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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.
11

Entwicklung von TRAIL-Fusionsproteinen und ihre Wirkung auf Myelomzellen

Berg, Daniela January 2008 (has links) (PDF)
1. Zusammenfassung Lösliche humane TRAIL-Varianten (hTRAIL), die nur die “TNF homology domain” (THD) beinhalten, binden sowohl den TRAILR1 aus auch den TRAILR2, stimulieren jedoch nur den TRAILR1. Nach sekundärem Quervernetzen des Liganden wird dann aber auch der TRAILR2 effektiv aktiviert. Entsprechende murine TRAIL-Varianten (mTRAIL) dagegen zeigen nur eine schwache Rezeptorbindung und sind selbst nach sekundärem Quervernetzen nur wenig aktiv. Interessanterweise kann ein Fusionsprotein aus der THD von mTRAIL und der Trimerisierungsdomäne von Tenascin-C (TNC), das wie mTRAIL selbst auch als Trimer vorligt, effizient an TRAIL-Rezeptoren binden und nach sekundärem Quervernetzen den TRAILR2 gut stimulieren. Weiterhin kann eine mTRAIL-Variante, die neben der THD auch die Stammregion des Moleküls enthält, die die THD von der Transmembrandomäne trennt, nach sekundärem Quervernetzen Apoptose induzieren, jedoch nicht so effektiv wie das TNC-mTRAILFusionsprotein. Die spezifische Bioaktivität der humanen TRAIL-Varianten wird gleichfalls, wenn auch weniger stark, durch Fusion mit der Tenascin-C-Trimerisierungsdomäne gesteigert. Die Fixierung des N-Terminus der THD, die hier durch die TNCDomäne sonst jedoch durch die Stamm- oder Transmembrandomäne gewährleistet wird, könnte demnach für mTRAIL für eine gute Rezeptorbindung und effektive Apoptoseinduktion nötig sein. Dies deutet auf eine bisher nicht erkannte Rolle der Stammregion für die Aktivität dieser Liganden hin und bietet die Möglichkeit, rekombinante lösliche Liganden der TNF-Familie mit erhöhter Aktivität zu generieren. Die TRAIL-induzierte Apoptose kann für die Behandlung von Tumorzellen nützlich sein. Es wurde jedoch kürzlich gezeigt, dass TRAIL neben Apoptose auch proinflammatorische, d. h. potentiell tumorfördernde Signalwege, insbesondere in apoptoseresistenten Zellen induzieren kann. Im Folgenden sollte untersucht werden, inwiefern TRAIL solche Signalwege in Myelomzellen stimuliert. Oligomerisiertes TRAIL kann bei allen analysierten Zelllinien Caspasen aktivieren und Apoptose induzieren. Werden die Zelllinien mit dem pan-Caspaseinhibitor ZVAD behandelt, kann die Caspase- Aktivierung bei allen Zellen blockiert werden, die Apoptoseinduktion jedoch nur bei zwei Zelllinien. Im Gegensatz dazu schützt ZVAD drei andere Myelomzelllinien nur partiell vor der TRAIL-induzierten Apoptose. Dies zeigt, dass TRAIL in Myelomzellen auch caspaseunabhängigen Zelltod induzieren kann. TRAIL induziert in den Myelomzellen auch proinflammatorische Signalwege wie den NFкB-, den JNK-, den p38- und den p42/44-Signalweg. Die Stimulation des JNK- und des p38-Signalwegs erwies sich hierbei in zelltypspezifischer Weise caspaseabhängig, die Aktivierung des NFкB- und p42/44-Signalwegs immer als caspaseunabhängig. Zusammenfassend geht aus diesen Ergebnissen hervor, dass zur Behandlung des multiplen Myeloms, TRAIL in Kombination mit anti-inflammatorisch wirkenden Mitteln eingesetzt werden sollte, insbesondere um mögliche proinflammatorische Nebenwirkungen durch TRAIL zu minimieren. / 2. Summary Variants of soluble human TRAIL (hTRAIL), encompassing solely the TNF-homology domain (THD), interact with TRAILR1 and TRAILR2, but they only stimulate TRAILR1 robustly. After crosslinking however, these ligands are also able to activate TRAILR2. Contrarily, the corresponding murine TRAIL variants poorly bind and activate their receptors even after crosslinking. Interestingly, a fusion protein consisting of the THD of mTRAIL and the trimerization domain of Tenascin-C (TNC) shows an effictive receptor binding and TRAILR2 activation after crosslinking. A variant of mTRAIL that not only contains the THD, but also the the stalk region, which seperates the transmembranedomain from the THD, does also induce apoptosis after crosslinking, but not as effective as the TNC-mTRAIL fusionprotein. The activity of soluble human TRAIL variants is also enhanced after fusion with TNC. It seems that especially for mTRAIL the spatial fixation of the THD by TNC is necessary for proper receptor binding and activation. This spatial fixiation is otherwise ensured by the stalk region or the transmembrane-domain. So the stalk region has unanticipated functions for the activity of the TNF ligands. Moreover, there is now an option to generate soluble ligands of the TNF-family with improved activity. TRAIL-induced apoptosis could be applied in the treatment of tumor cells. However, it was shown that TRAIL cannot only induce apoptosis, but also activates proinflammatory potentially tumor promoting pathways, especially in apoptosis resistant cells. Therefore, the ability of TRAIL to activate such pathways in myeloma cells was analyzed. Oligomerized TRAIL induces apoptosis and caspase activation in all analyzed myeloma cells. In experiments with the pan-caspase inhibitor ZVAD caspase acitvation could be blocked in all cell lines, but apoptosis could be blocked only in two cell lines. Three other myeloma cell lines were only marginally rescued from apoptosis. Therefore, TRAIL can also induce caspase independent cell death in myeloma cells. Beside apoptosis TRAIL also stimulates proinflammatory pathways like the NFкB-, the JNK, the p38- and the p42/44- pathway. Thereby, the activation of the NFкB- and p42/44-pathways is always caspase-dependent, but the induction of the p38- and JNKpathways is cell type specifically caspase-dependent. Thus, taken together for myeloma therapy TRAIL should be used in combination with anti-proinflammatory drugs to avoid potential side effects related to the proinflammatory properties of TRAIL.
12

The geography of the Oregon Trail in Nebraska

Krouch, Mildred. January 1933 (has links)
Thesis (M.A.)--University of Nebraska (Lincoln campus)--1933. / Title from title page image (viewed Aug. 5, 2003). Includes bibliographical references.
13

Linear Landscapes

Richard, Jacquelyn 06 July 2011 (has links)
A recreational urban trail runs through the city of Fredericton, New Brunswick with little interaction between adjacent buildings or the parallel riverfront of the Saint John River. As the two de?ning landscape elements extending throughout the city, the river and greenway, elements designed to link the two will become part of the same city-wide language. The potential for connections creates an opportunity for new public spaces: architecture which can extend the trail to physically bridge and support water and land recreation. The design will culminate with two reciprocal sites along opposite edges of the river that provide both functional and experiential public spaces for recreational river and trail users. The strategies made to enhance these formerly neglected or private spaces are designed with the intent that any point along the vast trail network could be similarly adapted.
14

Math trail : Enstudie om elevers uppfattningar av mathtrail i matematikundervisning

Callenberg, Nina, Johansson Andersson, Jessica January 2014 (has links)
Det finns ett problem angående vilka undervisningsmetoder som ska användas för att lyckas höja elevers kunskapsnivå i matematik. Denna studie görs för att undersöka math trails plats i matematikundervisning och då utifrån tre aspekter: de fem förmågorna, verklighetsanknytning och motivation. Math trail är en promenad där olika uppgifter genomförs längs vägen i syfte att upptäcka matematiken som finns runt omkring oss. Math trail kan ses vara en del av utomhuspedagogiken. På grund av att ingen forskning presenterats inom math trail väljer vi därför att lyfta fram forskning kring utomhuspedagogik. Många av dessa tidigare studier är gjorda utifrån lärares eller forskares perspektiv och därför väljer vi ett elevperspektiv. Syftet med studien är att beskriva elevers uppfattningar av att använda math trail i matematikundervisningen. Undersökningen görs kvalitativt där det empiriska materialet samlas in genom fokusgruppsamtal med elever från två högstadieklasser som genomfört ett math trail vi konstruerat. Materialet analyseras utifrån den fenomenografiska metoden och ger sex beskrivningskategorier: yttre omständigheter inverkar, lärares närvaro påverkar, gynnar samarbete, utmanande uppgifter, har nytta av samt variation från det ”vanliga”. Slutsatser som dras är kopplade till de tre aspekterna av matematikundervisning. Eleverna har uppfattningen att de får öva på alla fem förmågorna i ett math trail. Eleverna har uppfattningen att math trail grundas i verkligheten, visar på en nytta av matematiken och leder till en insikt att matematik kan finnas överallt. Math trail, uppfattar eleverna, påverkar deras motivation genom att det är en variation från deras ”vanliga” lektioner, eleverna vill bidra till att gruppen klarar uppgifterna och de ser en användning av matematiken. Eleverna uppfattar även math trail som ett praktiskt inslag.
15

Modulation of death receptor-induced apoptosis by Hsp72

Clemons, Nicholas J Unknown Date (has links) (PDF)
The inducible heat shock protein Hsp72 inhibits apoptosis and promotes long term survival after a number of stresses but the mechanism by which this is achieved remains unclear. A role for Hsp72 in modulating apoptosis mediated through members of the TNF-receptor super family other than TNF-R1 has not been clearly established. Given the observations of high levels of Hsp72 in tumours of poor prognosis, we set out to determine whether Hsp72 could specifically modulate apoptosis induced through the death receptor pathways mediated by Fas and the TRAIL receptors. Both these pathways are of relevance in tumour surveillance. (For complete abstract open document)
16

An analysis of Kentucky trail riders determining rider behaviors and valuing site amenities that contribute to repeat visits /

Auchter, Katharine Anne, January 2008 (has links)
Thesis (M.S.)--University of Kentucky, 2008. / Title from document title page (viewed on February 3, 2009). Document formatted into pages; contains: viii, 72 p. : ill. (some col.), maps (some col.). Includes abstract and vita. Includes bibliographical references (p. 69-71).
17

TRAIL signalling regulation by ezrin / Régulation de la signalisation TRAIL par l'ezrine

Iessi, Elisabetta 29 November 2011 (has links)
Objectifs: La cytokine TRAIL (TNF Related Apoptosis Inducing Ligand) suscite un intérêt majeur en thérapie anti-cancéreuse grâce à sa capacité à induire l’apoptose des cellules cancéreuses tout en épargnant les cellules saines. L’association du récepteur Fas et de l’actine via l’ezrine, une protéine de la famille ERM (Ezrin, Moesin, Radixin), régule les premières étapes de l’induction de l’apoptose par FasL. Au cours de mon projet de thèse, nous avons voulu déterminer le rôle que pouvait jouer l’ezrine au cours de l’apoptose induite par TRAIL, dans des lymphomes B ou des cellules cancéreuses adhérentes (HeLa, HCT116 et SW480). Matériel et Méthodes: Des approches biochimiques et moléculaires nous ont permis d’étudier et de déterminer l’implication de l’ezrine et sa phosphorylation dans la régulation de la mort induite par TRAIL. Résultats: Ce travail démontre que l’ezrine peut réguler de manière négative l’apoptose induite par TRAIL et FasL. Cette activité inhibitrice est régulée par la phosphorylation/déphosphorylation sur la serine 66 ainsi que sur la thréonine 353. Néanmoins cette régulation n’affecte ni la formation, ni l’activation du DISC (Death Inducing Signalling Complex). Des mutations de ces résidus par une alanine (S66A) ou un acide aspartique (Y353D) augmente sélectivement la capacité de TRAIL à induire l’apoptose. Au contraire, des mutations ponctuelles de ces résidus permettant de mimer la phosphorylation de l’ezrine sur la serine 66 (S66D) ou l’expression d’un variant non phosphorylable sur la thréonine 353 (Y353F) protègent les cellules cancéreuses de l’apoptose induite par TRAIL. De manière concordante, l’utilisation du H89, un inhibiteur de PKA, kinase responsable de la phosphorylation de la serine 66 augmente la sensibilité des cellules cancéreuses à TRAIL, alors qu’au contraire, un activateur de PKA (8bromocyclic AMP) rend ces mêmes cellules plus résistantes à TRAIL. Enfin, l’association de TRAIL et du cisplatine permet de dépasser l’inhibition de l’apoptose par l’ezrine. / Background and Aim: TRAIL has sparked a growing interest in oncology due to its ability to selectively trigger cancer cell death while sparing normal cells. The Fas/actin association through ezrin, a member of the ERM protein family, has been reported to regulate early steps of Fas-mediated apoptosis. In this project, we addressed the role of ezrin regarding TRAIL-induced cell death in B lymphoma cell lines, or adherent cancer cell lines (HeLa WT, HCT116, SW480). Methods: Molecular and biochemical approaches were employed to study the relevance of ezrin and its phosphorylation status in TRAIL signaling. Results: We found that ezrin displays a negative function towards TRAIL- and Fas-mediated apoptosis and that the ezrin-mediated TRAIL-induced cell death inhibition led to ezrin activation through phosphorylation/dephosphorylation events at serine 66 and tyrosine 353, but is mainly independent of TRAIL DISC (Death Inducing Signalling Complex) formation or activation. Mutations of these residues to alanine (S66A) or aspartic acid (Y353D) selectively enhanced TRAIL-induced cell death, whereas point mutations mimicking ezrin phosphorylation on S66 (S66D) or a nonphosphorylable variant on Y353 (Y353F) strongly protected cancer cells from apoptosis induced by TRAIL. Moreover, inhibition of the ezrin serine 66 PKA target site, using H89, increased cancer cell sensitivity to TRAIL, while treatment with 8bromocyclic AMP, a PKA activator, decreased TRAIL-induced cell death. In addition, combined TRAIL/cisplatin treatments abrogated ezrin-mediated inhibition of TRAIL-induced apoptosis.
18

Establishing a Biomarker of Cellular Aging for Mesenchymal Stem Cells and Investigating Their Regenerative Potential

January 2019 (has links)
archives@tulane.edu / 1 / Sean Madsen
19

Tranquillity trails – design, implementation and benefits for healthy leisure

Watts, Gregory R., Bauer, J. 15 July 2021 (has links)
Yes / Tranquillity trails (TTs) are designed to provide a quiet and peaceful walk through mainly leafy lanes and roads and connect green open spaces where visitors can stop for thought and relaxation. There are numerous health benefits from being in close proximity to nature and TTs can facilitate this contact in mainly urban areas. This study involved the design of a trail in Tramore, a coastal town in south east Ireland. The trail links an old coastguard station, now converted to a cultural centre and coffee shop, with a Japanese garden. The trail includes a coastal path with fine views across a bay, wooded areas as well as leafy residential streets. The design of the trail was facilitated by the use of a previous developed tranquillity rating prediction tool (TRAPT) that involved the estimation of the level of man-made noise and the percentage of natural features in view. Participants who had completed the whole of the trail were encouraged to complete a questionnaire to gauge any benefits. As expected, it was reported that there were increased levels of relaxation and reduced stress. It was concluded that the approach can be used elsewhere to improve the well-being of residents and visitors.
20

Reconsidering the Politics of Nature and Community on the Applachian Trail

McDonald, Bryan 28 April 1999 (has links)
This thesis explores the potential for communities to become involved in efforts to develop ecologically sustainable societies. As the concept of community is often ill defined, this thesis explores traditional and interest-based ideas of community, and develops a conceptualization of a work-based community. The history and development of the Appalachian Trail is reviewed as an example of how private citizens can reshape unbuilt environments through physical work and dedication to a common goal. Through the work of maintaining a 2,100-mile hiking trail, trail managers come to share common experiences and goals, as well as developing relationships with people and places that make it possible to recognize these maintainers as a work-based community. The A.T. management community exemplifies the potential for communities to have substantive in efforts to develop more ecologically sustainable and socially equitable ways for humans to live, work, and play in built and unbuilt environments. / Master of Arts

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