Investigating Cellular Nanoscale with X-rays

Investigating Cellular Nanoscale with X-rays
Title Investigating Cellular Nanoscale with X-rays PDF eBook
Author Clément Hémonnot
Publisher Göttingen University Press
Pages 192
Release 2016
Genre
ISBN 3863952871

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The advances and technical improvements of X-ray imaging techniques, taking advantage of X-ray focussing optics and high intensity synchrotron sources, nowadays allow for the use of X-rays to probe the cellular nanoscale. Importantly, X-rays permit thick samples to be imaged without sectioning or slicing. In this work, two macromolecules, namely keratin intermediate filament (IF) proteins and DNA, both essential components of cells, were studied by X-ray techniques. Keratin IF proteins make up an integral part of the cytoskeleton of epithelial cells and form a dense intracellular network of bundles. This network is built from monomers in a hierarchical fashion. Thus, the keratin structure formation spans a large range of length scales from a few nanometres (monomers) to micrometres (networks). Here, keratin was studied at three different scales: i) filaments, ii) bundles and iii) networks. Solution small-angle X-ray scattering revealed distinct structural and organisational characteristics of these highly charged polyelectrolyte filaments, such as increasing radius with increasing salt concentration and spatial accumulation of ions depending on the salt concentration. The results are quantified by employing advanced modelling of keratin IFs by a core cylinder fl anked with Gaussian chains. Scanning micro- diffraction was used to study keratin at the bundle scale. Very different morphologies of keratin bundles were observed at different salt conditions. At the network scale, new imaging approaches and analyses were applied to the study of whole cells. Ptychography and scanning X-ray nano-diffraction imaging were performed on the same cells, allowing for high resolution in real and reciprocal space, thereby revealing the internal structure of these networks. By using a fitting routine based on simulations of IFs packed on a hexagonal lattice, the radius of each fi lament and distance between fi laments were retrieved. In mammalian cells, each nucleus contains 2 nm-thick DNA double helices with a total length of about 2 m. The DNA strands are packed in a highly hierarchical manner into individual chromosomes. DNA was studied in intact cells by visible light microscopy and scanning X-ray nano-diffraction, unveiling the compaction und decompaction of DNA during the cell cycle. Thus, we obtained information on the aggregation state of the nuclear DNA at a real space resolution on the order of few hundreds nm. To exploit to the reciprocal space information, individual diffraction patterns were analysed according to a generalised Porod’s law at a resolution down to 10 nm. We were able to distinguish nucleoli, heterochromatin and euchromatin in the nuclei and follow the compaction and decompaction during the cell division cycle.

Nanoscale Photonic Imaging

Nanoscale Photonic Imaging
Title Nanoscale Photonic Imaging PDF eBook
Author Tim Salditt
Publisher Springer Nature
Pages 634
Release 2020-06-09
Genre Science
ISBN 3030344134

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This open access book, edited and authored by a team of world-leading researchers, provides a broad overview of advanced photonic methods for nanoscale visualization, as well as describing a range of fascinating in-depth studies. Introductory chapters cover the most relevant physics and basic methods that young researchers need to master in order to work effectively in the field of nanoscale photonic imaging, from physical first principles, to instrumentation, to mathematical foundations of imaging and data analysis. Subsequent chapters demonstrate how these cutting edge methods are applied to a variety of systems, including complex fluids and biomolecular systems, for visualizing their structure and dynamics, in space and on timescales extending over many orders of magnitude down to the femtosecond range. Progress in nanoscale photonic imaging in Göttingen has been the sum total of more than a decade of work by a wide range of scientists and mathematicians across disciplines, working together in a vibrant collaboration of a kind rarely matched. This volume presents the highlights of their research achievements and serves as a record of the unique and remarkable constellation of contributors, as well as looking ahead at the future prospects in this field. It will serve not only as a useful reference for experienced researchers but also as a valuable point of entry for newcomers.

Investigations on Joule heating applications by multiphysical continuum simulations in nanoscale systems

Investigations on Joule heating applications by multiphysical continuum simulations in nanoscale systems
Title Investigations on Joule heating applications by multiphysical continuum simulations in nanoscale systems PDF eBook
Author Feuchter, Manuel Klaus Ludwig
Publisher KIT Scientific Publishing
Pages 258
Release 2014-10-01
Genre Technology & Engineering
ISBN 3731502615

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This work furthers the overall understanding of a 3w-measurement, by considering previously unexamined macroscopic influence factors within measurement by Finite Element simulations (FES). Moreover, new measuring configurations are developed to determine (an)isotropic thermal conductivities of nanoscale samples. Since no analytic solutions are available for these configurations, a new evaluation methodology is presented to determine emergent thermal conductivities by FES and Neural Networks.

Unraveling the Safety Profile of Nanoscale Particles and Materials

Unraveling the Safety Profile of Nanoscale Particles and Materials
Title Unraveling the Safety Profile of Nanoscale Particles and Materials PDF eBook
Author Andreia Ferreira de Castro Gomes
Publisher BoD – Books on Demand
Pages 174
Release 2018-03-21
Genre Technology & Engineering
ISBN 9535139398

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As nanomaterials become increasingly present in our daily lives, pertinent questions regarding their safety arise. Nanomaterial risk assessment, as in other areas, directs much of the effort worldwide in defining guidelines that may be translated into national or international directives. Nanomaterials encompass different entities, from nanoparticles to nanostructured materials, with specific effects over cells, tissues, organisms and ecosystems depending on their biophysical characteristics. Such interactions will directly affect the impact of novel nanotechnologies. This book aims to provide the reader with a comprehensive overview of the current state of the art in nanotoxicology, featuring the most important developments and critical issues regarding the use of and exposure to nanoparticles.

Synchrotron Radiation in Materials Science

Synchrotron Radiation in Materials Science
Title Synchrotron Radiation in Materials Science PDF eBook
Author Chunhai Fan
Publisher John Wiley & Sons
Pages 846
Release 2018-05-29
Genre Technology & Engineering
ISBN 3527339868

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Meeting the long-felt need for in-depth information on one of the most advanced material characterization methods, a top team of editors and authors from highly prestigious facilities and institutions covers a range of synchrotron techniques that have proven useful for materials research. Following an introduction to synchrotron radiation and its sources, the second part goes on to describe the various techniques that benefit from this especially bright light, including X-ray absorption, diffraction, scattering, imaging, and lithography. The thrid and final part provides an overview of the applications of synchrotron radiation in materials science. bridging the gap between specialists in synchrotron research and material scientists, this is a unique and indispensable resource for academic and industrial researchers alike.

Metal-based Anticancer Agents

Metal-based Anticancer Agents
Title Metal-based Anticancer Agents PDF eBook
Author Angela Casini
Publisher Royal Society of Chemistry
Pages 370
Release 2019-04-05
Genre Science
ISBN 1788017676

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Metal-based anticancer drugs are among the most successful therapeutic agents, as evidenced by the frequent prescription of selected platinum and arsenic compounds to patients. Metal-based Anticancer Agents covers the interdisciplinary world of inorganic drug discovery and development by introducing the most prominent compound classes based on different transition metals, discussing emerging concepts and enabling methods, as well as presenting key pre-clinical and clinical aspects. Recent progress on the unique features of next-generation targeted metal-based anticancer agents, including supramolecular coordination complexes used for both therapy and drug delivery, promise a bright future beyond the benefits of pure cytotoxic activity. With contributions from global leaders in the field, this book will serve as a useful reference to established researchers as well as a practical guide to those new to metallodrugs, and postgraduate students of medicinal chemistry and metallobiology.

Small Angle Scattering and Diffraction

Small Angle Scattering and Diffraction
Title Small Angle Scattering and Diffraction PDF eBook
Author Margareth Kazuyo Kobayashi Dias Franco
Publisher BoD – Books on Demand
Pages 118
Release 2018-06-06
Genre Science
ISBN 1789232465

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Reasoned and based on the difference between discovery and invention, according to the traditional conception, science can be distinguished between basic science and applied science. Nevertheless, we know that the sciences are inseparable. A century or more ago, Louis Pasteur said "there is no applied science, there are applications of science." With this assertion, he establishes the logic of complementarity between them. Science certainly goes beyond its own material application and brings us to issues that have intrigued humanity for a long time. During the many years that we have been working with techniques of material characterization, we observed that this complementarity was not always understood by the researchers. In line with the reasoning that the technique joined with science generates technology, the application of techniques that use x-ray and neutron sources seems to us of fundamental importance for the development of technology. In this way, we present in this book how the existing technology of material characterization can contribute to science and applied technology. The authors who contributed with this book sought to show the importance of applying the existing techniques in the development of their works.