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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.
341

Design, synthesis and biomedical applications of Azabicycloalkanone Amino Acid Peptidomimetics

Atmuri, Nagavenkata 02 1900 (has links)
No description available.
342

UV Emitting Nanoscale Scintillators for Biomedical Applications

Espinoza Villalba, Sara 26 November 2019 (has links)
In the medical field, the applications of ultraviolet (UV) radiation are limited to skin or reachable sites due to its low penetration depth into biological tissue. Contrary to UV radiation, X-rays can penetrate the body with almost no attenuation, but they result in toxic side effects. Inorganic scintillators absorb X-rays and convert them into UV or visible photons and are usually used for medical imaging. We propose the use of high density inorganic nanoscale scintillators with the ability to absorb externally applied ionizing radiation directly at the site of application, e.g., inside a tumor, and to convert this ionizing radiation into UV photons in situ, enabling new biomedical applications inside the body. In this thesis, two specific new biomedical applications are discussed in detail: The first application is the use of UV-B emitting nanoscale scintillators for highly localized drugs released or activation of photoactivable therapeutics using only X-rays. The second novel approach is the use of UV-C emitting nanoscale scintillators as radiation sensitizers. However, size-reduction of inorganic scintillators, and most inorganic phosphors in general, usually result in quenching of the photoluminescence properties, defects on the surface of the particles, and a decrease of radiation hardness. Colloidal solutions of nearly monodisperse LaPO4:Gd nanocrystals (5nm) were shown to strongly emit UV radiation upon excitation with X-rays or vacuum UV radiation (160nm). The UV emission of the particles consisted mainly of a single line at 311nm. This UV-B emission of the particles was used to excite the fluorescence of laser dyes dissolved in the colloids. The emission of the dyes was also observed in the case of high dye concentrations, proving that the concept of using radiation with a high penetration depth (X-rays) to excite fluorescence emission with a low penetration depth (UV-B) wavelength is feasible. Pr-doped LuPO4 emits UV-C radiation between 225 and 280nm, where DNA shows strong absorption bands. Therefore, a systematic study of the luminescence of LuPO4:Pr was performed: Different doping concentrations, particle sizes, and excitation sources were compared. Furthermore, it was found that Pr and Nd co-doped LuPO4 results in increased UV-C emission independent of excitation source due to energy transfer. The highest UV-C emission intensity was observed for LuPO4:Pr,Nd(1%,2.5%) upon X-ray irradiation. Finally, LuPO4:Pr,Nd nanoparticles were synthesized, and the biological efficacy of the combined approach (X-rays and UV-C) was assessed using the colony formation assay. Cell culture experiments confirm increased cell death compared to X-rays alone due to the formation of UV-specific DNA damages, supporting the application of the herein synthesized particles as radiation sensitizers.
343

Reliable General Purpose Sentiment Analysis of the Public Twitter Stream

Haldenwang, Nils 27 September 2017 (has links)
General purpose Twitter sentiment analysis is a novel field that is closely related to traditional Twitter sentiment analysis but slightly differs in some key aspects. The main difference lies in the fact that the novel approach considers the unfiltered public Twitter stream while most of the previous approaches often applied various filtering steps which are not feasible for many applications. Another goal is to yield more reliable results by only classifying a tweet as positive or negative if it distinctly consists of the respective sentiment and mark the remaining messages as uncertain. Traditional approaches are often not that strict. Within the course of this thesis it could be verified that the novel approach differs significantly from the traditional approach. Moreover, the experimental results indicated that the archetypical approaches could be transferred to the new domain but the related domain data is consistently sub par when compared to high quality in-domain data. Finally, the viability of the best classification algorithm could be qualitatively verified in a real-world setting that was also developed within the course of this thesis.
344

Strukturelle und funktionelle Untersuchungen von Domänen des spannungsabhängigen Kaliumkanals Tsha3 aus der Regenbogenforelle Onchorhynchus Mykiss / Structural and functional analyses of domains of the Kv Tsha3

Herrling, Regina 20 June 2014 (has links)
Voltage gated potassium channels (Kv) play a key role in the nervous system- not only due to their involvement in the action potential. Vertebrates express four subtypes, which are termed Kv1, Kv2, Kv3 and Kv4, respectively. Tsha3 is a Kv1 channel which was originally isolated from brain tissue of rainbow trout (Oncorhynchus mykiss). This channel possesses an unique amino terminus and a characteristic amino acid sequence in the T1 domain, which is engaged in the oligomerization of Kv α-subunits and is thus involved into the segregation of subfamilies. The two major goals of this thesis were the structural and functional characterization of the N-terminal cytosolic domain of Tsha3 as well as the invention of a system to gain data about the functional dynamics of full length Kv channels. Molecular biological techniques were used to isolate mRNA from trout brains, to transcribe it into cDNA and clone it into vectors. DNA from such plasmids was ligated into expression vectors for heterologous expression in E. coli, P. pastoris and Sf21 cells, with concomitant fusion of marker proteins (GFP or DsRed) or tags (6 x HisTag or StrepTagII) due to the individual experiment. Protein was overexpressed in E. coli and affinity purified to analyze separated domains with biochemical (SDS-PAGE and Western Blot, Pull-Down-Assay or Dot-Blot-Assay) or biophysical (CD-spectroscopy, EPR spectroscopy) efforts. The P. pastoris system to express Tsha1 was established, to generate a system for future EPR-measurements of whole Kv channels. Heterologous expression of Kv1α (Tsha3 and Tsha1) and the core domain of Kvβ in Sf21 cells was performed to analyze the subcellular distribution of the respective subunits via fluorescence microscope and via subcellular fractionation of cell lysates with downstream biochemical analyses (SDS-PAGE and Western Blot). Furthermore the gating of diverse fusion constructs of Tsha3 in co-expressions and the gating of diverse cystein substitution mutants of Tsha1 were measured via path-clamp recordings in whole cell modus. The structural analyses of the N-terminal cytosolic domain (NCD) of Tsha3 revealed that the 128 amino acid containing part before the T1-domain (Tsha3-NT) can be structurally divided into three parts of different structure and mobility. The most outward part possesses a very high mobility and is putatively unfolded as random coil. This section is expected to express no tertiary contacts. The middle part of Tsha3-NT is structured in α-helices and β-sheets and thus slightly immobile. This folded part is also assumed to build no tertiary structure and to be exposed into the cytosol. The third, which is directly neighboring the T1 domain, has the most restricted mobility of Tsha3-NT. It consists predominantly of α-helices and exhibits a tertiary structure, putatively with the T1 domain. Tsha3-NCD self-tetramerizes and oligomerizes with Tsha1, although mutations exist in Tsha3 in conserved amino acids, which were reported to function in subfamily specific hetero-tetramerization. Thus it is proven, that Tsha3 takes part in the segregation into the Kv1 subfamily. Furthermore, Tsha3 interacts with the core domain of Kvβ2 although there are also mutations in the reported consensus sequence for interaction. Association of Kvβ2 in co-expression studies directs Tsha3-DsRed fusion constructs from internal vesicular structures into the cell membrane. But the fusion with DsRed is leading to a loss of function of Tsha3 which cannot be rescued by co-expression of the chaperone Kvβ2. But- without fusion of marker proteins- Tsha3 was identified as an outward rectifier in a cooperative Bachelor Thesis. These structural data lead to the assumption, that Tsha3-NT exhibits lateral interactions and especially the helical but mobile middle part of the N-terminus can play such a role. Due to the localization next to the membrane, interactions with membrane proteins- putatively with protein cascades are possible. Although Tsha3-NT contains no reported interaction domains for protein-protein interactions, follow-up experiments should be performed to shed light on this interesting question. Tsha1 C30S C31S C180S C224A C239S C389S C424S C476S is a complete cysteine free mutant, which was identified as a functional voltage-gated potassium channel. It was expressed in and purified from eukaryotic cells (P. pastoris) and therefore it can be assumed to be properly folded and modified. After a slight optimization of the features of expression, this system can be used to reconstitute Tsha1 channels into liposomes and use them for Freeze Quench EPR to gain structural information about a Kv1 channel in the open as well as in the closed state. This is the first report of the establishment of a full length Kv for studies of structure and functional dynamics experiments.
345

Mobile Systems Engineering – Ein gestaltungsorientierter Ansatz zur Entwicklung und Anwendung mobiler Informationssysteme für produktbegleitende Dienstleistungen

Niemöller, Christina 13 September 2017 (has links)
In Wissenschaft und Praxis herrscht Einigkeit über die Notwendigkeit der Unterstützung von Dienstleistungen durch mobile Informationssysteme (IS). Der primäre Untersuchungsgegenstand der vorliegenden Dissertation ist die Gestaltung eines mobilen IS zur Unterstützung produktbegleitender Dienstleistungen. Innovativ an der im Rahmen dieses Promotionsverfahrens entwickelten Lösung ist die Verwendung der neu auf dem Markt erschienenen Smart Glasses, die u. a. dadurch, dass sie freihändig bedient werden können, einen Mehrwert zur Unterstützung während der Dienstleistungserbringung bieten. Ziel der Arbeit ist die Entwicklung von Gestaltungswissen zum Design, zur Implementierung und zur Evaluation mobiler Informationssysteme. Die Bearbeitung der Zielsetzung beinhaltet (1) die multi-methodische Analyse zentraler Anforderungen an das IS in Form der zu deckenden Informationsbedarfe der Leistungserbringer und der zu implementierenden Anwendungsfälle. (2) Die fachlichen Anforderungen adressierend, wird das Design, die Implementierung und die Evaluation des mobilen Informationssystems selbst durchgeführt. Hierzu werden zusätzlich technische Funktionalitäten der Smart Glasses erfasst. (3) Aus der Analyse, dem Design und der Evaluation des mobilen Informationssystems wird anschließend methodisches Gestaltungswissen abgeleitet. (4) Abschließend erfolgt die Anwendung des Gestaltungswissens innerhalb weiterer Dienstleistungssektoren (Logistikdienstleistungen, Gesundheitsdienstleistungen). Hierbei werden ein Smart Glasses-basiertes IS für die Unterstützung von Logistikdienstleistungen und eine Smartphone-Applikation zur Unterstützung von Gesundheitsdienstleistungen für das Entwicklungsland Papua-Neuguinea konzipiert. Die vorliegende Dissertation leistet einen Beitrag zum Service Systems Engineering als Teildisziplin der Wirtschaftsinformatik. Sie füllt die Forschungslücke zu evidenzbasiertem Gestaltungswissen in der Disziplin, indem durch einen gestaltungsorientierten Ansatz sowohl mobile Informationssysteme selbst, als auch methodische Erkenntnisse generiert werden.
346

Framställning av dränerande bärlager från bergtäkt

Abu Sulaiman, Iyad, Ibrahim, Miran January 2023 (has links)
Bearing layers are used in road and building constructions as underlying soil layers to provide stability and support to the top layer that takes up the load. A normal bearing layer contains different amounts of materials such as stone, gravel, and filler. That mixture of materials contains a large amount of filler to give the product tightness and stability. Draining bearing layers usually contain less filler than ordinary bearing layers, because their purpose is to improve the drainage properties and reduce the risk of damage due to water collection.This thesis work took place at NCC's quarries in Sälgsjö and Hammarby. At NCC's rock quarry, there already is a standard bearing layer with a grain size of 0/32 and a filler content of approximately 4–5%. In this degree project, a production process has been created to obtain a drain bearing layer where the filler content is reduced to approximately 2–3%. The requirement for a draining carrier layer is 2–3% filler content and this requirement has been followed in this production process. The draining bearing layer has been produced based on a standard product with the same grain size.There are practical limitations in how the operations work and what capabilities are required. Moisture in the material has also been a limitation. In this project, work is done with freshly crushed material, which has a relatively low moisture content (1–2%). A vibration-free screen like the function of the harp has been designed and built. Then the standard product was run through the harp at different gradients and the new product was analyzed in the lab to see what filler content was achieved. A simulation test was performed using a FEM design program called Digiroad at Chalmers University of Technology in Gothenburg.The results demonstrate that the utilization of the developed models of harp screens reduces the proportion of filler in the material. Additionally, the conducted harp screen analyses confirm that the designed harp screens are effective in transforming a standard bearing layer into a draining bearing layer, which helps to prevent water accumulation under roads or buildings and thus reduces the risk of damage and problems. The efficient production process for producing draining bearing layers can be of great importance to ensure a sustainable and safe infrastructure.
347

Evaluation of a medium-sized enterprise’s performance by data analysis : Introducing innovative smart manufacturing perspectives

Joseph Anand, Emmanuel, Chica Zafra, Luis Carlos January 2019 (has links)
Small and medium-sized enterprises are highly limited on resources for the transformation into smart factories. Nytt AB, a new startup specialized in smart manufacturing solutions, is completely focused on taking down the barriers with a basic solution: implementing a machine vision system with the purpose to monitor the machines of the factories. The main aim of this thesis is to analyze the data collected from two different machines of a medium-sized factory by monitoring the color states of the stack lights.First of all, some topics are analyzed in order to get a better understanding and knowledge of the main topic of this thesis: smart manufacturing. Secondly, the methodology used during the project is explained. Thirdly, the product developed by Nytt AB is described to get a better understanding. Together with this, the companies where the product is implemented are described. The next step is the presentation of the results by analyzing the data according to these parameters:(i), the availability of the machines, (ii), critical machine tool analysis; (iii),machine idling time; (iv), disruption events; and finally, (v), information transfer. In the results, some graphs and discussions are presented. In the following chapter the conclusions are presented, which allow the analyzed company to improve its current state. Lastly, the relocation of the product into the critical machine, the implementation of new sensors to detect temperature and vibration values of the machines and the implementation of the module OpApp within the factories are suggestions presented as future work at the end of this report. / Små och medelstora företag har mycket begränsade resurser för omvandling till smarta fabriker. Nytt AB, ett nystartat företag inom smart tillverkning, är helt fokuserad på att ta bort hinder med en enkel lösning: implementering av ett kamerasystem för övervakning av maskiner i fabriker. Huvudsyftet med detta examensarbete är att analysera data som samlats in från två olika maskiner i en medelstor fabrik genom att övervaka färgändringar i deras ljuspelare. För det första analyseras några ämnesområden för att få en bättre förståelse och kunskap om huvudtemat i detta examensarbete: smart tillverkning. För det andra förklaras den metod som används under projektet. För det tredje beskrivs den produkt som utvecklats av Nytt AB för att få en bättre förståelse. Tillsammans med detta beskrivs de företag där produkten implementeras. Nästa steg är presentationen av resultatet genom att analysera data enligt följande parametrar:(i), maskinens tillgänglighet; (ii), kritisk verktygsmaskinanalys; (iii), maskinens tomgångstid; (iv), störningshändelser och slutligen; (v), informationsöverföring. I resultatet presenteras några grafer och diskussioner. Slutsatserna presenteras därefter. Dessa slutsatser gör att det analyserade företaget kan förbättra sitt nuvarande tillstånd. Som framtida arbete föreslås slutligen flytt av kamerasystemet till den kritiska maskinen, införande av nya sensorer för att övervaka temperaturer och vibrationsvärden för maskinerna och implementeringav modulen OpApp i fabriker.
348

Våld mot de yngsta barnen – vilka tecken uppvisar barnen och hur kan våldet förebyggas? : En kvalitativ intervjustudie / Child abuse – which signs do the youngest children express and how can the violence be prevented? : A qualitative interview study

Mikaelsson Pfeil, August January 2023 (has links)
De yngsta barnens våldsutsatthet är ett allvarligt folkhälsoproblem och socionomer har en särskilt betydelsefull roll i det preventiva arbetet. Därutöver föreligger det en kunskapslucka beträffande de yngsta barnens våldsutsatthet, både i det aktuella forskningsfältet och hos yrkesutövande socionomer. Syftet i denna masteruppsats var att undersöka vilka tecken på våldsutsatthet som socionomer uppfattar att de yngsta barnen uppvisar och vilka förbättringsområden de kan identifiera, inom socialtjänsten, avseende att upptäcka våld mot barn i åldern 0–6 år. Metoden för datainsamlingen var semistrukturerade intervjuer och urvalet utgjordes av sju socionomer från antingen en mottagnings- eller en utredningsenhet. Intervjuerna transkriberades och analyserades sedermera med en kvalitativ innehållsanalys och det resulterade i fem kategorier med två till fyra tillhörande underkategorier. Kategorierna Mer explicita tecken och Mer implicita tecken innehåller en variation av tecken på våld mot de yngsta barnen. Intressanta tecken som framkom i uppsatsen var beteendeförändringar, barns egna berättelser om våldsutsatthet och tecken i kombination med bristfälligt föräldrabeteende. Därutöver visade resultatet att de yngsta barnen ger uttryck för tillbakadraget och utagerande beteende när de utsatts för våld. Vidare resulterade analysen av socionomernas utsagor om identifierbara förbättringsområden i de tre kategorierna Utbildning, Metodutveckling och Arbetsförhållanden. Framstående resultat avseende dessa kategorier var att socionomer är i behov av mer adekvat utbildning och bättre arbetsvillkor samt att människors bristande förtroende för socialtjänstens försvårar socionomers arbete med våldsutsatta barn. Resultaten diskuteras i relation till tidigare forskning och teorier och utifrån ett folkhälsoperspektiv synliggörs det exempelvis att screening kan vara en potentiell nyckel i socionomers arbete med att förebygga våld mot barn. Förslag på framtida forskning innefattar bland annat att undersöka andra professionellas uppfattningar om vilka tecken på våldsutsatthet som de yngsta barnen uppvisar.
349

Cumulative Impacts of Stream Restoration on Watershed-Scale Flood Attenuation, Floodplain Inundation, and Nitrate Removal

Goodman, Lucas M. 01 1900 (has links)
Severe flooding and excess nutrient pollution, exacerbated by heightened anthropogenic pressures (e.g., climate change, urbanization, land use change, unsustainable agricultural practices), have been detrimental to riverine systems and their estuaries. The degradation of riverine systems can negatively impact human and environmental health, as well as local, regional, and even global economies. Floods provide beneficial ecosystem services (e.g., processing pollutants, transferring nutrients and sediment, supporting biodiversity), but they can also damage infrastructure and result in the loss of human life. Meanwhile, eutrophication can cause anoxic dead zones, harming aquatic ecosystems and public health. To address the issues facing riverine systems, focus has shifted to watershed-scale management plans. However, it can prove challenging to quantify the cumulative impacts of multiple stream restoration projects within a single watershed on flooding and nutrient removal. Previous studies have quantified the effects of stream restoration on flood attenuation. However, our first study fills a substantial knowledge gap by evaluating the impacts of different floodplain restoration practices, varied by location and length, on flood attenuation and floodplain inundation dynamics at the watershed scale during more frequent storm recurrence intervals (i.e., 2-year, 1-year, 0.5-year, and monthly). We created a 1D HEC-RAS model to simulate the effects of Stage 0 restoration within a 4th-order generic watershed based on the Chesapeake Bay watershed. By varying the percent river length restored and location, we found that Stage 0 restoration, especially in 2nd-order rivers, can be particularly effective at enhancing flood attenuation and floodplain inundation locally and farther downstream. We addressed the water quality component by using a random forest machine learning approach coupled with artificial neural networks to find trends and predict nitrate removal rates associated with spatial, temporal, hydrologic, and restoration features. Our results showed that hydrologic conditions were the most important variable for predicting actual nitrate removal rates. Overall, both studies demonstrate the importance of hydrologic connectivity for flood attenuation, channel-floodplain exchange, and nutrient processing. / Maryland Department of Natural Resources; National Fish and Wildlife Foundation through the U.S. Environmental Protection Agency’s Chesapeake Bay Program Office; Chesapeake Bay Trust / Master of Science / Severe flooding and nutrient pollution from sources such as urban and agricultural runoff have been detrimental to the health of rivers. The degradation of rivers can negatively impact human and environmental health, as well as local, regional, and even global economies. Floods can be both helpful, by providing water quality benefits and supporting wildlife, and harmful, causing damage and even loss of life. Excess nutrients, such as nitrogen, can create underwater zones void of life, with serious consequences for aquatic life and public health. To address the flooding and water quality issues facing rivers, focus has shifted to landscapelevel river network management plans. However, it can prove challenging to understand the impacts of multiple stream restoration projects within a larger river network on flooding and nutrient removal. We address the flooding component by using a model to simulate the effects of different floodplain restoration techniques on a medium-sized watershed that is generally based on streams that flow into the Chesapeake Bay. Our model simulated small, relatively frequent storm events that, on average, occur every two years to once a month. By varying restoration length and location, we found that restoration practices with lower streambanks can be particularly effective at slowing down floods, reducing their overall severity by allowing more water to access the floodplains. This was especially true when restoration occurred in smaller streams, and the effects were seen both locally and farther downstream. We address the water quality component by using a different model to find patterns and predict nutrient removal rates associated with different landscape, seasonal, storm event, and restoration features. Our results showed that the most important variable for predicting nutrient removal rates was whether a stream was experiencing normal flow or stormflow conditions. Overall, both studies demonstrate the importance of restoring rivers in a manner that encourages water to flow from the channel into the floodplains during smaller storm events, because this will reduce the severity of downstream flooding while simultaneously improving water quality.
350

Numerical modeling of moving carbonaceous particle conversion in hot environments / Numerische Modellierung der Konversion bewegter Kohlenstoffpartikel in heißen Umgebungen

Kestel, Matthias 24 June 2016 (has links) (PDF)
The design and optimization of entrained flow gasifiers is conducted more and more via computational fluid dynamics (CFD). A detailed resolution of single coal particles within such simulations is nowadays not possible due to computational limitations. Therefore the coal particle conversion is often represented by simple 0-D models. For an optimization of such 0-D models a precise understanding of the physical processes at the boundary layer and within the particle is necessary. In real gasifiers the particles experience Reynolds numbers up to 10000. However in the literature the conversion of coal particles is mainly regarded under quiescent conditions. Therefore an analysis of the conversion of single particles is needed. Thereto the computational fluid dynamics can be used. For the detailed analysis of single reacting particles under flow conditions a CFD model is presented. Practice-oriented parameters as well as features of the CFD model result from CFD simulations of a Siemens 200MWentrained flow gasifier. The CFD model is validated against an analytical model as well as two experimental data-sets taken from the literature. In all cases good agreement between the CFD and the analytics/experiments is shown. The numerical model is used to study single moving solid particles under combustion conditions. The analyzed parameters are namely the Reynolds number, the ambient temperature, the particle size, the operating pressure, the particle shape, the coal type and the composition of the gas. It is shown that for a wide range of the analyzed parameter range no complete flame exists around moving particles. This is in contrast to observations made by other authors for particles in quiescent atmospheres. For high operating pressures, low Reynolds numbers, large particle diameters and high ambient temperatures a flame exists in the wake of the particle. The impact of such a flame on the conversion of the particle is low. For high steam concentrations in the gas a flame appears, which interacts with the particle and influences its conversion. Furthermore the impact of the Stefan-flow on the boundary layer of the particle is studied. It is demonstrated that the Stefan-flow can reduce the drag coefficient and the Nusselt number for several orders of magnitude. On basis of the CFD results two new correlations are presented for the drag coefficient and the Nusselt number. The comparison between the correlations and the CFD shows a significant improvement of the new correlations in comparison to archived correlations. The CFD-model is further used to study moving single porous particles under gasifying conditions. Therefore a 2-D axis-symmetric system of non-touching tori as well as a complex 3-D geometry based on the an inverted settlement of monodisperse spheres is utilized. With these geometries the influence of the Reynolds number, the ambient temperature, the porosity, the intrinsic surface and the size of the radiating surface is analyzed. The studies show, that the influence of the flow on the particle conversion is moderate. In particular the impact of the flow on the intrinsic transport and conversion processes is mainly negligible. The size of the radiating surface has a similar impact on the conversion as the flow in the regarded parameter range. On basis of the CFD calculations two 0-D models for the combustion and gasification of moving particles are presented. These models can reproduce the results predicted by the CFD sufficiently for a wide parameter range.

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