Crystallographic and magnetic identification of secondary phase in orientated Bi5Fe0.5Co0.5Ti3O15 ceramics

Oxide materials which exhibit both ferroelectricity and ferromagnetism are of great interest for sensors and memory applications. Layered bismuth titanates with an Aurivillius structure, (BiFeO3)nBi4Ti3O12, can possess ferroelectric and ferromagnetic order parameters simultaneously. It has recently been demonstrated that one such example, Bi5Fe0.5Co0.5Ti3O15,where n = 1 with half the Fe3+ sites substituted by Co3+ ions, exhibits both ferroelectric and ferromagnetic properties at room temperature. Here we report the fabrication of highly-oriented polycrystalline ceramics of this material, prepared via molten salt synthesis and uniaxial pressing of high aspect ratio platelets. Electron backscatter images showed that there is a secondary phase within the ceramic matrix which is rich in cobalt and iron, hence this secondary phase could contribute in the main phase ferromagnetic property. The concentration of the secondary phase obtained from secondary electron microscopy is estimated at less than 2.5 %, below the detection limit of XRD. TEM was used to identify the crystallographic structure of the secondary phase, which was shown to be cobalt ferrite, CoFe2O4. It is inferred from the data that the resultant ferromagnetic response identified using VSM measurements was due to the presence of the minor secondary phase. The Remanent magnetization at room temperature was Mr ≈ 76 memu/g which dropped down to almost zero (Mr ≈ 0.8 memu/g) at 460 oC, far lower than the anticipated for CoFe2O4

First isolation of Brucella pinnipedialis and detection of Brucella antibodies from bearded seals Erignathus barbartus

Brucella species infecting marine mammals was first reported in 1994 and in the years since has been documented in various species of pinnipeds and cetaceans. While these reports have included species that inhabit Arctic waters, the few available studies on bearded seals Erignathus barbatus have failed to detect Brucella infection to date. We report the first isolation of Brucella pinnipedialis from a bearded seal. The isolate was recovered from the mesenteric lymph node of a bearded seal that stranded in Scotland and typed as ST24, a sequence type associated typically with pinnipeds. Furthermore, serological studies of free-ranging bearded seals in their native waters detected antibodies to Brucella in seals from the Chukchi Sea (1990-2011; 19%) and Svalbard (1995-2007; 8%), whereas no antibodies were detected in bearded seals from the Bering Sea or Bering Strait or from captive bearded seals

Microstructural characterisation of resistance artery remodelling in diabetes mellitus

Introduction: Microvascular remodelling is a symptom of cardiovascular disease. Despite the mechanical environment being recognized as a major contributor to the remodelling process, it is currently only understood in a rudimentary way. Objective: A morphological and mechanical evaluation of the resistance vasculature in health and diabetes mellitus. Methods: The cells and extracellular matrix of human subcutaneous resistance arteries from abdominal fat biopsies were imaged using two-photon fluorescence and second harmonic generation at varying transmural pressure. The results informed a two-layer mechanical model. Results: Diabetic resistance arteries reduced in wall area as pressure was increased. This was attributed to the presence of thick, straight collagen fibre bundles that braced the outer wall. The abnormal mechanical environment caused the internal elastic lamina and endothelial and vascular smooth muscle cell arrangements to twist. Conclusions: Our results suggest diabetic microvascular remodelling is likely to be stress-driven, comprising at least 2 stages: (1) Laying down of adventitial bracing fibres that limit outward distension, and (2) Deposition of additional collagen in the media, likely due to the significantly altered mechanical environment. This work represents a step towards elucidating the local stress environment of cells, which is crucial to build accurate models of mechanotransduction in disease

Forensic microbiology reveals that Neisseria animaloris infections in harbour porpoises follow traumatic injuries by grey seals

Neisseria animaloris is considered to be a commensal of the canine and feline oral cavities. It is able to cause systemic infections in animals as well as humans, usually after a biting trauma has occurred. We recovered N. animaloris from chronically inflamed bite wounds on pectoral fins and tailstocks, from lungs and other internal organs of eight harbour porpoises. Gross and histopathological evidence suggest that fatal disseminated N. animaloris infections had occurred due to traumatic injury from grey seals. We therefore conclude that these porpoises survived a grey seal predatory attack, with the bite lesions representing the subsequent portal of entry for bacteria to infect the animals causing abscesses in multiple tissues, and eventually death. We demonstrate that forensic microbiology provides a useful tool for linking a perpetrator to its victim. Moreover, N. animaloris should be added to the list of potential zoonotic bacteria following interactions with seals, as the finding of systemic transfer to the lungs and other tissues of the harbour porpoises may suggest a potential to do likewise in humans

Vernacular mapping : affect, virtuality, performance

In diagramming the recent, global proliferation in quotidian cartographic technologies and practices, this thesis is concerned with the re-imagining of durable geographic motifs and refrains; those of maps and mappings. Conceptually, the thesis works to explore and interrogate the underplayed non-representational registers of cartography. Specifically, this entails unsettling the assumed ontological security of maps as representational artefacts, at the same time accentuating their affective and virtual vectors through an attentiveness to their spatial emergence and performance. In doing so, maps are rendered here not as mimetic, static grids of existence, but as intensive performances, productive of an unqualified geographic and political potential; that is to say, spaces of the virtual. Empirically, these conceptual concerns are worked through a series of fieldwork traces that animate and narrate a number of quite distinct yet resonant cartographic performances; namely geographic encounters with a counter-cartography group in North Carolina; a digital, open-source mapping organisation in both the UK and Peru and finally with two examples of an institutional cartography: Google and Ordnance Survey. Through these mappings, these fieldwork traces, what the thesis works towards is a micropolitical diagramming of contemporary cartographic practices, a diagramming that complicates deliberately the representational certitude of maps, but moreover, one that affirms the (im)material, anticipatory and minor geopolitics of mapping; a mapping of and for the everyday; a mapping of and for the vernacular.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Over-flowing with issues? Following the political trajectories of flooding

The paper is based on a research project that engaged with and intervened in flood risk management in national policy and in two localities. Building on recent work in STS, we develop a framework for political analysis that complements existing understandings of environmental governance by focusing on the materiality of an issue and the ways in which it is articulated through various sites, shifting between different political modalities (its political trajectory). Each modality represents a different way in which an issue is framed such that it is opened to questioning and contestation, or subject to closure and containment. We conclude that differing understandings of what makes an environmental issue political mean that researchers need to pay close attention to how their own work is political and to different meanings and constitutions of ‘the public’, as well as looking for more ways of engaging with the politics of environmental issues in different modalities