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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.
241

Emissions of organic compounds from technosphere articles : Measurements and modeling of mass transfer from consumer goods and building materials to air and water

Holmgren, Tomas January 2013 (has links)
This thesis describes the development of a generic model for predicting the emissions of organic compounds from materials used in the manufacture of various goods and products. Many products contain organic substances that are not bound to the matrix formed by their constituent materials and are thus able to dissociate from the material and become transferred into the surrounding environment. A wide range of materials and products are used in modern societies, and many compounds deriving from these materials are regarded as emerging pollutants in both indoor and outdoor environments. The model uses three components to describe the transfer of compounds from materials to the surrounding environment: partitioning of the compound between the material and its surroundings based on linear free energy relationships, diffusion within the material based on the Piringer equation, and convective mass transfer in air or water based on an empirical flat surface model. The model’s predictive capacity was tested against three experimental case studies: emissions of plasticizers from vinyl flooring and triphenyl phosphate from LCD screens into the air, and leaching of organophosphates from concrete into water. The rates of emission from vinyl flooring were clearly affected by the number of layers comprising the material. Triphenyl phosphate was found in the front surface of all tested flat screens and its rates of emission were related to the nature of the screen and its operating temperature. The model accurately predicted emissions into the air and leaching from concrete into water once modified to include modules that describe dissolution from surfaces and diffusion in water-filled pores. The model was then used to investigate emissions on the national scale. It was found that the rates of emission from vinyl flooring are not changing over time, and that the total mass of emitted material is dependent on annual sales volumes and the expected life span of the vinyl flooring. Moreover, the additive used has a large effect on the emitted mass. Emissions from flat screen displays depend strongly on their operating temperatures: displays with high working temperatures that are active for extended periods of time produce more emissions. The model was also used to study the release of organophosphates from the concrete used to make a bridge, which depended on the flow of water under the bridge, the temperature, the porosity of the concrete, and the additive’s water solubility. Data on annual sales volumes and the total surface area of sold goods are essential when studying emissions on a national scale. National retailers’ organizations are valuable sources of such information. When adequate data are not available, it is necessary to perform uncertainty analyses to determine the impact of uncertainty in the modeling of different stages of the emissions process in different scenarios.
242

Protein sorting and cell surface polarity in yeast / Proteinsortierung und Zelloberflächenpolarität in Hefe

Proszynski, Tomasz 14 October 2005 (has links) (PDF)
The studies presented here were focused on the understanding of the principles for protein sorting from the Golgi to the cell surface. As a marker protein we used Fus1p, a type I plasma membrane protein that is O-glycosylated on the extracellular domain and plays a role in cell fusion during yeast mating. Additionally, we analyzed mechanisms responsible for asymmetric distribution of Fus1p in mating cells. We demonstrated that the glycans attached to the protein act as a sorting determinant for protein transport to the cell surface. In cells lacking PMT4, encoding a mannosyltransferase involved in the initial step of O-glycosylation, Fus1p was not glycosylated and accumulated in late Golgi structures. A similar defect in exocytosis was observed when a Fus1p mutant lacking the O-glycosylated domain was expressed in wild-type cells, however, the cell surface delivery could be rescued if the 33 amino acid portion of the Fus1p ectodomain, containing 15 potentially glycosylated sites was added to the protein. It was previously well documented in epithelial cells that different types of protein glycosylation and association with lipid rafts play a role of determinants for protein delivery to the apical plasma membrane. However, otherwise the machinery responsible for cargo sorting to the apical membrane is poorly understood. Our finding that also in yeast, protein glycosylation can function as a sorting determinant provides a new possibility to investigate underlying mechanisms...
243

Lipid rafts in protein sorting and yeast cell polarity

Klemm, Robin 18 July 2007 (has links) (PDF)
The major sorting station of biosynthetic material destined for the cell surface or secretion is the trans Golgi Network, TGN. This organelle sorts proteins and lipids into vesicular transport carriers that are targeted via different pathways to distinct membrane compartments of the cell. The molecular principles that operate in cargo sorting at the TGN are still not very well understood. Especially, we know very little about the sorting of lipids. It was postulated that a sorting mechanism based on clustering of lipid rafts, dynamic membrane domains enriched in sphingolipids and sterols, could be an important part of the picture. My thesis study dealt with the elucidation of the molecular sorting principles at the TGN and their exploitation for cell surface polarity in the yeast Saccharomyces cerevisiae. To this end, we conducted a genome wide screen that identified yeast mutants defective in cell surface delivery of the model cargo protein FusMid-GFP. The most striking result of this screen was that mutant strains with defects in ergosterol (the major yeast sterol) and sphingolipid biosynthesis lost sorting competence. To elucidate a direct role for sphingolipids and ergosterol in cargo sorting and secretion we sought to characterize the lipid composition of secretory vesicles. Hence, we established a vesicle purification protocol based on an immunoisolation strategy. Additionally, in collaboration with the group of A. Shevchenko, we developed a mass spectrometry methodology that allows the comprehensive and quantitative lipid analysis of subcellular organelles. Preliminary results corroborate our genetic evidence. The data show that the vesicles are enriched in sphingolipids and decreased in phosphatidylcholine indicating a role for raft clustering in cargo sorting at the TGN. The studies of cell polarity during yeast mating also unraveled a role for raft clustering. We could identify that the lipid bilayer at the tip of the mating projection was more ordered than at the plasma membrane enclosing the cell body and that this was dependent on sphingolipid synthesis. The results of my thesis suggest that in the yeast Saccharomyces cerevisiae fundamental cell biological processes such as cargo sorting and vesicle formation at the TGN as well as cell surface polarity during mating employ raft clustering mechanisms.
244

The p97 ATPase and the Drosophila Proteasome : Protein Unfolding and Regulation

Björk Grimberg, Kristian January 2010 (has links)
For all living systems, there is a requirement to recycle and regulate proteins. In eukaryotic organisms this is accomplished by the proteasome. The p97 ATPase is another highly conserved and essential complex present throughout the eukaryotic cell. In Paper I we utilized UFD fluorescent substrates to address the role of p97 and cofactors in soluble proteasome degradation. Results using RNAi and Drosophila p97 mutants propose p97 to function upstream of the proteasome on cytosolic proteasome targets as an important unfoldase together with its Ufd1/Npl4 cofactors. The results implicate p97 to be important for degradation of proteasome substrates lacking natural extended peptide regions. In Paper II we focused on identifying transcription factors essential for production of proteasomal subunits and associated proteins in Drosophila S2 cells. We utilized an RNA library targeting 993 known or candidate transcription factors and monitored RNAi depleted Drosophila S2 cells expressing the UFD reporter UbG76VGFP. We identified a range of potential candidates and focused on the bZIP transcription factor Cnc-C. RNAi and qrt-PCR experiments implicated Cnc-C to be involved in transcription of proteasomal subunits. In Paper III we applied our knowledge gained from Paper I about p97 dependent substrates and set up a high-throughput microscopy screening method to potentially find inhibitors specifically targeting the p97 proteasomal sub-pathway. Utilizing UFD substrates with and without C-terminal peptide tails we determined if compounds inhibited the core proteasomal machinery or the p97 pathway specifically. Through a primary and secondary round of screening we identified several new compounds inhibiting the ubiquitin-proteasome pathway though none from our initial screening had specificity for p97. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.
245

Universell Design - en användbarhetsutvärdering av MyTobii C-series Control

Pettersson, Anders January 2008 (has links)
<p>Universal Design is a well established methodology with the fundamental purpose of designing products to be usable for as wide audience as possible, without the need of special adjustment to suit the individual. In this essay, Universal Design has had a clear influence in both the process and the result. The choice to use Universal Design as methodology in this usability evaluation, has essentiallv to do with the target audience.</p><p>As a part of the design process of MyTobii C8 has Tobii Technology ask for a usability evaluation. MyTobii C8 is an 8" touch screen computer with a windows based operating system which will initiate the software MyTobii C-Series Control. MyTobii C-Series Control is the control panel for MyTobii C8, whose interfaces constitute the platform for various modificarion of the unit. The interface of MyTobii C-Series Control is also the interface being evaluated. Because of the target audience being persons with different motoric and cognitive disabilities and theirs assistances, it is of great important that the interface is suitable for as many people as possible. With user tests, designed and analyzed with the help of Universal Design, different usability problems has been  identified and solved. Among the usability problems encountered the most vital has been the size and placement of the interactive parts and the physical interaction with the unit.</p> / <p>Universell Design är en genomarbetad metodologi, framtagen i syfte att göra produkter användbara och anpassade för så bred publik som möjligt, utan att produkten måste anpassas för individens egna förmågor. I detta arbete har Universell Design haft en tydlig och grundläggande roll i genomförandet och resultatet. Valet att använda sig av Universell Design i denna användbarhetsutvärdering har framför allt med fallstudiens målgrupp att göra.</p><p>Som en del av utvecklingsprocessen av MyTobii C8 har Tobii Technology efterfrågas en användbarhetsutvärdering. MyTobii C8 är en åtta tums touch screen dator med Windows-baserat operativsystem som vid start kommer att initiera mjukvaran MyTobii C-Series Control. MyTobii C-Series Control är kontrollpanelen för MyTobii C8 vars gränssnitt utgör plattformen för diverse inställningar av enheten det är också detta gränssnitt användbarhetsutvärdetingen har gjorts på. Då målgruppen för MyTobii C-Series Control är personer med motoriska och kognitiva handikapp samt deras assistenter och närstående personer, är det av stor vikt att gränssnittet är anpassat för så bred publik som möjligt. Genom användartester utformade och analyserade med hjälp av Universell Design har användbarhetsproblem samt förslag på lösningar presenterats. Bland de användbarhetsproblemen som påträffats har det framför allt varit storleken, placeringen av de interaktiava delarna samt själv interaktionen med touch screen skärmen  som har vant väsentliga.</p>
246

Brian De Palma : une esthétique de la violence? / Brian De Palma : an aesthetic of violence ?

Bchir, Aroussia 24 October 2016 (has links)
Approche esthétique de l’œuvre cinématographique de Brian De Palma. La problématique s’articule entre esthétique du montage et violence de l’image. En premier lieu, le texte interroge le mode de découpage privilégié par Brian De Palma en soulignant l'importance du plan-séquence et du split screen. L'usage du plan-séquence est, notamment, rapporté à la question du défaut de vision, phénomène considéré comme central. Un second moment de cette thèse est consacré à l'étude des personnages. Des personnages anti-héros, marginaux. L'accent est particulièrement mis sur le corps féminin. Regard et voyeurisme revient à la question du découpage privilégié par Brian De Palma. Comment Brian De Palma utilise-t-il le regard pour accéder à la violence ? Qu’est-ce que regarder chez Brian De Palma ? Comment les éléments voyeuristes depalmiens se construisent-ils à partir du langage cinématographique ? Le cinéma de Brian De Palma s’annonce aussi savant et complexe, entre classicisme et modernisme. Comment Brian De Palma travaille-t-il l’œuvre hitchcockienne pour offrir une conception nouvelle ? Comment violenter l’image pour extraire son invisible ? / An esthetically pleasing approach to Brian De Palma's cinematographic work. The issue revolves around editing aesthetics and image violence. First, the text questions the cutting mode favored by Brian De Palme, stressing the importance of sequence-shot and split screen. The use of sequence-shot is in particular brought by the issue of lack of vision, a phenomenon considered as central. A second point of this thesis is devoted to the study of the characters. Anti-hero characters, drop outs. Emphasis is particularly placed on the female body. And voyeuristic gaze returns to the issue of cutting by Brian De Palma. How does Brian De Palma use eyes to see violence ? What is the meaning of « looking » to Brian De Palm a? How are De Palma's voyeuristic elements constructed from film language ? Brian De Palma's film also promises to be clever and complex, between classicism and modernism. How does Brian De Palma use Hitchcock's work in order to offer a new design? How assaulting the image to get its unseen part ?
247

Desenvolvimento de um sensor eletroquímico planar modificado com 1-2 Diaminobenzeno (DAB) para monitoração de nitrito por FIA-automatizada. / Development of a planar electrochemical sensor modified with 1-2 Diaminobenzene (DAB) for nitrite measuring by automatic FIA.

Fernando Luis de Almeida 11 September 2009 (has links)
A presente dissertação de mestrado tem o propósito de relatar o desenvolvimento de um sensor planar eletroquímico com três eletrodos para o monitoramento de nitrito e seus interferentes (ácido úrico, ácido ascórbico e paracetamol). Para tal, no procedimento experimental é descrito o desenvolvimento do aparato extracorpóreo (mini-bomba compressora, válvulas solenóides e cela de análise). Esse é acoplado a um sistema de Análise por Injeção em Fluxo Automatizada (do inglês, Flow-injection Analysis) FIA-automatizada. Este trabalho também descreve a fabricação dos sensores em substrato de alumina, o processo de limpeza padrão dos eletrodos, o processo de obtenção dos eletrodos de referência em HCl (0,1 mol L-1) e ativação eletroquímica da superfície do eletrodo de trabalho com H2SO4 (0,1 mol L-1). Em seguida, é mostrada a estabilização dos eletrodos de referência Ag/AgCl em solução salina contendo cloretos, o estudo da secagem dos eletrodos em temperatura ambiente com exposição à luz e a caracterização dos mesmos por três métodos distintos, a saber: i) teste de reversibilidade (corrente redox vs. potencial); ii) variação do potencial com o tempo (coeficiente de degradação termodinâmica) e iii) variação do potencial com a concentração de cloretos. Também, apresenta-se a caracterização da área efetiva exposta do eletrodo de medição (trabalho) e os resultados da deposição de 1-2 Diaminobenzeno (DAB) como polímero seletivo. Além disso, são apresentados os resultados e discussões dos pseudo-eletrodos (recoberto ou não com Náfion® 117). Um ponto relacionado, a histerese associada à irreversibilidade dos eletrodos de referência resultou da ordem de 40 mVAg/AgCl Náfion® 117. Os potencias termodinâmicos observados foram da ordem de 100 ± 6 mVAg/AgCl Náfion® 117 para pseudo-eletrodo de referência sem e com Náfion® 117. Depois, foi realizado um estudo criterioso dos potenciais de resposta ao nitrito e aos interferentes por meio da técnica de DPV (do inglês, Differencial Pulse Voltammetry). Para evitar degradação acelerada (corrosão) do polímero sobre o eletrodo de trabalho, optou-se por realizar as medições com potencial igual a 0,50 VAg/AgCl Náfion® 117. Nessa condição, apresenta-se a monitoração de nitrito por FIA-automatizada na faixa de concentração de 50 a 250 mol L-1. Os resultados para a medição de nitrito mostraram que o sensor planar eletroquímico amperométrico desenvolvido é promissor, pois esse apresentou ótimo desempenho de reprodutividade (99,66%), sensibilidade (90 microA mol-1 L mm-2), seletividade (0,32%), repetitividade (91,28%) e estabilidade (15 ± 0,3 pA). / In this Master of Science, it has been developed an electrochemical planar sensor defined with three electrodes for nitrite measuring and its interferents (uric acid, ascorbic acid and paracetamol). In the experimental procedure, it is shown the development of an extracorporis set up (mini-pump, solenoid valves and analysis cell) which is coupled to a system of Flow-injection Analysis (FIA). This work also describes the sensor fabrication using alumina substrates, the standard cleaning of the electrodes, the process to obtain Ag/AgCl reference electrodes in HCl (0.1 mol L-1) and electrochemical activation of the working-electrode surface with H2SO4 (0.1 mol L-1). Following, it is shown the study of drying for electrodes at room temperature with exposition to room light and their characterization using three different methods: i) reversibility test (redox current vs. potential); ii) variation of the potential with the time (thermodynamics degradation coefficient) and iii) variation of the potential with the chloride concentration. Also, it is presented the characterization of the effective exposed area of the working electrode and the results of the deposited 1-2 Diaminobenzene (DAB) is presented as a selective polymer. In addition, the results and discussions of the pseudo-reference (recovered or not with Nafion® 117) are presented. Related to irreversibility is the hysteresis associated to the reference electrodes which resulted in the order of 40 mVAg/AgCl Nafion® 117. The observed thermodynamic potentials were of (100 ± 6) mVAg/AgCl Nafion® 117 for pseudo-electrodes recovered with Nafion® 117. Later on, a careful study of the response to nitrite and to its interferents was performed by means of the DPV technique (Differential Pulse Voltammetry). In order to avoid accelerated degradation (corrosion) of the polymer, measurements were performed at a potential of 0,5 VAg/AgCl Nafion® 117. In this condition, nitrite was monitored using the automatized-FIA (Flow Injection Analysis) for concentration in the range of 50 to 250 mol L-1. The results have shown that the planar amperometric sensor for nitrite measuring is usefull since it was observed excellent performance related to reproducibility (99.66%), sensitivity (90 microA mol-1 L mm-2), selectivity (0.32%), repetibility (91.28%) and stability (15.0 ± 0.3 pA).
248

Obten??o e caracteriza??o de filmes SnO2 depositados em vidro borosilicato por silk-screen modificado: SnCl2.2H2O como precursor

Noronha, Jos? Fernando Valverde 24 August 2007 (has links)
Made available in DSpace on 2015-03-03T15:11:25Z (GMT). No. of bitstreams: 1 JoseFernandoVN.pdf: 1709074 bytes, checksum: 0af621e6374e339196c6c65ecb0f15bc (MD5) Previous issue date: 2007-08-24 / O presente trabalho tem como objetivo investigar as caracter?sticas de filmes de SnO2 depositados em substrato de vidro borosilicato por um processo de silk-screen modificado para obten??o de espessura fina compat?vel com a aplica??o em c?lulas solares policristalinas de baixo custo. O filme de SnO2 ? um dos mais apropriados para obten??o de vidro TCO (transparent conductive oxide) para uso em c?lulas solares devido a sua baixa resistividade el?trica e alta transmit?ncia, sendo quimicamente inerte, mecanicamente duro e tem resist?ncia a altas temperaturas, o que facilita ent?o a calcina??o das amostras entre 500? C a 550? C. Os filmes foram obtidos a partir de uma solu??o precursora b?sica, preparada pela dissolu??o de SnCl2.2H2O em Etanol (99,5 %). Foi realizado um planejamento fatorial 2(3-1) para analisar a influ?ncia dos par?metros concentra??o da solu??o precursora (CETN), temperatura de calcina??o (TC) e taxa de aquecimento (tX) na calcina??o, sendo a concentra??o CETN o par?metro que apresentou maior efeito sobre os par?metros de respostas investigados: espessura do filme (?), resistividade de superf?cie (?) e a transmit?ncia relativa (?). Foi poss?vel obter com a metodologia utilizada, filmes com espessuras da ordem de 1 Nm com resistividade de superf?cie de 10 / e transmit?ncia relativa entre 70 e 80 %.
249

Simulering av filtrerade skärmfärger

Andersson, Christian January 2005 (has links)
This report present a working model for simulation of what happens to colors displayed on screens when they are observed through optical filters. The results of the model can be used to visually, on one screen, simulate another screen with an applied optical filter. The model can also produce CIE color difference values for the simulated screen colors. The model is data driven and requires spectral measurements for at least the screen to be simulated and the physical filters that will be used. The model is divided into three separate modules or steps where each of the modules can be easily replaced by alternative implementations or solutions. Results from tests performed show that the model can be used for prototyping of optical filters even though the tests of the specific algorithms chosen show there is room for improvements in quality. There is nothing that indicates that future work with this model would not produce better quality in its results. / Denna rapport presenterar en fungerande modell för att optiskt simulera vad som händer med färger på bildskärmar då skärmarna betraktas genom optiska filter. Resultat från modellen består av information som kan användas för visuell simulering av en skärm med applicerat filter på en annan visande skärm. Förutom ren bilddata kan modellen även producera färgskillnadsvärden som kan härledas från CIE 1931 XYZ-koordinater. Modellen är datadriven och kräver initiala mätningar på minst den skärm som ska simuleras samt filter. Hela modellen är uppdelad i tre separata moduler eller steg där de olika delarna lätt kan bytas ut för alternativa algoritmer och lösningar. Resultat från undersökningar visar på att modellen går att använda för prototypning även om de, för arbetet specifikt, valda algoritmerna för de olika stegen i undersökningen visar på brister i kvalité. Det finns inget som visar att framtida arbete där andra algoritmer valts inte skulle kunna prestera ännu bättre resultat.
250

Universell Design - en användbarhetsutvärdering av MyTobii C-series Control

Pettersson, Anders January 2008 (has links)
Universal Design is a well established methodology with the fundamental purpose of designing products to be usable for as wide audience as possible, without the need of special adjustment to suit the individual. In this essay, Universal Design has had a clear influence in both the process and the result. The choice to use Universal Design as methodology in this usability evaluation, has essentiallv to do with the target audience. As a part of the design process of MyTobii C8 has Tobii Technology ask for a usability evaluation. MyTobii C8 is an 8" touch screen computer with a windows based operating system which will initiate the software MyTobii C-Series Control. MyTobii C-Series Control is the control panel for MyTobii C8, whose interfaces constitute the platform for various modificarion of the unit. The interface of MyTobii C-Series Control is also the interface being evaluated. Because of the target audience being persons with different motoric and cognitive disabilities and theirs assistances, it is of great important that the interface is suitable for as many people as possible. With user tests, designed and analyzed with the help of Universal Design, different usability problems has been  identified and solved. Among the usability problems encountered the most vital has been the size and placement of the interactive parts and the physical interaction with the unit. / Universell Design är en genomarbetad metodologi, framtagen i syfte att göra produkter användbara och anpassade för så bred publik som möjligt, utan att produkten måste anpassas för individens egna förmågor. I detta arbete har Universell Design haft en tydlig och grundläggande roll i genomförandet och resultatet. Valet att använda sig av Universell Design i denna användbarhetsutvärdering har framför allt med fallstudiens målgrupp att göra. Som en del av utvecklingsprocessen av MyTobii C8 har Tobii Technology efterfrågas en användbarhetsutvärdering. MyTobii C8 är en åtta tums touch screen dator med Windows-baserat operativsystem som vid start kommer att initiera mjukvaran MyTobii C-Series Control. MyTobii C-Series Control är kontrollpanelen för MyTobii C8 vars gränssnitt utgör plattformen för diverse inställningar av enheten det är också detta gränssnitt användbarhetsutvärdetingen har gjorts på. Då målgruppen för MyTobii C-Series Control är personer med motoriska och kognitiva handikapp samt deras assistenter och närstående personer, är det av stor vikt att gränssnittet är anpassat för så bred publik som möjligt. Genom användartester utformade och analyserade med hjälp av Universell Design har användbarhetsproblem samt förslag på lösningar presenterats. Bland de användbarhetsproblemen som påträffats har det framför allt varit storleken, placeringen av de interaktiava delarna samt själv interaktionen med touch screen skärmen  som har vant väsentliga.

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