bluuebunny/crossref_metadata_2025_split huggingface dataset:
A revised global estimate of dissolved iron fluxes from marine sediments
Authors: Dale A. W. , Nickelsen L. , Scholz F. , Hensen C. , Oschlies A. , Wallmann K. 
Published: April 2015

AbstractLiterature data on benthic dissolved iron (DFe) fluxes (µmol m−2 d−1), bottom water oxygen concentrations (O2BW, μM), and sedimentary carbon oxidation rates (COX, mmol m−2 d−1) from water depths ranging from 80 to 3700 m were assembled. The data were analyzed with a diagenetic iron model to derive an empirical function for predicting benthic DFe fluxes: where γ (= 170 µmol m−2 d−1) is the maximum flux for sediments at steady state located away from river mouths. This simple function unifies previous observations that COX and O2BW are important controls on DFe fluxes. Upscaling predicts a global DFe flux from continental margin sediments of 109 ± 55 Gmol yr−1, of which 72 Gmol yr−1 is contributed by the shelf (<200 m) and 37 Gmol yr−1 by slope sediments (200–2000 m). The predicted deep‐sea flux (>2000 m) of 41 ± 21 Gmol yr−1 is unsupported by empirical data. Previous estimates of benthic DFe fluxes derived using global iron models are far lower (approximately 10–30 Gmol yr−1). This can be attributed to (i) inadequate treatment of the role of oxygen on benthic DFe fluxes and (ii) improper consideration of continental shelf processes due to coarse spatial resolution. Globally averaged DFe concentrations in surface waters simulated with the intermediate‐complexity University of Victoria Earth System Climate Model were a factor of 2 higher with the new function. We conclude that (i) the DFe flux from marginal sediments has been underestimated in the marine iron cycle and (ii) iron scavenging in the water column is more intense than currently presumed.
A protocol for variable‐resolution first‐order reversal curve measurements
Authors: Zhao Xiang , Heslop David , Roberts Andrew P. 
Published: April 2015

AbstractHigh‐resolution first‐order reversal curve (FORC) diagrams are being increasingly used in rock and environmental magnetism, including for detection of biomagnetic signals in sediments. Resolution can be a major barrier to obtaining high‐quality FORC diagrams, and time‐consuming measurements that employ small field steps are necessary to resolve the finest features of a FORC distribution. We present a new experimental protocol with irregularly spaced field steps that allow different parts of a FORC diagram to be measured at different resolutions. Larger numbers of measurements can, therefore, be made in key regions of a FORC distribution to resolve diagnostic features at higher resolution. Specification of the field steps in the irregular measurement grid is based on major hysteresis properties; no a priori knowledge concerning the underlying FORC distribution is required. FORC diagrams obtained with conventional measurements and with our new measurement protocol give consistent results. Because of its variable resolution, the irregular protocol provides a clear representation of fine‐scale features produced by quasireversible superparamagnetic and noninteracting single‐domain particles. Although the proposed irregular measurement protocol is not as efficient at suppressing noise as recently developed postprocessing techniques (e.g., VARIFORC), it enables efficient high‐resolution analysis for relatively strongly magnetized samples where measurement noise is not detrimental to FORC distribution estimation.
Evolution of precipitation and convective echo top heights observed by TRMM radar over the Indian Ocean during DYNAMO
Authors: Powell Scott W. , Houze Robert A. 
Published: April 2015

AbstractRadar data from the Tropical Rainfall Measuring Mission show the evolution of echo tops of convective elements over the Indian Ocean and Maritime Continent during the Dynamics of the Madden‐Julian Oscillation (DYNAMO) field campaign of 2011–2012. Echo top heights exhibited a bimodal distribution wherein cumulonimbi of moderate height constituted a “congestus mode” while vertically extensive cumulonimbus made up a “deep mode.” An intraseasonal time scale dominated variability in these modes from October to January over much of the Indian Ocean. Over the Maritime Continent, there was no clear intraseasonal signal in convective echo top heights. Where the intraseasonal oscillation was detected, radar echoes evolved from being dominated by the congestus mode to being characterized by more deep mode convection on time scales of less than 1 week. The areal coverage of congestus echoes began to increase 2–8 days prior to the rise in area of deep echoes. These satellite‐derived results confirm that the time scale for convective deepening seen at individual DYNAMO observational sites is consistent with that of convection on the large scale over the Indian Ocean. Intraseasonal variability of zonal wind, temperature, and humidity as depicted by reanalysis is also consistent with that derived from rawinsonde observations during DYNAMO. Thus, the gradual buildup of convection as depicted by recent versions of the “discharge‐recharge” hypothesis does not accurately describe evolutions of convection prior to MJO events observed during DYNAMO, although cloud moistening processes may still be relevant on time scales of 1 week or less.
Effects of earthquake ground motion on tracking characteristics of new Global Navigation Satellite System receivers
Authors: Berglund Henry T. , Blume Frederick , Prantner Andrea 
Published: April 2015

AbstractWe use a shake table capable of large (7 G) three‐dimensional accelerations with large payloads to simulate ground motion reconstructed from acceleration data collected during the February 2010 Mw = 8.8 Maule, Chile, earthquake. The tracking performance of five modern geodetic GNSS receiver and antenna combinations was investigated while undergoing simulated seismic shaking at three two levels of amplification. Individual system performance was characterized by the number of tracked GNSS observations. The L1 and L2 GPS signal tracking was significantly impacted for the majority of the receiver models during simulations with maximum accelerations of 4 G, and the tracking performance for all of the tested receiver types was significantly impaired during the 7 G simulations. Results show improved tracking when only the antenna was shaken suggesting that vibration‐induced oscillator phase noise may contribute significantly to tracking degradation during shaking.
Improved pattern scaling approaches for the use in climate impact studies
Authors: Herger Nadja , Sanderson Benjamin M. , Knutti Reto 
Published: April 2015

AbstractPattern scaling is a simple way to produce climate projections beyond the scenarios run with expensive global climate models (GCMs). The simplest technique has known limitations and assumes that a spatial climate anomaly pattern obtained from a GCM can be scaled by the global mean temperature (GMT) anomaly. We propose alternatives and assess their skills and limitations. One approach which avoids scaling is to consider a period in a different scenario with the same GMT change. It is attractive as it provides patterns of any temporal resolution that are consistent across variables, and it does not distort variability. Second, we extend the traditional approach with a land‐sea contrast term, which provides the largest improvements over the traditional technique. When interpolating between known bounding scenarios, the proposed methods significantly improve the accuracy of the pattern scaled scenario with little computational cost. The remaining errors are much smaller than the Coupled Model Intercomparison Project Phase 5 model spread.
Recent slowdown of tropical upper tropospheric warming associated with Pacific climate variability
Authors: Kamae Youichi , Shiogama Hideo , Watanabe Masahiro , Ishii Masayoshi , Ueda Hiroaki , Kimoto Masahide 
Published: April 2015

AbstractObserved upper tropospheric temperature over the tropics (TTUT) shows a slowdown in warming rate during 1997–2011 despite the continuous warming projected by coupled atmosphere‐ocean general circulation models (AOGCMs). This observation‐model discord is an underlying issue regarding the reliability of future climate projections based on AOGCMs. To investigate the slowdown, we conducted ensemble historical simulations using an atmospheric general circulation model (AGCM) forced by observed sea surface temperature both with and without anthropogenic influences. The historical AGCM run reproduced a muted TTUT change over the central Pacific (CP) found in multiple observations, while the multi‐AOGCM mean did not. Recent tropical Pacific cooling, which is considered natural variability, contributes to the muted trend over the CP and the resultant slowdown of TTUT increase. The results of this study suggest that difficulties in simulating the recent “upper tropospheric warming hiatus” do not indicate low reliability of AOGCM‐based future climate projections.
Particle distributions and dynamics in the euphotic zone of the North Pacific Subtropical Gyre
Authors: Barone Benedetto , Bidigare Robert R. , Church Matthew J. , Karl David M. , Letelier Ricardo M. , White Angelicque E. 
Published: April 2015

AbstractDuring the summer of 2012, we used laser diffractometry to investigate the temporal and vertical variability of the particle size spectrum (1.25–100 µm in equivalent diameter) in the euphotic zone of the North Pacific Subtropical Gyre. Particles measured with this optical method accounted for ∼40% of the particulate carbon stocks (<202 µm) in the upper euphotic zone (25–75 m), as estimated using an empirical formula to transform particle volume to carbon concentrations. Over the entire vertical layer considered (20–180 m), the largest contribution to particle volume corresponded to particles between 3 and 10 µm in diameter. Although the exponent of a power law parameterization suggested that larger particles had a lower relative abundance than in other regions of the global ocean, this parameter and hence conclusions about relative particle abundance are sensitive to the shape of the size distribution and to the curve fitting method. Results on the vertical distribution of particles indicate that different size fractions varied independently with depth. Particles between 1.25 and 2 µm reached maximal abundances coincident with the depth of the chlorophyll a maximum (averaging 121 ± 10 m), where eukaryotic phytoplankton abundances increased. In contrast, particles between 2 and 20 µm tended to accumulate just below the base of the mixed layer (41 ± 14 m). Variability in particle size tracked changes in the abundance of specific photoautotrophic organisms (measured with flow cytometry and pigment concentration), suggesting that phytoplankton population dynamics are an important control of the spatiotemporal variability in particle concentration in this ecosystem.
Metal‐Free Direct Aryltrifluoromethylation of Allylic Alcohols with Langlois’ Reagent through Concomitant 1,2‐Aryl Migration
Authors: Huang Hong‐Li , Yan Hang , Gao Guo‐Lin , Yang Chao , Xia Wujiong 
Published: April 2015

AbstractA metal‐free and cost‐effective synthetic protocol for selective aryltrifluoromethylation of allylic alcohols with Langlois’ reagent (CF3SO2Na) through cascade trifluoromethyl radical addition/1,2‐aryl migration has been developed. The highlights of this procedure are operational simplicity, excellent functional group tolerance, and mild reaction conditions.
Facile Self‐Assembly of Metallo‐Supramolecular Ring‐in‐Ring and Spiderweb Structures Using Multivalent Terpyridine Ligands
Authors: Fu Jun‐Hao , Lee Yin‐Hsuan , He Yun‐Jui , Chan Yi‐Tsu 
Published: April 2015

AbstractA series of metallo‐supramolecular ring‐in‐ring structures was generated by assembling CdII ions and the multivalent terpyridine ligands (L1‐3) composed of one 60°‐bent and two 120°‐bent bis(terpyridine)s with varying alkyl linker lengths. The mechanistic study for the self‐assembly process excluded an entropically templated pathway and showed that the intramolecularly complexed species is the key intermediate leading to ring‐in‐ring formation. The next‐generation superstructure, a spiderweb, was produced in quantitative yield using the elongated decakis(terpyridine) ligand (L5).
Thermal degradation kinetics of a commercial epoxy resin—Comparative analysis of parameter estimation methods
Authors: Chairat Aziza , Joulia Xavier , Floquet Pascal , Vergnes Hugues , Ablitzer Carine , Fiquet Olivier , Brothier Meryl 
Published: April 2015

ABSTRACTThe thermal degradation behavior of a commercial epoxy resin, EpoFix® (Struers), has been investigated by thermogravimetry (TG), differential thermal gravimetry (DTG), and differential thermal analysis (DTA) under nonisothermal conditions in an argon atmosphere. Different methods (Kissinger, Flynn–Wall–Ozawa (FWO), Friedman isoconversion methods, and nonlinear least‐squares (NLSQ) estimation method) have been used to analyze the thermal degradation process and determine the apparent kinetic parameters. The methods produce similar results in terms of activation energy estimations. Nevertheless, the NLSQ method has several advantages over the other methods in terms of both characterizing the activation energy and modeling the thermal degradation—i.e., including this model in a resin degradation process simulation. However, it is interesting to combine the NLSQ method with other isoconversion methods: they can reflect the dependence and variability of the activation energies during pyrolysis processes, while providing a good starting point for a nonlinear procedure, especially with respect to the activation energy E. This work is the first step (apparent kinetic reaction) of complete simulation of experimental oven of degradation of epoxy resin coating of impregnate nuclear fuel sample. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42201.
Identification of NF‐κB inhibitors in Qishenyiqi dropping pills for myocardial infarction treatment based on bioactivity‐integrated UPLC‐Q/TOF MS
Authors: Han Yanqi , Zhou Mengge , Xing Lu , Jiang Min , Bai Gang , Luo Guoan 
Published: April 2015

AbstractQishenyiqi dropping pills (QSYQ) are a type of standardized cardiovascular multiherb medicine for the treatment of myocardial infarction (MI). Knowledge concerning the systemic identification of nuclear factor‐kappa B (NF‐κB) inhibitors of QSYQ is generally lacking. Therefore, it is necessary to establish an effective method to screen the bioactive components of NF‐κB inhibition. In the present study, a rat model of coronary artery ligation was used to assess the cardioprotective effects of QSYQ. The electrocardiograms, histopathology of heart tissues and serum biochemical indicators, such as brain natriuretic peptide, cardiac troponin I and inflammatory cytokines, were measured. Subsequently, ultra‐performance liquid chromatography quadrupole/time‐of‐flight mass spectrometry (UPLC‐Q/TOF MS) combined with the NF‐κB luciferase reporter assay system was applied to screen the potential anti‐inflammatory compounds in QSYQ. The results revealed that the administration of QSYQ could improve heart function, ameliorate neutrophil infiltration and diminish the levels of inflammatory cytokines in MI rats. Furthermore, 22 compounds were determined to be potential NF‐κB inhibitors. In conclusion, NF‐κB inactivation and cytokine suppression might be the main mechanisms of QSYQ for MI treatment. The method of UPLC‐Q/TOF MS combined with a bioactive human cell functional evaluation system was proved to be a simple and effective strategy for screening bioactive compounds in traditional Chinese medicine prescriptions. Copyright © 2015 John Wiley & Sons, Ltd.
Aortic and coronary aneurysms: Are they really distinct entities?
Authors: Mastoris Ioannis , Mehran Roxana 
Published: April 2015

Key Points
Connective tissue/inflammatory diseases affecting the aorta and coronaries should be considered as continuum
Patients with both atherosclerotic and non‐atherosclerotic aneurysms should be properly treated for hypertension
Physicians should stay alert of the potential coexistence of the two entities.
Combination of Reaction and Separation in Heterogeneous Catalytic Hydrogenation of Ethylformate
Authors: Martin Gerson , Pereira Carla , Pettersson Frank , Saxén Henrik , Murzin Dmitry Y. , Rodrigues Alírio , Salmi Tapio 
Published: April 2015

AbstractContinuous hydrogenation reaction of ethyl benzoylformate was studied over a (–)‐cinchonidine (CD)‐modified Pt/Al2O3 catalyst. The catalyst showed a good stability, and high enantioselectivity was achieved in the fixed‐bed reactor. Chromatographic separation of (R)‐ and (S)‐ethyl mandelate originating from a post‐continuous hydrogenation reaction of ethyl benzoylformate over the (–)‐CD‐modified Pt/Al2O3 catalyst was investigated in the same reaction mixture. A commercial column filled with a chiral selector resin was chosen as a perspective preparative‐scale adsorbent. Since adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post‐reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug‐flow model with linear driving force approximation.
Asymmetric Copper‐Catalyzed Vinylogous Mukaiyama Michael Addition of Cyclic Dienol Silanes to Unsaturated α‐Keto Phosphonates
Authors: Steinkamp Anne‐Dorothee , Frings Marcus , Thomé Isabelle , Schiffers Ingo , Bolm Carsten 
Published: April 2015

AbstractA highly stereoselective vinylogous Mukaiyama Michael reaction (VMMR) leading to α‐keto phosphonate‐containing γ‐butenolides with two stereogenic centers is described. The presented transformation is catalyzed by a combination of a commercially available C2‐symmetric bisoxazoline (BOX) ligand and a copper salt and tolerates a variety of nucleophiles and electrophiles. The stereoselectivities of the reactions are good to excellent and the products are obtained in moderate to high yields.
Produktschonende Betriebs‐ und Designparameter von Wärmeübertragern für temperaturempfindliche Prozessströme
Authors: Dippel Moritz , Grünewald Marcus 
Published: April 2015

AbstractUm die Berechnung von Produktschädigungsraten als Erweiterung der üblichen wärmetechnischen Auslegungsrechnungen von Wärmeübertragern zu ermöglichen, wird ein volumenbezogener, reaktionskinetischer Ansatz entwickelt. Dazu wird ein Modellstoffsystem ausgewählt und simulationsgestützt möglichst produktschonende Betriebsparameter für einen Laborwärmeübertrager ermittelt. Die Validierung kann im Experiment demonstriert werden. Weiterhin werden produktschonende Betriebsparameter im Laborwärmeübertrager mit einem technisch relevanten Stoffsystem berechnet.
Multifunctional MgO Layer in Perovskite Solar Cells
Authors: Guo Xudong , Dong Haopeng , Li Wenzhe , Li Nan , Wang Liduo 
Published: April 2015

AbstractA multifunctional magnesium oxide (MgO) layer was successfully introduced into perovskite solar cells (PSCs) to enhance their performance. MgO was coated onto the surface of mesoporous TiO2 by the decomposition of magnesium acetate and, therefore, could block contact between the perovskite and TiO2. X‐ray photoelectron spectroscopy and infrared spectroscopy showed that the amount of H2O/hydroxyl absorbed on the TiO2 decreased after MgO modification. The UV/Vis absorption spectra of the perovskite with MgO modification revealed an enhanced photoelectric performance compared with that of unmodified perovskite after UV illumination. In addition to the photocurrent, the photovoltage and fill factor also showed an enhancement after modification, which resulted in an increase in the overall efficiency of the cell from 9.6 to 13.9 %. Electrochemical impedance spectroscopy (EIS) confirmed that MgO acts as an insulating layer to reduce charge recombination.
Evapotranspiration over artificially planted shrub communities in the shifting sand dune area of the Tengger Desert, north central China
Authors: Gao Yanhong , Liu Lichao , Jia Rongliang , Yang Haotian , Li Gang 
Published: April 2015

AbstractRevegetation is a common method to combat desertification in arid and semi‐arid areas worldwide. The objective of this study was to characterize the evapotranspiration (ET) of a 20‐year‐old revegetated area of the Tengger Desert. During the measurement period from 2009 to 2012, ET was measured by the eddy covariance technique. The result showed that the values for mean daily ET were 0.43, 0.39, 0.43 and 0.59 mm d−1 in 2009–2012, respectively. In the non‐growing season, the diurnal ET variation showed a normal distribution with a maximum value occurring at noon, while it showed multimodal distribution trend occurred in a dry day and a unimodal trend in a wet day with a maximum value occurring at noon in the growing season. During the 4‐year measurements, despite the large inter‐annual variation of precipitation (annual mean precipitation of 164.4 ± 33.5 mm), the water loss through ET (667.5 mm) was almost equal to rainfall (657.8 mm), and the mean of ET/P was 1.01.The annual ET amounts were 153.6, 143.3, 156.2 and 214.4 mm y−1 in 2009–2012, respectively, with corresponding ratio between accumulated ET and precipitation (ET/P) of 1.03, 1.14, 0.82 and 1.12. This indicated that the annual ET amounts can be modified by the soil water storage, which led to water loss through ET exceeding the water input by precipitation in a drier year, and soil water can be replenished in a wetter year. Thus, the vegetation protection system using plantations of xerophyte shrubs in the present study area is a success with a trade‐off of acceptable hydrological consequences that deserve to be popularized. Copyright © 2015 John Wiley & Sons, Ltd.
Rhodium(III)‐Catalyzed [2+2+2] Cyclotrimerization of Diynes with Maleic Anhydrides as Alkyne Equivalents
Authors: Matsuda Takanori , Suzuki Kentaro 
Published: April 2015

AbstractSubstituted maleic anhydrides function as synthetic equivalents of alkynes in a rhodium(III)‐catalyzed reaction with 1,6‐diynes to achieve a formal [2+2+2] cyclotrimerization. This approach is useful for reactions involving alkynes with low boiling points or severe ring strain. Hard‐to‐access [2+2+2] cycloadducts are available through this new cycloaddition strategy by employing easy‐to‐handle alkyne equivalents.
Copper(I)‐Catalysed Domino Coupling and Cyclisation Reaction: A Mild, Expedient Route for the Synthesis of Indene and Dihydronaphthalene Derivatives
Authors: Kumaraswamy Gullapalli , Balakishan Guniganti 
Published: April 2015

AbstractA substoichiometric copper iodide catalysed synthesis of indene and dihydronaphthalene derivatives has been accomplished. This protocol is compatible with functional groups, and results in various scaffolds of indene and dihydronaphthalene derivatives in good to high yields. By employing this protocol, a functionalised cyclohexenone derivative is also achieved.