Visualizing Chemistry The Progress and Promise of Advanced Chemical Imaging (2006) / Chapter Skim
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4 Committee Findings and Recommendations
4 Committee Findings and Recommendations
Pages 179-198
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From page 179... ...
Concurrently, advances in other areas of research -- such as nanoscience and materials -- underlie the developments needed to push chemical imaging ahead even further. Chemical imaging techniques span a broad array of capabilities and applications.
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From page 180... ...
or scanning electron microscopy (SEM) combined with X-ray photoemission spectroscopy (XPS)
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From page 181... ...
The main findings of the committee are: Nuclear Magnetic Resonance Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI)
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From page 182... ...
Exciting developments for hyperpolarization using a variety of techniques -- such as dynamic nuclear polarization, laser-induced hyperpolarization of noble gases, and formation of parahydrogen -- have realized extraordinary gains in sensitivity for applications to materials research and biomedical imaging. At present only a restricted set of molecules has been hyperpolarized using only a small set of possible techniques.
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From page 183... ...
Most of this has been proof-of-principle work; the more difficult task of optimizing these approaches to ensure their robustness must now be undertaken. Finally, preliminary work in identifying MRI-active proteins or protein assemblies that are equivalent to fluorescent proteins has begun.
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Metallic nanoparticles have long been used in Mie scattering darkfield microscopy. However, nonspherical particles and their aggregates, which cannot be described by classic Mie scattering theory, offer rich optical properties associated with surface plasma-related phenomena.
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From page 185... ...
For example, green fluorescent protein and its derivatives allow live cell imaging and tracking of individual proteins. In addition, techniques such as fluorescence correlation spectroscopy (FCS)
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From page 186... ...
Continued developments in these nonlinear approaches will enable superhigh resolution using far-field optics without the need to employ proximal probes. Multiphoton fluorescence microscopy can also benefit from the development of more compact ultrafast lasers, fiber delivery, and improved fluorophores with larger nonlinear polarizability.
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From page 187... ...
Higher sensitivity detectors will reduce the amount of electrons needed to image, therefore minimizing the damage that may occur from the electron beam. This will greatly expand the in situ environments for EM that are vital for imaging chemistry, such as reaction dynamics and electron-sensitive materials, including organics and biological samples.
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From page 188... ...
For trace element mapping in microprobes or mapping nanoscale chemical heterogeneities in spectromicroscopy, higher spatial resolution translates into the ability to carry out chemical imaging at a finer scale with less biasing of quantification. In addition, for immunolabeling, the label size must be comparable to the zone plate resolution in order to be detected; the development of higher-resolution optics will allow the use of smaller labels, which are dramatically easier to coax across the membrane of a cell.
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From page 189... ...
Furthermore, based on the X-ray absorption coefficient, all measurements can be quantified in terms of concentration as well as location. On the other hand, the detection of specific chemical signals from exogenous molecules in the cell requires the development of probes analogous to green fluorescent protein (GFP)
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For example, the development of proximal probe methods (e.g., magnetic resonance force microscopy) by which images of samples can be recorded with high spatial resolution in all three dimensions would represent a major breakthrough in chemical imaging technology.
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of controlled geometry near-field optics. Image Processing and Analysis Chemical imaging is used to selectively detect, analyze, and identify chemical and biological samples, followed by visualization of the data in the dimension of interest.
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Chemical imaging can benefit from other fields that depend on image analysis. The remote sensing field is rich in techniques for image analysis that are largely unexploited in chemical imaging; some kind of cross-fertilization between these two communities should be promoted.
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Electronic Structure and Molecular Dynamics Simulations A quantitative understanding of the electronic structure of molecules and the theory that predicts the outcome of interactions of molecules with electromagnetic fields will aid in the development of chemical imaging probes for all imaging modalities. For example, it has been known since the first NMR experiments that chemical shifts are exquisitely sensitive to the electronic environment of a molecule.
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From page 194... ...
However, further development of terahertz spectroscopy as a powerful tool for imaging will depend on the development of convenient new terahertz light sources. Brighter, tunable ultrafast light sources need to be developed, particularly infrared-terahertz vibrational and dynamic imaging, near-field scanning optical microscopy (NSOM)
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There is a need to develop optics for miniaturization and speeding of microscopic imaging instrumentation in order to improve chemical imaging capabilities. Acquisition Speed and Efficiency Higher-speed scanning probes that now reach video-rate imaging have been developed.
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Funding In many aspects, the resource appropriation for chemical imaging research works quite well. For example, support for synchrotron light sources is very effective and should be continued.
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Standards are needed for chemical imaging that allows image data to be effectively catalogued and shared between large numbers of researchers. These data should be organized in visually oriented, searchable, and parameterized databases, with common platforms for a vast array of image types.
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198 VISUALIZING CHEMISTRY NOTES 1. Kneipp K., H
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