Protein Conformational Dynamics


Book Description

This book discusses how biological molecules exert their function and regulate biological processes, with a clear focus on how conformational dynamics of proteins are critical in this respect. In the last decade, the advancements in computational biology, nuclear magnetic resonance including paramagnetic relaxation enhancement, and fluorescence-based ensemble/single-molecule techniques have shown that biological molecules (proteins, DNAs and RNAs) fluctuate under equilibrium conditions. The conformational and energetic spaces that these fluctuations explore likely contain active conformations that are critical for their function. More interestingly, these fluctuations can respond actively to external cues, which introduces layers of tight regulation on the biological processes that they dictate. A growing number of studies have suggested that conformational dynamics of proteins govern their role in regulating biological functions, examples of this regulation can be found in signal transduction, molecular recognition, apoptosis, protein / ion / other molecules translocation and gene expression. On the experimental side, the technical advances have offered deep insights into the conformational motions of a number of proteins. These studies greatly enrich our knowledge of the interplay between structure and function. On the theoretical side, novel approaches and detailed computational simulations have provided powerful tools in the study of enzyme catalysis, protein / drug design, protein / ion / other molecule translocation and protein folding/aggregation, to name but a few. This work contains detailed information, not only on the conformational motions of biological systems, but also on the potential governing forces of conformational dynamics (transient interactions, chemical and physical origins, thermodynamic properties). New developments in computational simulations will greatly enhance our understanding of how these molecules function in various biological events.




Synchrotron Light Sources and Free-Electron Lasers


Book Description

Hardly any other discovery of the nineteenth century did have such an impact on science and technology as Wilhelm Conrad Röntgen’s seminal find of the X-rays. X-ray tubes soon made their way as excellent instruments for numerous applications in medicine, biology, materials science and testing, chemistry and public security. Developing new radiation sources with higher brilliance and much extended spectral range resulted in stunning developments like the electron synchrotron and electron storage ring and the freeelectron laser. This handbook highlights these developments in fifty chapters. The reader is given not only an inside view of exciting science areas but also of design concepts for the most advanced light sources. The theory of synchrotron radiation and of the freeelectron laser, design examples and the technology basis are presented. The handbook presents advanced concepts like seeding and harmonic generation, the booming field of Terahertz radiation sources and upcoming brilliant light sources driven by laser-plasma accelerators. The applications of the most advanced light sources and the advent of nanobeams and fully coherent x-rays allow experiments from which scientists in the past could not even dream. Examples are the diffraction with nanometer resolution, imaging with a full 3D reconstruction of the object from a diffraction pattern, measuring the disorder in liquids with high spatial and temporal resolution. The 20th century was dedicated to the development and improvement of synchrotron light sources with an ever ongoing increase of brilliance. With ultrahigh brilliance sources, the 21st century will be the century of x-ray lasers and their applications. Thus, we are already close to the dream of condensed matter and biophysics: imaging single (macro)molecules and measuring their dynamics on the femtosecond timescale to produce movies with atomic resolution.




Giant Resonances in Atoms, Molecules, and Solids


Book Description

Often, a new area of science grows at the confines between recognised subject divisions, drawing upon techniques and intellectual perspectives from a diversity of fields. Such growth can remain unnoticed at first, until a characteristic fami ly of effects, described by appropriate key words, has developed, at which point a distinct subject is born. Such is very much the case with atomic 'giant resonances'. For a start, their name itself was borrowed from the field of nuclear collective resonances. The energy range in which they occur, at the juncture of the extreme UV and the soft X-rays, remains to this day a meeting point of two different experimental techniques: the grating and the crystal spectrometer. The impetus of synchrotron spectroscopy also played a large part in developing novel methods, described by many acronyms, which are used to study 'giant resonances' today. Finally, although we have described them as 'atomic' to differentiate them from their counterparts in Nuclear Physics, their occurrence on atomic sites does not inhibit their existence in molecules and solids. In fact, 'giant resonances' provide a new unifying theme, cutting accross some of the traditional scientific boundaries. After much separate development, the spectroscopies of the atom in various environments can meet afresh around this theme of common interest. Centrifugal barrier effects and 'giant resonances' proper emerged almost simultaneously in the late 1960's from two widely separated areas of physics, namely the study of free atoms and of condensed matter.




Physics Division Annual Report


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Government Reports Index


Book Description




Organic Reaction Mechanisms 1970


Book Description

The only book series to summarize the latest progress on organic reaction mechanisms, Organic Reaction Mechanisms, 1970 surveys the development in understanding of the main classes of organic reaction mechanisms reported in the primary scientific literature in 1970. The 6th annual volume in this highly successful series highlights mechanisms of stereo-specific reactions. Reviews are compiled by a team of experienced editors and authors, allowing advanced undergraduates, graduate students, postdocs, and chemists to rely on the volume's continuing quality of selection and presentation.




Light Exotic Nuclei Near The Boundary Of Neutron Stability


Book Description

The monograph describes the properties of the lightest nuclei with large excess of neutrons. The results of theoretical and experimental studies of neutron-rich isotopes with 1 ≤ Z ≤ 20 are presented while also changes in the structure of nuclei when going away from the line of β-stability are discussed. Information presented is on the mass, radii of distribution of nuclear matter, energy levels for excited states of these nuclei, the possibility of manifestation of a halo, as well as the deformation of nuclei and the quantum properties of ground states. The position of the boundary of nucleon stability for these nuclei is considered. The effects associated with weakening and even the disappearing influence of standard magic numbers and the appearance of new ones are discussed.The results presented in the book will be useful in other fields of science as well, including astrophysics.