Quantitative in vivo analysis of ligand-receptor interactions in the Wnt signalling network

The Wnt family of proteins are secreted glycoproteins with significant palmitoleate post-translation modification that renders each Wnt protein hydrophobic. Wnt proteins are a class of morphogens whose role is to be secreted and dispersed within the tissue to elicit a wide range of cellular responses based on the concentration of the ligand. However, as Wnt proteins are hydrophobic, standard diffusion through the aqueous extracellular environment is severely reduced. Indeed, alternative methods are required to aid dispersal and prevent aggregation. One such method involves active extension and protrusion of cell surface membrane by actin rich structures called cytonemes. These cytonemes have been characterised in the literature and several proteins are known to play an important role in their function and regulation. Indeed, Wnt protein over-expression and reception directly modulates cytoneme number, length and polarity of the cell to bias cytoneme direction in growth. However, to date, there has been no unbiased identification of the proteome surrounding cytoneme mediated Wnt handover. To address this, I developed a novel GFP-binding nanobody-directed biotin ligase system to extract and identify proteins specifically on cell surface membrane and cytoneme protrusions involved in the Wnt handover. I generated this assay from the ground up; exploring different cell cultures, biotin ligase constructs, methods of application and optimisations. This methods development was subject to a series of mass spectrometry analyses, which culminated in the identification of Caveolin1 as a protein hit to Wnt5a. Further protein hits were also suggested and investigated for possible co-localisation to Wnt5a, demonstrating the success of the assay. While further improvements are necessary, this thesis demonstrates the success of the novel nanobody-biotin ligase assay and its applicability to a wide range of proteins of interest.Biotechnology and Biological Sciences Research Counci

Through Faculty\u27s Eyes: Teaching Threshold Concepts and the Framework

This study investigates faculty perceptions of teaching information literacy. Using 24 semi-structured interviews, a phenomenographic approach identified four qualitative ways in which faculty experienced teaching information literacy (IL). This paper analyzes the challenging information literacy concepts that faculty identify—known to many librarians as threshold concepts— and their relationship to the Association of College and Research Libraries (ACRL) “Framework for Information Literacy for Higher Education.” The study highlights the transdisciplinary nature of IL instruction and indicates that, although unaware of the ACRL Framework, faculty already teach at least three concepts from that document. This finding suggests new opportunities for collaborations between librarians and faculty

Micrometeorological processes driving snow ablation in an Alpine catchment

Mountain snow covers typically become patchy over the course of a melting season. The snow pattern during melt is mainly governed by the end of winter snow depth distribution and the local energy balance. The objective of this study is to investigate micrometeorological processes driving snow ablation in an Alpine catchment. For this purpose we combine a meteorological model (ARPS) with a fully distributed energy balance model (Alpine3D). Turbulent fluxes above melting snow are further investigated by using data from eddy-correlation systems. We compare modelled snow ablation to measured ablation rates as obtained from a series of Terrestrial Laser Scanning campaigns covering a complete ablation season. The measured ablation rates indicate that the advection of sensible heat causes locally increased ablation rates at the upwind edges of the snow patches. The effect, however, appears to be active over rather short distances except for very strong wind conditions. Neglecting this effect, the model is able to capture the mean ablation rates for early ablation periods but strongly overestimates snow ablation once the fraction of snow coverage is below a critical value. While radiation dominates snow ablation early in the season, the turbulent flux contribution becomes important late in the season. Simulation results indicate that the air temperatures appear to overestimate the local air temperature above snow patches once the snow coverage is below a critical value. Measured turbulent fluxes support these findings by suggesting a stable internal boundary layer close to the snow surface causing a strong decrease of the sensible heat flux towards the snow cover. Thus, the existence of a stable internal boundary layer above a patchy snow cover exerts a dominant control on the timing and magnitude of snow ablation for patchy snow covers.<br/

Pressure Shifts in High-Precision Hydrogen Spectroscopy: I. Long-Range Atom-Atom and Atom-Molecule Interactions

We study the theoretical foundations for the pressure shifts in high-precision atomic beam spectrosopy of hydrogen, with a particular emphasis on transitions involving higher excited P states. In particular, the long-range interaction of an excited hydrogen atom in a 4P state with a ground-state and metastable hydrogen atom is studied, with a full resolution of the hyperfine structure. It is found that the full inclusion of the 4P_1/2 and 4P_3/2 manifolds becomes necessary in order to obtain reliable theoretical predictions, because the 1S ground state hyperfine frequency is commensurate with the 4P fine-structure splitting. An even more complex problem is encountered in the case of the 4P-2S interaction, where the inclusion of quasi-degenerate 4S-2P_1/2 state becomes necessary in view of the dipole couplings induced by the van der Waals Hamiltonian. Matrices of dimension up to 40 have to be treated despite all efforts to reduce the problem to irreducible submanifolds within the quasi-degenerate basis. We focus on the phenomenologically important second-order van der Waals shifts, proportional to 1/R^6 where R is the interatomic distance, and obtain results with full resolution of the hyperfine structure. The magnitude of van der Waals coefficients for hydrogen atom-atom collisions involving excited P states is drastically enhanced due to energetic quasi-degeneracy; we find no such enhancement for atom-molecule collisions involving atomic nP states, even if the complex molecular spectrum involving ro-vibrational levels requires a deeper analysis.Comment: 32 pages; 2 figures; this is part 1 of a series of two papers; part 1 carries article number 075005, while part 2 carries article number 075006 in the journal (online journal version has been rectified). arXiv admin note: text overlap with arXiv:1711.1003

Time Spent Working in Custody Influences Work Sample Test Battery Performance of Deputy Sheriffs Compared to Recruits

This study determined the influence of years spent working in custody on fitness measured by a state-specific testing battery (Work Sample Test Battery; WSTB) in deputy sheriffs. Retrospective analysis was conducted on one patrol school class (51 males, 13 females) divided into three groups depending on time spent working in custody: DS24 (&lt;24 months; n = 20); DS2547 (25&#8211;47 months; n = 23); and DS48+ (&#8805;48 months; n = 21). These groups were compared to a recruit class (REC; 219 males, 34 females) in the WSTB, which comprised five tasks completed for time: 99-yard (90.53-m) obstacle course (99OC); 165-pound (75-kg) dummy drag; six-foot (1.83-m) chain link fence (CLF) and solid wall (SW) climb; and 500-yard (457.2-m) run (500R). A univariate analysis of covariance (ANCOVA) (controlling for sex and age) with Bonferroni post hoc determined significant between-group differences. DS48+ were slower in the 99OC compared to the REC (p = 0.007) and performed the CLF and SW slower than all groups (p &#8804; 0.012). DS24, DS2547, and DS48+ were all slower than REC in the 500R (p &#8804; 0.002). Physical training should be implemented to maintain fitness and job-specific task performance in deputy sheriffs working custody, especially considering the sedentary nature of this work

Challenges to managing quality of care in northern Queensland residential aged care facilities

Background: Senior management teams in residential aged care facilities (RACFs) face a range of challenges in providing quality health care services. With increasing attention directed at quality problems in Australian RACFs, there is an urgent need to better understand the experiences of this crucial cadre. This qualitative study sought to identify challenges from the perspective of current senior managers in residential aged care (RAC) organisations and map their influence on the quality of health care provided within. Methods: 20 semi-structured interviews were conducted with senior managers in 14 RACFs in northern Queensland, Australia. Thematic analysis was used, combining inductive identification of managerial challenges and a mapping exercise to locate these encounters against health system quality dimensions in the Australian National Health Performance Framework (NHPF). Results: Reported challenges to promoting and sustaining quality health care within RACFs included barriers to recruiting and retaining skilled staff, service constraints resulting from geographical isolation, limited access to quality fiscal resources, and a recent change to regulatory and administrative requirements. Identified challenges touch on all sub-dimensions of the NHPF. Conclusion: Several forces, many structural, currently challenge quality health care services in northern Queensland RACFs. Senior management teams come under substantial pressure and are developing short term solutions to protect quality in the face of often chronic and structural challenges. Alongside work to address macro-level issues, more work is needed to understand the personal and professional attributes of senior managers who are successful in positively influencing facility-level quality issues