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1
Devineau, Camille. "En présence des génies : musique, danse et joie rituelles dans la performance des Masques Blancs chez les Bwaba du Burkina Faso." Thesis, Paris 10, 2019. http://www.theses.fr/2019PA100162.
Full textAbstract:
Le fonctionnement du rituel de la danse des masques blancs chez les Bwaba du Burkina Faso est sous-tendu par l’articulation de trois modes d’expression (musical, dansé et émotionnel) qui mettent en forme son enjeu principal : rendre manifeste une relation entre humains et génies. Bien que rattaché au culte principal des Bwaba, le do, c’est son affiliation au groupe des griots et le lien qui y est développé avec les génies qui priment. En offrant un espace intermédiaire d’interaction entre les dimensions du visible et de l’invisible, ce rituel rend perceptibles certains aspects de la relation qu’entretiennent les griots avec les génies. En mettant conjointement en œuvre les systèmes musicaux et dansés auxquels sont adjoints plusieurs types de manifestations émotionnelles de joie stipulées par le rituel, les participants peuvent faire l’expérience de la présence et de l’implication bienveillante des génies dans le rituel. Tandis que la musique ancre le rituel dans la dimension visible, la danse masquée permet l’intrusion de l’invisible dans la dimension visible des humains. Pour sa part, l’expression émotionnelle de joie garantit l’aspect bienveillant, recherché dans ce rituel, de la relation entre humains et génies. Musique, danse et expressions émotionnelles forment alors un ensemble qui garantit la réussite plus ou moins grande d’une danse de masques blancs par un ressenti concret<br>The interplay of three expressive modes (music, dance and emotional display) underlie the workings of the White Mask dance ritual among the Bwaba people of Burkina Faso, giving shape to its main concern which is to make manifest a relationship between humans and bush spirits. Although tied to the principal Bwaba cult of the do, it is this ritual’s close association with griots and the connection with bush spirits that it puts into effect counts the most. By providing an intermediary space allowing for interactions between visible and invisible realms, this ritual renders certain aspects of the relationship between griots and bush spirits perceptible. By jointly implementing musical and dance forms, as well as a number of stipulated expressions of delight, White Mask performances allow participants to experience bush spirits’ presence and their benevolent involvement. While music anchors the ritual in the visible realm, the masked dance allows the invisible to intrude into the visible, human one. As for expressions of delight, they bear witness to the benevolent nature of the relationship between humans and bush spirits that this ritual seeks to bring about. Music, dance and emotional expression, then, compose a totality whereby the greater or lesser success of a White Mask performance can be appreciated in terms of concrete feelings
2
Kempka, Martin. "Improved mass accuracy in MALDI-TOF-MS analysis." Licentiate thesis, Stockholm : Division of Analytical Chemistry, Royal Institute of Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-313.
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3
Rodrigues, Lívia Riberti 1988. "Análise de impurezas de formas farmacêuticas sólidas por MALDI Mass Spectrometry Imaging (MALDI-MSI)." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312437.
Full textAbstract:
Orientador: Rodrigo Ramos Catharino<br>Texto em português e inglês<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas<br>Made available in DSpace on 2018-08-25T05:33:49Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014<br>Resumo: Atualmente, as doenças cardiovasculares constituem uma das primeiras causas de mortes no Brasil e no mundo. Neste cenário, as estatinas constituem uma notável classe de medicamentos redutores de colesterol e têm sido associadas com uma expressiva diminuição da morbidade e mortalidade cardiovascular para pacientes em prevenção primária ou secundária da doença coronariana. Elas agem inibindo competitivamente a enzima HMG-CoA redutase, através da afinidade destes fármacos pelo sítio ativo da enzima. Esta enzima é responsável por catalisar a conversão do substrato HMG-CoA em mevalonato, um dos precursores do colesterol. A crescente necessidade e busca por medicamentos cada vez mais efetivos traz a preocupação na segurança destes produtos para seus usuários. Neste sentido, o conhecimento das impurezas e produtos de degradação torna-se necessário para garantir sua qualidade. Uma técnica muito utilizada para análises de impurezas e degradantes é a espectrometria de massas, pois é uma técnica sensível e seletiva e permite elucidar as estruturas químicas presentes na formulação do medicamento. Sendo assim, amostras de Atorvastatina cálcica foram analisadas pela técnica de espectrometria de massas por imagem (MALDI-MSI), permitindo a quantificação de impurezas do medicamento através da imagem da distribuição dessa impureza no comprimido. Dessa forma, é possível minimizar o preparo de amostra e obter um melhor conhecimento da formulação<br>Abstract: Currently, cardiovascular diseases constitute one of the first causes of deaths in Brazil and in the world. In this scenario, the statins are a notable class of medicines and cholesterol reducers have been associated with a significant reduction in cardiovascular morbidity and mortality for patients in primary or secondary prevention of coronary heart disease. They act by inhibiting competitively the enzyme HMG-CoA reductase, through the affinity of these drugs by the active site of the enzyme. This enzyme is responsible for catalyzing the conversion of HMG-CoA to mevalonate substrate, one of the precursors of cholesterol. The growing need and search for increasingly effective drugs brings the concern on the safety of these drugs for their users. In this sense, the knowledge of the impurities and degradation products becomes necessary to ensure their quality. A widely used technique for analysis of impurities and degrading is mass spectrometry, because it is a sensitive and selective technique and allows elucidating the chemical structures of the present formulation of the medicinal product. Thus, samples of Atorvastatin calcium were analyzed by the technique of mass spectrometry imaging (MALDI-MSI), which allows the quantification of impurities from the medicine through the image of the distribution of impurity in the tablet. That way, it is possible minimize sample preparation and get a better understanding of the formulation<br>Mestrado<br>Ciencias Biomedicas<br>Mestra em Ciências Médicas
4
Grace, Philip Barry. "The detection and determination of saccharides by mass spectrometric methods." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287374.
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5
uk, siricordcc@yahoo co, and Cornelia Charito Siricord. "Detection of Phytophthora species by MALDI-TOF mass spectrometry." Murdoch University, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20070717.125452.
Full textAbstract:
Phytophthora diseases have caused worldwide economic, social and environmental
impacts for decades. Once their presence is confirmed, they are difficult to eradicate. To
reduce and manage the damage inflicted by the pathogen, fast and reliable disease
management protocols are required. Tests that enable the rapid and reliable
identification of the pathogen assist greatly in disease management.
Phytophthora species are traditionally not only detected by baiting but also by plating of
symptomatic tissue on selective media. Species can be identified by the characteristics
of the mycelium growing out of the bait. However, the method is low throughput,
labour intensive, and prone to false negatives. An alternative approach would be to
detect the pathogen by the presence of its DNA. This involves amplification of the
pathogen DNA using Polymerase Chain Reaction (PCR) and detection of the
amplification product. Detection is usually by agarose gel electrophoresis. However,
this is also a labour intensive process involving pouring, loading, running, and staining
of the gels. The aim of this thesis is to explore the use of Matrix Assisted Laser
Desorption/ Ionisation Time-of-Flight (MALDI-TOF) mass spectrometry for detection
of PCR products. This procedure enables the analysis of large numbers of samples
within a very short time-frame as the average time for analysis of each sample is in the
order of milliseconds.
The assay involves annealing an extension (genotyping) primer to the PCR product and
its extension by a single nucleotide. The nature of the nucleotide added differentiates
species as does the site to which the primer anneals. Multiple extension (genotyping)
primers can be used together in a single reaction for detection of multiple species. In
this project four genotyping primers (GPs) were designed from the ITS regions of
Phytophthora palmivora, Phytophthora cinnamomi, Phytophthora citricola, and
Phytophthora cambivora.
The extension primers were tested for their specificity on the DNA of the target species.
The four primers designed were specific for their intended targets except for GPpalm3
which in addition to being extended by ddT when tested with DNA from P. palmivora,
was also extended by ddC when tested with DNA from other species of Phytophthora
or Pythium.
These primers were also tested for their ability to detect multiple Phytophthora species
in a single reaction (multiplexing). Mixtures of primers were added to mixed DNA
templates and the primer extension reaction carried out. The primers were designed so
that their masses were sufficiently different for them to be identified from a mixture.
Six replicates were analysed for each reaction. In general only about 1-3 of the six
replicates gave a positive reaction. This indicates that there may be some interference
between primers, or that the presence of all four nucleotides interfered with the primer
extension reaction. Increasing either the amount of enzyme, the amount of nucleotides
or both did not improve the results.
The sensitivity of detection was tested by the addition of different amounts of mycelium
to soil. The detection sensitivity depended on the primer pair used for PCR
amplification. The ITS1/2 primer pair was more sensitive than the ITS1/4 pair. The
limit of detection was 1 ìg mycelium g soil-1. However using nested PCR, levels of
sensitivity comparable to those obtained using the ITS1/2 primer pair could be
achieved. Primers to other regions of the genome such as the beta cinnamomin elicitin
gene gave very low levels of sensitivity compared to the ITS primers.
In comparison with DNA detection we found that the limit of detection using baiting
was 4 ìg mycelium g soil-1. Results below this limit were unreliable. The method
suffered from the additional disadvantage that it took a long time in comparison to DNA
detection.
DNA detection methods do not distinguish between living and dead organisms in the
soil. However it can be hypothesised that DNA is unlikely to persist for any significant
length of time in soil. To test this, we added plasmid DNA to soil and tested the
persistence of this DNA using a variety of methods such as precipitation of labelled
DNA, southern blotting and PCR amplification. It was found that in general, in soils
from different ecosystems, the bulk of the DNA was undetectable after 24 hours. The
rate of DNA breakdown differed with the soil type. In some soils, the added DNA was
not detected even after 2 hours, whereas in others it could be observed after 10 hours.
The detection depended on the method. Southern blotting showed that although DNA
could be observed at 10 hours, by 24 hours it was completely degraded. In contrast a
PCR product could be obtained from the soil extracts up to 24 hours. In a separate
experiment, plasmid DNA was detectable over a 24 hour incubation period in 5 soil
samples from 5 different sites. The results suggest that DNA is degraded rapidly in soil
and is unlikely to persist longer than 24 hours.
The results in this thesis demonstrate that MALDI-TOF MS is a suitable alternative to
agarose gel electrophoresis for analysis of PCR products. The technique is rapid,
differentiates species from mixtures, is high-throughput and amenable to automation.
Implementation will require further research to automate the primer extension assay to
reduce the sensitivity to impurities in the DNA and to design parameters for sampling
asymptomatic material.
6
Wyatt, Mark Francis. "Analysis of acrylic polymers by MALDI-TOF mass spectrometry." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3962/.
Full textAbstract:
Poly(methyl methacrylate) (PMMA) homopolymers synthesised using 'classical' anionic methods and subsequently studied by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) are discussed. Specifically, the attempts at different end-group functionalisation reactions, their varying degrees of success, and the characterisation of these functionalized polymers via MALDI are reported. Extra peaks were observed in the spectra of samples containing a tertiary amine end-group. A mechanism for the in situ elimination of H(_2)(g) involving these end-groups, which would fit the observations, is proposed. Two alternative, 'non-classical' routes to the desired materials were investigated, as difficulties in successfully performing capping reactions to give end functionalised PMMA were noted. The first method was a variation of standard anionic polymerisation that involved the use of lithium silanolates, which could be performed at a higher temperature than normal. The second was a controlled free-radical technique known as Reversible Addition-Fragmentation Chain Transfer (RAFT). A lack of control of the polymerisation to the desired degree was observed with the former method. A well-defined RAFT sample was observed to undergo in situ eliminadon also, for which a mechanism involving the dithioester end-group is proposed, and which is supported by MALDI-collision induced dissociation (CID) evidence. The synthesis of block copolymers of various compositions of MMA with r-butyl methacrylate (t-BMA) and hexyl methacrylate (HMA), along with their homopolymers, and their subsequent characterisation is reported. PHMA was analysed easily, in contrast to Pt-BMA. Only copolymers with a high PMMA content were analysed successfully and this has been rationalised in terms of the factors that affect cationisation. The characterisation of equimolar blends of various end-functionalised PMMA samples is reported also. Samples that favour the binding of a metal ion over protonation appear to have a higher ion yield. Once more, these observations are rationalised in terms of the factors that affect cationisation.
7
Siricord, Cornelia Charito. "Detection of Phytophthora species by MALDI-TOF mass spectrometry." Thesis, Siricord, Cornelia Charito (2005) Detection of Phytophthora species by MALDI-TOF mass spectrometry. PhD thesis, Murdoch University, 2005. https://researchrepository.murdoch.edu.au/id/eprint/314/.
Full textAbstract:
Phytophthora diseases have caused worldwide economic, social and environmental impacts for decades. Once their presence is confirmed, they are difficult to eradicate. To reduce and manage the damage inflicted by the pathogen, fast and reliable disease management protocols are required. Tests that enable the rapid and reliable identification of the pathogen assist greatly in disease management.
Phytophthora species are traditionally not only detected by baiting but also by plating of symptomatic tissue on selective media. Species can be identified by the characteristics of the mycelium growing out of the bait. However, the method is low throughput, labour intensive, and prone to false negatives. An alternative approach would be to detect the pathogen by the presence of its DNA. This involves amplification of the pathogen DNA using Polymerase Chain Reaction (PCR) and detection of the amplification product. Detection is usually by agarose gel electrophoresis. However, this is also a labour intensive process involving pouring, loading, running, and staining of the gels. The aim of this thesis is to explore the use of Matrix Assisted Laser Desorption/ Ionisation Time-of-Flight (MALDI-TOF) mass spectrometry for detection of PCR products. This procedure enables the analysis of large numbers of samples within a very short time-frame as the average time for analysis of each sample is in the order of milliseconds.
The assay involves annealing an extension (genotyping) primer to the PCR product and its extension by a single nucleotide. The nature of the nucleotide added differentiates species as does the site to which the primer anneals. Multiple extension (genotyping) primers can be used together in a single reaction for detection of multiple species. In this project four genotyping primers (GPs) were designed from the ITS regions of Phytophthora palmivora, Phytophthora cinnamomi, Phytophthora citricola, and Phytophthora cambivora.
The extension primers were tested for their specificity on the DNA of the target species. The four primers designed were specific for their intended targets except for GPpalm3 which in addition to being extended by ddT when tested with DNA from P. palmivora, was also extended by ddC when tested with DNA from other species of Phytophthora or Pythium.
These primers were also tested for their ability to detect multiple Phytophthora species in a single reaction (multiplexing). Mixtures of primers were added to mixed DNA templates and the primer extension reaction carried out. The primers were designed so that their masses were sufficiently different for them to be identified from a mixture. Six replicates were analysed for each reaction. In general only about 1-3 of the six replicates gave a positive reaction. This indicates that there may be some interference between primers, or that the presence of all four nucleotides interfered with the primer extension reaction. Increasing either the amount of enzyme, the amount of nucleotides or both did not improve the results.
The sensitivity of detection was tested by the addition of different amounts of mycelium to soil. The detection sensitivity depended on the primer pair used for PCR amplification. The ITS1/2 primer pair was more sensitive than the ITS1/4 pair. The limit of detection was 1 mcg mycelium g soil-1. However using nested PCR, levels of sensitivity comparable to those obtained using the ITS1/2 primer pair could be achieved. Primers to other regions of the genome such as the beta cinnamomin elicitin gene gave very low levels of sensitivity compared to the ITS primers.
In comparison with DNA detection we found that the limit of detection using baiting was 4 mcg mycelium g soil-1. Results below this limit were unreliable. The method suffered from the additional disadvantage that it took a long time in comparison to DNA detection.
DNA detection methods do not distinguish between living and dead organisms in the soil. However it can be hypothesised that DNA is unlikely to persist for any significant length of time in soil. To test this, we added plasmid DNA to soil and tested the persistence of this DNA using a variety of methods such as precipitation of labelled DNA, southern blotting and PCR amplification. It was found that in general, in soils from different ecosystems, the bulk of the DNA was undetectable after 24 hours. The rate of DNA breakdown differed with the soil type. In some soils, the added DNA was not detected even after 2 hours, whereas in others it could be observed after 10 hours. The detection depended on the method. Southern blotting showed that although DNA could be observed at 10 hours, by 24 hours it was completely degraded. In contrast a PCR product could be obtained from the soil extracts up to 24 hours. In a separate experiment, plasmid DNA was detectable over a 24 hour incubation period in 5 soil samples from 5 different sites. The results suggest that DNA is degraded rapidly in soil and is unlikely to persist longer than 24 hours.
The results in this thesis demonstrate that MALDI-TOF MS is a suitable alternative to agarose gel electrophoresis for analysis of PCR products. The technique is rapid, differentiates species from mixtures, is high-throughput and amenable to automation. Implementation will require further research to automate the primer extension assay to reduce the sensitivity to impurities in the DNA and to design parameters for sampling asymptomatic material.
8
Siricord, Cornelia Charito. "Detection of Phytophthora species by MALDI-TOF mass spectrometry." Siricord, Cornelia Charito (2005) Detection of Phytophthora species by MALDI-TOF mass spectrometry. PhD thesis, Murdoch University, 2005. http://researchrepository.murdoch.edu.au/314/.
Full textAbstract:
Phytophthora diseases have caused worldwide economic, social and environmental impacts for decades. Once their presence is confirmed, they are difficult to eradicate. To reduce and manage the damage inflicted by the pathogen, fast and reliable disease management protocols are required. Tests that enable the rapid and reliable identification of the pathogen assist greatly in disease management.
Phytophthora species are traditionally not only detected by baiting but also by plating of symptomatic tissue on selective media. Species can be identified by the characteristics of the mycelium growing out of the bait. However, the method is low throughput, labour intensive, and prone to false negatives. An alternative approach would be to detect the pathogen by the presence of its DNA. This involves amplification of the pathogen DNA using Polymerase Chain Reaction (PCR) and detection of the amplification product. Detection is usually by agarose gel electrophoresis. However, this is also a labour intensive process involving pouring, loading, running, and staining of the gels. The aim of this thesis is to explore the use of Matrix Assisted Laser Desorption/ Ionisation Time-of-Flight (MALDI-TOF) mass spectrometry for detection of PCR products. This procedure enables the analysis of large numbers of samples within a very short time-frame as the average time for analysis of each sample is in the order of milliseconds.
The assay involves annealing an extension (genotyping) primer to the PCR product and its extension by a single nucleotide. The nature of the nucleotide added differentiates species as does the site to which the primer anneals. Multiple extension (genotyping) primers can be used together in a single reaction for detection of multiple species. In this project four genotyping primers (GPs) were designed from the ITS regions of Phytophthora palmivora, Phytophthora cinnamomi, Phytophthora citricola, and Phytophthora cambivora.
The extension primers were tested for their specificity on the DNA of the target species. The four primers designed were specific for their intended targets except for GPpalm3 which in addition to being extended by ddT when tested with DNA from P. palmivora, was also extended by ddC when tested with DNA from other species of Phytophthora or Pythium.
These primers were also tested for their ability to detect multiple Phytophthora species in a single reaction (multiplexing). Mixtures of primers were added to mixed DNA templates and the primer extension reaction carried out. The primers were designed so that their masses were sufficiently different for them to be identified from a mixture. Six replicates were analysed for each reaction. In general only about 1-3 of the six replicates gave a positive reaction. This indicates that there may be some interference between primers, or that the presence of all four nucleotides interfered with the primer extension reaction. Increasing either the amount of enzyme, the amount of nucleotides or both did not improve the results.
The sensitivity of detection was tested by the addition of different amounts of mycelium to soil. The detection sensitivity depended on the primer pair used for PCR amplification. The ITS1/2 primer pair was more sensitive than the ITS1/4 pair. The limit of detection was 1 mcg mycelium g soil-1. However using nested PCR, levels of sensitivity comparable to those obtained using the ITS1/2 primer pair could be achieved. Primers to other regions of the genome such as the beta cinnamomin elicitin gene gave very low levels of sensitivity compared to the ITS primers.
In comparison with DNA detection we found that the limit of detection using baiting was 4 mcg mycelium g soil-1. Results below this limit were unreliable. The method suffered from the additional disadvantage that it took a long time in comparison to DNA detection.
DNA detection methods do not distinguish between living and dead organisms in the soil. However it can be hypothesised that DNA is unlikely to persist for any significant length of time in soil. To test this, we added plasmid DNA to soil and tested the persistence of this DNA using a variety of methods such as precipitation of labelled DNA, southern blotting and PCR amplification. It was found that in general, in soils from different ecosystems, the bulk of the DNA was undetectable after 24 hours. The rate of DNA breakdown differed with the soil type. In some soils, the added DNA was not detected even after 2 hours, whereas in others it could be observed after 10 hours. The detection depended on the method. Southern blotting showed that although DNA could be observed at 10 hours, by 24 hours it was completely degraded. In contrast a PCR product could be obtained from the soil extracts up to 24 hours. In a separate experiment, plasmid DNA was detectable over a 24 hour incubation period in 5 soil samples from 5 different sites. The results suggest that DNA is degraded rapidly in soil and is unlikely to persist longer than 24 hours.
The results in this thesis demonstrate that MALDI-TOF MS is a suitable alternative to agarose gel electrophoresis for analysis of PCR products. The technique is rapid, differentiates species from mixtures, is high-throughput and amenable to automation. Implementation will require further research to automate the primer extension assay to reduce the sensitivity to impurities in the DNA and to design parameters for sampling asymptomatic material.
9
Borsani, M. "BIOINFORMATICS APPROACHES TO MALDI-TOF MASS SPECTROMETRY DATA ANALYSIS." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/221050.
Full textAbstract:
Despite the increasing performance of Mass spectrometry (MS) and others analytical tools, only few biomarkers have been validated and proved to be robust and clinically relevant; indeed a large numbers of proteomic biomarkers have been described, but they are not yet clinical implemented [1]. MALDI-TOF MS seems one of the more powerful tool for biomarkers discovery [2, 3], and shows interesting clinical properties, for instance the possibility to directly search in peripheral fuids for proteins related to an altered physiological state: samples (urine, plasma, serum, etc.) can be collected easily and cheaply by non-invasive, or very low-invasive, methods [4]. The combination of some biomarkers is actually considered more informative than a single biomarker [5, 6], and the improvement in the bioinformatics analysis of MS data could probably help this investigation, decreasing costs and time necessary for each discovery [7].
It is possible to approach the problems related to the analysis of (MALDI-TOF) MS data in two ways, either trying to increase the number of available samples or by reducing the complexity of the problem [8]: in the first case, we developed an approach to compare small datasets from different sources (i.e. hospitals), based on mutual information and mass spectra alignment, that showed significant performance increase compare to the competing ones tested.
In the latter case, we developed novel methods and approaches to compare MALDI-TOF MS profiles of normal and Renal Cell Carcinoma (RCC) patients, with the goal of isolating the more interesting subset of small proteins and peptides from the whole analysed peptidome. MS-based profiling is in fact able to detect differently expressed proteins or peptides during physiological and pathological processes. Every MALDI-TOF MS spectrum, that reports the relative abundance of sample analytes, could be considered as a snapshot of samples peptidome in a definite mass range. The relationship between mass/charge ratio, or m/z, and concentration of detected peptides can be represented by networks. Tumor case and control subjects show different peptidome profiles, due to differences in biomolecular and/or biochemical features of cancer cells: they will show some changes in the networks that describe them. We use graphs to create networks representation of data and to evaluate networks properties. We explore the networks properties comparing cases versus controls datasets, and subdividing cases in the different histological subtypes of RCC, clear cell RCC (ccRCC) and not-ccRCC, using different methods both for networks creation and analysis, and for results evaluation. We identify, for each datasets (controls, ccRCC and not-ccRCC) some interesting mass ranges within which we believe biomarkers signals should be searched.
In conclusion, we have developed a set of methods which we believe improve the current computational approaches for the analysis of mass spectrometry data. These results have been published or presented at workshops and conferences.
10
DONG, YONGHUI. "Mass spectrometry imaging: looking fruits at molecular level." Doctoral thesis, country:IT, 2014. http://hdl.handle.net/10449/24270.
Full textAbstract:
Mass spectrometry imaging (MSI) is a MS-based technique. It provides a way of ascertaining both spatial distribution and relative abundance of a large variety of analytes from various biological sample surfaces. MSI is able to generate distribution maps of multiple analytes simultaneously without any labeling and does not require a prior knowledge of the target analytes, thus it has become an attractive molecular histology tool. MSI has been widely used in medicine and pharmaceutical fields, while its application in plants is recent although information regarding the spatial organization of metabolic processes in plants is of great value for understanding biological questions such as plant development, plant environment interactions, gene function and regulatory processes.
The application of MSI to these studies, however, is not straightforward due to the inherent complexity of the technique. In this thesis, the issues of plant sample preparation, surface properties heterogeneity, fast MSI analysis for spatially resolved population studies and data analysis are addressed. More specifically, two MSI approaches, namely matrix assisted laser desorption ionization (MALDI) imaging and desorption electrospray ionization (DESI) imaging, have been evaluated and compared by mapping the localization of a range of secondary and primary metabolites in apple and grapes, respectively. The work based on MALDI has been focused on the optimization of sample preparation for apple tissues to preserve the true quantitative localization of metabolites and on the development of specific data analysis tool to enhance the chemical identification in untargeted MSI (chapter 3). MALDI imaging allows high-spatial localization analysis of metabolites, but it is not suitable for applications where rapid and high throughput analysis is required when the absolute quantitative information is not necessary as in the case of screening a large number of lines in genomic or plant breeding programs. DESI imaging, in contrast, is suitable for high throughput applications with the potential of obtaining statistically robust results. However, DESI is still in its infancy and there are several fundamental aspects which have to be investigated before using it as a reliable technique in extensive imaging applications. With this in mind, we investigated how DESI imaging can be used to map the distribution of the major organic acids in different grapevine tissue parts, aiming at statistically comparing their distribution differences among various grapevine tissues and gaining insights into their metabolic pathways in grapevine. Our study demonstrated that this class of molecules can be successfully detected in grapevine stem sections, but the surface property differences within the structurally heterogeneous grapevine tissues can strongly affect their semi-quantitative detection in DESI, thereby masking their true distribution. Then we decided to investigate this phenomenon in details, in a series of dedicated imaging studies, and the results have been presented in chapter 4. At the same time, during DESI experiments we have observed the production of the dianions of small dicarboxylates acids. We further studied the mechanism of formation of such species in the ion source proposing the use of doubly charged anions as a possible proxy to visualize the distributions of organic acid salts directly in plant tissues (chapter 5). The structural organization of the PhD thesis is as below:
Chapter one and Chapter two describe the general MSI principle, compare the most widely used MSI ion sources, and discuss the current status in MSI data pre-processing and statistical methods. Due to the importance of sample preparation in MSI, sample handling for plant samples is independently reviewed in chapter two, with all the essential steps being fully discussed. The first two chapters describe the comprehensive picture regarding to MSI in plants.
Chapter three presents high spatial and high mass resolution MALDI imaging of flavonols and dihydrochalcones in apple. Besides its importance in plant research, our results demonstrate that how data analysis as such Intensity Correlation Analysis could benefit untargeted MSI analysis.
Chapter four discusses how sample surface property differences in a structurally/biologically heterogeneous sample affect the quantitative mapping of analytes in the DESI imaging of organic acids in grapevine tissue sections.
Chapter five discusses the mechanism of formation of dicarboxylate dianions in DESI and ESI
Chapter six summarizes the work in the thesis and discusses the future perspectives.
11
Kirmess, Kristopher Michael. "Investigation of Primary Ion Formation Mechanisms in UV-MALDI-MS Using Excited State Dynamics of Common MALDI Matrices." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1110.
Full textAbstract:
The motivation of this dissertation is to provide insight towards primary ionization mechanisms within MALDI mass spectrometry. Albeit MALDI-MS is an extensively used analytical technique, the mechanism in which primary ions are created is still under scrutiny. Two current models of primary ionization exist which claim to elucidate the ion formation mechanisms within MALDI. In this work, excited state dynamics of MALDI matrices are shown to play an important role in the ionization mechanism. Upon inspection of the thermodynamic properties of commonly used MALDI matrices, no correlation was observed when plotted against their respective analyte ion yields. However, the excited state singlet lifetimes of these matrices seem to correlate well with their respective analyte ion yields. In the broadest sense, this correlation further supports the fact that photophysical properties of the matrix should be included in current UV-MALDI models. Investigation of a claim which stated singlet energy pooling reactions were absent in the MALDI matrix 2,4,6-trihydroxyacetophenone (THAP) resulted in the discovery of a new energy pooling mechanisms. Characteristic of aromatic ketones such as THAP, intersystem crossing is an efficient process in solution, which gives way to fluorescence in the solid state. Triplet pooling mechanisms from two neighboring THAP molecules are proposed and appear to be dependent on the preparation solvent used. These triplet pooling reactions are thought to play an important role in the primary ion formation mechanism within MALDI. To further investigate the theory of triplet species playing a vital role in MALDI ionization, the internal heavy-atom effect was employed to determine the effect of the triplet species. MALDI mass spectra and excited state decays of these heavy-atom substituted matrices were collected to demonstrate the relationship between triplet species and analyte ionization efficiency. Gas-phase thermodynamics and absorption at 337 nm were also examined to determine if these properties affected the analyte ion signal observed in the MALDI mass spectrum. Using the information collected from the previous study, an advanced MALDI matrix is synthesized. Addition of covalently bound iodine to the gold standard matrix, α-cyano-hydroxycinnamic acid, should drastically improve the performance of the non-substituted matrix due to the increase in triplet species present for pooling reactions. Sample preparation methods in MALDI are examined as are the effects of crystal morphology on the overall signal observed in the mass spectrum. Exciton hopping and pooling rates are highly dependent on intermolecular interactions, so it is expected that crystal packing will affect MALDI. As noted for THAP, preparation solvent plays a significant role in not only crystal morphology, but also the excited state dynamics for all matrices studied.
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Macnamara, Jim R., University of Western Sydney, of Arts Education and Social Sciences College, and School of Education and Early Childhood Studies. "Representations of men and male identities in Australian mass media." THESIS_CAESS_EEC_Macnamara_J.xml, 2004. http://handle.uws.edu.au:8081/1959.7/735.
Full textAbstract:
Gender has been identified as a key element of human identity. Feminism has focussed particular attention on gender issues over the past five decades. Gender discourse has been dominated by discussion of women and women’s issues - “feminists have somehow set the agenda for men’s studies” as well as women studies. Mass media have been identified as key sites of discourse in feminist studies. Numerous studies have examined representations of women in mass media and argued that these have significant effects on women, on men, and on societies. A number of researchers have found that the treatment of men in mass media is not unproblematic and say that that feminist-led discourses have presented pictures of men as rapists, batterers, pornographers, child abusers, militarists, exploiters, and images of women as targets and victims. But studies of representations of men have been far fewer than those focussing on women. Furthermore, some media content analyses have been limited or unreliable because of small samples or lack of methodological rigor<br>Doctor of Philosophy (PhD)
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Allwood, Daniel Anthony. "Characterisation and ionisation modelling of matrices in MALDI mass spectrometry." Thesis, University of Hull, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301477.
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Guan, Bing. "Characterization of Oligosaccharides and Nanoparticles by MALDI-TOF Mass Spectrometry." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/585.
Full textAbstract:
The possibilities of differentiating linkage positions and anomeric configurations of small oligosaccharides by negative ion mode MALDI using anion attachment followed by PSD are investigated. By careful initial adjustment of the focusing mirror ratios allowing acquisition of the peaks of interest within the same PSD segment, it is possible to obtain highly reproducible relative ion abundances. Discrimination of different linkage types is achieved by analysis of structurally-informative diagnostic peaks offered by PSD spectra of chloride adducts of oligosaccharides, whereas the relative peak intensities of selected diagnostic fragment pairs make differentiation of anomeric configuration possible. F- and Ac- cannot form anionic adducts with the oligosaccharides in significant yields. However, Br-, I- and NO3- anionic adducts consistently appear in higher abundances relative to [M - H]-, just like Cl-. Mildly acidic saccharides form both deprotonated molecules and anionic adducts, making it possible to simultaneously detect neutral and acidic oligosaccharides via anion attachment. PSD of [oligosaccharide + Cl]- yields structurally-informative fragment ions that retain the charge on the sugar molecule rather than solely forming Cl-, whereas PSD of Br-, I- and NO3- adducts of oligosaccharides yield the respective anions as the main product ions without offering structural information concerning the sugar. PSD of the chloride adduct of saccharides containing 1-2 linkages also yields chlorine-containing fragment ions. MALDI-TOF-MS and LDI-TOF-MS are shown to be useful for characterization of ultra-small titania nanoparticles. Peak maxima in MALDI-TOF mass spectra are found to correlate with nanoparticle size. The size distributions of TiO2 nanoparticles, obtained from MALDI- and LDI-TOF-MS are in good agreement with parallel TEM observations. PSD analysis of inorganic x nanomaterials is performed and valuable information about the structure of analytes has been obtained. A group of inorganic nitrate and perchlorate salts of forensic and health interest are investigated by LDI- and MALDI-TOF MS. In each case, a series of characteristic cluster ions are predominant in the negative-ion mode. The number and identity of metal atoms and anions in the recorded cluster ions can be positively identified by their m/z values, distinctive isotopic patterns and characteristic PSD fragmentation patterns.
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Garrison, Megan C. "Size Matters: Television Media Effects on Male Body Image." Xavier University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=xavier1395151552.
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Segu, Mohideen Mohamed Zaneer. "TARGET MODIFICATION FOR ENHANCED PERFORMANCE MATRIX ASSISTED LASER DESORPTION IONIZATION (MALDI) MASS SPECTROMETRY." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1674093101&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (Ph. D.)--Southern Illinois University Carbondale, 2008.<br>"Department of Chemistry." Keywords: Enhanced MALDI, MALDI-MS, On-probe separation, Protein-surface interactions, Sublayers, Surface binding capacity. Includes bibliographical references (p. 130-148). Also available online.
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Watson, R. Craig Jr. "Laser-Ionization Time-of-Flight Mass Spectrometry of High Molecular Mass Inorganic Complexes." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35554.
Full textAbstract:
Laser-Ionization Time-of-Flight Mass Spectrometry (LI-TOF-MS) is a sophisticated tool for the molecular-weight determination and structural characterization of a variety of molecules. Advances in instrumentation and ionization methods have recently expanded its role in the analysis of high-mass analytes. Large multimetallic complexes, which are efficient solar-energy converters, rely heavily on their chemical structure for optimum operation. Molecular mass determinations of these multimetallic complexes have been problematic due to their lability and high molecular weights.
<p>
This thesis describes the characterization of a LI-TOF-MS instrument and confirmation of theoretical time-of-flight mass-separation principles. Several test cases demonstrate the instrument's proper operation and calibration for a wide mass range of analytes. Mass spectral results of three organometallic compounds: i. [Ir(dpp)<sub>2</sub>Cl<sub>2</sub>](PF<sub>6</sub>), ii. {[(bpy)<sub>2</sub>Ru(dpp)]<sub>2</sub>IrCl<sub>2</sub>}(PF<sub>6</sub>)<sub>5</sub>, and iii. {[(bpy)<sub>2</sub>Ru(dpp)]<sub>2</sub>RuCl<sub>2</sub>}(PF<sub>6</sub>)<sub>5</sub> under a variety of laser ionization and sample preparation conditions are compared. A complete structural characterization of the monometallic complex, [Ir(dpp)<sub>2</sub>Cl<sub>2</sub>](PF<sub>6</sub>), is presented. The two trimetallic analytes fragmented easily, but significant components of the molecules are successfully identified. After optimizing the ionization and analytical procedure, LI-TOF-MS proved useful in the analysis of high molecular mass metal complexes.<br>Master of Science
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Oduwole, Elizabeth O. "Generation of a database of mass spectra patterns of selected Mycobacterium species using MALDI-ToF mass spectrometry." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/2838.
Full textAbstract:
Thesis (MScMedSc (Pathology. Medical Microbiology))--Stellenbosch University, 2008.<br>The genus Mycobacterium is a group of acid–fast, aerobic, slow- growing organisms which include
more than 90 different species. A member of this genus, Mycobacterium tuberculosis, belonging to
the Mycobacterium tuberculosis complex (MTB), is the causative agent of tuberculosis (TB). This
disease is currently considered a global emergency, with more than 2 million deaths and over 8
million new cases annually. TB is the world’s second most common cause of death after
HIV/AIDS. About one-third of the world’s population is estimated to be infected with TB. This
catastrophic situation is further compounded by the emergence of Multi Drug Resistant tuberculosis
(MDR-TB) and in more recent times, Extensive Drug Resistant tuberculosis (XDR-TB). Early
diagnosis is critical to the successful management of patients as it allows informed use of
chemotherapy. Also, early diagnosis is also of great importance if the menace of MDR-TB and
XDR-TB is to be curbed and controlled.
As MTB is highly infectious for humans, it is of paramount importance that TB be diagnosed as
early as possible to stop the spread of the disease. Traditional conventional laboratory procedures
involving microscopy, culture and sensitivity tests may require turnaround times of 3-4 weeks or
longer. Tremendous technological advancement over the years such as the advent of automated
liquid culture systems like the BACTEC® 960 and the MGITTM Tube system, and the development
of a myriad of molecular techniques most of which involves nucleic acid amplification (NAA) for
the rapid identification of mycobacterial isolates from cultures or even directly from clinical
specimens have contributed immensely to the early diagnosis of tuberculosis. Most of these NAA
tests are nevertheless fraught with various limitations, thus the search for a rapid, sensitive and
specific way of diagnosing tuberculosis is still an active area of research. The search has expanded to areas that would otherwise not have been considered ‘conventional’ in diagnostic
mycobacteriology. One of such areas is mass spectrometry.
This study joins the relatively few studies of its kind encountered in available literature to establish
the ground work for the application of mass spectrometry, specifically Matrix Assisted Laser
Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF MS) in the field of
diagnostic mycobacteriology. This is an area which is in need of the speed, sensitivity and
specificity that MALDI-ToF technique promises to offer. Since this technology is still in its
infancy, the use of utmost care in the preparation of reagents, and the handling and storage of the
organisms used to generate reference mass spectra for the database cannot be overemphasized.
Similarly, the optimization of certain crucial experimental factors such as inactivating method and
choice of matrix is of paramount importance.
The main aim of this thesis was to generate a database of reference mass spectra fingerprints of
selected (repository) Mycobacterium species. This necessitated the standardization of an
experimental protocol which ensured that experimental factors and the various instrument
parameters were optimized for maximum spectra generation and reproducibility. A standard
operating procedure (SOP) for generating the database of reference mass spectra finger print of
selected Mycobacterium species was developed and used to investigate the ability of the database to
differentiate between species belonging to the same clinical disease complex as well as the nontuberculosis
complex.
The findings of this study imply that if the defined protocol is followed, the database generated has
the potential to routinely identify and differentiate (under experimental conditions) more species of Mycobacterium than is currently practical using PCR and its related techniques. It is therefore a
realistic expectation that when the database is clinically validated and tested in the next phase of the
study, it will contribute immensely to the diagnosis of tuberculosis and other mycobacterioses. It
will also aid in the identification of emerging pathogens particularly amongst the non-tuberculous
mycobacteria.
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Zabet, Moghaddam Masoud. "MALDI mass spectrometry and ionic liquids applications in functional protein analysis /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982074360.
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DENTI, VANNA. "Development of multi-omic mass spectrometry imaging approaches to assist clinical investigations." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/365169.
Full textAbstract:
Con il termine di –omica spaziale si intende l’insieme di diverse tecniche che consentono di rilevare alterazioni significative delle biomolecole all’interno dei loro tessuti d’origine o delle strutture cellulari, permettendo quindi di integrare ed ampliare la comprensione dei cambiamenti biologici che si verificano in tessuti patologici complessi ed eterogenei, come il cancro. Tuttavia, per comprendere appieno la complessità e le dinamiche al di là delle condizioni patologiche, è necessario studiare e integrare diverse analisi molecolari, come quelle di lipidi e glicani, in modo da ottenere un’istantanea molecolare il più completa ed estesa possibile della malattia. Tra le tecniche di -omica spaziale, quella di desorbimento e ionizzazione laser assistiti da matrice (MALDI) abbinata alla spettrometria di massa imaging (MSI), permette lo studio della componente molecolare del tessuto patologico tramite un approccio multiplex, che permette di esaminare diverse centinaia di biomolecole in una singola analisi. Pertanto, l’analisi MALDI-MSI viene utilizzata per studi -omici spaziali di proteine, peptidi e N-glicani su campioni di tessuti clinici fissati in formalina e inclusi in paraffina (FFPE). Per quanto riguarda i lipidi, invece, questo tipo di analisi è sempre stato considerato poco efficace su campioni FFPE a causa della perdita di una grande quantità di contenuto lipidico durante le fasi di lavaggio con solventi organici, mentre i restanti lipidi resistenti ai solventi sono inaccessibili poiché trattenuti nei legami incrociati della formalina.
In questi tre anni di dottorato, abbiamo sviluppato nuovi approcci MALDI-MSI per l'analisi spaziale multi-omica su campioni di tessuto clinico FFPE.
Le prime tre pubblicazioni riportate in questa tesi si sono concentrate sullo sviluppo di protocolli MALDI-MSI per lipidi in campioni FFPE. In particolare, due di essi descrivono il metodo di preparazione del campione per la rilevazione di ioni di fosfolipidi carichi positivamente, principalmente fosfatidilcoline (PC), in campioni clinici di carcinoma renale a cellule chiare (ccRCC) e in un modello di xenotrapianto di cancro al seno. La terza pubblicazione riporta la possibilità di utilizzare ioni di fosfolipidi carichi negativamente, principalmente fosfatidilinositoli (PI), per definire firme lipidiche in grado di distinguere i gradi di tumore del colon-retto che presentano diverse quantità di linfociti infiltranti il tumore (TIL).
Il lavoro finale propone un originale metodo MALDI-MSI multi-omico per l'analisi sequenziale di lipidi, N-glicani e peptidi triptici su una singola sezione FFPE. In particolare, il metodo è stato inizialmente implementato su replicati tecnici di cervello murino e successivamente utilizzato su campioni di ccRCC, come ulteriore prova, ottenendo una caratterizzazione più completa del tessuto tumorale grazie alla combinazione delle informazioni molecolari.
Complessivamente, questi risultati aprono la strada a un nuovo approccio multi-omico spaziale basato sulla spettrometria di massa imaging (MSI) che è in grado di restituire un ritratto molecolare più ampio e più preciso della malattia.<br>The field of spatial omics defines the gathering of different techniques that allow the detection of significant alterations of biomolecules in the context of their native tissue or cellular structures. As such, they extend the landscape of biological changes occurring in complex and heterogeneous pathological tissues, such as cancer. However, additional molecular levels, such as lipids and glycans, must be studied to define a more comprehensive molecular snapshot of disease and fully understand the complexity and dynamics beyond pathological condition. Among the spatial-omics techniques, matrix-assisted laser desorption/ionisation (MALDI)-mass spectrometry imaging (MSI) offers a powerful insight into the chemical biology of pathological tissues in a multiplexed approach where several hundreds of biomolecules can be examined within a single experiment. Thus, MALDI-MSI has been readily employed for spatial omics studies of proteins, peptides and N-Glycans on clinical formalin-fixed paraffin-embedded (FFPE) tissue samples. Conversely, MALDI-MSI analysis of lipids has always been considered not feasible on FFPE samples due to the loss of a great amount of lipid content during washing steps with organic solvents, with the remaining solvent-resistant lipids being involved in the formalin cross-links.
In this three-year thesis work, novel MALDI-MSI approaches for spatial multi-omics analysis on clinical FFPE tissue samples were developed.
The first three publications reported in this thesis focused on the development of protocols for MALDI-MSI of lipids in FFPE samples. In particular, two of them describe a sample preparation method for the detection of positively charged phospholipids ions, mainly phosphatidylcholines (PCs), in clinical clear cell Renal Cell Carcinoma (ccRCC) samples and in a xenograft model of breast cancer. The third publication reports the possibility to use negatively charged phospholipids ions, mainly phosphatidylinositols (PIs), to define lipid signatures able to distinguish colorectal cancers with different amount of tumour infiltrating lymphocytes (TILs).
The final work proposes a unique multi-omic MALDI-MSI method for the sequential analysis of lipids, N-Glycans and tryptic peptides on a single FFPE section. Specifically, the method feasibility was first established on murine brain technical replicates. The method was consequently used on ccRCC samples, as a proof of concept, assessing a more comprehensive characterisation of the tumour tissue when combining the multi-level molecular information.
Altogether, these findings pave the way for new MSI-based spatial multi-omics approach aiming at an extensive and more precise molecular portrait of disease.
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Townsend, Shawnda Kristina. "Contemporary rape reportage in The Courier-Mail." Thesis, Queensland University of Technology, 1994. https://eprints.qut.edu.au/36396/1/36396_Townsend_1994.pdf.
Full textAbstract:
This study examined contemporary rape reportage in The
Courier-Mail. Much of our understanding of the social world derives from the information in media news sources. This is especially true of areas such as crime, including rape, with which many people will have no personal contact. Given that our perceptions of this crime will be largely formed from media messages, it is critical that we fully understand just how the media does present rape and what effects this presentation may have.
This study applied a careful, detailed content ·analysis
to a 1992 case study of The Courier-Mail news reports and
editorials dealing with rape. It specifically addressed two hypotheses: The Courier-Mail distorts the social problem of rape by 1) perpetuating common rape myths and by 2) disguising the social origins of rape.
The analysis revealed that common rape myths do receive
reinforcement in a significant proportion of the news items. It also found that The Courier-Mail does disguise the social causes of rape sexual inequality within a patriarchal society - by presenting rape as the isolated act of one deviant individual rather than as a systematic expression of male dominance and aggression. This distortion in news reportage prevents readers from developing a complex understanding of the crime and from developing effective strategies for combating the crime by attacking the deeper social causes of rape.
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SMITH, ANDREW JAMES. "MALDI-MSI in the study of glomerulonephritis: Possible molecular indicators of CKD progression." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/153198.
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Le glomerulonefriti idiopatiche (GN), tra cui le nefropatie membranose (MN), le glomerulosclerosi segmentarie e focali (FSGS) e la nefropatia da IgA (IgAN), rappresentano le più frequenti patologie glomerulari primarie e sono spesso causa insufficienza renale terminale (ESRD).
Senza una corretta diagnosi e la consegnuente scelta di un opportuno trattamento, la patologia presenta elevate probabilità di progredire verso uno stadio terminale, obbligando il paziente a sottoporsi a cicli di dialisi o al trapianto di rene. Ad oggi, la biopsia renale rimane la tecnica di elezione per la diagnosi delle GN idiopatiche, ma, considerando i problemi legati all’invasività di questa tecnica e la sua non perfetta capacità di garantire sempre una corretta diagnosi, biomarcatori diagnostici e prognostici, utilizzabili con tecniche meno invasive, stanno sempre di più diventando indispensabili.
La spettrometria di massa MALDI-MS Imaging è una tecnologia avanzata che permette un’integrazione tra le informazioni molecolari ottenute da studi di proteomica tissutale e le caratteristiche morfologiche. La possibilità di correlare la distribuzione spaziale di una vasta gamma di analiti direttamente in situ con le informazioni istologiche rende questa tecnica uno strumento ottimale per la ricerca di nuovi biomarcatori, non solo a livello di alterazioni molecolari ma anche di variazioni nella posizione nel tessuto. Inoltre, per quanto riguarda il campo della nefrologia, il MALDI-MS Imaging permette potenzialmente di ottenere la firma proteomica dei glomeruli e dei tubuli, sia dei pazienti affetti da patologia che dei pazienti controllo.
Questa tesi si focalizza sull’utilizzo del MALDI-MS Imaging per l’analisi di biopsie renali, sia di tessuti freschi/congelati che tessuti fissati in formalina ed inclusi in paraffina (FFPE), con lo scopo di identificare marker diagnostici e prognostici associabili alle più comuni forme di glomerulonefriti. In particolare, il MALDI-MS Imaging è stato applicato a campioni freschi di biopsia renale di pazienti affetti da FSGS (n = 6) e di controlli, così da ottenere la firma molecolare delle glomerulonefriti primarie. Questa tecnica ha permesso di ottenere un profilo molecolare in grado di discriminare tra tessuto renale sano e patologico, grazie a segnali specifici (m/z 4025 and 4048) caratteristici della patologia. Tra questi segnali, lo ione a m/z 4048 è stato anche identificato come α-1-antitrypsin (A1AT), localizzato in maniera specifica nei podociti dei glomeruli sclerotici. Questa proteina potrebbe essere reposnsabile dello stress dei podociti e essere quindi strettamente correlata con lo sviluppo di FSGS.
Infine, utilizzando un protocollo precedentemente sviluppato e ottimizzato, biopsie renali FFPE di pazienti con glomerulopatie primarie e secondarie (n = 20) sono state analizzate con lo scopo di identificare alterazioni nel proteoma tissutale tipiche della singola patologia. In particolare il segnale a m/z 1459, identificato come Serine/threonine-protein kinase MRCK gamma, è risultato essere maggiormente intenso nei glomeruli di pazienti con MN primaria rispetto a quelli con MN secondaria. Questo approccio proteomico ha quindi permesso di ottenere una firma molecolare delle MN primarie e secondario oltre che una serie di segnali in grado di differenziare le diverse forme di MN idiopatiche. Tutti questi segnali potrebbero rappresentare target da studiare come potenziali marker proteomici in grado di stratificare ulteriormente i pazianti MN idiopatiche.
Tutti i dati qui riportati dimostrano come l’utilizzo di moderne tecniche proteomiche per lo studio delle glomerulonefriti rappresenti un passaggio fondamentale nello studio di biomarcatori e del loro utilizzo in clinica sia a scopi diagnostici che prognostici.<br>Idiopathic glomerulonephritis (GN), such as membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS) and IgA nephropathy (IgAN) represent the most frequent primary Glomerular Kidney Diseases (GKDs) worldwide and are a common cause of end-stage renal disease (ESRD). Without the correct diagnosis and, ultimately, the correct selection of therapeutic treatment, the patient has a higher probability of progressing to ESRD and requiring dialysis or transplantation. Although the renal biopsy currently remains the gold standard for the routine diagnosis of idiopathic GN, the invasiveness and difficulty of diagnoses related with this procedure means that there is a strong need for the detection of diagnostic and prognostic biomarkers that can be translated into less invasive diagnostic tools.
Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is a unique proteomic technology that explores the spatial distribution of biomolecules directly in situ, thus integrating molecular and morphological information. The possibility to correlate distribution maps of multiple analyses with histological features makes it an ideal research tool to discover new diagnostic and prognostic markers. This modern proteomic technique could represent an invaluable tool in the field of nephropathology, most specifically in the study of primary glomerulonephritis (GNs), due to its potential to obtain proteomic signatures from pathological glomeruli and tubuli.
The body of work enclosed in this thesis follows the application of MALDI-MSI to fresh-frozen and formalin-fixed paraffin-embedded (FFPE) renal biopsies in order to detect diagnostic and prognostic molecular markers associated with the most common forms of glomerulonephritis. More specifically, MALDI-MSI was applied to fresh frozen bioptic renal tissue from patients with a histological diagnosis of FSGS (n=6), IgAN, (n=6) and MN (n=7), and from controls (n=4) in order to detect specific molecular signatures of primary glomerulonephritis. MALDI-MSI was able to generate molecular signatures capable to distinguish between normal kidney and pathological GN, with specific signals (m/z 4025, 4048 and 4963) representing potential indicators of CKD development. Moreover, specific disease-related signatures (m/z 4025 and 4048 for FSGS, m/z 4963 and 5072 for IgAN) were detected. Of these signals, m/z 4048 was identified as α-1-antitrypsin (A1AT) and was shown to be localised to the podocytes within sclerotic glomeruli by immunohistochemistry and could potentially be one of the markers of podocyte stress that is correlated with the development of FSGS.
Furthermore, a protocol for the analysis of FFPE renal biopsies was developed and optimised. Using this optimised protocol, MALDI-MSI was applied to renal biopsies from histologically diagnosed primary and secondary MN patients (n=20) in order to evaluate the capability of this technology to detect alterations in their tissue proteome. MALDI-MSI was able to generate molecular signatures of primary and secondary MN, with one particular signal (m/z 1459), identified as Serine/threonine-protein kinase MRCK gamma, being over-expressed in the glomeruli of primary MN patients with respect to secondary MN. Furthermore, this proteomic approach detected a number of signals that could differentiate the different forms of iMN (m/z 1094, 1116, 1381 and 1459). These signals could potentially represent future targets to be investigated as proteomic markers for the further stratification of iMN patients.
The findings presented here highlight how the study of glomerular diseases using this modern proteomic technology shows vast potential and may eventually herald an era where these findings are translated for use within a clinical context, either for diagnostic or prognostic purposes.
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Balluff, Benjamin. "MALDI imaging mass spectrometry in clinical proteomics research of gastric cancer tissues." Diss., lmu, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-155986.
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Flatley, Brian. "Utilisation of mass spectrometry in the quest for male urogenital cancer biomarkers." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632862.
Full textAbstract:
This thesis presents the application of mass spectrometry to the field of biomarker discovery. It focuses on the identification of diagnostic and prognostic protein biomarkers for prostate and penile cancer respectively. Matrix-assisted laser desorption/ionisation (MALDI) and electro spray ionisation (ESI) are key ionisation techniques used in mass spectrometry for the analysis of macromolecules such as proteins. High-throughput MALDI mass spectrometry profiling was used to analyse urine and plasma samples from men attending a urology clinic for confirmation of their prostate disease status. The results of the MALDI MS profiling found that the abundance of p-microseminoprotein (MSMB) when measured in urine taken following a digital rectal examination of the prostate gland was lower in men with prostate cancer over men that were diagnosed with benign prostate conditions. MALDI MS was also used to map the spatial distribution of biomolecules in penile tissue slices that contained invasive squamous epithelial cell carcinoma and areas of benign epithelial cells. The results of this mapping highlighted a number of mass-to-charge (mlz) ratios where the abundance of the underlying biomolecule was significantly different in one region when compared to the other. One difference at mlz 11,637 was suggested to represent the calcium binding protein family member SIOOA4. The levels of this protein were measured in a larger sample cohort using immunohistochemistry, where it was found that the number of epithelial cells in malignant penile tissue that were positive for SlOOA4 could be correlated to the clinical grade assigned to that tumour.
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Djidja, Marie-Claude. "Examination of tumour tissues by direct MALDI-mass spectrometry imaging and profiling." Thesis, Sheffield Hallam University, 2009. http://shura.shu.ac.uk/20662/.
Full textAbstract:
The purpose of the work described in this thesis was to develop and apply efficient methodologies based on MALDI-MSI for the direct analysis and targeting of protein tumour biomarkers within both frozen and formalin fixed paraffin embedded (FFPE) cancerous tissue sections. Method development for protein analysis directly in tumour tissue sections were performed using tumour xenograft models. This involved improvements in sample preparation, such as tissue washing protocols, and the development of data pre-processing methods prior to statistical analysis using a freely available software package, which referred to as Spec Align. The use of MALDI-MSI for studying proteome patterns directly from tumour tissue sections with no requirement for known targets is demonstrated. In addition, in situ identification of proteins within tumour tissue sections was achieved and correlated with their localisation. The method demonstrated here involved the use of octyl glucoside, a non-ionic detergent, which aims to improve the solubilisation and detection of low abundance and membrane-associated proteins within tumour tissue section after on-tissue digestion. The coupling of MALDI-MSI with ion mobility separation (IMS) has been found to improve the specificity and selectivity of the method. Combining these two methodological approaches allowed the targeting and identification of known tumour biomarkers and potential protein markers in various tumour tissue samples including frozen AQ4N dosed colon tumour xenografts and FFPE human adenocarcinoma tissue sections. The localisation and identification of proteins correlated to tumour growth and aggressiveness were studied using IMS-Tag MALDI-MSI, a novel concept developed in this work. In order to demonstrate its use as a potential biomarker discovery tool, MALDI-MSI was used for high throughput analysis of proteins within tissue micro arrays. Combining MALDI-MSI with statistical analysis allowed the design of a novel tumour classification model based on proteomic imaging information after on-tissue digestion. Another challenge for the MALDI-MSI technology is to achieve more targeted quantitative approaches for in situ analysis of proteins. A proof-of-concept based on multiple reaction monitoring (MRM) analysis with MALDI-MSI is described using a high repetition rate solid state laser. This aimed to improve the sensitivity and specificity of the methodology for the investigation of peptides/proteins directly within tumour tissue sections.
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Tummala, Manorama. "Surfactant-Aided Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (SA-MALDI MS)." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100672049.
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Broscoe, Molly. "`Who’s the Alpha Male Now Bitches’: Masculinity Narratives in Mass Murder Manifestos." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1626357258853525.
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Saraiva, Bruno Manuel Santos. "Identification of bacteria by mass spectrometry." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14317.
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Mestrado em Bioquímica - Métodos Biomoleculares<br>Identification of bacteria is a major part of the diagnosis of a pathogenic infection. In order to positively and confidently identify the bacteria, different techniques can be applied. These techniques are based on different principles, such as phenotypic differences, DNA sequences comparison, mass spectrometry (MALDI-TOF) and the protein content of the bacteria. From comparison of MALDI-TOF for bacteria identification with the other methodologies available, several advantages can be highlighted: lower cost per identification, faster results and higher discrimination power.
This work focus on the development of a new application capable of identifying bacteria using MALDI-TOF mass spectrometry. It started by the protein extraction of the samples and the acquisition of the mass profiles of those bacteria. This work proceeded with the development of an application to identify bacteria by comparing the mass profile of an unknown sample with the mass profiles of the bacteria in our database.
Using the developed application it was possible to identify both Gram-positive and Gram-negative bacteria to the strain-level. When an identification to strain-level was not possible, it was possible to identify the bacteria to the species-level and in the case the database did not contain an entry of the same species as the sample, the score values were low enough to disregard a possible identification resulting in a low false-positive rate.<br>A identificação de bactérias é um dos principais componentes do diagnóstico de infeções patogénicas. De modo a se conseguir obter uma identificação podem ser aplicadas diferentes técnicas, tais como, diferenças de fenótipo, comparação de sequências de ADN e a comparação do conteúdo proteico das bactérias. Quando se compara a identificação bacteriana com recurso à espectrometria de massa MALDI-TOF com as metodologias alternativas, podemos destacar diversas vantagens: menor custo por análise, menos tempo para obtenção de resultados e um maior poder discriminatório.
Este trabalho tem como foco o desenvolvimento de uma nova aplicação capaz de identificar bactérias com recurso a espectrometria de massa. O trabalho foi iniciado com a extração proteica das amostras e a aquisição dos perfis de massa dessas bactérias. De seguida, prosseguiu-se com o desenvolvimento de uma aplicação para a identificação de bactérias com base na comparação dos perfis de massa da amostra e dos perfis contidos na base de dados.
Usando a aplicação desenvolvida conseguiu-se identificar corretamente tanto bactérias Gram-positivas como Gram-negativas. Quando uma identificação da estirpe não foi possível, a aplicação permitiu a identificação da espécie bacteriana e no caso de a base de dados não conter nenhuma entrada que correspondesse a estirpe ou espécie da amostra, os scores obtidos eram suficientemente baixos para uma eventual identificação ser descartada, resultando assim numa baixa taxa de falsos positivos.
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IVANOVA, MARIIA. "Advanced proteomics MALDI-MSI imaging in chronic glomerulonephrites: from diagnostics to precision medicine." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/263391.
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Chronical kidney disease (CKD) is a worldwide health problem with increasing incidence, where the major part accounts for chronic glomerulonephrites (GN). It is a group of diseases of various aetiology and multiform clinical course, having various prognosis which is often hardly predictable as well as existing prognostic markers are not always certain. There is an urging need of new reliable and specific prognostic and therapeutic markers research. A modern proteomic technology - Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has been employed in many GN studies showing promising results.
We aimed to study several forms of primary and secondary glomerulonephrites (membranous nephropathy, IgA nephropathy, diabetic nephropathy) to enlighten possible molecular alterations significant of diseases’ progression. The studies were performed on renal tissue biopsies, analysing them with high spatial resolution MALDI-MSI to get better visualisation of signals’ co-localisation on tissue. We performed a comparison of molecular profiles of various forms of GN. As a result, we were able to generate and distinguish specific tryptic peptides profiles of different cell regions (tubules, glomeruli, interstitium, connective tissue) and detect proteins with an altered intensity, implicated in inflammatory and healing pathways.
MALDI-MSI, being able to define renal structures, could provide additional diagnostic and prognostic information. Generation of collective diagnostic panels may fulfil our pathogenesis understanding and assist clinical prognostic assessment.<br>Chronical kidney disease (CKD) is a worldwide health problem with increasing incidence, where the major part accounts for chronic glomerulonephrites (GN). It is a group of diseases of various aetiology and multiform clinical course, having various prognosis which is often hardly predictable as well as existing prognostic markers are not always certain. There is an urging need of new reliable and specific prognostic and therapeutic markers research. A modern proteomic technology - Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) has been employed in many GN studies showing promising results.
We aimed to study several forms of primary and secondary glomerulonephrites (membranous nephropathy, IgA nephropathy, diabetic nephropathy) to enlighten possible molecular alterations significant of diseases’ progression. The studies were performed on renal tissue biopsies, analysing them with high spatial resolution MALDI-MSI to get better visualisation of signals’ co-localisation on tissue. We performed a comparison of molecular profiles of various forms of GN. As a result, we were able to generate and distinguish specific tryptic peptides profiles of different cell regions (tubules, glomeruli, interstitium, connective tissue) and detect proteins with an altered intensity, implicated in inflammatory and healing pathways.
MALDI-MSI, being able to define renal structures, could provide additional diagnostic and prognostic information. Generation of collective diagnostic panels may fulfil our pathogenesis understanding and assist clinical prognostic assessment.
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PENG, LIJUAN. "MATRIX-ASSISTED LASER DESORPTION/IONIZATION (MALDI) TARGET MODIFICATION FOR ENHANCED PROTEOMICS ANALYSIS AND PLASMA POLYMER CHARACTERIZATION BY MALDI MASS SPECTROMETRY." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/dissertations/207.
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The work described in this dissertation is divided into three sections. In the first section three surface modifications are used to produce MALDI targets having reduced surface-protein binding affinity with a goal of increasing peptide/protein MALDI ion signals and lowering the limits of detection (LODs) for proteins and peptides. The second section discusses a bioselective MALDI target, produced via radio frequency (rf) plasma deposited ethylenediamine (EDA), for on-target separation of complex protein mixtures. The third section develops a new approach for characterization of rf plasma-deposited bulk polymers by using MALDI MS. Previous studies in our group have shown that the analyte signal in a MALDI MS experiment is strongly influenced by the binding interactions between the target surface and the analyte. Specifically, the analyte signal increases with decreasing surface-analyte binding affinity, which has been attributed to more unbound analyte being available for incorporation within the MALDI matrix. In the presented studies MALDI targets are modified with polyethylene glycol (PEG)-like structures via chemical grafting of PEG onto polyurethane (PU) film and rf plasma polymerization of ethylene oxide vinyl ether (EO2) and tetraglyme. It is shown that there are enhancements in the protein MALDI ion signals on these modified targets and that the LOD for target proteins is decreased by a factor of 2-10 in comparison with the conventional stainless steel MALDI target. On-probe affinity capture (OPAC) MALDI MS, developed in our group, has shown that functional group modified MALDI targets can be used to rapidly and selectively isolate target analytes from complex samples. For applications involving analysis of complex peptide/protein mixtures, fractionation of the mixture on the basis of component pI can reduce MALDI ion suppression effects leading to efficient ionization of larger numbers of mixture components. In the present studies a MALDI target is modified by rf plasma deposition of polymerized EDA to yield an OPAC target suitable for capture of proteins with low pI (expected to be negatively charged at neutral pH). In subsequent MALDI MS analyses of both control and biological mixtures after fractionation on the OPAC target it is observed that a significant number of additional peptide/protein ion signals are detected. The results of these studies, along with studies of the effects of the density of the primary amine functionality on the bio-selective MALDI ion signals, are presented. The complex nature of the polymer films resulting from plasma polymerization makes it very difficult to characterize their molecular structures. The presented study is the first to use MALDI MS for characterization of rf plasma-deposited bulk polymers and for investigation of the rf plasma polymerization process. It is shown that the mass spectra of the soluble fraction of allyl alcohol, EO2 and ethylene glycol butyl vinyl ether -plasma polymers contain clear polymer series. Furthermore, it is found that the peaks of the EO2-plasma polymer series shift to higher molecular weight distribution with decreasing plasma duty cycle. In contrast to predictions based on conventional radical polymerization, the mass spectra of all three plasma polymers exhibit the same repeat unit of 44 Da, for which the most likely structure would be -(CH2CH2O)-.
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Scionti, Vincenzo. "Novel Applications of Mass Spectrometry on Synthetic Polymeric Materials." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1335149657.
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Bowman, Amber Suzanne. "ENHANCED ANALYSIS OF LIGNIN DEHYDROGENATION OLIGOMERS VIA MASS SPECTROMETRY." UKnowledge, 2018. https://uknowledge.uky.edu/chemistry_etds/104.
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Effective analytical techniques need to be developed to characterize the products of lignin degradation experiments to be able to generate renewable products from lignin. Mass spectrometry is an valuable analytical approach for lignin characterizaion, but it is hindered by lignin’s poor ionization efficiency, especially in the positive ion mode. In this work, we attempt to improve lignin’s ionization by utilizing electrospray and laser desorption mass spectrometry coupled with the addition of cations and chemical derivatives. We confronted the ionization problem from both a top-down and bottom-up analytical approach by analyzing synthesized monomers, dimers, and polymers along with natural lignin extracts from switchgrass. We also utilized tandem mass spectrometry to sequence lignin dimers and determine their bonding motifs from their fragmentation patterns. We believe that resolving the ionization issues with lignin will open the door for easier and more efficient lignin break-down techniques and ultimately more accessible renewable products from lignin.
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Myatt, Christopher Paul. "The development of a matrix-assisted laser desorption/chemical ionisation time-of-flight mass spectrometer." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340903.
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Hoteling, Andrew J. "MALD/I TOF PSD and CID : understanding precision, resolution, and mass accuracy and MALD/I TOFMS : investigation of discrimination issues related to solubility /." Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/318.
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Eriksson, Mikaela. "Conflict-related sexual violence against men: A thematic analysis of the phenomenon in mass media." Thesis, Linnéuniversitetet, Institutionen för samhällsstudier (SS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-100248.
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Conflict-related sexual violence against men is a largely unrecognized and forgotten perspective in both research and international policies. Reports document that conflict-related sexual violence affects men, yet detailed consideration of the issue remains missing due to the lack of comprehensive research. The existing research is scarce and focuses primarily on the policy perspective or call for increased attention towards recognizing the subject. This study has sought to increase the understanding of the phenomenon through the perspective of mass media. The objective of the study has been to examine how the subject is portrayed by the media, including how male survivors in media describe their own experiences of sexual violence regarding masculine norms and stigma. The study has been conducted as a qualitative desk study by using empirical data from news articles in online newspapers. The study has followed an abductive approach and applied an analytical framework consisting of the two theories Social Stigma and Hegemonic Masculinity. A thematic analysis was used to interpret the empirical data and three main themes were identified. The findings suggest that the subject tends to be portrayed as unusual or as an exceptional phenomenon. The news articles use similar words to describe the subject, such as hidden, silent, ignored, and underreported. The subject is also deeply associated with stigma and masculine norms, both by the survivors and in the articles. The male survivors tend to illustrate how they feel ashamed, humiliated and stigmatized as a result of their experiences. The survivors also reflect upon a sense of loss in their masculine identity and have either avoided speaking about it or been rejected by society due to normative masculine expectations.
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Broberg, Susanna. "Studies of oligo- and polysaccharides by MALDI-TOF and ESI-ITMSn mass spectrometry /." Uppsala : Dept. of Chemistry, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a452.pdf.
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Maurer, Katja. "Oral brush biopsy analysis by MALDI-ToF Mass Spectrometry for early cancer diagnosis." Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-116691.
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Objectives: Intact cell peptidome profiling (ICPP) with MALDI-ToF Mass-Spectrometry holds promise as a non invasive method to detect head and neck squamous cell carcinoma (HNSCC) objectively, which may improve the early diagnosis of oral cancer tremendously. The present study was designed to discriminate between tumour samples and non-cancer controls (healthy mucosa and oral lesions) by analysing complete spectral patterns of intact cells using MALDI-ToF MS.
Material and Methods: In the first step, a data base consisting of 26 patients suffering from HNSCC was established by taking brush biopsy samples of the diseased area and of the healthy buccal mucosa of the respective contralateral area. After performing MALDI-ToF MS on these samples, classification analysis was used as a basis for further classification of the blind study composed of additional 26 samples including HNSCC, oral lesions and healthy mucosa.
Results: By analyzing spectral patterns of the blind study, all cancerous lesions were defined accurately. One incorrect evaluation (false positive) occurred in the lesion cohort, leading to a sensitivity of 100%, a specificity of 93% and an overall accuracy of 96.5%.
Conclusion: ICPP using MALDI-ToF MS is able to distinguish between healthy and cancerous mucosa and between oral lesions and oral cancer with excellent sensitivity and specificity, which may lead to a more impartial early diagnosis of HNSCC.
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Williams, Bradley Allen. "LOCATING CHELERYTHRINE, AN ALKALOID, WITHIN A CYTOSOLIC ENVIRONMENT BY MALDI-TOF MASS SPECTROMETRY." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1389645518.
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Aboulmagd, Khodier Sarah. "Analysis of Lipids in Kidney Tissue Using High Resolution MALDI Mass Spectrometry Imaging." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19443.
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Massenspektrometrisches Imaging (MSI) ist unverzichtbar für die Untersuchung der räumlichen Verteilung von Molekülen in einer Vielzahl von biologischen Proben. Seit seiner Einführung hat sich MALDI zu einer dominierenden Bildgebungsmethode entwickelt, die sich als nützlich erwiesen hat, um die Komplexität von Lipidstrukturen in biologischen Geweben zu bestimmen.
Einerseits ist die Rolle von Cisplatin bei der Behandlung von menschlichen malignen Erkrankungen gut etabliert, jedoch ist Nephrotoxizität eine limitierende Nebenwirkung, die Veränderungen des renalen Lipidprofils beinhaltet. Dies führte zu der Motivation, die Lipidzusammensetzung des Nierengewebes in mit Cisplatin behandelten Ratten zu untersuchen, um die involvierten Lipid-Signalwege aufzuklären. Es wurde eine Methode zur Kartierung der Lipidzusammensetzung in Nierenschnitten unter Verwendung von MALDI MSI entwickelt. Die Verteilung von Nierenlipiden in Cisplatin-behandelten Proben zeigte deutliche Unterschiede in Bezug auf die Kontrollgruppen.
Darüber hinaus wurde die Beurteilung der Ionenbilder von Lipiden in Cisplatin-behandelten Nieren meist als qualitative Aspekte betrachtet. Relative quantitative Vergleiche wurden durch den variablen Einfluss von experimentellen und instrumentellen Bedingungen begrenzt. Daher bestand die Notwendigkeit, ein Normalisierungsverfahren zu entwickeln, das einen Vergleich der Lipidintensität verschiedener Proben ermöglicht. Das Verfahren verwendete einen Tintenstrahldrucker, um eine Mischung der MALDI-Matrix und der internen internen Lipid-Metall-Standards aufzubringen. Unter Verwendung von ICP-MS erlaubte der interne Metallstandard, die Konsistenz der Matrix und der internen Standards zu bestätigen. Die Anwendung der Methode zur Normalisierung von Ionenintensitäten von Nierenlipiden zeigte eine ausgezeichnete Bildkorrektur und ermöglichte einen relativen quantitativen Vergleich von Lipidbildern in Cisplatin-behandelten Proben.<br>Mass spectrometry imaging is indispensable for studying the spatial distribution of molecules within a diverse range of biological samples. Since its introduction, MALDI has become a dominant imaging method, which proved useful to sort out the complexity of lipid structures in biological tissues.
The role of cisplatin in the treatment of human malignancies is well-established. However, nephrotoxicity is a limiting side effect that involves an acute injury of the proximal tubule and alterations in the renal lipid profile. This evolved the motivation to study the spatial distribution of lipids in the kidney tissue of cisplatin-treated rats to shed light on the lipid signaling pathways involved. A method for mapping of lipid distributions in kidney sections using MALDI-LTQ-Orbitrap was developed, utilizing the high performance of orbitrap detection. The distribution of kidney lipids in cisplatin-treated samples revealed clear differences with respect to control group, which could be correlated to the proximal tubule injury. The findings highlight the usefulness of MALDI MSI as complementary tool for clinical diagnostics.
Furthermore, assessment of the ion images of lipids in cisplatin-treated kidney mostly considered qualitative aspects. Relative quantitative comparisons were limited by the variable influence of experimental and instrumental conditions. Hence, the necessity developed to establish a normalization method allowing comparison of lipid intensity in MALDI imaging measurements of different samples. The method employed an inkjet printer to apply a mixture of the MALDI matrix and dual lipid-metal internal standards. Using ICP-MS, the metal internal standard allowed to confirm the consistency of the matrix and internal standards application. Applying the method to normalize ion intensities of kidney lipids demonstrated excellent image correction and successfully enabled relative quantitative comparison of lipid images in control and cisplatin-treated samples.
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Page, Jennifer Renee'. "'And he shall be called woman': behind the mask of selected black male actors cross-dressing in entertainment." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2009. http://digitalcommons.auctr.edu/dissertations/98.
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This research explored Dunbar’s concept of the mask in order to examine why select black male actors, Flip Wilson (as Geraldine), Eddie Murphy (as Rasputia), Martin Lawrence (as Sheneneh), and Tyler Perry (as Madea), have worn the mask of femininity to survive the vicissitudes of the American stage. It explained what factors compelled these selected black male actors to mask their appearance and why the outward signs of femininity are used as vehicles of communication in their artistic expression. The methodology involved a visual deconstruction of media utilizing literary texts as the instrument to analyze the movies and television shows of these actors, and the research centered on the theories of W. E. B. Du Bois’ notions of the veil and double consciousness, Stephen Greenblatt’s idea of self-fashioning and self cancellation, and Franz Fanon’s views on language found in the book Black Skin White Masks. While wearing the mask, Wilson, Murphy, Lawrence, and Perry challenge society’s notion of black manhood, the limitation of the black man’s freedom of speech, and the role of black women in their plight for an uninhibited existence. These actors also tackle crucial matters, namely black female sexuality, classism, obesity, and the black family. These actors achieve their objective and combat the gaze of both black and white America by self-fashioning and self-canceling their identities at will.
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Eastwood, Stephanie. "Development of Amine Containing Polymer Modified MALDI Targets for Complex Peptide and Protein Mixture Fractionation Prior to MALDI Mass Spectrometry Analysis." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/948.
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AN ABSTRACT OF THE DISSERATION OF STEPHANIE EASTWOOD, for the Doctor of Philosophy degree in CHEMISTRY, presented on the DATE OF DEFENSE, at Southern Illinois University Carbondale. TITLE: DEVELOPMENT OF AMINE CONTAINING POLYMERIC MODIFIED MALDI TARGET SUBSTRATES FOR COMPLEX MIXTURE FRACTIONATION OF PEPTIDE AND PROTEIN MIXTURES PRIOR TO MALDI MASS SPECTROMETRY ANALYSIS MAJOR PROFESSOR: Dr. Gary Kinsel The focus of this dissertation is the synthesis, development and application of the amine containing modified targets for the fractionation of complex mixtures of peptides and digested proteins prior to MALDI-MS analysis. Even though MALDI-MS is increasingly used in proteomic applications and analysis, this method suffers from loss of performance in the analysis of mixtures, due to the ion suppression effect. In this effect, basic peptides ionize more readily than acidic peptides and there by suppress the ionization and detection of less basic peptides resulting in the loss in the detection of valuable sequence information and posttranslational modifications. In the approach taken, a modified target containing amine functionality was utilized as a mixture fractionation substrate. The substrates were chosen for the adsorption of targeted analytes. Incorporating this amine function into 3D brushes offer the ability to absorb higher quantities of peptides, allowing for a more thorough analysis and more sequence coverage. In this work fractionation occurs as the result of electrostatic attraction or repulsion between the positively charged polymer surface and negatively charged analytes in solution. Fractionation studies utilizing this amine chemistry for separation were done first with binary peptide mixtures. Basic peptides are observed to repel from the cationic polymer surfaces, allowing the suppressed acidic peptides to separate from the mixture by binding to the amine substrates. The acidic peptides can be eluted and observed. Following successful demonstrations, more complex mixtures of peptides derived from enzymatic tryptic digestion of proteins were studied. Following fractionation, MALDI mass spectra of both the washed and eluted fractions are obtained and ions signals are analyzed and associated with predicted peptide sequences. Complete analysis of the ion signals using Prowl and PeptideMap leads to a percent protein sequence coverage. Comparison of this number with the percent sequence obtained from unfractionated (conventional) digested peptide mixture mass spectra reveals that fractionation does in fact significantly increase and also increases discovery of post translational modifications (PTM). Fractionation studies were studied by varying the pH of tryptically digest proteins. Sequence coverages were found to increase upon fractionation at all pHs studied. In order to increase the discovery of PTMs, the cationic polymer brush was doped with copper ions to selectively capture phosphopeptides. Negatively charged phosphopeptides were shown to be selectively captured by the copper ions complexes within the polymer brush substrate, and subsequently released upon addition of acid.
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Hunsucker, Stephen Warren. "Time-of-Flight Mass Spectrometry to Characterize Inorganic Coordination Complexes and Cyanobacteria." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/27150.
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Matrix assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOFMS) is used to study several inorganic coordination complexes and a variety of compounds from cyanobacteria. Also presented is a discussion of TOFMS instrumentation and the improvements in resolution and instrument automation that have lead to widespread and diverse applications of MALDI-TOFMS in all areas of science.
The feasibility of using direct laser desorption/ionization (LDI) TOFMS to detect trace elements in a variety of glass samples using a lithium borate fusion technique for sample preparation is investigated. The result of the fusion technique is a homogeneous incorporation of the analytical sample into a glass. The fusion technique is investigated as a way to eliminate matrix effects in direct LDI-TOFMS analysis. However, the high concentration and low ionization potential of lithium suppress ionization of the elements of interest. The detection limits of elements in glass samples were not at the trace level. Therefore the technique is not as useful as well-established analytical methods like X-ray fluorescence and inductively coupled plasma mass spectrometry.
Direct laser ablation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of four inorganic coordination complexes are discussed. The compounds studied include [Ir(dpp)2Cl2](PF6), {[(bpy)2Ru(dpp)]2RuCl2}(PF6)4, [(tpy)Ru(tpp)Ru(tpp)RhCl3](PF6)4 and {[(bpy)2Ru(dpp)]2IrCl2}(PF6)5 (dpp = 2,3-bis-(2'-pyridyl)-pyrazine, bpy = 2,2'-bipyridine, tpy = 2,2',6',2"-terpyradine, tpp = 2,3,5,6,-tetrakis-(2'-pyridyl)-pyrazine). Spectral intensities and fragmentation patterns are compared and evaluated for several instrument parameters, matrices, and matrix-to-analyte ratios. Direct ablation and MALDI mass spectra of the monometallic complex showed the same ion peaks and differed only in the relative peak intensities. Direct ablation of the trimetallic complexes produced only low-mass fragments containing one metal atom at most. MALDI spectra of the trimetallic complexes exhibited little fragmentation in the high-mass region (>1500 Da) and less fragmentation in the low-mass region compared to direct laser ablation. Proper matrix selection for MALDI analysis was vital, as was an appropriate matrix-to-analyte ratio. The results demonstrate the applicability of MALDI-TOF mass spectrometry for the structural characterization of labile inorganic coordination complexes. A correlation is made between the gas-phase redox chemistry in the MALDI plume and the solution phase electrochemistry for this series of complexes.
MALDI-TOFMS was also used to study compounds isolated from cyanobacteria. A MALDI screening method has been developed to detect the presence of scytonemin, a UV-absorbing pigment. Detection of scytonemin is accomplished by a simple solvent extraction of cyanobacteria in the desiccated state with subsequent MALDI-TOFMS analysis. The method is rapid and semi-quantitative. Cyanobacteria is the only known organism to produce scytonemin, and it is only produced when the organism is subjected to UV stress. Laboratory-grown cultures were subjected to different amounts of UV radiation, and the screening method was used to detect the presence or absence of scytonemin. Cultures grown under ambient conditions (low UV) did not show the presence of scytonemin, while those grown under UV lamps did show the detectable scytonemin. Because scytonemin acts as a biomarker for UV stress, the MALDI screening method could find application in molecular ecology studies of cyanobacteria.
Peptide mass fingerprinting is used to monitor the isolation of the water stress protein from N. commune. The protein is produced by recombinant growth in E. coli in order to assess the role of Wsp in the desiccation tolerance of N. commune. The results show that SDS-PAGE and Western blot analysis are not sufficient to detect the presence of Wsp after purification using ion-exchange chromatography. Three E. coli proteins were identified in the same molecular weight range as Wsp and one of them cross-reacts with the series of antibodies used for the Western blot. The presence of contaminating proteins that cross-react with the immuno assay make it difficult to determine which fractions contained Wsp. Peptide mass fingerprints were obtained for a series of fractions collected after ion-exchange chromatography to pinpoint the location of Wsp. Peptide mass fingerprinting was also used to monitor the stability of the clone and results show that the clone is modified over a six month period.<br>Ph. D.
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Kuba, Pavel. "Zpracování a vizualizace dat z hmotnostního spektrometru typu TOF-MALDI." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230019.
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This thesis describes the development of control applications for the deposition machine and mass spectrometer. Thesis describes operation principles of both devices and their hardware specifications. Thesis also describes the design of developed applications. Functionality was tested on series of real measurements.
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Djidja, M.-C., V. A. Carolan, Paul M. Loadman, and M. R. Clench. "Method development for protein profiling in biological tissues by matrix-assisted laser desorption/ionisation mass spectrometry imaging." Wiley, 2008. http://hdl.handle.net/10454/4568.
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Nicholls, E. Henry. "Male adaptations to sperm competition in the sand martin Riparia riparia." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322914.
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Payne, Liên Kyle Greeley Arthur. "A study of newspaper treatment of male and female political candidates." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6546.
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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on November 20, 2009). Thesis advisor: Greeley Kyle. Includes bibliographical references.
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Akinapalli, Srikanth. "MICROFLUIDIC DYNAMIC ISOELECTRIC FOCUSING COUPLED TO MATRIX ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/dissertations/1289.
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Proteomics is an increasingly important area of biological research and has gathered much attention over recent years. Major challenges that make a proteomic analysis difficult are sample complexity, diversity and dynamic range. Progress in the area of proteomics relies heavily on new analytical tools for the sensitive, selective, and high-throughput studies of target analytes. It is estimated that there are several hundred thousand proteins in a human cell. In order to be able to analyze such a complex sample, an analytical method must be capable of separating and detecting many different sample peaks. The complexity of such samples indicates that a single separation method will not be able to provide the needed resolution. If two methods that are orthogonal are combined, then the peak capacity of the combined system is the product of the two individual peak capacities. Development of such systems would cater to the current demands of proteomics studies. Matrix assisted laser desorption/ionization (MALDI) mass spectrometry has evolved into a primary analytical tool for proteomics research. MALDI is fast and efficient and has a high tolerance to non-volatile buffers and impurities. The samples for MALDI are typically applied to solid supports after having been subjected to off-line liquid or gel separations. Several methods have been reported involving various chromatographic or electrophoretic separation methods. However, the current methods often require highly sophisticated sample handling systems, which are often expensive and in need of skilled human resources. The current demands of proteomic analyses require fast, efficient and inexpensive methods for separation to fully harness the capability of MALDI mass spectrometry. In this work a microfluidic device has been designed to perform dynamic isoelectric focusing (DIEF) based protein separation with digital sample deposition directly on a MALDI target for offline analysis. DIEF is related to capillary isoelectric focusing which and can facilitate the interface without the loss of the separation resolution. Compared to traditional capillary isoelectric focusing (cIEF) DIEF uses additional high-voltage power supplies to control the pH gradient by manipulating the electric field. The proteins can be focused at a desired sampling position according to their isoelectric point, to be collected for further analysis by MALDI mass spectrometry. DIEF has a peak capacity of over a thousand and offers an ease of interfacing to other techniques making it a preferred separation method for the interface with mass spectrometric techniques such as MALDI. The design of the microfluidic device is based on a digital droplet fractionation. Multiple fractions of the sample solution from DIEF are generated to retain the resolution and to act as an additional separation mode. The microfluidic device is controlled by actuating pneumatic valves built into the device. The DIEF operational parameters were optimized according to the surface functionality and the design of the microfluidic device. A suitable MALDI sample preparation method was found by studying different existing methods. The methods were studied using test proteins prepared in solutions having the additives used in the experiment. A simple mixture of three proteins was used to demonstrate the application of the developed method. The separation between the proteins insulin, hemoglobin and the myoglobin was demonstrated by varying the separation resolution in three experiments.
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Parmar, D. S. "High resolution mass spectrometry based quantification in metabolomics." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4562.
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Longhenry, Vern. "Differences in representation of male and female roles in television advertising." Online version, 2002. http://www.uwstout.edu/lib/thesis/2002/2002longhenryv.pdf.
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Friess, Sebastian D. "Surface topology probing of biomolecules unsing noncovalent receptors : A dissetration on MALDI mass spectrometry /." Zürich, 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15336.
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