The environmental, microbiological and technological aspects of selenium is explored with the aim of assessing and identifying microorganisms capable of interacting with Se in the environment and forming functional 'bionanomaterials'. To determine the natural microbial response to high selenium concentrations, and to understand the role soil microorganisms play in transforming Se, a field site in Co. Meath, Ireland, was identified and sampled to determine the Se contents. Detailed examination of the soil profile showed toxic levels of Se up to 156ppm. The highest Se concentrations correlated with elevated concentrations of higher plant matter, inferring a phytoconcentration mechanism for Se within a post glacial fen, and Se was identified as a reduced organic species. Microcosm experiments were established to test whether the soil microbial community displayed increased resistance to Se. These revealed the Se present in the soil was recalcitrant to microbial degradation and Se(VI) enriched experiments were noted to cause drastic alterations in community structure, indicating elevated Se resistance was not widespread throughout the community. Despite this, amended Se(VI) was rapidly reduced to Se(0), as determined by XAS. Selenium, and the group 16 element tellurium, also display physico-chemical properties that make them ideal for a range of industrial, chemical and technological applications, including sequestration of hazardous wastes and as metal chalcogenide semiconducting 'quantum dots'. Se(0) and Te(0) bionanomaterials formed by 'resting cell' cultures of the model environmental isolate Geobacter sulfurreducens, despite low MIC values, were characterised and subsequently applied to the sequestration of Hg(0)v derived from Hg historically used to preserve herbarium specimens. This showed that the Hg can be sequestered by the Se(0) bionanoparticles in the form of HgSe and demonstrated increased stability over abiotic counterparts. Finally, the bacteria G. sulfurreducens, Shewanella oneidensis and Veillonella atypica were compared for Se(IV) reducing capabilities, and V. atypica was shown to be adept at the production of significant quantities of Se(II-) utilising the electron shuttle AQDS. Biogenic Se(II-) compared favourably with abiotic Se(II-) solutions in the formation of metal selenide quantum dots, displaying increased particle growth control as shown via a novel, time resolved XAS technique. Bacterial polymeric substances are inferred in controlling Se(II-) precursor stability. This research shows that bacteria represent an alternative, facile, 'green' synthetic method for the production of next-generation technological nanomaterials.

The biological activity or availability or feedstuff selenium was determined by comparing the effectiveness of the feedstuff with that of dietary sodium selenite in preventing the incidence of exudative diathesis in the chick. The available selenium in ten wheat samples varied from 62 to 178 percent with a mean of 105 percent. The selenium availability in rapeseed meal ranged from 27 to 89 percent with a mean of 61 percent. Selenium metabolism in the chick was investigated by adding graded levels of sodium selenite to the basal selenium deficient diet and comparing the dietary selenium concentration to the selenium concentration in the tissues (l.e. Blood, liver, kidney, and muscle of the chicks). The selenium content in the tissues examined increased proportionately to an increase in dietary selenium supplementation from 0 to 0.2 ppm. Blood and liver selenium concentration remain relatively constant (a slightly increasing plateau) from 0.2 to 1.0 ppm of dietary selenium. Above 1.0 ppm dietary selenium, blood and liver selenium levels increase steadily. These results show that either blood or liver selenium levels represent the selenium status of the bird. A similar response in tissue selenium levels of the chick was observed when selenium was supplied either as sodium selenite Or a feedstuff (brewers yeast). Furthermore, selenium levels birds fed wheat diets were similar to those fed equivalent selenium (sodium selenite) supplied in the basal diet. / Land and Food Systems, Faculty of / Graduate

A series of three experiments were carried out in order to demonstrate an interaction between molybdenum and selenium in broilers. Trail I investigated the interaction of selenium (0, 0.2, 0.4, and 0.8 ppm) with various toxic and subtoxic dietary levels of molybdenum (0, 0.5, 100, and 330 ppm), supplemented to a wheat based diet to broilers from one to four weeks of age. Results indicated that at 300 ppm molybdenum, increasing selenium levels resulted in progressive decline in weight gain, compared to a non-significant decline across these selenium levels when no molybdenum was supplemented. At these levels of molybdenum, selenium appeared to be acting antagonistically with molybdenum. At lower molybdenum levels, selenium exerted no apparent effects on weight gain. Selenium at toxic levels responded different from selenium at subtoxic dietary levels over molybdenum levels. Trial II, used 480 broiler chicks, assigned in a randomized block (RB) experimental design and 12 treatment combinations of selenium and molybdenum. Although the overall interaction effect was non-significant for weeks 1 to 4 inclusive, there were some definite interaction trends. Results indicated that at either basal or 3 ppm Se over basal 100, 200, or 300 ppm Mo, a non-significant difference in weight gain and feed consumption occurred. Selenium and molybdenum appeared to be interacting reciprocally. At 6 ppm dietary supplementation of selenium, however, combining increasing levels of molybdenum appeared to result in an independent toxic effect on weight gain which was additive for the two mineral toxicities, and not interactive. Using 480 broilers chicks assigned to a 3 x 4x3x3 multifactorial arrangement of 12 treatments an experiment was performed to investigate the effect on weight gain and feed consumption upon feeding toxic levels of molybdenum and selenium. Selenium levies ranged from basal, to 6, 12, and 18 ppm and molybdenum levels from basal, 400, and 800 ppm. Treatments were arranged in a RB experimental design. Results indicated that combining toxic dietary levels of selenium and molybdenum resulted in a measurable interaction in birds based on weight gain to feed consumption from one to four weeks of the experimental period. As the toxic dietary levels of selenium increased from basal to 6, 12, and 18 ppm the adverse effect of molybdenum at basal, 400 and 800 ppm became progressively reduced. At 18 ppm selenium, weight gain and feed consumption were the same irrespective of whether basal, 400, 800 ppm Mo was supplemented to the diet. The presence of toxic levels of selenium appeared to either reduce toxicity of molybdenum, or induce an increased tolerance for increasingly toxic levels of molybdenum. The nature of the interaction between selenium and molybdenum is discussed. / Land and Food Systems, Faculty of / Graduate

The elderly social care IT company Phoniro is developing solutions for deploying software using docker technologies. To secure quality in their deploy pipelines Phoniro would like to do automatic selenium testing within Docker containers. The project should set the framework and required technical solution to enable this and also run some basic test including suitable reporting on test success. This is a concept that is new to Phoniro that would allow them, if proven, to automate testing in a safe environment, and pushing their web applications to deployment faster. The purpose is to prove this concept by creating a framework that will easily let the user run web applications inside a Docker container. Then run this framework inside of a pipeline to see the testing capabilities. The user is supposed to be able to do this without any previous knowledge of how docker works. We have developed a framework in Python that enables the user to build and run their web application inside a docker container. We built a pipeline and connected it to the repository with the source code for the web application. The framework is run inside the pipeline to start the container, followed by simple selenium tests that we created to test the concept. We have proven the concept to run and test web applications in docker containers inside of pipelines to work. It is possible connect a web application in development to a repository, connect it to a pipeline and have it automatically test the application every time a change is made to the source code. By designing proper selenium tests the pipeline can save a lot of time and effort that is otherwise spent on manual testing

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19515号 / 理博第4175号 / 新制||理||1599(附属図書館) / 32551 / 京都大学大学院理学研究科化学専攻 / (主査)教授 丸岡 啓二, 教授 大須賀 篤弘, 教授 依光 英樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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