145 research outputs found
An evaluation of earth banked tanks for slurry storage
End of project reportThis study examines the feasibility of using earth-banked tanks (EBT’s) as an alternative and economical means of winter storage for animal and other farmyard wastes. The study contains a detailed literature review on the subject, the results of a series of laboratory-scale experiments, field studies and a predictive model of the transport process through the soil liner of an earth-banked tank
Lipid coated liquid crystal droplets for the on-chip detection of antimicrobial peptides
We describe a novel biosensor based on phospholipid-coated nematic liquid crystal (LC) droplets and demonstrate the detection of Smp43, a model antimicrobial peptide (AMP) from the venom of North African scorpion Scorpio maurus palmatus. Mono-disperse lipid-coated LC droplets of diameter 16.7 ± 0.2 μm were generated using PDMS microfluidic devices with a flow-focusing configuration and were the target for AMPs. The droplets were trapped in a bespoke microfluidic trap structure and were simultaneously treated with Smp43 at gradient concentrations in six different chambers. The disruption of the lipid monolayer by the Smp43 was detected (<6 μM) at concentrations well within its biologically active range, indicated by a dramatic change in the appearance of the droplets associated with the transition from a typical radial configuration to a bipolar configuration, which is readily observed by polarizing microscopy. This suggests the system has feasibility as a drug-discovery screening tool. Further, compared to previously reported LC droplet biosensors, this LC droplet biosensor with a lipid coating is more biologically relevant and its ease of use in detecting membrane-related biological processes and interactions has the potential for development as a reliable, low-cost and disposable point of care diagnostic tool
Multi-layered collagen-based scaffolds for osteochondral defect repair in rabbits.
INTRODUCTION: Identification of a suitable treatment for osteochondral repair presents a major challenge due to existing limitations and an urgent clinical need remains for an off-the-shelf, low cost, one-step approach. A biomimetic approach, where the biomaterial itself encourages cellular infiltration from the underlying bone marrow and provides physical and chemical cues to direct these cells to regenerate the damaged tissue, provides a potential solution. To meet this need, a multi-layer collagen-based osteochondral defect repair scaffold has been developed in our group.
AIM: The objective of this study was to assess the in vivo response to this scaffold and determine its ability to direct regenerative responses in each layer in order to repair osteochondral tissue in a critical-sized defect in a rabbit knee.
METHODS: Multi-layer scaffolds, consisting of a bone layer composed of type I collagen (bovine source) and hydroxyapatite (HA), an intermediate layer composed of type I and type II collagen and HA; and a superficial layer composed of type I and type II collagen (porcine source) and hyaluronic acid (HyA), were implanted into critical size (3 × 5 mm) osteochondral defects created in the medial femoral condyle of the knee joint of New Zealand white rabbits and compared to an empty control group. Repair was assessed macroscopically, histologically and using micro-CT analysis at 12 weeks post implantation.
RESULTS: Analysis of repair tissue demonstrated an enhanced macroscopic appearance in the multi-layer scaffold group compared to the empty group. In addition, diffuse host cellular infiltration in the scaffold group resulted in tissue regeneration with a zonal organisation, with repair of the subchondral bone, formation of an overlying cartilaginous layer and evidence of an intermediate tidemark.
CONCLUSION: These results demonstrate the potential of this biomimetic multi-layered scaffold to support and guide the host reparative response in the treatment of osteochondral defects.
STATEMENT OF SIGNIFICANCE: Osteochondral defects, involving cartilage and the underlying subchondral bone, frequently occur in young active patients due to disease or injury. While some treatment options are available, success is limited and patients often eventually require joint replacement. To address this clinical need, a multi-layer collagen-based osteochondral defect repair scaffold designed to direct host-stem cell mediated tissue formation within each region, has been developed in our group. The present study investigates the in vivo response to this scaffold in a critical-sized defect in a rabbit knee. Results shows the scaffolds ability to guide the host reparative response leading to tissue regeneration with a zonal organisation, repair of the subchondral bone, formation of an overlying cartilaginous layer and evidence of an intermediate tidemark
Leisure constraints for adolescents in Cape Town, South Africa: a qualitative study
This study identified leisure constraints, constraints negotiation strategies, and their relative frequencies among 114 high school students from one under-resourced area of South Africa. Through focus group discussions, participants identified intrapersonal, interpersonal, structural, and sociocultural constraints to leisure, suggesting some degree of universality in this previously documented typology. Intrapersonal constraints were mentioned most often. Whereas participants readily identified ways to overcome interpersonal and structural constraints, strategies for overcoming intrapersonal and sociocultural constraints were not mentioned frequently, suggesting a potential need to help adolescents identify and employ these types of strategies.Web of Scienc
Reflecting on Pupil Learning to Promote Social Justice: A Catholic University’s Approach to Assessment
In contrast to current education policies that conceptualize pupil learning largely in terms of standardized exam scores, we offer an alternative view, one that conceives of pupil learning as a source of insight for pupils and teachers alike. Drawing on survey data and a qualitative study of the teacher candidate experience, we explore the following questions: In a teacher education program committed to promoting social justice, embracing an inquiry-into-practice stance, and affirming diversity by meeting the needs of diverse learners, how do teacher candidates assess pupil learning, in particular, how are their assessments influenced by these program themes? Further, how do they respond when dilemmas linked to pupil learning arise? Specifically, we focused on dilemmas two teacher candidates encountered that engendered a sense of “disequilibrium,” a feeling something was not quite right with their teaching. In turn, we consider how they responded”typically taking ownership of dilemmas and modifying their teaching, while occasionally distancing themselves from responsibility for pupil performance. To conclude, we discuss implications for teacher educators, and specifically for Catholic institutions of higher education that prepare teachers for both public and Catholic schools
Reflecting on Pupil Learning to Promote Social Justice: A Catholic University\u27s Approach to Assessment
In contrast to current education policies that conceptualize pupil learning largely in terms of standardized exam scores, we offer an alternative view, one that conceives of pupil learning as a source of insight for pupils and teachers alike. Drawing on survey data and a qualitative study of the teacher candidate experience, we explore the allowing questions: In a teacher education program committed to promoting social justice, embracing an inquiry-into-practice stance, and affirming diversity by meeting the needs of diverse learners, how do teacher candidates assess pupil learning, in particular, how are their assessments influenced by these program themes? Further, how do they respond when dilemmas linked to pupil learning arise? Specifically, we focused on dilemmas two teacher candidates encountered that engendered a sense of disequilibrium,” a feeling something was not quite right with their leaching. In turn; we consider how they responded-typically taking ownership of dilemmas and modifying their teaching, while occasionally distancing themselves from responsibility for pupil performance. To conclude, we discuss implications for teacher educators, and specifically for Catholic institutions of higher education that prepare teachers for both public and Catholic schools
Reflecting on Pupil Learning to Promote Social Justice: A Catholic University\u27s Approach to Assessment
In contrast to current education policies that conceptualize pupil learning largely in terms of standardized exam scores, we offer an alternative view, one that conceives of pupil learning as a source of insight for pupils and teachers alike. Drawing on survey data and a qualitative study of the teacher candidate experience, we explore the following questions: In a teacher education program committed to promoting social justice, embracing an inquiry-into-practice stance, and affirming diversity by meeting the needs of diverse learners, how do teacher candidates assess pupil learning, in particular, how are their assessments influenced by these program themes? Further, how do they respond when dilemmas linked to pupil learning arise? Specifically. we focused on dilemmas two teacher candidates encountered that engendered a sense of disequilibrium, a.feeling something was not quite right with their teaching. In turn, we consider how they responded - typically taking ownership of dilemmas and modifying their teaching, while occasionally distancing themselves from responsibility for pupil performance. To conclude, we discuss implications for teacher educators, and specifically for Catholic institutions of higher education that prepare teachers for both public and Catholic schools
Reflecting on Pupil Learning to Promote Social Justice: A Catholic University\u27s Approach to Assessment
In contrast to current education policies that conceptualize pupil learning largely in terms of standardized exam scores, we offer an alternative view, one that conceives of pupil learning as a source of insight for pupils and teachers alike. Drawing on survey data and a qualitative study of the teacher candidate experience, we explore the following questions: In a teacher education program committed to promoting social justice, embracing an inquiry-into-practice stance, and affirming diversity by meeting the needs of diverse learners, how do teacher candidates assess pupil learning, in particular, how are their assessments influenced by these program themes? Further, how do they respond when dilemmas linked to pupil learning arise? Specifically. we focused on dilemmas two teacher candidates encountered that engendered a sense of disequilibrium, a.feeling something was not quite right with their teaching. In turn, we consider how they responded - typically taking ownership of dilemmas and modifying their teaching, while occasionally distancing themselves from responsibility for pupil performance. To conclude, we discuss implications for teacher educators, and specifically for Catholic institutions of higher education that prepare teachers for both public and Catholic schools
Interpreting Early Career Trajectories
Career decisions of four teachers are explored through the concept of figured worlds in this qualitative, longitudinal case study. Participants were purposefully chosen for similarity at entry, with a range of career trajectories over time. Teacher career paths included remaining in one school, repeated changes in schools, attrition after relocation, and nonrenewal of contract. Data included interviews, observations, participants’ assessments, and pupils’ work. Cross-case analysis suggests that no single teacher attribute or workplace condition determined teachers’ career decisions; rather, teachers’ ability to refigure their identity within the figured world of teaching shaped career trajectory. Key factors such as ability to address disequilibrium, teacher identity, agency, and collaborative capacity are examined. Implications call for pre-service preparation and professional development to navigate cultures of schools, amended administrative involvement in teacher retention, and policy reform acknowledging the complexity of teachers’ figured worlds
Comparison of Discrete Variable and Continuous Variable Quantum Key Distribution Protocols with Phase Noise in the Thermal-Loss Channel
Discrete-variable (DV) quantum key distribution (QKD) based on single-photon detectors and sources have been successfully deployed for long-range secure key distribution. On the other hand, continuous-variable (CV) quantum key distribution (QKD) based on coherent detectors and sources is currently lagging behind in terms of loss and noise tolerance. An important discerning factor between DV-QKD and CV-QKD is the effect of phase noise, which is known to be more relevant in CV-QKD. In this article, we investigate the effect of phase noise on DV-QKD and CV-QKD protocols, including the six-state protocol and squeezed-state protocol, in a thermal-loss channel but with the assumed availability of perfect sources and detectors. We find that in the low phase noise regime but high thermal noise regime, CV-QKD can tolerate more loss compared to DV-QKD. We also compare the secret key rate as an additional metric for the performance of QKD. Requirements for this quantity to be high vastly extend the regions at which CV-QKD performs better than DV-QKD. Our analysis addresses the questions of how phase noise affects DV-QKD and CV-QKD and why the former has historically performed better in a thermal-loss channel
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