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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
541

Invasion of human type II pneumocytes by Burkholderia cepacia.

Keig, P.M., Ingham, E., Kerr, Kevin G. January 2001 (has links)
No / Burkholderia cepacia is known to invade and survive within respiratory epithelial cells. Previous studies have employed transformed cell lines and it is not known whether the bacterium is capable of manifesting the same phenomena in primary cell culture. Two strains of B. cepacia of environmental (NCTC 10661) and clinical origin (C1359) were examined for their ability to invade and survive (over a 24 h period) within type II pneumocytes in primary culture using a gentamicin¿ceftazidime antibiotic protection assay. Both strains of B. cepacia were capable of invasion of type II pneumocytes in primary culture. Strain C1359 was capable of multiplying intracellularly as indicated by a seven-fold increase in the numbers of bacteria from 4¿24 h, whereas strain 10661, although unable to replicate intracellularly, was found to survive in the pneumocytes for at least 24 h. Future studies on the invasiveness of B. cepacia can employ A549 cells as a valid surrogate for primary cell culture assays which are time-consuming, labour-intensive and expensive to perform.
542

Designing anticancer copper(II) complexes by optimizing 2-pyridine-thiosemicarbazone ligands

Deng, J., Yu, P., Zhang, Z., Wang, J., Cai, J., Wu, Na, Sun, H., Liang, H., Yang, F. 26 May 2020 (has links)
Yes / To develop potential next-generation metal anticancer agents, we designed and synthesised five Cu(II) 2-pyridine-thiosemicarbazone complexes by modifying the hydrogen atom at the N-4 position of ligands, and then investigated their structure-activity relationships and anticancer mechanisms. Modification of the N-4 position with different groups caused significant differences in cellular uptake and produced superior antitumor activity. Cu complexes arrested the cell cycle at S phase, leading to down-regulation of levels of cyclin and cyclin-dependent kinases and up-regulation of expression of cyclin-dependent kinase inhibitors. Cu complexes exerted chemotherapeutic effects via activating p53 and inducing production of reactive oxygen species to regulate expression of the B-cell lymphoma-2 family of proteins, causing a change in the mitochondrial membrane potential and release of cytochrome c to form a dimer with apoptosis protease activating factor-1, resulting in activation of caspase-9/3 to induce apoptosis. In addition, Cu complexes inhibited telomerase by down-regulating the c-myc regulator gene and expression of the human telomerase reverse transcriptase. / Natural ScienceFoundation of China (31460232, 21431001, 21561017, 21462004),the Natural Science Foundation of Guangxi (2017GXNSFEA198002,AD17129007), IRT_16R15, Guangxi“Bagui”scholar program to HBSun, and High-Level Innovation Team and Distinguished Scholarprogram of Guangxi universities to F Yang.
543

Investigations into the pre-treatment methods for the removal of nickel (II) and vanadium (IV) from crude oil

Ikyereve, Rose E. January 2014 (has links)
The efficacy of using zeolitic materials for the removal of nickel (II) and vanadium (IV) ions from solution has been evaluated in order to provide a method for the removal of the metal ions during hydroprocessing of crude oil. Batches of sodium based zeolites with a variety of pore sizes and Si/Al ratios were prepared using standard methods (high causticity solutions and templating agent). Characterisation of the products was carried out using powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis to confirm the presence of single zeolitic phases (zeolite A, zeolite X, zeolite Y, sodalite Na8 [AlSiO4]6Cl2 and hydrosodalite Na6 [AlSiO4]6. 6H2O). In a batch exchange process, divalent nickel and tetravalent vanadium ion solutions of concentration range 0.01M - 0.1M were placed in contact with the zeolite samples at 110°C for a period of 24h. Nickel (II) exchange was found to occur for all the zeolites at concentrations considered. Zeolite X was found to be most efficient at removing nickel from the solutions while zeolite Y was least efficient. Characterisation of zeolite X after ion exchange using powder X-ray diffraction and scanning electron microscopy showed that the structure of the zeolite had been maintained. Simplistic modelling of powder X-ray diffraction data have shown that the nickel ions are preferentially substituted on one of the four sodium sites. Vanadium (IV) exchange was also found to occur for all the zeolites at the concentrations considered. Zeolite A was found to be most efficient for the vanadium uptake. Characterisation with PXRD, FTIR and SEM-EDS however, shows that in addition to exchange at the zeolite s normal cation exchange sites, a significant amount of framework silicon species were also exchanged by the vanadium ions thus having a destructive effect on the zeolite framework leading to structural collapse. Ion exchange of the sodium-based zeolites with potassium and lithium showed that the uptake of nickel and vanadium of the zeolites significantly increased compared to the as- synthesised zeolites. Zeolite Y was surface-modified with the APTES ligand and showed a similar trend to that observed for alkali metal-zeolites; showing significantly greater nickel uptake at lower concentrations. Nickel-tetraphenylporphrin was synthesised as a mimic for the nickel-asphaltenes found in crude oil and an α-hydrogen donor solvent used to remove the nickel in the presence of zeolite ion exchangers. A similar trend was observed to that seen in aqueous solution, implying the process would be transferrable to a live medium. Analysis to determine the metal ions present in ashed Nigerian crude samples before and after solvent and/or complexing agent extraction was carried out using inductively coupled plasma mass spectroscopy (ICPMS) and energy fluorescence analysis by X-rays (XRF). The process showed varying amounts of nickel was extracted by the different media along with iron. For nickel, the extent of extraction in the order of increasing % extraction is H2O<H3PO4<EDTA<IPA. For iron the order of increasing % extraction was H2O=EDTA<H3PO4<CH3OH while zinc extraction was in the order H2O<H3PO4 <CH3OH=EDTA.
544

Kvinnors upplevelse av att leva med diabetes mellitus typ II : en litteraturöversikt

Gyllström, Frida, Sjöberg, Angelica, Strid, Jenny January 2016 (has links)
Bakgrund: Diabetes mellitus är ett växande folkhälsoproblem då allt fler insjuknar i sjukdomen. Det är en kronisk sjukdom och förekommer i två olika typer, typ I och typ II varav typ II är den mest utbredda. Övervikt är en bidragande orsak till att personer utvecklar diabetes mellitus typ II, därför är det viktigt att göra livsstilsförändringar när diagnosen erhållits. Det är betydelsefullt att som sjuksköterska hjälpa och stödja personer utifrån deras behov. Syfte: Att beskriva kvinnors upplevelser av att leva med diabetes mellitus typ II. Metod: En litteraturöversikt med kvalitativ design där 16 artiklar har analyserats och sammanställts till ett resultat. Resultat: Flertalet kvinnor upplevde en ökad oro och stress över hur de skulle hantera sin sjukdom. Det fanns flera olika faktorer som påverkade hur kvinnorna skötte sin sjukdom. För att de skulle förändra sin vardag och genomföra livsstilsförändringar var det nödvändigt med kunskap och information. Slutsats: För att hantera sin sjukdom krävs adekvat information ifrån hälso- och sjukvården. Brist på adekvat information kan visa på att det inte finns så stor kompetens kring sjukdomen. För att kunna optimera vården är det viktigt att som sjuksköterska ha kunskap om hur sjukdomen upplevs. / Background: Diabetes mellitus is a growing public health problem as more fall ill with the disease. It is a chronic disease and occurs in two types, type I and type II, which type II is the most widespread. Obesity is a contributing factor to people developing diabetes mellitus type II, so it is important to make lifestyle changes when diagnosed been acquired. It is significant as a nurse to help and support people based on their needs. Aim: To describe women's experience of living with diabetes mellitus type II. Method: A literature review where a qualitative design has been implemented, 16 articles have been analyzed to the result. Results: Most women experienced increased anxiety and stress over how to manage their disease. There were several factors that influenced how women managed their disease. To change their daily lives and to implement lifestyle changes, it was necessary to have knowledge and information. Conclusion: To manage their condition it requires adequate information from healthcare. Lack of adequate information can demonstrate that there is not so much expertise about the disease. In order to optimize the care it is important that as a nurse to have knowledge of how the disease is experienced.
545

Betydelsefulla framgångsfaktorer vid implementering av finansiella regelverk : En studie inför implementeringen av MiFID II  för finansiell rådgivning och  investeringstjänster

Noresson, Josefine, Neziri, Krenare January 2016 (has links)
Denna uppsats syftar till att förklara och förstå de centrala faktorer som är av betydelse vid en implementering av ett finansiellt regelverk. Ett kvalitativt tillvägagångssätt har använts för att uppnå vårt syfte, genom att intervjua olika respondenter från olika typer av finansiella företag som står inför den kommande förändringen. Genom att kombinera vårt empiriska resultat med den framtagna teorin om implementeringar, har vi kunnat komma fram till faktorer som är av betydelse vid implementeringar av finansiella regelverk.  De mest betydelsefulla faktorerna för en framgångsrik implementering av finansiella regelverk är anpassningsbarhet, analysförmåga och kommunikation. Genom att redan tidigt följa regelverkets utveckling kan organisationen ha en god uppfattning om hur det senare kommer att utformas på en nationell nivå. På detta sätt blir inte implementeringsprocessen lika begränsad av den långa tid som det tar att stifta de nationella regleringarna. Det är väsentligt att organisationerna kan anpassa sin implementeringsmetod utifrån regelverkets innehåll, men även anpassat till dagens moderniseringen av tekniken. När det gäller att implementera regelverk är det oftast direkt kopplat till de utgivna tjänsterna, vilket sätter mer vikt på medarbetarnas kunskap och förståelse vid en sådan implementering. / This study seeks to explain and understand the key factors that are important when implementing a financial regulation.        A qualitative approach has been used to achieve our purpose, by interviewing different respondents from different types of financial companies facing the coming change. By combining our empirical results with the developed theory of implementations, we´ve been able to find factors that are important when implementing financial regulations.  The most important factors for a successful implementation of financial regulations are adaptability, analysis capability and communication. By following up early with the regulatory developments, the organization can have a good idea of ​​what it will look like when it’s finalized on a national level. In this way, the implementation process will not be limited by the long time that it takes to enact the national regulations. It is essential that organizations can adapt their implementation method based on the content of the regulation, but also adapt it to today's modernized technology. When it comes to implementing regulations, it is usually directly related to the services that are being offered, which puts more emphasis on the employees' knowledge and understanding.
546

Studies of native and Cd(II)-substituted carbonic anhydrases with special reference to their interaction with inhibitors

Tibell, Lena January 1984 (has links)
The major aim of this work has been to gain further insights into the catalytic mechanism of carbonic anhydrase (carbonate hydro-lyase, EC 4.2.1.1). One approach has been to replace the essential Zn(II) ion by Cd(II) which has favourable spectroscopic properties. The Cd(II)-enzymes have appreciable 4-nitrophenyl acetate hydrolase activities. These activities increase with pH as if dependent on the basic form of a group with pKa near 10. The Cd(II)-carbonic anhydrases also have significant carbon dioxide hydration activities. Jhe Cd(II) derivatives are strongly inhibited by monovalent anions. The 113-Cd(II) derivatives have also been studied by 113-Cd NMR as a function of pH and bicarbonate or inhibitor concentration. Plots of chemical shift versus pH give sigmoidal titration curves in the studied pH range, 10.3. The p«a values vary from 9.2 to 9.7 correlating reasonably well with the activity profiles. When bicarbonate is added to the samples the 113-Cd resonances shift upfield to new characteristic positions. The inhibitors CN", SH", and SCN” bind directly to the metal ion with their C, S, and N atoms, respectively. The results are best explained by assuming a rapid exchange between three species in which the open coordination site of the metal ion is occupied by'hydroxide, water, or bicarbonate. Another approach has been to study kinetic properties of the active en­zyme. A number of monovalent anions were investigated as inhibitors of carbon dioxide hydration catalyzed by human carbonic anhydrase II. Predominantly uncompetitive inhibition patterns were observed at pH near 9 in all cases. The inhibition of human carbonic anhydrase II by the organic compounds tetrazole, 1,2,4-triazole, 2-nitrophenol, and chloral hydrate was also investigated. These inhibitors, together with phenol, can be classified in three groups depending upon the kinetic patterns of inhibition of carbon dioixde hydration at pH near 9. The first group, represented by tetrazole and 2-nitrophenol, yields predominantly uncompetitive inhibition under these conditions in analogy with simple, inorganic anions. The second group, represented by 1,2,4-triazole and chloral hydrate gives rise to essentially noncompetitive inhibition patterns whereas phenol, representing the third group, is a competitive inhibitor of carbon dioxide hydration. These results are analyzed in terms of two rivaling mechanism models, a kinetic scheme originally proposed by Steiner et al. (Eur. 3. Biochem. (1975) 59, 253-259) and a rapid-equilibrium kinetic scheme proposed by Pocker and Deits (3. Am. Chem. Soc. (1982) 104, 2424-2434). It is concluded that the observed steady-state inhibition patterns are compatible with both models, but hat discriminatory data, strongly favouring the model of Stêiner et al., are available in the literature. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1984, härtill 4 uppsatser</p> / digitalisering@umu
547

Identification de déterminants moléculaires de la liaison du récepteur et de l'urotensine II

Holleran, Brian January 2009 (has links)
Les récepteurs couplés aux protéines G (GPCRs) forment la classe de récepteurs la plus nombreuse et la plus étudiée. La compréhension du mode de fonctionnement de cette famille de récepteurs fait l'objet d'études intenses, tant au niveau de leur interaction avec le ligand qu'au niveau du processus d'activation suite à cette liaison. Le récepteur de l'U-II (UT) est un membre de la classe A des GPCRs et possède toutes les caractéristiques de cette famille. Notre hypothèse est que le récepteur UT possède des déterminants moléculaires identifiables qui sont impliqués lors de sa liaison à l'U-II et de son activation. Dans un premier temps, des études de marquage par photoaffinité du récepteur UT ont été effectuées en utilisant deux séries de ligands U-II qui contiennent le résidu photosensible para-benzoyl-L-phenylalanine (Bpa) et qui possèdent un caractère agoniste ou agoniste partiel. Il a été montré pour les deux séries de ligands que les quatre premiers résidus de l'U-II sont à proximité du résidu Met288 dans la 3e boucle extracellulaire du récepteur UT. Cette approche a également été utilisée pour comparer le patron de photomarquage entre deux ligands contenant le Bpa à la position 6, soit de l'analogue agoniste complet avec celui de l'analogue agoniste partiel. Il a été montré que le peptide agoniste photomarque les résidus Met184/Met185 du TMD4 de l'UT, tandis que l'agoniste partiel photomarque plutôt une région délimitée au TMD5. Le deuxième objectif du projet a été l'identification, au moyen de l'approche SCAM (Substituted Cysteine Assessibility Method) de résidus qui bordent la pochette de liaison du récepteur. Chacun des résidus des domaines transmembranaires 6 et 7 ont été mutés, un à un, par une cystéine. Suite au traitement par des composés MTS, la liaison du ligand [indice supérieur 125]I-U-II aux mutants F268C[indice supérieur (6.44)], W278C[indice supérieur (6.54)] et A282C[indice supérieur (6.58)] du TMD6 ainsi qu'aux mutants L298C[indice supérieur (7.34)], Y300C[indice supérieur (7.36)], T302C[indice supérieur (7.38)] et T303C[indice supérieur (7.39)] du TMD7 a été inhibée, démontrant que ces positions du récepteur font face à la pochette de liaison. L'ensemble de ces études mène à une meilleure compréhension des bases moléculaires de la liaison et de l'activation du récepteur UT et nous a permis de proposer un modèle moléculaire du récepteur UT ligandé. Ce modèle pourra ouvrir la voie vers une meilleure compréhension du processus de liaison et d'activation des GPCRs peptidergiques de la classe A.
548

Study of thermal neutron flux from SuperKEKB in the Belle II commissioning detector

Dejong, Samuel Rudy 31 May 2017 (has links)
The Belle II detector is designed to collect data from the high luminosity electron-positron (e$^+$e$^-$) collisions of the SuperKEKB collider. It will explore the flavour sector of particle physics through precision measurements. The backgrounds of particles induced by the electron and positron beams will be much higher than in any previous \epem collider. It is important that these backgrounds be well understood in order to ensure appropriate measures are taken to protect the Belle II detector and minimize the impact of the backgrounds. In February 2016 electron and positron beams were circulated through the two 3 km vacuum pipe rings without being brought into collision during `Phase I' of SuperKEKB commissioning. Beam backgrounds were measured using Belle II's commissioning detector, BEAST II. BEAST II is composed of several small subdetectors, including helium-3 thermal neutron detectors. The BEAST II thermal neutron detector system and results from its Phase I running are presented in this dissertation. The Phase I experiment studies beam-gas interactions, where beam particles collide with residual gas atoms in the beampipes, and beam-beam interactions, where beam particles interact with each other. Simulations of these two types of backgrounds were performed using the Strategic Accelerator Design (SAD) and GEometry And Tracking (GEANT4) software packages. A method to account for the composition of the gas in the beampipes was developed in order to correctly analyse the beam-gas component of the background. It was also determined that the thermal neutron rates in the data on the positron beam were 2.18$^{+0.44}_{-0.42}$ times higher than the simulation of beam-gas interactions and 2.15$^{+0.34}_{-0.33}$ times higher for beam-beam interactions. The data on the electron beam were 1.32$^{+0.56}_{-0.36}$ times higher for beam-gas interactions and 1.91$^{+0.54}_{-0.48}$ time higher for beam-beam interactions. The impact of these studies on Belle II is discussed. / Graduate / samdejong86@gmail.com
549

Etude de pigments thermochromes autour du cobalt II / Synthesis and characterization of new irreversible cobalt doped thermochromic pigments

Robertson, Lionel 09 December 2010 (has links)
Ce travail porte sur la synthèse et la caractérisation de nouveaux pigments thermochromes irréversibles avec le cobalt divalent pour chromophore principal en vue de les intégrer à une peinture thermosensible commerciale.Le travail a été réalisé en suivant trois phases. La première phase a consisté en l’identification de matrices thermosensibles présentant des évolutions structurales irréversibles en température dues à des transitions de phase du premier ordre ou des dégradations chimiques. Puis la synthèse de ces matrices a été effectuée par des voies compatibles avec les méthodes d’élaboration industrielle et permettant un dopage au cobalt. Enfin la troisième et dernière étape est l’étude in-situ et ex-situ des propriétés thermosensibles des pigments synthétisés à l’aide de techniques comme la diffraction des rayons X et des neutrons en température, l’analyse thermogravimétrique et la réflexion diffuse en température.À l’issue de ce travail de recherche, les solutions les plus efficaces ont été synthétisées à l’échelle industrielle puis intégrées à une peinture commerciale en phase aqueuse. / This work deals with the development of new thermochromic pigment which will be the active part of an irreversible thermochromic paint.The studies moved towards three steps. Firstly, an identification of crystalline matrix offering structural rearrangement in temperature because of first order phase transition or chemical degradation were performed. Then the identified matrix were synthesised thanks to synthesis routes compatible with industrial procedures. The third and last step consisted in the in-situ and ex-situ characterization of thermochromic properties of the synthesized compounds with technics like temperature coupled X-ray and neutrons diffraction, thermogravimetric analysis and temperature coupled diffuse reflectance analysis.The most efficient compounds were then industrially synthesized and integrated to a commercial aqueous paint.
550

Conception, synthèse et valorisation de spirolactames originaux mimant une hélice de type polyproline II / Design and synthesis of original spirolactams as first mimics of polyproline II helix

Coursindel, Thibault 22 November 2010 (has links)
Ces travaux de thèse s'inscrivent dans un projet à long terme visant à développer de nouveaux outils nécessaires à l'élucidation de mécanismes biologiques impliquant des interactions de type protéine-protéine mettant en jeu des structures secondaires protéiques de type polyproline II (PPII). En particulier, nous nous sommes intéressés à la conception, synthèse et valorisation de spirolactames originaux capables de mimer une hélice PPII, point de départ dans la recherche de nouvelles molécules d'intérêts thérapeutiques. Cette structure secondaire unique, caractéristique des ligands SH3, joue un rôle essentiel dans certaines activités biologiques telles que les phénomènes de reconnaissance, la transduction de signal, la transcription, la mobilité cellulaire, les réponses immunitaires et se trouve aussi impliquée dans des pathologies majeures telles que le SIDA, la Maladie d'Alzheimer et plusieurs tumeurs cancéreuses. Face à l'importance des structures secondaires PPII dans des cibles d'intérêt thérapeutique, dans les phénomènes de reconnaissance protéine-protéine, et face à l'absence dans la littérature de mimes PPII pertinents, ces travaux se sont attachés à l'élaboration et la valorisation d'outils PPII contraints, stables vis-à-vis de la dégradation protéasique. Ils nous ont tout d'abord permis de développer un accès stéréocontrôlé à une plateforme spiro [4,4] inédite, en nous appuyant sur une réaction de contraction de cycle développée récemment dans notre groupe, le réarrangement transannulaire de lactames activés (TRAL). Les études de dynamique moléculaire, et de dichroïsme circulaire nous ont permis de démontrer que certains des composés spiro synthétisés adoptent une structure "PPII-like", d'autres semblent au contraire se structurer en coude bêta. / This work is part of a long term project with the aim to develop new tools for the elucidation of biological mechanisms involving protein-protein interactions with the participation of the protein secondary structure named polyproline type II (PPII). In particular, we are interested in the design, the synthesis and the development of original spirolactams as first mimics of PPII helix, the starting point in the discovery of new compounds of therapeutic interest. This unique secondary structure, characteristic of SH3 ligands, plays a critical role in various biological activities such as the phenomena of recognition, signal transduction, transcription, cell motility, immune responses and is also involved in major diseases such as AIDS, Alzheimer's disease and several carcinogenic tumors. Regarding the importance of the PPII secondary structures in targets of therapeutic interest and in the phenomena of protein-protein recognition, and observing the absence in the literature relevant PPII mimics, this thesis have focused on the development of constrained PPII tools, stable versus protease degradation. This work first allowed us to develop an stereocontroled access to a novel spiro [4.4] scaffold, relying on a new ring contraction reaction recently developed in our group, namely transannular rearrangement of activated lactams (TRAL) . Studies of molecular dynamics, and circular dichroism have demonstrated that some of the synthesized spiro compounds adopt a "PPII-like" structure, others seems to be structured in beta-turn.

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