bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of fungal adherence to plasma‐modified polymethylmethacrylate
Authors: Zamperini C. A. , Machado A. L. , Vergani C. E. , Pavarina A. C. , Rangel E. C. , Cruz N. C. 
Published: June 2010

SummaryThere is a propensity for fungal adherence to the polymethylmethacrylate used for making denture bases. Therefore, this study investigated whether surface modifications with plasma treatments would reduce the adherence of Candida albicans to a denture base resin. Samples (n = 180) with smooth and rough surfaces were made and divided into five groups: control – non‐treated; experimental groups – submitted to plasma treatments to obtain surfaces with different hydrophobicities (Ar/50 W; ArO2/70 W; AAt/130 W) or with incorporated fluoride (Ar/SF670 W). Contact angles were measured immediately after treatments and after samples were immersed in water for 48 h. For each group, half the samples were incubated with saliva before the adherence test. The number of adhered C. albicans was evaluated by counting after crystal violet staining. The plasma treatments were effective in modifying the polymethylmethacrylate surface. However, there was a significant alteration in the contact angle measured after immersion in water. No statistically significant difference in the adherence of C. albicans was observed between the experimental and control groups, irrespective of the presence or absence of saliva, and surface roughness.
Patterns of seed longevity and dormancy in obligate seeding legumes of box‐ironbark forests, south‐eastern Australia
Authors: ORSCHEG C. K. , ENRIGHT N. J. 
Published: June 2010

AbstractCurrent fuel loads and distribution suggest that fire events are infrequent and of a low intensity in the regenerated dry sclerophyll forests of the Victorian box‐ironbark ecosystem. However, many box‐ironbark species possess traits consistent with fire‐cued regeneration. It is unclear the degree to which human disturbance may have altered fire regimes in these forests. The infrequent and low‐intensity fire regime suggested by current fuel dynamics may pose a threat to the persistence of fire‐cued species. Obligate seeders such as those of the Fabaceae and Mimosaceae, common in box‐ironbark understoreys, may be particularly vulnerable if inter‐fire intervals exceed seed longevity. This study used seed burial trials to examine seed dormancy and longevity in five legume species to explore their capacity to regenerate under an infrequent, low‐intensity fire regime. All species displayed dormancy and longevity patterns consistent with other south‐east Australian legumes. Before burial, dormancy levels were high for all species (98–100%). After 3 years, storage under in situ and ex situ conditions, dormancy in Pultenaea prostrata remained at pre‐burial levels with virtually no seed becoming non‐dormant. Over time, some Acacia seed became non‐dormant under both in situ and ex situ storage, with the pattern varying among species. Longevity also varied between species. Variation in the dormancy and longevity patterns observed in these obligate seeder legumes suggests two strategies: (i) releasing a portion of soil‐stored seed from dormancy during the inter‐fire period to permit inter‐fire recruitment; and (ii) retaining most soil‐stored seed as dormant during the inter‐fire interval. Both strategies represent potential weaknesses under a long fire interval regime. The first relies on dormancy release translating to successful recruitment and requires ongoing inter‐fire input into the soil seed bank. The second relies on seed longevity exceeding the inter‐fire interval. Whether either is more suitable to coping with long‐term infrequent fire requires long‐term monitoring.
Contagious dispersal of seeds of synchronously fruiting species beneath invasive and native fleshy‐fruited trees
Authors: WHITE EVE , VIVIAN‐SMITH GABRIELLE 
Published: June 2010

AbstractIn subtropical Australia, many native and invasive plant species rely on a shared suite of frugivores, largely birds, for seed dispersal. Many native plants fruit during summer in this region, whereas most invasive plants fruit during winter, thus providing the opportunity for contagious dispersal of seeds beneath synchronously fruiting species. We sampled invasive and native seed rain beneath the canopy of a native summer‐fruiting tree Guioa semiglauca and an invasive winter‐fruiting tree Cinnamomum camphora, in three study sites over the course of a year. In July, during peak fruiting season for C. camphora and other invasive species, seed rain of invasive species was higher beneath C. camphora than G. semiglauca. This was partly due to the invasive tree Ligustrum lucidum, whose seed rain was three times higher beneath C. camphora than beneath the native tree. In February, seed rain of native species was more abundant beneath the canopy of G. semiglauca than beneath C. camphora, despite the fact that C. camphora was also fruiting at this time. This was probably due to the larger fruit crop produced by G. semiglauca at this time of year. Our study provides evidence that the presence of invasive bird‐dispersed plants may facilitate contagious seed dispersal of other invaders, and likewise native species may facilitate seed spread of other native plants.
Thermoelastic stress analysis of fatigue cracks subject to overloads
Authors: PATKI A. S. , PATTERSON E. A. 
Published: June 2010

ABSTRACTIn this study, the effects of plasticity‐induced crack closure and overloads were investigated using thermoelastic stress analysis (TSA) in aluminum alloy 2024. The amplitude of the stress intensity factors were evaluated during crack growth by fitting a Muskhelishvili‐type description of the crack tip stress fields to the TSA data using the multipoint overdeterministic method. A new method to directly measure the extent of the crack tip plastic zone is proposed based on the phase difference between the TSA and forcing signals. The presence of crack tip plasticity was clearly identified and correlated with changes in the stress intensity factor values obtained from the TSA data both during constant amplitude loading as well as single and multiple overloads. Immediately post‐overload the plastic zone increased in size by up to 50% whereas the amplitude of the stress intensity factor and the crack growth rate decreased until the crack grew through the plastic region created by the overload when the pre‐overload value of the crack growth was re‐attained. The experimental data of mode I stress intensity factor, crack growth rate and radius of crack tip plastic zone obtained from thermoelastic data in the region affected by the overload were used to estimate the exponent in the Wheeler crack growth model which was found to be a function of percentage overload and the number of cycles of overload.
Fatigue crack growth and life prediction of a single interference fitted holed plate
Authors: CHAKHERLOU T. N. , MIRZAJANZADEH M. , SAEEDI K. H. 
Published: June 2010

ABSTRACTTo understand the different aspects of fatigue behaviour of complex structural joints it will be much helpful if the effects of different parameters are studied separately. In this article, to study the isolated effect of interference fit on fatigue life a pined hole specimen is investigated. This specimen is a single‐holed plate with an oversized pin which force fitted to the hole. The investigation was carried out both experimentally and numerically. In the experimental part, interference fitted specimens along with open hole specimens were fatigue tested to study the experimental effect of the interference fit. In the numerical part, three‐dimensional finite element (FE) simulations have been performed in order to obtain the created stresses due to interference fit and subsequent applied longitudinal load at the holed plate. The stress distribution obtained from FE simulation around the hole was used to predict crack initiation life using Smith–Watson–Topper method and fatigue crack growth life using the NASGRO equation with applying the AFGROW computer code. The predicted fatigue life obtained from the numerical methods show a good agreement with the experimental fatigue life.
Plasticity induced crack closure in Middle‐Crack Tension specimen: numerical versus experimental
Authors: ANTUNES F.V. , BRANCO R. , COSTA J. D. , RODRIGUES D. M. 
Published: June 2010

ABSTRACTNumerical studies played a major role in the current understanding of plasticity induced crack closure (PICC), however it is well known that the numerical models simplify the reality by considering discrete crack propagations, relatively high fatigue crack growth rates, sharp cracks and that propagation occurs at a well‐defined load. The objective of this paper is to find if despite these limitations, the numerical predictions of PICC are close to the experimental results. Experimental work was developed to obtain crack opening values in 1‐mm‐thick middle‐tension (M(T)) specimens of AA6016‐T4 aluminium alloy. The opening level was determined from remote compliance data captured by a pin microgauge placed at the centre of the specimen. A numerical model was developed and optimized replicating the experimental test in terms of sample geometry, loading parameters, material behaviour and crack opening measurement technique. The adoption, in the numerical analysis, of a remote measurement technique for determining PICC was found to be robust and adequate for mesh refinement studies. A good agreement was found between experimental and numerical results.
Determination of the Gurson–Tvergaard damage model parameters for simulating small punch tests
Authors: CUESTA I. I. , ALEGRE J. M. , LACALLE R. 
Published: June 2010

ABSTRACTThe objective of the final small punch test (SPT) is to determine the fracture properties of materials, such as fracture toughness, when not enough material is available for the conduct of conventional fracture tests. The damage model developed by Gurson, and subsequently modified by Tvergaard and Needleman (GTN), allows for the numerical simulation of the elastic‐plastic behaviour until fracture. This model is based on several constitutive material parameters that must be calibrated if the model is to be properly applied. In this paper, we develop a consistent methodology for the identification of the GTN damage parameters based on the adjustment of the load‐displacement curve obtained in the SPTs. The methodology presented is applicable to simulating other different SPTs with different thicknesses and test temperatures. Also, the three‐dimensional modelling developed will be useful in the future for analysing the possible anisotropy exhibited by some materials. The next step in the simulation will be to determine its validity in other stress fields with different triaxiality ratios, like the one present in CT specimens, the ultimate goal being to allow for the estimation of the material fracture toughness.
Numerical simulation of residual stress relaxation around a cold‐expanded fastener hole under longitudinal cyclic loading using different kinematic hardening models
Authors: CHAKHERLOU T. N. , YAGHOOBI A. 
Published: June 2010

ABSTRACTCold expansion of fastener holes creates compressive residual stresses around the hole. This well‐known technique improves fatigue life by reducing tensile stress around the holes. However, cyclic loading causes these compressive residual stresses to relax, thus reducing their beneficial effect. Estimation of the fatigue life without considering the residual stress relaxation might lead to inaccurate results. In this research, numerical studies were carried out using 2D finite element (FE) models to determine the initial tangential and radial residual stress distributions generated by cold expansion and their relaxation under cyclic loading. To predict the stress relaxation, four nonlinear kinematic hardening models were applied in simulation of stress/strain path. The results obtained from the FE analysis were compared with available experimental results. A good agreement between the numerical and experimental results was observed.
Structural integrity and damage type in military aircraft
Authors: CLARK G. , JACKSON P. 
Published: June 2010

ABSTRACTThis paper discusses the nature of the damage which can cause unanticipated, early fleet failures in legacy military aircraft. This damage often takes a form quite unlike the notional cracking which is used in structural integrity design, but can lead to high costs, or reduced fleet availability, by requiring additional costly inspections and recovery programs in response to discovery of the damage. Using examples from Australian fleets the paper demonstrates that a lack of diagnostic and prognostic tools contributed to the impact of the damage on the fleet. Development of even simple prognostic and diagnostic tools could reduce the fleet impact and cost of discovered damage, and would ultimately allow the non‐crack damage to be incorporated into design to achieve a much more global level of damage tolerance. The paper discusses the key differences between these non‐crack damage forms and the more traditional crack‐like defect which is used in current damage tolerance based structural integrity management approaches for these aircraft. These differences are associated principally with damage variability and damage location, and they challenge some aspects of our existing structural integrity design methods such as reliance on testing and analysis of supposedly ‘representative’ example of aircraft structure. The larger challenge is to fully exploit the principles of damage tolerant structural design and management, and the paper argues that to achieve this we need to maintain a move towards a broader, risk‐based approach to structural integrity management. This longer‐term goal will also involve a reappraisal of the nature and distribution of damage, and a fundamental shift in our crack‐centric view of structural integrity, additional diagnostic and prognostic tools for such damage would be essential for developing this transition to a more global risk‐based damage management approach.
Coherent gradient sensing (CGS) method for fracture mechanics: a review
Authors: TIPPUR H. V. 
Published: June 2010

ABSTRACTIt has been 20 years since the introduction of coherent gradient sensing (CGS) technique for studying fracture problems. In this article, an up‐to‐date review of this full‐field optical method as an experimental fracture mechanics tool is presented. The primary focus here is on contributions of the method to the advancement of fracture mechanics in general and dynamic fracture behaviour of materials in particular. Optical results published by various investigators using CGS to understand fracture of homogeneous materials, bimaterials, particulate composites, fibre reinforced composites and functionally graded materials are reviewed. A few promising new developments such as applications to load bearing problems and combining CGS with other full‐field optical methods to enhance its measurement capabilities are also visited.
Effects of ethnicity on diabetes incidence and prevention: results of the Diabetes REduction Assessment with ramipril and rosiglitazone Medication (DREAM) trial
Authors: Boyko E. J. , Gerstein H. C. , Mohan V. , Yusuf S. , Sheridan P. , Anand S. , Shaw J. E. ,   for the DREAM trial investigators
Published: June 2010

Diabet. Med. 27, 1226–1232 (2010)AbstractAims  Risk of Type 2 diabetes varies by ethnicity, but whether ethnicity remains important among those who have impaired glucose tolerance or impaired fasting glucose is uncertain. Whether the effect of thiazolidinedione treatment on diabetes prevention in persons with non‐diabetic dysglycaemia varies by ethnicity is also not known. We addressed these questions using data collected in the DREAM trial.Methods  A 2‐by‐2 factorial double‐blind randomized controlled trial to compare the effects of rosiglitazone and ramipril on the primary outcome of diabetes or death in persons meeting criteria for impaired glucose tolerance or impaired fasting glucose. The effect of these interventions by ethnicity was estimated using Cox regression analysis.Results  Of 5269 adults, 2365 were randomly assigned to rosiglitzone and 2634 to placebo. South Asians showed a higher hazard for the primary outcome compared with Europeans (hazard ratio, 95% confidence interval 2.21, 1.41–3.47) adjusted for age, gender, BMI, waist–hip ratio and geographic region. A lesser increase in risk was seen in Black people (1.37, 1.04–1.81). A significant reduction in risk of the primary outcome with rosiglitazone treatment assignment was seen in all ethnic groups, but the treatment effect significantly differed by ethnicity (P = 0.0242), with South Asians experiencing a smaller, and Latinos a larger preventive effect.Conclusions  Ethnicity is an important risk factor for Type 2 diabetes in dysglycaemic persons. All ethnic groups experienced a large significant reduction in diabetes risk because of rosiglitazone. The magnitude of this reduction differed by ethnicity. Given the post hoc nature of this analysis, further confirmation of these findings is needed.
Significance and application of melatonin in the regulation of brown adipose tissue metabolism: relation to human obesity
Authors: Tan D.‐X. , Manchester L. C. , Fuentes‐Broto L. , Paredes S. D. , Reiter R. J. 
Published: June 2010

SummaryA worldwide increase in the incidence of obesity indicates the unsuccessful battle against this disorder. Obesity and the associated health problems urgently require effective strategies of treatment. The new discovery that a substantial amount of functional brown adipose tissue (BAT) is retained in adult humans provides a potential target for treatment of human obesity. BAT is active metabolically and disposes of extra energy via generation of heat through uncoupling oxidative phosphorylation in mitochondria. The physiology of BAT is readily regulated by melatonin, which not only increases recruitment of brown adipocytes but also elevates their metabolic activity in mammals. It is speculated that the hypertrophic effect and functional activation of BAT induced by melatonin may likely apply to the human. Thus, melatonin, a naturally occurring substance with no reported toxicity, may serve as a novel approach for treatment of obesity. Conversely, because of the availability of artificial light sources, excessive light exposure after darkness onset in modern societies should be considered a potential contributory factor to human obesity as light at night dramatically reduces endogenous melatonin production. In the current article, the potential associations of melatonin, BAT, obesity and the medical implications are discussed.
Mast cells and MMP‐9 in the lamina propria during eruption of rat molars: quantitative and immunohistochemical evaluation
Authors: Cerri Paulo Sérgio , Pereira‐Júnior Jorge Alonso , Biselli Natalia Barrionuevo , Sasso‐Cerri Estela 
Published: June 2010

AbstractDuring the active tooth eruption process, structural changes in the lamina propria are necessary to provide extracellular matrix remodelling and for the establishment of the eruptive pathway. A large number of resident cells, recruited cells and proteases have been demonstrated in the eruptive process, but the participation of MMP‐9 and mast cells has not yet been demonstrated. In this study, we set out to evaluate the intensity of MMP‐9 immunoexpression, the frequency of mast cells and the correlation between the incidence of mast cells and bone resorption in different phases of tooth eruption. Fragments of maxilla containing first molars, obtained from 9‐, 11‐, 13‐ and 16‐day‐old rats, were fixed in 4% formaldehyde, decalcified and embedded in paraffin. Sagittal sections were stained with Masson’s trichrome or submitted to the tartrate‐resistant acid phosphatase method for quantification of osteoclasts. Sections stained by 1% toluidine blue were used for quantification of metachromatic mast cells mm−2 of lamina propria. The expression of MMP‐9 in the lamina propria was evaluated by immunohistochemistry. In the 9‐day‐old rats, the lamina propria contained few mast cells and occasional osteoclasts were found in the bone surface overlying the occlusal portion of the tooth germs. Otherwise, a significant increase in the number of mast cells was observed in the intra‐osseous phase of tooth eruption (11‐day‐old rats), period in which numerous TRAP‐positive osteoclasts were found in the bone surface. MMP‐9 immunolabelling was detected in fibroblasts, mast cells and macrophage‐like cells of the lamina propria in all ages studied. However, an enhanced immunolabelling was evident in the advanced phase of tooth eruption (16‐day‐old rats). During the intra‐osseous phase, the parallel between the high frequency of both mast cells and osteoclasts suggests that mast cells could exert a paracrine function on the osteoclasts and then stimulate bone resorption. The immunoexpression of MMP‐9 in different cells of lamina propria, including mast cells, indicates that this enzyme participates in the degradation of ECM, mainly during late phase of mucosal penetration. Thus mast cells and MMP‐9 are involved in the complex process of degradation of the eruptive pathway extracellular matrix.
Dynamic causal modeling of spontaneous fluctuations in skin conductance
Authors: Bach Dominik R. , Daunizeau Jean , Kuelzow Nadine , Friston Karl J. , Dolan Raymond J. 
Published: June 2010

AbstractSpontaneous fluctuations (SF) in skin conductance are often used to index sympathetic arousal and emotional states. SF are caused by sudomotor nerve activity (SNA), which is a direct indicator of sympathetic arousal. Here, we describe a dynamic causal model (DCM) of how SNA causes SF, and apply variational Bayesian model inversion to infer SNA, given empirically observed SF. The estimated SNA bears a relationship to the number of SF as derived from conventional (semi‐visual) analysis. Crucially, we show that, during public speaking induced anxiety, the estimated number of SNA bursts is a better predictor of the (known) psychological state than the number of SF. We suggest dynamic causal modeling of SF potentially allows a more precise and informed inference about arousal than purely descriptive methods.
Listening strategy for auditory rhythms modulates neural correlates of expectancy and cognitive processing
Authors: Snyder Joel S. , Pasinski Amanda C. , McAuley J. Devin 
Published: June 2010

AbstractA recently described auditory tempo perception paradigm revealed individual differences in perceived stimulus timing for identical stimulus sequences. The current study takes advantage of this paradigm by recording event‐related potentials (ERPs) concurrent with task performance in order to reveal brain responses that reflect individual differences in timing strategy. No strategy‐related differences were observed in sensory encoding of tones, as measured by the P1‐N1‐P2 complex. However, the contingent negative variation (CNV) leading up to the final tone of the sequence varied as a function of strategy, as did a parietal‐maximum late positive component (P3b) that occurred following the final tone. These data suggest that temporal expectancy for and cognitive processing of the final tone of rhythmic sequences underlies differences in strategy during rhythm perception.