Kooka(borough)

The Kookaburra as iconic Australian bird is represented in this photo-series exploring photomention principles, of photographing the decisive moment but rather than documenting it fully, applying documention theory of glancing or incorporating in passing through. This follows on in the vein of Group f/64 who through the lowest f stop sought to achieve detail and specificity that was beyond realist painting\u27s capabilities. Of which, Henri Cartier-Bresson wrote: “In photography, there is a new kind of plasticity, the product of instantaneous lines made by movements of the subject. We work in unison with movement as though it were a presentiment of the way in which life itself unfolds. But inside movement there is one moment at which the elements in motion are in balance. Photography must seize upon this moment and hold immobile the equilibrium of it.” This seizing of the frozen moment at which movement/moment are aligned towards a new geometry of spontaneity forms the basis of my aesthetic towards realist iconic immediacy - of phot(icon)ography. A borough is a subdivision of a city, for example London or New York - where a borough is administered with limited powers given to it by the city\u27s local government. In a city such as Wagga Wagga, we relegate nature to the borough of an administered domain, wherein nature itself has been provided limited controls over its own agency. This photograph series, in this case Kooka(borough) clearly, decisively aims to restore nature to its primacy. The work continues its enquiry into the decisive moment aesthetic, and of naturalism and observed opportunity. It is not a photoshopped or otherwise altered or mediated photograph in any manner. A kookaburra alighted on the main flag-pole in the Historic Gardens in Wagga Wagga, and the Australian flag fluttered. The occurrence of our national symbols being naturally juxtaposed in this manner would be rare indeed; perhaps three million to one - this is a straight photograph of just such an instant where the real is beyond the range of normalcy. The photograph was shot on a hand-held Canon A480, rather than Cartier-Bresson\u27s preferred 35mm camera. My photographic practice continues to explore these principles of straight photography, and autojournalism, to investigate observed iconic moments

Investigating the viability of sulfur polymers for the fabrication of photoactive, antimicrobial, water repellent coatings

Elemental sulfur (S8), a by-product of the petroleum refining industries, possesses many favourable properties including photocatalytic activity and antibacterial activity, in addition to being intrinsically hydrophobic. Despite this, there is a relative lack of research employing elemental sulfur and/or sulfur copolymers within superhydrophobic materials design. In this work, we present the use of sulfur copolymers to produce superhydrophobic materials with advanced functionalities. Using inverse vulcanization and the use of a natural organic crosslinker, perillyl alcohol (PER), stable S8-PER copolymers were synthesised and later combined with silica (SiO2) nanoparticles, to achieve highly water repellent composites that displayed both antimicrobial and photocatalytic properties, in the absence of carcinogenic and/or expensive materials. Here, we investigated the antibacterial performance of coatings against the Staphylococcus aureus bacterial strain, where coatings displayed great promise for use in antifouling applications, as they were found to limit surface adhesion by more than 99%, when compared to uncoated glass samples. Furthermore, UV dye degradation tests were performed, utilizing the commercially available dye resazurin, and it was shown that coatings had the potential to simultaneously exhibit surface hydrophobicity and photoactivity, demonstrating a great advancement in the field of superhydrophobic materials

Activated Defense Systems in Marine Macroalgae: Evidence for an Ecological Role for DMSP Cleavage

Activated defenses against herbivores and predators are defenses whereby a precursor compound is stored in an inactive or mildly active form. Upon damage to the prey, the precursor is enzymatically converted to a more potent toxin or feeding deterrent. In marine systems, activated defenses are only known to exist in a few species of tropical macroalgae. In this study, we examined an activated defense system in temperate marine macroalgae in which the osmolyte dimethylsulfo- niopropionate (DMSP) is converted to acrylic acid or acrylate, depending upon the pH, and dimethyl sulfide (DMS) by the enzyme DMSP lyase upon damage to the alga. We surveyed 39 species of red, green, and brown algae from the Washington and Oregon coasts, and found high concentrations of DMSP in the chlorophytes Acrosiphonia coalita, Codium fragile, Enteromorpha intestinaUs, E. linza, Ulva californica, U. fenestrata, and U. taeniata, and in the rhodophyte Polysiphonia hendryi. Concentrations of DMSP ranged from 0.04 % of the alga\u27s fresh mass (FM) to 1.8% FM. We found significant DMSP lyase activity in 1 green alga, U. fenestrata, and 1 red alga, P. hendryi, with DMSP cleavage rates approaching 300 mmol kg-1 FM mi-1. Loss of DMSP and the production of DMS when the tissues of U. californica and P. hendryi were crushed suggested that physical damage results in DMSP cleavage. In laboratory feeding preference experiments, acryhc acid deterred feeding by the sea urchin Strongylocentrotus droebachiensis at concentrations of 0.1 to 2% FM and by S. purpura- tus at 0.25 to 2% FM, while the precursor DMSP functioned as a feeding attractant to both sea urchins. In contrast, feeding by the isopod Idotea wosnesenskii was not deterred by acrylic acid even at concentrations as high as 8% FM. Our data suggest that DMSP may function as a precursor in an activated defense system in diverse species of temperate macroalgae and may possibly contribute to the widespread success of the Ulvophyceae. This chemical system is also found in unicellular phytoplankton, and presents an opportunity to compare and contrast the ecological role of chemical defense among micro- and macroorganisms

Exposure to diesel exhaust particles increases susceptibility to invasive pneumococcal disease.

BACKGROUND: The World Health Organization estimates that air pollution is responsible for 7 million deaths per annum, with 7% of these attributable to pneumonia. Many of these fatalities have been linked to exposure to high levels of airborne particulates, such as diesel exhaust particles (DEPs). OBJECTIVES: We sought to determine whether exposure to DEPs could promote the progression of asymptomatic nasopharyngeal carriage of Streptococcus pneumoniae to invasive pneumococcal disease. METHODS: We used mouse models and in vitro assays to provide a mechanistic understanding of the link between DEP exposure and pneumococcal disease risk, and we confirmed our findings by using induced sputum macrophages isolated from healthy human volunteers. RESULTS: We demonstrate that inhaled exposure to DEPs disrupts asymptomatic nasopharyngeal carriage of S pneumoniae in mice, leading to dissemination to lungs and blood. Pneumococci are transported from the nasopharynx to the lungs following exposure to DEPs, leading to increased proinflammatory cytokine production, reduced phagocytic function of alveolar macrophages, and consequently, increased pneumococcal loads within the lungs and translocation into blood. These findings were confirmed by using DEP-exposed induced sputum macrophages isolated from healthy volunteers, demonstrating that impaired innate immune mechanisms following DEP exposure are also at play in humans. CONCLUSION: Lung inhaled DEPs increase susceptibility to pneumococcal disease by leading to loss of immunological control of pneumococcal colonisation, increased inflammation, tissue damage, and systemic bacterial dissemination

Pneumococcal Colonization and Virulence Factors Identified Via Experimental Evolution in Infection Models

Streptococcus pneumoniae is a commensal of the human nasopharynx and a major cause of respiratory and invasive disease. We examined adaptation and evolution of pneumococcus, within nasopharynx and lungs, in an experimental system where the selective pressures associated with transmission were removed. This was achieved by serial passage of pneumococci, separately, in mouse models of nasopharyngeal carriage or pneumonia. Passaged pneumococci became more effective colonizers of the respiratory tract and we observed several examples of potential parallel evolution. The cell wall-modifying glycosyltransferase LafA was under strong selection during lung passage, whereas the surface expressed pneumococcal vaccine antigen gene pvaA and the glycerol-3-phosphate dehydrogenase gene gpsA were frequent targets of mutation in nasopharynx-passaged pneumococci. These mutations were not identified in pneumococci that were separately evolved by serial passage on laboratory agar. We focused on gpsA, in which the same single nucleotide polymorphism arose in two independently evolved nasopharynx-passaged lineages. We describe a new role for this gene in nasopharyngeal carriage and show that the identified single nucleotide change confers resistance to oxidative stress and enhanced nasopharyngeal colonization potential. We demonstrate that polymorphisms in gpsA arise and are retained during human colonization. These findings highlight how within-host environmental conditions can determine trajectories of bacterial evolution. Relative invasiveness or attack rate of pneumococcal lineages may be defined by genes that make niche-specific contributions to bacterial fitness. Experimental evolution in animal infection models is a powerful tool to investigate the relative roles played by pathogen virulence and colonization factors within different host niches

Intestinal helminth co-infection is an unrecognised risk factor for increased pneumococcal carriage density and invasive disease.

Infection with Streptococcus pneumoniae is the leading cause of death in children and burden of disease is greatest where helminth infections are also common. We investigated the impact of intestinal helminth co-infection on pneumococcal carriage; a risk factor for invasive disease. We used a mouse co-infection model and clinical data to assess the impact of co-infection on carriage density. Co-infection in mice was associated with increased pneumococcal carriage density and dissemination into lungs. Helminth-infected children also exhibited increased carriage density as compared to uninfected children. Anthelmintic treatment may be a cost-effective method of reducing pneumococcal disease burden in lower-income countries

Exploring inverse vulcanisation mechanisms from the perspective of dark sulfur

The build-up of elemental sulfur waste poses problems such that only the advancement of process and product design might act as a solution. Inverse vulcanisation, a process for the generation of high sulfur content polymeric materials may be one such resolution. However, a complete understanding of how these materials form is yet to be fully agreed in this emerging field. Herein is an investigation into the understanding of ‘dark sulfur’ – amorphous, unreacted sulfur, not incorporated into the polymer backbone – in an attempt to understand further the formation mechanisms behind inverse vulcanisation. This research posits theories regarding polymer formation, thermal rearrangement, and the actions of OH to control the degree of product crosslinking, in relation to the quantity of sulfur unreacted into the polymer structure. The detriments and benefits of this dark sulfur in relation to application and general usage are also investigated, showing that a high content of dark sulfur may encourage planktonic bactericidal activity, while also promoting safety considerations from generated species such as hydrogen sulfide and carbon disulfide, concluded as components of this dark sulfur

Macrophage-derived human resistin is induced in multiple helminth infections and promotes inflammatory monocytes and increased parasite burden.

Parasitic helminth infections can be associated with lifelong morbidity such as immune-mediated organ failure. A better understanding of the host immune response to helminths could provide new avenues to promote parasite clearance and/or alleviate infection-associated morbidity. Murine resistin-like molecules (RELM) exhibit pleiotropic functions following helminth infection including modulating the host immune response; however, the relevance of human RELM proteins in helminth infection is unknown. To examine the function of human resistin (hResistin), we utilized transgenic mice expressing the human resistin gene (hRetnTg+). Following infection with the helminth Nippostrongylus brasiliensis (Nb), hResistin expression was significantly upregulated in infected tissue. Compared to control hRetnTg- mice, hRetnTg+ mice suffered from exacerbated Nb-induced inflammation characterized by weight loss and increased infiltration of inflammatory monocytes in the lung, along with elevated Nb egg burdens and delayed parasite expulsion. Genome-wide transcriptional profiling of the infected tissue revealed that hResistin promoted expression of proinflammatory cytokines and genes downstream of toll-like receptor signaling. Moreover, hResistin preferentially bound lung monocytes, and exogenous treatment of mice with recombinant hResistin promoted monocyte recruitment and proinflammatory cytokine expression. In human studies, increased serum resistin was associated with higher parasite load in individuals infected with soil-transmitted helminths or filarial nematode Wuchereria bancrofti, and was positively correlated with proinflammatory cytokines. Together, these studies identify human resistin as a detrimental factor induced by multiple helminth infections, where it promotes proinflammatory cytokines and impedes parasite clearance. Targeting the resistin/proinflammatory cytokine immune axis may provide new diagnostic or treatment strategies for helminth infection and associated immune-mediated pathology

Increasing dominance of large lianas in Amazonian forests

Ecological orthodoxy suggests that old-growth forests should be close to dynamic equilibrium, but this view has been challenged by recent findings that neotropical forests are accumulating carbon and biomass, possibly in response to the increasing atmospheric concentrations of carbon dioxide. However, it is unclear whether the recent increase in tree biomass has been accompanied by a shift in community composition. Such changes could reduce or enhance the carbon storage potential of old-growth forests in the long term. Here we show that non-fragmented Amazon forests are experiencing a concerted increase in the density, basal area and mean size of woody climbing plants (lianas). Over the last two decades of the twentieth century the dominance of large lianas relative to trees has increased by 1.7–4.6% a year. Lianas enhance tree mortality and suppress tree growth, so their rapid increase implies that the tropical terrestrial carbon sink may shut down sooner than current models suggest. Predictions of future tropical carbon fluxes will need to account for the changing composition and dynamics of supposedly undisturbed forests