bluuebunny/crossref_metadata_2025_split huggingface dataset:
Turning ABO3 Antiferroelectrics into Ferroelectrics: Design Rules for Practical Rotation‐Driven Ferroelectricity in Double Perovskites and A3B2O7 Ruddlesden‐Popper Compounds
Authors: Mulder Andrew T. , Benedek Nicole A. , Rondinelli James M. , Fennie Craig J. 
Published: May 2013

AbstractFerroic transition metal oxides, which exhibit spontaneous elastic, electrical, magnetic, or toroidal order, exhibit functional properties that find use in ultrastable solid‐state memories, sensors, and medical imaging technologies. To realize multifunctional behavior, where one order parameter can be coupled to the conjugate field of another order parameter, however, requires a common microscopic origin for the long‐range order. Here, a complete theory is formulated for a novel form of ferroelectricity, whereby a spontaneous and switchable polarization emerges from the destruction of an antiferroelectric state due to octahedral rotations and ordered cation sublattices. A materials design framework is then constructed based on crystal‐chemistry descriptors rooted in group theory, which enables the facile design of artificial oxides with large electric polarizations, P, simultaneous with small energetic switching barriers between +P and ‐P. The theory is validated with first principles density functional calculations on more than 16 perovskite‐structured oxides, illustrating it could be operative in any materials classes exhibiting two‐ or three‐dimensional corner‐connected octahedral frameworks. The principles governing materials selection of the “layered” systems are shown to originate in the lattice dynamics of the A cation displacements stabilized by the pervasive BO6 rotations of single phase ABO3 materials, whereby the latter distortions govern the optical band gaps, magnetic order, and critical transition temperatures. This approach provides the elusive route to the practical control of octahedral rotations, and hence, a wide range of functional properties, with an applied electric field.
Optical density as a probe of carbon nanotubes dispersion in polymers
Authors: Combessis Anthony , Mazel Christelle , Maugin Melek , Flandin Lionel 
Published: May 2013

ABSTRACTThe dispersion state of composite materials is known to primarily govern their macroscopic properties. With nanoscopic fillers tiny fluctuations in the interactions among particles may even become the prominent parameter. In this article, the dispersion of carbon nanotubes within a polymer was studied by means of UV–visible spectroscopy and transmitting light microscopy. With thin films, it was found that all the measured absorbances obey a parallel model between the dispersed and the aggregated phases. A method could thus be proposed and validated to gain micrographies of the optical densities within the samples. The Beer–Lambert law was applied to the description of this solid/solid structure, leading to an extinction coefficient for carbon nanotubes comparable to that proposed in solutions. In conclusion, it is shown that one can obtain valuable information from the dispersed phase in optical micrographies, especially the effective filler concentration and a dispersion index in agreement with the literature. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1778–1786, 2013
Mechanical and fracture properties of halloysite nanotube reinforced vinyl‐ester nanocomposites
Authors: Alhuthali Abdullah , Low It‐Meng 
Published: May 2013

ABSTRACTThe mechanical and fracture properties of vinyl‐ester composites reinforced with halloysite nanotubes have been investigated. Enhancements in toughness are attributed to crack bridging, deflection, and localized plastic deformation, while strength improvements can be attributed to the large aspect ratio of fillers, favorable interfacial adhesion and dispersion, and inter‐tubular interaction. Comparisons of experimental data on elastic modulus and mathematical models for predicting particulate polymer composites have verified the models of Paul and Guth. The aspect ratio of fillers and the degree of interfacial adhesion are crucial factors in the prediction of elastic modulus in these polymer nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1716–1725, 2013
Linking human activity and ecosystem condition to inform marine ecosystem based management
Authors: Menzel Susanne , Kappel Carrie V. , Broitman Bernardo R. , Micheli Fiorenza , Rosenberg Andrew A. 
Published: May 2013

ABSTRACTThere is growing consensus that integrated marine management is needed. However, implementation of ecosystem‐based management (EBM) faces major operational challenges, including accurately delineating the links between ecosystem components and benefits to humans, and quantifying trade‐offs associated with different management decisions.It is suggested using human activity level as an indicator of the benefit provided by marine ecosystems at a certain location in comparison with other locations and establishing links between human activity levels and ecological conditions.This approach allows for the determination of what ecological conditions may provide the greatest human benefits and thus may be targets for management action.This approach is used to investigate the link between scuba diving in the Monterey Bay area, California, USA, and different ecological characteristics of kelp forests. Diving intensity levels correlate with kelp persistence, suggesting that kelp persistence may be used as an indicator of benefits from diving and for evaluating the impact of potentially competing activities through their effects on kelp.Overall, an operational definition of marine ecosystem services is provided and it is suggested that this method could be extended to a suite of different activities and systems and thus may become useful in considering trade‐offs among different activities that depend upon the same ecosystem. Copyright © 2013 John Wiley & Sons, Ltd.
Microgravity and Ground‐penetrating Radar Investigations of Subsurface Features at the St Catherine's Monastery, Slovakia
Authors: Panisova Jaroslava , Fraštia Marek , Wunderlich Tina , Pašteka Roman , Kušnirák David 
Published: May 2013

ABSTRACTThe ruins of the St Catherine's monastery complex, the largest sacral ruins in Slovakia, are an important example of Slovak cultural heritage. The Franciscan monastery was a famous site of religious significance due to the legends describing the apparitions of St Catherine. The preservation project of the monastery remains started in 1994. As a part of this project, complex historical, archaeological, anthropological and geophysical research has been conducted at the site since 1997. Microgravity and ground‐penetrating radar (GPR) surveys were carried out in the nave of the former church in order to reveal the position of three aristocratic crypts that served as burial places for the members or higher society in the seventeenth and eighteenth centuries. In the microgravity data processing, a novel method for the calculation of the building correction was employed, where the gravitational effect of the church is calculated using a polyhedral model of the building created from photographs with a special photogrammetric software. Several gravity anomalies were found in the residual Bouguer anomaly map. Semi‐automated interpretation techniques including the Euler deconvolution and harmonic inversion have been used to investigate the depth and size of anomalous sources. Results from 36 GPR profiles obtained by a 400 MHz antenna were visualized in the form of horizontal time‐slices and vertical time‐sections. These images indicate anomalous reflections suggesting potential archaeological targets. Integrated interpretation of results from both geophysical methods has confirmed the presence of a known aristocratic crypt excavated in 2001, as well as two other crypts predicted from historical archives. The combination of microgravity and GPR surveys has proved to be a very effective and non‐destructive tool for archaeological research. Copyright © 2013 John Wiley & Sons, Ltd.
Large Zeolite H‐ZSM‐5 Crystals as Models for the Methanol‐to‐Hydrocarbons Process: Bridging the Gap between Single‐Particle Examination and Bulk Catalyst Analysis
Authors: Hofmann Jan P. , Mores Davide , Aramburo Luis R. , Teketel Shewangizaw , Rohnke Marcus , Janek Jürgen , Olsbye Unni , Weckhuysen Bert M. 
Published: May 2013

AbstractThe catalytic, deactivation, and regeneration characteristics of large coffin‐shaped H‐ZSM‐5 crystals were investigated during the methanol‐to‐hydrocarbons (MTH) reaction at 350 and 500 °C. Online gas‐phase effluent analysis and examination of retained material thereof were used to explore the bulk properties of large coffin‐shaped zeolite H‐ZSM‐5 crystals in a fixed‐bed reactor to introduce them as model catalysts for the MTH reaction. These findings were related to observations made at the individual particle level by using polarization‐dependent UV‐visible microspectroscopy and mass spectrometric techniques after reaction in an in situ microspectroscopy reaction cell. Excellent agreement between the spectroscopic measurements and the analysis of hydrocarbon deposits by means of retained hydrocarbon analysis and time‐of‐flight secondary‐ion mass spectrometry of spent catalyst materials was observed. The obtained data reveal a shift towards more condensed coke deposits on the outer zeolite surface at higher reaction temperatures. Zeolites in the fixed‐bed reactor setup underwent more coke deposition than those reacted in the in situ microspectroscopy reaction cell. Regeneration studies of the large zeolite crystals were performed by oxidation in O2/inert gas mixtures at 550 °C. UV‐visible microspectroscopic measurements using the oligomerization of styrene derivatives as probe reaction indicated that the fraction of strong acid sites decreased during regeneration. This change was accompanied by a slight decrease in the initial conversion obtained after regeneration. H‐ZSM‐5 deactivated more rapidly at higher reaction temperature.
Organic–Inorganic Hybrid Supermicroporous Iron(III) Phosphonate Nanoparticles as an Efficient Catalyst for the Synthesis of Biofuels
Authors: Pramanik Malay , Bhaumik Asim 
Published: May 2013

AbstractHere we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP‐1‐3, HFeP‐1‐2, and HFeP‐1‐4) with different FeIII‐to‐organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene‐1,3,5‐triphosphonic acid and iron(III) chloride under acidic conditions (pH≈4.0). Powder X‐ray diffraction, N2 sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA‐DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P(2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP‐1‐3 by using the MAUD program. The unit cell parameters are a=8.749(1), b=8.578(1), c=17.725(3) Å; α=104.47(3), β=97.64(1), γ=113.56(3)°; and V=1013.41 Å3. With these crystal parameters, we proposed an 24‐membered‐ring open framework structure for HFeP‐1. Compound HFeP‐1‐3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer–Emmett–Telller (BET) surface area of 556 m2g−1 and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions.
Thiol–Yne Click Reactions on Alkynyl–Dopamine‐Modified Reduced Graphene Oxide
Authors: Kaminska Izabela , Qi Wang , Barras Alexandre , Sobczak Janusz , Niedziolka‐Jonsson Joanna , Woisel Patrice , Lyskawa Joel , Laure William , Opallo Marcin , Li Musen , Boukherroub Rabah , Szunerits Sabine 
Published: May 2013

AbstractThe large‐scale preparation of graphene is of great importance due to its potential applications in various fields. We report herein a simple method for the simultaneous exfoliation and reduction of graphene oxide (GO) to reduced GO (rGO) by using alkynyl‐terminated dopamine as the reducing agent. The reaction was performed under mild conditions to yield rGO functionalized with the dopamine derivative. The chemical reactivity of the alkynyl function was demonstrated by post‐functionalization with two thiolated precursors, namely 6‐(ferrocenyl)hexanethiol and 1H,1H,2H,2H‐perfluorodecanethiol. X‐ray photoelectron spectroscopy, UV/Vis spectrophotometry, Raman spectroscopy, conductivity measurements, and cyclic voltammetry were used to characterize the resulting surfaces.
Total Syntheses of (±)‐Fawcettimine, (±)‐Fawcettidine, (±)‐Lycoflexine, and (±)‐Lycoposerramine‐Q
Authors: Itoh Naoya , Iwata Takashi , Sugihara Hiromi , Inagaki Fuyuhiko , Mukai Chisato 
Published: May 2013

AbstractThe total syntheses of four fawcettimine‐related Lycopodium alkaloids, (±)‐fawcettimine, (±)‐fawcettidine, (±)‐lycoposerramine‐Q, and (±)‐lycoflexine, were completed in a highly stereoselective manner. The Pauson–Khand reaction of 4‐methylidene‐6‐siloxyoct‐1‐en‐7‐yne followed by regio‐ and stereoselective hydrogenation led to the short‐step preparation of the bicyclo[4.3.0]nonenone intermediate bearing a methyl group with the required stereochemistry. The subsequent chemical manipulation of the bicyclic compound afforded the 6‐5‐9‐membered tricyclic dioxo compound, which was then transformed into the four targeted alkaloids in an alternative and more efficient fashion.
Three‐Dimensional Architectures Incorporating Stereoregular Donor–Acceptor Stacks
Authors: Cao Dennis , Juríček Michal , Brown Zachary J. , Sue Andrew C.‐H. , Liu Zhichang , Lei Juying , Blackburn Anthea K. , Grunder Sergio , Sarjeant Amy A. , Coskun Ali , Wang Cheng , Farha Omar K. , Hupp Joseph T. , Stoddart J. Fraser 
Published: May 2013

AbstractWe report the synthesis of two [2]catenane‐containing struts that are composed of a tetracationic cyclophane (TC4+) encircling a 1,5‐dioxynaphthalene (DNP)‐based crown ether, which bears two terphenylene arms. The TC4+ rings comprise either 1) two bipyridinium (BIPY2+) units or 2) a BIPY2+ and a diazapyrenium (DAP2+) unit. These degenerate and nondegenerate catenanes were reacted in the presence of Cu(NO3)2⋅2.5 H2O to yield Cu‐paddlewheel‐based MOF‐1050 and MOF‐1051. The solid‐state structures of these MOFs reveal that the metal clusters serve to join the heptaphenylene struts into grid‐like 2D networks. These 2D sheets are then held together by infinite donor–acceptor stacks involving the [2]catenanes to produce interpenetrated 3D architectures. As a consequence of the planar chirality associated with both the DNP and hydroquinone (HQ) units present in the crown ether, each catenane can exist as four stereoisomers. In the case of the nondegenerate (bistable) catenane, the situation is further complicated by the presence of translational isomers. Upon crystallization, however, only two of the four possible stereoisomers—namely, the enantiomeric RR and SS forms—are observed in the crystals. An additional element of co‐conformational selectivity is present in MOF‐1051 as a consequence of the substitution of one of the BIPY2+ units by a DAP2+ unit: only the translational isomer in which the DAP2+ unit is encircled by the crown ether is observed. The overall topologies of MOF‐1050 and MOF‐1051, and the selective formation of stereoisomers and translational isomers during the kinetically driven crystallization, provide evidence that weak noncovalent bonding interactions play a significant role in the assembly of these extended (super)structures.
Highly Efficient Fine Dust Deposition from Small‐Scale Heating Systems with a Baghouse Filter
Authors: Schiller Sascha , Schmidt Hans‐Joachim 
Published: May 2013

AbstractZur Erfüllung der Anforderungen der novellierten ersten Bundesimmissionsschutzverordnung (1. BImSchV: Verordnung über kleine und mittlere Feuerungsanlagen) wurde ein Schlauchfiltersystem für den Gebrauch in kleinen und mittleren Feuerungsanlagen entwickelt. Ein zur Filtration benötigtes Filterhilfsmittel wird vollautomatisch portioniert, dispergiert und dem Prozess zugeführt. Mit dieser Technik ist es möglich, den Feinstaubgehalt im Abgas auf unter 1 mg m–3 i.N. zu senken und damit die geforderten Grenzwerte weit zu unterschreiten.
Optical Multimode Online Probe: Detection and Analysis of Particle Collectives
Authors: Mickler Matthias , Bart Hans‐Jörg 
Published: May 2013

AbstractDie vorgestellte Optical Multimode Online Probe verwendet telezentrische Beleuchtung mittels Hochleistungs‐Mikro‐LED (493 lm) und ein objektseitig‐telezentrisches Objektiv zur Online‐Analyse von Tropfenkollektiven. Es entstehen relative Messfehler von < 2 – 5 % (Durchlicht) bzw. <60; 12 % (Auflicht) bezogen auf die Partikeldurchmesser. Aufbauend auf der Distanztransformation zur Analyse der Durchlichtabbildungen wird ein adaptiver Vorsegmentierungsansatz auf Basis des Random Forest Classifiers vorgestellt. Die Abweichungen bezogen auf die Pixelzahl liegen bei 1 bis 6 %, nach Auswertung der Kreise bei 12,9 % bezogen auf den mittleren Partikeldurchmesser.
Current Developments in Cellulase Engineering
Authors: Rentmeister Andrea 
Published: May 2013

AbstractDie Hydrolyse von Cellulose aus nachwachsenden Rohstoffen, die nicht als Nahrungsmittel dienen, stellt einen Schlüsselschritt für die effiziente Gewinnung von Biokraftstoffen wie Ethanol oder Butanol dar. Die Verbesserung von Cellulasen könnte den Gesamtprozess kosteneffizienter machen und wird mittels verschiedener Strategien verfolgt. Neue Zusammenstellungen von Cellulasen zielen langfristig darauf ab, eine Gesamtbioprozessierung zu erreichen. Hierfür wurden Designer‐Cellulosomen konstruiert und gut fermentierende Organismen mit Cellulaseaktivität versehen. Außerdem werden Cellulasen mit verbesserter Thermostabilität und Aktivität benötigt. Aktuelle Entwicklungen im Bereich Cellulase‐Engineering werden zusammengefasst und die Erfolge und Limitierungen herausgestellt.
Mild Therapeutic Hypothermia After Out‐Of‐Hospital Cardiac Arrest Complicating ST‐Elevation Myocardial Infarction: Long‐term Results in Clinical Practice
Authors: Zimmermann Stefan , Flachskampf Frank A. , Schneider Reinhard , Dechant Katharina , Alff Anna , Klinghammer Lutz , Rittger Harald , Achenbach Stephan 
Published: May 2013

AbstractBackgroundRecently, mild therapeutic hypothermia (MTH) has been integrated into the European resuscitation guidelines to improve outcomes after out‐of‐hospital cardiac arrest (OHCA). Data on long‐term results are limited, especially in patients with acute ST‐elevation myocardial infarction (STEMI).HypothesisInvasive MTH influences long‐term prognosis after OHCA due to STEMI.MethodsWe analyzed 48 patients who underwent emergency coronary angiography for STEMI after witnessed OHCA. In 24 consecutive patients, MTH was performed via intravascular cooling (CoolGard System, 34°C maintained for 24 hours) after initialization by rapid infusion of cold saline. Clinical, procedural, and mortality data were compared to 24 historical controls. Neurological recovery was assessed using the Cerebral Performance Category score (CPC) at 30‐day and 1‐year follow‐up.ResultsMedian time delay until arrival of emergency medical service was 6 minutes (MTH group) vs 6.5 minutes (controls) (P = 0.16). Initial rhythm was ventricular fibrillation in 75% vs 66.7% (P = 0.75). There were no differences regarding baseline characteristics, angiographic findings, and success of cardiac catheterization procedures. MTH was not associated with a higher frequency of bleeding complications or of pneumonia. Thirty‐day mortality was 33.3% in both groups. One‐year mortality was 37.5% (MTH group) vs 50% (controls) (P = 0.56). At 1 year, favorable neurological outcome (CPC ≤2) was significantly more frequent in the MTH group (58.3% vs 20.8%, P = 0.017). Multivariate analysis identified MTH as independent predictor of favorable neurological outcome (P < 0.02, odds ratio: 12.73).ConclusionsMTH via intravascular cooling improves neurological long‐term prognosis after OHCA due to STEMI and is safe in clinical practice.
Homogeneous Solutions of Fully Nonlinear Elliptic Equations in Four Dimensions
Authors: Nadirashvili Nikolai , Vlăduţ Serge 
Published: May 2013

AbstractWe prove that there is no nontrivial homogeneous order 2 analytic outside zero solutions of fully nonlinear, uniformly elliptic equations in ℝ. © 2013 Wiley Periodicals, Inc.
New Deposition Technique for Metal Films Containing Inorganic Fullerene‐Like (IF) Nanoparticles
Authors: Goldbart Ohad , Yoffe Alexander , Cohen Sidney R. , Rosentsveig Rita , Feldman Yishay , Rapoport Lev , Tenne Reshef 
Published: May 2013

AbstractThis study describes a new method for fabrication of thin composite films using physical vapor deposition (PVD). Titanium (Ti) and hybrid films of titanium containing tungsten disulphide nanoparticles with inorganic fullerene‐like structure (Ti/IF‐WS2) were fabricated with a modified PVD machine. The evaporation process includes the pulsed deposition of IF‐WS2 by a sprayer head. This process results in IF‐WS2 nanoparticles embedded in a Ti matrix. The layers were characterized by various techniques, which confirm the composition and structure of the hybrid film. The Ti/IF‐WS2 shows better wear resistance and a lower friction coefficient when compared to the Ti layer or Ti substrate. The Ti/IF films show very good antireflective properties in the visible and near‐IR region. Such films may find numerous applications, for example, in the aerospace and medical technology.
Protein Resistance of Surfaces Modified with Oligo(Ethylene Glycol) Aryl Diazonium Derivatives
Authors: Fairman Callie , Ginges Joshua Z. , Lowe Stuart B. , Gooding J. Justin 
Published: May 2013

AbstractAnti‐fouling surfaces are of great importance for reducing background interference in biosensor signals. Oligo(ethylene glycol) (OEG) moieties are commonly used to confer protein resistance on gold, silicon and carbon surfaces. Herein, we report the modification of surfaces using electrochemical deposition of OEG aryl diazonium salts. Using electrochemical and contact angle measurements, the ligand packing density is found to be loose, which supports the findings of the fluorescent protein labelling that aryl diazonium OEGs confer resistance to nonspecific adsorption of proteins albeit lower than alkane thiol‐terminated OEGs. In addition to protein resistance, aryl diazonium attachment chemistry results in stable modification. In common with OEG species on gold electrodes, OEGs with distal hydroxyl moieties do confer superior protein resistance to those with a distal methoxy group. This is especially the case for longer derivatives where superior coiling of the OEG chains is possible.
Viscosity Mixing Rules for Binary Systems Containing One Ionic Liquid
Authors: Tariq Mohammed , Altamash Tausif , Salavera Daniel , Coronas Alberto , Rebelo Luis P. N. , Lopes Jose N. Canongia 
Published: May 2013

AbstractIn this work the applicability of four of the most commonly used viscosity mixing rules to [ionic liquid (IL)+molecular solvent (MS)] systems is assessed. More than one hundred (IL+MS) binary mixtures were selected from the literature to test the viscosity mixing rules proposed by 1) Hind (Hi), 2) Grunberg and Nissan (G–N), 3) Herric (He) and 4) Katti and Chaudhri (K–C). The analyses were performed by estimating the average (absolute or relative) deviations, AADs and ARDs, between the available experimental data and the predicted ideal mixture viscosity values obtained by means of each rule. The interaction terms corresponding to the adjustable parameters inherent to each rule were also calculated and their trends discussed.