bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinearities in the Evolutional Distinctions Between El Niño and La Niña Types
Authors: Ashok K. , Shamal M. , Sahai A. K. , Swapna P. 
Published: November 2017

AbstractUsing the HadISST, SODA reanalysis, and various other observed and reanalyzed data sets for the period 1950–2010, we explore nonlinearities in the subsurface evolutional distinctions between El Niño types and La Niña types from a few seasons before the onset. Cluster analysis carried out over both summer and winter suggests that while the warm‐phased events of both types are distinguishable, several cold phased events are clustered together. Further, we apply a joint Self‐Organizing Map (SOM) analysis using the monthly sea surface temperature anomaly (SSTA) and thermocline‐depth anomalies in tropical Pacific (TP). Results reveal that the evolutionary paths of El Niño Modoki (EM) and El Niño (EL) are, broadly, different. Subsurface temperature composites of EL and EM show different onset characteristics. During an EL, warm anomaly in the west spreads eastward along the thermocline and reaches the surface in the east in March–May of year(0). During an EM, warm anomaly already exists in the central tropical Pacific and then reaches the surface in the east in September–November of year(0). Composited SSTAs during La Niña (LN) and La Niña Modoki (LM) are distinguishable only at 80% confidence level, but the composited subsurface temperature anomalies show differences in the location of the coldest anomaly as well as evolution at 90% confidence level. Thus, the El Niño flavor distinction is potentially predictable at longer leads.
On the Loop Current Penetration into the Gulf of Mexico
Authors: Weisberg Robert H. , Liu Yonggang 
Published: November 2017

AbstractThe Gulf of Mexico Loop Current generally intrudes some distance into the Gulf of Mexico before shedding an anticyclonic eddy and retreating back to its more direct entry to exit pathway. The control of this aperiodic process remains only partially known. Here we describe the evolution of the Loop Current throughout the era of satellite altimetry, and offer a mechanistic hypothesis on Loop Current intrusion. As a complement to the known effects of Loop Current forcing on the west Florida shelf circulation, we argue that the west Florida shelf, in turn, impacts the Loop Current evolution. A Self‐Organizing Map analysis shows that anomalous northward penetrations of the Loop Current into the Gulf of Mexico occur when the eastern side of Loop Current is positioned west from the southwest corner of the west Florida shelf, whereas the more direct inflow to outflow route occurs when the eastern side of the Loop Current comes in contact with the southwest corner of the west Florida shelf. In essence, we argue that the west Florida shelf anchors the Loop Current in its direct path configuration and that farther northward penetration into the Gulf of Mexico occurs when such anchoring is released. To test of this hypothesis heuristically, we estimate that the dissipation and buoyancy work due to known Loop Current forcing of the west Florida shelf circulation (when in contact with the southwest corner) may exceed the pressure work required for the Loop Current to advance against the ambient Gulf of Mexico fluid.
Evaluation of Oceanic Surface Observation for Reproducing the Upper Ocean Structure in ECHAM5/MPI‐OM
Authors: Luo Hao , Zheng Fei , Zhu Jiang 
Published: November 2017

AbstractBetter constraints of initial conditions from data assimilation are necessary for climate simulations and predictions, and they are particularly important for the ocean due to its long climate memory; as such, ocean data assimilation (ODA) is regarded as an effective tool for seasonal to decadal predictions. In this work, an ODA system is established for a coupled climate model (ECHAM5/MPI‐OM), which can assimilate all available oceanic observations using an ensemble optimal interpolation approach. To validate and isolate the performance of different surface observations in reproducing air‐sea climate variations in the model, a set of observing system simulation experiments (OSSEs) was performed over 150 model years. Generally, assimilating sea surface temperature, sea surface salinity, and sea surface height (SSH) can reasonably reproduce the climate variability and vertical structure of the upper ocean, and assimilating SSH achieves the best results compared to the true states. For the El Niño‐Southern Oscillation (ENSO), assimilating different surface observations captures true aspects of ENSO well, but assimilating SSH can further enhance the accuracy of ENSO‐related feedback processes in the coupled model, leading to a more reasonable ENSO evolution and air‐sea interaction over the tropical Pacific. For ocean heat content, there are still limitations in reproducing the long time‐scale variability in the North Atlantic, even if SSH has been taken into consideration. These results demonstrate the effectiveness of assimilating surface observations in capturing the interannual signal and, to some extent, the decadal signal but still highlight the necessity of assimilating profile data to reproduce specific decadal variability.
Regional Responses to Black Carbon Aerosols: The Importance of Air‐Sea Interaction
Authors: Gnanadesikan A. , Scott A. A. , Pradal M.‐A. , Seviour W. J. M. , Waugh D. W. 
Published: November 2017

AbstractThe impact of modern black carbon aerosols on climate via their changes in radiative balance is studied using a coupled model where sea surface temperatures (SSTs) are allowed to vary and an atmosphere‐only version of the same model where SSTs are held fixed. Allowing the ocean to respond is shown to have a profound impact on the pattern of temperature change. Particularly, large impacts are found in the North Pacific (which cools by up to 1 K in the coupled model) and in north central Asia (which warms in the coupled simulation and cools in the fixed SST simulation). Neither set of experiments shows large changes in surface temperatures in the Southeast Asian region where the atmospheric burden of black carbon is highest. These results are related to the stabilization of the atmosphere and changes in oceanic heat transport. Over the North Pacific, atmospheric stabilization results in an increase in stratiform clouds. The resulting shading reduces evaporation, freshening the surface layer of the ocean and reducing the inflow of warm subtropical waters. Over the land, a delicate balance between greater atmospheric absorption, shading of the surface and changes in latent cooling of the surface helps to determine whether warming or cooling is seen. Our results emphasize the importance of coupling in determining the response of the climate system to black carbon and suggest that black carbon may play an important role in modulating climate change over the North Pacific.
Heroic Memory: Remembering the Details of Others' Heroism in the Aftermath of a Traumatic Public Event Can Foster Our Own Prosocial Response
Authors: Ford Jaclyn Hennessey , Gaesser Brendan , DiBiase Haley , Berro Tala , Young Liane , Kensinger Elizabeth 
Published: November 2017

SummaryHumans, while not wholly altruistic, will often come together to selflessly support and provide aid to others in need. To date, little attention has been paid to how memory for such positive events in the aftermath of a traumatic event can influence subsequent behavior. The current study examined how the way in which people represent and remember helping events immediately following the 2013 Boston Marathon bombing related to their tendency to support Boston‐related charities in the following months. People who recalled helping‐related events in greater detail reported engaging in more helping behaviors in the following months. The relation between memory narratives and reports of helping behavior six months later has important implications for future work investigating the role of memory‐based mechanisms in citizens' decisions to provide aid in times of collective need.Copyright © 2017 John Wiley & Sons, Ltd.
Generation of Multifunctional Magnetic Nanoparticles with Amplified Catalytic Activities by Genetic Expression of Enzyme Arrays on Bacterial Magnetosomes
Authors: Mickoleit Frank , Schüler Dirk 
Published: November 2017

AbstractDue to their highly regulated biosynthesis, magnetosomes biomineralized by magnetotactic bacteria represent natural magnetic nanoparticles with unique physical and chemical properties. They consist of a magnetite core that is surrounded by a biological membrane and are therefore reminiscent to magnetic “core–shell” nanoparticles. Their usability in many nanotechnological and biomedical applications would be further improved by the introduction of additional catalytic and imaging modalities. Here, a new in vivo strategy is explored for magnetosome display of foreign polypeptides with maximized protein‐to‐particle ratios. Arrays of up to five monomers of the model enzyme glucuronidase GusA plus the additional fluorophore mEGFP are genetically fused as single large hybrid proteins to highly expressed magnetosome protein anchors. In total, about 190 GusA monomers are covalently attached to individual particles. Assuming layers of GusA rows surrounding the particles, the monomers would thus cover up to 90% of the magnetosome surface. The approach generates nanoparticles that exhibit magnetism, fluorescence, and stable catalytic activities, which are stepwise increased with the number of GusA monomers. In summary, multicopy expression of arrayed foreign proteins represents a powerful methodology for the biosynthesis of tailored biohybrid magnetic nanoparticles with several genetically encoded and tunable functionalities.
A Unique Disintegration–Reassembly Route to Mesoporous Titania Nanocrystalline Hollow Spheres with Enhanced Photocatalytic Activity
Authors: Wang Xin , Bai Licheng , Liu Hongyan , Yu Xuefeng , Yin Yadong , Gao Chuanbo 
Published: November 2017

AbstractA novel disintegration–reassembly route is reported for the synthesis of mesoporous TiO2 nanocrystalline hollow spheres with controlled crystallinity and enhanced photocatalytic activity. In this unique synthesis strategy, it is demonstrated that sol–gel‐derived mesoporous TiO2 colloidal spheres can be disintegrated into discrete small nanoparticles that are uniformly embedded in the polymer (polystyrene, PS) matrix by surface‐induced photocatalytic polymerization. Subsequent reassembly of these TiO2 nanoparticles can be induced by an annealing process after further coating of a resorcinol–formaldehyde (RF) resin, which forms self‐supported hollow spheres of TiO2 at the PS/RF interface. The abundant phenolic groups on the RF resin serve as anchoring sites for the TiO2 nanoparticles, thus enable the reassembly of the TiO2 nanoparticles and prevent their sintering during the thermal crystallization process. This unique disintegration–reassembly process leads to the formation of self‐supported TiO2 hollow spheres with relatively large surface area, high crystallinity, and superior photocatalytic activity in dye degradation under UV light irradiation.
Surfactant‐Free β‐Galactosidase Micromotors for “On‐The‐Move” Lactose Hydrolysis
Authors: Maria‐Hormigos Roberto , Jurado‐Sánchez Beatriz , Escarpa Alberto 
Published: November 2017

AbstractSurfactant‐free β‐galactosidase micromotors are explored here as moving biocatalyst for highly efficient lactose hydrolysis from raw milk. The coupling of the hydrolytic properties of such enzyme with the efficient movement of carbon nanotube tubular micromotors results in nearly 100% lactose hydrolysis and two fold removal efficiency as compared with static conditions and with free enzyme. The incorporation of an inner Ni layer allows its reusability to operate in batch mode. The rough micromotor surface area allows the immobilization of a high loading of β‐galactosidase and results in an increase in the enzyme affinity toward lactose. The new micromotor concept opens new avenues for the use of micromotors as moving immobilized biocatalyst to improve the technological process not only in food industry but also in other fields.
The Meeting Point of Carbonaceous Materials and Clays: Toward a New Generation of Functional Composites
Authors: Darder Margarita , Aranda Pilar , Ruiz‐García Cristina , Fernandes Francisco M. , Ruiz‐Hitzky Eduardo 
Published: November 2017

AbstractCarbon and clays are worldwide‐spread natural resources known and used for centuries by humans. In spite of their differences, both have been combined to produce diverse types of functional materials, from conventional pencil cores to advanced hybrid composites. The presence of highly conductive graphene and/or carbon nanotubes allows for their use in applications ranging from elements of electrochemical devices to additives for polymer nanocomposites, pollution adsorbents, or active catalysts. Both top‐down and bottom‐up strategies can be applied to conveniently assemble carbon and clay counterparts. Moreover, such synthetic strategies can be tailored to produce adequate nanostructured materials and/or associate other species. This critical review presents the latest advances on this topic, addressing aspects related to the possibility to produce hybrid materials based on their functionalization capacity.
Hierarchical Multicomponent Inorganic Metamaterials: Intrinsically Driven Self‐Assembly at the Nanoscale
Authors: Levchenko Igor , Bazaka Kateryna , Keidar Michael , Xu Shuyan , Fang Jinghua 
Published: November 2017

AbstractIncreasingly intricate in their composition and structural organization, hierarchical multicomponent metamaterials with nonlinear spatially reconfigurable functionalities challenge the intrinsic constraints of natural materials, revealing tremendous potential for the advancement of biochemistry, nanophotonics, and medicine. Recent breakthroughs in high‐resolution nanofabrication utilizing ultranarrow, precisely controlled ion or laser beams have enabled assembly of architectures of unprecedented structural and functional complexity, yet costly, time‐ and energy‐consuming high‐resolution sequential techniques do not operate effectively at industry‐required scale. Inspired by the fictional Baron Munchausen's fruitless attempt to pull himself up, it is demonstrated that metamaterials can undergo intrinsically driven self‐assembly, metaphorically pulling themselves up into existence. These internal drivers hold a key to unlocking the potential of metamaterials and mapping a new direction for the large‐area, cost‐efficient self‐organized fabrication of practical devices. A systematic exploration of these efforts is presently missing, and the driving forces governing the intrinsically driven self‐assembly are yet to be fully understood. Here, recent progress in the self‐organized formation and self‐propelled growth of complex hierarchical multicomponent metamaterials is reviewed, with emphasis on key principles, salient features, and potential limitations of this family of approaches. Special stress is placed on self‐assembly driven by plasma, current in liquid, ultrasonic, and similar highly energetic effects, which enable self‐directed formation of metamaterials with unique properties and structures.
Implementing Quantum Search Algorithm with Metamaterials
Authors: Zhang Weixuan , Cheng Kaiyang , Wu Chao , Wang Yi , Li Hongqiang , Zhang Xiangdong 
Published: November 2017

AbstractMetamaterials, artificially structured electromagnetic (EM) materials, have enabled the realization of many unconventional EM properties not found in nature, such as negative refractive index, magnetic response, invisibility cloaking, and so on. Based on these man‐made materials with novel EM properties, various devices are designed and realized. However, quantum analog devices based on metamaterials have not been achieved so far. Here, metamaterials are designed and printed to perform quantum search algorithm. The structures, comprising of an array of 2D subwavelength air holes with different radii perforated on the dielectric layer, are fabricated using a 3D‐printing technique. When an incident wave enters in the designed metamaterials, the profile of beam wavefront is processed iteratively as it propagates through the metamaterial periodically. After roundtrips, precisely the same as the efficiency of quantum search algorithm, searched items will be found with the incident wave all focusing on the marked positions. Such a metamaterial‐based quantum searching simulator may lead to remarkable achievements in wave‐based signal processors.
Manufacture of Citronellal by the Rhodium‐Catalyzed Homogeneous Hydrogenation of Neral
Authors: Holz Jens , Doerfelt Stephan , Börner Armin 
Published: November 2017

AbstractThe highly chemoselective hydrogenation of neral affording citronellal is described. The reaction has been conducted with homogeneous rhodium complexes. Among the set of ancillary diphosphane ligands tested, Xantphos was found to be superior. The relevant precatalyst has been generated from neutral metal sources such as Rh(acac)(CO)2 or the carbon monoxide‐free rhodium source Rh(acac)(cod) in the absence of any base. A high activity and chemoselectivity in favor of the desired citronellal is achieved at 0.1 MPa and room temperature. Under the same conditions, geranial is also reduced to citronellal. The addition of carbon monoxide to the hydrogen stream as used in an industrial process is not necessary.magnified image
Enantioselective Reactions Catalyzed by N‐Heterocyclic Carbenes
Authors: Zhao Ming , Zhang Yu‐Tong , Chen Jie , Zhou Ling 
Published: November 2017

AbstractEnantioselective organocatalysis by using N‐heterocyclic carbenes (NHCs) has emerged as a powerful strategy for the construction of complex chiral molecules. Recently, remarkable advances have been made in enantioselective NHC‐catalyzed reactions that involve diverse activation intermediates, such as Breslow intermediates, homoenolate intermediates, α,β‐unsaturated acylazoliums, azolium enolates, and azolium dienolates, which are generated by the nucleophilic addition of NHCs to aldehydes. Furthermore, NHC‐catalyzed reactions that proceed through non‐covalent bonding interactions have also been developed.
Control of N‐Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole‐γ‐Amino Acid Derivatives
Authors: Chen Xiang‐Yu , Xiong Jia‐Wen , Liu Qiang , Li Sun , Sheng He , von Essen Carolina , Rissanen Kari , Enders Dieter 
Published: November 2017

AbstractA strategy to control the switch between a non‐cycloaddition reaction and a cycloaddition reaction of enals, using N‐heterocyclic carbene (NHC) catalyisis, has been developed. The new scalable protocol leads to γ‐amino‐acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities by homo‐Mannich reactions of enals and isatin‐derived ketimines. By simply changing the N‐ketimine substituent to an ortho‐hydroxy phenyl group, the corresponding spirocyclic oxindolo‐γ‐lactams are obtained.
Paläo‐inspirierte Systeme: Haltbarkeit, Nachhaltigkeit und bemerkenswerte Eigenschaften
Authors: Bertrand Loïc , Gervais Claire , Masic Admir , Robbiola Luc 
Published: November 2017

AbstractDie Nachahmung von spezifischen (z. B. mechanischen, optischen und strukturellen) Eigenschaften, die in alten und historischen Systemen beobachtet werden, wird in diesem Kurzaufsatz als Paläo‐Inspiration bezeichnet. Zum Beispiel kann die Bergung in der Archäologie oder Paläontologie zur Identifikation von Materialien dienen, die a posteriori sehr widerstandsfähig gegen Veränderungen sind. Umso ermutigender ist die Tatsache, dass viele historische Materialien mit sanften chemischen Methoden hergestellt wurden, wobei oft nur geringe Energieressourcen und manchmal primitive Fertigungsmittel zur Verfügung standen. In diesem Kurzaufsatz werden historische Systeme als Inspirationsquelle für innovatives Materialdesign im Anthropozän betrachtet.
A Redox‐Activated G‐Quadruplex DNA Binder Based on a Platinum(IV)–Salphen Complex
Authors: Bandeira Stephane , Gonzalez‐Garcia Jorge , Pensa Evangelina , Albrecht Tim , Vilar Ramon 
Published: November 2017

AbstractThere has been increasing interest in the development of small molecules that can selectively bind to G‐quadruplex DNA structures. The latter have been associated with a number of key biological processes and therefore are proposed to be potential targets for drug development. Herein, we report the first example of a reduction‐activated G‐quadruplex DNA binder. We show that a new octahedral platinum(IV)–salphen complex does not interact with DNA in aqueous media at pH 7.4; however, upon addition of bioreductants such as ascorbic acid or glutathione, the compound is readily reduced to the corresponding square planar platinum(II) complex. In contrast to the parent platinum(IV) complex, the in situ generated platinum(II) complex has good affinity for G‐quadruplex DNA.
Gram‐Scale Synthesis of the (−)‐Sparteine Surrogate and (−)‐Sparteine
Authors: Firth James D. , Canipa Steven J. , Ferris Leigh , O'Brien Peter 
Published: November 2017

AbstractAn 8‐step, gram‐scale synthesis of the (−)‐sparteine surrogate (22 % yield, with just 3 chromatographic purifications) and a 10‐step, gram‐scale synthesis of (−)‐sparteine (31 % yield) are reported. Both syntheses proceed with complete diastereocontrol and allow access to either antipode. Since the syntheses do not rely on natural product extraction, our work addresses long‐term supply issues relating to these widely used chiral ligands.
Controlled Sol–Gel Transitions of a Thermoresponsive Polymer in a Photoswitchable Azobenzene Ionic Liquid as a Molecular Trigger
Authors: Wang Caihong , Hashimoto Kei , Tamate Ryota , Kokubo Hisashi , Watanabe Masayoshi 
Published: November 2017

AbstractProducing ionic liquids (ILs) that function as molecular trigger for macroscopic change is a challenging issue. Photoisomerization of an azobenzene IL at the molecular level evokes a macroscopic response (light‐controlled mechanical sol–gel transitions) for ABA triblock copolymer solutions. The A endblocks, poly(2‐phenylethyl methacrylate), show a lower critical solution temperature in the IL mixture containing azobenzene, while the B midblock, poly(methyl methacrylate), is compatible with the mixture. In a concentrated polymer solution, different gelation temperatures were observed in it under dark and UV conditions. Light‐controlled sol–gel transitions were achieved by a photoresponsive solubility change of the A endblocks upon photoisomerization of the azobenzene IL. Therefore, an azobenzene IL as a molecular switch can tune the self‐assembly of a thermoresponsive polymer, leading to macroscopic light‐controlled sol–gel transitions.
Visible‐Light‐Mediated Metal‐Free Hydrosilylation of Alkenes through Selective Hydrogen Atom Transfer for Si−H Activation
Authors: Zhou Rong , Goh Yi Yiing , Liu Haiwang , Tao Hairong , Li Lihua , Wu Jie 
Published: November 2017

AbstractAlthough there has been significant progress in the development of transition‐metal‐catalyzed hydrosilylations of alkenes over the past several decades, metal‐free hydrosilylation is still rare and highly desirable. Herein, we report a convenient visible‐light‐driven metal‐free hydrosilylation of both electron‐deficient and electron‐rich alkenes that proceeds through selective hydrogen atom transfer for Si−H activation. The synergistic combination of the organophotoredox catalyst 4CzIPN with quinuclidin‐3‐yl acetate enabled the hydrosilylation of electron‐deficient alkenes by selective Si−H activation while the hydrosilylation of electron‐rich alkenes was achieved by merging photoredox and polarity‐reversal catalysis.