1,161 research outputs found
Pickering, Anne S.
No full text"Swamp Chestnut Oak, Quercus michauxii" In memory of Anne S. Pickering, R.N. Head Nurse, Gettysburg College Infirmary 1954 - 1958 Beloved mentor and friend Given by Kevin B Thomas '58 Robert B. Wolf '59Gift in MemoryTree; Plaque1958; 195
Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity
No full textCambra, Roberto A., Williams, Kevin A., Quintero, Diomedes, Windsor, Donald M., Pickering, John, Saavedra, Daisy (2018): Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity. Insecta Mundi 608: 1-17, DOI: http://doi.org/10.5281/zenodo.369706
Figure 30 in Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity
No full textFigure 30. Total Dasymutilla specimens captured by month in six years (2001 to 2006) with ten Malaise traps in BCI.Published as part of Cambra, Roberto A., Williams, Kevin A., Quintero, Diomedes, Windsor, Donald M., Pickering, John & Saavedra, Daisy, 2018, Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity, pp. 1-17 in Insecta Mundi 608 on page 17, DOI: 10.5281/zenodo.369706
Figure 1 in Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity
No full textFigure 1. Location of Malaise traps (red spots) on Barro Colorado Island [Modified from Foster and Brokaw 1990].Published as part of Cambra, Roberto A., Williams, Kevin A., Quintero, Diomedes, Windsor, Donald M., Pickering, John & Saavedra, Daisy, 2018, Dasymutilla Ashmead (Hymenoptera, Mutillidae) in Panama: new species, sex associations and seasonal flight activity, pp. 1-17 in Insecta Mundi 608 on page 14, DOI: 10.5281/zenodo.369706
Quantitative Morphological Characterization of Bicontinuous Pickering Emulsions via Interfacial Curvatures
No full textConfocal, X-ray CT and simulation data corresponding to corresponding paper in the journal Soft MatterBicontinuous Pickering emulsions (bijels) are a physically interesting class of soft materials with many potential applications including catalysis, microfluidics and tissue engineering. They are created by arresting the spinodal decomposition of a partially-miscible liquid with a (jammed) layer of interfacial colloids. Porosity L (average interfacial separation) of the bijel is controlled by varying the radius (r) and volume fraction (f) of the colloids (L ~ r/f). However, to optimize the bijel structure with respect to other parameters, e.g. quench rate, characterizing by L alone is insufficient. Hence, we have used confocal microscopy and X-ray CT to characterize a range of bijels in terms of local and area-averaged interfacial curvatures; we further demonstrate that bijels are bicontinuous using an image-analysis technique known as `region growing'. In addition, the curvatures of bijels have been monitored as a function of time, which has revealed an intriguing evolution up to 60 minutes after bijel formation, contrary to previous understanding.Reeves, Matthew; Stratford, Kevin; Thijssen, Job. (2016). Quantitative morphological characterization of bicontinuous Pickering emulsions via interfacial curvatures, [dataset]. University of Edinburgh, School of Physics and Astronomy, Institute of Condensed Matter and Complex Systems. http://dx.doi.org/10.7488/ds/1360
Diffusion across particle-laden interfaces in Pickering droplets
No full textEmulsions stabilized by nanoparticles, known as Pickering emulsions, exhibit remarkable stability, which enables applications ranging from encapsulation, to advanced materials, to chemical conversion. The layer of nanoparticles at the interface of Pickering droplets is a semi-permeable barrier between the two liquid phases, which can affect the rate of release of encapsulates, and the interfacial transfer of reactants and products in biphasic chemical conversion. A gap in our fundamental understanding of diffusion in multiphase systems with particle-laden interfaces currently limits the optimal development of these applications. To address this gap, we developed an experimental approach for in situ, real-time quantification of concentration fields in Pickering droplets in a Hele-Shaw geometry and investigated the effect of the layer of nanoparticles on diffusion of solute across a liquid–liquid interface. The experiments did not reveal a significant hindrance on the diffusion of solute across an interface densely covered by nanoparticles. We interpret this result using an unsteady diffusion model to predict the spatio-temporal evolution of the concentration of solute with a particle-laden interface. We find that the concentration field is only affected in the immediate vicinity of the layer of particles, where the area available for diffusion is affected by the particles. This defines a characteristic time scale for the problem, which is the time for diffusion across the layer of particles. The far-field concentration profile evolves towards that of a bare interface. This localized effect of the particle hindrance is not measurable in our experiments, which take place over a much longer time scale. Our model also predicts that the hindrance by particles can be more pronounced depending on the particle size and physicochemical properties of the liquids and can ultimately affect performance in applications.ChemE/Transport Phenomen
Shifting and persosting in the face of failure: Learning from what did not work
No full textSocial justice activism demands coordinated, concentrated efforts to move the needle in a positive direction. In the author's nine years as a social justice educator, he led multiple large- and small-scale projects for social justice within higher education. In many ways, those efforts failed to create a lasting impact. In the higher education ecosystem, they also took away time from the kind of promotable work which would benefit his case for tenure and promotion. Trying - and failing - to effect institutional changes left him emotionally, psychologically, and physically exhausted. Beyond that, he suffered from feelings of loneliness, exclusion, and lack of direction. For a long time, the author blamed himself for the failure to change the institution to be a place in which he felt comfortable. He also failed to cope with these negative experiences and emotions, often seething in frustration or anger or avoiding similar situations of vulnerability or creativity. It took years for him to remember and internalize lessons of persistence and shifting appraisals in order to maintain motivation for action and survive the stressors of working within an oppressive system.Published versio
Board of County Commissioners v. Umbehr: The Inadequacies of Extending Pickering Analysis to Government Contractors
No full textThis Note challenges the restrictive First Amendment free speech protection that the Supreme Court gave to government contractors in Board of County Commissioners v. Umbehr when it applied the Pickering balancing test, developed nearly thirty years ago in Pickering v. Board of Education in the context of government employees. It does so by first questioning whether the First Amendment free speech protections given to government employees should be similar for government contractors. It then explores whether the Pickering balancing test should be applied to cases involving government contractors as it was in Umbehr.
The author concludes that the Court improperly restricted the First Amendment free speech rights of government contractors by failing to take into account the numerous modifications the Court has made to the Pickering balancing test that have gradually eroded the broader protections of Pickering and by failing to account for the potentially significant differences between public employees and government contractors. The author thus proposes a new test that would both incorporate the Court\u27s views regarding the free speech rights of government employees and account for the potentially significant differences between public employees and government contractors
CHALLENGING SCIENCE: ISSUES FOR NEW ZEALAND SOCIETY IN THE 21ST CENTURY
No full textAcknowledgements -- Ch. 1. Introduction: The challenges of challenging science / Ruth Fitzgerald and Kevin Dew -- Pt. I. The challenge of communication and public participation -- Ch. 2. Shared contemplations: how a science policy ministry is responding to science under challenge / Marten Hutt -- Ch. 3. Challenging scientific legitimacy: citizen participation and technoscience / Joanna Goven and Julie Wuthnow -- Ch. 4. Science, public participation and spin / Ted Ninnes -- Ch. 5. Boundary critique and community involvement in watershed management / Virginia Baker, Jeff Foote, Jan Gregor, Don Houston, and Gerald Midgley -- Pt. II. The social shaping of science and the challenge of objectivity -- Ch. 6. Valuing Māori ways of knowing and being / Tai Walker and Ngati Porou -- Ch. 7. Cultural conflict and new biotechnologies: what is at risk? / Anne Scott and Bevan Tipene-Matua -- Ch. 8. Frontier science: the early investigation of kuru in Papua and New Guinea / Annette Beasley -- Ch. 9. The Quantum Booster and medical orthodoxy / Neil Pickering -- Ch. 10. Academic freedom and its limits / Kevin Dew -- Ch. 11. Margarine regulation: a political economy of risk and safety / Ruth Fitzgerald, Joanna Wylie, Raewyn Crump, and Hugh Campbell -- Pt. III. Complex questions and challenging answers -- Ch. 12. Scientific controversies: debate and dissent / Andy Pratt -- Ch. 13. Challenges to regulating the industrial gene: views inspired by the New Zealand experience / J.A. Heinemann -- Ch. 14. Looking at a challenged science: The politically charged atmosphere of weather modification / Steve Matthewman -- Ch. 15. Concluding comment / Kevin Dew and Ruth Fitzgerald -- Index -- Contributor
Fabrication of edible biocompatible carbohydrate particle-based Pickering emulsions
No full textDifferent from conventional emulsions, Pickering emulsions are stabilized by interfacially-adsorbed solid particles. Pickering emulsions have gained great interest in the past decades due to their high stability against coalescence, Ostwald ripening, and the possibility to avoid the deleterious effects linked to emulsifiers used in conventional emulsions. To fulfill the strong market trend of formulating products that are not only edible in theory, but also maintain the consumer perception of being natural, “clean label” and “green”, this study was dedicated to developing particles from biomass-based resources to form Pickering emulsions with potential application in food, cosmetic and pharmaceutic products. As a simple, organic solvent-free process, media-milling was applied to modify two major biomass materials, native starch and cellulose. Three maize starches (normal maize starch, high-amylose maize starch and waxy maize starch) with different amylose/amylopectin ratios were physically modified through media milling process to form milled starch particles. The physiochemical properties of these starches during milling process, including particle size, crystallinity and gelatinization properties were studied. Emulsions stabilized by milled starch particles with different amylose/amylopectin ratios exhibited significant difference in terms of stabilization capability and rheological properties. Milled high-amylose maize starch particles have the best stabilization ability, followed by milled normal maize starch particles. Furthermore, the stabilization capacity of the milled starch particles improves with the increase of milling time. To investigate the feasibility of Pickering emulsions stabilized by milled starch as a novel food-grade formulation for encapsulation and delivery of lipophilic bioactive compounds, curcumin was selected as model delivery target and encapsulated in the oil phase of Pickering emulsion. The digestion profile of curcumin-loaded Pickering emulsion was studied using three in vitro digestion models, simulated static small intestinal digestion model, pH-stat lipolysis model and TNO’s gastrointestinal model (TIM-1). Simulated static small intestinal digestion model and pH-stat model indicated that the bioaccessibility of curcumin encapsulated in Pickering emulsion was enhanced compared with free curcumin suspended in bulk oil phase. A significant improvement of curcumin bioaccessbility was also observed in an emulsion system vs in bulk oil when using TIM-1 model, which simulates the entire human GI tract. Overall, the study's findings showed that curcumin encapsulated in Pickering emulsion stabilized by milled starch possesses benign stability against harsh gastric conditions as well as improved dissolution profiles in small intestinal tract. All are suggested that Pickering emulsion stabilized by milled starch exhibit high potential as encapsulate and delivery system for lipophilic bioactive compounds. Milled cellulose particles of sizes ranging from 38 nm to 671 nm with rod-like shapes have also been successfully fabricated using media milling. Media milling process led to a notable decrease in the particle size and crystallinity of milled cellulose particles with the increase of milling time. The milled cellulose particles were irreversibly adsorbed at the oil/water interface and formed stable emulsions with droplet size around 60~42 µm, which exhibited benign stability over a month storage. Milled cellulose stabilized emulsions also exhibited good stability against a wide range of pH (3, 5, 7, 9) and salt conditions (0.1~100 mM) with slight change in the droplet size. The rheological tests indicated the formation of gel network in the emulsions, which promoted the stability of the emulsions. The in vitro digestion profile and phase behavior of Pickering emulsions stabilized by milled cellulose were evaluated to investigate their feasibility for encapsulation and delivery of lipophilic bioactive compounds. Curcumin encapsulated in Pickering emulsions exhibited benign stability with less than 50% degraded after storage of 30 days. The digestion behavior of emulsions under simulated small intestinal conditions was characterized using a pH-stat lipolysis model. The digestion profiles of emulsions were markedly dependent on the type of lipid and digestion buffer employed in lipid digestion experiments. The rate and extent of lipolysis of emulsions with medium chain triglycerides (MCT) was greater than emulsions with long chain triglycerides (soy bean and canola oil), reaching complete hydrolysis during lipolysis process independent of bile salt and phospholipids concentration. The structure changes of emulsions during digestion were analyzed using optical and fluorescent imaging. Although the initial digestion rate of curcumin encapsulated in Pickering emulsions with soy bean and canola oil was slower than the corresponding conventional emulsions stabilized by Tween/Span, their total extent of lipolysis was higher than that of conventional emulsions under both fasted and fed intestinal digestion conditions. The bioaccessibility of curcumin encapsulated in Pickering emulsions was higher than in corresponding surfactant stabilized conventional emulsions. High-amylose maize starch with different fatty acids (C12:0, C14:0, C16:0, C18:0, C18:1) were complexed using two heat-moisture methods. The structure properties of different starch-fatty acid complexes, including size and shapes of nanoscale supramolecular structures formed, through heat and moisture treatment, were studied. Optical microscope and SEM analysis showed that starch-fatty acid complexes retained the Maltese cross and granular morphology of native starch. X-ray diffraction revealed the crystalline morphology of starch-fatty acid complexes with B- and V-type crystallinity. And the crystallinity of the complexes varied depending on the fatty acids and methods used. USAXS/SAXS experiments demonstrated that fatty acid chain length and level of saturation affected both the lamellar structure as well as the B-type crystalline of the complexes. Moreover, the processing methods also exhibited major influence on the nanostructure of complexes. The resistance of these starch complexes against enzymatic hydrolysis was increased based on the in vitro digestion measurements. And the hydrophobicity of these complexes was enhanced. This was manifested by increased contact angles. The capacity of these starch-fatty acid complexes to form Pickering emulsions was characterized. Starch-saturated fatty acid complexes were able to form stable emulsions that endured heat treatment of 60, 80 and 100℃. However, starch-unsaturated fatty acid complexes could not form stable emulsions. The barrier properties of these emulsions could be adjusted by heat treatment, which led to swelling of starches. Lipolysis profile of PMFs loaded emulsions suggested that certain heat treatment could reduce the accessibility of lipase towards oil droplets and release of PMFs during lipolysis by enhancing the coverage of granules onto the oil-water interface. In conclusion, particles derived from biomass resources starch and cellulose have been successfully fabricated to form Pickering emulsions using simple, environmental-friendly procedures. The resulting formulations were edible, ‘green’, have exhibited exceptional stability and a practical potential to encapsulate and control release of lipophilic ingredients, making them suitable for various applications in cosmetic, food and pharmaceutical industry.Ph.D.Includes bibliographical referencesby Xuanxuan L
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