bluuebunny/crossref_metadata_2025_split huggingface dataset:
Size‐Dependent Water Structures in Carbon Nanotubes
Authors: Ohba Tomonori 
Published: June 2014

AbstractWater surrounded by hydrophobic interfaces affects a variety of chemical reactions and biological activities. Carbon nanotubes (CNTs) can be used to investigate the behavior of water at hydrophobic interfaces. Here, we determined the fundamental unit of water by evaluating the ice‐like cluster formation of water in the limited hydrophobic nanospaces of CNTs, using X‐ray diffraction and molecular simulation analysis. The water in CNTs with a diameter of 1 nm had fewer hydrogen bonds than bulk water under ambient conditions. In CNTs with diameters of 2 and 3 nm, water formed nanoclusters even under ambient conditions, because of prolific hydrogen bonding; predominant ice‐like cluster formation was induced in the 2–3 nm nanospaces. The results confirming the cluster formation in the CNTs also demonstrated that the critical cluster size was 0.8–3.4 nm. The fundamental cluster size was 0.8 nm; these results indicated that 0.8 nm clusters are the fundamental units of water assemblies.
18π‐Electron Tautomeric Benziphthalocyanine: A Functional Near‐Infrared Dye with Tunable Aromaticity
Authors: Toriumi Naoyuki , Muranaka Atsuya , Hirano Keiichi , Yoshida Kengo , Hashizume Daisuke , Uchiyama Masanobu 
Published: June 2014

AbstractDihydroxybenziphthalocyanine 1, with bulky aryloxy groups, has been synthesized and characterized by X‐ray crystallography, NMR and UV/Vis‐NIR spectroscopy, and theoretical calculations. Macrocycle 1 is the first example of an aromatic benziphthalocyanine with an 18π‐electron structure, and was found to exist as an equilibrium mixture of weakly aromatic and strongly aromatic tautomers. The aromaticity and near‐IR absorption can be controlled by chemical modification at the reactive resorcinol moiety and by variation of the solvent.
Rapid Selective Electrocatalytic Reduction of Carbon Dioxide to Formate by an Iridium Pincer Catalyst Immobilized on Carbon Nanotube Electrodes
Authors: Kang Peng , Zhang Sheng , Meyer Thomas J. , Brookhart Maurice 
Published: June 2014

AbstractAn iridium pincer dihydride catalyst was immobilized on carbon nanotube‐coated gas diffusion electrodes (GDEs) by using a non‐covalent binding strategy. The as‐prepared GDEs are efficient, selective, durable, gas permeable electrodes for electrocatalytic reduction of CO2 to formate. High turnover numbers (ca. 54 000) and turnover frequencies (ca. 15 s−1) were enabled by the novel electrode architecture in aqueous solutions saturated in CO2 with added HCO3−.
Unprecedented Strong Lewis Bases—Synthesis and Methyl Cation Affinities of Dimethylamino‐Substituted Terpyridines
Authors: Hommes Paul , Fischer Christina , Lindner Christoph , Zipse Hendrik , Reissig Hans‐Ulrich 
Published: June 2014

AbstractA versatile method for the synthesis of functionalized 2,2′:6′,2′′‐terpyridines by assembly of the terminal pyridine rings is presented. The cyclization precursors—bis‐β‐ketoenamides—are prepared from 4‐substituted 2,6‐pyridinedicarboxylic acids and acetylacetone or its corresponding enamino ketone. Treatment with trimethylsilyl trifluoromethanesulfonate induces a twofold intramolecular condensation providing an efficient access to 4,4′′‐di‐ and 4,4′,4′′‐trifunctionalized 6,6′′‐dimethyl‐2,2′:6′,2′′‐terpyridines. Using this method, hitherto unknown 4,4′′‐bis(dimethylamino)‐ and 4,4′,4′′‐tris(dimethylamino)terpyridines have been prepared that show remarkably high calculated Lewis basicities.
Optical Control of Acetylcholinesterase with a Tacrine Switch
Authors: Broichhagen Johannes , Jurastow Innokentij , Iwan Katharina , Kummer Wolfgang , Trauner Dirk 
Published: June 2014

AbstractPhotochromic ligands have been used to control a variety of biological functions, especially in neural systems. Recently, much effort has been invested in the photocontrol of ion channels and G‐protein coupled receptors found in the synapse. Herein, we describe the expansion of our photopharmacological approach toward the remote control of an enzyme. Building on hallmark studies dating from the late 1960s, we evaluated photochromic inhibitors of one of the most important enzymes in synaptic transmission, acetylcholinesterase (AChE). Using structure‐based design, we synthesized several azobenzene analogues of the well‐known AChE inhibitor tacrine (THA) and determined their effects on enzymatic activity. One of our compounds, AzoTHA, is a reversible photochromic blocker of AChE in vitro and ex vivo with high affinity and fast kinetics. As such, AzoTHA can be used to control synaptic transmission on the neuromuscular endplate based on the light‐dependent clearance of a neurotransmitter.
Conformationally Constrained Cyclic Peptides: Powerful Scaffolds for Asymmetric Catalysis
Authors: Zheng Lifei , Marcozzi Alessio , Gerasimov Jennifer Y. , Herrmann Andreas 
Published: June 2014

AbstractCyclic peptides containing a disulfide bridge were identified as a simple and versatile coordination sphere for asymmetric catalysis. Upon complexation with Cu2+ ions they catalyze Diels–Alder and Friedel–Crafts reactions with high enantioselectivities of up to 99 % ee and 86 % ee, respectively. Moreover, the peptides ligands were systematically optimized with the assistance of “Alanine Scanning”. This biomolecular design could greatly expand the choice of peptide scaffolds for artificial metallopeptide catalysts.
Formal (4+1) Cycloaddition of Methylenecyclopropanes with 7‐Aryl‐1,3,5‐cycloheptatrienes by Triple Gold(I) Catalysis
Authors: Wang Yahui , Muratore Michael E. , Rong Zhouting , Echavarren Antonio M. 
Published: June 2014

Abstract7‐Aryl‐1,3,5‐cycloheptatrienes react intermolecularly with methylenecyclopropanes in a triple gold(I)‐catalyzed reaction to form cyclopentenes. The same formal (4+1) cycloaddition occurs with cyclobutenes. Other precursors of gold(I) carbenes can also be used as the C1 component of the cycloaddition.
A Reliable Aerosol‐Spray‐Assisted Approach to Produce and Optimize Amorphous Metal Oxide Catalysts for Electrochemical Water Splitting
Authors: Kuai Long , Geng Jing , Chen Changyu , Kan Erjie , Liu Yadong , Wang Qing , Geng Baoyou 
Published: June 2014

AbstractAn aerosol‐spray‐assisted approach (ASAA) is proposed and confirmed as a precisely controllable and continuous method to fabricate amorphous mixed metal oxides for electrochemical water splitting. The proportion of metal elements can be accurately controlled to within (5±5) %. The products can be sustainably obtained, which is highly suitable for industrial applications. ASAA was used to show that Fe6Ni10Ox is the best catalyst among the investigated Fe‐Ni‐Ox series with an overpotential of as low as 0.286 V (10 mA cm−2) and a Tafel slope of 48 mV/decade for the electrochemical oxygen evolution reaction. Therefore, this work contributes a versatile, continuous, and reliable way to produce and optimize amorphous metal oxide catalysts.
Preparation and characterization of membranes obtained from blends of acrylonitrile copolymers with poly(vinyl alcohol)
Authors: Sandu Teodor , Sârbu Andrei , Damian Celina Maria , Marin Adela , Vulpe Silviu , Budinova Temenuzhka , Tsyntsarski Boyko , Yardim M. Ferhat , Sirkecioglu Ahmet 
Published: June 2014

ABSTRACTNew microfiltration and ultrafiltration membranes were obtained using acrylonitrile‐vinyl acetate copolymers in mixture with poly(vinyl alcohol) (PVA). Thus, a blend polymer solution was prepared in dimethylsulfoxide (DMSO) and used to obtain bicomponent polymer membranes by phase inversion. The rheological behavior of the DMSO polymer solutions was, mostly, dilatant at low shear gradients and pseudo plastic with quasi Newtonian tendency at higher gradients. Membranes were characterized by Fourier transform infrared spectrometry (FTIR), optical microscopy, atomic force microscopy, thermal gravimetric analysis‐differential thermal gravimetry, and pure water flux (PWF). FTIR spectra displayed the characteristic bands for acrylonitrile, vinyl acetate, and PVA. The morphology and the porosity can be tailored by the preparation conditions. PVA allows controlling the size of the pores and enables, in principle, to use the resulted membranes as supports for enzyme immobilization. PVA content influences the thermal stability. PWF values depend on the copolymer, on the content in PVA, but also on the coagulation bath composition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41013.
Quantitative electroencephalography: A new approach to the diagnosis of cerebral dysfunction in systemic lupus erythematosus
Authors: Ritchlin Christopher T. , Chabot Robert J. , Alper Kenneth , Buyon Jill , Belmont H. Michael , Roubey Robert , Abramson Steven B. 
Published: June 2014

AbstractObjective. Neuropsychiatric manifestations are common in patients with systemic lupus erythematosus (SLE), but accurate diagnosis is often difficult. We conducted a prospective study to determine the utility of neurometric quantitative electroencephalography (QEEG) as an indicator of cerebral dysfunction in SLE patients.Methods. Fifty‐two SLE patients were divided into 4 groups based on the results of neuropsychiatric evaluations. These included patients with objective evidence of neuropsychiatric SLE (NPSLE), patients with neuropsychiatric symptoms, patients with no evidence of NPSLE, and patients with a prior history of NPSLE. All QEEG findings were compared with data in an age‐regressed normative database and with findings in an independent sample of normal subjects.Results. QEEG sensitivity was 87%, and specificity was 75%. QEEG results were abnormal in 74% of the SLE patients with neuropsychiatric symptoms and in 28% of the patients with no evidence of active NPSLE. QEEG profiles varied as a function of the severity and type of neuropsychiatric manifestation present. Within this patient population, QEEG was more sensitive than magnetic resonance imaging, computed tomography scanning, or conventional EEG.Conclusion. Neurometric QEEG may be a sensitive indicator of cerebral dysfunction in patients with NPSLE and can differentiate patients with diverse neuropsychiatric manifestations. When combined with a careful clinical history and evaluation, QEEG provides information that may be useful for the early detection of NPSLE and for serial evaluation of disease activity and treatment efficacy.
Calixarene‐Based Chemosensors by Means of Click Chemistry
Authors: Song Miaomiao , Sun Zhongyue , Han Cuiping , Tian Demei , Li Haibing , Kim Jong Seung 
Published: June 2014

AbstractClick chemistry, a new strategy for organic chemistry, has been widely used in the chemical modification of calixarenes because of its reliability, specificity, biocompatibility, and efficiency. Click‐derived triazoles also play a critical role in sensing ions and molecules. This in‐depth review provides an overview of calixarene‐based chemosensors that incorporate click‐derived triazoles, and their three characteristics (chromogenic, fluorescence, and wettability) are reviewed.
Characterization and analysis of the molecular weight of lignin for biorefining studies
Authors: Tolbert Allison , Akinosho Hannah , Khunsupat Ratayakorn , Naskar Amit K. , Ragauskas Arthur J. 
Published: June 2014

AbstractThe molecular weight of lignin is a fundamental property that influences the recalcitrance of biomass and the valorization of lignin. The determination of the molecular weight of lignin in native biomass is dependent on the bioresources used and the isolation and purification procedures employed. The three most commonly employed isolation methods are milled wood lignin (MWL), cellulolytic enzyme lignin (CEL), and enzymatic mild acidolysis lignin (EMAL). Common characterization techniques for determining the molecular weight of lignin will be addressed, with an emphasis on gel permeation chromatography (GPC). This review also examines the mechanisms behind several biological, physical, and chemical pre‐treatments and their impact on the molecular weight of lignin. The number average molecular weight (Mn), weight average molecular weight (Mw) and polydispersity index (D) all vary in magnitude depending on the biomass source, pre‐treatment conditions, and isolation method. Additionally, there is a growing body of literature that supports changes in the molecular weight of lignin in response to genetic modifications in the lignin biosynthetic pathways. This review summarizes different procedures for obtaining the molecular weight of lignin that have been used in recent years and highlight future opportunities for applications of lignin. © 2014 Society of Chemical Industry and John Wiley & Sons, Ltd
Systematic Analysis of Single Droplet Coalescence
Authors: Villwock Jörn , Gebauer Felix , Kamp Johannes , Bart Hans‐Jörg , Kraume Matthias 
Published: June 2014

AbstractCoalescence behavior in liquid‐liquid dispersions is controlled by various parameters. Thus, data from different research groups can differ significantly. Dynamic coalescence processes were analyzed systematically with the EFCE standard test system toluene/water in two different research laboratories. After comparability was proven with standardized batch settling tests and drop rise velocity measurements, the influence of drop size ratio and varying NaCl and NaOH concentrations on coalescence probability was investigated. Since the ions led to a coalescence inhibition, no clear impact of drop size ratio could be observed. The analysis of drop contact showed longer contact times for increasing equivalent drop diameter. This promotes coalescence and corresponds to film drainage model.
Immobilisation of Flavin‐Adenine‐Dinucleotide‐Dependent Glucose Dehydrogenase α Subunit in Free‐Standing Graphitised Carbon Nanofiber Paper Using a Bifunctional Cross‐Linker for an Enzymatic Biofuel Cell
Authors: Fapyane Deby , Lee Yooseok , Lim Chyi Yan , Ahn Jou‐Hyeon , Kim Seon‐Won , Chang In Seop 
Published: June 2014

AbstractFree‐standing graphitised carbon nanofiber paper (GCNFp) is fabricated using a dispersion–filtration method and modified by non‐covalent functionalisation with 1‐pyrenebutyric acid N‐hydroxysuccinimide ester—a bifunctional linker reagent—through π–π stacking. This modified GCNFp is then used to immobilise enzymes, and together they form an electrode for enzymatic biofuel cell (EBFC) applications. This fabrication method is shown to be capable of providing a practical platform for enzyme–electrode electrical communication that is faster than comparable systems based on other carbon materials, as calculated from the heterogeneous electron‐transfer rate constant. The GCNFp‐based EBFC reaches a maximum power density at a glucose concentration of 100 mM, yielding 834.9±200, 262.9±15.6 and 147.2±4.70 μW cm−2 for flavin‐adenine‐dinucleotide‐dependent glucose dehydrogenase (FADGDH)–menadione, glucose oxidase (GOX)–menadione, and GOX‐only systems (as the anode), respectively, with laccase as the cathode.
Molecular Mechanism of a Hotdog‐Fold Acyl‐CoA Thioesterase
Authors: Cantu David C. , Ardèvol Albert , Rovira Carme , Reilly Peter J. 
Published: June 2014

AbstractThioesterases are enzymes that hydrolyze thioester bonds between a carbonyl group and a sulfur atom. They catalyze key steps in fatty acid biosynthesis and metabolism, as well as polyketide biosynthesis. The reaction molecular mechanism of most hotdog‐fold acyl‐CoA thioesterases remains unknown, but several hypotheses have been put forward in structural and biochemical investigations. The reaction of a human thioesterase (hTHEM2), representing a thioesterase family with a hotdog fold where a coenzyme A moiety is cleaved, was simulated by quantum mechanics/molecular mechanics metadynamics techniques to elucidate atomic and electronic details of its mechanism, its transition‐state conformation, and the free energy landscape of the process. A single‐displacement acid‐base‐like mechanism, in which a nucleophilic water molecule is activated by an aspartate residue acting as a base, was found, confirming previous experimental proposals. The results provide unambiguous evidence of the formation of a tetrahedral‐like transition state. They also explain the roles of other conserved active‐site residues during the reaction, especially that of a nearby histidine/serine pair that protonates the thioester sulfur atom, the participation of which could not be elucidated from mutation analyses alone.
Thermotropic Luminescent Clustomesogen Showing a Nematic Phase: A Combination of Experimental and Molecular Simulation Studies
Authors: Cortes Maria Amela , Dorson Frederick , Prévôt Marianne , Ghoufi Aziz , Fontaine Bruno , Goujon Florent , Gautier Régis , Cîrcu Viorel , Mériadec Cristelle , Artzner Franck , Folliot Hervé , Cordier Stéphane , Molard Yann 
Published: June 2014

AbstractOctahedral Mo6 nanoclusters are functionalized with two organic ligands containing cyanobiphenyl (CB) units, giving luminescent hybrid liquid crystals (LC). Although the mesogenic density around the bulky inorganic core is constant, the two hybrids show different LC properties. Interestingly, one of them shows a nematic phase, which is particularly rare for this kind of supermolecular system. This surprising result is explained by using large‐scale molecular dynamic simulations.
Facile Synthesis of Chiral Spirooxindole‐Based Isotetronic Acids and 5‐1H‐Pyrrol‐2‐ones through Cascade Reactions with Bifunctional Organocatalysts
Authors: Guo Wengang , Wang Xu , Zhang Boyu , Shen Shuai , Zhou Xin , Wang Peng , Liu Yan , Li Can 
Published: June 2014

AbstractUnprecedented organocatalyzed asymmetric cascade reactions have been developed for the facile synthesis of chiral spirooxindole‐based isotetronic acids and 5‐1H‐pyrrol‐2‐ones.The asymmetric 1,2‐addition reactions of α‐ketoesters to isatins and imines by using an acid–base bifunctional 6′‐OH cinchona alkaloid catalyst, followed by cyclization and enolization of the resulting adducts, gave chiral spiroisotetronic acids and 5‐1H‐pyrrol‐2‐ones, respectively, in excellent optical purities (up to 98 % ee). FT‐IR analysis supported the existence of hydrogen‐bonding interaction between the 6′‐OH group of the cinchona catalyst and an isatin carbonyl group, an interaction that might be crucial for catalyst activity and stereocontrol.
Synthesis of Cyclic Alkenylsiloxanes by Semihydrogenation: A Stereospecific Route to (Z)‐Alkenyl Polyenes
Authors: Elbert Bryony L. , Lim Diane S. W. , Gudmundsson Haraldur G. , O'Hanlon Jack A. , Anderson Edward A. 
Published: June 2014

AbstractCyclic alkenylsiloxanes were synthesized by semihydrogenation of alkynylsilanes—a reaction previously plagued by poor stereoselectivity. The silanes, which can be synthesized on multigram scale, undergo Hiyama–Denmark coupling to give (Z)‐alkenyl polyene motifs found in bioactive natural products. The ring size of the silane is crucial: five‐membered cyclic siloxanes also couple under fluoride‐free conditions, whilst their six‐membered homologues do not, enabling orthogonality within this structural motif.
On the Hydrostannylation of Aryl Propargylic Alcohols and Their Derivatives: Remarkable Differences in Both Regio‐ and Stereoselectivity in Radical‐ and Nonradical‐Mediated Transformations
Authors: Oderinde Martins S. , Froese Robert D. J. , Organ Michael G. 
Published: June 2014

AbstractHerein, we describe a highly regio‐ and stereoselective radical‐mediated and molecular‐oxygen (O2)‐dependent hydrostannylation of phenyl propargylic alcohols and their derivatives. There is a significant steric effect on the stereoselectivity of the tin‐radical addition. Further, the uncatalyzed regio‐ and stereoselective hydrostannylation of aryl propargylic alcohols with nBu3SnH and Ph3SnH is also described and occurs with near titration kinetics. Although the uncatalyzed addition with nBu3SnH gave a remarkable γ‐regioselectivity irrespective of the electronic nature of the aryl moiety, addition with Ph3SnH appears to be driven by the electronic nature of the aryl alkynes.
Improving Model and Data Integration Using MOSAIC as Central Data Management Platform
Authors: Kraus Robert , Fillinger Sandra , Tolksdorf Gregor , Minh Duc H. , Merchan‐Restrepo Victor A. , Wozny Günter 
Published: June 2014

AbstractIn this paper, the problem of the data and model management in the lifecycle of a process plant is addressed by presenting the database structure of the modeling and optimization platform MOSAIC. The first step of data integration is done by combining models and plant data into one central database. This has advantages for both plant design and plant optimization. Basic engineering workflows can then be improved. Several database configurations are presented to meet the different requirements with respect to security and open access.
Phase angle for prognostication of survival in patients with advanced cancer: Preliminary findings
Authors: Hui David , Bansal Swati , Morgado Margarita , Dev Rony , Chisholm Gary , Bruera Eduardo 
Published: June 2014

BACKGROUNDAccurate survival prediction is essential for decision‐making in cancer therapies and care planning. Objective physiologic measures may improve the accuracy of prognostication. In this prospective study, the authors determined the association of phase angle, handgrip strength, and maximal inspiratory pressure with overall survival in patients with advanced cancer.METHODSHospitalized patients with advanced cancer who were seen by palliative care specialists for consultation were enrolled. Information regarding phase angle, handgrip strength, maximal inspiratory pressure, and known prognostic factors including the Palliative Prognostic Score, Palliative Prognostic Index, serum albumin, and body composition was collected. Univariate and multivariate survival analysis were performed, and the correlation between phase angle and other prognostic variables was examined.RESULTSA total of 222 patients were enrolled. The average age of the patients was 55 years (range, 22 years‐79 years); 59% of the patients were female, with a mean Karnofsky performance status of 55 and a median overall survival of 106 days (95% confidence interval [95% CI], 71 days‐128 days). The median survival for patients with phase angle 2 to 2.9°, 3 to 3.9°, 4 to 4.9°, 5 to 5.9° and ≥ 6° was 35 days, 54 days, 112 days, 134 days, and 220 days, respectively (P = .001). On multivariate analysis, phase angle (hazards ratio [HR], 0.86‐per degree increase; 95% CI, 0.74‐0.99 increase [P = .04]), Palliative Prognostic Score (HR, 1.07; 95% CI, 1.02‐1.13 [P = .008]), serum albumin (HR, 0.67; 95% CI, 0.50‐0.91 [P = .009]), and fat‐free mass (HR, 0.98; 95% CI, 0.96‐0.99 [P = .02]) were found to be significantly associated with survival. Phase angle was found to be only weakly (γ < 0.4) associated with other prognostic variables.CONCLUSIONSPhase angle was found to be a novel predictor of poor survival, independent of established prognostic factors, in the advanced cancer setting. This objective and noninvasive tool may be useful for bedside prognostication. Cancer 2014;120:2207–2214. © 2014 American Cancer Society.