bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patterns of glacier ablation acrossNorth‐CentralChile: Identifying the limits of empirical melt models under sublimation‐favorable conditions
Authors: Ayala A. , Pellicciotti F. , MacDonell S. , McPhee J. , Burlando P. 
Published: June 2017

AbstractWe investigate the energy balance and ablation regimes of glaciers in high‐elevation, dry environments using glaciometeorological data collected on six glaciers in the semiarid Andes of North‐Central Chile (29–34°S, 3127–5324 m). We use a point‐scale physically based energy balance (EB) model and an enhanced Temperature‐Index (ETI) model that calculates melt rates only as a function of air temperature and net shortwave radiation. At all sites, the largest energy inputs are net shortwave and incoming longwave radiation, which are controlled by surface albedo and elevation, respectively. Turbulent fluxes cancel each other out at the lower sites, but as elevation increases, cold, dry and wind‐exposed conditions increase the magnitude of negative latent heat fluxes, associated with large surface sublimation rates. In midsummer (January), ablation rates vary from 67.9 mm w.e. d−1at the lowest site (∼100% corresponding to melt), to 2.3 mm w.e. d−1at the highest site (>85% corresponding to surface sublimation). At low‐elevation, low‐albedo, melt‐dominated sites, the ETI model correctly reproduces melt using a large range of possible parameters, but both the performance and parameter transferability decrease with elevation for two main reasons: (i) the air temperature threshold approach for melt onset does not capture the diurnal variability of melt in cold and strong irradiated environments and (ii) energy losses decrease the correlation between melt and net shortwave radiation. We summarize our results by means of an elevation profile of ablation components that can be used as reference in future studies of glacier ablation in the semiarid Andes.
Transient slab flattening beneath Colombia
Authors: Wagner L. S. , Jaramillo J. S. , Ramírez‐Hoyos L. F. , Monsalve G. , Cardona A. , Becker T. W. 
Published: June 2017

AbstractSubduction of the Nazca and Caribbean Plates beneath northwestern Colombia is seen in two distinct Wadati Benioff Zones, one associated with a flat slab to the north and one associated with normal subduction south of 5.5°N. The normal subduction region is characterized by an active arc, whereas the flat slab region has no known Holocene volcanism. We analyze volcanic patterns over the past 14 Ma to show that in the mid‐Miocene a continuous arc extended up to 7°N, indicating normal subduction of the Nazca Plate all along Colombia's Pacific margin. However, by ~6 Ma, we find a complete cessation of this arc north of 3°N, indicating the presence of a far more laterally extensive flat slab than at present. Volcanism did not resume between 3°N and 6°N until after 4 Ma, consistent with lateral tearing and resteepening of the southern portion of the Colombian flat slab at that time.
Heat flow, heat production, and crustal temperatures in the Archaean Bundelkhand craton, north‐central India: Implications for thermal regime beneath the Indian shield
Authors: Podugu Nagaraju , Ray Labani , Singh S. P. , Roy Sukanta 
Published: June 2017

AbstractHeat flow and heat production data sets constrain the crustal thermal structure in the 2.5–3.5 Ga Bundelkhand craton, the oldest cratonic core in northern Indian shield, for the first time and allow comparisons with the southern Indian shield. Temperature measurements carried out in 10 boreholes at five sites in the craton, combined with systematic thermal conductivity measurements on major rock types, yield low heat flow in the range of 32–41 mW m−2, which is distinct from the generally high heat flow reported from other parts of the northern Indian shield. Radioelemental measurements on 243 samples of drill cores and outcrops reveal both large variability and high average heat production for the Neo‐Archaean to Palaeo‐Proterozoic granites (4.0 ± 2.1 (SD) μW m−3) relative to the Meso‐Archaean tonalite‐trondhjemite‐granodiorite (TTG) gneisses (2.0 ± 1.0 (SD) μW m−3). On the basis of new heat flow and heat production data sets combined with available geological and geophysical information, a set of steady state, heat flow‐crustal heat production models representative of varying crustal scenarios in the craton are envisaged. Mantle heat flow and Moho temperatures are found to be in the range of 12–22 mW m−2 and 290–420°C, respectively, not much different from those reported for the similar age Dharwar craton in southern India. This study reveals similar mantle thermal regimes across the northern and southern parts of the Indian shield, in spite of varying surface heat flow regimes, implying that much of the intraprovince and interprovince variations in the Indian shield are explained by variations in upper crustal heat production.
Real‐time prediction of the occurrence of GLE events
Authors: Núñez Marlon , Reyes‐Santiago Pedro J. , Malandraki Olga E. 
Published: June 2017

AbstractA tool for predicting the occurrence of Ground Level Enhancement (GLE) events using the UMASEP scheme is presented. This real‐time tool, called HESPERIA UMASEP‐500, is based on the detection of the magnetic connection, along which protons arrive in the near‐Earth environment, by estimating the lag correlation between the time derivatives of 1 min soft X‐ray flux (SXR) and 1 min near‐Earth proton fluxes observed by the GOES satellites. Unlike current GLE warning systems, this tool can predict GLE events before the detection by any neutron monitor (NM) station. The prediction performance measured for the period from 1986 to 2016 is presented for two consecutive periods, because of their notable difference in performance. For the 2000–2016 period, this prediction tool obtained a probability of detection (POD) of 53.8% (7 of 13 GLE events), a false alarm ratio (FAR) of 30.0%, and average warning times (AWT) of 8 min with respect to the first NM station's alert and 15 min to the GLE Alert Plus's warning. We have tested the model by replacing the GOES proton data with SOHO/EPHIN proton data, and the results are similar in terms of POD, FAR, and AWT for the same period. The paper also presents a comparison with a GLE warning system.
Chemo‐ and Enantioselective Intramolecular Silver‐Catalyzed Aziridinations
Authors: Ju Minsoo , Weatherly Cale D. , Guzei Ilia A. , Schomaker Jennifer M. 
Published: June 2017

AbstractAsymmetric nitrene‐transfer reactions are a powerful tool for the preparation of enantioenriched amine building blocks. Reported herein are chemo‐ and enantioselective silver‐catalyzed aminations which transform di‐ and trisubstituted homoallylic carbamates into [4.1.0]‐carbamate‐tethered aziridines in good yields and with ee values of up to 92 %. The effects of the substrate, silver counteranion, ligand, solvent, and temperature on both the chemoselectivity and ee value were explored. Stereochemical models were proposed to rationalize the observed absolute stereochemistry of the aziridines, which undergo nucleophilic ring opening to yield enantioenriched amines with no erosion in stereochemical integrity.
Unsupported Pt‐Ni Aerogels with Enhanced High Current Performance and Durability in Fuel Cell Cathodes
Authors: Henning Sebastian , Ishikawa Hiroshi , Kühn Laura , Herranz Juan , Müller Elisabeth , Eychmüller Alexander , Schmidt Thomas J. 
Published: June 2017

AbstractHighly active and durable oxygen reduction catalysts are needed to reduce the costs and enhance the service life of polymer electrolyte fuel cells (PEFCs). This can be accomplished by alloying Pt with a transition metal (for example Ni) and by eliminating the corrodible, carbon‐based catalyst support. However, materials combining both approaches have seldom been implemented in PEFC cathodes. In this work, an unsupported Pt‐Ni alloy nanochain ensemble (aerogel) demonstrates high current PEFC performance commensurate with that of a carbon‐supported benchmark (Pt/C) following optimization of the aerogel's catalyst layer (CL) structure. The latter is accomplished using a soluble filler to shift the CL's pore size distribution towards larger pores which improves reactant and product transport. Chiefly, the optimized PEFC aerogel cathodes display a circa 2.5‐fold larger surface‐specific ORR activity than Pt/C and maintain 90 % of the initial activity after an accelerated stress test (vs. 40 % for Pt/C).
Bismuth–Boron Multiple Bonding in BiB2O− and Bi2B−
Authors: Jian Tian , Cheung Ling Fung , Chen Teng‐Teng , Wang Lai‐Sheng 
Published: June 2017

AbstractDespite its electron deficiency, boron is versatile in forming multiple bonds. Transition‐metal–boron double bonding is known, but boron–metal triple bonds have been elusive. Two bismuth boron cluster anions, BiB2O− and Bi2B−, containing triple and double B−Bi bonds are presented. The BiB2O− and Bi2B− clusters are produced by laser vaporization of a mixed B/Bi target and characterized by photoelectron spectroscopy and ab initio calculations. Well‐resolved photoelectron spectra are obtained and interpreted with the help of ab initio calculations, which show that both species are linear. Chemical bonding analyses reveal that Bi forms triple and double bonds with boron in BiB2O− ([Bi≡B−B≡O]−) and Bi2B− ([Bi=B=Bi]−), respectively. The Bi−B double and triple bond strengths are calculated to be 3.21 and 4.70 eV, respectively. This is the first experimental observation of Bi−B double and triple bonds, opening the door to design main‐group metal–boron complexes with multiple bonding.
Top‐Down Fabrication of Stable Methylammonium Lead Halide Perovskite Nanocrystals by Employing a Mixture of Ligands as Coordinating Solvents
Authors: Huang He , Xue Qi , Chen Bingkun , Xiong Yuan , Schneider Julian , Zhi Chunyi , Zhong Haizheng , Rogach Andrey L. 
Published: June 2017

AbstractA top‐down method is demonstrated for the fabrication of CH3NH3PbBr3 and CH3NH3PbI3 perovskite nanocrystals, employing a mixture of ligands oleic acid and oleylamine as coordinating solvents. This approach avoids the use of any polar solvents, skips multiple reaction steps by employing a simple ultrasonic treatment of the perovskite precursors, and yields rather monodisperse blue‐, green‐, and red‐emitting methylammonium lead halide nanocrystals with a high photoluminescence quantum yield (up to 72 % for the green‐emitting nanocrystals) and remarkably improved stability. After discussing all relevant reaction parameters, the green‐emitting CH3NH3PbBr3 nanocrystals are employed as a component of down‐conversion white‐light‐emitting devices.
Integrated two‐stage adsorption for selective removal of CO2 and SO2 by amine‐functionalized SBA‐15
Authors: Wei L. , Gao Z. , Wang Y. 
Published: June 2017

AbstractA novel process for integrated two‐stage selective removal of CO2 and SO2 from a simulated flue gas by an adsorption method was developed. Triethylolamine (TEA)‐loaded SBA‐15 was selected as the SO2 adsorbent, and tetraethylenepentamine (TEPA)‐loaded SBA‐15 was the CO2 adsorbent. Scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, N2 adsorption/desorption, X‐ray photoelectron spectroscopy, and X‐ray diffraction techniques were used to characterize the properties of the adsorbents. The effects of the height–diameter ratio (H/D) of the adsorbent bed and operation temperature were tested for the removal of SO2. The results indicated that the pore volume and surface area of SBA‐15‐TEA‐50 and SBA‐15‐TEPA‐50 dropped with the increase of amine loading. SO2 breakthrough adsorption capacity of SBA‐15‐TEA‐50 was 146.3 mg of SO2/(g of adsorbent). The integrated two‐stage removal experiment of SO2 and CO2 over SBA‐15‐TEA and SBA‐15‐TEPA showed that CO2 and SO2 in gas mixture can be removed in two stages, respectively. Regeneration experiment showed that both the SO2 and CO2 breakthrough capacity almost kept a constant in the multiple cycles, and the regeneration of integrated two‐stage system was stable. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.
Spectral investigations on Eu3+,Sm3+‐doped and Sm3+/Eu3+ co‐doped potassium‐fluoro‐phosphate glass emitting intense orange‐red for lighting applications
Authors: Anil Kumar Kapuluri , Babu Singarapu , Reddy Prasad Vasanthapalli , Damodaraiah Samadam , Ratnakaram Yadala Chenchu 
Published: June 2017

AbstractPotassium fluoro‐phosphate (KFP) glass singly doped with different concentrations of europium (Eu3+) or samarium (Sm3+) or co‐doped (Sm3+/Eu3+) was prepared, and their luminescence spectra were investigated. The phase composition of the product was verified by X‐ray diffraction analysis. Optical transition properties of Eu3+ in the studied potassium phosphate glass were evaluated in the framework of the Judd–Ofelt theory. The radiative transition rates (AR), fluorescence branching ratios (β), stimulated emission cross‐sections (σe) and lifetimes (τexp) for certain transitions or levels were evaluated. Red emission of Eu3+ was exhibited mainly by the 5D0→7F2 transition located at 612 nm. Concentration quenching and energy transfer were observed from fluorescence spectra and decay curves, respectively. It was found that the lifetimes of the 5D0 level increased with increase in concentration and then decreased. By co‐doping with Sm3+, energy transfer from Sm3+ to Eu3+ occurred and contributed to the enhancement in emission intensity. Intense orange‐red light emission was obtained upon sensitizing with Sm3+ in KFP glass. This approach shows significant promise for use in reddish‐orange lighting applications. The optimized properties of the Sm3+/Eu3+ co‐doped potassium phosphate glass might be promising for optical materials.
Anticancer effects of oleuropein
Authors: Shamshoum Hesham , Vlavcheski Filip , Tsiani Evangelia 
Published: June 2017

AbstractCancer cells exhibit enhanced proliferation rate and a resistance to apoptosis. Epidemiological studies suggest that olive oil intake is associated with a reduced risk of cancer. Olive oil, olives, and olive leaves contain many polyphenols, including oleuropein. Recently, several studies have demonstrated that oleuropein inhibits proliferation and induces apoptosis in different cancer cell lines. In addition, anticancer effects of oleuropein have been seen in animal studies. These effects are associated with oleuropein's ability to modulate gene expression and activity of a variety of different signaling proteins that play a role in proliferation and apoptosis. This article summarizes the existing in vitro and in vivo studies focusing on the anticancer effects of oleuropein and its effects on key signaling molecules. © 2017 BioFactors, 43(4):517–528, 2017
Zeitmessung in biologischen Systemen
Authors: Prinzinger Roland 
Published: June 2017

ZusammenfassungLeben zeigt klare Abschnitte (zum Beispiel Embryo‐ und Ontogenese, Altern), deren Dauer man durch Allometrien beschreiben und zeitlich in chronologischen und/oder physiologischen Einheiten angeben kann. Erstere sind physikalisch auf der Basis der Abfolge von periodischen Ereignissen definiert. Sie können aber viele biologische Zeiten nicht befriedigend beschreiben. Biologische Uhren beruhen auf zahlreichen anderen Zeitmessern, die im Organismus selbst liegen und den gleichen Zeittakt zeigen und die nicht primär (nur) auf periodischen Abfolgen beruhen.
Ein Krebs für die Krebsforschung
Authors: Lyko Frank 
Published: June 2017

ZusammenfassungDer Marmorkrebs ist ein seit Mitte der 1990er Jahre bekannter triploider Flusskrebs, der sich parthenogenetisch fortpflanzt. Er stammt von der in Nord‐Amerika vorkommenden Decapoden‐Art Procambarus fallax ab und wurde als populäres Aquariumstier verbreitet. Aufgrund von Freisetzungen gibt es inzwischen eine Vielzahl von stabilen Freiland‐Populationen mit ernstzunehmendem invasiven Potenzial. Interessanterweise pflanzt sich der Marmorkrebs über einen parthenogenetischen Mechanismus fort, der zur Bildung einer klonalen Population mit minimaler genetischer Variabilität führt. Auch lassen sich die Tiere problemlos unter Laborbedingungen züchten und manipulieren. Diese Eigenschaften etablieren den Marmorkrebs als neuartigen und innovativen Modellorganismus für die Tumorbiologie, insbesondere für die Erforschung der klonalen Evolution und epigenetischen Anpassung von Tumorgenomen.
Vogelstimmen
Authors: Bergmann Hans‐Heiner 
Published: June 2017

ZusammenfassungVogelstimmen sind Teil der Biodiversität. Sie spielen eine Rolle bei der Artbildung. In vielen Fällen werden sie von Generation zu Generation tradiert und können Dialekte bilden. Man kann sie schwarz auf weiß aufzeichnen. Mit ihnen umzugehen, fällt vielen Menschen schwer. Für das Kennenlernen sind zahlreiche verschiedene Hilfsmittel verfügbar. Vogelstimmen zu erkunden kann zum Vergnügen werden und zugleich zu einem kognitiven Erlebnis, das von einer wachsenden Zahl von Menschen gesucht wird.
Wo lebten die ersten Zellen – und wovon?
Authors: Martin William F. , Zimorski Verena , Weiss Madeline C. 
Published: June 2017

ZusammenfassungDer letzte universelle gemeinsame Vorfahre allen Lebens (Luca) wurde lange als der gemeinsame Vorfahre von Bakterien, Archaeen und Eukaryoten betrachtet. Neue Stammbäume des Lebens zeigen jedoch den Ursprung der Eukaryoten innerhalb der Archaeen, somit wird Luca zum gemeinsamen Vorfahren der Bakterien und Archaeen. Informationen über Lucas Lebensraum und Lebensweise (Physiologie) gab es bisher nicht. Eine neue Arbeit konnte die mikrobielle Ökologie Lucas nun rekonstruieren. Nach phylogenetischen Kriterien gehen 355 Gene (Proteinfamilien) auf Luca zurück. Danach war Luca anaerob, CO2‐ und N2‐fixierend, H2‐abhängig und thermophil. Lucas Proteine waren reichlich mit FeS‐Zentren und radikalen Reaktionsmechanismen ausgestattet und erforderten Kofaktoren, bei denen Übergangsmetalle eine tragende Rolle spielen. Luca bewohnte eine geochemisch aktive Umgebung, die reich an H2, CO2 und Eisen war. Diese mikrobielle Ökologie ähnelt der heutiger acetogener Bakterien und methanogener Archaeen, den physiologisch ursprünglichsten Mikroben.
Bivalirudin or heparin for radial access?
Authors: Bittl John A. 
Published: June 2017

Key Points

Bivalirudin is a reasonable choice during transradial PCI for acute MI when bleeding risk is high and clopidogrel or cangrelor is used
Heparin is reasonable during transradial PCI when bleeding risk is low and high-intensity antiplatelet therapy is used
Future studies are required to define the utility of post-PCI bivalirudin infusions
Melody valve within a dysfunctional freestyle bioprosthesis: Yes, you can fit a round peg in a calcified hole
Authors: Parekh Dhaval R. , Krajcer Zvonimir 
Published: June 2017

Key Points

Transcatheter pulmonary valve implantation (TPVI) within a failed bioprosthetic valve is safe and effective
Coronary artery compression is a potential risk, requiring careful preimplantation balloon dilation testing
Prestenting is required for TPVI in stentless conduits
Improvements in right ventricular volume, pressure, pulmonary stenosis, and regurgitation can be maintained in the intermediate term
Long‐term risk for Melody valve endocarditis and valve dysfunction necessitates careful monitoring
Selective Levulinic Acid Hydrogenation in the Presence of Hybrid Dendrimer‐Based Catalysts. Part I: Monometallic
Authors: Maximov Anton L. , Zolotukhina Anna V. , Mamedli Adila A. , Kulikov Leonid A. , Karakhanov Edward A. 
Published: June 2017

AbstractHybrid Ru‐containing catalysts, based on poly(propylene imine) (PPI) dendrimers, immobilized in silica pores, were synthesized and characterized by transmission electron microscopy and X‐ray photoelectron spectroscopy. The synthesized Ru catalysts proved their efficiency in the selective hydrogenation of levulinic acid and its esters at 80 °C, 30 bar of H2, and 50 % volume substrate concentration in water. Quantitative yields of γ‐valerolactone were obtained for both micro‐ and mesoporous Ru catalysts within 2 h with catalytic activity as high as 1610 h−1. The reaction rate and selectivity on γ‐valerolactone were found to depend on several factors such as carrier structure, temperature, presence of water, and substrate/Ru ratio. The novelty of these hybrid materials is the presence of both weak acid (SiO2) and organic base centers (dendrimer amino groups), enhancing the dispersion of Ru nanoparticles. The presence of amino groups in the catalyst stabilizes the Ru nanoparticles during the synthesis and promotes the adsorption of levulinic acid on the surface of Ru nanoparticles during the reaction. Synthesized hybrid Ru catalysts can be reused several times without significant loss of activity.
Hierarchical Mn3O4 Microplates Composed of Stacking Porous Nanosheets for High‐Performance Lithium Storage
Authors: Ma Fei‐Xiang , Wu Hao Bin , Sun Xue‐Yin , Wang Pan‐Pan , Zhen Liang , Xu Cheng‐Yan 
Published: June 2017

AbstractTransition metal oxide based anodes with high capacities and long cycle lifetimes are considered promising candidates to substitute the conventional graphite electrodes with a relatively low capacity. In this work, hierarchical Mn3O4 microplates with a lateral size of approximately 4.9 μm, composed of stacking porous nanosheets with thicknesses as small as 10 nm, were synthesized by using a precursor conversion method. Such a nanosheet stacking arrangement possesses an unusual concave structure with a tight center and loose edge. Owing to the highly open hierarchical structure and good electronic conductivity from the in situ carbon, the as‐obtained hierarchical Mn3O4 microplate electrode exhibits remarkable cyclability up to 300 cycles at 500 mA g−1, accompanied with good rate capability (418 mA h g−1 at 2 A g−1).
Aggregation‐Induced Emission (AIE) Fluorophore Exhibits a Highly Ratiometric Fluorescent Response to Zn2+ in vitro and in Human Liver Cancer Cells
Authors: Mehdi Hassan , Gong Weitao , Guo Huimin , Watkinson Michael , Ma Hua , Wajahat Ali , Ning Guiling 
Published: June 2017

AbstractTwo novel organic fluorophores, containing bis‐naphthylamide and quinoline motifs, have been designed and synthesized. One of the fluorophores contains an isobutylene unit and exhibits a significant aggregation‐induced emission (AIE) and a remarkable highly selective ratiometric fluorescence response towards Zn2+ in solution as well as in human liver cancer cells. The AIE behavior of this fluorophore was fully verified by fluorescence and UV/Vis spectroscopy, quantum yield calculations, and single‐crystal X‐ray diffraction, which revealed an intricate crystal packing system. Conversely, a fluorophore that lacks the isobutylene moiety did not exhibit any significant fluorescent properties as a result of its more flexible molecular structure that presumably allows free intramolecular rotational processes to occur.