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Dissertations / Theses on the topic 'Hyphenated'
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Percopo, Luisa Andreana Maria. "Hyphenated selves : Australian ethnic minority autobiography." Thesis, King's College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445243.
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Galvani, Viola <1989>. "Hyphenated identities in Mordecai Richler's Novels." Master's Degree Thesis, Università Ca' Foscari Venezia, 2013. http://hdl.handle.net/10579/3557.
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Despite many traditional aspects in Mordecai Richler’s novels, mostly concerning form and structure, his protagonists are expressions of a determined place and time, notably post II-World-War Montreal, and they well embody the status of ‘hyphenated identities’. The case of Montreal is special in this sense, since Jewish Canadians represent a considerably vast minority of the population, and they are evident examples of ‘hyphenated identities’ due to their origins and culture. Identity can be explored in relation to place and time, which forcedly change, and in a larger sense in a geographical and temporal cyclic movement, in the attempt to build an identity more than forcing it into a definition. Finally, the rejection of a fixed identity can also be seen as the attempt to escape frames and strict definitions, more than reducing it to a simple lack.
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Airiau, Christian Y. "Application of chemometrics to hyphenated liquid chromatography." Thesis, University of Bristol, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392922.
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Hallissy, Margaret. "Reading Irish-American fiction : the hyphenated self /." Basingstoke : Palgrave Macmillan, 2006. http://catalogue.bnf.fr/ark:/12148/cb401445882.
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Jonsson, Pär. "Multivariate processing and modelling of hyphenated metabolite data." Doctoral thesis, Umeå universitet, Kemi, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-663.
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One trend in the ‘omics’ sciences is the generation of increasing amounts of data, describing complex biological samples. To cope with this and facilitate progress towards reliable diagnostic tools, it is crucial to develop methods for extracting representative and predictive information. In global metabolite analysis (metabolomics and metabonomics) NMR, GC/MS and LC/MS are the main platforms for data generation. Multivariate projection methods (e.g. PCA, PLS and O-PLS) have been recognized as efficient tools for data analysis within subjects such as biology and chemistry due to their ability to provide interpretable models based on many, correlated variables. In global metabolite analysis, these methods have been successfully applied in areas such as toxicology, disease diagnosis and plant functional genomics. This thesis describes the development of processing methods for the unbiased extraction of representative and predictive information from metabolic GC/MS and LC/MS data characterizing biofluids, e.g. plant extracts, urine and blood plasma. In order to allow the multivariate projections to detect and highlight differences between samples, one requirement of the processing methods is that they must extract a common set of descriptors from all samples and still retain the metabolically relevant information in the data. In Papers I and II this was done by applying a hierarchical multivariate compression approach to both GC/MS and LC/MS data. In the study described in Paper III a hierarchical multivariate curve resolution strategy (H-MCR) was developed for simultaneously resolving multiple GC/MS samples into pure profiles. In Paper IV the H-MCR method was applied to a drug toxicity study in rats, where the method’s potential for biomarker detection and identification was exemplified. Finally, the H-MCR method was extended, as described in Paper V, allowing independent samples to be processed and predicted using a model based on an existing set of representative samples. The fact that these processing methods proved to be valid for predicting the properties of new independent samples indicates that it is now possible for global metabolite analysis to be extended beyond isolated studies. In addition, the results facilitate high through-put analysis, because predicting the nature of samples is rapid compared to the actual processing. In summary this research highlights the possibilities for using global metabolite analysis in diagnosis.
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Soloway, Jason A. "Negotiating a hyphenated identity, three Jewish-Canadian writers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ39887.pdf.
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Jonsson, Pär. "Multivariate processing and modelling of hyphenated metabolite data /." Umeå : Dept. of Chemistry, Umeå University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-663.
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Giacomuzzi, Andrea. "Constructing An Hyphenated Society: Women, Ethnocentrism, and Migration." Diss., The University of Arizona, 2005. http://hdl.handle.net/10150/195873.
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In this dissertation I explore the relationship between women, the state, and religious institutions in western Austria--the most conservative part of the country. The fall of the Iron Curtain triggered widespread fears of massive migration flows from Eastern Europe, and created strong sentiments against migrants, especially those from the East and South and led to a rise in ethnocentrism and xenophobia. Turks, who comprise the largest migrant population, are especially vulnerable to the resulting discriminatory practices and attitudes.The questions I posed focused on how Turkish women who have arrived since the economic boom of the 1980s, their children born in Austria, and women of pre-WWII Austrian ancestry deal with the challenges integration brings. Further, I examine the effect patriarchal, elitist discourse has on both Austrian and Turkish migrant women's self-perception, sociopolitical status and their worldviews.
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Wanekaya, Adam. "Novel hyphenated technologies for sensing, separation and sample treatment." Diss., Online access via UMI:, 2005. http://wwwlib.umi.com/cr/binghamton/main/.
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Jones, Mary-Ellen. "It's an Irish Lullaby: One Story of Hyphenated American Culture." VCU Scholars Compass, 2006. http://hdl.handle.net/10156/1911.
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Jordan, Sheri Lynne. "Hyphenated fourier transform infrared spectrometry : techniques for separations and analysis /." Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-08282003-155254/.
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Kapoore, Rahul Vijay. "Mass spectrometry based hyphenated techniques for microalgal and mammalian metabolomics." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/8234/.
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In metabolomics, the analytical challenge is to capture the chemical diversity of the metabolome. With the current technologies only a portion of the metabolome can be analysed. As a result there is a drive to direct significant analytical efforts towards capturing the metabolome or changes in the metabolome reliably and reproducibly in biological systems. Apart from analytical challenges, the challenges also include development of appropriate methodologies to quench and extract metabolites which is a crucial parameter in sample preparation and is required to achieve an accurate representation of phenotype. This thesis focuses on addressing both the challenges in mammalian and microalgal metabolomics. Metabolomics in cancer research is gaining momentum as a tool to understand the molecular mechanism of disease progression and for the identification of specific biomarkers which may assist distinguishing between normal, benign and metastatic cancer states. In our first investigation we developed GC-MS based modified direct cell scraping, bead harvesting and LN2 methods for harvesting three adherently grown mammalian cell lines (two breast cancer cell lines MDA-MB 436, MCF7 and an endothelial cell line HMEC1) which provided rapid and reliable route with three fold improved metabolome coverage and reduced the artifacts due to metabolome leakage compared to conventional methods. Later optimized treatments were employed and the influence of various washing and quenching solvents (buffered/unbuffered) on metabolite leakage was investigated for metastatic cancer cell line MDA-MB-231. This identified one washing step with PBS followed by quenching with 60% methanol (buffered with HEPES) as the best washing and quenching solvents. Further validation and comparison of proposed workflows for metabolomic study of two metastatic TNBC cell lines (MDA-MB-231 and MDA-MB-436) resulted in recovery of 154 unique metabolites and demonstrated the robustness and reliability of these methods in pathway based analysis in cancer. In case of GC-MS based microalgal metabolomics, with comprehensive evaluation of selected quenching and extraction methods in model microalga C. reinhardtii, we have successfully demonstrated that the choice of quenching and extraction solvents have significant impact on recovery of different classes of metabolites. Our results clearly indicate that 60% methanol (buffered with HEPES) and 25 % aqueous methanol are the best suited quenching and extraction solvent respectively for untargeted metabolomic analysis of C. reinhardtii, as the highest number of metabolites belonging to various chemical classes were recovered with good intensities and reproducibilities with this miniaturized proposed method compared to other evaluated methods. Later impact of various stages involved in biodiesel production workflow from microalga on recovery of biodiesel was assessed in three microalgal species namely C. reinhardtii, D. salina and N. salina. Within which we have developed an optimized GC-FID method and miniaturized direct TE method for quantification of fatty acids, which can be applied to a small amount of biomass and saves tremendous amounts of time, solvents and reagents required, is less expensive and uses environment friendly solvents making it more suitable for sustainable large scale production. In our final investigation, we directed our efforts towards preliminary optimization and comparative analysis of HILIC and IP-RP-HPLC based separation for the retention and separation of specific metabolites classes. This identified HILIC as the best available column till date for untargeted metabolomic studies. The descriptive understanding gained from each of these investigations provides greater insight into biology of mammalian and algal systems by improving the metabolome coverage for various metabolite classes. These insights illustrating the underlying molecular pathways involved in respective biology's, will help scientific communities in identifying as-of-yet-missing reactions in the metabolic network. In addition these insights will surely help in generating many hypothesis based investigations in microalgal and cancer community.
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Zomer, Simeone. "Application of chemometrics for feature extraction and pattern recognition in hyphenated chromatography." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432960.
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Gerislioglu, Selim. "Microstructure Characterization of Polymers and Polymer-Protein Bioconjugates by Hyphenated Mass Spectrometry." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1534269781343128.
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Protti, Michele <1986>. "Hyphenated Approaches for the Analysis of Bioactive Natural Compounds in Complex Matrices." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7520/1/Tesi_PhD_Michele_Protti.pdf.
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Plants, animals and micro-organisms represent a reservoir of natural products, the so called “natural source-derived compounds”. This is particularly true for the plant kingdom, as it offers a variety of species still used as remedies for several diseases in many parts of the world. Nevertheless, the bioactive potential of many plant species remains largely unexplored. Thus, biodiversity represents an unlimited source of chemical entities with potential beneficial effects on human health. These compounds are usually secondary metabolites often present in low quantity in plant material and their extraction, purification and quantitation still remain a great challenge for analytical scientists.
The research activity carried out during these three years of PhD Programme was focused on the development, validation and application of original methods aimed at the quali-quantitative analysis of compounds with potential bioactive interest in plant matrices, foods, drinks and related products, as well as the analytical screening of plant by-products from cosmetic manufacture. Bioactive substances, belonging to the classes of polyphenols, aminoacids, coumarins, triterpenes and phytohormones, have been investigated as authenticity markers, in order to identify high quality products and to valorise niche products. The study regarded herbs (Argania spinosa), fruits (Citrus × myrtifolia, Punica granatum) and berries (Myrtus communis) mainly used as folk medicines for their broad spectrum of supposed pharmacological and therapeutic effects. The analytical methods developed within this study are based on high performance liquid chromatography and ultra-high performance liquid chromatography coupled to spectrofluorometric detection, triple quadrupole and high-resolution triple quadrupole mass spectrometry (HPLC-F, LC-MS/MS and UHPLC-HRMS). Significant efforts have been put also into the development and optimisation of miniaturised sample pretreatment strategies, such as micro-solid phase extraction (µSPE) and micro-extraction by packed sorbent (MEPS), able to purify complex matrices of natural origin (whole fruits, fruit parts, leaves and their extracts) and derived commercial products.
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Protti, Michele <1986>. "Hyphenated Approaches for the Analysis of Bioactive Natural Compounds in Complex Matrices." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7520/.
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Plants, animals and micro-organisms represent a reservoir of natural products, the so called “natural source-derived compounds”. This is particularly true for the plant kingdom, as it offers a variety of species still used as remedies for several diseases in many parts of the world. Nevertheless, the bioactive potential of many plant species remains largely unexplored. Thus, biodiversity represents an unlimited source of chemical entities with potential beneficial effects on human health. These compounds are usually secondary metabolites often present in low quantity in plant material and their extraction, purification and quantitation still remain a great challenge for analytical scientists.
The research activity carried out during these three years of PhD Programme was focused on the development, validation and application of original methods aimed at the quali-quantitative analysis of compounds with potential bioactive interest in plant matrices, foods, drinks and related products, as well as the analytical screening of plant by-products from cosmetic manufacture. Bioactive substances, belonging to the classes of polyphenols, aminoacids, coumarins, triterpenes and phytohormones, have been investigated as authenticity markers, in order to identify high quality products and to valorise niche products. The study regarded herbs (Argania spinosa), fruits (Citrus × myrtifolia, Punica granatum) and berries (Myrtus communis) mainly used as folk medicines for their broad spectrum of supposed pharmacological and therapeutic effects. The analytical methods developed within this study are based on high performance liquid chromatography and ultra-high performance liquid chromatography coupled to spectrofluorometric detection, triple quadrupole and high-resolution triple quadrupole mass spectrometry (HPLC-F, LC-MS/MS and UHPLC-HRMS). Significant efforts have been put also into the development and optimisation of miniaturised sample pretreatment strategies, such as micro-solid phase extraction (µSPE) and micro-extraction by packed sorbent (MEPS), able to purify complex matrices of natural origin (whole fruits, fruit parts, leaves and their extracts) and derived commercial products.
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Oller, Moreno Sergio. "Data processing for Life Sciences measurements with hyphenated Gas Chromatography-Ion Mobility Spectrometry." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/523539.
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Recent progress in analytical chemistry instrumentation has increased the amount of data available for analysis. This progress has been encompassed by computational improvements, that have enabled new possibilities to analyze larger amounts of data. These two factors have allowed to analyze more complex samples in multiple life science fields, such as biology, medicine, pharmacology, or food science.
One of the techniques that has benefited from these improvements is Gas Chromatography - Ion Mobility Spectrometry (GC-IMS). This technique is useful for the detection of Volatile Organic Compounds (VOCs) in complex samples. Ion Mobility Spectrometry is an analytical technique for characterizing chemical substances based on the velocity of gas-phase ions in an electric field. It is able to detect trace levels of volatile chemicals reaching for some analytes ppb concentrations. While the instrument has moderate selectivity it is very fast in the analysis, as an ion mobility spectrum can be acquired in tenths of milliseconds. As it operates at ambient pressure, it is found not only as laboratory instrumentation but also in-site, to perform screening applications. For instance it is often used in airports for the detection of drugs and explosives. To enhance the selectivity of the IMS, especially for the analysis of complex samples, a gas chromatograph can be used for sample pre-separation at the expense of the length of the analysis.
While there is better instrumentation and more computational power, better algorithms are still needed to exploit and extract all the information present in the samples. In particular, GC-IMS has not received much attention compared to other analytical techniques. In this work we address some of the data analysis issues for GC-IMS: With respect to the pre-processing, we explore several baseline estimation methods and we suggest a variation of Asymmetric Least Squares, a popular baseline estimation technique, that is able to cope with signals that present large peaks or large dynamic range. This baseline estimation method is used in Gas Chromatography - Mass Spectrometry signals as well, as it suits both techniques. Furthermore, we also characterize spectral misalignments in a several months long study, and propose an alignment method based on monotonic cubic splines for its correction. Based on the misalignment characterization we propose an optimal time span between consecutive calibrant samples.
We the explore the usage of Multivariate Curve Resolution methods for the deconvolution of overlapped peaks and their extraction into pure components. We propose the use of a sliding window in the retention time axis to extract the pure components from smaller windows. The pure components are tracked through the windows. This approach is able to extract analytes with lower response with respect to MCR, compounds that have a low variance in the overall matrix
Finally we apply some of these developments to real world applications, on a dataset for the prevention of fraud and quality control in the classification of olive oils, measured with GC-IMS, and on data for biomarker discovery of prostate cancer by analyzing the headspace of urine samples with a GC-MS instrument.<br>Els avenços recents en instrumentació química i el progrés en les capacitats computacionals obren noves possibilitats per l’anàlisi de dades provinents de diversos camps en l’àmbit de les ciències de la vida, com la biologia, la medicina o la ciència de l’alimentació.
Una de les tècniques que s’ha beneficiat d’aquests avenços és la cromatografia de gasos – espectrometria de mobilitat d’ions (GC-IMS). Aquesta tècnica és útil per detectar compostos orgànics volàtils en mostres complexes. L’IMS és una tècnica analítica per caracteritzar substàncies químiques basada en la velocitat d’ions en fase gasosa en un camp elèctric, capaç de detectar traces d’alguns volàtils en concentracions de ppb ràpidament. Per augmentar-ne la selectivitat, un cromatògraf de gasos pot emprar-se per pre-separar la mostra, a expenses de la durada de l’anàlisi.
Tot i disposar de millores en la instrumentació i més poder computacional, calen millors algoritmes per extreure tota la informació de les mostres. En particular, GC-IMS no ha rebut molta atenció en comparació amb altres tècniques analítiques. En aquest treball, tractem alguns problemes de l’anàlisi de dades de GC-IMS: Pel que fa al pre-processat, explorem algoritmes d’estimació de la línia de base i en proposem una millora, adaptada a les necessitats de l’instrument. Aquest algoritme també s’utilitza en mostres de cromatografia de gasos espectrometria de masses (GC-MS), en tant que s’adapta correctament a ambdues tècniques. Caracteritzem els desalineaments espectrals que es produeixen en un estudi de diversos mesos de durada, i proposem un mètode d’alineat basat en splines cúbics monotònics per a la seva correcció i un interval de temps òptim entre dues mostres calibrants.
Explorem l’ús de mètodes de resolució multivariant de corbes (MCR) per a la deconvolució de pics solapats i la seva extracció en components purs. Proposem l’ús d’una finestra mòbil en el temps de retenció. Aquesta millora permet extreure més informació d’analits.
Finalment utilitzem alguns d’aquests desenvolupaments a dues aplicacions: la prevenció de frau en la classificació d’olis d’oliva, mesurada amb GC-IMS i la cerca de biomarcadors de càncer de pròstata en volàtils de la orina, feta amb GC-MS.
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Bailey, Nigel John Collingwood. "Development and application of hyphenated NMR techniques to the study of agrochemical metabolism." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394243.
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Wangkarn, Sunanta. "Development of hyphenated analytical techniques for arsenic speciation in environmental and biological matrices." Thesis, Birkbeck (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342227.
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Dixon, Sarah. "Application of chemometric methods to biological, simulated and forensic hyphenated mass spectrometry datasets." Thesis, University of Bristol, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445812.
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Mingboupha, Nathalie. "Hyphenated-Chinese in China : Western-born second generation overseas Chinese's ethnic 'return' migration." Thesis, University of Sheffield, 2019. http://etheses.whiterose.ac.uk/23056/.
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This thesis focuses on Western-born second generation overseas Chinese who "return" migrate to China, their ancestral homeland. Inscribed within the larger social processes and dynamics of Chinese contemporary society, this research aims to understand how their "homecoming" and socio-cultural integration experiences in the parental homeland's society leads to the re-evaluation of their ethno-cultural identity(ies) and ethno-national attachments. My research uses a qualitatively-driven multimethod design. Data collection primarily consisted of semi-structured in-depth interviews with 58 ethnic remigrants in Beijing and Shanghai, as well as a variety of document analyses. Guided by the concept of social anchoring, this study thus sheds light on the role of ethnicity in channeling migration and in restructuring the remigrants' identities in their ancestral country. By examining how this group of highly-skilled migrants' definitions of self and home evolve along with their transition from being a racial minority in their birth country to a cultural minority in their ethnic homeland, this thesis uncovers the multi-layered experiences of socio-cultural integration (and lack thereof) that trigger unexpected identity questioning, as evidenced by remigrants' social networks and every day interactions in the homeland. By exploring their integration experiences and overall migration journey, I find that many are in fact paradoxically integrated in China, causing them to experience various forms of emotional in-betweenness and double disconnection challenging the boundaries of their ethno-cultural identities.
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Magnusson, Evelina. "Describing scent : On the translation of hyphenated premodifiers in a text about perfume." Thesis, Linnéuniversitetet, Institutionen för språk (SPR), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-106973.
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This small-scale study examines the translation of a text about perfumes, focusing on how hyphenated premodifiers in the English source text were translated into Swedish. A quantitative analysis was carried out, where the various premodifying structures present in the source text were identified and categorized according to their individual constituents and frequencies of the various categories were calculated. A similar analysis was also performed regarding the corresponding structures found in the Swedish target text. The results were then compared to and contrasted with other recent studies. In the qualitative analysis, individual examples from the text were analysed more in depth, and the consequences of the translation choices made were discussed. The results demonstrated that English hyphenated premodifiers showed a great deal of structural variety. The most frequent structures were nouns occurring in the left-hand position and ed-participles occurring the right-hand position. A large majority of the hyphenated premodifiers were short, with only 5.5% consisting of three words or more. The results also showed that the most frequent corresponding structure in the Swedish target text were compound adjectives, which comprised 48.1% of all examples. The results of the qualitative analysis pointed at a tendency towards explication, especially when hyphenated premodifiers were restructured to postmodifying phrases and clauses. Furthermore, a tendency to simplify the hyphenated modifiers during the translation process was noted, especially when translating longer, phrasal modifiers. It was noted that many hyphenated premodifiers in the ST were metaphorical in nature. This was sometimes, but not always, also the case in the corresponding TT phrases.
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Hellgeth, John William. "Assessment of coal liquefaction behavior through product characterization with hyphenated chromatographic/spectroscopic methods." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/49792.
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Shapiro, Jonathan Chira. "Hyphenated Japan: Cross-examining the Self/Other dichotomy in Ainu-Japanese material culture." Oberlin College Honors Theses / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1494762526392067.
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Williams, Samuel Thomas. "Analysis of erythropoietin for anti-doping purposes with a focus on hyphenated techniques." Thesis, King's College London (University of London), 2014. https://kclpure.kcl.ac.uk/portal/en/theses/analysis-of-erythropoietin-for-antidoping-purposes-with-a-focus-on-hyphenated-techniques(8b6d26e7-a9c5-4d5a-9e3a-f32be79939e2).html.
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To improve detection of the misuse of erythropoietin (EPO) for performance enhancing purposes, this PhD examined ways to improve recovery and preanalysis concentration of EPO from urine. It also looked at ways to enhance the signal in liquid chromatography tandem mass spectrometry of the acidic glycopeptides from digested EPO, and at distinguishing between recombinant EPO and human urinary EPO based on differences in their glycosylation. Due to a shortage of supply of available analytical standards, model glycoproteins were frequently used in place of endogenous EPO. Immunoextraction with magnetic beads effectively recovered EPO from urine which had been filtered to remove large proteins, but was unsuccessful from unfiltered urine, suggesting more research into the right choice of antibody was needed. The specific and reversible binding of boronic acids to cis-diol groups found in the glycan groups of glycoproteins was investigated as a device for the selective binding of EPO. Attempts were made to functionalise mesoporous silica for use as a column packing material. Although there was evidence that at least one method of functionalisation was successful, the use of this silica to extract glycoproteins and glycopeptides was not. Signal enhancement through the introduction of ‘superchargers’ into LC solvents was investigated. This was effective with small molecules, and also improved detection of sialylated glycopeptides. The results do not fit entirely with current models of how superchargers exert their effect, suggesting they are incomplete. Finally, the cleavage, digestion and derivatisation of N-glycans to identify bisected and non-bisected structures as a way to discriminate between rEPO and huEPO was examined. Samples were analysed using LC-MS and CE-LIF, and although much of the work was carried out using a model glycoprotein, there is some evidence that the approach may be capable of discriminating between artificial and endogenous EPO at the levels found in anti-doping samples.
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Timischl, Birgit. "Hyphenated mass spectrometric methods for quantitative metabolomics in E. coli and human cells." kostenfrei, 2008. http://www.opus-bayern.de/uni-regensburg/volltexte/2008/1028/.
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Prazen, Bryan J. "Development of high speed hyphenated chromatographic analyzers and second order data analysis techniques /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11550.
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Alasonati, Enrica. "Development of a hyphenated analytical methodology for the fractionation and characterization of environmental colloids /." Lausanne : EPFL, 2009. http://library.epfl.ch/theses/?nr=4325.
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Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 4325 (2009), Faculté de l'environnement naturel, architectural et construit ENAC, Programme doctoral Environnement, Institut des sciences et technologies de l'environnement ISTE (Groupe Slaveykova GR-SLV). Dir.: Vera Slaveykova-Startcheva.
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Chu, Eileen. "Asian-Australian hyphenated identification: Self and other perceptions and their implications for intergroup relations." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15987.
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Some minorities identify as bicultural seeing both their ethnic and national cultural identities as important to their self-concept. Importantly, recent research and theory is suggesting that a bicultural identity is not always captured by these existing identity categories. Alternatively, some minorities identify with an additional hyphenated identity (e.g., Chinese-Australian). This identity, however, may not always be acknowledged by majority individuals. This thesis explores ways in which such misrecognitions can be addressed within Australian society by i) exploring the relevance of hyphenated identification amongst Asian-Australians; ii) evaluating the extent to which other's acknowledgement of Asian-Australians’ hyphenated identity has a positive impact on the self and on outgroup attitudes towards majority Anglo-Australians; and iii) how attitudes regarding the representation of Australian national identity can be changed to become more inclusive of minorities’ identities through adopting dual-identity representations of Australian national identity. Five studies were designed to address these aims. In conclusion, the thesis found evidence to support the relevance of hyphenated identities for minority Asian-Australians’ sense of self as well as preliminary evidence to suggest that others' recognition of Asian-Australians' hyphenated identities, may be important for perceived acceptance from others. Social-cultural factors within Australian society, however, may act as barriers against the recognition of hyphenated identities. This thesis contributes to research in acculturation, biculturalism, and intergroup relations by underscoring the importance of more holistic intervention approaches, which include minorities' perceptions of self and perspectives during intergroup interactions. Thus, these findings will have practical implications for improving the quality of group relations in an ever increasing multicultural Australian society.
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Eyres, Graham Terence, and n/a. "Determination of character-impact odorants in hop essential oils using hyphenated techniques in gas chromatography." University of Otago. Department of Food Science, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080125.143442.
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Hops (Humulus lupulus L.) are an indispensable component of beer, with the essential oil responsible for imparting distinctive odour and aroma characteristics to beer. However, not all character-impact odorants in hop essential oil have been identified and hop aroma in beer is still not completely understood. The composition of hop essential oil is very complex with 485 compounds currently identified in the literature, and recent research suggests that up to 1000 compounds may actually be present. Only a certain number will be present at concentrations above threshold and make a direct contribution to the odour of the oil. In addition, many important odorants are only present at trace concentrations. Gas chromatography-olfactometry (GC-O) using human assessors is the best way to locate potent odorants and facilitate their identification.
A novel methodology was developed to identify the character-impact odorants in hop essential oil samples using hyphenated techniques in gas chromatography. GC-O was used to locate odour active compounds and determine relative importance using CharmAnalysis[TM] according to the odour potency principle. Due to the chemical complexity of the samples, considerable co-elution of peaks occurs during single column gas chromatography (1DGC), making the detection and identification of character-impact odorants challenging. Therefore, comprehensive two-dimensional gas chromatography (GCxGC) combined with time-of-flight mass spectrometry (TOFMS) was used to resolve and identify compounds eluting in the odour active regions.
The methodology was developed in a case study on coriander (Coriandrum sativum) and wild coriander (Eryngium foetidum) leaf essential oils. During GC-O analysis of these samples it was recognised that odour active regions frequently coincide with several co-eluting compounds. To address this, a heart-cut multidimensional gas chromatography-olfactometry (MDGC-O) instrument was developed to resolve these 'co-eluting odour clusters' and determine the compound(s) responsible for the odour perception.
The 'spicy' character of hops is considered to be a desirable attribute in beer associated with 'noble hop aroma'. However, the compounds responsible have yet to be adequately elucidated. This character was investigated using a commercial 'Spicy' fraction of hop essential oil, selectively enriched for monoterpene and sesquiterpene alcohols. The odour active compounds in (i) the spicy fractions and (ii) the whole essential oils of four different hop varieties were compared using the presented methodology.
A compound with an intense 'woody, cedarwood' odour was determined to be a potent, character-impact odorant in all samples. This odour coincided with a complex region of the chromatogram where up to thirteen compounds were co-eluting. The peak responsible for this odour was determined by (i) correlation of peak areas with odour potency (Charm) values and (ii) MDGC-O. The compound was tentatively identified by GCxGC-TOFMS as 14-hydroxy-β-caryophyllene, which has not previously been reported as an odorant in hop essential oil. It was concluded that this compound and other 'woody, cedarwood' odorants contributed to the 'spicy' character of the investigated hop samples. Compounds previously associated with noble hop aroma, notably caryophyllene oxide, humulene epoxides I and II, and humulenol II, did not contribute to the odour character of the hop samples.
Other potent odorants that were identified in the whole essential oil and spicy fractions of hops were: geraniol, linalool, β-ionone, eugenol, isovaleric acid, and β-damascenone. While myrcene was a moderately potent odorant in the whole hop essential oil samples, the abundant sesquiterpene hydrocarbons α-humulene, β-caryophyllene and β-farnesene did not significantly contribute to the odour character.
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Vetere, Alessandro [Verfasser], and Wolfgang [Akademischer Betreuer] Schrader. "Development of hyphenated techniques for the analysis of complex mixtures / Alessandro Vetere ; Betreuer: Wolfgang Schrader." Duisburg, 2017. http://d-nb.info/1138922633/34.
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Hiltunen, Nina. "The translation of cultural references and hyphenated premodifers in a travel guide about the Caribbean." Thesis, Linnéuniversitetet, Institutionen för språk (SPR), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-78138.
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This paper studies how cultural references and hyphenated premodifiers in an English travel guide about the Caribbean are translated into Swedish. The aim is to investigate what strategies that are used when translating cultural references, and why; as well as to see which grammatical structures that appear when translating hyphenated premodifiers from English to Swedish. The qualitative analysis focuses on how cultural references and hyphenated premodifiers are translated, the strategies/categories used, and the corresponding result. The quantitative analysis aims at summarizing what strategies or grammatical categories that are most commonly used in overcoming these translation issues. The results show that most hyphenated premodifiers are translated with another grammatical structure, namely through premodifying adjectives, without the use of hyphens. Regarding cultural references, equivalence, transference, and generalization were common strategies to convey the same content and sense to the new target readers, whereas the domesticating method together with communicative translation proved to be the most helpful methods.
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Lindblad, Cecilia. "Mass Tourism and the Environment : A Translation Study of Terminology, Metaphors and Hyphenated Premodifiers in Two Articles." Thesis, Linnaeus University, School of Language and Literature, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-6214.
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<p>The following essay is an analysis of a translation from English into Swedish of two articles concerning tourism, travelling and the environment. The language of the articles is expressive and rich in metaphors, which evokes images in the mind of the reader. The translation was performed with the aim to transfer this effect into the translated texts and the aspects to be examined in the analysis were chosen with this in mind.One of the three aspects to be examined is the use of metaphors and how they are translated into Swedish. Many of the metaphors bear reference to travelling and the environment which gives them a function of enforcing the message and engaging the reader in the text. In order to obtain the same effect in the Swedish translations several translation strategies had to be used.The second aspect to be examined is the terminology used within tourism and the environment. The environmental concern is a growing trend which inevitably influences the language and requires a new set of useful and understandable terms. This becomes clear when reading and translating the articles at hand. The environmental terms are fairly new and sometimes hard to distinguish. In this study focus is set on the translation strategies and the procedures used in order to find the Swedish equivalents of the terms in this context.The third aspect is the translation of hyphenated pre-modifiers. This aspect is particularly interesting, since the phenomenon is more or less unknown in Swedish. Of the fifteen hyphenated pre-modifiers in the source texts none were translated into hyphenated pre-modifiers in Swedish although five of them were translated into regular pre-modifiers. The analysis is based on the translation strategies applied and the comparison of syntactic structures of the expressions in English and Swedish.</p>
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LUPI, FRANCESCA. "Fungal populations and metabolism of fusarium mycotoxins in cereals: from occurrence to analysis by hyphenated analytical techniques." Doctoral thesis, Università di Foggia, 2017. http://hdl.handle.net/11369/361931.
Full textAbstract:
Il successo nella produzione di cereali, per quanto riguarda la contaminazione fungina durante
la fase pre-raccolta, è fortemente correlato alla valutazione del controllo qualità. Lo scopo di questa
ricerca è stato quello di studiare come lo zearalenone (ZEN), un metabolita secondario prodotto da
diverse specie di Fusarium, sia metabolizzato e modificato nei cereali, come ad esempio il grano e
l’orzo. Inoltre, abbiamo sviluppato e ottimizzato metodi analitici per l’identificazione di composti
organici volatili (VOC) prodotti dall’interazione tra due specie fungine tossigene selezionate (F.
graminearum e F. culmorum) e piante di frumento. L’identificazione di biomarcatori di infezione
precoce, all’interno di questi VOC, può contribuire a prevenire/ridurre le contaminazioni all’interno
della catena alimentare.
Per quanto riguarda la micotossina ZEN, sono stati eseguiti esperimenti “Time Course”. Il
grano e l’orzo sono stati trattati con ZEN. I campioni sono stati raccolti in tempi differenti e analizzati
con un sistema UHPLC accoppiato ad uno spettrometro di massa QTOF. Il metodo LC-MS è stato
ottimizzato per consentire un’analisi veloce, ma comunque in grado di separare i metaboliti target. Per
quanto riguarda i composti volatili, le piante di frumento sono state inoculate utilizzando sospensioni di
spore dei due funghi selezionati. Le analisi sono state effettuate in differenti fasi fenologiche di
crescita. I VOC sono stati campionati direttamente nello spazio di testa di foglie e spighe, mediante
microestrazione in fase solida, e analizzati mediante strumentazione GC-MS.
Quantità assolute di ZEN e dei suoi metaboliti possono essere riportati rispetto al tempo di
raccolta dopo il trattamento. Sulla base del recupero percentuale rispetto al punto zero, si è visto che la
maggioranza dello ZEN non è stata metabolizzata dalle piante. I principali prodotti di metabolizzazione
sono stati i glucosidi. Invece i dati ottenuti dalle analisi dei VOC sono stati elaborati utilizzando
approcci statistici, come la PCA (analisi dei componenti principali), che sottolineano differenze molto
importanti tra i campioni. In particolare la maggior parte dei VOC sono stati rilevati durante la
maturazione lattea. Tra le sostanze identificate, alcoli alifatici, aldeidi e chetoni sono stati i più
abbondanti. Questi composti hanno differenti vie di biosintesi.
Per quanto riguarda gli esperimenti “Time Course”, è possibile concludere che la maggior parte
dello ZEN rimane non metabolizzata, però abbiamo osservato alcuni glucosidi, in particolare nell’orzo,
il quale si è dimostrato più attivo nella produzione di glucosidi rispetto al grano. L’approccio
sviluppato nello studio dei volatili ha fornito risultati promettenti nel prevedere il potenziale della
formazione della tossina, individuando la presenza di entrambe le specie di Fusarium nelle fasi iniziali
della crescita fungina nelle cultivar di frumento.
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Sarthou, Sharron Eve. "Mediating the negative space : the role of the hyphenated self in the work of Edwidge Danticat /." Full text available from ProQuest UM Digital Dissertations, 2009. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=0&did=1913289461&SrchMode=1&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1278529129&clientId=22256.
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Tollbäck, Petter. "Large Volume Injection and Hyphenated Techniques for Gas Chromatographic Determination of PBDEs and Carbazoles in Air." Doctoral thesis, Stockholm University, Department of Analytical Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-367.
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<p>This thesis is based on studies in which the suitability of various gas chromatography (GC) injection techniques was examined for the determination of polybrominated diphenyl ethers (PBDEs) and carbazoles, two groups of compounds that are thermally labile and/or have high boiling-points. For such substances, it is essential to introduce the samples into the GC system in an appropriate way to avoid degradation and other potential problems. In addition, different types of gas chromatographic column system and mass spectrometric detectors were evaluated for the determination of PBDEs.</p><p>Conventional injectors, such as splitless, on-column and programmed temperature vaporizing (PTV) injectors were evaluated and optimized for determination of PBDEs. The results show on-column injection to be the best option, providing low discrimination and high precision. The splitless injector is commonly used for “dirty” samples. However, it is not suitable for determination of the high molecular weight congeners, since it tends to discriminate against them and promote their degradation, leading to poor precision and accuracy. The PTV injector appears to be a more suitable alternative. The use of liners reduces problems associated with potential interferents such as polar compounds and lipids and compared to the hot splitless injector, it provides gentler solvent evaporation, due to its temperature programming feature, leading to low discrimination and variance.</p><p>Increasing the injection volume from the conventional 1-3 µL to >50 µL offers two main benefits. Firstly, the overall detection and quantification limits are decreased, since the entire sample extract can be injected into the GC system. Secondly, large volume injections enable hyphenation of preceding techniques such as liquid chromatography (LC), solid phase extraction and other kinds of extraction. Large-volume injections were utilized and optimized in the studies included in this thesis.</p><p>With a loop-type injector/interface large sample volumes can be injected on-column providing low risk of discrimination against compounds with low volatility. This injector was used for the determination of PBDEs in air and as an interface for the determination of carbazoles by LC-GC. Peak distortion is a frequently encountered problem associated with this type of injector that was addressed and solved during the work underlying this thesis.</p><p>The PTV can be used as a large volume injector, in so-called solvent vent mode. This technique was evaluated for the determination of PBDEs and as an interface for coupling dynamic sonication-assisted solvent extraction online to GC. The results show that careful optimization of the injection parameters is required, but also that the PTV is robust and yields reproducible results.</p><p>PBDEs are commonly detected using mass spectrometry in electron capture negative ionization (ECNI) mode, monitoring bromine ions (m/z 79 and 81). The mass spectrometric properties of the fully brominated diphenyl ether, BDE-209, have been investigated. A high molecular weight fragment at m/z 486/488 enables the use of 13C-labeled BDE-209 as an internal surrogate standard.</p>
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Co, Michelle. "Pressurised Fluid Extraction of Bioactive Species in Tree Barks : Analysis using Hyphenated Electrochemical Mass Spectrometric Detection." Doctoral thesis, Uppsala universitet, Analytisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-133264.
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Analytical chemistry has developed throughout time to meet current needs. At present, the interest in biorefinery is growing, due to environmental awareness and the depletion of fossil resources. Biomass from agricultural and forestry industries has proven to be excellent raw material for different processes. Biorefinering valuable species such as bioactive species from biomass, without compromising the primary process of the biomass is highly desirable. Pressurised fluid extraction (PFE) using water and ethanol as a solvent was developed for extracting betulin from birch (Betula pendula) bark. Apart from betulin, stilbene glucosides such as astringin, isorhapontin and picied were also extracted from spruce (Picea abies) using PFE. PFE is an advanced technique that extracts at temperatures above the solvent’s atmospheric boiling point. The applied pressure in PFE is mainly to maintain the liquid state of the extraction solvent. Parameters such as type of solvent, temperature, and time affect the extraction selectivity and efficiency. Therefore it is necessary to comprehend these parameters in order to optimise extraction. The DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to determine the antioxidant capacity and activity of the obtained bioactive species. The results showed high antioxidant capacity in bioactive species that were extracted at an elevated temperature, 180°C. Extraction and degradation occur simultaneously during the extraction. Hence, it is crucial to separate these two processes in order to obtain the actual value. An online hyphenated system of chromatographic separation electrochemical mass spectrometric detection was developed (LC-DAD-ECD-MS/MS). The electrochemical detector facilitates real-time monitoring of the antioxidant capacity and activity of each antioxidant and its oxidation products. This developed LC-DAD-ECD-MS/MS method enabled rapid screening of antioxidants and created a fingerprint map for their oxidation products. Characterisation and molecular elucidation of bioactive species were also performed. Degradation of bioactive species was investigated with the said online system and birch bark extract was compared with birch bark extracts that were hydrothermally treated. The obtained results showed some degradation of antioxidants at 180°C. In summary, the aim of this thesis was to develop analytical methods integrated with sustainable chemistry for extraction of bioactive species in biomass from the forestry industry. A novel online system using selective and sensitive detectors such as diode-array, electrochemical, and tandem mass spectrometry was developed to rapidly determine the antioxidant capacity and activity of antioxidants. Furthermore, tandem mass spectrometry enables identification of unknown bioactive species without the need of reference samples.<br>Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 719
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Tollbäck, Petter. "Large volume injection and hyphenated techniques for gas chromatographic determination of PBDEs and carbazoles in air /." Stockholm : Department of Analytical Chemistry, Stockholm University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-367.
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Scarfe, Graeme Bryan. "The in vivo metabolism of substituted anilines and acetanilides in rat using hyphenated NMR spectroscopic techniques." Thesis, Birkbeck (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325321.
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Gray, Christopher. "Comprehensive stereochemical sequencing of carbohydrates and characterisation of their binding partners using hyphenated mass spectrometry methods." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/comprehensive-stereochemical-sequencing-of-carbohydrates-and-characterisation-oftheir-binding-partners-using-hyphenated-mass-spectrometry-methods(0f606678-b7d1-4a5c-817a-fff2b9fab90a).html.
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Glycans and their conjugates form the largest and most diverse class of biological molecules found within nature. These glycosides are vital for numerous cellular functions including recognition events, protein stabilisation and energy storage, to name a few. Additionally, abnormalities within these structures are associated with a wide range of disease states. As a result, robust analytical techniques capable of in depth characterisation of carbohydrates and their binding partners are required. Currently, liquid chromatography coupled with tandem mass spectrometry (MS2) is the 'gold standard' for characterising these species. However there are inherent challenges for 'sequencing' carbohydrates given that most structures are diastereomeric. As a result MS alone is insufficient to fully elucidate all stereochemical and often regiochemical information and alternative analytical techniques have inherent issues meaning that they are not suitable for medium/high throughput analysis. To facilitate elucidation of these structures, ion mobility spectrometry (IMS) has been used in-line with MS2. IMS of mono- and di-saccharide product ions generate by collision-induced dissociation (CID) of various glycans and their conjugates enables unambiguous identification of the monomer and the regio-/stereo-chemistry of the glycosidic bond, independent of the precursor structure. Also, given the prominence of glycans in biological recognition events, high-throughput techniques capable of elucidating and characterising carbohydrate to glycan-binding protein (GBP) interactions are highly sought after. Historically, (micro)array strategies are employed to screen large numbers of biological interactions, with detection conventionally achieved with fluorescent tagging. The major disadvantage of this approach is the requirement of a labelling step to facilitate detection of glycan-GBP binding. MS offers the ability to unambiguously identify GBPs when combined with routine bottom-up proteomics strategies, namely on-chip proteolysis followed by mass fingerprinting and MS2 analysis and subsequent comparison to protein databases. It is anticipated that these methodologies developed throughout these studies, both for carbohydrate sequencing and the characterisation of glycan-binding proteins, will greatly add to the Glycomics toolbox.
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Powley, Stephanie Louise. "The quantitation of therapeutic olingonucleotides and their impurities analysed using hyphenated liquid chromatography and mass spectrometry." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422228/.
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As demand for therapeutic oligonucleotide drugs to treat a wider range of conditions increases, there is a requirement for a robust method for the quantitation of the impurities within a drug product. The development of a method that can be employed across all laboratories, regardless of the Liquid chromatography – Mass spectrometry instrumentation used, is highly desirable to ensure consistency of testing and to confirm inter-batch variation. Factors influencing the reliability of quantitation have been investigated, including mobile phase additives, mass analyser type and in-source collision-induced dissociation voltage. Strategies for quantitating the data collected have also been considered and compared. The effect of the oligonucleotide sequence on the level of in-source fragmentation has been observed and discussed. Recommendations are made for the most appropriate mobile phase reagents, mass analyser type and method of quantitation to be used to allow the development of an analytical method for use across laboratories to accurately and precisely quantitate therapeutic oligonucleotides and their impurities.
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Harris, Dee. "Design and development of a hyphenated technique for monitoring the cure of epoxy-amine resin systems." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/2872/.
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The main focus of the current study was to design, construct and evaluate a common platform to enable the integration of multiple sensing systems for cure monitoring. An Abbe refractometer was selected to house a custom-made cell which accommodated the following optical sensors: (i) Fresnel reflection sensor; (ii) near-infrared transmission sensor; (iii) evanescent wave sensor; and (iv) fibre Bragg grating sensor. The cell was designed such that it was also possible to simultaneously acquire conventional refractive index data during the cross-linking process. Thus, the cross-correlation of data on refractive index, cross-linking kinetics, strain and temperature was facilitated. It was found that the trends observed in the qualitative (intensity-based refractive index monitoring via the Fresnel reflection sensor) and quantitative (optical fibre-based transmission FTIR spectroscopy) approaches were similar during the cure of common thermosetting resin systems. Furthermore, for the first time, S-2 glass® fibres were used to obtain evanescent wave spectra during cross-linking, and excellent correlation was observed with the transmission FTIR spectral data. Fibre Bragg grating sensors were used to infer the magnitude of the residual fabrication strain. Excellent correlation was observed between the refractive index data generated using the Abbe refractometer and Fresnel reflection sensor.
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Wozniak, Casimir J. "Hyphenated Catholicism : a study of the role of the Polish-American model of Church : 1890-1908 /." San Francisco (Calif.) : Catholic scholars press, 1998. http://catalogue.bnf.fr/ark:/12148/cb388341310.
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Delmotte, Nathanaël. "Development of multidimensional liquid chromatographic methods hyphenated to mass spectrometry : Preparation and analysis of complex biological samples." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/DELMOTTE_Nathanael_2007.pdf.
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Des immunoadsorbeurs ont été développés à partir de disques CIM monolithiques pour l’analyse de biomarqueurs impliqués dans des maladies cardio-vasculaires. Les colonnes développées ont permis d’isoler sélectivement la myoglobine et le NT-proBNP du sérum humain. Les colonnes anti-NT-proBNP ont permis l’isolation quantitative du NT-proBNP (R2 = 0,998) à des concentrations jusqu’à 750 amol/μL de sérum. Six matériaux à accès restreints ont été évalués en fonction de leur aptitude à exclure l’hémoglobine d’hémolysats sanguins. Des injections à différents pH ont montré que la rétention de l’hémoglobine est drastiquement restreinte à pH 10,7. En raison d’une bonne stabilité à pH basique, la colonne polymérique Biotrap 500 MS RAM a été retenue pour l’extraction d’antibiotiques d’hémolysats sanguins. Des extractions quantitatives d’analytes à faibles concentrations (200 pg/μL) ont été réalisées sans effet mémoire d’hémoglobine sur la colonne. Un nouveau système 2D-HPLC-ESI-MS/MS pour l’analyse protéomique a été développé. Le système est composé d’une séparation par RP-HPLC à pH 10,0, suivie d’une séparation par IP-RP-HPLC à pH 2,1. Ce nouveau système a été comparé à un système conventionnel SCX x IP-RP-HPLC. L’orthogonalité des méthodes de séparation est plus élevée dans l’approche SCX x IP-RP-HPLC que dans le schéma RP x IP-RP-HPLC. Cependant, en raison d’une meilleure distribution des peptides et d’une meilleure efficacité de séparation, le système RP x IP-RP-HPLC permet d’identifier significativement plus de peptides. Les deux approches sont complémentaires et une combinaison des deux systèmes permet d’identifier plus de peptides que des analyses répétées par un système unique<br>Immunoadsorbers based on monolithic epoxy-activated CIM disks have been developed in order to target biomarkers of heart diseases. The developed immunoadsorbers permitted to selectively isolate myoglobin and NT-proBNP from human serum. Anti-NT-proBNP-CIM disks permitted a quantitative isolation of NT-proBNP at concentrations down to 750 amol/μL in serum (R2 = 0. 998). Six different restricted access materials have been evaluated with respect to their ability to remove hemoglobin from hemolysates. Experiments at different pH revealed that the retention of hemoglobin can be drastically diminished at pH 10. 7. Because of better chemical stability at high pH, the polymeric Biotrap 500 MS RAM column was optimized for the analysis of hemolysates. The setup permits to quantitatively extract antibiotics from whole blood hemolysates at biologically relevant concentrations (200 pg/μL), and without carry-over of hemoglobin. A new 2D-HPLC-ESI-MS/MS setup for proteome analysis was developed. It consisted of a peptide separation by RP-HPLC at pH 10. 0, followed by IP-RP-HPLC at pH 2. 1. This new setup was compared with a classical SCX x IP-RP-HPLC setup. Separation repeatability is similar with both setups. The orthogonality between methods of separation is higher in the SCX x IP-RP-HPLC approach than in the RP x IP-RP-HPLC scheme. However, the better peptide distribution and separation efficiency achieved with the RP x IP-RP-HPLC setup permitted to identify significantly more peptides than with the classical SCX x IP-RP-HPLC setup. Both approaches are complementary and a combination of both setups permits to identify more peptides than replicate injections performed with a single setup
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Smith, Robert W. "An evaluation of miniaturised field asymmetric waveform ion mobility spectrometry hyphenated with time-of-flight mass spectrometry." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/17837.
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In this thesis, the performance of a miniaturised field asymmetric waveform ion mobility spectrometry (FAIMS) device hyphenated with time-of-flight mass spectrometry is studied and evaluated for analysis of a variety of compounds in different sample matrices. FAIMS is a selective spectrometer which is highly orthogonal to mass spectrometry and has the potential for enhancing sensitivity and improve selectivity of rapid analyses. In Chapter 2, the performance of the miniaturised FAIMS device is tested for stability and transmission under a wide range of ion source conditions. An investigation of three different systems, including pairs of isobaric, isomeric and near-mass ions shows that miniaturised FAIMS has the ability to distinguish between analytes that are challenging to separate by mass spectrometry. Chapter 3 explores the effect of changing the composition of the carrier gas by observing the effect of adding gas modifiers on the FAIMS spectra of small molecules, peptides and proteins. Chapter 4 investigates the advantages of combining a fast FAIMS separation with mass spectrometry in the analysis of nitrogen-containing pharmaceutical impurities, where FAIMS is found to offer additional selectivity. In Chapter 5, the development of a UHPLC-FAIMS-MS method for the quantitative determination of a drug metabolite in urine is reported. UHPLC-FAIMS-MS shows improvements in signal-to noise and linear dynamic range as well as a reduction in chemical noise, demonstrating the potential of combining FAIMS with mass spectrometry.
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Byrne, Elizabeth. "Neither this nor that: the hyphenated existence of Chinese children growing up in twentieth century North America /." Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2313.
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Fedrizzi, Bruno. "Identification, quantitation and origin of sulfur compounds in grape products. An approach via hyphenated mass spectrometry techniques." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426543.
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The contribute of the Analytical Chemistry in the study of complex matrices, as for instance foodstuff, is crucial. In particular the development of chromatographic methods allows to quantify important technological, microbiological and physiological markers. The ensemble of all these information furthers a deeper and higher knowledge.
This Ph.D. project was designed to define the tools and evaluate the contribution of an important class of molecule on wine aroma.
Grape products are really important in the cultural and dietary Italian traditions; moreover Italy is both the first producer and the first consumer around the world. Oenological products have been largely studied since the early ’70, even if the lack of biochemical and microbiological knowledge and the poor sensitivity of the analytical techniques did not allow to carry an deep study on sulfur compounds.
This project, planned to bid analytical and oenological chemistry, focussed its attention on the study of sulfur compounds.
Dealing with complex matrices, the first problem we had to face was the matrix effects. The overcoming of such issue or the attempts in reducing it, costs to chemical laboratory, wasting of time and money to prepare suitable internal standards.
In this thesis we proposed a statistical approach based on the variance component model able to handle matrix effects. The benefits obtained by this approach definitely outweigh both the slightly worse sensitivity and uncertainty.
Another topic discussed in the thesis is the definition of analytical methods to quantify sulfur compounds. This subject has been studied distinguishing sulfur compounds into two sub-groups:
o fermentative sulfur compounds: molecules produced by yeast metabolisms from amino acidic precursors.
o varietal sulfur compounds: molecules present in specific variety, as conjugated with cysteine and glutathione. The free forms, which are sensorially active, are released during fermentation by means of a specific enzymatic activity.
This further classification was kept in the development of the analytical methods because the two classes required different sensitivity as well as metabolomics study were separated.
Concerning fermentative sulfur compounds a HS-SPME/GC-MS method was optimised and validated. With this method a wide range of sulfur compounds were quantified. Such tool was applied to metabolomic studies, concerning the influence of variety, ageing, yeast strain and other technological practice on the level of 13 fermentative sulfur compounds.
The results obtained from the development of the analytical method permitted to highlight the potentiality of the HS-SPME technique in sampling volatile compounds in complex matrices. This approach allows an easier and safer lab conditions, avoiding the use of organic solvents. The metabolomic studies furnished important suggestion on the influence of important oenological variables on the level of important sulfur compounds.
The last topic discussed in this thesis concerns the study of varietal sulfur compounds. The lack of suitable analytical technique, sufficiently rapid and avoiding the use of mercuro-organic compounds stimulated our research in verifying the performance of headspace technique in extracting these analytes.
We optimised and validated HS-SPME and purge and trap methods and finally we defined a non-parametric robust approach to compare performances from different analytical methods.
Owing to the recent interest of the scientific research in trying to understand the formation and evolution of varietal sulfur compounds, we focussed our attention on their precursors.
The first step was the synthesis of the putative precursors, followed by the optimisation of LC-MS/MS methods to quantify them. It was possible to identify a new precursor by LC-MS/MS experiments.
Finally, by the isolation of the enzyme potentially responsible of the biosynthesis of the varietal thiols precursors, we gave a preliminary explanation of the formation of these glutathionylated precursors during grape ripening.
By this project it has been possible to study and apply the newest analytical techniques available and it has been possible to define statistical procedures to overcome the most common issues in studying complex matrices. Furthermore it was clarified the contribution of an important class of molecules, such as sullfur compounds, on oenological matrices.<br>Il contributo della Chimica Analitica nello studio delle matrici complesse, quali ad esempio quelle alimentari, è cruciale. In particolare lo sviluppo di metodi cromatografici avanzati può permettere di dosare importanti marker tecnologici, microbiologici e fisiologici e quindi consentire un approfondimento delle attuali conoscenze.
Questo lavoro è stato concepito allo scopo di definire gli strumenti per valutare il contributo di un’importante classe di molecole all’aroma dei vini.
Il vino riveste un ruolo di primaria importanza nelle tradizioni culturali ed alimentari Italiane, inoltre l’Italia risulta primo produttore e primo consumatore mondiale di vino. I prodotti enologici sono stati largamente studiati fin dai primi anni ’70, anche se l’assenza di conoscenze biochimiche e microbiologiche e la mancanza di tecniche analitiche sufficientemente sensibili non ha consentito lo studio esaustivo della classe dei composti solforati.
Questa tesi, nata da esigenze legate alla chimica analitica e alla chimica enologica, ha avuto come punto centrale lo studio dei composti solforati nei vini.
Il primo problema che si è dovuto affrontare nello studio di matrici complesse come quelle enologiche è stato quello relativo agli effetti matrice. Il superamento o il contenimento di questo problema crea ogni giorno costi in termini di tempo e di preparazione di opportuni standard interni. In questa tesi si è proposto un metodo statistico basato sul modello a componente di varianza in grado di gestire questo problema. I vantaggi sono notevoli, a fronte di una incertezza leggermente maggiore e di una sensibilità di poco peggiorata.
Altro argomento trattato è stata la definizione dei metodi analitici in grado di quantificare e quindi di studiare i composti solforati. Questa materia è stata affrontata riconoscendo una prima distinzione all’interno del gruppo degli analiti indagati:
o composti solforati fermentativi: molecole derivanti dal metabolismo del lievito a partire da precursori amminoacidici
o composti solforati varietali: molecole presenti in specifiche varietà come coniugati della cisteina e del glutatione e rilasciati durante la fermentazione alcolica ad opera di specifiche attività enzimatiche.
Questa suddivisione è stata mantenuta anche nello sviluppo dei metodi analitici, in quanto sensibilità richieste e conseguenze metabolomiche erano anch’esse distinte.
Per quanto riguarda i composti solforati fermentativi, durante il dottorato di ricerca è stato ottimizzato e validato un metodo HS-SPME/GC-MS per l’analisi di un’ampia gamma di molecole tipicamente derivanti dal metabolismo del lievito. Tale approccio è poi stato la base per studi di natura più squisitamente metabolomica in cui è stato verificato come il cultivar (i.e. la varietà), l’invecchiamento, il ceppo di lievito e altre pratiche tecnologiche potessero influenze il livello e l’evoluzione degli analiti indagati.
I risultati ottenuti per quanto attiene lo sviluppo del metodo in spettrometria di massa hanno potuto confermare con la tecnica SPME con campionamento in spazio di testa sia una tecnica di elezione per l’analisi di molecole volatili. Inoltre questo approccio consente una gestione semplice ed enviromental friendly in confronto con i più obsoleti metodi di estrazione con solvente. Gli studi metabolomici hanno consentito di trarre importanti considerazioni su aspetti molto importanti nella definizione della qualità del prodotto finale. Tali risultati consentono anche una trasferibilità nei settori della ricerca applicata e dell’enologia.
Come ultima classe di analiti indagati si sono studiati i composti solforati varietali. L’assenza di metodi sensibili e sufficientemente rapidi da essere applicati per studi su un numero significativo di campioni ha spinto la nostra attenzione alla verifica delle potenzialità delle tecniche in spazio di testa nel dosare queste molecole. Si sono ottimizzati e validati metodi HS-SPME e purge and trap ed è stata definita una procedura non parametrica robusta per il confronto delle performance delle diverse procedure.
Visto il recente interesse della ricerca scientifica operante nel settore al controllo della formazione ed evoluzione di queste molecole, abbiamo focalizzato la nostra attenzione sui precursori dei composti solforati varietali.
Il primo stadio è stata la sintesi di queste molecole, seguito poi dall’ottimizzazione di metodi LC-MS/MS per il dosaggio di queste molecole. In questo contesto è stato possibile identificare per la prima volta un nuovo potenziale precursore di aroma, tramite esperimenti LC-MS/MS.
Da ultimo, attraverso l’isolamento dell’enzima responsabile della biosintesi dei precursori d’aroma è stato possibile proporre una preliminare spiegazione alla formazione di tali molecole durante la maturazione della materia prima.
In conclusione, grazie a questa tesi di dottorato, è stato possibile approfondire ed applicare alcune delle più moderne tecniche analitiche a disposizione, è stato possibile definire procedure statistiche per superare i più comuni ostacoli nello studio di matrici complesse, ed è stato possibile chiarire il contributo di una classe importante di molecole come i composti solforati nelle matrici enologiche.
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Jimoh, Modupeola A. "Development of hyphenated micro analytical methods for trace metal fractionation and their application to environmentally relevant solid matrices." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980207347.
Full text
49
Crotty, Sarah Charlotte [Verfasser], Ulrich Sigmar [Gutachter] Schubert, and Georg [Gutachter] Pohnert. "Characterization of macromolecular systems by mass spectrometry and hyphenated techniques / Sarah Charlotte Crotty ; Gutachter: Ulrich Sigmar Schubert, Georg Pohnert." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1177601435/34.
Full text
50
Silva, Joaquim Carlos Gomes Esteves da. "Acid-base and metal ion complexation properties of humic substances studied by chemometric analysis of spectroscopic-potentiometric hyphenated data." Doctoral thesis, Universidade do Porto. Reitoria, 1994. http://hdl.handle.net/10216/10175.
Full text