bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fourier Transform EPR Spectroscopy of Trityl Radicals for Multifunctional Assessment of Chemical Microenvironment
Authors: Bobko Andrey A. , Dhimitruka Ilirian , Zweier Jay L. , Khramtsov Valery V. 
Published: February 2014

AbstractPulse techniques in electron paramagnetic resonance (EPR) allow for a reduction in measurement times and increase in sensitivity but require the synthesis of paramagnetic probes with long relaxation times. Here it is shown that the recently synthesized phosphonated trityl radical possesses long relaxation times that are sensitive to probe the microenvironment, such as oxygenation and acidity of an aqueous solution. In principle, application of Fourier transform EPR (FT‐EPR) spectroscopy makes it possible to acquire the entire EPR spectrum of the trityl probe and assess these microenvironmental parameters within a few microseconds. The performed analysis of the FT‐EPR spectra takes into consideration oxygen‐, proton‐, buffer‐, and concentration‐induced contributions to the spectral shape, therefore enabling quantitative and discriminative assessment of pH, pO2, and concentrations of the probe and inorganic phosphate.
Frame‐Guided Assembly of Vesicles with Programmed Geometry and Dimensions
Authors: Dong Yuanchen , Sun Yawei , Wang Liying , Wang Dianming , Zhou Tao , Yang Zhongqiang , Chen Zhong , Wang Qiangbin , Fan Qinghua , Liu Dongsheng 
Published: February 2014

AbstractIn molecular self‐assembly molecules form organized structures or patterns. The control of the self‐assembly process is an important and challenging topic. Inspired by the cytoskeletal‐membrane protein lipid bilayer system that determines the shape of eukaryotic cells, we developed a frame‐guided assembly process as a general strategy to prepare heterovesicles with programmed geometry and dimensions. This method offers greater control over self‐assembly which may benefit the understanding of the formation mechanism as well as the functions of the cell membrane.
Nucleophile‐Dependent Regio‐ and Stereoselective Ring Opening of 1‐Azoniabicyclo[3.1.0]hexane Tosylate
Authors: Ji Mi‐Kyung , Hertsen Dietmar , Yoon Doo‐Ha , Eum Heesung , Goossens Hannelore , Waroquier Michel , Van Speybroeck Veronique , D'hooghe Matthias , De Kimpe Norbert , Ha Hyun‐Joon 
Published: February 2014

Abstract1‐[(1R)‐(1‐Phenylethyl)]‐1‐azoniabicyclo[3.1.0]hexane tosylate was generated as a stable bicyclic aziridinium salt from the corresponding 2‐(3‐hydroxypropyl)aziridine upon reaction with p‐toluenesulfonyl anhydride. This bicyclic aziridinium ion was then treated with various nucleophiles including halides, azide, acetate, and cyanide in CH3CN to afford either piperidines or pyrrolidines through regio‐ and stereoselective ring opening, mediated by the characteristics of the applied nucleophile. On the basis of DFT calculations, ring‐opening reactions under thermodynamic control yield piperidines, whereas reactions under kinetic control can yield both piperidines and pyrrolidines depending on the activation energies for both pathways.
Nanowire Shish‐Kebab Structures and Molecular Orientation Control of All‐Conjugated Diblock Copolymers
Authors: Yang Hua , Wang Lei , Yu Xinhong , Zhang Jidong , Geng Yanhou , Han Yanchun 
Published: February 2014

AbstractHerein we propose a facile strategy to prepare nanowires and nanowire “shish‐kebab” (NWSK) structures by controlling the crystallization behavior of all‐conjugated rod–rod diblock copolymers poly[(p‐phenylene)‐block‐(3‐hexylthiophene)]s (PPP‐b‐P3HT (BmTn)) with varying main chain lengths. Depending on the block length and ratio (i.e., PPP/P3HT, abbreviated as B/T), nanowires with low B/T ratios (copolymers with long P3HT blocks; B8T32 and B14T34) and NWSKs with high B/T ratios (copolymers with long PPP blocks; B29T9 and B39T18) were formed for PPP‐b‐P3HT all‐conjugated diblock copolymers. The formation of nanowires is governed by a strong interchain π–π stacking similar to the P3HT homopolymer, with an edge‐on orientation of the P3HT moiety, whereas NWSKs are formed as a result of the particular face‐on molecular orientation of PPP moiety. As the length of the P3HT moiety was increased (the block ratio of PPP/P3HT reduced), the NWSKs were transformed into nanowires gradually because of the decreasing density of “kebabs”. For diblock copolymers with high PPP/P3HT ratios, the transition of the molecular orientation from face‐on to edge‐on was obtained by thermal annealing.
Synthesis of New Diphosphine Ligands and their Application in Pd‐Catalyzed Alkoxycarbonylation Reactions
Authors: Pews‐Davtyan Anahit , Fang Xianjie , Jackstell Ralf , Spannenberg Anke , Baumann Wolfgang , Franke Robert , Beller Matthias 
Published: February 2014

AbstractCarbocyclic and N‐heterocyclic analogues of the industrially applied ligand bis(di‐tert‐butylphosphinomethyl)benzene (1) have been synthesized in moderate to very good yields. The new ligands are based on benzene, tetralin, lutidine, pyrazine, quinoxaline, and maleimide backbones. Electronic and steric variations of the phosphorous donor sites were performed. As a benchmark reaction, the palladium‐catalyzed methoxycarbonylation of 1‐octene has been tested. Ester yields up to 64 % and high linear selectivities up to 92 % were achieved.
Base‐Line‐gestützte Verformungsmessungen an einer semi‐integralen Hohlkastenbrücke
Authors: von der Haar Christoph , Marx Steffen , Bolle Guido 
Published: February 2014

AbstractVerformungsmessungen an Brückentragwerken können im Rahmen von Monitoringmaßnahmen aufschlussreiche Informationen zum Tragverhalten und zum Bauwerkszustand liefern. Geodätische Messverfahren werden für diese Durchbiegungsmessungen bevorzugt eingesetzt. Diese Verfahren ermöglichen reflektorlose und messbasisfreie Verformungsmessungen bei Abtastraten von mehreren hundert Kilohertz. Die eingesetzten Laserscanner sind in der Regel sehr teuer, wodurch diese bei Messperioden von mehreren Wochen oder Jahren und gemäßigten Genauigkeitsanforderungen an Attraktivität verlieren. Demgegenüber wird in diesem Beitrag ein relativ preiswertes Verfahren für Verformungsmessungen an Hohlkastenbrücken vorgestellt. Bei diesem Verfahren wird ein Seil oder Draht durch das Brückenbauwerk gespannt. Dieses fungiert als verformungsneutrale Messbasis (“Base‐Line”) und ermöglicht die Messwertaufnahme bzw. die Verformungsmessung mit optischen Wegaufnehmern. Dieses Messverfahren wird im Zuge von Testmessungen an einer semi‐integralen Spannbeton‐Talbrücke im Zuge der Europastraße E18 in Norwegen eingesetzt. Die Voruntersuchungen zu dem Messverfahren, durchgeführte Probemessungen an einer Hohlkastenbrücke im Stadtgebiet von Hannover und erste Ergebnisse der Testmessungen an der Talbrücke in Norwegen werden im folgenden Beitrag präsentiert.Base‐line deformation measurements on a semi‐integral box girder bridgeDeformation measurements as part of monitoring activities can provide information about the behavior and structural condition of bridge structures. Geodetic measurement methods are preferred for these deflection measurements. These methods allow reflectorless measurements at sampling rates of several hundred kilohertz. But the used laser scanners are very expensive, by this they are losing attractiveness for measurement periods of several weeks or years and in case of moderate accuracy requirements. In contrast, a relatively inexpensive method to measure the deformations of box girder bridges is presented in this paper. In this method, a cable or wire is clamped through the bridge structure. This acts as measurement base (“base‐line") and allows deformation measurements by optical transducers. This measurement method is currently being tested as part of a monitoring program at a semi‐integral viaduct in Norway. Preliminary studies of the measurement method, conducted measurements on a box girder bridge near of Hanover and first results of test measurements at the Norwegian viaduct are presented.
Die Baakenhafenbrücke – innovative Nutzungsvielfalt und Nachhaltigkeit
Authors: Liebig Henning , Rogers Paul , Trumpf Heiko , Eyre Jim , Graubner Carl‐Alexander , Gnauert Jörg , Proost Mike , Vreven Koen 
Published: February 2014

AbstractIm August 2013 wurde die Baakenhafenbrücke eröffnet und der Öffentlichkeit übergeben. Die Brücke wurde am größten Hafenbecken der neuen Hamburger HafenCity realisiert und ist die infrastrukturelle Voraussetzung für die dichte Mischung aus Wohn‐ und Freizeitnutzung, grünen Freiräumen und Arbeitsplätzen am Hafenbecken. Zugleich genügt sie den vielfältigen Nutzungsanforderungen einer modernen, nachhaltigen Stadtentwicklung, schafft Aufenthaltsräume und bindet sich harmonisch ins Umfeld ein, ohne Barrieren zu bilden.Die Brücke kann sowohl zu Fuß als auch mit dem Fahrrad oder Auto überquert werden. Für Fußgänger ist eine besonders attraktive Lösung entwickelt worden: Zwei getrennt von der Fahrbahn geführte, geschwungene Gehwege, die der Brücke ihre charakteristische Form verleihen, bieten in ihren Wölbungen einladende Aussichtspunkte und Sitzgelegenheiten und laden zum Verweilen ein. In Bezug auf Entwicklung und Nachhaltigkeit geht von dem Brückenbauprojekt eine starke Signalwirkung aus, die weit über die Grenzen der HafenCity hinaus Einfluss nehmen wird.The Baakenhafen bridge – Innovative, multifunctional and sustainableOpened in August 2013 the new Baakenhafen bridge is an important piece of urban infrastructure, unlocking a key site on the HafenCity development in Hamburg. In the short term, the bridge will serve as a means of access to the Baakenhafen peninsula for the site wide construction effort. Following this wave of development, the bridge will serve its primary purpose of connecting the inhabitants and users of this new district with the city to the North. For this reason, the bridge has been designed to accommodate several modes of travel: vehicular, bicycle and pedestrian. The bridge provides generous footpaths along both edges, isolated from vehicular traffic, creating a quiet, protected environment. The rise and fall of these footpaths provide unique views in all directions. While the footpath dips towards the water it also swells in width creating a generous terraced seating area. Pedestrians are invited to sit and use the bridge as a destination as well as a connection. The impact of the bridge will be felt far beyond the extent of its immediate site as it acts as a catalyst for development and regeneration on a neighbourhood scale.
Dalsfjordbrua – 523 Meter Hängebrücke in Westnorwegen
Authors: Methner Raphael 
Published: February 2014

AbstractIm Zuge des kontinuierlichen Ausbaus der norwegischen Infrastruktur erfolgt seit September 2010 die endgültige Fertigstellung der Dalsfjordverbindung an der Westküste Norwegens. Neben etwa 3, 8 Kilometer Tunnelkonstruktion ist der Bau der Dalsfjord‐Hängebrücke der bedeutungsvollste Bestandteil dieser Neubaumaßnahme. In diesem Beitrag werden die wesentlichen Betonarbeiten der Hängebrücke erläutert. Diese umfassen die Tragseilverankerungen, die Pylone sowie die Vorlandbrücken. Neben der Darstellung von Ausführungsthemen wird auf die projektspezifischen Besonderheiten eingegangen. Speziell Wetter, Strömungen und (in den Wintermonaten) wenig Sonnenlicht sowie die begrenzte Verfügbarkeit von Baustoffen und Maschinen erforderten eine detaillierte Arbeitsvorbereitung. Zudem erschwerten begrenzte Zugangsmöglichkeiten und geringe Ausweichflächen die Ausführung.Dalsfjordbrua – 523 meters suspension bridge in western NorwayAs part of the continuous expansion of the Norwegian infrastructure since September 2010, the final completion of the Dalsfjord connection has started on the west coast of Norway. In addition to approximately 3.8 kilometer of tunnel construction, building the Dalsfjord suspension bridge is the most significant part of this new connection. In this paper, the essential works of the concrete suspension bridge are explained. These include the cable anchorages, the pylons and the approach bridges. Besides the representation of construction details, in particular project‐specific features are presented. Especially weather, currents and limited sunlight (during winter months) as well as the limited availability of building materials and machinery required a detailed work preparation. In addition limited access and little alternative areas had made execution difficult.
Untersuchung einer 50 Jahre alten Spannbetonbrücke zur Genauigkeitssteigerung von Lebensdauerprognosen
Authors: Sanio David , Ahrens Mark Alexander , Mark Peter , Rode Sonja 
Published: February 2014

AbstractDie Belastung bestehender Infrastruktur nimmt stetig zu. Bauwerke, insbesondere Brücken, müssen heute deutlich höheren Lasten standhalten als zum Zeitpunkt ihrer Planung und Erbauung. Insbesondere Ermüdung ist bei der Überprüfung und Nachrechnung der Bauwerke ein wesentlicher Aspekt, der in der Vergangenheit schon zu Schadensfällen geführt hat. Im Rahmen des DFG‐Forschungsprojekts “Genauigkeitsgrenzen von Lebensdauerprognosen – Experimentelle und numerische Untersuchung einer Spannbetonhochstraße unter Ermüdungsbeanspruchung” konnte an einer über 50 Jahre alten Spannbetonbrücke in Düsseldorf ein umfangreiches Bauwerksmonitoring (Komponenten: Dauermessung von Spannstahl‐ und Betondehnungen, Prüfung von Materialproben, Probebelastung, usw.) des Bauwerks durchgeführt werden. Es wird gezeigt, wie die generelle Unsicherheit, die mit Lebensdauerprognosen einhergeht, gezielt reduziert werden kann und sich dadurch die rechnerische Lebensdauer um ein Vielfaches verlängert. Unter “bestmöglichen Bedingungen” – experimentell fundierter Kenntnis relevanter Eingangsgrößen – werden die Auswirkungen diverser Parameter (Material, Verkehrslasten, Strukturmodell, usw.) herausgearbeitet und ihre Beiträge auf die Prognosequalität quantifiziert. Dazu werden zunächst das Bestandsbauwerk, dann der Ersatzneubau sowie die Situation im Heerdter Dreieck in Düsseldorf, die eine spezielle Planung erforderte, erläutert.Increasing the accuracy of lifetime prediction by structural monitoring of a 50‐year old pre‐stressed concrete bridgeDemands on the existent infrastructure are continuously rising. Today, structures, especially bridges, have to resist significantly increased loads compared to the ones scheduled during projection and erection. In course of inspections and reassessments fatigue turned out to be of high‐relevance and even led to cases of severe damage in the past. In the DFG‐funded research project “Precision limits of lifetime prognoses – experimental and numerical investigation of an existent bridge structure subjected to fatigue” focus has been set on substantial structural monitoring of a 50‐year old pre‐stressed concrete bridge located in Düsseldorf. The measures comprise among others long‐time recording of strains (concrete and tendons), material testing and trial loading. It is shown how to capture and systematically reduce inherent uncertainty of lifetime predictions. Thereby the computed structural lifetime considerably increases. In a “best case scenario”, where comprehensive experimental input data is at hand, single parameters (e.g.: material, traffic loads, and structural model) impact on the prognosis as well as on its belonging precision has been quantified. Therefore both, the existent as well as the newly erected structure in the context of Heerdter Dreieck in Düsseldorf which demands for specific projection measures are elucidated.
Ergebnisse und Erkenntnisse zu durchgeführten Nachrechnungen von Betonbrücken in Deutschland
Authors: Fischer Oliver , Müller Andreas , Lechner Thomas , Wild Matthias , Kessner Kathrin 
Published: February 2014

AbstractZur Vereinheitlichung der Vorgehensweise bei der Nachrechnung von Straßenbrücken wurde in Deutschland im Mai 2011 die “Nachrechnungsrichtlinie” eingeführt. Im Rahmen eines von der deutschen Bundesanstalt für Straßenwesen (BASt) initiierten und von den Autoren des vorliegenden Beitrags bearbeiteten Forschungsvorhabens wurden in den vergangenen Monaten Nachrechnungsergebnisse zu insgesamt 146 Betonbrücken aus ganz Deutschland gesammelt und ausgewertet. Wesentliches Ziel des Projekts war es, Grundlagen für eine noch effizientere Nachrechnung mit aussagekräftigen Ergebnissen zu schaffen. Nachfolgend werden zunächst typische “rechnerische Defizite” benannt, welche Zusatzbetrachtungen erforderlich machen, die über die Anwendung der Sonderregelungen der Nachweisstufe 2 hinausgehen. Anschließend werden Empfehlungen zur Nachrechnung allgemein sowie zum Umgang mit rechnerischen Defiziten gegeben und es werden Vorschläge zur Aufbereitung von Nachrechnungsergebnissen vorgestellt und diskutiert.Findings and insights concerning the results of re‐analyzed concrete bridges in GermanyIn May 2011 the new guideline “Nachrechnungsrichtlinie” (standard for bridge re‐analysis and assessment) was recommended for application in order to implement a harmonized basis for the assessment of existing road bridges. Within the framework of a research project initiated and funded by the Federal Highway Research Institute (BASt) re‐analysis results of in total 146 concrete bridges were collected and evaluated. One major goal of this project was to provide a basis for a more efficient re‐analysis and an improved documentation of the results. The present paper firstly describes typical “calculatory deficits” requiring additional considerations upon completion of the so‐called re‐analysis stage 2. Subsequently, general recommendations for future re‐analyses are being provided, advices are given in terms of the handling of deficits and a proposal is made and discussed regarding presentation and documentation of re‐analysis results.
The Dark Side of Hydrogen Bonds in the Design of Optical Materials: A Charge‐Density Perspective
Authors: Nelyubina Yulia V. , Puntus Lada N. , Lyssenko Konstantin A. 
Published: February 2014

AbstractA combined investigation of the structural, electronic, and optical properties of three crystalline nonaaqualanthanoid(III) triflates, [Ln(H2O)9(CF3SO3)3], has provided unambiguous experimental evidence for charge redistribution in the first coordination sphere of a lanthanide ion as a result of hydrogen bonds with outer‐sphere anions. As well as resulting in charge transfer from the noncoordinated anions to the coordinated water molecules, these hydrogen bonds give rise to a new excited state, an hydrogen‐bond‐induced charge‐transfer state, which is observed experimentally for the first time. This state was shown to be responsible for the previously unknown negative aspect of hydrogen bonds with a lanthanide‐bound water molecule: rather than increasing the luminescence efficiency of the complex, they can lead to additional quenching that is unfavorable for the task‐specific design of optical materials.
Grafting Perylenes to ZnO Nanoparticles
Authors: Schönamsgruber Jörg , Zeininger Lukas , Hirsch Andreas 
Published: February 2014

AbstractA new prototype of dendritic perylenes suitable for the chemical functionalization of inorganic nanoparticles was synthesized and characterized. The bay‐functionalized perylene core of these molecular architectures was coupled to a catechol moiety, which serves as an anchor group for the functionalization of metal oxides, in particular ZnO. To increase the solubility of both the perylene and the targeted hybrid nanostructures, a Newkome‐type dendron bearing nine positive charges was introduced. This charge was also employed to stabilize the nanoparticles and further protect them from Ostwald ripening through Coulombic repulsion. ZnO quantum dots with an average diameter of 5 nm were synthesized and functionalized with the perylene derivative. Successful functionalization was clearly demonstrated by dynamic light scattering, zeta‐potential measurements, thermogravimetric analysis/MS, and UV/Vis and fluorescence spectroscopy. The generated particle dispersions were stable against agglomeration for more than eight weeks.
Reversible Binding of Solvent to Naked PbII Centers in Unusual Homoleptic Alkynyl‐Based Pt2Pb2 Clusters
Authors: Berenguer Jesús R. , Fernández Julio , Gil Belén , Lalinde Elena , Sánchez Sergio 
Published: February 2014

AbstractWe report a series of luminescent sandwich‐type clusters [Pt2Pb2(C≡CR)8] (R=Tol, 1; C6H4OMe‐3, 2; C6H4OMe‐4, 3) with a dynamic Pt2Pb2 metallic core, which is key to their intriguing stimuli‐responsive photophysical properties. The solvent‐free solids 1–3 display an orange emission ascribed to charge transfer from Pt–alkynyl fragments to a delocalized orbital with mixed Pt2Pb2/C≡CR nature, with a predominant lead contribution and Pb⋅⋅⋅Pb bonding character (3MLCCT/3IL). They exhibit mechanical, color, and luminescence changes that are reversible and perceivable with the naked eye, which are attributed to small inter‐ and intramolecular structural modifications induced by gentle grinding. Interestingly, 1 and 2 also exhibit remarkable and fast reversible vapochromic responses to donor solvent vapors (acetone, THFMe‐2: yellow; NCMe: green, vs. dry solids: orange). The structures of 1(acetone)2⋅2(Me2CO), 2(acetone)3, and 2(THFMe‐2)2 allow the vapochromic responses to be ascribed to the fast creation/disruption of solvate clusters [Pt2Pb2(C≡CR)8Sx] (x≥2), with concomitant electronic and geometrical modifications within the Pt2Pb2 core, which are easily accessible through a slight change in the stereochemical activity of the lone pair. The binding of one (or two) solvent molecules to Pb2+ increases the Pb⋅⋅⋅Pb separation in the metallic core, causing a destabilization of the target orbital and larger energy gaps of the transitions. All the solvates exhibit remarkable rigidochromism upon a decrease in temperature, which is also associated with the gradual increase in the transannular Pb⋅⋅⋅Pb separation, as revealed by X‐ray crystallography of 1(acetone)2 at different temperatures. Investigation of the crystal lattice of 1⋅CH2Cl2 and 3⋅2 CH2Cl2 further suggests that the lack of vapor stimuli response of complex 3 could be attributed to the presence of competitive additional secondary intermolecular Pb⋅⋅⋅O(OMe) contacts, which give rise to a more compact network built up from extended chains of clusters.
Synthesis of 2,5‐Diaryl‐Substituted Thiophenes as Helical Mimetics: Towards the Modulation of Islet Amyloid Polypeptide (IAPP) Amyloid Fibril Formation and Cytotoxicity
Authors: Hassanpour Avid , De Carufel Carole Anne , Bourgault Steve , Forgione Pat 
Published: February 2014

AbstractA range of 2,5‐diarylated thiophenes were synthesised as small molecule mimetics of the α‐helix to modulate the amyloidogenesis and cytotoxic effect of islet amyloid polypeptide (IAPP). 3‐Substituted thiophene‐2‐carboxylic acids were used as key intermediates and functionalised by palladium decarboxylative cross‐coupling and direct CH activation successively with overall yields ranging from 23 to 95 %. The effect of the ligands on IAPP amyloid fibril formation was evaluated with the thioflavin T (ThT) fluorescence‐based assay. Furthermore, the capacity of these compounds to inhibit the cytotoxic effect of IAPP was assessed using β‐pancreatic cells.