bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nature of subslab slow velocity anomalies beneath South America
Authors: Portner Daniel Evan , Beck Susan , Zandt George , Scire Alissa 
Published: May 2017

AbstractSlow seismic velocity anomalies are commonly imaged beneath subducting slabs in tomographic studies, yet a unifying explanation for their distribution has not been agreed upon. In South America two such anomalies have been imaged associated with subduction of the Nazca Ridge in Peru and the Juan Fernández Ridge in Chile. Here we present new seismic images of the subslab slow velocity anomaly beneath Chile, which give a unique view of the nature of such anomalies. Slow seismic velocities within a large hole in the subducted Nazca slab connect with a subslab slow anomaly that appears correlated with the extent of the subducted Juan Fernández Ridge. The hole in the slab may allow the subslab material to rise into the mantle wedge, revealing the positive buoyancy of the slow material. We propose a new model for subslab slow velocity anomalies beneath the Nazca slab related to the entrainment of hot spot material.
The 2016 North Atlantic hurricane season: A season of extremes
Authors: Collins Jennifer M. , Roache David R. 
Published: May 2017

AbstractThe 2016 North Atlantic hurricane season had an early start with a rare and powerful storm for January impacting the Azores at hurricane force. Likewise, the end of season heralded Otto which was record breaking in location and intensity being a high‐end Category 2 storm at landfall over southern central America in late November. We show that high precipitable water, positive relative vorticity, and low sea level pressure allowed for conducive conditions. During the season, few storms occurred in the main development region. While some environmental conditions were conducive for formation there (such as precipitable water, relative vorticity, and shear), the midlevel relative humidity was too low there for most of the season, presenting very dry conditions in that level of the atmosphere. We further find that the October peak in the accumulated cyclone energy was related to environmentally conducive conditions with positive relative humidity, precipitable water, relative humidity, and low values of sea level pressure. Overall 2016 was notable for a series of extremes, some rarely, and a few never before observed in the Atlantic basin, a potential harbinger of seasons to come in the face of ongoing global climate change.
Unraveling anthropogenic influence on the changing risk of heat waves in China
Authors: Sun Qiaohong , Miao Chiyuan , AghaKouchak Amir , Duan Qingyun 
Published: May 2017

AbstractHeat waves trigger substantial social and environmental impacts and even cause massive civilian casualties in extreme cases. Observations show the areas affected by heat waves have increased over China, with the most extreme heat wave occurring during the past five decades. Here we show that both trends can be attributed to anthropogenic influences. We report that under the moderate Representative Concentration Pathways 4.5 scenario, anthropogenic influences will increase the risk of occurrence of the observed maximum Heat Wave Magnitude Index in the late 21st century and will cause a more than tenfold increase in the likelihood of the strongest events on record recurring across more than half China. More than 50% of land area in China is projected to be affected by intense heat waves. Our results show that over eastern China, the extremes in heat distribution are more sensitive to precipitation deficits, indicating stronger heat wave amplification trends to occur under drier conditions. The likelihood of concurrent droughts and heat waves is expected to increase in large parts of China in the late 21st century.
Pacific sea surface temperatures, midlatitude atmospheric circulation, and widespread interannual anomalies in western U.S. streamflow
Authors: Malevich S. B. , Woodhouse C. A. 
Published: May 2017

AbstractWidespread droughts can have considerable impact on western United States (U.S.) streamflow but causes related to moisture delivery processes are not yet fully understood. Here we examine western U.S. streamflow records to identify robust leading modes of interannual variability and their links to patterns of ocean and atmospheric circulation. The leading mode of streamflow variability, a pattern of west‐wide streamflow anomalies, accounts for approximately 50% of variability and is associated with persistent high‐pressure anomalies related to ridges off the Pacific North American coast. The second mode of variability accounts for approximately 25% of variability and is associated with ocean and atmospheric conditions in the tropical Pacific. Our results suggest that the leading mode of streamflow variability in the western U.S. is more strongly associated with internally driven midlatitude atmospheric variability than equatorial Pacific sea surface temperatures.
Impacts of surface boundary conditions on regional climate model simulations of European climate during the Last Glacial Maximum
Authors: Ludwig Patrick , Pinto Joaquim G. , Raible Christoph C. , Shao Yaping 
Published: May 2017

AbstractWe examine the influences of North Atlantic sea surface temperatures (SSTs) and vegetation on regional climate simulations over Europe during the Last Glacial Maximum (LGM). Simulated regional temperature and precipitation patterns over Europe are considerably improved when using revised SSTs based on proxy data. Likewise, the simulated permafrost is more accurately reproduced with the SST modifications. These improvements are partially related to the changed regional atmospheric circulation due to the revised SSTs, leading to colder and drier conditions over Western Europe. Further sensitivity tests with prescribed vegetation for LGM conditions provide evidence of the sensitivity of the simulated glacial climate. This study reveals the importance of considering more realistic SST and vegetation boundary conditions for a more accurate representation of regional climate variability under glacial conditions.
Slip‐weakening distance and energy budget inferred from near‐fault ground deformation during the 2016 Mw7.8 Kaikōura earthquake
Authors: Kaneko Yoshihiro , Fukuyama Eiichi , Hamling Ian James 
Published: May 2017

AbstractThe 2016 M7.8 Kaikōura (New Zealand) earthquake struck the east coast of the northern South Island, resulting in strong ground shaking and large surface fault slip. Since the earthquake was well recorded by a local strong‐motion seismic network, near‐fault data may provide direct measurements of dynamic parameters associated with the fault‐weakening process. Here we estimate a proxy for slip‐weakening distance
, defined as double the fault‐parallel displacement at the time of peak ground velocity, from accelerograms recorded at a near‐fault station. Three‐component ground displacements were recovered from the double numerical integration of accelerograms, and the corresponding final displacements are validated against coseismic displacement from geodetic data. The estimated
is 4.9 m at seismic station KEKS located ∼2.7 km from a segment of the Kekerengu fault where large surface fault slip (∼12 m) has been observed. The inferred
is the largest value ever estimated from near‐fault strong motion data, yet it appears to follow the scaling of
with final slip for several large strike‐slip earthquakes. The energy budget of the M7.8 Kaikōura earthquake inferred from the scaling of
with final slip indicates that a large amount of energy was dissipated by on‐ and off‐fault inelastic deformation during the propagation of the earthquake rupture, resulting in a slower average rupture speed (
2.0 km/s).
Rabies tracing of birthdated dentate granule cells in rat temporal lobe epilepsy
Authors: Du Xi , Zhang Helen , Parent Jack M. 
Published: May 2017

ObjectiveTo understand how monosynaptic inputs onto adult‐born dentate granule cells (DGCs) are altered in experimental mesial temporal lobe epilepsy (mTLE) and whether their integration differs from early‐born DGCs that are mature at the time of epileptogenesis.MethodsA dual‐virus tracing strategy combining retroviral birthdating with rabies virus‐mediated putative retrograde trans‐synaptic tracing was used to identify and compare presynaptic inputs onto adult‐born and early‐born DGCs in the rat pilocarpine model of mTLE.ResultsOur results demonstrate that hilar ectopic DGCs preferentially synapse onto adult‐born DGCs after pilocarpine‐induced status epilepticus (SE), whereas normotopic DGCs synapse onto both adult‐born and early‐born DGCs. We also find that parvalbumin− and somatostatin− interneuron inputs are greatly diminished onto early‐born DGCs after SE. However, somatostatin− interneuron inputs onto adult‐born DGCs are maintained, likely due to preferential sprouting. Intriguingly, CA3 pyramidal cell backprojections that specifically target adult‐born DGCs arise in the epileptic brain, whereas axons of interneurons and pyramidal cells in CA1 appear to sprout across the hippocampal fissure to preferentially synapse onto early‐born DGCs.InterpretationThese data support the presence of substantial hippocampal circuit remodeling after an epileptogenic insult that generates prominent excitatory monosynaptic inputs, both local recurrent and widespread feedback loops, onto DGCs. Both adult‐born and early‐born DGCs are targets of new inputs from other DGCs as well as from CA3 and CA1 pyramidal cells after pilocarpine treatment, changes that likely contribute to epileptogenesis in experimental mTLE. Ann Neurol 2017;81:790–803
Subthalamic nucleus deep brain stimulation is neuroprotective in the A53T α‐synuclein Parkinson's disease rat model
Authors: Musacchio Thomas , Rebenstorff Maike , Fluri Felix , Brotchie Jonathan M. , Volkmann Jens , Koprich James B. , Ip Chi Wang 
Published: May 2017

ObjectiveDeep brain stimulation (DBS) of the subthalamic nucleus (STN) is a highly effective symptomatic therapy for motor deficits in Parkinson's disease (PD). An additional, disease‐modifying effect has been suspected from studies in toxin‐based PD animal models, but these models do not reflect the molecular pathology and progressive nature of PD that would be required to evaluate a disease‐modifying action. Defining a disease‐modifying effect could radically change the way in which DBS is used in PD.MethodsWe applied STN‐DBS in an adeno‐associated virus (AAV) 1/2‐driven human mutated A53T α‐synuclein (aSyn)‐overexpressing PD rat model (AAV1/2‐A53T‐aSyn). Rats were injected unilaterally, in the substantia nigra (SN), with AAV1/2‐A53T‐aSyn or control vector. Three weeks later, after behavioral and nigrostriatal dopaminergic deficits had developed, rats underwent STN‐DBS electrode implantation ipsilateral to the vector‐injected SN. Stimulation lasted for 3 weeks. Control groups remained OFF stimulation. Animals were sacrificed at 6 weeks.ResultsMotor performance in the single pellet reaching task was impaired in the AAV1/2‐A53T‐aSyn–injected stim‐OFF group, 6 weeks after AAV1/2‐A53T‐aSyn injection, compared to preoperative levels (–82%; p < 0.01). Deficits were reversed in AAV1/2‐A53T‐aSyn, stim‐ON rats after 3 weeks of active stimulation, compared to the AAV1/2‐A53T‐aSyn stim‐OFF rats (an increase of ∼400%; p < 0.05), demonstrating a beneficial effect of DBS. This motor improvement was maintained when the stimulation was turned off and was accompanied by a higher number of tyrosine hydroxylase+ SN neurons (increase of ∼29%), compared to AAV1/2‐A53T‐aSyn stim‐OFF rats (p < 0.05).InterpretationOur data support the putative neuroprotective and disease‐modifying effect of STN‐DBS in a mechanistically relevant model of PD. Ann Neurol 2017;81:825–836
Enhanced Catalytic Activity of Cobalt Porphyrin in CO2 Electroreduction upon Immobilization on Carbon Materials
Authors: Hu Xin‐Ming , Rønne Magnus H. , Pedersen Steen U. , Skrydstrup Troels , Daasbjerg Kim 
Published: May 2017

AbstractIn a comparative study of the electrocatalytic CO2 reduction, cobalt meso‐tetraphenylporphyrin (CoTPP) is used as a model molecular catalyst under both homogeneous and heterogeneous conditions. In the former case, employing N,N‐dimethylformamide as solvent, CoTPP performs poorly as an electrocatalyst giving low product selectivity in a slow reaction at a high overpotential. However, upon straightforward immobilization of CoTPP onto carbon nanotubes, a remarkable enhancement of the electrocatalytic abilities is seen with CO2 becoming selectively reduced to CO (>90 %) at a low overpotential in aqueous medium. This effect is ascribed to the particular environment created by the aqueous medium at the catalytic site of the immobilized catalyst that facilitates the adsorption and further reaction of CO2. This work highlights the significance of assessing an immobilized molecular catalyst from more than homogeneous measurements alone.
An Organic Semiconductor Organized into 3D DNA Arrays by “Bottom‐up” Rational Design
Authors: Wang Xiao , Sha Ruojie , Kristiansen Martin , Hernandez Carina , Hao Yudong , Mao Chengde , Canary James W. , Seeman Nadrian C. 
Published: May 2017

AbstractA 3D array of organic semiconductors was assembled using a DNA scaffold. An octameric aniline molecule (“octaniline”) was incorporated into a DNA building block based on a dimeric tensegrity triangle. The construct self‐assembled to form a 3D crystal. Reversible redox conversion between the pernigraniline and leucoemeraldine states of the octaniline is retained in the crystal. Protonic doping gave emeraldine salt at pH 5, corresponding to the conductive form of polyaniline. Redox cycling within the crystal was visualized by color changes and Raman microscopy. The ease of conversion between the octaniline states suggests that it is a viable electronic switch within a unique 3D structure.
Stabilizing Perovskite Structure by Interdiffusional Tailoring and Its Application in Composite Mixed Oxygen‐Ionic and Electronic Conductors
Authors: Fang Wei , Zhang Chao , Steinbach Frank , Feldhoff Armin 
Published: May 2017

AbstractPerovskite oxides have been under intense investigation as promising candidates for devices in the field of energy conversion and storage. Unfortunately, these perovskites are probably subjected to a frequent performance loss caused by phase transition. A phase‐stabilization approach via interdiffusional tailoring is identified in perovskite‐based composites. As an example, a phase‐stabilized perovskite‐fluorite composite material with both components possessing cubic symmetry was obtained by an appropriate one‐pot strategy. These findings render possible to develop a high‐performance and extremely stable dual‐phase oxygen‐transporting membrane for intermediate‐temperature air separation as well as syngas production, which also opens up numerous opportunities to overcome the phase‐transition‐induced performance degradation in other systems.
Non‐Enzymatic RNA Backbone Proofreading through Energy‐Dissipative Recycling
Authors: Mariani Angelica , Sutherland John D. 
Published: May 2017

AbstractNon‐enzymatic oligomerization of activated ribonucleotides leads to ribonucleic acids that contain a mixture of 2′,5′‐ and 3′,5′‐linkages, and overcoming this backbone heterogeneity has long been considered a major limitation to the prebiotic emergence of RNA. Herein, we demonstrate non‐enzymatic chemistry that progressively converts 2′,5′‐linkages into 3′,5′‐linkages through iterative degradation and repair. The energetic costs of this proofreading are met by the hydrolytic turnover of a phosphate activating agent and an acylating agent. With multiple rounds of this energy‐dissipative recycling, we show that all‐3′,5′‐linked duplex RNA can emerge from a backbone heterogeneous mixture, thereby delineating a route that could have driven RNA evolution on the early earth.
Effect of acetylation on the properties of microfibrillated cellulose‐LDPE composites
Authors: Lepetit Amaury , Drolet Richard , Tolnai Balázs , Zerrouki Rachida , Montplaisir Daniel 
Published: May 2017

ABSTRACTSolvent‐free acetylation of microfibrillated cellulose was carried out in order to improve their hydrophobicity. All the samples were filled with low‐density polyethylene. The morphology, mechanical properties, and water uptake of the ensuing composites were investigated. An excessive reaction time leads to degradation of the fibers, which was observed by scanning electron microscopy and fiber quality analysis. The acetylation treatment did not improve the mechanical properties of composites but extensively decreased the moisture absorption of the composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 44933.
Fiber and film developments from immiscible blends of cellulose acetate propionate and poly(butylene terephthalate)
Authors: Liang Nai‐Yun , Don Trong‐Ming , Huang Chih‐Yuan , Chiu Wen‐Yen 
Published: May 2017

ABSTRACTBinary blends of cellulose acetate propionate (CAP) and poly(butylene terephthalate) (PBT) in the composition range of 5–15 wt % for CAP were prepared in the form of films and fibers by compression molding and spinning, respectively. The presence of two invariant glass‐transition temperatures corresponding to the CAP and PBT components and viscosities lower than those of the neat PBT of the CAP–PBT blends implied that the CAP–PBT blends were immiscible. Moreover, the crystallinity of the PBT component was higher in the spun fibers than in the films; this was possibly due to the different cooling methods or the chain orientation in the spinning process. In the meantime, the CAP component could not undergo crystallization because of its rigid structure and alkyl substituents. For the CAP–PBT films, the amorphous CAP was present as dispersed particles in the PBT matrix; but it became rods in the spun fibers. In addition, the presence of the amorphous CAP resulted in a decrease in the tensile strength and an increase in the elongation at break for the CAP–PBT fibers. The CAP–PBT films and fibers could be applied in a wide range of applications requiring renewable properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45013.
Tuning the Catalytic Activity of Tertiary‐Amine Functionalized Polyacrylonitrile Fibers by Adjusting the Surface Microenvironment
Authors: Li Pengyu , Liu Yuanyuan , Cao Jian , Tao Minli , Zhang Wenqin 
Published: May 2017

AbstractPolyacrylonitrile fibers were functionalized with different amines to construct special tridimensional catalytic microenvironments at the surface. The polarity of the microenvironments at the surface of the fiber catalyst was tuned by changing the ratio of hydrophobic and hydrophilic amines. The catalytic performances of these microenvironments were examined for a cyanation reaction in water. Among these fiber catalysts with different microenvironments, the one modified with more hydrophobic benzylamine groups (PANBTF) shows much higher catalytic activity than that modified by hydrophilic ethanolamine groups. PANBTF can efficiently and rapidly catalyze the cyanation reaction of benzaldehyde and ethyl cyanoformate in water with a yield of 94 % at room temperature within 40 min. Moreover, a mechanism promoted by the hydrophobic microenvironment has been proposed to explain the high and specific catalytic activity of PANBTF. In addition, this fiber catalyst exhibited excellent recyclability and reusability (8 times) without further treatment, and it also performed well in flow‐chemistry tests and scaled‐up experiments, which indicated potential for the application of PANBTF in industrial production.
Potential of On‐Board Gasoline Upgrading for Enhancement of Engine Efficiency
Authors: Kuchling Thomas , Endisch Matthias , Schneider Jens , Kureti Sven , Hübner Walter , Preis Michael , Schmidt Christian 
Published: May 2017

AbstractApart from the introduction of renewable fuels, improved engine efficiency is a useful strategy for the reduction of CO2 emission from vehicles. Therefore, this work deals with the catalytic on‐board upgrading of commercial gasoline to enhance the content of aromatics, leading to improved knocking behavior to allow higher compression in the engine. Resulting from theoretical considerations and thermodynamic calculations, model mixtures with a higher aromatic content were prepared and analyzed towards their octane number. Engine tests with these mixtures show an enhancement of engine efficiency. Laboratory‐scale catalytic reforming experiments demonstrated a relative increase of the aromatic content in the treated gasoline. The gaseous cracking products have good knocking behavior and could be routed to the engine as additional fuel.
Application of a Wire‐Mesh Sensor for the Study of Chemical Species Conversion in a Bubble Column
Authors: Kipping Ragna , Kryk Holger , Schleicher Eckhard , Gustke Matthias , Hampel Uwe 
Published: May 2017

AbstractThe utilization of a wire‐mesh sensor for the measurement of chemical species conversion during the chemical adsorption of carbon dioxide in sodium hydroxide solution is reported for the first time. The wire‐mesh sensor obtains cross‐sectional images of the liquid‐phase conductivity, which changes with the consumption of hydroxide during the reaction. A theoretical model was applied to verify the use of conductivity as an indicator for the reaction progress. Experiments were carried out using a lab‐scale bubble column reactor with two wire‐mesh sensors at different reactor heights. The results obtained from the reactor model and experiments showed very good agreement and demonstrate the potential of this imaging instrument to follow the course of a chemical reaction via ionic species concentration even in a dense bubbly flow. This way, a better understanding of the coupling of hydrodynamics, mass transfer, and reaction in bubble columns and other reaction devices can be achieved.
Cooperative Polar/Steric Strategy in Achieving Site‐Selective Photocatalyzed C(sp3)−H Functionalization
Authors: Yamada Keiichi , Fukuyama Takahide , Fujii Saki , Ravelli Davide , Fagnoni Maurizio , Ryu Ilhyong 
Published: May 2017

AbstractSynergistic control over the SH2 transition states of hydrogen abstraction exploiting polar and steric effects provides a promising cooperative strategy for site‐selective C(sp3)−H functionalization using decatungstate anion photocatalysis. By using this photocatalytic approach, the C−H bonds of substituted lactones and cyclic ketones were functionalized selectively. In the remarkable case of 2‐isoamyl 4‐tert‐butyl cyclohexanone (1 t) bearing five methyl, five methylene, and three methine C−H bonds, one methine C−H bond in the isoamyl tether was selectively functionalized.
Luminescent probing of the simplest chiral α‐amino acid–alanine in an enantiopure and racemic state
Authors: Tarasevych Arkadii V. , Kostyukov Anton I. , Baronskiy Mark G. , Rastorguev Alexander A. , Guillemin Jean‐Claude , Snytnikov Valeriy N. 
Published: May 2017

AbstractLuminescent spectroscopy combined with the technique of luminescent probing with rare earth ions (europium, gadolinium, terbium) and an actinide ion (uranyl) was used to differentiate enantiopure and racemic alanine, the simplest chiral proteinogenic amino acid. Using the achiral luminescent probes, small differences between pure L and DL alanine in the solid state were strongly amplified. Based on the observed electronic transitions of the probes, the position of the triplet level of the coordinated alanine was estimated. Formation of homo‐ and heterochiral complexes between enantiomers of alanine and the metal ions is discussed as a possible mechanism of chiral self‐discrimination.