Temporal and spatial evolution of a waxing then waning catastrophic density current revealed by chemical mapping

We reconstruct the behavior of a catastrophic sustained radial pyroclastic density current as it waxed then waned during its brief lifespan. By subdividing the deposit into 8 time slices using a chemical tracer, we show that the sustained current initially was topographically restricted, but that its leading edge advanced in all directions, encroaching upon and gradually ascending hills. During peak flow the current reached its maximum extent and overtopped all topographic highs. After this, and while the current direction from source was maintained, the leading edge gradually retreated sourceward. High-resolution analysis of the depositional architecture reveals how the flow dynamics evolved and runout distance of the sustained density current rapidly increased then decreased, reflecting the dominant influence of changing mass flux, as demonstrated in numerical models but not previously distinguished in a natural deposit

Mechanisms of burst release from pH-responsive polymeric microparticles.

Microencapsulation of drugs into preformed polymers is commonly achieved through solvent evaporation techniques or spray drying. We compared these encapsulation methods in terms of controlled drug release properties of the prepared microparticles and investigated the underlying mechanisms responsible for the “burst release” effect. Using two different pH-responsive polymers with a dissolution threshold of pH 6 (Eudragit L100 and AQOAT AS-MG), hydrocortisone, a model hydrophobic drug, was incorporated into microparticles below and above its solubility within the polymer matrix. Although, spray drying is an attractive approach due to rapid particle production and relatively low solvent waste, the oil-in-oil microencapsulation method is superior in terms of controlled drug release properties from the microparticles. Slow solvent evaporation during the oil-in-oil emulsification process allows adequate time for drug and polymer redistribution in the microparticles and reduces uncontrolled drug burst release. Electron microscopy showed that this slower manufacturing procedure generated non-porous particles whereas thermal analysis and X-ray diffractometry showed that drug loading above the solubility limit of the drug in the polymer generated excess crystalline drug on the surface of the particles. Raman spectral mapping illustrated that drug was homogeneously distributed as a solid solution in the particles when loaded below saturation in the polymer with consequently minimal burst release

A study on information induced medication errors

The electronic health record (eHR) system has recently been considered one of the biggest advancements in healthcare services. A personally controlled electronic health record (PCEHR) system is proposed by the Australian government to make the health system more agile, secure, and sustainable. Although the PCEHR system claims the electronic health records can be controlled by the patients, healthcare professionals and database/system operators may assist in disclosing the patients’ eHRs for retaliation or other ill purposes. As the conventional methods for preserving the privacy of eHRs solely trust the system operators, these data are vulnerable to be exploited by the authorised personnel in an immoral/unethical way. Furthermore, issues such as the sheer number of eHRs, their sensitive nature, flexible access, and efficient user revocation have remained the most important challenges towards fine-grained, cryptographically enforced data access control. In this paper we propose a patient centric cloud-based PCEHR framework, which employs a homomorphic encryption technique in storing the eHRs. The proposed system ensures the control of both access and privacy of eHRs stored in the cloud database

Four activities to promote student engagement with referencing skills

Teaching academic writing skills in a way that engages students in deep learning is difficult and there is a risk of encouraging surface learning approaches. Moreover, linking the experience of the research process to understanding the provenance of research studies is difficult for students as they tend to experience research, referencing, citing, and related areas in disparate and unconnected ways. We report our initial experiences of designing a series of four mutually supportive tutorial activities that are based on the principles of scaffolding, social interaction, and experiential learning. The aim was to help students identify suitable research material that could be used as evidence in assignments and to promote their understanding of how evidence can be used effectively, through referencing, when writing reports and essays

Four activities to promote student engagement with referencing skills

Teaching academic writing skills in a way that engages students in deep learning is difficult and there is a risk of encouraging surface learning approaches. Moreover, linking the experience of the research process to understanding the provenance of research studies is difficult for students as they tend to experience research, referencing, citing, and related areas in disparate and unconnected ways. We report our initial experiences of designing a series of four mutually supportive tutorial activities that are based on the principles of scaffolding, social interaction, and experiential learning. The aim was to help students identify suitable research material that could be used as evidence in assignments and to promote their understanding of how evidence can be used effectively, through referencing, when writing reports and essays

Synthesis and self-assembly of linear and cyclic degradable graft copolymers

This thesis explores the use of ring-opening polymerisation (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerisation to prepare linear and cyclic graft copolymers with a polycarbonate backbone. The solution properties and self-assembly behaviour of these linear and cyclic graft copolymers with hydrophilic side arms is also described. Chapter 1 introduces the polymerisation techniques used in this thesis, namely ROP and RAFT, and provides a review of the self-assembly of polymers that possess a cyclic topology. In Chapter 2, the synthesis and ROP of a novel cyclic carbonate monomer bearing pendent norbornene functionality is described. Successful postpolymerisation modification of the norbornene functionality is demonstrated for a range of addition reactions; 1,3-dipolar cycloaddition, inverse electron demand Diels-Alder reaction and radical thiol-ene addition, and is also shown to provide access to multi-functional polycarbonates. Attempts to prepare graft copolymers via the grafting of thiol-terminated polymer chains to the norbornene-functional polycarbonate backbone are also described. Chapter 3 describes the optimised synthesis of linear graft copolymers via the ROP of a RAFT chain transfer agent (CTA)-functional cyclic carbonate monomer and subsequent RAFT polymerisation to grow polymer chains from the RAFT CTA sites located along the resulting polycarbonate backbone. This methodology was used to prepare a polycarbonate-g-poly(Nisopropylacrylamide) amphiphilic copolymer and its self-assembly to afford degradable, thermoresponsive particles is demonstrated. In Chapter 4, the optimised procedures developed in Chapter 3 for the preparation of linear graft copolymers are applied to the preparation of welldefined cyclic graft copolymers with a degradable cyclic polycarbonate backbone and a range of side arm compositions. Chapter 5 investigates the solution properties and self-assembly behaviour of linear and cyclic graft copolymers with hydrophilic poly(N-acryloylmorpholine) side arms and a hydrophobic polycarbonate backbone, prepared using the methodologies developed in Chapters 3 and 4. Chapter 6 provides a summary of the key findings of Chapters 2 – 5 and Chapter 7 provides the experimental methods of this thesis

MASE: A New Data--Reduction Pipeline for the Magellan Echellette Spectrograph

We introduce a data reduction package written in Interactive Data Language (IDL) for the Magellan Echellete Spectrograph (MAGE). MAGE is a medium-resolution (R ~4100), cross-dispersed, optical spectrograph, with coverage from ~3000-10000 Angstroms. The MAGE Spectral Extractor (MASE) incorporates the entire image reduction and calibration process, including bias subtraction, flat fielding, wavelength calibration, sky subtraction, object extraction and flux calibration of point sources. We include examples of the user interface and reduced spectra. We show that the wavelength calibration is sufficient to achieve ~5 km/s RMS accuracy and relative flux calibrations better than 10%. A light-weight version of the full reduction pipeline has been included for real-time source extraction and signal-to-noise estimation at the telescope.Comment: 10 pages (ApJ format), accepted PAS