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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.
41

Habitat-Defining Genes and Synteny of Conditionally Dispensable (CD) Chromosomes in the Fungus Nectria Haematococca

Rodriguez, Marianela January 2006 (has links)
Individual isolates of the fungus Nectria haematococca exist in a wide range of habitats and part of this diversity is attributed to the presence of conditionally dispensable (CD) chromosomes that carry habitat-defining genes. In the current study a new factor located on one of these CD chromosomes was found. This trait allows pea pathogenic isolates of N. haematococca to grow in homoserine, a compound present in large amounts on pea root exudates. The gene(s) for homoserine utilization (HUT) are located on the same CD chromosome that carries the cluster of genes for pea pathogenicity, the PEP cluster. The PDA1 gene, a member of the PEP cluster, is routinely used as a marker for the presence of this CD chromosome, therefore it has been called the PDA1-CD chromosome. For the purpose of identifying the HUT gene(s), a physical map of the PDA1-CD chromosome was constructed. This map, in combination with synteny analysis, and Southern hybridizations led to the identification of a region of 365Kb that is likely to contain the HUT gene. By searching the publicly available genome of N. haematococca several candidates for HUT were identified.The synteny evaluation between the PDA1-CD chromosome and a different CD chromosome that carries the MAK1 gene, for chickpea pathogenicity, revealed a region (> 463Kb) of synteny, which advocates for a common ancestor for these CD chromosomes. However a large region (~ 1 Mb) in each of the CD chromosomes was found to carry unique DNA, therefore we proposed that individual isolates of this fungus contain large regions of unique DNA located on the CD chromosomes. The localization of syntenic regions also suggests that breakage points previous identified in the MAK1-CD chromosome could potentially be "hot spots" for recombination between both CD chromosomes. Furthermore, the anchoring of the PDA1-CD map to the genome of N. haematococca allowed the identification of additional putative habitat colonization genes present on both CD chromosomes, and niche-defining genes on the PDA1-CD chromosome.
42

Investigating the effects of nanoparticles on reproduction and development in Drosophila melanogaster and CD-1 mice.

Philbrook, Nicola 17 September 2012 (has links)
Manufactured nanoparticles (NPs) are a class of small ( ≤ 100 nm) materials that are being used for a variety of purposes, including industrial lubricants, food additives, antibacterial agents, as well as delivery systems for drug and gene therapies. Their unique characteristics due to their small size as well as their parent materials allow them to be exploited in convenience applications; however, some of these properties also allow them to interact with and invade biological systems. Few studies have been performed to determine the potential harm that NPs can inflict on reproductive and developmental processes in organisms. In this study, Drosophila melanogaster and CD-1 mice were orally exposed to varying doses of titanium dioxide (TiO2) NPs, silver (Ag) NPs, or hydroxyl-functionalized carbon nanotubes (fCNTs) and Drosophila were also exposed to microparticles (MPs) as a control for particle size. The subsequent effect of these materials on reproduction and development were evaluated. Strikingly, each type of NP studied negatively affected either reproduction or development in one or both of the two model systems. TiO2 NPs significantly negative effected both CD-1 mouse development (100 mg/kg or 1000 mg/kg) as well as Drosophila female fecundity (0.005%-0.5% w/v). Ag NPs significantly reduced mouse fetus viability after prenatal exposure to10 mg/kg. Ag NPs also significantly decreased the developmental success of Drosophila when they were directly exposed to these NPs (0.05% - 0.5% w/v) compared to both the vehicle and MP controls. fCNTs significantly increased the presence of morphological defects, resorptions and skeletal abnormalities in CD-1 mice, but had little effect on Drosophila. We speculate that the differences seen in the effects of NP types may be partially due to differences in reproductive physiology as well as each organism’s ability to internalize these NPs. Whereas the differing response of each organism to a NP type was likely due in part to varying durations of exposure. Since NPs are a popular commodity in today’s consumer world, the research presented here accentuates the need for further studies on the detrimental effects that these particles may have on a variety of developing organisms and on female reproductive health. / Thesis (Master, Environmental Studies) -- Queen's University, 2010-09-20 17:57:59.343
43

A survey of networked and compact disc technologies and applications for interactive music systems

Terriah, Sean C. January 1995 (has links)
The proliferation of the Internet and the convergence of telecommunication, computing, compact disc, and media technologies have paved the infrastructure for new interactive music environments. It is essential for those in the field of new media to be aware of the ramifications of these developments. Furthermore, there has been a growing interest among new media developers to provide the tools necessary to allow an end-user to take an active role in the outcome of an interactive multimedia presentation. This concept introduces the notion of end-user as artist and collaborator. This concept introduces the notion of end-user as artist and collaborator. This thesis investigates the diverse applications and technologies that have emerged through cross-disciplinary collaboration and how they may be used to specify and design innovative musical environments.
44

A study of MRP1-drug interactions : identification of the drug binding site(s)

Daoud, Roni N. January 2000 (has links)
Over-expression of either P-gp1 and/or MRP1 in tumor cell lines confers resistance to structurally diverse anti-cancer drugs. Although the role of these two proteins in clinical drug resistance remains to be confirmed, the use of Pgp1-specific inhibitors in combination with standard anti-cancer drugs have demonstrated significant improvement in clinical response. However, evidence exists that reversal of P-gp1 alone is not sufficient. Therefore, while no drugs are currently available that can efficiently reverse MRP1 drug efflux in tumor cells, there is an urgent need to develop MRP1-specific blockers. In an effort to gain a better understanding of MRP1-drug interactions and to identify sequences within MRP1 that interact directly with drugs, we developed two structurally diverse photosensitive drug analogues, a quinoline-based compound (IACI) and a xanthone-derivative (IAARh123). Both compounds photolabeled MRP1 and showed a direct and specific interaction with the protein at physiologically relevant sites. Initial mapping of photolabeled sequences in MRP1 (Chapters 2 and 3), identified multiple IACI- or IAARh123-photolabeled peptides (∼4--7 kDa) derived from both the N-terminal (MSD0+MSD1+NBD 1) and C-terminal (MSD2+NBD2) domains of MRP1. A subsequent study (Chapter 4), using MRP1 variants with hemagglutinin (HA) epitopes inserted at eight different locations, led to a higher resolution mapping of the previously identified IACI- or IAARh123-labeled peptides. Specifically, two photolabeled peptides (∼6--7 kDa), derived from variants with insertions at positions 574 and 1222, were immunoprecipitated with anti-HA monoclonal antibody. Based on the location of the HA epitopes in the latter variants together with molecular masses of the two peptides, the photolabeled amino acid residues were localized to MRP1 sequences encoding transmembranes 10 and 11 of MSD1 and transmembranes 16 and 17 of MSD 2. Interestingly, the same sequences were photolabeled with both
45

Universitätsbibliographie 1994 - 1996

Universität Potsdam, UB January 1999 (has links)
Die Universitätsbibliographie der Universität Potsdam enthält alle der Universitätsbibliothek gemeldeten Veröffentlichungen von Einzelmitgliedern der Universität Potsdam sowie der Universität als Korporation aus dem Zeitraum von 1994 bis 1996.
46

Large Scale Triaxial Testing of Mechanically Stabilized Earth Retaining Wall Backfill

Garton, Mackenzie 02 October 2013 (has links)
The use of mechanically stabilized earth (MSE) retaining walls has become quite prevalent in highway embankment applications. A design criterion for these walls was originally established by the Federal Highway Administration (FHWA) and has been modified on a state by state basis. Recently, the Texas Department of Transportation (TxDOT) has recorded several wall failures mostly due to excessive settlement and lateral wall deformation and wanted to evaluate the current state design guidelines for regionally available backfill materials. Prior to numerical modeling simulations, material parameters of regionally available backfill needed to be evaluated. As the state guidelines require 85-percent of the wall backfill material to be above the No. 4 sieve, large scale triaxial testing was an option to evaluate strength and volume change parameters. This research used cylindrical specimen 6-inches in diameter and 12- inches in height in a large scale triaxial apparatus. Three types of backfill material were tested and specimens were mixed and compacted in 4 different gradations for each material type. Each gradation was tested at confining stresses corresponding to wall heights of 10, 15, and 20 feet for a total of 36 tests. Basic material parameters such as unit weight and friction angle were evaluated directly from testing, while more complex material parameters were selected from the data for use in the Duncan-Chang elastic constitutive model. This method utilizes hyperbolic curve fitting of both strength and volumetric test data to define soil behavior parameters which include the following: modulus number (K), modulus exponent (n), initial tangent modulus (Ei), failure ratio (Rf ), initial Poisson’s Ratio (νi), and Poisson’s Ratio Parameters G, F, and d. Friction angles from triaxial testing ranged from 32 to 53 degrees having some uncertainty due to inconsistent compaction. The variation in sand and fine size particles in the backfill tended to reduce friction angles, except in the case of Type-B material where density increased due to the high percentage of sand and fines. Duncan-Chang parameters fit reasonably well with experimental data for strength barring some experimental errors. Volumetric parameters were inconclusive due to inconsistent compaction and membrane leakage. Additional testing is needed to provide more sound volumetric data.
47

Nutzung und Gestaltungsmöglichkeiten von Multimedia-CD-ROMs in der Marketing-Kommunikation mit Konsumenten dargestellt am Beispiel multimedialer CD-ROM-Anwendungen zur Produktionskommunikation im Automobilmarketing

Jarzina, Klaus Rüdiger January 2005 (has links)
Zugl.: Kassel, Univ., Diss., 2005
48

Studies of CD44 variant isoform expression and function on activated human peripheral blood mononuclear cells and in renal transplantation /

Varelias, Antiopi. January 2001 (has links) (PDF)
Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine, 2001. / Errata slip inserted at back. "August 2001." Includes bibliographical references (leaves 254-296).
49

Structural and functional determinants of effective CD8⁺ T cell suppression of HIV-1 replication

Simons, Brenna Colleen. January 2009 (has links)
Thesis (Ph. D. in Microbiology and Immunology)--Vanderbilt University, May 2009. / Title from title screen. Includes bibliographical references.
50

CEACAM1 : a common regulator of fat metabolism and cell proliferation

Lee, Sang Jun. January 2008 (has links)
Dissertation (Ph.D.)--University of Toledo, 2008. / "In partial fulfillment of the requirements for the degree of Doctor of Philosophy in Biomedical Sciences." Title from title page of PDF document. Bibliography: p. 74-82, 116-124, 146-192.

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