Tesis: "Isolation methods"

1

McKinnell, Robert James. "Active isolation of vibration." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306465.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Pannifer, Susan. "Novel methods for the isolation and purification of exoglycosidases." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/26600.

Texto completo

Resumen

A number of exoglycosidases have been prepared from bacterial and plant sources using established methods for the separation of enzymes, in conjunction with certain novel purification systems hitherto not described in the literature for these enzymes. The enzyme, beta-galactosidase from E. coli has been prepared using previously described methods of phase separation and ion-exchange chromatography. As a final step in this purification, the use of a new hydroxyl-rich chromatographic support for the isolation of high-grade enzyme suitable for use in enzyme immunoassays was investigated. Methods have also been studied for the recovery of alpha-mannosidase as a by-product of the procedure used for the extraction of urease from jack bean (Canavalia ensiformis). The inclusion of a novel step involving the use of hydrophobic-interaction chromatography on Phenyl-Sepharose led to excellent recoveries of enzyme suitable for commercial use. Studies on a second glycosidase, beta-N-acetylhexosaminidase, from the same source (jack bean) paved the way for an adaptation of existing purification methods to provide increased yields and an improved quality of enzyme. Since the research unit in which this work was performed is associated with commercial organizations responsible for the preparation and marketing of biologically active products, it is important that the methods of purification described in this thesis are compatible with the requirements for largescale purification.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

楊謹鴻 and Kim-fong Roseline Yong. "Exploring hikikomori: a mixed methods qualitative research." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41712146.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Yong, Kim-fong Roseline. "Exploring hikikomori a mixed methods qualitative research /." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41712146.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Xu, Yue, of Western Sydney Hawkesbury University, of Science Technology and Agriculture Faculty, and School of Food Science. "Isolation and characterization of components from whey." THESIS_FSTA_SFS_Xu_Y.xml, 1996. http://handle.uws.edu.au:8081/1959.7/248.

Texto completo

Resumen

The structure, functionality, isolation methods and applications of whey components, particularly the proteins and lactose, have been extensively studied. These studies have had a great impact on the food industry where whey components are increasingly being used as food ingredients. Two generations of whey protein product, namely Lactalbumin, produced by heat-induced precipitation, and Whey Protein Concentration/ Isloate, produced by ultrafiltration/ ion exchange chromatography, have been commercialised. Crystalline lactose in the food and pharmaceutical grades is also being produced. Recently, research activities in whey fractionation have shifted to the isolation of the minor components. This thesis is aimed at developing a Total Whey Utilization strategy by which the several components of the whey stream would be completely recovered by fractionation, resulting in little or no residue to be disposed of in the wastewater stream. Therefore, this study was initially dedicated to the development of novel separation methods which would be suitable for the Total Whey Utilization process. The development of those techniques revealed some previously unknown feature of whey components. The mechanisms of the separation methods have been also investigated. Although crystallization is an efficient method for fractionation or purification, its disadvantage is that the mother liquor is a wastewater containing high salt and BOD (Biological Oxygen Demand). The chromatographic method has been investigated in this work to separate the mother liquor or permeate into lactose and mineral fractions such that a goal of this thesis, namely a 'clean' water stream after processing whey, can be finally achieved. These studies have focused on the effect of resin type, salt form of the resin and the operating conditions on the separation of the lactose and mineral fraction. Doctor of Philosophy (PhD)

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Rattfält, Linda. "A comparative study of two structural methods for fault isolation analysis." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2222.

Texto completo

Resumen

Technical systems of today are often complex and integrated. If a fault occurs, the consequences can be disastrous both for the system itself and its surroundings. To maintain the operation and the security it is necessary to have a surveillance system which can detect a fault in an early stage.In this thesis two structural methods for fault isolation analysis are discussed. The result from the studied algorithms shows what fault isolation properties a diagnostic model is expected to have. If the isolability is not good enough, it also gives information on where further modelling needs to be done. To base a comparison of the two structural analysis algorithms on, four criteria are defined concerning for example realizability of residuals and time complexity. One interesting part of the methods is how dynamic models are handled. It is shown how differential constraints can end up in differential cycles which implies calculatory problems and what effects structural differentiation has on a system. The algorithms have been tested on an application from the research training network DAMADICS. The result shows how different types of input models in this case give the same result.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Reiman, Lucy. "Development of isolation and identification methods for emerging species of Campylobacteraceae." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439655.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Mead, Kenneth Ross. "Expedient methods for patient isolation during natural or manmade epidemic response." Oklahoma City : [s.n.], 2008.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Hagardson, Karin. "Comparison of DNA isolation methods to detect Leishmania parasites in blood samples." Thesis, Uppsala University, Department of Medical Biochemistry and Microbiology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7014.

Texto completo

Resumen

Leishmaniasis is a disease affecting more than 12 million people worldwide. It is caused by the protozoan parasite Leishmania, which is transmitted to humans and dog hosts through bites of infected sand flies belonging to genus Phlebotomine. Several studies have shown Polymerase Chain Reaction (PCR) to be effective for the diagnosis of VL in clinical samples compared to the classical methods. The aims of this study were first to compare four different sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and furthermore to find a method that is sensitive, rapid, cost benefit, simple and easy to perform. Two preparation methods were compared for the isolation of leukocytes (with Ficoll and Tris –EDTA buffer) and two DNA isolation methods (with Proteinase K and QIAgen kit). From the methods that were compared, lysis of erythrocytes with TE and the QIAgen kit seems to be the most suitable to use.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Atty, Nicholas Martin. "Isolation of cloned DNA sequences encoding wheat ribosomal proteins by immunological methods." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329973.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Ward, David. "Scalable separation methods for the isolation of monosaccharides in a biorefinery context." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10057345/.

Texto completo

Resumen

Biorefineries allow for the sustainable production of higher value products from biomass. In addition to bioethanol, they can produce added value chemicals and pharmaceutical intermediates from isolated component compounds such as sugars. Sugar beet pulp (SBP) is a high volume, low value by-product from sugar beet processing with a low lignin and a high carbohydrate content, making it an attractive biomass feedstock for biorefinery processing. The pectin fraction of SBP can be isolated via steam explosion, which, after complete acid hydrolysis, gives a hydrolysate rich in monosaccharides: primarily L-arabinose (Ara) and D-galacturonic acid (GA), with some D-galactose (Gal) and L-rhamnose (Rha). Isolation of these sugars is therefore a critical step in realising an integrated, whole crop biorefinery. Currently, little work has been reported on the separation and utilisation of SBP hydrolysates. The aim of this thesis is to establish novel, scalable separation processes for the isolation of the component monosaccharides from crude hydrolysed sugar beet pulp pectin. Centrifugal partition chromatography (CPC) is a liquid-liquid separation technique with no solid stationary phase and offers an alternative to traditional resin-based chromatographic techniques. As such it can more easily cope with crude feedstreams such as hydrolysates. Hydrophilic ethanol : ammonium sulphate two-phase systems were examined based on monosaccharide partition coefficients and phase settling times. An ethanol : aqueous ammonium sulphate (300 g L-1 ) (0.8:1.8 v:v) system was chosen for CPC separations of the crude SBP hydrolysate and was shown to be capable of removing the coloured contaminants and isolating three sugar fractions in a single step: Rha, Ara and Gal, and GA. The separation was optimised and the throughput was increased by maximising the sample loading. Operation in an elution-extrusion mode allowed for reproducible separations in 100 min without additional column regeneration. The process was scaled up from a 250 to a 950 mL column providing a final throughput of 1.9 gmonosaccharides L -1 column h -1 using the crude SBP. The following purities and recoveries of the three main fractions were achieved: Rha at 92% purityand 93% recovery; Ara at 84% purity and 97% recovery; and GA at 96% purity and 95% recovery. Simulated moving bed (SMB) allows for continuous chromatographic separations using multiple columns, improving separation performance and throughputs. Isolation of Ara from the neutral sugars Gal and Rha was performed with resins and conditions screened on single columns leading to the selection of a Dowex 50W X8 resin in the Ca2+ form. SMB separation using 8 columns was performed in the 4-zone and 3-zone setups and achieved 94% purity with 99% recovery at a throughput of 4.6 gmonosaccharides L -1 column h -1 with a synthetic mixture of the neutral sugars (Ara, Gal and Rha). However, equivalent separations could not be achieved using the crude SBP hydrolysate which needed pretreatment before SMB. Decolourisation with activated carbon was able to remove 97% of the coloured contaminants with sugar losses of 15% (w/w) in a batch process demonstrated to 50 mL scale. Anion exchange chromatography using a Dowex 1x8 resin was then found to be capable of isolating GA from a synthetic crude mixture of GA and neutral sugars with a dynamic binding capacity of 1.31 mmol mL-1 resin. However, further work is needed to enable this anion exchange step to achieve satisfactory separations with the decolourised crude hydrolysate. The isolated neutral sugars, after GA removal, can be processed on the SMB with comparable separation performance and throughput to a mixture of neutral sugars prepared without GA. In summary, this thesis presents two possible process paths each with their own benefits and drawbacks. CPC is capable of processing the crude SBP hydrolysate directly, isolating the sugars and removing the coloured contaminants in a single step. However, Ara co-elutes with Gal providing a stream that is only 84% pure. In SMB, the potential throughputs and separation performance are higher, however, this could only be experimentally demonstrated with synthetic crude mixtures of sugars and not with the crude SBP hydrolysate. Further pretreatment or SMB method development would be required in order to process the crude hydrolysate, and the resulting multistep processes may reduce the overall viability. Overall this thesis demonstrates two feasible approaches to the preparative scale separation of SBP pectin hydrolysates and supports development of an integrated SBP biorefinery.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Smith, Mahlon A. "A study of the teaching methods of comprehension through isolation and context." CSUSB ScholarWorks, 1986. https://scholarworks.lib.csusb.edu/etd-project/325.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Xu, Yue. "Isolation and characterization of components from whey." Thesis, View thesis, 1996. http://handle.uws.edu.au:8081/1959.7/248.

Texto completo

Resumen

The structure, functionality, isolation methods and applications of whey components, particularly the proteins and lactose, have been extensively studied. These studies have had a great impact on the food industry where whey components are increasingly being used as food ingredients. Two generations of whey protein product, namely Lactalbumin, produced by heat-induced precipitation, and Whey Protein Concentration/ Isloate, produced by ultrafiltration/ ion exchange chromatography, have been commercialised. Crystalline lactose in the food and pharmaceutical grades is also being produced. Recently, research activities in whey fractionation have shifted to the isolation of the minor components. This thesis is aimed at developing a Total Whey Utilization strategy by which the several components of the whey stream would be completely recovered by fractionation, resulting in little or no residue to be disposed of in the wastewater stream. Therefore, this study was initially dedicated to the development of novel separation methods which would be suitable for the Total Whey Utilization process. The development of those techniques revealed some previously unknown feature of whey components. The mechanisms of the separation methods have been also investigated. Although crystallization is an efficient method for fractionation or purification, its disadvantage is that the mother liquor is a wastewater containing high salt and BOD (Biological Oxygen Demand). The chromatographic method has been investigated in this work to separate the mother liquor or permeate into lactose and mineral fractions such that a goal of this thesis, namely a 'clean' water stream after processing whey, can be finally achieved. These studies have focused on the effect of resin type, salt form of the resin and the operating conditions on the separation of the lactose and mineral fraction.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Fillion, Bergeron Marianne. "Plasmid isolation and purification by electrofiltration and comparison of different direct colony sequencing methods and PCR-based sequencing methods." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6050.

Texto completo

Resumen

We have designed an electrophoresis system that can purify plasmid DNA from a culture without centrifugation. This system is based on electrofiltration where bacterial cell lysates are loaded in one chamber and the purified plasmid DNA is recovered in an adjacent chamber. These two chambers are separated by a membrane made of regenerated cellulose, which allows plasmid DNA to migrate to the recovery chamber while retaining most contaminants in the loading chamber. Unfortunately, even with the optimization of the parameters involved in the electrofiltration, the only DNA that can pass through the middle membrane still has some contaminants, which prevent sequencing of the plasmid. Our results have shown that a pure plasmid cannot cross a membrane with pores small enough to prevent the migration of most of the contaminants. Only a plasmid complexed with some contaminants can cross a small pore membrane. In parallel, we have compared six direct sequencing methods that do not require any plasmid purification prior to the sequencing reaction. We compared the reliability, quality of sequences, time required, and cost of these six methods. We found that the best method was that of Zhang et al. (1999). This method is fast, reliable, produces good quality sequences and is inexpensive. The performance of this method is due to the amount of ABI's ready reaction mix used, the pre-sequencing heating step to lyse the cell, the large volume of the PCR sequencing reaction and the addition of BSA.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Svärd, Carl. "Methods for Automated Design of Fault Detection and Isolation Systems with Automotive Applications." Doctoral thesis, Linköpings universitet, Fordonssystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-77073.

Texto completo

Resumen

Fault detection and isolation (FDI) is essential for dependability of complex technical systems. One important application area is automotive systems, where precise and robust FDI is necessary in order to maintain low exhaust emissions, high vehicle up-time, high vehicle safety, and efficent repair. To achieve good performance, and at the same time minimize the need for expensive redundant hardware, model-based FDI is necessary. A model-based FDI-system typically comprises fault detection by means of residual generation and residual evaluation, and finally fault isolation. The overall objective of this thesis is to develop generic and theoretically sound methods for design of model-based FDI-systems. The developed methods are aimed at supporting an automated design methodology. To this end, the methods require a minimum of human interaction. By means of an automated design methodology the overall design process becomes more efficient and systematic, which also contributes to higher quality. These aspects are of particular importance in an industrial context. Design of a model-based FDI-system for a complex real-world system is an intricate task that poses several difficulties and challenges that must be handled by the involved design methods. For instance, modeling of these systems often result in large-scale, non-linear, differential-algebraic models. Furthermore, despite substantial modeling work, models are typically not able to capture the behaviors of systems in all operating modes. This results in model-errors of time-varying nature and magnitude. This thesis develops a set of methods able to handle these issues in a systematic manner. Two methods for model-based residual generation are developed. The two methods handle different stages of the design of residual generators. The first method considers the actual residual generator realization by means of sequential residual generation with mixed causality. The second method considers the problem of how to select an optimal set of residual generators from all possible residual generators that can be created with the first method. Together the two methods enable systematic design of a set of residual generators that fulfills a stated fault isolation requirement. Moreover, the methods are applicable to complex, large-scale, and non-linear differential-algebraic models. Furthermore, a data-driven method for statistical residual evaluation is developed. The method relies on a comparison of the probability distributions of residuals and exploits no-fault data from the system in order to learn the behavior of no-fault residuals. The method can be used to design residual evaluators capable of handling residuals subject to stochastic uncertainties and disturbances caused by for instance time-varying model errors. The developed methods, as well as the potential of an automated design methodology, are evaluated through extensive application studies. To verify their generality, the methods are applied to different automotive systems, as well as a wind turbine system. The performances of the obtained FDI-systems are good in relation to the required engineering effort. Particularly, no specific adaption or no tuning of the methods, or the design methodology, were made.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Ramesh, Ram S. "Identification of Multi-Dimensional Elastic and Dissipation Properties of Elastomeric Vibration Isolators." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515109658022859.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Sharp, Julia Lynn. "New Statistical Methods for Analyzing Proteomics Data from Affinity Isolation LC-MS/MS Experiments." Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/sharp/SharpJ0807.pdf.

Texto completo

Resumen

The field of proteomics is exploding with statistical problems waiting to be explored. To obtain information on protein complexes, interactions between protein pairs is initially examined. This exploration is performed using `bait-prey' protein pull-down assays that use a protein affinity agent and an LC-MS/MS (liquid chromatography-tandem mass-spectrometry)-based protein identifcation method. An experiment generates a protein association matrix wherein each column represents a sample from one bait protein, each row represents one prey protein and each cell contains a presence/absence association indicator. The prey protein presence/absence pattern is assessed with a Likelihood Ratio Test (LRT) and simulated LRT p-values. Fisher's Exact Test and a conditional frequency distribution test using generating functions are also used to assess the prey protein observation pattern. Based on the p-value, each prey protein is assigned a category (Specific or Non-Specific) and appraised with respect to the goal and design of the experiment. The Bayes' Odds is calculated for each prey-bait pair in the `Specific' category to estimate the posterior probability that two proteins interact and compared to an approach used by Gilchrist et al. [23]. The method is illustrated using an experiment investigating protein complexes of Shewanella oneidensis MR-1 at the Proteomics Facility of Pacific Northwest National Laboratory (PNNL). The example analysis shows the results to be biologically sensible and more realistic than methods previously used to infer protein - protein associations. While inferring protein-protein associations is of great importance in proteomic studies, the quality of the data is of equal or greater importance. Protein-protein interactions may be inferred incorrectly or not at all depending on the quality of the data. Prior to this thesis, statistical quality control measures have not been incorporated into these experiments. The implementation of traditional Individual/Moving Range (IMR) charts and cumulative sum (cusum) quality control methods for use with pull-down experiment data is studied. These methodologies are illustrated using a standard protein mixture from PNNL. The joint application of IMR and cusum charts promises to provide researchers with information on changes in the mean and variability of the data resulting from control samples run through the mass spectrometer process.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Odendaal, Hendrik Mostert. "An analysis and comparison of two methods for UAV actuator fault detection and isolation." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71780.

Texto completo

Resumen

Thesis (MScEng)--Stellenbosch University, 2012. ENGLISH ABSTRACT: Fault detection and isolation (FDI) is an important aspect of effective fault tolerant control architectures. The Electronic System Laboratory at Stellenbosch University identified the need to study viable methods of FDI. In this research two FDI methods for actuator failures on the Meraka Modular UAV are investigated. The Meraka Modular UAV is an unmanned aircraft that was developed by the CSIR. A simple six degree of freedom non-linear mathematical model is developed that presents a platform on which the two FDI methods are formulated. The theoretical model is used in a simulation environment to extensively test and compare the performance of the proposed FDI methods in different types of flight conditions. The first method investigated is a multiple model adaptive estimator (MMAE), which incorporates a bank of Kalman filters. Each Kalman filter in the MMAE is conditioned for each expected actuator fault scenario. The limitations of using linear Kalman filters are explained and they are replaced by extended Kalman filters, whose associated advantages and disadvantages are discussed. Each filter in the bank of Kalman filters produces a residual vector and residual covariance matrix. This information is subjected to a Bayes classifier to determine the fault scenario which will have the highest likelihood of being active. The second method that is studied incorporates the parity space approach for FDI. The parity space consists of the parity relations that quantify all the analytical redundancies available between the sensors’ outputs and actuator inputs of a system. A transformation matrix is then optimised to transform these parity relations into residuals that are specially sensitive to specific actuator faults. Actuator faults cause the parity space residuals’ variance to increase. A cumulative summation procedure is used to determine when the residuals’ variance has changed sufficiently to indicate an actuator fault. A pseudoinverse actuator estimation scheme is used to extract the actuator deflections from the parity relations. The FDI performance is tested by deliberately failing specific actuators of the Meraka Modular UAV in-flight. The flight test data is then used to analyse and compare the performance of the two FDI methods investigated in the research. It is found that, for the specific Meraka Modular UAV, the FDI performs as expected with disturbance effects and actuator excitation influencing the FDI effectiveness. The research shows that the bank of Kalman filters creates less false alarms whereas the parity space FDI is more sensitive to faults. It is illustrated that FDI can be improved with active actuator excitation and process noise estimation techniques, delivering promising results. AFRIKAANSE OPSOMMING: Fout-deteksie en -isolasie (FDI) is belangrik vir ’n stelsel se beheerder om foute te kan hanteer. Die Elektroniese Stelsellabaratorium (ESL) by die Universiteit van Stellenbosch het die behoefte geïdentifiseer om te gaan kyk na moontlike FDI-stelsels wat gebruik kan word op hul onbemande vliegtuie (OV). In hierdie navorsing is daar na twee FDI-metodes gekyk wat op die Meraka Modulêre OV toegepas kan word. Die Meraka Modulêre OV is ’n vliegtuig wat deur die WNNR ontwikkel is. ’n Eenvoudige sesgrade- van-vryheid, nie-liniêre wiskundige model van die Meraka Modulêre OV is ontwikkel, en die FDI-metodes is rondom hierdie model geformuleer. Die teoretiese model is gebruik in ’n simulasie-omgewing en die werkverrigting van die twee FDI-metodes is in verskillende vlug-omstandighede getoets en vergelyk. Die eerste metode waarna gekyk is, was ’n multi-model aanpasbare afskatter (MMAA), wat ’n bank van Kalman-filters gebruik. Elke Kalman-filter in die MMAA is gekondisioneer vir elke denkbare aktueerder-fout. Die beperkinge rondom liniêre Kalman-filters is uitgelig en vergelyk met uitgebreide Kalman-filters, waarvan die voor- en nadele bespreek is. Elke filter in die MMAA produseer ’n residu-vektor en residu-kovariansiematriks. Hierdie informasie is na ’n Bayes-klassifiseerder gestuur om te bepaal watter fout-senario die grootste waarskynlikheid het om aktief te wees. Die tweede metode waarna gekyk is, het die pariteitsruimte vir FDI gebruik. Die pariteitsruimte is uit al die pariteitsverwantskappe opgebou wat die verhoudings tussen al die insette en uitsette van ’n sisteem kwantifiseer. ’n Transformasie-matriks is geoptimaliseer om hierdie pariteitsverwantskappe te transformeer na residue wat elkeen sensitief is tot ’n spesikiefe aktueerderfout. ’n Spesifieke aktueerderfout veroorsaak dat ’n spesifieke residu se variansie verhoog. ’n Kummulatiewe sommeringsproses is dan gebruik om te bepaal of die variansie genoegsaam toegeneem het. Sodoende kon daar bepaal word of ’n fout ontstaan het. ’n Pseudo-inversaktueerder-afskattingstegniek is gebruik om die afgeskatte aktueerderdefleksie uit die pariteitsverwantskappe te onttrek. Die FDI-werkverrigtinge van die twee metodes is getoets deur sekere aktueerders met opset te laat faal gedurende vlugtoetse. Die vlugtoetsdata is gebruik om die werkverrigting van die FDI-metodes te analiseer en met mekaar te vergelyk. Met die spesifieke Meraka Modulêre OV is, soos te wagte, bevind dat versteurings en aktueerderopwekking ’n groot invloed op die FDI’s se werkverrigtinge toon.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Duffy, Geraldine. "The development of rapid methods for the isolation and detection of Listeria monocytogenes from meat." Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339253.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Walker, Kristen Elizabeth. "Effects of isolation methods on proliferation and GD2 expression by porcine umbilical cords stem cells." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/7067.

Texto completo

Resumen

Master of Science Department of Animal Sciences and Industry Duane L. Davis Cell isolation method may have effects on the characteristics of the cells isolated from porcine umbilical cords. As stem cells age or approach senescence, it is hypothesized that their properties change. We expect that isolation method and age of cells will have effects on the phenotype of porcine umbilical cord (PUC) cells during in vitro expansion. We investigated the effects of three isolation methods on PUC population doublings, ability to produce colony forming units (CFU), and amount of ganglioside GD2 (GD2) expression over eleven passages. Isolation methods were explant (Exp) in which the Wharton's Jelly was removed from cords, minced and plated, enzyme digest (Dig), and stomacher assisted enzyme digestion (Stom). Cell isolates were analyzed for GD2 expression, CFU, and population doublings at early (3), middle (7), and late (11) passage. The Exp method produced greater (P<0.05) population doublings and more (P<0.05) CFU at passage 7. Explant isolates also were numerically more likely to survive to passage 11 (9/9 isolates vs 5/9 for Dig and 7/9 for Stom). In contrast, the percent cells expressing GD2 was greater (P<0.05) for Stom isolates than Exp isolates at passage 11. There were no trends for increased passage number to decreased population doubling, CFU formation, or percent GD2 positive cells. In summary, our results indicate that the Exp isolation method produced the greatest number of population doublings over 11 passages and there were minimal effects of isolation method on CFU and GD2 expression. Although Exp may be more difficult to scale up to isolate all of the PUCs in a cord, it provided greater in vitro expansion than the enzyme methods in our experiment and may provide the most cells for biotechnological and biomedical applications.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Kayed, Dima 1960. "METHODS FOR THE ISOLATION OF OOCYSTS OF CRYPTOSPORIDIUM FROM SLUDGE AND GIARDIA CYSTS FROM STOOL." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276355.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Krysander, Mattias. "Design and Analysis of Diagnosis Systems Using Structural Methods." Doctoral thesis, Linköping : Linköpings universitet, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7417.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Little, Gareth Thomas. "The isolation, characterisation and development of genetic methods for a new solventogenic strain of Clostridium beijerinckii." Thesis, University of Nottingham, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.718984.

Texto completo

Resumen

In recent times research has returned to focus on the development of sustainable alternatives to fossil fuel based transport fuels. The drivers for this research are the twin issues of improving supply security and concerns over global warming caused by increased greenhouse gas emissions. For a competing fuel to be economically viable it must be cheap to produce, be compatible with existing fuel infrastructure, and not impact upon conventional agriculture. Butanol produced from the fermentation of waste lignocellulose as a feedstock fits the bill for the requirements of a sustainable fuel production process. Butanol can be used in existing combustion engines with limited modification, while using waste lignocellulose as a feedstock represents a cheap, plentiful, sustainable source of energy. Historically butanol, alongside acetone and ethanol, was produced in an industrial fermentation by the bacterium Clostridium ocetobutylicum during the early 20th Century. The goal of the research presented in this thesis is to isolate a solvent producing strain of Clostridium that can be manipulated for use in an industrial process for the production of butanol. A candidate strain of Clostridium beijerinckii was isolated from garden soil that showed promising levels of solvent production and was able to grow on both hexose and pentose sugars. The genome sequence of the organism was obtained using a combination of two different next-generation sequencing technologies. Tools for the genetic manipulation of the strain including ClosTron disruption, Allele Coupled Exchange, in-frame deletion and random mutagenesis were exemplified. In addition an efficient electrotransformation procedure was developed for this organism that could have wider implications for research on Clostridium spp.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Víquez, Ana M. "Isolation and characterization of alkane monooxygenase (alkB) genotypes from Arctic contaminated soils by culture-independent methods." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98510.

Texto completo

Resumen

Alkane monooxygenases (encoded by the alkB gene) are a group of microbial enzymes that catalyze the first reaction of alkane degradation. Studies to determine the diversity and prevalence of alkB genotypes in the environment have focused on culturable organisms. The goal of this research was to use culture-independent methods (DGGE, clone library) to identify and characterize alkB genes, and to determine their prevalence in Arctic contaminated soils. General alkB PCR degenerate primers (alkB-Mc) were designed using the conserved nucleotide sequences of the Histidine I Box and Histidine III Box. General alkB-Mc and alkM (Acinetobacter spp. alkane monooxygenase genes) primers were used to screen the soils for the presence of alkane monooxygenase genotypes. A predominance of the Rhodococcus spp. alkB genotypes and the absence of alkM genotypes in these soils was found. alkB PCR fragments amplified from the soils were analyzed by DGGE (Denaturing Gradient Gel Electrophoresis). BlastN and blastX results of the DGGE bands sequences showed that they were similar to Rhodococcus spp. alkB genotypes (~80-90% DNA identity and ~80-90% amino acid homology). An alkB clone library was built using the general alkB-Mc primer set, screened by RFLP (Restriction Fragment Length Polymorphism) and characterized by sequencing of alkB clones. BlastN and blastX results of the alkB clone sequences showed the presence of divergent alkB genotypes (≤ 70% DNA identity and ≤ 67% of amino acid homology to data base sequences). The alignment of the clone-derived amino acid sequences to confirm functional alkane monooxygenase sequences revealed the presence of Histidine Box II and the HYG motif in all of the deduced amino acid clone sequences. These results indicate that the alkB sequences from the clone library represent novel alkB sequences. Both alkB DGGE and clone library techniques were independently able to identify alkB genotypes from High G+C microorganisms as predominant in the 1A03 soil sample. Nevertheless, only the clone library approach identified putative novel alkB sequences. Mineralization of hexadecane and naphthalene was clearly observed at subzero temperatures (-5ºC) in Arctic contaminated soils, proving that the indigenous microbial communities could mineralize these representative hydrocarbons at subzero temperatures in an environment that is predominantly frozen for most of the year.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Watanabe, S., K. Gagnon, D. K. Hamlin, M. K. Chyan, E. Balkin, and D. S. Wilbur. "Evaluation of Column Separation Methods for Simplification of the Wet Chemistry Approach to Isolation of 211At." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-164241.

Texto completo

Resumen

Difficulties with reproducibility of isolation yields when distilling 211At from irradiated bismuth targets led us to use a “wet chemistry” approach for that process1. The wet chemistry approach has provided 211At isolation yields of ~ 78 % after decay and Bi attenuation corrections2. However, the use of diisopropyl ether (DIPE) in the separation process has made it difficult to reach our goal of automating the 211At isolation. Therefore, we have investigated the use of column materials to simplify the isolation of 211At and remove DIPE from the process. In this investigation we evaluated the use of a strong anion exchange resin (AG1×8), a strong cation exchange resin (AG MP-50) and a polyethylene glycol (PEG)-coated resin for separation of 211At from the bismuth target material. Anion and cation resins AG1×8 and AG MP-50 were obtained from commercial sources. A PEG-coated resin was prepared by reaction of the Merrifield resin with mPEG-OH 2000 in the pres-ence of tBuOK at 80 °C for 3 days, followed by drying under vacuum. Prior to use of the PEG resin, it was soaked in H2O. Resins (400–800 mg) were loaded into polypropylene columns (Applied Separations, Inc.). Column elution studies were conducted with and without reductants (0.75M FeSO4/1M H2SO4 or Na2S2O5) to determine their effect on capture of 211At. After target dissolution in HNO3 (and in most cases subse-quent removal of HNO3 by distillation and redis-solution of solid in 8M HCl), 211At solution was loaded onto the column, then the column was washed with 2M HCl or H2O to separate the Bi, and finally was eluted with strong base to remove the 211At. Initial studies were conducted with stable iodine to determine if reductants were effective in the presence of large amounts of bismuth ions. Studies with AG1×8 used 125I to determine if that radiohalogen could be captured and recovered from the column when eluting with boric acid buffers at pH 5.3, 8.0 or 10, or H2O at pH 7. Capture and recovery of 211At was evaluated under the same conditions. Further studies with AG1×8 involved eluting with 4M H2SO4. A limited study with AG MP-50 resin used 1M HCl as eluant. Studies with PEG-coated columns used 2M HCl, 4M HCl, 8M HCl, 16 M HNO3 and 8M HNO3 as initial (capture) eluants. Strong base (0.2, 1 or 12.5 M NaOH; 15M NH4OH) and 3 or 500 mM tetrabutylammonium bromide (TBAB) were evaluated for removal of 211At from the columns tested. The efficiency for capture of 211At on the AG1×8 column was high (99%) when loading with strong acid, but decreased when using 0.1–0.2M boric acid (69–91 %) buffer. Low 211At capture efficiencies were obtained with AG MP-50 col-umns (15–29%). High 211At capture efficiencies (96–100%) were obtained with PEG-coated resins when loading with 8M HCl or 8M HNO3, irre-spective of whether reductant was in the acid solution. Four column washings (2 mL of 2M HCl each) were required to remove all Bi prior to elution of 211At. No bismuth was detected in solution from the 4th washing in any of the elutions studied. Low (< 6%) recovery of 211At from the AG1×8 columns was obtained using the conditions studied. Good (60–79%) recovery of 211At was obtained from PEG-coated resin using 15M NH4OH. Isolation of the 211At from NH4OH solution was accomplished by distillation. In an initial study 211At distilled before obtaining a dry residue. However, later studies demonstrated that addi-tion of NaOH prior to distillation kept the 211At in the distilling flask. These studies demonstrated that PEG-coated columns could be used to isolate 211At from HNO3-dissolved bismuth targets with good non-optimized (~60%) overall recovery yields. The studies are continuing with optimization of elu-tion conditions and automation of the process.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Duru, Betul. "Isolation Of A Bioactive Compound Hypericin From A Medicinal Plant Hyppericum Perforatum L. Using Basic Chromatography Methods." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/12604846/index.pdf.

Texto completo

Resumen

Medicinal plants which have been widely used in folk medicine are known to contain important biologically active compounds. Most of today&rsquo s synthetic drug raw materials are to be prepared by using plant originated compounds as the starting material. Hypericum Perforatum is one of the medicinal plants that grows in Europe, Western Asia and Northern Africa and is distinguished by its golden yellow flowers. The common name of the plant is St. John&rsquo s wort. From the time of the ancient Greeks down through the middle Ages, the plant was considered to be imbued with magical powers and was used to ward off evil and protect against disease. As a practical folk-remedy, it has been used widely to heal wounds, remedy kidney troubles, and alleviate nervous disorders, even insanity. In the last thirty years, Hypericum perforatum has undergone extensive clinical and laboratory testing. The extract of the flower is a red liquid that contains many biologically active compounds such as: naphtodianthrones (hypericin, pseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, hyperoside, quercitrin, isoquercitrin, rutin, campferol, myricetin, amentofloavone), procyanidins (procyanidin, catechin, epicatechin polymers) , tannins (tannic acid), essential oils (terpenes, alcohols), amino acids (GABA, Cysteine, glutamine, leucine, lysine, ornithine, praline, threonine), phenyl propanes (caffeic acid, chlorogenic acid), xanthones (keilcorin, norathriol), organic acids peptides and polysaccharides (other water soluble compounds). These compounds have previously been isolated using HPLC method. The aim of this study is to isolate the main biologically active compound groups of Hypericum Perforatum and simply characterize the compounds with TLC, UV-VIS spectroscopy, NMR spectroscopy using standard compounds as references.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Nordén, Johan. "Assessment of methods for microRNA isolation, microRNA amplification, and development of a normalization strategy for sepsis biomarker research." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-18442.

Texto completo

Resumen

Sepsis, defined by organ dysfunction caused by an adverse immune response of the host to an infection, comes with considerable cost in human lives and as a substantial burden financially. Significant upgrades have been made over the past two decades when diagnosing and treating sepsis but still with room for improvements. Early detection is a cornerstone in the fight against sepsis, and the focus on strengthening diagnostics is in the forefront of modern research. The implementation of biomarkers may be the path of progression in this objective. This study aimed at establishing procedural foundations when using microRNAs as potential biomarkers. The study conducted looked at: (1) Isolation procedure, of microRNA from human plasma, of three kits: Total RNA Purification Kit (Norgen Biotech), miRNAeasy Serum/Plasma Kit (Qiagen), and miRNeasy Serum/Plasma Advanced Kit (Qiagen). (2) Amplification of miRNA through two Reverse Transcription Quantitative PCR methods: Two-tailed RT-qPCR (TATAA Biocenter), and miRCURY LNA miRNA PCR (Qiagen). (3) Developing a normalization strategy by identifying miRNA reference targets in a geNorm pilot experiment. Qubit analysis revealed that the two isolation kits from Qiagen performed similar, and better that the Norgen kit. The Two-tailed RT-qPCR failed to amplify miRNA samples, whereas the miRCURY LNA miRNA PCR showed consistent amplification across samples with a high call rate. The geNorm analysis concluded that hsa-miR-425-5p and hsa-miR-93-5p was the optimal reference target set. The study demonstrated that the isolation kits from Qiagen coupled with the miRCURY LNA miRNA PCR is a viable option for future miRNA biomarker studies.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Smith, Joseph Robert. "Methods for isolating, expanding, and characterizing umbilical cord mesenchymal stromal cells and their in vitro metabolism." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35462.

Texto completo

Resumen

Master of Science in Biomedical Sciences Department of Anatomy and Physiology Mark L. Weiss Mesenchymal stromal cells (MSCs) derived from the umbilical cord (UC-MSCs) have therapeutic applications and are studied to understand their potential uses and immunomodulatory properties. Research must identify good manufacturing process (GMP) compliant methods to isolate and expand UC-MSCs. In addition, MSCs metabolism characteristics in culture are unknown, warranting further investigation. Viability of MSCs decreases after cryopreservation, which is detrimental to clinical translation. Previously published methods used to isolate MSCs from the umbilical cord included open dissection steps and xenogeneic components. Here, I developed improved methods by eliminating dissection which reduces contamination risks. Instead, I used the whole umbilical cord and Miltenyi dissociator tubes to mechanically and enzymatically dissociate cells in a closed system. Xenogeneic components were decreased by using medium containing pooled human platelet lysate instead of fetal bovine serum. The cell numbers isolated from umbilical cord averaged 2.68 x 10⁵ per cm, which represents greater than 20 fold improvement over the previous method. Moreover, expansion cell numbers were increased using 10% pooled human platelet lysate supplemented media. The UC-MSCs generated here met the International Society of Cell Therapy (ISCT) definition of MSCs. Metabolism characteristics of MSCs indicated that glucose was the critical metabolite, maintaining cells longer in culture than glutamine. Cell death followed depletion of glucose, too. Finally, the average viability after thawing cryopreserved MSCs was more than 95%, higher than previous methods. The improvements I introduced to our methodology could speed clinical translation of MSCs as an allogeneic cellular therapy

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Rip, Diane. "Sample preparation methods and molecular based detection for the rapid isolation and identification of Listeria monocytogenes in food samples." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1346_1255007553.

Texto completo

Resumen

Listeria monocytogenes is a Gram-positive bacterium responsible for listeriosis, a food-borne disease, which may result in severe illness and possible death. The importance of L. monocytogenes as a food-borne pathogen has been recognized since the 1980's when a correlation between the cunsumption of contaminated foodstuffs and human listeriosis outbreaks was observed. Listeriosis occurs with the ingestion of contaminated foods. The aim of this study involved developing DNA based methods to aid the food industry for the fast detection of L. monocytogenes in food products. Therefore assays were developed in such a way that they will have potential applications in the food idustry.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Pohanka, Anton. "Antifungal antibiotics from potential biocontrol microorganisms /." Uppsala : Department of Chemistry, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200647.pdf.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Xu, Feng. "Diagnosis and fault-tolerant control using set-based methods." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/284831.

Texto completo

Resumen

The fault-tolerant capability is an important performance specification for most of technical systems. The examples showing its importance are some catastrophes in civil aviation. According to some official investigations, some air incidents are technically avoidable if the pilots can take right measures. But, relying on the skill and experience of the pilots, it cannot be guaranteed that reliable flight decisions are always made. Instead, if fault-tolerant strategies can be included in the decision-making procedure, it will be very useful for safer flight. Fault-tolerant control is generally classified into passive and active fault-tolerant control. Passive fault-tolerant control relies on robustness of controller, which can only provide limited fault-tolerant ability, while active fault-tolerant control turns to a fault detection and isolation module to obtain fault information and then actively take actions to tolerate the effect of faults. Thus, active fault-tolerant control generally has stronger fault-tolerant ability. In this dissertation, one focuses on active fault-tolerant control, which for this case considers model predictive control and set-based fault detection and isolation. Model predictive control is a successful advanced control strategy in process industry and has been widely used for processes such as chemistry and water treatment, because of its ability to deal with multivariable constrained systems. However, the performance of model redictive control has deep dependence on system-model accuracy. Realistically, it is impossible to avoid the effect of modelling errors, disturbances, noises and faults, which always result in model mismatch. Comparatively, model mismatch induced by faults is possible to be effectively handled by suitable fault-tolerant strategies. The objective of this dissertation is to endow model predictive control with fault-tolerant ability to improve its effectiveness. In order to reach this objective, set-based fault detection and isolation methods are used in the proposed fault-tolerant schemes. The important advantage of set-based fault detection and isolation is that it can make robust fault detection and isolation decisions, which is key for taking right fault-tolerant measures. This dissertation includes four parts. The first part introduces this research, presents the state of the art and gives an introduction of used research tools. The second part proposes set-based fault detection and isolation for actuator or=and sensor faults, which are involved in interval observers, invariant sets and set-membership estimation. First, the relationship between interval observers and invariant sets is investigated. Then, actuator and sensor faults are separately coped with depending on their own features. The third part focuses on actuator or=and sensor fault-tolerant model predictive control, where the control strategy is robust model predictive control (tube-based and min-max approaches). The last part draws some conclusions, summarizes this research and gives clues for the further work. La capacidad de los sistemas para tolerar fallos es una importante especificación de desempeño para la mayoría de sistemas. Ejemplos que muestran su importancia son algunas catástrofes en aviación civil. De acuerdo a investigaciones oficiales, algunos incidentes aéreos son técnicamente evitables si los pilotos pudiesen tomar las medidas adecuadas. Aun así, basándose en las habilidades y experiencia de los pilotos, no se puede garantizar que decisiones de vuelo confiables serán siempre posible de tomar. En cambio, si estrategias de tolerancia a fallos se pudieran incluir en el proceso de toma de decisión, los vuelos serían mucho más seguros. El control tolerante a fallos es generalmente clasificado en control pasivo y activo. El control pasivo se basa en la robustez del controlador, el cual sólo provee una habilidad limitada de tolerancia a fallos, mientras que el control tolerante a fallos de tipo activo se convierte en un modulo de detección y aislamiento de fallos que permite obtener información de éstos, y luego, activamente, tomar acciones para tolerar el efecto de dichos fallos. Así pues, el control activo generalmente tiene habilidades más fuertes de tolerancia a fallos. Esta tesis se enfoca en control tolerante a fallos activo, para lo cual considera el control predictivo basado en modelos y la detección y aislamiento de fallos basados en conjuntos. El control predictivo basado en modelos es una estrategia de control exitosa en la industria de procesos y ha sido ampliamente utilizada para procesos químicos y tratamiento de aguas, debido a su habilidad de tratar con sistemas multivariables con restricciones. A pesar de esto, el desempeño del control predictivo basado en modelos tiene una profunda dependencia de la precisión del modelo del sistema. Siendo realistas, es imposible evitar el efecto de errores de modelado, perturbaciones, ruidos y fallos, que siempre llevan a diferencias entre el modelo y el sistema real. Comparativamente, el error de modelo inducido por los fallos es posible de ser manejado efectivamente por estrategias adecuadas de control tolerante a fallos. Con el fin de alcanzar este objetivo, métodos de detección y aislamiento de fallos basados en conjuntos son utilizados en los esquemas de tolerancia a fallos propuestos en esta tesis. La ventaja importante de estas técnicas de detección y aislamiento de fallos basadas en conjuntos es que puede tomar decisiones robustas de detección y aislamiento, lo cual es clave para tomar medidas acertadas de tolerancia a fallos. Esta tesis esta dividida en cuatro partes. La primera parte es introductoria, presenta el estado del arte y hace una introducción a las herramientas de investigación utilizadas. La segunda parte expone la detección y aislamiento de fallos en actuadores y/o sensores, basándose en teoría de conjuntos, a partir de observadores de intervalo, y conjuntos invariantes. La tercera parte se enfoca en el control predictivo robusto (con enfoques basados tanto en tubos robustos como en min-max) con tolerancia a fallos en actuadores y/o sensores. La cuarta parte presenta algunas conclusiones, hace un resumen de esta investigación y da algunas ideas para trabajos futuros.

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Kim, Moon Koo. "Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methods." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1099.

Texto completo

Resumen

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, toxic contaminants that are released to the environment from various petrogenic and pyrogenic sources. In an effort to more clearly identify and trace sources of PAHs in the environment, purification and compound specific isotope analysis methods were developed to accurately measure the stable carbon isotope ratio of individual PAHs. Development of the method included improving accuracy and precision of the isotopic measurement by producing highly pure extracts using various chromatographic techniques. The method was refined by improving compound separations using purification techniques and high resolution chromatographic columns. The purification method consists of alumina/silica gel column chromatography, gel permeation chromatography and thin layer chromatography. The mean recovery of PAHs after the purification procedure was approximately 80 %. Sample purities after purification were verified by GC/FID and full scan mass spectrometry. To better resolve peaks and provide more accurate stable carbon isotope measurements, various gas chromatographic conditions were evaluated. The precision of the method ranged between 0.08 and 0.43 . The analytical protocols were evaluated to confirm compositional and stable isotopic integrity during purification and stable isotopic analysis. To confirm the utility of the purification and isotope analysis methods, various environmental samples from marine, land and lacustrine environments were analyzed. The isolates were analyzed for the composition and the stable carbon isotope ratios of PAHs. The stable carbon isotope ratio was measured by GC/IRMS and the results, along with quantitative compound compositions, were used to characterize and identify the contaminant sources. The sources of the PAHs in the study areas were differentiated by PAH molecular ratios and confirmed by stable carbon isotope ratios. This study confirms that compound specific isotope analysis of pollutants by GC/IRMS can be used to identify PAH sources in environmental samples. The study also confirms that the purification and stable carbon isotope analysis methods that were developed can be used to accurately measure the stable carbon isotope ratios of PAHs in environmental samples for the purpose of source identification. GC/IRMS measurement of stable isotopic compositions can be an effective fingerprinting method when used in conjunction with traditional molecular composition methods.

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Al-Busaidi, Harith N. K. "Secondary metabolites from Xylaria endophytes : the isolation and structure elucidation of secondary metabolites from Xylaria endophytes by chemical and spectroscopic methods." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5266.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Alhaidari, Rwaida Adel. "Secondary metabolites from Xylariaceous fungi : the isolation and structure elucidation of secondary metabolites from Xylariaceous fungi by chemical and spectroscopic methods." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5705.

Texto completo

Resumen

This thesis describes the isolation and structure elucidation of secondary metabolites formed in static culture from a number of endophytic Xylariaceous fungi. Four Xylaria endophytes isolated from a palm tree in Thailand were surface cultured on an aqueous malt extract-glucose medium. They all produced cytochalasin D, coriloxin, (S)-mellein and (3R,4R)-4-hydroxymellein as the main secondary metabolites suggesting that the four endophytes could be the same species. The endophytic fungus A116 produced cytochalasin D as the main secondary metabolite. Another non-endophytic fungus B315, produced cytochalasin D, (R)-mellein, a mixture of two isomers of 4-hydroxymellein and phloroglucinol. X.62, an endophytic fungus, produced 19,20-epoxycytochalasin C from the mycelium as the main secondary metabolite. The fungus Engleromyces sinensis produced engleromycin acetate as the main secondary metabolite. Fungus X. polymorpha produced (3E)-4-(3'-acetyl-2',6'-dihydroxy-5'-methylphenyl)-2-methoxybut-3-enoic acid.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Riveli, Nowo. "Direct Photon - Hadron Correlations Measurement in Au+Au Collision at NucleonCenter-Of-Mass Energy of 200 GeV With Isolation Cut Methods." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1407292084.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Alhaidari, Rwaida A. A. "Secondary metabolites from Xylariaceous fungi. The isolation and structure elucidation of secondary metabolites from Xylariaceous fungi by chemical and spectroscopic methods." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5705.

Texto completo

Resumen

This thesis describes the isolation and structure elucidation of secondary metabolites formed in static culture from a number of endophytic Xylariaceous fungi. Four Xylaria endophytes isolated from a palm tree in Thailand were surface cultured on an aqueous malt extract-glucose medium. They all produced cytochalasin D, coriloxin, (S)-mellein and (3R,4R)-4-hydroxymellein as the main secondary metabolites suggesting that the four endophytes could be the same species. The endophytic fungus A116 produced cytochalasin D as the main secondary metabolite. Another non-endophytic fungus B315, produced cytochalasin D, (R)-mellein, a mixture of two isomers of 4-hydroxymellein and phloroglucinol. X.62, an endophytic fungus, produced 19,20-epoxycytochalasin C from the mycelium as the main secondary metabolite. The fungus Engleromyces sinensis produced engleromycin acetate as the main secondary metabolite. Fungus X. polymorpha produced (3E)-4-(3¿-acetyl-2¿,6¿-dihydroxy-5¿-methylphenyl)-2-methoxybut-3-enoic acid. Ministry of Higher Education; Kingdom of Saudi Arabia.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Al-Busaidi, Harith. "Secondary Metabolites from Xylaria Endophytes: The isolation and structure elucidation of secondary metabolites from Xylaria endophytes by chemical and spectroscopic methods." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/17479.

Texto completo

Resumen

This thesis describes the isolation and structure elucidation of secondary metabolites from a number of endophytic Xylaria fungi. Six Xylaria endophytes were surface cultured on an aqueous malt extract-glucose medium. The fungus A311R, from a palm tree in Thailand, produced nonane-1,2,3-tricarboxylic acid, which was isolated for the first time as a natural product. Also isolated from the same fungus was spiculisporic acid; the first instance of isolation from a Xylaria fungus. The fungus 6RD12 produced cycloepoxydon, which was isolated for the first time from a Xylaria fungus, and 4,5,6-trihydroxy-3-propyl-3,4,6,7-tetrahydro-l//-isochromen- 8(5//)-one, which is a novel compound. The fungi A217R and A517R produced cytochalasin D, (S)-mellein and (3S,4S)-4-hydroxymellein as main secondary metabolites suggesting that the two fungi are the same species. The fungus X04 (Xylaria cf. juruensis) produced 2-Hydroxy-5-ethoxy-3-methylcyclohexa-2,5-dien- 1,4-dione as a novel compound, coriloxin as the main secondary metabolite in addition to (R)-mellein and a mixture of two stereoisomers of the 4-Hydroxymellein. The fungus 6RD8 produced (S)-Omethylmellein as the main secondary metabolite. l

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Rahman, Brian M. "Sensor Placement for Diagnosis of Large-Scale, Complex Systems: Advancement of Structural Methods." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562859497638274.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Stoican, Florin. "Fault tolerant control based on set-theoretic methods." Phd thesis, Supélec, 2011. http://tel.archives-ouvertes.fr/tel-00633622.

Texto completo

Resumen

The scope of the thesis is the analysis and design of fault tolerant control (FTC) schemes through the use of set-theoretic methods. In the framework of multisensor schemes, the faults appearance and the modalities to accurately detect them are investigated as well as the design of control laws which assure the closed-loop stability. By using invariant/contractive sets to describe the residual signals, a fault detection and isolation (FDI) mechanism with reduced computational demands is implemented based on set-separation. A dual mechanism, implemented by a recovery block, which certificates previously fault-affected sensors is also studied. From a broader theoretical perspective, we point to the conditions which allow the inclusion of {FDI} objectives in the control law design. This leads to static feedback gains synthesis by means of numerically attractive optimization problems. Depending on the parameters selected for tuning, is shown that the FTC design can be completed by a reference governor or a predictive control scheme which adapts the state trajectory and the feedback control action in order to assure {FDI}. When necessary, the specific issues originated by the use of set-theoretic methods are detailed and various improvements are proposed towards: invariant set construction, mixed integer programming (MIP), stability for switched systems (dwell-time notions).

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Glöckle, Anna [Verfasser], Tobias A. M. [Akademischer Betreuer] Gulder, Tobias A. M. [Gutachter] Gulder, and Kathrin [Gutachter] Lang. "Methods for the isolation and modification of novel polycyclic tetramate macrolactams (PoTeMs) / Anna Glöckle ; Gutachter: Tobias A. M. Gulder, Kathrin Lang ; Betreuer: Tobias A. M. Gulder." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1224313364/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Willis, Regina Marice. "Factors that Affect Job Satisfaction and Work Outcomes of Virtual Workers." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/3014.

Texto completo

Resumen

Employing a virtual workforce has become a common practice among technically advanced and globally competitive organizations. Yet there is limited information regarding factors that affect job satisfaction and work outcomes of virtual workers. The purpose of this phenomenological study was to address the problem by exploring the lived experiences of virtual workers. Principles of Bandura's self-efficacy theory and Maslow's needs theory formed the conceptual framework. Babbie's sampling strategy and social media were used to obtain 26 participants among the target population of virtual workers. By distributing an online questionnaire, data were collected and analyzed through open coding techniques. As the data were analyzed, common themes emerged. The themes affecting job satisfaction of virtual workers included work and life balance, isolation and belonging, flexibility, resource efficiency, and trust and respect. The themes affecting work outcomes of virtual workers included training and technical support, communication, and workplace distractions. Findings indicated that job satisfaction and work outcomes might vary according to the self-efficacy level, needs, and virtual competencies of the individual virtual worker. Findings may contribute to positive social change by educating individuals on the benefits and challenges of the virtual workplace. Managers may reference the study outcomes when seeking to improve hiring processes, enhance training and technological support, and assess relevant virtual competencies. Employees may consider the study outcomes when determining whether virtual work arrangements align with their professional and personal goals.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Jurečková, Nela. "PCR identifikace nepatogenních bakterií izolovaných ze sýrů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216587.

Texto completo

Resumen

Different species of genus Bifidobacterium are part of human and animal intestinal flora. These bacteria have benefit effects and therefore they are used in foods and pharmaceutical products as probiotics. Cheese is now suitable as a probiotic matrix except yoghurts and fermentated milks. This diploma thesis was focused on optimalization of DNA isolation from bacteria of genus Bifidobacterium. Magnetic microparticles (P(HEMA-co¬-GMA)) were used for DNA isolation in presence of 8% polyethyleneglycol PEG 6000 and 5 M sodium chloride. Phenol extraction weas also used as an isolation method. Isolated DNA was used for amplification in domain, genus and species specific PCRs. Optimized method was tested for detection of bacteria of genus Bifidobacterium in experimentaly prepared probiotic cheeses. These cheeses contained potential probiotic bacteria from Laktoflóra collection. Bacteria were identified into species using species specific PCR. Species Bifidobacterium animalis was identified in all samples of probiotic cheeses.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Martins, Tânia Cristina Soares. "Exosomes as tools for biomarker discovery." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21996.

Texto completo

Resumen

Mestrado em Biomedicina Molecular Os exossomas são pequenas vesículas extracelulares envolvidas em vários processos fisiológicos e patológicos. O potencial dos exosomas como fontes de biomarcadores para o diagnóstico, prognóstico e mesmo para a terapêutica tem intensificado a investigação nesta área, apoiando o potencial dos exosomas na descoberta de biomarcadores. A centrifugação diferencial é o método mais usado, mas é demorado, requer grandes volumes de amostra e as altas velocidades de centrifugação podem comprometer a integridade dos exossomas. Apesar das várias opções disponíveis, nenhum consenso foi atingido quanto à melhor metodologia para isolar exossomas. Neste estudo, dois métodos baseados em precipitação e um método baseado em colunas foram comparados para a isolação de exosomas a partir de soro, plasma e líquido cefalorraquidiano humano (LCR). Foi realizada uma completa caracterização dos exosomas isolados, incluindo a análise do tamanho e estabilidade das partículas, análise da morfologia por microscopia eletrónica de transmissão, incluindo métodos de quantificação de partículas e proteína. Todos os métodos isolaram exosomas a partir dos três biofluidos, contudo apresentaram performances diferentes em termos de rendimento exossomal. Estes dados apoiam a hipótese de que para além da ultracentrifugação outros métodos podem ser aplicados para isolar exosomas no contexto da investigação clínica e translacional. Neste estudo foi também explorado o potencial dos exosomas derivados do soro humano como transportadores de biomarcadores candidatos para a Doença de Alzheimer (DA). Estes podem representar métodos menos invasivos do que o atual diagnóstico neuroquímico para a DA, baseado no LCR. Neste caso, foi monitorizado o potencial de sAPPα e sAPPβ nos exosomas extraídos de soro de indivíduos com demência moderada, severa e casos de DA diagnosticados. Foi observada uma diminuição nas médias de sAPPα e sAPPβ dos exosomas neuronais derivados do soro, suportando o potencial dos exosomas na descoberta de biomarcadores para a DA. Exosomes are small extracellular vesicles involved in various physiological and pathological processes. The potential of exosomes as biomarker resources for diagnostics, prognostics and even for therapeutics has intensified research in the field supporting the potential of exosomes in AD biomarker discovery. Differential centrifugation is the most used method but is time-consuming, requires larger volumes of sample, and the high centrifuge speed compromise exosome integrity. Despite the various approaches available, no consensus on which is the best methodology to isolate exosomes have been reached thus far. Thus, in this study, two precipitation-based methods and one column-based method were compared for exosome isolation from human serum, plasma and cerebrospinal fluid. A complete exosome characterization was carried out, including size and particle stability analysis, morphological assessment by transmission electron microscopy and yield quantification methods. All methods isolated exosomes from the three biofluids although in terms of exosome yield they performed differently. These data support the notion that other methods than ultracentrifugation can be successfully applied to isolate exosomes, that can be further used in the context of translational and clinical research. It was also explored the value of serum-derived exosomes as carriers of candidate Alzheimer’s disease (AD) biomarkers. These may represent less invasive approaches than CSF-based neurodegenerative diagnostic currently used for AD. In this case, the potential of serum-derived exosome sAPPα and sAPPβ was monitored, in cognitive demented individuals including AD diagnosed cases. A decrease in sAPPα and sAPPβ levels of serum-derived neuronal exosomes was obtained in individuals with moderate, severe dementia and AD confirmed from respective controls, supporting the potential of exosome in AD biomarker discovery.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Tarzi, Sarah Lilly Farah. "Methicillin resistant Staphylococcus aureus (MRSA) : psychological impact of hospitalisation and MRSA isolation in an older adult population and a critique of research methods used to study pyschological issues in this population." Thesis, Open University, 1999. http://oro.open.ac.uk/58002/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

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.

Texto completo

Resumen

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)

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Tarzi, Sarah. "Methicillin resistant staphylococcus aureus (MRSA) : psychological impact of hospitalisation and MRSA isolation in an older adult population, and a critique of research methods used to study psychological issues in this population." n.p, 1999. http://ethos.bl.uk/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Gottberg, Kristina. "Studies of people living with multiple sclerosis in Stockholm county : evaluation of methods for data collection and aspects of functining and use of health care services /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-784-7/.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Martinez, Vanessa. "The Optimization of Pressure Cycling Technology (PCT) for Differential Extraction of Sexual Assault Casework." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2999.

Texto completo

Resumen

A two-step protocol has been devised as a rapid and selective alternative to conventional differential extraction techniques with an increased recovery of DNA. The protocol involves pressure cycling with the Barocycler® NEP 2320 from Pressure Biosciences. Inc. in alkaline conditions for epithelial cell lysis and removal. This step is followed by alkaline lysis at 95º C for extraction of sperm cell DNA. At 1:1 or 2:1 female to male cell ratios, high selectivity and complete separation can be achieved. But at higher ratios, male allelic dropout is observed. This protocol has been modified to generate a clean male profile at a 20:1 cell ratio through optimization of NaOH concentration and inclusion of an additional pressure cycling step. Validation studies have been performed to assess the efficiency of this method under various conditions. An additional immunomagnetic cell capture pretreatment allowed for nearly complete separation at cell ratios of up to 200:1.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Szczepanski, Mateusz. "Development of methods allowing the test and the comparison of low-voltage motors insulation systems running under partial discharges (fed by inverter)." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30073.

Texto completo

Resumen

Depuis le développement des composants d'électronique de puissance qui ont permis la fabrication d'onduleurs fiables et efficaces, les entraînements à vitesse variable utilisant des moteurs asynchrones sont devenus de plus en plus populaires. La technique MLI s'est avérée être une méthode très efficace de contrôle de la vitesse de rotation. Cependant, les impulsions de tension, avec des pentes très raides (de l'ordre de quelques kV/µs), ont apporté de nouveaux risques pour le système d'isolation électrique des moteurs. La richesse harmonique de la tension MLI entraînera une surtension significative due à une différence d'impédance entre le câble et le moteur. En effet, la tension observée par certaines parties du système d'isolation peut dépasser la tension d'apparition des décharges partielles (ang. PDIV); ce qui amorcera une activité de décharges partielles localisée. Le système d'isolation des machines basse tension (appelé type I) est basé presque entièrement sur des matériaux polymères qui ne sont pas conçus pour supporter des décharges partielles tout au long de leur vie. En raison de l'utilisation de variateurs de fréquence, l'isolation primaire du fil émaillée est en danger par rapport aux machines alimentées par réseau. En conséquence, c'est souvent le point le plus faible du système d'isolation qui conduira à la panne prématurée d'une machine. Le but de cette thèse est d'étudier et d'analyser le processus de vieillissement du fil émaillé exposé aux différents facteurs et de proposer une méthode permettant de prédire les durées de vie dans des conditions fixées. Cette étude introduit une prédiction basée sur la méthode des plans d'expériences et la distribution statistique de Weibull. Grâce au modèle obtenu avec des tests de vieillissement courts multicontraintes (température, tension, fréquence) il est possible de prédire les résultats de tests significativement plus longs. De plus, la méthodologie proposée permet de prédire la dispersion des essais longs en se basant sur la dispersion des résultats à court terme. Les prédictions sont comparées avec les données expérimentales afin de prouver la précision du modèle Since the development of power electronic components, which allowed the manufacturing of reliable and efficient inverters, variable speed drives using inductive motors have become more and more popular. The PWM technique has proven to be a very effective method of rotational speed control. However, the fast changing voltage pulses, with very steep slopes (in the order of a few kV/µs), has brought new hazards for the electrical insulation system of such motors. Very high frequency harmonic components of PWM voltage will result in significant overvoltage due to an impedance mismatch between the cable and the motor. As an effect, the voltage seen by some parts of the insulation system may exceed the Partial Discharge Inception Voltage (PDIV) stating localized partial discharges activity. The insulation system in low-voltage machines (called type I) is based almost entirely on polymer materials, which are not able to support partial discharge activity throughout their lives. Due to the use of frequency inverters especially the primary insulation of the magnet wire is endangered in comparison with system-powered machines. As a result this is often the weakest link of the insulation system leading to a premature breakdown of the machine. The aim of this thesis is to investigate and analyze the aging process of the enameled wire exposed to different factors and to propose a method allowing to predict their lifespans in given conditions. This study introduces a prediction based on the Design of Experiments method and the statistical Weibull distribution. Thanks to the model obtained with short multi-stress (temperature, voltage, frequency) aging tests, it is possible to predict the results of significantly longer ones. Moreover, the adapted methodology is proposed that allows to predict the scatter of the long tests basing on the short-time results dispersion. The predictions are compared with the experimental data in order to prove the model accuracy

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Almeida, Gisele Madeira Duboc de. ""Rhodotorula spp.isoladas de hemocultura no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo: características clínicas e microbiológicas"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/5/5144/tde-03042006-150649/.

Texto completo

Resumen

Foi realizado um estudo para verificar a ocorrência de leveduras do gênero Rhodotorula, em hemocultura por um período de 8 anos. Os pacientes identificados foram descritos clinicamente segundo variáveis de interesse incluindo dados sobre terapêutica e desfecho. Determinou-se também as concentrações inibitórias mínimas de 20 cepas frente a diferentes antifúngicos de acordo com NCCLS e EUCAST. Realizou-se tipagem molecular através da cariotipagem eletroforética em campo pulsátil A study was conducted to verify the frequency of occurrence of Rhodotorula spp. from blood cultures over an 8-year period, clinically and microbiologically characterizing patients affected, including data regarding antifungal treatment and outcome. The minimal inhibitory concentrations of antifungal agents were determined against 20 isolates. Molecular typing of the strains were performed using pulsed field gel electrophoresis method

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "Isolation methods"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros