bluuebunny/crossref_metadata_2025 huggingface dataset:
Receiver function images of the Hellenic subduction zone and comparison to microseismicity
Authors: Sodoudi F. , Brüstle A. , Meier T. , Kind R. , Friederich W. ,   EGELADOS working group
Published: February 2015

Abstract. New combined P receiver functions and seismicity data obtained from the EGELADOS network employing 65 seismological stations within the Aegean constrained new information on the geometry of the Hellenic subduction zone. The dense network and large data set enabled us to estimate the Moho depth of the continental Aegean plate across the whole area. Presence of a negative contrast at the Moho boundary indicating the serpentinized mantle wedge above the subducting African plate was seen along the entire forearc. Furthermore, low seismicity was observed within the serpentinized mantle wedge. We found a relatively thick continental crust (30–43 km) with a maximum thickness of about 48 km beneath the Peloponnese Peninsula, whereas a thinner crust of about 27–30 km was observed beneath western Turkey. The crust of the overriding plate is thinning beneath the southern and central Aegean and reaches 23–27 km. Unusual low Vp / Vs ratios were estimated beneath the central Aegean, which most likely represent indications on the pronounced felsic character of the extended continental Aegean crust. Moreover, P receiver functions imaged the subducted African Moho as a strong converted phase down to a depth of about 100 km. However, the converted Moho phase appears to be weak for the deeper parts of the African plate suggesting nearly complete phase transitions of crustal material into denser phases. We show the subducting African crust along eight profiles covering the whole southern and central Aegean. Seismicity of the western Hellenic subduction zone was taken from the relocated EHB-ISC catalogue, whereas for the eastern Hellenic subduction zone, we used the catalogues of manually picked hypocentre locations of temporary networks within the Aegean. Accurate hypocentre locations reveal a significant change in the dip angle of the Wadati–Benioff zone (WBZ) from west (~ 25°) to the eastern part (~ 35°) of the Hellenic subduction zone. Furthermore, a zone of high deformation can be characterized by a vertical offset of about 40 km of the WBZ beneath the eastern Cretan Sea. This deformation zone may separate a shallower N-ward dipping slab in the west from a steeper NW-ward dipping slab in the east. In contrast to hypocentre locations, we found very weak evidence for the presence of the slab at larger depths in the P receiver functions, which may result from the strong appearance of the Moho multiples as well as eclogitization of the oceanic crust. The presence of the top of a strong low-velocity zone at about 60 km depth in the central Aegean may be related to the asthenosphere below the Aegean continental lithosphere and above the subducting slab. Thus, the Aegean mantle lithosphere seems to be 30–40 km thick, which means that its thickness increased again since the removal of the mantle lithosphere about 15 to 35 Ma ago.
Normally Speaking
Authors: Lesser Lawrence M. , Hall Randy
Published: February 2015

A cartoon ties the word normal to the concept of a distribution in statistics. Representation of data speeds prompts comparison of exponents with bases 10 and 2.
Patio Stones and Some Special Polygons
Authors: TeSelle David
Published: February 2015

Photographs of patio blocks are represented by geometric figures and prompt questions about area and symmetry.
Synthesizing Strategies Creatively: Solving Linear Equations
Authors: Ponce Gregorio A. , Tuba Imre
Published: February 2015

Line dancing is an effective—and fun!—way to convey core mathematical ideas.
Engaging with Constructive and Nonconstructive Proof
Authors: Garofalo Joe , Trinter Christine P. , Swartz Barbara A.
Published: February 2015

Logical arguments use examples and existence to prove or disprove four statements.
Developing the Vertex Formula Meaningfully
Authors: Nebesniak Amy L. , Burgoa A. Aaron
Published: February 2015

A sequenced approach to quadratics helps students develop conceptual understanding of the vertex formula.
Ways of Thinking and Mathematical Practices
Authors: Lockwood Elise , Weber Eric
Published: February 2015

The authors consider the Common Core State Standards for Mathematics (CCSSM) standards for content and practice through the lens of Harel's (2008a) Duality Principle to help empower teachers as they interpret and implement the CCSSM.
Pinterest: A Tool for Lesson Planning
Authors: Hooks Morgan
Published: February 2015

By providing its users with a vast collection of lesson plans and activities as well as the ability to collaborate with colleagues, Pinterest proves to be an asset to educators.
Math Warm-ups on a Cold Day
Authors: Hoyt David L. , Knurek Jeff
Published: February 2015

A cartoon exploring both Celsius and Fahrenheit is coupled with a full-page activity sheet.
February's Problems
Authors: Amidon Joel , Roscoe Matt
Published: February 2015

A monthly set of problems is aimed at a variety of ability levels.
Preserving Pelicans with Models That Make Sense
Authors: Moore Tamara J. , Doerr Helen M. , Glancy Aran W. , Ntow Forster D.
Published: February 2015

A model-eliciting activity is a useful tool that allows students' problem-solving skills and ideas to take flight.
Classroom-Based Formative Assessments—Guiding Teaching and Learning
Authors: Fennell Francis (SKIP) , Swartz Barbara Ann , Kobett Beth McCord , Wray Jonathan A.
Published: February 2015

Principles to Actions: Ensuring Mathematical Success for All (NCTM 2014) recognizes the need to find a way to leverage assessment opportunities to improve teaching and learning at the classroom and school level. And although we know a lot about the importance and potential impact of formative assessment done right and well (NMAP 2008; Black and Wiliam 2010), a disconnect continues to exist among planning, teaching, and assessment—and thus, between teaching and learning—in too many classrooms. Assessment must be linked to the planning and instruction of a lesson—every day—ensuring that lesson activities inform teaching and learning for all students. Principles to Actions's eighth Mathematics Teaching Practice directs teachers to “elicit and use evidence of student thinking” (NCTM 2014, p. 53, emphasis added), but what are some ways to elicit this evidence?
Jesse's train
Authors: James Julie
Published: February 2015

Fourth graders at J. C. Sommer Elemen tary School in Grove City, Ohio, were introduced to a new mathematical tool. By exploring Cuisenaire® Rods, they were able to apply relationships that they noticed to the Jesse's Train problem.
The Geometry of Scoliosis
Authors: Kurz Terri L. , Yanik H. Bahadir , Lee Mi Yeon
Published: February 2015

Scoliosis, the curvature of the spine, is a medical condition that often affects youth. This article provides students with an opportunity to explore the geometry behind the spine's curvature. Students will first develop a method for measuring curvature and then compare their method to the commonly used Cobb method. Contributors to iSTEM: Integrating Science Technology Engineering in Mathematic share ideas and activities that stimulate student interest in the integrated fields of science, technology, engineering, and mathematics (STEM) in K–grade 6 classrooms.
A central italian Coin with Dionysus/ Panther types from Cabrera de Mar (El Maresme, Barcelona), and contacts between central Italy, Hispania Citerior and Hispania Ulterior, in the 2nd and 1st centuries BC
Authors: Stannard Clive , G. Sinner Alejandro
Published: February 2015

Three “Dionysus / panther” coins are known from Catalonia, one from excavations at Cabrera de Mar (Ilturo). This is a key component of the Central Italian Assemblage of the Italo-Baetican series, and dates to the late 90s/early 80s bc. The excavation coin probably arrived during the Sertorian wars (80–72), certainly before 50. We therefore review evidence of contacts between Hispania Citerior and Central Italy, Hispania Citerior and Ulterior, and Hispania Ulterior and Central Italy. We compare coins from the Cabrera de Mar valley with Spanish coins from Minturnae. We reconsider the Isla Pedrosa wreck, which contained specimens of the Central Italian Assemblage, imported Italic ceramics from the Catalan coast and La Loba mine, and some of the more important wrecks between c. 200 and 50. There is little evidence for maritime contact between Citerior and Ulterior, but better evidence, in each case, of contacts with central Italy.
Les scènes de sacrifice sur les stèles du tophet de Sousse
Authors: Ben Amid Lamia
Published: February 2015

Le tophet de Sousse, l’antique Hadrumetum a fournit un lot de stèles datable du début de l’ère chrétienne qui porte un décor spécifique nettement romanisé. Le nombre réduit de ces monuments ne suffit pas de les ranger parmi les stèles saturniennes. Is peuvent, au plus, être considéré comme un indice marquant le début du processus de romanisation du culte de Baal Hammon dans ce vieux comptoir phénicien.
Novedades en torno al núcleo rupestre levantino de la Sierra de Albarracín. El abrigo de Prao Medias (Tormón, Teruel)
Authors: Bea Martínez Manuel
Published: February 2015

Nuevo abrigo con pinturas.
Hueso, asta y marfil: manufactura de artefactos durante el III milenio a.C. en el poblado de Los Castillejos (Montefrío, Granada)
Authors: Altamirano García Manuel
Published: February 2015

En el presente trabajo se exponen los resultados del estudio de los artefactos manufacturados en hueso, asta y marfil procedentes de los depósitos del III milenio A.C. del poblado de Los Castillejos, hasta ahora prácticamente inéditos. Se ha llevado a cabo su análisis formal, determinación de la materia prima y una minuciosa observación microscópica de la superficie de estos elementos para conocer cómo fue su proceso de manufactura. De manera indirecta, se ha obtenido, además, un gran volumen de información social, económica y cultural.
Genomic mosaicism with increased amyloid precursor protein (APP) gene copy number in single neurons from sporadic Alzheimer's disease brains
Authors: Bushman Diane M , Kaeser Gwendolyn E , Siddoway Benjamin , Westra Jurgen W , Rivera Richard R , Rehen Stevens K , Yung Yun C , Chun Jerold
Published: February 2015

Previous reports have shown that individual neurons of the brain can display somatic genomic mosaicism of unknown function. In this study, we report altered genomic mosaicism in single, sporadic Alzheimer's disease (AD) neurons characterized by increases in DNA content and amyloid precursor protein (APP) gene copy number. AD cortical nuclei displayed large variability with average DNA content increases of ∼8% over non-diseased controls that were unrelated to trisomy 21. Two independent single-cell copy number analyses identified amplifications at the APP locus. The use of single-cell qPCR identified up to 12 copies of APP in sampled neurons. Peptide nucleic acid (PNA) probes targeting APP, combined with super-resolution microscopy detected primarily single fluorescent signals of variable intensity that paralleled single-cell qPCR analyses. These data identify somatic genomic changes in single neurons, affecting known and unknown loci, which are increased in sporadic AD, and further indicate functionality for genomic mosaicism in the CNS.
Generic along‐strike segmentation of Afar normal faults, East Africa: Implications on fault growth and stress heterogeneity on seismogenic fault planes
Authors: Manighetti I. , Caulet C. , De Barros L. , Perrin C. , Cappa F. , Gaudemer Y.
Published: February 2015

Understanding how natural faults are segmented along their length can provide useful insights into fault growth processes, stress distribution on fault planes, and earthquake dynamics. We use cumulative displacement profiles to analyze the two largest scales of segmentation of ∼900 normal faults in Afar, East Africa. We build upon a prior study by Manighetti et al. (2009) and develop a new signal processing method aimed at recovering the number, position, displacement, and length of both the major (i.e., longest) and the subordinate, secondary segments within the faults. Regardless of their length, age, geographic location, total displacement, and slip rate, 90% of the faults contain two to five major segments, whereas more than 70% of these major segments are divided into two to four secondary segments. In each hierarchical rank of fault segmentation, most segments have a similar proportional length, whereas the number of segments slightly decreases with fault structural maturity. The along‐strike segmentation of the Afar faults is thus generic at its two largest scales. We summarize published fault segment data on 42 normal, reverse, and strike‐slip faults worldwide, and find a similar number (two to five) of major and secondary segments across the population. We suggest a fault growth scenario that might account for the generic large‐scale segmentation of faults. The observation of a generic segmentation suggests that seismogenic fault planes are punctuated with a deterministic number of large stress concentrations, which are likely to control the initiation, arrest and hence extent and magnitude of earthquake ruptures.
Multiscale study of electron energization during unsteady reconnection events
Authors: Ashour‐Abdalla Maha , Lapenta Giovanni , Walker Raymond J. , El‐Alaoui Mostafa , Liang Haoming
Published: February 2015

Understanding particle acceleration in the magnetotail during substorms requires knowledge of changes in the global magnetospheric configuration and the local regions of intense fields and microinstabilities caused by processes associated with reconnection. We simulated a substorm on 15 February 2008 by coupling the University of California, Los Angeles global magnetohydrodynamic simulation code and a two‐dimensional version of the iPIC3D implicit particle‐in‐cell code. The MHD code provides realistic initial and boundary conditions for the particle‐in‐cell (PIC) code, while the PIC code models the reconnection and evolution of the dipolarization front (DF) self‐consistently with full kinetic physics. In the PIC simulation, after a few seconds, an active X point forms and DF‐like structures form about every 2 s and propagate earthward. In the near‐Earth tail, the earthward moving fronts combine to form thicker structures. The presence of the macroscopic‐scale magnetic field, featuring a significant dipolar component nearer the Earth, affects the reconnection process, chocking the flow that cannot freely propagate earthward, causing the production of multiple repeating DFs. In the region away from the equator and equatorward of the separatrices, the DFs become associated with a series of spatial stripes that are visible in the electron temperature and the magnetic and electric fields and are also caused by the unsteady nature of the process of reconnection. The electrons are preferentially accelerated in the dipolarization region in the extension of the dipolarization field lines to high latitudes and reach energies of 100 keV or more. A streaming instability may be responsible for the parallel acceleration. This acceleration of the plasma associated with the DFs is greater than that occurring near the X point for this substorm.
Total electron content in the Martian atmosphere: A critical assessment of the Mars Express MARSIS data sets
Authors: Sánchez‐Cano B. , Morgan D. D. , Witasse O. , Radicella S. M. , Herraiz M. , Orosei R. , Cartacci M. , Cicchetti A. , Noschese R. , Kofman W. , Grima C. , Mouginot J. , Gurnett D. A. , Lester M. , Blelly P.‐L. , Opgenoorth H. , Quinsac G.
Published: February 2015

The total electron content (TEC) is one of the most useful parameters to evaluate the behavior of the Martian ionosphere because it contains information on the total amount of free electrons, the main component of the Martian ionospheric plasma. The Mars Express Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) radar is able to derive TEC from both of its operation modes: (1) the active ionospheric sounding (AIS) mode and (2) the subsurface mode. TEC estimates from the subsurface sounding mode can be computed from the same raw data independently using different algorithms, which should yield similar results. Significant differences on the dayside, however, have been found from two of the algorithms. Moreover, both algorithms seem also to disagree with the TEC results from the AIS mode. This paper gives a critical, quantitative, and independent assessment of these discrepancies and indicates the possible uncertainty of these databases. In addition, a comparison between the results given by the empirical model of the Martian ionosphere developed by Sánchez‐Cano et al. (2013) and the different data sets has been performed. The main result is that for solar zenith angles higher than 75°, where the maximum plasma frequency is typically small compared with the radar frequencies, the two subsurface algorithms can be confidently used. For solar zenith angles less than 75°, where the maximum plasma frequency is very close to the radar frequencies, both algorithms suffer limitations. Nevertheless, despite the solar zenith angle restrictions, the dayside TEC of one of the two algorithms is consistent with the modeled TEC.
Effect of glacial drainage water on the CO2 system and ocean acidification state in an Arctic tidewater‐glacier fjord during two contrasting years
Authors: Fransson Agneta , Chierici Melissa , Nomura Daiki , Granskog Mats A. , Kristiansen Svein , Martma Tõnu , Nehrke Gernot
Published: February 2015

In order to investigate the effect of glacial water on the CO2 system in the fjord, we studied the variability of the total alkalinity (AT), total dissolved inorganic carbon (CT), dissolved inorganic nutrients, oxygen isotopic ratio (δ18O), and freshwater fractions from the glacier front to the outer Tempelfjorden on Spitsbergen in winter 2012 (January, March, and April) and 2013 (April) and summer/fall 2013 (September). The two contrasting years clearly showed that the influence of freshwater, mixing, and haline convection affected the chemical and physical characteristics of the fjord. The seasonal variability showed the lowest calcium carbonate saturation state (Ω) and pH values in March 2012 coinciding with the highest freshwater fractions. The highest Ω and pH were found in September 2013, mostly due to CO2 uptake during primary production. Overall, we found that increased freshwater supply decreased Ω, pH, and AT. On the other hand, we observed higher AT relative to salinity in the freshwater end‐member in the mild and rainy winter of 2012 (1142 μmol kg−1) compared to AT in 2013 (526 μmol kg−1). Observations of calcite and dolomite crystals in the glacial ice suggested supply of carbonate‐rich glacial drainage water to the fjord. This implies that winters with a large amount of glacial drainage water partly provide a lessening of further ocean acidification, which will also affect the air‐sea CO2 exchange.
Projection of Indian summer monsoon climate in 2041–2060 by multiregional and global climate models
Authors: Niu Xiaorui , Wang Shuyu , Tang Jianping , Lee Dong‐Kyou , Gutowski William , Dairaku Koji , McGregor John , Katzfey Jack , Gao Xuejie , Wu Jia , Hong Songyou , Wang Yuqing , Sasaki Hidetaka
Published: February 2015

Using the results from three global climate models (GCMs) and seven regional climate models (RCMs), summer monsoon climate changes during 2041–2060 over Indian Peninsula are projected based on the Intergovernmental Panel on Climate Change A1B emission scenario. For the control climate of 1981–2000, most nested RCMs can improve the temporal‐spatial distributions of temperature and precipitation over Indian Peninsula compared to the driving GCM of European Centre/Hamburg Fifth Generation (ECHAM5). Most nested RCMs produce advanced monsoon onset for control climate, which is similar to the result of driving GCM of ECHAM5. For future climate widespread summer warming is projected over Indian Peninsula by all climate models, with the Multi‐RCMs ensemble mean (MME) temperature increasing of 1°C to 2.5°C and the maximum warming center located in northern Indian Peninsula. The disagreement in precipitation changes projected by RCMs indicates that the surface climate change on regional scale is not only dominated by the large‐scale forcing which is provided by driving GCM but also sensitive to RCM' internal physics. Overall, wetter condition is shown in MME with significant increase of monsoon rainfall over southern India, with intermodel spread ranging from −8.9% to 14.8%. Driven by same GCM, most RCMs project advanced monsoon onset while delayed onset is found in two Regional Climate Model (RegCM3) projections, indicating uncertainty can be expected in the Indian Summer Monsoon onset. All climate models except Conformal‐Cubic Atmospheric Model with equal resolution (referred as CCAMP) and two RegCM3 models project stronger summer monsoon during 2041–2060.
Adaptive stabilization of neutral systems with nonlinear perturbations and mixed time‐varying delays
Authors: Tahoun A. H.
Published: February 2015

This paper addresses the stabilization problem of neutral systems. The neutral systems assumed to be subjected to nonlinear perturbations and mixed time‐varying delays. Specifically, the adaptive control method is used to stabilize the unknown neutral systems. If the system states and the delayed states with its derivatives are available for measurement, a new and less conservative adaptive control algorithm is proposed, and sufficient conditions for the existence of the adaptive control are derived based on Lyapunov's stability theory. The main idea is to make all the stability conditions of the system depend on desired arbitrary matrices, not on the given system matrices. This is accomplished by the adaptation process. Illustrative examples with numerical simulations are studied. The simulation results show the effectiveness of the proposed design methods. Copyright © 2015 John Wiley & Sons, Ltd.
Stretchable Self‐Powered Fiber‐Based Strain Sensor
Authors: Zhong Junwen , Zhong Qize , Hu Qiyi , Wu Nan , Li Wenbo , Wang Bo , Hu Bin , Zhou Jun
Published: February 2015

The rapid development of electrical skin and wearable electronics raises the requirement of stretchable strain sensors. In this study, an active fiber‐based strain sensor (AFSS) is fabricated by coiling a fiber‐based generator around a stretchable silicone fiber. The AFSS shows the sensitive and stable performance and has the ability to detect the strain up to 25%, which is also demonstrated to detect finger motion states. It may play an essential role in future self‐powered sensor system.
Asymmetric Synthesis of Spirocyclic Oxindole‐Fused Tetrahydrothiophenes via N,N′‐Dioxide–Nickel(II) Catalyzed Domino Reaction of 1,4‐Dithiane‐2,5‐diol with 3‐Alkenyloxindoles
Authors: Zhou Pengfei , Cai Yunfei , Lin Lili , Lian Xiangjin , Xia Yong , Liu Xiaohua , Feng Xiaoming
Published: February 2015

A highly efficient chiral N,N′‐dioxide–nickel(II) complex system has been developed to catalyze the domino thia‐Michael/aldol reaction of 1,4‐dithiane‐2,5‐diol with 3‐alkenyloxindoles. A series of the desired spirocyclic oxindole‐fused tetrahydrothiophenes was obtained in good yields with excellent ee and dr (up to 97% yield, 98% ee, >19:1 dr). Besides, based on the X‐ray crystal structure of the catalyst as well as the absolute configuration of the product, a catalytic model was proposed to explain the stereocontrol process.

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[Ag21{S2P(OiPr)2}12]+: An Eight‐Electron Superatom
Authors: Dhayal Rajendra S. , Liao Jian‐Hong , Liu Yu‐Chiao , Chiang Ming‐His , Kahlal Samia , Saillard Jean‐Yves , Liu C. W.
Published: February 2015

A novel discrete [Ag21{S2P(OiPr)2}12](PF6) nanocluster has been synthesized and characterized by single‐crystal X‐ray diffraction and also NMR spectroscopy (1H, 31P), ESI mass spectrometry, and other analytic techniques (XPS, EDS, UV/Vis spectroscopy). The Ag21 skeleton has an unprecedented silver‐centered icosahedron that is capped by eight additional metal atoms. The whole framework is protected by twelve dithiophosphate ligands. According to the spherical Jellium model, the stability of monocationic nanocluster can be described by an 8‐electron superatom with 1S2 1P6 configuration, as confirmed by DFT calculations.
Self‐Sustained Cycle of Hydrolysis and Etching at Solution/Solid Interfaces: A General Strategy To Prepare Metal Oxide Micro‐/Nanostructured Arrays for High‐Performance Electrodes
Authors: Zhang Yingmeng , Zhang Weixin , Yang Zeheng , Gu Heyun , Zhu Qing , Yang Shihe , Li Mei
Published: February 2015

Assembling micro‐/nanostructured arrays on conducting substrates allows the integration of multiple functionalities into modern electronic devices. Herein, a novel self‐sustained cycle of hydrolysis and etching (SCHE) is exploited to selectively synthesize an extensive series of metal oxide micro‐/nanostructured arrays on a wide range of metal substrates, establishing the generality and efficacy of the strategy. To demonstrate the potential application of this method, the as‐prepared NiO porous nanobelt array was directly used as the anode for lithium‐ion batteries, exhibiting excellent capacity and rate capability. Conclusively, the SCHE strategy offers a systematic approach to design metal oxide micro‐/nanostructured arrays on metal substrates, which are valuable not only for lithium‐ion batteries but also for other energy conversion and storage systems and electronic devices at large.
Cooperative Catalysis: Enantioselective Propargylic Alkylation of Propargylic Alcohols with Enecarbamates Using Ruthenium/Phosphoramide Hybrid Catalysts
Authors: Senda Yasushi , Nakajima Kazunari , Nishibayashi Yoshiaki
Published: February 2015

The diastereo‐ and enantioselective propargylic alkylation of propargylic alcohols with E‐enecarbamates in the presence of a catalytic amount of thiolate‐bridged diruthenium complexes bearing an optically active phosphoramide moiety gives the corresponding propargylic alkylated products (up to 97 % ee).
Diskrete Magnesiumhydrid‐Aggregate: ein kationischer Mg13H18‐Cluster, stabilisiert durch einen NNNN‐Makrocyclus
Authors: Martin Daniel , Beckerle Klaus , Schnitzler Silvia , Spaniol Thomas P. , Maron Laurent , Okuda Jun
Published: February 2015

Große Magnesiumhydrid‐Aggregate [Mg13(Me3TACD)6(μ2‐H12)(μ3‐H6)][A]2 ((Me3TACD)H=1,4,7‐Trimethyl‐1,4,7,10‐tetraazacyclododecan; A=AlEt4, AlnBu4, B{3,5‐(CF3)2C6H3}4) wurden schrittweise aus Alkylkomplexen [Mg2(Me3TACD)R3] (R=Et, nBu) und Phenylsilan in Gegenwart von zusätzlichen MgII‐Ionen synthetisiert. Das zentrale Magnesiumatom ist wie in festem α‐MgH2 vom Rutil‐Typ oktaedrisch von sechs Hydriden koordiniert. Weitere Koordination zu sechs Magnesiumatomen führt zu einer Unterstruktur mit sieben eckenverknüpften Oktaedern, ähnlich einer hexagonalen Schicht von Brucit (Mg(OH)2). Durch Protonolyse in Gegenwart von 1,2‐Dimethoxyethan (DME) wurde dieser Cluster zu dem vierkernigen Dikation [Mg2(Me3TACD)(μ‐H)2(DME)]2[A]2 abgebaut.
Sunlight‐Driven Formation and Dissociation of a Dynamic Mixed‐Valence Thallium(III)/Thallium(I) Porphyrin Complex
Authors: Ndoyom Victoria , Fusaro Luca , Dorcet Vincent , Boitrel Bernard , Le Gac Stéphane
Published: February 2015

Inspired by a Newton’s cradle device and interested in the development of redox‐controllable bimetallic molecular switches, a mixed‐valence thallium(III)/thallium(I) bis‐strap porphyrin complex, with TlIII bound out of the plane of the N core and TlI hung to a strap on the opposite side, was formed by the addition of TlOAc to the free base and exposure to indirect sunlight. In this process, oxygen photosensitization by the porphyrin allows the oxidation of TlI to TlIII. The bimetallic complex is dynamic as the metals exchange their positions symmetrically to the porphyrin plane with TlIII funneling through the macrocycle. Further exposure of the complex to direct sunlight leads to thallium dissociation and to total recovery of the free base. Hence, the porphyrin plays a key role at all stages of the cycle of the complex: It hosts two metal ions, and by absorbing light, it allows the formation and dissociation of TlIII. These results constitute the basis for the further design of innovative light‐driven bimetallic molecular devices.
Ein hochgradig stabilisierendes Silber(I)‐vermitteltes Basenpaar in paralleler DNA
Authors: Sinha Indranil , Fonseca Guerra Célia , Müller Jens
Published: February 2015

Erstmals wurde eine parallele DNA‐Doppelhelix mit Hoogsteen‐Basenpaarung erzeugt, die bereitwillig ein Ag+‐Ion in ein internes Fehlpaar unter Bildung eines metallvermittelten Basenpaares aufnimmt. Hierzu wurde das hochgradig stabilisierende6 FP‐Ag+‐6 FP‐Basenpaar entwickelt, das die künstliche Nucleobase 6‐Furylpurin (6 FP) enthält. Eine Kombination aus temperaturabhängiger UV‐Spektroskopie, CD‐Spektroskopie und DFT‐Rechnungen wurde angewendet, um die Bildung dieses Basenpaares zu bestätigen. Die Nucleobase6 FPkann metallvermittelte Basenpaare sowohl über die Watson‐Crick‐Seite (d. h. in regulärer antiparalleler DNA) als auch über die Hoogsteen‐Seite (d. h. in paralleler DNA) bilden, abhängig von der Oligonucleotidsequenz und den experimentellen Bedingungen. Bei dem6 FP‐Ag+‐6 FP‐Basenpaar in paralleler DNA handelt es sich um das am stärksten stabilisierende Ag+‐vermittelte Basenpaar in einer Nucleinsäure, über das bisher berichtet wurde, mit einem Anstieg der Schmelztemperatur um fast 15 °C beim Binden eines Ag+‐Ions.
A Facile Synthetic Route to a New SHG Material with Two Types of Parallel π‐Conjugated Planar Triangular Units
Authors: Song Jun‐Ling , Hu Chun‐Li , Xu Xiang , Kong Fang , Mao Jiang‐Gao
Published: February 2015

A new SHG material, namely, Pb2(BO3)(NO3), which contains parallel π‐conjugated nitrate and borate anions, was obtained through a facile hydrothermal reaction by using Pb(NO3)2 and Mg(BO2)2⋅H2O as starting materials. Its structure contains honeycomb [Pb2(BO3)]∞ layers with noncoordination [NO3]− anions located at the interlayer space. Pb2(BO3)(NO3) shows a remarkable strong SHG response of approximately 9.0 times that of potassium dihydrogen phosphate (KDP) and the material is also phase‐matchable. The large SHG coefficient of Pb2(BO3)(NO3) arises from the synergistic effect of the stereoactive lone pairs on Pb2+ cations and parallel alignment of π‐conjugated BO3 and NO3 units. Based on its unique properties, Pb2(BO3)(NO3) may have great potential as a high performance NLO material in photonic applications.
Controlling the Selective Formation of Calcium Sulfate Polymorphs at Room Temperature
Authors: Tritschler Ulrich , Van Driessche Alexander E. S. , Kempter Andreas , Kellermeier Matthias , Cölfen Helmut
Published: February 2015

Calcium sulfate is a naturally abundant and technologically important mineral with a broad scope of applications. However, controlling CaSO4 polymorphism and, with it, its final material properties still represents a major challenge, and to date there is no universal method for the selective production of the different hydrated and anhydrous forms under mild conditions. Herein we report the first successful synthesis of pure anhydrite from solution at room temperature. We precipitated calcium sulfate in alcoholic media at low water contents. Moreover, by adjusting the amount of water in the syntheses, we can switch between the distinct polymorphs and fine‐tune the outcome of the reaction, yielding either any desired CaSO4 phase in pure state or binary mixtures with predefined compositions. This concept provides full control over phase selection in CaSO4 mineralization and may allow for the targeted fabrication of corresponding materials for use in various areas.
Highly Enantioselective Adsorption of Small Prochiral Molecules on a Chiral Intermetallic Compound
Authors: Prinz Jan , Gröning Oliver , Brune Harald , Widmer Roland
Published: February 2015

Intrinsically chiral surfaces of intermetallic compounds are shown to be novel materials for enantioselective processes. Their advantage is the significantly higher thermal and chemical stability, and therefore their extended application range for catalyzed chiral reactions compared to surfaces templated with chiral molecular modifiers or auxiliaries. On the Pd1‐terminated PdGa(111) surface, room‐temperature adsorption of a small prochiral molecule (9‐ethynylphenanthrene) leads to exceptionally high enantiomeric excess ratios of up to 98 %. Our findings highlight the great potential of intrinsically chiral intermetallic compounds for the development of novel, enantioselective catalysts that can be operated at high temperatures and potentially also in harsh chemical environments.
Selective and Potent Proteomimetic Inhibitors of Intracellular Protein–Protein Interactions
Authors: Barnard Anna , Long Kérya , Martin Heather L. , Miles Jennifer A. , Edwards Thomas A. , Tomlinson Darren C. , Macdonald Andrew , Wilson Andrew J.
Published: February 2015

Inhibition of protein–protein interactions (PPIs) represents a major challenge in chemical biology and drug discovery. α‐Helix mediated PPIs may be amenable to modulation using generic chemotypes, termed “proteomimetics”, which can be assembled in a modular manner to reproduce the vectoral presentation of key side chains found on a helical motif from one partner within the PPI. In this work, it is demonstrated that by using a library of N‐alkylated aromatic oligoamide helix mimetics, potent helix mimetics which reproduce their biophysical binding selectivity in a cellular context can be identified.
Condensed‐Phase, Halogen‐Bonded CF3I and C2F5I Adducts for Perfluoroalkylation Reactions
Authors: Sladojevich Filippo , McNeill Eric , Börgel Jonas , Zheng Shao‐Liang , Ritter Tobias
Published: February 2015

A family of practical, liquid trifluoromethylation and pentafluoroethylation reagents is described. We show how halogen bonding can be used to obtain easily handled liquid reagents from gaseous CF3I and CF3CF2I. The synthetic utility of the new reagents is exemplified by a novel direct arene trifluoromethylation reaction as well as adaptations of other perfluoroalkylation reactions.
Formal anti‐Carbopalladation Reactions of Non‐Activated Alkynes: Requirements, Mechanistic Insights, and Applications
Authors: Pawliczek Martin , Schneider Tobias F. , Maaß Christian , Stalke Dietmar , Werz Daniel B.
Published: February 2015

Formal anti‐carbopalladation reactions of CC triple bonds are uncommon, but highly useful transformations. Alkynes can be designed to give anti‐carbopalladation products. Prerequisite is the exclusion of other reaction pathways to provoke the cis–trans isomerization of the syn‐carbopalladation intermediate. Detailed mechanistic studies of this crucial step by experimental and computational means were performed. Application of an intramolecular version for the synthesis of oligocyclic compounds and substituted dibenzofurans is also described.
Development of new hybrid ultrafiltration membranes by entanglement of macromolecular PPSU‐SO3H chains: Preparation, morphologies, mechanical strength, and fouling resistant properties
Authors: Arumugham Thanigaivelan , Kaleekkal Noel Jacob , Doraiswamy Mohan
Published: February 2015

The present work focuses on the preparation of Polyphenylsulfone (PPSU) membranes with enhanced antifouling surfaces through an incorporation of sulfonated Polyphenylsulfone (PPSU‐SO3H), which acts as both, surface modifying agent and macromolecular additive. Initially, Sulfonated polyphenylsulfone (PPSU‐SO3H) was synthesized by using chlosulfonic acid via bulk modification method. The degree of sulfonation (DS, %) of PPSU‐SO3H was calculated by using NMR (nuclear magnetic resonance).The phase inversion technique was used to prepare all asymmetric membranes by allowing the PPSU‐SO3H (different wt %) to entangle with the PPSU membrane matrix. All prepared membranes were characterized by using scanning electron microscope (SEM), X‐ray diffraction analysis (XRD), contact angle analysis (CA), mechanical strength analysis, molecular weight cut off (MWCO), porosity (%), mean pore size, and BSA adsorption studies. The performance efficiency of the membranes was evaluated by using BSA protein as a model foulant in terms of permeability, rejection (SR %), Rm (hydraulic resistance), Rc (cake layer resistance), Rp (pore plugging resistance), Rr (reversible fouling), Rir (irreversible fouling), and FRR (flux recovery ratio). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41986.
Reduced percolation concentration in polypropylene/expanded graphite composites: Effect of viscosity and polypyrrole
Authors: Pionteck Jürgen , Melchor Valdez Elixana Maria , Piana Francesco , Omastová Mária , Luyt Adriaan Stephanus , Voit Brigitte
Published: February 2015

With the goal to obtain material combining electrical and thermal conductivity at low filler loadings, composites based on polypropylenes (PP) and expanded graphite (EG) have been prepared. The effects of matrix viscosity and of coating the EG particles with polypyrrole (PPy, EG/PPy = 37.5/62.5 by weight) on the EG dispersibility and formation of percolation structures have been analyzed. When increasing the EG amount from 6 to 8 wt %, the electrical conductivity of PP/EG composites increased by 7–9 orders of magnitude, independent of matrix viscosity. When EG‐PPy is added, percolation was observed between 8 and 12 wt % EG‐PPy (3 and 4.5 wt % EG) in case of PP with higher viscosity and 6 wt % EG (2.25 wt % EG) in case of PP with lower viscosity, exhibiting a strong synergistic effect of EG and PPy in the latter case. In contrast, PPy does not contribute to reduction of thermal percolation concentration. Thermal percolation is observed at 8 wt % EG in PP/EG composites, but no percolation was found in PP/EG‐PPy composites with EG‐PPy contents of up to 20 wt %, corresponding to 7.5 wt % EG. Analyzing the melt rheology it becomes clear that the contribution of PPy to the formation of a filler network is strongly dependent on the matrix viscosity. The comparison of thermal, electrical and rheological percolation reveals that PPy participates in electron transport reducing the electrical percolation but not to heat transport. Overall, we found a good correlation between electrical, thermal, and melt rheological percolation concentrations. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41994.
Non‐catalyst synthesis and thermal behaviors of three‐arm star aliphatic polycarbonates
Authors: Zhou Yu , Zhou Wanlei , Ge Jun , Chen Hongxiang , Zhuang Bo
Published: February 2015

Three‐arm star aliphatic polycarbonates (TMP‐PDTCs) were successfully synthesized via the ring‐opening polymerization of 2,2‐dimethyl trimethylene carbonate (DTC) initiated by trimethylolpropane (TMP) in the absence of catalysts. The structure of TMP‐PDTCs was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and gel permeation chromatography (GPC). The effects of reaction temperature, time, and the DTC/TMP molar feed ratio on the non‐catalyst polymerization were investigated. The thermal behaviors of TMP‐PDTCs were measured by differential scanning calorimetry (DSC). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41998.
Anwendung von UHPC als direkt befahrener Aufbeton bei der Integralisierung eines bestehenden Brückenbauwerks in Österreich
Authors: Hadl Philipp , della Pietra Regina , Hoang Kim Huy , Tue Nguyen Viet , Pilch Erwin
Published: February 2015

Ultrahochleistungsbeton (UHPC) hat dank seiner hohen Festigkeiten und hervorragender Dauerhaftigkeit großes Potenzial für die Instandsetzung und Verstärkung von bestehenden Bauwerken. Die Umsetzung bei diesem Pilotprojekt erfolgt durch den Einsatz einer dünnen UHPC‐Schicht, die eine Tragfähigkeitserhöhung bewirken und gleichzeitig die Abdichtung sowie den bituminösen Belag ersetzen soll. Gewöhnliche Schwachstellen wie undichte Stellen oder Spurrillenbildung können so auf ein Minimum reduziert werden. Neben einer Druckfestigkeit von ca. 180 MPa lässt sich mit dem für das Pilotprojekt entwickelten Beton ein Gefälle von bis zu 4.5 % realisieren. Insgesamt wurden bei diesem Pilotprojekt über 40 m3 UHPC in einem gewöhnlichen Transportbetonwerk hergestellt und als Ortbeton auf der Baustelle eingebaut. Mit der Umsetzung dieses Pilotprojekts in Österreich konnte die Praxistauglichkeit der Verstärkungsmethode mit UHPC erprobt werden.

Application of UHPC as road bridge topping within the adaptation of an existing conventional bridge to an integral abutment bridge in Austria

Ultra‐high performance concrete (UHPC) has a high potential for the repair and retrofitting of existing reinforced concrete structures. A thin UHPC layer of a few centimeters can replace the waterproofing as well as the asphalt pavement and increase the load‐carrying capacity. Due to its excellent durability properties, a longer service life of bridge decks made of UHPC can be expected. This paper presents the application of UHPC in the renovation of an existing reinforced concrete motorway bridge in Austria. The development of a UHPC with a compressive strength of 180 MPa, which enables a superstructure with a cross slope up to 4.5 % was necessary for this pilot project. In total, more than 40 m3 UHPC were produced in a ready‐mix concrete plant and cast on site. Within this project a successful transfer of laboratory findings into practical productions under on‐site conditions was achieved.
Do cytokinins function as two‐way signals between plants and animals?
Authors: Robischon Marcel
Published: February 2015

Cytokinins are plant hormones that have, among many other functions, senescence‐modulatory effects in plant tissue. This is evident not only from biochemical data, but is vividly illustrated in the “green island” phenotype in plant leaves caused by cytokinins released for example by leaf mining insects or microbial pathogens. It is beyond doubt that, in addition to their roles in plants, cytokinins also provoke physiological and developmental effects in animals. It is hypothesized that the recently much discussed modification of plant metabolism by insects and associated microbes via cytokinin signals has a counterpart in direct cytokinin signalling that interferes with the animals’ hormonal systems and impacts their population dynamics.
Isolation of dextran‐hydrolyzing intestinal bacteria and characterization of their dextranolytic activities
Authors: Kim Jin Kyoung , Shin So‐Yeon , Moon Jin Seok , Li Ling , Cho Seung Kee , Kim Tae‐Jip , Han Nam Soo
Published: February 2015

The aim of this study was to isolate dextran‐hydrolyzing bacteria from the human intestines and to identify their dextranolytic enzymes. For this, dextranase‐producing microorganisms were screened from fecal samples by using blue dextran‐containing media. Colonies producing a decolorized zone were isolated and they were grouped using RAPD‐PCR. 16S rRNA gene sequencing analysis revealed the isolates were Bacteroides (B.) thetaiotaomicron, B. ovatus, B. vulgatus, B. dorei, B. xylanisolvens, B. uniformis, and Veillonella (V.) rogosae. Thin layer chromatography analysis showed that the dextranases exhibit mainly endo‐type activity and produce various oligosaccharides including isomaltose and isomaltotriose. Zymogram analysis demonstrated that enzymes localized mainly in the cell membrane fraction and the molecular weight was 50–70 kDa. When cultured in a dextran‐containing medium, all strains isolated in this study produced short‐chain fatty acids, with butyric acid as the major compound. This is the first study to report that human intestinal B. xylanisolvens, B. dorei, and V. rogosae metabolize dextran utilizing dextranolytic enzymes. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 321–327, 2015.
Stacking geometry for non‐canonical G:U wobble base pair containing dinucleotide sequences in RNA: dispersion‐corrected DFT‐D study
Authors: Mondal Manas , Mukherjee Sanchita , Halder Sukanya , Bhattacharyya Dhananjay
Published: February 2015

Emergence of thousands of crystal structures of noncoding RNA molecules indicates its structural and functional diversity. RNA function is based upon a large variety of structural elements which are specifically assembled in the folded molecules. Along with the canonical Watson‐Crick base pairs, different orientations of the bases to form hydrogen‐bonded non‐canonical base pairs have also been observed in the available RNA structures. Frequencies of occurrences of different non‐canonical base pairs in RNA indicate their important role to maintain overall structure and functions of RNA. There are several reports on geometry and energetic stabilities of these non‐canonical base pairs. However, their stacking geometry and stacking stability with the neighboring base pairs are not well studied. Among the different non‐canonical base pairs, the G:U wobble base pair (G:U W:WC) is most frequently observed in the RNA double helices. Using quantum chemical method and available experimental data set we have studied the stacking geometry of G:U W:WC base pair containing dinucleotide sequences in roll‐slide parameters hyperspace for different values of twist. This study indicates that the G:U W:WC base pair can stack well with the canonical base pairs giving rise to large interaction energy. The overall preferred stacking geometry in terms of roll, twist and slide for the eleven possible dinucleotide sequences is seen to be quite dependent on their sequences. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 328–338, 2015.
d‐amino carboxamide‐based recruitment of dinitrophenol antibodies to bacterial surfaces via peptidoglycan remodeling
Authors: Fura Jonathan M. , Pires Marcos M.
Published: February 2015

During the past few decades there has been a rapid emergence of multidrug resistant bacteria afflicting human patients. At the same time, reduced output from pharmaceutical industry in this area precipitated a sharp decrease in the approval of new antibiotics. The combination of these factors potentially compromises the ability to effectively combat bacterial infections. While traditional drug discovery efforts continue in the pursuit of small molecule agents that disrupt bacterial growth, non‐traditional efforts could serve to complement antimicrobial strategies. We recently demonstrated our ability to remodel the surface of bacterial cells using unnatural d‐amino acids displaying the antigenic dinitrophenyl (DNP) handle. These immune stimulant d‐amino acids derivatives were metabolically incorporated onto the peptidoglycan of bacteria via a promiscuous surface‐anchored transpeptidase. The covalent modification of DNP moieties onto the peptidoglycan led to the anti‐DNP antibody opsonization of the bacterial cell surface. Herein, we show that the amidation of the C‐terminus to generate DNP‐displaying d‐amino carboxamide drastically improves antibody recruitment. Antibody opsonization using the d‐amino carboxamide agent is observed at lower concentrations than the d‐amino acid counterpart. In addition, the recruitment of endogenous antibodies in pooled human serum to the DNP‐modified bacterial cell surface is demonstrated for the first time. We envision that the C‐terminus amidation of DNP‐conjugated d‐amino acids could potentially facilitate translation of these results to in vivo animal disease models. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 351–359, 2015.