Dissertations / Theses on the topic 'Polymers in medicine – Testing'
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1
Lu, Yuebin. "Deep penetration microindentation testing of polymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/NQ58147.pdf.
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Mohammad, Muhanad Hassan. "Biodegradable polycaprolactone polymers for regenerative medicine." Thesis, University of Brighton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413097.
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Yu, Jiayi. "Tunable Biodegradable Polymers for Regenerative Medicine." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1524821159786707.
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Klimchuk, Keith Adrian. "Synthesis, characterization, and testing of acrylamide-based polymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0005/MQ34492.pdf.
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C̆yz̆iūtė, Brigita Abakevic̆ienė. "Processes of deposition and testing of mechanical properties of polymers and metal coated polymers." Poitiers, 2008. http://theses.edel.univ-poitiers.fr/theses/2008/Abakeviciene-Cyziute-Brigita/2008-Abakeviciene-Cyziute-Brigita-These.pdf.
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The Ph. D. Work objective was the measurements of the mechanical properties of polymer foils and metal coated polymers, in connection with their microstructures. Two similar micro-tensile deformation devices were developed, which differ by their original non-contact deformation measurement techniques that are electronic speckle pattern interferometry and optical mark-tracking, at the Universities of Kaunas and Poitiers, respectively. The elongation range of both equipments allows for the investigation of elastic and plastic properties of polymer foils, coated polymer foils with thin metallic films. The substrates were either Kapton® HN or PET foils that were coated by electron beam evaporation with Al, Ag, Cr and Ni 0. 5 thick thin films on both sides. The Young’s moduli of the metallic thin films (Ef) were deduced from the stress-strain curves of the substrates and of the metallic/substrate composites. For Al and Ag, the deduced Ef values are in good agreement with those of bulk materials (Eb), while the Ef values for Ni and Cr are found drastically smaller than those of Eb. It was however observed that the Al and Ag metallic layers were uniform, whereas Ni and Cr films were far less regular and exhibit cracks. The microstructures and metal/polymer interfaces were essentially studied on the Ag/PET system. The influence of metal coverage on interface composition, structure, morphology and particle size has been studied by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD). In addition, the role of deposition temperature over the temperature range 20°C-140°C, i. E. Below and above Tg (Tg = 80°C is the PET glass transition temperature), was also examined to understand how microstructure, residual stress, chemical composition and morphology of the Ag/PET layer structure is affected. It was observed that Ag 1 μm thick films evaporated at different temperatures show a compressive stress state with either a (111) texture component below Tg or a random grain orientation above Tg. The texture is formed at the very early stage of growth, at a thickness of nearly 20 nm where the Ag film is still discontinuous. Within the investigated temperature range, the Ag grain size does not depend on the deposition temperature and the deposited films are mostly composed of pure Ag with partially oxidized surfaceLe but de ce travail de thèse était de caractériser, en relation avec leurs microstructures, les propriétés mécaniques de films polymères seuls ou revêtus de films minces de matériaux métalliques. Pour cela, deux micromachines de déformation très similaires ont été développées à l'Université de Kaunas et de Poitiers, qui se différencient par leur technique de mesure de déformation sans contact avec l'échantillon, à savoir respectivement la technique par interférométrie de granularité laser et celle de suivi de marqueurs par corrélation d'images. Les élongations permises par les deux équipements autorisent l'étude de la déformation à la fois élastique et plastique des films polymères et polymères revêtus de films minces métalliques. Les substrats ont été des films de Kapton® HN ou de PET revêtus par évaporation par canon à électrons sur chaque face de films minces de Al, Ag, Cr et Ni de 0. 5 μm d'épaisseur. Les modules d'Young (Ef) des couches métalliques ont été déduits des courbes contrainte-déformation des films polymères seuls et revêtus. Pour les films d'Al et Ag, les valeurs de Ef calculées sont en bon accord avec celles couramment rapportées dans la littérature pour les matériaux massifs (Eb), tandis que pour Ni et Cr les valeurs de Ef sont nettement plus faibles que celles de Eb. Il a été corrélativement observé que les couches d'Al et d'Ag étaient uniformes, tandis que celles de Ni et Cr étaient nettement plus irrégulières et présentaient des fissures. Les microstructures et les interfaces métal/polymère ont été principalement étudiées pour le système Ag/PET. L'influence de la couverture métallique sur la composition de l'interface, sa structure, sa morphologie et la taille des particules a été étudiée par XPS, AFM et XRD. De plus, le rôle de la température de dépôt a été étudié sur une plage allant de 20°C à 140°C, c'est-à-dire en dessous et au-dessus de la température de transition vitreuse, Tg = 80°C pour le PET, afin de comprendre mieux comment la microstructure, les contraintes internes, la composition chimique et la morphologie du système Ag/PET peuvent être influencées. Les films d'Ag de 1μm d'épaisseur évaporés à différentes températures sont en compression, texturés (111) au dessous de Tg et non texturés au dessus. La texturation existe dès le début de la croissance du film, à une épaisseur de 20 nm lorsque le film est encore discontinu. Sur la plage de température étudiée, la taille des grains d'Ag ne dépend pas de la température de déposition et les films déposés sont majoritairement composés d'Ag pur avec une oxydation partielle de surface
6
Shah, Shuhrat. "Testing for disease inheritance." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386800.
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Govender, Ramona. "Anti-neutrophil cytoplasmic antibody (ANCA) testing at Groote Schuur Hospital: Adherence to indications for testing." Master's thesis, Faculty of Health Sciences, 2021. http://hdl.handle.net/11427/33700.
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Appropriate use of laboratory investigations is increasingly important in resource-constrained environments. We receive the anti-neutrophil cytoplasmic antibody (ANCA) testing practices in a tertiary hospital in South Africa.
8
Clarke, C. G. "The sliding wear of polymers against steel." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/22007.
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Bibliography: pages 89-93.A laboratory wear testing facility has been developed to generate wear rate data for polymeric materials sliding at constant velocity against a hardened stainless steel base. The polymers investigated were ultra high molecular weight polyethylene (UHMWPE), ultra high molecular weight polyethylene-with a friction reducing additive (UHMWPE/FILL), polyoxymethylene (POM), poly(ethylene terephthalate) (PETP), molybdenum disulphide filled polyamide 6 (PA6/MoS₂) and graphite filled poly(amide-imide) (P(A-I)/GR). Testing was carried out as a function of sliding velocity between 0.13 to 2.27 ms⁻¹, loads of 1, 3 and 5 MP a and counterface roughnesses which varied from 1 micrometre to 0.25 micrometres. An increase in the counterface roughness resulted in a variable increase in the wear rate of the individual polymers except for the filled UHMWPE. These changes in the wear rate have been explained in terms of the mechanism of material removal. A progressive increase in sliding velocity has been shown to result in an initial increase in the wear rate followed by a decrease and finally a rapid increase for all materials under the majority of applied conditions. Explanations for such behaviour have been advanced in terms of the viscoelastic response of the polymers to strain rate and temperature. Low modulus materials however showed a significant drop in wear rate under low loads above a critical velocity which is believed to be due to a transition from boundary to partial el astohydrodynamic lubrication. Generally an increase in load gave an increase in wear rate for all polymers except for UHMWPE and filled UHMWPE at a counterface roughness of 1 micrometre. These conditions have been discussed with reference to the materials response to thermal effects and counterface interactions.
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Marnock, Patrick J. (Patrick Joseph). "Development of a Simplified Fracture Toughness Tool for Polymers." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc278473/.
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This thesis presents research toward the development of a simple inexpensive fracture toughness tool for polymeric materials. Experiments were conducted to test the specimen configuration and the fracture toughness tool against an established ASTM standard for polymer fracture toughness, D5045, and a commonly used four-point bend method. The materials used in this study were polycarbonate and high density polyethylene. Reductions in both the production time and the variability resulting from the preparation of the specimens were addressed through the use of specially designed fixtures. The effects from the razor cut depths used in the chevron notch were compared to the fracture toughness values obtained in order to determine the effect upon the validity of the fracture toughness.
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Cetin, Mustafa Ilker. "Effect Of Solid Couplants Made Of Hydrophilic Polymers In Ultrasonic Testing." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/3/1223106/index.pdf.
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This thesis investigates the effect of hydrophilic polymers as novel solid couplants in ultrasonic inspection. These polymers can absorb large quantities of water, thus become soft and flexible, and also adapt themselves very well to applications. In this study, experiments were carried out by preparing three different types of polymer membranes namely [Poly(HEMA), Poly(HEMA-co-GMA), Poly(HEMA-NN′
-dH2O)] with different thicknesses and monomer contents. Swelling ratios were determined in deionized water using 9mm diameter samples, cut from each polymer. Ultrasonic velocity and sound attenuation measurements were performed with pulse-echo and immersion techniques. These results were analyzed and compared with water, typical plastics and rubbers. In order to evaluate the coupling performance of hydrophilic polymers, weights of 50g, 200g, 500g and 1 kg were used as loading conditions to change the pressure applied to the transducer. Results obtained with this study showed that hydrophilic polymers offer low attenuation at high frequencies and couple effectively while eliminating the risk of test piece contamination. The study also revealed that velocities of polymers decrease by increasing the water content. This research can be used as a guideline for an alternative choice of couplant while testing water sensitive materials in safety critical structures or where the test piece is avoided from contamination and also can be used for rough surfaces.
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Oz, Saba. "Usability Testing Of A Family Medicine Information System." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614716/index.pdf.
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Healthcare is an important part of life in most societies that attract a significant amount of public investment. Primary healthcare is a fundamental branch of the healthcare system where patients and doctors initially meet. Family Medicine Information Systems are developed in an effort to ease the daily work of family doctors with the help of information technology. Such systems are generally used for handling critical tasks such as managing health records of patients, monitoring pregnancy and keeping track of children&rsquos vaccination. Like any medical information technology, the usability of such systems is a vital concern for enabling efficient and effective primary healthcare operations. Family Medicine is a recently established practice in Turkey and there are a number of systems in service to aid the daily work of family doctors. However, none of these systems have been subjected to a systematic usability analysis. In this study, a usability analysis of a popular Family Medicine Information System used in Turkey is conducted. By combining several usability evaluation techniques, the study identified several important usability issues and provided recommendations for further improving the system. The main usability issue observed in the system was the overall complexity of the information presented at the main interface that often confused and misled the users. In order to address this problem, it is suggested that features related to the most frequent family medicine operations should be placed on the main screen, whereas remaining features should be organized under auxiliary pages with clear navigation aids.
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Steggles, Naomi. "Psychological aspects of genetic testing for cancer." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271020.
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Chen, Zhaoyu [Verfasser]. "Nanoindentation testing of soft polymers : Computation, experiments and parameters identification / Zhaoyu Chen." Aachen : Shaker, 2014. http://d-nb.info/1053903243/34.
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Forrester, Hsuan-Hsiou. "High strain rate compression testing of polymers : PTFE, PCTFE, PVC and PMMA." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/13624.
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The mechanically compressive flow stress sensitivities of various polymers are investigated at high strain rates above 103 s-1. Temperatures near the glass transition temperature are investigated and the polymer stress-strain responses have been studied from ambient temperature to 100°C. Previous work has reported peaks in flow stress as a function of strain rate [Al-Maliky/Parry 1994, Al-Maliky 1997]. The analyses showed rapid increases of flow stress followed by a sudden drop at elevated strain rates, which is unlike the well known linear relationship documented at the low strain rates. The mechanics and stipulation of what bring about this phenomenon, or the types of polymers influenced are still unclear. Two fluoropolymers, polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE), and two vinyl polymers, polyvinylchloride (PVC) and polymethylmethacrylate (PMMA), are chosen for this study. PTFE, PCTFE and PVC are semi-crystalline polymers with different percentage of crystallinity contents, whereas PMMA is an amorphous polymer. The glass transition temperature, Tg, is the characteristic of the amorphous content in polymers, which has been suggested to influence the flow stress peaks [Swallowe/Lee 2003]. Tg of the semi-crystalline polymers are within the test temperature range. High strain rate compression tests have been carried out using the split Hopkinson pressure bar (SHPB). This is a well-established method for determining the stress, strain, and strain rate of materials. The strain rate range of interest is 103 s-1 to 105 s-1 where the strain rate sensitivity has previously been identified [Al-Maliky/Parry 1994, Al-Maliky 1997, Walley/Field 1994]. Two thermal analyses techniques are used to quantify the dependency of the viscoelastic behaviour in relation to time and temperature. Differential scanning calorimetry (DSC) measures the enthalpy of the polymers to show how the materials are affected by heat, and Dynamic mechanical analysis (DMA) is used to characterise the time-temperature dependence of the elastic storage and loss moduli of the polymers A total of 42 PCTFE, 44 PTFE, 45 PVC and 55 PMMA specimens were tested using the SHPB system, with the strain rate varying between 1600 s-1 and 6100 s-1. Initial results for PMMA have been reported [Forrester/Swallowe 2009]. The rate of strain where specimens begin to show crazing is identified. The value of yield stress increases with the increase of strain rate and the decrease in temperature. Large strain hardening can be seen in all three semi-crystalline polymers at higher strain rates. The temperature rise during plastic flow of compression is calculated by the stress-strain rate curves. In this thesis, the emphasis is on the relation of yield/flow stress to strain rate as the polymers deform under high strain compression. The mechanism behind the cause of high strain rate deformation responses for amorphous to semi-crystalline polymers in ductile state is discussed, with a view to understanding the sensitivity of yield/flow stresses as a function of strain rate. Also, the modelling of the polymers has been carried in order to alleviate doubts about the validity of the real experimental results that may arise due to the nature of the decomposition of the polymers. It has been shown that the strain energy density pulses through the sample in response to the compression wave in various circular intensities.
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Yoo, Jun. "Synthesis of new biodegradable polysulfenamides for applications in medicine." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1114.
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The first polysulfenamides were synthesized with S-N and N-S-N bonds along the backbone. We demonstrated that sulfenamides were stable in polar protic and aprotic solvents, but degraded rapidly when exposed to acidic conditions. Microparticles were fabricated from polysulfenamides with S-N bonds, their surfaces were readily functionalized, and they were internalized by cells allowing for intracellular delivery of their cargo. These microparticles were also stable at physiological pH, degraded under acidic conditions, and possessed minimal toxicity towards cells. This work demonstrated that polysulfenamides form the basis for a new set of polymers for drug delivery that greatly differ from prior work in this field.
New biodegradable polymers with N-S-N bonds along the backbone were synthesized. These were the first polymers with these bonds and possessed many of the same characteristics as polymers synthesized with S-N bonds.
The synthesis and characterization of comb block copolymers with arms composed of poly(lactic acid), poly(butyl acrylate), and poly(styrene-b-vinylpyridine) were described. The self-assembled morphologies in the solid state of comb tri- and tetrablock copolymers with poly(styrene) were also described. These assemblies demonstrated that well-ordered and complex morphologies were assembled from these polymers.
The steric effect of substitutions on oxanorbornenes in ring opening metathesis polymerization (ROMP) was investigated. Oxanorbornenes substituted with methyls at the bridgehead positions showed limited reactivity with the Grubbs first and second generation catalysts and the Grubbs first generation methylidene catalyst.
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Saunders, John Michael. "Optimising opportunities for STI testing for men : exploring the acceptability of different testing venues with a focus on football club-based testing." Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8467.
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Background: Chlamydia trachomatis is the commonest curable sexually transmitted infection in the UK. The prevalence is shared equally by men and women. A National Chlamydia Screening Programme (NCSP) has been introduced in England, supported by advances in testing technologies which enable non-invasive sampling methods to be used in non-healthcare settings. The NCSP tests nearly twice as many women as men and is more likely to test men in non-healthcare settings. Men are seen as an important, but difficult to reach group. Little is known about where men prefer to access testing and whether or not nontraditional settings, such as football clubs, are acceptable. Methods: 1) A national stratified random probability sample survey of men aged between 18 and 35 years resident in Great Britain, exploring attitudes to self-collected testing for Chlamydia, acceptability of venues to collect testing kits, health seeking and sexual risk behaviours. 2) Qualitative interviews with men who play amateur football. It explores the acceptability of three different, club-based, testing pathways; Health-care professional promoted; Peer-led promoted; and poster-led promoted. Results: Men are well engaged with existing health services and find selfcollected testing kits for Chlamydia highly acceptable. Healthcare settings are the most acceptable venues to access testing although sports settings are acceptable to a minority. Attitudes to testing in football clubs are influenced by factors relating to men’s characteristics, promoter characteristics and the impact of testing on time and effort involved. Conclusions: Whilst non-healthcare settings can be used to reach some men for Chlamydia testing, existing services are already well accessed and offer considerable opportunities to test more men. More should be done to ensure men are able to access testing within the context of daily living, without significantly impacting on the time needed to pursue their main interests.
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Dobashi, Yuta. "Characterization of ionic polymers : towards applications as soft sensors in medicine." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59565.
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A phenomenon termed the piezoionic effect is described and characterized in various ionic polymers including polymer networks containing aqueous electrolytes (hydrogels) and organic electrolytes. Initial observations suggest that when an ion containing polymer is compressed, a concentration gradient is induced by the pressure differential, leading to an electrical potential difference detectable at electrodes placed at compressed and uncompressed portions of the polymer. The work focuses on the fundamental characterization of the nature of the piezoionic transduction to probe the effects of relative mobilities of the ions present in the system. The effective ion radii due to ion-solvent interactions and electrostatic ion-polymer interactions have been investigated for their contribution in dictating the piezoionic behavior by NMR measurements of the self-diffusion coefficients. The results are qualitatively correlated to the voltage response to mechanical compression of the polymer samples. Following the experiments, a numerical model is developed which incorporates a number of contributing events believed to be taking place in a concerted manner to cause the piezoionic effect. The deformation induced solvent flow is modeled by means of Biot’s constitutive equations on poroelasticity, a combination of thermodynamic equilibrium and Darcy’s law. The Darcy’s flow induced is then used as the input to model transport of dilute species. Here, the convective factor is being continuously modulated by Darcy’s flow, while Fickian diffusion concurrently takes place. The ionic species experience different displacements due to Stokes' drag experienced by the solvation spheres of the ionic species and solvent molecules and the electrostatic interactions between the charged polymer chains and the mobile ions. Furthermore, this non-homogeneous ionic charge distribution yields a voltage distribution via the Poisson’s equation. This voltage distribution is used to account for the migration of ionic species. The following chapter is dedicated to a novel electrochemical method and modelling approach designed to probe various ionic polymers, some electronically conductive and others interpenetrated, to determine the phase-wise contributions to ionic conductivities. Finally, potential applications of the piezoionic polymers as soft sensors in medicine, particularly in unobtrusive and longitudinal monitoring of physical parameters, are discussed and some preliminary prototypes are introduced and ultimate feasibility is assessed.Applied Science, Faculty of
Graduate
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Diacon, Aurel. "Polymers functionalized with chromophores for applications in photovoltaics, photonics and medicine." Angers, 2011. https://tel.archives-ouvertes.fr/tel-00976715.
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La thèse intitulée "Polymères fonctionnalisés avec des chromophores pour des applications en photovoltaïque, photonique et médecine" est structurée en trois chapitres portant sur: a) l'obtention de chromophores et de nouveaux matériaux pour les cellules solaires à base de colorant; b) l'obtention de dérivés de fullerène C60 présentant une absorption élevée; c) l'obtention d'une plateforme permettant la fixation d'une antenne collectrice de lumière PDI-C60 intégrant un groupe fonctionnel libre réactif; d) l'obtention des cristaux photoniques polymères et leur utilisation dans la modification des émissions du colorant et la construction d'hétérostructures complexes intégrant ces colorants. Dans le premier chapitre sont présentés des nouveaux matériaux pour cellules solaires à base de colorant en vue de construire des cellules solaires à l'état solide en utilisant des polymères pour remplacer l'électrolyte liquide. Des stratégies pour améliorer l'efficacité des cellules en utilisant un colorant qui présente une meilleure capacité d'ancrage à la couche de TiO2, et l'utilisation des quantum dots particules pour l'augmentation du taux d'injection d'électrons ont été testées. Dans le deuxième chapitre est présentée l'obtention des nouvelles antennes collectrices de lumière à base de fullerène. Des adduits fullerènes phtalocyanine ont été obtenus et le transfert d'électrons a été prouvé par spectroscopie de fluorescence. Une dyade PDI-C60 a été attachée avec succès sur une chaîne de polymère pour augmenter la processabilité afin d'envisager des applications dans les cellules solaires organiques. Dans le troisième chapitre ont été analysées les propriétés optiques des cristaux photoniques et d'hétérostructures complexes modifiées aves des colorantsThe thesis entitled "Polymers functionalized with chromophores for applications in photovoltaics, photonics and medicine" is structured in three chapters dealing with: a) the obtaining of chromophores and new materials for dye-sensitized solar cells; b) the obtaining of new fullerene-C60 derivatives with increased absorption; c) the obtaining of a platform allowing the attachment of lightharvesting dyads PDI-C60 including a free functional group for further applied developments of which one consisting in grafting onto a polymeric chain for increased processability; d) the obtaining of polymer photonic crystals and the utilization in dye emission modification and the building of complex heterostructures with chemosensor capabilities. In the first chapter new materials for hybrid dye-sensitized solar cells are presented with the aim of constructing solid state solar cells using polymers to replace the liquid electrolyte. Furthermore, strategies for improving the cell efficiency by using a dye with better anchoring on the TiO2 layer capacity, and the use of quantum-dots particles for the increasing of the electron injection rate have been tested. In the second chapter the obtaining of new fullerene based light-harvesting antennas is presented. Fullerene-phthalocyanine adducts were obtained and electron transfer was proven through fluorescence spectroscopy. A PDI-C60 dyad was successfully attached onto a polymeric chain for increasing processability for applications in bulk-heterojunction solar cells. In the third chapter the optical properties and use as chemosensor of polymer photonic crystals and complex heterostructures modified with fluorescent dyes was investigated
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Ramrus, Daniel A. "The creation and adhesion testing of patterned silane surfaces /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/9838.
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Shahi, Sandeep Kaur. "The synthesis and testing of fast switching, novel conjugated polymers for electrochromic applications." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28503.
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Modern technology is an essential aspect of our everyday lifestyle being vitally important to lighting, mobile phones, laptops, toys etc. The majority of these gadgets concentrate on visual electronic displays as a key selling feature. Hence, industry is in constant competition to excel while delivering new consumer demands of higher colouration efficiency, faster response times, inexpensive yet robust hardware, flexible displays and with the possibility of incorporating electronics into textiles. Traditionally, inorganic small molecules were extensively used for optical displays devices such as cathode ray tubes, liquid crystal displays, light emitting diiodes [sic] and plasma screens. However, in the past decade, significant progress in polymer electrochromism has shown many organic electroactive polymers to have the potential to satisfy the above consumer demands. Electrochromic materials (EC) have the ability to undergo a reversible colour transformation switch upon electrochemical doping, such as colour bleaching transformations. Herein, this thesis discusses how organic chemistry facilitates the advantage of structurally modifying monomeric heterocyclics to fine tune materials with interesting optical and physical properties. The polymeric form of an teraryl monomer containing a 1,4-dithiin-furan illustrated superior switching performances and electrochromic properties when compared to its parent poly 3,4-ethylene dioxythiophene (PEDOT). Poly(dithienylfuran) films displayed fast switching and reversible colour transformation at high colour contrast (CE = 212 cm2 C-1 cf. 183 cm2 C_1 for PEDOT at 95% optical switch). Formerly overlooked furan materials in organic electronics was revisted here, in which a polyfuran substituted at the 2,3-positions with an S-alkylated dithiin unit, was studied. The employment of the dithiin moiety provides intrinsic additional electroactivity, as well as a functional handle for substitution with alkyl groups, enhancing the processability of the polymer. The new polymer is compared with the closely related and well-established literature compounds PEDOT and PEDTT as well-studied, highly chalcogenated polythiophenes. The electrochromism phenomenon is not only of importance for visual optical displays but also has the potential for extended application in telecommunications with electromagnetic responses into the near infra-red (NIR) region. Herein, describe a series of symmetric and asymmetric chalcogenated azomethine monomers, robustly exherting electrochemical activity within the NIR.
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Yeakle, Colin. "Experimental Testing and Numerical Modeling to Capture Deformation Phenomenon in Medical Grade Polymers." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1313771863.
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Bergenström, Anne Maarit. "HIV testing and prevention for women of reproductive age." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271474.
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Luo, Shijian. "Synthesis and charaterization of chiral 2-methyl-1,4-cyclohexanedicarboxylic acid and its polyamide." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8606.
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Lawson, Joseph L. "On the determination of the elastic properties of geopolymeric materials using non-destructive ultrasonic techniques /." Online version of thesis, 2008. http://hdl.handle.net/1850/7356.
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Hagg, Lobland Haley E. "Definition of Brittleness: Connections Between Mechanical and Tribological Properties of Polymers." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9097/.
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The increasing use of polymer-based materials (PBMs) across all types of industry has not been matched by sufficient improvements in understanding of polymer tribology: friction, wear, and lubrication. Further, viscoelasticity of PBMs complicates characterization of their behavior. Using data from micro-scratch testing, it was determined that viscoelastic recovery (healing) in sliding wear is independent of the indenter force within a defined range of load values. Strain hardening in sliding wear was observed for all materials-including polymers and composites with a wide variety of chemical structures-with the exception of polystyrene (PS). The healing in sliding wear was connected to free volume in polymers by using pressure-volume-temperature (P-V-T) results and the Hartmann equation of state. A linear relationship was found for all polymers studied with again the exception of PS. The exceptional behavior of PS has been attributed qualitatively to brittleness. In pursuit of a precise description of such, a quantitative definition of brittleness has been defined in terms of the elongation at break and storage modulus-a combination of parameters derived from both static and dynamic mechanical testing. Furthermore, a relationship between sliding wear recovery and brittleness for all PBMs including PS is demonstrated. The definition of brittleness may be used as a design criterion in selecting PBMs for specific applications, while the connection to free volume improves also predictability of wear behavior.
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Damarla, Gowrisankar. "Determination of Wear in Polymers Using Multiple Scratch Test." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4627/.
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Wear is an important phenomenon that occurs in all the polymer applications in one form or the other. However, important links between materials properties and wear remain illusive. Thus optimization of material properties requires proper understanding of polymer properties. Studies to date have typically lacked systematic approach to all polymers and wear test developed are specific to some polymer classes. In this thesis, different classes of polymers are selected and an attempt is made to use multiple scratch test to define wear and to create a universal test procedure that can be employed to most of the polymers. In each of the materials studied, the scratch penetration depth s reaches a constant value after certain number of scratches depending upon the polymer and its properties. Variations in test parameters like load and speed are also studied in detail to understand the behavior of polymers and under different conditions. Apart from polystyrene, all the other polymers studied under multiple scratch test reached asymptotes at different scratch numbers.
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Lu, Yuebin. "The application of microindentation testing to measure the inhomogeneity of mechanical properties in polymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/MQ42243.pdf.
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Wadlow, Philip James. "MATERIAL SELECTION AND TESTING FOR A RADIATION THERAPY CATHETER." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1661.
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Three different polymers (a high-density polymer and two other polymers) were tested for use as an x-ray catheter in a radiation therapy application. This report describes the testing of these three materials to determine which material is the best option for a long use catheter. Tests included tensile, simulated clinical life, and other tests. Some testing was performed using nitrogen and an industrial coolant. Testing revealed significant non-circularities for some catheters. With increasing pressure, the circularity of these catheters increased. The tensile tests were performed on samples with varying doses of radiation. Tensile testing showed significant decreases in ultimate tensile strength with increasing radiation dose for both polyurethanes. Other testing was performed on the two polyurethanes to determine their compatibility with the industrial coolant. The test showed good compatibility with the coolant. Simulated clinical life tests were performed on a test fixture and with software to run the radiation source automatically for several hours at a time. Overall, one material was found to have very low ductility, made lower with increasing radiation. The material with the higher ductility was chosen as the better catheter material despite some disadvantages when compared to the stiffer polymer. This report describes necessary tests for thin polymer geometries used in applications where resistance to radiation, mechanical integrity, and coolant compatibility are the main considerations.
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Bevilacqua, Elisa. "Non-invasive prenatal testing: a new era in fetal medicine." Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/304668.
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Les anomalies chromosomiques sont une cause majeure de morbidité et de mortalité périnatales. Le dépistage de ces affections a toujours été crucial pour une prise en charge optimale des femmes enceintes.Initialement, le dépistage de trisomie 21 était uniquement basé selon le risque lié à l’âge maternel. L’ajout de différents marqueurs biochimiques sériques constituant successivement les double, triple et quadruple tests a pu améliorer le taux de détection. Néanmoins, c’est en 1997 qu’apparaît un point tournant de l’histoire de dépistage des trisomies :l’introduction de la mesure de la clarté nucale à l’échographie du premier trimestre.Depuis 2011, de nouvelles recherches se sont concentrées sur le dépistage prénatal non invasif (DPNI) utilisant l'ADN fœtal libre circulant dans le sang maternel. Cette technique a suggéré directement une supériorité marquée pour la détection de la trisomie 21 comparée à toutes les autres méthodes de dépistage connues. Rapidement, ce test a été introduit en pratique clinique dans le monde entier sans une évaluation préalable et approfondie, que ce soit au niveau scientifique, technique ou éthique.Les objectifs de cette thèse étaient de fournir des réponses aux diverses questions persistantes concernant l’utilisation clinique des tests de dépistages basés sur ADN fœtal libre dans la circulation maternelle.À notre connaissance, nous sommes la première équipe à essayer d'évaluer le taux d'échec et la performance du DPNI effectué par différents laboratoires utilisant différentes méthodes analytiques. Nous avons démontré que les approches « DANSR » (approche ciblée sur les chromosomes d’intérêt) et « GW-MPS » (approche globale sur les séquences géniques reparties sur la totalité du génome par un séquençage à haut débit) offraient toutes les deux un taux échec bas avec une bonne performance dans la détection des trisomies 21, 13 et 18. Cependant, le niveau de fraction fœtale semble varier d'un laboratoire à l'autre et n’est, par conséquent, pas comparable. Nous avons également observé que le taux d'échec des laboratoires avec un test « home-brew » était 4 fois supérieur à celui des tests commerciaux développés par les laboratoires en interne. De plus, aucune pertinence clinique de la divulgation des aneuploïdies autres que les 3 trisomies communes décelées par les DPNI « GW-MPS » n’a pu être démontrée.Ensuite, nous nous sommes intéressés au groupe particulier des grossesses gémellaires. Dans ce groupe, le DPNI était faisable mais il était associé à un taux d'échec supérieur aux grossesses uniques, tout en fournissant un taux de détection moindre des trisomies communes. Un poids maternel élevé et la conception par fécondation in vitro étaient des facteurs indépendants associés à l’échec du test. De plus, il faut souligner l’importance de développer des normes de contrôle de qualité pour les analyses faites sur l’ADN fœtal libre. Nous avons aussi étudié les modifications de l’ADN fœtal libre après une mort fœtale en raison d’une aneuploïdie chez l’un des deux fœtus lors d’une grossesse gémellaire. Après le décès du fœtus atteint, la fraction fœtale de l’ADN libre circulant dans le sang maternel a montré une évolution imprévisible, pouvant augmenter, diminuer ou rester stable dans le temps. Par conséquent, ces résultats déconseillent l’utilisation du DPNI en cas de décès d’un des deux fœtus, même après un intervalle de temps de plusieurs semaines.Notre attention s’est ensuite portée vers la performance du DPNI pour le dépistage des anomalies autres que les 3 trisomies communes. Nous avons d’abord étudié la performance du DPNI pour les anomalies des chromosomes sexuels ainsi que les caractéristiques des patientes optant pour ce test. Plus de la moitié des patientes ayant eu un DPNI ont également souhaité le dépistage des anomalies des chromosomes sexuels. Les valeurs prédictives positives suivantes ont été observées :24% pour 45 X et 47 XXX et environ 71% pour 47 XXY et 47 XYY. Ainsi, la recherche d’anomalies des chromosomes sexuels peut causer la détection accidentelle d’anomalies chromosomiques sans conséquence clinique. Par conséquent, un conseil génétique est obligatoire dans toutes ces situations, de même qu’un examen invasif pour un caryotype fœtal de confirmation.Ensuite, nous avons montré que le test à ADN fœtal libre utilisant une technologie ciblée basée sur le microarray permettait d'identifier les grossesses à risque accru de délétions 22q11.2. Cependant, des données fiables sur les performances du DPNI pour le syndrome 22q11.2 sont encore manquantes, et des recherches plus poussées sont nécessaires. Depuis 2015, nous participons à une étude prospective, multicentrique et en aveugle, qui évalue cliniquement un test d’ADN fœtal libre pour la détection de délétions ou de duplications dans la région 22q11. Le recrutement s’est terminé le 1er novembre 2019.Enfin, en décrivant le profil et le choix des patientes belges soumises à un test à ADN fœtal libre, nous avons observé un changement vers une population à faible risque, ce qui peut entrainer une réduction de la valeur prédictive positive du test. Il est donc primordial que cet effet soit connu des professionnels de la santé qui conseillent, prescrivent et interprètent ces tests.En conclusion, notre recherche a démontré la complexité des tests à ADN fœtal libre circulant dans le sang maternel, non seulement du point de vue technique, mais également en termes de conseils aux patients avant et après le test, ce qui requière des connaissances et compétences spécifiques des médecins proposant ces tests.L’ère du test à ADN fœtal libre circulant dans le sang maternel n’en est qu’à ses débuts. Notre travail n’a exploré qu’une petite partie de l’énorme potentiel de ce nouvel outil de dépistage des aneuploïdies.L’intégration responsable des innovations dans la pratique clinique reste, aujourd’hui, l’un des défis majeurs.Doctorat en Sciences médicales (Médecine)
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Lewis, Christopher James. "Quantifying the effects of aging on the mecahnical properties of medical grade polycarbonate and UV cured adhesives /." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd571.pdf.
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Blizard, Kent G. "A study of processing methods for producing biaxial orientation in thermotropic liquid crystalline polymers." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/54318.
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Four methods of biaxial deformation were considered in an attempt to obtain biaxial orientation and properties in two thermotropic copolyesters: hydroxybenzoic acid-co-polyethylene terephthalate (HBA/PET) and hydroxybenzoic acid/2, 6 hydroxynaphthoic acid (HBA/HNA). They consisted of solid phase forming, extrusion blow molding, biaxial stretching, and film blowing. Some measure of biaxial properties and orientation was obtainable in all four processes, from the layered structure apparent in the blow molded bottles to the uniplanar orientation in the stretched film. Tensile and flexural properties were exceptional in the blown film in comparison to the other processes considered: tensile strengths of 300 to 400 MPa and moduli of 13 GPa were observed in the axial direction, for example. This result is believed due to the absence of a skin-core texture in which the core often remains relatively unoriented.
A second objective of this work was to determine the feasibility of using Doi's theory for anisotropic solutions of rigid rods to predict the structure developed during the deformation processes for these thermotropic systems. Doi's theory of nematics, although limited to monodomains and containing numerous mathematical approximations in order to obtain a closed form for the kinetic equation, was used to predict the orientation development in the blown film process. Although qualitative agreement with experiment was found, quantitative agreement could not be expected.
Since Doi's theory was developed by examining an isolated rigid rod in solution and modifying the resultant equations to account for interactions of neighbors, transient predictions on a lyotropic solution were also made and compared to experimental results. In particular, stress growth on the inception of a steady simple shear flow was examined for the system of poly(p-phenylene terephthalamide)/ 100% sulfuric acid. Comparisons to Doi's theory were made for both isotropic and anisotropic solutions. Quantitatively the theory was found to be unacceptable, particularly at higher shear rates in which the equilibrium stress was at least an order of magnitude lower than experimental results showed. It did, however, predict an overshoot in the shear stress, which increases with deformation rate.Ph. D.
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Kellar, Robert Shawn. "Tissue-engineered polymers stimulate angiogenesis in infarcted myocardium." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279837.
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The development and maintenance of a vascular network is critical to the growth and survival of a tissue and ultimately an organism. An understanding of the mechanisms which regulate angiogenesis within and surrounding currently used polymeric devices would contribute to the success of these implants by establishing methods to enhance tissue in-growth and new vessel development. Furthermore, tissue-engineering currently used polymers such as expanded polytetrafluoroethylene (ePTFE) may create an angiogenic material that can be used to induce new microvessel formation in infarcted myocardium. Myocardial infarcts represent a pathology that affects a large percentage of the patient population who suffer from coronary heart disease. Disease of the coronary vasculature can lead to narrowing of the coronary vasculature and result in regions of ischemia which can progress to infarction. Studies in this dissertation evaluate two different tissue-engineered polymer constructs for their ability to stimulate a new collateral network in infarcted myocardium. The results from these studies indicate that the tissue site of implantation is an important factor in influencing the healing response. Therefore, it is important to evaluate future polymer devices in tissues where the device will ultimately reside. Additionally, the physical and chemical characteristics of polymers were found to have a significant influence on the healing response. Furthermore, tissue-engineered polymer constructs stimulated a significant angiogenic response within infarcted myocardium. Tissue-engineered constructs that secreted soluble angiogenic agents were found to have the greatest depth of angiogenic effect into infarcted myocardium leading to the formation of arterioles, capillaries, and venules. Additionally, hearts treated with these devices demonstrated significantly greater left ventricular function in comparison to infarct-only hearts. Based on this work, it is apparent that tissue-engineered polymer constructs may have a future role as cardiac patches and thus provide the patient population with an additional therapy to revascularize infarcted cardiac tissues.
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Babb, Chantal Louiza. "Identification of candidate genes and testing for association with tuberculosis in humans." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/21524.
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Dissertation (PhD)--Stellenbosch University, 2007.ENGLISH ABSTRACT: This research investigated human candidate genes for susceptibility to tuberculosis and the effect of various factors on time to sputum conversion in the admixed South African Coloured (SAC) population. Population stratification was formally tested and excluded. Population based casecontrol studies were the primary analysis method with a variety of genotyping methods. Candidate polymorphisms in RANTES, CCR5, CCR2 and SDF1, were not associated with tuberculosis susceptibility. Initially the RANTES polymorphism -403 was found to be associated with tuberculosis susceptibility but after the testing of additional samples the association was lost, illustrating the challenges with association studies. The C-type lectins DC-SIGN, encoded by the gene CD209, and L-SIGN are important pathogen-recognition receptors of the human innate immune response. Both lectins have been shown to interact with Mycobacterium tuberculosis. CD209 promoter polymorphisms, -336 and - 871, were both found to be associated with tuberculosis susceptibility. The haplotype containing CD209 -871G and -336A was strongly associated with the control group. The CD209 -336A allele has been found to be associated with increased DC-SIGN expression, which may be the underlying reason for an increased efficiency of host phagocytes. Susceptibility to tuberculosis in mice has recently been attributed to the Ipr1 gene. Eight polymorphisms in the human homologue, SP110, were investigated, including two novel polymorphisms. No significant associations were found with any of the polymorphisms investigated, including two polymorphisms that were previously found to be associated with tuberculosis susceptibility in West African populations. A cohort of 249 cases from a longitudinal study of first time pulmonary tuberculosis patients was available. The cohort was used to investigate if the vitamin D receptor gene (VDR) polymorphisms FokI, ApaI and TaqI were associated with tuberculosis susceptibility or time to sputum conversion, and to investigate other clinical and demographic factors affecting the rate of response to treatment. No association between the VDR genotype and tuberculosis was found in the case-control study. The cohort allowed for a reliable conversion time to be determined for smear (n=220) and culture (n=222). Analysis was carried out to determine which factors, including VDR FokI, ApaI, and TaqI genotypes, contribute to faster mycobacterial resolution in sputum. This was done by survival curves and Cox regression models. The results indicate that the extent of disease at diagnosis was predictive of both smear and culture conversion times in the final models. Smoking status and VDR genotype contributed independently to smear conversion time, with ApaI ‘AA’ and TaqI ‘T’ containing genotypes being predictive of a faster response to tuberculosis therapy. We can conclude that the time taken for an individual to convert to sputum negativity while on DOTS therapy, can be independently predicted by the VDR genotype. This may have implications for future immunomodulatory therapies. Identifying what contributes to susceptibility to tuberculosis will provide us with a better understanding of the human immune response to tuberculosis which may lead to the development of accurately targeted therapeutics and vaccines.
AFRIKAANSE OPSOMMING: Kandidaatgene vir die vatbaarheid vir tuberkulose en die effek van verskeie faktore op sputum oorgangstyd was in hierdie navorsingsstudie ondersoek in die Suid-Afrikaanse Kleurlingbevolking (SAC). Dié bevolking was ook getoets vir populasie-stratifikasie, waarvan daar geen bewyse gevind is nie. Populasiegebaseerde pasiënt-kontrole studies was die primêre metode van analise en verskeie genotipering metodes was gebruik. Polimorfismes in kandidaatgene soos RANTES, CCR5, CCR2 en SDF1 was nie met die vatbaarheid van tuberkulose geassosieer nie. Oorspronklik was daar ‘n assosiasie met die RANTES -403 polimorfisme, maar met die genotipering van addisionele individue het die assosiasie verdwyn. Resultate verkry vir die polimorfisme illustreer die uitdagings waaraan assosiasie studies onderworpe is. Die C-tipe lektiene DC-SIGN, wat gekodeer word deur CD209, en L-SIGN is belangrike patogeen herkenningsreseptore in die aangebore immuunreaksie. Interaksies tussen beide lektiene en Mycobacterium tuberculosis is voorheen gerapporteer. Die CD209 promoter polimorfismes, -336 en -871, was met die vatbaarheid van tuberkulose geassosieer. ‘n Haplotipe bestaande uit die CD209 -871G en -336A allele was sterk met die kontrole groep geassosieer. Die CD209 -336A alleel was geassosieer met ‘n toename in die DC-SIGN proteïen vlakke, wat moontlik ‘n onderliggende rede is vir die toename in die effektiwiteit van die gasheer se fagosiete. Vatbaarheid vir tuberkulose is onlangs toegeskryf aan die Ipr1 geen in muise. Agt polimorfismes, insluitend 2 voorheen onbekendes, was in die mens homoloog SP110 bestudeer. Geen positiewe beduidende assosiasie was met enige van die polimorfismes gevind nie ten spyte van die feit dat twee van hierdie polimorfismes voorheen met tuberkulose vatbaarheid geassosieer was in bevolkings van Wes-Afrika. ‘n Versameling van 249 TB pasiënte van ‘n longitudinale studie was beskikbaar. Dié groep was gebruik om polimorfismes FokI, ApaI and TaqI in die vitamien D reseptor geen (VDR) te bestudeer ten opsigte van vatbaarheid vir tuberkulose of sputum oorgangstyd sowel as ander kliniese en demografiese faktore wat die tempo van respons op behandeling kan affekteer. In hierdie studie was daar geen assosiasie gevind tussen die ontwikkeling van tuberkulose en die VDR genotipes nie. Die bepaling van ‘n betroubare oorgangstyd vir beide smeer en kultuur van die groep was moontlik. Analises was uitgevoer om te bepaal watter faktore bydrae tot vinniger resolusie van Mycobacteria in sputum. Resultate verkry het aangedui dat die aard van die siekte tydens diagnose voorspelbaar was van die oorgangstye van beide smeer en kultuur in die finale modelle. Die rookstatus van individue sowel as die VDR genotipes het onafhanklik bygedrae tot die oorgangstyd van die smeer, met ApaI ‘AA’ en TaqI ‘T’ bevattende genotipes wat ‘n vinniger reaksie op tuberkulose behandeling voorspel het. Ter opsomming, die tyd wat dit ‘n individu op DOTS terapie neem om na sputum negatief oor te gaan kan onafhanklik deur die VDR genotipe voorspel word. Dit kan moontlik implikasies hê vir ander immunomodulerende terapië in die toekoms. Die identifisering van faktore wat bydra tot die vatbaarheid van turberkulose sal ons in staat stel om ‘n beter begrip te hê van die immuunrespons teen tuberkulose wat moontlik kan lei tot die ontwikkeling van akkurate behandelings en inentings.
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Tzafettas, Marilena. "Women's decision making process regarding prenatal diagnostic testing." Thesis, London Metropolitan University, 2017. http://repository.londonmet.ac.uk/1244/.
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Objective: Expanding the original scope of the study, which was to explore the decision-making process of pregnant women in the uptake of invasive diagnostic tests - amniocentesis and Chorionic Villus Sampling (CVS) – and taking into account the latest emergence of a Noninvasive Prenatal Testing, NIPT, the primary goal of this study was to explore factors that influence women’s decision to have an invasive, a non-invasive or no further testing at all. Design and sample: The Prenatal Decision Making Questionnaire (PDMQ) developed for the purposes of this study. Following a pilot test and factor analysis, it was distributed to a population of pregnant women (N=421) prior to them receiving their combined screening results. The total sample was divided into three sub-groups according to their risk status (low-intermediate-high) for the analysis. Results. Logistic regression analysis using the R version 3.0.3 revealed that none of the PDMQ factors had a significant impact on women’s decision to have an invasive test (CVS), whereas the following three factors had a significant impact on the decision to have a non-invasive test (NIPT): negative attitude to doctors and an internal locus of control were associated with the uptake of NIPT, whereas a negative attitude to medicine was associated with rejection of NIPT When risk status was included in the model it was found that uptake of NIPT was predicted by the presence of some level of risk for T21 or T13/T18. On the contrary, uptake of CVS was only predicted by an increased risk for T21. Conclusion(s): Women’s decision making process in prenatal diagnosis is affected by several factors with personalised risk being one of the key determinants. The findings of this study can be used by healthcare professionals in providing the appropriate support and information and facilitating an informed decision during this stage of pregnancy.
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Chassin, Ludovic Jean. "In silico testing of glucose controllers : methodology and sample application." Thesis, City University London, 2005. http://openaccess.city.ac.uk/8435/.
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Diabetes mellitus designates a range of metabolic disorders characterised by hyperglycaemia due to deficient or absent insulin secretion, insulin action, or both. In particular, Type 1 diabetes is characterised by a total lack of endogenous insulin secretion which has to be replaced by exogenous insulin to control the plasma glucose concentration. An extracorporeal wearable artificial pancreas (AP) has been a research aim for over three decades. The research is motivated by the need to improve glucose control. Results of a major study, the Diabetes Control and Complications Trial (DCCT), have demonstrated that improvements in glucose control prevent or delay long term complications, which are the main causes of morbidity and mortality in subjects with Type 1 diabetes. Prior to a clinical evaluation, performance of new medical devices can be tested in silico. Such an approach has been adopted extensively by the pharmaceutical industry in the development of new drugs. In silica testing benefits from relatively low financial, human, and time costs by comparison with the resources required for a full clinical evaluation. The aims of the present thesis are to identify components of the AP, integrate them into a simulation environment, and design an in silico evaluation strategy for the development of closed-loop algorithms with the ultimate goal to assess safety and efficacy prior to clinical evaluation. In the present work, submodels of metabolic processes were linked to represent the characteristics of the glucoregulation in Type 1 diabetes. The submodels were associated with sets of parameters to account for variability in population and individual responses to meals and insulin therapy. The model of glucoregulation in Type 1 diabetes was extended by models of subcutaneous (sc) glucose sensing and sc insulin delivery to represent all aspects of the AP. A systematic approach was developed and employed to evaluate, in silica, the potential and limitations of an AP glucose controller. This was exemplified by evaluating a nonlinear model predictive controller. The robustness of the AP was explored by hypothesising various perturbations induced by different system components. A further objective included the establishment of a qualitative grading scheme of glucose control from the clinical viewpoint. This was followed by a comparison between results from simulations and a clinical trial of 24 hours, which gave the proof of concept of in silica testing. It was found that despite discrepancies due to initial conditions and meal differences, the simulations indicated well the outcome of the clinical trial. In conclusion, the thesis demonstrates the significant potential of in silica testing to make predictions about system behaviour aiding the assessment of safety and efficacy of control algorithms during the development of an AP.
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Suchinda, Chatr. "Experimental and analytical investigation of the thermal behavior of a fiber reinforced polymeric bridge deck." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19250.
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Nelson, Burke I. "An improved in-line process rheometer for use as a process control sensor /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64059.
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Thompson, Danny C. "Structure-property relationships of electron beam cured systems containing bis-GMA." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/94482.
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Structure-property relationships were investigated for the bis-glycidyl methacrylate deriva-tives of bisphenol-A crosslinked by electron beam irradiation. This material, commonly called bis-GMA, is a viscous liquid at room temperature which crosslinks to form a glassy network when a 3 to 5 mil coating is irradiated with sufficient energy. The major parameters which were systematically varied in this study were radiation dosage, dose rate, aging time after irradiation, and post-cure annealing at higher temperatures.
Measurements were conducted first to quantify the crosslinking reaction, then to characterize the physical properties of the resulting networks. Extraction by a solvent was done to deter-mine the degree of network formation through the equilibrium swelling ratio and the gel weight fraction after drying. Another method utilized FTIR to monitor the disappearance of double bonds as the crosslinking reaction proceeded. In order to characterize the physical properties, differential scanning calorimetry (DSC) and dynamic mechanical spectroscopy were done to determine the glass transition temperature.
It was found that the network density or amount of cure is proportional to the irradiation dosage, with an upper limit reached above some critical dosage. Dose rate was not found to influence the degree of cure greatly. The crosslinking reaction often became diffusion limited as vitrification occurred. These phenomena were discussed in terms of the well-known Time-Temperature-Transformation diagram. Free radicals trapped in these networks exhibited a finite lifetime. Post-curing can be achieved by annealing at a temperature above the T₉ of the network, as shown by the increase of the glass transition temperature from DSC and dynamic mechanical results.
Bis-GMA was mixed with rubbery modifier materials with acrylate and methacrylate functional ends in order to toughen the bis-GMA networks. It was observed that the acrylate end groups were more reactive in EB cured systems than analogous methacrylates probably due to their higher polymerization enthalpy and less steric hindrance. Phase separation, which would provide rubber toughening without depressing the high glass transition temperature, was not achieved by irradiation with the modifying materials at the molecular weights used in this study, but the mixtures were toughened as shown by the dynamic mechanical data.M.S.
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Chen, Zhaoyu [Verfasser], and Stefan [Akademischer Betreuer] Diebels. "Nanoindentation testing of soft polymers : computation, experiments and parameters identification / Zhaoyu Chen. Betreuer: Stefan Diebels." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1053985304/34.
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Walker, Andrew. "Performance testing of ultrasound Doppler equipment." Licentiate thesis, Linköping University, Linköping University, The Institute of Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-29499.
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Blood and tissue velocities are measured and analysed in cardiac, vascular and other applications of diagnostic ultrasound. Errors in system performance might give invalid measurements.
We developed two moving string test targets (“Doppler phantoms”) to characterise ultrasound Doppler systems. These phantoms were initially used to measure such variables as sample volume dimensions, location of the sample volume, and the performance of the spectral analysis. Specific tests were done to detect errors in signal processing causing time delays and inaccurate velocity estimation.
Even time delays as short as 30 ms in cardiac motion pattern may have clinical relevance. These delays can be measured with echocardiography, by using techniques such as flow and tissue Doppler and M-mode together with external signals (e.g., ECG and phonocardiography). If one or more of these signals are delayed in relation to the other signals (asynchronous), an incorrect definition of cardiac time intervals can occur. To determine if this time delay in signal processing is a problem, we tested three commercial ultrasound systems. We used a digital ECG simulator and a Doppler string phantom to obtain test signals. We found time delays of up to 90 ms in one system, whereas delays were mostly short in the other two systems. Further, the time delays varied relative to system settings.
To determine the accuracy in velocity calibration, we tested the same three ultrasound systems using the Doppler phantom to obtain test signals for flow and tissue pulsed Doppler and for continuous wave Doppler. The ultrasound systems were tested with settings and transducers commonly used in cardiac applications. In two systems the observed errors were mostly close to zero, whereas one system systematically overestimated velocity by an average of 4.6%. The detected errors can be considered small in clinical applications but might be serious in certain research applications. It is important to know the velocity error of the used ultrasound system and to judge it in relation to the application in which it is used.
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Gao, Yaohua. "Electrospinning of Resorbable Amino-Acid Based Poly(ester urea)s for Regenerative Medicine." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460374617.
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Almughem, Fahad. "Investigating novel cationic polymers for siRNA delivery for treatment of allergic disease." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/52376/.
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Spleen tyrosine kinase (Syk) is an enzyme which plays a prominent role in IgE-dependent signal transduction in type 1 hypersensitivity reactions. Due to the important role of Syk in the early signalling cascade in mast cells and basophils for inducing allergic reaction, it could be a suitable target for the treatment of allergy. In this project, the efficacy of Syk gene silencing in the inhibition of mast cell degranulation and cytokine induction by small interfering RNA (siRNA) in vitro was evaluated. The evaluation of the inhibition of Syk function was assessed by two novel rat basophil leukaemia (RBL-2H3) derived reporter cell lines which are Neuropeptide Y-Red Fluorescent Protein fusion (NPY–mRFP) and Nuclear factor of activated T-cells-DsRed (NFAT-DsRed) reporter cell lines. In NPY–mRFP reporter cells, red fluorescent protein (RFP) is targeted and stored in the granules and released into the medium during degranulation upon appropriate IgE-dependent stimulation of the cells. In NFAT-DsRed reporter cell, DsRed can be expressed upon appropriate IgE-dependent stimulation of the cells resulting in translocation of NFAT from the cytosol to the nucleus and reporter gene expression. Novel cationic polymers in this project were evaluated for the delivery of siRNA. The first polymer was AGMA29, an amphoteric linear polyamidoamine polymer which has been reported to be useful for gene delivery and with a low toxicity. In addition, two modified poly(glycerol adipate) (PGA) variants were used. PGA is a polyester which can be derivatised with a variety of substituents to make cationic polymers. Derived polymers PGA-50% lysine (PGA-50% Lys) and PGA-20% histidine (PGA-20% His) were evaluated in this work to determine the size, efficacy and toxicity of polyplexes used in the Syk siRNA delivery. Using optimised polyplex resulted in the knockdown of the Syk function in the release of RFP in NPY–mRFP and the DsRed induction in NFAT-DsRed reporter cell lines, optimal calcium concentration and media used were determined. A new method was established for measuring the release of RFP in the NPY–mRFP cells, which could be used for detecting allergic reactions. The results showed that the polyplexes could be used for transfection when they were prepared in deionised water. 5 RU/Nt of AGMA29/Syk siRNA H polyplex resulted in a 31% decrease in the release of RFP in NPY-mRFP cell lines in comparison to untreated cell or scrambled siRNA. PGA-50% Lys/Syk siRNA H at 10AA/Nt ratio resulted in a 31% decrease in the release of RFP in NPY-mRFP cell lines in comparison to untreated cell and 24% in comparison to scrambled siRNA. The final finding from evaluation of Syk mRNA by RT-qPCR showed that the Syk mRNA knockdown at 5 RU/Nt of AGMA29/siRNA H was low (~26%) after 48 hr of the transfection. Interestingly, almost complete knockdown of Syk mRNA by PGA-50% Lys/Syk siRNA H was achieved at 5,10, and 20 AA/Nt ratios. This work therefore contributes to the exploration of a novel polyester based polymer for siRNA gene therapy and compares it with a polyamidoamine based polymer. From the results obtained it is concluded that the novel polyester based polymer for siRNA delivery is safe, effective in the transfection of hard to transfect cells and could be used for future siRNA in vivo gene silencing applications.
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Haria, Mehul. "Design, synthesis, and optical characterization of a novel, biocompatible azo-polymer." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101850.
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The goal of this thesis was to create a novel stable water-soluble azo polymer with photoswitchable properties, which was to be used as a scaffold in directing neuron growth. The new polymer, PDR2, was synthesized and extensively characterized to understand its physical and chemical properties, as well as to ascertain the structure. Characterization techniques included nuclear magnetic resonance, thermogravimetric analysis, differential scanning calorimetry, absorption spectroscopy, and ellipsometry. The photoresponsive properties of the polymer were then studied by examining quantum yields and birefringence, and the variation of these properties with humidity was examined, after being deposited onto thin films using layer-by-layer self-assembly. Quantum yields were found to increase with humidity up to a maximum determined to be at approximately 30% relative humidity, and were then found to decrease with increasing humidity. This was thought to be due to a combination of factors including plasticization and the formation of water clusters. Birefringence experiments revealed that the thin films did not produce a stable birefringence state. Many factors, including low azo content in the polymer, interaction with polymer side groups, and the mobility of polyelectrolyte multilayers were thought to contribute to these results.
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Smith, Raphael V. "The design, construction and testing of a hermetically sealed breast platfrom for dual-modality mammography." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/6011.
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Includes abstract.Includes bibliographical references.
When ultrasound is used as an adjunct to X-ray mammography in either hand-held or automated mode, the patient typically lies in a prone position. The disadvantages of this approach include: variable image quality; poor co-registration of X-ray and ultrasound images; and increased costs and patient anxiety. In response to these shortcomings, the Aceso full-field digital mammography and automated breast ultrasound (FFDM+ABUS) system aims to acquire both X-ray and 3D ultrasound images simultaneously. The Aceso has been developed by the Cape Town based company CapeRay Medical (Pty) Ltd. The focus of this thesis is the design, construction and testing of a novel breast platform wherein the challenges of combining FFDM and ABUS have been addressed, in a clinically suitable package.
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Griffith, Bridget Catherine Hamilton. "Development and usability testing of a data visualisation platform for an African trauma data registry." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29873.
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Introduction Trauma is a significant contribution to the global burden of mortality and disease, especially in sub-Saharan Africa. The methods for tracking, recording, and analysing the incidence and causes of trauma are underdeveloped. To address this, The African Federation for Emergency Medicine (AFEM) developed a trauma form and Trauma Data Registry to collect trauma data in multiple sites in sub-Saharan Africa. We undertook a study to create, and assess the usability and functionality of, a trauma data visualisation platform for use in conjunction with the Trauma Data Registry. Methods We created a web-based trauma data visualisation platform for use with the AFEM Trauma Data Registry. This study involves a usability assessment of the AFEM Trauma Data Visualisation Platform to determine the specific website features and analytical needs of African trauma research facilities. This was done by surveying individuals from healthcare facilities that are currently using the AFEM Trauma Form. Two types of questionnaires were administered: Questionnaire I gathered information on the study population and their expectations for the platform, and Questionnaire II assessed the usability of the platform after it was introduced. Surveys took place in person and online, with the last group of questionnaires being administered on-site at the healthcare facility. Data were captured via Survey Monkey online and paper survey. The results were entered into Excel and analysed using descriptive statistics using Stata Version 14. Results A total of 45 healthcare practitioners from eight countries participated in the background survey. The greatest proportion were trained in Tanzania (14, 31.1%) and Ethiopia (14, 31.1%). The mean age of participants was 32.6 (SD=6.6). The mean number of years reported for working at their current facility is 3.7 (SD=3.5). The greatest number of participants in the survey were physicians (22, 48.9%) and specialists (11, 24.4%). Over half (53.3%, n=24) selected that they had moderate experience with data analysis, and the majority reported that they had less than three publications. A total of 34 HCPs participated in the usability study. The mean scores for the usability questionnaire portion were high, with all of the scores being above 6. Major positive themes of the participant comments included easy to use and time saving, major negative themes included feasibility concerns, and comments specific variable to add were common. Discussion There is a lot of heterogeneity in the data analysis and technology experience of participants. The participants were overall satisfied with the Trauma Data Platform. Participants’ comments and suggestions on elements to add indicate that there is still work to be done to design a Trauma Data Platform that is suitable for this setting. Conclusions Overall satisfaction with the Trauma Data Platform was high, and the user comments and suggestions will be incorporated into future versions of the platform. This research highlights the importance of considering the feasibility of health technology in its introduction.
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Krynauw, Hugo. "Design and implementation of an apparatus for hydrodynamic and fatigue testing of prosthetic aortic valves." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/3258.
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Includes abstract.Includes bibliographical references.
Aortic valve replacement in humans may be needed due to pathology leading to valve stenosis and regurgitation. Replacement is by either mechanical or soft tissue prosthetic valves. Before new valves are medically approved and introduced into the market they are required to undergo rigorous testing to verify performance and product life expectancy. Performance testing is done in a hydrodynamic test apparatus and life expectancy verified in an accelerated test apparatus. The Cardiology Department at Tygerberg Hospital has proposed a project for the design and implementation of a prosthetic aortic valve test apparatus. This device is to be used primarily for fatigue, but also limited hydrodynamic, testing of prosthetic heart valves. The design of the test apparatus was based on the four-element Windkessel model of the arterial system. This simple lumped parameter electrical analogy of the arterial system takes aortic and arterial resistance, arterial compliance, and blood inertance into account to simulate total arterial impedance. This model was developed with physiological reference and thus the element parameters only hold for physiological simulation as the equation governing impedance is speed sensitive. The model was adapted to provide theoretidal, physiological loads from physiological speeds of 60BPM through to accelerated speeds up to 1OOOBPM through mathematical optimisation of the Windkessel.The test apparatus was designed and built taking into account the varying Windkessel parameters where possible. Both compliance and resistance could be varied within an acceptable range, inertance however, could not be varied due to the limitations of the project. The apparatus was controlled and pressures on either side of the valve monitored with a LabView® graphical user interface. The apparatus was able to mimic in vivo closely and satisfied the ISO requirements for valve testing up to speeds of 230BPM. Various modifications are proposed to both the Windkessel model and the physical apparatus to compensate for hydrodynamic effects at high testing speeds in improve performance, as well as increase the maximum testing speed.
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Eng, Wilson S. "Nonlinear Stiffness and Viscoelasticity of Inhibitor-Treated Blood Clots by Tensile Testing." Thesis, San Jose State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13426960.
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Although blood clots are vital to wound healing, little is known about what factors influence clot stiffness and dynamic response. This work investigates the mechanics of inhibitor-treated clots by direct tensile testing using a custom designed system for forces below 1 N. Inhibitors that affect clot formation include blebbistatin, which affects myosin II movement on actin, and cytochalasin D, which affects actin polymerization. The hypothesis of this investigation is that blebbistatin will have a greater effect on mechanical behavior than cytochalasin D, because the inhibition of myosin II will weaken the overall clot more than actin. This hypothesis was investigated using clots that were treated with blebbistatin and cytochalasin, using untreated whole blood as a reference. Clots were tested from five different donors with at least two replicates from each donor. Each clot was subjected to an initial stretch ratio of 1.5 to measure nonlinear stiffness, followed by a series of 1 mm increments to record stress relaxation. At a stretch ratio of 1.5, blebbistatin-treated clots exhibited 4.3% lower tensile stress than cytochalasin-treated clots. The relaxation time constant for blebbistatin-treated clots was 10% faster than for cytochalasin-treated clots. This evidence supports the hypothesis about the role of myosin II in blood and introduces experimental methodology that can be extended to studies on mechanics of other soft biological tissues.
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Van, Zyl A. J. P. (Andries Jakobus Petrus). "Synthesis, characterization and testing of nano-structured particles for effective impact modification of glassy amorphous polymers." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53609.
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Thesis (PhD)--Stellenbosch University, 2003.ENGLISH ABSTRACT: The synthesis of structured nanoparticles, in particular core/shells, IS of great technological and economical importance to modem materials science. One of the advantages of structured particles is that they can be synthesized with either a solid core (albeit soft or hard) or a liquid core (of varying viscosity). This adds to the versatility of structured particles and their relevance to a majority of industrial and commercial endapplications. The synthesis of core/shell particles with liquid cores was investigated for the effective impact modification of glassy amorphous polymers. Polybutyl acrylate was chosen as the shell due to its rubbery nature. Hexadecane functioned as the core oil and facilitated osmotic stability by being a suitable hydrophobe for the miniemulsion synthesis. Polymer synthesis was preceded by the prediction of particle morphology by using thermodynamic prediction models. Core/shell particles with liquid cores were synthesized via miniemulsion polymerization. This resulted in the direct introduction of core-oil and monomer into the miniemulsion droplets. Polymerization was achieved in situ, resulting in the formation of particles with the desired morphology. For additional strength, stability and matrix mixing capabilities, methyl methacrylate (MMA) was grafted onto the initial core/shell particles. The obtained morphology was in contradiction with the predicted morphology, thus pointing to strong kinetic influences during the polymerization process. These influences could be attributed to surface anchoring of polymer chains due to the initiator (KPS) used, the establishment of the polymerization locus as well as the increase in viscosity at the polymerization locus. To test these influences a surface-inactive initiating species (AIBN) and an interfacial redox initiating species (cumyl hydroperoxide/Fe/") were used. Use of the former resulted in the formation of solid polymer particles due to homogeneous polymerization throughout the droplet, thus leading to an inverse core/shell morphology as a result of thermodynamic considerations. The redox initiator promoted kinetic influences as a result of fast polymerization kinetics at the droplet/water interface. This, as well as the increase in viscosity, facilitated the production of core/shell particles. To obtain core/shell particles with the desired size, the influence of surfactant concentration was investigated. Capillary hydrodynamic fractionation (CHDF) was used to determine the particle size of the initial core/shell particles as well as the size of the MMA-grafted core/shell particles. The area stabilized per surfactant molecule was calculated stoichiometrically and compared to "classical" miniemulsion results, i.e. data generated from the synthesis of polymeric latexes in the presence of a hydrophobe, but at a much lower hydrophobe:monomer ratio than was used here. The influence of methanol as well as the possibility of scaling-up the process was also investigated. The study was further expanded to the investigation of living miniemulsion polymerization techniques to control the molecular architecture of synthesized core/shell latexes. The influence of different RAFT agents, initiators and monomers were investigated on the core/shell formation properties of the investigated systems. The combined effects of establishing the polymerization locus as well as increased polymerization kinetics, thus increasing the viscosity at the polymerization locus, lead to the successful formation of liquid- filled core/shell particles. To conclude, the ability of the synthesized core/shell particles to induce impact modification in glassy amorphous polymers was investigated. Results showed that incorporation of these particles could effectively modify the intrinsic properties of the investigated polymers, resulting in a brittle-to-ductile transition. Improved impact results of the investigated glassy matrix were obtained. Keywords: core/shell, liquid-filled, RAFT, miniemulsion, impact modification
AFRIKAANSE OPSOMMING: Die sintese van gestruktureerde nano-partikels, meer spesifiek kern/skil partikels, is van onskatbare tegnologiese en ekonomiese belang vir moderne materiaalkunde. Een van die voordele van hierdie tipe partikels is dat sintese kan geskied met 'n soliede kern (hard of sag) of vloeistofkern (met wisselende viskositeit). Dit dra by tot die veelsydigheid van gestruktureerde partikels en dus tot grootskaalse aanwending in industriële en kommersiële toepassings. Die sintese van kern/skiI partikels met vloeistofkerne is ondersoek met die oog op effektiewe slagsterkte modifikasie van glasagtige amorfe polimere. Polibutielakrilaat is gekies as skil-polimeer op grond van sy rubberige voorkoms. Heksadekaan moes funksioneer as die kern-olie, maar het ook bykomende osmotiese stabiliteit verleen tydens die miniemulsie-polimerisasie proses. Dit is as gevolg van die gepaste hidrofobiese eienskappe van heksadekaan. Polimeer sintese is voorafgegaan deur die voorspelling van partikel morfologie met behulp van termodinamies gebaseerde voorspellingsmodelle. Kern/skil partikels is gesintetiseer deur middel van 'n miniemulsie-polimerisasie reaksie wat die direkte inkorporering van kern-olie en monomeer in die miniemulsiedruppel teweeg bring. Polimerisasie vind in situ (lat. vir in die oorspronklike plek, m.a.w. binne-in die druppel) plaas en lei tot die vorming van partikels met die gewenste morfologie. Metielmetakrilaat is ge-ent op die oorspronklike kern/skil partikels om addisionele sterkte, stabiliteit en vermenging met die matriks polimeer te bewerkstellig. Die verkrygde morfologie is teenstrydig met die voorspelde morfologie, wat dus die teenwoordigheid van sterk kinetiese invloede aandui. Hierdie invloede kan toegeskryf word aan die oppervlak-aktiewe afsetter (KPS, kaliumpersulfaat) wat gebruik is, die daarstelling van die polimerisasie lokus asook die toename in viskositeit by die lokus van polimerisasie. Om hierdie invloede te toets is 'n oppervlak-onaktiewe afsetter (AIBN, asobisisobutironitriel) en intervlak redoks-afsetter (kumielhidroperoksied/Pe'") gebruik. Gebruik van eersgenoemde het die vorming van soliede partikels teweeg gebring. Dit is as gevolg van homogene polimerisasie in die druppel en dus die ontstaan van omgekeerde kern/skiI partikels weens termodinamiese oorwegings. Die redoks-afsetter het egter die kinetiese oorwegings bevoordeel as gevolg van vinnige polimerisasiekinetika by die druppel/water intervlak. Dit, tesame met die toename in viskositeit, maak die produksie van kern/skil partikels moontlik. Vir die verkryging van kern/skiI partikels met die gewenste partikelgrootte is die invloed van die seep konsentrasie ondersoek. CHDF (eng. capillary hydrodynamic fractionation) is gebruik om die partikelgrootte van die oorspronklike kern/skiI partikels, sowel as dié ge-ent met metielmetakrilaat, te bepaal. Die area gestabiliseer per seepmolekule is bereken d.m.v. stoichiometrie en vergelyk met "klassieke" miniemuisie data, d.i. data verkry deur die sintese van latekse in die teenwoordigheid van 'n hidrofoob, maar teen 'n baie laer hidrofoob:monomeer-verhouding as wat hier gebruik is. Die invloed van metanol, asook die moontlikheid om die reaksie op te skaal, is ondersoek. Die studie is verder uitgebrei om die invloed van lewende miniemulsie-polimerisasie tegnieke in te sluit, om sodoende beheer uit te oefen oor die molekulêre argitektuur van die gesintetiseerde latekse. Die invloed van verskeie RAFT (eng. reversible additionfragmentation chain transfer) agente, afsetters en monomere op die kern/skiI vormingsmoontlikhede van die bestudeerde stelsels, is ondersoek. Die gesamentlike effek van die daarstelling van die polimerisasie lokus en dus die verhoging van die viskositeit by die lokus, lei tot die suksesvolle vorming van vloeistof-gevulde kern/skiI partikels. Laastens is die invloed van die gesintetiseerde kern/skil partikels op die slagsterkte van glasagtige amorfe polimere ondersoek. Resultate dui daarop dat die insluiting van hierdie partikels kan lei tot die effektiewe verandering van die intrinsieke eienskappe van die bestudeerde polimere, en dus 'n oorgang van bros na rekbaar kan veroorsaak. 'n Verbetering in die slagsterkte resultate van die bestudeerde glasagtigte matriks is ook waargeneem.
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FARINA, LUIS C. "Caracterizacao viscoelastica por meio de ensaios de fluencia e ruptura por fluencia de compositos polimericos de matriz de resina epoxidica e fibra de carbono." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9391.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Wand, Benedict Martin. "Developing, testing and refining a physiotherapy model of care for acute low back pain." Thesis, Brunel University, 2002. http://bura.brunel.ac.uk/handle/2438/7124.
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This thesis is concerned with the physiotherapy management of acute low back pain. Various national guidelines contain conflicting views regarding the role of physiotherapy in the management of acute low back pain. The discrepancies involve primarily the content and timing of physiotherapy intervention. There is a need to place the physiotherapy management of acute low back pain on a more firm research base. A comprehensive literature review was undertaken to develop a best practice model of care for acute low back pain. This model was tested in a randomised controlled trial. Subjects involved in the treatment model demonstrated significantly better short-term outcomes than subjects given advice only. Furthermore, subjects treated early demonstrated significantly better long-term outcome than subjects who waited six weeks for their treatment. Changes in pain and physical function were found to be the factors most closely associated with good outcome in the short-term. Good outcome in the long term was associated with improvement in a number of physical and psychological variables. It is recommended that changes be made to the treatment model to facilitate improvement in pain relief and maintenance of physical and social function to further enhance treatment effectiveness.