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Cherubal, Sasikumar. "Fault isolation and diagnosis techniques for mixed-signal circuits." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15450.
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Zhang, Norman Tianshu. "Isolation of lactoferrin from bovine colostrum by chromatographic techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0010/MQ59911.pdf.
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Meseguer, Amela Jordi. "Integration Techniques of Fault Detection and Isolation Using Interval Observers." Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/52812.
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An interval observer has been illustrated to be a suitable approach to detect and isolate faults affecting complex dynamical industrial systems.
Concerning fault detection, interval observation is an appropriate passive robust strategy to generate an adaptive threshold to be used in residual
evaluation when model uncertainty is located in parameters (interval model). In such approach, the observer gain is a key parameter since it determines
the time evolution of the residual sensitivity to a fault and the minimum detectable fault. This thesis illustrates that the whole fault detection process is
ruled by the dynamics of the fault residual sensitivity functions and by the time evolution of the adaptive threshold related to the interval observer.
Besides, it must be taken into account that these two observer fault detection properties depend on the used observer gain. As a consequence, the
observer gain becomes a tuning parameter which allows enhancing the observer fault detection performance while avoiding some drawbacks related to
the analytical models, as the wrapping effect. In this thesis, the effect of the observer gain on fault detection and how this parameter can avoid some
observer drawbacks (i.e. wrapping effect) are deeply analyzed. One of the results of this analysis is the determination of the minimum detectable fault
function related to a given fault type. This function allows introducing a fault classification according to the fault detectability time evolution:
permanently (strongly) detected, non-permanently (weakly) detected or just non-detected. In this fault detection part of this thesis, two examples
have been used to illustrate the derived results: a mineral grinding-classification process and an industrial servo actuator.
Concerning the interface between fault detection and fault isolation, this thesis shows that both modules can not be considered separately since the
fault detection process has an important influence on the fault isolation result. This influence is not only due to the time evolution of the fault signals
generated by the fault detection module but also to the fact that the fault residual sensitivity functions determines the faults which are affecting a given
fault signal and the dynamics of this fault signal for each fault. This thesis illustrates this point suggesting that the interface between fault detection and
fault isolation must consider a set of fault signals properties: binary property, sign property, fault residual sensitivity property, occurrence order property
and occurrence time instant property. Moreover, as a result of the influence of the observer gain on the fault detection stage and on the fault residual
sensitivity functions, this thesis demonstrates that the observer gain has also a key role in the fault isolation module which might allow enhancing its
performance when this parameter is tuned properly (i.e. fault distinguishability may be increased). As a last point, this thesis analyzes the timed
discrete-event nature of the fault signals generated by the fault detection module. As a consequence, it suggests using timed discrete-event models to
model the fault isolation module. This thesis illustrates that this kind of models allow enhancing the fault isolation result. Moreover, as the monitored
system is modelled using an interval observer, this thesis shows as this qualitative fault isolation model can be built up on the grounds of this system
analytical model. Finally, the proposed fault isolation method is applied to detect and isolate faults of the Barcelona’s urban sewer system limnimeters.
Keywords: Fault Detection, Fault Diagnosis, Robustness, Observers, Intervals, Discrete-event Systems.En la presente tesis se demuestra que el uso de observadores intervalares para detectar y aislar fallos en sistemas dinámicos complejos constituye una estrategia apropiada. En la etapa de detección del fallo, dicha estrategia permite determinar el umbral adaptativo usado en la evaluación del residuo (robustez pasiva). Dicha metodología, responde a la consideración de modelos con parámetros inciertos (modelos intervalares). En dicho enfoque, la ganancia del observador es un parámetro clave que permite determinar la evolución temporal de la sensibilidad del residuo a un fallo y el mínimo fallo detectable para un tipo de fallo determinado. Esta tesis establece que todo el proceso de detección de fallos viene determinado por la dinámica de las funciones sensibilidad del residuo a los diferentes fallos considerados y por la evolución temporal del umbral adaptativo asociado al observador intervalar. Además, se debe tener en cuenta que estas dos propiedades del observador respecto la detección de fallos dependen de la ganancia del observador. En consecuencia, la ganancia del observador se convierte en el parámetro de diseño que permite mejorar las prestaciones de dicho modelo respecto la detección de fallos mientras que permite evitar algunos defectos asociados al uso de modelos intervalares, como el efecto wrapping. Uno de los resultados obtenidos es la determinación de la función fallo mínimo detectable para un tipo de fallo dado. Esta función permite introducir una clasificación de los fallos en función de la evolución temporal de su detectabilidad: fallos permanentemente detectados, fallos no permanentemente detectados y fallos no detectados. En la primera parte de la tesis centrada en la detección de fallos se utilizan dos ejemplos para ilustrar los resultados obtenidos: un proceso de trituración y separación de minerales y un servoactuador industrial. Respecto a la interfaz entre la etapa de detección de fallos y el proceso de aislamiento, esta tesis muestra que ambos módulos no pueden considerarse separadamente dado que el proceso de detección tiene una importante influencia en el resultado de la etapa de aislamiento. Esta influencia no es debida sólo a la evolución temporal de las señales de fallo generados por el módulo de detección sino también porque las funciones sensibilidad del residuo a los diferentes posibles fallos determinan los fallos que afectan a un determinado señal de fallo y la dinámica de éste para cada uno de los fallos. Esta tesis ilustra este punto sugiriendo que el interfaz entre detección y aislamiento del fallo debe considerar un conjunto de propiedades de dichos señales: propiedad binaria, propiedad del signo, propiedad de la sensibilidad del residuo a un fallo dado, propiedad del orden de aparición de las señales causados por los fallos y la propiedad del tiempo de aparición de estos. Además, como resultado de la influencia de la ganancia del observador en la etapa de detección y en las funciones sensibilidad asociadas a los residuos, esta tesis ilustra que la ganancia del observador tiene también un papel crucial en el módulo de aislamiento, el cual podría permitir mejorar el comportamiento de dicho módulo diseñando éste parámetro del observador de forma adecuada (Ej. Incrementar la distinción de los fallos para su mejor aislamiento). Como último punto, esta tesis analiza la naturaleza temporal de eventos discretos asociada a las señales de fallo generados por el módulo de detección. A consecuencia, se sugiere usar modelos de eventos discretos temporales para modelizar el módulo de aislamiento del fallo. Esta tesis muestra que este tipo de modelos permite mejorar el resultado de aislamiento del fallo. Además, dado que el sistema monitorizado es modelado usando un observador intervalar, esta tesis muestra como este modelo cualitativo de aislamiento puede ser construido usando dicho modelo analítico del sistema. Finalmente, el método propuesto de aislamiento del fallo es aplicado para detectar y aislar fallos en los limnimetros del sistema de alcantarillado de Barcelona. Palabras clave: Detección de Fallos, Diagnosis de Fallos, Robusteza, Observadores, Intervalos, Sistemas de Eventos Discretos.
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Meiklejohn, Bruce Ian 1959. "ISOLATION AND SEPARATION OF HUMAN CYTOKERATINS USING VARIOUS CHROMATOGRAPHIC TECHNIQUES." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276475.
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The cytokeratins from various human tissue were isolated using chromatographic techniques. The cytokeratins were first extracted from crude tissue using high and low salt buffers. It was necessary to use a denaturing agent such as urea to solubilize the resulting cytokeratin pellet. Imidazole also seemed to help solubilize the pellet and a reducing agent such as 2-Mercaptoethanol was not needed as previously believed. The acidic cytokeratins were separated from the neutral-basic cytokeratins using a DEAE ion-exchange column. The acidic cytokeratin fraction was further separated on a moderately polar reverse phase column with an acetonitrile gradient to eluted the proteins. Tetramethylammonium tetrafluoroborate was added to the mobile phase to react with any unreacted silanol groups on the stationary phase and trifluoroacetic acid was added to ion pair with the protein. The peaks were analyzed for purity using two dimensional electrophoresis and monoclonal antibodies that recognize the cytokeratins.
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Hwas, Abdulhamed. "Model-based fault detection and isolation techniques for wind turbines." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25512.
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The main objective of the work of this thesis is to design model-based fault detection and isolation techniques for a large-scale wind turbine. A mathematical model of the 5MW wind turbine was developed; the model was sufficiently detailed to be used for simulation purposes. The stages of the modelling procedure were to divide the overall wind turbine system into appropriate sub-models suitable for separate modelling. Each sub-model was then presented and combined in order to obtain a completed non-linear wind turbine model. Two methods are proposed to calculate the gains of a proportional-integral (PI) pitch angle controller for the non-linear model: the first method is analytical and the second method is based on simulation. The simulation results demonstrated good performance for both proposed PI schemes. In order to design an electrical torque controller, an internal model controlbased PI controller was used to find the gains of the current and of the torque controller; good static and dynamic performance were achieved. In this thesis, a quantitative model-based method for early detection and diagnosis of wind turbine faults is proposed. The method is based on designing an observer by using a linear model of the system; the observer innovation signal is monitored to detect faults. The fault detection system was designed and optimised to be maximally sensitive to system faults and minimally sensitive to system disturbances and noise; a multi-objective optimisation method was utilised to address this dual problem. Simulation results are presented to demonstrate the performance of the proposed method. Next, a non-linear observer-based scheme for early fault detection and isolation of wind turbines was developed. The method is based on designing a nonlinear observer using a non-linear model of the wind turbine. The state-dependent differential Riccati equation was used to design a non-linear observer. The comparison of system outputs with non-linear observer estimation confirmed good performance of the non-linear observer. Based on the non-linear observer, a residual generator for monitoring wind turbine model was formulated. Simulation results illustrated that the proposed method is a robust method in detecting and isolating a single fault or multi-faults in wind turbine sensors.
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Moulin, Laurent. "Applications des techniques de contrôle actif à divers problèmes de bruit dans le bâtiment." Ecully, Ecole centrale de Lyon, 1995. http://www.theses.fr/1995ECDL0017.
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Notre étude se propose d'appliquer les techniques actives à deux problèmes de bruit dans le bâtiment. La première partie de la thèse concerne les investigations expérimentales menées afin de minimiser, à l'aide d'un système actif multivoies, le rayonnement acoustique de muscles supérieurs dans un conduit rectangulaire à parois rigides. La deuxième partie relate les expériences réalisées afin d'améliorer l'isolation passive d'un double vitrage.
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Chin, Eu-Jeen. "High performance vibration isolation techniques for the AIGO gravitational wave detector." University of Western Australia. School of Physics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0159.
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[Truncated abstract] Interferometric gravitational wave detectors are being built around the world with continually improving measurement sensitivities. Noise levels from sources that are intrinsic to these detectors must be reduced to a level below the gravita- tional wave signal. Seismic noise in the low frequency range, which is within the gravitational wave detection bandwidth, is a concern for earth-based detectors. This thesis presents research and development of a high performance vibration isolation system that is designed to attenuate seismic noise. The final design will be used as part of a fully working interferometer at the Australian International Gravitational Observatory (AIGO). Pendulums and springs are conventionally used for the horizontal and vertical vibration isolation components respectively. A complete system comprises of a cascade of these components, each stage dramatically improving the level of isola- tion. The residual motion at the test mass level is thus reduced but is dominated by the normal mode resonances of the chain. A simple and effective method to reduce residual motion further is to add ultra-low frequency pre-isolation stages which suspend the chain. The Roberts Linkage is a relatively new and simple geometrical structure that is implemented in the pre-isolation stages. Here we present experimental results of improving isolation based on mathematical mod- elling. The attenuation of seismic noise in the vertical direction is almost as important as that in the horizontal direction, due to cross-coupling between the two planes. To help improve the vertical performance a lightweight Euler spring that stores no static energy was implemented into the AIGO suspension system. ... Theoretical and experimental results are presented and discussed. Currently the AIGO laboratory consists of two 80 m length arms. They are aligned along the east and south directions. One of AIGO's top priorities is the installation of two complete vibration isolators in the east arm to form a Fabry-Perot cavity. Assembling two suspension systems will enable more accurate performance measurements of the tuned isolators. This would significantly reduce the measurement noise floor as well as eliminate the seismic noise spectrum due to referencing with the ground motion. The processes involved in preparing such a task is presented, including clean room preparation, tuning of each isolator stage, and local control schematics and methods. The status of the AIGO site is also presented.
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Ingram, David. "An Evaluation of Harmonic Isolation Techniques for Three Phase Active Filtering." Thesis, University of Canterbury. Electrical and Computer Engineering, 1998. http://hdl.handle.net/10092/1260.
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Recent advances in power electronics have lead to the wide spread adoption of advanced power supplies and energy efficient devices. This has lead to increased levels of harmonic currents in power systems, degrading the performance of electrical machinery and interfering with telecommunication services. Active filters provide a solution to these problems by compensating for the distorted currents drawn by non-linear loads. Optimal methods for controlling these active filters have been determined by computer simulation and experimental implementation. Methods used for isolating the harmonic content of an unbalanced three phase load current were compared by computer simulations. A technique based on the Fast Fourier Transform (FFT) was developed as part of this work and shown to perform favourably. Notch Filtering, Sinusoidal Subtraction, Instantaneous Reactive Power Theory, Synchronous Reference Frame and Fast Fourier Transform methods were simulated. The methods shown to be suitable for compensation of three phase unbalanced loads were implemented in a Digital Signal Processor to evaluate true performance. These methods were Notch Filtering, Sinusoidal Subtraction, Fast Fourier Transform, and a High Pass Filter based method. A completely digital hysteresis current controller for a three phase active filter inverter has been developed and implemented with a Field Programmable Gate Array. This controller interfaces directly to a digital signal processor and is resistant to electromagnetic interference. Results from the experimental hardware verified that the active filter model used for simulation is accurate, and may be used for further development of harmonic isolation methods. A technique using notch filtering gives the best performance for steady loads, with the FFT based technique giving the most flexible operation for a range of load current characteristics. Novel use of the FFT based harmonic isolation technique allows selective cancellation of individual harmonics, with particular application to multiple shunt filters connected in parallel.
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Walker, Mathew William. "Improved techniques for isolation of pure cellular organelles with magnetic ferrofluid." Thesis, Cardiff University, 2015. http://orca.cf.ac.uk/70620/.
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Lysosomes are essential cellular organelles known to be the main site for the breakdown and recycling of endocytosed macromolecules within cells. However, our knowledge of lysosomal function has changed considerably over the last decade with the lysosome now being a recognized Ca2+ signaling organelle with additional roles in plasma membrane repair, clearance of defective organelles and mediating cell death as well as established roles in clearing infection. Our ability to study these unique organelles has however been stymied by a dearth of good techniques for the purification of functional lysosomes not contaminated by other organelles.
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Helmy, Ahmed. "Characterization of substrate noise coupling, its impacts and remedies in RF and mixed-signal ICs." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1160150387.
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Avent, N. D. "Isolation and characterization of erythrocyte membrane components that express the rhesus and related blood group antigens." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233769.
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Giancaterino, Sara. "Isolation of extracellular vesicles from citrus limon fruit through membrane-based techniques." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/22628/.
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The project is aimed at the development of a membrane-based protocol for the isolation of plant-derived extracellular vesicles. In particular, citrus limon fruit is selected as source material, due to its beneficial phyto-properties, availability and cheapness. In the chosen strategy the focus is placed upon the development of a protocol potentially suitable for large-scale operations, conversely to differential ultracentrifugation method, the benchmark in extracellular vesicles production, whose applicability is limited to lab-scale operations. In this context dead-end and crossflow MF/UF units are compared, both as concentration and purification steps. Followingly, the isolated vesicles ware analysed and characterized with SEC liquid chromatography and both physical and biochemical methods. Finally, passive cargo loading techniques are applied to the isolated vesicles to test their encapsulation capability with bioactive phytocomponents, as curcumin.
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Maisuradze, Giorgi [Verfasser], and Christian [Akademischer Betreuer] Rossow. "Assessing the security of hardware-assisted isolation techniques / Giorgi Maisuradze ; Betreuer: Christian Rossow." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/120658873X/34.
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Liu, Qizhi. "Planar photonic devices using surface thin-film stressors and ion implantation isolation techniques /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9804520.
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Raiford, Douglas W. III. "Algorithmic Techniques Employed in the Isolation of Codon Usage Biases in Prokaryotic Genomes." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1211902424.
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Rezaei, Nejad Hojatollah. "Development of techniques for rapid isolation and separation of particles in digital microfluidics." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57956.
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Digital microfluidics (DMF) has emerged as a powerful platform for both research and development in life science studies. The platform functions based on handling small volumes of samples and reagents in the form of discrete droplets using the well-established electrowetting on dielectric (EWOD) method. Based on EWOD, different techniques (operators) have been developed to accurately manipulate, dispense, split and merge droplets of different volumes. Despite the advances made in the DMF technology especially in the use of EWOD in scaling down laboratory procedures, there is lack of understanding and hence development of techniques for particle/cell manipulation and isolation on DMF (as compared to the alternative platform called continuous microfluidics). This has hindered the capability of DMF in full-scale miniaturization of laboratory procedures requiring particle/cell isolation at any of their steps. This research focuses on addressing this problem and developing reliable techniques to manipulate, concentrate and isolate different types of particles/cells. The techniques presented here are particularly developed to limit the use of external devices and also cover a wide range of particles and cells with different physical properties (including size, density, material and electromagnetic properties). They include magnetic collection, hydrodynamic focusing, dielectrophoresis positioning of the particles. The magnetic collection method, a rather simple but effective and widely used in biochemistry, is implemented on DMF for capturing target analytes. The hydrodynamic focusing method, functioning based on the density and size of the particles, were developed and integrated into DMF (for the first time) using especial electrode geometry facilitating the rotation of the droplet. The dielectrophoresis–based particle manipulation is optimized to achieve high resolution and controllability in particle patterning on DMF. The applicability of each of these techniques are demonstrated for different biological and physical applications including on-chip DNA purification (using the magnetic collection technique), ultra-low DNA concentration (using the hydrodynamic focusing technique for achieving desired concentrations of particles), and cell and particle patterning and cell culturing on a DMF platform (using the dielectrophoresis positioning technique). The diversity and flexibility of these techniques will enable the use of DMF devices for especially point-of-care applications.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Mackie, Elizabeth Anne Victoria. "Environmental and relative sea-level reconstruction from isolation basins in NW Scotland using geochemical techniques." Thesis, Durham University, 2004. http://etheses.dur.ac.uk/3033/.
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Isolation basins from Northwest Scotland provide the longest near-field records of relative sea-level (RSL) change in the world (0 to > 16kyr BP). These archives contributed to quantitative models of glacial isostatic adjustment since the last glacial maximum. Isolation basin RSL reconstructions have been primarily based on salinity reconstructions from biological data such as foraminifera and diatoms. However, preservation problems and non-analogue situations can limit their usefulness. Therefore, it is necessary to identify other proxies from isolation basin to improve RSL reconstructions. Also isolation basin sediments are potentially high-resolution records of climate change from both the land and the oceans simultaneously, but little research has been undertaken. This thesis presents the results of a range of isotopic and geochemical measurements that were thought to be suitable proxies for palaeosalinity and palaeoclimate reconstructions. Tephrochronology was also applied to improve the existing geochronological controls of isolation basin sequences by attempting to identify Icelandic tephra layers. A combination of isotopic measurements; δ(^13)Corg, C/N ratios δ(^13)Ctoram, δ(^18)Otoram, (^87)Sr/(^86)Sr from foraminifera and δ(^13)Odiatoms, were preformed on contemporary and fossil archives. Results show δ(^13)Corg, C/N ratios measurements are as sensitive indicators of palaeosalinity, as biological reconstructions on Holocene aged sediment. Overall this thesis highlights the benefits of multi proxy palaeosalinity studies in order to gain a fuller understanding of the complex changes isolation basins experience during an isolation or connection events. A climate signal from an isolation basin that experienced a gradual isolated over the Holocene has been detected for the first time using geochemical techniques biogenic silica (BSi02) and total organic carbon (TOC).
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Millington, K. R. "Structural studies on metal halides and related species using matrix isolation and molecular beam techniques." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380070.
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Maguire, John C. "The Isolation of Human Rod and Cone Photoreceptor Activity combining Electroretinography and Silent Substitution Techniques." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/16833.
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Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones.
Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function.
Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency.
Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges.
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Hines, J. Wesley. "A hybrid approach to fault detection and isolation merging analytical redundancy and neural network techniques /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487859313348358.
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Warner, Julia D. "Transport analysis in polymeric liquids and films: Investigations in ionic mobility isolation techniques and permeability control." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539623430.
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An in situ measurement technique that isolates the mobility of charge carriers is described and analyzed. The technique allows significant improvement over conductivity measurements to monitor changes in the physical properties and state of a material as it cures. This is essential in systems where Ni, the number of charge carriers, cannot be assumed constant such as during cure of epoxies, urethanes and polyimides.;Currently, there is an assumption made in the literature that the number of charge carriers present in a curing material is constant when conductivity is used as an in situ measurement technique to monitor changes in mobility. Ion mobility, time of flight (ITOF) measurements, which are described here, are an appropriate technique to isolate and measure particle mobility due to changes in the state of the material. The ITOF technique, coupled with the measurement of sigma, the ionic conductivity, allows one to measure separately changes in the mobility and the number of charge carriers due to curing or changes in temperature. This is possible since conductivity is the product of the number of charge carriers and their mobility. Length of pulse, strength of applied field, sensor geometry, and temperature/viscosity are examined to determine optimum parameters of measurement for both a simple non-curing system, and more complex, hydrogen-bonded epoxy.;The second focus of this thesis is our recently developed single stage in situ synthesis of hybrid membranes comprised of nanometer-sized metal and metal oxide particles in polyimides. The major goal is development of polymer based structural materials designed to achieve exceptional performance properties regarding gas permeability and gas separation selectivity, particularly in regard to their thickness, modulus, and strength to weight ratio. We investigate hybrid inorganic-polyimide films where the nanoparticle inorganic phases are of two types: (1) nanometer-sized rare earth (lanthanum, gadolinium and holmium) oxide molecular clusters and (2) nanometer-sized palladium and silver metal clusters. For the polymeric phase we used aromatic poly(amic acid)s-polyimides because of their strength and chemical and thermal stability.
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King, Shirley Anne. "Development of techniques for the isolation of a granulovirus from potato tuber moth, phthorimaea operculella (Zeller)." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1015202.
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Phthorimaea operculella, commonly known as the Potato Tuber Moth, is an economically important agricultural pest worldwide. The baculovirus, Phthorimaea operculella granulovirus (PhoGV) has been considered as a means of control alternative to chemical control because of its host specificity and harmless impact on other organisms and ecosystems. An isolate of PhoGV obtained from a South African PTM population would be beneficial in the production of a biopesticide, which is not yet available. An efficient and cost-effective rearing method would be advantageous for potential commercial production. Commercial table and seed potato plantations and storage facilities located in Patensie, Bathurst, Howick and Ivanhoe were surveyed for PTM infestations. Patensie was the only site where milky discoloured larvae were found, a potential symptom of PhoGV infection. TEM analysis revealed no virus in these samples. Since no virus was found in the field-collected samples, PTM insects were collected to initiate rearing in the laboratory. PTM was raised by three different methods in the laboratory. A cost/benefit analysis, survival rate, fertility and sex ratio were recorded for each rearing method. Rearing method one was deemed unsuccessful for efficient commercial rearing, as survival percentage and fertility were low. Rearing methods two and three had high survival rates and high fertility, and were efficient and less labour intensive than rearing method one. Rearing method three was the most productive technique, but for commercial production rearing method two was considered the most manageable and efficient. The sex ratio was 1:1 for all three cultures. The cost analysis revealed that rearing methods two and three were less expensive than rearing method one because less labour was required to monitor insects. The success of rearing PTM for 19 months will enable these cultures to be up-scaled to a large production facility for mass rearing. Virus was not found in the field surveys or in laboratory cultures, therefore chemical, temperature, humidity and carbon dioxide stressors were used in an attempt to initiate a baculoviral infection. Symptoms were exhibited in larvae subjected to chemical, temperature and humidity treatments, but these were confirmed by TEM analysis not to be a result of PhoGV infection. The success of rearing PTM in the laboratory suggests that the method could be used in the commercial rearing of the insects in a large mass-rearing facility. The data obtained from induction protocols have allowed for better understanding for future induction for PhoGV and other baculoviruses in other insect species. The failure to isolate a South African PhoGV strain for developing a biopesticide against PTM has motivated further studies in obtaining a baculovirus in order for South Africa to develop a commercial product against this pest.
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MacKenzie, Sabrena E. "Isolation and characterization of new fumonisins from Fusarium moniliforme NRRL 13616 and development of new analytical techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ36942.pdf.
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Chen, Xiao-Ming [Verfasser]. "Techniques of mapping and isolation of the pulmonary veins in patients with atrial fibrillation / Xiao-Ming Chen." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2013. http://d-nb.info/1035639343/34.
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Edwards, Victoria C. "Development of techniques for the isolation and characterisation of human monoclonal antibodies from hepatitis C virus infected individuals." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12774/.
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Infection with hepatitis C virus (HCV) is cleared spontaneously in only 20% of cases with the majority of individuals developing a chronic infection. This discrepancy in disease outcome is incompletely understood but current understanding of the immune response to HCV suggests that rapid induction of a broadly neutralising antibody (nAb) response leads to resolution of acute infection. The majority of nAb identified target the envelope glycoproteins, particularly E2, and most appear to inhibit binding of E2 to the cellular receptor CD81. Antibodies targeting other interactions, such as those with the receptor CLDN or the fusion determinant, are underrepresented in the repertoire of anti-HCV antibodies. However, the antibody discovery process may have been biased by the nature of the assays used. Therefore new assays are needed to enable the discovery and characterisation of antibodies in an unbiased manner. To facilitate this, a novel insect cell display library was developed for mapping antibody-binding epitopes. Cells expressing specific E2 mutants provided the necessary proof-of-principle that loss of antibody binding could be detected in this system before a library expressing randomly mutated E2 was developed. Sorting experiments demonstrated that single cells could be isolated and enriched based on loss of antibody binding. Secondly, a method for characterising the immunoglobulin (Ig) genes of HCV infected patients was developed; Ig genes were isolated from small numbers of B cells and the sequences analysed. Finally, a patient cohort was studied with a view to investigating the evolution of the antibody response during early infection. The unreliable nature of the samples prevented such analysis; however a DNA fingerprinting method of testing the origin and relatedness of serum samples was developed. This will improve the reliability of future studies. Together these methods provide a work model for the assessment of samples and the isolation and characterisation of antibodies.
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Momin, Vasim Rasul. "The Analysis of Antimicrobial Testing Vincetoxicum stocksii and Isolation of a Highly Active Compound Against Candida albicans by Using Various Different Techniques." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_theses/9.
Full textAbstract:
The purpose is to isolate a natural compound, which shows a high activity against Candida albicans, from plant, Vincetoxicum stocksii. Bio-Assay, Thin layer Chromatography, Column Chromatography, TLC bio Assay, and other extraction techniques are used in order to isolate the active compound. First, bio assay technique is carried out on the crude gum. Next, several flash chromatography columns are carried out in order to isolate the target compound, which has a Rf value of ~0.53 in 10:1 DCM/methanol solvent mixture. The TLC bioassay technique is also carried out in order to confirm the hypothesis that the target compound is indeed active.
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Parte, Yogesh. "Quelques techniques de couplage de modèles et de données." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/789/.
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Le couplage de modèles et de données est le fil conducteur de ce travail, qui comporte deux parties distinctes. La première partie présente des techniques d'évaluation des performances de produits d'isolation et la deuxième partie présente une contribution en optimisation multidisciplinaire. La première partie commence par décrire les limites des mesures classiques en laboratoire qui ne tiennent pas compte de la convection, du rayonnement et de changement de phase. L'inconvénient des mesures in situ est de fournir des performances fortement dépendantes des conditions météorologiques. A partir de séquences de données météorologiques représentatives du site et des mesures in situ, nous arrivons à estimer les performances intrinsèques du système d'isolation. Cet objectif a été atteint en considérant des techniques telles que les réseaux neuronale (globale assimilation process - GAP), les techniques de classification (predictive clustering - PClust) et nous avons considéré un modèle thermique mono-dimensionnel (SPEC) décrivant les phénomènes complexes en présence. Les résultats numériques obtenus, sur des mesures in situ, montrent la stabilité des résultats par rapport aux conditions météorologique. Dans la deuxième partie, une nouvelle méthode intitulée DIVE (Disciplinary Interaction Variable Elimination) est introduite. On a montré que DIVE est une généralisation de la méthode de région de confiance et présente de nombreux avantages par rapport aux méthodes d'optimisation multidisciplinaire (MDO) connues : une meilleure précision de la solution des équations d'état, un cadre adéquat pour la gestion des méta modèles. En plus, la méthode DIVE peut être vue comme une généralisation des méthodes de MDO classiquesCoupling of models and data is the central theme of this work, which has two distinct parts. The first part presents techniques to estimate performance of insulation products and the second part presents a contribution in multidisciplinary optimization. The first part begins by describing limitations of conventional laboratory measurements which do not account for the effect of convection, radiation and phase change on insulation product. The drawback of in situ measurements is that the measured insulation performance strongly depends on meteorological conditions. From the sequences of characteristic meteorological data of the site and in situ measurements, objective is to estimate intrinsic performance of the insulation system. The goal has been achieved using techniques such as neural networks (global assimilation process - GAP), classification technique (predictive clustering - PClust) and using one dimensional heat transfer models (SPEC) describing the complex phenomena present. Numerical results obtained using in situ measurements are shown to be independent of meteorological conditions. In the second part, a new method named DIVE (Disciplinary Interaction Variable Elimination) is introduced. It is shown that DIVE is a generalization of the trust region method and presents number of advantages compared to existing multidisciplinary optimization (MDO) methods: better accuracy in the solution of the state equations, a framework for meta model management. In addition, DIVE method can be considered as a generalization of existing MDO methods
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Chang, Yu-Wei. "Isolation and characterization of protein fractions from chickpea («Cicer arietinum» L.) and oat («Avena sativa» L.) seeds using proteomic techniques." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95049.
Full textAbstract:
Chickpea (Cicer arietinum L.) and oat (Avena sativa L.) seeds are important sources of protein ingredients with potential nutritional, functional and bioactive properties. Protein fractions were prepared from chickpea and oat using sequential extractions with distilled water (albumins), NaCl solution (globulins) and NaOH solution (glutelins), respectively. Molecular characteristics of individual protein fractions were investigated using polyacrylamide gel electrophoresis (Native- and SDS-PAGE, and 2-DGE) in combination with reversed-phase high performance liquid chromatography (RP-HPLC). Tryptic peptide sequences were identified using proteomic techniques including 1D trypsin in-gel digestion, liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) analysis and Mascot MS/MS ion search. Sequence similarity and potential bioactivity of proteins were examined using BLAST and BIOPEP analysis, respectively. Native-PAGE results showed chickpea and oat globulin fractions (C-Gb and O-Gb) contained proteins corresponding to legumin (11S) and avenalin (12S), respectively. SDS-PAGE revealed that chickpea albumin and globulin fractions (C-Ab and C-Gb) showed protein bands with MWs related to legumin (11S) and pea vicilin (7S) while chickpea glutelin fraction (C-Gt) showed protein bands with MWs related to rice glutelin; oat protein fractions (O-Ab, O-Gb and O-Gt) showed protein bands with MWs related to oat 12S globulin (avenalin). α- and β-subunits of globulin and glutelin fractions from chickpea and oat were identified with estimated MWs ranging from 31 to 45 kDa and from 21 to 31 kDa, respectively. In vitro chickpea albumin, globulin and glutelin hydrolysates showed DH of 22.8%, 28.6% and 28.8%, respectively; SDS-PAGE revealed that legumin α- and β-subunits from chickpea globulin fraction (C-Gb) were hydrolyzed. The identified tryptic peptides from chickpea and oat protein fractions showed sequence homology that corresponded to chickpea lLes semences du pois chiche (Cicer arietinum L.) et de l'avoine (Avena sativa L.) sont d'importantes sources d'ingrédients protéiques dont les propriétés nutritionnelles, fonctionnelles et bioactives démontrent un grand potentiel. Les fractions protéiques ont été préparées à partir du pois chiche et de l'avoine par extraction séquentielle avec de l'eau distillée (albumine), une solution de NaCl (globuline) et une solution de NaOH (glutelines), respectivement. Les caractéristiques moléculaires des fractions de protéines individuelles ont été examinées par électrophorèse en gel de polyacrylamide (non dénaturante et SDS-PAGE, et 2-DGE) en combinaison avec la chromatographie en phase liquide à haute performance en phase inversée. Les séquences de peptides tryptiques ont été identifiées par des techniques protéomiques telles que la digestion de trypsine en gel unidimensionnelle, l'analyse chromatographique en phase liquide couplée à la spectrométrie de masse en tandem avec ionisation de type électrospray (LC-ESI-MS/MS), et la recherche d'ions MS/MS (Mascot). Les similarités séquentielles et la bioactivité potentielle des protéines ont été examinées sous analyse par BLAST et BIOPEP, respectivement. Les résultats de l'électrophorèse non dénaturante en gel de polyacrylamide démontrent que les fractions de globulines du pois chiche et d'avoine (C-Gb et O-Gb) contiennent des protéines correspondant aux légumines (11S) et avenaline (12S), respectivement. La SDS-PAGE révèle que les fractions d'albumine et de globuline de pois chiche (C-Ab et C-Gb) montrent des bandes protéiques ayant des poids moléculaires reliés à la légumine (11S) et le viciline de pois (7S) alors que la fraction de glutéline de pois chiche (C-Gt) montre des bandes protéiques avec des poids moléculaires reliés à la glutéline de riz; les fractions protéiques d'avoine (O-Ab, O-Gb et O-Gt) montrent de bandes protéiques avec des poids moléculaire
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Salauddin, Hasan Shahariar. "Development of techniques for quantitative biofilm assay and isolation and characterization of an E. Coli gene involved in biofilm maturation." Thesis, Heriot-Watt University, 2008. http://hdl.handle.net/10399/2034.
Full textAbstract:
In their natural habitat bacteria predominantly exist as biofilms in which bacteria differ physiologically and metabolically from free-living cells. The aim of the study was to identify and characterize genes that are involved in biofilm maturation. The crystal violet (CV) assay is widely used to identify early stage biofilm mutants. However, it is not sufficiently sensitive to isolate late stage mutants that fail to develop mature biofilms. Using tetrazolium salt XTT (sodium 3'-{ l-[(phenylamino)-carbonyl]-3,4tetrazolium}- bis (4- methoxy-6-nitro) benzenesulfonic acid hydrate) this study therefore developed a more sensitive assay, named the XTT assay, to identify smaller changes in the quantity of biofilm. Using a combination of the CV and the XTT assays, a pool of transposon mediated mutant cells was screened and four genes (yhjN, adiA, bglX and glpX) were identified as potentially being involved in biofilm maturation. glpX was selected for further study. GlpX is a largely uncharacterised protein that had been shown to have FBPase activity in vitro. FBPase activity is required for the synthesis of colanic acid, a polysaccharide previously shown to playa key role in the development of the three-dimensional structure of the fully formed biofilm. The findings of this study 4 indicate that glpX-encoded FBPase activity is involved in colanic acid biosy~thesis in E. coli. A preliminary molecular analysis was made of the expression of glpX.
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Wu, Shumei Jocelyn. "Immunochemical techniques for the detection, isolation and characterization of connective tissue growth factor in diabetic urine and peritoneal dialysis fluid." Thesis, King's College London (University of London), 2012. https://kclpure.kcl.ac.uk/portal/en/theses/immunochemical-techniques-for-the-detection-isolation-and-characterization-of-connective-tissue-growth-factor-in-diabetic-urine-and-peritoneal-dialysis-fluid(c1f3c279-c133-42fa-a733-005deb10ba13).html.
Full textAbstract:
Connective tissue growth factor (CTGF) has been implicated in the pathogenesis of diabetic nephropathy and has been proposed as a possible specific biomarker for the early detection of fibrosis. CTGF is reported to be a 349-amino acid cysteine-rich, heparin binding monomeric polypeptide that is secreted as a 36-38 kDa protein. To date, the natural form of CTGF has not been successfully purified from clinical samples. Commercial test kits for detecting CTGF by ELISA utilize antibodies raised against recombinant human (rh) CTGF. In the present study, assessment of specific analytical methods for the reliable detection of naturally occurring CTGF has been deployed. In order to achieve this, a peptide sequence to CTGF was synthesized and an antibody raised against this peptide. This antibody was characterized using novel chemistry to improve the specificity of the final assay. The antibody raised against a unique peptide sequence in CTGF, and another to rhCTGF, were used, alongside a commercially available anti-rhCTGF antibody to detect this protein in diabetic urine and peritoneal dialysis fluid. The synthetic peptide antibody was also coupled to Sepharose 4B for the purification of CTGF from clinical samples. ELISA performed on the diabetic urine and peritoneal dialysis fluid showed that the response of the antibody against the synthetic peptide was the highest when compared to the rhCTGF and commercial antibodies. Five peritoneal dialysis fluid and five diabetic urine samples were assayed for CTGF. Diabetic urine was found to be a richer source of CTGF. 2-dimemsional electrophoresis and Western blot analyses on the peritoneal dialysis fluid showed various immunoreactive species to the synthetic peptide antibody at isoelectric point 8.0. It can be concluded that these immunoreactive species may be CTGF bound to other proteins or CTGF complexes that have been formed from the oxidation of the cysteine residues.
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Kadeer, Zibirnisa [Verfasser], Heinz D. [Gutachter] Osiewacz, and Hermann [Gutachter] Schägger. "Development of native electrophoretic techniques for the isolation and characterization of mitochondrial complexes / Zibirnisa Kadeer ; Gutachter: Heinz D. Osiewacz, Hermann Schägger." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2013. http://d-nb.info/1119247454/34.
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Momin, Vasim. "The analysis of antimicrobial testing Vincetoxicum stocksii and isolation of a highly active compound against Candida albicans by using various different techniques." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-04242008-132516/.
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Thesis (M.S.)--Georgia State University, 2008.Title from file title page. Keith Pascoe, committee chair; Alfons Baumstark, Jerry Smith, Davon Kennedy, committee members. Electronic text (46 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed July 8, 2008. Includes bibliographical references (p. 45-46).
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Bafor, Enitome E. "Isolation, identification and pharmacological evaluation of the uterine actives of Ficus exasperata Vahl (Moraceae) and the development and application of metabolomic techniques in drug discovery." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24309.
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In the search for new, safe and efficacious uterine active agents, the plant Ficus exasperata was subjected to phytochemical screening and pharmacological analysis. Ethyl acetate and methanolic leaf extracts of F. exasperata were fractionated and purified by a series of chromatographic techniques. The isolation process was guided by in vitro functional uterine assays involving the use of C57Bl/6 female mice. Identification of the active chemical constituents was performed by several spectroscopic techniques which included 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). The uterine effects of these compounds were investigated on lidocaine-induced, spontaneous, oxytocin-induced and high KCl-induced contractions using isolated uterine segments of non-pregnant female mice. The activity of different compounds on the amplitude (maximum tension above basal force) and frequency of uterine contractions were simultaneously measured and then statistically analysed. The structure-activity relationships were also examined where possible. These studies led to the identification of some new phytochemical derivatives. Pharmacological assays revealed the presence of both uterine stimulatory and inhibitory constituents. The new pheophytin/pheophorbide derivatives, flavonoids, fatty acids and glycerol derivatives significantly reduced the frequency and amplitude of uterine contraction, while KCl salt, pyrimidine and pheophorbide-b derivatives significantly augmented both spontaneous and agonist-induced contractions. This study has demonstrated that F. exasperata generates secondary metabolites which have proven effective in the significant inhibition of uterine contractions and thus a potential source of new tocolytic agents. Additionally, uterine stimulatory constituents were also generated some of which may be potential drugs for contraception and/or labour facilitation. Lead compounds generated from this study are the pheophytin/pheophorbide derivatives, pyrimidine derivatives and flavonoid derivatives. The rather low yield of compounds frequently experienced in the course of bioassay-guided phytochemical screening has made it almost impossible to investigate the possible mechanism(s) of action of active fractions and/or compounds. This necessitated study into the development of high throughput analytical tools combining metabolomics and pharmacology in the investigation of the function of drugs. This study involved the application of liquid chromatography coupled to high resolution Fourier transform mass spectrometry (LC-HRFTMS) and proton NMR (1H-NMR) as analytical platforms in the determination of myometrial function. An initial study was performed to determine the success of the method and this was achieved by assessment of mouse myometrial metabolites altered in response to oxytocin and ritodrine. The myometrial tissues and bath fluids were extracted at the peak of activity and subjected to LC-HRFTMS analysis. The use of the bath fluids in this study was an innovative approach in sampling. The resulting data were preprocessed and analyzed via a pair-wise chemometric comparison model. Pathway analyses following metabolite identification confirmed previously known mechanism(s) thus validating the method while revealing new insights and creating knowledge-driven hypotheses for future research. This study therefore enabled the development of a technique which combines metabolomics with in vitro pharmacology for the rapid detection of compelling myometrial metabolites in drug function and was successfully applied in the determination of possible mechanism(s) of the active constituents of F. exasperata.
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Wirbel, Ducoulombier Laure. "Conception d'un nouveau système d'isolation par l'exterieur pour le bâtiment." Thesis, Ecole centrale de Lille, 2014. http://www.theses.fr/2014ECLI0013/document.
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En France, Le secteur du bâtiment représente 40% de la consommation énergétique et 25% des émissions de CO₂. Afin de réduire ces impacts, une nouvelle Réglementation Thermique 2012, est rentrée en application. Dans ce contexte, l’Ecole Centrale de Lille et l’entreprise Norpac ont choisi d’engager une thèse CIFRE dans le but de développer un nouveau système d’isolation thermique par l’extérieur pour le bâtiment. Le choix s’est porté sur l’utilisation de matériaux textiles pour composer ce système appelé « Isolpac », en partenariat avec les entreprises Dickson, PEG, et l’association CLUBTEX. Les travaux de recherche ont d’abord été consacrés à la caractérisation hygrothermique, mécanique et chimique des différents matériaux qui composent le nouveau panneau d’isolation afin de définir leur propriétés intrinsèques, de les comparer avec des matériaux classiques, et de pouvoir valider leur choix pour le nouveau système. Deux méthodes d’essais de vieillissement accéléré ont été appliquées aux toiles.Ensuite, un intérêt particulier a été porté sur l’équilibre hygrothermique du panneau, à travers une simulation dynamique sur le logiciel Wufi® réalisée suite à la caractérisation préalable. En outre, la réaction au feu des panneaux et des perspectives d’essais pour garantir les performances mécaniques ont été étudiées.Enfin, la recherche de techniques de fixation et d’assemblage des panneaux est présentée. Des essais de pose in situ à l’échelle 1 ont été réalisés. Les perspectives d’essais liés à la résistance mécanique et au feu du système sont présentées. Un projet de façade démonstratrice est décrit afin d’être le support d’une demande d’avis technique expérimental du CSTBIn France, the building industry represents 40% of the total energy consumption and 25% of the total carbon dioxide emissions. In the objective of decreasing those impacts, a new thermal regulation called “Réglementation Thermique 2012” (RT2012), has been applied. In that context, the Ecole Centrale de Lille and the company Norpac, have chosen to engage a CIFRE thesis in order to develop a new external thermal insulation system for buildings. It was chosen to use textile materials to compose that system called “Isolpac”, in partnership with Dickson, PEG and the CLUBTEX association. At first, the research work was devoted to the hygrothermal, mechanical and chemical characterisation of the different materials composing the new insulation panel, to define the intrinsic properties of different materials, to compare them with conventional materials, in order to validate the choice of materials for the new insulation system. Two accelerated ageing methods were applied on the fabrics.Then, a particular interest is focused on the hygrothermal equilibrium of the panel by using a dynamic simulation on the software Wufi® following the previous characterization. Moreover, a work on the fire reaction of the panel and on the perspectives of other tests needed to guarantee the mechanical strength was carried out.Finally, the search of fixation and assembling techniques for the panels is presented. Installation in situ at scale one were made. The perspectives of tests for qualifying the mechanical strength and the fire resistance are described. A project of a demonstrating façade is presented to be the support for a demand of an Experimental Technical Agreement of the CSTB
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Okpako, Larry Commander. "Investigation of selected Nigerian medicinal plants as a source of new antimalarial agents. Isolation of phytochemicals from some Nigerian medicinal plants using chromatographic techniques and their evaluation for antiplasmodial activity." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/6304.
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Malaria affects hundreds of millions of people worldwide and equally claims hundreds of thousands of lives each year. With the current spread of drug resistance to standard antimalarial drugs like chloroquine and the emergence of artemisinin-resistant parasites, new antimalarial drugs and formulations are urgently needed.
An ethnobotanical survey was carried out in this study in search of novel compounds with promising antiplasmodial activity. Using the ethnobotanical approach, a total of 61 plant species from 59 genera distributed in 34 plant families were found to be used traditionally for the treatment of malaria in Nigeria.
Biological evaluation of the plant¿s methanolic extracts was assessed using the parasite lactate dehydrogenase (pLDH) assay against the chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of Plasmodium falciparum. A total of five (5) plant species showed more potent antiplasmodial activities against the malaria parasites. These are Acanthospermum hispidum, Cassia occidentalis, Kaempferia aethiopica Prosopis africana and Physalis angulata with MIC values ranging between 7.815µg/ml to 31.25µg/ml (3D7 strain) and 15.63µg/ml to 62.50µg/ml (K1 strain) against the malaria parasites, respectively. Two plants, Prosopis africana (Leguminosae-mimosoideae) and Physalis angulata (Solanaceae) were selected for further study.
The phytochemical investigation of the active chloroform extracts of P. africana and P. angulata yielded several compounds with three known alkaloids, namely, prosopinine (I), prosopine (II) and acetamide (III). Their structures were confirmed by MS, 1D and 2D NMR spectroscopy. Compounds I, II and III have moderate in vitro antiplasmodial activity against the malaria parasites. Both chloroquine and artemether were used as standard control.Association of Commonwealth Universities and the Commonwealth Scholarship Commission in the UK (Commonwealth Scholarship Reference Number: NGCS-2005-259).
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Salah, Adham M. S. "Investigation of Integrated Decoupling Methods for MIMO Antenna Systems. Design, Modelling and Implementation of MIMO Antenna Systems for Different Spectrum Applications with High Port-to-Port Isolation Using Different Decoupling Techniques." Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18427.
Full textAbstract:
Multiple-Input-Multiple-Output (MIMO) antenna technology refers to an antenna with
multiple radiators at both transmitter and receiver ends. It is designed to increase the data rate in
wireless communication systems by achieving multiple channels occupying the same bandwidth
in a multipath environment. The main drawback associated with this technology is the coupling
between the radiating elements. A MIMO antenna system merely acts as an antenna array if the
coupling between the radiating elements is high. For this reason, strong decoupling between the
radiating elements should be achieved, in order to utilize the benefits of MIMO technology.
The main objectives of this thesis are to investigate and implement several printed MIMO
antenna geometries with integrated decoupling approaches for WLAN, WiMAX, and 5G
applications. The characteristics of MIMO antenna performance have been reported in terms of
scattering parameters, envelope correlation coefficient (ECC), total active reflection coefficient
(TARC), channel capacity loss (CCL), diversity gain (DG), antenna efficiency, antenna peak gain
and antenna radiation patterns.
Three new 2×2 MIMO array antennas are proposed, covering dual and multiple spectrum
bandwidths for WLAN (2.4/5.2/5.8 GHz) and WiMAX (3.5 GHz) applications. These designs
employ a combination of DGS and neutralization line methods to reduce the coupling caused by
the surface current in the ground plane and between the radiating antenna elements. The minimum
achieved isolation between the MIMO antennas is found to be better than 15 dB and in some
bands exceeds 30 dB. The matching impedance is improved and the correlation coefficient values
achieved for all three antennas are very low. In addition, the diversity gains over all spectrum
bands are very close to the ideal value (DG = 10 dB).
The forth proposed MIMO antenna is a compact dual-band MIMO antenna operating at
WLAN bands (2.4/5.2/5.8 GHz). The antenna structure consists of two concentric double square
rings radiating elements printed symmetrically. A new method is applied which combines the
defected ground structure (DGS) decoupling method with five parasitic elements to reduce the
coupling between the radiating antennas in the two required bands.
A metamaterial-based isolation enhancement structure is investigated in the fifth proposed
MIMO antenna design. This MIMO antenna consists of two dual-band arc-shaped radiating
elements working in WLAN and Sub-6 GHz 5th generation (5G) bands. The antenna placement
and orientation decoupling method is applied to improve the isolation in the second band while
four split-ring resonators (SRRs) are added between the radiating elements to enhance the
isolation in the first band.
All the designs presented in this thesis have been fabricated and measured, with the simulated
and measured results agreeing well in most cases.Higher Committee for Education Development in Iraq (HCED)
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Bell, Benjamin. "Advancing the application of analytical techniques in the biological chemistry of sporopollenin : towards novel plant physiological tracers in Quaternary palynology." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/advancing-the-application-of-analytical-techniques-in-the-biological-chemistry-of-sporopollenin-towards-novel-plant-physiological-tracers-in-quaternary-palynology(59605f2b-642a-4ea9-8921-4c926217e6f2).html.
Full textAbstract:
Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p <0.001) and summer precipitation (r2 = 0.63, p <0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p <0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p <0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction. Palynology, the study of organic microfossils, is an important tool for improving our understanding of past environments and landscapes. Palynology provides a wealth of information from which climatic and environmental conditions can be inferred. However, inferred climatic and environmental conditions are often open to interpretation. Assumptions made about past climate conditions from pollen assemblages often rely on qualitative understanding of modern-day vegetation distributions, rather than empirical relationships. Historic anthropogenic impact on the environment must also be inferred, and assessments made as to whether vegetation changes are a result of climate change or human impact. This study seeks to address some of the questions that arise through the interpretation of pollen assemblages, by establishing empirical relationships between the geochemistry of modern pollen and climate or environmental controls. It focuses on the pollen of the climatically sensitive montane conifer Cedrus atlantica, which is distributed across the mountains of Morocco and Algeria. The study investigates aspects of modern pollen geochemistry and morphology and finds a strong relationship between the stable carbon isotope composition of modern pollen and mean annual precipitation (r2 = 0.54, p <0.001) and summer precipitation (r2 = 0.63, p <0.0001). Furthermore, a stronger relationship exists with aridity measured using the self-calibrating Palmer Drought Severity Index (r2 = 0.86, p <0.0001), suggesting that the stable carbon isotope composition of Cedrus atlantica pollen is influenced by environmental moisture availability. The study also finds there is an increased abundance of ultraviolet absorbing compounds (UACs) in modern Cedrus atlantica pollen with increasing summer UV-B flux. This relationship was evident with samples growing in their native range (r2 = 0.84, p <0.0001), but not with samples from outside this range (r2 = 0.00, p = 0.99), suggesting a possible genetic influence. Lastly, the study finds that grain size of Cedrus atlantica pollen is highly variable within and between samples, and we rule out climatic control on pollen grain size. These results suggest that quantitative relationships can be established between the geochemistry of Cedrus atlantica pollen and environmental and climatic influences. Stable carbon isotope analysis of fossil pollen could be used as a proxy for reconstruction of summer moisture availability, while analysis of UACs in fossil pollen could be used as a proxy for the reconstruction of summer UV-B flux. These proxies will enhance our understanding of climatic and environmental change in Northwest Africa and will complement existing palynological techniques for environmental and climate reconstruction.
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Lubiana, Karoline Magalhães Ferreira. "Culturas como alternativa para elucidação de biodiversidade críptica do fitoplâncton: o caso das águas costeiras do estado de São Paulo." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-09042014-180843/.
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O fitoplâncton é composto por uma gama de organismos fotossintetizantes de diversas origens evolutivas. São os principais produtores primários dos oceanos embora sua biodiversidade seja muito pouco estudada, principalmente as frações do nano e picoplâncton. A composição florística dessas duas frações do fitoplâncton marinho é praticamente desconhecida nas águas brasileiras, entretanto diversos trabalhos ecológicos e oceanográficos relatam sua importância, pois são os mais abundantes nas regiões marinhas. O presente estudo teve como objetivo isolar espécies de microalgas, com ênfase nos fitoflagelados, a partir de amostras coletadas de Cananéia, Ubatuba e Santos, a fim de aumentar o conhecimento acerca da composição taxonômica desses organismos e permitir estudos futuros, envolvendo análises moleculares, ultraestruturais e fisiológicas. Para isso, foram usadas várias técnicas tradicionais de isolamento, como cultura mista, micropipetagem e diluições sucessivas, plaqueamento em ágar e diluição seriada. Foram isolados 49 cepas das classes Cyanophyceae, Trebouxiophyceae, Cryptophyceae, Bacillariophyceae, Prasinophyceae, Nephroselmidophyceae, Chrysophyceae e outros não identificados. Análises pigmentares foram realizadas em especial para o grupo das Cryptophyceae para confirmar a identificação em nível genérico. Vários dos táxons isolados representam novos registros para o estado de São Paulo e para a costa do Brasil. Os resultados do presente estudo são uma boa partida para a inclusão filogenética dos organismos isolados na costa do Brasil no contexto mundial, auxiliando a desvendar a biodiversidade críptica de espécies até o momento desconhecidas para as regiões estudadasPhytoplankton comprises a range of photosynthetic organisms with different evolutionary origins. They are the main primary producers in the oceans but its biodiversity is poorly studied, especially on the nano and picoplankton fractions. Although the floristic composition of these two fractions of the marine phytoplankton is virtually unknown in Brazilian waters, several studies have reported the oceanographic and ecological importance of these groups, which are the most abundant in marine environment. This study aimed to isolate microalgae species with emphasis on \"phytoflagellates\" from samples collected in Cananéia, Ubatuba and Santos in order to increase the knowledge about their taxonomic composition and allow future studies involving molecular, ultrastructural and physiological analysis. For this, several traditional single-cell isolation techniques were used such as enrichment culture, micropipette, agar plating and serial dilutions. There were isolated 49 strains of Cyanophyceae, Trebouxiophyceae, Cryptophyceae, Bacillariophyceae, Prasinophyceae, Nephroselmidophyceae, Chrysophyceae classes and others unidentified. Pigment analyzes were performed specially on Cryptophyceae group in order to confirm their identification at generic level. Several of the isolated taxa are new records for the state of São Paulo and the coast of Brazil. The findings of this study enable the phylogenetic inclusion of organisms isolated from the Brazilian coast in a world context, helping to unravel the cryptic biodiversity of organisms hitherto unknown for the studied regions
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Kachkouch, Salah. "Évaluation expérimentale et par simulation des performances thermiques de techniques passives appliquées aux toitures pour le rafraîchissement des bâtiments en climat chaud." Thesis, La Rochelle, 2018. http://www.theses.fr/2018LAROS021/document.
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Le bâtiment est l'un des secteurs les plus consommateurs d'énergie et producteurs de CO2 au monde. Au Maroc, ce secteur représente actuellement 33% de la consommation totale d’énergie à l'échelle nationale. Le nouveau règlement thermique au Maroc vise à introduire des pratiques éco énergétiques dans ce secteur pour réduire ces consommations. En effet, dans la région méditerranéenne, l’architecture du bâtiment a un impact primordial sur sa performance énergétique et thermique. Par ailleurs, l’intégration des techniques passives et l’utilisation des matériaux locaux pourraient réduire considérablement la consommation d’énergie dans le secteur du bâtiment. C’est dans ce contexte que se situe cette thèse de doctorat dont l’objectif est d’évaluer la capacité de rafraîchissement de quelques techniques passives pour la protection solaire des toitures et de montrer l’importance de l’utilisation des matériaux naturels locaux dans le climat chaud et semi-aride de Marrakech. En effet, trois techniques passives de rafraîchissement de l'air dans les bâtiments sont testées dans des conditions climatiques réelles dans la ville de Marrakech. Les techniques passives, à savoir la peinture blanche, l'ombrage et l'isolation thermique, sont appliquées sur les toits de trois cellules test métalliques placées à l’extérieur. Les performances thermiques de ces techniques sont évaluées simultanément via un monitoring de 29 jours d’été de quatre cellules test identiques, dont une cellule test de référence à toit nu (sans traitement). Ces cellules test ne représentent pas des bâtiments réels là où nous pouvons mener une étude approfondie. Pour cela, nous avons construit un bâtiment réel qui représente une salle de classe dans le milieu rural du Sud marocain, et ceci en utilisant des matériaux naturels et en intégrant des techniques passives dans la toiture. Les performances thermiques et énergétiques des mêmes techniques sont évaluées par le biais des simulations thermiques dynamiques sur l’outil TRNSYS ainsi qu’une étude expérimentaleThe building is one of the most energy-consuming and CO2-producing sectors in the world. Nowadays, this sector accounts for 33% of total energy consumption in Morocco. The new thermal regulation in Morocco aims to introduce eco-energy practices in this sector to reduce this consumption. Indeed, in the Mediterranean region, building architecture has a major impact on its energy and thermal performance. In addition, the integration of passive techniques and the use of local materials could significantly reduce energy consumption in the building sector. In this context where this thesis is located and whose objective is to evaluate the cooling capacity of some passive techniques for the solar protection of roofs and to show the importance of the use of local natural materials in the hot and semi-arid climate of Marrakech. Indeed, three passive cooling techniques are tested in real conditions in the Marrakech region. Passive techniques, namely white paint, shading and thermal insulation, are applied to the roofs of three outside test cells. The thermal performances of these techniques are evaluated simultaneously via a 29-day summer monitoring of four identical test cells, including a bare roof reference test cell (without treatment). Small scale test cells do not represent real buildings where an in-depth study can be conducted. To remedy this, we built a single-zone building that represents a classroom in rural region in southern Morocco, using natural materials and incorporating passive techniques into the roof. The thermal and energetic performances of the same techniques are evaluated by means of dynamic thermal simulations on TRNSYS as well as an experimental study
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Vrabelova, Daniela. "Evaluation of a high-yield technique for pancreatic islet isolation from deceased canine donors." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365099629.
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Domingues, Helena Gallicchio. "Detecção, isolamento e caracterização molecular parcial de virus respiratorio sincicial bovino (BRSV) em amostras de campo." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316624.
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Orientador: Clarice Weis ArnsTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-05T02:18:52Z (GMT). No. of bitstreams: 1 Domingues_HelenaGallicchio_D.pdf: 1037559 bytes, checksum: 5f1aa70035e934b591bffbdd05c647b9 (MD5) Previous issue date: 2005
Resumo: No presente estudo, técnicas para a detecção do vírus respiratório sincicial bovino, BRSV, visando ao diagnóstico e caracterização molecular deste patógeno, foram adaptadas e aplicadas em amostras coletadas de animais sem levar em consideração a presença de sinais e sintomas clínicos característicos de infecções causadas por esse agente. Foi coletado um total de 278 amostras de secreções nasais e fragmentos pulmonares de rebanhos bovinos provenientes dos estados de São Paulo e Rio Grande do Sul. Utilizando a técnica de RT-PCR detectou-se a presença de BRSV em sete amostras, duas de secreções nasais e cinco de fragmentos de pulmões. As amostras positivas foram submetidas ao isolamento viral e um novo isolado, denominado BRSV-108-BR, foi obtido após nove passagens em cultivos de células. Os fragmentos de 603 pb correspondentes ao segmento genômico da proteína G das amostras de BRSV em estudo, obtidos com a técnica de RT-PCR, foram submetidos à análise por enzimas de restrição-REA e ao seqüenciamento, visando sua caracterização molecular. Com a técnica de REA foram identificadas variações genéticas entre as amostras de BRSV detectadas, sugestivas de que duas amostras pertenciam ao subgrupo AB e cinco, ao subgrupo B de BRSV. Entretanto, a análise filogenética realizada pelo alinhamento das seqüências obtidas com seqüências disponíveis no GeneBank revelou que todas as amostras detectadas pertenciam ao subgrupo B. Com este estudo sugerimos que a técnica de REA possui utilidade limitada para classificação de BRSV em subgrupos, podendo ser utilizada como um instrumento prévio na caracterização das amostras, sendo, todavia, estritamente necessária uma análise baseada no seqüenciamento do gene da proteína G para caracterização de BRSV em subgrupos
Abstract: In this study techniques to detect the bovine respiratory syncytial virus (BRSV), aiming at the diagnosis and molecular characterization of this pathogen, where adapted and applied in samples collected from animals regardless of the presence of clinical signs and symptoms characteristic of infections caused by this agent. A total of 278 samples of nasal secretion and pulmonary fragments of bovine herds from the States of São Paulo and Rio Grande do Sul. By using the RT-PCR technique it was detected the presence of BRSV in seven samples, two of the nasal secretion samples, and five of the pulmonary fragments samples. The positive samples were submitted to viral isolation, and a new isolate named BRSV-108-BR was obtained after nine passages in cell cultivations. 603 pb fragments corresponding to the genomic segment of the G protein of the BRSV samples in study and obtained through the RT-PCR technique were submitted to restriction enzyme analysis (REA) and sequencing, aiming at their molecular characterization. With the REA technique, genetic variations were identified among the detected BRSV samples, suggesting that two samples belonged to the BSRV AB subgroup and five belonged to the BRSV B subgroup. However, phylogenetic analysis carried out by sequence alignment obtained with sequences available at the GeneBank revealed that all samples detected belonged to subgroup B. With this study we suggest that the REA technique to classify BRSV subgroups has a limited usefulness, serving only as a prior instrument to characterize the samples. Nevertheless, a subsequent analysis based on G protein sequencing is extremely necessary to characterize samples in one of the different BRSV existing subgroups
Doutorado
Genetica Animal e Evolução
Doutor em Genetica e Biologia Molecular
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CORNIBERT, LAURENT. "Isolations dielectriques pour circuits microelectroniques de puissance basees sur des techniques de fusion localisee." Toulouse 3, 1999. http://www.theses.fr/1999TOU30129.
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Le contenu de ce memoire porte sur la mise en uvre, au moyen de recuits thermiques rapides infrarouges, de deux procedes technologiques dedies a l'isolation electrique dans les circuits integres de puissance: la thermomigration d'aluminium en phase liquide et le procede lego (epitaxie laterale sur oxyde). Les procedes d'isolation les plus repandus sont tout d'abord presentes et les limites en sont definies : difficultes de realisation de couches d'oxyde enterrees localisees dans le cas de l'isolation par oxyde ou de l'isolation mixte (oxyde et jonction) et budgets thermiques importants dans le cas de l'isolation par jonction de composants verticaux. Un procede de realisation de couche soi localisees, base sur la recristallisation du polysilicium en phase liquide a partir d'un germe monocristallin (lego) est ensuite presente. Un modele mathematique permettant d'evaluer l'influence des parametres de la structure soi est propose, puis etaye par des donnees experimentales. Enfin, un procede de realisation rapide de caissons d'isolation par jonction est etudie. Dans cette methode, le deplacement d'un alliage al-si liquide, sous l'effet d'un gradient thermique (thermomigration d'aluminium), permet de doper localement le silicium. Les principaux mecanismes physiques de la thermomigration d'aluminium sont decrits, et les parametres influencant la stabilite du phenomene sont identifies. Les performances, en termes d'isolation electrique, des structures ainsi realisees sont en particulier examinees.
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Moore, William N. "Supercritical fluid extraction as a sample preparation technique for the isolation of polar pharmaceutical compounds." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10052007-143203/.
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Gaylard, Robin Peter. "Perspectives on isolation: the relation of narrative technique to theme in selected works by Joseph Conrad." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001833.
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" ... the central concern of this thesis, which is to investigate the ways in which Conrad uses a particular technique (that of the first-person narrator ) to focus our attention, to secure our involvement, and to direct our sympathies. At the same time I wish to examine the extent to which the central themes or concerns of each work derive from the interaction between the narrator and the man whose experience he confronts, from "the challenging interplay of two frames of reference, two schemes of values, two sets of attitudes" that the use of a dramatized narrator makes possible." (Introd., p. 5)Adobe Acrobat 9.53 Paper Capture Plug-in
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Miranda, Lourdes das Neves. "Colonização por Candida em indivíduos com candidemia." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5134/tde-04042008-153349/.
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Nas duas últimas décadas, várias espécies de Candida têm surgido como importantes patógenos hospitalares, no mundo e no Brasil. A identificação da origem da infecção tem importância na definição de estratégias de prevenção e controle. As estratégias para a prevenção de candidíase endógena podem focar, parcialmente, em métodos para redução da colonização de mucosas, por exemplo, a restrição ao uso de antibióticos de largo espectro. Entretanto, nos casos nos quais está envolvida uma fonte exógena, um expressivo reforço, na melhoria da qualidade das práticas de assistência à saúde, é prioritário para prevenção da transmissão. O objetivo deste estudo foi avaliar diferentes sítios de colonização por Candida como potenciais fontes de candidemia. O estudo foi desenvolvido em 3 hospitais no Brasil: Instituto Central do Hospital das Clínicas da Faculdade de Medicina de São Paulo, hospital universitário de nível terciário de complexidade, com mil leitos; o Instituto de Infectologia Emílio Ribas, um hospital com 200 leitos, referência para todo o Estado de São Paulo; e o Hospital Geral de Itapecerica da Serra, hospital de cuidados secundários da Grande São Paulo. Foram incluídos no estudo os pacientes com isolamento de Candida em hemocultura obtida de veia periférica após 48 horas de admissão hospitalar. As culturas de vigilância para Candida foram colhidas dos seguintes sítios: urina, reto, cavidade oral, pele (virilha e axila), pele ao redor do cateter e ponta de cateter caso disponível. A tipagem molecular foi realizada quando a mesma espécie de Candida (C. albicans, C. parapsilosis, C. tropicalis and C. glabrata) foi isolada no sangue e nos sítios de vigilância do mesmo paciente. A eletroforese em campo pulsado foi realizada para os isolados de C. albicans, C. parapsilosis e C. glabrata. A amplificação de segmentos polimórficos do DNA foi realizada para C. albicans e C. tropicalis. No total 63 pacientes consecutivos com candidemia foram incluídos no estudo no período de maio de 2004 a outubro de 2005. C. albicans foi isolada em 42% das hemoculturas, C. parapsilosis em 35%, C. tropicalis em 16%, C. guilliermondii, C. krusei, C. glabrata, e C. holmii, em 2% cada uma. Unicamente seis dos 10 isolados de ponta de cateter apresentaram perfil eletroforético idêntico aos isolados de C. parapsilosis do sangue. Os isolados de C. albicans do sangue e de culturas de vigilância do trato gastrintestinal correspondentes, oriundos de 12 pacientes, apresentaram genótipos idênticos. Os resultados sugerem que a colonização do trato gastrintestinal é a provável fonte de candidemia por C. albicans e que a candidemia por C. parasilosis é de origem exógena.In the last two decades, Candida spp. have emerged as important nosocomial pathogens in the world and in Brazil. The identification of the source of infection is important in approaching prevention and control strategies. Strategies for the prevention of endogenous candidiasis may focus, to a certain extent, on methods for reducing mucosal colonization, for example limitation use of wide-spectrum antibiotics. However, in cases in which an exogenous source is involved, the aggressive reinforcement of adequate healthcare practices is mandatory to prevent transmission. The objective of this study was to evaluate different Candida colonization sites as potential sources for Candida fungemia. The study was done in 3 hospitals in Brazil: the Central Institute of Hospital das Clinicas, a 1000-bed tertiary-care hospital affiliated to the University of São Paulo; the Institute Emilio Ribas, a 200-bed infectious diseases hospital, reference for all the state of São Paulo; and the General Hospital of Itapecerica da Serra, a secondary-care community hospital located in area of the greater São Paulo. The patients with a positive blood culture for Candida, collected from a peripheral vein, were included in the study if they had to be hospitalized for 48 hours or more before candidemia. The following surveillance cultures for Candida were collected from: urine, rectum, oropharynx, skin (groin and axilla), skin around the catheter and catheter tip if available. Molecular typing was performed when the same species of Candida (C. albicans, C. parapsilosis, C. tropicalis and C. glabrata) was isolated from the blood and from surveillance sites of a single patient. Pulsed-field gel electrophoresis was performed for C. albicans, C. parapsilosis and C. glabrata isolates. Randomly amplified polymorphic DNA was performed for C. albicans and C. tropicalis. A total of 63 consecutive patients with candidemia were included in the period from May 2004 to October 2005. C. albicans comprised 42% of the blood isolates, C. parapsilosis 35%, C. tropicalis 16%, C. guilliermondii, C. krusei, C. glabrata, and C. holmii, 2% each. Six of the 10 isolates from catheter tips presented identical electrophoretic profiles to corresponding C. parapsilosis blood cultures and no other surveillance sites were related. C. albicans isolates from blood and from corresponding gastrointestinal surveillance sites from 12 patients presented identical genotypes. In conclusion, our results suggest that tract gastrointestinal colonization is the probable source of C. albicans candidemia and that C. parapsilosis candidemia is not endogenous.
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Pascali, Marina Vasiliki. "Techniques for isolating human chromosomal DNA surrounding an integrated HSV-1 thymidine kinase gene." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59858.
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The KT cell line was developed to study the nature of spontaneous mutations in eukaryotic cells. The plasmid pSV2neoKT, containing the herpes simplex virus type 1 (HSV-1) thymidine kinase (tk) gene, was used to transfect human AK143tk$ sp-$ cells. A $tk sp+$, G418$ sp{ rm R}$ clone, containing a single integrated copy of the plasmid, was isolated and expanded to form the KT cell line.Plasmid rescue was designed to recover a 15kb autonomously replicating plasmid containing the integrated pSV2neoKT sequences and the cellular DNA surrounding the integration site. Concurrently, a second method was pursued to clone each junction site separately as two smaller fragments using the cloning vectors pUC119 or pBR322.
Three variations of the polymerase chain reaction (PCR) were also used to amplify the cellular DNA flanking the integration site: anchored PCR, single-specific-primer PCR and inverse PCR.
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Catalano, Rob D. "Isolation and characterisation of a haploid expressed testis-specific cDNA in mouse using the differential display technique." Thesis, University of Warwick, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264903.
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Herriott, Deborah. "The effects of isolation technique, substrata and pyrazole on cytochrome P450 enzymes in cultured male rat hepatocytes." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395973.
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Pacitti, Andrew P. "Isolation of Mesenchymal Stem Cells Derived from Adult Bone Marrow and Umbilical Cord Blood and Their Potential to Differentiate into Osteoblasts." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/728.
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The demand for treatment strategies of musculoskeletal tissues is continuously growing, especially considering the increasing number of elderly people with degenerative diseases of the skeletal system. Despite major strides in the field of bone regenerative medicine during the years, current therapies, such as bone grafts, still have several limitations. Multipotent stem cells, such as mesenchymal stem cells (MSCs) are promising candidates for tissue repair because of their differentiation potential and their capacity to undergo extensive replication. However, isolating a homogeneous population of MSCs from multiple sources is an area that needs to be addressed. Also, the knowledge regarding the mechanisms and pathways that lead to the final osteogenic differentiation is still scarce. The following research is a feasibility study on a new isolation technique developed by our lab. The major focus of the research will be the isolation and characterization of mesenchymal stem cells from both adult bone marrow and umbilical cord blood using a novel isolation method based on immunodepletion. Furthermore we will look at the potential of these isolated MSCs to differentiate into mature, bone producing osteoblasts. The results of the studies showed that our novel isolation method allowed proliferation of a homogeneous MSC population. Our irnrnunodepleted MSCs were 99% double positive for antibodies CD44 and CD105 which are highly specific for multipotent MSCs while cells isolated using the plastic adherence method were only 43% double positive for the two MSC-specific markers. Homogeneous MSCs were derived from both adult bone marrow and umbilical cord blood using our isolation method. Utilizing the techniques of confocal microscopy, von Kossa staining, and RTPCR we also show that MSCs, upon stimulation with osteogenic supplements, differentiate into osteoblasts capable of being used for bone tissue engineering applications.
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Bridgett, Richard James. "The application of chromatographic techniques and behavioural bioassays towards isolating and characterising honey bee phagostimulants." Thesis, Keele University, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.716364.
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Numbers of honey bees (Apis mellifera) have fallen over recent years, potentially (in part) due to weaker colonies being more susceptible to disease, and consequently collapse. To boost colony strength and population, high-protein artificial or supplemental diets can be provided for bee consumption. This thesis investigated whether an integrated use of chromatographic techniques, including GC-MS, HPLC, LC-MS, and countercurrent chromatography (CCC), with bioassays conducted using bee colonies (in a process of bio-guided fractionation), can aid the isolation and characterisation of naturally occurring feeding stimulants (phagostimulants) within pollens. Adding these phagostimulants to such diets could increase diet consumption. A novel method for effectively conducting multiple-choice (more than two choices) bioassays, which assess diet palatability using a reduced number of colonies, has been developed. This method, is thought to be the first direct comparison of the increased feeding stimulation provided by added solvent extracts (that vary in polarity) of pollen to artificial diets. Using this method, experimental data obtained suggests that more polar extracts may provide increased stimulation over less polar extracts. An original application of CCC then facilitated some large-scale fractionation of the pollen extract material contained in methanol extracts of pollen. Collected fractions had their stimulatory activity tested, and obtained results suggest that the majority of the extractable material (c.a. 75% by mass and including the sugars) from foraged pollens provide little feeding stimulation to bees. However, increased stimulation was delivered by a complex (> 100 compounds) fraction believed to contain fatty acids and sterols, as well as other unknowns. Finally, a preliminary chemometrics study was carried out to reveal compounds that are present in either distinct or equivalent abundances in the chemical profiles of multiple pollen species, and the obtained active fraction. Through this, the potential future use of chemometics to aid phagostimulant characterisation has been evaluated.