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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.
1

Essential 500 Wordlist for the Foundations Program at the Brigham Young University's English Language Center

Jung, Inho 15 April 2010 (has links) (PDF)
In order to help ESL students in the Foundations Program at BYU's ELC, I have developed a 500-word list of essential English vocabulary. This list attempts to reach one of the goals of the institute's curriculum, which is to develop systematic, integrated vocabulary instruction. Published literature reveals that studying with a list in conjunction with explicit instruction can enhance L2 vocabulary learning when the instruction is systematically integrated with other skills and activities. The literature also shows the importance of learning the most frequent and essential words first, which can be found in the General Service List and the Academic Word List according to learners' needs. In order to develop an essential vocabulary list of 500 words for the Foundations Program at the ELC, I used several strategies. First, to investigate which words in their textbooks the students use, I analyzed the graded readers and listening books required in the curriculum of the Foundations Program. Second, after investigating the texts of the textbooks, the second step was to conduct a survey in order to investigate learners' lexical knowledge. To develop a reliable survey, reliable research strategies were conducted. The first survey was conducted at the end of Fall Semester 2009. Following the first survey, the second survey was conducted at the beginning of Winter Semester 2010. The administration of the two surveys revealed the students' self-reported knowledge about specific vocabulary items in the lists. Following the administration and analysis of the two surveys, I generated the final 500-word list for the students in the Foundations Program at BYU's ELC. The words were based on the students' needs and knowledge, and were generated based on the essential words from the GSL and the AWL in order to meet the goals of the curriculum of the Foundations Program.
2

Synthesis and Evaluation of Stimulatory Properties of Glycolipids for Natural Killer T Cells

Long, Xiangtian 11 May 2009 (has links) (PDF)
Natural killer T cells (NKT cells) are a subset of T cells. They regulate a wide range of diseases including infection, tumor growth, and autoimmune diseases, through recognizing glycolipid antigens in the context of CD1d. An understanding of the scope of glycolipid antigens would facilitate use of this cell type in controlling immune responses. Till today, a lysosomal glycolipid, isoglobotrihexosylceramide (iGb3), is the only natural glycolipid that has been found to be recognized by both human and mouse NKT cells. To elucidate the molecular basis of this specific recognition, iGb3 variants were designed and prepared: i) replacement of the C26 acyl chain with shortened acyl chains; ii) replacement of the distal galactose with glucose and mannose; iii) replacement of the intermediate galactose with glucose; iv) replacement of the proximal glucose with galactose. Among these glycolipids, the iGb3 variants with shortened acyl chains are potent stimulators of NKT cells. The iGb3 variant with intermediate glucose also showed the ability to stimulate NKT cells, but this finding needs to be verified. Our findings support the specific recognition of iGb3 by NKT cells. The search for other natural glycolipid antigens focuses on glycolipids that are isolated from bacteria and parasites. Recently, glycosphingolipids (GSL-1, -3, and -4) isolated from the sphingomonodaceae family of bacteria were characterized. GSL-1 has been shown to be a potent stimulator of NKT cells. Moreover, it has been reported that GSL-4 is a stimulator as well. To verify the structures and stimulatory properties of GSLs, GSL-1 to -4 were prepared and tested for their abilities to stimulate NKT cells. The result that only GSL-1 can stimulate NKT cells suggests that synthesis of these higher order GSLs would be an immune evasion mechanism. Neutral glycosphingolipids from sheep-derived F. hepatica liver flukes, a causative agent of fascioliasis, were isolated and characterized. Their structures are closely related to iGb3. Among these glycolipids, neo-iGb4s could be truncated to iGb3 in the lysosome and thus stimulate NKT cells. To test this hypothesis, these glycosphingolipids were prepared and tested. None of these synthetic glycolipids stimulates NKT cells, which suggests that the secretion of these glycolipids by F. hepatica could be the result of the parasite-immune-evasion mechanism.
3

Chemical biology approaches to study toxin clustering and lipids reorganization in Shiga toxin endocytosis / Etude de la condensation et de la réorganisation des lipides lors de l’endocytose de la toxine de Shiga via une approche de biologie chimique

Gao, Haifei 12 November 2015 (has links)
La toxine bactérienne de Shiga se lie au glycosphingolipide (GSL) globotriaosylcéramide (Gb3) afin d’entrer par endocytose dans les cellules en utilisant une voie dépendante et indépendante de la clathrine. Dans la voie indépendante de la clathrine, la toxine de Shiga réorganise les lipides de la membrane de façon à imposer une contrainte mécanique sur la bicouche, conduisant ainsi à la formation de pic d’invagination d'endocytose profonds et étroits. Mécaniquement ce phénomène n’est pas encore compris, notamment il reste énigmatique, comment se traduisent les propriétés géométriques de l’agrégation des glycosphingolipides GSLS et de la toxine. Dans mon travail de thèse, via l’utilisation de la sous-unité B de la toxine de Shiga (STxB) comme un modèle, différentes espèces moléculaires de son récepteur Gb3 ont été synthétisés avec des structures délibérément choisis. Les études réalisées par imagerie de haute résolution et par la modélisation informatique ont permis d’élucider les contraintes mécano-chimique sous-jacente conduisant à une réorganisation efficace qui a pour résultat l’agrégation de la toxine et la réorganisation des lipides. En combinant des expériences de simulation sur ordinateur de dynamique des particules dissipatives (DPD) et des expériences sur des modèles de membranes cellulaires, nous avons fourni la preuve de l’induction d’une force de fluctuation-membrane, de type « force de Casimir », conduisant à l'agrégation des molécules de toxines associées à la membrane à des échelles de longueur mésoscoiques. Nous avons observé et mesuré, en outre la condensation lipidique induite par la toxine, quantitativement sur des monocouches de Langmuir en utilisant la réflectivité des rayons X (XR) et par la mesure de la diffraction des rayons X par incidence rasante (GIXD), fournissant ainsi une preuve directe de l'hypothèse que la toxine a le potentiel de réduire de façon asymétrique la surface moléculaire sur la partie membranaire exoplasmique, ce qui conduit à une déformation locale de la membrane. Durant ma thèse, nos efforts ont été consacrés à la réalisation de nouveaux glycosphinolipides (GSL) comme outils chimiques à visée biologique. Par ailleurs, une nouvelle stratégie de reconstitution de GSL fonctionnels sur la membrane cellulaire, basée sur une réaction de ligation de type « click » entre un glycosyl-cyclooctyne et un azido-sphingosine a été étudiée. Les résultats obtenus sur les cellules se sont avérés beaucoup moins efficace que ceux in vitro. Une poursuite de l'optimisation de cette méthodologie est actuellement en cours. Une sonde fluorescente du glycosphinolipide Gb3, marquée à l’Alexa Fluor 568 lui-même lié par l'intermédiaire d'un bras PEG-α à la position de la chaîne acyle, a été synthétisée. Cette sonde se lie à la STxB sur couche mince de TLC, mais pas sur des membranes modèles. D'autres améliorations sont discutées. / Bacterial Shiga toxins bind to the glycosphingolipid (GSL) globotriaosylceramide (Gb3) to enter cells by clathrin-dependent and independent endocytosis. In the clathrin-independent pathway, Shiga toxin reorganizes membrane lipids in a way such as to impose mechanical strain onto the bilayer, thus leading to the formation of deep and narrow endocytic pits. Mechanistically how this occurs is not yet understood, and notably how the geometric properties of toxin-GSLs complexes translate into function has remained enigmatic. In my thesis work, using the B-subunit of Shiga toxin (STxB) as a model, different molecular species of its receptor Gb3 have been synthesized with deliberately chosen structures, coupled with high resolution imaging and computational modeling, to understand the underlying mechano-chemical constraints leading to efficient toxin clustering and lipids reorganization. By combining dissipative particle dynamics (DPD) computer simulation and experiments on cell and model membranes, we provided evidence that a membrane fluctuation-induced force, termed Casimir-like force, drives the aggregation of tightly membrane-associated toxin molecules at mesoscopic length scales. Furthermore, toxin-induced lipid condensation was observed and measured quantitatively on Langmuir monolayers using X-ray reflectivity (XR) and grazing incidence x-ray diffraction (GIXD), thereby providing direct evidence for the hypothesis that the toxin has the potential to asymmetrically reduce the molecular area of the exoplasmic membrane leaflet, leading to local membrane deformation. During my PhD, effort was also invested to develop new GSL tools applied to the biological setting. A novel strategy based on the Cu-free click reaction between glycosyl-cyclooctyne and azido-sphingosine was designed with the goal to functionally incorporate GSLs into cellular membranes. Following the synthesis work, click reactions have been performed in solution and on cells. Compared to the former, results on cells were far less efficient. Further optimization is currently ongoing. A fluorescently labeled Gb3 probe with Alexa Fluor 568 coupled via a PEG linker to the α-position of the acyl chain, was synthesized, to which STxB bound on TLCs, but not on model membranes. Further improvements are discussed.
4

Vyhledávání ve videu / Video Retrieval

Černý, Petr January 2012 (has links)
This thesis summarizes the information retrieval theory, the relational model basic and focuses on the data indexing in relational database systems. The thesis focuses on multimedia data searching. It includes description of automatic multimedia data content extraction and multimedia data indexing. Practical part discusses design and solution implementation for improving query effectivity for multidimensional vector similarity which describes multimedia data. Thesis final part discusses experiments with this solution.
5

Structure-Activity Studies of Glycosphingolipids as Antigens of Natural Killer T Cells

Goff, Randal Donald 26 July 2006 (has links) (PDF)
Glycosphingolipids (GSLs), composed of a polar saccharide head and a lipophilic ceramide tail, are ubiquitous components of the plasma membrane of eukaryotic cells. They serve in many regulatory capacities and have antigenic properties towards natural killer T (NKT) cells of the innate immune system. Critical to the recognition of glycosylceramides by NKT cells are antigen presenting cells (APC), such as dendritic cells, which are responsible for binding, processing, and delivery of ligands to these lymphocytes. This event is mediated by CD1d, a major histocompatibility complex-like protein expressed on the surface of APCs, which binds GSL antigens by the ceramide moiety and presents the polar group to the T cell receptors of CD1d-restricted cells. The subsequent immune response involves NKT cell proliferation and emission of numerous cytokines, such as interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), resulting in the stimulation of the innate and adaptive immune systems through maturation of APCs, activation of T cells, and secretion of antibodies by B cells. To understand the structure-activity relationship between GSLs and NKT cell activity and the requirements for intracellular processing of antigens, analogs of the model compound alphaGalCer (KRN-7000) have been synthesized. These include fluorophore-appended 6”-amino-α-galactosylceramides and N-alkenoyl GSLs, such as PBS-57, a potent alphaGalCer surrogate useful in NKT cell stimulation studies. A nonantigenic beta-C-galactosylceramide has also been prepared as an inhibitor of these innate lymphocytes. To probe the potential for using NKT cells to bias the immune system between the proinflammatory TH1 response or the immunomodulatory TH2 mode, versions of alphaGalCer with shortened ceramides have been created. One of these truncated analogs, PBS-25, has successfully been cocrystallized with CD1d and the binary complex structure solved by X-ray crystallography. Synthetic glycosphingolipids derived from Novosphingobium capsulatum and Sphingomonas paucimobilis have also been made. In assays with classical Valpha14i/Valpha24i NKT cell lines, these Gram-negative bacterial antigens were recognized directly and specifically by host immune systems through CD1d-restriction, unlike GSL-deficient microbes (e.g., Salmonella typhimurium). A search for other GSL-bearing alpha-proteobacteria led to the discovery of another natural glycosphingolipid, an N-alkenoylphytosphingoid-alpha-galactoside, isolated from the outer membrane of Ehrlichia muris.
6

Neue Medien im Fremdsprachenunterricht / New Media in Foreign Language Classes: Conception of a media educational Class for German Teachers in Adult/Further education

Herrmann, Ines 03 August 2016 (has links) (PDF)
Die Arbeit bildet die fachwissenschaftlich gestützte Erziehung von Deutsch-als-Fremdsprachelehrkräften zur Medienmündigkeit ab. Dafür werden Vorstudien zu einem umfassenden Konzept zusammengefügt. Es werden drei Fachbereiche vernetzt: Lehrerbildung, Medienpädagogik und Deutsch als Fremdsprache. Der Konzeption abgeleitet ist eine mögliche Didaktik für neuere Technologien, die mit einem von der Autorin selbst erstellten Kursbaustein veranschaulicht wird.
7

Neue Medien im Fremdsprachenunterricht: Konzeption eines medienpädagogischen Kurses für Deutschlehrkräfte in der Erwachsenen-Weiterbildung

Herrmann, Ines 29 September 2015 (has links)
Die Arbeit bildet die fachwissenschaftlich gestützte Erziehung von Deutsch-als-Fremdsprachelehrkräften zur Medienmündigkeit ab. Dafür werden Vorstudien zu einem umfassenden Konzept zusammengefügt. Es werden drei Fachbereiche vernetzt: Lehrerbildung, Medienpädagogik und Deutsch als Fremdsprache. Der Konzeption abgeleitet ist eine mögliche Didaktik für neuere Technologien, die mit einem von der Autorin selbst erstellten Kursbaustein veranschaulicht wird.:1. Einführung 2. Forschungsstand 2.1. Aus- und Fortbildung von Deutschlehrkräften 2.1.1. Historische Aspekte 2.1.2. Situierung im Germanistik- und Lehramtsstudium 2.1.3. Situierung der Lehrerfortbildung 2.1.4. Neue Ansprüche und Konzepte der Lehrerfortbildung 2.2. Medienpädagogik 2.2.1. Mediensozialisation 2.2.2. Medienbildung 2.2.3. Medienkompetenz 2.2.4. Neue Medien 2.2.5. Mediendidaktik 2.2.6. Lernen & Lehren mit neuen Medien 2.3. Deutsch als Fremdsprache 2.3.1. Medienwissenschaft 2.3.2. Sprachlehr- und -lernforschung 2.3.3. Medien im Unterricht 2.4. Schlussfolgerungen 3. Rahmenanalyse und Begründung der zu erstellenden Kurskonzeption 3.1. Zielgruppenanalyse & Einordnung 3.2. Ergebnisanalyse vergleichbarer Studien und Kurse 3.2.1. Lektürebericht 3.2.2. Auswertung eines landeskundlichen Seminares 3.2.3. Überlegungen zu einem medienpädagogischen Seminar 3.2.4. Überlegungen zu einer Online-Lehrerfortbildung des Goethe-Instituts 3.3. Standards, Kriterien und zu beantwortende Fragen zu Kurs & Medien 4. Konzeption eines medienpädagogischen Kurses für Deutschlehrkräfte 4.1. Kursziel: Kompetenzen Kursteilnehmender 4.1.1. Auf inhaltlicher Ebene 4.1.2. Auf Ebene der Technologien 4.1.3. Auf Ebene didaktischer Konzepte 4.1.4. Auf Ebene der Medienkompetenz 4.1.5. Zusammenfassende Lernzielformulierung 4.2. Kursform: Blended Learning 4.2.1. Struktur & Didaktik 4.2.2. Lehr- und Lernvereinbarungen 4.2.3. Überprüfung des Lernerfolges 4.2.4. Qualitätsmanagement 4.3. Kursinhalt: Konkrete Technologien & Konzepte 4.3.1. Lernplattformen & Blogs 4.3.2. Podcasts 4.3.3. Digital Games 5. Grundlegung einer Didaktik für Neue Technologien 5.1. Kommentiertes Modell 5.2. Beispielablauf eines Kursbausteins 5.3. Eignung & Varianten 6. Schlussbemerkungen Anhang: Liste der Seminarweblogs zu „Landeskunde und neue Medien“ Abbildungsverzeichnis Quellen- und Literaturverzeichnis
8

An assessment of student's English vocabulary levels and an exploration of the vocabulary profile of teacher's spoken discourse in an international high school

Creighton, Graham Robert 10 1900 (has links)
In many international schools where English is the language of learning and teaching there are large percentages of students whose first language is not English. Many of these students may have low vocabulary levels which inhibits their chances of taking full advantage of their education. Low vocabulary levels can be a particular problem for students in mainstream classes where fluent English speaking teachers are using English to teach content areas of Mathematics, Science and History. Not only do students have to comprehend the low-frequency, academic and technical vocabulary pertaining to the subject, but they also need to know the higher frequency vocabulary that makes up general English usage. If students’ vocabulary levels fall too far below the vocabulary levels with which their teachers are speaking, then their chance of comprehending the topic is small, as is their chance of succeeding in their subjects. This study has two broad aims. Firstly, I have set out to assess the English vocabulary levels of students at an international school where English is the language of learning and teaching. The majority of students at this school do not have English as their first language. The second aim of this study is to explore the vocabulary profile of the teachers’ spoken discourse at the research school. By gaining a better understanding of the nature of teacher discourse – specifically the percentage of high, mid and low-frequency vocabulary, as well as academic vocabulary that they use – English as a Second Language (ESL) teachers will be in a stronger position to identify what the vocabulary learning task is and be able to assist students in reaching the vocabulary levels necessary to make sense of their lessons. This study revealed a large gap between the generally low vocabulary levels of ESL students and the vocabulary levels spoken by their teachers. As a result the need for explicit vocabulary instruction and learning is shown to be very important in English medium (international) schools, where there are large numbers of students whose first language is not English. / Linguistics and Modern Languages / M.A. (Applied Linguistics)

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