bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of bromo‐substituted polyaniline with excellent antibacterial activity
Authors: Cai Wei , Wang Jixiao , Quan Xiaodong , Wang Zhi 
Published: August 2017

ABSTRACTBromo‐substituted polyaniline (Br‐PANI) is prepared by a novel strategy in which PANI is used as raw material, potassium bromate and potassium bromide as brominate regents. The obtained Br‐PANI is characterized by scanning electron microscopy, X‐ray photoelectron spectroscopy, elemental analysis, FTIR, UV–vis spectra, and TGA. The results clearly indicate that Br has successfully attached to the benzene ring of PANI by chemical bond. The behavior of Br‐PANI toward bacteria is characterized by plate counting, minimal inhibitory concentration, and minimal bactericidal concentration methods. The experimental results indicate that both doped and dedoped Br‐PANIs have long‐term antibacterial activities as compared to doped/dedoped PANI. What's more, the antibacterial abilities increase with increasing the Br/N molar ratio of the Br‐PANI. Thus Br‐PANI should be a kind of efficient and environmentally friendly antibacterial agent. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45657.
Study on microfracture mechanism of short glass fiber reinforced polycarbonate by using acoustic emission
Authors: Kato Atsushi , Hamada Shinya , Shimizu Satoshi 
Published: August 2017

ABSTRACTThe influence of the difference in wettability between glass fiber (GF) and polycarbonate (PC) on the microfractures of GF reinforced PC was investigated by using an acoustic emission (AE) method. In the case of well‐coupled GF‐reinforced PC, it is suggested that in the AE amplitude region higher than about 16 mV, microfracture related to scission of polymer chains occurs at the interfacial layer between GF and PC. On the other hand, in the case of poorly‐coupled GF‐reinforced PC under stress, debonding and interfacial slippage between GF and PC occurred below the yield stress of PC, whereas interfacial fracture and GF breakage occurred above the yield stress. Debonding and interfacial slippage between GF and the PC matrix were closely related to an AE amplitude smaller than about 16 mV. The relationship between stress and AE events is expressed in this case by the Eyring model. The activation energy of interfacial slippage between GF and PC was about 74 kJ/mol, which corresponds to the energy of chain‐backbone motion of PC in the glassy state. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45664.
Computertomografie – den Fasern auf der Spur
Authors: Schuler Frank , Breit Wolfgang , Schnell Jürgen , Schladitz Katja 
Published: August 2017

AbstractDie bildanalytische Auswertung von 3‐D‐Computertomografieaufnahmen ermöglicht es, die Orientierung, Verteilung und Menge von Fasern in einem zu untersuchenden Betonkörper zu bestimmen.Der folgende Bericht befasst sich mit der praktischen Anwendung dieses neuartigen Verfahrens zur Lösung typischer Fragestellungen des Bauingenieurwesens.Die Analyse von aus Tunneltübbings entnommenen Bohrkernen zur Untersuchung des Einflusses der Herstellart auf die Orientierung und räumliche Verteilung der Fasern zeigt beispielhaft die Anwendungsmöglichkeiten des Verfahrens. Der Fokus der durchgeführten Arbeiten lag hierbei auf der Festlegung des anzusetzenden Faktors zur Berücksichtigung der Faserorientierung nach DAfStb‐Richtlinie „Stahlfaserbeton“.
KLK14 interactions with HAI‐1 and HAI‐2 serine protease inhibitors: A molecular dynamics and relative free‐energy calculations study
Authors: Solís‐Calero Christian , Carvalho Hernandes F. 
Published: August 2017

AbstractKallikrein 14 (KLK14) is a serine protease linked to several pathologies including prostate cancer and positively correlates with Gleason score. Though KLK14 functioning in cancer is poorly understood, it has been implicated in HGF/Met signaling, given that KLK14 proteolytically inhibits HGF activator‐inhibitor 1 (HAI‐1), which strongly inhibits pro‐HGF activators, thereby contributing to tumor progression. In this work, KLK14 binding to either hepatocyte growth factor activator inhibitor type‐1 (HAI‐1) or type‐2 (HAI‐2) was essayed using homology modeling, molecular dynamic simulations and free‐energy calculations through MM/PBSA and MM/GBSA. KLK14 was successfully modeled. Calculated free energies suggested higher binding affinity for the KLK14/HAI‐1 interaction than for KLK14/HAI‐2. This difference in binding affinity is largely explained by the higher stability of the hydrogen‐bond networks in KLK14/HAI‐1 along the simulation trajectory. A key arginine residue in both HAI‐1 and HAI‐2 is responsible for their interaction with the S1 pocket in KLK14. Additionally, MM/GBSA free‐energy decomposition postulates that KLK14 Asp174 and Trp196 are hotspots for binding HAI‐1 and HAI‐2.
Tubulin acetylation accompanies autophagy development induced by different abiotic stimuli in Arabidopsis thaliana
Authors: Olenieva Vira , Lytvyn Dmytro , Yemets Alla , Bergounioux Catherine , Blume Yaroslav 
Published: August 2017

AbstractMicrotubules (MTs) play an important role in the regulation of autophagy development in yeast and animal as well as in plant cells. MTs participate in maturation and traffic of autophagosomes through their dynamic state changes and post‐translational modifications of tubulin, namely acetylation. We subjected Arabidopsis thaliana seedlings to metabolic‐, salt‐, osmotic stresses as well as irradiation of ultraviolet B and investigated the involvement of plant MTs in the development of stress‐induced autophagy via tubulin acetylation. For this purpose Arabidopsis thaliana line expressing autophagy‐related protein 8 h (atg8h)‐GFP was generated to investigate autophagy, applying the level of free GFP as an indicator of autophagy development. Using autophagosome confocal imaging and Western blot analysis of Atg8 post‐translational lipidation and synchronous GFP release it was shown that all examined stressful stimuli led to pronounced development of autophagy, particularly in different root tissues. Moreover, autophagy development was accompanied by α‐tubulin acetylation under all stressful conditions. Presented data indicate the possible role of the post‐translational acetylation of α‐tubulin in the mediation of plant stress‐induced autophagy.
Porcine spermatogonial stem cells self‐renew effectively in a three dimensional culture microenvironment
Authors: Park Ji Eun , Park Min Hee , Kim Min Seong , Park Yeo Reum , Yun Jung Im , Cheong Hee Tae , Kim Minseok , Choi Jung Hoon , Lee Eunsong , Lee Seung Tae 
Published: August 2017

AbstractGenerally, self‐renewal of spermatogonial stem cells (SSCs) is maintained in vivo in a three‐dimensional (3D) microenvironment consisting of the seminiferous tubule basement membrane, indicating the importance of the 3D microenvironment for in vitro culture of SSCs. Here, we report a 3D culture microenvironment that effectively maintains porcine SSC self‐renewal during culture. Porcine SSCs were cultured in an agarose‐based 3D hydrogel and in 2D culture plates either with or without feeder cells. Subsequently, the effects of 3D culture on the maintenance of undifferentiated SSCs were identified by analyzing cell colony formation and morphology, AP activity, and transcriptional and translational regulation of self‐renewal‐related genes and the effects on proliferation by analyzing cell viability and single cell‐derived colony number. The 3D culture microenvironment constructed using a 0.2% (w/v) agarose‐based 3D hydrogel showed the strongest maintenance of porcine SSC self‐renewal and induced significant improvements in proliferation compared with 2D culture microenvironments. These results demonstrate that self‐renewal of porcine SSCs can be maintained more effectively in a 3D than in a 2D culture microenvironment. Moreover, this will play a significant role in developing novel culture systems for SSCs derived from diverse species in the future, which will contribute to SSC‐related research.
Gitelman syndrome: a rare life‐threatening case of hypokalemic paralysis mimicking Guillain–Barré syndrome during pregnancy and review of the literature
Authors: Elkoundi Abdelghafour , Kartite Noureddine , Bensghir Mustapha , Doghmi Nawfal , Lalaoui Salim Jaafar 
Published: August 2017

Key Clinical MessageIn rare cases, patients with Gitelman syndrome may present with hypokalemic paralysis mimicking Guillain–Barré syndrome. The severity of resultant symptoms may be life‐threatening. Controversial drugs such as aldactone, amiloride, and eplerenone should be used in this situation despite the lack of safety data.
Aortic stent graft placement under extracorporeal membrane oxygenation in severe multiple trauma
Authors: Stroehle Mathias , Lederer Wolfgang , Schmid Stefan , Glodny Bernhard , Chemelli Andreas P. , Wiedermann Franz J. 
Published: August 2017

Key Clinical MessagePlacement of an aortic stent graft under extracorporeal membrane oxygenation was the life‐saving procedure in a case of severe head trauma and traumatic aortic dissection after injured by a railroad engine. Timely access to neurosurgery, heart surgery, and radiology providing minimal invasive interventions increase the chances of a favorable outcome.
Mechanism of Carbon Monoxide Dissociation on a Cobalt Fischer–Tropsch Catalyst
Authors: Chen Wei , Zijlstra Bart , Filot Ivo A. W. , Pestman Robert , Hensen Emiel J. M. 
Published: August 2017

AbstractThe way in which the triple bond in CO dissociates, a key reaction step in the Fischer–Tropsch (FT) reaction, is a subject of intense debate. Direct CO dissociation on a Co catalyst was probed by 12C16O/13C18O scrambling in the absence and presence of H2. The initial scrambling rate without H2 was significantly higher than the rate of CO consumption under CO hydrogenation conditions, which indicated that the surface contained sites sufficiently reactive to dissociate CO without the assistance of H atoms. Only a small fraction of the surface was involved in CO scrambling. The minor influence of CO scrambling and CO residence time on the partial pressure of H2 showed that CO dissociation was not affected by the presence of H2. The positive H2 reaction order was correlated to the fact that the hydrogenation of adsorbed C and O atoms was slower than CO dissociation. Temperature‐programmed in situ IR spectroscopy underpinned the conclusion that CO dissociation does not require H atoms.
Transfer Functions for Periodic Reactor Operation: Fundamental Methodology for Simple Reaction Networks
Authors: Meyer Dominik , Friedland Jens , Kohn Thiemo , Güttel Robert 
Published: August 2017

AbstractA method for frequency response analysis of chemical reactors with periodically modulated inlet concentration is presented and demonstrated for simple first‐order irreversible consecutive and parallel as well as reversible reactions applying an isothermal continuous stirred‐tank reactor (CSTR). The frequency response of these reaction types is studied by simulations in time and frequency domain, the latter being based on Laplace transformation of the material balance. The results allow for clearly distinguish between the quasi and relaxed steady state as well as the full transient region with impact on designing reactors for dynamic operation. Furthermore, the relation between the dynamic response and the time constants of the system is discussed.
A Novel Approach for Measuring Gas Solubility in Liquids Using a Tube‐in‐Tube Membrane Contactor
Authors: Wu Gaowei , Cao Enhong , Kuhn Simon , Gavriilidis Asterios 
Published: August 2017

AbstractA novel approach using a semipermeable Teflon AF‐2400 tube‐in‐tube membrane contactor was developed for the measurement of gas solubility in organic solvents. This membrane ensures gas saturation of liquids in continuous flow at a specific pressure and temperature. After liquid decompression, the amount of gas outgassed was measured with a bubble meter and used for solubility calculation. The proposed method was applied to the measurement of oxygen solubility in toluene and benzyl alcohol. Validation experiments were initially performed by comparing the obtained oxygen solubility in toluene with literature data. With higher temperature, the solubility of oxygen in benzyl alcohol was found to increase, indicating that the oxygen‐dissolving process is endothermic. Finally, an empirical correlation of Henry's law constant as a function of temperature was determined.
Molecular Dynamics Insights into Polyamine–DNA Binding Modes: Implications for Cross‐Link Selectivity
Authors: Bignon Emmanuelle , Chan Chen‐Hui , Morell Christophe , Monari Antonio , Ravanat Jean‐Luc , Dumont Elise 
Published: August 2017

AbstractBiogenic polyamines, which play a role in DNA condensation and stabilization, are ubiquitous and are found at millimolar concentration in the nucleus of eukaryotic cells. The interaction modes of three polyamines—putrescine (Put), spermine (Spm), and spermidine (Spd)—with a self‐complementary 16 base pair (bp) duplex, are investigated by all‐atom explicit‐solvent molecular dynamics. The length of the amine aliphatic chain leads to a change of the interaction mode from minor groove binding to major groove binding. Through all‐atom dynamics, noncovalent interactions that stabilize the polyamine–DNA complex and prefigure the reactivity, leading to the low‐barrier formation of deleterious DNA–polyamine cross‐links, after one‐electron oxidation of a guanine nucleobase, are unraveled. The binding strength is quantified from the obtained trajectories by molecular mechanics generalized Born surface area post‐processing (MM‐GBSA). The values of binding free energies provide the same affinity order, Put<Spm<Spd, as that determined by recent isothermal calorimetry measurements, with a satisfactory correlation, to validate the structural predictions. The binding modes and carbon–nitrogen distances along the series of polyamines illustrate the selectivity towards deleterious DNA–polyamine cross‐link formation through the extraction of average approaching distances between the C8 atom of guanines and the ammonium group. These results imply that the formation of DNA–polyamine cross‐links involves deprotonation of the guanine radical cation to attack the polyamines, which must be positively charged to lie in the vicinity of the B‐helix.
Excitonically Coupled States in Crystalline Coordination Networks
Authors: Haldar Ritesh , Mazel Antoine , Joseph Reetu , Adams Michael , Howard Ian A. , Richards Bryce S. , Tsotsalas Manuel , Redel Engelbert , Diring Stéphane , Odobel Fabrice , Wöll Christof 
Published: August 2017

AbstractWhen chromophores are brought into close proximity, noncovalent interactions (π–π/CH–π) can lead to the formation of excitonically coupled states, which bestow new photophysical properties upon the aggregates. Because the properties of the new states not only depend on the strength of intermolecular interactions, but also on the relative orientation, supramolecular assemblies, where these parameters can be varied in a deliberate fashion, provide novel possibilities for the control of photophysical properties. This work reports that core‐substituted naphthalene diimides (cNDIs) can be incorporated into surface‐mounted metal– organic structures/frameworks (SURMOFs) to yield optical properties strikingly different from conventional aggregates of such molecules, for example, formed in solution or by crystallization. Organic linkers are used, based on cNDIs, well‐known organic chromophores with numerous applications in different optoelectronic devices, to fabricate MOF thin films on transparent substrates. A thorough characterization of the properties of these highly ordered chromophoric assemblies reveals the presence of non‐emissive excited states in the crystalline material. Structural modulations provide further insights into the nature of the coupling that gives rise to an excited‐state energy level in the periodic structure.
Potassium (De‐)insertion Processes in Prussian Blue Particles: Ensemble versus Single Nanoparticle Behaviour
Authors: Zampardi Giorgia , Sokolov Stanislav V. , Batchelor‐McAuley Christopher , Compton Richard G. 
Published: August 2017

AbstractPotassium (de‐)insertion from Prussian blue (PB) is investigated at the single and multi‐particle scale. The electrochemical behaviour is found to differ between the two measurement types. At the single particle level, oxidation of the PB nanoparticles with concomitant K+ deinsertion occurs more readily than the associated reduction, relating to K+ insertion. In contrast, the cyclic voltammetry of PB in a composite electrode containing conductive additives and polymeric binder suggests the opposite behaviour. Implications for assessing battery materials are discussed.
[2.2]Paracyclophanes with N‐Heterocycles as Ligands for Mono‐ and Dinuclear Ruthenium(II) Complexes
Authors: Braun Carolin , Nieger Martin , Thiel Werner R. , Bräse Stefan 
Published: August 2017

Abstract[2.2]Paracyclophane, with its unique structure, allows the design of unusual 3D structures by functionalization of this rigid and stable hydrocarbon scaffold. Therefore different mono‐ and homodisubstituted [2.2]paracyclophanes with pyridyl, pyrimidyl and oxazolinyl substituents were developed in order to evaluate their ability as bridging ligands for two ruthenium centres. With the successfully synthesized [2.2]paracyclophane‐based N‐donor functions, the cycloruthenation reaction using [RuCl2(p‐cymene)]2 as precursor was explored. Compared to 2‐phenylpyridine, the [2.2]paracyclophane derivative is clearly inferior in the cycloruthenation reaction, resulting in poor yields for the neutral complexes. By addition of KPF6, the cationic complexes can be obtained in good yields and are formed diastereoselectively in case of a pyridyl substituent, resulting in only one diastereomer for dinuclear ruthenium complexes of bispyridyl‐substituted [2.2]paracyclophanes as bridging ligands.
Proton in a Confined Space: Structural Studies of H+⊂Crypt‐111 Iodide and Some Halogen‐Bonded Derivatives
Authors: Kumar Vijith , Pilati Tullio , Quici Silvio , Chierotti Michele R. , Nervi Carlo , Gobetto Roberto , Resnati Giuseppe 
Published: August 2017

AbstractInvited for the cover of this issue is the group of Giuseppe Resnati at the Politecnico di Milano. The image depicts proton cryptation by crypt‐111, the smallest cryptand and an effective proton sponge. Read the full text of the article at 10.1002/chem.201701699.
The Pathogenic A2V Mutant Exhibits Distinct Aggregation Kinetics, Metal Site Structure, and Metal Exchange of the Cu2+–Aβ Complex
Authors: Somavarapu Arun K. , Shen Fei , Teilum Kaare , Zhang Jingdong , Mossin Susanne , Thulstrup Peter W. , Bjerrum Morten J. , Tiwari Manish K. , Szunyogh Daniel , Søtofte Peter M. , Kepp Kasper P. , Hemmingsen Lars 
Published: August 2017

AbstractA prominent current hypothesis is that impaired metal ion homeostasis may contribute to Alzheimer's disease (AD). We elucidate the interaction of Cu2+ with wild‐type (WT) Aβ1–40 and the genetic variants A2T and A2V which display increasing pathogenicity as A2T<WT<A2V. Cu2+ significantly extends the lag phase in aggregation kinetics, in particular for the pathogenic A2V variant. Additionally, a rapid, initial, low intensity ThT response is observed, possibly reflecting formation of Cu2+ induced amorphous aggregates, as supported by atomic force microscopy (AFM) and circular dichroism (CD) spectroscopy, again most notably for the A2V variant. Electron paramagnetic resonance (EPR) spectroscopy gives pKa values for transition between two Cu2+ coordination geometries (component I and II) of 7.4 (A2T), 7.9 (WT), and 8.4 (A2V), that is, component I is stabilized at physiological pH in the order A2T<WT<A2V. 1H NMR relaxation exhibits the same trend for the non‐coordinating aromatic residues (A2T<WT<A2V), and implies markedly faster inter‐peptide Cu2+exchange for the A2V variant than for WT and A2T. We therefore hypothesize that component I of the Cu–Aβ complex is related to pathogenicity, accounting for both the pathogenic nature of the A2V variant and the protective nature of the A2T variant.
From Enzymes to Functional Materials—Towards Activation of Small Molecules
Authors: Möller Frauke , Piontek Stefan , Miller Reece G. , Apfel Ulf‐Peter 
Published: August 2017

AbstractThe design of non‐noble metal‐containing heterogeneous catalysts for the activation of small molecules is of utmost importance for our society. While nature possesses very sophisticated machineries to perform such conversions, rationally designed catalytic materials are rare. Herein, we aim to raise the awareness of the overall common design and working principles of catalysts incorporating aspects of biology, chemistry, and material sciences.
Coordination Behavior of a Planar Chiral Cyclic (Amino)(Ferrocenyl)Carbene Ligand in Iridium Complexes
Authors: Shikata Yuta , Yasue Risa , Yoshida Kazuhiro 
Published: August 2017

AbstractIridium complexes bearing a new type of chiral carbene ligand, cyclic (amino)(ferrocenyl)carbene (CAFeC), were prepared. The complexes, which are quite stable in air and moisture, were fully characterized by NMR spectroscopy and X‐ray diffraction analysis. The NMR spectra of the dicarbonyl complex [IrCl(CO)2(CAFeC)] showed signals for two isomers in solution, which were assigned to diastereomeric rotamers arising from the rotation of the chiral CAFeC ligand around the axes of the Ir−Ccarbene bond. IR spectroscopy of the dicarbonyl complex revealed that the donor strength of CAFeC is much higher than those of classic N‐heterocyclic carbenes (NHCs) and comparable to those of cyclic amino alkyl carbenes (CAACs).
Phosphinous Acid‐Assisted Hydration of Nitriles: Understanding the Controversial Reactivity of Osmium and Ruthenium Catalysts
Authors: González‐Fernández Rebeca , Crochet Pascale , Cadierno Victorio , Menéndez M. Isabel , López Ramón 
Published: August 2017

AbstractThe synthesis and catalytic behavior of the osmium(II) complexes [OsCl2(η6‐p‐cymene)(PR2OH)] [R=Me (2 a), Ph (2 b), OMe (2 c), OPh (2 d)] in nitrile hydration reactions is presented. Among them, the best catalytic results were obtained with the phosphinous acid derivative [OsCl2(η6‐p‐cymene)(PMe2OH)] (2 a), which selectively provided the desired primary amides in excellent yields and short times at 80 °C, employing directly water as solvent, and without the assistance of any basic additive (TOF values up to 200 h−1). The process was successful with aromatic, heteroaromatic, aliphatic, and α,β‐unsaturated organonitriles, and showed a high functional group tolerance. Indeed, complex 2 arepresents the most active and versatile osmium‐based catalyst for the hydration of nitriles reported so far in the literature. In addition, it exhibits a catalytic performance similar to that of its ruthenium analogue [RuCl2(η6‐p‐cymene)(PMe2OH)] (4). However, when compared to4, the osmium complex 2 aturned out to be faster in the hydration of less‐reactive aliphatic nitriles, whereas the opposite trend was generally observed with aromatic substrates. DFT calculations suggest that these differences in reactivity are mainly related to the ring strain associated with the key intermediate in the catalytic cycle, that is, a five‐membered metallacyclic species generated by intramolecular addition of the hydroxyl group of the phosphinous acid ligand to the metal‐coordinated nitrile.
Bismuthanes as Hemilabile Donors in an O2‐Activating Palladium(0) Complex
Authors: Materne Karolin , Braun‐Cula Beatrice , Herwig Christian , Frank Nicolas , Limberg Christian 
Published: August 2017

AbstractA xanthene‐based bismuthane/phosphane chelating ligand has been accessed that has enabled the synthesis of a palladium(0) bismuthane complex. The bismuthane donor proved to be hemilabile as it switched to a dangling position upon addition of O2 that gave a palladium(II) peroxide complex. Unlike the corresponding 4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene (Xantphos) palladium peroxide, the bismuth analogue could be employed for catalytic phosphane oxidation and oxidative phenol coupling.