, CUR‐162590 increased dopamine uptake and the number of dopaminergic neurons without altering the number of total neurons or astroglia or the uptake of GABA or serotonin. CUR‐162590 reduced apoptosis of cultured dopaminergic neurons and protected against death induced by toxins such as MPP+. Several synthetic analogs of CUR‐162590 also had similar bioactivities. CUR‐162590 thus represents a new class of neurotrophic small molecules that may have utility in the treatment of Parkinson's disease, which is marked by degeneration of midbrain dopaminergic neurons.
Glycogen synthase kinase 3: a drug target for CNS therapies
Authors: Bhat Ratan V. , Budd Haeberlein Samantha L. , Avila Jesús 
Published: June 2004

AbstractGlycogen synthase kinase3 (GSK3) is emerging as a prominent drug target in the CNS. The most exciting of the possibilities of GSK3 lies within the treatment of Alzheimer's disease (AD) where abnormal increases in GSK3 levels and activity have been associated with neuronal death, paired helical filament tau formation and neurite retraction as well as a decline in cognitive performance. Abnormal activity of GSK3 is also implicated in stroke. Lithium, a widely used drug for affective disorders, inhibits GSK3 at therapeutically relevant concentrations. Thus while the rationale remains testable, pharmaceutical companies are investing in finding a selective inhibitor of GSK3. In the present review, we summarize the properties of GSK3, and discuss the potential for such a therapy in AD, and other CNS disorders.
Could a loss of α‐synuclein function put dopaminergic neurons at risk?
Authors: Perez Ruth G. , Hastings Teresa G. 
Published: June 2004

AbstractThe α‐synuclein gene is implicated in Parkinson's disease, the symptoms of which occur after a marked loss of substantia nigra dopamine neurons. While the function of α‐synuclein is not entirely elucidated, one function appears to be as a normal regulatory protein that can bind to and inhibit tyrosine hydroxylase, the rate‐limiting enzyme in dopamine synthesis. Soluble α‐synuclein levels may be diminished in Parkinson's disease substantia nigra dopamine neurons both by reduced expression and by α‐synuclein aggregation as Lewy bodies and Lewy neurites form. The loss of functional α‐synuclein may then result in dysregulation of tyrosine hydroxylase, dopamine transport and dopamine storage, resulting in excess cytosolic dopamine. Because dopamine and its metabolites are reactive molecules capable of generating highly reactive quinones and reactive oxygen species, a failure to package dopamine into vesicles could cause irreversible damage to cellular macromolecules and contribute to resultant neurotoxicity. This review focuses on how a loss of normal α‐synuclein function may contribute to the dopamine‐related loss of substantia nigra neurons during Parkinson's disease pathogenesis.
Ceramide influences neurite outgrowth and neuroblastoma cell apoptosis regulated by novel protein kinase C isoforms
Authors: Schultz Anna , Larsson Christer 
Published: June 2004

AbstractWe have previously seen that protein kinase C (PKC) ε induces neurite outgrowth and that PKCδ and PKCθ elicit apoptosis in neuroblastoma cells. In this study we investigate the effects of cell‐permeable C2‐ceramide on these events in SK‐N‐BE(2) neuroblastoma cells. C2‐ceramide abolishes neurite formation induced by overexpression of PKCε and, in cells overexpressing PKCδ or PKCθ, ceramide treatment leads to apoptosis. Exposure to C2‐ceramide also suppressed neurite outgrowth induced by retinoic acid, but ceramide did not abrogate neurite induction by treatment with the ROCK inhibitor Y‐27632, demonstrating that C2‐ceramide is not a general inhibitor of neurite outgrowth. The neurite‐suppressing effect occurs independently of cell‐death. Furthermore, C2‐ceramide relocated PKCε and the isolated regulatory domain of PKCε from the cytosol to the perinuclear region. In contrast, neither the localization of PKCδ nor of PKCθ was affected by C2‐ceramide. Taken together, the data indicate that the neurite‐inhibiting effect of C2‐ceramide treatment may be caused by a re‐localization of PKCε and thus identify a functional consequence of ceramide effects on PKCε localization.
Alterations in hippocampal phospholipid profile by prenatal exposure to ethanol
Authors: Wen Zhiming , Kim Hee‐Yong 
Published: June 2004

AbstractIt has been suggested that hippocampus‐related cognitive processes are especially sensitive to ethanol. To provide an insight into the biochemical mechanisms underlying the hippocampus‐related functional deficits associated with prenatal ethanol exposure, we investigated the effects of chronic ethanol exposure on the phospholipid profile in developing rat hippocampi. High‐performance liquid chromatography/electrospray ionization–mass spectrometry analysis revealed that ethanol lowered the levels of total phosphatidylserine (PS) by 15–20% at all ages examined, primarily owing to the reduction in 1‐stearoyl‐2‐docosahexaenoyl‐PS (18:0,22:6n‐3‐PS) species. Ethanol exposure also led to a decrease in phosphatidylcholine (PC) and an increase in phosphatidylethanolamine (PE), but the total phospholipid content was not significantly changed. At the fatty acid level, ethanol exposure significantly decreased the 22:6n‐3 content at postnatal days 0 and 21, with a slight increase in 22:5n‐6, without changing the total fatty acid content significantly. In conclusion, ethanol depleted PS, especially 22:6‐containing species, and PC from hippocampal membranes with concomitant increase in PE. Alteration of the phospholipid profile in the hippocampus resulting from exposure to ethanol during prenatal and developmental stages may have significant implications with respect to the cognitive dysfunction observed in fetal alcohol syndrome.
Brain antioxidant systems in human methamphetamine users
Authors: Moszczynska Anna , Fitzmaurice Paul , Ang Lee , Kalasinsky Kathryn S. , Peretti Frank J. , Aiken Sally S. , Wickham Dennis J. , Sherwin Allan , Nobrega José N. , Forman Henry J. , Kish Stephen J. 
Published: June 2004

AbstractAnimal data suggest that the widely abused psychostimulant methamphetamine can damage brain dopamine neurones by causing dopamine‐dependent oxidative stress; however, the relevance to human methamphetamine users is unclear. We measured levels of key antioxidant defences [reduced (GSH) and oxidized (GSSG) glutathione, six major GSH system enzymes, copper–zinc superoxide dismutase (CuZnSOD), uric acid] that are often altered after exposure to oxidative stress, in autopsied brain of human methamphetamine users and matched controls. Changes in the total (n = 20) methamphetamine group were limited to the dopamine‐rich caudate (the striatal subdivision with the most severe dopamine loss) in which only activity of CuZnSOD (+ 14%) and GSSG levels (+ 58%) were changed. In the six methamphetamine users with severe (− 72 to − 97%) caudate dopamine loss, caudate CuZnSOD activity (+ 20%) and uric acid levels (+ 63%) were increased with a trend for decreased (− 35%) GSH concentration. Our data suggest that brain levels of many antioxidant systems are preserved in methamphetamine users and that GSH depletion, commonly observed during severe oxidative stress, might occur only with severe dopamine loss. Increased CuZnSOD and uric acid might reflect compensatory responses to oxidative stress. Future studies are necessary to establish whether these changes are associated with oxidative brain damage in human methamphetamine users.