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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.
201

Development of a screening assay for inhibitors of inflammation useful against pancreatic cancer

Ghafoory, Shima January 2009 (has links)
Pancreatic cancer is the fourth most lethal cancer and ranks as the eighth most commonly diagnosed cancer worldwide. This is due to its rapid proliferation, strong metastatic potential and its delayed detection. One major risk factor for developing pancreatic cancer is the aggressive inflammatory disease chronic pancreatitis. Chronic inflammation frequently precedes the development of certain pancreatic cancers. Inflammation is a protective and necessary process by which the body can alert the immune system of the existence of a wound or infection and mount an immune response to remove the harmful stimuli and start wound healing. The cross-talking of cells of the immune system and infected cells happens through cytokines, soluble proteins that activate and recruit other immune cells to increase the system’s response to the pathogen. Failure to resolve the injury can result in persistent cytokine production that in turn allows a cell that is damaged or altered to survive when in normal conditions it would be killed. Inflammation is thought to create a microenvironment that facilitates the initiation and/or growth of pancreatic cancer cells. Cytokines use two important kinases for their signaling: Janus Kinases (JAKs) and Signal Transducers and Activators of Transcription (STATs). The JAKs are activated upon the binding of cytokines to their corresponding receptors. When activated, the JAKs activate STATs through tyrosine phosphorylation. The STATs transduce signals to the nucleus of the cells to induce expression of critical genes essential in normal physiological cellular events such as differentiation, proliferation, cell survival, apoptosis and angiogenesis. STAT3 (a member of the STAT family) is constitutively activated in some pancreatic cancers, promoting cell cycle progression, cellular transformations and preventing apoptosis. Therefore, STAT3 is a promising target for cancer treatment. Novel therapies that inhibit STAT3 activity in cancers are urgently needed. Natural products are a very good resource for the discovery of new drugs against pancreatic cancer. Covering more than 70% of the Earths surface, The Ocean is an excellent source of bioactive natural products. Harbor Branch Oceanographic Institute’s Center for Marine Biomedical and Biotechnology Research (HBOI-CMBBR) situated in Florida, aims to find new marine natural products useful in disease prevention and drug therapy. Their current focus is to look for novel treatments for preventing both the formation of new pancreatic tumors and the metastasis of existing tumors. The hypothesis of this degree project was that novel inhibitors of STAT3 useful in the treatment of pancreatitis and/or pancreatic cancer could be found from marine-natural products. The first specific aim of this degree project was to set up an assay to identify bioactive marine natural products as inhibitors of inflammation. Furthermore the assay was validated using a commercially available inhibitor of inflammation (Cucurbitacin I). The last aim was to further validate the assay by screening pure compounds and peak library material from the HBOI marine specimen collection. At the end of the experimentation time, the assay still was not set-up as there were difficulties in proper cell culture techniques and the cell line did not respond as advertised. While the results were not as expected, the work performed resulted in familiarization with research laboratory practices and increased laboratory skills. Moreover, the results from the assays point to future directions to accomplish this project. / Development of a screening assay for inhibitors of inflammation useful against pancreatic cancer
202

Formulation and characterization of W/O nano-dispersions for bioactive delivery applications

Chatzidaki, Maria D. January 2016 (has links)
The main objective of this study was the formulation of food-grade water-in-oil (W/O) nano-dispersions based mainly on medium or long-chain triglycerides. Two types of dispersions were formulated and structurally compared, namely emulsions and microemulsions. The systems were used as matrices for encapsulating targeted bioactive molecules with specific characteristics such as antioxidants or peptides. The structural characterization of the formulated systems was investigated using techniques such as Electron Paramagnetic Resonance (EPR) spectroscopy, Dynamic Light Scattering (DLS), Cryogenic Transmission Electron Microscopy (Cryo-TEM) and Small Angle Xray Scattering (SAXS). The existence of swollen inverse micelles was revealed for the case of microemulsions whereas larger droplets still at the nano-scale were observed for the case of emulsions. Structural differences in the presence of the bioactive molecules or induced by the alteration of components were also observed. In order to study the efficacy of the formulations, the proposed loaded systems were assessed either using EPR spectroscopy or Well Diffusion Assay (WDA) depending on the bioactive molecule. It was found that the encapsulated molecules retained their claimed characteristics when encapsulated to the proposed matrices. Finally, some of the formulated dispersions were investigated for their behavior under gastrointestinal (GI) conditions. A two-step digestion model using recombinant Dog Gastric Lipase (rDGL) and Porcine Pancreatic Lipase (PPL) was proposed to simulate lipid hydrolysis in humans. The studies revealed significant decrease of the rDGL specific activity in the presence of the microemulsion while in the presence of lower percent of surfactants (case of emulsion) no alterations were observed.
203

Self-determination as perceived by users in support services pursuant to LSS : An analysis on a municipal level

Rombo, Amanda January 2020 (has links)
Each year in Sweden, users in support services are invited to participate in a user survey investigating their perceived quality of care. Results of this survey on a municipal level have never been analysed. Therefore, the aim of this thesis was to use survey results from 2019 to investigate differences between support services pursuant to the Swedish Act concerning Support and Service for Persons with Certain Functional Impairments (LSS): daily activity, service home and group home. Furthermore, Self Determination Theory was used to consider the potential associations between the results of the user survey and the three basic psychological needs for self-determined behavior within the theory: autonomy, competence, and relatedness. In addition, user-staff communication was analysed. For examining differences, Welch’s ANOVAs were performed. Comparisons between the support services were made for seven questions from the user survey. Results showed significant differences between the support services for all questions included. Post hoc-analyses revealed that daily activity differed significantly from service home and group home for all questions and had the higher mean for all but one question. Significant differences between service home and group home were found for two questions. These findings indicate that there is still work left to be done for increasing the self-determination of users in different support services on a municipal level. Potential reasons for these differences were discussed. Furthermore, it was concluded that Self-determination theory provided a useful framework for analyses of user experiences of self-determination as associated to the user survey questions.
204

Antiviral Immune Responses to Invertebrate Iridescent Virus 6 in Drosophila

West, Cara C. 02 January 2018 (has links)
The innate immune system is a critical first line of defense against invading pathogens. Innate immunity directly detects pathogens, sets up an appropriate adaptive response, and can directly kill pathogens. Drosophila may lack an adaptive immune response, but have a robust innate immune system with a variety of defense effector mechanisms. While the responses to bacteria, fungi, and RNA viruses have been well characterized, not much is known about the response to DNA viruses. My studies have set out to characterize the Drosophila immune response to a DNA virus, utilizing the large dsDNA virus, Invertebrate Iridescent Virus 6 (IIV-6). IIV-6 infection causes shortened lifespan, and in later stages of infection, flies present with abdominal swelling and iridescent blue color. Our objectives were to identify pathways flies use to protect themselves from IIV-6 infection, determine how this protection is mediated, and to identify any immune inhibitors that IIV-6 uses to suppress innate immune signaling. I have found that IIV-6 strongly up-regulates a class of stress proteins with unknown function, termed Turandots, after infection in vivo or in vitro. This induction is dependent upon viral replication, requires JAK-STAT activation, and activation of p38b MAPK. In addition, the unpaireds, which function as JAK-STAT ligands, are upregulated after IIV-6 infection in a p38b-dependent manner. Together, this data suggests that p38b activation leads to production of unpaired cytokines and activation of JAK-STAT signaling to induce Turandots. I have also found that IIV-6 infected cells secrete protective factors. This response is induced within 12 hours of IIV-6 infection, exosome-mediated, and provides robust protection to naive cells challenged with an mCherry-expressing strain of IIV-6. Additionally, IIV-6 inhibits two major immune responses in Drosophila, the IMD and Toll pathways. Stimulation of IIV-6 infected Drosophila S2* cells with either IMD or Toll stimulators results in very poor antimicrobial peptide responses. Yet, IMD and Relish are still cleaved upon stimulation in IIV-6 infected cells, indicating that the block is downstream. In support of this finding, IIV-6 infected flies respond very poorly to infection with the enterobacteria Erwinia carotovora carotovora compared to mock-injected flies.
205

Финансирование социально-ориентированных государственных программ на региональном уровне РФ: проблемы и перспективы развития : магистерская диссертация / Financing of socially-oriented state programs at the regional level of the Russian Federation: problems and prospects of development

Часова, Ю. С., Chasova, Y. S. January 2022 (has links)
Структура магистерской диссертации включает в себя введение, три главы, заключение, список использованных источников и приложения. В первой главе рассмотрены теоретические основы программно-целевого метода, а также дополнена и обобщена классификация государственных программ. Во второй главе проанализировано социально-экономическое состояние Свердловской области, а также проведен анализ финансирования социально-ориентированных государственных программ. В третьей главе разработана методика оценки рисков при планировании и реализации государственной программы. В заключении сформированы основные выводы. / The structure of the master's thesis includes an introduction, three chapters, conclusion, list of references and appendices. The first Chapter discusses the theoretical foundations of the program-target method are considered, as well as the classification of state programs is supplemented and generalized. In the second Chapter analyzes the socially-economic state of the Sverdlovsk region, as well as analyzes the financing of socially-oriented state programs. In the third Chapter, the methodology of risk assessment in the planning and implementation of the state program is developed. In conclusion, the main conclusions are formed.
206

Position och perspektiv : En analys av kommunala tjänstemäns uppfattningar om statlig och kommunal styrning / Position and perspective : An analysis of municipal officials' perceptions of state and municipal governance

Solum-Faeste, William, Åkesson, John January 2024 (has links)
Människans krav på att själv få bestämma över sina intressen och angelägenheter har gamla anor. Kampen mellan centralmakt och lokalmakt går att finna redan under medeltiden. För att den tveeggade relationen mellan politik och offentlig förvaltning ska fungera väl så är det av essentiell betydelse att dessa demokratiska organ i stor utsträckning verkar i symbios. Detta ställer inte bara kompetenskrav på de tjänstemän som utgör den offentliga förvaltningen. Det är likaså av essentiell betydelse att samarbetet mellan styrande organ och verkställande organ kan kommunicera väl, samt fattar rättssäkra och demokratiska beslut innan de förankras i befolkningen. Oavsett innebär den dikotomiska uppdelningen mellan politik och förvaltning ett stort ansvar för de som ska förvalta politikens förtroende, och ett stort ansvar gällande medborgarnas förtroende och offentlig legitimitet. I denna studie granskas hur tjänstemän på kommunal nivå uppfattar statlig styrning och kommunal styrning. Idéen är sprungen ur tidigare forskning som påvisar att kommunala tjänstemän tycker att de besitter bäst förmåga att tolka och implementera politiska beslut i jämförelse med kommunen. De tycker också i större utsträckning att staten besitter högre grad av legitimitet att styra i jämförelse med den egna kommunen med hänvisning till professionalism och kompetens. Vad den tidigare forskningen dock inte fokuserar på är vilka värden som ligger till grund för tjänstemännens uppfattningar, varpå denna studie syftar till att expandera förståelsen och kunskapen inom detta vetenskapliga fält. Studien använder sig av kvalitativ metod genom intervjuer för att kartlägga vilken form av styrning som de tillfrågade tjänstemännen föredrar samt vilka värden som ligger till grund för deras lojalitet. Studiens resultat visar att ju närmare den lokalpolitiska maktens kärna som de tillfrågade tjänstemännen befinner sig, desto större är benägenheten att föredra kommunal styrning. De tillfrågade tjänstemännen som verkade längre ifrån den lokalpolitiska maktens kärna, det vill säga de tjänstemän som verkade närmare medborgarna, var mer benägna att föredra statlig styrning. Författarna till denna uppsats har från start haft som mål att bidra med kunskap inom ett vetenskapligt område som till stor del är outforskat. Vi hoppas att denna studie har nyanserat perspektiv på politisk styrning och hur förvaltningshierarkin kan påverka de offentliga tjänstemännens uppfattningar beroende på deras position, befogenheter och handlingsutrymme inom ramen för deras profession.
207

Onkogenomische Aspekte Zytokin-assoziierter Signaltransduktion / Oncogenomic aspects of cytokine-associated signal transduction

Schoof, Nils 21 October 2008 (has links)
No description available.
208

Systematic inference of regulatory networks that drive cytokine-stimulus integration by T cells

Pellet, Elsa Marie 03 January 2020 (has links)
Differenzierungsentscheidungen von Zellen werden durch die Integration mehrerer Stimuli bestimmt. Die Differenzierung von Helfer-T-Zellen (Th-Zellen) ist hierfür ein gut untersuchtes Beispiel: reife Th-Zellen entwickeln sich beim Kontakt mit einem für sie spezifischen Antigen zu einem spezialisierten Subtyp, der von den in ihrer Umgebung vorhandenen Zytokinen abhängt und exprimieren dann einen spezifischen Mastertranskriptionsfaktor. Die häufigsten Th-Zell-Subtypen sind T-bet-exprimierende Th1-Zellen und GATA-3-exprimierende Th2-Zellen. Neuere Entdeckungen bezüglich der Plastizität von Th-Zell-Subtypen sowie die Existenz von T-bet+GATA-3+ Hybrid-Phänotypen haben die detaillierte Untersuchung vom Differenzierungsprozessen von Th-Zellen mit komplexer Zytokinsignale motiviert. Dazu haben wir systematisch die Zytokine IFN-g, IL-12 und IL-4 während der primären Differenzierung Th-Zellen titriert und Signaltransduktion und Zielgenexpression quantifiziert. Der Umfang und die Komplexität der Daten machten eine systematische Analyse notwendig, um involvierte Mechanismen genau zu identifizieren. Lineare Regressionsanalyse wurde verwendet, um die Netzwerktopologie zu extrahieren, wobei schon bekannte und zahlreiche neue Interaktionen vorausgesagt wurden. Die prognostizierte Netzwerktopologie wurde dann verwendet, um ein mechanistisches, mathematisches Modell der Zytokinsignalintegration zu entwickeln. Diese Methode hat ein hochgradig vernetztes regulatorisches Netzwerk inferiert. Bisher nicht beschriebene Funktionen von STAT-Proteine, die die Neuverkabelung des Netzwerkes während der Differenzierung vermitteln, wurden vorhergesagt. Ausgewählte neue Interaktionen wurden in gezielten genetischen Experimenten bestätigt. Während gegenseitige Inhibitionsmotive oft als kanonische digitale Schalter interpretiert werden, funktioniert das Th-Zell-Netwerk als ein Rheostat, der Variationen der Zytokinsignale in graduelle Expressionsänderungen der Mastertranskriptionsfaktoren übersetzt. Unsere Arbeit erklärt mechanistisch das beobachtete Kontinuum von Th-Zelldifferenzierungszuständen entlang der Th1-Th2-Achse und beschreibt eine quantitative Methode für die datenbasierte Inferenz zellulärer Netzwerke der Signalintegration. / Cell-fate decisions are governed by the integration of multiple stimuli. Th cell differentiation is a well-studied example thereof: mature Th cells differentiate into a specialised subtype upon encounter with their cognate antigen depending on the polarising cytokines present in their environment and start expressing specific master transcription factors. The most common Th cell subtypes are T-bet-expressing Th1 cells and GATA-3-expressing Th2 cells. Recent discoveries concerning the plasticity of Th cell subtypes as well as the existence of stable T-bet+GATA-3+ hybrid Th1/2 phenotypes have stimulated the detailed study of the differentiation process under different assumptions than the hitherto valid paradigm of single master transcription factor expression by using complex cytokine signals as inputs. Here, we developed a data-based approach for inferring the molecular network underlying the differentiation of T-bet- and/or GATA-3 expressing lymphocytes. We performed systematic titrations of the polarising cytokines IFN-g, IL-12 and IL-4 during primary differentiation of Th cells and quantified signal transduction as well as target-gene expression. The size and complexity of the dataset made a systematic analysis necessary to identify the mechanisms involved. To extract the network topology, we used linear regression analysis, retrieving known regulatory mechanisms and predicting numerous novel ones. This network topology was used to develop a mechanistic mathematical model of cytokine signal integration. This approach inferred a highly connected regulatory network. Previously undescribed functions of STAT proteins mediating network rewiring during differentiation were predicted. Selected new interactions were confirmed by experiments using gene-deficient cells. Importantly, while mutual-inhibition motifs are often considered canonical digital switches, the inferred Th-cell network acts as a rheostat, generating a continuum of differentiated states along the Th1-Th2 axis. This work explains the observed Th1-Th2 cell fate continuum mechanistically and provides a quantitative framework for the data-based inference of cellular signal integration networks.
209

Étude des transitions de Peierls dans les systèmes unidimensionnels et quasi-unidimensionnels

Bakrim, Hassan January 2010 (has links)
We studied the structural instabilities of one-dimensional (1D) and quasi-one-dimensional (Q1D) electron-phonon systems at low temperature through two models, SuSchrieffer-Heeger (SSH) and molecular crystal (CM) with and without spin. The phase diagrams are obtained using a Kadanoff-Wilson renormalization group approach (GR). For the 1D half-filled system the study of the frequency dependence of the electronic gap allowed us to connect continuously the two limits, adiabatic and non-adiabatic. The Peierls and Cooper channels interference and the quantum fluctuations reduce the gap. A regime change occurs when the frequency becomes of the order of mean field gap, marking a quantum-classical crossover that is the Kosterlitz-Thouless type. At this level, the effective coupling behaves in power law function on frequency. For the case with spin, a gapped Peierls state is maintained in the non-adiabatic limit, while for the case without spin, the system transits to ungapped disordered state, namely the Luttinger liquid stat (LL). For the SSH model without spin, the GR confirms the existence of a threshold phonon coupling beyond which the gap is restored. The study of the rigidities of the two models without spin allowed us to trace the main features of the LL state predicted by the bosonization method. The study of the Holstein-Hubbard model has allowed us not only to reproduce the phase diagrams already obtained by the Monte Carlo method, but to highlight two additional phases, namely, free fermions phase and the bond charge-density-wave phase. We have extended this study to the quarter-filled Q1D Peierls systems at finite temperature. Within the SSH model, an unconventional superconducting phase with spin singlet symmetry SS-s emerges at low temperature when the deviation to the perfect nesting of the Fermi surface is strong enough. Peierls-SS transition is characterized by the presence of a quantum critical point at low frequency and by a power law behavior of the transition temperature as a function of frequency with an exponent identical to one of 1D system. This exponent which universality has been verified contrasts with the BCS result. Coulomb interactions have been introduced through the study of the extended SSH-Hubbard model. The extension of this work to half-filled SSH and CM cases was also performed.
210

Accurate Methodology for Monitoring Biomembrane Events

Winschel, Christine A. 26 July 2012 (has links)
Abstract ACCURATE METHODOLOGY FOR MONITORING BIOMEMBRANE EVENTS By Christine A. Winschel, Ph.D. A Dissertation submitted in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Chemistry at Virginia Commonwealth University. Virginia Commonwealth University, 2012 Major Director: Dr. Vladimir A. Sidorov ASSOCIATE PROFESSOR, DEPARTMENT OF CHEMISTRY This study describes the synthesis and characterization of a new receptor (cyclen 1) capable of strong selective binding of pyrene-based anionic dyes under near-physiological conditions. This receptor comprises four naphthylthiourea groups tethered to a cyclen core via an ester linkage. The most important finding was the ability of cyclen 1 to bind efficiently to a pH-sensitive pyranine dye, a dye that is commonly used in various biomembrane assays. The high affinity of cyclen 1 to pyranine, its impermeability to the lipid bilayer membrane, fast kinetics of binding, and ability to quench pyranine’s fluorescence were used as a basis for a new membrane leakage assay. This membrane leakage assay is fully compatible with the commonly applied pH-stat transport assay, and therefore it allows for differentiation of ion transport and nonselective leakage mechanisms within a single set of experiments. In the second part of this study a new methodology for the detection of lipid flip was developed. This methodology relies on the quenching of the fluorescence of a newly synthesized cascade-blue-labeled lipid through complex formation with cyclen 1. This receptor-dye complexation also has high affinity for binding at micromolar concentrations and can be reversed by either competitive displacement of the lipid probe or by enzymatic degradation of the receptor leading to the label release and fluorescence dequenching. This new methodology is suitable for the study of lipid flip in both model spherical bilayer membranes and in-vitro experiments, and is less invasive to the model and cell membranes than the commonly utilized 7-nitro-1,2,3-benzoxadiazol-4-yl (NBD)-dithionite methodology. Lastly, new pH-sensitive lipids were synthesized and utilized in the formulation of liposomes suitable for controlled drug release. These liposomes contain various amounts of internal NaCl and undergo internal acidification upon the exogenous addition of an HCl co-transporter in a physiologically relevant NaCl solution. Therefore, acidification ultimately leads to the hydrolysis of the pH-sensitive lipids and subsequent contents release. These liposomes were found to be insensitive to physiological concentrations of human serum albumin and to be non-toxic to cells at concentrations exceeding pharmacological relevance. These results render this new drug release model potentially suitable for in vivo applications.

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