634 research outputs found
Advanced oxide dispersion strengthened sheet alloys for improved combustor durability
Burner design modifications that will take advantage of the improved creep and cyclic oxidation resistance of oxide dispersion strengthened (ODS) alloys while accommodating the reduced fatigue properties of these materials were evaluated based on preliminary analysis and life predictions, on construction and repair feasibility, and on maintenance and direct operating costs. Two designs - the film cooled, segmented louver and the transpiration cooled, segmented twin Wall - were selected for low cycle fatigue (LCF) component testing. Detailed thermal and structural analysis of these designs established the strain range and temprature at critical locations resulting in predicted lives of 10,000 cycles for MA 956 alloy. The ODs alloys, MA 956 and HDA 8077, demonstrated a 167 C (300 F) temperature advantage over Hastelloy X alloy in creep strength and oxidation resistance. The MA 956 alloy was selected for mechanical property and component test evaluations. The MA 956 alloy was superior to Hastelloy X in LCF component testing of the film cooled, segmented louver design
Flow Instabilities in Feather Seals due to Upstream Harmonic Pressure Fluctuations
Feather seals (also called slot seals) typically found in turbine stators limit leakage from the platform into the core cavities and from the shroud to the case. They are of various geometric shapes, yet all are contoured to fit the aerodynamic shape of the stator and placed as close as thermomechanically reasonable the powerstream flow passage. Oscillations engendered in the compressor or combustor alter the steady leakage characteristics of these sealing elements and in some instances generate flow instabilities downstream of the seal interface. In this study, a generic feather seal geometry was studied numerically by imposing an upstream harmonic pressure disturbance on the simulated stator-blade gap. The flow and thermal characteristics were determined; it was found that for high pressure drops, large fluctuations in flows in the downstream blade-stator gap can occur. These leakages and pulsations in themselves are not all that significant, yet if coupled with cavity parameters, they could set up resonance events. Computationally generated time-dependent flow fields are captured in sequence video streaming
Brian Sutton-Smith Memorial Panel – A Celebration of the Life and Works of Brian Sutton-Smith
Serotonin-3 Receptors in the Posterior Ventral Tegmental Area Regulate Ethanol Self-Administration of Alcohol-Preferring (P) Rats
Several studies indicated the involvement of serotonin-3 (5-HT
3
) receptors in regulating alcohol-
drinking behavior. The objective of this study was to determine the involvement of 5-HT
3
receptors within the ventral tegmental area (VTA) in regulating ethanol self-administration by
alcohol-preferring (P) rats. Standard two-lever operant chambers were used to examine the effects
of 7 consecutive bilateral micro-infusions of ICS205-930 (ICS), a 5-HT
3
receptor antagonist,
directly into the posterior VTA on the acquisition and maintenance of 15% (v/v) ethanol self-
administration. P rats readily acquired ethanol self-administration by the 4
th
session. The three
highest doses (0.125, 0.25 and 1.25 ug) of ICS prevented acquisition of ethanol self-
administration. During the acquisition post-injection period, all rats treated with ICS demonstrated
higher responding on the ethanol lever, with the highest dose producing the greatest effect. In
contrast, during the maintenance phase, the 3 highest doses (0.75, 1.0 and 1.25 ug) of ICS
significantly increased responding on the ethanol lever; following the 7-day dosing regimen,
responding on the ethanol lever returned to control levels. Micro-infusion of ICS into the posterior
VTA did not alter the low responding on the water lever, and did not alter saccharin (0.0125%
w/v) self-administration.. Micro-infusion of ICS into the anterior VTA did not alter ethanol self-
administration. Overall, the results of this study suggest that 5-HT
3
receptors in the posterior VTA
of the P rat may be involved in regulating ethanol self-administration. In addition, chronic operant
ethanol self-administration, and/or repeated treatments with a 5-HT
3
receptor antagonist may alter
neuronal circuitry within the posterior VTA
Creating Creative Technologists: playing with(in) education
Since the industrial revolution, the organization of knowledge into distinct scientific, technical or creative categories has resulted in educational systems designed to produce and validate particular occupations. The methods by which students are exposed to different kinds of knowledge are critical in creating and reproducing individual, professional or cultural identities. (“I am an Engineer. You are an Artist”). The emergence of more open, creative and socialised technologies generates challenges for discipline-based education. At the same time, the term “Creative Technologies” also suggests a new occupational category (“I am a Creative Technologist”).
This chapter presents a case-study of an evolving ‘anti-disciplinary’ project-based degree that challenges traditional degree structures to stimulate new forms of connective, imaginative and explorative learning, and to equip students to respond to a changing world. Learning is conceived as an emergent process; self-managed by students through critique and open peer review. We focus on ‘playfulness’ as a methodology for achieving multi-modal learning across the boundaries of art, design, computer science, engineering, games and entrepreneurship. In this new cultural moment, playfulness also re-frames the institutional identities of teacher and learner in response to new expectations for learning
Antiepileptic drugs’ tolerability and safety – a systematic review and meta-analysis of adverse effects in dogs
<p>Various anti-epileptic drugs (AEDs) are used for the management of idiopathic epilepsy (IE) in dogs. Their safety profile is an important consideration for regulatory bodies, owners and prescribing clinicians. However, information on their adverse effects still remains limited with most of it derived from non-blinded non-randomized uncontrolled trials and case reports.</p><p><span>This poster won third place, which was presented at the Veterinary Evidence Today conference, Edinburgh November 1-3, 2016. </span></p><br /> <img src="https://www.veterinaryevidence.org/rcvskmod/icons/oa-icon.jpg" alt="Open Access" /
A funds of knowledge approach to examining play interests: listening to children’s and parents’ perspectives.
Children’s interests are widely recognised as pivotal to meaningful learning and play in the early years. However, less is known about how children’s diverse interests may contribute to relationships within peer cultures. This article builds upon previous studies to argue that participation in sociocultural activity generates interests informed by funds of knowledge that children reconstruct in their play. It reports findings from an interpretive study that used filmed footage of children’s play as a provocation to explore the perspectives of children, parents and teachers. The article presents original insights regarding some ways in which mutually constituted funds of knowledge afford opportunities for children to co-construct meaning within peer cultures. The findings also indicate that interests arising from diverse funds of knowledge may contribute to the interplay of power, agency and status during play. This raises some issues regarding how matters of inclusion and exclusion are understood and responded to within early years settings. The article recommends that teachers and researchers engage critically with children’s individual and collective funds of knowledge in order to better understand the complexities of play cultures
Gut Microbiome and Transcriptomic Changes in Cigarette Smoke-Exposed Mice Compared to COPD and CD Patient Datasets
Chronic obstructive pulmonary disease (COPD) patients and smokers have a higher incidence of intestinal disorders. The aim of this study was to gain insight into the transcriptomic changes in the lungs and intestines, and the fecal microbial composition after cigarette smoke exposure. Mice were exposed to cigarette smoke and their lung and ileum tissues were analyzed by RNA sequencing. The top 15 differentially expressed genes were investigated in publicly available gene expression datasets of COPD and Crohn’s disease (CD) patients. The murine microbiota composition was determined by 16S rRNA sequencing. Increased expression of MMP12, GPNMB, CTSK, CD68, SPP1, CCL22, and ITGAX was found in the lungs of cigarette smoke-exposed mice and COPD patients. Changes in the intestinal expression of CD79B, PAX5, and FCRLA were observed in the ileum of cigarette smoke-exposed mice and CD patients. Furthermore, inflammatory cytokine profiles and adhesion molecules in both the lungs and intestines of cigarette smoke-exposed mice were profoundly changed. An altered intestinal microbiota composition and a reduction in bacterial diversity was observed in cigarette smoke-exposed mice. Altered gene expression in the murine lung was detected after cigarette smoke exposure, which might simulate COPD-like alterations. The transcriptomic changes in the intestine of cigarette smoke-exposed mice had some similarities with those of CD patients and were associated with changes in the intestinal microbiome. Future research could benefit from investigating the specific mechanisms underlying the observed gene expression changes due to cigarette smoke exposure, focusing on identifying potential therapeutic targets for COPD and CD.</p
The therapeutic potential of resolvins in pulmonary diseases
Uncontrolled inflammation leads to nonspecific destruction and remodeling of tissues and can contribute to many human pathologies, including pulmonary diseases. Stimulation of inflammatory resolution is considered an important process that protects against the progression of chronic inflammatory diseases. Resolvins generated from essential omega-3 polyunsaturated fatty acids have been demonstrated to be signaling molecules in inflammation with important pro-resolving and anti-inflammatory capabilities. By binding to specific receptors, resolvins can modulate inflammatory processes such as neutrophil migration, macrophage phagocytosis and the presence of pro-inflammatory mediators to reduce inflammatory pathologies. The discovery of these pro-resolving mediators has led to a shift in drug research from suppressing pro-inflammatory molecules to investigating compounds that promote resolution to treat inflammation. The exploration of inflammatory resolution also provided the opportunity to further understand the pathophysiology of pulmonary diseases. Alterations of resolution are now linked to both the development and exacerbation of diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, acute respiratory distress syndrome, cancer and COVID-19. These findings have resulted in the rise of novel design and testing of innovative resolution-based therapeutics to treat diseases. Hence, this paper reviews the generation and mechanistic actions of resolvins and investigates their role and therapeutic potential in several pulmonary diseases that may benefit from resolution-based pharmaceuticals
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