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- Fletcher, John, 1978, et al.
(författare)
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ToF-SIMS Studies of Sulfuric Acid Hydrate Films
- 2004
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Ingår i: Journal of Physical Chemistry B. - 1520-5207 .- 1520-6106. ; 108:19, s. 5960-5966
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Tidskriftsartikel (refereegranskat)abstract
- A variety of sulfuric acid hydrate films, formed by the co-deposition of SO3 and H2O on a cooled substrate, have been analyzed using time-of-flight secondary ion mass spectrometry (ToF-SIMS). The films were produced using procedures developed in recent infrared spectroscopic studies. Spectra have been shown to consist of a series of identifiable fragments, the change in intensities of which can be related to changes in temperature and the relative abundance of H2O during the deposition of the film under UHV conditions. Depth profiling of the films shows clear evidence of separate surface species on some films and supports the existence of surface molecular hydrates over a stable bulk hydrate film
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- Fletcher, John, 1978, et al.
(författare)
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Uncovering new challenges in bio-analysis with ToF-SIMS
- 2008
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 255:4, s. 1264-1270
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Konferensbidrag (refereegranskat)abstract
- The introduction of cluster ion beams for routine SIMS analysis has greatly improved the prospects for characterising biological samples. The ultimate quality of the secondary ion image remains limited by the efficiency of the primary beam. Without overcoming the low ionisation probabilities associated with SIMS, the highest lateral resolution available for molecular imaging becomes limited by the statistical probability of any ions being generated from the area of the pixel. C(60)(+) primary ions are currently the most efficient available for routine analysis but although commercial systems have been demonstrated to produce spot sizes under 200 nm, focusing the beam produced in such electron impact sources results in rather low ion currents. The time scale for such high lateral resolution analysis can become impractical on conventional time-of-flight instruments. Molecular depth pro. ling capability has been revealed using SF(5)(+) and C(60)(+) ion beams and recent work has advanced the technique by combining the pro. ling and imaging abilities of these high efficiency projectiles to generate 3D molecular maps of biological systems. In this paper we discuss the challenges associated with 2D and 3D bio-analysis with emphasis on how instrumental advances aid such investigations yet demonstrating the obstacles that need to be overcome using a range of model and real world biological samples. We discuss complications with the biological matrix, challenges in manipulating and visualising the data and look at how instrumental advantages might aid the routine generation of these 3D molecular maps. (C) 2008 Elsevier B. V. All rights reserved.
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- Kotze, Helen L., et al.
(författare)
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ToF-SIMS as a tool for metabolic profiling small biomolecules in cancer systems
- 2013
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Ingår i: Surface and Interface Analysis. - 1096-9918 .- 0142-2421. ; 45:1, s. 277-281
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is emerging as a tool for studying the metabolism of disease. ToF-SIMS enables chemical specificity in addition to high spatial resolution imaging of biological samples from cells to tissue. Here, ToF-SIMS has been used to investigate the metabolic regulation of hypoxia-induced chemoresistance to doxorubicin treatment using multicellular tumour spheroids. Imaging principal component analysis (PCA) was used as a tool to identify the regions of chemistry present within the image that differ as a result of drug treatment. A series of metabolite ToF-SIMS spectra were acquired, which were used to identify quasi-molecular ions and fragments correlated to the PCA loading plots. Metabolite patterns have been identified as potential biomarkers of hypoxia-induced chemoresistance.
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- Tian, Hua, et al.
(författare)
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Spatiotemporal lipid profiling during early embryo development of Xenopus laevis using dynamic Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) Imaging
- 2014
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Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; Epub ahead of print
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) imaging has been used for the direct analysis of single intact Xenopus laevis (X. laevis) embryo surfaces, locating multiple lipids during fertilisation and the early embryo development stages with sub-cellular lateral resolution (~4 Microns). The method avoids the complicated sample preparation for lipid analysis of the embryos, which requires selective chemical extraction of a pool of samples and chromatographic separation, while preserving the spatial distribution of biological species. The results show ToF-SIMS is capable of profiling multiple components (e.g., glycerophosphocholine, sphingomyelin, cholesterol, vitamin E, diacylglycerol, triacylglycerol) in a single X. laevis embryo. We observe lipid remodelling during fertilisation and early embryo development via time course sampling. The study also reveals the lipid distribution on the gametes fusion site. The methodology used in the study opens the possibility of studying developmental biology using high resolution imaging MS and of understanding the functional role of the biological molecules.
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- Vaidyanathan, Seetharaman, et al.
(författare)
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Exploratory analysis of TOF-SIMS data from biological surfaces
- 2008
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332. ; 255:4, s. 1599-1602
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Konferensbidrag (refereegranskat)abstract
- The application of multivariate analytical tools enables simplification of TOF-SIMS datasets so that useful information can be extracted from complex spectra and images, especially those that do not give readily interpretable results. There is however a challenge in understanding the outputs from such analyses. The problem is complicated when analysing images, given the additional dimensions in the dataset. Here we demonstrate how the application of simple pre-processing routines can enable the interpretation of TOF-SIMS spectra and images. For the spectral data, TOF-SIMS spectra used to discriminate bacterial isolates associated with urinary tract infection were studied. Using different criteria for picking peaks before carrying out PC-DFA enabled identification of the discriminatory information with greater certainty. For the image data, an air-dried salt stressed bacterial sample, discussed in another paper by us in this issue, was studied. Exploration of the image datasets with and without normalisation prior to multivariate analysis by PCA or MAF resulted in different regions of the image being highlighted by the techniques. (C) 2008 Elsevier B. V. All rights reserved.
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