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61.
Site‐Selective Disulfide Modification of Proteins: Expanding Diversity beyond the Proteome 下载免费PDF全文
Dr. Seah Ling Kuan Dr. Tao Wang Prof. Dr. Tanja Weil 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17112-17129
The synthetic transformation of polypeptides with molecular accuracy holds great promise for providing functional and structural diversity beyond the proteome. Consequently, the last decade has seen an exponential growth of site‐directed chemistry to install additional features into peptides and proteins even inside living cells. The disulfide rebridging strategy has emerged as a powerful tool for site‐selective modifications since most proteins contain disulfide bonds. In this Review, we present the chemical design, advantages and limitations of the disulfide rebridging reagents, while summarizing their relevance for synthetic customization of functional protein bioconjugates, as well as the resultant impact and advancement for biomedical applications. 相似文献
62.
Tanja Zseby Joachim Fabini Dipika Rani 《e & i Elektrotechnik und Informationstechnik》2014,131(1):8-13
Synchronized phasor measurements provide the basis for fine-grained wide area power quality monitoring in electric grids. Time-synchronized phasor measurement units (PMUs) are deployed at different locations in the grid and report 10–60 measurements/second to energy management systems or other applications. For control applications it is crucial to receive measurement data as soon as possible after a state change in order to trigger corrective actions in time to prevent incidents in the grid. In this paper we analyze characteristics of synchrophasor M2M communication for different network technologies, including VDSL, HSPA and LTE networks. We briefly review synchrophasor communication approaches and real-time demands. We then emulate PMU traffic and perform measurements on different networks. We show how the underlying technology influences one-way delay patterns for synchrophasor communication, which has direct implication on the achievable real-time properties. 相似文献
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Tanja Seraidaris Arto Puranen Mikko Karesoja Barbro Lfgren Timo Repo Markku Leskel Jukka Seppl 《Journal of polymer science. Part A, Polymer chemistry》2006,44(16):4743-4751
Elastic polypropene has gained growing industrial and academic interest as a thermoplastic elastomer. In this study, “rac”‐ and “meso”‐dimethylsilyl(3‐benzylindenyl)(2‐methylindenyl)hafnium dichloride complexes (Hfr and Hfm, respectively), activated with [NHMe2Ph][B(C6F5)4]/triisobutyl aluminum, were used in propene polymerization. Using these catalyst systems, we obtained polymers with high molar masses, up to 550 kg/mol, and moderate isotacticities between 34 and 52%. By varying the polymerization conditions, we could modify the polymer microstructure and molar mass. 13C NMR was used to calculate the polymer pentad sequence distributions. The crystalline parts of the polymers were analyzed with the differential scanning calorimetry successive self‐nucleation and annealing (SSA) technique. The SSA thermograms revealed that Hfr produced polypropene with a more uniform lamellar structure than Hfm. The mechanical properties were tested with dynamic mechanical analysis creep‐recovery tests. In the series, the polymers with the lowest isotacticities and therefore lowest crystallinities showed the best elastic properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4743–4751, 2006 相似文献
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Synthesis of Cembranoid Analogues through Ring‐Closing Metathesis of Terpenoid Precursors: A Challenge Regarding Ring‐Size Selectivity 下载免费PDF全文
Tanja Heidt Dr. Angelika Baro Prof. Andreas Köhn Prof. Sabine Laschat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(35):12396-12404
A systematic study on ring‐closing metathesis with Grubbs II catalyst to cembranoid macrocycles is described. Acyclic terpenoids with a functional group X in the homoallylic position relative to an RCM active terminus and substituents R, R1 directly attached to the other terminal double bond were prepared from geraniol derived trienes and fragments that are based on bromoalkenes and dimethyl malonate. Such terpenoids were suitable precursors, despite the presence of competing double bonds in their framework. The size of R and R1 is crucial for successful macrocyclization. Whereas small alkyl substituents at the double bond directed the RCM towards six‐membered ring formation, cross metathesis leading to dimers dominated for bulkier alkyl groups. A similar result was obtained for precursors without functional group X. In the case of unsymmetrically substituted terpenoid precursor (R=Et, R1=Me) with homoallylic OTBS or OMe group, the RCM could be controlled towards formation of macrocyclic cembranoids, which were isolated with excellent E‐selectivity. The role of the substituents was further studied by quantum chemical calculations of simplified model substrates. Based on these results a mechanistic rationale is proposed. 相似文献
68.
Toll convexity is a variation of the so-called interval convexity. A tolled walk between two non-adjacent vertices and in a graph is a walk, in which is adjacent only to the second vertex of and is adjacent only to the second-to-last vertex of . A toll interval between is a set . A set is toll convex, if for all . A toll closure of a set is the union of toll intervals between all pairs of vertices from . The size of a smallest set whose toll closure is the whole vertex set is called a toll number of a graph , . The first part of the paper reinvestigates the characterization of convex sets in the Cartesian product of two graphs. It is proved that the toll number of the Cartesian product of two graphs equals 2. In the second part, the toll number of the lexicographic product of two graphs is studied. It is shown that if is not isomorphic to a complete graph, . We give some necessary and sufficient conditions for . Moreover, if has at least two extreme vertices, a complete characterization is given. Furthermore, graphs with are characterized. Finally, the formula for is given — it is described in terms of the so-called toll-dominating triples or, if is complete, toll-dominating pairs. 相似文献
69.
In this tutorial review the basic approaches to establish electrochemical communication between redox-active proteins and electrodes are elucidated and examples for applications in electrochemical biosensors, biofuel cells and nanotechnology are presented. The early stage of protein electrochemistry is described giving a short overview over electron transfer (ET) between electrodes and proteins, followed by a brief introduction into experimental procedures for studying proteins at electrodes and possible applications arising thereof. The article starts with discussing the electrochemistry of cytochrome c, the first redox-active protein, for which direct reversible ET was obtained, under diffusion controlled conditions and after adsorption to electrodes. Next, examples for the electrochemical study of redox enzymes adsorbed on electrodes and modes of immobilization are discussed. Shortly the experimental approach for investigating redox-active proteins adsorbed on electrodes is outlined. Possible applications of redox enzymes in electrochemical biosensors and biofuel cells working by direct ET (DET) and mediated ET (MET) are presented. Furthermore, the reconstitution of redox active proteins at electrodes using molecular wire-like units in order to "wire" the proteins to the electrode surface and possible applications in nanotechnology are discussed. 相似文献
70.
Simple rules for the understanding of Heusler compounds 总被引:2,自引:0,他引:2
Heusler compounds are a remarkable class of intermetallic materials with 1:1:1 (often called Half-Heusler) or 2:1:1 composition comprising more than 1500 members. Today, more than a century after their discovery by Fritz Heusler, they are still a field of active research. New properties and potential fields of applications emerge constantly; the prediction of topological insulators is the most recent example. Surprisingly, the properties of many Heusler compounds can easily be predicted by the valence electron count. Their extremely flexible electronic structure offers a toolbox which allows the realization of demanded but apparently contradictory functionalities within one ternary compound. Devices based on multifunctional properties, i.e. the combination of two or more functions such as superconductivity and topological edge states will revolutionize technological applications. The subgroup of more than 250 semiconductors is of high relevance for the development of novel materials for energy technologies. Their band gaps can readily be tuned from zero to ≈4 eV by changing the chemical composition. Thus, great interest has been attracted in the fields of thermoelectrics and solar cell research. The wide range of their multifunctional properties is also reflected in extraordinary magneto-optical, magnetoelectronic, and magnetocaloric properties. The most prominent example is the combination of magnetism and exceptional transport properties in spintronic devices. To take advantage of the extremely high potential of Heusler compounds simple rules for the understanding of the structure, the electronic structure and the relation to the properties are reviewed. 相似文献