bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crustal thinning in the northern Tyrrhenian Rift: Insights from multichannel and wide‐angle seismic data across the basin
Authors: Moeller S. , Grevemeyer I. , Ranero C. R. , Berndt C. , Klaeschen D. , Sallares V. , Zitellini N. , de Franco R. 
Published: February 2014

AbstractExtension of the continental lithosphere leads to the formation of rift basins or rifted continental margins if breakup occurs. Seismic investigations have repeatedly shown that conjugate margins have asymmetric tectonic structures and different amount of extension and crustal thinning. Here we compare two coincident wide‐angle and multichannel seismic profiles across the northern Tyrrhenian rift system sampling crust that underwent different stages of extension from north to south and from the flanks to the basin center. Tomographic inversion reveals that the crust has thinned homogeneously from ~24 km to ~17 km between the Corsica Margin and the Latium Margin implying a β factor of ~1.3–1.5. On the transect 80 km to the south, the crust thinned from ~24 km beneath Sardinia to a maximum of ~11 km in the eastern region near the Campania Margin (β factor of ~2.2). The increased crustal thinning is accompanied by a zone of reduced velocities in the upper crust that expands progressively toward the southeast. We interpret that the velocity reduction is related to rock fracturing caused by a higher degree of brittle faulting, as observed on multichannel seismic images. Locally, basalt flows are imaged intruding sediment in this zone, and heat flow values locally exceed 100 mW/m2. Velocities within the entire crust range 4.0–6.7 km/s, which are typical for continental rocks and indicate that significant rift‐related magmatic underplating may not be present. The characteristics of the pre‐tectonic, syn‐tectonic and post‐tectonic sedimentary units allow us to infer the spatial and temporal evolution of active rifting. In the western part of the southern transect, thick postrift sediments were deposited in half grabens that are bounded by large fault blocks. Fault spacing and block size diminish to the east as crustal thinning increases. Recent tectonic activity is expressed by faults cutting the seafloor in the east, near the mainland of Italy. The two transects show the evolution from the less extended rift in the north with a fairly symmetric conjugate structure to the asymmetric margins farther south. This structural evolution is consistent with W‐E rift propagation and southward increasing extension rates.
Impact of satellite rainfall assimilation on Weather Research and Forecasting model predictions over the Indian region
Authors: Kumar Prashant , Kishtawal C. M. , Pal P. K. 
Published: February 2014

AbstractRainfall is probably the most important parameter that is predicted by numerical weather prediction models, though the skill of rainfall prediction is the poorest compared to other parameters, e.g., temperature and humidity. In this study, the impact of rainfall assimilation on mesoscale model forecasts is evaluated during Indian summer monsoon 2011. The Weather Research and Forecasting (WRF) model and its four‐dimensional variational data assimilation system are used to assimilate the Tropical Rainfall Measuring Mission 3B42 and Japan Aerospace Exploration Agency Global Satellite Mapping of Precipitation retrieved rainfall. A total of five experiments are performed daily with and without assimilation of rainfall data during the entire month of July 2011. Separate assimilation experiments are performed to assess the sensitivity of WRF model forecast with strict and less strict quality control. Assimilation of rainfall improves the forecast of temperature, specific humidity, and wind speed. Domain average improvement parameter of rainfall forecast is also improved over the Indian landmass when compared with NOAA Climate Prediction Center Morphing technique and Indian Meteorological Department gridded rainfall.
Stratospheric ozone response to sulfate geoengineering: Results from the Geoengineering Model Intercomparison Project (GeoMIP)
Authors: Pitari Giovanni , Aquila Valentina , Kravitz Ben , Robock Alan , Watanabe Shingo , Cionni Irene , Luca Natalia De , Genova Glauco Di , Mancini Eva , Tilmes Simone 
Published: February 2014

AbstractGeoengineering with stratospheric sulfate aerosols has been proposed as a means of temporarily cooling the planet, alleviating some of the side effects of anthropogenic CO2 emissions. However, one of the known side effects of stratospheric injections of sulfate aerosols under present‐day conditions is a general decrease in ozone concentrations. Here we present the results from two general circulation models and two coupled chemistry‐climate models within the experiments G3 and G4 of the Geoengineering Model Intercomparison Project. On average, the models simulate in G4 an increase in sulfate aerosol surface area density similar to conditions a year after the Mount Pinatubo eruption and a decrease in globally averaged ozone by 1.1−2.1 DU (Dobson unit, 1 DU = 0.001 atm cm) during the central decade of the experiment (2040–2049). Enhanced heterogeneous chemistry on sulfate aerosols leads to an ozone increase in low and middle latitudes, whereas enhanced heterogeneous reactions in polar regions and increased tropical upwelling lead to a reduction of stratospheric ozone. The increase in UV‐B radiation at the surface due to ozone depletion is offset by the screening due to the aerosols in the tropics and midlatitudes, while in polar regions the UV‐B radiation is increased by 5% on average, with 12% peak increases during springtime. The contribution of ozone changes to the tropopause radiative forcing during 2040–2049 is found to be less than −0.1 W m−2. After 2050, because of decreasing ClOx concentrations, the suppression of the NOx cycle becomes more important than destruction of ozone by ClOx, causing an increase in total stratospheric ozone.
Least‐squares‐based adaptive target localization by mobile distance measurement sensors
Authors: Fidan Barış , Çamlıca Ahmet , Güler Samet 
Published: February 2014

SummaryA least‐squares‐based adaptive algorithm with forgetting factor is proposed for localization of a target by a mobile distance measurement sensor. This problem, in its most general form, was tackled in a recent paper using a gradient adaptive algorithm, assuming distance measurements are directly available. We establish that the proposed algorithm bears the same stability and convergence properties as the gradient algorithm previously studied. It is demonstrated via simulations that the proposed algorithm converges significantly faster to the location estimates than the gradient algorithm for high forgetting factor values and significantly reduces the noise effects for small values of the forgetting factor. Furthermore, a more challenging form of the original problem is considered, where distance information is required to be deduced from time of flight measurements, considering a time of flight‐based active distance measurement sensor and an environment with unknown signal permittivity/speed; the proposed algorithm is redesigned to solve this problem. Copyright © 2014 John Wiley & Sons, Ltd.
Practical Iron‐Catalyzed Hydrogen Peroxide Epoxidation of Aromatic Olefins using a Combination of Two Kinds of Simple Picolinate Ligands under Halide‐Free Reaction Conditions
Authors: Chishiro Takefumi , Kon Yoshihiro , Nakashima Takuya , Goto Midori , Sato Kazuhiko 
Published: February 2014

AbstractHigh‐yield syntheses of epoxides using an iron complex having two types of picolinates in the presence of hydrogen peroxide under halide‐free reaction conditions were achieved. The reaction is very simple. The complex, prepared with iron(II) acetate, 2‐picolinic acid (picH) and 6‐methyl‐2‐picolinic acid (Me‐picH) in acetonitrile, quickly catalyzed an epoxidation of styrene (15 min.) at 25 °C with 1.40 equivalents of 35% aqueous hydrogen peroxide solution to afford styrene oxide in 95% yield with 96% selectivity. We also carried out a 100‐g scale epoxidation of styrene using 1.25 equivalents of 35% aqueous hydrogen peroxide solution with the iron catalyst to give styrene oxide in 80% isolated yield. The developed iron catalyst was efficiently applicable to the epoxidation of various aromatic olefins to give the corresponding epoxides in high yields. To obtain more information about this catalytic system, the pre‐catalyst of this reaction was isolated and the structure was determined to be [Fe(pic)(Me‐pic)2] by single‐crystal X‐ray analysis. The [Fe(pic)(Me‐pic)2] catalyst effectively epoxidized styrene to styrene oxide in 93% yields. The system should be suitable for large‐scale preparations of aromatic olefins due to the employment of simple ligands with halide‐ and amine‐free reaction conditions.magnified image
Hosts for High‐Performance Phosphorescent Organic Light‐Emitting Diodes Based on Carbazole Derivatives
Authors: Jiang Hongji 
Published: February 2014

AbstractOrganic electroluminescent (EL) materials have many advantages when compared with their inorganic counterparts and, therefore, they have a wide range of potential applications in communication, information display, illumination, and so on. Phosphorescent organic light‐emitting diodes (PHOLEDs) that contain late transition‐metal complexes as emitters are particularly attractive due to their ability to harvest singlet and triplet excitons, which makes it possible to achieve an internal quantum efficiency of 100 %. To suppress concentration quenching, a phosphorescent emitter is usually dispersed in a suitable host to obtain a high photoluminescent quantum yield. Developing a host with a suitable triplet energy level, charge‐transporting ability, and thermal and film stability is thus the key to improving the performance of PHOLEDs. Carbazole‐based chromophores are widely used in the synthesis of highly efficient hosts for PHOLEDs. However, these compounds are not universal or unique segments for constructing high performance hosts. Herein, up‐to‐date methods for chemical modifications to obtain hosts for high‐performance PHOLEDs based on carbazole derivatives are presented in detail. These methods include heterocycle replacement and extension of the conjugated structure of the carbazole skeleton. Finally, some issues to be addressed and hotspots to be further investigated are also discussed.
Potential‐Driven Chirality Manifestations and Impressive Enantioselectivity by Inherently Chiral Electroactive Organic Films
Authors: Sannicolò Francesco , Arnaboldi Serena , Benincori Tiziana , Bonometti Valentina , Cirilli Roberto , Dunsch Lothar , Kutner Włodzimierz , Longhi Giovanna , Mussini Patrizia R. , Panigati Monica , Pierini Marco , Rizzo Simona 
Published: February 2014

AbstractThe typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly‐heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3′‐bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co‐planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system.
Synthesis and solar cells applications of EO‐PF‐DTBT polymer
Authors: Zhou Lina , Bao Xichang , Liu Qian , Yu Jieliang , Chen Yanhua , Yang Renqiang , Sun Mingliang 
Published: February 2014

ABSTRACTPoly{[2,7‐(9,9‐bis‐(1‐(2‐(2‐methoxyethoxy)ethoxy)ethyl)‐fluorene)]‐alt‐[5,5‐(4,7‐di‐2′‐thienyl‐2,1,3‐benzothiadiazole)]} (EO‐PF‐DTBT) was synthesized by Suzuki coupling reaction. The polymer is soluble in common organic solvent, such as toluene, THF, and chloroform, and it also shows solubility in polar solvent, such as cyclopentanone. Solar cells based on EO‐PF‐DTBT and PC61BM show maximum power conversion efficiency of 2.65% with an open circuit voltage (VOC) of 0.86 V, a short circuit current density (JSC) of 6.10 mA/cm2, and a fill factor of 51% under AM 1.5G illumination at 100 mW/cm2, which is the best results for fluorene and 4,7‐di‐2‐thienyl‐2,1,3‐benzothiadiazole copolymers and PC61BM blend. The 1,8‐diiodooctane can work well to reduce the over‐aggregated phase structure in polymer solar cells. Our results suggest that the introducing high hydrophilic side chain into conjugated polymer donor materials can tune the aggregation structure and improve the solar cells performances. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40478.
Morphological analysis of crease patterns formed on surface‐attached hydrogel with a gradient in thickness
Authors: Kim Jungwook 
Published: February 2014

ABSTRACTThe morphology of crease pattern formed on the surface‐attached hydrogel with a gradient in thickness is analyzed. We label the hydrogel surface at the creased state with fluorescent polyelectrolyte, which enables us to visualize surface morphology of creases using the fluorescent microscopy. Various morphological features of crease patterns are analyzed at different thickness of hydrogel, or characteristic spacing of creases λc,max, to examine the self‐similarity of crease morphology at different length scales. Some morphological features show no λc,max dependence, implying the self‐similarity, while others show weak λc,max dependence with positive values of the exponent of power law fit for the plots. We infer that such nonself‐similarity is originated from the variations in the kinetics of swelling and creasing of hydrogel, the effect of surface tension, or the reduction in the osmotic pressure occurred during the polyelectrolyte labeling step at different λc,max. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40482.
Recovery potential of smalltooth sawfish, Pristis pectinata, in the United States determined using population viability models
Authors: Carlson John K. , Simpfendorfer Colin A. 
Published: February 2014

Abstract

Determining the recovery potential of endangered species is an important component for developing strategies necessary to return populations to healthy levels. Many species of endangered marine animals have been regarded as having low productivity and therefore, an inherent inability to rapidly recover from severe depletion.
An age‐structured Leslie matrix model was constructed for the US population of smalltooth sawfish, Pristis pectinata, to determine their ability to recover under scenarios using different life history inputs and the effects of bycatch mortality and catastrophes.
Population growth was highest (λ=1.237 yr‐1) when age‐at‐maturity was 7 yr and decreased to 1.150 yr‐1 when age‐at‐maturity was 11 yr.
Despite a high level of variability throughout the model runs, in the absence of fishing mortality or climate catastrophic effects the population grew at a relatively rapid rate approaching carrying capacity in 40 or 50 yr when the initial population was 600 or 2250 females, respectively. Population projections under various levels of fishing mortality resulted in extinction when mortality was highest, initial population size was small, and age‐at‐maturity was 11 yr. Scenarios testing the potential effects of extreme cold exposure showed little difference to those scenarios testing the effects of fishing mortality.
Using the optimistic estimates of population size, lower age‐at‐maturity and the lower level of fisheries‐related mortality, smalltooth sawfish in US waters appear to have the ability to recover within the foreseeable future. Effective management and recovery of this species can only be achieved by keeping fishing‐related mortality low. Copyright © 2014 John Wiley & Sons, Ltd.
Hydrogen‐Bond and Metal–Ligand Coordination Bond Hybrid Supramolecular Capsules: Identification of Hemicapsular Intermediate and Dual Control of Guest Exchange Dynamics
Authors: Nito Yuki , Adachi Hirofumi , Toyoda Naoaki , Takaya Hikaru , Kobayashi Kenji , Yamanaka Masamichi 
Published: February 2014

AbstractHybrid supramolecular capsules self‐assemble by simultaneously forming hydrogen and metal–ligand coordination bonds on mixing a C2‐symmetrical cavitand (calix[4]resorcinarene‐based cavitands with ureide and terminal 4‐pyridyl units) with platinum or palladium complexes ([Pt(OTf)2] or [Pd(OTf)2] with chelating bisphosphines) in 1:1 ratio. Hemicapsular assemblies formed in the presence of excess amounts of cavitand relative to the platinum or palladium complexes are identified as intermediates in the above self‐assembly process by 2D‐NOESY spectroscopy. External‐anion‐assisted encapsulation of a neutral guest, 4,4′‐diiodobiphenyl, inside the hybrid supramolecular capsules accompanied conformational changes in the hydrogen‐bonding moieties. The in/out exchange ratio of the encapsulated guest depends on the bite angle of the bisphosphine ligand. Addition of DMSO accelerates guest exchange by weakening the hydrogen bonds in the encapsulation complex. Therefore, variations in the structure of the metal complex and amount of polar solvent exert dual control on the dynamics of the guest exchange.
Metabolism of methylstenbolone studied with human liver microsomes and the uPA+/+‐SCID chimeric mouse model
Authors: Geldof Lore , Lootens Leen , Polet Michael , Eichner Daniel , Campbell Thane , Nair Vinod , Botrè Francesco , Meuleman Philip , Leroux‐Roels Geert , Deventer Koen , Eenoo Peter Van 
Published: February 2014

ABSTRACTAnti‐doping laboratories need to be aware of evolutions on the steroid market and elucidate steroid metabolism to identify markers of misuse. Owing to ethical considerations, in vivo and in vitro models are preferred to human excretion for nonpharmaceutical grade substances. In this study the chimeric mouse model and human liver microsomes (HLM) were used to elucidate the phase I metabolism of a new steroid product containing, according to the label, methylstenbolone. Analysis revealed the presence of both methylstenbolone and methasterone, a structurally closely related steroid. Via HPLC fraction collection, methylstenbolone was isolated and studied with both models. Using HLM, 10 mono‐hydroxylated derivatives (U1–U10) and a still unidentified derivative of methylstenbolone (U13) were detected. In chimeric mouse urine only di‐hydroxylated metabolites (U11–U12) were identified. Although closely related, neither methasterone nor its metabolites were detected after administration of isolated methylstenbolone. Administration of the steroid product resulted mainly in the detection of methasterone metabolites, which were similar to those already described in the literature. Methylstenbolone metabolites previously described were not detected. A GC‐MS/MS multiple reaction monitoring method was developed to detect methylstenbolone misuse. In one out of three samples, previously tested positive for methasterone, methylstenbolone and U13 were additionally detected, indicating the applicability of the method. Copyright © 2014 John Wiley & Sons, Ltd.
More than just a Halogenase: Modification of Fatty Acyl Moieties by a Trifunctional Metal Enzyme
Authors: Pratter Sarah M. , Ivkovic Jakov , Birner‐Gruenberger Ruth , Breinbauer Rolf , Zangger Klaus , Straganz Grit D. 
Published: February 2014

AbstractThe highly selective oxidative halogenations by non‐heme iron and α‐ketoglutarate‐dependent enzymes are key reactions in the biosynthesis of lipopeptides, and often bestow valuable bioactivity to the metabolites. Here we present the first biochemical characterization of a putative fatty acyl halogenase, HctB, which is found in the hectochlorin biosynthetic pathway of Lyngbya majuscula. Its unprecedented three‐domain structure, which includes an acyl carrier protein domain, allows self‐contained conversion of the covalently tethered hexanoyl substrate. Structural analysis of the native product by 13C NMR reveals high regioselectivity but considerable catalytic promiscuity. This challenges the classification of HctB as a primary halogenase: along with the proposed dichlorination, HctB performs oxygenation and an unprecedented introduction of a vinyl‐chloride moiety into the nonactivated carbon chain. The relaxed substrate specificity is discussed with reference to a molecular model of the enzyme–substrate complex. The results suggest that fatty acyl transformation at the metal center of HctB can bring about considerable structural diversity in the biosynthesis of lipopeptides.
Arrays of Screen‐Printed Graphite Microband Electrodes as a Versatile Electroanalysis Platform
Authors: Vagin Mikhail Yu. , Sekretaryova Alina N. , Reategui Rafael Sanchez , Lundstrom Ingemar , Winquist Fredrik , Eriksson Mats 
Published: February 2014

AbstractArrays of microband electrodes were developed by screen printing followed by cutting, which enabled the realization of microband arrays at the cut edge. The microband arrays of different designs were characterized by physical and electrochemical methods. In both cases, the methods showed that the microband width was around 5 μm. Semi‐steady‐state cyclic voltammetry responses were observed for redox probes, and chronocoulometric measurements showed the establishment of convergent diffusion regimes characterized by current densities similar to those of a single microelectrode. The analytical performance of the electrode system and its versatility were illustrated with two electrochemical assays: detection of ascorbic acid through direct oxidation and a mediated glucose biosensor fabricated by dip coating. Due to convergent mass transport, both systems showed an enhancement in their analytical characteristics. The developed approach can be adapted to automated electrode recovery.
Polymeric Carbon Nitride/Mesoporous Silica Composites as Catalyst Support for Au and Pt Nanoparticles
Authors: Xiao Ping , Zhao Yanxi , Wang Tao , Zhan Yingying , Wang Huihu , Li Jinlin , Thomas Arne , Zhu Junjiang 
Published: February 2014

AbstractSmall and homogeneously dispersed Au and Pt nanoparticles (NPs) were prepared on polymeric carbon nitride (CNx)/mesoporous silica (SBA‐15) composites, which were synthesized by thermal polycondensation of dicyandiamide‐impregnated preformed SBA‐15. By changing the condensation temperature, the degree of condensation and the loading of CNx can be controlled to give adjustable particle sizes of the Pt and Au NPs subsequently formed on the composites. In contrast to the pure SBA‐15 support, coating of SBA‐15 with polymeric CNx resulted in much smaller and better‐dispersed metal NPs. Furthermore, under catalytic conditions the CNx coating helps to stabilize the metal NPs. However, metal NPs on CNx/SBA‐15 can show very different catalytic behaviors in, for example, the CO oxidation reaction. Whereas the Pt NPs already show full CO conversion at 160 °C, the catalytic activity of Au NPs seems to be inhibited by the CNx support.
Bioinspired Intramolecular Diels–Alder Reaction: A Rapid Access to the Highly‐Strained Cyclopropane‐Fused Polycyclic Skeleton
Authors: Zhu Shifa , Guo Zhengjiang , Huang Zhipeng , Jiang Huanfeng 
Published: February 2014

AbstractA bioinsipred gold‐catalyzed tandem Diels–Alder/Diels–Alder reaction of an enynal and a 1,3‐diene, forming the highly‐strained benzotricyclo[3.2.1.02,7]octane skeleton, was reported. In contrast, a Diels–Alder/Friedel–Crafts tandem reaction occurred instead when silver salts were used as the catalyst. Although both reactions experienced the similar Diels–Alder reaction of a pyrylium intermediate with a 1,3‐diene, they have different reaction mechanisms. The former proceeded with a stepwise Diels–Alder reaction, while the latter one with a concerted one.