Studies on Aromatic Cardo Copolymers

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Bactericidal mechanisms of nanoparticles and microbial defence strategies

Manufactured nanoparticles can be toxic to living organisms. This work aims to study the interaction of nanoparticles with bacteria as a model organism. The first objective was, to determine the mechanistic pathways of nanotoxicity with an emphasis on ions and oxidative stress as two key contributors and the second objective, was to investigate what mechanisms bacteria have developed as a strategy to protect themselves against nanotoxicity. The thesis further explores the role of environmental variables such as water chemistry, organic matter and other microorganisms, all of which can potentially change speciation of nanoparticles through their transformation into less toxic species. KEIO deletion mutants lacking genes encoding proteins which mediate resistance to oxidative stress and ionic toxicity were screened and found to be sensitive to both ionic silver and silver nanoparticles. A bioreporter to detect silver ions was constructed. This was found not to be induced by silver nanoparticles, yet showed reduced viability; this observation also indicates that besides ionic silver there are other toxicity pathways. E. coli strains capable of mediating resistance to oxidative stress by overexpression of certain proteins and bio reporters that could detect oxidative stress were constructed. The biosensor cells provide some but not too significant signals. Overexpression of proteins like superoxide dismutase and catalase reduces cell growth, hence, cell viability assays do not provide a realistic measure of protective impact, and thus this strategy is not suited to detect the nature of nanotoxicity. The protective role of extracellular polymeric substances (EPS) was studied by developing an engineered strain of E. coli that overproduces the EPS colanic acid, and use of mutant strains of Sinorhizobium meliloti, a free-living N2 fixing bacterium. Nanoparticle exposure studies reveal that overproduction of EPS mitigates silver nanotoxicity. EPS encapsulates the cells and leads to aggregation of nanoparticles, as shown by microscopy and dynamic light scattering. Furthermore, addition of xanthan, an EPS analogue also produces a similar effect. Lastly, x-ray absorption spectroscopy (XAS) of microcosms amended with silver and zinc oxide nanoparticles show rapid transformation of nanoparticles into corresponding oxides and sulphides. The microcosms show a significant presence of dissimilatory sulphate reducing bacteria (DSRB), and display only marginal change in bacterial community composition on exposure to nanoparticles. These findings suggest that nanomaterials will undergo changes in speciation dependent on the sediment chemistry and the metabolic activities of bacteria in the environment. This process will influence the impact of nanoparticles and the outcomes could be quite different from controlled in vitro exposure studies

Bridging the gap between clinicians' delivery and patients' experience of eating disorder diagnoses

The notion of diagnosis has been shown to have a profound influence within mental health practice with much attention focusing on the controversies and challenges surrounding the diagnostic classification of eating disorders. However, research focusing on how patients experience their eating disorder diagnosis is scarce. The purpose of this research, therefore, was to address this gap in the literature by exploring patients’ experiences of receiving a diagnosis of an eating disorder. Ten female patients were recruited from an adult community eating disorders service in the UK. All patients had received an eating disorder diagnosis and were interviewed using a semi-structured interview schedule. Transcribed interviews were qualitatively analysed using the principles of Interpretative Phenomenological Analysis (IPA). Four master themes emerged from the data: (1) Living with an unlabelled condition, (2) Perception of the patient-therapist relationship and interpersonal qualities, (3) Living with the diagnostic label, (4) A pathway to recovery. The findings provide a rich description on how participants experienced diagnosis. Patients’ experiences were both negative and positive whereby their experiences progressed from disbelief and rejection of the diagnosis to ideas of acceptance and recovery. Receiving and living with a diagnosis of an eating disorder has a significant impact on patients which should be considered throughout their assessment and treatment process. The need for compassionate care from professionals was an important component that was highlighted and recommendations were made in this regard. It is argued that increased awareness of patient experience will help clinicians to develop stronger therapeutic alliances and develop new clinical interventions

Microbial Reduction of Natural Fe(III) Minerals; Toward the Sustainable Production of Functional Magnetic Nanoparticles

The microbial synthesis of biominerals offers a potentially sustainable green solution for the production of a wide range of industrially relevant functional nanomaterials. Metal-reducing bacteria are of particular relevance, as they can enzymatically reduce a wide spectrum of high oxidation state metals and metalloids, forming cell-templated nanomagnets, catalysts, remediation agents, and quantum dots. Although these bioprocesses have been shown to be both scalable and tunable (with respect to particle size, reactivity, magnetic properties, and light emitting properties), they have yet to be taken up by industry. Here, we show that naturally abundant Fe(III) minerals are appropriate raw materials for the production of magnetic Fe(II)-bearing nanoparticles by the subsurface bacterium Geobacter sulfurreducens, and these bionanomaterials have the potential for remediation applications–here confirmed by the efficient reduction of toxic, mobile Cr(VI) to less toxic and soluble Cr(III). Detailed molecular-scale characterization of the bioreduced nanominerals, alongside life cycle assessments, and life cycle costings, confirm the efficient production of highly reactive and magnetic nanomaterials from waste materials. This adds further weight to the adoption of microbial technologies for sustainable, functional nanomaterials in a circular economy

Life cycle assessment of sustainable raw material acquisition for functional magnetite bionanoparticle production

Magnetite nanoparticles (MNPs) have several applications, including use in medical diagnostics, renewable energy production and waste remediation. However, the processes for MNP production from analytical-grade materials are resource intensive and can be environmentally damaging. This work for the first time examines the life cycle assessment (LCA) of four MNP production cases: (i) industrial MNP production system; (ii) a state-of-the-art MNP biosynthesis system; (iii) an optimal MNP biosynthesis system and (iv) an MNP biosynthesis system using raw materials sourced from wastewaters, in order to recommend a sustainable raw material acquisition pathway for MNP synthesis. The industrial production system was used as a benchmark to compare the LCA performances of the bio-based systems (cases ii-iv). A combination of appropriate life cycle impact assessment methods was employed to analyse environmental costs and benefits of the systems comprehensively. The LCA results revealed that the state-of-the-art MNP biosynthesis system, which utilises analytical grade ferric chloride and sodium hydroxide as raw materials, generated environmental costs rather than benefits compared to the industrial MNP production system. Nevertheless, decreases in environmental impacts by six-fold were achieved by reducing sodium hydroxide input from 11.28 to 1.55 in a mass ratio to MNPs and replacing ferric chloride with ferric sulphate (3.02 and 2.59, respectively, in a mass ratio to MNPs) in the optimal biosynthesis system. Thus, the potential adverse environmental impacts of MNP production via the biosynthesis system can be reduced by minimising sodium hydroxide and substituting ferric sulphate for ferric chloride. Moreover, considerable environmental benefits were exhibited in case (iv), where Fe(III) ions were sourced from metal-containing wastewaters and reduced to MNPs by electrons harvested from organic substrates. It was revealed that 14.4 kJ and 3.9 kJ of primary fossil resource savings could be achieved per g MNP and associated electricity recoveries from wastewaters, respectively. The significant environmental benefits exhibited by the wastewater-fed MNP biosynthesis system shows promise for the sustainable production of MNPs

”Työttömyyden sietämätön keveys” - Työttömyyden subjektiivinen kokemus Kymenlaaksossa irtisanotuilla paperityömiehillä

Opinnäytetyön tarkoitus on tutkia työttömyyden subjektiivista kokemusta Kymenlaaksossa työttömiksi jääneiden raskaan teollisuuden työntekijöiden parissa sekä heidän taloudellista toimeentuloaan. Opinnäytetyö on laadullinen tutkimus, jossa haastatellaan kahta pitkäaikaistytötöntä paperityöntekijää, jotka jäivät työttömiksi 2000-luvun raskaan teollisuuden alasajon johdosta Kymenlaakson alueella. Itse opinnäytetyö sisältää kaksi anonyymia henkilöhaastattelua, jotka pyrkivät kartoittamaan kyseisten pitkäaikaistyöttömien hyvinvointia. Haastatteluissa käsiteltiin haastateltavien irtisanomisprosessia, toimeentuloa, deprivaation subjektiivista kokemusta, arjenhallintaa sekä haastateltavien kokemuksia omasta työkyvystään