Dissertations / Theses on the topic 'Immobilisation'
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1
Brocklebank, Simon Pearson. "Rational immobilisation of enzymes : immobilisation of transketolase for carbon-carbon bond synthesis." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322288.
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Rossell, Jacqueline. "Protein immobilisation for AFM." Thesis, University of Nottingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404144.
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Coote, Alexander Stuart. "Polyurethanes for enzyme immobilisation." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47386.
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Hulak, Deschamps Isabelle. "Immobilisation d'anticorps sur polymères fonctionnalisés." Paris 13, 1990. http://www.theses.fr/1990PA132001.
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Afin d'améliorer les performances de trousses de dosages biologiques, basées sur des méthodes radioimmunométriques, des immunophases constituées de polypropylène ont été modifiées par voie chimique et par divers traitements par plasma froid. Des anticorps spécifiques peuvent être couples à ces phases solides ainsi modifiées. En effet, les trousses actuellement commercialisées sont obtenues par adsorption simple des anticorps à la surface des phases polymères. Le but de ce travail est donc de créer des fonctions chimiques modifiables afin d'accroitre les possibilités d'interactions spécifiques entre le support polymère et l'anticorps. Le principe de ces dosages immunométriques est base sur la formation d'un complexe mixte anticorps immobilise, antigène à doser, anticorps marque permettant le dosage. Il est donc souhaitable de réaliser l'immobilisation du premier anticorps par son fragment cristallisable FC afin de laisser libre sa partie active. Pour cela deux voies d'approches ont été étudiées. D'une part, la fixation des anticorps a été réalisée sur des surfaces activées en utilisant des agents de couplage afin d'obtenir une fixation covalente à la surface du polymère. D'autre part, ces anticorps ont été adsorbes par l'intermédiaire du fragment FC sur des surfaces rendues plus hydrophobes. En outre, les modifications chimiques et physico-chimiques réalisées permettent de modifier de façon notable les propriétés de surface du matériau. Cela nous a conduits à déterminer l'influence des caractéristiques de surface sur les mécanismes d'interactions conduisant à l'immobilisation des anticorps
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Oloo, Fiona Angela. "The immobilisation of enzymes on colloidal liquid aphrons (CLAs) : stability, immobilisation parameters and protein structural conformation." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412714.
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Wolowacz, Sorrel Elizabeth. "Novel immobilisation techniques for amperometric biosensors." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319586.
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El-Kholy, Amany Osama Amin. "Immobilisation and labelling chemistries of DNA." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339190.
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Green, Christopher A. "Covalent immobilisation of Langmuir-Blodgett films." Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386420.
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Mahmood, Nadia. "Novel immobilisation matrices for amperometric biosensors." Thesis, University of Huddersfield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368306.
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Dickson, Catherine Louise. "Immobilisation of actinide simulants in cement." Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300954.
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The current UK strategy for radioactive waste management is to permanently store the waste in an underground repository. Final disposal of the radwaste may then be preceded by chemical conditioning and physical encapsulation. The objective of this work was to determine the extent of actinide immobilisation in cement. Since actinides are hazardous and costly to study directly, a chemical analogue approach to studying actinide immobilisation was adopted. Th(IV), Ce(III, IV) and Eu(III) were chosen as actinide simulants and their suitability assessed by a critical review of the literature. Ca(OH)2 and C-S-H dominate the observed chemical properties of the aqueous phase in cement. As they are of such importance, it was these cement components which were used to investigate the reaction of the simulant elements with cement. The phases found to be predicted were ThO2, ThSiO4, Eu(OH)3, Ca2Eu8(SiO4)6O2, CeO2, CeSiO4 and Ca2(SiO4)6O2. CeSiO4 and Ca2Ce8(SiO4)O2 are newly reported phases, produced by hydrothermal synthesis. Rietveld refinement confirmed CeSiO4 to have the zircon structure, with space group 141/amd and cell parameters a = 6.9564(3) A, c = 6.1953 (4) A. Ca2Ce8(SiO4)6O2 exhibits the apatite structure, with space group P63/m and cell parameters a = 9.4343(3) a, c = 6.8885(4) A. Preliminary solubility studies were carried out on all of the solubility-limiting phases. Phase impurity, poor crystallinity and incongruent solubility of phases hindered the generation of solubility product data. Nevertheless, these phases have naturally occurring analogues which are known to be environmentally stable and have low solubilities. On the basis of the experimental results obtained, it may be concluded that cement has the potential to be a very effective immobilisation matrix for actinide elements. Recommendations for future experiments using active elements are discussed.
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Caruana, Daren Joseph. "Electrochemical immobilisation of enzymes on microelectrodes." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240238.
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Amourache, Leïla. "Purification et immobilisation de la chymosine." Compiègne, 1986. http://www.theses.fr/1986COMPI217.
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La chromatographie d'affinité utilisant un ligand biospécifique (pepstatine couplée à l'agarose) pour la purification de la chymosine permet l'obtention d'un rendement en activité de 60 % et un facteur de purification de 6, à partir d'un extrait brut. Cependant, le ligand acide aminé histidine couplé au Sepharose 4B et à la silice, a donné de meilleurs résultats, on obtient respectivement après purification de la chymosine, à partir d'un extrait brut : des rendements en activité de 330 %, 55 % ; et des facteurs de purification de 26 et 9. Le L-histidyl-silice présente des résultats peu satisfaisants par rapport au support L-histidyl- Sepharose 4B. Une optimisation des conditions d'utilisation du gel histidyl-silice serait souhaitable afin d'utiliser ce dernier en HPLC. La purification d'enzyme d'origine microbienne sur gel de L- histidyl-Sepharose permettrait de connaitre l'efficacité de ce gel pour ce type d'enzyme. Notre étude d'immobilisation de la chymosine sur un support nylon nous amène à considérer, que le choix du nylon offre l'avantage d'une mise en œuvre aisément applicable en industrie alimentaire, toutefois l'activité résiduelle reste encore faible notamment lors de l'emploi du glutaraldéhyde. L'activité résiduelle est considérablement améliorée par la BSA et le NaC1 ajoutés au milieu en fin de réaction et aussi lors de l'utilisation de l'agent covalent carbodiimide. Une application industrielle de la chymosine immobilisée nécessiterait un travail complémentaire : 1 - Neutraliser les groupements du support amine et carboxyl restant disponibles après immobilisation par la liaison covalente. Ceux-ci sont la cause d'une adsorption du substrat non désiré. 2- Approfondir la réalité des liaisons qui s'établissent entre l'enzyme et le support. 3 - Obtenir une enzyme très stableAffinity chromatography using pepstatine agarose for crude chymosine purification a 60 % yield with a 6 fold increase in specific activity. On the other hand, L-histidine coupled Sepharose 4B and silica gave better results with 33 % and 55 % yields and 26 and 9 fold purifications, respectively. The silica support, as seen the above results, gives less satisfying results when compound with hystidyl-sepharose. It would be necessary to optimise the end conditions before applying this technique for chymosine purification by HPLAC. Also, studies using chymosine of microbial origin would enable as to evaluate the efficiency of the gel for this sat of enzyme. After studies on the immobilization of chymosine we consider that the choice of nylon as an immobilization support would be advantageous for the food industry, the usidial activity, however remain low especially when glutaraldehyde is used. The use of BSA and NaC1 in the medium during storage increases the residual activity considerably. The use of carbodiimide equally gives better results. The industrial application of immobilized chymosine would require the following complementary studies : the neutralizations of free amine and carboxyl groups on the nylon surface after the immobilization ; to pursue an in-dyth study into the sort of bond existing between enzyme and the nylon support ; to procure a highly stable enzyme
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Richards, Emma. "Immobilisation of polyazamacrocycles into porous materials." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/8513/.
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The synthesis and characterisation of functionalised polyazamacrocycles and their subsequent immobilisation into porous materials were investigated and reported in this thesis. The incorporation of polyazamacrocycles into porous materials offers the potential to enhance their biomimetic and environmental properties with tuneable microenvironments around the macrocycles. Nine polyazamacrocycles have been synthesised that are functionalised with vinyl, pyridyl, carboxylate and iodide pendant arms in order to immobilise them into porous materials. Of these macrocycles nine metal complexes were successfully synthesised and their crystal structures are discussed. The most interesting of these metal complexes are complex 2, a cyclam based metal complex and complex 7, a [12]aneN3 based metal complex which both have coordinated water molecules and therefore are activated for hydrolase activity. Polyazamacrocycles have successfully been immobilised into organic cross-linked polymers using polar and non-polar cross-linkers and a systematic investigation has taken place in order to determine the effects of the nature and amount of porogen and the concentration of macrocycle within the polymer on the porous properties of the polymer. These effects include BET surface area, shape and size distributions of pores, and CO2 uptake capacities. The effect of incorporation of metal complexes and metal ions is also discussed. It was found that with non-polar based polymers, BET surface areas were find to be higher when non-polar porogens were employed and decrease with increasing polarity of the porogen. However, the nature of the macrocycle also plays an important role in the porosity of the resulting polymers. Zinc and copper metal organic frameworks containing cyclam based macrocycles with pyridyl pendent arms have been synthesised with 2D layered structures. The crystal structures reveal that triflate and hexafluorophosphate counterions play an important role in stabilisation of the framework but with the disadvantage of blocking possible porosity.
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Amourache, Leïla. "Purification et immobilisation de la chymosine." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595446p.
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Mayzan, Mohd Zul Hilmi. "Graphite immobilisation in glass composite materials." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/10051/.
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Irradiated graphite is a problematic nuclear waste stream and currently raises significant concern worldwide in identifying its long-term disposal route. This thesis describes the use of glass materials for the immobilisation of irradiated graphite prepared by microwave, conventional and sparks plasma sintering methods. Several potential glass compositions namely iron phosphate, aluminoborosilicate, calcium aluminosilicate, alkali borosilicate and obsidian were considered for the immobilisation of various loadings of graphite simulating irradiated graphite. The properties of the samples produced using different processing methods are compared selectively. An investigation of microwave processing using an iron phosphate glass composition revealed that full reaction of the raw materials and formation of a glass melt occurs with consequent removal of porosity at 8 minutes microwave processing. When graphite is present, iron phosphate crystalline phases are formed with much higher levels of residual porosity of up to 43 % than in the samples prepared using conventional sintering under argon. It is found that graphite reacts with the microwave field when in powder form but this reaction is minimised when the graphite is incorporated into a pellet, and that the graphite also impedes sintering of the glass. Mössbauer spectroscopy indicates that reduction of iron occurs with concomitant graphite oxidation. The production of graphite-glass samples using various powdered glass compositions by conventional sintering method still resulted in high porosity with an average of 6-17 % for graphite loadings of 20-25 wt%. Due to the use of pre-made glasses and controlled sintering parameters, the loss of graphite from the total mass is reduced compared to the microwaved samples; the average mass loss is < 0.8 %. The complication of iron oxidation and reduction is present in all the iron containing base glasses considered and this increases the total porosity of the graphite-glass samples. It is concluded that the presence of iron in the raw materials or base glasses as an encapsulation media for the immobilisation of the irradiated graphite waste is not advisable. The production of glass and graphite-glass samples based calcium aluminosilicate composition by spark plasma sintering method is found highly suitable for the immobilisation of irradiated graphite wastes. The advantages of the method includes short processing time i.e. < 40 minutes, improved sintering transport mechanisms, limited graphite oxidation, low porosity (1-4 %) and acceptable tensile strength (2-7 MPa). The most promising samples prepared using spark plasma sintering method were loaded with 30-50 wt% graphite.
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Disley, Darren-Matthew. "Immobilisation of the biological component of immunosensors." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389817.
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Harvey, E. J. "Actinide immobilisation in zirconate and titanate ceramics." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603819.
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Pyrochlores (A=2B2O7, Fd3m) have been proposed as candidate phases for the immobilisation of actinides from high level nuclear waste. They may form part of a multi-barrier approach to final waste disposition in an underground repository. Titanate and zirconate pyrochlores are particularly interesting; titanates show high chemical durability, whilst some zirconate pyrochlores display very high resistance to structural damage by radiation. To fully evaluate the likely performance of a pyrochlore-based waste-form, a comprehensive understanding of its structure and behaviour must be developed. Related phases, which might exsolve, must also be characterised, to test whether their presence will have a deleterious effect. Various zirconate and titanate oxides including (La1-xNdx)2Zr2O7, Nd2(Zr1-xTix)2O7, La2(Zr1-xTix)2O7 and (Y1-xLax)2Ti2O7 were synthesized and characterised by X-ray and neutron powder diffraction, electron microscopy and electron probe micro-analysis. Rare earth elements acted as non-radioactive analogues for actinide behaviour. The extent of solid solubility and factors governing exsolution were explored. The conductivity of Nd2(Zr1-xTix)2O7 ceramics was measured using impedance spectroscopy. Pyrochlores find application in a wide variety of technologies, including those which exploit the electrical properties of the pyrochlore structure. The effect of Ti substitution in Nd2Zr2O7 was studied and compared to the conductivity of monoclinic Nd2Ti2O7. The correlation between ionic mobility and critical radiation dose is discussed. Leaching from (Gd1.4Ce0.2La0.1Sm0.1Eu0.1)(Zr0.9Ti0.9Sc0.1In0.1)O7 was investigated. This composition facilitated comparison of numerous elemental dissolution rates from a single sample. Experimental conditions mimicked those likely in a repository at 1000m depth. Alteration of the solid was characterised by light and electron microscopy. The dissolved concentrations of leached elements were determined by inductively coupled plasma-mass spectrometry. Various synthetic routes were considered, to maximise the sample density.
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Davidson, Katrina Ann. "Protein refolding via immobilisation on crystal surfaces." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/345/.
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Is it possible to find an easy, generic method for protein refolding? The preparation of functionally active protein molecules from the unfolded state can be a difficult task. Although there are many well-established techniques for protein refolding, such as dilution, dialysis, chromatography and others, in many instances these methods can be time consuming and inefficient. A rapid, inexpensive and simple method for protein folding is a much sought after technique. Proteins in the unfolded state (either inclusion bodies or unfolded by chemical or physical means) are generally solubilised in solutions containing urea or guanidine hydrochloride. The removal of these molecules from the protein environment is commonly utilised as a method for triggering refolding. A new method for the refolding of biomolecular species has been developed via the formation of Protein Coated Micro-crystals (PCMC). The formation of PCMC is a recently developed method for the immobilisation protein upon the surface of a watersoluble excipient (salt, amino acid or sugar) via a co-precipitation reaction in a water miscible organic solvent. These proteins can then be used as immobilised biocatalysts in both the aqueous and organic phase. In the immobilisation of unfolded, solubilised protein, the solubilising agents (e.g. urea or guanidine hydrochloride) are removed from the protein environment as they are soluble in the organic phase. The removal of these molecules initiates protein folding during the coprecipitation process. In the course of this project, a number of proteins were studied in order to observe their behaviour in this immobilisation and simultaneous folding process. Lysozyme was utilised as it is an enzyme which is relatively simple to refold from the chemically unfolded state by conventional methods such as dilution. Upon immobilisation of lysozyme from the chemically unfolded state, up to 92% of the activity of the native protein was regained. The enzyme lipase, which is notoriously difficult to fold, was also used to determine the efficiency of this method under more challenging conditions. Lipase immobilised from the chemically unfolded state was seen to regain up to 36 % of the activity of the native protein.
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Johnson, Christopher D. "Immobilisation of arsenic in synthetic mineral phases." Thesis, University of Aberdeen, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252121.
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This thesis presents work relating to the synthesis, structure and stability of various arsenate phases having potential to immobilise high concentration arsenic wastes. Such wastes arise from mining and hydrometallurgy operations and the high arsenic concentrations, arising in tailings dams for example, represent an environmental concern. Large quantities of highly contaminated waste sludge are also generated by the co-precipitations of arsenic on ferric hydroxide floccs from low arsenic concentration waste streams. The disposal of this waste is becoming a prominent issue when cleaning minesite run off and drinking water. It is important therefore to consider the environmental impact of discarded arsenic residues and this project addresses the potential for its immobilisation in low stability minerals capable of return to mine sites. Two groups of phases with the potential for immobilisation of arsenic and other toxic metals are studied in this thesis. The first group are zinc arsenate zeolite analogues. These open framework structures also present the possibility of immobilization of other waste materials by ion exchange. The second group are a series of cadmium arsenate phases, which offer the potential for cadmium and arsenic immobilisation. This thesis examines the crystal structure, and synthesis of both groups of phases and examines their solubility and stability thus assessing their potential as waste immobilisation tools. The results of these studies has shown that although it is possible to make phases which are entirely composed of waste metals these phases are not stable enough for direct use in waste immobilisation processes. The crystal structures of several previously unpublished phases have been determined and a solubility product has been calculated for one of the phases.
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Scruton, S. L. "Ionic immobilisation of an anionic carbonylation catalyst." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380592.
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Albers, Willem M. "Immobilisation of biomolecules onto organised molecular assemblies." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268133.
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Flynn, Gabriella. "Immobilisation of DNA using the fluorous effect." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30866/.
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Reversible biomolecule attachment onto solid supports is of importance to many distinct research fields ranging from microarray development to the synthesis of metamaterials. One method used to immobilised biomolecules in a reversible fashion relies on non-covalent fluorous-fluorous interactions. The primary focus of this thesis was to investigate the immobilisation characteristics of DNA, tagged with a range of perfluorinated carbon chains, onto fluorinated solid supports. This work showed that the fluorous effect could be used to immobilise single stranded DNA onto patterned arrays permitting hybridisation to its complementary sequence. This duplex could then be removed via the fluorous tag, completely regenerating the surface and allowing for the immobilisation procedure to be repeated. This was then built upon by varying the fluorine content of the fluorinated carbon chain, allowing for comparison to be made between the fluorine content of the tag and the stringency of the washes required to remove the duplex from the surface. It was further noted that the effect of the linker group had a significant impact on the immobilisation densities of the DNA strands, with longer linkers showing higher hybridisation densities. Finally, DNA strands modified with fluorinated carbon chains were incorporated into DNA nanostructures. It was found that the inclusion of fluorous tags had a profound effect on the facial immobilisation orientation of the DNA nanostructures onto mica. It was found that the inclusion of one per fluorinated tag influenced the face on which the nanostructures were immobilised, with around 80 % of the structures immobilising on the face opposite to that modified with a fluorous tag. Therefore, it is thought that this work has potential application in reusable microarray development and as a means to control the deposition of nanostructures onto solids supports to aid in bottom-up self-assembly.
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Gokhale, Charlene. "The immobilisation of organic waste by geopolymerisation." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52533.
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Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: In excess of24 x 106 tons (1997, Eskom) of coal-derived fly ash is produced annually in South Africa for the production of electric power. A large quantity of this ash is disposed of as a solid waste in landfills, thus posing a serious environmental problem. Due to the shortage of landfill sites, new ways of utilising fly ash are needed. Recently several authors have shown that various combustion fly ashes can be converted into zeolites to obtain industrial products with applicability In environmental management. Geopolymerisation has emerged during the last few years as a possible solution to some waste stabilisation and solidification problems. Phenolic compounds have been shown to be toxic to soil microorganisms at the partsper- million level. Indeed several of the organic compounds classified by the U.S. Environmental Protection Agency as priority pollutants, are phenols. Immobilisation of phenols by adsorption on zeolites and encapsulation in a geopolymer appears to be a promising solution to this problem. This thesis reports a technique for the production of a low-silica sodium zeolitic material from fly ash (zeolite NaP1), and its application for the stabilisation of phenols by adsorption and subsequent encapsulation in a geopolymer matrix. A commercial zeolite, clinoptilolite was also utilised as an adsorbent. Due to their uniform pore sizes and large surface areas, zeoli tic materials are suitable for ion exchange and adsorption of certain organic substances. Adsorption data show that the commercial zeolite, clinoptilolite was an effective adsorbent for organics. Adsorption data showed that between 51.2ppm and 74.3ppm of chlorophenol or between 15.4ppm and 32.5ppm of phenol could be adsorbed. Physical encapsulation of the coated zeolite loaded with organic within a geopolyrneric matrix increased the compressive strength of the matrix from 28.80 kN to 40.79 kN. Leaching data for the various geopolymer matrices with encapsulated and loaded zeolites show no organics being leached from the system at a detection level of 2ppm. According to the SABS these would have been acceptable organic concentrations within a waste water stream. In utilising waste materials (fly ash and organic waste) and their reactive properties, it is now possible to create various geopolyrners that are not only strong enough to be used as constructionlbuilding materials, but are also effective immobilisation systems for organic waste containment.
AFRIKAANSE OPSOMMING: Meer as 24 x 106 tons (1997, Eskom) vlieg-as word jaarliks deur die verbranding van steenkool vir die produksie van elektrisiteit geproduseer. Die as, wat tans in groot hoeveelhede as soliede afval in vaste-afval stortingsterreine gestort word, word gesien as 'n groeiende omgewingsprobleem. 'n Tekort aan geskikte stortingsterreine maak die ontwikkeling van nuwe gebruike vir die vlieg-as dringend nodsaaklik. Geopolimerisasie van vlieg-as materiale, 'n proses wat die laaste paar jaar ontwikkel is, blyk 'n potensiele oplossing te wees vir sommige afval stabilisering en solidifikasie toepassings. Daar is bewyse dat fenoliese verbindings, selfs op 'n dele per miljoene (dpm) vlak, toksies is vir grondorganismes. Verskeie van die komponente wat deur die Amerikaanse Omgewingsbeskermingsagentskap (US EPA) as prioritats kontaminants geklassifiseer is, is ondermeer fenole. Die huidige werk ondersoek die adsorbsie van fenol op zeoliet NaPI en clinoptiloliet, gevolg deur fisiese omsluiting deur geopolimerisasie. Verskeie outeurs het onlangs verwys na die omsetting van verskeie verbrandings vlieg-asse na zeoliete om bruikbare industriele produkte (vir gebruik in die omgewingsveld) te vorm. Die tesis rapporteer 'n metode vir die produksie van 'n iae silika natrium zeolitiese material (zeoliet NaP!) uit vlieg-as en die gebruik daarvan in die stabilisering van fenole. 'n Kommersieel beskikbare zeoliet, clinoptiioliet, is ook gebruik as adsorbent. Uniforme porie groottes en hoe oppervlak areas maak zeolitiese materiale geskik vir ioonuitruiling, asook die adsorbsie van verskeie orgamese verbindings. Deur die fisiese omsluiting van die zeolitiese materiaal binne 'n geopolimeer matriks, kan materiale met beduidend hoe druksterktes, geproduseer word. Adsorbsie data het getoon data die kornmersiele zeoliet, klinoptilotiet, 'n effektiewe adsorbent vir organiese stowwe is. Adsorbsie waardes het gewissel tussen 51.2dpm tot 74.3dpm vir chlorofenol en 15.4dpm tot 32.5dpm vir fenol. Fisiese enkalsulering van die bebandelde zeoliet (coated fzeo) binne 'n geopolimeer matriks het die saamdrukbaarheidsterkte van die betrokke matriks verhoog van 28.80 kN to 40.79 kN. Logingsdata verkry vir die onderskeie geopolimeer matrikse het getoon dat geen van die organiese stowwe uit die matrikse vrygestel word nie. Indien die organiese stowwe wel vrygestel sou word, sou die waterfase konsentrasie onder 2 dpm, binne die aanvaarbare spesifikasie vir uitvloeisels volgens die SABS standard, gewees het. Verskeie geopolimere, wat nie slegs sterk genoeg is om as konstruksie materiale te dien nie, maar addisioneel effektief as immobilisasie medium dien, kan dus uit die reaktiewe eienskappe van afval materiale (vlieg-as en organiese afval) vervaardig word.
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Goldys, Anna M. "Immobilisation and application of bifunctional iminophosphorane organocatalysts." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:f4f28a47-0373-4b66-8537-d4e7028d4d63.
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Bifunctional iminophosphoranes, containing a triaryl-substituted iminophosphorane and bis(3,5- trifluoromethyl)phenyl thiourea on a single enantiomer scaffold are novel asymmetric superbase organocatalysts reported by the Dixon group in 2014. This thesis describes our efforts to expand their scope and utility in a variety of challenging chemical transformations. Chapter 2 describes the development and application of immobilised bifunctional iminophosphorane organocatalysts. We have successfully immobilised bifunctional iminophosphoranes on a crosslinked polystyrene support and applied this sold-supported catalyst to three challenging asymmetric reactions; namely the nitro-Mannich reaction of phosphinoyl ketimines and the conjugate addition of alkylmalonates and N,N-dimethyl β-keto amides to nitrostyrene. Very good yields, enantio- and diasteroselectivities were obtained in all cases. We have also demonstrated their use in a range of conjugate additions of cyclic 1,3-dicarbonyl compounds to nitroalkenes, which suffered from very slow reaction rates under tertiary amine-based bifunctional catalysis. In all cases, the immobilised bifunctional iminophosphoranes performed very well in comparison to their homogeneous counterparts. We have also demonstrated catalyst recycling over 10 cycles and application in a continuous flow system with a productivity of 7.20 mmol producth-1gcatalyst-1. to the ring-opening polymerisation (ROP) of cyclic esters. We have demonstrated the performance of bifunctional iminophosphorane organocatalysts in the ROP of L-lactide (LA), δ-valerolactone (VL) and ε-caprolactone (CL). The polymerisation of LA and VL proceeded rapidly and was well controlled, while only short lengths (> 100 DP) of poly(CL) could be prepared in a controlled fashion due to hypothesised competing initiation from the catalyst. We have shown that the polymerisation of LA using our catalyst may be considered a living polymerisation. Di-block co-polymers could also be successfully prepared via sequential monomer addition or through the use of macroinitiators. We then investigated the roles of the iminophosphorane and the thiourea component of the catalyst.
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Vial, Stéphanie. "Immobilisation d'enzymes dans des hydroxydes doubles lamellaires." Phd thesis, Clermont-Ferrand 2, 2005. https://tel.archives-ouvertes.fr/tel-00685757/document.
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Les biocapteurs constituent un défi pour le diagnostic médical, la surveillance des eaux naturelles. . . Dans ce travail, nous avons défini les conditions de précipitation de la structure Hôte par hydrolyse thermique de l'urée. Une nouvelle voie de synthèse d'HDL a été mise au point, utilisant la décomposition catalytique de l'urée par l'uréase. Une étude comparative des procédés d'immobilisation a permis de maîtriser la formation du matériau hybride et de contrôler la quantité d'uréase immobilisée, dont l'activité catalytique a été étudiée. L'élaboration des biocapteurs sous forme de multicouches nanostructurées HDL-Uréase a été réalisée par la technique Langmuir-Blodgett, et leur réponse a été évaluée. Cette première étude sur le confinement de protéines sur des matrices HDL, depuis l'élaboration de la matrice hôte jusqu'à la réalisation du biocapteur fonctionnel, ouvre des perspectives sur l'immobilisation d'autres enzymes et l'optimisation de films hybrides à propriétés biologiques
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Albers, Willem M. "Immobilisation of biomolecules onto organised molecular assemblies /." Espoo [Finland] : Technical Research Centre of Finland, 1999. http://www.vtt.fi/inf/pdf/publications/1999/P391.pdf.
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Morgan, F. J. "Growth and immobilisation of a Streptomyces sp." Thesis, University of Manchester, 1986. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506608.
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DECHAMP, CHRISTINE. "Immobilisation de cellules dans les matrices polymeriques." Strasbourg 1, 1987. http://www.theses.fr/1987STR10730.
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Valat, Christophe. "Immobilisation de biomolécules sur des surfaces conductrices." Aix-Marseille 2, 1999. http://www.theses.fr/1999AIX22054.
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Ce travail a eu comme objectif la mise au point d'une methode d'immobilisation covalente de biomolecules sur des electrodes imprimees, et leur utilisation dans deux applications de dosages utilisant une detection electrochimique. Ces electrodes sont obtenues par impression d'une encre conductrice a base de polystyrene et de graphite. Elles sont fonctionnalisees par oxydation, puis liees de facon covalente avec la molecule, ligand d'anticorps ou oligonucleotides en utilisant un reactif bi-fonctionnel. L'utilisation d'une surface conductrice permet la realisation d'un dosage electrochimique base sur le couplage de la detection de molecules redox avec l'activite d'enzymes. Les deux types de biomolecules immobilisees sont a la base des deux applications developpees dans ce travail, respectivement un immunocapteur et un capteur a adn dans la premiere application, l'immobilisation de proteine a a permis la capture d'anticorps sur les electrodes, et la realisation d'un dosage automatise de ces anticorps ainsi que la regeneration de la surface de capture. Les resultats obtenus ont demontres la stabilite de la proteine a immobilisee vis a vis du traitement de regeneration, ainsi que l'utilite de l'utilisation de la convection forcee pour accelerer les etapes de capture des anticorps sur la proteine a. Par ailleurs l'etude de l'affinite du capteur a proteine a vis a vis de differents isotypes d'anticorps, a permis la mise au point du dosage d'anticorps polyclonaux et monoclonaux, avec une limite de sensibilite de l'ordre d'une nm. Dans la deuxieme application etudiee, l'immobilisation de sondes oligonucleotidiques sur les electrodes imprimees a permis d'effectuer un dosage de molecules d'adn cibles, dans un test en microplaques utilisant alternativement une detection colorimetrique ou electrochimique. Cette etude a porte sur le choix d'une methode d'immobilisation, l'optimisation des parametres cinetiques de fixation covalente des oligonucleotides, et des conditions d'hybridation. Le dosage d'une molecule d'adn de 441 paires de bases marquee a la biotine a ete effectue et montre une limite de sensibilite de l'ordre de 10 pm dans le cas de l'utilisation de la detection colorimetrique et electrochimique.
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Ghous, T. "Flow injection determination of drugs by enzyme inhibition." Thesis, University of Hull, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296138.
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Selle, Markus. "Immobilisierung von Übergangsmetall-haltigen Komplexen des Phthalocyanin und des Salen-Typs in mesoporösen Molekularsieben des Typs MCM-41." [S.l. : s.n.], 2000. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8549104.
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Smith, Graham Michael. "Enzyme immobilisation and catalysis in ordered mesoporous silica /." St Andrews, 2008. http://hdl.handle.net/10023/573.
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Soukrati, Amina. "Photochimie, photophysique et immobilisation d'enzymes dans des hydrogels." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211641.
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Smith, Graham Murray. "Enzyme immobilisation and catalysis in ordered mesoporous silica." Thesis, University of St Andrews, 2008. http://hdl.handle.net/10023/573.
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A range of mesoporous materials based on SBA-15 have been prepared and characterised. The materials were templated by neutral block copolymer P123, and typically have a hexagonal (p6mm) pore structure, with high surface areas and narrow pore size distributions. The removal of the surfactant template by calcination and solvent extraction has been investigated. The aqueous stability of this material, and the hydrolysis of the surface was studied. Organic functional groups were incorporated into the silica surface by co-condensation, or by post synthesis grafting. A range of functional groups were incorporated, including amine, carboxy, allyl and thiol groups. The pore size of the materials was controlled by the addition of trimethoxybenzene during synthesis, which significantly increased the pore size and uptake capacity of the materials. The adsorption of CALB by SBA-15 was investigated, with support materials extracted by calcination or solvent extraction. Rapid uptake at high loading was observed, with a maximum loading of 450 mg g-1 measured. The leaching of the enzyme from the support was investigated, and found to be high with unfunctionalised supports. The leaching from functionalised supports incorporating sulfur groups was significantly reduced. The activity of the immobilised CALB was measured by tributyrin hydrolysis in aqueous media, and by enantioselective transesterification of (R)-1-phenylethanol in organic media. The effect of surface functionalisation for reusability and thermal stability in aqueous systems was investigated. Preliminary studies of supported CALB for dynamic kinetic resolution were carried out, with an investigation of acidic zeolites and a mesoporous supported catalyst for 1-phenylethanol racemisation. The encapsulation of immobilised CALB was investigated, and the activity and reusability of these systems studied.
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Quesada, Macarena Peran. "Cellular distribution and immobilisation of GABA(_A) receptors." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4611/.
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Synaptic inhibition in the vertebrate central nervous system is largely mediated by type A GABA receptors (GABA(_A)R). The clustering of (GABA(_A)R) at discrete and functionally significant domains on the nerve cell surface is an important determinant in the integration of synaptic inputs. To discern the role that specific GABA(_A)R subunits play in determining the receptor's cell surface topography and mobility, recombinant GABA(_A)Rs, comprising different GABA(_A)R subunit combinations, were transiently expressed in COS7, HEK293 and PC12 cells. In addition, a series of domain swapping experiments were performed in order to elucidate which regions of the protein are important in mobility/anchoring of receptors. The cellular localization and lateral mobility of the recombinantly expressed GABA(_A)Rs were determined by immunocytochemistry and Fluorescence Photobleach Recovery (FPR), respectively. The results presented in this thesis show that GABA(_A)R al subunits are recruited by the β3 subunits from an internally sequestered pool and assembled into a population of GABA(_A)Rs that are spatially segregated into clusters and also immobilised on the cell surface. FPR experiments on recombinant GABA(_A)R containing al-a6 subunits expressed in COS? cells showed restricted mobilities consistent with mobility constants determined for native GABA(_A)Rs expressed on cerebellar granule cells. Furthermore, the intracellular loop domain M3/M4 of the a1 subunits was found to be required for anchoring recombinantly expressed GABA(_A)Rs in C0S7 and cerebellar granule cells in culture, but not for GABA(_A)R clustering at the cell surface.
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Roach, Peter C. J. "A new immobilisation process for whole cell biocatalysis." Thesis, University of Huddersfield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247380.
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Lynch, Michele M. "Enzyme immobilisation on mesoporous silica, inspired by chaperonins." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10056498/.
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In nature, chaperonins stabilise enzymes and protect them from high temperature and unfavourable solution conditions. We are inspired by some of chaperonins’ fundamental properties when investigating materials for enzyme immobilisation. In this project, mesoporous silica SBA-15 is used as a synthetic chaperonin analogue because of its controlled mesopore diameter and its negatively charged surface. Mesoporous silica SBA-15 have been synthesised by an acidic sol-gel method. The morphologies and textural parameters of the SBA-15 have been characterised using electron microscopy, gas physisorption, and small-angle Xray scattering. The synthesised SBA-15 samples are used to immobilise several model proteins: myoglobin, lysozyme, trypsin, and pepsin. At equilibrium, protein immobilisation can be described by the Langmuir model of physical adsorption. The maximum amount of protein that can be adsorbed onto SBA-15 increases with increasing pore diameter. The kinetics of adsorption of the protein myoglobin is found to be affected by the pore size of the SBA-15, with the protein diffusing faster through a larger pore. Immobilising enzymes to SBA-15 is shown to increase their biocatalytic activity under some solution conditions. For myoglobin and lysozyme, the protective effects were strongest in solutions where the enzyme is strongly electrostatically attracted to the silica surface. Immobilised myoglobin is also found to be protected from digestion by the protease pepsin. For trypsin, the relationship between electrostatic attraction and improved activity was inconclusive. SBA-15 pore size was shown to affect the activity of the smallest enzyme, lysozyme. In summary, this thesis recommends the following prioritisations for enzyme immobilisation: strong electrostatic attraction between enzyme and material, followed by pore size just exceeding the diameter of the enzyme. By determining the relative importance of these parameters, this thesis increases the fundamental understanding of enzyme immobilisation by physical adsorption onto porous materials.
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Milutinovic, Miléna. "Immobilisation d'hydrogel redox pour la détection par électrochimiluminescence." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14411/document.
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Ce travail de thèse a pour objectif l’étude de l’électrochimiluminescence (ECL) et son application pour le développement de nouvelles techniques analytiques. De par son importante sensibilité, l’ECL est une technique performante pour des applications telles que les diagnostics cliniques ou la chimie environnementale (présence d’agents contaminants dans l’eau ou la nourriture). L’immobilisation du luminophore ECL est réalisée généralement sur une phase solide. Cette étape constitue une phase essentielle pour obtenir une méthode d’immobilisation rapide, simple, flexible et efficace de ces luminophores ECL, tout en permettant une utilisation pour des systèmes variés. La première partie de ce travail présente l’optimisation de la déposition électrochimique de films de métallopolymère de ruthénium et son application pour la détection enzymatique. Un film d'épaisseur micrométrique de cet hydrogel redox a été préparé par voltamétrie cyclique. Cet hydrogel immobilisé a permis la détection d’un substrat modèle (le glucose) en utilisant l'enzyme glucose déshydrogénase. La seconde partie se concentre sur le développement d’une nouvelle méthode de photodéposition d’un polymère. Celle-ci permet l’immobilisation de centres actifs sur des régions sélectives. En utilisant les techniques de photolithographie, les figures du masque sont projetées sur la surface des électrodes. Cela permet la réalisation de spots micrométriques dont la taille, forme et épaisseur sont modulables. Les propriétés électrochimiques des films nanométriques obtenus sont comparables à ceux obtenues par électrodéposition. De même, les spectres ECL réalisés avec polymères immobilisés par ces deux stratégies sont identiques. Ces résultats montrent que les états excités induits lors de l’ECL sont identiques avec les deux techniques d’immobilisation. Le développement d'un tel procédé constitue une alternative prometteus pour la réalisation de réseaux de spots ECL différenciés et permettant la détection multipléxée par imagerie ECL. Dans la troisième partie de ce travail, nous avons associé la spectroélectrochimie et l'imagerie ECL pour contribuer à l’étude des mécanismes ECL au niveau d'une bille micrométrique fonctionnalisée par des complexes de ruthénium. En combinant microscopie de fluorescence et imagerie ECL, la distribution des sites électroactifs et des sites ECL a pu être mise en évidence. A partir de cette étude, nous pouvons clarifier les mécanismes conduisant à l'émission ECL au niveau de ces billes fonctionnaliséesThe main goal of this thesis was to study electrogenerated chemiluminescence (ECL) and its application in development of new analytical techniques. Due to its high sensitivity, ECL presents a powerful method for applications in clinical diagnostic and environmental chemistry (presence of contaminants in water or food). The immobilisation of an ECL luminophore is usually performed on a solid phase. This step is an essential point to obtain a technique for fast, simple, flexible and effective immobilisation of ECL luminophores with possibility of applications in various configurations. The first part of this work presents the optimisation of the electrochemical deposition of a ruthenium metallopolymer and its application in enzymatic detection. A redox hydrogel film with micrometric thickness was prepared using cyclic voltammetry. This immobilised hydrogel allows the detection of model substrate (glucose) using enzyme glucose dehydrogenase. The second part of this thesis is focused on the development of a new photodeposition method for the ECL polymer immobilisation. This method allows region-selective immobilisation of active centres. Using photolithographic methods, the figures from the mask are projected on the electrode surface. This allows the formation of micrometric spots which size, shape and thickness is modulated. Electrochemical properties of obtained nanometric films are comparable with those of electrodeposited films. Also, ECL spectra recorded with both immobilisation strategies are identical. It shows that the ECL excited state is the same. The obtained photopatterns were imaged using ECL. The development of such process presents an alternative for realisation of different ECL spot arrays and allows multiplexed detection by ECL imaging. In the third part of this work we have associated spectroelectrochemistry and ECL imaging to study the ECL mechanisms at the level of a single microbead, functionalised with ruthenium complex. Combining fluorescence microscopy and ECL imaging, the distribution of electroactive and ECL sites have been highlighted. From this study we can clarify the mechanism that leads to ECL emission at the level of functionalised beads
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Szili, Endre Jozsef, and endre szili@unisa edu au. "Covalent immobilisation of proteins for biomaterial and biosensing applications." Flinders University. School of Chemistry, Physics and Earth Sciences, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20080724.214815.
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This thesis focuses on surface science and bioengineering investigations, first for the development of an improved biomaterial for orthopaedic implant applications, and second, for the development of a biosensor device for biomedical diagnostics. A key component considered in this thesis was the covalent linkage of proteins to the materials surface for retaining the proteins immunological and biological activities and for generating a functional interface.
Part 1 of this thesis investigated surface modification procedures for improving the bioactivity of titanium substrates. Titanium is first coated with a bioactive silica film grown by plasma enhanced chemical vapour deposition (PECVD), referred to as PECVD-Si-Ti. In previous studies, the bone-implant integration process was enhanced 1.6-fold for titanium implants coated with PECVD-Si films compared to uncoated titanium implants in vivo. However, in vitro studies carried out in this thesis showed that the growth of MG63 osteoblast-like cells was 7-fold higher on uncoated titanium compared to PECVD-Si coated titanium. Therefore, to improve cell growth on the surface and, by inference, the integration of PECVD-Si-Ti implants into bone tissue, the implants surface was functionalised with a mitogenic factor, insulin-like growth factor-1 (IGF-1). This was accomplished by modifying the PECVD-Si-Ti surface with an alkoxysilane, 3-isocyanatopropyl triethoxysilane (IPTES), and then by covalent bioconjugation of IGF-1 through isocyanate-amino chemistry. After 72 h of in vitro cell culture in serum-free medium, the growth of MG63 cells was enhanced 1.9-fold on IPTES functionalised PECVD-Si-Ti, which was loaded with covalently immobilised IGF-1 compared to IPTES functionalised PECVD-Si-Ti without IGF-1 (isocyanate reactive groups were quenched with ethanolamine hydrochloride). The attachment and adhesion of MG63 cells were also enhanced on PECVD-Si-Ti by the covalently immobilised IGF-1 in serum-free cell culture conditions. Therefore, the bioactivity of PECVD-Si-Ti was improved by covalently linking IGF-1 to the substrate surface through isocyanate-amino chemistry.
Part 2 of this thesis involved the development of a new optical interferometric biosensor. The biosensor platform was constructed from electrochemically-prepared thin films of porous silicon that acted as a sensing matrix and transducer element. By reflective interferometry using white light, an enzyme-catalysed reaction was discovered (horseradish peroxidase (HRP) mediated oxidation of 3,3,5,5-tetramethylbenzidine (TMB)), which led to an acceleration in the rate of porous silicon corrosion and represented the biosensors readout signal. We discovered that another substrate, which is also oxidised by HRP, OPD, produces an even more pronounced readout signal. The HRP-OPD system was used in an immunoassay for detecting human IgG from an Intragam solution. An important part in the design of the biosensor was the surface functionalisation approach where anti-human IgG, referred to as the capture antibody, is immobilised on the porous silicon surface. The readout signal (produced from the capture of human IgG) was enhanced 4-fold on the porous silicon biosensing platform functionalised with covalently linked anti-human IgG through isocyanate-amino chemistry compared to the porous silicon biosensing platform functionalised with adsorbed anti-human IgG. The optimised biosensor was used to detect IgG from a total human protein concentration of Intragam to a sensitivity of 100 ng/ml.
In summary, isocyanate-amino bioconjugate chemistry was used to covalently link either IGF-1 to PECVD-Si-Ti for improving the biological activity of the orthopaedic implant and to covalently link IgG to porous silicon for developing a sensitive biosensor for the detection of proteins. This surface chemistry approach is very useful for biomaterial and biosensing applications.
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Lin, Shiming. "Carboxyl-terminal cysteinylation of immunoglobulin G for orientated immobilisation." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388509.
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Cho, Byoung-Mi. "Purification and immobilisation of mushroom polyphenol oxidase (E.C. 1.14.18.1.)." Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254958.
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Sousa, Ana M. L. "Bioinspired materials for enzyme immobilisation and transport of biomolecules." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28673.
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Protein and enzyme immobilisation on synthetic material surfaces enables a range of applications from biosensing to industrial biocatalysis. There are several immobilisation techniques, but common methods need multiple preparation steps or are material-dependent, which reduce the effectiveness and success of biosensing/industrial applications. In this thesis, the possibility of using plant-based polyphenol coatings to immobilise a range of proteins and enzymes (avidin, immunoglobulin G, acid phosphatase, chymotrypsin, lactate dehydrogenase, horseradish peroxidase) on polymeric or oxide materials (cellulose, polyester, silica, alumina and stainless steel) was shown for the first time. Polyphenols are in abundance in nature and less costly than dopamine (common immobilisation agent). Polyphenols were more effective than physisorption and polydopamine coatings for certain combinations of materials and proteins. Several parameters that can influence the immobilisation procedure were evaluated showing that there is a dependence on the coating and immobilisation pH as well as the type of coating and material. Polyphenol coatings were also used to functionalise nanoporous anodic aluminium oxide (AAO) membranes in order to measure molecular transport through nanopores. Inspired by the biological nanopores that enable the highly specific and efficient separation of a range of biomolecules, we used AAO membranes with a pore size matching the biological nuclear pore complex for controlling the diffusion of molecules through the pores. AAO membranes also match the requirements for optical waveguide spectroscopy (OWS) that was used to characterise and differentiate processes that occurred inside and above the nanoporous membranes. In a second approach, a nanoporous membrane was placed between two gaskets to be suspended on the flow cell. This work brings a new concept of how the molecular diffusion can be characterised, which is important for controlling the transport of biomolecules. It was possible to monitor in situ biocatalytic reactions as well as nanopore transport control by using a responsive polymer that was able to allow and restrict the transport of molecules.
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Bostock, Emma Louise. "Building physiological reserve in immobilisation : does nutritional supplementation work?" Thesis, Manchester Metropolitan University, 2015. http://e-space.mmu.ac.uk/688/.
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Introduction: Disuse models, such as limb immobilisation, result in profound changes in skeletal muscle morphology and function. Exercise prescription would be the recommended intervention to prevent immobilisation-induced atrophy and declines in maximal voluntary strength. Nutritional supplementation may stand as a viable intervention to combat muscle atrophy with disuse, when exercise is an unpractical therapeutic option. Aims: To (1) investigate the multifactorial effects of short-term upper limb sling immobilisation and (2) determine whether three potential protein-sparing modulators (essential amino acids (EAA), omega-3 (w-3) and vitamin D) would attenuate the anticipated deleterious effects of immobilisation. Methods: Measures of muscle and sub-cutaneous adipose thickness (Brightness mode ultrasonography), body composition (dual-energy x-ray absorptiometry), arm girth (anthropometry), isometric and isokinetic elbow torque (dynamometry), co-contraction (electromyography (EMG)), muscle fatigability (dynamometry and EMG), arterial blood flow (Doppler ultrasound) and endocrine profile (enzyme-linked immunosorbent assay and colorimetry), were taken before and after arm immobilisation in a mixed sex population. Supplementation of EAA (n = 9 vs. placebo n = 7) during three weeks of immobilisation, w-3 (n = 8) or vitamin D (n = 8) during two weeks of immobilisation (placebo n = 8) and EAA for two weeks pre-immobilisation (n = 5 vs. placebo n = 5). Main findings: Immobilisation resulted in decreases in muscle thickness, arm girth, lean mass, isometric and isokinetic elbow torque, and an increase in sub-cutaneous adipose thickness. Muscle fatigability, resting arterial blood flow, EMG co-contraction and endocrine profile were unchanged. At the current dosage w-3 supplementation only attenuated the increase in sub-cutaneous adipose thickness. Despite some trends, neither w-3 nor vitamin D supplementation attenuated any other parameters. EAA supplementation during immobilisation impacted positively on the immobilisation-induced changes in the structural and functional characteristic of the remaining muscle. EAA supplementation before immobilisation did not attenuate the immobilisation-induced changes in muscle structure and function. Conclusion: Although EAA supplementation only showed some benefit to muscle size and function with immobilisation, it was confirmed that the sling immobilisation model used in the thesis, is a suitable model for observing the effects of relatively short-term immobilisation. The findings of the thesis are relevant to both sporting (e.g. off-season detraining modulation) as well as clinical (e.g. injury/illness induced short-term immobilisation/bed rest) populations. This relatively short-term sling immobilisation provides a model to be used to assess other supplements and treatments in future studies. The modest effect of supplementation suggests further research into either: a) more at risk populations (e.g. injury or ageing); b) larger doses of these supplements.
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Sadler, Andrew Michael. "The separation and immobilisation of a yeast intracellular enzyme." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/847980/.
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The aim of this work was to investigate the problems involved in production and separation of a yeast microsomal enzyme, cytochrome P450. Immobilisation of the microsomal preparation, and utilisation of the immobilised system for the removal of polycyclic aromatic hydrocarbons, particularly the carcinogen benzo(a)pyrene [B(a)P], from aqueous systems was also investigated. High recoveries of the microsomal enzyme were obtained using rapid, low-speed centrifugation (5 minutes, 3000xg) by prior precipitation with a non-ionic polymer, polyethylene glycol (PEG). PEG was found to effectively replace centrifugal acceleration. A semi-empirical mathematical model of the process based on the size distribution of the agglomerates formed and the proportion of the agglomerates sedimented by centrfugation was developed. The effect of PEG was consistent with its increasing the mean effective diameter of protein agglomerates in proportion to PEG concentration to an exponent of 0.619 and with its increasing the spread of the size distribution in proportion to the mean effective agglomerate diameter. Binding spectra studies established that B(a)P binds to the active site of yeast cytochrome P450 and is unaffected by PEG. The B(a)P assay by fluorescence following hexane extraction was also unaffected by PEG. The stability of the microsomal cytochrome P450 preparation at different temperatures was investigated. The enzyme half-life was 66 minutes at 37° and was also unaffected by PEG. The enzyme preparation was satisfactorily immoblilsed by encapsulation in calcium alginate gel and enzyme distribution profiles were determined in sections of alginate stained with coomasie blue by a novel technique using a scanning optical densitometer, Diffusivity coefficients of B(a)P and NADP in alginate gel beads were determined as 7.5 and 2.5 x 10[-10] m[2]/S, respectively by the Tanaka method, fitting solute depletion profiles to Crank's theoretical model. The microsomal enzyme preparation immobilised in alginate beads was used to remove B(a)P from aqueous solution. B(a)P removal was shown to be by a non-specific affinity absorption mechanism and the removal profile was found to correspond well to a theoretical model of a diffusion-reaction system, for an affinity ligand system. The activaiton energy for deactivation of microsomal P450 was measured as 33.56kJ/mole.
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Dignan, Rosemary Anne. "The selective immobilisation of chiral intermediates in asymmetric synthesis." Thesis, Swansea University, 2002. https://cronfa.swan.ac.uk/Record/cronfa42631.
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The advantage of solid phase synthesis is that the products can be isolated and purified simply by filtration. However, the reaction conditions required often lead to different kinetic behaviour, differences in reactivity and solvation and other problems, not encountered in solution phase reactions. This thesis describes an approach at utilising the ease of purification associated with solid-phase synthesis without encountering the problems associated with two-phase reaction systems. It was achieved by selectively immobilising a bipyridyl-tagged chiral auxiliary and a bipyridyl-tagged oxazaborolidine catalyst by interaction by with a resin-bound transition metal upon completion of the solution-phase reaction. Chapter one is a literature review detailing some of the different approaches that have been reported in exploiting the benefits of solid-phase purifications whilst avoiding the associated problems. Soluble polymeric supports, fluorous labelling and some more unusual methods are investigated. Chapter two is a general introduction to how chiral auxiliaries can stereochemically influence reactions. Chiral auxiliary mediated alkylations, aldol reactions, conjugate additions and Diels-Alder reactions are focussed on. Chapter three details the complete synthesis of (R,R)-4,4'-bis-[1-(4,5-diphenyl-3-propionyl-imidazolidinonyl)-N-methyl]-2,2'-bipyridine, a bipyridyl-tagged chiral auxiliary. An investigation into its ability to reversibly bind to a resin-bound transition metal is then reported. Chapter four describes the extensive study on the reactivity of the tagged chiral auxiliary, concentrating on chiral alkylations, halogenations and aldol reactions. Chapter five is an account of how the selective immobilisation approach was extended to include chiral oxazaborolidine catalysts. A general introduction to oxazaborolidine catalysts is provided. The total synthesis of the bipyridyl-tagged oxazaborolidine, (S,S)-4,4'-bis-[4-(2-amino-3-hydroxy-3,3-diphenyl-propyl)phenoxymethyl]-2,2'-bipyridine is reported and the investigation into its ability to reversibly bind to a resin- bound transition metal is described. The chiral reduction of acetophenone using the tagged catalyst and the subsequent recovery of the catalyst is then explored.
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Wynands, Lucie. "Synthèse d'organocatalyseurs à structure saccharidique et immobilisation sur silice." Amiens, 2014. http://www.theses.fr/2014AMIE0102.
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L'organocatalyse joue un rôle capital dans le développement de nouvelles méthodes permettant d'effectuer des synthèses stéréosélectives. Partant du constat que peu d'organocatalyseurs intègrent un squelette glucidique, la synthèse de nouveaux α-aminotétrazoles sous forme furanose et pyranose a été réalisée, et ces composés ont été étudiés dans la réaction d'aldolisation. Une étude de résolution enzymatique du produit d'aldolisation a également été entreprise, et elle a conduit à la mise au point de conditions pour une réaction « one pot—3 steps » organo et biocatalysée qui fait intervenir une cascade réactionnelle de réaction d'aldolisation, déshydratation et d'addition de Michaël. Afin de faciliter l'extraction du catalyseur en fin de réaction et son recyclage, l'immobilisation sur silice a été réalisée. Dans un premier temps, des sucres simples ont été utilisés pour faire les mises au point. L'affinité des matériaux obtenus a été examinée pour la concanavaline A. Puis de façon similaire, l'immobilisation du glycocatalyseur a été réalisée sur nanoparticules sphériques préparées par le procédé Stöber et sur une silice mésoporeuse, la SBA-15. Les matériaux obtenus ont également été étudiés comme organocatalyseurs dans la réaction d'aldolisationNew stereoselective synthesis methods are of peculiar interest. In this field organocatalysis plays an important part. We noticed that few organocatalysts bearing a saccharidic skeleton have been developed, the synthesis of new aaminotetrazole on a furanose or pyranose ring was undertaken, and those compounds were studied in the aldolisation reaction. An enzymatic resolution study of the aldol product was also done and lead to the settlement of conditions for an organo and bio-catalyzed one pot- 3 steps reaction, which involve a cascade of successive aldolisation-dehydration- Michael addition. In order to facilitate catalyst removal at the end of the reaction and its recycling, immobilization on silica was performed. First, simple carbohydrates were used to settle reaction conditions. The binding affinity of those materials toward concanavaline A was examined. Then in the same way, glycocatalysts were immobilized on spherical nanoparticles prepared via the Stôber process and on mesoporous silica (SBA-15). The obtained materials were also studied as organocatalysts in the aldol reaction
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De, Lange Stephanie Siobhan. "Tremors in white rhinoceros (Ceratotherium simum) during chemical immobilisation." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/53294.
Full textAbstract:
White rhinoceros (Ceratotherium simum) are susceptible to developing muscle tremors during chemical immobilisation induced by potent opioid receptor agonists. Whether these tremors result directly from the actions of the opioids or from other physiological changes associated with immobilisation is unknown. A pilot study on 8 boma-managed chemically immobilised rhinoceros was conducted using different supportive interventions for the animal?s cardiorespiratory systems to test whether these interventions had an effect on tremors during chemical immobilisation. The pilot study revealed that butorphanol, a partial opioid agonist/antagonist, combined with nasotracheal oxygen insufflation, compared to the control, was the only intervention that decreased the observed tremor intensity and adequately stabilized the rhinoceros cardiorespiratory system in the immobilised rhinoceros. With this knowledge and using the same drug protocol (etorphine and azaperone and hyaluronidase) and supportive interventions (butorphanol and nasotracheal oxygen insufflation), a field study was conducted to quantify tremors, both objectively and subjectively, and record various physiological responses of 14 rhinoceros during a 25 minute chemical immobilisation period. Butorphanol was injected intravenously 6 minutes after the rhinoceros became laterally recumbent. Tracheal oxygen insufflation was also administered from this time. Occurrence (intensity) of tremors was assessed every minute throughout the 25 minute immobilisation period, both subjectively by human observation, and objectively by accelerometer data loggers placed on the front leg. Arterial blood pH, oxygen and carbon dioxide levels, electrolytes and plasma catecholamine concentrations were measured at 5 minute time points. The tremor intensity was highest (5 minutes 28 counts/min) just after the animals became recumbent, but decreased (3 counts/min) after butorphanol and nasotracheal oxygen insufflation was administered. Tremor intensity was correlated with the mean pH, arterial partial pressure of oxygen, serum potassium and median plasma adrenaline concentration. High tremor intensity occurred when plasma adrenaline concentrations were elevated and when hypoxaemia and acidaemia were at their worst. Hypoxaemia and acidaemia, both physiological stressors, were correlated with the increased plasma adrenaline concentrations. These correlations indicate that changes in blood oxygenation and pH could be the driving force behind the changes in the tremor intensity. Butorphanol and nasotracheal oxygen insufflation corrected the hypoxia and acidaemia and reduced tremor intensity. Therefore, tremor intensity could possibly indicate the severity of the pathophysiological effects of the capture drugs on a rhinoceros cardiorespiratory system.Dissertation (MSc)--University of Pretoria, 2015.
tm2016
Paraclinical Sciences
MSc
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Zhang, Liping. "Immobilisation de catalyseurs moléculaires de polymérisation d’oléfines sur nanomatériaux." Thesis, Toulouse, INPT, 2014. http://www.theses.fr/2014INPT0013/document.
Full textAbstract:
Le présent travail de thèse décrit le développement de systèmes actifs de polymérisation d’oléfines basés sur des métaux de fin de transition (nickel et fer) supportés sur des nanomatériaux. Le chapitre I décrit l’état de l’art des systèmes catalytiques supportés ou non pour la polymérisation d’oléfines. Dans le chapitre II, nous décrivons la polymérisation de l’éthylène en utilisant des catalyseurs de nickel contenant un groupement –NH2 pour leur immobilisation covalente sur nanotubes de carbone ; montrant l’influence positive de l’immobilisation : les catalyseurs ainsi supportés sont en effet à la fois plus actifs et conduisant à des polymères de plus haut poids moléculaire. Dans le chapitre III, des complexes de fer contenant un groupement pyrène sont décrits et immobilisés sur nanotubes de carbone par interaction non covalente π-π. Dans ce cas, à la fois les systèmes homogènes et leurs analogues supportés catalysent la réaction de polymérisation de l’éthylène avec des activités particulièrement élevées. Il a également pu être mis en évidence l’importante influence du support carboné sur les performances du système catalytique ainsi que sur la structure des polymères obtenus. Différents types de complexes de nickel contenant un ligand imino-pyridine et différents groupes polyaromatiques ont été synthétisés et leur utilisation en polymérisation de l’éthylène est décrite dans le chapitre IV. L’influence de l’addition de faibles quantités de matériaux nanocarbonés (nanotubes de carbone ou graphène) au milieu réactionnel a ainsi été étudiée. Le graphène s’est dans ce cas révélé particulièrement bénéfique sur les performances du catalyseur. Enfin, le chapitre V décrit la polymérisation de l’isoprène à l’aide de catalyseurs de fer contenant des groupements polyaromatiques permettant leur immobilisation à la surface de nanoparticules de fer. Ces systèmes ont ensuite pu être confinés dans des nanotubes de carbone. Les systèmes catalytiques décrits sont particulièrement actifs produisant des polyisoprènes à température de transition vitreuse élevée et avec une haute sélectivité trans-1,4-polyisoprèneThis present thesis deals with the development of active olefin polymerization catalysts based on late transition metal (nickel and iron) imino-pyridine complexes supported on nanomaterial. Chapter I gives a comprehensive literature review of unsupported and supported ethylene polymerization catalyst. In Chapter II we report the ethylene polymerization studies using nickel complexes containing an –NH2 group for covalent immobilization on multi-walled carbon nanotubes (MWCNTs) of the corresponding precatalysts. Comparison of the homogeneous catalysts with their supported counterparts evidenced higher catalytic activity and higher molecular weights for the polymers produced. In Chapter III, iron complexes containing a pyrene group have been synthesized and immobilized on MWCNTs through non-covalent π-π interactions between pyrene group and surface of MWCNTs. Activated by MMAO, both the iron complexes and immobilized catalysts show high activities for ethylene polymerization. It was possible to evidence that MWCNTs have a great influence on the catalytic activity and on the structure of the resulting polyethylenes. Imino-pyridine nickel complexes containing various kinds of aromatic groups have been synthesized in Chapter IV and polymerization conditions in the presence and in the absence of nanocarbon materials, such as MWCNTs or few layer graphene (FLG), are discussed. For those nickel catalysts bearing 1-aryliminoethylpyridine ligands, the presence of MWCNTs in the catalytic mixture allows the formation of waxes of lower molecular weight and polydispersity, whereas the presence of FLG proved to be beneficial for the catalytic activity. In Chapter V, isoprene polymerization catalyzed by iron complexes containing polyaromatic groups and non-covalently supported on nanoparticles and confined into the inner cavity of MWCNTs (Cat@NPs and Cat@NPs@MWCNTs) are investigated. Iron complexes show excellent activity for the isoprene polymerization and produced high glass temperature polyisoprene with a high trans-1,4-polyisoprene selectivity. Polymer nanocomposites are produced by supported catalysts and, transmission electron microscopy (TEM) evidenced efficient coating of the resulting polyisoprene around the oxygen sensitive iron nanoparticles
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Shirley, Robin. "Alternative binder systems for the immobilisation of waste streams." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/8088/.
Full textAbstract:
This work aimed to assess the potential for valorisation of waste materials in order to minimise the environmental impact of hazardous air pollution control residues by solidification/stabilisation. The potential for immobilisation in a primarily pozzolanic matrix was examined. Pulverised fuel ash resulting from the co-combustion of coal and biomass, which did not meet end of waste criteria for construction purposes, and a waste caustic solution resulting from the cleaning of aluminium extrusion dyes were utilised as reagents. A range of variables were examined with regards to mix design and curing conditions. The mineralogy, reaction kinetics and pore structure of the samples were examined and performance assessed based on physical tests and leaching performance with regard given to current legislation within the UK. A detailed understanding of the treatments potential was thereby developed along with an understanding of the factors determining the observed performance. The treatment option proved unsuccessful primarily due to the lack of potential for immobilisation of the high levels of soluble chloride salts present in the air pollution control residues and the gas production typically observed when blending air pollution control residues with a caustic solution. Compared to more traditional cement based solidification/stabilisation systems other disadvantages were observed relating to slower reaction kinetics and therefore the need for increased curing temperatures, matrix durability, and increased sulphate leaching. Nevertheless the reagents showed some potential and may be suitable for use treating alternative waste streams, providing an economic option which is beneficial for the environment as a whole. In addition the impact of the known variability in air pollution control residue composition, on the potential treatment by solidification/stabilisation with cement was assessed. Significantly different performance was observed which implied the necessity to modify any such treatment.
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Pfitzer, Silke. "The respiratory physiology of opioid immobilisation in African antelope." Thesis, Pfitzer, Silke (2019) The respiratory physiology of opioid immobilisation in African antelope. PhD thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/54072/.
Full textAbstract:
This thesis addresses the mitigation of opioid-induced respiratory depression in wild African antelope species.
Potent opioids such as etorphine or thiafentanil are often used for the immobilisation of wild herbivores. One disadvantage of using these potent opioids is that they can cause clinically significant respiratory depression which is due to their potent effect on mu-opioid receptors. Activation of mu-opioid receptors in the respiratory centres of animals depresses neurons that generate the normal respiratory rhythm. At the same time activation of mu-opioid receptors on chemo receptors in the brain stem, on the aortic arch and carotid bodies depresses the normal respiratory drive as these chemo receptors become less sensitive to activation by hypercapnia, hypoxaemia and acidaemia. This effect in turn leads to a reduction of the respiratory frequency and tidal volume. Furthermore, pulmonary vasoconstriction, caused by the sympathomimetic actions of etorphine, decreases pulmonary perfusion. This effect leads to impaired diffusion of oxygen through the alveolar membrane. Studies have found that serotonergic ligands, specifically 8-hydroxy-2-(di-n-propylamino) tetralin (8-OHDPAT), improved blood oxygenation by reducing opioid-induced respiratory depression and improving pulmonary perfusion through their serotonergic effects on the lungs and brain. More specifically, 8-OH-DPAT binds to 5-HT1A and 5-HT7 serotonin receptors in the lungs and brain. This binding results in smooth muscle relaxation and improved pulmonary perfusion without affecting catatonia and sedation caused by opioids. It was thought that the use of the R-enantiomer of 8-OH-DPAT (R-8-OH-DPAT) in comparison to the racemic form (RS-8-OH-DPAT), might produce even better results because of its high specificity at the 5- HT1A receptors.
Although some literature on the pharmacokinetic data of 8-OH-DPAT in rats and marmosets existed, there was no published literature available on the pharmacokinetics of 8-OH-DPAT in ungulates.
Therefore, the investigation into the pharmacokinetics and bioavailability of R-8-OH-DPAT in goats served as the first step in a series of experiments to understand the viability of adding R-8-OH-DPAT to an opioid-based immobilisation protocol for wild antelope species in order to alleviate respiratory depression. It was hypothesised that the pharmacokinetics and bioavailability of R-8-OH-DPAT in goats would be similar but different to that reported in other species. It was established that the bioavailability of R-8-OH-DPAT when injected intramuscularly (IM) into goats was 66%. At the dosage used in this experiment (0.1 mg kg- 1), signs of serotonin toxicity were observed in some of the goats. The bioavailability results, as well as the encountered side effects in goats, guided the choice of three experimental R-8- OH-DPAT dosages for the next experiment.
The second experiment aimed to determine the ability of R-8-OH-DPAT, when administered in combination with etorphine in a dart, to prevent opioid-induced respiratory depression in blesbok (Damaliscus pygargus phillipsi) and impala (Aepyceros melampus). The experiment also aimed to establish the most clinically effective dosage of R-8-OH-DPAT, in these species.
Blesbok and impala were chosen for the second experiment as they were abundant and readily available in the study area. Both are antelope species commonly immobilised with potent opioids. Impala are regularly used in immobilisation experiments. It was hypothesised that R-8-OH-DPAT would mitigate opioid-induced respiratory depression in wild ungulates without affecting the quality of immobilisation. R-8-OH-DPAT did not influence induction, immobilisation or recovery scores in either of the species. However, this experiment revealed that there were substantial differences between the two antelope species and their physiological changes after the administration of etorphine alone as well as etorphine in combination with 0.005, 0.02 and 0.07 mg kg-1 R-8-OH-DPAT respectively. Surprisingly, opioid-induced hypoxia was substantially more severe in impala compared to blesbok. Respiratory rate in blesbok, but not impala, increased with an increasing dosage of R-8-OHDPAT but this did not translate into clinically relevant improvements in partial arterial oxygen pressure (PaO2) values in blesbok.
In impala, the medium and higher dosages of R-8-OH-DPAT combined with etorphine led to an improved PaO2 and decreased opioid-induced tachycardia during the first ten minutes of immobilisation.
It was concluded that species-specific effects and the possibility of serotonin toxicity at higher dosages, which seemed most effective, might not allow the routine use of R-8-OHDPAT at appropriate dosages for wildlife immobilisation.
These results lead to the third experiment which aimed at comparing physiological effects of two commonly used potent opioids, namely etorphine and thiafentanil, in both antelope species. It was hypothesised that the time to recumbence, immobilisation quality and physiological variables during immobilisation of blesbok and impala respectively would differ between the two potent opioids.
The results of this experiment demonstrate that both opioids used in high dosages are suitable for immobilisation of blesbok and impala without the addition of any sedative or tranquillisers. Both, blesbok and impala developed hypertension with either of the opioids. The thiafentanil treated animals of both species developed higher systemic blood pressure compared to the etorphine treated animals. The healthy animals used for these experiments recovered from hypertension without apparent adverse consequences.
Thiafentanil in impala achieved a faster time to recumbence compared to etorphine but thiafentanil also was responsible for more incidences of prolonged apnoea during the beginning of the monitoring period in impala. Overall, there were large differences in the reaction of individual impalas to the opioid immobilisation, which seemed to result in unpredictable immobilisation.
In blesbok, opioid-induced respiratory depression, hypoxia and hypercapnia were much less pronounced than in impala. Thiafentanil treated blesbok had higher respiratory rates, higher PaO2 and lower partial arterial carbon dioxide pressure (PaCO2) compared to etorphine treated blesbok. There was no difference in time to recumbence between the two opioids in blesbok.
In conclusion, for short term management procedures of impala and blesbok, both opioids are suitable. No matter which opioid is used, both cause hypoxaemia to a greater or lesser degree and oxygen supplementation should be considered for both species.
Veterinarians should also be aware that in some species, such as impala, thiafentanil can achieve a faster time to recumbence than etorphine. However, this statement cannot be applied across all species as in blesbok there was no significant difference between both drugs with regards to time to recumbence. In addition, time to recumbence has to be weighed against potential negative respiratory, pulmonary and cardiovascular side-effects of the drug.
While these experiments did not give the desired positive results with regards to the use of R-8-OH-DPAT to alleviate opioid-induced respiratory depression, they led to insights into differences between the two opioids which will enable veterinarians to make a more educated decision as to which opioid should be used preferentially.
New insights into the differences between blesbok and impala with respect to reaction and physiological changes caused by opioids will also enable researchers to make decisions with regards to species selection for wildlife trials. It may also explain some of the difficulties encountered when immobilising impala.