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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.
21

APSEN Analysis for Beyond 3G Wireless Networks / APSEN Analysis for Beyond 3G Wireless Networks

QADEER, MUHAMMAD, KHAN, MUHAMMAD HUMRAN January 2009 (has links)
The beyond 3G official IEEE name for next generation of wireless technology, some people also called it as 4G (fourth-generation) mobile communication systems. Beyond 3G will be used largely to contain not only cellular telephone systems but also several types of broadband wireless access communication systems, have been attracting much interest in the mobile communication field. A new age has begun for telecommunication industry. Over the past decade wireless industry has grown at a remarkable pace, consequently level of technology development goes beyond the level of customer desire. Application flexibility and being highly dynamic will be the main features of beyond 3G services of interest to users. Being there all these emerging technologies in one cellular network has opened the work of designing and optimization of the networks to be viewed from a different perspective. APSEN analysis for Beyond 3G wireless networks has been discussed. “AP” stands for application layer, analysis of services and applications. “SE” stands for session layer, analysis of session management protocol and “N” for network layer, analysis for network protocols. The main purpose of our research is to focus on the challenges offered at APSEN for beyond 3G wireless network. There are a lot of research challenges in each of the different layers but focus will be on APSEN. The objective is to take a look at and familiarize with some of the major challenges offered at APSEN for beyond 3G wireless network. Qualitative approach has been used which will help us to collect wide range of information and enhance our knowledge by analyzing the perspectives of different researchers.
22

STRATEGIC MODIFICATIONS TO OPTIMIZE A CELL PENETRATING ANTIMICROBIAL PEPTIDE

Reena Blade (7289858) 31 January 2022 (has links)
<p>Pathogenic bacteria are evolving to drug resistant strains at alarming rates. The threat posed by drug resistant bacterial infections emphasize the need to establish new antimicrobial agents. Of immediate concern regarding the dangers of antibiotic resistance is the existence of intracellular bacteria, which find refuge from bactericidal devices by hiding within mammalian cells. Unfortunately, many therapeutics, such as vancomycin, do not possess membrane penetrating abilities to achieve efficacious eradication of bacteria at the subcellular level, allowing infections to persist. In an effort to target pathogens that thrive within mammalian cells, features of cell penetrating peptides (CPPs) and antimicrobial peptides (AMPs) were combined to develop a dual action antimicrobial CPP, cationic amphiphilic polyproline helices (CAPHs). CAPHs have proven to be an effective antimicrobial agent to combat an array of both Gram negative and Gram positive bacteria. </p> <p> </p> <p>Herein, to improve CAPHs activity, we have demonstrated how the incorporation of strategic modifications has resulted in increased cell uptake, alternative subcellular locations for CAPHs, and advanced antimicrobial potency. By simultaneously extending the helical length of CAPHs while incorporating different hydrophobic groups in place of the original isobutyl moiety that compose CAPHs we have created a <b>FL-P17-5R </b>series of peptides with five carbon aliphatic motifs: <b>Fl-P17-5B</b>, <b>Fl-P17-5C</b> and <b>Fl-P17-5L. </b>Through these modifications the peptides proved to be 2 to 5-fold more efficient in accumulating in macrophage cells than parent peptide Fl-P14LRR and where able to clear intracellular pathogenic bacteria, such as <i>Listeria</i>, from infected macrophages by 26 to 54%. </p> <p> </p> <p>In addition to making the <b>Fl-P17-5R</b> series of CAPHs to potentiate CAPHs activity, modifications to the cationic moiety of CAPHs were explored. By incorporating a new cationic monomer into the CAPHs sequence, a guanylated amino proline (GAP) residue, we produced <b>Fl-P14GAP</b>, a CAPHs peptide with an organized cationic charge display. This modification resulted in a 5-fold increase in cell uptake and a 2 to 16-fold decrease in minimum inhibitory concentration (MIC) values against strains of enteric and ESKAPE pathogens in comparison to Fl-P14LRR. <b>Fl-P14GAP</b> also executed superior clearance of intracellular pathogenic bacteria that resulted in the complete eradication of a drug resistant strain of <i>A. baumannii</i> from infected macrophage cells. Overall, our efforts with the <b>Fl-P17-5R</b> series of CAPHs and <b>Fl-P14GAP</b> have strengthened the therapeutic potential of CAPHs in the hopes of addressing the need for novel antibiotics with the propensity to eradicate intracellular pathogens.</p>
23

Plant Carnivory and the Evolution of Novelty in <i>Sarracenia alata</i>

Wheeler, Gregory Lawrence 07 November 2018 (has links)
No description available.
24

Biophysical Characterization of Cell-Penetrating Peptides for Cargo Delivery or Lipid-Sensing

Vinay K. Menon (15295864) 13 June 2023 (has links)
<p>Peptides, specifically cell-penetrating peptides (CPP), have become wonderful research tools due to their enhanced stability, solubility, and ease of synthesis. They have been used for a wide range of biomedical applications, from insecticides to biosensors and drug-delivery scaffolds. The work presented in this dissertation characterizes the biophysical properties of two different CPPs. The first is the cationic amphiphilic polyproline helix (CAPH) peptide, P14LRR. In addition to cell penetration, this CPP has demonstrated broad spectrum antibacterial properties. Fluorescence polarization (FP) and SEC-MALS were conducted to understand the dissociation constant (KD) and oligomerization effects of P14LRR with respect to its putative molecular target in Staphylococcus aureus (S. aureus). A biotinylated derivative of this peptide was also used as a drug-delivery scaffold to transport fluorescently conjugated streptavidin into mammalian cells. A second CPP, DAN13, was also developed as a biosensor for phosphoinositide lipids, specifically PI(4,5)P2. This was effected through careful calibration using stacked supported lipid bilayers (SSLB) in combination with total internal reflection fluorescence (TIRF) microscopy. This was then used to determine the absolute densities and spatial distribution of PIP2 in live KRas mutant cells.</p>
25

Habitat use and distribution of the loggerhead sea turtle (Caretta caretta) in the Mediterranean Sea: Implications for marine planning strategies

Abalo Morla, Sara 06 November 2023 (has links)
Tesis por compendio / [ES] Las tortugas bobas son organismos de gran movilidad que ocupan hábitats extensos y diversos, lo que las expone a varias amenazas que pueden afectar negativamente a la persistencia de sus poblaciones. Delinear medidas prioritarias de conservación para esta especie es todo un reto debido a la escasez del conocimiento integrado sobre su supervivencia, uso de hábitat y exposición relativa a amenazas, especialmente durante las primeras etapas de su ciclo vital. En la cuenca occidental del mar Mediterráneo esto adquiere mayor relevancia si se contextualiza en el proceso de colonización que está teniendo lugar en la zona durante la última década. Se ha registrado un aumento en el número de nidos y hembras nidificantes, para cuya protección se han tomado medidas de gestión como la reubicación de nidos y la inclusión de neonatos en programas de "head-starting". Esta coyuntura ha ofrecido una oportunidad única para incrementar el conocimiento sobre la supervivencia, dispersión y uso de hábitat de hembras nidificantes y post-neonatos de tortuga boba. Ninguna investigación previa ha realizado un seguimiento por satélite de hembras nidificantes en el Mediterráneo occidental, ni de post-neonatos mediterráneos con tamaño inferior a 35 cm. La finalidad de esta tesis es abordar las lagunas de conocimiento mencionadas y aportar herramientas para mejorar las estrategias de planificación marina dirigidas a la conservación de la tortuga boba en el Mediterráneo. Los principales objetivos fueron: i) proporcionar las primeras estimaciones empíricas de supervivencia de post-neonatos, ii) dilucidar las rutas de dispersión y el uso de hábitat en las diferentes etapas del ciclo vital, iii) identificar áreas relevantes para su protección, iv) evaluar la eficacia de las actuales áreas marinas protegidas (AMPs) para la conservación de la tortuga boba, y v) proponer medidas de conservación basadas en el análisis espacial. Para ello, se analizaron las trayectorias de 117 tortugas seguidas vía satélite entre 2003 y 2022. Estos datos incluyen las primeras trayectorias de hembras nidificantes en España y de post-neonatos mediterráneos, que se han publicado en un repositorio. Además, se realizó la primera evaluación del uso de hábitat y de AMPs por tortugas bobas marcadas en el Mediterráneo occidental, a lo largo de su ciclo vital. Los resultados de esta tesis muestran, por primera vez, la capacidad de supervivencia y dispersión, así como uso de hábitat de post-neonatos de tortuga boba en el Mediterráneo. Los mares Jónico y de Levante se identificaron como zonas potenciales de desarrollo de post-neonatos. Por otro lado, las hembras mostraron dos comportamientos diferentes durante el periodo de inter-anidación: i) fidelidad a la zona de nidificación, o ii) comportamiento exploratorio de nidificación. Durante la etapa no reproductora, la mayoría de las hembras permanecieron alimentándose en aguas oceánicas de la cuenca argelina. Además, se registró por primera vez la reemigración de esta especie para nidificar de nuevo en España, lo que confirma que las hembras pueden mostrar un cierto grado de fidelidad al lugar de nidificación entre ciclos reproductores. La presente tesis confirma la importancia de la cuenca argelina para las tortugas bobas del Mediterráneo occidental, en particular para los juveniles y adultos. Otras zonas identificadas como importantes son el sur del mar Balear, el mar de Alborán, el canal de Sicilia, el noreste de Túnez, las aguas de Malta, el mar Tirreno y el mar Jónico, según la etapa vital. El análisis de la distribución espacial de la tortuga boba también ha revelado que la distribución y cobertura actuales de las AMPs mediterráneas no contribuyen a alcanzar los objetivos de conservación para esta especie. Los resultados obtenidos en esta tesis contribuyen al conocimiento de la supervivencia y uso espacial de la tortuga boba a lo largo de su ciclo vital en el mar Mediterráneo. / [CA] Les tortugues babaues són organismes de gran mobilitat que ocupen hàbitats extensos i diversos, la qual cosa les exposa a diverses amenaces que poden afectar negativament la persistència de les seues poblacions. Delinear mesures prioritàries de conservació per a aquesta espècie és tot un repte degut a l'escassetat del coneixement integrat sobre la seua supervivència, ús d'hàbitat i exposició relativa a amenaces, especialment durant les primeres etapes del seu cicle vital. En la conca occidental de la mar Mediterrània això adquireix major rellevància si es contextualitza en el procés de colonització que està tenint lloc en la zona durant l'última dècada. S'ha registrat un augment en el nombre de nius i femelles nidificants, per a la protecció de les quals s'han pres mesures de gestió com la reubicació de nius i la inclusió de nounats en programes de "*head-*starting". Aquesta conjuntura ha oferit una oportunitat única per a incrementar el coneixement sobre la supervivència, dispersió i ús d'hàbitat de femelles nidificants i post-nounats de tortuga babaua. Cap investigació prèvia ha realitzat un seguiment per satèl·lit de femelles nidificants en el Mediterrani occidental, ni de post-nounats mediterranis amb grandària inferior a 35 cm. La finalitat d'aquesta tesi és abordar les llacunes de coneixement esmentades i aportar eines per a millorar les estratègies de planificació marina dirigides a la conservació de la tortuga babaua al Mediterrani. Els principals objectius van ser: i) proporcionar les primeres estimacions empíriques de supervivència de post-nounats, *ii) dilucidar les rutes de dispersió i l'ús d'hàbitat en les diferents etapes del cicle vital, *iii) identificar àrees rellevants per a la seua protecció, *iv) avaluar l'eficàcia de les actuals àrees marines protegides (*AMPs) per a la conservació de la tortuga babaua, i *v) proposar mesures de conservació basades en l'anàlisi espacial. Per a això, es van analitzar les trajectòries de 117 tortugues seguides via satèl·lit entre 2003 i 2022. Aquestes dades inclouen les primeres trajectòries de femelles nidificants a Espanya i de post-nounats mediterranis, que s'han publicat en un repositori. A més, es va realitzar la primera avaluació de l'ús d'hàbitat i de *AMPs per tortugues babaues marcades en el Mediterrani occidental, al llarg del seu cicle vital. Els resultats d'aquesta tesi mostren, per primera vegada, la capacitat de supervivència i dispersió, així com ús d'hàbitat de post-nounats de tortuga babaua al Mediterrani. Les mars Jònic i de Llevant es van identificar com a zones potencials de desenvolupament de post-nounats. D'altra banda, les femelles van mostrar dos comportaments diferents durant el període de *inter-implantació: i) fidelitat a la zona de nidificació, o *ii) comportament exploratori de nidificació. Durant l'etapa no reproductora, la majoria de les femelles van romandre alimentant-se en aigües oceàniques de la conca algeriana. A més, es va registrar per primera vegada la reemigració d'aquesta espècie per a nidificar de nou a Espanya, la qual cosa confirma que les femelles poden mostrar un cert grau de fidelitat al lloc de nidificació entre cicles reproductors. La present tesi confirma la importància de la conca algeriana per a les tortugues babaues del Mediterrani occidental, en particular per als juvenils i adults. Altres zones identificades com a importants són el sud de la mar Balear, la mar d'Alborán, el canal de Sicília, el nord-est de Tunísia, les aigües de Malta, la mar Tirrena i la mar Jònica, segons l'etapa vital. L'anàlisi de la distribució espacial de la tortuga babaua també ha revelat que la distribució i cobertura actuals de les *AMPs mediterrànies no contribueixen a aconseguir els objectius de conservació per a aquesta espècie. Els resultats obtinguts en aquesta tesi contribueixen al coneixement de la supervivència i ús espacial de la tortuga babaua al llarg del seu cicle vital en la mar Mediterrània. / [EN] Loggerhead sea turtles (Caretta caretta) are highly mobile organisms, which occupy diverse habitats that often span large distances, exposing them to threats that can negatively impact the ability of their populations to persist. Delineating conservation priority measures for this species is challenging since integrated knowledge on survival, habitat use and the relative exposure to threats remains scarce, especially during the early life stages. In the western Mediterranean basin this is particularly relevant when considering the current colonization process taking place in the area within the last decade. During recent years, records on nesting females and clutches have increased and, when possible, management measures such as nest relocation and head-starting programs have been undertaken. This offers a unique opportunity to fill in the knowledge gaps on survival, dispersal routes and habitat use of loggerhead nesting females and post-hatchlings. No research prior to this thesis has satellite-tracked nesting and post-nesting females in the western Mediterranean, nor Mediterranean post-hatchlings smaller than 35 cm. The present thesis aims to address the aforementioned knowledge gaps and enhance marine planning strategies for loggerhead conservation in the Mediterranean Sea. The main objectives were: i) to provide the first empirical survival estimates for head-started post-hatchlings, ii) to elucidate the dispersal routes and habitat use at different life stages, iii) to identify areas that should be considered for protection, iv) to assess the effectiveness of current marine protected areas (MPAs) and other protection measures for loggerhead conservation, and v) to propose spatial conservation measures based on research findings. To achieve these objectives, trajectories of 117 turtles satellite-tracked between 2003 and 2022 were analyzed. This dataset includes the first tracking data of nesting and post-nesting females in Spain and Mediterranean post-hatchlings, which have been made publicly available in a data repository. Moreover, the first assessment of habitat use and the use of MPAs for loggerhead sea turtles tracked from western Mediterranean thorough their life cycle was conducted. The outcomes of this thesis revealed, for the first time, the capability of survival and dispersal, as well as the habitat use of post-hatchlings in the Mediterranean Sea. The Ionian and Levant Seas were identified as potential developmental areas for post-hatchlings. Nesting females exhibited three different behaviours during the inter-nesting period: i) some degree of fidelity to a nesting area, ii) an exploratory nesting behavior, or iii) movement towards oceanic waters after tagging. In addition, the first-time remigration of this species to nest in Spain was recorded, confirming that females show some degree of nest site fidelity between breeding cycles. During the non-breeding stage, females remained in most cases foraging in oceanic waters of the Algerian basin. The present thesis has validated the significance of the Algerian basin for loggerhead sea turtles satellite-tracked from the western Mediterranean, particularly for juveniles and adults. In addition, other important areas inhabited by the loggerhead turtles were identified in the southern Balearic Sea, the Alboran Sea, the Sicilian Channel, the Northeast Tunisia, Maltese waters, the Tyrrhenian Sea and the Ionian Sea, depending on the life stage. The analysis of the spatial distribution of the loggerhead sea turtle has also revealed that the current distribution and coverage of Mediterranean MPAs are not effective in achieving this species' conservation goals. Outcomes from the present thesis significantly enhance our understanding of the survival and spatial use of the loggerhead sea turtle throughout its life cycle in the Mediterranean Sea. / I would like to express my gratitude to the Ministry of Education, Culture and Sports of Spain for the opportunity to develop this thesis under the predoctoral training grant [FPU15/01823], MEC, Spain. Satellite tagging conducted in the Valencia region was supported by the “Servicio de Vida Silvestre de la Generalitat Valenciana”. Additionally, I am thankful for the support received from the contracts: “Seguimiento mediante marcaje satelital de 10 crías de tortuga boba (Caretta caretta) nacidas en 2016 en el litoral valenciano" and "Marcaje satelital y seguimiento de hembras reproductoras de tortuga boba (Caretta caretta) ante episodios de anidación en las playas del Mediterráneo peninsular y Baleares en 2019", both contracts in the framework of the project "LIFE IP-PAF INTEMARES [LIFE15 IPE ES 012] "Gestión integrada, innovadora y participativa de la Red Natura 2000 en el medio marino español”, coordinated by the Biodiversity Foundation. Similarly, I would like to mention and thank the support received from the contract "Marcaje satelital y seguimiento de hembras reproductoras de tortuga boba (Caretta caretta) ante eventos de anidación en el litoral español" funded by the "Ministerio de Transición Ecológica y Reto Demográfico", Spain. The results of Chapter 6 "Marine protected areas and loggerhead turtles in the Mediterranean Sea" are also part of action C2.2 of the project LIFE IP INTEMARES. / Abalo Morla, S. (2023). Habitat use and distribution of the loggerhead sea turtle (Caretta caretta) in the Mediterranean Sea: Implications for marine planning strategies [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/199233 / Compendio

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