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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.
1

The Presynaptic F-box Protein FSN-1 Regulates Synapse Development via Retrograde Insulin Signaling in Caenorhabditis elegans

Hwang, Christine 26 July 2010 (has links)
Synaptogenesis entails the development and establishment of functional synapses, which form the fundamental unit of communication in the nervous system. Initially identified in Caenorhabditis elegans (C. elegans), the FSN-1, F-box protein family has emerged as evolutionarily conserved binding partners of PHR family proteins, which regulate synaptogenesis. Previously, we have shown that FSN-1 and RPM-1 form a SCF/FSN-1/RPM-1 ubiquitin ligase complex that negatively regulates synapse growth by downregulating presynaptic targets, like the MAP kinase pathway. For my master’s thesis, I used a combination of both candidate and forward genetic approaches to identify additional components of signaling pathways that are regulated by FSN-1 during synaptogenesis. Our studies are among the first to suggest diverging roles for these partners and provide the first evidence for a mechanism through which the F-box protein regulates synaptogenesis via retrograde insulin/IGF/FOXO signaling and glucosaminidase/O-GlcNAc modifications.
2

The Presynaptic F-box Protein FSN-1 Regulates Synapse Development via Retrograde Insulin Signaling in Caenorhabditis elegans

Hwang, Christine 26 July 2010 (has links)
Synaptogenesis entails the development and establishment of functional synapses, which form the fundamental unit of communication in the nervous system. Initially identified in Caenorhabditis elegans (C. elegans), the FSN-1, F-box protein family has emerged as evolutionarily conserved binding partners of PHR family proteins, which regulate synaptogenesis. Previously, we have shown that FSN-1 and RPM-1 form a SCF/FSN-1/RPM-1 ubiquitin ligase complex that negatively regulates synapse growth by downregulating presynaptic targets, like the MAP kinase pathway. For my master’s thesis, I used a combination of both candidate and forward genetic approaches to identify additional components of signaling pathways that are regulated by FSN-1 during synaptogenesis. Our studies are among the first to suggest diverging roles for these partners and provide the first evidence for a mechanism through which the F-box protein regulates synaptogenesis via retrograde insulin/IGF/FOXO signaling and glucosaminidase/O-GlcNAc modifications.
3

Simulation-based fault propagation analysis of process industry using process variable interaction analysis

Hosseini, Amir Hossein 01 January 2013 (has links)
There are increasing safety concerns in chemical and petrochemical process industry. The huge explosion of Nowruz oil Field platform that happened in Persian gulf-IRAN at 1983, along with other disastrous events have effected chemical industrial renaissance and led to high demand to enhance safety. Oil and chemical Industries involve complex processes and handle hazardous materials that may potentially cause catastrophic consequences in terms of human losses, injuries, asset lost and environmental stresses. One main reason of such catastrophic events is the lack of effective control and monitoring approaches that are required to achieve successful fault diagnosis and accurate hazard identification. Currently, there are aggressive worldwide efforts to propose an effective, robust, and high accuracy fault propagation analysis and monitoring techniques to prevent undesired events at early stages prior to their occurrence. Among these requirements is the development of an intelligent and automated control and monitoring system to first diagnose faulty equipment and process variable deviations, and then identify hazards associated with faults and deviations. Research into safety and control issues become high priority in all aspects. To support these needs, predictive control and intelligent monitoring system is under study and development at the Energy Safety and Control Laboratory (ESCL) – University of Ontario Institute of Technology (UOIT). The purpose of this research is to present a real time fault propagation analysis method for chemical / petrochemical process industry through fault semantic network (FSN) using accurate process variable interactions (PV-PV interactions). The effectiveness, feasibility, and robustness of the proposed method are demonstrated on simulated data emanating from a well-known Tennessee Eastman (TE) chemical process. Unlike most existing probabilistic approaches, fault propagation analysis module classifies faults and identifies faulty equipment and deviations according to obtained data from the underlying processes. It is an expert system that identifies corresponding causes and consequences and links them together. FSN is an integrated framework that is used to link fault propagation scenarios qualitatively and quantitatively. Probability and fuzzy rules are used for reasoning causes and consequences and tuning FSN. / UOIT
4

The F-box Protein FSN-1 Governs Presynaptic Development in Caenorhabditis elegans

Watkins, Nicholas Arthur 25 August 2011 (has links)
Synapses are specialized sub-cellular junctions that transmit signals between neurons and their targets. In Caenorhabditis elegans (C. elegans) the F-box protein FSN-1 and the PHR family member RPM-1 form the SCFFSN-1 E3 ubiquitin ligase, which plays an important role in regulating synaptic growth factors. This SCF complex is evolutionarily conserved across species, and regulates many cellular processes including axon outgrowth, apoptosis and synaptogenesis. This thesis focuses on identifying targets of SCFFSN-1 that contribute to synaptogenesis. Forward genetics was employed to screens and isolate mutants that exhibit genetic interactions with fsn-1. I have identified an allele of the MAPK pmk-3(hp246) and three alleles of the MAPKKK dlk-1(hp180, hp192, hp195) that suppress fsn-1 defects. In addition, I have isolated five fsn-1 suppressing alleles and evidence suggests that these suppressors are likely novel fsn-1 suppressors.
5

The F-box Protein FSN-1 Governs Presynaptic Development in Caenorhabditis elegans

Watkins, Nicholas Arthur 25 August 2011 (has links)
Synapses are specialized sub-cellular junctions that transmit signals between neurons and their targets. In Caenorhabditis elegans (C. elegans) the F-box protein FSN-1 and the PHR family member RPM-1 form the SCFFSN-1 E3 ubiquitin ligase, which plays an important role in regulating synaptic growth factors. This SCF complex is evolutionarily conserved across species, and regulates many cellular processes including axon outgrowth, apoptosis and synaptogenesis. This thesis focuses on identifying targets of SCFFSN-1 that contribute to synaptogenesis. Forward genetics was employed to screens and isolate mutants that exhibit genetic interactions with fsn-1. I have identified an allele of the MAPK pmk-3(hp246) and three alleles of the MAPKKK dlk-1(hp180, hp192, hp195) that suppress fsn-1 defects. In addition, I have isolated five fsn-1 suppressing alleles and evidence suggests that these suppressors are likely novel fsn-1 suppressors.
6

Kategorisering av sortiment för ökad servicenivå : En fallstudie på Back on Track AB / Categorization of assortments for increased service level

Hammarström, Emilia, Hillberg, Elsa, Johnson, Staffan, Larsson, Adan January 2021 (has links)
Rapporten utgår från olika kategoriseringsmetoder för att på sikt öka servicenivån. Fallföretaget har under den senaste tiden expanderat, vilket bidragit till att de inte längre kan möta efterfrågan. De inköpsstrategier som tidigare använts är inte längre tillräckliga för de nya försäljningsvolymerna. Verksamheten har långa ledtider vilket ställt högre krav på inköpsstrategin och planering. Med hjälp av empiri, studentlitteratur, facklitteratur och observationer redogör rapporten för hur verksamheten kan förbättras genom en fallstudie. Med hjälp av observationer vid besöket hos fallföretaget kunde kartläggning av verksamheten och dess strategier slutföras, vilket ledde fram till rapportens syfte och frågeställningar. Genom att strukturera datan efter de olika metoderna, tillsammans med visuella hjälpmedel som diagram och grafer kunde resultatet gestaltas. Därefter analyserades resultatet för att dra slutsatser kring om det finns någon korrelation mellan teorin och rapportens resultat. Analysen lyfter fram hur kategorisering av metoderna används för att öka servicenivån. Därutöver analyseras för- och nackdelarna med de olika metoderna. Likaså behandlar rapporten vilken kategorisering som är mest lämplig i nuläget samt för framtiden. Det förekommer även diskussioner om olika prognosmodeller och hur man bör gå tillväga för att förbättra lagerstyrningen och höja servicenivån. Validiteten och reliabiliteten av rapporten diskuteras också för att kunna identifiera hur tillförlitlig rapporten är samt om den faktiskt mäter det den önskas mäta. Rapporten redogör för att FSN är den bästa kategoriseringen för fallföretaget. Genom att basera inköpen på prognosmodeller kan verksamheten hitta lämpliga orderkvantiteter. Den framtida inköpsstrategin baseras på kvantitativa modeller vilket bygger på historisk data. Utöver framtida inköpsstrategier föreslås hur verksamheten bör prioritera sina olika produkter för att på sikt höja servicenivån. Slutligen sammanfattas alla rekommendationer för en enklare förståelse av rapportens slutsats. / The report is based on various categorization methods that have been developed to increase the level of service in the long term. The case company has recently expanded, which has contributed to them no longer being able to meet the demand. The purchasing strategies they previously used are no longer sufficient for the new sales volumes. With long delivery times from factories in Asia, the intervals between stock refills are getting longer, which requires foresight. Using empirical data, student literature, non-fiction and observations, the report explains how the business can be improved through a case study. Calculations, formulas and tables are based on student literature and scientific articles. By starting from proven theories, the business's inventory management can be improved. With the help of observations during the visit to the case company, mapping of the business and its strategies could be completed, which led to the report's purpose and issues. By structuring the data according to the different methods, together with visual aids such as diagrams and graphs, the result could be shaped. The results were then analyzed to draw conclusions about whether there is any correlation between the theory and the report's results. The analysis highlights how categorization of the methods is used to increase the level of service. In addition, the advantages and disadvantages of the different methods are analyzed. Discussion about which categorization is most suitable in the current situation and for the future is then highlighted. There are also discussions about different forecast models and how to proceed to improve inventory management and raise the level of service. The validity and reliability of the report are also discussed in order to be able to identify how reliable the report is and whether it actually measures what it wishes to measure. The report states that FSN is the best categorization for the fall company. By analyzing forecast models based on demand from the categorization, a purchasing strategy for the company in the future is estimated. The future purchasing strategy is based on quantitative models, which is based on historical data that the case company currently lacks. In addition to future purchasing strategies, working methods with new products as well as improvement proposals with the work of categorization models are proposed. Finally, all recommendations are summarized for a simpler understanding of the report's discoveries.
7

Influência de defeitos nas propriedades mecânicas de juntas soldadas por FSW da liga AA6013-T6 / The influence of defects on the mechanical properties of friction stir welds in AA6013-T6

Marconato, Eduardo Amado 28 April 2009 (has links)
Made available in DSpace on 2016-06-02T19:12:15Z (GMT). No. of bitstreams: 1 3983.pdf: 5009328 bytes, checksum: 7a82aca5db5680e5fb627a9b54588309 (MD5) Previous issue date: 2009-04-28 / Financiadora de Estudos e Projetos / In 1991, it was developed a solid state welding process called Friction Stir Welding - FSW, intended to increase the number of applications for the aluminum and its alloys. As every welding process the presence of defects should be avoided to not compromise the quality of the welded joint. Some typical defects originating from FSW process are found in some joints depending of the welding parameters. Thus, this study has the purpose to evaluate the quality of welded joints in 3 mm thick 6013-T6 friction stir welded joints in function of the obtained defects, using different welding parameters. The characterization was based on metallography by OM and SEM of the welded joints in order to analyze the obtained defects. The mechanical properties were evaluated by tensile, microhardness and fatigue tests.Welds joints were intentionally produced to contain inner defects in the weld nugget like tunnel shaped along the joint and lack of root penetration of the welding tool. All welded conditions, the microhardness profiles show a big drop in hardness when crossing from the HAZ zone into the center of each weld, while the tensile and fatigue tests showed a strong defects influence in the mechanical properties. The lack of penetration weld defect had the worst results of mechanical properties compared to tunneling defects, and the sound weld joint exhibited the best results of mechanical properties for all conditions investigated. / Visando ampliar o número de aplicações para o alumínio e suas ligas, foi desenvolvido em 1991, um processo de soldagem no estado sólido denominado Friction Stir Welding. Como em todo processo de soldagem a presença de defeitos deve ser evitada, pois compromete a qualidade da junta soldada. Alguns defeitos típicos oriundos do processo FSW são encontrados em algumas juntas dependendo dos parâmetros de soldagem escolhidos. Assim sendo, este trabalho teve como principal objetivo estudar a influência de defeitos nas propriedades mecânicas de juntas soldadas pelo processo Friction Stir Welding da liga de alumínio 6013-T6, correlacionando as variações microestruturais obtidas com os diferentes parâmetros de soldagem adotados. Para tanto foram utilizados diferentes parâmetros de soldagem para a obtenção de juntas soldadas que apresentem defeitos distintos. A caracterização metalográfica se baseou em macrografias e micrografias via M.O. e MEV das juntas soldadas, de forma a analisar os defeitos obtidos. As propriedades mecânicas foram avaliadas por ensaios de tração, microdureza e fadiga. Foram obtidas soldas com defeitos internos a lente de soldagem em forma de vazios ao longo do cordão e soldas com falta de penetração na região da raiz. Em todas as condições foi observada uma redução brusca nos valores de microdureza na região da junta soldada, enquanto os ensaios de tração e fadiga revelaram forte influência da presença de defeitos na junta. A solda que apresentava como defeito a falta de penetração na raiz apresentou resultados de propriedades mecânicas muito inferiores às condições que apresentaram vazios internos a lente de soldagem. A solda que não continha defeitos apresentou os melhores resultados de propriedades mecânicas em relação a todas as condições investigadas.
8

Multiklassificering av reservdelar : En fallstudie om anskaffningsstrategi och lagerstyrning / Multicriteria classification of spare parts : A case study of procurement strategies and inventory management

Larsson, Philip, Sörman, Noah January 2019 (has links)
Syfte – Syftet med studien är ”…att undersöka hur anskaffning av reservdelar kan effektiviseras, utifrån multipla klassificeringsaspekter”. För att besvara syftet har tre frågeställningar formulerats: 1. Vilka aspekter är viktiga vid anskaffning av reservdelar? 2. Hur kan reservdelar klassificeras utifrån aspekterna? 3. Vilka anskaffningsstrategier kan tillämpas på de olika kategorierna av reservdelar? Metod – Studien utfördes som en fallstudie där målet var att studera ett fallföretags processer i deras naturliga sammanhang. Studiens data insamlades via en dokumentstudie samt tre intervjuer med administrativ personal vilket användes tillsammans med tidigare akademisk litteratur. Resultat – Både tidigare teori och insamlad empiriska data pekade på fyra aspekter att beakta vid anskaffning av reservdelar; kriticitet, ledtid, efterfrågan och kostnad. Reservdelarna kunde utefter de fyra beskrivna aspekterna separat tilldelas en klassificering, där flera metoder kombineras till en multiklassificering-modell. Efter klassificering möjliggjordes utformningen av olika anskaffningsstrategier med lämpliga lagerpolicyers, partiformningsmetoder, orderpunkter och övervakningsmetoder för diverse kategori, för att effektivisera lagerstyrningen. Implikationer – Studiens resultat visar en möjlig kombination för att utföra en multiklassificering baserad på kriticitet, ledtid, efterfrågan och kostnad. En sådan klassificering kan hjälpa företag som är starkt beroende av reservdelar att veta vilka reservdelar som mest fokus bör läggas på i anskaffningen. Begränsningar – Studien innefattade enbart ett företag vilket reducerar dess generaliserbarhet. Fallföretaget var dessutom I underhållsbranschen vilket medförde att reservdelar användes till att underhålla kunders produkter och inte egen utrustning.
9

Using functionalized gold nanoparticles to determinate environmental samples and biomolecules

Lai, Yi-Jhen 22 June 2011 (has links)
¤@¡BRole of 5-thio-(2-nitrobenzoic acid)-capped gold nanoparticles in the sensing of chromium(VI): remover and sensor This study describes a simple, rapid method for sensing Cr(VI) using 5-thio-(2-nitrobenzoic acid) modified gold nanoparticles (TNBA-AuNPs) as a remover for Cr(III) and as a sensor for Cr(VI). We discovered that TNBA-AuNPs were dispersed in the presence of Cr(VI), whereas Cr(III) induced the aggregation of TNBA-AuNPs. Due to this phenomenon, TNBA-AuNPs can be used as a sorbent material for the removal of > 90% Cr(III), without removing Cr(VI). After centrifuging a solution containing Cr(III), Cr(VI), and TNBA-AuNPs, Cr(III) and Cr(VI) were separately present in the precipitate and supernatant. In other words, TNBA-AuNPs are capable of separating a mixture of Cr(III) and Cr(VI). The addition of ascorbic acid to the supernatant resulted in a reduction of Cr(VI) to Cr(III), driving the aggregation of TNBA-AuNPs. The selectivity of this approach is more than 1000-fold for Cr(VI) over other metal ions. The minimum detectable concentration of Cr(VI) was 1 £gM using this approach. Inductively coupled plasma mass spectrometry provided an alternative for the quantification of Cr(III) and Cr(VI) after a mixture of Cr(III) and Cr(VI) had been separated by TNBA-AuNPs. The applicability of this approach was validated through the analysis of Cr(VI) in drinking and tap water. ¤G¡BFluorescent Sensing of Total, Protein-bound, Free, and Oxidized Homocysteine in Plasma through the Combination of Tris(2-carboxyethyl)Phosphine Reduction, Fluorosurfactant-Capped Gold Nanoparticles Extraction, and o-Phthaldialdehyde Derivatization This study reports a simple, selective, and sensitive method for fluorescent detection of total, protein-bound, free, and oxidized homocysteine (HCys) using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent, fluorosurfactant-capped gold nanoparticles (FSN-AuNP) as a preconcentrating probe, and o-Phthaldialdehyde (OPA) as a derivatizing agent. TCEP was used to reduce the disulfide bonds of protein-bound and oxidized HCys. FSN-AuNPs were capable of extracting HCys from a complicated complex because the FSN capping layer can stabilize the AuNPs in a high-salt solution and inhibit non-specific adsorption. HCys was selectively derivatized with OPA in the absence of a nucleophile. By taking advantage of these features, the selectivity of the proposed system is greater than 100-fold for HCys and homocystine (HCys-HCys disulfide; diHCys) compared to any aminothiols. The limits of detection (LODs) for HCys and diHCys were 4.4 and 4.6 nM, respectively. Compared to other sensors, the proposed system provides an approximately 3-300-fold improvement in the detection of HCys. Different forms of plasma HCys were determined by varying the order of disulfide reduction with TCEP. The proposed system was successfully applied to determine the total, protein-bound, free, and oxidized HCys in plasma. To the best of our knowledge, the proposed system not only provides the first method for detecting various forms of plasma HCys, but also has the lowest LOD value for HCys when compared to other sensors.

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