Iron sulfur (FeS) clusters are ubiquitous metallocofactors required by a large number of proteins involved in myriad cellular processes. Nuclear and cytosolic FeS proteins depend on the cytosolic iron sulfur cluster assembly (CIA) pathway for cluster acquisition. The CIA pathway begins with a scaffolding complex, comprising Nbp35 and Cfd1 in Saccharomyces cerevisiae. Nbp35 and Cfd1 each harbor a deviant Walker A domain for nucleotide hydrolysis that is essential for their FeS cluster scaffolding activity. Since there is little information about the CIA scaffold’s nucleotide hydrolysis activity, it has been challenging to discern the role nucleotide is playing in FeS cluster biogenesis. This thesis investigates the nucleotide driven steps of FeS cluster assembly and transfer, and the individual roles of the scaffold subunits Nbp35 and Cfd1. First addressed was answering the question of why two different scaffold subunits are needed for CIA function, and identifying the scaffold’s quaternary structure. Size exclusion chromatography revealed that the CIA scaffold exists as homodimers and heterodimers. Only Nbp352 and Nbp35-Cfd1 exhibited detectable ATPase activity. Though Cfd12 did not have detectable ATPase activity, it bound nucleotide with an affinity comparable to Nbp352 and Nbp35-Cfd1. Site directed mutagenesis and nucleotide binding studies revealed that the Cfd1 subunit is the high affinity binding site for ATP in Nbp35-Cfd1, and that the Nbp35 subunit binds nucleotide at saturating concentrations. Cfd1 therefore controls nucleotide binding in Nbp35-Cfd1. Additionally, it was found that the Cfd1 subunit is hydrolysis competent when complexed with Nbp35, identifying Nbp35 as an activator of Nbp35-Cfd1’s ATPase activity. Next, ATP’s role in FeS cluster biogenesis by CIA was identified. Mutation of the ATPase domain of Nbp35 impaired the ability of the scaffold to assemble and transfer FeS clusters in vivo. Four phenotypes were identified by observing how each mutation affected the scaffold’s nucleotide binding and hydrolysis. In vitro experiments established that cluster occupancy of the bridging cluster site of Nbp35-Cfd1 decreased the scaffold’s affinity for nucleotide. These results support a model of FeS cluster biogenesis in which nucleotide binding and FeS cluster binding regulate one other, with the bridging cluster site translating information to the ATPase site and vice versa. Nucleotide binding is also proposed to drive a conformational change that mediates interaction with another CIA component, later identified as Dre2. Dre2 was found to stimulate the rate of ATP hydrolysis by Nbp35-Cfd1 in an FeS cluster dependent manner. It is likely that nucleotide hydrolysis is then needed for the scaffold to assemble and/or transfer the FeS cluster. The results of these experiments have allowed us to describe the critical role of nucleotide in FeS biogenesis by CIA and explain the requirement for two distinct scaffold subunits. Finally, a fluorescent [Fe4S4] cluster sensor based on bacterial FNR (fumarate and nitrate reductase transcription factor) was designed, developed, and tested for practicality. FNR was fused to a SNAP tag protein which was then covalently labeled with a fluorescent molecule. The loss of cluster by the sensor resulted in an increase in fluorescence intensity, due to the cluster’s ability to quench fluorescence. As such, cluster decay rates could be measured as a function of increasing fluorescence intensity. The rates observed via fluorescence followed the same trends as the rates obtained by measuring the decay of clusters via absorbance. Encouragingly, the rates observed for the cluster decay were similar to decay rates determined previously via alternative methods.

No description available.

Dans ce travail, une configuration laminaire stratifiée est utilisée afin d’étudier les caractéristiques de la pyrolyse et de l’oxydation du charbon pulvérisé dans un mélange de flux réactif à la fois dans les conditions atmosphériques conventionnelles et dans des conditions de combustion enrichie en oxygène. Deux diagnostics optiques, la spectroscopie d’émission de flamme et la mesure de l’émission spontanée sont utilisés pour caractériser la structure de la flamme. Les profiles de concentration de trois radicaux excités, OH*, CH* and C*2 sont mesurés et analysés.Des simulations 1-D utilisant la cinétique détaillée y compris des sous-mécanismes de OH*, CH* and C*2 et de combustion de charbon sont effectuées et comparées avec des données expérimentales. La comparaison qualitative a montré que la configuration numérique actuelle était appropriée pour la prédiction des émissions de OH*, CH* and C*2. Les résultats prédits par l’approche numérique diffèrent avec les modifications apportées aux sous-modèles de charbon et aux paramètres cinétiques. Le modèle de pyrolyse et les matières volatiles semblent jouer des rôles plus importants. / In the present work, a laboratory-scale laminar strained configuration is used to investigate the characteristics of pulverized coal devolatilization and oxidation in a mixture of CH4/O2/N2 reactive flow both in conventional air conditions and in oxygen-enriched combustion conditions. Two optical diagnostics, Flame Emission Spectroscopy and measurement of spontaneous emission, are employed for the characterization of flame structure. The spatial concentration evolution of three excited radicals, OH*, CH*and C*2 , are measured and analyzed.1-D simulations using detailed gas-phase kinetics including OH*, CH*, and C*2 sub-mechanisms and coal combustion submodels are performed and compared with experimental data. Qualitative comparison with experiments showed that the current numerical configuration was suitable for the prediction of OH*, CH* and C*2 emission. The predicted results differed with changes to the coal sub-models and kinetic parameters. The devolatilization model and volatile matters seem to play more important roles.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-06-18T19:16:59Z No. of bitstreams: 1 Aline Marina Alves Fruhauf.pdf: 1453096 bytes, checksum: 48897b7f7729d68294f85c6738b2da54 (MD5) / Made available in DSpace on 2018-06-18T19:16:59Z (GMT). No. of bitstreams: 1 Aline Marina Alves Fruhauf.pdf: 1453096 bytes, checksum: 48897b7f7729d68294f85c6738b2da54 (MD5) Previous issue date: 2016-02-17 / Increased cortical activity induced by brain stimulation, associated or not with other rehabilitation techniques, may potentiate the therapeutic effects in patients with neurological deficits. To assess the immediate effects of two related techniques, transcranial direct-current stimulation (tDCS) and functional electrical stimulation (FES), the electrical activity of the tibialis anterior (TA) and static balance of individuals with post stroke hemiparesis. Methods: clinical trial, controlled, randomized, double-blind, 30 individuals hemiparesis due to stroke. Rating: median frequency and RMS TA by electromyography (EMG) and evaluation of static balance (area, speed and frequency of oscillation in open eyes (OE) and closed (CE)) by stabilometry. Interventions: 4 protocols with 48h interval: 1 (tDCS anodic + FES sham), 2 (tDCS sham + FES active), 3 (tDCS anodic + FES active) and 4 (tDCS sham + FES sham). The anode was applied on etcc C3 and / or C4 and cathode on the contralateral supraorbital region and FES on hemiparetic TA for 20 minutes. Results: There was no statistically significant difference (p> 0.05) of the median frequency and RMS for the acquisition of isotonic and maximal voluntary isometric contraction (MVIC) of TA and static balance both OE and CE condition of the protocols by the Friedman test . Conclusion: There was no difference in the electrical activity of the TA muscle and static balance after application of the associated technical or isolated. The application time may not be enough to verify a motor learning, moreover, it is suggested that the tDCS may have a cortical hyperexcitability generated response any competitor inhibiting action; and a second hypothesis is that the stimulation of both the FES or active contraction has generated supposed peripheral fatigue, even with preconization contractions to avoid that this factor. It is believed that the two suggestive lead to additive effects (a technique inhibiting possibly other). / O aumento da atividade cortical, induzido pela estimulação cerebral, associado ou não com outras técnicas de reabilitação, pode potencializar os efeitos terapêuticos em indivíduos com déficits neurológicos. Objetivos: Avaliar os efeitos imediatos de duas técnicas associadas, estimulação transcraniana por corrente contínua (ETCC) e estimulação elétrica funcional (FES), na atividade elétrica do músculo tibial anterior (TA) e equilíbrio estático de indivíduos com hemiparesia pós acidente vascular encefálico (AVE). Métodos: Ensaio clínico, controlado, randomizado, duplo cego, em 30 indivíduos hemiparéticos decorrente de AVE. Avaliações: frequência mediana e RMS do TA por eletromiografia (EMG) e avaliação do equilíbrio estático (área, velocidade e frequência de oscilação em olhos abertos (AO) e fechados (OF)) por estabilometria. Intervenções: 4 protocolos com intervalo de 48h: 1 (ETCC anódica + FES placebo), 2 (ETCC placebo + FES ativo), 3 (ETCC anódica + FES ativo) e 4 (ETCC placebo + FES placebo). A ETCC anódica foi aplicada sobre C3 e/ou C4 e catódica sobre região supraorbital contralateral e FES sobre TA hemiparético,durante 20 minutos. Resultados: Não houve diferença estatisticamente significante (p > 0,05) da frequência mediana e RMS durante as aquisições de isotonia e contração isométrica voluntária máxima (CIVM) do TA e equilíbrio estático tanto na condição OA e OF entre os protocolos pelo teste de Friedman. Conclusão: Não houve diferença na atividade elétrica do músculo TA e equilíbrio estático, após aplicação das técnicas associadas ou isoladas. O tempo de aplicação pode não ter sido insuficiente para se verificar um aprendizado motor, além disso, sugere-se que a ETCC possa ter gerado uma resposta de hiperexcitabilidade cortical inibindo qualquer ação concorrente; e uma segunda hipótese seria que o estímulo tanto da FES ou da contração ativa tenha gerado suposta fadiga periférica, mesmo com preconização das contrações para que se evitasse esse fator. Acredita-se que as duas sugestivas, levaram a efeitos aditivos (uma técnica possivelmente inibindo a outra).

Iron chemistry plays an important role in our world. At the nanoscale, iron oxide nanoparticles (nanomagnetite) have many inherent physical or chemical characteristics that drive potential solutions to real-world problems; appropriation of nanomagnetite’s properties as a “scaffold” for chemistry would further enhance its effectiveness in applications. In an effort to make use of nanomagnetite’s physical properties, a new “Sulfide Green Rust” (sGR) has been synthesized from magnetic iron nanoparticles. The material is crystalline, reactive due to high iron(II) content, and dissolves in the aqueous phase. Nanomagnetite’s magnetic properties were also observed to persist after sGR synthesis. X-ray absorption spectroscopy (XAS) confirmed the synthesis of this new FeS2-like material. The crystallinity, composition, and various physical characteristics were examined using a host of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Mössbauer spectroscopy, CRYO-TEM, Raman spectroscopy, and ultraviolet-to-visible (UV-Vis) spectroscopy. To demonstrate its use, the material was then subjected to a test of its reactive potential, namely water remediation of an orange dye contaminant. Iron serves a function at the macroscale as well regarding water treatment, since iron coagulation-filtration is the industry standard for arsenic treatment. Determining a technology’s merit as a solution goes beyond technical concern, however, as environmental and economic aspects also play important roles. Life Cycle Analysis, or LCA, methodology works to holistically compare each of these facets from cradle to grave. To address the current arsenic drinking water requirements at a case setting in Hungary, the LCA technique was applied on two example arsenic removal technologies, both coagulation-filtration and adsorption. 9 out of 10 considered impact categories tended to favour coagulation-filtration in this small municipality study, however realistic variations in water chemistry and product characteristics led to some overlap of their environmental impact. Electricity did not have a large direct impact, regeneration of the adsorption technology was very costly, and adsorption’s hazardous waste was not reduced compared to coagulation-filtration. Coagulation-filtration is also the cheaper of the two technologies; its highest cost is that of waste disposal, while the highest single expense modeled is that of adsorption media cost.

Noise and time-dependent fluctuations are usually undesirable signals. However, they have many applications. This dissertation deals with two kinds of sensing applications of fluctuation and noise: soil bulk density assessment and bacterium sensing. The measurement of Vibration-Induced Conductivity Fluctuations (VICOF) provides information about the bulk density and other parameters of soils. Bulk density is the physical property of soils that is important to both the agriculture and construction industries. The traditional measurements of soil bulk density are often time-consuming, expensive or destructive. To determine the soil bulk density without the above drawbacks, the VICOF measurement scheme was proposed. The research of VICOF in this dissertation includes two parts: the initial phase of study and the new methods and their theory. In the initial phase of study, the simple experiments, theory, and simulations of VICOF were tested for relations between the soil bulk density, wetness, salinity, and the VICOF data. Then, new measurement arrangements and their theoretical models were proposed to improve the weaknesses of the initial approach (such as large scattering of data due to loose and heavy contacts) and to calculate the relationship between the measured signals and the electromechanical transport parameters of the soils. The bacterium sensing study in this dissertation was proposed to explore simple, practical, rapid, sensitive, specific, portable, and inexpensive ways to detect and recognize bacteria by Fluctuation-Enhanced Sensing (FES). One such potential way of bacterium sensing is to analyze their odor. The research of bacterium sensing also includes two parts: the initial phase of study and the new methods and their theory. The initial phase study was proposed to explore the possibility of detecting and identifying bacteria by sensing their odor via FES with commercial Taguchi sensors. Then the subsequently developed new methods and their theory provide a simple way to generate binary patterns with perfect reproducibility based on the spectral slopes in different frequency ranges at FES. This new type of signal processing and pattern recognition is implemented at the block diagram level using the building elements of analog circuitries and a few logic gates with total power consumption in the microWatts range.

The fps proto-oncogene encodes a 92 kDa cytoplasmic tyrosine kinase. Previous studies have shown that Fps expression in the mammary gland changes with development, and Fps has a suppressor function in mammary tumorigenesis. The aim of my thesis was to elucidate the role of the Fps tyrosine kinase in regulating mammary gland development and function. We have shown that the expression of the Fps kinase in the mammary gland increased during pregnancy and reached its maximum during lactation. The level of Fps tyrosine phosphorylation paralleled the expression pattern. Pups reared by fps-null females gained weight more slowly than those reared by wild-type females. Epithelial cells were the primary source of Fps expression. Milk protein and fat content were not affected by the absence of Fps. Similarly, no differences in mammary gland structure were observed with whole mount or histological analysis. Fps was shown to be in a multi-protein complex with E-cadherin, β-catenin and p120-catenin. A strong co-localization signal was observed for Fps and E-cadherin. Immunofluorescence analysis indicated that the localization of E-cadherin and β-catenin was disorganized and less concentrated at sites of cell-cell contacts in the fps-null glands. The interactions between the different adherens junction components were altered in the fps-null tissue. Specifically, less E-cadherin and β-catenin was associated with p120-catenin in the fps-null glands. Suprisingly, no phosphotyrosine differences were detected for the adherens junction components. Conditions were established to grow primary murine epithelial cell cultures that could be used to investigate the function of Fps. Fps expression was up-regulated in these cells in response to lactogenic hormones. A lentiviral system encoding a murine p53 shRNA sequence was used to increase the growth potential of the primary cells. Continual growth of the infected and uninfected primary epithelial cell mixture resulted in the establishment of an immortalized cell line. Immunofluorescent and immunoblot analyses revealed that the cells have undergone an epithelial-to-mesenchymal transition. With the transduction of a myc-epitope tagged Fps into the cells, we have generated cell lines with the appropriate genetic backgrounds to study the function of the Fps kinase in the mammary gland, specifically as it relates to tumorigenesis. / Thesis (Ph.D, Pathology & Molecular Medicine) -- Queen's University, 2008-07-03 11:53:01.135

FES protein-tyrosine kinase (PTK) activation downstream of the KIT receptor in mast cells (MC) promotes cell polarization and migration towards the KIT ligand Stem cell factor (SCF). A variety of tumours secrete SCF to promote MC recruitment and release of mediators that enhance tumour vascularization and growth. This study investigates whether FES promotes MC migration via regulation of microtubules (MTs), and if FES is required for MC recruitment to the tumour microenvironment. MT binding assays showed that FES has at least two MT binding sites, which likely contribute to the partial co-localization of FES with MTs in polarized bone marrow-derived mast cells (BMMCs). Live cell imaging revealed a significant defect in chemotaxis of FES-deficient BMMCs towards SCF embedded within an agarose drop, which correlated with less MT organization compared to control cells. To extend these results to a tumour model, mouse mammary carcinoma AC2M2 cells were engrafted under the skin and into the mammary fat pads of immune compromised control (nu/nu) or FES-deficient (nu/nu:fes-/-) mice. A drastic reduction in tumour-associated MCs was observed in FES-deficient mice compared to control in both mammary and skin tissue sections. This correlated with a trend towards reduced tumour volumes in FES-deficient mice. These results implicate FES signaling downstream of KIT, in promoting MT reorganization during cell polarization and for chemotaxis of MCs towards tumour-derived SCF. Thus, FES is a potential therapeutic target to limit recruitment of stromal mast cells or macrophages to solid tumours that enhance tumour progression. / Thesis (Master, Biochemistry) -- Queen's University, 2011-09-14 11:49:32.871

Thesis--Columbia University. / Includes index. Bibliography: p. [206]-211.

Introduktion: Fallolyckor bland äldre orsakar stora samhällskostnader och bidrar även till stort lidande i det vardagliga livet. Bortsett från fysiska skador så är fallrädsla även ett stort folkhälsoproblem. Fallrädsla defineras som en upplevd frånvaro av trygghet för att hålla balans vid aktiviteter, som resulterar till en mängd olika hälsoproblem. Vanligtvis används Fall Efficacy Scale - International (FES-I) och Activities-specific Balance Confidence Scale (ABC-scale) som bedömningsinstrument för självskattning av fallrädsla. Däremot så saknas utvärdering av fallrädsla utifrån ett funktionellt perspektiv. Late-Life Function and Disability Instrument (LLFDI) är ett självskattningsformulär som ursprungligen utformats för bruk vid intervjuer för äldre 60 år och uppåt.Syfte: Syftet med denna studie var att undersöka om det finns ett samband mellan självskattad funktionsnivå enligt LLFDI samt självskattad fallrädsla enligt Iconographical - Falls Efficacy Scale (Icon-FES) och ABC scale bland äldre personer över 70 år. Delsyftet var att undersöka korrelationen bland de tre domänerna i LLFDI för att se vilka nedsättningar som korrelerar bäst med fallrädsla. Metod: Sambandet mellan skattad funktion enligt LLFDI samt upplevd fallrädsla enligt ABS-scale och Icon-FES undersöktes med Spearmans Rho i ett datamaterial med 67 deltagare över 70 år som deltagit i en tidigare studie av fallpreventiv träning. Resultat: En hög statistisk signifikant korrelation enligt Hinkel hittades mellan de funktionella domänerna hos LLFDI och ABC-scale (FU och GNE) och Icon-FES (FU och ANE). Måttliga korrelationer observerades även mellan LLFDI och ABC-scale (ANE) och Icon-FES (GNE). Enbart en domän övre extremitet visade väldigt låg korrelation med fallrädsla.  Slutsats: Eftersom hög korrelation kundes ses bidrar resultat stärker det sambandet mellan självskattad funktion och fallrädsla bland äldre som bor i en hemmiljö. Framtida studier bör undersöka resultatet bland ett könsuppdelat stickprov i form av en tvärsnittsstudie för att mäta prevalens av fallrädsla samt exponering av fysisk inaktivitet os deltagarna.