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Function Relations (function + relation)
Selected AbstractsSpoken Language Pragmatics: An Analysis of Form,Function Relations,edited by WEINERT, REGINAMODERN LANGUAGE JOURNAL, Issue 2 2010CARMEN TALEGHANI, NIKAZM No abstract is available for this article. [source] Molecular Structure,Function Relations of the Optical Properties and Dimensions of Gold Nanoparticle Assemblies,ANGEWANDTE CHEMIE, Issue 7 2010Revital Kaminker Geometrische Vorgaben: Die Form einer Reihe von molekularen Vernetzern, die eine bis vier Pyridyleinheiten tragen, bestimmt die optischen Eigenschaften von Aggregaten aus Goldnanopartikeln (AuNPs; siehe Bild). Wie eine TEM-Analyse belegt, übertragen sich die unterschiedlichen Molekülstrukturen bei der Aggregation der AuNPs auf die Submikrometerebene. [source] Influence of Structural Principles on the Mechanics of a Biological Fiber-Based Composite Material with Hierarchical Organization: The Exoskeleton of the Lobster Homarus americanusADVANCED MATERIALS, Issue 4 2009Helge-Otto Fabritius Abstract The cuticle of the lobster Homarus americanus is a nanocomposite, such as most structural biological materials. It consists of a matrix of chitin-protein fibers associated with various amounts of crystalline and amorphous calcium carbonate in the rigid parts of the body, and is organized hierarchically at all length scales. One prominent design principle found in the hierarchical structure of such biological fibrous composite materials is the twisted plywood structure. In the lobster cuticle, it is formed by superimposing and gradually rotating planes of parallel aligned chitin-protein fibers. To adjust the mechanical properties to the requirements on the macroscopic level, the spatial arrangement and the grade of mineralization of the fibers can be modified. A second design principle of lobster cuticle is its honeycomb-like structure, generated by the well-developed pore canal system, whose twisted ribbon-shaped canals penetrate the cuticle perpendicular to its surface. Due to the hierarchical structure, the mechanical properties of the lobster cuticle have to be investigated at different length scales, which is essential for the understanding of the structure,mechanical function relations of mineralized tissues (e.g., potentially also bone and teeth). In order to investigate the influence of the structural principles on the mechanical properties on the macroscopic scale miniaturized tensile, compression, and shear tests were carried out to obtain integral mechanical data. Characterization of the microstructure included scanning electron microscopy (SEM) combined with energy dispersive X-ray (EDX) measurements. [source] Applications of ACORN to data at 1.45 Å resolutionJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2004V. Rajakannan One of the main interests in the molecular biosciences is in understanding structure,function relations and X-ray crystallography plays a major role in this. ACORN can be used as a comprehensive and efficient phasing procedure for the determination of protein structures when atomic resolution data are available. An initial model can automatically be built by ARP/wARP followed by REFMAC for refinement. The , helices and , sheets occurring in many protein structures can be taken as starting fragments for structure solution in ACORN. ACORN, along with ARP/wARP followed by REFMAC, can be an ab initio method for solving protein structure for which data are better than 1.2 Å (atomic resolution). Attempts are here made in extending its applications to real data at 1.45 Å resolution and also to truncated data at 1.6 Å resolution. Two previously known structures, congerin II and alkaline cellulase N257, were resolved using the above approach. Automatic structure solution, phasing and refinement for real data at still lower resolutions for proteins of various complexities are being carried out. Data mining of the secondary structural features using PDB is being carried out for this new approach for `seed-phasing' to ACORN. [source] X-ray absorption spectroscopy to watch catalysis by metalloenzymes: status and perspectives discussed for the water-splitting manganese complex of photosynthesisJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2003Holger Dau Understanding structure,function relations is one of the main interests in the molecular biosciences. X-ray absorption spectroscopy of biological samples (BioXAS) has gained the status of a useful tool for characterization of the structure of protein-bound metal centers with respect to the electronic structure (oxidation states, orbital occupancies) and atomic structure (arrangement of ligand atoms). Owing to progress in the performance characteristics of synchrotron radiation sources and of experimental stations dedicated to the study of (ultra-dilute) biological samples, it is now possible to carry out new types of BioXAS experiments, which have been impracticable in the past. Of particular interest are approaches to follow biological catalysis at metal sites by characterization of functionally relevant structural changes. In this article, the first steps towards the use of BioXAS to `watch' biological catalysis are reviewed for the water-splitting reactions occurring at the manganese complex of photosynthesis. The following aspects are considered: the role of BioXAS in life sciences; methodological aspects of BioXAS; catalysis at the Mn complex of photosynthesis; combination of EXAFS and crystallographic information; the freeze-quench technique to capture semi-stable states; time-resolved BioXAS using a freeze-quench approach; room-temperature experiments and `real-time' BioXAS; tasks and perspectives. [source] | ||||||||||