bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐resolution Sr/Ca ratios in a Porites lutea coral from Lakshadweep Archipelago, southeast Arabian Sea: An example from a region experiencing steady rise in the reef temperature
Authors: Sagar Netramani , Hetzinger Steffen , Pfeiffer Miriam , Masood Ahmad Syed , Dullo Wolf‐Christian , Garbe‐Schönberg Dieter 
Published: December 2015

AbstractHere we present the first record of Sr/Ca variability in a massive Porites lutea coral from the Lakshadweep Archipelago, Arabian Sea. The annual mean sea surface temperature (SST) in this region and the surrounding areas has increased steadily in the recent past. During some major El Niño events, SSTs are even higher, imposing additional thermal‐stress on corals, episodically leading to coral bleaching. We infer from the coral‐Sr/Ca record (1981–2008) that during some of these events high and persistent SSTs lead to a dampening of the temperature signal in coral‐Sr/Ca, impairing the coral's ability to record full scale warming. Thus, coral‐Sr/Ca may provide a history of past El Niño Southern‐Oscillation (ENSO) induced thermal‐stress episodes, which are a recurrent feature also seen in cross‐spectral analysis between coral‐Sr/Ca and the Nino3.4 index. Despite the impact of episodical thermal‐stress during major El Niño events, our coral proxy faithfully records the seasonal monsoon‐induced summer cooling on the order of ∼2.3°C. Calibration of coral‐Sr/Ca with instrumental grid‐SST data shows significant correlation to regional SST and monsoon variability. Hence, massive Porites corals of this region are highly valuable archives for reconstructing long‐term changes in SST, strongly influenced by monsoon variability on seasonal scales. More importantly, our data show that this site with increasing SST is an ideal location for testing the future effects of the projected anthropogenic SST increase on coral reefs that are already under thermal‐stress worldwide.
The response of the central Arctic Ocean stratification to freshwater perturbations
Authors: Pemberton P. , Nilsson J. 
Published: December 2015

AbstractUsing a state‐of‐the‐art coupled ice‐ocean‐circulation model, we perform a number of sensitivity experiments to examine how the central Arctic Ocean stratification responds to changes in river runoff and precipitation. The simulations yield marked changes in the cold halocline and the Arctic Atlantic layer. Increased precipitation yields a warming of the Atlantic layer, which primarily is an advective signal, propagated through the St. Anna Trough, reflecting air‐sea heat flux changes over the Barents Sea. As the freshwater supply is increased, the anticyclonic Beaufort Gyre is weakened and a greater proportion of the Arctic Ocean freshwater is exported via the Fram Strait, with nearly compensating export decreases through the Canadian Arctic Archipelago. The corresponding reorganization of the freshwater pool appears to be controlled by advective processes, rather than by the local changes in the surface freshwater flux. A simple conceptual model of the Arctic Ocean, based on a geostrophically controlled discharge of the low‐salinity water, is introduced and compared with the simulations. Key predictions of the conceptual model are that the halocline depth should decrease with increasing freshwater input and that the Arctic Ocean freshwater storage should increase proportionally to the square root of the freshwater input, which are in broad qualitative agreement with the sensitivity experiments. However, the model‐simulated rate of increase of the freshwater storage is weaker, indicating that effects related to wind forcing and rerouting of the freshwater‐transport pathways play an important role for the dynamics of the Arctic Ocean freshwater storage.
Do deep‐ocean kinetic energy spectra represent deterministic or stochastic signals?
Authors: van Haren Hans 
Published: December 2015

AbstractIn analogy with historic analyses of shallow‐water tide‐gauge records, in which tides and their higher harmonics are modified by sea level changes induced by atmospheric disturbances, it is shown that deep‐sea currents can be interpreted as motions at predominantly inertial‐tidal harmonic frequencies modified by slowly varying background conditions. In this interpretation, their kinetic energy spectra may not be smoothed into a quasi‐stochastic continuum for (random‐)statistic confidence. Instead, they are considered as quasi‐deterministic line‐spectra. Thus, the climatology of the internal wave field and its slowly varying background can be inferred from line spectra filling the cusps around nonlinear tidal‐inertial harmonics, as suggested previously.
The inflow of Atlantic water at the Fram Strait and its interannual variability
Authors: Kawasaki Takao , Hasumi Hiroyasu 
Published: December 2015

AbstractThe heat influx of the Atlantic water and its interannual variability through the Fram Strait toward the Arctic Ocean are examined by using a realistically configured ice‐ocean general circulation model. The modeled routes of the Atlantic water and high eddy activity around the Fram Strait are consistent with many observations. Two‐thirds of the heat transported by the Atlantic water passing through the Fram Strait (78°N) is lost by the westward transport and the sea surface cooling, and the other one‐third is injected to the Arctic Ocean. The contribution of oceanic eddy to the westward heat transport is 5% of that of mean current. The variability of sea level pressure anomaly centered at the Nordic Seas explains the interannual variability of the heat passing through the Fram Strait, transported westward, and cooled at the sea surface in the north of the Fram Strait. The interannual variabilities of these heat fluxes have significant correlations with the NAO. The interannual variability of heat transported by the Atlantic water and entering the Arctic Ocean is caused by the variability of the Siberian high.
Modeling of ice pinnacle formation on Callisto
Authors: White Oliver L. , Umurhan Orkan M. , Moore Jeffrey M. , Howard Alan D. 
Published: December 2015

AbstractCallisto's pinnacle terrain has been interpreted to form through sublimation weathering of bedrock and subsequent deposition of the sublimated ice in local cold traps on peaks and crater rims. To investigate how these processes are affected by environmental parameters, including solar illumination and the composition and concentration of ices in the crust, we employ the MARSSIM landform evolution model and advance its treatment of the physics that underlies the relevant processes. Both ice sublimation and deposition are controlled by surface temperature, which we calculate based on energy contributions from both insolation and thermal reradiation from the surrounding landscape. We perform 4.5 Gyr duration simulations whereby we separately consider and model CO2 and H2O as the crustal ice species. We find that sublimating a crustal content of 10% CO2 ice (a reasonable but arbitrarily selected value) yields present‐day landform degradation and regolith coverage that is comparable to what is observed on Callisto. In our H2O ice simulations we reproduce the essential features of pinnacle ice distribution at both the equator and midlatitudes. Our present nominal crustal H2O ice content is 33%, which produces a maximum pinnacle ice thickness of 64 m. Pinnacle height is likely limited by collapse or mass wasting of the ice once it reaches a certain thickness.
Handy Protocols using Vinyl Nosylates in Suzuki–Miyaura Cross‐Coupling Reactions
Authors: Dikova Anna , Cheval Nicolas P. , Blanc Aurélien , Weibel Jean‐Marc , Pale Patrick 
Published: December 2015

AbstractVinyl nosylates derived from 1,3‐dicarbonyl compounds could be engaged in Suzuki–Myaura cross coupling reactions with aryl‐, vinyl‐ and methylboronic acids or trifluoborate derivatives at room temperature in the presence of 2 mol% of [1,1′‐bis(diphenylphosphino)ferrocene]dichloropalladium(II) [PdCl2(dppf)]. One‐pot procedures have been set up for practical and efficient nosylation–cross‐coupling reactions. Nosylate, as a cheap novel pseudo‐halide, gives very stable compounds and is very efficient in Suzuki–Myaura cross coupling reactions (21 examples, 44–99%).magnified image
Scandium(III) Triflate‐Catalyzed anti‐Markovnikov Hydrothiolation of Functionalized Olefins
Authors: Kuciński Krzysztof , Pawluć Piotr , Hreczycho Grzegorz 
Published: December 2015

AbstractScandium(III) triflate promoted highly selective addition of thiols to functionalized olefins under mild conditions. The addition follows anti‐Markovnikov regioselectivities, which are unusual for Lewis acids‐catalyzed hydrothiolation. This reaction marks broad functional groups tolerance, which opens a beneficial synthetic route to functionalized and biologically active thio‐compounds. This method is broadly applicable and offers a simple work‐up in the green manner.magnified image
Nanodrähte in Chemo‐ und Biosensoren: aktueller Stand und Fahrplan für die Zukunft
Authors: Fennell John F. , Liu Sophie F. , Azzarelli Joseph M. , Weis Jonathan G. , Rochat Sébastien , Mirica Katherine A. , Ravnsbæk Jens B. , Swager Timothy M. 
Published: December 2015

AbstractSensoren auf Basis von chemischen Widerständen gewinnen derzeit stark an Bedeutung. Im Vergleich zu herkömmlichen Analysegeräten sind sie preisgünstig, lassen sich leicht in elektronische Bauteile integrieren und benötigen weniger Strom. Nanodrähte (NWs) spielen für die Entwicklung von Chemosensoren eine zentrale Rolle. Mit ihrer großen Oberfläche, den Übergängen zwischen den Nanodrähten und den definierten Leitungswegen gewährleisten sie eine hervorragende Sensoransprache und verfügen über neuartige Mechanismen, wie ein Bindungsereignis oder eine andere Aktion des Analyten in ein Signal weitergeleitet wird. Dieser Aufsatz erläutert den aktuellen Entwicklungsstand der NW‐Chemosensoren. Wir beginnen mit dem Prinzip der Signalübertragung in NW‐Sensoren. Anschließend erhält der Leser einen Überblick über die Leistungsparameter der Bauelemente. Dann gehen wir auf die verschiedenen NW‐Typen und die Architektur der NW‐Bauelemente ein und erläutern die unterschiedlichen Strategien zur NW‐Funktionalisierung. Zum Abschluss entwerfen wir einen Fahrplan für die weitere Entwicklung, der Selektivität, Drift und Empfindlichkeit, die Analyse der Messantwort sowie neue Anwendungen berücksichtigt.
Kupferhydrid‐katalysierte Hydroaminierung von Alkenen und Alkinen
Authors: Pirnot Michael T. , Wang Yi‐Ming , Buchwald Stephen L. 
Published: December 2015

AbstractIn den vergangenen Jahren wurde die CuH‐katalysierte Hydroaminierung entdeckt und als robuster und konzeptionell neuer Synthesezugang zu enantiomerenangereicherten sekundären und tertiären Aminen entwickelt. Der Erfolg auf diesem Gebiet wurde möglich durch zahlreiche frühere Beispiele für die Katalyse mit Kupfer(I)hydrid und die gut untersuchte Verwendung von Hydroxylaminestern als elektrophile Aminquellen in ähnlichen kupferkatalysierten Reaktionen. Dieser Kurzaufsatz beschreibt Hintergrund, Fortschritte und mechanistische Untersuchungen der CuH‐katalysierten Hydroaminierung.
Synthese kristalliner Chalkogenide in ionischen Flüssigkeiten
Authors: Santner Silke , Heine Johanna , Dehnen Stefanie 
Published: December 2015

AbstractKristalline Chalkogenide gehören zu den vielversprechendsten Materialklassen. Außer dicht gepackten Festkörperstrukturen können sie auch Arrangements molekularer Cluster und Netzwerke mit hohen Porositäten bilden, wie in den so genannten zeotypen Chalkogenidometallaten. Sie zeichnen sich durch große Strukturvielfalt und interessante physikalische Eigenschaften aus. Zusätzlich zu Halbleitereigenschaften findet man Photoleitfähigkeit, Ionenleitfähigkeit, die Möglichkeit zum Moleküleinfang sowie chemische und katalytische Aktivität. Das große Interesse an der Entwicklung neuer und maßgeschneiderter Chalkogenide führte im Laufe der Jahre zu der Suche nach immer neuen und besseren Synthesestrategien. Es lässt sich ein klarer Trend in Richtung niedrigerer Synthesetemperaturen erkennen, was auf ökonomische und ökologische Gründe sowie den Wunsch nach einer besseren Reaktionskontrolle zurückzuführen ist. So kam es auch im Bereich der Chalkogenide zu Anwendungen von ionischen Flüssigkeiten als Designermedium für die Materialsynthese. In diesem Aufsatz fassen wir jüngste Entwicklungen zusammen und geben einen Überblick über verschiedene Familien von Chalkogeniden und deren Eigenschaften.
An Electron‐Deficient Building Block Based on the B←N Unit: An Electron Acceptor for All‐Polymer Solar Cells
Authors: Dou Chuandong , Long Xiaojing , Ding Zicheng , Xie Zhiyuan , Liu Jun , Wang Lixiang 
Published: December 2015

AbstractA double B←N bridged bipyridyl (BNBP) is a novel electron‐deficient building block for polymer electron acceptors in all‐polymer solar cells. The B←N bridging units endow BNBP with fixed planar configuration and low‐lying LUMO/HOMO energy levels. As a result, the polymer based on BNBP units (P‐BNBP‐T) exhibits high electron mobility, low‐lying LUMO/HOMO energy levels, and strong absorbance in the visible region, which is desirable for polymer electron acceptors. Preliminary all‐polymer solar cell (all‐PSC) devices with P‐BNBP‐T as the electron acceptor and PTB7 as the electron donor exhibit a power conversion efficiency (PCE) of 3.38 %, which is among the highest values of all‐PSCs with PTB7 as the electron donor.
Stabile Peptide statt “gestapelte Peptide”: hochaffine αvβ6‐selektive Integrinliganden
Authors: Maltsev Oleg V. , Marelli Udaya Kiran , Kapp Tobias G. , Di Leva Francesco Saverio , Di Maro Salvatore , Nieberler Markus , Reuning Ute , Schwaiger Markus , Novellino Ettore , Marinelli Luciana , Kessler Horst 
Published: December 2015

AbstractDas Integrin αvβ6 bindet mit hoher Selektivität an das die RGD‐Sequenz enthaltende Peptid des Maul‐und‐Klauenseuche‐Virus. In dieser Arbeit wurde die lange, für die Bindung dieses Liganden wichtige Helix systematisch zu einem enzymatisch stabilen, cyclischen Peptid verkleinert, welches subnanomolare Bindungsaktivität für den αvβ6‐Rezeptor und eine bemerkenswerte Selektivität gegenüber anderen Integrinrezeptoren besitzt. Um die molekularen Grundlagen für die hohe Bindungsaffinität und Rezeptorsubtypselektivität aufzuklären, wurden Dockingexperimente durchgeführt. Des Weiteren wurde auch die Anwendbarkeit des funktionalisierten Liganden in biomedizinischen Studien gezeigt.
Dynamics of Photoelectrons and Structural Changes of Tungsten Trioxide Observed by Femtosecond Transient XAFS
Authors: Uemura Yohei , Kido Daiki , Wakisaka Yuki , Uehara Hiromitsu , Ohba Tadashi , Niwa Yasuhiro , Nozawa Shunsuke , Sato Tokushi , Ichiyanagi Kohei , Fukaya Ryo , Adachi Shin‐ichi , Katayama Tetsuo , Togashi Tadashi , Owada Sigeki , Ogawa Kanade , Yabashi Makina , Hatada Keisuke , Takakusagi Satoru , Yokoyama Toshihiko , Ohtani Bunsho , Asakura Kiyotaka 
Published: December 2015

AbstractThe dynamics of the local electronic and geometric structures of WO3 following photoexcitation were studied by femtosecond time‐resolved X‐ray absorption fine structure (XAFS) spectroscopy using an X‐ray free electron laser (XFEL). We found that the electronic state was the first to change followed by the local structure, which was affected within 200 ps of photoexcitation.
Concise Total Synthesis of Enigmazole A
Authors: Ahlers Andreas , de Haro Teresa , Gabor Barbara , Fürstner Alois 
Published: December 2015

AbstractAn efficient entry into the phosphorylated marine macrolide enigmazole A is described. Enigmazole A interferes with c‐Kit signaling by an as yet unknown mode of action and is therefore a potential lead in the quest for novel anticancer agents. Key to success is a gold‐catalyzed cascade comprising a [3,3]‐sigmatropic rearrangement of a propargyl acetate along the periphery of a macrocyclic scaffold, followed by a transannular hydroalkoxylation of the resulting transient allenyl acetate. This transformation mandated the use of a chiral gold catalyst to ensure a matching double‐asymmetric setting. Other noteworthy steps are the preparation of the oxazole building block by a palladium‐catalyzed C−H activation, as well as the smooth ring‐closing alkyne metathesis of a diyne substrate bearing a propargylic leaving group, which has only little precedent.
Stable Peptides Instead of Stapled Peptides: Highly Potent αvβ6‐Selective Integrin Ligands
Authors: Maltsev Oleg V. , Marelli Udaya Kiran , Kapp Tobias G. , Di Leva Francesco Saverio , Di Maro Salvatore , Nieberler Markus , Reuning Ute , Schwaiger Markus , Novellino Ettore , Marinelli Luciana , Kessler Horst 
Published: December 2015

AbstractThe αvβ6 integrin binds the RGD‐containing peptide of the foot and mouth disease virus with high selectivity. In this study, the long binding helix of this ligand was downsized to an enzymatically stable cyclic peptide endowed with sub‐nanomolar binding affinity toward the αvβ6 receptor and remarkable selectivity against other integrins. Computational studies were performed to disclose the molecular bases underlying the high binding affinity and receptor subtype selectivity of this peptide. Finally, the utility of the ligand for use in biomedical studies was also demonstrated here.
Vacancy‐Engineered Nanoceria: Enzyme Mimetic Hotspots for the Degradation of Nerve Agents
Authors: Vernekar Amit A. , Das Tandrila , Mugesh Govindasamy 
Published: December 2015

AbstractOrganophosphorus‐based nerve agents, such as paraoxon, parathion, and malathion, inhibit acetylcholinesterase, which results in paralysis, respiratory failure, and death. Bacteria are known to use the enzyme phosphotriesterase (PTE) to break down these compounds. In this work, we designed vacancy‐engineered nanoceria (VE CeO2 NPs) as PTE mimetic hotspots for the rapid degradation of nerve agents. We observed that the hydrolytic effect of the nanomaterial is due to the synergistic activity between both Ce3+ and Ce4+ ions located in the active site‐like hotspots. Furthermore, the catalysis by nanoceria overcomes the product inhibition generally observed for PTE and small molecule‐based PTE mimetics.
Water states and thermal processability of boric acid modified poly(vinyl alcohol)
Authors: Wang Ning , Zhao Lipeng , Zhang Chuhong , Li Li 
Published: December 2015

ABSTRACTTo further improve the processability of water plasticized poly(vinyl alcohol) (PVA), boric acid (BA), which can rapidly form reversible crosslinked structure with the hydroxyl groups of PVA, was adopted as a modifier, and the water states, thermal performance, and rheological properties of modified PVA were investigated. The results showed that ascribing to the formation of the crosslinked structure between PVA and BA, the content of nonfreezing water in system increased, indicating that the bondage of PVA matrix on water enhanced, thus retarding the tempestuous evaporation of water in system during melt process and making more water remained in system to play the role of plasticizer. Meanwhile, this crosslinked structure shielded part hydroxyl groups in PVA chains, leading to the further weakening of the self‐hydrogen bonding of PVA, and guaranteeing a lower melting point and higher decomposition temperature, thus obtaining a quite wide thermal processing window, i.e., ≥179°C. The melt viscosity of BA modified PVA slightly increased, but still satisfied the requirements for thermal processing, thus reinforcing the flow stability of the melt at high shearing rate. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43246.
Influence of curing sequence on phase structure and properties of bisphenol A‐aniline benzoxazine/N,N′‐(2,2,4‐trimethylhexane‐1,6‐diyl) bis (maleimide)/imidazole blend
Authors: Wang Zhi , Cao Ni , Miao Yu , Gu Yi 
Published: December 2015

ABSTRACTThe effects of different catalysts on the curing sequences of bisphenol A‐aniline benzoxazine (BA‐a)/N,N′‐(2,2,4‐trimethylhexane‐1,6‐diyl) bis (maleimide) (TBMI) blends were studied, and the influence of curing sequences on the phase structure and properties of products was discussed. In BA‐a/TBMI/adipic acid, BA‐a homopolymerized first, followed by the copolymerization between TBMI and ring‐opened benzoxazine. This curing sequence led to strong copolymerization, which limited the movement of components and resulted in homogeneous structures of the final products. However, in BA‐a/TBMI/imidazole, TBMI homopolymerized firstly, followed by the homopolymerization of BA‐a. BA‐a and TBMI hardly copolymerized, and the products presented phase‐separated (bi‐continuous phase) structures finally. The degree of copolymerization and phase structures of products differed due to different curing sequences when different catalysts were used. Furthermore, the product with phase‐separated structures had improved thermal property and toughness compared to those of the product with homogeneous structures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43259.
Polyurethane foams from alkaline lignin‐based polyether polyol
Authors: Li Hong‐Qiang , Shao Qiang , Luo Hao , Xu Jian 
Published: December 2015

ABSTRACTAs a byproduct produced during biorefining, alkaline lignin (AL) possesses multiple benzene ring and phenol hydroxyl groups with high chemical reactivity, and is renewable and cheaper than petrochemical products. Here, AL was liquefied in polyethylene glycol‐400/glycerol and subsequently used to prepare polyurethane foams (PUFs). The results showed that the AL could be almost completely liquefied. The resulting lignin‐based polyether polyol (LPP) exhibited physicochemical properties similar to a commercial polyether polyol (PP). The PUFs made from LPP presented better thermal stability and higher compressive strength than those PUFs obtained from commercial PP, suggesting this could be a viable commercial application for AL. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 43261.
“A red cross appeared in the sky” and other celestial signs: Presumable European aurorae in the mid AD 770s were halo displays
Authors: Neuhäuser D. L. , Neuhäuser R. 
Published: December 2015

AbstractThe interpretation of the strong 14C variation around AD 775 as one (or several) solar super‐flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A red cross /crucifix in AD 773/4/6 from the Anglo‐Saxon Chronicle, inflamed shields in AD 776 (both listed in the aurora catalogue of Link 1962), and riders on white horses in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three can be interpreted convincingly as halo displays: The red cross or crucifix is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the inflamed shields and the riders on white horses were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2013), the two other sightings have tobe dated AD 776, i.e. anyway too late for being in connection with a 14C rise that started before AD 775. We also sketch the ideological background of those sightings and there were many similar reports throughout that time. In addition, we present a small drawing of a lunar halo display with horizontal arc and vertical pillar forming a cross for shortly later, namely AD 806 June 4, the night of full moon, also from the Anglo‐Saxon Chronicle; we also show historic observations of halo phenomena (mock suns and crosses) from G. Kirch and Hevelius – and a modern photograph. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)