bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mid‐ocean ridge eruptions as a climate valve
Authors: Tolstoy Maya 
Published: February 2015

AbstractSeafloor eruption rates and mantle melting fueling eruptions may be influenced by sea level and crustal loading cycles at scales from fortnightly to 100 kyr. Recent mid‐ocean ridge eruptions occur primarily during neap tides and the first 6 months of the year, suggesting sensitivity to minor changes in tidal forcing and orbital eccentricity. An ~100 kyr periodicity in fast‐spreading seafloor bathymetry and relatively low present‐day eruption rates at a time of high sea level and decreasing orbital eccentricity suggest a longer‐term sensitivity to sea level and orbital variations associated with Milankovitch cycles. Seafloor spreading is considered a small but steady contributor of CO2 to climate cycles on the 100 kyr time scale; however, this assumes a consistent short‐term eruption rate. Pulsing of seafloor volcanic activity may feed back into climate cycles, possibly contributing to glacial/interglacial cycles, the abrupt end of ice ages, and dominance of the 100 kyr cycle.
One‐ and two‐dimensional hybrid simulations of whistler mode waves in a dipole field
Authors: Wu S. , Denton R. E. , Liu K. , Hudson M. K. 
Published: February 2015

AbstractWe simulate whistler mode waves using a hybrid code. There are four species in the simulations, hot electrons initialized with a bi‐Maxwellian distribution with temperature in the direction perpendicular to background magnetic field greater than that in the parallel direction, warm isotropic electrons, cold inertialess fluid electrons, and protons as an immobile background. The density of the hot population is a small fraction of the total plasma density. Comparison between the dispersion relation of our model and other dispersion relations shows that our model is more accurate for lower frequency whistlers than for higher frequency whistlers. Simulations in 2‐D Cartesian coordinates agree very well with those using a full dynamics code. In the 1‐D simulations along the dipole magnetic field, the predicted frequency and wave number are observed. Rising tones are observed in the one‐fourteenth scale simulations that have larger than realistic magnetic field spatial inhomogeneity. However, in the full‐scale 1‐D simulation in a dipole field, the waves are more broadband and do not exhibit rising tones. In the 2‐D simulations in a meridional plane, the waves are generated with propagation approximately parallel to the background magnetic field. However, the wavefronts become oblique as they propagate to higher latitudes. Simulations with different plasma density profiles acrossLshell are performed to study the effect of the background density on whistler propagation.
Development of HF radar inversion algorithm for spectrum estimation (HIAS)
Authors: Hisaki Yukiharu 
Published: February 2015

AbstractA method for estimating ocean wave directional spectra using an HF (high‐frequency) ocean radar was developed. This method represents the development of work conducted in previous studies. In the present method, ocean wave directional spectra are estimated on polar coordinates whose center is the radar position, while spectra are estimated on regular grids. This method can be applied to both single and multiple radar cases. The area for wave estimation is more flexible than that of the previous method. As the signal to noise (SN) ratios of Doppler spectra are critical for wave estimation, we develop a method to exclude low SN ratio Doppler spectra. The validity of the method is demonstrated by comparing results with in situ observed wave data that it would be impossible to estimate by the methods of other groups.
Upper tropospheric ozone production from lightning NOx‐impacted convection: Smoke ingestion case study from the DC3 campaign
Authors: Apel E. C. , Hornbrook R. S. , Hills A. J. , Blake N. J. , Barth M. C. , Weinheimer A. , Cantrell C. , Rutledge S. A. , Basarab B. , Crawford J. , Diskin G. , Homeyer C. R. , Campos T. , Flocke F. , Fried A. , Blake D. R. , Brune W. , Pollack I. , Peischl J. , Ryerson T. , Wennberg P. O. , Crounse J. D. , Wisthaler A. , Mikoviny T. , Huey G. , Heikes B. , O'Sullivan D. , Riemer D. D. 
Published: February 2015

AbstractAs part of the Deep Convective Cloud and Chemistry (DC3) experiment, the National Science Foundation/National Center for Atmospheric Research (NCAR) Gulfstream‐V (GV) and NASA DC‐8 research aircraft probed the chemical composition of the inflow and outflow of two convective storms (north storm, NS, south storm, SS) originating in the Colorado region on 22 June 2012, a time when the High Park wildfire was active in the area. A wide range of trace species were measured on board both aircraft including biomass burning (BB) tracers hydrogen cyanide (HCN) and acetonitrile (ACN). Acrolein, a much shorter lived tracer for BB, was also quantified on the GV. The data demonstrated that the NS had ingested fresh smoke from the High Park fire and as a consequence had a higher VOC OH reactivity than the SS. The SS lofted aged fire tracers along with other boundary layer ozone precursors and was more impacted by lightning NOx (LNOx) than the NS. The NCAR master mechanism box model was initialized with measurements made in the outflow of the two storms. The NS and SS were predicted to produce 11 and 14 ppbv of O3, respectively, downwind of the storm over 2 days. Sensitivity tests revealed that the ozone production potential of the SS was highly dependent on LNOx. Normalized excess mixing ratios, ΔX/ΔCO, for HCN and ACN were determined in both the fire plume and the storm outflow and found to be 7.0 ± 0.5 and 2.3 ± 0.5 pptv ppbv−1, respectively, and 1.4 ± 0.3 pptv ppbv−1 for acrolein in the outflow only.
A reassessment of the integrated impact of tropical cyclones on surface chlorophyll in the western subtropical North Atlantic
Authors: Foltz Gregory R. , Balaguru Karthik , Leung L. Ruby 
Published: February 2015

AbstractThe impact of tropical cyclones on surface chlorophyll concentration is assessed in the western subtropical North Atlantic Ocean during 1998–2011. Previous studies in this area focused on individual cyclones and gave mixed results regarding the importance of tropical cyclone‐induced mixing for changes in surface chlorophyll. Using a more integrated and comprehensive approach that includes quantification of cyclone‐induced changes in mixed layer depth, here it is shown that accumulated cyclone energy explains 22% of the interannual variability in seasonally averaged (June–November) chlorophyll concentration in the western subtropical North Atlantic, after removing the influence of the North Atlantic Oscillation (NAO). The variance explained by tropical cyclones is thus about 70% of that explained by the NAO, which has well‐known impacts in this region. It is therefore likely that tropical cyclones contribute significantly to interannual variations of primary productivity in the western subtropical North Atlantic during the hurricane season.
Gold(I)/Copper(II)‐Cocatalyzed Tandem Cyclization/Semipinacol Reaction: Construction of 6‐Aza/Oxa‐Spiro[4.5]decane Skeletons and Formal Synthesis of (±)‐Halichlorine
Authors: Zhu Dao‐Yong , Zhang Zhen , Mou Xue‐Qing , Tu Yong‐Qiang , Zhang Fu‐Min , Peng Jin‐Bao , Wang Shao‐Hua , Zhang Shu‐Yu 
Published: February 2015

AbstractA simple and efficient strategy for the construction of 6‐aza/oxa‐spiro[4.5]decane skeletons under the cocatalysis of gold(I)/copper(II) was developed, and its potential utility was demonstrated by a formal synthesis of the biologically active marine alkaloid (±)‐halichlorine.magnified image
Copper‐Mediated ortho‐Nitration of Arene and Heteroarene CH Bonds Assisted by an 8‐Aminoquinoline Directing Group
Authors: Liu Jidan , Zhuang Shaobo , Gui Qingwen , Chen Xiang , Yang Zhiyong , Tan Ze 
Published: February 2015

AbstractA copper‐mediated, chelation‐assisted ortho CH bond nitration of benzoic acid derivatives using sodium nitrite as the source of the nitro group has been achieved with the aid of an 8‐aminoquinoline directing group. Selective mono‐ or dinitration can be achieved by simply changing the reaction conditions. The method shows excellent functional group tolerance and provides a novel and straightforward route for the preparation of ortho‐nitrated benzoic acids.magnified image
Copper Chloride‐Catalyzed Aerobic Oxidative Annulation of N‐Furfuryl‐β‐Enaminones:Access to Polysubstituted Pyrroles and Indoles
Authors: Liu Jianchao , Zhang Xiaoting , Peng Hui , Jiang Huanfeng , Yin Biaolin 
Published: February 2015

AbstractCopper chloride‐catalyzed aerobic oxidative annulation of N‐furfuryl‐β‐enaminones provides access to polysubstituted pyrroles and indoles. This protocol involves an unprecedented copper chloride‐catalyzed oxidative chlorination of furan and pyrrole rings with oxygen as the terminal oxidant.magnified image
Localized Template‐Driven Functionalization of Nanoparticles by Dynamic Combinatorial Chemistry
Authors: Nowak Piotr , Saggiomo Vittorio , Salehian Fatemeh , Colomb‐Delsuc Mathieu , Han Yang , Otto Sijbren 
Published: February 2015

AbstractWe have developed a method for the localized functionalization of gold nanoparticles using imine‐based dynamic combinatorial chemistry. By using DNA templates, amines were grafted on the aldehyde‐functionalized nanoparticles only if and where the nanoparticles interacted with the template molecules. Functionalization of the nanoparticles was controlled solely by the DNA template; only amines capable of interacting with DNA were bound to the surface. Interestingly, even though our libraries contained only a handful of simple amines, the DNA sequence influenced their attachment to the surface. Our method opens up new opportunities for the synthesis of multivalent, nanoparticle‐based receptors for biomacromolecules.
Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen‐Doped Carbon Composites For High‐Performance Lithium–Sulfur Battery Cathodes
Authors: Song Jiangxuan , Gordin Mikhail L. , Xu Terrence , Chen Shuru , Yu Zhaoxin , Sohn Hiesang , Lu Jun , Ren Yang , Duan Yuhua , Wang Donghai 
Published: February 2015

AbstractDespite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon‐nanotube‐interpenetrated mesoporous nitrogen‐doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g−1 after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer‐sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm−2) with a high sulfur loading of approximately 5 mg cm−2, which is ideal for practical applications of the lithium–sulfur batteries.
Water‐Soluble Triazabutadienes that Release Diazonium Species upon Protonation under Physiologically Relevant Conditions
Authors: Kimani Flora W. , Jewett John C. 
Published: February 2015

AbstractTriazabutadienes are an understudied structural motif that have remarkable reactivity once rendered water‐soluble. It is shown that these molecules readily release diazonium species in a pH‐dependent manner in a series of buffer solutions with pH ranges similar to those found in cells. Upon further development, we expect that this process will be well suited to cargo‐release strategies and organelle‐specific bioconjugation reactions. These compounds offer one of the mildest ways of generating diazonium species in aqueous solutions.
High‐Contrast Red–Green–Blue Tricolor Fluorescence Switching in Bicomponent Molecular Film
Authors: Kim Hyeong‐Ju , Whang Dong Ryeol , Gierschner Johannes , Lee Chong Han , Park Soo Young 
Published: February 2015

AbstractHighly efficient red–green–blue (RGB) tricolor luminescence switching was demonstrated in a bicomponent solid film consisting of (2Z,2′Z)‐2,2′‐(1,4‐phenylene)bis(3‐(4‐butoxyphenyl)acrylonitrile) (DBDCS) and (2Z,2′Z)‐3,3′‐(2,5‐bis(6‐(9H‐carbazol‐9‐yl)hexyloxy)‐1,4‐phenylene)bis(2‐(3,5‐bis(trifluoromethyl)phenyl)acrylonitrile) (m‐BHCDCS). Reversible RGB luminescence switching with a high ratiometric color contrast (λem=594, 527, 458 nm for red, green, and blue, respectively) was realized by different external stimuli such as heat, solvent vapor exposure, and mechanical force. It was shown that Förster resonance energy transfer in the bicomponent mixture could be efficiently switched on and off through supramolecular control.
Mangankatalysierte Synthese von cis‐β‐Aminosäureestern mittels metallorganischer C‐H‐Aktivierung von Ketiminen
Authors: Liu Weiping , Zell Daniel , John Michael , Ackermann Lutz 
Published: February 2015

AbstractMangankatalysierte C‐H‐Funktionalisierungen von Ketiminen schaffen die Voraussetzung für die Synthese von cis‐β‐Aminosäureestern mittels regio‐ und stereoselektiver Alkenanellierung. Die metallorganische C‐H‐Aktivierung weist eine gute Toleranz gegenüber funktionellen Gruppen auf und liefert hochfunktionalisierte β‐Aminosäurederivate mit großer Substratbreite.
Manganese‐Catalyzed Synthesis of cis‐β‐Amino Acid Esters through Organometallic CH Activation of Ketimines
Authors: Liu Weiping , Zell Daniel , John Michael , Ackermann Lutz 
Published: February 2015

AbstractManganese‐catalyzed CH functionalization reactions of ketimines set the stage for the expedient synthesis of cis‐β‐amino acid esters through site‐ and regioselective alkene annulations. The organometallic CH activation occurred efficiently with high functional group tolerance, delivering densely functionalized β‐amino acid derivatives with ample scope.
Electron‐Induced Hydration of an Alkene: Alternative Reaction Pathways
Authors: Warneke Jonas , Wang Ziyan , Swiderek Petra , Bredehöft Jan Hendrik 
Published: February 2015

AbstractElectron‐induced reactions in condensed mixtures of ethylene and water lead to the synthesis of ethanol, as shown by post‐irradiation thermal desorption spectrometry (TDS). Interestingly, this synthesis is not only induced by soft electron impact ionization similar to a previously observed electron‐induced hydroamination but also, at low electron energy, by electron attachment to ethylene and a subsequent acid/base reaction with water.
Photochemical Internalization of Tamoxifens Transported by a “Trojan‐Horse” Nanoconjugate into Breast‐Cancer Cell Lines
Authors: Theodossiou Theodossis A. , Gonçalves A. Ricardo , Yannakopoulou Konstantina , Skarpen Ellen , Berg Kristian 
Published: February 2015

AbstractPhotochemical internalization (PCI) has shown great promise as a therapeutic alternative for targeted drug delivery by light‐harnessed activation. However, it has only been applicable to therapeutic macromolecules or medium‐sized molecules. Herein we describe the use of an amphiphilic, water‐soluble porphyrin–β‐cyclodextrin conjugate (mTHPP‐βCD) as a “Trojan horse” to facilitate the endocytosis of CD‐guest tamoxifens into breast‐cancer cells. Upon irradiation, the porphyrin core of mTHPP‐βCD expedited endosomal membrane rupture and tamoxifen release into the cytosol, as documented by confocal microscopy. The sustained complexation of mTHPP‐βCD with tamoxifen was corroborated by 2D NMR spectroscopy and FRET studies. Following the application of PCI protocols with 4‐hydroxytamoxifen (4‐OHT), estrogen‐receptor β‐positive (Erβ+, but not ERβ−) cell groups exhibited extensive cytotoxicity and/or growth suspension even at 72 h after irradiation.
Geometric and Electronic Structures of Boron(III)‐Cored Dyes Tailored by Incorporation of Heteroatoms into Ligands
Authors: Sun Lin , Zhang Fan , Wang Xinyang , Qiu Feng , Xue Minzhao , Tregnago Giulia , Cacialli Franco , Osella Silvio , Beljonne David , Feng Xinliang 
Published: February 2015

AbstractComplexation of a boron atom with a series of bidentate heterocyclic ligands successfully gives rise to corresponding BF2‐chelated heteroarenes, which could be considered as novel boron(III)‐cored dyes. These dye molecules exhibit planar structures and expanded π‐conjugated backbones due to the locked conformation with a boron center. The geometric and electronic structures of these BF2 complexes can be tailored by embedding heteroatoms in the unique modes to form positional isomer and isoelectronic structures. The structure–property relationship is further elucidated by studying the photophysical properties, electrochemical behavior and quantum‐chemical calculations.
Exogenous retinoic acid induces digit reduction in opossums (Monodelphis domestica) by disrupting cell death and proliferation, and apical ectodermal ridge and zone of polarizing activity function
Authors: Molineaux Anna C. , Maier Jennifer A. , Schecker Teresa , Sears Karen E. 
Published: February 2015

BackgroundRetinoic acid (RA) is a vitamin A derivative. Exposure to exogenous RA generates congenital limb malformations (CLMs) in species from frogs to humans. These CLMs include but are not limited to oligodactyly and long‐bone hypoplasia. The processes by which exogenous RA induces CLMs in mammals have been best studied in mouse, but as of yet remain unresolved.MethodsWe investigated the impact of exogenous RA on the cellular and molecular development of the limbs of a nonrodent model mammal, the opossum Monodelphis domestica. Opossums exposed to exogenous retinoic acid display CLMs including oligodactly, and results are consistent with opossum development being more susceptible to RA‐induced disruptions than mouse development.ResultsExposure of developing opossums to exogenous RA leads to an increase in cell death in the limb mesenchyme that is most pronounced in the zone of polarizing activity, and a reduction in cell proliferation throughout the limb mesenchyme. Exogenous RA also disrupts the expression of Shh in the zone of polarizing activity, and Fgf8 in the apical ectodermal ridge, and other genes with roles in the regulation of limb development and cell death.ConclusionResults are consistent with RA inducing CLMs in opossum limbs by disrupting the functions of the apical ectodermal ridge and zone of polarizing activity, and driving an increase in cell death and reduction of cell proliferation in the mesenchyme of the developing limb. Birth Defects Research (Part A) 103:225–234, 2015. © 2015 Wiley Periodicals, Inc.
Synthesis and Analysis of Specific Covalent Inhibitors of endo‐Xyloglucanases
Authors: Fenger Thomas Hauch , Brumer Harry 
Published: February 2015

AbstractA series of N‐bromoacetylglycosylamines and bromoketone C‐glycosides were synthesised from complex xyloglucan oligosaccharide (XyGO) scaffolds as specific active‐site affinity labels for endo‐xyloglucanases. Compounds based on XXXG (Xyl3Glc4) and XLLG (Xyl3Glc4Gal2) oligosaccharides exhibited strikingly higher affinities and higher rates of irreversible inhibition than known cellobiosyl and new lactosyl disaccharide congeners when tested with endo‐xyloglucanases from two distinct glycoside hydrolase (GH) families. Intact‐protein mass spectrometry indicated that inactivation with XyGO derivatives generally resulted in a 1:1 labelling stoichiometry. Together, these results indicate that XyGO‐based affinity reagents have significant potential as inhibitors and proteomic reagents for the identification and analysis of diverse xyloglucan‐active enzymes in nature, to facilitate industrial enzyme applications.
Nickel–Aluminum Intermetallic Compounds as Highly Selective and Stable Catalysts for the Hydrogenation of Naphthalene to Tetralin
Authors: Chen Xiao , Ma Yue , Wang Lei , Yang Zonghan , Jin Shaohua , Zhang Liangliang , Liang Changhai 
Published: February 2015

AbstractSelective hydrogenation of naphthalene to tetralin was conducted by using Ni–Al intermetallic compounds (IMCs) prepared by a chemical synthetic route. Ni–Al IMC catalysts achieved a lasting high conversion with 100 % selectivity up to 125 h. During the synthesis process, the Ni–Al IMCs underwent the following phase transformation as a function of the content of the Al source (LiAlH4): Ni(cubic)→Ni3Al(tetragonal)→NiAl(cubic)→Ni2Al3(hexagonal). In the selective hydrogenation of naphthalene, the catalytic activity of NiAl was much higher than that of metallic Ni and other Ni–Al IMCs (Ni3Al and Ni2Al3). The results can be understood by a combination of site isolation and alteration of the electronic structure by chemical bonding. Ni atoms are scattered and spatially isolated by Al atoms, which in turn resists carbon deposition. The findings provide a useful approach to tailor the catalytic properties of transition metals by formation of IMCs, which could be applicable in heterogeneous catalysis.
Tuning the Optical Properties of 2‐Thienylpyridyl Iridium Complexes through Carboranes and Anions
Authors: Zhu Lin , Tang Xiao , Yu Qi , Lv Wen , Yan Hong , Zhao Qiang , Huang Wei 
Published: February 2015

Abstract2‐Thienylpyridyl iridium(III) complexes containing an o‐, m‐, or p‐carboranylvinyl‐2,2′‐bipyridine ligand and various counteranions (denoted o‐PF6, m‐BF4, m‐PF6, m‐SbF6, m‐ClO4, m‐OTf, m‐NO3, m‐BPh4, m‐F, m‐Cl, and p‐PF6) were synthesized by using C‐formyl carboranes as starting materials. The solid‐state structures of o‐PF6, m‐PF6, m‐ClO4, and m‐BF4 showed that the cations form twisted cavities in which the anions are fixed by multiple hydrogen bonds. Anion–hydrogen interactions were investigated for nine m‐carborane‐based complexes with different counteranions. All carborane‐based iridium(III) complexes show similar phosphorescence yields in solution but significantly different emission in the solid state. Anion‐exchange titration and theoretical calculations revealed the relationships between structures and optical properties. The size of the anion and CH⋅⋅⋅X anion–hydrogen bonds strongly influence the phosphorescence quantum yield in the solid state. In particular, the CcarH⋅⋅⋅X hydrogen bonds between the carboranyl unit and the anion play an important role in solid‐state phosphorescence. Complex p‐PF6 was successfully applied in phosphorescence‐lifetime bioimaging owing to its low toxicity and near‐infrared emission.
Thermally Triggered Solid‐State Single‐Crystal‐to‐Single‐Crystal Structural Transformation Accompanies Property Changes
Authors: Li Quan‐Quan , Ren Chun‐Yan , Huang Yang‐Yang , Li Jian‐Li , Liu Ping , Liu Bin , Liu Yang , Wang Yao‐Yu 
Published: February 2015

AbstractThe 1D complex [(CuL0.5H2O)⋅H2O]n (1) (H4L=2,2′‐bipyridine‐3,3′,6,6′‐tetracarboxylic acid) undergoes an irreversible thermally triggered single‐crystal‐to‐single‐crystal (SCSC) transformation to produce the 3D anhydrous complex [CuL0.5]n (2). This SCSC structural transformation was confirmed by single‐crystal X‐ray diffraction analysis, thermogravimetric (TG) analysis, powder X‐ray diffraction (PXRD) patterns, variable‐temperature powder X‐ray diffraction (VT–PXRD) patterns, and IR spectroscopy. Structural analyses reveal that in complex 2, though the initial 1D chain is still retained as in complex 1, accompanied with the Cu‐bound H2O removed and new O(carboxyl)Cu bond forming, the coordination geometries around the CuII ions vary from a distorted trigonal bipyramid to a distorted square pyramid. With the drastic structural transition, significant property changes are observed. Magnetic analyses show prominent changes from antiferromagnetism to weak ferromagnetism due to the new formed Cu1‐O‐C‐O‐Cu4 bridge. The catalytic results demonstrate that, even though both solid‐state materials present high catalytic activity for the synthesis of 2‐imidazolines derivatives and can be reused, the activation temperature of complex 1 is higher than that of complex 2. In addition, a possible pathway for the SCSC structural transformations is proposed.