192 research outputs found
Implementing an Extensive Reading Program in an Intensive University EAP Curriculum
The goal of this project was to integrate an extensive reading (ER) program within an existing 8-week intensive reading curriculum in a university English for academic purposes (EAP) program. The merits of both intensive and extensive reading approaches were examined and used to develop the methodology for the ER program. Additionally, implementation parameters, as agreed upon by the EAP program director and academic coordinator, were used to determine the design and implementation of the ER program that was piloted on a low-intermediate level reading class. A method of anonymous student feedback, via questionnaires and reading logs, were developed and applied before, during, and after the project to determine if the implementation of the ER program met the implementation parameters
Rupture of Stochastically Occurring Vesicle Clusters Limits Bilayer Formation on Alkane-PEG-Type Supports:Uncoupling Clustering from Surface Coverage
Polymer-supported
bilayers (PSBs) are a recognized tool for drug
discovery through function-interaction analysis of membrane proteins.
While silica-supported bilayers (SSBs) spontaneously form from surface-adsorbed
vesicles, successful PSB formation via a similar method has thus far
been limited by an insufficient understanding of the underlying vesicle-remodelling
processes. Here, we generated a polymer support through the incubation
of poly-l-lysine conjugated to alkyl-chain-terminated polyÂ(ethylene)Âglycol
on silica. This polymer-coated silica substrate yielded efficient
vesicle adsorption and spontaneous bilayer formation, thereby providing
a rare opportunity to address the mechanism of PSB formation and compare
it to that of SSB. The combined use of super-resolution imaging, kinetics,
and simulations indicates that the rupture of stochastically formed
vesicle clusters is the rate-limiting step, which is an order of magnitude
higher for silica than for polymer-coated silica. This was confirmed
by directly demonstrating increased rupture rates for surface adsorbed
multivesicle assemblies formed by vesicle cross-linking in solution.
On the basis of this key insight we surmised that a low propensity
of cluster rupture can be compensated for by an increase in the number
density of clusters: the deposition of a mixture of oppositely charged
vesicles resulted in bilayer formation on another alkane–PEG
type of interface, which despite efficient vesicle adsorption otherwise
fails to support spontaneous bilayer formation. This potentially provides
a universal strategy for promoting bilayer formation on resistant
surfaces without resorting to modifying the surface itself. Therefore,
multivesicle assemblies with tailored geometries not only could facilitate
bilayer formation on polymers with interesting functional properties
but also could instigate the exploration of vesicle architecture for
other processes involving vesicle remodelling such as drug delivery
The responses of Tribolium castaneum to wheat germ oil and fungal produced volatiles: Presentation
The red flour beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is a significant pest affecting a wide variety of different stored products around the Globe. Despite its economic impact, there is evidence that the lures currently used in traps to monitor for this species are largely ineffective. Based on the evolutionary history of T. castaneum, and the ecological niche it occupies, the volatiles of wheat germ oil and volatiles produced by grain-associated fungi have the potential to act as attractants for this species. We used electroantennography (EAG) to measure the electrophysiological response elicited by sixty-eight volatile compounds found in wheat germ oil and/or grain-associated fungi in two T. castaneum strains; an established lab population (CTC12 strain) and a recently caught wild population. Many volatile compounds from both sources elicited strong antennal depolarisations, and the responses of both strains were highly correlated. We then tested whether the compounds that triggered the strongest antennal depolarisations also elicited behavioural responses by using Y-tube olfactometer bioassays and identified several compounds attractive to both strains. The discovery of novel compounds that elicit strong EAG signals and behavioural responses could prove useful in the design of improved lures for T. castaneum and other stored product pests. Our future research will identify how effective these attractive volatiles might be when used in combination, and when used under conditions that more closely replicate a stored product environment.The red flour beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is a significant pest affecting a wide variety of different stored products around the Globe. Despite its economic impact, there is evidence that the lures currently used in traps to monitor for this species are largely ineffective. Based on the evolutionary history of T. castaneum, and the ecological niche it occupies, the volatiles of wheat germ oil and volatiles produced by grain-associated fungi have the potential to act as attractants for this species. We used electroantennography (EAG) to measure the electrophysiological response elicited by sixty-eight volatile compounds found in wheat germ oil and/or grain-associated fungi in two T. castaneum strains; an established lab population (CTC12 strain) and a recently caught wild population. Many volatile compounds from both sources elicited strong antennal depolarisations, and the responses of both strains were highly correlated. We then tested whether the compounds that triggered the strongest antennal depolarisations also elicited behavioural responses by using Y-tube olfactometer bioassays and identified several compounds attractive to both strains. The discovery of novel compounds that elicit strong EAG signals and behavioural responses could prove useful in the design of improved lures for T. castaneum and other stored product pests. Our future research will identify how effective these attractive volatiles might be when used in combination, and when used under conditions that more closely replicate a stored product environment
The influence of temperature on hydrogen environmentally assisted cracking of AA7449-T7651 in moist air
Development of a microstructural cohesive zone model for intergranular hydrogen environmentally assisted cracking
Direct observation of elastic and plastic strain fields during ductile tearing of a ferritic steel
3D characterisation of hydrogen environmentally assisted cracking during static loading of AA7449-T7651
In this investigation, synchrotron X-ray microtomography was used to perform 3D in situ observations of crack initiation and growth during hydrogen environmentally assisted cracking (HEAC) in tensile samples of AA7449-T7651. Two smooth tensile samples with a 1 mm diameter gauge section were held at a fixed displacement (≈30% of yield stress) in warm, moist air (≈76∘C, 73% relative humidity). The samples were then imaged repeatedly using X-ray tomography until they fractured completely. The tomograms showing the nucleation and evolution of intergranular cracks were correlated with electron microscopy fractographs. This enabled the identification of crack initiation sites and the characterisation of the crack growth behaviour relative to the microstructure. The samples were found to fracture within an environmental exposure time of 240 min. Some cracks in both samples nucleated within an exposure time of 80 min (33–40% of the total lifetime). Many cracks were found to nucleate both internally and at the sample surface. However, only superficial cracks contributed to the final fracture surface as they grew faster owing to the direct environmental exposure and the larger crack opening. HEAC occurred prominently via brittle intergranular cracking, and cracks were found to slow down when approaching grain boundary triple junctions. Additionally, crack shielding from nearby cracks and the presence of coarse Al–Cu–Fe particles at the grain boundaries were also found to temporarily reduce the crack growth rates. After prolonged crack growth, the HEAC cracks displayed ductile striations and transgranular fracture, revealing a change in the crack growth mechanism at higher stress intensity factors
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