bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fassaden mit komplexer Geometrie – am Beispiel des Enzo Ferrari Museums in Modena
Authors: Blandini Lucio , Schmidt Timo , Winterstetter Thomas , Sobek Werner 
Published: March 2014

AbstractGebäude mit einer komplexen Fassadengeometrie bieten einen hohen Wiedererkennungswert und werden deshalb immer stärker nachgefragt. Unterstützt wird diese Entwicklung durch die raschen Fortschritte im Bereich der Planung und Fertigung von komplexen Geometrien. Am Beispiel des Enzo Ferrari Museums werden die Planungsprozesse und die technischen Lösungen erläutert, die die Realisierung einer solch komplexen Fassade auf höchstem gestalterischem und technischem Niveau ermöglicht haben. Die Fassade besteht zum einen aus einer geschwungenen transparenten Glaskonstruktion, die den Blick zum Geburtshaus von Enzo Ferrari lenkt; zum anderen besteht sie aus einem doppelt gekrümmten fugenlosen Aluminiumdach, das in Formensprache und Materialität an die Karosserie eines Sportwagens erinnert.Geometrically complex façades – The Enzo Ferrari Museum in Modena as a case studyGeometrically complex buildings have a strong iconic character and are therefore highly demanded by clients all over the world. This trend is also supported by the constant progress in the design and production of such façades. The article highlights different approaches towards the materialization of complex architectural surfaces and looks in more detail at the Enzo Ferrari Museum as an excellent case study. This highly expressive façade is composed of a curved glass envelope facing Enzo Ferrari's birth house as well as of a free‐form yellow aluminum roof, thus recalling materials and formal elements that are typical of sports car design.
Modell zur rechnerischen Abschätzung des Korrosionswiderstands von Beton
Authors: Scheydt Jennifer C. , Müller Harald S. 
Published: March 2014

AbstractAusgehend von einem Forschungsprojekt zur Dauerhaftigkeit von ultrahochfestem Beton wurde ein deterministisches Modell zur Abschätzung des Korrosionswiderstands von Beton gegenüber chemischem Angriff hergeleitet. Der Korrosionswiderstand ist abhängig vom ebenfalls abgeleiteten Gefügewiderstand, der den Widerstand des nicht korrodierten, ungerissenen Betons gegenüber dem Eindringen flüssiger oder gasförmiger Medien beschreibt. Das Modell basiert auf physikalischen Zusammenhängen und zeichnet sich durch eine vergleichsweise einfache Handhabung und eine hohe Praxistauglichkeit aus. Es dient dazu, dem Anwender die Auswahl eines für den Einsatz in korrosiver Umgebung geeigneten Betons zu erleichtern. In erster Näherung ist die Modellprognose auch dann möglich, wenn nur wenige Angaben zum Beton vorliegen (Zusammensetzung und Druckfestigkeit des Betons, chemische Zusammensetzung des Bindemittels). Nachfolgend wird das Modell zur Prognose des Korrosionswiderstands vorgestellt und seine Handhabung erläutert.Prediction of concrete resistance against corrosive attackWithin a research project on the durability of ultra high performance concrete, a model to predict the corrosion resistance of concrete against chemical attack was derived. The corrosion resistance depends on the structural resistance of the intact concrete against the ingress of liquid or gaseous media. The prediction model is based on physical properties and is characterised by an easy handling and a high suitability for the practical use. It is a helpful tool to find the concrete with the maximum resistance against an aggressive environment. Approximately, a prediction of the corrosion resistance is also possible if there is little information such as the composure or the compressive strength of the concrete and the chemical composure of the binder. In the following, the prediction model is introduced and its application is demonstrated.
Entwicklungsprinzipien und technische Grenzen der Herstellung zementarmer Betone
Authors: Haist Michael , Moffatt Jack S. , Breiner Raphael , Müller Harald S. 
Published: March 2014

AbstractDer vorliegende Beitrag erläutert die Prinzipien der Mischungsentwicklung zementarmer, besonders nachhaltiger Betone. Hierbei wird gezielt der Frage nachgegangen, wie weit der Zementgehalt von Beton reduziert werden kann, ohne dabei zentrale betontechnologische Kenngrößen wie die Verarbeitbarkeit oder die Betondruckfestigkeit negativ zu beeinflussen. Das Kernelement des hier vorgestellten Mischungsentwurfsalgorithmus bilden Methoden der Packungsdichteoptimierung, durch die der Wasseranspruch der Korngemische bestehend aus Zement, Gesteinsmehlen und Gesteinskörnung minimiert werden kann. Im vorliegenden Beitrag wir dabei ein kombinierter Ansatz, bestehend aus dem Kornverteilungsmodell von Funk und Dinger sowie des CIPM‐Modells von Fennis, vorgeschlagen. Die durchgeführten experimentellen Untersuchungen belegen, dass es damit gelingt, die Bindemittelintensität (d.h. den Zementbedarf zur Sicherstellung von 1 MPa an Druckfestigkeit in 1 m3 Beton) um einen Faktor von ca. 3 gegenüber Normalbeton zu reduzieren. Die Untersuchungsergebnisse zeigen darüber hinaus, dass die Verarbeitbarkeit der Betone in guter Näherung als Funktion des Quotienten aus der tatsächlichen Packungsdichte und der maximal möglichen Packungsdichte des Korngemisches vorhergesagt werden kann.Development principles and technical boundaries of concrete production with low cement contentThis paper explains the principles of proportioning ecologically sustainable, cement reduced concrete mixtures. It attempts to provide an answer to the question of how the cement content in concrete can be reduced without adversely affecting key characteristics, such as consistency and compressive strength. The central element of the proposed algorithm for mixture development consists of particle packing models, with which the water demand of the granular mixture of cement, stone dust and aggregate can be minimized. In this report a combined approach, consisting of the particle size distribution model of Funk and Dinger and the CIPM model of Fennis, is proposed. The experimental investigations carried out suggest that it is possible to reduce the binder intensity (the demand for binding material to produce 1 MPa of compressive strength in 1 m3 of concrete) of the concrete by a factor of ca. 3 as compared to normal concrete when following this approach. The experimental investigations also suggest that the workability of the mixtures can be estimated well by the quotient function between the actual particle packing density and a theoretical maximum particle packing density of the granular mixture.
Hotel Nagold – ein komplexes Stahlbetontragwerk in innerstädtischem Umfeld
Authors: Hinz Holger , Münich Christian 
Published: March 2014

AbstractDer siebenstöckige Neubau eines Hotels in Nagold scheint auf den ersten Blick – zumindest aus statischer Sicht – nur durchschnittlich komplex. Wie so oft liegt die Tücke aber im Detail. Bei diesem Projekt stellte die extrem hohe Anzahl an Abfang‐ und Lastumleitungsmaßnahmen besondere Anforderungen an die Tragwerksplanung. Zu erwähnen sind hierbei insbesondere die Abfangung von aussteifenden Wänden mittels Hochhängungen sowie die Anordnung von wandartigen (Krag‐)Trägern. Diese angesichts der relativ geringen Größe des Gebäudes überraschende Komplexität ist nicht zuletzt auf die sehr späte Einbindung des Tragwerksplaners in den Planungsablauf zurückzuführen. Die Einbindung erfolgte erst nach Abschluss des Architekturwettbewerbs, der eine Vielzahl von unterschiedlichen Nutzungen auf den einzelnen Ebenen vorsah. Aufgrund der zu berücksichtigenden Erdbebenzone und der extrem unregelmäßigen Tragwerksgeometrie wurden Nachweise nach dem Antwortspektrenverfahren erforderlich.Hotel Nagold – a complex reinforced concrete structure in inner‐city environmentAt first sight, the newly built seven‐storey hotel in Nagold, Germany, appears to be of only average complexity – that is at least from a structural point of view. However, as is often the case, the devil is in the detail. The extremely high number of support and load transfer measures required for this project place stringent demands on the structural design. The provision of supports for the bracing walls by means of elevation and the arrangement of the deep (cantilevered) beams are particularly worthy of mention. In view of the relatively small size of the building, the surprising level of complexity can be traced back to the fact that the structural design engineers were brought in at a very late stage of the planning process. The structural design engineers were not brought in until after the architectural competition, which envisaged a wide variety of different uses on the individual storeys, had been decided. The location in an earthquake zone and the extremely irregular geometry of the structure meant it was necessary to verify its structural safety utilizing the response spectrum method.
Ein Nachweiskonzept für die Querkrafttragfähigkeit verstärkter Stahlbetongurte von Verbundträgern im Bereich großer Stegöffnungen
Authors: Balzer Christian , Schnell Jürgen 
Published: March 2014

AbstractBei Stahlverbundträgern überträgt der Steg des Stahlträgers den größten Teil der Querkraft. Im Bereich von großen Stegöffnungen muss jedoch der Stahlbetongurt einen Großteil der Querkraftabtragung übernehmen. Die auf dem Stahlträgerflansch angeordneten Kopfbolzendübel dienen hier als Querkraftbewehrung. Durch den Einbau von zusätzlicher Querkraftbewehrung in Form von Dübelleisten im Betongurt seitlich neben dem Stahlträger kann die Traglast erheblich gesteigert werden.Die Untersuchung des Querkrafttragverhaltens des Stahlbetongurts von Verbundträgern, die im Bereich von großen Stegöffnungen mit Dübelleisten verstärkt sind, sowie die Erstellung eines Nachweiskonzepts waren die Hauptthemen eines an der TU Kaiserslautern durchgeführten Forschungsprojekts. Im vorliegenden Beitrag wird dieses Nachweiskonzept vorgestellt, welches es ermöglicht, bei der Bemessung von Verbundträgern, die durch Stegöffnungen geschwächt sind, durch einen geringen Mehreinsatz von Bewehrung in Form von Dübelleisten eine deutliche Traglaststeigerung zu erreichen.A design model to determine the shear load capacity of reinforced concrete chords of composite girders in the area of large web openingsThe web of the steel girder carries the most of the shear force of composite beams. If the web is weakened by a large opening the concrete chord has to transfer the shear force nearly completely. The headed studs on top of the steel girder serve as shear reinforcement. In several experiments the shear load capacity can be improved significantly by the arrangement of shear rails as further reinforcement in the concrete chord alongside large web openings.As part of a research project at the Kaiserslautern University of Technology, the influence of shear rails on the load bearing behavior of the concrete chord of composite beams with large web openings was investigated. In order to determine the shear load capacity of a concrete chord reinforced with shear rails, a design model was set up. This paper describes the design model that allows the structural design of composite girders in the area of web openings.
The effects of charge compensation on photoluminescence properties of a new green‐emitting ZnB2O4:Tb3+ phosphor
Authors: Liu Jie , Wu Zhan‐Chao , Wang Ping , Mei Yong‐Mei , Jiang Man , Kuang Shao‐Ping 
Published: March 2014

ABSTRACTCharge compensation is an effective way to eliminate charge defects and improve the luminescent intensity of phosphors. In this paper, a new green‐emitting phosphor ZnB2O4:Tb3+ was prepared by solid‐state reaction at 750°C. The effects of Tb3+ doping content and charge compensators (Li+, Na+ or K+) on photoluminescence properties of ZnB2O4:Tb3+ were investigated. X‐ray powder diffraction analysis confirms the sample has cubic structure of ZnB2O4. The excitation and emission spectra indicate that this phosphor can be excited by near ultraviolet light at 378 nm, and exhibits bright green emission with the highest peak at 544 nm corresponding to the 5D4→7F5 transition of Tb3+. The critical quenching concentration of Tb3+ in ZnB2O4 host is 8 mol%. The results of charge compensation show that the emission intensity can be improved by Na+ and K+. Specifically, K+ is the optimal one for ZnB2O4:Tb3+. Copyright © 2014 John Wiley & Sons, Ltd.
Changes in highly sensitive alpha‐fetoprotein for the prediction of the outcome in patients with hepatocellular carcinoma after hepatectomy
Authors: Toyoda Hidenori , Kumada Takashi , Tada Toshifumi , Ito Takanori , Maeda Atsuyuki , Kaneoka Yuji , Kagebayashi Chiaki , Satomura Shinji 
Published: March 2014

AbstractWe investigated changes in highly sensitive lens culinaris agglutinin A‐reactive fraction of alpha‐fetoprotein (hsAFP‐L3) measured using a novel method and its predictive ability for prognosis in patients with hepatocellular carcinoma (HCC) who underwent curative hepatectomy, comparing to other HCC tumor markers, that is, AFP, des‐gamma‐carboxy prothrombin (DCP), and AFP‐L3 measured with conventional method (cAFP‐L3). AFP, DCP, and AFP‐L3 including both cAFP‐L3 and hsAFP‐L3 were measured before and after curative hepatectomy in 187 patients. The percentage of patients with elevated tumor marker levels pre‐ and postoperatively was compared, and recurrence‐free and overall survival rates were analyzed based on changes in tumor markers. The percentages of patients with elevated AFP, DCP, and cAFP‐L3 decreased postoperatively. In contrast, the percentage of patients with elevated hsAFP‐L3 did not decrease postoperatively. Both recurrence‐free and overall survival rates were significantly lower in patients whose tumor marker levels remained elevated postoperatively than patients without tumor marker elevation postoperatively. Recurrence‐free and overall survival rates of patients in whom hsAFP‐L3 became elevated postoperatively despite normal preoperative hsAFP‐L3 levels were significantly lower than those of patients with normal hsAFP‐L3 postoperatively, and were similar to those of patients with persistent elevation. Preoperative elevations of AFP, DCP, and cAFP normalized in many patients postoperatively, but not for hsAFP‐L3. The elevation of hsAFP‐L3 identifies patients with poor prognosis despite the normalization of AFP and DCP.
Evolution of Iron(II)‐Finger Peptides by Using a Bipyridyl Amino Acid
Authors: Kang Mingchao , Light Kenneth , Ai Hui‐wang , Shen Weijun , Kim Chan Hyuk , Chen Peng R. , Lee Hyun Soo , Solomon Edward I. , Schultz Peter G. 
Published: March 2014

AbstractWe report the engineering of zinc‐finger‐like motifs containing the unnatural amino acid (2,2′‐bipyridin‐5‐yl)alanine (Bpy‐Ala). A phage‐display library was constructed in which five residues in the N‐terminal finger of zif268 were randomized to include both canonical amino acids and Bpy‐Ala. Panning of this library against a nine‐base‐pair DNA binding site identified several Bpy‐Ala‐containing functional Zif268 mutants. These mutants bind the Zif268 recognition site with affinities comparable to that of the wild‐type protein. Further characterization indicated that the mutant fingers bind low‐spin FeII rather than ZnII. This work demonstrates that an expanded genetic code can lead to new metal ion binding motifs that can serve as structural, catalytic, or regulatory elements in proteins.
Traumatic dissection of the internal carotid artery: simultaneous infarct of optic nerve and brain
Authors: Correa Edgar , Martinez Braulio 
Published: March 2014

Key Clinical MessageTraumatic intracranial internal carotid artery dissection is a rare but significant cause of stroke in patients in their forties, leading to high morbidity and mortality. Simultaneous ischemic stroke and optic nerve infarction can occur. Clinical suspicion of dissection is determining in the acute management.
Active Site Plasticity of a Computationally Designed Retro‐Aldolase Enzyme
Authors: Obexer Richard , Studer Sabine , Giger Lars , Pinkas Daniel M. , Grütter Markus G. , Baker David , Hilvert Donald 
Published: March 2014

AbstractRA110 is a computationally designed retro‐aldolase enzyme that utilizes amine catalysis to convert 4‐hydroxy‐4‐(6‐methoxy‐2‐naphthyl)‐2‐butanone to 6‐methoxy‐2‐naphthaldehyde and acetone. The original design accelerated substrate cleavage by a factor of 12 000 over background, and its activity was subsequently increased more than a thousand‐fold by directed evolution. The X‐ray structure of the evolved catalyst covalently modified with a 1,3‐diketone inhibitor deviates substantially from the design model, however, with the ligand adopting a completely different orientation than predicted. Moreover, significant activity was maintained even after relocation of the reactive lysine within the apolar binding pocket. These results suggest that the success of the original design is not ascribable to atomically accurate molecular recognition, but rather to successful placement of a reactive lysine adjacent to an apolar binding pocket. Nevertheless, the stabilizing interactions observed at the active site of the evolved variant suggest that improvements in the precision of design calculations will afford enzymes with higher catalytic activities.
Nanoporous Polymers: Bridging the Gap between Molecular and Solid Catalysts?
Authors: Rose Marcus 
Published: March 2014

AbstractThe combination of the advantageous properties of molecular and solid catalysts is considered the “Holy Grail” in catalysis research. Great potential is provided by nanoporous polymers. Chemically well‐defined moieties in combination with a high stability render these materials suitable as catalyst supports for liquid‐phase and even aqueous‐phase catalytic processes, especially regarding the transition from fossil resources to renewable resources. In this Minireview, recent developments are summarized, covering the three main approaches: solid metal‐free organocatalysts, immobilized molecular catalyst species, and supported metal nanoparticles and clusters. Their potential is evaluated and the question as to whether nanoporous polymers can bridge the gap between homogeneous and heterogeneous catalysis is critically discussed.
Single‐Particle Spectroscopy of Alcohol‐to‐Olefins over SAPO‐34 at Different Reaction Stages: Crystal Accessibility and Hydrocarbons Reactivity
Authors: Qian Qingyun , Ruiz‐Martínez Javier , Mokhtar Mohamed , Asiri Abdullah M. , Al‐Thabaiti Shaeel A. , Basahel Suliman N. , Weckhuysen Bert M. 
Published: March 2014

AbstractThe front cover artwork for Issue 3/2014 is provided by the Inorganic Chemistry and Catalysis group of Utrecht University. The image shows the concept of synchrotron‐based IR and UV/Vis microspectroscopy monitoring a catalytic reaction on a single SAPO‐34 crystal and the obtained spatially resolved information on the retained hydrocarbon species and crystal accessibility. See the Full Paper itself on http://dx.doi.org/10.1002/cctc.201300962.
Synthesis and Spin‐Trapping Properties of a Trifluoromethyl Analogue of DMPO: 5‐Methyl‐5‐trifluoromethyl‐1‐pyrroline N‐Oxide (5‐TFDMPO)
Authors: Karoui Hakim , Nsanzumuhire Céline , Le Moigne François , Hardy Micael , Siri Didier , Derat Etienne , Rockenbauer Antal , Ouari Olivier , Tordo Paul 
Published: March 2014

AbstractThe 5‐diethoxyphosphonyl‐5‐methyl‐1‐pyrroline N‐oxide superoxide spin adduct (DEPMPOOOH) is much more persistent (about 15 times) than the 5,5‐dimethyl‐1‐pyrroline N‐oxide superoxide spin adduct (DMPOOOH). The diethoxyphosphonyl group is bulkier than the methyl group and its electron‐withdrawing effect is much stronger. These two factors could play a role in explaining the different half‐lifetimes of DMPOOOH and DEPMPOOOH. The trifluoromethyl and the diethoxyphosphonyl groups show similar electron‐withdrawing effects but have different sizes. We have thus synthesized and studied 5‐methyl‐5‐trifluoromethyl‐1‐pyrroline N‐oxide (5‐TFDMPO), a new trifluoromethyl analogue of DMPO, to compare its spin‐trapping performance with those of DMPO and DEPMPO. 5‐TFDMPO was prepared in a five‐step sequence by means of the Zn/AcOH reductive cyclization of 5,5,5‐trifluoro‐4‐methyl‐4‐nitropentanal, and the geometry of the molecule was estimated by using DFT calculations. The spin‐trapping properties were investigated both in toluene and in aqueous buffer solutions for oxygen‐, sulfur‐, and carbon‐centered radicals. All the spin adducts exhibit slightly different fluorine hyperfine coupling constants, thereby suggesting a hindered rotation of the trifluoromethyl group, which was confirmed by variable‐temperature EPR studies and DFT calculations. In phosphate buffer at pH 7.4, the half‐life of 5‐TFDMPOOOH is about three times shorter than for DEPMPOOOH and five times longer than for DMPOOOH. Our results suggest that the stabilization of the superoxide adducts comes from a delicate balance between steric, electronic, and hydrogen‐bonding effects that involve the β group, the hydroperoxyl moiety, and the nitroxide.
Ytterbium(III) Porpholactones: β‐Lactonization of Porphyrin Ligands Enhances Sensitization Efficiency of Lanthanide Near‐Infrared Luminescence
Authors: Ke Xian‐Sheng , Yang Bo‐Yan , Cheng Xin , Chan Sharon Lai‐Fung , Zhang Jun‐Long 
Published: March 2014

AbstractThe near‐infrared (NIR) luminescence efficiency of lanthanide complexes is largely dependent on the electronic and photophysical properties of antenna ligands. Although porphyrin ligands are efficient sensitizers of lanthanide NIR luminescence, non‐pyrrolic porphyrin analogues, which have unusual symmetry and electronic states, have been much less studied. In this work, we used porpholactones, a class of β‐pyrrolic‐modified porphyrins, as ligands and investigated the photophysical properties of lanthanide porpholactones Yb‐1 a–5 a. Compared with Yb porphyrin complexes, the porpholactone complexes displayed remarkable enhancement of NIR emission (50–120 %). Estimating the triplet‐state levels of porphyrin and porpholactone in Gd complexes revealed that β‐lactonization of porphyrinic ligands lowers the ligand T1 state and results in a narrow energy gap between this state and the lowest excited state of Yb3+. Transient absorption spectra showed that YbIII porpholactone has a longer transient decay lifetime at the Soret band than the porphyrin analogue (30.8 versus 17.0 μs). Thus, the narrower energy gap and longer lifetime arising from β‐lactonization are assumed to enhance NIR emission of Yb porpholactones. To demonstrate the potential applications of Yb porpholactone, a water‐soluble Yb bioprobe was constructed by conjugating glucose to Yb‐1 a. Interestingly, the NIR emission of this Yb porpholactone could be specifically switched on in the presence of glucose oxidase and then switched off by addition of glucose. This is the first demonstration that non‐pyrrolic porphyrin ligands enhance the sensitization efficiency of lanthanide luminescence and also display switchable NIR emission in the region of biological analytes (800–1400 nm).