bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tricycloundecane Derivatives as Potential N‐Methyl‐D‐aspartate (NMDA) Receptor and Voltage‐Gated Calcium Channel Modulators
Authors: Egunlusi Ayodeji O. , Malan Sarel F. , Joubert Jacques 
Published: May 2015

AbstractNeurodegenerative disorders are debilitating conditions characterised by progressive dysfunction and death of neuronal cells. Amidst the proposed mechanisms of neurodegeneration, the effects of excitotoxicity via N‐methyl‐D‐aspartate (NMDA) receptor stimulation and activation of voltage‐gated calcium channels (VGCC) on neuronal cells are prominent. This has led to the development of polycyclic cage molecules such as NGP1‐01, which exhibit neuroprotective properties through NMDA receptor and VGCC modulation. The medicinal potential of structurally related tricycloundecanes that are open‐cage or rearranged polycyclic moieties has not been explored. This study is therefore focused on the synthesis of a series of novel tricycloundecane derivatives and their ability to inhibit NMDA receptors and VGCC. Significant NMDA receptor inhibition was observed for tricyclo[6.2.1.02,7]undec‐9‐ene‐3,6‐dione (4, 78 %) and 6‐hydroxytricyclo[6.2.1.02,7]undec‐9‐en‐3‐one (5, >95 %) at a concentration of 100 μM. The highest inhibitory activity was observed for 6‐(benzylimino)tricyclo[6.2.1.02,7]undec‐9‐en‐3‐one (9, >95 %), which is in the same range as the inhibitory activity of MK‐801 (dizocilpine). In the VGCC inhibition assay, 6‐(benzylamino)tricyclo[6.2.1.02,7]undeca‐4,9‐dien‐3‐one (8, 34 %), 9 (38 %) and 2‐(benzylamino)‐3,6‐epoxytricyclo[6.2.1.05,10]undecan‐9‐ol (12, 40 %) showed statistically significant (p<0.05) VGCC inhibition.
Circuit level simulation of MRI receive chain using excitation derived from images
Authors: Jouda Mazin , Gruschke Oliver G. , Korvink Jan G. 
Published: May 2015

ABSTRACTWe introduce a novel component‐level simulation method with which to characterize the performance of the electronic interfaces and circuitry of a magnetic resonance imaging (MRI) receiver. The Matlab‐based toolbox first reconstructs idealized coil free induction decay signals from real MR images, then uses these signals to drive a transistor‐level and extracted‐layout simulation of the desired receiver architecture. The simulated receiver's outputs are read back into the toolbox, which then reconstructs the MR images. By comparing the reconstructed images with the original ones, important design characteristics, such as the circuit's noise figure, linearity, phase noise, and inter‐channel coupling, can be investigated in terms of image quality. To validate the method, a new MRI receiver architecture is designed and simulated. The architecture is a 16‐channel multiplexer, designed for a commercially available 0.35 μm CMOS technology, and employs both frequency‐division and time‐division multiplexing to form a combined output signal. The SNR degradation and the circuit's linearity determined from the MR images compare well with the SNR and linearity point predictions from conventional circuit simulations. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 102–113, 2015
On the Importance of CH/π and CH⋅⋅⋅HC Interactions in the Solid State Structure of 15‐Lipoxygenase Inhibitors Based on Eugenol Derivatives
Authors: Mirzaei Masoud , Nikpour Mohsen , Bauzá Antonio , Frontera Antonio 
Published: May 2015

AbstractIn this manuscript the X‐ray structures of two potent and known inhibitors of 15‐lipoxygenase, that is, 4‐allyl‐2‐methoxyphenyl‐1‐admantanecarboxylate (1) and allyl‐2‐methoxyphenyl‐1‐cyclohexanecarboxylate (2), are reported. Their solid‐state architectures show that they have a strong ability to establish CH/π and CH⋅⋅⋅HC interactions. For the former interaction, the adamantane or cyclohexane moieties are the CH donors and the electron‐rich methoxyphenyl ring is the π system. For the latter, the CH bonds belong to the aliphatic rings of the inhibitors. Interestingly, the active site of lipoxygenase enzyme family is rich in isoleucine and leucine amino acids that participate in the binding of the unsaturated fatty acid substrate by means of multiple hydrophobic CH⋅⋅⋅HC interactions. By means of theoretical calculations, we analyze the ability of compounds 1 and 2 to establish CH/π and CH⋅⋅⋅HC interactions in the solid state.
A Superhydrophobic Sponge with Hierarchical Structure as an Efficient and Recyclable Oil Absorbent
Authors: Liu Qin , Meng Kai , Ding Kui , Wang Yaobing 
Published: May 2015

AbstractOil/water separation is a worldwide challenge due to frequent oil spillages, and high‐performance absorbents are in high demand. In this work, a superhydrophobic sponge was fabricated by the polymerization of aniline, with subsequent simple immersion in n‐dodecylthiol. The polyaniline (PANI) constructed a nanoscale rough surface on the three‐dimension (3D) network of melamine sponge while n‐dodecylthiol reduced surface energy, thus lead to the superhydrophobicity. This superhydrophobic sponge could absorb a broad spectrum of oil and organics efficiently, with the highest 122 times of its own weight absorption capacity. Owing to the strong mechanical elasticity inherited from the pristine melamine sponge and stable adhesion of PANI, this sponge exhibited good recyclability through squeezing. More importantly, the fabrication procedure is facile, low‐cost and easily scalable. Thus, this superhydrophobic sponge is highly promising for absorption oil from water.
Carbon Nanofibers as Advanced Pd Catalyst Supports for the Air Electrode of Alkaline Metal–Air Batteries
Authors: Alegre Cinthia , Modica Esterina , Lo Vecchio Carmelo , Sebastián David , Lázaro María J. , Aricò Antonino S. , Baglio Vincenzo 
Published: May 2015

AbstractCarbon nanofibers are investigated as a support for Pd catalysts. The electrochemical behavior of these catalysts for both the oxygen reduction and oxygen evolution reactions is investigated in a half‐cell configuration in alkaline solution (6 M KOH) at room temperature. The catalysts are compared with an internal benchmark consisting of Pd supported on Vulcan. Stress tests are also performed to assess the stability of the catalysts under the highly corrosive conditions occurring at the positive electrode, especially during oxygen evolution (high potential). Pd catalysts supported on carbon nanofibers show promising stability characteristics for applications as bifunctional oxygen catalysts in metal–air batteries.
Definitive Insight into the Graphite Oxide Reduction Mechanism by Deuterium Labeling
Authors: Jankovský Ondřej , Šimek Petr , Luxa Jan , Sedmidubský David , Tomandl Ivo , Macková Anna , Mikšová Romana , Malinský Petr , Pumera Martin , Sofer Zdeněk 
Published: May 2015

AbstractThe reduction of graphite oxide is one of the most important reactions in the production of graphene in gram quantities. The mechanisms of these widely used reactions are poorly understood. The mechanism of the chemical reduction of two different graphite oxides prepared by the chlorate (Hofmann method) and permanganate methods (Hummers method) has been investigated. Three different reduction agents, lithium tetrahydridoaluminate, sodium tetrahydridoborate, and lithium tetrahydridoborate, as well as their deuterated counterparts, were used for the reduction of graphite oxide. Reduced graphite oxides were analyzed by scanning electron microscopy, energy‐dispersive spectroscopy, elemental combustion analysis, Raman spectroscopy, high‐resolution X‐ray photoelectron spectroscopy, and simultaneous thermal analysis. The concentration of boron incorporated into graphene was measured by prompt gamma activation analysis. Rutherford back‐scattering spectroscopy and elastic recoil detection analysis were used for the determination of the elemental composition, including deuterium concentration, as evidence of CH bond formation.
3 D Hierarchical Porous Carbon for Supercapacitors Prepared from Lignin through a Facile Template‐Free Method
Authors: Zhang Wenli , Lin Haibo , Lin Zheqi , Yin Jian , Lu Haiyan , Liu Dechen , Zhao Mingzhu 
Published: May 2015

AbstractLignin‐derived hierarchical porous carbon (LHPC) was prepared through a facile template‐free method. Solidification of the lignin–KOH solution resulted in KOH crystalizing within lignin. The crystalized KOH particles in solid lignin acted both as template and activating agent in the heat‐treatment process. The obtained LHPC, exhibiting a 3D network, consisted of macroporous cores, mesoporous channels, and micropores. The LHPC comprised 12.27 at % oxygen‐containing groups, which resulted in pseudocapacitance. The LHPC displayed a capacitance of 165.0 F g−1 in 1 M H2SO4 at 0.05 A g−1, and the capacitance was still 123.5 F g−1 even at 10 A g−1. The LHPC also displayed excellent cycling stability with capacitance retention of 97.3 % after 5000 galvanostatic charge–discharge cycles. On account of the facile preparation of LHPC, this paper offers a facile alternative method for the preparation of hierarchical porous carbon for electrochemical energy storage devices.
On the Conductance of the Gas Discharge Plasma at Space Anisotropic Excitation
Authors: Zhechev D. , Steflekova V. , Costello J. T. , Bundaleska N. 
Published: May 2015

AbstractThe galvanic manifestation of two transformations of degenerate magnetic states of the neon atom, namely self‐alignment → non‐alignment and alignment ↔ orientation is studied by monitoring the voltage across the discharge in a range of hollow cathode discharge (HCD) lamps. The application of a magnetic field to the discharge disorders the self‐alignment. Alignment and orientation are optically induced and their effect on the discharge conductance is compared by measuring the optogalvanic signals. The degenerate states investigated are found to contribute to the gas discharge conductance in a manner which depends on their degree of coherence. Various hollow cathode discharge media are studied including Ne/As, Ne/Cu, Ne/Ni, Ne/Cd, Ne/Li and Ne/Ca in the corresponding trademarked HCD spectral lamps. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solvothermal Synthesis of Tetravalent Uranium with Isophthalate or Pyromellitate Ligands
Authors: Falaise Clément , Delille Jason , Volkringer Christophe , Loiseau Thierry 
Published: May 2015

AbstractThree new coordination polymers bearing tetravalent uranium have been isolated with the O‐donor ligands such as isophthalate (1,3‐bdc) or pyromellitate (btec). The compounds 1 and 3 have been solvothermaly synthesized in N,N‐dimethylformamide (DMF). The crystal structure of U(1,3‐bdc)2(DMF) (1) is built up from discrete tricapped trigonal‐primastic UO9 units, for which one carbonyl oxygen atom from DMF is bound to uranium. The connection of the UO9 units with the isophthalate linkers occurs in a chelating and bidentate fashion and gives rise to the formation of a 3D framework, delimiting narrow channels running along the [101] direction. Upon heating, the DMF molecules are removed, generating the second phase U(1,3‐bdc)2 (2) compound, closely related to 1. Indeed, the coordination environment of uranium is reduced to eight with a distorted square‐antiprismatic geometry. This transition induces the relative shrinkage of the network (ΔV = 23 %). The structure of the compound U(btec)(DMF)2 (3) also exhibits a 3D framework composed of an isolated bicapped square‐antiprismatic UO10 unit, for which two carbonyl oxygen atoms from DMF are bonded to uranium. Pyromellitate ensures the connection of the UO10 units through the carboxylate arms in a chelating mode. This results in the formation of a network with diamond‐shaped channels, developed along the c axis and encapsulating the DMF molecules. In contrast to 1, no stable phase is observed upon removing the DMF species by heating.
Europium‐Based Dinuclear Triple‐Stranded Helicate vs. Tetranuclear Quadruple‐Stranded Helicate: Effect of Stoichiometric Ratio on the Supramolecular Self‐Assembly
Authors: Malviya Amita , Jena Himanshu Sekhar , Mondal Amit Kumar , Konar Sanjit 
Published: May 2015

AbstractTwo europium‐based helicates, namely the dinuclear triple‐stranded helicate [Eu2L3] (1) and tetranuclear quadruple‐stranded helicate [Eu4L4(NO3)]3+ (2), were achieved by the self‐assembly of the succinohydrazone derived bis‐tridentate ligand (H2L) and Eu3+ ions in 1:1 and 1:2 ratios, respectively. Both the helicates were characterized by single‐crystal X‐ray analysis. Structural analysis of both the helicates revealed optically inactive 50:50 mixtures of left‐ (Λ) and right‐hand (Δ) helicates in one unit cell. In 1, both the europium centers lie along the three‐fold axis whereas in 2, four europium centers are arranged in a triangular fashion around the four‐fold axis, which passes through the center of the quadruple stranded helicate. In 2, the presence of a nitrate ion on the nucleation of the aesthetically pleasing tetranuclear quadruple stranded helicate is significant. Apart from the molar ratio, the role of the bridging modes of the ligand, anion and noncovalent interaction on the self‐assembly of two helicates are also discussed.
Synthesis of β‐Trifluoromethylated Ketones from Propargylic Alcohols by Visible Light Photoredox Catalysis
Authors: Park Sehyun , Joo Jung Min , Cho Eun Jin 
Published: May 2015

AbstractRegioselective trifluoromethylation at a remote position represents an important challenge in the development of biologically active molecules and functional materials. A practical method to access β‐trifluoromethyl ketones from readily available propargylic alcohols by visible light photocatalysis has been developed. Trifluoromethylation of propargylic alcohols with CF3I in the presence of Ru(bpy)3Cl2 as the photocatalyst followed by double‐bond migration/keto‐enol tautomerization provides β‐trifluoromethyl ketones as the final product.
Advancements in Aminofluorination of Alkenes and Alkynes: Convenient Access to β‐Fluoroamines
Authors: Chen Pinhong , Liu Guosheng 
Published: May 2015

AbstractDirect aminofluorination of alkenes enables the convenient synthesis of β‐fluorinated amine compounds, which are important and valuable skeletons in medicinal chemistry. In recent years this research field has received much attention and significant advancements have been made by different approaches. In this review, recently disclosed methodologies for the production of β‐fluorinated amines, based on electrophilic and metal‐catalyzed processes, are summarized and discussed. Finally, the outlook and perspectives for aminofluorination are also discussed.
Diastereoselective Construction of 3‐Aminooxindoles with Adjacent Stereocenters: Stereocontrolled Addition of γ‐Substituted Allylindiums to Isatin Ketimines
Authors: Aslam Nayyar Ahmad , Babu Srinivasarao Arulananda , Rani Soniya , Mahajan Shivam , Solanki Jagmohan , Yasuda Makoto , Baba Akio 
Published: May 2015

AbstractThe diastereoselective construction of 3‐allyl‐3‐aminooxindoles that have two adjacent stereocenters has been achieved by the In‐promoted Barbier‐type addition of γ‐substituted allylic halides to the C=N bond of isatin ketimines. The reactions of cinnamyl‐, crotyl‐, and geranylindium compounds with isatin ketimines proceeded in either aqueous or alcohol solution. The addition of a cyclohexenylindium species to an isatin ketimine was carried out in N,N‐dimethylformamide (DMF), and the addition of ethyl 4‐bromocrotonate to an isatin ketimine in EtOH gave oxindole‐based β‐amino acid scaffolds. In all of these processes, the reaction conditions were screened to obtain the respective 3‐allyl‐3‐aminooxindoles with very high stereoselectivity. In addition, plausible TS models are proposed, and representative synthetic transformations were carried out by using the oxindole‐based β‐amino acid scaffolds. Furthermore, the stereochemistry of representative compounds were unequivocally established by single‐crystal X‐ray structure analysis.
Intra‐Intermolecular Palladium‐Catalyzed Domino Reactions of Glycine Allylamides for the Synthesis of Diversely Functionalized Piperazinones
Authors: Broggini Gianluigi , Beccalli Egle M. , Borelli Tea , Brusa Filippo , Gazzola Silvia , Mazza Alberto 
Published: May 2015

AbstractEasily accessible N‐tosylglycine allylamides have been converted into diversely functionalized piperazinone derivatives by inter‐intramolecular oxidative domino palladium‐catalyzed reactions. Aminochlorination and aminoacetoxylation processes were achieved by employing CuCl2 and PhI(OAc)2 as the oxidizing agents to give 5‐chloromethyl‐ and 5‐acetoxymethyl‐substituted piperazinones, respectively.
Synthesis of Functionalized BODIPYs, BODIPY‐Corrole, and BODIPY‐Porphyrin Arrays with 1,2,3‐Triazole Linkers Using the 4‐Azido(tetrafluorophenyl)‐BODIPY Building Block
Authors: Golf Hartwig R. A. , Oltmanns Anna M. , Trieu Duc H. , Reissig Hans‐Ulrich , Wiehe Arno 
Published: May 2015

AbstractThe copper(I)‐catalyzed 1,3‐dipolar cycloaddition of 4‐azido(tetrafluorophenyl)boron‐dipyrrin (azido‐BODIPY) with diverse terminal alkynes, varying from simple alkyl‐substituted derivatives to alkynes with functional groups and carbohydrates, was successfully employed to obtain meso‐functionalized BODIPY derivatives through the 1,2,3‐triazole linkage. The scope of this reaction was extended to the preparation of di‐ and trivalent BODIPY systems through the use of appropriate alkynyl linkers. Moreover, the synthesis of hydroxyl‐ and pentafluorothio‐(SF5)‐substituted, 1,2,3‐triazole‐linked array systems consisting of porphyrins and corroles as the central scaffold, in combination with a BODIPY, was investigated. These covalently connected tetrapyrrole‐BODIPY arrays exemplify a versatile approach to the construction of multichromophore systems: the combination of 1,3‐dipolar cycloaddition and nucleophilic substitution on pentafluorophenyl‐substituted porphyrinoids. The systems designed herein could serve in various light‐harvesting applications and electron‐transfer studies.
Mechanism Switch in Mannich‐Type Reactions: ELF and NCI Topological Analyses of the Reaction between Nitrones and Lithium Enolates
Authors: Roca‐López David , Polo Victor , Tejero Tomás , Merino Pedro 
Published: May 2015

AbstractThe mechanism of the addition of lithium enolates derived from esters, ketones and aldehydes to nitrones (Mannich‐type reaction) has been studied using DFT methods. While the reactions with α‐methoxy and α‐methyl enolates takes place through a stepwise mechanism, consisting of an initial nucleophilic attack of the enolate to the nitrone carbon followed by a second nucleophilic attack of the nitrone oxygen to the formed carbonyl group, the reaction with α‐unsusbtituted enolates takes place through a one‐step mechanism. The IRC analysis shows the presence of a hidden intermediate in agreement with one kinetic step two stages process. The topological analysis of the electronic localization function (ELF) confirms that only when the first C–C bond is formed, does the C–O bond formation begin. The NCI analyses, are also in agreement with the formation of intermediates for α‐methoxy and α‐methyl enolates and a highly asynchronous one‐step process in the case of α‐unsusbtituted enolates.
Enabling Asymmetric Alkynylation of Azaaryl Aldehydes with Soai Autocatalyst
Authors: Funes‐Maldonado Matías , Sieng Bora , Amedjkouh Mohamed 
Published: May 2015

AbstractA new sequence of autocatalysis–catalysis in asymmetric alkynylation of azaaryl aldehydes in the presence of Soai (5‐pyrimidyl)alkanol as chiral catalyst is documented. The autocatalyst can be generated from almost racemic environment to up to 99.5 % ee and subsequently propagates this chirality to provide propargylic alcohols in up to 86 % ee.
Asymmetric Amplification Coupling Enantioselective Autocatalysis and Asymmetric Induction for Alkylation of Azaaryl Aldehydes
Authors: Romagnoli Carlo , Sieng Bora , Amedjkouh Mohamed 
Published: May 2015

AbstractHerein, we describe a chemical system combining asymmetric amplification of Soai's autocatalyst alongside a catalytic addition of Zn(iPr)2 to azaaryl aldehydes. Thus, Soai autocatalyst is amplified in situ from 11 to > 98 % ee and concomitantly catalyzes the alkylation of pyridine aldehydes to provide alkanols with up to 99 % ee. Also, exceptional amplifications of ee in one cycle are observed for both compounds produced throughout the reaction, probably as a result of interactions in a reaction network coupling enantioselective autocatalysis and asymmetric induction.
Synthesis of Perfluoroalkyl‐Substituted Vinylcyclopropanes by Way of Enhanced Neighboring Group Participation
Authors: Kelly Christopher B. , Mercadante Michael A. , Carnaghan Emma R. , Doherty Matthew J. , Fager Diana C. , Hauck John J. , MacInnis Allyson E. , Tilley Leon J. , Leadbeater Nicholas E. 
Published: May 2015

AbstractA simple, high yielding, two‐step, one‐pot protocol for the preparation of trifluoromethyl‐substituted vinylcyclopropanes from α‐CF3 homoallyl alcohols is disclosed. Destabilization of the cationic intermediate by the electron‐withdrawing CF3 group greatly enhances neighboring group participation of the alkene, allowing ring closure to predominate. The reaction can be extended to the difluoromethyl and pentafluoroethyl group, enabling the preparation of a diverse array of fluoroalkyl‐substituted vinylcyclopropanes.
Mesenchymal Stem Cells Repress Osteoblast Differentiation Under Osteogenic‐Inducing Conditions
Authors: Santos Thiago S. , Abuna Rodrigo P.F. , Castro Raucci Larissa M.S. , Teixeira Lucas N. , de Oliveira Paulo T. , Beloti Marcio M. , Rosa Adalberto L. 
Published: May 2015

ABSTRACTThis study was designed to investigate the influence of mesenchymal stem cells (MSCs) on osteoblast (OB) differentiation. Rat bone marrow MSCs were cultured either in growth medium that maintained a MSC phenotype or in osteogenic medium that induced differentiation into OBs. Then, cells were grown in two different culture conditions: indirect co‐culture of MSCs and OBs and OBs cultured in MSC‐conditioned medium. As a control culture condition, OBs were grown in osteogenic medium without the influence of MSCs. We evaluated cell proliferation, the gene expression of key bone markers, alkaline phosphatase (ALP) activity, bone sialoprotein (BSP) expression, and extracellular matrix mineralization. The results showed that, regardless of whether OBs were indirectly co‐cultured with MSCs or cultured in MSC‐conditioned medium, MSCs repressed OB differentiation, as evidenced by the downregulation of all evaluated bone marker genes, decreased ALP activity, inhibition of BSP protein expression, and reduced extracellular matrix mineralization. Taken together, these results indicate that despite the key role of both MSCs and OBs in the osteogenic process, the repressive effect of MSCs on OB differentiation in an osteogenic environment may represent a barrier to the strategy of using them together in cell‐based therapies to induce bone repair. J. Cell. Biochem. 116: 2896–2902, 2015. © 2015 Wiley Periodicals, Inc.
Measuring Local Government Service Delivery Performance: Challenges and (PARTIAL) Solutions in Indonesia
Authors: Lewis Blane D. , McCulloch Neil , Sacks Audrey 
Published: May 2015

AbstractIndonesia, like many developing countries around the world, is increasingly turning to the use of a range of intergovernmental incentives to encourage improved local government performance in the delivery of services. Central government has access to a number of plausible indicators with which to measure local performance and operationalise incentive‐based programmes. However, there are major reliability and validity concerns related to even the best among the available indicators, and these create significant challenges for their intended uses. Technical approaches can partially overcome measurement problems, but more and better data will eventually have to be collected. Furthermore, government will have to take significant care in its choice and employment of methods to assess performance in a competent and transparent manner. Copyright © 2015 John Wiley & Sons, Ltd.