The Practice Of Tof Sims
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The Practice Of Tof Sims
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Author : Alan M. Spool
language : en
Publisher: Momentum Press
Release Date : 2016-03-24
The Practice Of Tof Sims written by Alan M. Spool and has been published by Momentum Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-03-24 with Technology & Engineering categories.
Time of flight secondary ion mass spectrometry, TOF-SIMS, is a highly surface sensitive analytical technique that provides information about composition with submicron lateral resolution. For select materials, TOF-SIMS provides unparalleled sensitivity along with excellent reproducibility, and as a mass spectrometric technique, it also provides excellent specificity. Of the analytical methods available, it is among the most surface sensitive, but the physical principles that underlie it are also the least understood. This volume describes the instrumentation, the physical principles behind the technique to the extent they are understood, and provides a practical approach for the interpretation of TOF-SIMS data. The use of advanced data processing methods such as multivariate statistics are described in a readily approachable manner. Given a basic background in undergraduate chemistry and physics, the book will be of use to any student with an interest in the technique.
Principles And Practice Of Analytical Techniques In Geosciences
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Author : Kliti Grice
language : en
Publisher: Royal Society of Chemistry
Release Date : 2014-08-27
Principles And Practice Of Analytical Techniques In Geosciences written by Kliti Grice and has been published by Royal Society of Chemistry this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-08-27 with Science categories.
The pace of revolution in analytical chemistry in the field of Geosciences has been dramatic over recent decades and includes fundamental developments that have become common place in many related and unrelated disciplines. The analytical tools (nano to macro-scale from stable to radioactive isotopes, compound specific sulfur isotopes) used have been applied to wide-ranging applications from inorganic to organic geochemistry, biodiversity and chronological tools, to build an understanding of how the Earth system evolved to its present state. This book will provide an essential guide to exploring the earth’s natural resources and changing climate by detection science. Individual chapters bring together expertise from across the globe to present a comprehensive outlook on the analytical technologies available to the geoscientist today. Experienced researchers will appreciate the broad treatment of the subject as a valuable reference, while students and those new to the field will quickly gain an appreciation of both the techniques at hand, and the importance of constructing, and analysing, the complex data sets they can generate.
Development And Application Of Methods For Mass Spectrometry Imaging Of Lipids Across Biological Surfaces
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Author : Michael Edward Kurczy
language : en
Publisher:
Release Date : 2009
Development And Application Of Methods For Mass Spectrometry Imaging Of Lipids Across Biological Surfaces written by Michael Edward Kurczy and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Time of flight secondary ion mass spectrometric (ToF-SIMS) imaging is a powerful bioanalytical tool with the ability to produce molecular images of samples with submicron spatial resolution without the use of labels. In this thesis I will present the development of ToF-SIMS imaging methodology for biological analyses as well as applications that have yielded information about the role of lipids in membrane organization. In the first chapter, I introduce the plasma membrane and describe its fundamental role in maintaining life through the dynamic remodeling of its structure. I focus on two concepts that are believed to influence the localized chemical make up and structure of the membrane, intrinsic curvature and lipid domains. ToF-SIMS imaging is briefly described and a discussion of cluster ion bombardment and sample preparation is included. The chapter concludes with a survey of several important biological studies that have come out of the SIMS community. In Chapter 2 I report a protocol for the use of SIMS imaging to comparatively quantify the relative difference in cholesterol level between the plasma membranes of two cells. This development enables direct comparison of the chemical effects of different drug treatments and incubation conditions in the plasma membrane at the single-cell level. Relative, quantitative ToF-SIMS imaging was used to compare macrophage cells treated to contain elevated levels of cholesterol with respect to control cells. In-situ fluorescence microscopy with two different membrane dyes was used to discriminate morphologically similar but differentially treated cells prior to SIMS analysis. SIMS images of fluorescently identified cells reveal that the two populations of cells have distinct outer leaflet membrane compositions with the membranes of the cholesterol-treated macrophages containing more than twice the amount of cholesterol of control macrophages. Relative quantification with SIMS to compare the chemical composition of single-cells can provide valuable information about normal biological functions, causative agents of diseases, and possible therapies for diseases. Chapter 3 investigates prospects for three-dimensional SIMS analysis of biological materials using model multilayer structures and single cells. The samples were analyzed in a ToF-SIMS spectrometer equipped with a 20 and a 40 keV buckminsterfullerene (C60+) ion source. Specifically, molecular depth profile studies involving dehydrated dipalmitoylphosphatidylcholine (DPPC) organic films indicate that cell membrane lipid materials do not experience significant chemical damage when bombarded with C60+ ion fluences greater than 1015 ions/cm2. Moreover, depth profile analyses of DPPC?sucrose frozen multilayer structures suggest that biomolecule information can be uncovered after the C60+ sputter removal of a 20 nm overlayer with no appreciable loss of underlying molecular signal. The resulting depth information was used to characterize C60+ bombardment of biological materials. This information was used to controllably remove the plasma membrane of a single macrophage cell using a molecular depth profile approach allowing the analysis of the chemistry of the cytoplasm. Two methods that were developed to increase the reproducibility of biological SIMS analysis are covered in Chapter 4. First I demonstrate the utility of the C60+ cluster ion projectile for sputter cleaning biological surfaces to reveal obscured spatio-chemical information. Following the removal of nanometers of material from the surface using sputter cleaning; a frozen-patterned cholesterol film and a freeze-dried tissue sample were analyzed using ToF-SIMS imaging. In both experiments the chemical information was maintained after the sputter dose, due to the minimal chemical damage caused by C60+ bombardment. In fact, the damage to the surface produced by freeze-drying the tissue sample was found to have a greater effect on the loss of cholesterol signal than the sputter-induced damage. In addition to maintaining the chemical information, sputtering did not alter the spatial distribution of the surface chemistry. This approach removes artifacts that are common to many biological sample preparation schemes for ToF-SIMS imaging. Removing these artifacts, which may obscure the surface chemistry of the sample, will increase the number of analyzable samples for SIMS imaging. The second method covered in Chapter 4 is freeze-etching, the practice of removing excess surface water from a sample through sublimation into the vacuum of the analysis environment. This method was used to cryogenically preserve single cells for ToF-SIMS imaging analysis. By removing the excess water, which condenses onto the sample in vacuo, a uniform surface is produced that is ideal for imaging by static SIMS. I demonstrate that the conditions employed to remove deposited water do not adversely affect cell morphology and do not redistribute molecules in the top most surface layers. In addition, I found water could be controllably re-deposited onto the sample at temperatures below -100 oC in vacuum. The re-deposited water increases the ionization of characteristic fragments of biologically interesting molecules 2-fold without loss of spatial resolution. The utilization of freeze-etch methodology will increase the reliability of cryogenic sample preparations for SIMS analysis by providing greater control of the surface environment. Using these procedures we have obtained high quality images and spectra with both atomic bombardment as well as C60+ cluster ion bombardment. Sample handling is also the topic of Chapter 5. It this chapter, I describe a device which has been designed to prepare frozen, hydrated single cell cultures with a freeze fracture methodology for ToF-SIMS analysis in an ION-TOF (GmbH) TOF-SIMS IV mass spectrometer. The device reproducibly produces frozen hydrated sample surfaces for SIMS analysis. I show that SIMS analysis with the Bi32+ produces high-resolution molecular images of single PC12 cells in an ice matrix. I also show that the combination of ionization enhancements that are provided by both the ice matrix and the cluster ion source facilitates the localization of lipid ions that have not been localized in these cells previously. Namely, two fragments of phosphatidlyethanolamine (m/z 124 and m/z 142) and a large fragment of phosphatidylcholine (m/z 224). The ability to localize and measure these ions will increase the number of question that SIMS imaging can be used to answer. In Chapter 6 ToF-SIMS imaging was used to demonstrate that lipid domain formation in mating single-cell organisms is driven by changes in membrane structure. Studies of lipid bilayers in both living and model systems have revealed that lipid composition is coupled to localized membrane structure. However, it is still not clear if the lipids that compose the membrane actively modify membrane structure or if it is structural changes that cause lipid heterogeneity. I report that time of flight secondary ion mass spectrometry images of mating Tetrahymena thermophila acquired before, during and after mating demonstrate that lipid domain formation, identified as a decrease in the lamellar lipid phosphatidylcholine, does not precede structural changes in the membrane. Rather, domains are formed in response to function during cell-to-cell conjugation. ToF-SIMS imaging has been used to collect information with wide implications in all membrane processes. The work presented here is the continuation of a project aimed at chemically characterizing biological samples with spatially resolved mass spectra, with a particular focus on single cell imaging. Much of the work I have done has centered on understanding the capability of current technology and using this understanding to solve a particular problem. This work is vital to keeping SIMS in the biological realm but the development of new technology is the ultimate future for these experiments by increasing the number of tools that the experimenter has to choose from. In Chapter 7 discuss two ongoing projects that I think will lead to the next break through bringing us closer to realizing the goal of this project: a complete chemical map of a single cell.
Investigating Lipid Heterogeneity In Single Cells Using Time Of Flight Secondary Ion Mass Spectrometry
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Author : Paul D. Piehowski
language : en
Publisher:
Release Date : 2009
Investigating Lipid Heterogeneity In Single Cells Using Time Of Flight Secondary Ion Mass Spectrometry written by Paul D. Piehowski and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) can be utilized to map the spatial distribution of small molecules on a surface with potentially submicron resolution. Due to the inherent characteristics of this technique and its potential to provide higher spatial resolution than light microscopy based techniques without the use of chemical labels, it has been utilized to study the distribution of phospholipid species in the cell membrane. It is now known that many cell membranes contain transient compositional heterogeneities, colloquially referred to as domains, which participate in vital physiological processes such as exocytosis and signal transduction. Because of their size and lifetime, much remains unknown about the nature of these heterogeneities. ToF-SIMS imaging combined with cryogenic sample preparation techniques is a promising analytical platform poised to contribute greatly to this growing field of study. Sample preparation is crucial to obtaining quality lipid distribution maps, especially when dealing with single biological cells. To achieve this end the Winograd and Ewing groups have developed a freeze-fracture methodology adapted from cryo-SEM studies. Freeze-etching, the practice of removing excess surface water from a sample through sublimation into the vacuum of the analysis environment, has also been extensively used in conjunction with electron microscopy. This technique has been applied to ToF-SIMS imaging of cryogenically preserved single cells. By removing the excess water which condenses onto the sample in vacuo, a uniform surface is produced that is ideal for imaging by static SIMS. I demonstrate that the conditions employed to remove deposited water do not adversely affect cell morphology and do not redistribute molecules in the topmost surface layers. In addition, I found that water can be controllably re-deposited onto the sample at temperatures below -100° C in vacuum. The re-deposited water increases the ionization of characteristic fragments of biologically interesting molecules 2-fold without loss of spatial resolution. The utilization of freeze-etch methodology will increase the reliability of cryogenic sample preparations for SIMS analysis by providing greater control of the surface environment. Using these procedures, high quality spectra with both atomic bombardment as well as C60+ cluster ion bombardment, have been obtained. To date, many cell imaging studies have concentrated on phosphatidylcholine distributions, owing to its abundance and high ionization efficiency. However, cholesterol is a particularly interesting molecule due to its involvement in numerous biological processes. For many studies, the effectiveness of chemical mapping is limited by low signal intensity from various bio-molecules. Due to the high energy nature of the SIMS ionization process, many molecules are identified by detection of characteristic fragments. Commonly, fragments of a molecule are identified using standard samples, and those fragments are used to map the location of the molecule. MS/MS data obtained from a prototype C60+/ quadrupole time-of-flight mass spectrometer was used in conjunction with indium LMIG imaging to map previously unrecognized cholesterol fragments in single cells. A model system of J774 macrophages doped with cholesterol was used to show that these fragments are derived from cholesterol in cell imaging experiments. Examination of relative quantification experiments reveals that m/z 147 is the most specific diagnostic fragment and offers a 3-fold signal enhancement. These findings greatly increase the prospects for cholesterol mapping experiments in biological samples, particularly with single cell experiments. In addition, these findings demonstrate the wealth of information that is hidden in the traditional ToF-SIMS spectrum. In order for this technique to provide insight into biological processes, it is critical to characterize the figures of merit. Because a SIMS instrument counts individual events, the precision of the measurement is controlled by counting statistics. As the analysis area decreases, the number of molecules available for analysis diminishes. This becomes critical when imaging sub-cellular features; it limits the information obtainable, resulting in images with only a few counts of interest per pixel. Many features observed in low intensity images are artifacts of counting statistics, making validation of these features crucial to arriving at accurate conclusions. With ToF-SIMS imaging, the experimentally attainable spatial resolution is a function of the molecule of interest, sample matrix, concentration, primary ion, instrument transmission, and spot size of the primary ion beam. A model, based on Poisson statistics, has been developed to validate SIMS imaging data when signal is limited. This model can be used to estimate the effective spatial resolution and limits of detection prior to analysis, making it a powerful tool for tailoring future investigations. In addition, the model allows for pixel-to-pixel intensity comparisons and can be used to validate the significance of observed image features. The implications and capabilities of the model are demonstrated here by imaging the cell membrane of resting RBL-2H3 mast cells. Mass spectrometry imaging has been used to demonstrate that changes in membrane structure drive lipid domain formation in mating single-cell organisms. Chemical studies of lipid bilayers in both living and model systems have revealed that chemical composition is coupled to localized membrane structure. However, it is not clear if the lipids that compose the membrane actively modify membrane structure or if structural changes cause heterogeneity in the surface chemistry of the lipid bilayer. ToF-SIMS images of mating Tetrahymena thermophila, acquired at various stages during mating, can be used to demonstrate that lipid domain formation follows rather than precedes structural changes in the membrane. Domains are formed in response to structural changes that occur during cell-to-cell conjugation. This observation has wide implications in all membrane processes. There is considerable interest in the unique properties of cluster ion projectiles and investigations of how they may be utilized to improve biological imaging. A C60+ cluster ion projectile was employed for sputter cleaning biological surfaces to reveal spatio-chemical information obscured by contamination overlayers. This protocol is used as a supplemental sample preparation method for time of flight secondary ion mass spectrometry (ToF-SIMS) imaging of frozen and freeze dried biological materials. Following the removal of nanometers of material from the surface using sputter cleaning; a frozen-patterned cholesterol film and a freeze-dried tissue sample were analyzed using ToF-SIMS imaging. In both experiments, the chemical information was maintained after the sputter dose, due to the minimal chemical damage caused by C60+ bombardment. The damage to the surface produced by freeze-drying the tissue sample was found to have a greater effect on the loss of cholesterol signal than the sputter-induced damage. In addition to maintaining the chemical information, sputtering is not found to alter the spatial distribution of molecules on the surface. This approach removes artifacts that may obscure the surface chemistry of the sample and are common to many biological sample preparation schemes for ToF-SIMS imaging. In general, out results show that by removing these artifacts, the number of analyzable samples for SIMS imaging is greatly expanded. Although imaging with sub-cellular spatial resolution has been demonstrated, it is clear that the success of future experiments is limited by the ionization efficiency of the lipids, as well as limitations imposed by a coaxial ToF geometry. Considerable work has been done in the lab, to address these limitations. This effort has resulted in the development of a hybrid quadrupole orthogonal ToF instrument equipped with a C60+ primary ion source. The capabilities and potential of this new platform will greatly increase the contributions of SIMS to the biological sciences.
Practice Of Intramedullary Locked Nails
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Author : Volker Alt
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-03-04
Practice Of Intramedullary Locked Nails written by Volker Alt and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-03-04 with Medical categories.
The third volume of the "Practice of Intramedullary Locked Nails" places a special focus on recent advancements in understanding the biology of fracture healing of long bones, the emerging technologies that further enhance the minimally invasive nature of closed treatment of fractures, and the availability of various surgical techniques in intramedullary fixation. The application of new technology in prevention of infection and application of the intramedullary fixation of fractures in pediatric and adolescent patients are also described. The contributors to this volume are from different well-known trauma centers and are pioneer surgeons in the development and practice of intramedullary locked nails.
Metal Forming Science And Practice
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Author : J.G. Lenard
language : en
Publisher: Elsevier
Release Date : 2002-10-08
Metal Forming Science And Practice written by J.G. Lenard and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002-10-08 with Science categories.
This publication has been written to honour the contribution to science and education made by the Distinguished Professor Emeritus Professor Schey on his eightieth birthday. The contributors to his book are among the countless researchers who have read, studied and learned from Professor Schey's work, which includes books, research monographs, invited papers, keynote papers, scientific journals and conferences. The topics include manufacturing, sheet and bulk metal forming and tribology, amongst others. The topics included in this book include: John Schey and value-added manufacturing; Surface finish and friction in cold-metal rolling; Direct observation of interface for tribology in metal forming; An examination of the coefficient of friction; Studies on micro plasto hydrodynamic lubrication in metal forming; Numerical simulation of sheet metal forming; Geometric and mechanics model of sheet forming; Modelling and optimisation of metal forming processes; The mathematical modelling of hot rolling steel; Identification of rheological and tribological parameters; Oxide behaviour in hot rolling; Friction, lubrication and surface response in wire drawing; and Modelling and control of temper rolling and skin pass rolling.
Time Of Flight Secondary Ion Mass Spectrometry
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Author : Joanna Lee
language : en
Publisher:
Release Date : 2011
Time Of Flight Secondary Ion Mass Spectrometry written by Joanna Lee and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful technique for the analysis of organic surfaces and interfaces for many innovative technologies. However, despite recent developments, there are still many issues and challenges hindering the robust, validated use of ToF-SIMS for quantitative measurement. These include: the lack of metrology and fundamental understanding for the use of novel cluster primary ion beams such as C60n+ and Ar2000 +; the need for validated and robust measurement protocols for difficult samples, such as those with significant micron scale surface topography; the lack of guidance on novel data analysis methods including multivariate analysis which have the potential to simplify many time-consuming and intensive analyses in industry; and the need to establish best practice to improve the accuracy of measurements. This thesis describes research undertaken to address the above challenges. Sample topography and field effects were evaluated experimentally using model conducting and insulating fibres and compared with computer simulations to provide recommendation to diagnose and reduce the effects. Two popular multivariate methods, principal component analysis (PCA) and multivariate curve resolution (MCR), were explored using mixed organic systems consisting of a simple polymer blend and complex hair fibres treated with a multi-component formulation to evaluate different multivariate and data preprocessing methods for the optimal identification, localisation and quantification of the chemical components. Finally, cluster ion beams C60 n+ and ArSOO-2S00 + were evaluated on an inorganic surface and an organic delta layer reference material respectively to elucidate the fundamental metrology of cluster ion sputtering and pave the way for their use in organic depth profiling. These studies provide the essential metrological foundation to address frontier issues in surface and nanoanalysis and extend the measurement capabilities ofToF-SIMS.
Plastics Additives
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Author : Jan C. J. Bart
language : en
Publisher: IOS Press
Release Date : 2006
Plastics Additives written by Jan C. J. Bart and has been published by IOS Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Technology & Engineering categories.
Contains an outline of the principles and characteristics of relevant instrumental techniques, provides an overview of various aspects of direct additive analysis by focusing on an array of applications in R ampD, production, quality control, and technical service.
Wills Mineral Processing Technology
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Author : Barry A. Wills
language : en
Publisher: Butterworth-Heinemann
Release Date : 2015-09-01
Wills Mineral Processing Technology written by Barry A. Wills and has been published by Butterworth-Heinemann this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-09-01 with Technology & Engineering categories.
Wills' Mineral Processing Technology: An Introduction to the Practical Aspects of Ore Treatment and Mineral Recovery has been the definitive reference for the mineral processing industry for over thirty years. This industry standard reference provides practicing engineers and students of mineral processing, metallurgy, and mining with practical information on all the common techniques used in modern processing installations. Each chapter is dedicated to a major processing procedure—from underlying principles and technologies to the latest developments in strategies and equipment for processing increasingly complex refractory ores. The eighth edition of this classic reference enhances coverage of practical applications via the inclusion of new material focused on meeting the pressing demand for ever greater operational efficiency, while addressing the pivotal challenges of waste disposal and environmental remediation. Advances in automated mineralogy and analysis and high-pressure grinding rolls are given dedicated coverage. The new edition also contains more detailed discussions of comminution efficiency, classification, modeling, flocculation, reagents, liquid-solid separations, and beneficiation of phosphate, and industrial materials. Finally, the addition of new examples and solved problems further facilitates the book’s pedagogical role in the classroom. Connects fundamentals with practical applications to benefit students and practitioners alike Ensures relevance internationally with new material and updates from renowned authorities in the UK, Australia, and Canada Introduces the latest technologies and incorporates environmental issues to place the subject of mineral processing in a contemporary context, addressing concerns of sustainability and cost effectiveness Provides new case studies, examples, and figures to bring a fresh perspective to the field
Tof Sims
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Author : John C. Vickerman
language : en
Publisher:
Release Date : 2001
Tof Sims written by John C. Vickerman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with Mass spectrometry categories.
Time-of-flight secondary ion mass spectroemtry is the most versatile of surface analysis techniques that has been developed. Following an overview, this work includes sections devoted to: instrumentation and sample handling; fundamentals and molecular dynamics simulations; optimisation methods; and data interpretation, and analytical applications.