Дисертації: "Diffusion mechanism of degradation"

1

Lowe, Michael John Stuart. "Plate waves for the NDT of diffusion bonded titanium." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8011.

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2

Shushan, S. M. "The susceptibility of diffusion bonded joints to stress corrosion cracking." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295046.

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3

Williams, Pascal I. "A study of corrosion and chromium diffusion for power station boiler tube materials." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/26899.

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4

Patel, Prakash Shashikant. "Diffusion problems and degradation of bearing overlays." Thesis, London Metropolitan University, 1989. http://repository.londonmet.ac.uk/3192/.

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The corrosion and degradation of Pb-Sn bearing overlays Is a bilateral process . During service, the lubricant becomes corrosive due to the breakdown of inhibitors with subsequent oxidation occurring at operating temperatures (120-170[degrees]). ...

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5

Morton, Nicholas Ryan. "Quenching Limits and Materials Degradation of Hydrogen Diffusion Flames." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8161.

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Thesis (M.S.) -- University of Maryland, College Park, 2008.
Thesis research directed by: Dept of Fire Protection Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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6

Boudghene, Stambouli Amine. "Degradation mechanism in zinc sulphide/manganese electroluminescent displays." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328389.

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7

Lorite, M. J. "Mechanism of muscle protein degradation in Cancer Cachexia." Thesis, Aston University, 1997. http://publications.aston.ac.uk/15707/.

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A protein-mobilising factor of estimated molecular weight 24 KDa (p24) was purified both from the cachexia-inducing MAC 16 tumour and the urine of cachectic cancer patients by a combination of ammonium sulphate precipitation and affinity chromatography using a monoclonal antibody developed against the murine material. Administration of p24 to non tumour-bearing mice caused a decrease in body weight 24 h after the first injection, which was attenuated by prior treatment with the monoclonal antibody. Loss of body weight was accompanied by an accelerated loss of skeletal muscle protein, as determined by the release of tyrosine from this tissue. This was associated with an increased release of PGE2 and both protein degradation and PGE2 release were attenuated by the monoclonal antibody. Loss of protein mass arose from both a decrease in the rate of protein synthesis and an elevation of protein breakdown; the latter due to an activation of the ubiquitin-proteasome proteolytic system. In isolated muscle, p24 was capable of promoting protein breakdown and this was also associated with increased PGE2 levels. Both tyrosine and PGE2 release, were inhibited by PGE2 inhibitors and a specific inhibitor of cPLA2. When added to muscle cells in culture, p24 caused an elevation in the rates of total and myofibrillar protein breakdown and a depression in the rate of protein synthesis which was inhabitable by short-term incubation in insulin, suggesting that p24 may inhibit protein synthesis by causing an arrest in the translational process.

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8

Yoshida, Masayuki, Masami Morooka, Shuji Tanaka, and Manabu Takahashi. "Formation mechanism of plateau, rapid fall and tail in phosphorus diffusion profile in silicon based on the pair diffusion models of vacancy mechanism and interstitial mechanism." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196177.

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9

Harrington, Tomas Seosamh. "Gas diffusion electrodes for environmental applications." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297872.

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10

Xiao, Jirong. "The diffusion mechanism of hydrocarbons in zeolites." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/33810.

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11

Li, Juchuan. "UNDERSTANDING DEGRADATION AND LITHIUM DIFFUSION IN LITHIUM ION BATTERY ELECTRODES." UKnowledge, 2012. http://uknowledge.uky.edu/cme_etds/12.

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Lithium-ion batteries with higher capacity and longer cycle life than that available today are required as secondary energy sources for a wide range of emerging applications. In particular, the cycling performance of several candidate materials for lithium-ion battery electrodes is insufficient because of the fast capacity fading and short cycle life, which is mainly a result of mechanical degradation. This dissertation mainly focuses on the issue of mechanical degradation in advanced lithium-ion battery electrodes. Thin films of tin electrodes were studied where we observed whisker growth as a result of electrochemical cycling. These whiskers bring safety concerns because they may penetrate through the separator, and cause short-circuit of the electrochemical cells. Cracking patterns generated in amorphous silicon thin film electrodes because of electrochemical cycling were observed and analyzed. A two-dimensional spring-block model was proposed to successfully simulate the observed cracking patterns. With semi-quantitative study of the cracking pattern features, two strategies to void cracking in thin-film electrodes were proposed, namely reducing the film thickness and patterning the thin-film electrodes. We also investigated electrodes consisting of low melting point elements and showed that cracks can be self-healed by the solid-to-liquid phase transformation upon cycling. Using gallium as an example, mechanical degradation as a failure mechanism for lithium-ion battery electrodes can be eliminated. In order to quantitatively understand the effect of surface modification on electrodes, we analyzed diffusion equations with boundary conditions of finite interfacial reactions, and proposed a modified potentialstatic intermittent titration technique (PITT) as an electro-analytical technique to study diffusion and interfacial kinetics. The modified PITT has been extended to thin-film geometry and spherical geometry, and thus can be used to study thin-film and composite electrodes consisting of particles as active materials.

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12

Xin, Yunchang. "Degradation mechanism and surface modification of biomedical magnesium alloy /." access full-text access abstract and table of contents, 2010. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ap-b30011723f.pdf.

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Thesis (Ph.D.)--City University of Hong Kong, 2010.
"Submitted to Department of Physics and Materials Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references.

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13

Bi, Wu. "PEM fuel cell catalyst degradation mechanism and mathematical modeling." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29756.

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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Fuller, Thomas; Committee Co-Chair: Deng, Yulin; Committee Member: Gallivan, Martha; Committee Member: Kohl, Paul; Committee Member: Singh, Preet. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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14

Hands, Katherine J. "Defining the mechanism of arsenic-induced degradation of PML." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/a5b14b03-25b0-457f-8dd9-9facf98b6415.

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Arsenic trioxide is a clinically effective treatment for the disease acute promyelocytic leukaemia (APL) which is caused by the chromosomal translocation t(15;17) which fuses the promyelocytic leukaemia (PML) protein to the retinoic receptor alpha (RARa). The PML-RARa oncoprotein disrupts normal retinoic acid signalling and the function of PML nuclear bodies (PML-NBs), subnuclear protein complexes with roles in control of apoptosis and cellular senescence. Treatment with arsenic induces rapid post translational modification of PML and with the small ubiquitin like modifier (SUMO). SUMO modification of PML recruits the SUMO targeted ubiquitin E3 ligase RNF4 via four SUMO interaction motifs within the N-terminal region of RNF4. PML is then ubiquitylated and targeted for proteasomal degradation. In APL, these events trigger degradation of PML-RARa, curing the disease. To further investigate the process of arsenic induced degradation of PML, a high content siRNA screen was designed to monitor the fate of a YFP linked version of PML after siRNA mediated knockdown of components of the ubiquitin system and arsenic treatment. RNF4 depletion prior to arsenic treatment prevented PML degradation and resulted in accumulation of PML in large, bright PML-NBs. This was used as a positive control. A library of siRNAs targeting 1067 gene products were screened to identify those which perturbed the process of arsenic mediated degradation of PML, and those which affected the stability of PML in untreated cells. A number of putative hits were identified. Depletion of the cullin RING ligase scaffold CUL3, and the NEDD8 E3 ligase DCUN1D1 resulted in striking accumulation of PML, suggesting PML may be a substrate of a CUL3 RING ligase complex. Further experiments using the inhibitor of neddylation, MLN4924 support this hypothesis. PML is expressed as a various isoforms which encode a unique C-terminal region, due to alternative splicing. The second part of this study investigated the role of this variable C-terminal region in the response of the six major PML isoforms to arsenic treatment. Using a system in which only a single eYFP-linked PML isoform is expressed, differences in the localisation of PML isoforms following arsenic treatment were identified, with PML I, II and VI found to accumulate in the cytoplasm following arsenic treatment, whereas PML III, IV and V did not. A high content imaging assay identified PML V as the isoform most readily degraded following arsenic treatment, and PML IV as relatively resistant to degradation. Using siRNA it was demonstrated that arsenic induced degradation of all PML isoforms is dependent on the ubiquitin E3 ligase RNF4. Intriguingly, depletion of RNF4 resulted in marked accumulation of PML V, suggesting this isoform is an optimal substrate for RNF4. Thus the variable C-terminal domain influences the rate and location of degradation of PML isoforms following arsenic treatment.

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15

Yoshida, Masayuki, Masami Morooka, Shuji Tanaka, and Manabu Takahashi. "Formation mechanism of plateau, rapid fall and tail in phosphorus diffusion profile in silicon based on the pair diffusion models of vacancy mechanism and interstitial mechanism." Diffusion fundamentals 2 (2005) 62, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14396.

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16

Sugimoto, Hidehiko, and Yuh Fukai. "Migration mechanism in defect metal hydrides containing superabundant vacancies." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-191659.

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17

Lechner, Ruep Ekkehard, Goetz Schuck, and Klaus Langer. "Mechanism of proton conduction in solid-state protonic conductors." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-186538.

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18

Jain, Abhilash. "The mechanism of tendon degradation by tenosynovium in rheumatoid arthritis." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411665.

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19

Greenbank, William. "Interfacial stability and degradation in organic photovoltaic solar cells." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0338/document.

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Les durées de vie des cellules solaires photovoltaïques organiques (OPV) doivent être améliorées afin que cette technologie puisse être commercialisée sur une grande échelle. Ce travail étudie l’influence de la sélection des matériaux pour l’interface supérieure sur la dégradation des OPV inversées. La première partie de cette étude s’occupe des effets de la dégradation thermale. Il a été constaté que la tension de circuit-ouvert (VOC) et le facteur de forme (FF) diminuent lors du vieillissement des OPVs ayant une HTL de MoO3 et une électrode d’argent. Des expériences de caractérisation physique ont mis en évidence que les électrodes d’argent démouillent lors du vieillissement thermique ce qui peut conduire à la mort rapide des cellules avec des électrodes minces. Des analyses de rupture ont également faites. Il a été constaté que l’adhésion d’interface supérieure augmente fortement dans les échantillons avec électrode en argent due à la diffusion de matière, et il est possible qu’il y ait une relation entre cette diffusion et la perte de VOC et FF. Dans la deuxième partie, les effets de la lumière sur la dégradation et l’influence de la présence d’oxygène ou d’humidité ont été étudiés. Quelques effets des matériaux ont été notés, en particulier sur la durée de vie. L’oxygène a eu l’effet d’accélérer notablement la dégradation, et aucune différence n’a été notée selon les matériaux utilisés. En revanche, l’humidité a eu un effet prononcé sur les échantillons avec certains HTLs. Ce travail souligne l’importance de penser à la durée de vie quand on désigne les dispositifs OPV, en particulier pour sélectionner des matériaux appropriés afin d’optimiser la durée de vie
Organic photovoltaic (OPV) solar cells show great promise but suffer from short operating lifetimes. This study examines the role that the selection of materials for the hole extraction interface in inverted OPV devices plays in determining the lifetime of a device. In the first part of the study, the effects of thermal degradation were examined. It was found that devices containing MoO3 HTLs and silver top electrodes exhibit an open-circuit voltage (VOC)/fill factor (FF)-driven mechanism. Physical characterisation experiments showed that, with heating, the silver electrode undergoes de-wetting. With thin electrodes this can result in the catastrophic failure of the device. A fracture analysis study found that silver-containing devices experience an increase in adhesion of their top layers to the active layer due to interdiffusion between the layers. This interdiffusion may be related to the loss of VOC and FF in Ag/MoO3 devices through diffused species forming charge traps in the active layer. In the second part of the study, the effects of photodegradation in different atmospheres were studied. Some material-dependent effects were observed when the devices were aged in an inert atmosphere, including variations in projected lifetime. The effect of oxygen was to greatly accelerate degradation, and remove any of the material-dependence observed in the inert experiment, while humidity led to a substantial increase in the degradation rate of devices containing PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate). This study underlines the importance of considering device lifetime in device design, and choosing materials to minimise degradation

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20

Sammon, Christopher. "Vibrational spectroscopic studies of degradation and diffusion processes in poly(ethylene terephthalate)." Thesis, Sheffield Hallam University, 1997. http://shura.shu.ac.uk/3100/.

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The interaction of polyethylene terephthalate (PET) with water at both ambient and elevated temperatures has been studied. The diffusion of water, at ambient temperatures, into PET films, ofthe order of 10 um thick, has been followed using Founer transform infrared attenuated total reflectance, FT-IR ATR, spectroscopy. Films of differing degrees ofcrystallinity were prepared using two different methods. One method involved the annealing ofthe cast films at 85-90° C for different lengths oftime, to obtain a range of crystallinities. The other method involved the incorporation of different amounts ofan isophthalate group, to obtain a range of crystallinities. The rate of water diffusion with time was then measured as a function of crystallinity. The diffusion was shown to be classically Fickian in nature and the diffusion coefficients decreased with increased polymer crystallinity for both sets offilms. The perturbation of the v(OH) band of the water in the polymer matrix was studied as both a function oftime (i.e. concentration) and crystallinity. The water band was shown to be decoupled at low concentrations within the polymer matrix, indicating a breaking up of the water hydrogen bonding network. At higher concentrations, longer times, the v(OH) band gained more 'pure water' like character, but remained at higher frequency than pure water even at equilibrium water content, suggesting clustering of the water molecules, but an overall weakening ofthe hydrogen bonding network relative to the pure water spectrum. The study ofthe interactions ofwater at elevated temperatures including the degradative hydrolysis of PET at 90° C was undertaken using reflection absorption infrared spectroscopy (RAlRS). Films of <150 nm were immersed in pure water at 52,62, 70, 80 and 90° C and the effect on the polymeric structure was examined. At temperatures below 90° C the effects noted, on the time scales studied, were annealing effects, resulting in an increase in crystallinity. Estimations ofthe apparent activation energy ofthe gauche to trans isomerisation, for different degrees ofcrystallinity, were calculated and were found to be lower than those reported in the literature in air. This difference was thought to be a result ofthe plasticisation effects of water. At 90° C, during several days of immersion, the polymer was found to undergo hydrolysis. Complex changes in the RAIRS spectrum were related to changes in the polymeric structure, resulting from degradation. The autocatalytic nature ofthe degradation was highlighted, as was the loss of(small) mobile species from the polymer matrix. Amechanism involving the preferred site ofhydrolysis being a terminal ester group was proposed. Comparisons with hot alkaline hydrolysis were made. This occurred much faster and with more random chain scission. The diffusion of two organic liquids, methanol and ethylene glycol, into PET was studied. The diffusion was shown to be non-Fickian in nature due to the swelling and crystallisation that accompanied the diffusion. For the amorphous PET films, diffusion was accompanied by swelling and crystallisation for both molecules and was fitted to a dual sorption model. There was spectroscopic evidence for both a 'bound' alcohol- PET moiety and a 'free' alcohol species within the polymer matrix. For methanol in PET, the proportion of the sorbed alcohol which was 'bound' was found to increase with crystallinity, but for ethylene glycol the reverse was true. For methanol diffusion, increasing the crystallinity was shown to have a drastic effect on both the rate of diffusion and degree of swelling. For ethylene glycol diffusion, the degree of crystallinity appeared to affect the rate of swelling and the initial rate of sorption of penetrant, but the rate of the subsequent diffusion seemed to be unaffected by morphology. The interface between two layers of 20 and 30 um co-extruded PET laminates of PET and PET with an isophthalate comonomer, were examined using confocal Raman microscopy. The methods of confocal depth profiling through the polymer laminate and scanning, step-wise, along a cut edge were compared. The interface was examined using the carbonyl band width ofPET as an indicator of crystallinity. The interface was shown to be 2-3 um thick, independent of film thickness and contain a gradient of v(C=O) band width, indicating either interdiffusion or a transesterification reaction between the two polymer layers during co-extrusion.

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21

Lee, Chung-Ying Daniel. "The Mechanism of Apolipoprotein E in the Proteolytic Degradation of Aβ". Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1332820366.

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22

Vergadou, Niki, and Doros N. Theodorou. "Microscopic diffusion mechanism of CO 2 in a glassy amorphous polymer matrix." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188908.

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23

Soulas, Dimitrios N., and Kyriaki G. Papadokostaki. "Experimental investigation of the release mechanism of hydrophilic solutes from hydrophobic matrices." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188878.

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24

Yoshida, Masayuki, Hajime Kitagawa, Masami Morooka, and Shuji Tanaka. "Quantitative study of near equilibrium in dissociative mechanism of nickel in silicon." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192796.

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The dissociative mechanism of nickel in silicon has been studied experimentally, assuming the near equilibrium represented by CiCV / Cs = Ci eq C eq / Cs eq , where subscripts i, V, and s represent interstitial nickel atoms, vacancies, and substitutional nickel atoms, respectively, superscript eq represents the thermal equilibrium, and CA is the concentration of component A. However, the assumption of the near equilibrium has not yet been verified experimentally, because it is difficult to measure CV in silicon. In the present work, the simultaneous diffusion equations of the dissociative mechanism of nickel in silicon are solved numerically by double-precision FORTRAN without assuming the near equilibrium under the condition of in-diffusion of nickel into a silicon specimen, and the establishment of the near equilibrium is verified. It is also clarified that the near equilibrium is a transitional process which continues until the thermal equilibrium is reached. After the near equilibrium is reached, the very small difference of two nearly equal terms is an important factor in solving the diffusion equations. In other words, high accuracy is necessary to solve the diffusion equations. Concerning this, it is verified that the accuracy of double-precision FORTRAN is sufficiently high to solve the diffusion equations in the present work.

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25

Chen, Qu, Yingchun Liu, Qi Wang, and Keith E. Gubbins. "The role of hydrogen bond in mechanism of water diffusion in carbon nanotubes." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-185527.

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26

Sugimoto, Hidehiko, and Yuh Fukai. "Migration mechanism in defect metal hydrides containing superabundant vacancies." Diffusion fundamentals 11 (2009) 102, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A13024.

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27

Li, Xiao. "Short Circuit Capability and Degradation Mechanism Analysis of E-mode GaN HEMT." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492643687305536.

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28

Caicedo, Parra Dina Maria. "Mechanism to Quantify Road Surface Degradation and Its Impact on Rolling Resistance." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555430578466857.

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29

Jopling, Helen Mary. "A Mechanism for VEGFR2 Trafficking, Signalling and Degradation in Human Endothelial Cells." Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515561.

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30

Sabbir, Md Ahsan. "Corrosion Degradation Mechanism of CBPC Coating System for Highway Bridge Steel Components." FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3179.

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Coatings are widely used to mitigate corrosion of structural steel in aggressive humid environments. However, the service life is often diminished in aggressive environments. Repair of coatings can be costly due to materials, labor and environmental controls. So, in search for novel coatings, Chemically Bonded Phosphate Ceramic (CBPC) coating was investigated for marine bridge application. The research on CBPC coating considered various exposure environments such as inland, beach, salt-fog, wet and alternate wet and dry exposure to identify the degradation mechanism. To assess the corrosion damage, the coating was evaluated by visual inspection, thickness, adhesion, microscopy and X-ray diffraction. The CBPC coating degraded initially due to alternate wet and dry exposure. The unreacted coating constituent reacted further in moist environment to form magnesium phosphate hydrate and enhanced bulk coating porosity. That facilitated moisture to the coating substrate and formed apparent protective iron phosphate hydrate by interaction with steel substrate to the coating constituents. Passive-like conditions were observed in wet test of chloride-free solutions for the formation of hydration product of magnesium but that type of hydrate was not identified in chloride solution for the apparent high solubility. The resolved coating impedance parameters were introduced to characterize the bulk ceramic degradation. The solution resistance did show a decrease for all samples due to leaching of minerals from the bulk material. The resolved pore resistance did not show any distinct change, though there was an indication of bulk coating degradation by MIP. Water saturation level during exposure was also calculated from the resolved capacitance. An approach was proposed to transfer the pre-exponential term, Yo to coating capacitance, CC for ceramic coating. The estimated value of the coating capacitance from the developed technique indicated early saturation with water during exposure due to the porosity. So, the extent of CBPC coating permeability and degradation could not be resolved only by conventional analysis approaches. However, the formation of iron hydrogen phosphate hydrate and iron phosphate hydrate from reaction of unreacted coating constituents was thought to provide apparent enhanced corrosion protection but there is a probability of steel substrate corrosion in extended exposure in humid environment.

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31

Mkedder, Ilham. "Modification et dégradation enzymatique de polysaccharides : investigation par imagerie et diffusion de rayonnement." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00770180.

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Le travail présenté dans se manuscrit s'inscrit dans le domaine de la chimie et physico-chimie des polysaccharides. Une étude des propriétés physico-chimiques du xyloglucane en fonction de différentes conditions est d'abords réalisée, elle montre la difficulté d'obtenir des solutions stables à l'échelle moléculaire ainsi que la possibilité d'obtenir des nanoparticules à base de xyloglucanes. Le suivi de l'hydrolyse enzymatique du xyloglucane en solution par la diffusion de la lumière a mis en évidence l'agrégation des produits obtenus en solution. L'imagerie par la microscopie à force atomique a révélé l'importance de la surface dans le phénomène de dégradation. Enfin des dérivés de xyloglucane ont été obtenus par oxydation par le système TEMPO/NaOCl/NaBr, et des essais de préparation de conjugués xyloglucane-cytarabine ont été effectués.

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32

Aziz, Hany M. "Intrinsic degradation mechanism in Tris(8-hydroxyquinolato) aluminum-based organic light emitting devices /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0035/NQ66192.pdf.

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33

Lohan, Fiona. "Elucidating the molecular mechanism of TRIB2-mediated degradation of C/EBPa in AML." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/5605/.

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The pseudokinase TRIB2 is a potent AML oncogene, capable of inducing transplantable AML with a relatively short latency in murine models. Functionally, the oncogenicity of TRIB2 has been linked to its degradation of C/EBPα, a transcription factor necessary for regulation of HSCs, myeloid differentiation and is identified mutated in ~10-15 % of cytogenetically normal AMLs. Previously, we have demonstrated that elevated TRIB2 mRNA expression is associated with a subset of C/EBPα dysregulated AML patients. Here, using in vivo ubiquitination assays I determined TRIB2 exerts its effect through K48 specific ubiquitin-dependent proteasomal degradation of C/EBPαp42. Peptide array analysis identified the specific amino acids involved in the direct binding of these two proteins. Site-directed mutagenesis of these amino acids demonstrated that the direct binding of TRIB2 and C/EBPα was required for TRIB2-mediated C/EBPαp42 ubiquitination. C/EBPαp42 may exist as a dimer or a monomer; however differential dimerisation perturbs terminal myeloid differentiation. TRIB2 binds both monomeric and dimeric C/EBPαp42 but ubiquitination assays revealed it preferentially mediates ubiquitin-dependent degradation of dimeric C/EBPαp42, suggesting dimeric C/EBPαp42 provides a structurally preferential confirmation for TRIB2-mediated ubiquitination of C/EBPαp42. In order to determine if a post-translational modification of C/EBPαp42 was a trigger for TRIB2-mediated binding and degradation, I assessed the phosphorylation status of C/EBPα, often a modification involved in C/EBPα ubiquitination. I determined TRIB2 decreased the levels of phosphorylated Serine 21 (S21) C/EBPα through preferential binding to the phosphorylated S21 form of C/EBPαp42 and mediating increased ubiquitination. Further molecular elucidation of the TRIB2:C/EBPαp42 proteolytic relationship identified C/EBPαp42-K313 as the site of ubiquitin conjugation on C/EBPα and subsequent annotation of this region revealed it is mutated in ~10 % of C/EBPα mutAMLs. Using the clinically available proteasome inhibitor Bortezomib I investigated the targeted inhibition of the TRIB2 degradation function to induce cell death in AML cells. In TRIB2 overexpressing AML cell lines, and in AML patient samples identified to have elevated levels of TRIB2, I have demonstrated that high TRIB2 expressing samples are more sensitive than low TRIB2 expressing samples to cell death induced by proteasomal inhibition. I propose TRIB2 mediates is leukaemogenic effects through functioning as an adaptor protein, facilitating the formation of a multiprotein complex COP1:TRIB2:C/EBPα resulting in ubiquitin-dependent C/EBPαp42 degradation. Dimeric P-Ser21-C/EBPαp42 provides a structurally favourable confirmation for enhanced TRIB2-mediated ubiquitination. As C/EBPαp42 plays a key role in both stem cell function and myeloid differentiation in AML, the targeted inhibition of TRIB2-mediated C/EBPαp42 degradation may provide therapeutic avenues in AML.

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34

Popov, Vladimir, Vladimir Kaigorodov, Elena Popova, and Timofey Pavlov. "Mössbauer investigation of segregation and diffusion mechanism of 119m Sn in poly- and nanocrystalline Nb grain boundaries." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196087.

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35

Zhao, Yuan. "Identification and quantification studies on structures, dynamics and mechanism for thermal and photo-degradation products of β-carotene". University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1323736801.

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36

Soulas, Dimitrios N., and Kyriaki G. Papadokostaki. "Experimental investigation of the release mechanism of hydrophilic solutes from hydrophobic matrices." Diffusion fundamentals 11 (2009) 9, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A13929.

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37

Vergadou, Niki, and Doros N. Theodorou. "Microscopic diffusion mechanism of CO 2 in a glassy amorphous polymer matrix." Diffusion fundamentals 11 (2009) 11, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A13932.

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38

Yoshida, Masayuki, Hajime Kitagawa, Masami Morooka, and Shuji Tanaka. "Quantitative study of near equilibrium in dissociative mechanism of nickel in silicon." Diffusion fundamentals 9 (2009) 4, S. 1-16, 2009. https://ul.qucosa.de/id/qucosa%3A14142.

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The dissociative mechanism of nickel in silicon has been studied experimentally, assuming the near equilibrium represented by CiCV / Cs = Ci eq C eq / Cs eq , where subscripts i, V, and s represent interstitial nickel atoms, vacancies, and substitutional nickel atoms, respectively, superscript eq represents the thermal equilibrium, and CA is the concentration of component A. However, the assumption of the near equilibrium has not yet been verified experimentally, because it is difficult to measure CV in silicon. In the present work, the simultaneous diffusion equations of the dissociative mechanism of nickel in silicon are solved numerically by double-precision FORTRAN without assuming the near equilibrium under the condition of in-diffusion of nickel into a silicon specimen, and the establishment of the near equilibrium is verified. It is also clarified that the near equilibrium is a transitional process which continues until the thermal equilibrium is reached. After the near equilibrium is reached, the very small difference of two nearly equal terms is an important factor in solving the diffusion equations. In other words, high accuracy is necessary to solve the diffusion equations. Concerning this, it is verified that the accuracy of double-precision FORTRAN is sufficiently high to solve the diffusion equations in the present work.

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39

Мазурок, Наталия Степановна. "Физико-статистический метод определения надежности изделий твердотельной электроники". Doctoral thesis, Киев, 2013. https://ela.kpi.ua/handle/123456789/6457.

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40

Belova, Irina V., David Shaw, and Graeme E. Murch. "Limits of the ratios of tracer diffusivities for the vacancy-pair mechanism with application to compound semi-conductors." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190042.

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41

Chandra, Ashwini. "On the Mechanism of Niobium Electropolishing." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1330544777.

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42

Chen, Qu, Yingchun Liu, Qi Wang, and Keith E. Gubbins. "The role of hydrogen bond in mechanism of water diffusion in carbon nanotubes." Diffusion fundamentals 16 (2011) 65, S. 1-2, 2011. https://ul.qucosa.de/id/qucosa%3A13808.

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43

Clark, S. A. "The mechanism of uptake and intracellular fate of leupeptin in rat yolk sacs." Thesis, Keele University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376309.

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44

Hergemöller, Fabian [Verfasser], and Gerhard [Akademischer Betreuer] Wilde. "The interstitialcy diffusion mechanism in alkali feldspar / Fabian Hergemöller ; Betreuer: Gerhard Wilde." Münster : Universitäts- und Landesbibliothek Münster, 2018. http://d-nb.info/1158662874/34.

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45

Tahiri, Iljirion, and Rina Namira Dalimunthe. "Diffusion and Control Mechanism of Environmental Performance Management: Case of Volvo CE." Thesis, Linnéuniversitetet, Institutionen för ekonomistyrning och logistik (ELO), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-57339.

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Background: Trends for more sustainable and environmental friendly business practices have transformed many industries, especially Volvo CE as an OEM within heavy vehicle industry, where company needs to continuously innovate and develop environmental sustainability technologies. Volvo CE is trying to balance the cost and profit with environmental impact through engaging in sustainable operations and do it through the optimization of Environmental Performance Management (EPM). There is a need for Volvo CE to improve their whole supply chain throughout the entire tier of suppliers since the suppliers create a major value within company business and Volvo CE need to find the way on how to diffuse the EPM to supplier networks. Also, to control and evaluate the process, Volvo CE is looking for systematic control mechanism to measure and control the practice of EPM. Research questions: 1. How does the environmental regulation in heavy vehicle industry impact the EPM of Volvo CE? 2. How should the EPM be efficiently diffused to the supplier network of Volvo CE? 3. Which are the effective control mechanisms of the EPM on the supplier network of Volvo CE? Purpose: The purpose of this paper is two-fold. Firstly, it aims to identify the impact of environmental regulations has in Volvo CE. Secondly, it is set to analyse the possible ways to efficiently diffused the EPM on the supplier network of Volvo CE and identify control mechanisms for the EPM implementation on the supplier network, from the perspective of Volvo CE. Method: By using Volvo CE as the research object, this study adopts case study method with qualitative approach. The study is conducted in ii Volvo CE perspective where it has an abductive approach with the intention to examine the impact of environmental regulation in EPM of Volvo CE, understand how Volvo CE implement the diffusion back to the supplier network and control the process through EPM. Conclusion: The findings emphasize that the environmental sustainability regulations impact the EPM in Volvo CE are distributed in manufacturing/production, managerial, strategic, technical and compliance area. Volvo CE needs to work a lot with energy efficiencies, material efficiencies and waste reduction management and find the products, which need less energy to produce and environmental friendly. To achieve the efficient of EPM adoption, EPM should perceive to have relative advantage, compatibility, complexity, trialability and observability characteristic. The control mechanism can be built through formal and informal control techniques. Specifically, Volvo CE needs to identify more joint KPI:s with suppliers and include important suppliers in the process. A long-term relationship with an important supplier will alleviate the control of 2:nd and 3:rd tier supplier since the important supplier will have the trust and authority to control, monitor and oversee how they are implementing the environmental aspect in their daily work.

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46

Linero, Jiménez Adriano. "DEVELOPMENT OF A MODEL OF THE DEGRADATION OF THE MECHANICAL PROPERTIES OF POLYOXYMETHYLENE (POM) IN THE PRESENCE OF BIODIESEL." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-10160.

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This project analyses the impact in the mechanical properties of Polyoxymethylene (POM) of three different blends of biodiesels: B0 with 0% of Rapeseed Methyl-ester (RME), B20 with 20% of RME and B100 with 100% of RME. Polyoxymethylene specimens have been subjected to an accelerated aging during 1600 hours at 85ºC. This is the equivalent to 20 years of life time. In addition, a thermal oxidation in air at the same temperature has been performed to check the impact of the temperature in the final degradation.Three different methods have been performed to calculate the diffusion rate, however and one of them has been selected for its reliable results. The second Fick´s law have been chosen to model the diffusion. The diffusion rate has been calculated for the B20 and B100 blend due to the B0 blend has a non-constant diffusion rate. B20 shows also some divergence while B100 fits the Fickian behaviour.A Finite Different approximation method has been used to predict the concentration profiles of the diffusion process of B20 blend. They have been compared with the results of the IR Microscope, with a clear misalignment between the expected and the actual values.Tensile tests have been done in different stages of the test to check the stress-strain behaviour of the specimens for each aging type. The most relevant parameter of degradation is the Elongation At Break (EAB), which decrease considerably a cause of the embrittlement. A study of the real stress-strain has been also done to assure the real behaviour of the material.A fracture surface study through Scanning Electron Microscope (SEM) and Light Microscope has been done to assure the brittle behaviour with the aging and the changes in the structure of the material.The swelling behaviour has been also modelled, and the bases for a future FEM analysis have been exposed.

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47

Ouattara, Mahamoudou. "Molecular Mechanism of Heme Acquisition and Degradation by the Human Pathogen Group A Streptococcus." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/biology_diss/127.

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Heme is the major iron source for the deadly human pathogen, Group A Streptococcus (GAS). During infection, GAS lyses host cells releasing hemoglobin and other hemoproteins. This dissertation aims to elucidate the general mechanism by which GAS obtains and utilizes heme as an iron source from the host hemoproteins. GAS encodes a heme relay system consisting of Shr, Shp and the SiaABC transporter. We specifically determine the role of Shr in the heme uptake process, by conducting a detailed functional characterization of its constituent domains. We also undertake to solve the long-standing mystery surrounding the catabolism of heme in streptococci. The studies presented herein established Shr as a prototype of a new family of NEAT-containing hemoproteins receptors. They demonstrate its importance in heme acquisition by GAS and provide a molecular model for heme scavenging and transfer by the protein. We show that Shr modulates heme uptake depending on heme availability by a mechanism where NEAT1 facilitates fast heme scavenging and delivery to Shp, whereas NEAT2 serves as a temporary storage for heme on the bacterial surface. Finally, we identified and characterized for the first time, a heme oxygenase (HO) in the Streptococcus genus which was named HupZ. Sequence comparison between HupZ and several HOs from different structural families indicates that this enzyme is unrelated to any of the previously characterized HOs. However, orthologs of the protein are found in other important pathogens. The structure and the catalytic mechanism of HupZ suggest that it is the representative of a new family of flavoenzymes capable of degrading heme using their reduced flavin cofactor as a source of electrons. Overall, this work contributes significant knowledge to the topic of heme utilization by pathogens and importantly, provides new direct evidence that associates flavins with heme metabolism in bacteria. Thus it sets a new direction in the field and lays the ground for future fundamental and applied discoveries.

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48

Landes, Nico. "Vitamin E : elucidation of the mechanism of side chain degradation and gene regulatory functions." Phd thesis, [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975679473.

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49

Erlandsson, Bengt. "Influence of the degradation mechanism on the molecular weight changes for some degradable polymers /." Stockholm, 1998. http://www.lib.kth.se/abs98/erla0320.pdf.

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50

DeVor, Robert. "DETERMINATION OF THE DEGRADATION MECHANISM FOR POLYCHLORINATED BIPHENYL CONGENERS USING MECHANICALLY ALLOYED MAGNESIUM/PALLADIUM." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2856.

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Polychlorinated biphenyls are a ubiquitous environmental contaminant that can be found today throughout the world in soils and sediments, lakes and rivers, and flora and fauna. PCBs have percolated throughout the food chain, so that almost every human being has a detectable amount of the contaminant within their blood stream. Existing remediation methods include incineration, dredging and landfilling, and microbial degradation, but all of these methods have drawbacks that limit their effectiveness as treatment options. Recently, the use of zero-valent metals as a means of reductive dechlorination has been explored. Using a combination of zero-valent magnesium and catalytic palladium, a successful bimetallic system capable of degrading PCBs has been created and optimized. Determining the mechanism for the reductive dechlorination has proven to be an arduous task, but experimental evidence has suggested three possible radical-type mechanisms for the use Mg/Pd specifically in methanol (as compared to aqueous systems). These possible mechanisms differ in the type of hydrogen species that replaces the chlorine atom on the PCB. Thermodynamic information has also aided in narrowing down which of the suggested pathways is most likely. It appears likely that the hydrogen involved in the dechlorination has the form of a "hydride-like" radical, which is a form of electron-rich atomic hydrogen. According to the literature, Pd catalysts create this species within the first few subsurface layers of the palladium in the presence of molecular hydrogen. Further work will be necessary to confirm that the "hydride-like" radical is actually the species involved in the dechlorination.
Ph.D.
Department of Chemistry
Sciences
Chemistry PhD

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