bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Design of the Lurgi Reactor for Methanol Synthesis Industry
Authors: Walid Belabbas Abou Bakr Tariq , Hassiba Benyounes , Boumediene Haddou , Weifeng Shen 
Published: August 2018

AbstractCurrent studies are devoted to promote the production yield of the methanol synthesis process for treating large feed capacities in Algerian methanol manufacture industry by designing new reactor technologies. In order to achieve a high yield of methanol, the performance of methanol synthesis is improved by substituting the quench reactor by a new Lurgi reactor. The design of operating parameters of the Lurgi reactor involves the effect of CO2 injection on methanol production yield and the catalyst deactivation. The simulation results demonstrate that under the same industrial operating conditions the conversion rate of reactants increases from 23 % in the quench reactor to 37 % in the Lurgi reactor and the methanol yield can be increased by 33 % when substituting the quench reactor by the Lurgi reactor
Charge‐Transfer Salts of 6,6‐Dicyanopentafulvenes: From Topology to Charge Separation in Solution
Authors: Finke Aaron D. , Zalibera Michal , Confortin Daria , Kelterer Anne‐Marie , Mensing Christian , Haberland Sophie , Diederich François , Gescheidt Georg 
Published: August 2018

Abstract6,6‐Dicyanopentafulvene derivatives and metallocenes with redox potentials appropriate for forming their radical anions form highly persistent donor–acceptor salts. The charge‐transfer salts of 2,3,4,5‐tetraphenyl‐6,6‐dicyanofulvene with cobaltocene (1⋅Cp2Co) and 2,3,4,5‐tetrakis(triisopropylsilyl)‐6,6‐dicyanofulvene with decamethylferrocene (2⋅Fc*) have been prepared. The X‐ray structures of the two salts, formed as black plates, were obtained and are discussed herein. Compared with neutral dicyanopentafulvenes, the chromophores in the metallocene salts show substantial changes in bond lengths and torsional angles in the solid state. EPR, NMR, and optical spectroscopy, as well as superconducting quantum interference device (SQUID) measurements, reveal that charge‐separation in the crystalline states and in frozen and fluid solutions depends on subtle differences of redox potentials, geometry, and on ion pairing. Whereas 1⋅Cp2Co reveals paramagnetic character in the crystalline state and in solution, compound 2⋅Fc* shows a delicate balance between para‐ and diamagnetism, depending on the temperature and solvent characteristics.
Ionic Donor–Acceptor Chain Derived from an Electron‐Transfer Reaction of a Paddlewheel‐Type Diruthenium(II, II) Complex and N,N′‐Dicyanoquinonediimine
Authors: Sekine Yoshihiro , Shimada Tomoka , Miyasaka Hitoshi 
Published: August 2018

AbstractA new ionic donor–acceptor (D+A−) chain compound, [{Ru2(2,6‐(CF3)2PhCO2)2(p‐PhPhCO2)2}DMDCNQI] (1; 2,6‐(CF3)2PhCO2−=2,6‐bis(trifluoromethyl)benzoate; p‐PhPhCO2−=4‐biphenylcarboxylate; DMDCNQI=2,5‐dimethyl‐N,N′‐dicyanoquinonediimine) was isolated and structurally characterized. It represents the first of this type of ionic chain compounds.
Two Pairs of Chiral “Tower‐Like” Ln4Cr4 (Ln=Gd, Dy) Clusters: Syntheses, Structure, and Magnetocaloric Effect
Authors: Cui Chenhui , Cao Jia‐Peng , Luo Xi‐Ming , Lin Qing‐Fang , Xu Yan 
Published: August 2018

AbstractTwo pairs of novel chiral chromium lanthanide compounds, formulated as l‐ and d‐[Gd4Cr4(IN)10(μ3‐OH)4(μ4‐O)4(H2O)12]⋅[IN]2⋅8 H2O (1 and 3), and l‐ and d‐[Dy4Cr4(IN)11(μ3‐OH)4(μ4‐O)4(H2O)8]⋅[IN]⋅1.5 H2O (2 and 4) (HIN=isonicotinic acid) have been successfully synthesized and characterized. Structural analysis reveals that four Ln3+ ions and four Cr3+ ions connect with each other and yield a “tower‐like” [Ln4Cr4] skeleton. Apart from the above featuring an aesthetically charming structure, circular dichroism (CD) spectra confirm that compounds 1 and 3, 2 and 4 are enantiomers. To the best of our knowledge, these are the largest chiral chromium lanthanide compounds. In addition, magnetic interaction shows that Gd (the mixture of 1 and 3) exhibits significant cryogenic magnetocaloric effect (MCE) with −ΔSm=18.08 J kg−1 K−1(34.69 mJ cm−3 K−1). Also, the observed second‐harmonic generation efficiencies of [Gd4Cr4(IN)10(μ3‐OH)4(μ4‐O)4(H2O)12]⋅[IN]2⋅8 H2O and [Dy4Cr4(IN)11(μ3‐OH)4(μ4‐O)4(H2O)8]⋅[IN]⋅1.5 H2O are 0.3 and 0.4 times that of urea, respectively.
Yellow Emission from Low Coordination Site of Sr2SiO4:Eu2+, Ce3+: Influence of Lanthanide Dopants on the Electron Density and Crystallinity in Crystal Site Engineering Approach
Authors: Mani Rajaboopathi , Gupta Santosh Kumar , Ghosh Partha Sarathi , Jiang Huaidong 
Published: August 2018

AbstractLanthanide doping through a crystal site engineering approach tunes the emission wavelength suitable for LED applications, but weak emission from low coordination sites remains a huge challenge. Herein the use of a sensitizer is reported to enhance the emission strength and unravel the crystallinity and phase, as this approach demands a large amount of dopants. Doping of Eu2+ ions at SrO10 and SrO9 sites of Sr2SiO4 (S2S), respectively, tunes the emission from green to yellow and controlled doping of a Ce3+ sensitizer quadruples the quantum efficiency of yellow emission. Remarkably, doping of Eu2+ at the SrO9 site produces polycrystals, whereas co‐doping of Ce3+ and Eu2+ at the same site produces single crystals. DFT calculations further delineate the underlying changes wherein strong interaction of dopant with its neighbours determines the electron density, and thus the crystallinity and phase, rather than usual explanation of aliovalent conditions, which is further substantiated by TEM results. Irrespective of dopant valence, use of large amounts of dopants and their interaction with the host is responsible for the crystallinity and phase change (α′‐S2S to β‐S2S). The XPS valence band spectra experimentally evidences the changes in bonding nature of O 2p and O 2s orbitals of silicate and its electron density, due to doping at the two sites. In short, the outcomes resulting from this work could be extended for the development of other two‐coordination site lanthanide‐doped materials and crystallization of inorganic materials.
Mapping the Magnetic Anisotropy at the Atomic Scale in Dysprosium Single‐Molecule Magnets
Authors: Klahn Emil A. , Gao Chen , Gillon Beatrice , Gukasov Arsen , Fabrèges Xavier , Piltz Ross O. , Jiang Shang‐Da , Overgaard Jacob 
Published: August 2018

AbstractThe anisotropy of the magnetic properties of molecular magnets is a key descriptor in the search for improved magnets. Herein, it is shown how an analytical approach using single‐crystal polarized neutron diffraction (PND) provides direct access to atomic magnetic susceptibility tensors. The technique was applied for the first time to two Dy‐based single‐molecule magnets and showed clear axial atomic susceptibility for both DyIII ions. For the triclinic system, bulk magnetization methods are not symmetry‐restricted, and the experimental magnetic easy axes from both PND, angular‐resolved magnetometry (ARM), and theoretical approaches all match reasonably well. ARM curves simulated from the molecular susceptibility tensor determined with PND show strong resemblance with the experimental ones. For the monoclinic compound, comparison can only be made with the theoretically calculated magnetic anisotropy, and in this case PND yields an easy‐axis direction that matches that predicted by electrostatic methods. Importantly, this technique allows the determination of all elements of the magnetic susceptibility tensor and not just the easy‐axis direction, as is available from electrostatic predictions. Furthermore, it has the capacity to provide each of the anisotropic magnetic susceptibility tensors for all independent magnetic ions in a molecule and thus allows studies on polynuclear complexes and compounds of higher crystalline symmetry than triclinic.
Borabicyclo[3.2.0]heptadiene: A Fused Bicyclic Isomer of Borepin
Authors: Kelch Hauke , Kachel Stephanie , Wahler Johannes , Celik Mehmet Ali , Stoy Andreas , Krummenacher Ivo , Kramer Thomas , Radacki Krzysztof , Braunschweig Holger 
Published: August 2018

AbstractA new isomer of borepin, identified as 2‐borabicyclo[3.2.0]hepta‐3,6‐diene by single‐crystal X‐ray diffraction and heteronuclear NMR spectroscopy, was obtained by reaction of 1‐mesityl‐2,3,4,5‐tetraphenylborole with the diaminoalkyne bis(piperidyl)acetylene. Analogous reactions of the alkyne with other borole derivatives generated seven‐membered borepins, in which a second equivalent of the alkyne was found to insert into the exocyclic B−C bond. Results of mechanistic DFT studies as well as differences in the reactivity of the boroles toward the diaminoalkyne are discussed.
X‐ray Constrained Spin‐Coupled Wavefunction: a New Tool to Extract Chemical Information from X‐ray Diffraction Data
Authors: Genoni Alessandro , Franchini Davide , Pieraccini Stefano , Sironi Maurizio 
Published: August 2018

AbstractThe X‐ray constrained wavefunction (XCW) approach is a reliable and widely used method of quantum crystallography that allows the determination of wavefunctions compatible with X‐ray diffraction data. So far, all the existing XCW techniques have been developed in the framework of molecular orbital theory and, consequently, provide only pictures of the “experimental” electronic structures that are far from the traditional chemical perception. Here a new strategy is proposed that, by combining the XCW philosophy with the spin‐coupled method of valence bond theory, enables direct extraction of traditional chemical information (e.g., weights of resonance structures) from X‐ray diffraction measurements. Preliminary results have shown that the new technique is really able to efficiently capture the effects of the crystal environment on the electronic structure, and can be considered as a new useful tool to perform chemically sound analyses of the X‐ray diffraction data.
CFD simulation of annular oil flow wrapped with water
Authors: Siqueira Fabio C. S. , Farias Irene S. , Moraes Júnior Deovaldo , dos S. Vianna Ardson 
Published: August 2018

AbstractThe transport of heavy oil in tubes is energy intensive since the oil viscosity can reach values of 10 500 000 cP. This study focuses on the transport of oil in a piping system by an annular flow of oil wrapped with water, since this alternative reduces head loss. The piping system was comprised of horizontal tubes, curves, and vertical tubes. The assumptions for the CFD simulation were the following: 3D geometry, turbulent flow, and isothermal system as well as incompressible, steady‐state, and transient flow. A mesh convergence study was carried out. The residue for pressure and velocity dropped at least three orders of magnitude. The inter‐phase‐slip Algorithm (IPSA), algebraic slip model (ASLP), scalar equation method (SEM), and Phoenics models were applied to calculate the interaction between the phases. Turbulence was modelled with default k‐ϵ and k‐ω models and the LES strategy by using a Smagorinsky sub‐grid scale model. The density profiles generated in the CFD simulation were compared with experimental data and a resemblance was observed. The transient simulation showed a swirling flow that was experimentally observed, which was a result of synergy of multiphase flow, horizontal tube, curve, and vertical tube.
Molecular Recognition of a Thomsen–Friedenreich Antigen Mimetic Targeting Human Galectin‐3
Authors: Santarsia Sabrina , Grosso Ana Sofia , Trovão Filipa , Jiménez‐Barbero Jesús , Carvalho Ana Luísa , Nativi Cristina , Marcelo Filipa 
Published: August 2018

AbstractOverexpression of the Thomsen–Friedenreich (TF) antigen in cell membrane proteins occurs in 90 % of adenocarcinomas. Additionally, the binding of the TF antigen to human galectin‐3 (Gal‐3), also frequently overexpressed in malignancy, promotes cancer progression and metastasis. In this context, structures that interfere with this specific interaction have the potential to prevent cancer metastasis. A multidisciplinary approach combining the optimized synthesis of a TF antigen mimetic with NMR, X‐ray crystallography methods, and isothermal titration calorimetry assays was used to unravel the molecular structural details that govern the Gal‐3/TF mimetic interaction. The TF mimetic has a binding affinity for Gal‐3 similar to that of the TF natural antigen and retains the binding epitope and bioactive conformation observed for the native antigen. Furthermore, from a thermodynamic perspective, a decrease in the enthalpic contribution was observed for the Gal‐3/TF mimetic complex; however, this behavior is compensated by a favorable gain in entropy. From a structural perspective, these results establish our TF mimetic as a scaffold to design multivalent solutions to potentially interfere with Gal‐3 aberrant interactions and for likely use in hampering Gal‐3‐mediated cancer cell adhesion and metastasis.
An area‐efficient low‐power SCM topology for high performance network‐on Chip (NoC) architecture using an optimized routing design
Authors: Poovendran R. , Sumathi S. 
Published: August 2018

SummaryThe incorporation of network‐on‐Chip with communication delivers a strengthening solution to the rising complexity and problems in system‐on‐chip. Here, mesh topology is shortly connected, utilizing the symmetric properties of the network, and is introduced. In addition, 4x4‐Router Architecture–Carry Select Adder (4x4‐RA‐CSLA) method is proposed to improve the function of the Router Architecture (RA) in the network. These features make the system achieve efficient architecture in terms of lower area and power for the interconnection of network scenarios. This new architecture is debugged using ModelSim with Verilog code. The experimental result shows improvement in area and power.
Safety Threshold Considerations for Sunscreen Systemic Exposure: A Simulation Study
Authors: Wang Jian , Ganley Charles J. 
Published: August 2018

Sunscreens are regulated as over‐the‐counter drugs in the United States. Some sunscreen ingredients are absorbed into the systemic circulation, which raises concerns about the safety of these drugs. There is limited information on the systemic exposure for most sunscreen ingredients. This report estimates the systemic absorption of two sunscreen active ingredients, oxybenzone and enzacamene, by developing a pharmacokinetic model from published sunscreen absorption data and compares the results with safety thresholds proposed by the US Food and Drug Administration and in the literature. Our analysis indicates that systemic absorption can be substantial, and evaluation of the systemic exposure of sunscreen ingredients is warranted to better assess any long‐term risks of use.
Free‐Sustaining Three‐Dimensional S235 Steel‐Based Porous Electrocatalyst for Highly Efficient and Durable Oxygen Evolution
Authors: Han Weijia , Kuepper Karsten , Hou Peilong , Akram Wajiha , Eickmeier Henning , Hardege Jörg , Steinhart Martin , Schäfer Helmut 
Published: August 2018

AbstractA novel oxygen evolution reaction (OER) catalyst (3 D S235‐P steel) based on a steel S235 substrate was successfully prepared by facile one‐step surface modification. The standard carbon‐manganese steel was phosphorized superficially, which led to the formation of a unique 3 D interconnected nanoporous surface with a high specific area that facilitated the electrocatalytically initiated oxygen evolution reaction. The prepared 3 D S235‐P steel exhibited enhanced electrocatalytic OER activities in the alkaline regime, as confirmed by a low overpotential (326 mV at a 10 mA cm−2) and a small Tafel slope of 68.7 mV dec−1. Moreover, the catalyst was found to be stable under long‐term usage conditions, functioning as an oxygen‐evolving electrode at pH 13, as evidenced by the sufficient charge‐to‐oxygen conversion rate (faradaic efficiency: 82.11 and 88.34 % at 10 and 5 mA cm−2, respectively). In addition, it turned out that the chosen surface modification delivered steel S235 as an OER electrocatalyst that was stable under neutral pH conditions. Our investigation revealed that the high catalytic activities likely stemmed from the generated Fe/(Mn) hydroxide/oxohydroxides generated during the OER process. Phosphorization treatment therefore not only is an efficient way to optimize the electrocatalytic performance of standard carbon‐manganese steel but also enables for the development of low‐costing and abundant steels in the field of energy conversion.
Pompeji des Perms
Authors: Rößler Ronny , Luthardt Ludwig , Zierold Thorid 
Published: August 2018

AbstractDer „Versteinerte Wald von Chemnitz“ ist eine etwa 291 Millionen Jahre alte paläobotanische Fossillagerstätte – und ein außergewöhnlich gut vulkanisch konserviertes Ökosystem. Geologen gewinnen hier Einblicke in das Werden und Vergehen von Lebensräumen und die Dynamiken von Umwelt‐ und Klimawandel.
Petrogenesis and metallogenic implications of Cretaceous magmatism in Central Lhasa, Tibetan Plateau: A case study from the Lunggar Fe skarn deposit and perspective review
Authors: Cao Hua‐Wen , Zhang Yun‐Hui , Santosh M. , Li Guang‐Ming , Hollis Steven P. , Zhang Lin‐Kui , Pei Qiu‐Ming , Tang Li , Duan Zhi‐Ming 
Published: August 2018

The Lhasa terrane is one of the major segments of the Tibetan Plateau, with widespread Mesozoic to Cenozoic magmatic and metallogenic records. Here, we investigate timing and characteristics of magmatism associated with the Lunggar Fe skarn deposit in Central Lhasa. We also present Sr–Nd–Pb and Hf (zircon) isotopic data on three associated intrusions to gain insights on the tectonic and metallogenic evolution of the region. Our data reveal at least two magmatic pulses in Lunggar represented by Early Cretaceous I‐type granodiorite (112.9 ± 1.5 Ma) and granite porphyry (112.6 ± 1.3 Ma) with magma generation related to slab break‐off associated with the Bangong–Nujiang Ocean during closure of the Meso‐Tethyan ocean at ~113 Ma. Iron skarn mineralization at Lunggar was contemporaneous with local Early Cretaceous intrusive activity. Following this, Late Cretaceous adakitic diorite (90.5 ± 1.5 Ma) formed from delaminated thickened crust at ~91 Ma related to the northern subduction of the Yarlung‐Zangbo oceanic plate. We also provide a comprehensive review of the Cretaceous tectonic evolution of Central Lhasa, which trace the tectonic evolution as follows: (a) 145–120 Ma: southward subduction of the Bangong–Nujiang oceanic plate under the Lhasa terrane; (b) 120–115 Ma: Lhasa‐Qiangtang continental collision; (c) 115–110 Ma: slab break‐off of the Bangong–Nujiang Ocean; (d) 110–95 Ma: crustal thickening of the Central Lhasa lower crust; (e) 95–80 Ma: delamination of lithospheric mantle; and (f) 80–65 Ma: northward subduction of the Yarlung‐Zangbo oceanic plate and subsequent slab rollback. The related metallogenic events in Central Lhasa include (a) ~115–110 Ma skarn Fe mineralization associated with slab break‐off; (b) ~90–80 Ma porphyry Cu–Au mineralization formed in delaminated thickened crust of Central Lhasa; and (c) ~65 Ma skarn Pb–Zn mineralization produced from slab rollback of the Yarlung‐Zangbo Ocean.
Brainstem network disruption: A pathway to sudden unexplained death in epilepsy?
Authors: Mueller Susanne G. , Nei Maromi , Bateman Lisa M. , Knowlton Robert , Laxer Kenneth D. , Friedman Daniel , Devinsky Orrin , Goldman Alica M. 
Published: August 2018

AbstractObservations in witnessed Sudden Unexpected Death in Epilepsy (SUDEP) suggest that a fatal breakdown of the central autonomic control could play a major role in SUDEP. A previous MR study found volume losses in the mesencephalon in focal epilepsy that were more severe and extended into the lower brainstem in two patients who later died of SUDEP. The aims of this study were to demonstrate an association (1) between brainstem volume loss and impaired autonomic control (reduced heart rate variability [HRV]); (2) between brainstem damage and time to SUDEP in patients who later died of SUDEP. Two populations were studied: (1) Autonomic system function population (ASF, 18 patients with focal epilepsy, 11 controls) with HRV measurements and standardized 3 T MR exams. (2) SUDEP population (26 SUDEP epilepsy patients) with clinical MRI 1–10 years before SUDEP. Deformation‐based morphometry of the brainstem was used to generate profile similarity maps from the resulting Jacobian determinant maps that were further characterized by graph analysis to identify regions with excessive expansion indicating significant volume loss or atrophy. The total number of regions with excessive expansion in ASF was negatively correlated with HRV (r = −.37, p = .03), excessive volume loss in periaqueductal gray/medulla oblongata autonomic nuclei explained most of the HRV associated variation (r/r2 = −.82/.67, p < .001). The total number of regions with excessive expansion in SUDEP was negatively correlated with time to SUDEP (r = −.39, p = .03), excessive volume loss in the raphe/medulla oblongata at the obex level explained most of the variation of the time between MRI to SUDEP (r/r2 = −.60/.35,p = .001). Epilepsy is associated with brainstem atrophy that impairs autonomic control and can increase the risk for SUDEP if it expands into the mesencephalon.
Pillar[5]arene‐stabilized Plasmonic Nanoparticles as Selective SERS Sensors
Authors: Montes‐García Verónica , Rodal‐Cedeira Sergio , Cordero‐Ferradás María José , Gómez Borja , García‐Río Luis , Pastoriza‐Santos Isabel , Pérez‐Juste Jorge 
Published: August 2018

AbstractWe present here a simple procedure for the surface modification of plasmonic nanoparticles (NPs) with a cationic water‐soluble ammonium pillar[5]arene (AP[5]A) in order to create selective surface‐enhanced Raman scattering (SERS) spectroscopy based sensors. The strategy is based on a ligand exchange reaction between the AP[5]A and the stabilizing agent of the as‐prepared plasmonic NPs. The approach could be applied to plasmonic nanoparticles either negatively charged, stabilized by citrate ions (Au spheres) or positively charged, stabilized by cetyltrimethylammonium bromide (Au and Au@Ag nanorods). The SERS performance of all systems was studied as a function of NP size and excitation laser line by using an analyte with no affinity towards the metal surface such as pyrene. The analytical enhancement factor (AEF) for the different systems was estimated between 0.55×104 and 1.49×105. Finally the synergistic effect of combining supramolecular chemistry and plasmonic NPs is demonstrated through SERS‐based detection, in aqueous media, of molecules with no affinity towards a bare plasmonic substrate such as the contaminant pyrene or the biomolecule pyocyanin with nanomolar limit of detection.
Currency risk premia: Perceptions of downside risk and deviations from benchmark values
Authors: Furnagiev Steven , Stillwagon Joshua 
Published: August 2018

AbstractThis paper examines the empirical performance of an alternative model of the currency risk premium. This model relates risk not to the variance of returns but rather to potential crash risk based on the deviation, or “gap,” between the exchange rate and perceptions of its benchmark value. The model is tested using a novel data set of traders' exchange rate forecasts, from 1986:08 to 2013:09. The forecast data eliminate the need for a joint hypothesis about expectations formation through direct measurement of the market's ex ante premium. To measure the benchmark value, rather than use purchasing power parity, we relate it to recent levels through a moving average. Strong support is found for the prediction that the premium comoves positively with the “gap” measure of risk, according to cointegrated vector autoregression analyses for all four markets examined. This result is robust for moving averages from six to 24 months and when controlling for exchange rate volatility. The findings suggesthowinvestors assess downside risk ex ante, at least in part, and may rationalize the application of certain technical analysis.