2,208 research outputs found
Analysis of hydrocarbon bearing fluid inclusions HCFI) using time-resolved fluorescence spectroscopy
No full textHydrocarbon-bearing fluid inclusions (HCFI) are microscopic cavities within rocks that are filled with petroleum oil, the composition of which may not have changed since the trapping event. Thus, the composition of that entrapped oil can provide information about the formation and evolution of the oil reservoir. This type of information is important to the petroleum production and exploration industries. Crude oil fluorescence originates from the presence of cyclic aromatic compounds and the nature of the emission is governed by the chemical composition of the oil. Fluorescence based methods are widely used for analysis of crude oil because they offer robust, non-contact and non-destructive measurement options. The goal of our group is the development of a non-destructive analytical method for HCFI using time-resolved fluorescence methods. In broad terms, crude oil fluorescence behavior is governed by the concentration of quenching species and the distribution of fluorophores. For the intensity averaged fluorescence lifetime ( τ ), the best correlations have been found between polar or alkane concentrations, but these are not suitable for robust, quantitative analysis. We have recently started to investigate another approach for characterizing oils by looking at Time-resolved Emission Spectra (TRES). TRES are constructed from intensities sampled at discrete times during the fluorescence decay of the sample. In this study, TRES, from a series of 10 crude oils from the Middle East, have been measured at discrete time gates (0.5 ns, 1 ns, 2 ns, 4 ns) over the 450-700 nm wavelength range. The spectral changes in TRES, such as time gate dependent Stokes shift and spectral broadening, are analyzed in the context of energy transfer rates. In this work, the efficacy of using TRES for fingerprinting individual oils and HCFI is also demonstrated.National Center for Biomedical Engineering Science as part of Higher Education Authority’s Programme for
Research in Third Level Institutions.non-peer-reviewe
CCDC 1489270: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
CCDC 1489268: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
CCDC 1489267: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
CCDC 1489265: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
CCDC 1489269: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
CCDC 1489266: Experimental Crystal Structure Determination
No full textRelated Article: Edel Houton, Brian Kelly, Sergio Sanz, Eric J. L. McInnes, David Collison, Euan K. Brechin, Anne-Laure Barra, Alan G. Ryder, Leigh F. Jones|2016|Eur.J.Inorg.Chem.||5123|doi:10.1002/ejic.20160112
Alan Moore Comics as Performance, Fiction as Scalpel
No full textEclectic British author Alan Moore (b. 1953) is one of the most acclaimed and controversial comics writers to emerge since the late 1970s. He has produced a large number of well-regarded comic books and graphic novels while also making occasional forays into music, poetry, performance, and prose. In Alan Moore: Comics as Performance, Fiction as Scalpel , Annalisa Di Liddo argues that Moore employs the comics form to dissect the literary canon, the tradition of comics, contemporary society, and our understanding of history. The book considers Moore's narrative strategies and pinpoints the main thematic threads in his works: the subversion of genre and pulp fiction, the interrogation of superhero tropes, the manipulation of space and time, the uses of magic and mythology, the instability of gender and ethnic identity, and the accumulation of imagery to create satire that comments on politics and art history. Examining Moore's use of comics to scrutinize contemporary culture, Di Liddo analyzes his best-known works-- Swamp Thing, V for Vendetta, Watchmen, From Hell, Promethea , and Lost Girls . The study also highlights Moore?s lesser-known output, such as Halo Jones, Skizz , and Big Numbers , and his prose novel Voice of the Fire. Alan Moore: Comics as Performance, Fiction as Scalpel reveals Moore to be one of the most significant and distinctly postmodern comics creators of the last quarter-century.Intro -- Contents -- Preface and Acknowledgments -- Introduction -- CHAPTER 1. Formal Considerations on Alan Moore's Writing -- CHAPTER 2. Chronotopes: Outer Space, the Cityscape, and the Space of Comics -- CHAPTER 3. Moore and the Crisis of English Identity -- CHAPTER 4. Finding a Way into Lost Girls -- Conclusion -- Notes -- Bibliography -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- Q -- R -- S -- T -- U -- V -- W -- Y -- ZEclectic British author Alan Moore (b. 1953) is one of the most acclaimed and controversial comics writers to emerge since the late 1970s. He has produced a large number of well-regarded comic books and graphic novels while also making occasional forays into music, poetry, performance, and prose. In Alan Moore: Comics as Performance, Fiction as Scalpel , Annalisa Di Liddo argues that Moore employs the comics form to dissect the literary canon, the tradition of comics, contemporary society, and our understanding of history. The book considers Moore's narrative strategies and pinpoints the main thematic threads in his works: the subversion of genre and pulp fiction, the interrogation of superhero tropes, the manipulation of space and time, the uses of magic and mythology, the instability of gender and ethnic identity, and the accumulation of imagery to create satire that comments on politics and art history. Examining Moore's use of comics to scrutinize contemporary culture, Di Liddo analyzes his best-known works-- Swamp Thing, V for Vendetta, Watchmen, From Hell, Promethea , and Lost Girls . The study also highlights Moore?s lesser-known output, such as Halo Jones, Skizz , and Big Numbers , and his prose novel Voice of the Fire. Alan Moore: Comics as Performance, Fiction as Scalpel reveals Moore to be one of the most significant and distinctly postmodern comics creators of the last quarter-century.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Anisotropy Resolved Multidimensional Emission Spectroscopy (ARMES) for the analysis of Immunoglobulin G (IgG) type proteins
No full textImmunoglobulin G (IgG) is the main antibody used in the biopharmaceutical industry for therapeutic purposes. Monoclonal antibodies (mAb) are growing in the marked due to its high specificity and safety. Physical and chemical stresses can lead to unfolding of the tertiary structure, which could then refold into a different structure, and/or aggregate. Changes in protein structure are dangerous and can cause adverse immunogenicity issues. One key factor to ensure efficacy and safety is to understand and measure the stability of mAbs in solution. A combination of different analytical techniques, some of them are expensive and time consuming, is necessary to monitor mAbs stability, and to assess protein aggregation. The aim of this project was to apply a newly developed fluorescence-based method, Anisotropy Resolved Multidimensional Emission Spectroscopy (ARMES), for the rapid characterisation of IgG type proteins in solution, which could be used to monitor IgG structure. This method combined polarized multidimensional fluorescence spectroscopy (pMDF), anisotropy, and chemometric analysis, such as Parallel factor analysis (PARAFAC), to try to resolve emission from different fluorophores, which were used to follow protein structure.
ARMES measurements of IgG solutions in its native state were carried out with polarized Excitation Emission Matrix (pEEM) and polarized Total Synchronous Fluorescence Spectroscopy (pTSFS) measurements. It was the first time that PARAFAC analysis was attempted on IgG, as there was no consensus about the optimal pre-processing method for this type of data, we evaluated several methods. Although there was insufficient fluorescence fluctuation in the native state for PARAFAC analysis to resolve different fluorophore populations, we were able to photophysically characterise the IgG, which served as a baseline for monitoring protein stability using ARMES. Thus, for the IgG protein, even if ARMES could not recover individual fluorophore emission, it was showed to be a suitable technique for monitoring protein stability
Bioprocess monitoring using Polarised Multidimensional Fluorescence (pMDF) spectroscopy
No full textBioprocess monitoring is essential for biopharmaceutical manufacturing as it helps to ensure the required quality of the therapeutic proteins and maximise the productivity of the bioprocess as per Quality-by-Design (QbD) principles. The monitoring of critical process parameters (CPPs) such as viable cell density and protein quantification is complicated by the complex chemical composition of the bioreactor broth. This thesis presents the systematic development and application of polarised multidimensional fluorescence (pMDF) spectroscopy as an analytical technique for bioprocess monitoring.First, we show the early-stage development and optimization of a polarised Total Synchronous Fluorescence Spectroscopy (pTSFS) method for protein quantification in a hydrolysate-protein model (mimics clarified bioreactor broth samples) using a standard benchtop laboratory fluorometer. We used UV transmitting polarizers to provide wider range pTSFS spectra for screening of the four different TSFS spectra generated by the measurement. We identified TSFS||(parallel polarised) measurements were the best for protein quantification compared to standard unpolarized measurements and the Bradford assay. This was because TSFS||spectra had a better analyte signal to noise ratio (SNR), due to the anisotropy of protein emission making protein signals better resolved from the background emission of small molecule fluorophoresin the cell culture media. SNR of > 5000 was achieved for concentrations of BSA/YST 1.2/10 g L–1with TSFS||. Optimisation using genetic algorithm and interval Partial Least Squares based variable selection enabled reduction of spectral resolution and number of excitation wavelengths required without degrading performance. This enables fast (<3.5 minutes) online/at-line measurements, and the method had an LOD of 0.18 g L–1and high accuracy with predictive error of <9%. Next, we evaluate the relative efficacy of polarised MDF methods such Excitation Emission Matrix (EEM), TSFS, and Resonant/90° Light Scattering (RLS) spectroscopy (90LSS) measurements for the quantitative analysis of a more complex, multi-protein bioreactor broth model using chemometricmethods including Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression. TSFS||measurements yielded predictive accuracies of % REP = 11% for total protein and % REP = 12% for IgG quantification.For this system we also realised that EEMǁmeasurements, being more sensitive to light scatter contamination were less robust compared toEEM⊥. Normalised RLS||was more accurate in predicting the total protein concentration (%REP = 14%) compared to specific IgG quantification (%REP = 20%) due to the difference in size between BSA and IgG.In our final study we evaluate the application of pMDF in biopharmaceutical process development which often involves the use of small-scale bioreactors (SSBR) for optimising media formulations and process conditions during scale up to commercial scale production. Specifically, we explore the efficacy of polarised total synchronous fluorescence spectroscopy (pTSFS) and Resonant Light Scattering (RLS) to qualitatively monitor and quantitatively predict titre and VCD respectively in a large-scale media optimisation SSBR study. The study involved 71 different media formulations, with over 50 components of varying concentrations, and the bioprocess was run for 13 days or more. Samples were extracted at set times (Day 0, 3, 6, 9, and 13), clarified by centrifugation, and then measured using pTSFS and RLS. These showed significant decrease in fluorescence intensity, changes in spectral profile and increased light scatter over the bioprocess. However, simple mean and standard deviation analysis and Principal component analysis (PCA) of the pTSFS data showed that the degree of variation was greater between media formulations than due to the evolving bioprocess. Spectral clustering methods were used to generate sample subsets for more accurate PLS regression modelling for real time monitoring of CPPs. Classification methods were used to predict the product titer at day 9 from the fluorescence spectra measured at the start of the bioprocess (day 0) with acceptable accuracy. RLS|| measurements correlated well with DLS and showed the potential in predicting VCD in future samples with less variation in media composition such as in actual commercial manufacturing bioprocess. Combining emission and scatter measurements with multivariate data analysis provides a more holistic, multi-attribute bioprocess monitoring method that minimises the need to use different offline analytical methods. We believe this approach will be very valuable for optimising media compositions with potential for high productivity while avoiding the cost of running to completion media formulations that results in poor productivity2026-06-0
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