bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructural controls on the physical and mechanical properties of edifice‐forming andesites at Volcán de Colima, Mexico
Authors: Heap M. J. , Lavallée Y. , Petrakova L. , Baud P. , Reuschlé T. , Varley N. R. , Dingwell D. B.
Published: March 2014

The reliable assessment of volcanic unrest must rest on an understanding of the rocks that form the edifice. It is their microstructure that dictates their physical properties and mechanical behavior and thus the response of the edifice to stress perturbations during unrest. We evaluate the interplay between microstructure and rock properties for a suite of edifice‐forming rocks from Volcán de Colima (Mexico). Microstructural analyses expose (1) a pervasive, isotropic microcrack network, (2) a high, subspherical vesicle density, and (3) a wide vesicle size distribution. This complex microstructure severely impacts their physical and mechanical properties. In detail, porosities are high and range from 8 to 29%. As a consequence, elastic wave velocities, Youngs moduli, and uniaxial compressive strengths are low, and permeabilities are high. All of the rock properties demonstrate a wide range. For example, strength decreases by a factor of 8 and permeability increases by 4 orders of magnitude over the porosity range. Below a porosity of 11–14%, the permeability‐porosity trend follows a power law with a much higher exponent. Microstructurally, this represents a critical vesicle content that efficiently connects the microcrack population and permits a much more direct path through the sample, rather than restricting flow to long and tortuous microcracks. Values of tortuosity inferred from the Kozeny‐Carman permeability model support this hypothesis. However, we find that the complex microstructure precludes a complete description of their mechanical behavior through micromechanical modeling. We urge that the findings of this study be considered in volcanic hazard assessments at andesitic stratovolcanoes.
Zircon U‐Pb geochronology of the Mount Givens Granodiorite: Implications for the genesis of large volumes of eruptible magma
Authors: Frazer Ryan E. , Coleman Drew S. , Mills Ryan D.
Published: March 2014

The Mount Givens Granodiorite, a large pluton in the central Sierra Nevada batholith, California, is similar in area to zoned intrusive suites yet is comparatively chemically and texturally homogenous. New zircon U‐Pb geochronology indicates that the pluton was constructed over at least 7 Ma from 97.92 ± 0.06 Ma to 90.87 ± 0.05 Ma. Combining the new geochronology with the exposed volume of the pluton yields an estimated magma flux of <0.001 km3/a. The geochronologic data are at odds with the previously speculated links between plutons such as the Mount Givens Granodiorite and large‐volume homogeneous ignimbrites (often termed monotonous intermediates). Existing data indicate that large plutons accumulate at rates of ≤0.001 km3/a, 1–2 orders of magnitude less than fluxes calculated for dated monotonous intermediates. If monotonous intermediates are remobilized, erupted plutons accumulated at rates comparable to dated examples, they should preserve a record of zircon growth of up to 10 Ma. Alternatively, the long history of zircon growth recorded in plutons may be erased during the processes of reheating and remobilization that precede supervolcano eruption. However, zircon dissolution modeling, based on hypothetical temperature‐time histories for preeruptive monotonous intermediates, indicates that rejuvenation events would not sufficiently dissolve zircon. We suggest that eruptions of monotonous intermediates occur during high magmatic flux events, leaving little behind in the intrusive rock record, whereas low fluxes favor pluton accumulation.
Rheological transition during large strain deformation of melting and crystallizing metapelites
Authors: Misra Santanu , Burg Jean‐Pierre , Vigneresse Jean‐Louis , Mainprice David
Published: March 2014

Torsion experiments ( =3 × 10−4 s−1) were performed to investigate the large strain (γmax = 15) rheology on quartz‐muscovite aggregate as analogue to pelitic rocks undergoing melting and crystallization during deformation at 300 MPa confining pressure and 750°C temperature. Microstructures reveal four distinct but gradational stages of crystal‐melt interactions during deformation—(a) solid state deformation, (b) initiation and domination of partial melting, (c) simultaneous partial melting and crystallization, and (d) domination of crystallization. The microstructural stages are linked to the rheology of the deforming samples. Partial melting starts at relatively low finite shear strains (γ = 1–3) showing approximately 60% strain softening. At γ = 4–10 the partially molten bulk material shows a steady state flow at low stress. Further crystallization of new crystals at the expense of melt between γ = 10 and 15 causes weak strain hardening until the material fails by developing brittle fractures. The stress exponent (n), calculated at γ = 1, 5, and 10, increases from ∼ 3 to ∼ 43, indicating a transition from power to power law breakdown or exponential flow of the bulk system. Hydrostatic experiments for equivalent times and conditions of the torsion experiments were also conducted to evaluate the reaction kinetics and microstructures under static conditions. The new experimental data establish that partially molten rock does not flow according to a constant strain rate‐dependent power law (steady state) rheology. The rheological transition from strain rate sensitive to strain rate insensitive flow is interpreted as a function of melt‐crystal ratio, their mutual interactions, and the evolution of microstructures in the partially molten rock.
Modeling shear wave splitting due to stress‐induced anisotropy, with an application to Mount Asama Volcano, Japan
Authors: Shelley Adrian , Savage Martha , Williams Charles , Aoki Yosuke , Gurevich Boris
Published: March 2014

We use numerical modeling to investigate the proposed stress‐based origin for changing anisotropy at Mount Asama Volcano, Japan. Stress‐induced anisotropy occurs when deviatoric stress conditions are applied to rocks which are permeated by microcracks and compliant pore space, leading to an anisotropic distribution of open crack features. Changes to the local stress field around volcanoes can thus affect the anisotropy of the region. The 2004 eruption of Mount Asama Volcano coincided with time‐varying shear wave splitting measurements, revealing changes in anisotropy that were attributed to stress changes associated with the eruption. To test this assertion, we create a model that incorporates knowledge of the volcanic stress, ray tracing, and estimation of the anisotropy to produce synthetic shear wave splitting results using a dyke stress model. Anisotropy is calculated in two ways, by considering a basic case of having uniform crack density and a case where the strength of anisotropy is related to dry crack closure from deviatoric stress. Our results show that this approach is sensitive to crack density, crack compliance, and the regional stress field, all of which are poorly constrained parameters. In the case of dry crack closure, results show that modeled stress conditions produce a much smaller degree of anisotropy than indicated by measurements. We propose that the source of anisotropy changes at Asama is tied to more complex processes that may precipitate from stress changes or other volcanic processes, such as the movement of pore fluid.
Three‐dimensional variations in Love and Rayleigh wave azimuthal anisotropy for the upper 800 km of the mantle
Authors: Yuan Kaiqing , Beghein Caroline
Published: March 2014

We present a new mantle model (YB14SHani) of azimuthal anisotropy for horizontally polarized shear waves (SH) in parallel with our previously published vertically polarized shear wave (SV) anisotropy model (YB13SVani). YB14SHani was obtained from higher mode Love wave phase velocity maps with sensitivity to anisotropy down to ~1200 km depth. SH anisotropy is present down to the mantle transition zone (MTZ) with an average amplitude of ~2% in the upper 250 km and ~1% in the MTZ, consistent with YB13SVani. Changes in SV and SH anisotropy were found at the top of the MTZ where olivine transforms into wadsleyite, which might indicate that MTZ anisotropy is due to the lattice‐preferred orientation of anisotropic material. Beneath oceanic plates, SV fast axes become subparallel to the absolute plate motion (APM) at a depth that marks the location of a thermally controlled lithosphere‐asthenosphere boundary (LAB). In contrast, SH anisotropy does not systematically depend on ocean age. Moreover, while upper mantle SV anisotropy is anomalously high in the middle of the Pacific, as seen in radial anisotropy models, SH anisotropy amplitude remains close to the average for other oceans. Based on the depth at which SV fast axes and the APM direction begin to align, we also found that the average thickness of cratonic roots is ~ 250 km, consistent with Yuan and Romanowicz (2010) for North America. Here we add new constraints on the nature of the cratonic LAB and show that it is characterized by changes in both SV and SH anisotropy.
Response of the Bering Sea to 11‐year solar irradiance cycles during the Bølling‐Allerød
Authors: Katsuki Kota , Itaki Takuya , Khim Boo‐Keun , Uchida Masao , Tada Ryuji
Published: April 2014

Previous studies find decadal climate variability possibly related to solar activity, although the details regarding the feedback with the ocean environment and ecosystem remain unknown. Here, we explore the feedback system of solar irradiance change during the Bølling‐Allerød period, based on laminated sediments in the northern Bering Sea. During this period, well‐ventilated water was restricted to the upper intermediate layer, and oxygen‐poor lower intermediate water preserved the laminated sediment. An 11‐year cycle of diatom and radiolarian flux peaks was identified from the laminated interval. Increased fresh meltwater input and early sea‐ice retreat in spring under the solar irradiance maximum follow the positive phase of Arctic Oscillation which impacted the primary production and volume of upper intermediate water production in the following winter. Strength of this 11 year solar irradiance effect might be further regulated by the pressure patterns of Pacific decadal oscillation and/or El Niño‐Southern Oscillation variability.
Coupling dry deposition to vegetation phenology in the Community Earth System Model: Implications for the simulation of surface O3
Authors: Val Martin M. , Heald C. L. , Arnold S. R.
Published: April 2014

Dry deposition is an important removal process controlling surface ozone. We examine the representation of this ozone loss mechanism in the Community Earth System Model. We first correct the dry deposition parameterization by coupling the leaf and stomatal vegetation resistances to the leaf area index, an omission which has adversely impacted over a decade of ozone simulations using both the Model for Ozone and Related chemical Tracers (MOZART) and Community Atmospheric Model‐Chem (CAM‐Chem) global models. We show that this correction increases O3 dry deposition velocities over vegetated regions and improves the simulated seasonality in this loss process. This enhanced removal reduces the previously reported bias in summertime surface O3 simulated over eastern U.S. and Europe. We further optimize the parameterization by scaling down the stomatal resistance used in the Community Land Model to observed values. This in turn further improves the simulation of dry deposition velocity of O3, particularly over broadleaf forested regions. The summertime surface O3 bias is reduced from 30 ppb to 14 ppb over eastern U.S. and 13 ppb to 5 ppb over Europe from the standard to the optimized scheme, respectively. O3 deposition processes must therefore be accurately coupled to vegetation phenology within 3‐D atmospheric models, as a first step toward improving surface O3 and simulating O3 responses to future and past vegetation changes.
Impact of increased water vapor on precipitation efficiency over northern Eurasia
Authors: Ye Hengchun , Fetzer Eric J. , Wong Sun , Behrangi Ali , Olsen Edward T. , Cohen Judah , Lambrigtsen Bjorn H. , Chen Luke
Published: April 2014

This study investigates the relationships among water vapor, precipitation efficiency, precipitation amount, and air temperature anomalies on monthly time scales over northern Eurasia for winter and summer 2003–2010. Daily precipitation and temperature records at 505 historical stations, and atmospheric total precipitable water vapor and relative humidity data from Atmospheric Infrared Sounders, are used for analysis. Results show that higher atmospheric precipitable water associated with warmer temperature directly contributes to winter precipitation amount but has little impact on winter precipitation efficiency. However, accelerated decreasing relative humidity associated with higher temperature is the primary factor in the reduction of precipitation efficiency and precipitation amount regardless of higher precipitable water in summer. This study suggests that there are evident seasonal differences in precipitation trend associated with air temperature changes over the study region. Air temperature modifies a key atmospheric water variable that directly controls precipitation for that particular season.
Seismic monitoring of an Alpine mountain river
Authors: Díaz J. , Ruíz M. , Crescentini L. , Amoruso A. , Gallart J.
Published: March 2014

The Canfranc underground laboratory (LSC), excavated under the Central Pyrenees, is mainly devoted to the study of phenomena which needs “cosmic silence.” It also hosts a geodynamical facility, named Geodyn, which holds an accelerometer, a broadband seismometer, and two high‐resolution laser strainmeters. During the routine processing of the seismic data, we detected an unusual spectral signature in the 2–10 Hz frequency band, which does not correspond to the typical sources of seismic noise and which can also be recognized in the strain records. After checking against meteorological and hydrological data, we can relate those signals to variations in the discharge by the Aragon River, an Alpine‐style river in the southern Pyrenees, located about 400 m from the LSC Geodyn facility. Four main episodes have been identified since early 2011, each lasting 1–2 to 6–8 days. Additionally, a limited number of shorter episodes have also been detected. Three types of river‐generated seismic events have been identified, related respectively to moderate rainfall, snowmelt, and flooding events associated to severe storms. Each of those types has distinctive characteristics which allow monitoring the hydrological events from the analysis of seismic and deformation data. A few previous studies have already described the seismic noise close to rivers with larger discharge or in small‐scale experimental settings, and we are showing here that the so‐called “fluvial seismology” can be useful to study the hydrological evolution of Alpine style streams and may have a potential interest for the civil authorities in charge of the management of hydrological basins.
Behaviors of Ferromagnetic Shape Memory Alloy Ni–Mn–Ga Under Incomplete Magneto‐Mechanical Loading–Unloading Cycles
Authors: Amrollahipour Rasoul , Kadkhodaei Mahmoud , Kameli Parviz
Published: April 2014

In order to investigate the behaviors of ferromagnetic shape memory alloys (FSMAs) under incomplete magneto‐mechanical loading–unloading cycles, a single crystal Ni–Mn–Ga specimen is studied with the use of specially designed and manufactured test equipment. Characterization of the specimen is done, and simple experiments are conducted to approve validity of the findings and measurements by the prepared test rig. Stress–strain responses under different constant magnetic fields as well as strain–magnetic field responses under different amounts of a constant pressure are obtained for several complete and incomplete loading–unloading cycles to investigate behaviors of an FMSA when different kinds of interruptions are imposed in the course of loading or unloading. The so‐called phenomena of strain hardening and return point memory are observed in the alloy, and similarities and differences between interruption during loading and unloading are investigated.
Structure of Zirconium Alloy Powder Coatings Processed by High Voltage Electric Discharge Consolidation
Authors: Grigoryev Evgeny G. , Yu. Lebedeva Lyuba , Khasanov Oleg L. , Olevsky Eugene A.
Published: April 2014

Zirconium alloy powders (Zr + 1% Nb) of spherical and flake forms have been consolidated by high voltage electric discharge processing. The consolidation enabled the fabrication of coatings on ceramic and metallic substrates as well as of freestanding powder components. The experimental dependence of the electric conductivity of the powders of spherical shape and flake shape on the applied pressure has been investigated. The influence of the current pulse amplitude on the final density of the consolidated zirconium powder alloy coatings on ceramic and metallic substrates and of the produced free‐standing powder samples has been analyzed for different applied pressures. The maximum amplitude of the electric current density above, which the consolidation process is unstable and has a nature of blowout has been determined. The conducted metallographic analysis showed the preservation of the microstructure of initial powder particles after the process of high voltage electric discharge consolidation.
Spinel ZnMn2O4 Nanocrystal‐Anchored 3D Hierarchical Carbon Aerogel Hybrids as Anode Materials for Lithium Ion Batteries
Authors: Yin Longwei , Zhang Zhiwei , Li Zhaoqiang , Hao Fengbin , Li Qun , Wang Chengxiang , Fan Runhua , Qi Yongxin
Published: April 2014

To improve the electrochemical performance of spinel ZnMn2O4, i.e., its limited specific capacity, cycling performance, and rate properties, owing to its inherent poor electrical conductivity and large volume changes during lithiation and delithiation processes, spinel ZnMn2O4 nanocrystals are anchored into a three dimensional (3D) porous carbon aerogel (CA) through a facile solution immersion chemical route. The designed 3D spinel ZnMn2O4/CA hybrids display the advantages of both spinel ZnMn2O4 and porous CA: enormous interfacial surface area, connected 3D framework, abundant porosity and high electron transport properties of CA, and electrochemical properties of nanostructured spinel ZnMn2O4 oxide materials. The synthesized novel ZnMn2O4/CA hybrids display a significantly improved electrochemical performance, with a high reversible specific capacity, and high‐rate capability, as well as an excellent cycling performance, superior to that of previously reported ZnMn2O4‐based materials. After 50 cycles, the 50%ZnMn2O4/CA hybrid displays a reversible capacity of 833 mAh g−1 at a current density of 100 mAg‐1, much higher than the theoretical capacity of 784 mAh g−1 for pure spinel ZnMn2O4 materials, corresponding to a Coulombic efficiency of 99.9%. The greatly improved cycle stability, specific capacity, and high rate performance of the ZnMn2O4/CA hybrids can be attributed to the synergistic interaction between spinel‐structured ZnMn2O4 nanoparticles and the 3D interconnected porous CA matrix.
Atomic Structure and Kinetics of NASICON NaxV2(PO4)3 Cathode for Sodium‐Ion Batteries
Authors: Jian Zelang , Yuan Chenchen , Han Wenze , Lu Xia , Gu Lin , Xi Xuekui , Hu Yong‐Sheng , Li Hong , Chen Wen , Chen Dongfeng , Ikuhara Yuichi , Chen Liquan
Published: April 2014

Na3V2(PO4)3 is one of the most important cathode materials for sodium‐ion batteries, delivering about two Na extraction/insertion from/into the unit structure. To understand the mechanism of sodium storage, a detailed structure of rhombohedral Na3V2(PO4)3 and its sodium extracted phase of NaV2(PO4)3 are investigated at the atomic scale using a variety of advanced techniques. It is found that two different Na sites (6b, M1 and 18e, M2) with different coordination environments co‐exist in Na3V2(PO4)3, whereas only one Na site (6b, M1) exists in NaV2(PO4)3. When Na is extracted from Na3V2(PO4)3 to form NaV2(PO4)3, Na+ occupying the M2 site (CN = 8) is extracted and the rest of the Na remains at M1 site (CN = 6). In addition, the Na atoms are not randomly distributed, possibly with an ordered arrangement in M2 sites locally for Na3V2(PO4)3. Na+ ions at the M1 sites in Na3V2(PO4)3 tend to remain immobilized, suggesting a direct M2‐to‐M2 conduction pathway. Only Na occupying the M2 sites can be extracted, suggesting about two Na atoms able to be extracted from the Na3V2(PO4)3 structure.
Synthesis of Fused Cyclopentenones through Palladium‐Catalyzed Cyclization of 2‐Iodoaryl Allenols
Authors: Alcaide Benito , Almendros Pedro , Alonso José M. , Fernández Israel , Khodabakhshi Saeed
Published: April 2014

A versatile strategy for the synthesis of fused cyclopentenones, key structural motifs in biologically relevant compounds such as indenones and indole alkaloids, has been established successfully through regioselective palladium‐catalyzed cyclization of 2‐iodoaryl allenols.

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High‐Performance, Transparent, Dye‐Sensitized Solar Cells for See‐Through Photovoltaic Windows
Authors: Zhang Kun , Qin Chuanjiang , Yang Xudong , Islam Ashraful , Zhang Shufang , Chen Han , Han Liyuan
Published: April 2014

Dye‐sensitized solar cells (DSCs) have attracted great interest as one of the most promising photovoltaic technologies, and transparent DSCs show potential applications as photovoltaic windows. However, the competition between light absorption for photocurrent generation and light transmittance for obtaining high transparency limits the performance of transparent DSCs. Here, transparent DSCs exhibiting a high light transmittance of 60.3% and high energy conversion efficiency (3.66%) are reported. The strategy is to create a cocktail system composed of ultraviolet and near‐infrared dye sensitizers that selectively and efficiently harvest light in the invisible or low‐eye‐sensitivity region while transmitting light in high‐eye‐sensitivity regions. This new design provides a reasonable approach for realizing high efficiency and transparency DSCs that have potential applications as photovoltaic windows.
Ein neuartiges Konzept zur Synthese mehrfach dotierter Goldcluster [(M@AunM′m)Lk]q+
Authors: Puls Arik , Jerabek Paul , Kurashige Wataru , Förster Moritz , Molon Mariusz , Bollermann Timo , Winter Manuela , Gemel Christian , Negishi Yuichi , Frenking Gernot , Fischer Roland A.
Published: April 2014

Heterometalldotierte Goldcluster sind durch nasschemische Synthese schwer zugänglich, und mit Hauptgruppenmetallen oder frühen Übergangsmetallen dotierte Cluster sind rar. Die Verbindungen [M(AuPMe3)11(AuCl)]3+ (M=Pt, Pd, Ni) (1–3), [Ni(AuPPh3)(8–2n)(AuCl)3(AlCp*)n] (n=1, 2) (4, 5) und [Mo(AuPMe3)8(GaCl2)3(GaCl)]+ (6) wurden selektiv durch Transmetallierung von [M(M′Cp*)n] (M=Mo, E=Ga, n=6; M=Pt, Pd, Ni, M′=Ga, Al; n=4) mit [ClAuPR3] (R=Me, Ph) hergestellt und mit Einkristallröntgenbeugung sowie ESI‐MS charakterisiert. Mithilfe von DFT‐Rechnungen wurden die Bindungsverhältnisse analysiert. Die Transmetallierung ist eine wirkungsvolle Syntheseroute hin zu heterometalldotierten Goldclustern, deren Aufbau der 18‐Valenzelektronenregel für das Zentralmetallatom gehorcht und die mit dem Superatomkonzept auf Grundlage des Jellium‐Modells übereinstimmen.
Reversible Re‐programing of Cell–Cell Interactions
Authors: Gabrielse Kari , Gangar Amit , Kumar Nigam , Lee Jae Chul , Fegan Adrian , Shen Jing Jing , Li Qing , Vallera Daniel , Wagner Carston R.
Published: April 2014

The ability to engineer and re‐program the surfaces of cells would provide an enabling synthetic biological method for the design of cell‐ and tissue‐based therapies. A new cell surface‐engineering strategy is described that uses lipid‐chemically self‐assembled nanorings (lipid‐CSANs) that can be used for the stable and reversible modification of any cell surface with a molecular reporter or targeting ligand. In the presence of a non‐toxic FDA‐approved drug, the nanorings were quickly disassembled and the cell–cell interactions reversed. Similar to T‐cells genetically engineered to express chimeric antigen receptors (CARS), when activated peripheral blood mononuclear cells (PBMCs) were functionalized with the anti‐EpCAM‐lipid‐CSANs, they were shown to selectively kill antigen‐positive cancer cells. Taken together, these results demonstrate that lipid‐CSANs have the potential to be a rapid, stable, and general method for the reversible engineering of cell surfaces and cell–cell interactions.
Engineering Multifunctional Capsules through the Assembly of Metal–Phenolic Networks
Authors: Guo Junling , Ping Yuan , Ejima Hirotaka , Alt Karen , Meissner Mirko , Richardson Joseph J. , Yan Yan , Peter Karlheinz , von Elverfeldt Dominik , Hagemeyer Christoph E. , Caruso Frank
Published: April 2014

Metal–organic coordination materials are of widespread interest because of the coupled benefits of inorganic and organic building blocks. These materials can be assembled into hollow capsules with a range of properties, which include selective permeability, enhanced mechanical/thermal stability, and stimuli‐responsiveness. Previous studies have primarily focused on the assembly aspects of metal‐coordination capsules; however, the engineering of metal‐specific functionality for capsule design has not been explored. A library of functional metal–phenolic network (MPN) capsules prepared from a phenolic ligand (tannic acid) and a range of metals is reported. The properties of the MPN capsules are determined by the coordinated metals, allowing for control over film thickness, disassembly characteristics, and fluorescence behavior. Furthermore, the functional properties of the MPN capsules were tailored for drug delivery, positron emission tomography (PET), magnetic resonance imaging (MRI), and catalysis. The ability to incorporate multiple metals into MPN capsules demonstrates that a diverse range of functional materials can be generated.
A Facile Synthesis of Dynamic, Shape‐Changing Polymer Particles
Authors: Klinger Daniel , Wang Cynthia X. , Connal Luke A. , Audus Debra J. , Jang Se Gyu , Kraemer Stephan , Killops Kato L. , Fredrickson Glenn H. , Kramer Edward J. , Hawker Craig J.
Published: April 2014

We herein report a new facile strategy to ellipsoidal block copolymer nanoparticles that exhibit a pH‐triggered anistropic swelling profile. In a first step, elongated particles with an axially stacked lamellae structure are selectively prepared by utilizing functional surfactants to control the phase separation of symmetric polystyrene‐b‐poly(2‐vinylpyridine) (PS‐b‐P2VP) in dispersed droplets. In a second step, the dynamic shape change is realized by cross‐linking the P2VP domains, thereby connecting glassy PS discs with pH‐sensitive hydrogel actuators.
Goldnanopartikel‐gefüllte Polymer‐Nanoreaktoren für Teebeutel‐ ähnliche Katalysatoren
Authors: Mitschang Fabian , Schmalz Holger , Agarwal Seema , Greiner Andreas
Published: April 2014

Polymer‐Nanoröhrchen mit eingeschlossenen Goldnanopartikeln wurden über den “Tubes by Fiber Templates”(TUFT)‐Prozess hergestellt und als Teebeutel‐ähnliches Katalysatorsystem verwendet. Dazu wurden zunächst Poly(L‐lactid)‐stabilisierte Goldnanopartikel synthetisiert und mit freiem Poly(L‐lactid) zu Komposit‐Nanofasern elektrogesponnen. Anschließend wurde das Faservlies aus der Gasphase mit Poly(p‐xylylen) beschichtet, und die inneren Templatfasern wurden durch Pyrolyse entfernt. Die so hergestellten Polymer‐Röhrchen enthielten immobilisierte Goldnanopartikel und zeigten eine hohe katalytische Aktivität bezüglich der hydrolytischen Oxidation von Dimethylphenylsilan sowie der entsprechenden Alkoholyse mit n‐Butanol. Das makroskopische Röhrchenvlies konnte zur Katalyse analog zu einem Teebeutel verwendet werden und zeigte eine hervorragende Wiederverwendbarkeit.
Modular Construction of Dynamic Nucleodendrimers
Authors: Abet Valentina , Evans Robert , Guibbal Florian , Caldarelli Stefano , Rodriguez Raphaël
Published: April 2014

Isoguanosine‐containing dendritic small molecules self‐assemble into decameric nucleodendrimers as observed by 1D NMR spectroscopy, 2D DOSY, and mass spectrometry. In particular, apolar building blocks readily form pentameric structures in acetonitrile while the presence of alkali metals promotes the formation of stable decameric assemblies with a preference for cesium ions. Remarkably, co‐incubation of guanosine and isoguanosine‐containing nucleodendrons results in the formation of decameric structures in absence of added salts. Further analysis of the mixture indicated that guanosine derivatives facilitate the formation, but are not involved in decameric structures; a process reminiscent of molecular crowding. This molecular system provides a powerful canvas for the rapid and modular assembly of polyfunctional dendritic macromolecules.
Scalable Synthesis of Interconnected Porous Silicon/Carbon Composites by the Rochow Reaction as High‐Performance Anodes of Lithium Ion Batteries
Authors: Zhang Zailei , Wang Yanhong , Ren Wenfeng , Tan Qiangqiang , Chen Yunfa , Li Hong , Zhong Ziyi , Su Fabing
Published: April 2014

Despite the promising application of porous Si‐based anodes in future Li ion batteries, the large‐scale synthesis of these materials is still a great challenge. A scalable synthesis of porous Si materials is presented by the Rochow reaction, which is commonly used to produce organosilane monomers for synthesizing organosilane products in chemical industry. Commercial Si microparticles reacted with gas CH3Cl over various Cu‐based catalyst particles to substantially create macropores within the unreacted Si accompanying with carbon deposition to generate porous Si/C composites. Taking advantage of the interconnected porous structure and conductive carbon‐coated layer after simple post treatment, these composites as anodes exhibit high reversible capacity and long cycle life. It is expected that by integrating the organosilane synthesis process and controlling reaction conditions, the manufacture of porous Si‐based anodes on an industrial scale is highly possible.
Designing p‐Type Semiconductor–Metal Hybrid Structures for Improved Photocatalysis
Authors: Wang Lili , Ge Jing , Wang Ailun , Deng Mingsen , Wang Xijun , Bai Song , Li Rui , Jiang Jun , Zhang Qun , Luo Yi , Xiong Yujie
Published: April 2014

A practical strategy is proposed to facilitate the migration of holes in semiconductor (the low rate of which limits photocatalytic efficiency) by taking advantage of the Schottky barrier between p‐type semiconductor and metal. A high work function is found to serve as an important selection rule for building such desirable Schottky junction between semiconductor surface facets and metal. The intrinsic charge spatial distribution has to be taken into account when selecting the facets, as it results in accumulation of photoexcited electrons and holes on certain semiconductor facets. Importantly, the facets have a high work function, the same characteristic required for the formation of Schottky junction in a p‐type semiconductor–metal hybrid structure. As a result, the semiconductor crystals in the hybrid design may be better enclosed by single facets with high work function, so as to synergize the two effects: Schottky barrier versus charge spatial separation.
Cyclic CO2 capture of carbide slag modified by pyroligneous acid in calcium looping cycles
Authors: Liu Changtian , Li Yingjie , Sun Rongyue , Wu Shuimu
Published: April 2014

Carbide slag is a kind of industrial waste obtained in the production of acetylene that is the raw material of polyvinyl chloride in chlor‐alkali plants. The carbide slag modified by pyroligneous acid was proposed as a CO2 sorbent at high temperature. The CO2 capture capacity of the carbide slag modified by pyroligneous acid in the calcium looping cycles was investigated in a thermogravimetric analyzer and a dual fixed‐bed reactor. The modified carbide slag exhibits better CO2 capture capacity than the carbide slag. The modified carbide slag releases the organic substances whose combustion leads to a drop in CO2 capture capacity. The pre‐calcination treatment of the modified carbide slag at 400 °C before the first calcination was employed to avoid the combustion of the organic substances. The pre‐calcined modified carbide slag exhibits higher carbonation conversions, compared with the modified carbide slag without pre‐calcination treatment. The pre‐calcined modified carbide slag achieves higher carbonation conversions at 950 °C and shows larger surface area and pore volume than the modified carbide slag in the cycles. It indicates that combining the modification by pyroligneous acid with the pre‐calcination treatment apparently improves cyclic CO2 capture capacity of the carbide slag in the multiple cycles. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Kinetic of lactic acid production from sugarcane juice using Lactobacillus plantarum NCIM 2912
Authors: Sikder Jaya , Chakraborty Sudip , Sharma Vedant , Drioli Enrico
Published: April 2014

Kinetics of batch fermentation of sugarcane juice for lactic acid production by Lactobacillus plantarum NCIM 2912 under anaerobic conditions has been analyzed. Lactic acid fermentation with this bacterium is found to be homolactic. Kinetics of cell growth and multiplication fits reasonably into Monod's kinetic model, and the Luedeking–Piret equation has been found to reliably predict kinetics of lactic acid production. The kinetic parameters have been determined on the basis of experimental data using a program developed in Microsoft Excel and matlab. The value of the key kinetic constants estimated is the maximum specific growth rate (μmax), 0.92/h; substrate limitation constant (Ks), 44.1 g/L; growth‐associated constant (α), 10.08 g/g; and nongrowth‐associated constant (β), 0.92 g/g h for lactic acid production. Maximum lactic acid concentration and productivity were found to be 89.5 g/L and 1.243 g/L h, respectively. Kinetic analysis thus revealed that lactic acid production is predominantly growth associated. Effect of substrate inhibition has been observed to be relatively small. Stoichiometric parameters have been estimated to be the maximum product yield coefficient YPS, 0.83 g, lactic acid/g sucrose and average cell mass yield coefficient Yxs, 0.47. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Investigation of antifungal and antibacterial effects of fabric padded with highly stable selenium nanoparticles
Authors: Yip Joanne , Liu Liwei , Wong Ka‐Hing , Leung Polly H. M. , Yuen Chun‐Wah Marcus , Cheung Mei‐Chun
Published: April 2014

In this article, highly stable selenium nanoparticles (SeNPs) were padded onto fabric to obtain, for the first time, antifungal and antibacterial fabric. SeNPs are prepared from a simple food‐grade redox system by using polysaccharide–protein complexes (PSPs) isolated from the mushroom sclerotia of Pleurotus tuber‐regium (tiger milk mushroom) as a modifier or stabilizer. The novel PSP–SeNPs are highly stable, size‐controllable, and water‐dispersible. Different amounts of PSP–SeNPs were applied onto fabric by using the pad–dry–cure method. It was found that the fabric treated with PSP–SeNPs can inhibit more than 99.7% of Trichophyton rubrum growth over a testing period of 7 days. The inhibition of Staphylococcus is effective in the first 12 h. The fabric treated with PSP–SeNPs is a promising material that can potentially be used inside shoes as insoles or shoe material to reduce the possibility of tinea pedis infection usually caused by the T. rubrum fungus. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40728.
Polyethyleneimine coating of magnetic particles increased the stability of an immobilized diglycosidase
Authors: Minig Marisol , Mazzaferro Laura S. , Capecce Agostina , Breccia Javier D.
Published: April 2014

The diglycosidase, α‐rhamnosyl‐β‐glucosidase, from Acremonium sp. DSM24697 was immobilized by adsorption and cross‐linking onto polyaniline–iron (PI) particles. The immobilization yield and the immobilization efficiency were relatively high, 31.2% and 8.9%, respectively. However, the heterogeneous preparation showed lower stability in comparison with the soluble form of the enzyme in operational conditions at 60 °C. One parameter involved in the reduced stability of the heterogeneous preparation was the protein metal–catalyzed oxidation achieved by iron traces supplied from the support. To overcome the harmful effect, iron particles were coated with polyethyleneimine (PEI; 0.84 mg/g) previously for the immobilization of the catalyst. The increased stability of the catalyst was correlated with the amount of iron released from the support. Under operational conditions, the uncoated particles lost between 76% and 52% activity after two cycles of reuse, whereas the PEI‐coated preparation reduced 45–28% activity after five cycles of reuse in the range of pH 5.0–10, respectively. Hence, polymer coating of magnetic materials used as enzyme supports might be an interesting approach to improve the performance of biotransformation processes.
Nutraceuticals and regulation of adipocyte life: Premises or promises
Authors: Colitti Monica , Grasso Stefano
Published: April 2014

Obesity is the actual worldwide health threat, that is associated with an increased number of metabolic disorders and diseases. Following the traditional hypothesis stating that in obesity hypertrophic adipocytes trigger the adipose tissue hyperplasia, strategies to treat obesity have increased fat researches of the molecular processes that achieve adipocyte enlargement and formation that finally increase body fat mass. Moreover, a new cell type was recently identified, the “brite” adipocyte that presents a unique gene expression profile of compared to both brown and white adipocytes. Therapies against obesity, targeting these cells and their pathways, would include the induction of lipolysis and apoptosis or the inhibition of differentiation and adipogenesis. However, it should be noted that both the increase of adipocyte size and number take place in association with positive energy balance. According to the adipose tissue expansion hypothesis, adipogenesis could be related with improved metabolic health of obese people, taking back the adipose mass to a traditionally site of lipid storage. Furthermore, new perspectives in fat biology suggest that the conversion of white‐to‐brown adipocytes and their metabolism could be exploited for the development of therapeutic approaches against obesity‐associated diseases and for the regulation of energy balance. Drugs currently available to treat obesity generally have unpleasant side effects. A novel promising approach is the usage of dietary supplements and plant products that could interfere on the life cycle of adipocyte. Here, various dietary bioactive compounds that target different stages of adipocyte life cycle and molecular and metabolic pathways are reviewed. © 2014 BioFactors, 40(4):398–418, 2014
A retrospective analysis of the effect of intraoperative opioid dose on cancer recurrence after non‐small cell lung cancer resection
Authors: Cata Juan P. , Keerty Visesh , Keerty Dinesh , Feng Lei , Norman Peter H. , Gottumukkala Vijaya , Mehran John R. , Engle Mitchel
Published: April 2014

Preclinical studies have demonstrated that opioid receptor agonists increase the rate of non‐small cell lung cancer (NSCLC) growth and metastasis. Following institutional review board approval, we retrieved data on 901 patients who underwent surgery for NSCLC at MD Anderson Cancer Center. Comprehensive demographics, intraoperative data, and recurrence‐free survival (RFS) and overall survival (OS) at 3 and 5 years were obtained. Cox proportional analyses were conducted to assess the association between intraoperative opioid exposure and RFS and OS. The median intraoperative fentanyl equivalents dosage was 10.15 μg/kg. The multivariate analysis by stage indicated that a trend toward significance for opioid consumption as a risk factor in stage I patients (P = 0.053). No effect was found on RFS for stage II or III patients. Alternatively, opioid consumption was a risk factor for OS for stage I patients (P = 0.036), whereas no effect was noted for stage II or III patients. Intraoperative opioid use is associated with decreased OS in stage I but not stage II–III NSCLC patients. Until randomized controlled studies explore this association further, opioids should continue to be a key component of balanced anesthesia.
A role for G‐CSF and GM‐CSF in nonmyeloid cancers
Authors: Aliper Alexander M. , Frieden‐Korovkina Victoria P. , Buzdin Anton , Roumiantsev Sergey A. , Zhavoronkov Alex
Published: April 2014

Granulocyte colony‐stimulating factor (G‐CSF) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) modulate progression of certain solid tumors. The G‐CSF‐ or GM‐CSF‐secreting cancers, albeit not very common are, however, among the most rapidly advancing ones due to a cytokine‐mediated immune suppression and angiogenesis. Similarly, de novo angiogenesis and vasculogenesis may complicate adjuvant use of recombinant G‐CSF or GM‐CSF thus possibly contributing to a cancer relapse. Rapid diagnostic tools to differentiate G‐CSF‐ or GM‐CSF‐secreting cancers are not well developed therefore hindering efforts to individualize treatments for these patients. Given an increasing utilization of adjuvant G‐/GM‐CSF in cancer therapy, we aimed to summarize recent studies exploring their roles in pathophysiology of solid tumors and to provide insights into some complexities of their therapeutic applications.
MnO2 Nanoflower Arrays with High Rate Capability for Flexible Supercapacitors
Authors: Li Wenyao , Xu Kaibing , Li Bo , Sun Jianqing , Jiang Feiran , Yu Zhishui , Zou Rujia , Chen Zhigang , Hu Junqing
Published: April 2014

Large‐area α‐MnO2 nanoflower arrays are synthesized by using a facile and template‐free electrochemical deposition on flexible graphite paper. These nanoflower arrays exhibit a high specific capacitance of 314 F g−1 at a current density of 1 A g−1 with remarkable rate capability (61.1 % retention at 40 A g−1) and excellent cycle stability. Furthermore, the fabricated flexible symmetric supercapacitor also displays good performance and flexibility.
A Facile Synthesis of Pechmann Dyes
Authors: Hopf Henning , Jones Peter G. , Nicolescu Alina , Bicu Elena , Birsa Lucian M. , Belei Dalila
Published: April 2014

A facile synthesis of Pechmann dyes has been accomplished by the reaction of substituted N‐phenacyl‐4‐dimethylaminopyridinium halides with dimethyl maleate in the presence of DBU. Based on a related 4‐DMAP elimination product and an isolated monolactone intermediate a reaction mechanism has been proposed. The scope of this synthetic method is determined by the availability of α‐haloaroyl or heteroaroyl derivatives. DBU=1,8‐diazabicycloundec‐7‐ene, DMAP=4‐dimethylaminopyridine.
Clinical Utility and Prognostic Significance of Measuring Troponin I Levels in Patients Presenting to the Emergency Room With Atrial Fibrillation
Authors: Gupta Kamal , Pillarisetti Jayasree , Biria Mazda , Pescetto Micah , Abu‐Salah Tareq M. , Annapureddy Chandra , Ryschon Kay , Dawn Buddhadeb , Lakkireddy Dhanunjaya
Published: April 2014

Background

The clinical significance of mildly elevated troponins in patients presenting to the emergency room (ER) with atrial fibrillation (AF) is not well understood.

Hypothesis

We hypothesized that mildly elevated troponin in these patients is associated with adverse cardiovascular outcomes.

Methods

In a multi‐center, retrospective study, 662 patients with AF were divided into 3 groups based on troponin levels: group 1, mildly elevated; group 2, normal; and group 3, troponin not measured. Primary outcome was the combined endpoint of all‐cause mortality and myocardial infarction (MI) at one year.

Results

Levels of TnI were measured in 503 (76%) patients. They were elevated in 220 patients (33%, group 1; mean, 0.56 ng/mL), normal in 283 patients (43%, group 2), and not measured in 159 patients (24%, group 3). Significantly more cardiac testing was done at index hospitalization in group 1 (50%) compared with groups 2 and 3 (28% and 29%, P ≤ 0.001) and in the following year (29%, vs 20% and 17%, P = 0.02). Group 1 had more positive tests (62%) compared with groups 2 and 3 (25% and 43%, P ≤ 0.001). Group 1 had a significantly higher occurrence of the primary endpoint (22%, vs 10% and 15%, P = 0.002), driven primarily by a higher incidence of MI in group 1 (7%, vs 1% and 2%, P = 0.001).

Conclusions

Troponin levels are routinely checked in a majority of patients presenting to the emergency department with AF. Even mildly elevated TnI is associated with a greater incidence of coronary artery disease on diagnostic testing and a higher 1‐year incidence of MI.
A nodes scheduling model based on Markov chain prediction for big streaming data analysis
Authors: Zhang Qingchen , Chen Zhikui , Yang Laurence T.
Published: April 2014

Streaming data analysis is an important part of big data processing. However, streaming data is difficult to be analyzed and processed in real time because of the rapid data arriving speed and huge size of data set in stream model. The paper proposes a nodes scheduling model based on Markov chain prediction for analyzing big streaming data in real time by following three steps: (i) construct data state transition graph using Markov chain to predict the varying trend of big streaming data; (ii) choose appropriate cloud computing nodes to process big streaming data depending on the predicted result of the data state transition graph; and (iii) assign big streaming data to these computing nodes using the load balancing theory, which ensures that all subtasks are accomplished synchronously. Experiments demonstrate that the proposed scheduling algorithm can fast process big streaming data effectively. Copyright © 2014 John Wiley & Sons, Ltd.
The chicken left right organizer has nonmotile cilia which are lost in a stage‐dependent manner in the talpid3 ciliopathy
Authors: Stephen Louise A. , Johnson Edward J. , Davis Gemma M. , McTeir Lynn , Pinkham Jamie , Jaberi Neema , Davey Megan G.
Published: April 2014

Motile cilia are an essential component of the mouse, zebrafish, and Xenopus laevis Left Right Organizers, generating nodal flow and allowing the reception and transduction of mechanosensory signals. Nonmotile primary cilia are also an important component of the Left Right Organizer's chemosensory mechanism. It has been proposed in the chicken that signaling in Hensen's node, the Left Right Organizer of the chicken, is independent of cilia, based on a lack of evidence of motile cilia or nodal flow. It is speculated that the talpid3 chicken mutant, which has normal left–right patterning despite lacking cilia at many stages of development, is proof of this hypothesis. Here, we examine the evidence for cilia in Hensen's node and find that although cilia are present; they are likely to be immotile and incapable of generating nodal flow. Furthermore, we find that early planar cell polarity patterning and ciliogenesis is normal in early talpid3 chicken embryos. We conclude that patterning and development of the early talpid3 chicken is normal, but not necessarily independent of cilia. Although it appears that Hensen's node does not require motile cilia or the generation of motile flow, there may remain a requirement for cilia in the transduction of SHH signaling. genesis 52:600–613, 2014. © 2014 The Authors. Genesis Published by Wiley Periodicals, Inc.