Identification of Damage and Plasticity Parameters for Continuum Damage Mechanics Modelling of Carbon and Glass Fibre‐Reinforced Composite Materials

Abstract: An experimental test series was carried out to determine input parameters for a well‐known continuum damage mechanics elementary ply plasticity model. A full suite of data was obtained for a carbon fibre and an S2‐glass fibre‐reinforced composite material, both currently used in the aerospace industry. Models were implemented using the experimentally determined input parameters and predictions for in‐plane behaviour found good agreement with experiments for both material systems. In addition, model predictions for cyclic loading accurately captured reload moduli and plastic strain magnitude.     

Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

Sulfur‐doped graphene (SG) is prepared by a thermal shock/quench anneal process and investigated as a unique Pt nanoparticle support (Pt/SG) for the oxygen reduction reaction (ORR). Particularly, SG is found to induce highly favorable catalyst‐support interactions, resulting in excellent half‐cell based ORR activity of 139 mA mg_Pt ^?1 at 0.9 V vs RHE, significant improvements over commercial Pt/C (121 mA mg_Pt ^?1) and Pt‐graphene (Pt/G, 101 mA mg_Pt ^?1). Pt/SG also demonstrates unprecedented stability, maintaining 87% of its electrochemically active surface area following accelerated degradation testing. Furthermore, a majority of ORR activity is maintained, providing 108 mA mg_Pt ^?1, a remarkable 171% improvement over Pt/C (39.8 mA mg_Pt ^?1) and an 89% improvement over Pt/G (57.0 mA mg_Pt ^?1). Computational simulations highlight that the interactions between Pt and graphene are enhanced significantly by sulfur doping, leading to a tethering effect that can explain the outstanding electrochemical stability. Furthermore, sulfur dopants result in a downshift of the platinum d‐band center, explaining the excellent ORR activity and rendering SG as a new and highly promising class of catalyst supports for electrochemical energy technologies such as fuel cells.     

Perception of variability in category development: Instance- versus abstraction-based stereotypes.

We conducted two experiments to investigate the acquisition and representation of social categories, with an emphasis on the perception of variability of group members. In Experiment 1, subjects learned about a group that was sociable and intelligent and either high or low in variability with respect to these attributes. Differences in the actual variability of group members were reflected in subjects' estimates of variability, in their tendency to generalize from the traits and goals of a single member to the entire group, and in their classification judgments of new instances, which reflected their expectations of group members' future behavior. Memory for instances of the category also played a role in these judgment tasks. In Experiment 2, subjects who first learned about the behaviors performed by group members and then about general characteristics of the group perceived the group as more variable than did those who learned the same information in the reverse order. In both experiments, we manipulated memory for specific behaviors such that either the most extreme behaviors or behaviors at the center of the distribution were most memorable. This manipulation did not affect estimates of perceived variability, suggesting that these were constructed and stored on-line rather than from a retrieved set of category exemplars. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Approach and avoidance strength during goal attainment: regulatory focus and the "goal looms larger" effect

Three studies tested the hypothesis that regulatory focus, both as a chronic person variable and as a manipulated situational variable, differentially affects the strength of participants' approach and avoidance strategic motivations as they get closer to the goal. In 2 studies, flexion and extension arm pressure were used as on-line measures of approach and avoidance intensity, respectively. As predicted, the approach gradient was steeper for participants with a promotion focus on aspirations and gains than for participants with a prevention focus on responsibilities and nonlosses, whereas the reverse was true for the avoidance gradient. In a third study, the same pattern of results was found on a persistence measure of motivational strength. Participants with a promotion focus worked longer on anagrams closer to the goal when they were approach means for goal attainment than when they were avoidance means, whereas the reverse was true for participants with a prevention focus.     

A controlled trial of twice daily triamcinolone oral inhaler in patients with mild-to-moderate asthma

The objectives of this work was to (1) study the bone mineral density (BMD) of the lumbar spine, total skeleton, and body composition in patients with primary biliary cirrhosis (PBC) and (2) evaluate the risk factors (premature menopause, stages of the disease, hyperbilirubinemia) and bone and liver biochemical parameters for the development of osteoporosis. We studied 23 women with a compatible diagnosis of PBC. The BMD and body composition were evaluated by X-ray absorptiometry (Lunar DPX-L). The average age of the population was 56.7 +/- 10.2 years. The BMD of the lumbar spine and of the total skeleton was 1.3 SDs below the normal population matched for sex and age. In the total skeleton, the legs were the most severely affected area (Z score -1.5). The body composition showed no significant difference compared with the normal population. The BMD of 56% of the patients was less than -2.5 SDs from the average normal young values. Patients with a history of vertebral fractures had diminished mineral density of the lumbar spine, as did those who had had no fractures. Of the risk factors studied, patients with premature menopause had a lower bone mass compared with patients with normal menopausal age (Z score of the total skeleton was -2.1 +/- 1.8 versus -1.1 +/- 1.0) but the difference did not reach statistical significance. The bone mass was not affected in patients with regular menstrual cycles. There were no statistically significant differences in high levels of bilirubin, advanced stages of the disease, or the biochemical variables studied. It is concluded that patients with primary biliary cirrhosis present diminished cortical and trabecular bone mass, whereas body composition was unaffected. Premature hormone deficit, possibly triggered by the chronic hepatic pathology, is a contributing factor to the osteoporosis in this population.     

Sequence ordinations: a multivariate analysis approach to analysing large sequence data sets.

Ordination is a powerful method for analysing complex data sets but has been largely ignored in sequence analysis. This paper shows how to use principal coordinates analysis to find low-dimensional representations of distance matrices derived from aligned sets of sequences. The method takes a matrix of Euclidean distances between all pairs of sequence and finds a coordinate space where the distances are exactly preserved. The main problem is to find a measure of distance between aligned sequences that is Euclidean. The simplest distance function is the square root of the percentage difference (as measured by identities) between two sequences, where one ignores any positions in the alignment where there is a gap in any sequence. If one does not ignore positions with a gap, the distances cannot be guaranteed to be Euclidean but the deleterious effects are trivial. Two examples of using the method are shown. A set of 226 aligned globins were analysed and the resulting ordination very successfully represents the known patterns of relationship between the sequences. In the other example, a set of 610 aligned 5S rRNA sequences were analysed. Sequence ordinations complement phylogenetic analyses. They should not be viewed as a complete alternative.     

Compartmentalization of Th1/Th2 cytokine responses to experimental Yersinia pseudotuberculosis infection in cats

Specific pathogen-free cats were inoculated subcutaneously into the drainage areas of the left auricular and popliteal lymph nodes with living Yersinia pseudotuberculosis. Inflammation was evident at the inoculation sites and the regional lymph nodes were palpably enlarged at 48 h post-infection. Lymph node enlargement was due to marked paracortical lymphoid hyperplasia and variable neutrophil infiltrates. Yersinia was cultured from the regional lymph nodes and/or spleens of three of the six cats, indicating systemic spread of bacteria. Specific T-helper 1 and 2 (Th1, Th2) cell-associated cytokine mRNA levels were compared in regional lymph nodes, peripheral blood mononuclear cells (PBMC) and spleen at 48 h post-inoculation. Relative to unstimulated control tissues, there was a significant increase in TNF-alpha, IFN-gamma, IL-12, and IL-10 mRNAs in spleen with down-regulation of IL-4. Significant up-regulation of TNF-alpha and down-regulation of IL-4 were also observed in PBMC. Paradoxically, 48 h stimulated lymph nodes showed only minimal differences in cytokine mRNA expression when compared to lymph nodes from mock-inoculated control animals or unchallenged contralateral lymph nodes from the same animal. This study demonstrated that cats, like mice, respond to an intracellular pathogen such as Y pseudotuberculosis with a predominantly Th1-type immune response. The cytokine responses in regional lymph nodes and spleen were asynchronous, while cytokine stimulation in cells of the spleen was mirrored by PBMC.     

Novel, ultraslow inactivating sodium current in human ventricular cardiomyocytes

BACKGROUND: Alterations in K+ channel expression and gating are thought to be the major cause of action potential remodeling in heart failure (HF). We previously reported the existence of a late Na+ current (INaL) in cardiomyocytes of dogs with chronic HF, which suggested the importance of the Na+ channel in this remodeling process. The present study examined whether this INaL exists in cardiomyocytes isolated from normal and failing human hearts. METHODS AND RESULTS: A whole-cell patch-clamp technique was used to measure ion currents in cardiomyocytes isolated from the left ventricle of explanted hearts from 10 patients with end-stage HF and from 3 normal hearts. We found INaL was activated at a membrane potential of -60 mV with maximum density (0.34+/-0.05 pA/pF) at -30 mV in cardiomyocytes of both normal and failing hearts. The steady-state availability was sigmoidal, with an averaged midpoint potential of -94+/-2 mV and a slope factor of 6.9+/-0.1 mV. The current was reversibly blocked by the Na+ channel blockers tetrodotoxin (IC50=1.5 micromol/L) and saxitoxin (IC50=98 nmol/L) in a dose-dependent manner. Both inactivation and reactivation of INaL had an ultraslow time course (tau approximately 0.6 seconds) and were independent of voltage. The amplitude of INaL was independent of the peak transient Na+ current. CONCLUSIONS: Cardiomyocytes isolated from normal and explanted failing human hearts express INaL characterized by an ultraslow voltage-independent inactivation and reactivation.